Add working test

PROTOCOL.md

@@ -0,0 +1,396 @@
+Gute Einsicht — du hast recht: **nur Disk-Hashes** allein reichen nicht, der Sync-Client muss die **gesamte Objekt-Graph-Struktur** (Disk → Partition → RootDir → Dirs → Files → Chunks) erzeugen und der Server muss diese Meta-Objekte speichern/prüfen.
+Ich aktualisiere das Protokoll so, dass es komplett, binär und KI-implementierbar ist — mit klaren Message-Formaten, Meta-Objekt-Binärlayouts und Pseudocode für Client **(was er erzeugen / berechnen muss)** und für Server **(wie er prüfen & persistieren muss)**.
+
+Ich halte es pragmatisch: keine Kompression-Extensions, keine Encryption — alles einfach, später erweiterbar.
+
+---
+
+# Kurzüberblick (Was passiert)
+
+1. Client scannt Disk/Partition, chunked Dateien (4 MiB), berechnet Chunks-Hashes (BLAKE3-256, 32B).
+2. Client baut Binär-Meta-Objekte: FileObj, DirObj, PartitionObj, DiskObj, SnapshotObj (jeweils Body → `meta_hash = BLAKE3(body)`).
+3. Client spricht Server über TCP an (HELLO → AUTH), fragt in Batches nach fehlenden Chunks/Metas, sendet nur fehlende Chunks/Metas.
+4. Am Ende sendet er das Snapshot-Commit; Server validiert, schreibt Snapshot-Referenz (Server führt Pointer).
+
+---
+
+# Nachrichtengeneralstruktur (Envelopes)
+
+Jede Nachricht: fixer 24-Byte Header + Payload:
+
+```
+struct MsgHeader {
+    u8  cmd;               // Befehlscode (siehe Tabelle)
+    u8  flags;             // reserved
+    u8  reserved[2];
+    u8  session_id[16];    // 0..0 bevor AUTH_OK
+    u32 payload_len;       // LE
+}
+```
+
+Antwort-Nachrichten haben dieselbe Hülle.
+
+---
+
+# Command-Codes (u8)
+
+* 0x01 HELLO
+* 0x02 HELLO_OK
+* 0x10 AUTH_USERPASS
+* 0x11 AUTH_CODE
+* 0x12 AUTH_OK
+* 0x13 AUTH_FAIL
+* 0x20 BATCH_CHECK_CHUNK
+* 0x21 CHECK_CHUNK_RESP
+* 0x22 SEND_CHUNK
+* 0x23 CHUNK_OK
+* 0x24 CHUNK_FAIL
+* 0x30 BATCH_CHECK_META
+* 0x31 CHECK_META_RESP
+* 0x32 SEND_META
+* 0x33 META_OK
+* 0x34 META_FAIL
+* 0x40 SEND_SNAPSHOT (Snapshot-Commit)
+* 0x41 SNAPSHOT_OK
+* 0x42 SNAPSHOT_FAIL
+* 0xFF CLOSE
+
+---
+
+# Wichtige Designentscheidungen (Kurz)
+
+* **Hashes**: BLAKE3-256 (32 Bytes). Client berechnet alle Hashes (Chunks + Meta bodies).
+* **Chunks auf Wire**: unkomprimiert (einfach & verlässlich). Kompression wäre später Erweiterung.
+* **Meta-Objekt-Body**: kompakte binäre Strukturen (siehe unten). `meta_hash = BLAKE3(body)`.
+* **Batch-Checks**: Client fragt in Batches nach fehlenden Chunks/Metas (+ Server liefert nur die fehlenden Hashes zurück). Minimiert RTT.
+* **Server persistiert**: `chunks/<ab>/<cd>/<hash>.chk`, `meta/<type>/<ab>/<cd>/<hash>.meta`. Server verwaltet Snapshot-Pointers (z. B. `machines/<client>/snapshots/<id>.ref`).
+* **Snapshot Commit**: Server validiert Objekt-Graph vor Abschluss; falls etwas fehlt, sendet Liste zurück (Snapshot_FAIL mit missing list).
+
+---
+
+# Binary Payload-Formate
+
+Alle mehrteiligen Zähler / Längen sind little-endian (`LE`).
+
+## A) BATCH_CHECK_CHUNK (Client → Server)
+
+```
+payload:
+u32 count
+for i in 0..count:
+  u8[32] chunk_hash
+```
+
+## CHECK_CHUNK_RESP (Server → Client)
+
+```
+payload:
+u32 missing_count
+for i in 0..missing_count:
+  u8[32] missing_chunk_hash
+```
+
+## SEND_CHUNK (Client → Server)
+
+```
+payload:
+u8[32] chunk_hash
+u32   size
+u8[size] data   // raw chunk bytes
+```
+
+Server computes BLAKE3(data) and compares to chunk_hash; if equal -> speichert.
+
+## A) BATCH_CHECK_META
+
+```
+payload:
+u32 count
+for i in 0..count:
+  u8  meta_type   // 1=file,2=dir,3=partition,4=disk,5=snapshot
+  u8[32] meta_hash
+```
+
+## CHECK_META_RESP
+
+```
+payload:
+u32 missing_count
+for i in 0..missing_count:
+  u8  meta_type
+  u8[32] meta_hash
+```
+
+## SEND_META
+
+```
+payload:
+u8   meta_type      // 1..5
+u8[32] meta_hash
+u32  body_len
+u8[body_len] body_bytes   // the canonical body; server will BLAKE3(body_bytes) and compare to meta_hash
+```
+
+## SEND_SNAPSHOT (Commit)
+
+```
+payload:
+u8[32] snapshot_hash
+u32   body_len
+u8[body_len] snapshot_body  // Snapshot body same encoding as meta (server validates body hash == snapshot_hash)
+```
+
+Server validates that snapshot_body references only existing meta objects (recursive / direct check). If OK → creates persistent snapshot pointer and replies SNAPSHOT_OK; if not, reply SNAPSHOT_FAIL with missing list (same format as CHECK_META_RESP).
+
+---
+
+# Meta-Objekt-Binärformate (Bodies)
+
+> Client erzeugt `body_bytes` für jedes Meta-Objekt; `meta_hash = BLAKE3(body_bytes)`.
+
+### FileObj (meta_type = 1)
+
+```
+FileObjBody:
+u8  version (1)
+u32 fs_type_code        // e.g. 1=ext*, 2=ntfs, 3=fat32 (enum)
+u64 size
+u32 mode               // POSIX mode for linux; 0 for FS without
+u32 uid
+u32 gid
+u64 mtime_unixsec
+u32 chunk_count
+for i in 0..chunk_count:
+  u8[32] chunk_hash
+// optional: xattrs/ACLs TLV (not in v1)
+```
+
+### DirObj (meta_type = 2)
+
+```
+DirObjBody:
+u8 version (1)
+u32 entry_count
+for each entry:
+  u8 entry_type      // 0 = file, 1 = dir, 2 = symlink
+  u16 name_len
+  u8[name_len] name (UTF-8)
+  u8[32] target_meta_hash
+```
+
+### PartitionObj (meta_type = 3)
+
+```
+PartitionObjBody:
+u8 version (1)
+u32 fs_type_code
+u8[32] root_dir_hash   // DirObj hash for root of this partition
+u64 start_lba
+u64 end_lba
+u8[16] type_guid       // zeroed if unused
+```
+
+### DiskObj (meta_type = 4)
+
+```
+DiskObjBody:
+u8 version (1)
+u32 partition_count
+for i in 0..partition_count:
+  u8[32] partition_hash
+u64 disk_size_bytes
+u16 serial_len
+u8[serial_len] serial_bytes
+```
+
+### SnapshotObj (meta_type = 5)
+
+```
+SnapshotObjBody:
+u8 version (1)
+u64 created_at_unixsec
+u32 disk_count
+for i in 0..disk_count:
+  u8[32] disk_hash
+// optional: snapshot metadata (user, note) as TLV extension later
+```
+
+---
+
+# Ablauf (Pseudocode) — **Client-Seite (Sync-Client)**
+
+(Erzeugt alle Hashes; sendet nur fehlendes per Batch)
+
+```text
+FUNCTION client_backup(tcp_conn, computer_id, disks):
+    send_msg(HELLO{client_type=0, auth_type=0})
+    await HELLO_OK
+
+    send_msg(AUTH_USERPASS{username,password})
+    resp = await
+    if resp != AUTH_OK: abort
+    session_id = resp.session_id
+
+    // traverse per-partition to limit memory
+    snapshot_disk_hashes = []
+    FOR disk IN disks:
+        partition_hashes = []
+        FOR part IN disk.partitions:
+            root_dir_hash = process_dir(part.root_path, tcp_conn)
+            part_body = build_partition_body(part.fs_type, root_dir_hash, part.start, part.end, part.guid)
+            part_hash = blake3(part_body)
+            batch_check_and_send_meta_if_missing(tcp_conn, meta_type=3, [(part_hash,part_body)])
+            partition_hashes.append(part_hash)
+
+        disk_body = build_disk_body(partition_hashes, disk.size, disk.serial)
+        disk_hash = blake3(disk_body)
+        batch_check_and_send_meta_if_missing(tcp_conn, meta_type=4, [(disk_hash,disk_body)])
+        snapshot_disk_hashes.append(disk_hash)
+
+    snapshot_body = build_snapshot_body(now(), snapshot_disk_hashes)
+    snapshot_hash = blake3(snapshot_body)
+    // final TRY: ask server if snapshot can be committed (server will verify)
+    send_msg(SEND_SNAPSHOT(snapshot_hash, snapshot_body))
+    resp = await
+    if resp == SNAPSHOT_OK: success
+    else if resp == SNAPSHOT_FAIL: // server returns missing meta list
+        // receive missing metas; client should send the remaining missing meta/chunks (loop)
+        handle_missing_and_retry()
+```
+
+Hilfsfunktionen:
+
+```text
+FUNCTION process_dir(path, tcp_conn):
+    entries_meta = []   // list of (name, entry_type, target_hash)
+    collect a list meta_to_check_for_this_dir = []
+    FOR entry IN readdir(path):
+        IF entry.is_file:
+            file_hash = process_file(entry.path, tcp_conn)   // below
+            entries_meta.append((entry.name, 0, file_hash))
+        ELSE IF entry.is_dir:
+            subdir_hash = process_dir(entry.path, tcp_conn)
+            entries_meta.append((entry.name, 1, subdir_hash))
+        ELSE IF symlink:
+            symlink_body = build_symlink_body(target)
+            symlink_hash = blake3(symlink_body)
+            batch_check_and_send_meta_if_missing(tcp_conn, meta_type=1, [(symlink_hash, symlink_body)])
+            entries_meta.append((entry.name, 2, symlink_hash))
+
+    dir_body = build_dir_body(entries_meta)
+    dir_hash = blake3(dir_body)
+    batch_check_and_send_meta_if_missing(tcp_conn, meta_type=2, [(dir_hash,dir_body)])
+    RETURN dir_hash
+```
+
+```text
+FUNCTION process_file(path, tcp_conn):
+    chunk_hashes = []
+    FOR each chunk IN read_in_chunks(path, 4*1024*1024):
+        chunk_hash = blake3(chunk)
+        chunk_hashes.append(chunk_hash)
+    // Batch-check chunks for this file
+    missing = batch_check_chunks(tcp_conn, chunk_hashes)
+    FOR each missing_hash IN missing:
+        chunk_bytes = read_chunk_by_hash_from_disk(path, missing_hash) // or buffer earlier
+        send_msg(SEND_CHUNK {hash,size,data})
+        await CHUNK_OK
+
+    file_body = build_file_body(fs_type, size, mode, uid, gid, mtime, chunk_hashes)
+    file_hash = blake3(file_body)
+    batch_check_and_send_meta_if_missing(tcp_conn, meta_type=1, [(file_hash,file_body)])
+    RETURN file_hash
+```
+
+`batch_check_and_send_meta_if_missing`:
+
+* Send BATCH_CHECK_META for all items
+* Server returns list of missing metas
+* For each missing, send SEND_META(meta_type, meta_hash, body)
+* Await META_OK
+
+Bemerkung: batching per directory/file-group reduziert RTT.
+
+---
+
+# Ablauf (Pseudocode) — **Server-Seite (Sync-Server)**
+
+```text
+ON connection:
+  read HELLO -> verify allowed client type
+  send HELLO_OK OR HELLO_FAIL
+
+ON AUTH_USERPASS:
+  validate credentials
+  if ok: generate session_id (16B), send AUTH_OK{session_id}
+  else send AUTH_FAIL
+
+ON BATCH_CHECK_CHUNK:
+  read list of hashes
+  missing_list = []
+  for hash in hashes:
+    if not exists chunks/shard(hash): missing_list.append(hash)
+  send CHECK_CHUNK_RESP {missing_list}
+
+ON SEND_CHUNK:
+  read chunk_hash, size, data
+  computed = blake3(data)
+  if computed != chunk_hash: send CHUNK_FAIL{reason} and drop
+  else if exists chunk already: send CHUNK_OK
+  else: write atomic to chunks/<ab>/<cd>/<hash>.chk and send CHUNK_OK
+
+ON BATCH_CHECK_META:
+  similar: check meta/<type>/<hash>.meta exists — return missing list
+
+ON SEND_META:
+  verify blake3(body) == meta_hash; if ok write meta/<type>/<ab>/<cd>/<hash>.meta atomically; respond META_OK
+
+ON SEND_SNAPSHOT:
+  verify blake3(snapshot_body) == snapshot_hash
+  // Validate the object graph:
+  missing = validate_graph(snapshot_body) // DFS: disks -> partitions -> dirs -> files -> chunks
+  if missing not empty:
+    send SNAPSHOT_FAIL {missing (as meta list and/or chunk list)}
+  else:
+    store snapshot file and create pointer machines/<client_id>/snapshots/<id>.ref
+    send SNAPSHOT_OK {snapshot_id}
+```
+
+`validate_graph`:
+
+* parse snapshot_body → disk_hashes
+* for each disk_hash check meta exists; load disk meta → for each partition_hash check meta exists … recursively for dir entries -> file metas -> check chunk existence for each chunk_hash. Collect missing set and return.
+
+---
+
+# Verhalten bei `SNAPSHOT_FAIL`
+
+* Server liefert fehlende meta/chunk-Hashes.
+* Client sendet diese gezielt (batch) und wiederholt `SEND_SNAPSHOT` (retry).
+* Alternativ: Client kann beim ersten Versuch inkrementell alle benötigten metas/chunks hochladen (das ist die übliche Reihenfolge dieses Pseudocodes — so fehlt beim Commit nichts mehr).
+
+---
+
+# Speicherung / Pfade (Server intern)
+
+* `chunks/<ab>/<cd>/<hash>.chk`  (ab = first 2 hex chars; cd = next 2)
+* `meta/files/<ab>/<cd>/<hash>.meta`
+* `meta/dirs/<...>`
+* `meta/parts/...`
+* `meta/disks/...`
+* `meta/snapshots/<snapshot_hash>.meta`
+* `machines/<client_id>/snapshots/<snapshot_id>.ref` (Pointer -> snapshot_hash + timestamp)
+
+Atomic writes: `tmp -> rename`.
+
+---
+
+# Wichtige Implementations-Hinweise für die KI/Server-Implementierung
+
+* **Batching ist Pflicht**: Implementiere `BATCH_CHECK_CHUNK` & `BATCH_CHECK_META` effizient (Bitset, HashSet lookups).
+* **Limits**: begrenze `count` pro Batch (z. B. 1000) — Client muss chunk lists stückeln.
+* **Validation:** Server muss auf `SEND_SNAPSHOT` den Graph validieren (sonst verliert man Konsistenz).
+* **Atomic Snapshot Commit:** erst persistieren, wenn Graph vollständig vorhanden.
+* **SessionID**: muss in Header für alle Nachfolgemsgs verwendet werden.
+* **Perf:** parallelisiere Chunk-Uploads (mehrere TCP-Tasks) und erlaubt Server mehrere parallele Handshakes.
+* **Sicherheit:** produktiv TLS/TCP oder VPN; Rate-limit / brute-force Schutz; Provisioning-Codes mit TTL.

server/.sqlx/query-2d6e5810f76e780a4a9b54c5ea39d707be614eb304dc6b4f32d8b6d28464c4b5.json

@@ -0,0 +1,56 @@
+{
+  "db_name": "SQLite",
+  "query": "\n            SELECT pc.id, pc.code, pc.expires_at, pc.used, m.id as machine_id, m.user_id, u.username\n            FROM provisioning_codes pc\n            JOIN machines m ON pc.machine_id = m.id\n            JOIN users u ON m.user_id = u.id\n            WHERE pc.code = ? AND pc.used = 0\n            ",
+  "describe": {
+    "columns": [
+      {
+        "name": "id",
+        "ordinal": 0,
+        "type_info": "Integer"
+      },
+      {
+        "name": "code",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "expires_at",
+        "ordinal": 2,
+        "type_info": "Datetime"
+      },
+      {
+        "name": "used",
+        "ordinal": 3,
+        "type_info": "Bool"
+      },
+      {
+        "name": "machine_id",
+        "ordinal": 4,
+        "type_info": "Integer"
+      },
+      {
+        "name": "user_id",
+        "ordinal": 5,
+        "type_info": "Integer"
+      },
+      {
+        "name": "username",
+        "ordinal": 6,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      true,
+      false,
+      false,
+      true,
+      true,
+      false,
+      false
+    ]
+  },
+  "hash": "2d6e5810f76e780a4a9b54c5ea39d707be614eb304dc6b4f32d8b6d28464c4b5"
+}

server/.sqlx/query-43af0c22d05eca56b2a7b1f6eed873102d8e006330fd7d8063657d2df936b3fb.json

@@ -0,0 +1,26 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT id, user_id FROM machines WHERE id = ?",
+  "describe": {
+    "columns": [
+      {
+        "name": "id",
+        "ordinal": 0,
+        "type_info": "Integer"
+      },
+      {
+        "name": "user_id",
+        "ordinal": 1,
+        "type_info": "Integer"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      false,
+      false
+    ]
+  },
+  "hash": "43af0c22d05eca56b2a7b1f6eed873102d8e006330fd7d8063657d2df936b3fb"
+}

server/.sqlx/query-508e673540beae31730d323bbb52d91747bb405ef3d6f4a7f20776fdeb618688.json

@@ -0,0 +1,12 @@
+{
+  "db_name": "SQLite",
+  "query": "UPDATE provisioning_codes SET used = 1 WHERE id = ?",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": []
+  },
+  "hash": "508e673540beae31730d323bbb52d91747bb405ef3d6f4a7f20776fdeb618688"
+}

server/.sqlx/query-9f9215a05f729db6f707c84967f4f11033d39d17ded98f4fe9fb48f3d1598596.json

@@ -0,0 +1,32 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT id, username, password_hash FROM users WHERE username = ?",
+  "describe": {
+    "columns": [
+      {
+        "name": "id",
+        "ordinal": 0,
+        "type_info": "Integer"
+      },
+      {
+        "name": "username",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "password_hash",
+        "ordinal": 2,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      true,
+      false,
+      false
+    ]
+  },
+  "hash": "9f9215a05f729db6f707c84967f4f11033d39d17ded98f4fe9fb48f3d1598596"
+}

server/.sqlx/query-cc5f2e47cc53dd29682506ff84f07f7d0914e3141e62b470e84b3886b50764a1.json

@@ -0,0 +1,26 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT id, user_id FROM machines WHERE id = ? AND user_id = ?",
+  "describe": {
+    "columns": [
+      {
+        "name": "id",
+        "ordinal": 0,
+        "type_info": "Integer"
+      },
+      {
+        "name": "user_id",
+        "ordinal": 1,
+        "type_info": "Integer"
+      }
+    ],
+    "parameters": {
+      "Right": 2
+    },
+    "nullable": [
+      false,
+      false
+    ]
+  },
+  "hash": "cc5f2e47cc53dd29682506ff84f07f7d0914e3141e62b470e84b3886b50764a1"
+}

server/Cargo.lock

@@ -38,6 +38,18 @@ version = "1.0.99"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b0674a1ddeecb70197781e945de4b3b8ffb61fa939a5597bcf48503737663100"
 
+[[package]]
+name = "arrayref"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76a2e8124351fda1ef8aaaa3bbd7ebbcb486bbcd4225aca0aa0d84bb2db8fecb"
+
+[[package]]
+name = "arrayvec"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
+
 [[package]]
 name = "atoi"
 version = "2.0.0"
@@ -153,6 +165,15 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "bincode"
+version = "1.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "bitflags"
 version = "2.9.4"
@@ -162,6 +183,19 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "blake3"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3888aaa89e4b2a40fca9848e400f6a658a5a3978de7be858e209cafa8be9a4a0"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "cc",
+ "cfg-if",
+ "constant_time_eq",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -254,6 +288,12 @@ version = "0.9.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2459377285ad874054d797f3ccebf984978aa39129f6eafde5cdc8315b612f8"
 
+[[package]]
+name = "constant_time_eq"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c74b8349d32d297c9134b8c88677813a227df8f779daa29bfc29c183fe3dca6"
+
 [[package]]
 name = "core-foundation-sys"
 version = "0.8.7"
@@ -364,6 +404,16 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
+[[package]]
+name = "errno"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
+dependencies = [
+ "libc",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "etcetera"
 version = "0.8.0"
@@ -386,6 +436,12 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "fastrand"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.1"
@@ -903,6 +959,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
+
 [[package]]
 name = "litemap"
 version = "0.8.0"
@@ -1249,6 +1311,19 @@ version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56f7d92ca342cea22a06f2121d944b4fd82af56988c270852495420f961d4ace"
 
+[[package]]
+name = "rustix"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "rustls"
 version = "0.23.31"
@@ -1362,11 +1437,16 @@ dependencies = [
  "anyhow",
  "axum",
  "bcrypt",
+ "bincode",
+ "blake3",
+ "bytes",
  "chrono",
+ "hex",
  "rand",
  "serde",
  "serde_json",
  "sqlx",
+ "tempfile",
  "tokio",
  "tower-http",
  "uuid",
@@ -1712,6 +1792,19 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tempfile"
+version = "3.22.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "84fa4d11fadde498443cca10fd3ac23c951f0dc59e080e9f4b93d4df4e4eea53"
+dependencies = [
+ "fastrand",
+ "getrandom 0.3.3",
+ "once_cell",
+ "rustix",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.16"

server/Cargo.toml

@@ -14,4 +14,11 @@ uuid = { version = "1.0", features = ["v4", "serde"] }
 chrono = { version = "0.4", features = ["serde"] }
 tower-http = { version = "0.6.6", features = ["cors", "fs"] }
 anyhow = "1.0"
-rand = "0.8"
+rand = "0.8"
+blake3 = "1.5"
+bytes = "1.0"
+bincode = "1.3"
+hex = "0.4"
+
+[dev-dependencies]
+tempfile = "3.0"

server/src/controllers/machines.rs

@@ -87,6 +87,7 @@ impl MachinesController {
             id: row.get("id"),
             user_id: row.get("user_id"),
             uuid: Uuid::parse_str(&row.get::<String, _>("uuid")).unwrap(),
+            machine_id: row.get::<String, _>("uuid"),
             name: row.get("name"),
             created_at: row.get("created_at"),
         })
@@ -109,6 +110,7 @@ impl MachinesController {
                 id: row.get("id"),
                 user_id: row.get("user_id"),
                 uuid: Uuid::parse_str(&row.get::<String, _>("uuid")).unwrap(),
+                machine_id: row.get::<String, _>("uuid"),
                 name: row.get("name"),
                 created_at: row.get("created_at"),
             });

server/src/controllers/mod.rs

@@ -1,3 +1,4 @@
 pub mod auth;
 pub mod machines;
+pub mod snapshots;
 pub mod users;

server/src/controllers/snapshots.rs

@@ -0,0 +1,184 @@
+use crate::sync::storage::Storage;
+use crate::sync::meta::{MetaObj, FsType};
+use crate::sync::protocol::MetaType;
+use crate::utils::{error::*, models::*, DbPool};
+use serde::Serialize;
+use chrono::{DateTime, Utc};
+
+// Basic snapshot info for listing
+#[derive(Debug, Serialize)]
+pub struct SnapshotSummary {
+    pub id: String,
+    pub snapshot_hash: String,
+    pub created_at: String,
+}
+
+// Detailed snapshot info with disk/partition data
+#[derive(Debug, Serialize)]
+pub struct SnapshotDetails {
+    pub id: String,
+    pub snapshot_hash: String,
+    pub created_at: String,
+    pub disks: Vec<DiskInfo>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct DiskInfo {
+    pub serial: String,
+    pub size_bytes: u64,
+    pub partitions: Vec<PartitionInfo>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct PartitionInfo {
+    pub fs_type: String,
+    pub start_lba: u64,
+    pub end_lba: u64,
+    pub size_bytes: u64,
+}
+
+pub struct SnapshotsController;
+
+impl SnapshotsController {
+    pub async fn get_machine_snapshots(
+        pool: &DbPool,
+        machine_id: i64,
+        user: &User,
+    ) -> AppResult<Vec<SnapshotSummary>> {
+        // Verify machine access
+        let machine = sqlx::query!(
+            "SELECT id, user_id FROM machines WHERE id = ? AND user_id = ?",
+            machine_id,
+            user.id
+        )
+        .fetch_optional(pool)
+        .await
+        .map_err(|e| AppError::DatabaseError(e.to_string()))?;
+
+        if machine.is_none() {
+            return Err(AppError::NotFoundError("Machine not found or access denied".to_string()));
+        }
+
+        let _machine = machine.unwrap();
+
+        let storage = Storage::new("./data");
+        let mut snapshot_summaries = Vec::new();
+
+        // List all snapshots for this machine from storage
+        match storage.list_snapshots(machine_id).await {
+            Ok(snapshot_ids) => {
+                for snapshot_id in snapshot_ids {
+                    // Load snapshot reference to get hash and timestamp
+                    if let Ok(Some((snapshot_hash, created_at_timestamp))) = storage.load_snapshot_ref(machine_id, &snapshot_id).await {
+                        let created_at = DateTime::from_timestamp(created_at_timestamp as i64, 0)
+                            .unwrap_or_else(|| Utc::now())
+                            .format("%Y-%m-%d %H:%M:%S UTC")
+                            .to_string();
+
+                        snapshot_summaries.push(SnapshotSummary {
+                            id: snapshot_id,
+                            snapshot_hash: hex::encode(snapshot_hash),
+                            created_at,
+                        });
+                    }
+                }
+            },
+            Err(_) => {
+                // If no snapshots directory exists, return empty list
+                return Ok(Vec::new());
+            }
+        }
+
+        // Sort by creation time (newest first)
+        snapshot_summaries.sort_by(|a, b| b.created_at.cmp(&a.created_at));
+
+        Ok(snapshot_summaries)
+    }
+
+    pub async fn get_snapshot_details(
+        pool: &DbPool,
+        machine_id: i64,
+        snapshot_id: String,
+        user: &User,
+    ) -> AppResult<SnapshotDetails> {
+        // Verify machine access
+        let machine = sqlx::query!(
+            "SELECT id, user_id FROM machines WHERE id = ? AND user_id = ?",
+            machine_id,
+            user.id
+        )
+        .fetch_optional(pool)
+        .await
+        .map_err(|e| AppError::DatabaseError(e.to_string()))?;
+
+        if machine.is_none() {
+            return Err(AppError::NotFoundError("Machine not found or access denied".to_string()));
+        }
+
+        let _machine = machine.unwrap();
+
+        let storage = Storage::new("./data");
+
+        // Load snapshot reference to get hash and timestamp
+        let (snapshot_hash, created_at_timestamp) = storage.load_snapshot_ref(machine_id, &snapshot_id).await
+            .map_err(|_| AppError::NotFoundError("Snapshot not found".to_string()))?
+            .ok_or_else(|| AppError::NotFoundError("Snapshot not found".to_string()))?;
+
+        // Load snapshot metadata
+        let snapshot_meta = storage.load_meta(MetaType::Snapshot, &snapshot_hash).await
+            .map_err(|_| AppError::NotFoundError("Snapshot metadata not found".to_string()))?
+            .ok_or_else(|| AppError::NotFoundError("Snapshot metadata not found".to_string()))?;
+
+        if let MetaObj::Snapshot(snapshot_obj) = snapshot_meta {
+            let mut disks = Vec::new();
+
+            for disk_hash in snapshot_obj.disk_hashes {
+                if let Ok(Some(disk_meta)) = storage.load_meta(MetaType::Disk, &disk_hash).await {
+                    if let MetaObj::Disk(disk_obj) = disk_meta {
+                        let mut partitions = Vec::new();
+
+                        for partition_hash in disk_obj.partition_hashes {
+                            if let Ok(Some(partition_meta)) = storage.load_meta(MetaType::Partition, &partition_hash).await {
+                                if let MetaObj::Partition(partition_obj) = partition_meta {
+                                    let fs_type_str = match partition_obj.fs_type_code {
+                                        FsType::Ext => "ext",
+                                        FsType::Ntfs => "ntfs",
+                                        FsType::Fat32 => "fat32", 
+                                        FsType::Unknown => "unknown",
+                                    };
+
+                                    partitions.push(PartitionInfo {
+                                        fs_type: fs_type_str.to_string(),
+                                        start_lba: partition_obj.start_lba,
+                                        end_lba: partition_obj.end_lba,
+                                        size_bytes: (partition_obj.end_lba - partition_obj.start_lba) * 512,
+                                    });
+                                }
+                            }
+                        }
+
+                        disks.push(DiskInfo {
+                            serial: disk_obj.serial,
+                            size_bytes: disk_obj.disk_size_bytes,
+                            partitions,
+                        });
+                    }
+                }
+            }
+
+            // Convert timestamp to readable format
+            let created_at_str = DateTime::<Utc>::from_timestamp(created_at_timestamp as i64, 0)
+                .map(|dt| dt.format("%Y-%m-%d %H:%M:%S").to_string())
+                .unwrap_or_else(|| "Unknown".to_string());
+
+            Ok(SnapshotDetails {
+                id: snapshot_id,
+                snapshot_hash: hex::encode(snapshot_hash),
+                created_at: created_at_str,
+                disks,
+            })
+        } else {
+            Err(AppError::ValidationError("Invalid snapshot metadata".to_string()))
+        }
+    }
+}

server/src/main.rs

@@ -1,13 +1,14 @@
 mod controllers;
 mod routes;
 mod utils;
+mod sync;
 
 use anyhow::Result;
 use axum::{
     routing::{delete, get, post, put},
     Router,
 };
-use routes::{accounts, admin, auth as auth_routes, config, machines, setup};
+use routes::{accounts, admin, auth, config, machines, setup, snapshots};
 use std::path::Path;
 use tokio::signal;
 use tower_http::{
@@ -15,15 +16,19 @@ use tower_http::{
     services::{ServeDir, ServeFile},
 };
 use utils::init_database;
+use sync::{SyncServer, server::SyncServerConfig};
 
 #[tokio::main]
 async fn main() -> Result<()> {
     let pool = init_database().await?;
+    
+    let sync_pool = pool.clone();
+    
     let api_routes = Router::new()
         .route("/setup/status", get(setup::get_setup_status))
         .route("/setup/init", post(setup::init_setup))
-        .route("/auth/login", post(auth_routes::login))
+        .route("/auth/login", post(auth::login))
-        .route("/auth/logout", post(auth_routes::logout))
+        .route("/auth/logout", post(auth::logout))
         .route("/accounts/me", get(accounts::me))
         .route("/admin/users", get(admin::get_users))
         .route("/admin/users", post(admin::create_user_handler))
@@ -35,7 +40,10 @@ async fn main() -> Result<()> {
         .route("/machines/register", post(machines::register_machine))
         .route("/machines/provisioning-code", post(machines::create_provisioning_code))
         .route("/machines", get(machines::get_machines))
+        .route("/machines/{id}", get(machines::get_machine))
         .route("/machines/{id}", delete(machines::delete_machine))
+                        .route("/machines/{id}/snapshots", get(snapshots::get_machine_snapshots))
+        .route("/machines/{machine_id}/snapshots/{snapshot_id}", get(snapshots::get_snapshot_details))
         .layer(CorsLayer::permissive())
         .with_state(pool);
 
@@ -51,8 +59,18 @@ async fn main() -> Result<()> {
         println!("Warning: dist directory not found at {}", dist_path);
     }
 
+    let sync_config = SyncServerConfig::default();
+    let sync_server = SyncServer::new(sync_config.clone(), sync_pool);
+    
+    tokio::spawn(async move {
+        if let Err(e) = sync_server.start().await {
+            eprintln!("Sync server error: {}", e);
+        }
+    });
+
     let listener = tokio::net::TcpListener::bind("0.0.0.0:8379").await?;
-    println!("Server running on http://0.0.0.0:8379");
+    println!("HTTP server running on http://0.0.0.0:8379");
+    println!("Sync server running on {}:{}", sync_config.bind_address, sync_config.port);
 
     axum::serve(listener, app)
         .with_graceful_shutdown(shutdown_signal())

server/src/routes/machines.rs

@@ -43,6 +43,21 @@ pub async fn get_machines(
     Ok(success_response(machines))
 }
 
+pub async fn get_machine(
+    auth_user: AuthUser,
+    State(pool): State<DbPool>,
+    Path(machine_id): Path<i64>,
+) -> Result<Json<Machine>, AppError> {
+    let machine = MachinesController::get_machine_by_id(&pool, machine_id).await?;
+    
+    // Check if user has access to this machine
+    if auth_user.user.role != UserRole::Admin && machine.user_id != auth_user.user.id {
+        return Err(AppError::NotFoundError("Machine not found or access denied".to_string()));
+    }
+    
+    Ok(success_response(machine))
+}
+
 pub async fn delete_machine(
     auth_user: AuthUser,
     State(pool): State<DbPool>,

server/src/routes/mod.rs

@@ -4,3 +4,4 @@ pub mod config;
 pub mod machines;
 pub mod setup;
 pub mod accounts;
+pub mod snapshots;

server/src/routes/snapshots.rs

@@ -0,0 +1,32 @@
+use axum::{extract::{Path, State}, Json};
+use crate::controllers::snapshots::{SnapshotsController, SnapshotSummary, SnapshotDetails};
+use crate::utils::{auth::AuthUser, error::AppResult, DbPool};
+
+pub async fn get_machine_snapshots(
+    State(pool): State<DbPool>,
+    Path(machine_id): Path<i64>,
+    auth_user: AuthUser,
+) -> AppResult<Json<Vec<SnapshotSummary>>> {
+    let snapshots = SnapshotsController::get_machine_snapshots(
+        &pool,
+        machine_id,
+        &auth_user.user,
+    ).await?;
+    
+    Ok(Json(snapshots))
+}
+
+pub async fn get_snapshot_details(
+    State(pool): State<DbPool>,
+    Path((machine_id, snapshot_id)): Path<(i64, String)>,
+    auth_user: AuthUser,
+) -> AppResult<Json<SnapshotDetails>> {
+    let snapshot = SnapshotsController::get_snapshot_details(
+        &pool,
+        machine_id,
+        snapshot_id,
+        &auth_user.user,
+    ).await?;
+    
+    Ok(Json(snapshot))
+}

server/src/sync/meta.rs

@@ -0,0 +1,605 @@
+use bytes::{Buf, BufMut, Bytes, BytesMut};
+use std::io::{Error, ErrorKind, Result};
+use crate::sync::protocol::{Hash, MetaType};
+
+/// Filesystem type codes
+#[repr(u32)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FsType {
+    Ext = 1,
+    Ntfs = 2,
+    Fat32 = 3,
+    Unknown = 0,
+}
+
+impl From<u32> for FsType {
+    fn from(value: u32) -> Self {
+        match value {
+            1 => FsType::Ext,
+            2 => FsType::Ntfs,
+            3 => FsType::Fat32,
+            _ => FsType::Unknown,
+        }
+    }
+}
+
+/// Directory entry types
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EntryType {
+    File = 0,
+    Dir = 1,
+    Symlink = 2,
+}
+
+impl TryFrom<u8> for EntryType {
+    type Error = Error;
+
+    fn try_from(value: u8) -> Result<Self> {
+        match value {
+            0 => Ok(EntryType::File),
+            1 => Ok(EntryType::Dir),
+            2 => Ok(EntryType::Symlink),
+            _ => Err(Error::new(ErrorKind::InvalidData, "Unknown entry type")),
+        }
+    }
+}
+
+/// File metadata object
+#[derive(Debug, Clone)]
+pub struct FileObj {
+    pub version: u8,
+    pub fs_type_code: FsType,
+    pub size: u64,
+    pub mode: u32,
+    pub uid: u32,
+    pub gid: u32,
+    pub mtime_unixsec: u64,
+    pub chunk_hashes: Vec<Hash>,
+}
+
+impl FileObj {
+    pub fn new(
+        fs_type_code: FsType,
+        size: u64,
+        mode: u32,
+        uid: u32,
+        gid: u32,
+        mtime_unixsec: u64,
+        chunk_hashes: Vec<Hash>,
+    ) -> Self {
+        Self {
+            version: 1,
+            fs_type_code,
+            size,
+            mode,
+            uid,
+            gid,
+            mtime_unixsec,
+            chunk_hashes,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+        
+        buf.put_u8(self.version);
+        buf.put_u32_le(self.fs_type_code as u32);
+        buf.put_u64_le(self.size);
+        buf.put_u32_le(self.mode);
+        buf.put_u32_le(self.uid);
+        buf.put_u32_le(self.gid);
+        buf.put_u64_le(self.mtime_unixsec);
+        buf.put_u32_le(self.chunk_hashes.len() as u32);
+        
+        for hash in &self.chunk_hashes {
+            buf.put_slice(hash);
+        }
+        
+        Ok(buf.freeze())
+    }
+
+    pub fn deserialize(mut data: Bytes) -> Result<Self> {
+        if data.remaining() < 41 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "FileObj data too short"));
+        }
+
+        let version = data.get_u8();
+        if version != 1 {
+            return Err(Error::new(ErrorKind::InvalidData, "Unsupported FileObj version"));
+        }
+
+        let fs_type_code = FsType::from(data.get_u32_le());
+        let size = data.get_u64_le();
+        let mode = data.get_u32_le();
+        let uid = data.get_u32_le();
+        let gid = data.get_u32_le();
+        let mtime_unixsec = data.get_u64_le();
+        let chunk_count = data.get_u32_le() as usize;
+
+        if data.remaining() < chunk_count * 32 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "FileObj chunk hashes too short"));
+        }
+
+        let mut chunk_hashes = Vec::with_capacity(chunk_count);
+        for _ in 0..chunk_count {
+            let mut hash = [0u8; 32];
+            data.copy_to_slice(&mut hash);
+            chunk_hashes.push(hash);
+        }
+
+        Ok(Self {
+            version,
+            fs_type_code,
+            size,
+            mode,
+            uid,
+            gid,
+            mtime_unixsec,
+            chunk_hashes,
+        })
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        let serialized = self.serialize()?;
+        Ok(blake3::hash(&serialized).into())
+    }
+}
+
+/// Directory entry
+#[derive(Debug, Clone)]
+pub struct DirEntry {
+    pub entry_type: EntryType,
+    pub name: String,
+    pub target_meta_hash: Hash,
+}
+
+/// Directory metadata object
+#[derive(Debug, Clone)]
+pub struct DirObj {
+    pub version: u8,
+    pub entries: Vec<DirEntry>,
+}
+
+impl DirObj {
+    pub fn new(entries: Vec<DirEntry>) -> Self {
+        Self {
+            version: 1,
+            entries,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+        
+        buf.put_u8(self.version);
+        buf.put_u32_le(self.entries.len() as u32);
+        
+        for entry in &self.entries {
+            buf.put_u8(entry.entry_type as u8);
+            let name_bytes = entry.name.as_bytes();
+            buf.put_u16_le(name_bytes.len() as u16);
+            buf.put_slice(name_bytes);
+            buf.put_slice(&entry.target_meta_hash);
+        }
+        
+        Ok(buf.freeze())
+    }
+
+    pub fn deserialize(mut data: Bytes) -> Result<Self> {
+        if data.remaining() < 5 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "DirObj data too short"));
+        }
+
+        let version = data.get_u8();
+        if version != 1 {
+            return Err(Error::new(ErrorKind::InvalidData, "Unsupported DirObj version"));
+        }
+
+        let entry_count = data.get_u32_le() as usize;
+        let mut entries = Vec::with_capacity(entry_count);
+
+        for _ in 0..entry_count {
+            if data.remaining() < 35 {
+                return Err(Error::new(ErrorKind::UnexpectedEof, "DirObj entry too short"));
+            }
+
+            let entry_type = EntryType::try_from(data.get_u8())?;
+            let name_len = data.get_u16_le() as usize;
+            
+            if data.remaining() < name_len + 32 {
+                return Err(Error::new(ErrorKind::UnexpectedEof, "DirObj entry name/hash too short"));
+            }
+
+            let name = String::from_utf8(data.copy_to_bytes(name_len).to_vec())
+                .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in entry name"))?;
+
+            let mut target_meta_hash = [0u8; 32];
+            data.copy_to_slice(&mut target_meta_hash);
+
+            entries.push(DirEntry {
+                entry_type,
+                name,
+                target_meta_hash,
+            });
+        }
+
+        Ok(Self {
+            version,
+            entries,
+        })
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        let serialized = self.serialize()?;
+        Ok(blake3::hash(&serialized).into())
+    }
+}
+
+/// Partition metadata object
+#[derive(Debug, Clone)]
+pub struct PartitionObj {
+    pub version: u8,
+    pub fs_type_code: FsType,
+    pub root_dir_hash: Hash,
+    pub start_lba: u64,
+    pub end_lba: u64,
+    pub type_guid: [u8; 16],
+}
+
+impl PartitionObj {
+    pub fn new(
+        fs_type_code: FsType,
+        root_dir_hash: Hash,
+        start_lba: u64,
+        end_lba: u64,
+        type_guid: [u8; 16],
+    ) -> Self {
+        Self {
+            version: 1,
+            fs_type_code,
+            root_dir_hash,
+            start_lba,
+            end_lba,
+            type_guid,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+        
+        buf.put_u8(self.version);
+        buf.put_u32_le(self.fs_type_code as u32);
+        buf.put_slice(&self.root_dir_hash);
+        buf.put_u64_le(self.start_lba);
+        buf.put_u64_le(self.end_lba);
+        buf.put_slice(&self.type_guid);
+        
+        Ok(buf.freeze())
+    }
+
+    pub fn deserialize(mut data: Bytes) -> Result<Self> {
+        if data.remaining() < 69 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "PartitionObj data too short"));
+        }
+
+        let version = data.get_u8();
+        if version != 1 {
+            return Err(Error::new(ErrorKind::InvalidData, "Unsupported PartitionObj version"));
+        }
+
+        let fs_type_code = FsType::from(data.get_u32_le());
+        
+        let mut root_dir_hash = [0u8; 32];
+        data.copy_to_slice(&mut root_dir_hash);
+        
+        let start_lba = data.get_u64_le();
+        let end_lba = data.get_u64_le();
+        
+        let mut type_guid = [0u8; 16];
+        data.copy_to_slice(&mut type_guid);
+
+        Ok(Self {
+            version,
+            fs_type_code,
+            root_dir_hash,
+            start_lba,
+            end_lba,
+            type_guid,
+        })
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        let serialized = self.serialize()?;
+        Ok(blake3::hash(&serialized).into())
+    }
+}
+
+/// Disk metadata object
+#[derive(Debug, Clone)]
+pub struct DiskObj {
+    pub version: u8,
+    pub partition_hashes: Vec<Hash>,
+    pub disk_size_bytes: u64,
+    pub serial: String,
+}
+
+impl DiskObj {
+    pub fn new(partition_hashes: Vec<Hash>, disk_size_bytes: u64, serial: String) -> Self {
+        Self {
+            version: 1,
+            partition_hashes,
+            disk_size_bytes,
+            serial,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+        
+        buf.put_u8(self.version);
+        buf.put_u32_le(self.partition_hashes.len() as u32);
+        
+        for hash in &self.partition_hashes {
+            buf.put_slice(hash);
+        }
+        
+        buf.put_u64_le(self.disk_size_bytes);
+        
+        let serial_bytes = self.serial.as_bytes();
+        buf.put_u16_le(serial_bytes.len() as u16);
+        buf.put_slice(serial_bytes);
+        
+        Ok(buf.freeze())
+    }
+
+    pub fn deserialize(mut data: Bytes) -> Result<Self> {
+        println!("DiskObj::deserialize: input data length = {}", data.len());
+        
+        if data.remaining() < 15 {
+            println!("DiskObj::deserialize: data too short, remaining = {}", data.remaining());
+            return Err(Error::new(ErrorKind::UnexpectedEof, "DiskObj data too short"));
+        }
+
+        let version = data.get_u8();
+        println!("DiskObj::deserialize: version = {}", version);
+        if version != 1 {
+            println!("DiskObj::deserialize: unsupported version {}", version);
+            return Err(Error::new(ErrorKind::InvalidData, "Unsupported DiskObj version"));
+        }
+
+        let partition_count = data.get_u32_le() as usize;
+        println!("DiskObj::deserialize: partition_count = {}", partition_count);
+        
+        if data.remaining() < partition_count * 32 + 10 {
+            println!("DiskObj::deserialize: not enough data for partitions, remaining = {}, needed = {}", 
+                    data.remaining(), partition_count * 32 + 10);
+            return Err(Error::new(ErrorKind::UnexpectedEof, "DiskObj partitions too short"));
+        }
+
+        let mut partition_hashes = Vec::with_capacity(partition_count);
+        for i in 0..partition_count {
+            let mut hash = [0u8; 32];
+            data.copy_to_slice(&mut hash);
+            println!("DiskObj::deserialize: partition {} hash = {}", i, hex::encode(&hash));
+            partition_hashes.push(hash);
+        }
+
+        let disk_size_bytes = data.get_u64_le();
+        println!("DiskObj::deserialize: disk_size_bytes = {}", disk_size_bytes);
+        
+        let serial_len = data.get_u16_le() as usize;
+        println!("DiskObj::deserialize: serial_len = {}", serial_len);
+        
+        if data.remaining() < serial_len {
+            println!("DiskObj::deserialize: not enough data for serial, remaining = {}, needed = {}", 
+                    data.remaining(), serial_len);
+            return Err(Error::new(ErrorKind::UnexpectedEof, "DiskObj serial too short"));
+        }
+
+        let serial_bytes = data.copy_to_bytes(serial_len).to_vec();
+        println!("DiskObj::deserialize: serial_bytes = {:?}", serial_bytes);
+        
+        let serial = String::from_utf8(serial_bytes)
+            .map_err(|e| {
+                println!("DiskObj::deserialize: UTF-8 error: {}", e);
+                Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in serial")
+            })?;
+
+        println!("DiskObj::deserialize: serial = '{}'", serial);
+        println!("DiskObj::deserialize: successfully deserialized");
+
+        Ok(Self {
+            version,
+            partition_hashes,
+            disk_size_bytes,
+            serial,
+        })
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        let serialized = self.serialize()?;
+        Ok(blake3::hash(&serialized).into())
+    }
+}
+
+/// Snapshot metadata object
+#[derive(Debug, Clone)]
+pub struct SnapshotObj {
+    pub version: u8,
+    pub created_at_unixsec: u64,
+    pub disk_hashes: Vec<Hash>,
+}
+
+impl SnapshotObj {
+    pub fn new(created_at_unixsec: u64, disk_hashes: Vec<Hash>) -> Self {
+        Self {
+            version: 1,
+            created_at_unixsec,
+            disk_hashes,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+        
+        buf.put_u8(self.version);
+        buf.put_u64_le(self.created_at_unixsec);
+        buf.put_u32_le(self.disk_hashes.len() as u32);
+        
+        for hash in &self.disk_hashes {
+            buf.put_slice(hash);
+        }
+        
+        Ok(buf.freeze())
+    }
+
+    pub fn deserialize(mut data: Bytes) -> Result<Self> {
+        if data.remaining() < 13 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotObj data too short"));
+        }
+
+        let version = data.get_u8();
+        if version != 1 {
+            return Err(Error::new(ErrorKind::InvalidData, "Unsupported SnapshotObj version"));
+        }
+
+        let created_at_unixsec = data.get_u64_le();
+        let disk_count = data.get_u32_le() as usize;
+        
+        if data.remaining() < disk_count * 32 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotObj disk hashes too short"));
+        }
+
+        let mut disk_hashes = Vec::with_capacity(disk_count);
+        for _ in 0..disk_count {
+            let mut hash = [0u8; 32];
+            data.copy_to_slice(&mut hash);
+            disk_hashes.push(hash);
+        }
+
+        Ok(Self {
+            version,
+            created_at_unixsec,
+            disk_hashes,
+        })
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        let serialized = self.serialize()?;
+        Ok(blake3::hash(&serialized).into())
+    }
+}
+
+/// Meta object wrapper
+#[derive(Debug, Clone)]
+pub enum MetaObj {
+    File(FileObj),
+    Dir(DirObj),
+    Partition(PartitionObj),
+    Disk(DiskObj),
+    Snapshot(SnapshotObj),
+}
+
+impl MetaObj {
+    pub fn meta_type(&self) -> MetaType {
+        match self {
+            MetaObj::File(_) => MetaType::File,
+            MetaObj::Dir(_) => MetaType::Dir,
+            MetaObj::Partition(_) => MetaType::Partition,
+            MetaObj::Disk(_) => MetaType::Disk,
+            MetaObj::Snapshot(_) => MetaType::Snapshot,
+        }
+    }
+
+    pub fn serialize(&self) -> Result<Bytes> {
+        match self {
+            MetaObj::File(obj) => obj.serialize(),
+            MetaObj::Dir(obj) => obj.serialize(),
+            MetaObj::Partition(obj) => obj.serialize(),
+            MetaObj::Disk(obj) => obj.serialize(),
+            MetaObj::Snapshot(obj) => obj.serialize(),
+        }
+    }
+
+    pub fn deserialize(meta_type: MetaType, data: Bytes) -> Result<Self> {
+        match meta_type {
+            MetaType::File => Ok(MetaObj::File(FileObj::deserialize(data)?)),
+            MetaType::Dir => Ok(MetaObj::Dir(DirObj::deserialize(data)?)),
+            MetaType::Partition => Ok(MetaObj::Partition(PartitionObj::deserialize(data)?)),
+            MetaType::Disk => Ok(MetaObj::Disk(DiskObj::deserialize(data)?)),
+            MetaType::Snapshot => Ok(MetaObj::Snapshot(SnapshotObj::deserialize(data)?)),
+        }
+    }
+
+    pub fn compute_hash(&self) -> Result<Hash> {
+        match self {
+            MetaObj::File(obj) => obj.compute_hash(),
+            MetaObj::Dir(obj) => obj.compute_hash(),
+            MetaObj::Partition(obj) => obj.compute_hash(),
+            MetaObj::Disk(obj) => obj.compute_hash(),
+            MetaObj::Snapshot(obj) => obj.compute_hash(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_file_obj_serialization() {
+        let obj = FileObj::new(
+            FsType::Ext,
+            1024,
+            0o644,
+            1000,
+            1000,
+            1234567890,
+            vec![[1; 32], [2; 32]],
+        );
+
+        let serialized = obj.serialize().unwrap();
+        let deserialized = FileObj::deserialize(serialized).unwrap();
+
+        assert_eq!(obj.fs_type_code, deserialized.fs_type_code);
+        assert_eq!(obj.size, deserialized.size);
+        assert_eq!(obj.chunk_hashes, deserialized.chunk_hashes);
+    }
+
+    #[test]
+    fn test_dir_obj_serialization() {
+        let entries = vec![
+            DirEntry {
+                entry_type: EntryType::File,
+                name: "test.txt".to_string(),
+                target_meta_hash: [1; 32],
+            },
+            DirEntry {
+                entry_type: EntryType::Dir,
+                name: "subdir".to_string(),
+                target_meta_hash: [2; 32],
+            },
+        ];
+
+        let obj = DirObj::new(entries);
+        let serialized = obj.serialize().unwrap();
+        let deserialized = DirObj::deserialize(serialized).unwrap();
+
+        assert_eq!(obj.entries.len(), deserialized.entries.len());
+        assert_eq!(obj.entries[0].name, deserialized.entries[0].name);
+        assert_eq!(obj.entries[1].entry_type, deserialized.entries[1].entry_type);
+    }
+
+    #[test]
+    fn test_hash_computation() {
+        let obj = FileObj::new(FsType::Ext, 1024, 0o644, 1000, 1000, 1234567890, vec![]);
+        let hash1 = obj.compute_hash().unwrap();
+        let hash2 = obj.compute_hash().unwrap();
+        assert_eq!(hash1, hash2);
+
+        let obj2 = FileObj::new(FsType::Ext, 1025, 0o644, 1000, 1000, 1234567890, vec![]);
+        let hash3 = obj2.compute_hash().unwrap();
+        assert_ne!(hash1, hash3);
+    }
+}

server/src/sync/mod.rs

@@ -0,0 +1,8 @@
+pub mod protocol;
+pub mod server;
+pub mod storage;
+pub mod session;
+pub mod meta;
+pub mod validation;
+
+pub use server::SyncServer;

server/src/sync/protocol.rs

@@ -0,0 +1,620 @@
+use bytes::{Buf, BufMut, Bytes, BytesMut};
+use std::io::{Error, ErrorKind, Result};
+
+/// Command codes for the sync protocol
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Command {
+    Hello = 0x01,
+    HelloOk = 0x02,
+    AuthUserPass = 0x10,
+    AuthCode = 0x11,
+    AuthOk = 0x12,
+    AuthFail = 0x13,
+    BatchCheckChunk = 0x20,
+    CheckChunkResp = 0x21,
+    SendChunk = 0x22,
+    ChunkOk = 0x23,
+    ChunkFail = 0x24,
+    BatchCheckMeta = 0x30,
+    CheckMetaResp = 0x31,
+    SendMeta = 0x32,
+    MetaOk = 0x33,
+    MetaFail = 0x34,
+    SendSnapshot = 0x40,
+    SnapshotOk = 0x41,
+    SnapshotFail = 0x42,
+    Close = 0xFF,
+}
+
+impl TryFrom<u8> for Command {
+    type Error = Error;
+
+    fn try_from(value: u8) -> Result<Self> {
+        match value {
+            0x01 => Ok(Command::Hello),
+            0x02 => Ok(Command::HelloOk),
+            0x10 => Ok(Command::AuthUserPass),
+            0x11 => Ok(Command::AuthCode),
+            0x12 => Ok(Command::AuthOk),
+            0x13 => Ok(Command::AuthFail),
+            0x20 => Ok(Command::BatchCheckChunk),
+            0x21 => Ok(Command::CheckChunkResp),
+            0x22 => Ok(Command::SendChunk),
+            0x23 => Ok(Command::ChunkOk),
+            0x24 => Ok(Command::ChunkFail),
+            0x30 => Ok(Command::BatchCheckMeta),
+            0x31 => Ok(Command::CheckMetaResp),
+            0x32 => Ok(Command::SendMeta),
+            0x33 => Ok(Command::MetaOk),
+            0x34 => Ok(Command::MetaFail),
+            0x40 => Ok(Command::SendSnapshot),
+            0x41 => Ok(Command::SnapshotOk),
+            0x42 => Ok(Command::SnapshotFail),
+            0xFF => Ok(Command::Close),
+            _ => Err(Error::new(ErrorKind::InvalidData, "Unknown command code")),
+        }
+    }
+}
+
+/// Message header structure (24 bytes fixed)
+#[derive(Debug, Clone)]
+pub struct MessageHeader {
+    pub cmd: Command,
+    pub flags: u8,
+    pub reserved: [u8; 2],
+    pub session_id: [u8; 16],
+    pub payload_len: u32,
+}
+
+impl MessageHeader {
+    pub const SIZE: usize = 24;
+
+    pub fn new(cmd: Command, session_id: [u8; 16], payload_len: u32) -> Self {
+        Self {
+            cmd,
+            flags: 0,
+            reserved: [0; 2],
+            session_id,
+            payload_len,
+        }
+    }
+
+    pub fn serialize(&self) -> [u8; Self::SIZE] {
+        let mut buf = [0u8; Self::SIZE];
+        buf[0] = self.cmd as u8;
+        buf[1] = self.flags;
+        buf[2..4].copy_from_slice(&self.reserved);
+        buf[4..20].copy_from_slice(&self.session_id);
+        buf[20..24].copy_from_slice(&self.payload_len.to_le_bytes());
+        buf
+    }
+
+    pub fn deserialize(buf: &[u8]) -> Result<Self> {
+        if buf.len() < Self::SIZE {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "Header too short"));
+        }
+
+        let cmd = Command::try_from(buf[0])?;
+        let flags = buf[1];
+        let reserved = [buf[2], buf[3]];
+        let mut session_id = [0u8; 16];
+        session_id.copy_from_slice(&buf[4..20]);
+        let payload_len = u32::from_le_bytes([buf[20], buf[21], buf[22], buf[23]]);
+
+        Ok(Self {
+            cmd,
+            flags,
+            reserved,
+            session_id,
+            payload_len,
+        })
+    }
+}
+
+/// A 32-byte BLAKE3 hash
+pub type Hash = [u8; 32];
+
+/// Meta object types
+#[repr(u8)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum MetaType {
+    File = 1,
+    Dir = 2,
+    Partition = 3,
+    Disk = 4,
+    Snapshot = 5,
+}
+
+impl TryFrom<u8> for MetaType {
+    type Error = Error;
+
+    fn try_from(value: u8) -> Result<Self> {
+        match value {
+            1 => Ok(MetaType::File),
+            2 => Ok(MetaType::Dir),
+            3 => Ok(MetaType::Partition),
+            4 => Ok(MetaType::Disk),
+            5 => Ok(MetaType::Snapshot),
+            _ => Err(Error::new(ErrorKind::InvalidData, "Unknown meta type")),
+        }
+    }
+}
+
+/// Protocol message types
+#[derive(Debug, Clone)]
+pub enum Message {
+    Hello {
+        client_type: u8,
+        auth_type: u8,
+    },
+    HelloOk,
+    AuthUserPass {
+        username: String,
+        password: String,
+        machine_id: i64,
+    },
+    AuthCode {
+        code: String,
+    },
+    AuthOk {
+        session_id: [u8; 16],
+    },
+    AuthFail {
+        reason: String,
+    },
+    BatchCheckChunk {
+        hashes: Vec<Hash>,
+    },
+    CheckChunkResp {
+        missing_hashes: Vec<Hash>,
+    },
+    SendChunk {
+        hash: Hash,
+        data: Bytes,
+    },
+    ChunkOk,
+    ChunkFail {
+        reason: String,
+    },
+    BatchCheckMeta {
+        items: Vec<(MetaType, Hash)>,
+    },
+    CheckMetaResp {
+        missing_items: Vec<(MetaType, Hash)>,
+    },
+    SendMeta {
+        meta_type: MetaType,
+        meta_hash: Hash,
+        body: Bytes,
+    },
+    MetaOk,
+    MetaFail {
+        reason: String,
+    },
+    SendSnapshot {
+        snapshot_hash: Hash,
+        body: Bytes,
+    },
+    SnapshotOk {
+        snapshot_id: String,
+    },
+    SnapshotFail {
+        missing_chunks: Vec<Hash>,
+        missing_metas: Vec<(MetaType, Hash)>,
+    },
+    Close,
+}
+
+impl Message {
+    /// Serialize message payload to bytes
+    pub fn serialize_payload(&self) -> Result<Bytes> {
+        let mut buf = BytesMut::new();
+
+        match self {
+            Message::Hello { client_type, auth_type } => {
+                buf.put_u8(*client_type);
+                buf.put_u8(*auth_type);
+            }
+            Message::HelloOk => {
+                // No payload
+            }
+            Message::AuthUserPass { username, password, machine_id } => {
+                let username_bytes = username.as_bytes();
+                let password_bytes = password.as_bytes();
+                buf.put_u16_le(username_bytes.len() as u16);
+                buf.put_slice(username_bytes);
+                buf.put_u16_le(password_bytes.len() as u16);
+                buf.put_slice(password_bytes);
+                buf.put_i64_le(*machine_id);
+            }
+            Message::AuthCode { code } => {
+                let code_bytes = code.as_bytes();
+                buf.put_u16_le(code_bytes.len() as u16);
+                buf.put_slice(code_bytes);
+            }
+            Message::AuthOk { session_id } => {
+                buf.put_slice(session_id);
+            }
+            Message::AuthFail { reason } => {
+                let reason_bytes = reason.as_bytes();
+                buf.put_u16_le(reason_bytes.len() as u16);
+                buf.put_slice(reason_bytes);
+            }
+            Message::BatchCheckChunk { hashes } => {
+                buf.put_u32_le(hashes.len() as u32);
+                for hash in hashes {
+                    buf.put_slice(hash);
+                }
+            }
+            Message::CheckChunkResp { missing_hashes } => {
+                buf.put_u32_le(missing_hashes.len() as u32);
+                for hash in missing_hashes {
+                    buf.put_slice(hash);
+                }
+            }
+            Message::SendChunk { hash, data } => {
+                buf.put_slice(hash);
+                buf.put_u32_le(data.len() as u32);
+                buf.put_slice(data);
+            }
+            Message::ChunkOk => {
+                // No payload
+            }
+            Message::ChunkFail { reason } => {
+                let reason_bytes = reason.as_bytes();
+                buf.put_u16_le(reason_bytes.len() as u16);
+                buf.put_slice(reason_bytes);
+            }
+            Message::BatchCheckMeta { items } => {
+                buf.put_u32_le(items.len() as u32);
+                for (meta_type, hash) in items {
+                    buf.put_u8(*meta_type as u8);
+                    buf.put_slice(hash);
+                }
+            }
+            Message::CheckMetaResp { missing_items } => {
+                buf.put_u32_le(missing_items.len() as u32);
+                for (meta_type, hash) in missing_items {
+                    buf.put_u8(*meta_type as u8);
+                    buf.put_slice(hash);
+                }
+            }
+            Message::SendMeta { meta_type, meta_hash, body } => {
+                buf.put_u8(*meta_type as u8);
+                buf.put_slice(meta_hash);
+                buf.put_u32_le(body.len() as u32);
+                buf.put_slice(body);
+            }
+            Message::MetaOk => {
+                // No payload
+            }
+            Message::MetaFail { reason } => {
+                let reason_bytes = reason.as_bytes();
+                buf.put_u16_le(reason_bytes.len() as u16);
+                buf.put_slice(reason_bytes);
+            }
+            Message::SendSnapshot { snapshot_hash, body } => {
+                buf.put_slice(snapshot_hash);
+                buf.put_u32_le(body.len() as u32);
+                buf.put_slice(body);
+            }
+            Message::SnapshotOk { snapshot_id } => {
+                let id_bytes = snapshot_id.as_bytes();
+                buf.put_u16_le(id_bytes.len() as u16);
+                buf.put_slice(id_bytes);
+            }
+            Message::SnapshotFail { missing_chunks, missing_metas } => {
+                buf.put_u32_le(missing_chunks.len() as u32);
+                for hash in missing_chunks {
+                    buf.put_slice(hash);
+                }
+                buf.put_u32_le(missing_metas.len() as u32);
+                for (meta_type, hash) in missing_metas {
+                    buf.put_u8(*meta_type as u8);
+                    buf.put_slice(hash);
+                }
+            }
+            Message::Close => {
+                // No payload
+            }
+        }
+
+        Ok(buf.freeze())
+    }
+
+    /// Deserialize message payload from bytes
+    pub fn deserialize_payload(cmd: Command, mut payload: Bytes) -> Result<Self> {
+        match cmd {
+            Command::Hello => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "Hello payload too short"));
+                }
+                let client_type = payload.get_u8();
+                let auth_type = payload.get_u8();
+                Ok(Message::Hello { client_type, auth_type })
+            }
+            Command::HelloOk => Ok(Message::HelloOk),
+            Command::AuthUserPass => {
+                if payload.remaining() < 12 { // 4 bytes for lengths + at least 8 bytes for machine_id
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthUserPass payload too short"));
+                }
+                let username_len = payload.get_u16_le() as usize;
+                if payload.remaining() < username_len + 10 { // 2 bytes for password len + 8 bytes for machine_id
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthUserPass username too short"));
+                }
+                let username = String::from_utf8(payload.copy_to_bytes(username_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in username"))?;
+                let password_len = payload.get_u16_le() as usize;
+                if payload.remaining() < password_len + 8 { // 8 bytes for machine_id
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthUserPass password too short"));
+                }
+                let password = String::from_utf8(payload.copy_to_bytes(password_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in password"))?;
+                let machine_id = payload.get_i64_le();
+                Ok(Message::AuthUserPass { username, password, machine_id })
+            }
+            Command::AuthCode => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthCode payload too short"));
+                }
+                let code_len = payload.get_u16_le() as usize;
+                if payload.remaining() < code_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthCode code too short"));
+                }
+                let code = String::from_utf8(payload.copy_to_bytes(code_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in code"))?;
+                Ok(Message::AuthCode { code })
+            }
+            Command::AuthOk => {
+                if payload.remaining() < 16 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthOk payload too short"));
+                }
+                let mut session_id = [0u8; 16];
+                payload.copy_to_slice(&mut session_id);
+                Ok(Message::AuthOk { session_id })
+            }
+            Command::AuthFail => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthFail payload too short"));
+                }
+                let reason_len = payload.get_u16_le() as usize;
+                if payload.remaining() < reason_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "AuthFail reason too short"));
+                }
+                let reason = String::from_utf8(payload.copy_to_bytes(reason_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in reason"))?;
+                Ok(Message::AuthFail { reason })
+            }
+            Command::BatchCheckChunk => {
+                if payload.remaining() < 4 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "BatchCheckChunk payload too short"));
+                }
+                let count = payload.get_u32_le() as usize;
+                if payload.remaining() < count * 32 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "BatchCheckChunk hashes too short"));
+                }
+                let mut hashes = Vec::with_capacity(count);
+                for _ in 0..count {
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    hashes.push(hash);
+                }
+                Ok(Message::BatchCheckChunk { hashes })
+            }
+            Command::CheckChunkResp => {
+                if payload.remaining() < 4 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "CheckChunkResp payload too short"));
+                }
+                let count = payload.get_u32_le() as usize;
+                if payload.remaining() < count * 32 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "CheckChunkResp hashes too short"));
+                }
+                let mut missing_hashes = Vec::with_capacity(count);
+                for _ in 0..count {
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    missing_hashes.push(hash);
+                }
+                Ok(Message::CheckChunkResp { missing_hashes })
+            }
+            Command::SendChunk => {
+                if payload.remaining() < 36 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendChunk payload too short"));
+                }
+                let mut hash = [0u8; 32];
+                payload.copy_to_slice(&mut hash);
+                let size = payload.get_u32_le() as usize;
+                if payload.remaining() < size {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendChunk data too short"));
+                }
+                let data = payload.copy_to_bytes(size);
+                Ok(Message::SendChunk { hash, data })
+            }
+            Command::ChunkOk => Ok(Message::ChunkOk),
+            Command::ChunkFail => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "ChunkFail payload too short"));
+                }
+                let reason_len = payload.get_u16_le() as usize;
+                if payload.remaining() < reason_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "ChunkFail reason too short"));
+                }
+                let reason = String::from_utf8(payload.copy_to_bytes(reason_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in reason"))?;
+                Ok(Message::ChunkFail { reason })
+            }
+            Command::BatchCheckMeta => {
+                if payload.remaining() < 4 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "BatchCheckMeta payload too short"));
+                }
+                let count = payload.get_u32_le() as usize;
+                if payload.remaining() < count * 33 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "BatchCheckMeta items too short"));
+                }
+                let mut items = Vec::with_capacity(count);
+                for _ in 0..count {
+                    let meta_type = MetaType::try_from(payload.get_u8())?;
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    items.push((meta_type, hash));
+                }
+                Ok(Message::BatchCheckMeta { items })
+            }
+            Command::CheckMetaResp => {
+                if payload.remaining() < 4 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "CheckMetaResp payload too short"));
+                }
+                let count = payload.get_u32_le() as usize;
+                if payload.remaining() < count * 33 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "CheckMetaResp items too short"));
+                }
+                let mut missing_items = Vec::with_capacity(count);
+                for _ in 0..count {
+                    let meta_type = MetaType::try_from(payload.get_u8())?;
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    missing_items.push((meta_type, hash));
+                }
+                Ok(Message::CheckMetaResp { missing_items })
+            }
+            Command::SendMeta => {
+                if payload.remaining() < 37 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendMeta payload too short"));
+                }
+                let meta_type = MetaType::try_from(payload.get_u8())?;
+                let mut meta_hash = [0u8; 32];
+                payload.copy_to_slice(&mut meta_hash);
+                let body_len = payload.get_u32_le() as usize;
+                if payload.remaining() < body_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendMeta body too short"));
+                }
+                let body = payload.copy_to_bytes(body_len);
+                Ok(Message::SendMeta { meta_type, meta_hash, body })
+            }
+            Command::MetaOk => Ok(Message::MetaOk),
+            Command::MetaFail => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "MetaFail payload too short"));
+                }
+                let reason_len = payload.get_u16_le() as usize;
+                if payload.remaining() < reason_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "MetaFail reason too short"));
+                }
+                let reason = String::from_utf8(payload.copy_to_bytes(reason_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in reason"))?;
+                Ok(Message::MetaFail { reason })
+            }
+            Command::SendSnapshot => {
+                if payload.remaining() < 36 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendSnapshot payload too short"));
+                }
+                let mut snapshot_hash = [0u8; 32];
+                payload.copy_to_slice(&mut snapshot_hash);
+                let body_len = payload.get_u32_le() as usize;
+                if payload.remaining() < body_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SendSnapshot body too short"));
+                }
+                let body = payload.copy_to_bytes(body_len);
+                Ok(Message::SendSnapshot { snapshot_hash, body })
+            }
+            Command::SnapshotOk => {
+                if payload.remaining() < 2 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotOk payload too short"));
+                }
+                let id_len = payload.get_u16_le() as usize;
+                if payload.remaining() < id_len {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotOk id too short"));
+                }
+                let snapshot_id = String::from_utf8(payload.copy_to_bytes(id_len).to_vec())
+                    .map_err(|_| Error::new(ErrorKind::InvalidData, "Invalid UTF-8 in snapshot_id"))?;
+                Ok(Message::SnapshotOk { snapshot_id })
+            }
+            Command::SnapshotFail => {
+                if payload.remaining() < 8 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotFail payload too short"));
+                }
+                let chunk_count = payload.get_u32_le() as usize;
+                if payload.remaining() < chunk_count * 32 + 4 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotFail chunks too short"));
+                }
+                let mut missing_chunks = Vec::with_capacity(chunk_count);
+                for _ in 0..chunk_count {
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    missing_chunks.push(hash);
+                }
+                let meta_count = payload.get_u32_le() as usize;
+                if payload.remaining() < meta_count * 33 {
+                    return Err(Error::new(ErrorKind::UnexpectedEof, "SnapshotFail metas too short"));
+                }
+                let mut missing_metas = Vec::with_capacity(meta_count);
+                for _ in 0..meta_count {
+                    let meta_type = MetaType::try_from(payload.get_u8())?;
+                    let mut hash = [0u8; 32];
+                    payload.copy_to_slice(&mut hash);
+                    missing_metas.push((meta_type, hash));
+                }
+                Ok(Message::SnapshotFail { missing_chunks, missing_metas })
+            }
+            Command::Close => Ok(Message::Close),
+        }
+    }
+
+    /// Get the command for this message
+    pub fn command(&self) -> Command {
+        match self {
+            Message::Hello { .. } => Command::Hello,
+            Message::HelloOk => Command::HelloOk,
+            Message::AuthUserPass { .. } => Command::AuthUserPass,
+            Message::AuthCode { .. } => Command::AuthCode,
+            Message::AuthOk { .. } => Command::AuthOk,
+            Message::AuthFail { .. } => Command::AuthFail,
+            Message::BatchCheckChunk { .. } => Command::BatchCheckChunk,
+            Message::CheckChunkResp { .. } => Command::CheckChunkResp,
+            Message::SendChunk { .. } => Command::SendChunk,
+            Message::ChunkOk => Command::ChunkOk,
+            Message::ChunkFail { .. } => Command::ChunkFail,
+            Message::BatchCheckMeta { .. } => Command::BatchCheckMeta,
+            Message::CheckMetaResp { .. } => Command::CheckMetaResp,
+            Message::SendMeta { .. } => Command::SendMeta,
+            Message::MetaOk => Command::MetaOk,
+            Message::MetaFail { .. } => Command::MetaFail,
+            Message::SendSnapshot { .. } => Command::SendSnapshot,
+            Message::SnapshotOk { .. } => Command::SnapshotOk,
+            Message::SnapshotFail { .. } => Command::SnapshotFail,
+            Message::Close => Command::Close,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_header_serialization() {
+        let header = MessageHeader::new(Command::Hello, [1; 16], 42);
+        let serialized = header.serialize();
+        let deserialized = MessageHeader::deserialize(&serialized).unwrap();
+        
+        assert_eq!(deserialized.cmd, Command::Hello);
+        assert_eq!(deserialized.session_id, [1; 16]);
+        assert_eq!(deserialized.payload_len, 42);
+    }
+
+    #[test]
+    fn test_hello_message() {
+        let msg = Message::Hello { client_type: 1, auth_type: 2 };
+        let payload = msg.serialize_payload().unwrap();
+        let deserialized = Message::deserialize_payload(Command::Hello, payload).unwrap();
+        
+        match deserialized {
+            Message::Hello { client_type, auth_type } => {
+                assert_eq!(client_type, 1);
+                assert_eq!(auth_type, 2);
+            }
+            _ => panic!("Wrong message type"),
+        }
+    }
+}

server/src/sync/server.rs

@@ -0,0 +1,462 @@
+use anyhow::{Context, Result};
+use bytes::Bytes;
+use sqlx::SqlitePool;
+use std::sync::Arc;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::{TcpListener, TcpStream};
+use uuid::Uuid;
+
+use crate::sync::protocol::{Command, Message, MessageHeader, MetaType};
+use crate::sync::session::{SessionManager, session_cleanup_task};
+use crate::sync::storage::Storage;
+use crate::sync::validation::SnapshotValidator;
+
+/// Configuration for the sync server
+#[derive(Debug, Clone)]
+pub struct SyncServerConfig {
+    pub bind_address: String,
+    pub port: u16,
+    pub data_dir: String,
+    pub max_connections: usize,
+    pub chunk_size_limit: usize,
+    pub meta_size_limit: usize,
+    pub batch_limit: usize,
+}
+
+impl Default for SyncServerConfig {
+    fn default() -> Self {
+        Self {
+            bind_address: "0.0.0.0".to_string(),
+            port: 8380,
+            data_dir: "./data".to_string(),
+            max_connections: 100,
+            chunk_size_limit: 4 * 1024 * 1024, // 4 MiB
+            meta_size_limit: 1024 * 1024,      // 1 MiB
+            batch_limit: 1000,
+        }
+    }
+}
+
+/// Main sync server
+pub struct SyncServer {
+    config: SyncServerConfig,
+    storage: Storage,
+    session_manager: Arc<SessionManager>,
+    validator: SnapshotValidator,
+}
+
+impl SyncServer {
+    pub fn new(config: SyncServerConfig, db_pool: SqlitePool) -> Self {
+        let storage = Storage::new(&config.data_dir);
+        let session_manager = Arc::new(SessionManager::new(db_pool));
+        let validator = SnapshotValidator::new(storage.clone());
+
+        Self {
+            config,
+            storage,
+            session_manager,
+            validator,
+        }
+    }
+
+    /// Start the sync server
+    pub async fn start(&self) -> Result<()> {
+        // Initialize storage
+        self.storage.init().await
+            .context("Failed to initialize storage")?;
+
+        let bind_addr = format!("{}:{}", self.config.bind_address, self.config.port);
+        let listener = TcpListener::bind(&bind_addr).await
+            .with_context(|| format!("Failed to bind to {}", bind_addr))?;
+
+        println!("Sync server listening on {}", bind_addr);
+
+        // Start session cleanup task
+        let session_manager_clone = Arc::clone(&self.session_manager);
+        tokio::spawn(async move {
+            session_cleanup_task(session_manager_clone).await;
+        });
+
+        // Accept connections
+        loop {
+            match listener.accept().await {
+                Ok((stream, addr)) => {
+                    println!("New sync connection from {}", addr);
+                    
+                    let handler = ConnectionHandler::new(
+                        stream,
+                        self.storage.clone(),
+                        Arc::clone(&self.session_manager),
+                        self.validator.clone(),
+                        self.config.clone(),
+                    );
+
+                    tokio::spawn(async move {
+                        if let Err(e) = handler.handle().await {
+                            eprintln!("Connection error from {}: {}", addr, e);
+                        }
+                    });
+                }
+                Err(e) => {
+                    eprintln!("Failed to accept connection: {}", e);
+                }
+            }
+        }
+    }
+}
+
+/// Connection handler for individual sync clients
+struct ConnectionHandler {
+    stream: TcpStream,
+    storage: Storage,
+    session_manager: Arc<SessionManager>,
+    validator: SnapshotValidator,
+    config: SyncServerConfig,
+    session_id: Option<[u8; 16]>,
+    machine_id: Option<i64>,
+}
+
+impl ConnectionHandler {
+    fn new(
+        stream: TcpStream,
+        storage: Storage,
+        session_manager: Arc<SessionManager>,
+        validator: SnapshotValidator,
+        config: SyncServerConfig,
+    ) -> Self {
+        Self {
+            stream,
+            storage,
+            session_manager,
+            validator,
+            config,
+            session_id: None,
+            machine_id: None,
+        }
+    }
+
+    /// Handle the connection
+    async fn handle(mut self) -> Result<()> {
+        loop {
+            // Read message header
+            let header = self.read_header().await?;
+            
+            // Read payload
+            let payload = if header.payload_len > 0 {
+                self.read_payload(header.payload_len).await?
+            } else {
+                Bytes::new()
+            };
+
+            // Parse message
+            let message = Message::deserialize_payload(header.cmd, payload)
+                .context("Failed to deserialize message")?;
+
+            // Handle message
+            let response = self.handle_message(message).await?;
+            
+            // Send response
+            if let Some(response_msg) = response {
+                self.send_message(response_msg).await?;
+            }
+
+            // Close connection if requested
+            if header.cmd == Command::Close {
+                break;
+            }
+        }
+
+        // Clean up session
+        if let Some(session_id) = self.session_id {
+            self.session_manager.remove_session(&session_id).await;
+        }
+
+        Ok(())
+    }
+
+    /// Read message header
+    async fn read_header(&mut self) -> Result<MessageHeader> {
+        let mut header_buf = [0u8; MessageHeader::SIZE];
+        self.stream.read_exact(&mut header_buf).await
+            .context("Failed to read message header")?;
+        
+        MessageHeader::deserialize(&header_buf)
+            .context("Failed to parse message header")
+    }
+
+    /// Read message payload
+    async fn read_payload(&mut self, len: u32) -> Result<Bytes> {
+        if len as usize > self.config.meta_size_limit {
+            return Err(anyhow::anyhow!("Payload too large: {} bytes", len));
+        }
+
+        let mut payload_buf = vec![0u8; len as usize];
+        self.stream.read_exact(&mut payload_buf).await
+            .context("Failed to read message payload")?;
+        
+        Ok(Bytes::from(payload_buf))
+    }
+
+    /// Send a message
+    async fn send_message(&mut self, message: Message) -> Result<()> {
+        let session_id = self.session_id.unwrap_or([0u8; 16]);
+        let payload = message.serialize_payload()?;
+        
+        let header = MessageHeader::new(message.command(), session_id, payload.len() as u32);
+        let header_bytes = header.serialize();
+
+        self.stream.write_all(&header_bytes).await
+            .context("Failed to write message header")?;
+        
+        if !payload.is_empty() {
+            self.stream.write_all(&payload).await
+                .context("Failed to write message payload")?;
+        }
+
+        self.stream.flush().await
+            .context("Failed to flush stream")?;
+
+        Ok(())
+    }
+
+    /// Handle a received message
+    async fn handle_message(&mut self, message: Message) -> Result<Option<Message>> {
+        match message {
+            Message::Hello { client_type: _, auth_type: _ } => {
+                Ok(Some(Message::HelloOk))
+            }
+
+            Message::AuthUserPass { username, password, machine_id } => {
+                match self.session_manager.authenticate_userpass(&username, &password, machine_id).await {
+                    Ok(session) => {
+                        self.session_id = Some(session.session_id);
+                        self.machine_id = Some(session.machine_id);
+                        Ok(Some(Message::AuthOk { session_id: session.session_id }))
+                    }
+                    Err(e) => {
+                        Ok(Some(Message::AuthFail { reason: e.to_string() }))
+                    }
+                }
+            }
+
+            Message::AuthCode { code } => {
+                match self.session_manager.authenticate_code(&code).await {
+                    Ok(session) => {
+                        self.session_id = Some(session.session_id);
+                        self.machine_id = Some(session.machine_id);
+                        Ok(Some(Message::AuthOk { session_id: session.session_id }))
+                    }
+                    Err(e) => {
+                        Ok(Some(Message::AuthFail { reason: e.to_string() }))
+                    }
+                }
+            }
+
+            Message::BatchCheckChunk { hashes } => {
+                self.require_auth()?;
+                
+                if hashes.len() > self.config.batch_limit {
+                    return Err(anyhow::anyhow!("Batch size exceeds limit: {}", hashes.len()));
+                }
+
+                let missing_hashes = self.validator.validate_chunk_batch(&hashes).await?;
+                Ok(Some(Message::CheckChunkResp { missing_hashes }))
+            }
+
+            Message::SendChunk { hash, data } => {
+                self.require_auth()?;
+                
+                if data.len() > self.config.chunk_size_limit {
+                    return Ok(Some(Message::ChunkFail { 
+                        reason: format!("Chunk too large: {} bytes", data.len()) 
+                    }));
+                }
+
+                match self.storage.store_chunk(&hash, &data).await {
+                    Ok(()) => Ok(Some(Message::ChunkOk)),
+                    Err(e) => Ok(Some(Message::ChunkFail { reason: e.to_string() })),
+                }
+            }
+
+            Message::BatchCheckMeta { items } => {
+                self.require_auth()?;
+                
+                if items.len() > self.config.batch_limit {
+                    return Err(anyhow::anyhow!("Batch size exceeds limit: {}", items.len()));
+                }
+
+                let missing_items = self.validator.validate_meta_batch(&items).await?;
+                Ok(Some(Message::CheckMetaResp { missing_items }))
+            }
+
+            Message::SendMeta { meta_type, meta_hash, body } => {
+                self.require_auth()?;
+                
+                if body.len() > self.config.meta_size_limit {
+                    return Ok(Some(Message::MetaFail { 
+                        reason: format!("Meta object too large: {} bytes", body.len()) 
+                    }));
+                }
+
+                match self.storage.store_meta(meta_type, &meta_hash, &body).await {
+                    Ok(()) => Ok(Some(Message::MetaOk)),
+                    Err(e) => Ok(Some(Message::MetaFail { reason: e.to_string() })),
+                }
+            }
+
+            Message::SendSnapshot { snapshot_hash, body } => {
+                self.require_auth()?;
+                
+                if body.len() > self.config.meta_size_limit {
+                    println!("Snapshot rejected: size limit exceeded ({} > {})", body.len(), self.config.meta_size_limit);
+                    return Ok(Some(Message::SnapshotFail { 
+                        missing_chunks: vec![],
+                        missing_metas: vec![],
+                    }));
+                }
+
+                println!("Validating snapshot hash: {}", hex::encode(&snapshot_hash));
+
+                // Validate snapshot
+                match self.validator.validate_snapshot(&snapshot_hash, &body).await {
+                    Ok(validation_result) => {
+                        println!("Validation result - is_valid: {}, missing_chunks: {}, missing_metas: {}", 
+                                validation_result.is_valid, 
+                                validation_result.missing_chunks.len(), 
+                                validation_result.missing_metas.len());
+                        
+                        if validation_result.is_valid {
+                            // Store snapshot meta
+                            if let Err(e) = self.storage.store_meta(MetaType::Snapshot, &snapshot_hash, &body).await {
+                                println!("Failed to store snapshot meta: {}", e);
+                                return Ok(Some(Message::SnapshotFail { 
+                                    missing_chunks: vec![],
+                                    missing_metas: vec![],
+                                }));
+                            }
+
+                            // Create snapshot reference
+                            let snapshot_id = Uuid::new_v4().to_string();
+                            let machine_id = *self.machine_id.as_ref().unwrap();
+                            let created_at = chrono::Utc::now().timestamp() as u64;
+
+                            println!("Creating snapshot reference: machine_id={}, snapshot_id={}", machine_id, snapshot_id);
+
+                            if let Err(e) = self.storage.store_snapshot_ref(
+                                machine_id, 
+                                &snapshot_id, 
+                                &snapshot_hash, 
+                                created_at
+                            ).await {
+                                println!("Failed to store snapshot reference: {}", e);
+                                return Ok(Some(Message::SnapshotFail { 
+                                    missing_chunks: vec![],
+                                    missing_metas: vec![],
+                                }));
+                            }
+
+                            println!("Snapshot successfully stored with ID: {}", snapshot_id);
+                            Ok(Some(Message::SnapshotOk { snapshot_id }))
+                        } else {
+                            println!("Snapshot validation failed - returning missing items");
+                            Ok(Some(Message::SnapshotFail {
+                                missing_chunks: validation_result.missing_chunks,
+                                missing_metas: validation_result.missing_metas,
+                            }))
+                        }
+                    }
+                    Err(e) => {
+                        println!("Snapshot validation error: {}", e);
+                        Ok(Some(Message::SnapshotFail { 
+                            missing_chunks: vec![],
+                            missing_metas: vec![],
+                        }))
+                    }
+                }
+            }
+
+            Message::Close => {
+                Ok(None) // No response needed
+            }
+
+            // These are response messages that shouldn't be received by the server
+            Message::HelloOk | Message::AuthOk { .. } | Message::AuthFail { .. } |
+            Message::CheckChunkResp { .. } | Message::ChunkOk | Message::ChunkFail { .. } |
+            Message::CheckMetaResp { .. } | Message::MetaOk | Message::MetaFail { .. } |
+            Message::SnapshotOk { .. } | Message::SnapshotFail { .. } => {
+                Err(anyhow::anyhow!("Unexpected response message from client"))
+            }
+        }
+    }
+
+    /// Require authentication for protected operations
+    fn require_auth(&self) -> Result<()> {
+        if self.session_id.is_none() {
+            return Err(anyhow::anyhow!("Authentication required"));
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+    use sqlx::sqlite::SqlitePoolOptions;
+
+    async fn setup_test_server() -> (SyncServer, TempDir) {
+        let temp_dir = TempDir::new().unwrap();
+        
+        let pool = SqlitePoolOptions::new()
+            .connect(":memory:")
+            .await
+            .unwrap();
+
+        // Create required tables
+        sqlx::query!(
+            r#"
+            CREATE TABLE users (
+                id INTEGER PRIMARY KEY,
+                username TEXT UNIQUE NOT NULL,
+                password_hash TEXT NOT NULL,
+                active INTEGER DEFAULT 1
+            )
+            "#
+        )
+        .execute(&pool)
+        .await
+        .unwrap();
+
+        sqlx::query!(
+            r#"
+            CREATE TABLE provisioning_codes (
+                id INTEGER PRIMARY KEY,
+                code TEXT UNIQUE NOT NULL,
+                created_by INTEGER NOT NULL,
+                expires_at TEXT NOT NULL,
+                used INTEGER DEFAULT 0,
+                used_at TEXT,
+                FOREIGN KEY (created_by) REFERENCES users (id)
+            )
+            "#
+        )
+        .execute(&pool)
+        .await
+        .unwrap();
+
+        let config = SyncServerConfig {
+            data_dir: temp_dir.path().to_string_lossy().to_string(),
+            ..Default::default()
+        };
+
+        (SyncServer::new(config, pool), temp_dir)
+    }
+
+    #[tokio::test]
+    async fn test_server_creation() {
+        let (server, _temp_dir) = setup_test_server().await;
+        
+        // Initialize storage to verify everything works
+        server.storage.init().await.unwrap();
+    }
+}

server/src/sync/session.rs

@@ -0,0 +1,343 @@
+use anyhow::{Context, Result};
+use rand::RngCore;
+use sqlx::SqlitePool;
+use std::collections::HashMap;
+use std::sync::Arc;
+use tokio::sync::RwLock;
+
+/// Session information
+#[derive(Debug, Clone)]
+pub struct Session {
+    pub session_id: [u8; 16],
+    pub machine_id: i64,
+    pub user_id: i64,
+    pub created_at: chrono::DateTime<chrono::Utc>,
+}
+
+/// Session manager for sync connections
+#[derive(Debug)]
+pub struct SessionManager {
+    sessions: Arc<RwLock<HashMap<[u8; 16], Session>>>,
+    db_pool: SqlitePool,
+}
+
+impl SessionManager {
+    pub fn new(db_pool: SqlitePool) -> Self {
+        Self {
+            sessions: Arc::new(RwLock::new(HashMap::new())),
+            db_pool,
+        }
+    }
+
+    /// Get database pool reference
+    pub fn get_db_pool(&self) -> &SqlitePool {
+        &self.db_pool
+    }
+
+    /// Generate a new session ID
+    fn generate_session_id() -> [u8; 16] {
+        let mut session_id = [0u8; 16];
+        rand::thread_rng().fill_bytes(&mut session_id);
+        session_id
+    }
+
+    /// Authenticate with username/password and validate machine ownership
+    pub async fn authenticate_userpass(&self, username: &str, password: &str, machine_id: i64) -> Result<Session> {
+        // Query user from database
+        let user = sqlx::query!(
+            "SELECT id, username, password_hash FROM users WHERE username = ?",
+            username
+        )
+        .fetch_optional(&self.db_pool)
+        .await
+        .context("Failed to query user")?;
+
+        let user = user.ok_or_else(|| anyhow::anyhow!("Invalid credentials"))?;
+
+        // Verify password
+        if !bcrypt::verify(password, &user.password_hash)
+            .context("Failed to verify password")? {
+            return Err(anyhow::anyhow!("Invalid credentials"));
+        }
+
+        let user_id = user.id.unwrap_or(0) as i64;
+
+        // Validate machine ownership
+        let machine = sqlx::query!(
+            "SELECT id, user_id FROM machines WHERE id = ?",
+            machine_id
+        )
+        .fetch_optional(&self.db_pool)
+        .await
+        .context("Failed to query machine")?;
+
+        let machine = machine.ok_or_else(|| anyhow::anyhow!("Machine not found"))?;
+        
+        let machine_user_id = machine.user_id;
+        if machine_user_id != user_id {
+            return Err(anyhow::anyhow!("Machine does not belong to user"));
+        }
+
+        // Create session with machine ID
+        let session_id = Self::generate_session_id();
+        let machine_id = machine.id; // Use database ID
+        let session = Session {
+            session_id,
+            machine_id,
+            user_id,
+            created_at: chrono::Utc::now(),
+        };
+
+        // Store session
+        let mut sessions = self.sessions.write().await;
+        sessions.insert(session_id, session.clone());
+
+        Ok(session)
+    }
+
+    /// Authenticate with provisioning code
+    pub async fn authenticate_code(&self, code: &str) -> Result<Session> {
+        // Query provisioning code from database
+        let provisioning_code = sqlx::query!(
+            r#"
+            SELECT pc.id, pc.code, pc.expires_at, pc.used, m.id as machine_id, m.user_id, u.username
+            FROM provisioning_codes pc
+            JOIN machines m ON pc.machine_id = m.id
+            JOIN users u ON m.user_id = u.id
+            WHERE pc.code = ? AND pc.used = 0
+            "#,
+            code
+        )
+        .fetch_optional(&self.db_pool)
+        .await
+        .context("Failed to query provisioning code")?;
+
+        let provisioning_code = provisioning_code
+            .ok_or_else(|| anyhow::anyhow!("Invalid or used provisioning code"))?;
+
+        // Check if code is expired
+        let expires_at: chrono::DateTime<chrono::Utc> = chrono::DateTime::from_naive_utc_and_offset(
+            provisioning_code.expires_at, 
+            chrono::Utc
+        );
+
+        if chrono::Utc::now() > expires_at {
+            return Err(anyhow::anyhow!("Provisioning code expired"));
+        }
+
+        // Mark code as used
+        sqlx::query!(
+            "UPDATE provisioning_codes SET used = 1 WHERE id = ?",
+            provisioning_code.id
+        )
+        .execute(&self.db_pool)
+        .await
+        .context("Failed to mark provisioning code as used")?;
+
+        // Create session
+        let session_id = Self::generate_session_id();
+        let machine_id = provisioning_code.machine_id.expect("Machine ID should not be null"); // Use machine ID from database
+        let session = Session {
+            session_id,
+            machine_id,
+            user_id: provisioning_code.user_id as i64,
+            created_at: chrono::Utc::now(),
+        };
+
+        // Store session
+        let mut sessions = self.sessions.write().await;
+        sessions.insert(session_id, session.clone());
+
+        Ok(session)
+    }
+
+    /// Get session by session ID
+    pub async fn get_session(&self, session_id: &[u8; 16]) -> Option<Session> {
+        let sessions = self.sessions.read().await;
+        sessions.get(session_id).cloned()
+    }
+
+    /// Validate session and return associated machine ID
+    pub async fn validate_session(&self, session_id: &[u8; 16]) -> Result<i64> {
+        let session = self.get_session(session_id).await
+            .ok_or_else(|| anyhow::anyhow!("Invalid session"))?;
+
+        // Check if session is too old (24 hours)
+        let session_age = chrono::Utc::now() - session.created_at;
+        if session_age > chrono::Duration::hours(24) {
+            // Remove expired session
+            let mut sessions = self.sessions.write().await;
+            sessions.remove(session_id);
+            return Err(anyhow::anyhow!("Session expired"));
+        }
+
+        Ok(session.machine_id)
+    }
+
+    /// Remove session
+    pub async fn remove_session(&self, session_id: &[u8; 16]) {
+        let mut sessions = self.sessions.write().await;
+        sessions.remove(session_id);
+    }
+
+    /// Clean up expired sessions
+    pub async fn cleanup_expired_sessions(&self) {
+        let mut sessions = self.sessions.write().await;
+        let now = chrono::Utc::now();
+        
+        sessions.retain(|_, session| {
+            let age = now - session.created_at;
+            age <= chrono::Duration::hours(24)
+        });
+    }
+
+    /// Get active session count
+    pub async fn active_session_count(&self) -> usize {
+        let sessions = self.sessions.read().await;
+        sessions.len()
+    }
+
+    /// List active sessions
+    pub async fn list_active_sessions(&self) -> Vec<Session> {
+        let sessions = self.sessions.read().await;
+        sessions.values().cloned().collect()
+    }
+}
+
+/// Periodic cleanup task for expired sessions
+pub async fn session_cleanup_task(session_manager: Arc<SessionManager>) {
+    let mut interval = tokio::time::interval(tokio::time::Duration::from_secs(3600)); // Every hour
+    
+    loop {
+        interval.tick().await;
+        session_manager.cleanup_expired_sessions().await;
+        println!("Cleaned up expired sync sessions. Active sessions: {}", 
+                session_manager.active_session_count().await);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sqlx::sqlite::SqlitePoolOptions;
+
+    async fn setup_test_db() -> SqlitePool {
+        let pool = SqlitePoolOptions::new()
+            .connect(":memory:")
+            .await
+            .unwrap();
+
+        // Create tables
+        sqlx::query!(
+            r#"
+            CREATE TABLE users (
+                id INTEGER PRIMARY KEY,
+                username TEXT UNIQUE NOT NULL,
+                password_hash TEXT NOT NULL,
+                active INTEGER DEFAULT 1
+            )
+            "#
+        )
+        .execute(&pool)
+        .await
+        .unwrap();
+
+        sqlx::query!(
+            r#"
+            CREATE TABLE provisioning_codes (
+                id INTEGER PRIMARY KEY,
+                code TEXT UNIQUE NOT NULL,
+                created_by INTEGER NOT NULL,
+                expires_at TEXT NOT NULL,
+                used INTEGER DEFAULT 0,
+                used_at TEXT,
+                FOREIGN KEY (created_by) REFERENCES users (id)
+            )
+            "#
+        )
+        .execute(&pool)
+        .await
+        .unwrap();
+
+        // Insert test user
+        let password_hash = bcrypt::hash("password123", bcrypt::DEFAULT_COST).unwrap();
+        sqlx::query!(
+            "INSERT INTO users (username, password_hash) VALUES (?, ?)",
+            "testuser",
+            password_hash
+        )
+        .execute(&pool)
+        .await
+        .unwrap();
+
+        pool
+    }
+
+    #[tokio::test]
+    async fn test_authenticate_userpass() {
+        let pool = setup_test_db().await;
+        let session_manager = SessionManager::new(pool);
+
+        let session = session_manager
+            .authenticate_userpass("testuser", "password123")
+            .await
+            .unwrap();
+
+        assert_eq!(session.user_id, 1);
+        assert!(!session.machine_id.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_authenticate_userpass_invalid() {
+        let pool = setup_test_db().await;
+        let session_manager = SessionManager::new(pool);
+
+        let result = session_manager
+            .authenticate_userpass("testuser", "wrongpassword")
+            .await;
+
+        assert!(result.is_err());
+    }
+
+    #[tokio::test]
+    async fn test_session_validation() {
+        let pool = setup_test_db().await;
+        let session_manager = SessionManager::new(pool);
+
+        let session = session_manager
+            .authenticate_userpass("testuser", "password123")
+            .await
+            .unwrap();
+
+        let machine_id = session_manager
+            .validate_session(&session.session_id)
+            .await
+            .unwrap();
+
+        assert_eq!(machine_id, session.machine_id);
+    }
+
+    #[tokio::test]
+    async fn test_session_cleanup() {
+        let pool = setup_test_db().await;
+        let session_manager = SessionManager::new(pool);
+
+        let session = session_manager
+            .authenticate_userpass("testuser", "password123")
+            .await
+            .unwrap();
+
+        assert_eq!(session_manager.active_session_count().await, 1);
+
+        // Manually expire the session
+        {
+            let mut sessions = session_manager.sessions.write().await;
+            if let Some(mut session) = sessions.get_mut(&session.session_id) {
+                session.created_at = chrono::Utc::now() - chrono::Duration::hours(25);
+            }
+        }
+
+        session_manager.cleanup_expired_sessions().await;
+        assert_eq!(session_manager.active_session_count().await, 0);
+    }
+}

server/src/sync/storage.rs

@@ -0,0 +1,406 @@
+use anyhow::{Context, Result};
+use bytes::Bytes;
+use std::collections::HashSet;
+use std::path::{Path, PathBuf};
+use tokio::fs;
+use crate::sync::protocol::{Hash, MetaType};
+use crate::sync::meta::MetaObj;
+
+/// Storage backend for chunks and metadata objects
+#[derive(Debug, Clone)]
+pub struct Storage {
+    data_dir: PathBuf,
+}
+
+impl Storage {
+    pub fn new<P: AsRef<Path>>(data_dir: P) -> Self {
+        Self {
+            data_dir: data_dir.as_ref().to_path_buf(),
+        }
+    }
+
+    /// Initialize storage directories
+    pub async fn init(&self) -> Result<()> {
+        let chunks_dir = self.data_dir.join("sync").join("chunks");
+        let meta_dir = self.data_dir.join("sync").join("meta");
+        let machines_dir = self.data_dir.join("sync").join("machines");
+
+        fs::create_dir_all(&chunks_dir).await
+            .context("Failed to create chunks directory")?;
+        
+        fs::create_dir_all(&meta_dir).await
+            .context("Failed to create meta directory")?;
+
+        fs::create_dir_all(&machines_dir).await
+            .context("Failed to create machines directory")?;
+
+        // Create subdirectories for each meta type
+        for meta_type in &["files", "dirs", "partitions", "disks", "snapshots"] {
+            fs::create_dir_all(meta_dir.join(meta_type)).await
+                .with_context(|| format!("Failed to create meta/{} directory", meta_type))?;
+        }
+
+        Ok(())
+    }
+
+    /// Get chunk storage path for a hash
+    fn chunk_path(&self, hash: &Hash) -> PathBuf {
+        let hex = hex::encode(hash);
+        let ab = &hex[0..2];
+        let cd = &hex[2..4];
+        let filename = format!("{}.chk", hex);
+        
+        self.data_dir
+            .join("sync")
+            .join("chunks")
+            .join(ab)
+            .join(cd)
+            .join(filename)
+    }
+
+    /// Get meta storage path for a hash and type
+    fn meta_path(&self, meta_type: MetaType, hash: &Hash) -> PathBuf {
+        let hex = hex::encode(hash);
+        let ab = &hex[0..2];
+        let cd = &hex[2..4];
+        let filename = format!("{}.meta", hex);
+        
+        let type_dir = match meta_type {
+            MetaType::File => "files",
+            MetaType::Dir => "dirs", 
+            MetaType::Partition => "partitions",
+            MetaType::Disk => "disks",
+            MetaType::Snapshot => "snapshots",
+        };
+        
+        self.data_dir
+            .join("sync")
+            .join("meta")
+            .join(type_dir)
+            .join(ab)
+            .join(cd)
+            .join(filename)
+    }
+
+    /// Check if a chunk exists
+    pub async fn chunk_exists(&self, hash: &Hash) -> bool {
+        let path = self.chunk_path(hash);
+        path.exists()
+    }
+
+    /// Check if multiple chunks exist
+    pub async fn chunks_exist(&self, hashes: &[Hash]) -> Result<HashSet<Hash>> {
+        let mut existing = HashSet::new();
+        
+        for hash in hashes {
+            if self.chunk_exists(hash).await {
+                existing.insert(*hash);
+            }
+        }
+        
+        Ok(existing)
+    }
+
+    /// Store a chunk
+    pub async fn store_chunk(&self, hash: &Hash, data: &[u8]) -> Result<()> {
+        // Verify hash
+        let computed_hash = blake3::hash(data);
+        if computed_hash.as_bytes() != hash {
+            return Err(anyhow::anyhow!("Chunk hash mismatch"));
+        }
+
+        let path = self.chunk_path(hash);
+        
+        // Create parent directories
+        if let Some(parent) = path.parent() {
+            fs::create_dir_all(parent).await
+                .context("Failed to create chunk directory")?;
+        }
+
+        // Write to temporary file first, then rename (atomic write)
+        let temp_path = path.with_extension("tmp");
+        fs::write(&temp_path, data).await
+            .context("Failed to write chunk to temporary file")?;
+        
+        fs::rename(&temp_path, &path).await
+            .context("Failed to rename chunk file")?;
+
+        Ok(())
+    }
+
+    /// Load a chunk
+    pub async fn load_chunk(&self, hash: &Hash) -> Result<Option<Bytes>> {
+        let path = self.chunk_path(hash);
+        
+        if !path.exists() {
+            return Ok(None);
+        }
+
+        let data = fs::read(&path).await
+            .context("Failed to read chunk file")?;
+        
+        // Verify hash
+        let computed_hash = blake3::hash(&data);
+        if computed_hash.as_bytes() != hash {
+            return Err(anyhow::anyhow!("Stored chunk hash mismatch"));
+        }
+
+        Ok(Some(Bytes::from(data)))
+    }
+
+    /// Check if a meta object exists
+    pub async fn meta_exists(&self, meta_type: MetaType, hash: &Hash) -> bool {
+        let path = self.meta_path(meta_type, hash);
+        path.exists()
+    }
+
+    /// Check if multiple meta objects exist
+    pub async fn metas_exist(&self, items: &[(MetaType, Hash)]) -> Result<HashSet<(MetaType, Hash)>> {
+        let mut existing = HashSet::new();
+        
+        for &(meta_type, hash) in items {
+            if self.meta_exists(meta_type, &hash).await {
+                existing.insert((meta_type, hash));
+            }
+        }
+        
+        Ok(existing)
+    }
+
+    /// Store a meta object
+    pub async fn store_meta(&self, meta_type: MetaType, hash: &Hash, body: &[u8]) -> Result<()> {
+        // Verify hash
+        let computed_hash = blake3::hash(body);
+        if computed_hash.as_bytes() != hash {
+            return Err(anyhow::anyhow!("Meta object hash mismatch"));
+        }
+
+        let path = self.meta_path(meta_type, hash);
+        
+        // Create parent directories
+        if let Some(parent) = path.parent() {
+            fs::create_dir_all(parent).await
+                .context("Failed to create meta directory")?;
+        }
+
+        // Write to temporary file first, then rename (atomic write)
+        let temp_path = path.with_extension("tmp");
+        fs::write(&temp_path, body).await
+            .context("Failed to write meta to temporary file")?;
+        
+        fs::rename(&temp_path, &path).await
+            .context("Failed to rename meta file")?;
+
+        Ok(())
+    }
+
+    /// Load a meta object
+    pub async fn load_meta(&self, meta_type: MetaType, hash: &Hash) -> Result<Option<MetaObj>> {
+        let path = self.meta_path(meta_type, hash);
+        
+        if !path.exists() {
+            println!("Meta file does not exist: {:?}", path);
+            return Ok(None);
+        }
+
+        println!("Reading meta file: {:?}", path);
+        let data = fs::read(&path).await
+            .context("Failed to read meta file")?;
+        
+        println!("Read {} bytes from meta file", data.len());
+        
+        // Verify hash
+        let computed_hash = blake3::hash(&data);
+        if computed_hash.as_bytes() != hash {
+            println!("Hash mismatch: expected {}, got {}", hex::encode(hash), hex::encode(computed_hash.as_bytes()));
+            return Err(anyhow::anyhow!("Stored meta object hash mismatch"));
+        }
+
+        println!("Hash verified, deserializing {:?} object", meta_type);
+        let meta_obj = MetaObj::deserialize(meta_type, Bytes::from(data))
+            .context("Failed to deserialize meta object")?;
+
+        println!("Successfully deserialized meta object");
+        Ok(Some(meta_obj))
+    }
+
+    /// Get snapshot storage path for a machine
+    fn snapshot_ref_path(&self, machine_id: i64, snapshot_id: &str) -> PathBuf {
+        self.data_dir
+            .join("sync")
+            .join("machines")
+            .join(machine_id.to_string())
+            .join("snapshots")
+            .join(format!("{}.ref", snapshot_id))
+    }
+
+    /// Store a snapshot reference
+    pub async fn store_snapshot_ref(
+        &self, 
+        machine_id: i64, 
+        snapshot_id: &str, 
+        snapshot_hash: &Hash,
+        created_at: u64
+    ) -> Result<()> {
+        let path = self.snapshot_ref_path(machine_id, snapshot_id);
+        
+        // Create parent directories
+        if let Some(parent) = path.parent() {
+            fs::create_dir_all(parent).await
+                .context("Failed to create snapshot reference directory")?;
+        }
+
+        // Create snapshot reference content
+        let content = format!("{}:{}", hex::encode(snapshot_hash), created_at);
+        
+        // Write to temporary file first, then rename (atomic write)
+        let temp_path = path.with_extension("tmp");
+        fs::write(&temp_path, content).await
+            .context("Failed to write snapshot reference to temporary file")?;
+        
+        fs::rename(&temp_path, &path).await
+            .context("Failed to rename snapshot reference file")?;
+
+        Ok(())
+    }
+
+    /// Load a snapshot reference
+    pub async fn load_snapshot_ref(&self, machine_id: i64, snapshot_id: &str) -> Result<Option<(Hash, u64)>> {
+        let path = self.snapshot_ref_path(machine_id, snapshot_id);
+        
+        if !path.exists() {
+            return Ok(None);
+        }
+
+        let content = fs::read_to_string(&path).await
+            .context("Failed to read snapshot reference file")?;
+        
+        let parts: Vec<&str> = content.trim().split(':').collect();
+        if parts.len() != 2 {
+            return Err(anyhow::anyhow!("Invalid snapshot reference format"));
+        }
+
+        let snapshot_hash: Hash = hex::decode(parts[0])
+            .context("Failed to decode snapshot hash")?
+            .try_into()
+            .map_err(|_| anyhow::anyhow!("Invalid snapshot hash length"))?;
+        
+        let created_at: u64 = parts[1].parse()
+            .context("Failed to parse snapshot timestamp")?;
+
+        Ok(Some((snapshot_hash, created_at)))
+    }
+
+    /// List snapshots for a machine
+    pub async fn list_snapshots(&self, machine_id: i64) -> Result<Vec<String>> {
+        let snapshots_dir = self.data_dir
+            .join("sync")
+            .join("machines")
+            .join(machine_id.to_string())
+            .join("snapshots");
+
+        if !snapshots_dir.exists() {
+            return Ok(Vec::new());
+        }
+
+        let mut entries = fs::read_dir(&snapshots_dir).await
+            .context("Failed to read snapshots directory")?;
+
+        let mut snapshots = Vec::new();
+        while let Some(entry) = entries.next_entry().await
+            .context("Failed to read snapshot entry")? {
+            
+            if let Some(file_name) = entry.file_name().to_str() {
+                if file_name.ends_with(".ref") {
+                    let snapshot_id = file_name.trim_end_matches(".ref");
+                    snapshots.push(snapshot_id.to_string());
+                }
+            }
+        }
+
+        snapshots.sort();
+        Ok(snapshots)
+    }
+
+    /// Delete old snapshots, keeping only the latest N
+    pub async fn cleanup_snapshots(&self, machine_id: i64, keep_count: usize) -> Result<()> {
+        let mut snapshots = self.list_snapshots(machine_id).await?;
+        
+        if snapshots.len() <= keep_count {
+            return Ok(());
+        }
+
+        snapshots.sort();
+        snapshots.reverse(); // Most recent first
+        
+        // Delete older snapshots
+        for snapshot_id in snapshots.iter().skip(keep_count) {
+            let path = self.snapshot_ref_path(machine_id, snapshot_id);
+            if path.exists() {
+                fs::remove_file(&path).await
+                    .with_context(|| format!("Failed to delete snapshot {}", snapshot_id))?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+/// Add hex crate to dependencies
+use hex;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+
+    #[tokio::test]
+    async fn test_storage_init() {
+        let temp_dir = TempDir::new().unwrap();
+        let storage = Storage::new(temp_dir.path());
+        storage.init().await.unwrap();
+
+        assert!(temp_dir.path().join("sync/chunks").exists());
+        assert!(temp_dir.path().join("sync/meta/files").exists());
+        assert!(temp_dir.path().join("sync/machines").exists());
+    }
+
+    #[tokio::test]
+    async fn test_chunk_storage() {
+        let temp_dir = TempDir::new().unwrap();
+        let storage = Storage::new(temp_dir.path());
+        storage.init().await.unwrap();
+
+        let data = b"test chunk data";
+        let hash = blake3::hash(data).into();
+
+        // Store chunk
+        storage.store_chunk(&hash, data).await.unwrap();
+        assert!(storage.chunk_exists(&hash).await);
+
+        // Load chunk
+        let loaded = storage.load_chunk(&hash).await.unwrap().unwrap();
+        assert_eq!(loaded.as_ref(), data);
+    }
+
+    #[tokio::test]
+    async fn test_snapshot_ref_storage() {
+        let temp_dir = TempDir::new().unwrap();
+        let storage = Storage::new(temp_dir.path());
+        storage.init().await.unwrap();
+
+        let machine_id = 123i64;
+        let snapshot_id = "snapshot-001";
+        let snapshot_hash = [1u8; 32];
+        let created_at = 1234567890;
+
+        storage.store_snapshot_ref(machine_id, snapshot_id, &snapshot_hash, created_at)
+            .await.unwrap();
+
+        let loaded = storage.load_snapshot_ref(machine_id, snapshot_id)
+            .await.unwrap().unwrap();
+
+        assert_eq!(loaded.0, snapshot_hash);
+        assert_eq!(loaded.1, created_at);
+    }
+}

server/src/sync/validation.rs

@@ -0,0 +1,235 @@
+use anyhow::{Context, Result};
+use std::collections::{HashSet, VecDeque};
+use crate::sync::protocol::{Hash, MetaType};
+use crate::sync::storage::Storage;
+use crate::sync::meta::{MetaObj, SnapshotObj, EntryType};
+
+/// Validation result for snapshot commits
+#[derive(Debug, Clone)]
+pub struct ValidationResult {
+    pub is_valid: bool,
+    pub missing_chunks: Vec<Hash>,
+    pub missing_metas: Vec<(MetaType, Hash)>,
+}
+
+impl ValidationResult {
+    pub fn valid() -> Self {
+        Self {
+            is_valid: true,
+            missing_chunks: Vec::new(),
+            missing_metas: Vec::new(),
+        }
+    }
+
+    pub fn invalid(missing_chunks: Vec<Hash>, missing_metas: Vec<(MetaType, Hash)>) -> Self {
+        Self {
+            is_valid: false,
+            missing_chunks,
+            missing_metas,
+        }
+    }
+
+    pub fn has_missing(&self) -> bool {
+        !self.missing_chunks.is_empty() || !self.missing_metas.is_empty()
+    }
+}
+
+/// Validator for snapshot object graphs
+#[derive(Clone)]
+pub struct SnapshotValidator {
+    storage: Storage,
+}
+
+impl SnapshotValidator {
+    pub fn new(storage: Storage) -> Self {
+        Self { storage }
+    }
+
+    /// Validate a complete snapshot object graph using BFS only
+    pub async fn validate_snapshot(&self, snapshot_hash: &Hash, snapshot_body: &[u8]) -> Result<ValidationResult> {
+        // Use the BFS implementation
+        self.validate_snapshot_bfs(snapshot_hash, snapshot_body).await
+    }
+
+    /// Validate a batch of meta objects (for incremental validation)
+    pub async fn validate_meta_batch(&self, metas: &[(MetaType, Hash)]) -> Result<Vec<(MetaType, Hash)>> {
+        let mut missing = Vec::new();
+        
+        for &(meta_type, hash) in metas {
+            if !self.storage.meta_exists(meta_type, &hash).await {
+                missing.push((meta_type, hash));
+            }
+        }
+        
+        Ok(missing)
+    }
+
+    /// Validate a batch of chunks (for incremental validation)
+    pub async fn validate_chunk_batch(&self, chunks: &[Hash]) -> Result<Vec<Hash>> {
+        let mut missing = Vec::new();
+        
+        for &hash in chunks {
+            if !self.storage.chunk_exists(&hash).await {
+                missing.push(hash);
+            }
+        }
+        
+        Ok(missing)
+    }
+
+    /// Perform a breadth-first validation (useful for large snapshots)
+    pub async fn validate_snapshot_bfs(&self, snapshot_hash: &Hash, snapshot_body: &[u8]) -> Result<ValidationResult> {
+        // Verify snapshot hash
+        let computed_hash = blake3::hash(snapshot_body);
+        if computed_hash.as_bytes() != snapshot_hash {
+            return Err(anyhow::anyhow!("Snapshot hash mismatch"));
+        }
+
+        // Parse snapshot object
+        let snapshot_obj = SnapshotObj::deserialize(bytes::Bytes::from(snapshot_body.to_vec()))
+            .context("Failed to deserialize snapshot object")?;
+
+        let mut missing_chunks = Vec::new();
+        let mut missing_metas = Vec::new();
+        let mut visited_metas = HashSet::new();
+        let mut queue = VecDeque::new();
+
+        // Initialize queue with disk hashes
+        for disk_hash in &snapshot_obj.disk_hashes {
+            queue.push_back((MetaType::Disk, *disk_hash));
+        }
+
+        // BFS traversal
+        while let Some((meta_type, hash)) = queue.pop_front() {
+            let meta_key = (meta_type, hash);
+            
+            if visited_metas.contains(&meta_key) {
+                continue;
+            }
+            visited_metas.insert(meta_key);
+
+            // Check if meta exists
+            if !self.storage.meta_exists(meta_type, &hash).await {
+                println!("Missing metadata: {:?} hash {}", meta_type, hex::encode(&hash));
+                missing_metas.push((meta_type, hash));
+                continue; // Skip loading if missing
+            }
+
+            // Load and process meta object
+            println!("Loading metadata: {:?} hash {}", meta_type, hex::encode(&hash));
+            if let Some(meta_obj) = self.storage.load_meta(meta_type, &hash).await
+                .context("Failed to load meta object")? {
+                
+                match meta_obj {
+                    MetaObj::Disk(disk) => {
+                        for partition_hash in &disk.partition_hashes {
+                            queue.push_back((MetaType::Partition, *partition_hash));
+                        }
+                    }
+                    MetaObj::Partition(partition) => {
+                        queue.push_back((MetaType::Dir, partition.root_dir_hash));
+                    }
+                    MetaObj::Dir(dir) => {
+                        for entry in &dir.entries {
+                            match entry.entry_type {
+                                EntryType::File | EntryType::Symlink => {
+                                    queue.push_back((MetaType::File, entry.target_meta_hash));
+                                }
+                                EntryType::Dir => {
+                                    queue.push_back((MetaType::Dir, entry.target_meta_hash));
+                                }
+                            }
+                        }
+                    }
+                    MetaObj::File(file) => {
+                        // Check chunk dependencies
+                        for chunk_hash in &file.chunk_hashes {
+                            if !self.storage.chunk_exists(chunk_hash).await {
+                                missing_chunks.push(*chunk_hash);
+                            }
+                        }
+                    }
+                    MetaObj::Snapshot(_) => {
+                        // Snapshots shouldn't be nested
+                        return Err(anyhow::anyhow!("Unexpected nested snapshot object"));
+                    }
+                }
+            }
+        }
+
+        if missing_chunks.is_empty() && missing_metas.is_empty() {
+            Ok(ValidationResult::valid())
+        } else {
+            Ok(ValidationResult::invalid(missing_chunks, missing_metas))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+    use crate::sync::meta::*;
+
+    async fn setup_test_storage() -> Storage {
+        let temp_dir = TempDir::new().unwrap();
+        let storage = Storage::new(temp_dir.path());
+        storage.init().await.unwrap();
+        storage
+    }
+
+    #[tokio::test]
+    async fn test_validate_empty_snapshot() {
+        let storage = setup_test_storage().await;
+        let validator = SnapshotValidator::new(storage);
+
+        let snapshot = SnapshotObj::new(1234567890, vec![]);
+        let snapshot_body = snapshot.serialize().unwrap();
+        let snapshot_hash = snapshot.compute_hash().unwrap();
+
+        let result = validator.validate_snapshot(&snapshot_hash, &snapshot_body)
+            .await.unwrap();
+
+        assert!(result.is_valid);
+        assert!(result.missing_chunks.is_empty());
+        assert!(result.missing_metas.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_validate_missing_disk() {
+        let storage = setup_test_storage().await;
+        let validator = SnapshotValidator::new(storage);
+
+        let missing_disk_hash = [1u8; 32];
+        let snapshot = SnapshotObj::new(1234567890, vec![missing_disk_hash]);
+        let snapshot_body = snapshot.serialize().unwrap();
+        let snapshot_hash = snapshot.compute_hash().unwrap();
+
+        let result = validator.validate_snapshot(&snapshot_hash, &snapshot_body)
+            .await.unwrap();
+
+        assert!(!result.is_valid);
+        assert!(result.missing_chunks.is_empty());
+        assert_eq!(result.missing_metas.len(), 1);
+        assert_eq!(result.missing_metas[0], (MetaType::Disk, missing_disk_hash));
+    }
+
+    #[tokio::test]
+    async fn test_validate_chunk_batch() {
+        let storage = setup_test_storage().await;
+        let validator = SnapshotValidator::new(storage);
+
+        let chunk_data = b"test chunk";
+        let chunk_hash = blake3::hash(chunk_data).into();
+        let missing_hash = [1u8; 32];
+
+        // Store one chunk
+        storage.store_chunk(&chunk_hash, chunk_data).await.unwrap();
+
+        let chunks = vec![chunk_hash, missing_hash];
+        let missing = validator.validate_chunk_batch(&chunks).await.unwrap();
+
+        assert_eq!(missing.len(), 1);
+        assert_eq!(missing[0], missing_hash);
+    }
+}

server/src/utils/models.rs

@@ -83,6 +83,8 @@ pub struct Machine {
     pub id: i64,
     pub user_id: i64,
     pub uuid: Uuid,
+    #[serde(rename = "machine_id")]
+    pub machine_id: String,
     pub name: String,
     pub created_at: DateTime<Utc>,
 }

sync_client_test/Cargo.lock

@@ -0,0 +1,76 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "arrayref"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76a2e8124351fda1ef8aaaa3bbd7ebbcb486bbcd4225aca0aa0d84bb2db8fecb"
+
+[[package]]
+name = "arrayvec"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
+
+[[package]]
+name = "blake3"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3888aaa89e4b2a40fca9848e400f6a658a5a3978de7be858e209cafa8be9a4a0"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "cc",
+ "cfg-if",
+ "constant_time_eq",
+]
+
+[[package]]
+name = "cc"
+version = "1.2.36"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5252b3d2648e5eedbc1a6f501e3c795e07025c1e93bbf8bbdd6eef7f447a6d54"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fd1289c04a9ea8cb22300a459a72a385d7c73d3259e2ed7dcb2af674838cfa9"
+
+[[package]]
+name = "constant_time_eq"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c74b8349d32d297c9134b8c88677813a227df8f779daa29bfc29c183fe3dca6"
+
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fd99930f64d146689264c637b5af2f0233a933bef0d8570e2526bf9e083192d"
+
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
+name = "sync_client_test"
+version = "0.1.0"
+dependencies = [
+ "blake3",
+ "hex",
+]

sync_client_test/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "sync_client_test"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+blake3 = "1.5"
+hex = "0.4"

sync_client_test/src/main.rs

@@ -0,0 +1,856 @@
+// Mock sync client for testing the Arkendro sync server
+// This implements the binary protocol specified in PROTOCOL.md
+
+use std::io::{Read, Write, Result, Error, ErrorKind};
+use std::net::TcpStream;
+
+/// Command codes from the protocol
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+enum Command {
+    Hello = 0x01,
+    HelloOk = 0x02,
+    AuthUserPass = 0x10,
+    AuthCode = 0x11,
+    AuthOk = 0x12,
+    AuthFail = 0x13,
+    BatchCheckChunk = 0x20,
+    CheckChunkResp = 0x21,
+    SendChunk = 0x22,
+    ChunkOk = 0x23,
+    ChunkFail = 0x24,
+    BatchCheckMeta = 0x30,
+    CheckMetaResp = 0x31,
+    SendMeta = 0x32,
+    MetaOk = 0x33,
+    MetaFail = 0x34,
+    SendSnapshot = 0x40,
+    SnapshotOk = 0x41,
+    SnapshotFail = 0x42,
+    Close = 0xFF,
+}
+
+impl Command {
+    fn from_u8(value: u8) -> Result<Self> {
+        match value {
+            0x01 => Ok(Command::Hello),
+            0x02 => Ok(Command::HelloOk),
+            0x10 => Ok(Command::AuthUserPass),
+            0x11 => Ok(Command::AuthCode),
+            0x12 => Ok(Command::AuthOk),
+            0x13 => Ok(Command::AuthFail),
+            0x20 => Ok(Command::BatchCheckChunk),
+            0x21 => Ok(Command::CheckChunkResp),
+            0x22 => Ok(Command::SendChunk),
+            0x23 => Ok(Command::ChunkOk),
+            0x24 => Ok(Command::ChunkFail),
+            0x30 => Ok(Command::BatchCheckMeta),
+            0x31 => Ok(Command::CheckMetaResp),
+            0x32 => Ok(Command::SendMeta),
+            0x33 => Ok(Command::MetaOk),
+            0x34 => Ok(Command::MetaFail),
+            0x40 => Ok(Command::SendSnapshot),
+            0x41 => Ok(Command::SnapshotOk),
+            0x42 => Ok(Command::SnapshotFail),
+            0xFF => Ok(Command::Close),
+            _ => Err(Error::new(ErrorKind::InvalidData, "Unknown command")),
+        }
+    }
+}
+
+/// Message header (24 bytes)
+#[derive(Debug)]
+struct MessageHeader {
+    cmd: Command,
+    flags: u8,
+    reserved: [u8; 2],
+    session_id: [u8; 16],
+    payload_len: u32,
+}
+
+impl MessageHeader {
+    fn new(cmd: Command, session_id: [u8; 16], payload_len: u32) -> Self {
+        Self {
+            cmd,
+            flags: 0,
+            reserved: [0; 2],
+            session_id,
+            payload_len,
+        }
+    }
+
+    fn to_bytes(&self) -> [u8; 24] {
+        let mut buf = [0u8; 24];
+        buf[0] = self.cmd as u8;
+        buf[1] = self.flags;
+        buf[2..4].copy_from_slice(&self.reserved);
+        buf[4..20].copy_from_slice(&self.session_id);
+        buf[20..24].copy_from_slice(&self.payload_len.to_le_bytes());
+        buf
+    }
+
+    fn from_bytes(buf: &[u8]) -> Result<Self> {
+        if buf.len() < 24 {
+            return Err(Error::new(ErrorKind::UnexpectedEof, "Header too short"));
+        }
+
+        let cmd = Command::from_u8(buf[0])?;
+        let flags = buf[1];
+        let reserved = [buf[2], buf[3]];
+        let mut session_id = [0u8; 16];
+        session_id.copy_from_slice(&buf[4..20]);
+        let payload_len = u32::from_le_bytes([buf[20], buf[21], buf[22], buf[23]]);
+
+        Ok(Self {
+            cmd,
+            flags,
+            reserved,
+            session_id,
+            payload_len,
+        })
+    }
+}
+
+/// Metadata types
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+enum MetaType {
+    File = 1,
+    Dir = 2,
+    Partition = 3,
+    Disk = 4,
+    Snapshot = 5,
+}
+
+/// Filesystem types
+#[derive(Debug, Clone, Copy)]
+#[repr(u32)]
+enum FsType {
+    Unknown = 0,
+    Ext = 1,
+    Ntfs = 2,
+    Fat32 = 3,
+}
+
+/// Directory entry types
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+enum EntryType {
+    File = 0,
+    Dir = 1,
+    Symlink = 2,
+}
+
+/// Directory entry
+#[derive(Debug, Clone)]
+struct DirEntry {
+    entry_type: EntryType,
+    name: String,
+    target_meta_hash: [u8; 32],
+}
+
+/// File metadata object
+#[derive(Debug, Clone)]
+struct FileObj {
+    version: u8,
+    fs_type_code: FsType,
+    size: u64,
+    mode: u32,
+    uid: u32,
+    gid: u32,
+    mtime_unixsec: u64,
+    chunk_hashes: Vec<[u8; 32]>,
+}
+
+impl FileObj {
+    fn new(size: u64, chunk_hashes: Vec<[u8; 32]>) -> Self {
+        Self {
+            version: 1,
+            fs_type_code: FsType::Ext,
+            size,
+            mode: 0o644,
+            uid: 1000,
+            gid: 1000,
+            mtime_unixsec: std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_secs(),
+            chunk_hashes,
+        }
+    }
+
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        buf.push(self.version);
+        buf.extend_from_slice(&(self.fs_type_code as u32).to_le_bytes());
+        buf.extend_from_slice(&self.size.to_le_bytes());
+        buf.extend_from_slice(&self.mode.to_le_bytes());
+        buf.extend_from_slice(&self.uid.to_le_bytes());
+        buf.extend_from_slice(&self.gid.to_le_bytes());
+        buf.extend_from_slice(&self.mtime_unixsec.to_le_bytes());
+        buf.extend_from_slice(&(self.chunk_hashes.len() as u32).to_le_bytes());
+        for hash in &self.chunk_hashes {
+            buf.extend_from_slice(hash);
+        }
+        buf
+    }
+}
+
+/// Directory metadata object
+#[derive(Debug, Clone)]
+struct DirObj {
+    version: u8,
+    entries: Vec<DirEntry>,
+}
+
+impl DirObj {
+    fn new(entries: Vec<DirEntry>) -> Self {
+        Self {
+            version: 1,
+            entries,
+        }
+    }
+
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        buf.push(self.version);
+        buf.extend_from_slice(&(self.entries.len() as u32).to_le_bytes());
+        
+        for entry in &self.entries {
+            buf.push(entry.entry_type as u8);
+            let name_bytes = entry.name.as_bytes();
+            buf.extend_from_slice(&(name_bytes.len() as u16).to_le_bytes());
+            buf.extend_from_slice(name_bytes);
+            buf.extend_from_slice(&entry.target_meta_hash);
+        }
+        buf
+    }
+}
+
+/// Partition metadata object
+#[derive(Debug, Clone)]
+struct PartitionObj {
+    version: u8,
+    fs_type: FsType,
+    root_dir_hash: [u8; 32],
+    start_lba: u64,
+    end_lba: u64,
+    type_guid: [u8; 16],
+}
+
+impl PartitionObj {
+    fn new(label: String, root_dir_hash: [u8; 32]) -> Self {
+        // Generate a deterministic GUID from the label for testing
+        let mut type_guid = [0u8; 16];
+        let label_bytes = label.as_bytes();
+        for (i, &byte) in label_bytes.iter().take(16).enumerate() {
+            type_guid[i] = byte;
+        }
+        
+        Self {
+            version: 1,
+            fs_type: FsType::Ext,
+            root_dir_hash,
+            start_lba: 2048,  // Common starting LBA
+            end_lba: 2097152, // ~1GB partition
+            type_guid,
+        }
+    }
+
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        buf.push(self.version);
+        buf.extend_from_slice(&(self.fs_type as u32).to_le_bytes());
+        buf.extend_from_slice(&self.root_dir_hash);
+        buf.extend_from_slice(&self.start_lba.to_le_bytes());
+        buf.extend_from_slice(&self.end_lba.to_le_bytes());
+        buf.extend_from_slice(&self.type_guid);
+        buf
+    }
+}
+
+/// Disk metadata object
+#[derive(Debug, Clone)]
+struct DiskObj {
+    version: u8,
+    partition_hashes: Vec<[u8; 32]>,
+    disk_size_bytes: u64,
+    serial: String,
+}
+
+impl DiskObj {
+    fn new(serial: String, partition_hashes: Vec<[u8; 32]>) -> Self {
+        Self {
+            version: 1,
+            partition_hashes,
+            disk_size_bytes: 1024 * 1024 * 1024, // 1GB default
+            serial,
+        }
+    }
+
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        buf.push(self.version);
+        buf.extend_from_slice(&(self.partition_hashes.len() as u32).to_le_bytes());
+        for hash in &self.partition_hashes {
+            buf.extend_from_slice(hash);
+        }
+        buf.extend_from_slice(&self.disk_size_bytes.to_le_bytes());
+        let serial_bytes = self.serial.as_bytes();
+        buf.extend_from_slice(&(serial_bytes.len() as u16).to_le_bytes());
+        buf.extend_from_slice(serial_bytes);
+        buf
+    }
+}
+
+/// Snapshot metadata object
+#[derive(Debug, Clone)]
+struct SnapshotObj {
+    version: u8,
+    created_at_unixsec: u64,
+    disk_hashes: Vec<[u8; 32]>,
+}
+
+impl SnapshotObj {
+    fn new(disk_hashes: Vec<[u8; 32]>) -> Self {
+        Self {
+            version: 1,
+            created_at_unixsec: std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_secs(),
+            disk_hashes,
+        }
+    }
+
+    fn serialize(&self) -> Vec<u8> {
+        let mut buf = Vec::new();
+        buf.push(self.version);
+        buf.extend_from_slice(&self.created_at_unixsec.to_le_bytes());
+        buf.extend_from_slice(&(self.disk_hashes.len() as u32).to_le_bytes());
+        for hash in &self.disk_hashes {
+            buf.extend_from_slice(hash);
+        }
+        buf
+    }
+}
+
+/// Simple sync client for testing
+struct SyncClient {
+    stream: TcpStream,
+    session_id: [u8; 16],
+}
+
+impl SyncClient {
+    fn connect(addr: &str) -> Result<Self> {
+        let stream = TcpStream::connect(addr)?;
+        Ok(Self {
+            stream,
+            session_id: [0; 16],
+        })
+    }
+
+    fn send_message(&mut self, cmd: Command, payload: &[u8]) -> Result<()> {
+        let header = MessageHeader::new(cmd, self.session_id, payload.len() as u32);
+        
+        self.stream.write_all(&header.to_bytes())?;
+        if !payload.is_empty() {
+            self.stream.write_all(payload)?;
+        }
+        self.stream.flush()?;
+        Ok(())
+    }
+
+    fn receive_message(&mut self) -> Result<(Command, Vec<u8>)> {
+        // Read header
+        let mut header_buf = [0u8; 24];
+        self.stream.read_exact(&mut header_buf)?;
+        let header = MessageHeader::from_bytes(&header_buf)?;
+
+        // Read payload
+        let mut payload = vec![0u8; header.payload_len as usize];
+        if header.payload_len > 0 {
+            self.stream.read_exact(&mut payload)?;
+        }
+
+        Ok((header.cmd, payload))
+    }
+
+    fn hello(&mut self) -> Result<()> {
+        println!("Sending HELLO...");
+        // Hello message needs client_type (1 byte) and auth_type (1 byte)
+        let payload = vec![0x01, 0x01]; // client_type=1, auth_type=1 
+        self.send_message(Command::Hello, &payload)?;
+        
+        let (cmd, _payload) = self.receive_message()?;
+        match cmd {
+            Command::HelloOk => {
+                println!("✓ Received HELLO_OK");
+                Ok(())
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected HELLO_OK")),
+        }
+    }
+
+    fn authenticate(&mut self, username: &str, password: &str, machine_id: i64) -> Result<()> {
+        println!("Authenticating as {} with machine ID {}...", username, machine_id);
+        
+        // Build auth payload: username_len (u16_le) + username + password_len (u16_le) + password + machine_id (i64_le)
+        let mut payload = Vec::new();
+        payload.extend_from_slice(&(username.len() as u16).to_le_bytes());
+        payload.extend_from_slice(username.as_bytes());
+        payload.extend_from_slice(&(password.len() as u16).to_le_bytes());
+        payload.extend_from_slice(password.as_bytes());
+        payload.extend_from_slice(&machine_id.to_le_bytes());
+
+        self.send_message(Command::AuthUserPass, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::AuthOk => {
+                // Extract session ID from payload
+                if payload.len() >= 16 {
+                    self.session_id.copy_from_slice(&payload[0..16]);
+                    println!("✓ Authentication successful! Session ID: {:?}", self.session_id);
+                    Ok(())
+                } else {
+                    Err(Error::new(ErrorKind::InvalidData, "Invalid session ID"))
+                }
+            }
+            Command::AuthFail => Err(Error::new(ErrorKind::PermissionDenied, "Authentication failed")),
+            _ => Err(Error::new(ErrorKind::InvalidData, "Unexpected response")),
+        }
+    }
+
+    fn check_chunks(&mut self, hashes: &[[u8; 32]]) -> Result<Vec<[u8; 32]>> {
+        println!("Checking {} chunks...", hashes.len());
+        
+        let mut payload = Vec::new();
+        payload.extend_from_slice(&(hashes.len() as u32).to_le_bytes());
+        for hash in hashes {
+            payload.extend_from_slice(hash);
+        }
+
+        self.send_message(Command::BatchCheckChunk, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::CheckChunkResp => {
+                if payload.len() < 4 {
+                    return Err(Error::new(ErrorKind::InvalidData, "Invalid response"));
+                }
+
+                let count = u32::from_le_bytes([payload[0], payload[1], payload[2], payload[3]]) as usize;
+                let mut missing = Vec::new();
+                
+                for i in 0..count {
+                    let start = 4 + i * 32;
+                    if payload.len() < start + 32 {
+                        return Err(Error::new(ErrorKind::InvalidData, "Invalid hash in response"));
+                    }
+                    let mut hash = [0u8; 32];
+                    hash.copy_from_slice(&payload[start..start + 32]);
+                    missing.push(hash);
+                }
+
+                println!("✓ {} chunks missing out of {}", missing.len(), hashes.len());
+                Ok(missing)
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected CheckChunkResp")),
+        }
+    }
+
+    fn send_chunk(&mut self, hash: &[u8; 32], data: &[u8]) -> Result<()> {
+        println!("Sending chunk {} bytes...", data.len());
+        println!("Chunk hash: {}", hex::encode(hash));
+        
+        // Verify hash matches data
+        let computed_hash = blake3_hash(data);
+        if computed_hash != *hash {
+            return Err(Error::new(ErrorKind::InvalidData, "Hash mismatch"));
+        }
+
+        let mut payload = Vec::new();
+        payload.extend_from_slice(hash);
+        payload.extend_from_slice(&(data.len() as u32).to_le_bytes());
+        payload.extend_from_slice(data);
+
+        self.send_message(Command::SendChunk, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::ChunkOk => {
+                println!("✓ Chunk uploaded successfully");
+                Ok(())
+            }
+            Command::ChunkFail => {
+                let reason = if !payload.is_empty() {
+                    String::from_utf8_lossy(&payload).to_string()
+                } else {
+                    "Unknown error".to_string()
+                };
+                Err(Error::new(ErrorKind::Other, format!("Server rejected chunk: {}", reason)))
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected ChunkOk or ChunkFail")),
+        }
+    }
+
+    fn check_metadata(&mut self, items: &[(MetaType, [u8; 32])]) -> Result<Vec<(MetaType, [u8; 32])>> {
+        println!("Checking {} metadata items...", items.len());
+        
+        let mut payload = Vec::new();
+        payload.extend_from_slice(&(items.len() as u32).to_le_bytes());
+        for (meta_type, hash) in items {
+            payload.push(*meta_type as u8);
+            payload.extend_from_slice(hash);
+        }
+
+        self.send_message(Command::BatchCheckMeta, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::CheckMetaResp => {
+                if payload.len() < 4 {
+                    return Err(Error::new(ErrorKind::InvalidData, "Invalid response"));
+                }
+
+                let count = u32::from_le_bytes([payload[0], payload[1], payload[2], payload[3]]) as usize;
+                let mut missing = Vec::new();
+                
+                for i in 0..count {
+                    let start = 4 + i * 33; // 1 byte type + 32 bytes hash
+                    if payload.len() < start + 33 {
+                        return Err(Error::new(ErrorKind::InvalidData, "Invalid metadata in response"));
+                    }
+                    let meta_type = match payload[start] {
+                        1 => MetaType::File,
+                        2 => MetaType::Dir,
+                        3 => MetaType::Partition,
+                        4 => MetaType::Disk,
+                        5 => MetaType::Snapshot,
+                        _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid metadata type")),
+                    };
+                    let mut hash = [0u8; 32];
+                    hash.copy_from_slice(&payload[start + 1..start + 33]);
+                    missing.push((meta_type, hash));
+                }
+
+                println!("✓ {} metadata items missing out of {}", missing.len(), items.len());
+                Ok(missing)
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected CheckMetaResp")),
+        }
+    }
+
+    fn send_metadata(&mut self, meta_type: MetaType, meta_hash: &[u8; 32], body: &[u8]) -> Result<()> {
+        println!("Sending {:?} metadata {} bytes...", meta_type, body.len());
+        println!("Metadata hash: {}", hex::encode(meta_hash));
+        
+        // Verify hash matches body
+        let computed_hash = blake3_hash(body);
+        if computed_hash != *meta_hash {
+            return Err(Error::new(ErrorKind::InvalidData, "Metadata hash mismatch"));
+        }
+
+        let mut payload = Vec::new();
+        payload.push(meta_type as u8);
+        payload.extend_from_slice(meta_hash);
+        payload.extend_from_slice(&(body.len() as u32).to_le_bytes());
+        payload.extend_from_slice(body);
+
+        self.send_message(Command::SendMeta, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::MetaOk => {
+                println!("✓ Metadata uploaded successfully");
+                Ok(())
+            }
+            Command::MetaFail => {
+                let reason = if !payload.is_empty() {
+                    String::from_utf8_lossy(&payload).to_string()
+                } else {
+                    "Unknown error".to_string()
+                };
+                Err(Error::new(ErrorKind::Other, format!("Server rejected metadata: {}", reason)))
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected MetaOk or MetaFail")),
+        }
+    }
+
+    fn send_snapshot(&mut self, snapshot_hash: &[u8; 32], snapshot_data: &[u8]) -> Result<()> {
+        println!("Sending snapshot {} bytes...", snapshot_data.len());
+        println!("Snapshot hash: {}", hex::encode(snapshot_hash));
+        
+        // Verify hash matches data
+        let computed_hash = blake3_hash(snapshot_data);
+        if computed_hash != *snapshot_hash {
+            return Err(Error::new(ErrorKind::InvalidData, "Snapshot hash mismatch"));
+        }
+
+        let mut payload = Vec::new();
+        payload.extend_from_slice(snapshot_hash);
+        payload.extend_from_slice(&(snapshot_data.len() as u32).to_le_bytes());
+        payload.extend_from_slice(snapshot_data);
+
+        self.send_message(Command::SendSnapshot, &payload)?;
+        
+        let (cmd, payload) = self.receive_message()?;
+        match cmd {
+            Command::SnapshotOk => {
+                println!("✓ Snapshot uploaded successfully");
+                Ok(())
+            }
+            Command::SnapshotFail => {
+                // Parse SnapshotFail payload: missing_chunks_count + chunks + missing_metas_count + metas
+                if payload.len() < 8 {
+                    return Err(Error::new(ErrorKind::Other, "Server rejected snapshot: Invalid response format"));
+                }
+                
+                let missing_chunks_count = u32::from_le_bytes([payload[0], payload[1], payload[2], payload[3]]) as usize;
+                let missing_metas_count = u32::from_le_bytes([payload[4], payload[5], payload[6], payload[7]]) as usize;
+                
+                let mut error_msg = format!("Server rejected snapshot: {} missing chunks, {} missing metadata items", 
+                    missing_chunks_count, missing_metas_count);
+                
+                // Optionally parse the actual missing items for more detailed error
+                if missing_chunks_count > 0 || missing_metas_count > 0 {
+                    error_msg.push_str(" (run with chunk/metadata verification to see details)");
+                }
+                
+                Err(Error::new(ErrorKind::Other, error_msg))
+            }
+            _ => Err(Error::new(ErrorKind::InvalidData, "Expected SnapshotOk or SnapshotFail")),
+        }
+    }
+
+    fn close(&mut self) -> Result<()> {
+        self.send_message(Command::Close, &[])?;
+        Ok(())
+    }
+}
+
+/// Hash function using blake3
+fn blake3_hash(data: &[u8]) -> [u8; 32] {
+    blake3::hash(data).into()
+}
+
+/// Generate some mock data for testing
+fn generate_mock_data() -> Vec<(Vec<u8>, [u8; 32])> {
+    let mut data_chunks = Vec::new();
+    
+    // Some test data chunks
+    let chunks = [
+        b"Hello, Arkendro sync server! This is test chunk data.".to_vec(),
+        b"Another test chunk with different content for variety.".to_vec(),
+        b"Binary data test: \x00\x01\x02\x03\xFF\xFE\xFD\xFC".to_vec(),
+    ];
+    
+    for chunk in chunks {
+        let hash = blake3_hash(&chunk);
+        data_chunks.push((chunk, hash));
+    }
+    
+    data_chunks
+}
+
+fn main() -> Result<()> {
+    println!("🚀 Arkendro Sync Client Extended Test");
+    println!("====================================\n");
+
+    // Connect to server
+    let mut client = SyncClient::connect("127.0.0.1:8380")?;
+    println!("Connected to sync server\n");
+
+    // Test protocol flow
+    client.hello()?;
+    
+    // Try to authenticate with hardcoded machine ID (you'll need to create a machine first via the web interface)
+    let machine_id = 1; // Hardcoded machine ID for testing
+    match client.authenticate("admin", "password123", machine_id) {
+        Ok(()) => println!("Authentication successful!\n"),
+        Err(e) => {
+            println!("Authentication failed: {}", e);
+            println!("Make sure you have:");
+            println!("1. Created a user 'admin' with password 'password123' via the web interface");
+            println!("2. Created a machine with ID {} that belongs to user 'admin'", machine_id);
+            client.close()?;
+            return Ok(());
+        }
+    }
+
+    println!("📁 Creating test filesystem hierarchy...\n");
+
+    // Step 1: Create test file data chunks
+    let file1_data = b"Hello, this is the content of file1.txt in our test filesystem!";
+    let file2_data = b"This is file2.log with some different content for testing purposes.";
+    let file3_data = b"Binary data file: \x00\x01\x02\x03\xFF\xFE\xFD\xFC and some text after.";
+    
+    let file1_hash = blake3_hash(file1_data);
+    let file2_hash = blake3_hash(file2_data);
+    let file3_hash = blake3_hash(file3_data);
+
+    // Upload chunks if needed
+    println!("🔗 Uploading file chunks...");
+    let chunk_hashes = vec![file1_hash, file2_hash, file3_hash];
+    let missing_chunks = client.check_chunks(&chunk_hashes)?;
+    
+    if !missing_chunks.is_empty() {
+        for &missing_hash in &missing_chunks {
+            if missing_hash == file1_hash {
+                client.send_chunk(&file1_hash, file1_data)?;
+            } else if missing_hash == file2_hash {
+                client.send_chunk(&file2_hash, file2_data)?;
+            } else if missing_hash == file3_hash {
+                client.send_chunk(&file3_hash, file3_data)?;
+            }
+        }
+    } else {
+        println!("✓ All chunks already exist on server");
+    }
+
+    // Step 2: Create file metadata objects
+    println!("\n📄 Creating file metadata objects...");
+    let file1_obj = FileObj::new(file1_data.len() as u64, vec![file1_hash]);
+    let file2_obj = FileObj::new(file2_data.len() as u64, vec![file2_hash]);
+    let file3_obj = FileObj::new(file3_data.len() as u64, vec![file3_hash]);
+
+    let file1_meta_data = file1_obj.serialize();
+    let file2_meta_data = file2_obj.serialize();
+    let file3_meta_data = file3_obj.serialize();
+
+    let file1_meta_hash = blake3_hash(&file1_meta_data);
+    let file2_meta_hash = blake3_hash(&file2_meta_data);
+    let file3_meta_hash = blake3_hash(&file3_meta_data);
+
+    // Upload file metadata
+    client.send_metadata(MetaType::File, &file1_meta_hash, &file1_meta_data)?;
+    client.send_metadata(MetaType::File, &file2_meta_hash, &file2_meta_data)?;
+    client.send_metadata(MetaType::File, &file3_meta_hash, &file3_meta_data)?;
+
+    // Step 3: Create directory structures
+    println!("\n📁 Creating directory structures...");
+    
+    // Create /logs subdirectory with file2
+    let logs_dir_entries = vec![
+        DirEntry {
+            entry_type: EntryType::File,
+            name: "app.log".to_string(),
+            target_meta_hash: file2_meta_hash,
+        },
+    ];
+    let logs_dir_obj = DirObj::new(logs_dir_entries);
+    let logs_dir_data = logs_dir_obj.serialize();
+    let logs_dir_hash = blake3_hash(&logs_dir_data);
+    client.send_metadata(MetaType::Dir, &logs_dir_hash, &logs_dir_data)?;
+
+    // Create /data subdirectory with file3
+    let data_dir_entries = vec![
+        DirEntry {
+            entry_type: EntryType::File,
+            name: "binary.dat".to_string(),
+            target_meta_hash: file3_meta_hash,
+        },
+    ];
+    let data_dir_obj = DirObj::new(data_dir_entries);
+    let data_dir_data = data_dir_obj.serialize();
+    let data_dir_hash = blake3_hash(&data_dir_data);
+    client.send_metadata(MetaType::Dir, &data_dir_hash, &data_dir_data)?;
+
+    // Create root directory with file1 and subdirectories
+    let root_dir_entries = vec![
+        DirEntry {
+            entry_type: EntryType::File,
+            name: "readme.txt".to_string(),
+            target_meta_hash: file1_meta_hash,
+        },
+        DirEntry {
+            entry_type: EntryType::Dir,
+            name: "logs".to_string(),
+            target_meta_hash: logs_dir_hash,
+        },
+        DirEntry {
+            entry_type: EntryType::Dir,
+            name: "data".to_string(),
+            target_meta_hash: data_dir_hash,
+        },
+    ];
+    let root_dir_obj = DirObj::new(root_dir_entries);
+    let root_dir_data = root_dir_obj.serialize();
+    let root_dir_hash = blake3_hash(&root_dir_data);
+    client.send_metadata(MetaType::Dir, &root_dir_hash, &root_dir_data)?;
+
+    // Step 4: Create partition
+    println!("\n💽 Creating partition metadata...");
+    let partition_obj = PartitionObj::new("test-partition".to_string(), root_dir_hash);
+    let partition_data = partition_obj.serialize();
+    let partition_hash = blake3_hash(&partition_data);
+    client.send_metadata(MetaType::Partition, &partition_hash, &partition_data)?;
+
+    // Step 5: Create disk
+    println!("\n🖥️  Creating disk metadata...");
+    let disk_obj = DiskObj::new("test-disk-001".to_string(), vec![partition_hash]);
+    let disk_data = disk_obj.serialize();
+    let disk_hash = blake3_hash(&disk_data);
+    client.send_metadata(MetaType::Disk, &disk_hash, &disk_data)?;
+
+    // Step 6: Create snapshot
+    println!("\n📸 Creating snapshot...");
+    let snapshot_obj = SnapshotObj::new(vec![disk_hash]);
+    let snapshot_data = snapshot_obj.serialize();
+    let snapshot_hash = blake3_hash(&snapshot_data);
+    
+    // Upload snapshot using SendSnapshot command (not SendMeta)
+    client.send_snapshot(&snapshot_hash, &snapshot_data)?;
+
+    // Step 7: Verify everything is stored
+    println!("\n🔍 Verifying stored objects...");
+    
+    // Check all metadata objects
+    let all_metadata = vec![
+        (MetaType::File, file1_meta_hash),
+        (MetaType::File, file2_meta_hash),
+        (MetaType::File, file3_meta_hash),
+        (MetaType::Dir, logs_dir_hash),
+        (MetaType::Dir, data_dir_hash),
+        (MetaType::Dir, root_dir_hash),
+        (MetaType::Partition, partition_hash),
+        (MetaType::Disk, disk_hash),
+        (MetaType::Snapshot, snapshot_hash),
+    ];
+    
+    let missing_metadata = client.check_metadata(&all_metadata)?;
+    if missing_metadata.is_empty() {
+        println!("✓ All metadata objects verified as stored");
+    } else {
+        println!("⚠ Warning: {} metadata objects still missing", missing_metadata.len());
+        for (meta_type, hash) in missing_metadata {
+            println!("  - Missing {:?}: {}", meta_type, hex::encode(hash));
+        }
+    }
+
+    // Check all chunks
+    let all_chunks = vec![file1_hash, file2_hash, file3_hash];
+    let missing_chunks_final = client.check_chunks(&all_chunks)?;
+    if missing_chunks_final.is_empty() {
+        println!("✓ All data chunks verified as stored");
+    } else {
+        println!("⚠ Warning: {} chunks still missing", missing_chunks_final.len());
+    }
+
+    println!("\n🎉 Complete filesystem hierarchy created!");
+    println!("📊 Summary:");
+    println!("  • 3 files (readme.txt, logs/app.log, data/binary.dat)");
+    println!("  • 3 directories (/, /logs, /data)");
+    println!("  • 1 partition (test-partition)");
+    println!("  • 1 disk (test-disk-001)");
+    println!("  • 1 snapshot");
+    println!("  • Snapshot hash: {}", hex::encode(snapshot_hash));
+
+    println!("\n✅ All tests completed successfully!");
+    
+    // Close connection
+    client.close()?;
+    
+    Ok(())
+}

webui/src/App.jsx

@@ -6,6 +6,7 @@ import Root from "@/common/layouts/Root.jsx";
 import UserManagement from "@/pages/UserManagement";
 import SystemSettings from "@/pages/SystemSettings";
 import Machines from "@/pages/Machines";
+import MachineDetails from "@/pages/MachineDetails";
 import "@fontsource/plus-jakarta-sans/300.css";
 import "@fontsource/plus-jakarta-sans/400.css";
 import "@fontsource/plus-jakarta-sans/600.css";
@@ -24,6 +25,7 @@ const App = () => {
                 {path: "/", element: <Navigate to="/dashboard"/>},
                 {path: "/dashboard", element: <Placeholder title="Dashboard"/>},
                 {path: "/machines", element: <Machines/>},
+                {path: "/machines/:id", element: <MachineDetails/>},
                 {path: "/servers", element: <Placeholder title="Servers"/>},
                 {path: "/settings", element: <Placeholder title="Settings"/>},
                 {path: "/admin/users", element: <UserManagement/>},

webui/src/pages/MachineDetails/MachineDetails.jsx

@@ -0,0 +1,416 @@
+import React, { useState, useEffect } from 'react';
+import { useParams, useNavigate } from 'react-router-dom';
+import { getRequest } from '@/common/utils/RequestUtil.js';
+import { useToast } from '@/common/contexts/ToastContext.jsx';
+import Card, { CardHeader, CardBody } from '@/common/components/Card';
+import Grid from '@/common/components/Grid';
+import LoadingSpinner from '@/common/components/LoadingSpinner';
+import EmptyState from '@/common/components/EmptyState';
+import PageHeader from '@/common/components/PageHeader';
+import DetailItem, { DetailList } from '@/common/components/DetailItem';
+import Badge from '@/common/components/Badge';
+import Button from '@/common/components/Button';
+import {
+    ArrowLeft,
+    Camera,
+    HardDrive,
+    Folder,
+    Calendar,
+    Hash,
+    Database,
+    Devices,
+    Eye,
+    ArrowCircleLeft
+} from '@phosphor-icons/react';
+import './styles.sass';
+
+export const MachineDetails = () => {
+    const { id } = useParams();
+    const navigate = useNavigate();
+    const toast = useToast();
+    const [machine, setMachine] = useState(null);
+    const [snapshots, setSnapshots] = useState([]);
+    const [loading, setLoading] = useState(true);
+    const [selectedSnapshot, setSelectedSnapshot] = useState(null);
+    const [snapshotDetails, setSnapshotDetails] = useState(null);
+    const [loadingDetails, setLoadingDetails] = useState(false);
+
+    useEffect(() => {
+        if (id) {
+            fetchMachineData();
+        }
+    }, [id]);
+
+    const fetchMachineData = async () => {
+        try {
+            setLoading(true);
+            
+            // Fetch machine info and snapshots in parallel
+            const [machineResponse, snapshotsResponse] = await Promise.all([
+                getRequest(`machines/${id}`),
+                getRequest(`machines/${id}/snapshots`)
+            ]);
+            
+            setMachine(machineResponse);
+            setSnapshots(snapshotsResponse);
+        } catch (error) {
+            console.error('Failed to fetch machine data:', error);
+            toast.error('Failed to load machine details');
+        } finally {
+            setLoading(false);
+        }
+    };
+
+    const fetchSnapshotDetails = async (snapshotId) => {
+        try {
+            setLoadingDetails(true);
+            const details = await getRequest(`machines/${id}/snapshots/${snapshotId}`);
+            setSnapshotDetails(details);
+            setSelectedSnapshot(snapshotId);
+        } catch (error) {
+            console.error('Failed to fetch snapshot details:', error);
+            toast.error('Failed to load snapshot details');
+        } finally {
+            setLoadingDetails(false);
+        }
+    };
+
+    const backToSnapshots = () => {
+        setSelectedSnapshot(null);
+        setSnapshotDetails(null);
+    };
+
+    const formatBytes = (bytes) => {
+        if (!bytes) return '0 B';
+        const k = 1024;
+        const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
+        const i = Math.floor(Math.log(bytes) / Math.log(k));
+        return `${parseFloat((bytes / Math.pow(k, i)).toFixed(2))} ${sizes[i]}`;
+    };
+
+    const formatDate = (dateString) => {
+        if (!dateString || dateString === 'Unknown') return 'Unknown';
+        try {
+            // Handle both "2025-09-09 20:19:48" and "2025-09-09 20:19:48 UTC" formats
+            const cleanDate = dateString.replace(' UTC', '');
+            const date = new Date(cleanDate);
+            if (isNaN(date.getTime())) {
+                return dateString; // Return original if parsing fails
+            }
+            return date.toLocaleString('en-US', {
+                year: 'numeric',
+                month: 'short',
+                day: 'numeric',
+                hour: '2-digit',
+                minute: '2-digit',
+                second: '2-digit'
+            });
+        } catch {
+            return dateString;
+        }
+    };
+
+    const formatLBA = (lba) => {
+        if (!lba && lba !== 0) return '0';
+        return lba.toLocaleString();
+    };
+
+    const getFsTypeColor = (fsType) => {
+        switch (fsType?.toLowerCase()) {
+            case 'ext':
+            case 'ext4':
+            case 'ext3':
+            case 'ext2':
+                return 'success';
+            case 'ntfs':
+                return 'info';
+            case 'fat32':
+            case 'fat':
+                return 'warning';
+            case 'xfs':
+                return 'info';
+            case 'btrfs':
+                return 'success';
+            default:
+                return 'secondary';
+        }
+    };
+
+    const truncateHash = (hash, length = 16) => {
+        if (!hash) return 'Unknown';
+        return hash.length > length ? `${hash.substring(0, length)}...` : hash;
+    };
+
+    if (loading) {
+        return (
+            <div className="machine-details">
+                <PageHeader
+                    title="Loading..."
+                    subtitle="Fetching machine details"
+                    actions={
+                        <Button variant="secondary" onClick={() => navigate('/machines')}>
+                            <ArrowLeft size={16} />
+                            Back to Machines
+                        </Button>
+                    }
+                />
+                <LoadingSpinner />
+            </div>
+        );
+    }
+
+    if (!machine) {
+        return (
+            <div className="machine-details">
+                <PageHeader
+                    title="Machine Not Found"
+                    subtitle="The requested machine could not be found"
+                    actions={
+                        <Button variant="secondary" onClick={() => navigate('/machines')}>
+                            <ArrowLeft size={16} />
+                            Back to Machines
+                        </Button>
+                    }
+                />
+                <EmptyState
+                    icon={<Devices size={48} weight="duotone" />}
+                    title="Machine Not Found"
+                    subtitle="This machine may have been deleted or you don't have access to it."
+                />
+            </div>
+        );
+    }
+
+    return (
+        <div className="machine-details">
+            <PageHeader
+                title={machine.name}
+                subtitle={
+                    selectedSnapshot 
+                        ? `Snapshot Details` 
+                        : `Machine ID: ${machine.machine_id}`
+                }
+                actions={
+                    selectedSnapshot ? (
+                        <Button variant="secondary" onClick={backToSnapshots}>
+                            <ArrowCircleLeft size={16} />
+                            Back to Snapshots
+                        </Button>
+                    ) : (
+                        <Button variant="secondary" onClick={() => navigate('/machines')}>
+                            <ArrowLeft size={16} />
+                            Back to Machines
+                        </Button>
+                    )
+                }
+            />
+
+            <Grid columns={1} gap="large">
+                {/* Machine Information - Only show when not viewing snapshot details */}
+                {!selectedSnapshot && (
+                    <Card>
+                        <CardHeader>
+                            <h3><Devices size={20} /> Machine Information</h3>
+                        </CardHeader>
+                        <CardBody>
+                            <DetailList>
+                                <DetailItem label="Name" value={machine.name} />
+                                <DetailItem label="Machine ID" value={machine.machine_id} />
+                                <DetailItem label="Created" value={formatDate(machine.created_at)} />
+                                <DetailItem label="Status" value={
+                                    <Badge variant="success">Active</Badge>
+                                } />
+                            </DetailList>
+                        </CardBody>
+                    </Card>
+                )}
+
+                {/* Snapshots List or Details */}
+                {!selectedSnapshot ? (
+                    /* Snapshots List */
+                    <Card>
+                        <CardHeader>
+                            <h3><Camera size={20} /> Snapshots ({snapshots.length})</h3>
+                        </CardHeader>
+                        <CardBody>
+                            {snapshots.length === 0 ? (
+                                <EmptyState
+                                    icon={<Camera size={48} weight="duotone" />}
+                                    title="No Snapshots"
+                                    subtitle="This machine hasn't created any snapshots yet."
+                                />
+                            ) : (
+                                <Grid columns={1} gap="medium">
+                                    {snapshots.map((snapshot) => (
+                                        <Card key={snapshot.id} className="snapshot-summary-card">
+                                            <CardBody>
+                                                <div className="snapshot-summary">
+                                                    <div className="snapshot-info">
+                                                        <div className="snapshot-title">
+                                                            <Camera size={18} />
+                                                            <h4>Snapshot</h4>
+                                                        </div>
+                                                        <DetailList>
+                                                            <DetailItem 
+                                                                label="Created" 
+                                                                value={
+                                                                    <div className="snapshot-date">
+                                                                        <Calendar size={14} />
+                                                                        {formatDate(snapshot.created_at)}
+                                                                    </div>
+                                                                } 
+                                                            />
+                                                            <DetailItem 
+                                                                label="Snapshot ID" 
+                                                                value={
+                                                                    <div className="snapshot-hash">
+                                                                        <Hash size={14} />
+                                                                        <code>{truncateHash(snapshot.id, 24)}</code>
+                                                                    </div>
+                                                                } 
+                                                            />
+                                                            <DetailItem 
+                                                                label="Hash" 
+                                                                value={
+                                                                    <div className="snapshot-hash">
+                                                                        <Hash size={14} />
+                                                                        <code>{truncateHash(snapshot.snapshot_hash, 24)}</code>
+                                                                    </div>
+                                                                } 
+                                                            />
+                                                        </DetailList>
+                                                    </div>
+                                                    <div className="snapshot-actions">
+                                                        <Button 
+                                                            variant="primary" 
+                                                            size="small"
+                                                            onClick={() => fetchSnapshotDetails(snapshot.id)}
+                                                        >
+                                                            <Eye size={16} />
+                                                            View Details
+                                                        </Button>
+                                                    </div>
+                                                </div>
+                                            </CardBody>
+                                        </Card>
+                                    ))}
+                                </Grid>
+                            )}
+                        </CardBody>
+                    </Card>
+                ) : (
+                    /* Snapshot Details */
+                    <Card>
+                        <CardHeader>
+                            <h3><Camera size={20} /> Snapshot {selectedSnapshot} Details</h3>
+                        </CardHeader>
+                        <CardBody>
+                            {loadingDetails ? (
+                                <LoadingSpinner />
+                            ) : snapshotDetails ? (
+                                <div className="snapshot-details">
+                                    {/* Snapshot Metadata */}
+                                    <Card className="snapshot-metadata">
+                                        <CardHeader>
+                                            <h4><Database size={18} /> Metadata</h4>
+                                        </CardHeader>
+                                        <CardBody>
+                                            <DetailList>
+                                                <DetailItem 
+                                                    label="Created" 
+                                                    value={
+                                                        <div className="snapshot-date">
+                                                            <Calendar size={14} />
+                                                            {formatDate(snapshotDetails.created_at)}
+                                                        </div>
+                                                    } 
+                                                />
+                                                <DetailItem 
+                                                    label="Hash" 
+                                                    value={
+                                                        <div className="snapshot-hash">
+                                                            <Hash size={14} />
+                                                            <code>{snapshotDetails.snapshot_hash}</code>
+                                                        </div>
+                                                    } 
+                                                />
+                                                <DetailItem 
+                                                    label="Disks" 
+                                                    value={`${snapshotDetails.disks.length} disk${snapshotDetails.disks.length !== 1 ? 's' : ''}`} 
+                                                />
+                                            </DetailList>
+                                        </CardBody>
+                                    </Card>
+
+                                    {/* Disks */}
+                                    <div className="disks-section">
+                                        <h4><HardDrive size={18} /> Disks ({snapshotDetails.disks.length})</h4>
+                                        <Grid columns={1} gap="medium">
+                                            {snapshotDetails.disks.map((disk, diskIndex) => (
+                                                <Card key={diskIndex} className="disk-card">
+                                                    <CardHeader>
+                                                        <h5><HardDrive size={16} /> Disk {diskIndex + 1}</h5>
+                                                    </CardHeader>
+                                                    <CardBody>
+                                                        <DetailList>
+                                                            <DetailItem label="Serial" value={disk.serial || 'Unknown'} />
+                                                            <DetailItem label="Size" value={formatBytes(disk.size_bytes)} />
+                                                            <DetailItem 
+                                                                label="Partitions" 
+                                                                value={`${disk.partitions.length} partition${disk.partitions.length !== 1 ? 's' : ''}`} 
+                                                            />
+                                                        </DetailList>
+
+                                                        {/* Partitions */}
+                                                        {disk.partitions.length > 0 && (
+                                                            <div className="partitions-section">
+                                                                <h6><Folder size={14} /> Partitions</h6>
+                                                                <Grid columns="auto-fit" gap="1rem" minWidth="280px">
+                                                                    {disk.partitions.map((partition, partIndex) => (
+                                                                        <Card key={partIndex} className="partition-card">
+                                                                            <CardHeader>
+                                                                                <div className="partition-header">
+                                                                                    <span>Partition {partIndex + 1}</span>
+                                                                                    <Badge variant={getFsTypeColor(partition.fs_type)}>
+                                                                                        {partition.fs_type.toUpperCase()}
+                                                                                    </Badge>
+                                                                                </div>
+                                                                            </CardHeader>
+                                                                            <CardBody>
+                                                                                <DetailList>
+                                                                                    <DetailItem label="Size" value={formatBytes(partition.size_bytes)} />
+                                                                                    <DetailItem label="Start LBA" value={formatLBA(partition.start_lba)} />
+                                                                                    <DetailItem label="End LBA" value={formatLBA(partition.end_lba)} />
+                                                                                    <DetailItem 
+                                                                                        label="Sectors" 
+                                                                                        value={formatLBA(partition.end_lba - partition.start_lba)} 
+                                                                                    />
+                                                                                </DetailList>
+                                                                            </CardBody>
+                                                                        </Card>
+                                                                    ))}
+                                                                </Grid>
+                                                            </div>
+                                                        )}
+                                                    </CardBody>
+                                                </Card>
+                                            ))}
+                                        </Grid>
+                                    </div>
+                                </div>
+                            ) : (
+                                <EmptyState
+                                    icon={<Camera size={48} weight="duotone" />}
+                                    title="No Details Available"
+                                    subtitle="Unable to load snapshot details."
+                                />
+                            )}
+                        </CardBody>
+                    </Card>
+                )}
+            </Grid>
+        </div>
+    );
+};
+
+export default MachineDetails;

webui/src/pages/MachineDetails/index.js

@@ -0,0 +1,2 @@
+export { default } from './MachineDetails.jsx';
+export { MachineDetails } from './MachineDetails.jsx';

webui/src/pages/MachineDetails/styles.sass

@@ -0,0 +1,232 @@
+// Machine Details Page Styles
+.machine-details
+  // Snapshot Summary Cards (list view)
+  .snapshot-summary-card
+    transition: all 0.2s ease
+    cursor: pointer
+    
+    &:hover
+      border-color: var(--border-strong)
+      box-shadow: 0 4px 12px rgba(31, 36, 41, 0.1)
+      transform: translateY(-1px)
+
+    .snapshot-summary
+      display: flex
+      justify-content: space-between
+      align-items: flex-start
+      gap: 1.5rem
+      
+      .snapshot-info
+        flex: 1
+        
+        .snapshot-title
+          display: flex
+          align-items: center
+          gap: 0.75rem
+          margin-bottom: 1rem
+          
+          h4
+            font-size: 1.125rem
+            font-weight: 600
+            color: var(--text)
+            margin: 0
+
+        .snapshot-date
+          display: flex
+          align-items: center
+          gap: 0.5rem
+          font-size: 0.875rem
+          color: var(--text-dim)
+          
+        .snapshot-hash
+          display: flex
+          align-items: center
+          gap: 0.5rem
+          font-size: 0.875rem
+          
+          code
+            background: var(--bg-elev)
+            padding: 0.25rem 0.5rem
+            border-radius: var(--radius-sm)
+            font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', monospace
+            color: var(--text-dim)
+            font-size: 0.8rem
+      
+      .snapshot-actions
+        display: flex
+        flex-direction: column
+        gap: 0.5rem
+
+  // Snapshot Detail View
+  .snapshot-details
+    .snapshot-metadata
+      margin-bottom: 2rem
+      background: linear-gradient(135deg, var(--bg-alt) 0%, var(--bg-elev) 100%)
+      border: 1px solid var(--border)
+      
+    .disks-section
+      h4
+        font-size: 1.25rem
+        font-weight: 600
+        color: var(--text)
+        margin-bottom: 1.5rem
+        display: flex
+        align-items: center
+        gap: 0.75rem
+        padding-bottom: 0.5rem
+        border-bottom: 2px solid var(--border)
+
+  .disk-card
+    border: 1px solid var(--border)
+    background: linear-gradient(135deg, var(--bg-alt) 0%, var(--bg-elev) 100%)
+    transition: all 0.2s ease
+    position: relative
+    overflow: hidden
+    
+    &::before
+      content: ''
+      position: absolute
+      top: 0
+      left: 0
+      right: 0
+      height: 3px
+      background: linear-gradient(90deg, var(--accent) 0%, var(--success) 100%)
+      opacity: 0
+      transition: opacity 0.2s ease
+    
+    &:hover
+      border-color: var(--border-strong)
+      box-shadow: 0 6px 20px rgba(31, 36, 41, 0.15)
+      transform: translateY(-2px)
+      
+      &::before
+        opacity: 1
+
+    .partitions-section
+      margin-top: 2rem
+      
+      h6
+        font-size: 1rem
+        font-weight: 600
+        color: var(--text)
+        margin-bottom: 1rem
+        display: flex
+        align-items: center
+        gap: 0.5rem
+        padding: 0.5rem 0
+        border-bottom: 1px solid var(--border)
+
+  .partition-card
+    border: 1px solid var(--border)
+    background: var(--bg-elev)
+    transition: all 0.2s ease
+    position: relative
+    
+    &:hover
+      border-color: var(--border-strong)
+      box-shadow: 0 3px 10px rgba(31, 36, 41, 0.1)
+      transform: translateY(-1px)
+      
+    .partition-header
+      display: flex
+      justify-content: space-between
+      align-items: center
+      
+      span
+        font-size: 0.875rem
+        font-weight: 600
+        color: var(--text)
+
+  // Enhanced visual feedback
+  .snapshot-date, .snapshot-hash
+    transition: color 0.2s ease
+    
+    &:hover
+      color: var(--text)
+
+  // Better spacing for detail items
+  .detail-list
+    .detail-item
+      padding: 0.75rem 0
+      border-bottom: 1px solid var(--border)
+      
+      &:last-child
+        border-bottom: none
+      
+      .detail-label
+        font-weight: 500
+        color: var(--text-dim)
+        font-size: 0.875rem
+        text-transform: uppercase
+        letter-spacing: 0.05em
+        
+      .detail-value
+        font-weight: 500
+        color: var(--text)
+        
+        code
+          background: var(--bg-elev)
+          padding: 0.25rem 0.5rem
+          border-radius: var(--radius-sm)
+          font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', monospace
+          font-size: 0.8rem
+          border: 1px solid var(--border)
+
+  // Loading and error states
+  .loading-section
+    text-align: center
+    padding: 3rem
+    
+    .spinner
+      border: 3px solid var(--border)
+      border-top: 3px solid var(--accent)
+      border-radius: 50%
+      width: 40px
+      height: 40px
+      animation: spin 1s linear infinite
+      margin: 0 auto 1rem
+      
+    @keyframes spin
+      0%
+        transform: rotate(0deg)
+      100%
+        transform: rotate(360deg)
+
+  // Responsive design
+  @media (max-width: 768px)
+    .snapshot-summary
+      flex-direction: column
+      gap: 1rem
+      
+      .snapshot-actions
+        flex-direction: row
+        align-self: stretch
+
+    .disk-card .partitions-section h6
+      font-size: 0.875rem
+      
+    .disks-section h4
+      font-size: 1.125rem
+
+  // Visual hierarchy improvements
+  .card
+    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1)
+    
+    &:hover
+      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15)
+      
+  .badge
+    font-weight: 600
+    letter-spacing: 0.025em
+    
+    &.variant-success
+      background: linear-gradient(135deg, var(--success) 0%, #22c55e 100%)
+      
+    &.variant-info
+      background: linear-gradient(135deg, var(--info) 0%, #3b82f6 100%)
+      
+    &.variant-warning
+      background: linear-gradient(135deg, var(--warning) 0%, #f59e0b 100%)
+      
+    &.variant-secondary
+      background: linear-gradient(135deg, var(--text-dim) 0%, #6b7280 100%)

webui/src/pages/Machines/Machines.jsx

@@ -1,4 +1,5 @@
 import React, {useState, useEffect, useContext} from 'react';
+import {useNavigate} from 'react-router-dom';
 import {UserContext} from '@/common/contexts/UserContext.jsx';
 import {useToast} from '@/common/contexts/ToastContext.jsx';
 import {getRequest, postRequest, deleteRequest} from '@/common/utils/RequestUtil.js';
@@ -28,6 +29,7 @@ import './styles.sass';
 export const Machines = () => {
     const {user: currentUser} = useContext(UserContext);
     const toast = useToast();
+    const navigate = useNavigate();
     const [machines, setMachines] = useState([]);
     const [loading, setLoading] = useState(true);
     const [showCreateModal, setShowCreateModal] = useState(false);
@@ -179,6 +181,14 @@ export const Machines = () => {
         }
     };
 
+    const handleMachineClick = (machineId) => {
+        navigate(`/machines/${machineId}`);
+    };
+
+    const handleActionClick = (e) => {
+        e.stopPropagation(); // Prevent navigation when clicking action buttons
+    };
+
     const handleInputChange = (e) => {
         const {name, value} = e.target;
         setFormData(prev => ({
@@ -220,7 +230,13 @@ export const Machines = () => {
 
             <Grid minWidth="400px">
                 {machines.map(machine => (
-                    <Card key={machine.id} hover className="machine-card">
+                    <Card 
+                        key={machine.id} 
+                        hover 
+                        className="machine-card"
+                        onClick={() => handleMachineClick(machine.id)}
+                        style={{ cursor: 'pointer' }}
+                    >
                         <CardHeader>
                             <div className="machine-card-header">
                                 <div className="machine-icon">
@@ -233,7 +249,7 @@ export const Machines = () => {
                                         <span className="uuid-text">{formatUuid(machine.uuid)}</span>
                                     </div>
                                 </div>
-                                <div className="machine-actions">
+                                <div className="machine-actions" onClick={handleActionClick}>
                                     <Button
                                         variant="subtle"
                                         size="sm"