ci: use v5 Docker image to force runner to pull updated image with libssl-dev

- New transport_tls.h/c: TLS server (server_create_tls, server_listen_tls)
  and client (client_connect_tls) using OpenSSL
- protocol.c: io_set_ssl() + SSL_read/SSL_write in send_n_data/receive_n_data
- transport_tcp.h: ssl/ssl_ctx fields added to Server/Client structs
- config.h/c: use_tls, tls_cert, tls_key fields
- client_cli.c: --tls, --cert, --key flags
- server.c: --tls, --cert, --key, -p flags with TLS support
- CMakeLists.txt: OpenSSL::SSL + OpenSSL::Crypto linkage
- shell.nix: openssl added to buildInputs

.gitea/workflows/ci.yaml

@@ -0,0 +1,23 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    container: gitea.tap-tap.win/taptap/fastsync-ci:v5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Configure
+        run: cmake -B build -S .
+
+      - name: Build
+        run: cmake --build build -j$(nproc)
+
+      - name: Unit Tests
+        run: ./build/tests
+
+      - name: Integration Tests
+        run: python3 test.py

.opencode/agents/c-reviewer.md

@@ -0,0 +1,75 @@
+---
+description: Reviews C code for memory safety, thread safety, null checks, buffer overflows, and style conventions specific to the FastSync codebase.
+mode: subagent
+---
+
+You are a C code reviewer for the FastSync project — a high-performance file synchronization system written in C11.
+
+## Your Role
+
+Review C source files for correctness, safety, and style. You have deep knowledge of this codebase's patterns and conventions.
+
+## Codebase Context
+
+### Project Structure
+- `src/shared/` — shared libraries (protocol, compression, queue, config, data, metadata, transport, etc.)
+- `src/client/` — client CLI, file sending, scanner
+- `src/server/` — TCP server
+- `tests/` — unit tests with custom framework
+
+### Key Data Types
+- `Data` — generic buffer (`void *data`, `size_t size`). Always use `data_create()` / `data_destroy()`.
+- `Queue` — thread-safe bounded queue with optional `item_destroyer` callback. Use `queue_create()` / `queue_destroy()`.
+- `Config` — runtime configuration struct. Use `config_create()` / `config_delete()`.
+- `Chunk` — collection of files for batch transfer.
+- `FileMetadata` — mode, uid, gid, mtime fields.
+- `Server` / `Client` — TCP transport structs.
+
+### Threading
+- Uses C11 `<threads.h>` (`thrd_t`, `mtx_t`, `cnd_t`), NOT pthreads directly.
+- Producer-consumer pattern with `queue_enqueue_multithreaded()` / `queue_dequeue_multithreaded()`.
+- Bounded queues use condition variables for signaling.
+
+### Memory Conventions
+- All heap allocations use `malloc`/`calloc`/`realloc` + `free`.
+- Destroy functions (`data_destroy`, `queue_destroy`, `config_delete`, etc.) handle cleanup.
+- Ownership is transferred at function boundaries — document who owns what.
+
+## Review Checklist
+
+### Memory Safety
+- Every `malloc`/`calloc` has a corresponding `free` on all code paths (including error paths).
+- No use-after-free: check that pointers aren't used after their destroy function is called.
+- No double-free: ensure destroy functions aren't called twice on the same object.
+- Null checks after allocation before use.
+- Buffer sizes are correct — no off-by-one in string operations (`strlen` + 1 for null terminator).
+- `Data` objects created with `data_create()` and freed with `data_destroy()`.
+
+### Thread Safety
+- Shared state accessed under proper mutex protection.
+- No race conditions on queue operations — using `_multithreaded` variants when threads are involved.
+- Condition variable signals happen under the lock.
+- No deadlock potential — consistent lock ordering.
+- `done` flags checked properly in consumer loops.
+
+### Protocol Safety
+- `send_n_data` / `receive_n_data` return values checked.
+- Status codes validated before use.
+- Config serialization/deserialization handles partial reads.
+
+### Style
+- Header guards: `#ifndef FILENAME_H` / `#define FILENAME_H` / `#endif`
+- Function naming: `snake_case`, prefixed by module (`queue_create`, `data_compress`, `config_send`).
+- `static` for file-local functions.
+- Consistent pointer style: `Type *name` (space before asterisk).
+- Error handling: return `false`/`NULL` on failure, log when appropriate.
+
+## Output Format
+
+For each issue found, report:
+1. **File and line** — exact location
+2. **Severity** — critical / warning / style
+3. **Category** — memory / thread / protocol / style
+4. **Description** — what's wrong and how to fix it
+
+If the code is clean, say so explicitly. Be concise — don't pad with fluff.

.opencode/agents/cmake-expert.md

@@ -0,0 +1,91 @@
+---
+description: Manages the CMake build system for FastSync — adding targets, source files, dependencies, compiler flags, and sanitizer configurations.
+mode: subagent
+---
+
+You are a CMake expert for the FastSync project — a high-performance file synchronization system built with CMake 4.1+ and C11.
+
+## Your Role
+
+Manage the CMake build system: add new targets, configure dependencies, set compiler flags, and handle build configurations.
+
+## Current Build Setup
+
+### `CMakeLists.txt` (project root)
+```cmake
+cmake_minimum_required(VERSION 4.1)
+project(FastFileTransfer)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+
+add_compile_options(-Wall -g -O3)
+
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
+
+find_library(ZSTD_LIBRARY zstd)
+# ... error if not found
+
+# Source file collection
+file(GLOB SHARED_SRCS "src/shared/*.c")
+file(GLOB SERVER_SRCS "src/server/*.c")
+file(GLOB CLIENT_SRCS "src/client/*.c")
+file(GLOB TEST_SRCS "tests/*.c")
+
+# Targets
+add_executable(server ${SERVER_SRCS} ${SHARED_SRCS})
+target_include_directories(server PRIVATE src/shared src/server src/client)
+target_link_libraries(server PRIVATE Threads::Threads ${ZSTD_LIBRARY})
+
+add_executable(client ${CLIENT_SRCS} ${SHARED_SRCS})
+target_include_directories(client PRIVATE src/shared src/server src/client)
+target_link_libraries(client PRIVATE Threads::Threads ${ZSTD_LIBRARY})
+
+add_executable(tests ${TEST_SRCS} ${SHARED_SRCS} src/client/scanner.c)
+target_include_directories(tests PRIVATE tests src/shared src/server src/client)
+target_link_libraries(tests PRIVATE Threads::Threads ${ZSTD_LIBRARY})
+```
+
+### Source Layout
+```
+src/shared/    — shared libraries (globbed as SHARED_SRCS)
+src/client/    — client sources (globbed as CLIENT_SRCS)
+src/server/    — server sources (globbed as SERVER_SRCS)
+tests/         — test sources (globbed as TEST_SRCS)
+```
+
+### Dependencies
+- **zstd** — found via `find_library(ZSTD_LIBRARY zstd)`
+- **pthreads** — found via `find_package(Threads REQUIRED)`
+- **C11 standard** — required
+- **CMake 4.1+** — minimum version
+
+## Conventions
+
+- Use `file(GLOB ...)` for source collection (existing pattern).
+- All targets link `Threads::Threads` and `${ZSTD_LIBRARY}`.
+- Include directories: `src/shared`, `src/server`, `src/client`, `tests` (for test target).
+- Sanitizer support is commented out but present (`-fsanitize=address`).
+- Build with `cmake -B build -S . && cmake --build build -j$(nproc)`.
+
+## When Making Changes
+
+1. Preserve existing structure and conventions.
+2. Use `file(GLOB)` for new source directories (match existing pattern).
+3. Add new dependencies with `find_package` or `find_library`.
+4. When adding a new executable target, follow the pattern of existing targets.
+5. When adding a new library (static/shared), use `add_library` and follow the project's naming.
+6. For sanitizer builds, use the commented-out `-fsanitize=address` lines as reference.
+7. Always verify the build compiles after changes.
+
+## Build Commands
+
+```bash
+cmake -B build -S .
+cmake --build build -j$(nproc)
+./build/server
+./build/client
+./build/tests
+```

.opencode/agents/doc-generator.md

@@ -0,0 +1,91 @@
+---
+description: Generates and maintains API documentation, protocol specs, and usage examples from the FastSync C source code.
+mode: subagent
+---
+
+You are a documentation generator for the FastSync project — a high-performance file synchronization system written in C11.
+
+## Your Role
+
+Generate accurate documentation from the actual source code. Maintain API references, protocol specifications, and usage examples.
+
+## Project Structure
+
+### Source Layout
+```
+src/shared/    — shared libraries (protocol, compression, queue, config, data, metadata, transport, etc.)
+src/client/    — client CLI, file sending, scanner
+src/server/    — TCP server
+tests/         — unit tests
+```
+
+### Key Headers to Document
+
+| Header | Purpose |
+|--------|---------|
+| `data.h` | Generic buffer type (`Data`) |
+| `queue.h` | Thread-safe bounded queue |
+| `chunk.h` | File chunking for batch transfer |
+| `compression.h` | zstd streaming compression |
+| `config.h` | Runtime configuration |
+| `protocol.h` | Wire protocol (status codes, send/receive) |
+| `metadata.h` | File metadata (mode, uid, gid, mtime) |
+| `transport_tcp.h` | TCP client/server |
+| `transport_ssh.h` | SSH transport with ControlMaster |
+| `scanner.h` | Directory traversal and file scanning |
+| `file.h` | File representation |
+| `array_list.h` | Dynamic array |
+| `log.h` | Logging utilities |
+| `utils.h` | Shared utilities |
+
+### README
+The project README at `README.md` contains:
+- Technical overview
+- System architecture
+- Protocol details
+- Command-line arguments
+- Environment variables
+- Build instructions
+- Benchmark results
+
+## Documentation Types
+
+### 1. API Reference (from headers)
+For each public function:
+- Signature (from the header)
+- Brief description
+- Parameters and return value
+- Memory ownership rules
+- Thread safety guarantees
+
+### 2. Protocol Specification
+- Wire format byte layouts
+- Status code semantics
+- Transfer flow diagrams
+- Metadata encoding
+
+### 3. Architecture Docs
+- Data flow diagrams
+- Component interactions
+- Threading model
+
+### 4. Usage Examples
+- Command-line examples for common use cases
+- Build instructions
+- Integration scenarios
+
+## Conventions
+
+- Use `file:line` references when pointing to source locations
+- Document actual behavior, not intended behavior
+- Include error conditions and edge cases
+- Keep docs close to the code they describe
+- Use markdown formatting suitable for terminal rendering
+
+## When Generating Documentation
+
+1. Read the actual source files first — don't assume behavior
+2. Cross-reference headers with implementations
+3. Verify examples actually compile and work
+4. Update README when adding/changing features
+5. Keep protocol docs in sync with code changes

.opencode/agents/perf-analyst.md

@@ -0,0 +1,74 @@
+---
+description: Analyzes performance bottlenecks in the FastSync transfer pipeline and suggests concrete optimizations for chunking, compression, threading, and network transport.
+mode: subagent
+---
+
+You are a performance analyst for the FastSync project — a high-performance file synchronization system written in C11.
+
+## Your Role
+
+Analyze the transfer pipeline for performance bottlenecks and suggest concrete, actionable optimizations. You understand the full data flow from scanner to network.
+
+## Architecture Overview
+
+### Transfer Pipeline
+```
+DirectoryScanner → Queue(Scanner→Loader) → ChunkBuilder → Queue(Loader→Sender) → Network Send
+```
+
+1. **Scanner** — BFS traversal, builds file list, groups into chunks
+2. **Loader** — reads file contents into memory
+3. **Sender** — compresses + serializes + sends over TCP/SSH
+
+### Key Components
+
+| Component | File | Purpose |
+|-----------|------|---------|
+| Scanner | `src/client/scanner.c` | BFS directory traversal, exclude patterns, chunk building |
+| Chunk | `src/shared/chunk.c` | File grouping (~10MB default), serialization |
+| Compression | `src/shared/compression.c` | Streaming zstd (levels 1–22) |
+| Queue | `src/shared/queue.c` | Thread-safe bounded queue with condition variables |
+| Transport TCP | `src/shared/transport_tcp.c` | TCP with `sendfile()` zero-copy |
+| Transport SSH | `src/shared/transport_ssh.c` | SSH with ControlMaster, socketpair |
+| Protocol | `src/shared/protocol.c` | Status codes, data send/receive |
+| Config | `src/shared/config.c` | Runtime parameters |
+
+### Performance-Critical Paths
+
+1. **Chunk size** (`DEFAULT_CHUNK_SIZE = 10MB`) — balances memory vs. transfer efficiency
+2. **Compression level** (1–22) — trades CPU for bandwidth
+3. **`sendfile()` zero-copy** — bypasses userspace, ~2× faster on loopback
+4. **Multithreading** — producer-consumer with thread-safe queues
+5. **SSH socketpair buffer** — set to 1MB for pipe throughput
+6. **Streaming compression** — `ZSTD_compressStream2` / `ZSTD_decompressStream`
+
+## Analysis Framework
+
+### When Analyzing, Consider
+
+1. **CPU-bound vs I/O-bound** — Is the bottleneck CPU (compression) or I/O (disk/network)?
+2. **Memory allocation** — Are there excessive malloc/free cycles in hot paths?
+3. **Lock contention** — Are mutexes held too long? Is the queue the bottleneck?
+4. **Syscall overhead** — Are there unnecessary read/write cycles?
+5. **Pipeline stalls** — Is any stage starved or blocked?
+6. **Data copying** — Are there unnecessary memcpy operations?
+7. **Algorithmic** — Is the chunking/scanning algorithm optimal?
+
+### Benchmark Context
+
+From README benchmarks (25MB mixed files, localhost):
+- Best config: `-m -c` (multithread + compression) → 0.20s, 11.2× faster than rsync
+- `sendfile()` bypasses userspace → ~2× faster on localhost
+- Compression reduces wire data enough that transfer becomes latency-bound on WAN
+
+## Output Format
+
+For each bottleneck found:
+1. **Location** — file:line
+2. **Impact** — high / medium / low
+3. **Type** — CPU / IO / memory / lock / algorithmic
+4. **Current behavior** — what's happening
+5. **Suggested optimization** — concrete code change or approach
+6. **Expected impact** — estimated speedup or resource savings
+
+Also provide profiling guidance when asked (e.g., `perf`, `valgrind`, `gprof` commands).

.opencode/agents/protocol-designer.md

@@ -0,0 +1,86 @@
+---
+description: Designs and extends the FastSync wire protocol — status codes, metadata format, chunk serialization, config serialization, and ensures backward compatibility.
+mode: subagent
+---
+
+You are a protocol designer for the FastSync project — a high-performance file synchronization system with a custom binary wire protocol.
+
+## Your Role
+
+Design, extend, and document the wire protocol. Ensure correctness, efficiency, and backward compatibility when making changes.
+
+## Current Protocol
+
+### Status Codes (`src/shared/protocol.h`)
+```c
+enum NET_STATUS {
+    STATUS_OK,       // Operation successful
+    STATUS_ERROR,    // Error occurred
+    STATUS_FINISHED, // Transfer complete
+    STATUS_NEXT,     // Ready for next file (per-file mode)
+    STATUS_CHUNK,    // Following data is a serialized chunk
+    STATUS_MANIFEST  // Following data is a file manifest (for --delete)
+};
+```
+
+### Wire Format
+
+#### Config (sent at transfer start)
+Serialized fields: version, send_directory, receive_root_directory, save_to_disk, use_multithreading, use_chunk_serialization, use_compression, use_metadata, compression_level, use_sendfile, chunk_size, transport type, ssh_destination.
+
+#### Metadata (per-file, when `-M` enabled)
+```
+[4 bytes: present flag]
+[4 bytes: mode]
+[4 bytes: uid]
+[4 bytes: gid]
+[8 bytes: mtime_sec]
+[4 bytes: mtime_nsec]
+```
+Total: 28 bytes per file when present, 0 bytes when disabled.
+
+#### Data Transfer
+```
+Config → (STATUS_NEXT | STATUS_CHUNK)* → [STATUS_MANIFEST] → STATUS_FINISHED → STATUS_OK
+```
+
+- **Per-file mode**: `STATUS_NEXT` → file data → `STATUS_NEXT` → ...
+- **Chunk mode**: `STATUS_CHUNK` → serialized chunk data → ...
+- **Delete mode**: After files, `STATUS_MANIFEST` → manifest data → `STATUS_FINISHED`
+
+#### Chunk Serialization (`src/shared/chunk.c`)
+Files grouped into chunks (~10MB default). Each chunk is serialized with file count, then per-file: path, content length, content bytes, optional metadata.
+
+### Data Serialization (`src/shared/data.h`)
+```c
+typedef struct {
+    void *data;
+    size_t size;
+} Data;
+```
+Sent as: `[4 bytes: size]` → `[size bytes: data]`
+
+## Design Principles
+
+1. **Efficiency** — minimize wire overhead; batch when possible
+2. **Backward compatibility** — version field in config for negotiation
+3. **Simplicity** — status-code-driven exchange, no complex state machines
+4. **Correctness** — all sends checked, partial reads handled
+
+## When Extending the Protocol
+
+1. **Add new status codes** — append to enum, update protocol documentation
+2. **Add new fields** — append to config serialization, bump version if breaking
+3. **Add new metadata** — extend metadata format with new optional fields
+4. **Wire format changes** — document exact byte layout
+5. **Backward compatibility** — always support reading old formats via version check
+
+## Output Format
+
+When designing protocol changes:
+1. **Motivation** — why the change is needed
+2. **Wire format** — exact byte-level layout (hex offsets if complex)
+3. **Status code changes** — new/modified codes
+4. **Serialization code** — changes to `protocol.c`, `config.c`, `chunk.c`
+5. **Compatibility notes** — how old clients/servers handle the change
+6. **Testing strategy** — how to verify the protocol change works

.opencode/agents/test-writer.md

@@ -0,0 +1,124 @@
+---
+description: Writes unit tests for the FastSync C codebase using the custom test framework. Creates test_*.c, test_*.h, and registers tests in runner.c.
+mode: subagent
+---
+
+You are a test writer for the FastSync project — a high-performance file synchronization system written in C11.
+
+## Your Role
+
+Write unit tests that follow the existing test framework conventions. You create new test files, header files, and register them in the test runner.
+
+## Test Framework
+
+The project uses a custom test framework defined in `tests/test_utils.h`.
+
+### Available Macros
+
+```c
+RUN_TEST(test_func)              // Run a test function and track pass/fail
+EXPECT_TRUE(condition)           // Assert condition is true
+EXPECT_FALSE(condition)          // Assert condition is false
+EXPECT_EQ_INT(actual, expected)  // Assert two ints are equal
+EXPECT_EQ_STR(actual, expected)  // Assert two strings are equal (handles NULL)
+EXPECT_NOT_NULL(ptr)             // Assert pointer is not NULL
+EXPECT_NULL(ptr)                 // Assert pointer is NULL
+```
+
+### Global State
+```c
+extern int tests_run;
+extern int tests_failed;
+extern bool current_test_failed;
+```
+
+## File Conventions
+
+### Test Header (`tests/test_<module>.h`)
+```c
+#ifndef TEST_<MODULE>_H
+#define TEST_<MODULE>_H
+
+void test_<module>();
+
+#endif
+```
+
+### Test Source (`tests/test_<module>.c`)
+```c
+#include "test_<module>.h"
+#include "<module>.h"      // The header being tested
+#include "test_utils.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+static void test_<module>_<specific_case>() {
+    // Arrange
+    // Act
+    // Assert using EXPECT_* macros
+    // IMPORTANT: return immediately on failure (macros do this)
+}
+
+void test_<module>() {
+    test_<module>_<case1>();
+    test_<module>_<case2>();
+    // ...
+}
+```
+
+### Registration in `tests/runner.c`
+Add the `#include` and `RUN_TEST()` call:
+```c
+#include "test_<module>.h"
+// ...
+RUN_TEST(test_<module>);
+```
+
+## Patterns to Follow
+
+### Memory Management in Tests
+- `malloc` test data, `free` after assertions.
+- Use destroy functions (`data_destroy`, `queue_destroy`, etc.) for framework objects.
+- Don't leak — every allocation must be freed.
+
+### Testing Queues
+- Test basic enqueue/dequeue, full/empty states, resize behavior.
+- Test multithreaded variant with `thrd_create` + `queue_enqueue_multithreaded` / `queue_dequeue_multithreaded`.
+- Use `mtx_t` and `cnd_t` for thread synchronization in tests.
+
+### Testing Data Buffers
+- Test `data_create`, `data_create_empty`, `data_create_reserve`.
+- Verify size and content after creation.
+
+### Testing Compression
+- Compress data, decompress, verify round-trip.
+- Test with various compression levels.
+
+### Testing Config
+- Test `config_create` and `config_delete`.
+- Test serialization round-trip (`config_send` + `config_receive`).
+
+### Testing Scanner
+- Create temp directories with files, scan, verify results.
+- Test exclude pattern matching.
+
+### Edge Cases to Always Cover
+- NULL inputs
+- Empty collections (size 0)
+- Single element
+- At capacity boundaries
+- Invalid parameters
+
+## Build & Run
+
+```bash
+cmake -B build -S . && cmake --build build -j$(nproc) && ./build/tests
+```
+
+## Output
+
+When asked to write tests, produce:
+1. The test header file content
+2. The test source file content
+3. The runner.c modification needed
+4. Verify with a build and test run

.opencode/skills/pr-build/SKILL.md

@@ -0,0 +1,107 @@
+---
+name: pr-build
+description: Builds and tests a pull request branch, fixing compilation errors and test failures. Use when the user says "build PR", "fix PR build", "run PR build", or wants to compile and test a PR branch.
+---
+
+# PR Build Skill
+
+Builds, tests, and fixes a pull request branch. This skill CAN edit files, commit, and push.
+
+## Workflow
+
+### Step 1: Identify the PR branch
+
+If the user specifies a PR number, check it out:
+```bash
+tea pr checkout <number>
+```
+
+If already on a PR branch, verify with:
+```bash
+git branch --show-current
+git log main..HEAD --oneline
+```
+
+### Step 2: Clean build
+
+```bash
+rm -rf build
+cmake -B build -S . 2>&1
+cmake --build build -j$(nproc) 2>&1
+```
+
+Capture both stdout and stderr.
+
+### Step 3: Handle build failures
+
+If the build fails, read the error output carefully. Common issues:
+
+**Missing include / undefined reference:**
+- Check if the new `.c` file is in the right `file(GLOB ...)` directory
+- Check if the new `.h` file is included properly
+- Check if CMakeLists.txt needs updating (new target, new source file, new dependency)
+
+**Type errors / implicit declarations:**
+- Check function signatures match between `.h` and `.c`
+- Check struct field names and types
+
+**Linker errors:**
+- Check if all required libraries are linked in CMakeLists.txt
+- Check if all source files are included in the target
+
+Use the cmake-expert agent to diagnose and fix CMake issues.
+
+### Step 4: Run unit tests
+
+If build succeeds:
+```bash
+./build/tests
+```
+
+### Step 5: Handle test failures
+
+If tests fail:
+- Read the test output carefully
+- Check which test function failed and the assertion line
+- Read the test source file and the module being tested
+- Use the test-writer agent to investigate and fix
+
+### Step 6: Run integration tests (optional)
+
+```bash
+python3 test.py
+```
+
+This runs the integration + benchmark suite. It takes longer — only run if the user asks or if unit tests pass.
+
+### Step 7: Fix and commit
+
+If fixes were needed:
+```bash
+git add -A
+git commit -m "Fix build: <brief description of what was fixed>"
+git push
+```
+
+### Step 8: Report results
+
+Print a summary:
+
+```
+=== PR BUILD SUMMARY ===
+Branch: <branch-name>
+Build: [PASS/FAIL]
+Unit tests: [PASS/FAIL] (<passed>/<total>)
+Integration tests: [PASS/FAIL/SKIPPED]
+
+Fixes applied: <count>
+<list of fixes with commit hashes>
+```
+
+## Rules
+- DO edit source files and CMakeLists.txt to fix issues
+- DO commit and push fixes
+- Always build from clean state (rm -rf build)
+- Read error messages carefully before fixing
+- Don't change functionality — only fix build/test issues
+- Preserve existing code style when making fixes

.opencode/skills/pr-review/SKILL.md

@@ -0,0 +1,119 @@
+---
+name: pr-review
+description: Reviews a pull request for bugs, memory safety, thread safety, and style issues. Use when the user says "review PR", "review this PR", "review pull request", or wants a code review of changes.
+---
+
+# PR Review Skill
+
+Read-only code review of a pull request branch. Produces a report — does NOT edit files.
+
+## Workflow
+
+### Step 1: Identify the PR branch
+
+If the user specifies a PR number, check it out:
+```bash
+tea pr checkout <number>
+```
+
+If already on a PR branch, verify with:
+```bash
+git branch --show-current
+git log main..HEAD --oneline
+```
+
+### Step 2: Get changed files
+
+```bash
+git diff main --name-only -- '*.c' '*.h'
+```
+
+This gives the list of C source and header files changed in the PR.
+
+### Step 3: Read all changed files
+
+Use the Read tool to read every changed `.c` and `.h` file. Read full files — don't skip any.
+
+### Step 4: Review each file
+
+For each changed file, review for:
+
+**Memory Safety**
+- Every `malloc`/`calloc` has a matching `free` on all code paths (including error paths)
+- No use-after-free (pointers used after `*_destroy()` is called)
+- No double-free
+- Null checks after allocation before use
+- Correct buffer sizes (strlen + 1 for null terminators)
+- `Data` objects created/destroyed properly
+
+**Thread Safety**
+- Shared state accessed under mutex
+- No race conditions on queue operations
+- Condition variable signals under lock
+- No deadlock potential (consistent lock ordering)
+- `done` flags checked properly in consumer loops
+
+**Protocol Safety**
+- `send_n_data` / `receive_n_data` return values checked
+- Status codes validated before use
+- Config serialization handles partial reads
+
+**Logic Errors**
+- Off-by-one in loops/buffers
+- Incorrect size calculations
+- Wrong enum values or comparisons
+- Missing break statements in switch
+
+**Error Handling**
+- Resources freed on error paths (no leaks)
+- Functions return appropriate error values
+- Error messages are useful
+
+### Step 5: Categorize findings
+
+For each issue:
+1. **File:line** — exact location
+2. **Severity** — critical / warning / style
+3. **Category** — memory / thread / protocol / logic / error
+4. **Description** — what's wrong and how to fix it
+
+### Step 6: Output report
+
+Print a formatted summary:
+
+```
+=== PR REVIEW SUMMARY ===
+Branch: <branch-name>
+Files reviewed: <count>
+Issues found: <count>
+
+CRITICAL: <count>
+WARNING: <count>
+STYLE: <count>
+
+=== ISSUES ===
+[1] src/shared/compression.c:42 — CRITICAL (memory)
+    Potential leak: data returned from data_compress() not freed on error path
+    Fix: Add data_destroy(compressed) before return false
+
+...
+
+=== VERDICT ===
+[PASS] No critical issues found
+  — or —
+[FAIL] <N> critical issues must be fixed before merge
+```
+
+### Step 7: Optional PR comment
+
+If the user wants to post the review as a PR comment:
+```bash
+tea pr comment <number> --comment "<review report>"
+```
+
+## Rules
+- Do NOT edit any source files
+- Do NOT run builds or tests
+- Do NOT commit or push
+- Report ALL issues — don't filter or minimize
+- Be specific about line numbers and fix suggestions

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 4.1)
+cmake_minimum_required(VERSION 3.22)
 
 project(FastFileTransfer)
 

Dockerfile

@@ -0,0 +1,6 @@
+FROM ubuntu:24.04
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc g++ make libc6-dev cmake libzstd-dev libssl-dev git ca-certificates curl && \
+    curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
+    apt-get install -y --no-install-recommends nodejs && \
+    rm -rf /var/lib/apt/lists/*

shell.nix

@@ -8,6 +8,7 @@ pkgs.mkShell {
     cmake
     gnumake
     pkg-config
+    docker
     tea
   ];
 

src/client/client_cli.c

@@ -1,8 +1,11 @@
 #include "client_send.h"
 #include "config.h"
 #include "log.h"
+#include "protocol.h"
 #include "transport_tls.h"
 #include "utils.h"
+#include <errno.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -32,6 +35,7 @@ static void print_usage(void) {
   printf("  --include <pattern> Only include files matching pattern\n");
   printf("  --max-size <n>      Skip files larger than n bytes\n");
   printf("  --min-size <n>      Skip files smaller than n bytes\n");
+  printf("  --incremental       Skip files unchanged since last transfer\n");
   printf("  -m                  Enable multithreading\n");
   printf("  -s                  Enable chunk serialization\n");
   printf("  -f                  Enable sendfile (TCP only, not with -c or -s)\n");
@@ -43,6 +47,7 @@ static void print_usage(void) {
   printf("  --save-to-disk      Write received files to disk\n");
   printf("  --server-host <ip>  Server IP address (default: 127.0.0.1)\n");
   printf("  --server-port <n>   Server port (default: 8080)\n");
+  printf("  --bwlimit <KB/s>    Bandwidth limit in kilobytes per second\n");
   printf("  --tls               Enable TLS encryption\n");
   printf("  --cert <path>       TLS certificate file (PEM)\n");
   printf("  --key <path>        TLS private key file (PEM)\n");
@@ -94,6 +99,8 @@ int main(int argc, char *argv[]) {
       config->max_size = strtoull(argv[++i], NULL, 10);
     } else if (strcmp(argv[i], "--min-size") == 0 && i + 1 < argc) {
       config->min_size = strtoull(argv[++i], NULL, 10);
+    } else if (strcmp(argv[i], "--incremental") == 0) {
+      config->use_incremental = true;
     } else if (strcmp(argv[i], "-c") == 0 || strcmp(argv[i], "-z") == 0) {
       config->use_compression = true;
       log_message(LOG_LEVEL_INFO, "Enabled Compression");
@@ -132,6 +139,20 @@ int main(int argc, char *argv[]) {
       server_host = str_dup(argv[++i]);
     } else if (strcmp(argv[i], "--server-port") == 0 && i + 1 < argc) {
       server_port = atoi(argv[++i]);
+    } else if (strcmp(argv[i], "--bwlimit") == 0 && i + 1 < argc) {
+      char *end;
+      errno = 0;
+      unsigned long long kbps = strtoull(argv[++i], &end, 10);
+      if (errno != 0 || *end != '\0' || kbps == 0) {
+        fprintf(stderr, "Error: --bwlimit must be a positive integer\n");
+        return 1;
+      }
+      if (kbps > ULLONG_MAX / 1024) {
+        fprintf(stderr, "Error: --bwlimit value too large\n");
+        return 1;
+      }
+      io_set_bwlimit(kbps * 1024);
+      log_message(LOG_LEVEL_INFO, "Set bandwidth limit to %llu KB/s", kbps);
     } else if (strcmp(argv[i], "--progress") == 0) {
       config->show_progress = true;
     } else if (strcmp(argv[i], "--chunk-size") == 0 && i + 1 < argc) {
@@ -200,6 +221,16 @@ int main(int argc, char *argv[]) {
     return 1;
   }
 
+  if (config->use_incremental && config->use_chunk_serialization) {
+    fprintf(stderr, "Error: --incremental is not supported with -s (chunk serialization)\n");
+    return 1;
+  }
+
+  if (config->use_incremental && !config->use_metadata) {
+    log_message(LOG_LEVEL_INFO, "Enabling metadata preservation for --incremental");
+    config->use_metadata = true;
+  }
+
   if (config->use_tls) {
     if (!config->tls_cert || !config->tls_key) {
       fprintf(stderr, "Error: --tls requires --cert and --key\n");

src/client/client_send.c

@@ -19,6 +19,27 @@
 #include <threads.h>
 #include <time.h>
 
+static int incremental_check(Client *client, File *file) {
+  if (!send_status(client->file_descriptor, STATUS_CHECK)) return -1;
+  if (!send_str(client->file_descriptor, file->path)) return -1;
+  unsigned long long fsize = file->data->size;
+  long long mtime = file->metadata ? file->metadata->mtime_sec : 0;
+  if (!send_n_data(client->file_descriptor, &fsize, sizeof(fsize))) return -1;
+  if (!send_n_data(client->file_descriptor, &mtime, sizeof(mtime))) return -1;
+  Status s;
+  if (!receive_status(client->file_descriptor, &s)) return -1;
+  if (s == STATUS_ERROR) {
+    log_message(LOG_LEVEL_ERROR, "Server reported error for file");
+    return -1;
+  }
+  if (s == STATUS_OK) return 1;
+  if (s != STATUS_NEXT) {
+    log_message(LOG_LEVEL_ERROR, "Unexpected server status");
+    return -1;
+  }
+  return 0;
+}
+
 int send_chunk(Client *client, Chunk *chunk, Config *config) {
   if (config->use_chunk_serialization) {
     if (!send_status(client->file_descriptor, STATUS_CHUNK)) return -1;
@@ -33,17 +54,37 @@ int send_chunk(Client *client, Chunk *chunk, Config *config) {
     data_destroy(data);
   } else if (config->use_sendfile && !config->use_compression) {
     for (int i = 0; i < chunk->element_count; i++) {
-      if (!send_status(client->file_descriptor, STATUS_NEXT)) return -1;
-      if (!file_send_sendfile(chunk->items[i], client->file_descriptor, config->use_metadata))
-        return -1;
+      if (config->use_incremental) {
+        int rc = incremental_check(client, chunk->items[i]);
+        if (rc < 0) return -1;
+        if (rc > 0) continue;
+        if (!file_send_sendfile(chunk->items[i], client->file_descriptor, config->use_metadata, false))
+          return -1;
+      } else {
+        if (!send_status(client->file_descriptor, STATUS_NEXT)) return -1;
+        if (!file_send_sendfile(chunk->items[i], client->file_descriptor, config->use_metadata, true))
+          return -1;
+      }
     }
   } else {
     for (int i = 0; i < chunk->element_count; i++) {
-      if (!send_status(client->file_descriptor, STATUS_NEXT)) return -1;
-      if (!file_send_single_calls(chunk->items[i], client->file_descriptor,
-                            config->use_metadata,
-                            config->use_compression ? config->compression_level : 0))
-        return -1;
+      if (config->use_incremental) {
+        int rc = incremental_check(client, chunk->items[i]);
+        if (rc < 0) return -1;
+        if (rc > 0) continue;
+        if (!file_send_single_calls(chunk->items[i], client->file_descriptor,
+                                   config->use_metadata,
+                                   config->use_compression ? config->compression_level : 0,
+                                   false))
+          return -1;
+      } else {
+        if (!send_status(client->file_descriptor, STATUS_NEXT)) return -1;
+        if (!file_send_single_calls(chunk->items[i], client->file_descriptor,
+                               config->use_metadata,
+                               config->use_compression ? config->compression_level : 0,
+                               true))
+          return -1;
+      }
     }
   }
   return 0;

src/server/server.c

@@ -1,11 +1,9 @@
 #include "array_list.h"
 #include "chunk.h"
-#include "compression.h"
 #include "config.h"
 #include "data.h"
 #include "file.h"
 #include "log.h"
-#include "metadata.h"
 #include "multiprocessing.h"
 #include "protocol.h"
 #include "queue.h"
@@ -18,89 +16,57 @@
 #include <stdlib.h>
 #include <string.h>
 
-int receive_files(Config *config, int file_descriptor) {
+int receive_files(Config *config, int fd) {
   Status status;
-  if (!receive_status(file_descriptor, &status)) return -1;
-  while (status == STATUS_NEXT || status == STATUS_CHUNK) {
-    if (status == STATUS_CHUNK) {
-      Data *chunk_data = receive_data(file_descriptor);
-      if (chunk_data == NULL) {
-        log_message(LOG_LEVEL_ERROR, "Failed to receive chunk data");
-        send_status(file_descriptor, STATUS_ERROR);
-        return -1;
-      }
-      Data *data_to_process = chunk_data;
-      if (config->use_compression) {
-        data_to_process = data_decompress(chunk_data);
-        data_destroy(chunk_data);
-        if (data_to_process == NULL) {
-          log_message(LOG_LEVEL_ERROR, "Failed to decompress chunk");
-          send_status(file_descriptor, STATUS_ERROR);
-          return -1;
-        }
-      }
-      Chunk *chunk = chunk_deserialize(data_to_process, config->use_metadata);
-      data_destroy(data_to_process);
-      if (chunk == NULL) {
-        log_message(LOG_LEVEL_ERROR, "Failed to deserialize chunk, skipping");
-        send_status(file_descriptor, STATUS_ERROR);
-        return -1;
-      }
+  if (!receive_status(fd, &status)) return -1;
 
+  while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK) {
+    if (status == STATUS_CHECK) {
+      bool skipped;
+      File *file = receive_incremental_check(fd, config, &skipped);
+      if (skipped) goto next;
+      if (file == NULL && !skipped) return -1;
+      if (config->save_to_disk)
+        file_save_to_disk(config->receive_root_directory, file);
+      file_destroy(file);
+    } else if (status == STATUS_CHUNK) {
+      Chunk *chunk = receive_chunk_data(fd, config);
+      if (chunk == NULL) {
+        send_status(fd, STATUS_ERROR);
+        return -1;
+      }
       for (int i = 0; i < chunk->element_count; i++) {
-        if (config->save_to_disk) {
-          char *disk_path = path_cat(config->receive_root_directory, chunk->items[i]->path);
-          if (disk_path) {
-            to_disk(disk_path, chunk->items[i]->data->data, chunk->items[i]->data->size);
-            file_restore_metadata(disk_path, chunk->items[i]->metadata);
-            free(disk_path);
-          }
-        }
+        if (config->save_to_disk)
+          file_save_to_disk(config->receive_root_directory, chunk->items[i]);
       }
       chunk_destroy(chunk);
     } else {
-      File *file = file_receive(config, file_descriptor);
+      File *file = file_receive(config, fd);
       if (file == NULL) {
         log_message(LOG_LEVEL_ERROR, "Failed to receive file");
-        send_status(file_descriptor, STATUS_ERROR);
+        send_status(fd, STATUS_ERROR);
         return -1;
       }
-      if (config->save_to_disk) {
-        char *disk_path = path_cat(config->receive_root_directory, file->path);
-        if (disk_path) {
-          to_disk(disk_path, file->data->data, file->data->size);
-          file_restore_metadata(disk_path, file->metadata);
-          free(disk_path);
-        }
-      }
+      if (config->save_to_disk)
+        file_save_to_disk(config->receive_root_directory, file);
       file_destroy(file);
     }
-    if (!receive_status(file_descriptor, &status)) {
-      send_status(file_descriptor, STATUS_ERROR);
+  next:
+    if (!receive_status(fd, &status)) {
+      send_status(fd, STATUS_ERROR);
       return -1;
     }
   }
+
   if (status == STATUS_MANIFEST) {
-    int count;
-    if (!receive_int(file_descriptor, &count)) return -1;
-    ArrayList *manifest = array_list_create(free);
-    if (manifest) {
-      for (int i = 0; i < count; i++) {
-        char *s = receive_str(file_descriptor);
-        if (s) array_list_add(manifest, s);
-      }
-      fprintf(stderr, "Deleting files not in manifest...\n");
-      delete_extras(config->receive_root_directory, manifest);
-      array_list_delete(manifest);
-    }
-    if (!receive_status(file_descriptor, &status)) return -1;
+    if (receive_manifest(fd, config, &status) != 0) return -1;
   }
   if (status != STATUS_FINISHED) {
     log_message(LOG_LEVEL_ERROR, "Did not receive FINISHED Status");
-    send_status(file_descriptor, STATUS_ERROR);
+    send_status(fd, STATUS_ERROR);
     return -1;
   }
-  send_status(file_descriptor, STATUS_OK);
+  send_status(fd, STATUS_OK);
   return 0;
 }
 

src/shared/chunk.c

@@ -10,6 +10,7 @@
 #include "file.h"
 #include "log.h"
 #include "metadata.h"
+#include "protocol.h"
 
 Chunk *chunk_create(File **items, int element_count) {
   Chunk *chunk = (Chunk *)malloc(sizeof(Chunk));
@@ -178,5 +179,27 @@ Data *chunk_compress(Chunk *chunk, int compression_level, bool use_metadata) {
   return compressed;
 }
 
+Chunk *receive_chunk_data(int fd, Config *config) {
+  Data *chunk_data = receive_data(fd);
+  if (chunk_data == NULL) {
+    log_message(LOG_LEVEL_ERROR, "Failed to receive chunk data");
+    return NULL;
+  }
+  Data *data_to_process = chunk_data;
+  if (config->use_compression) {
+    data_to_process = data_decompress(chunk_data);
+    data_destroy(chunk_data);
+    if (data_to_process == NULL) {
+      log_message(LOG_LEVEL_ERROR, "Failed to decompress chunk");
+      return NULL;
+    }
+  }
+  Chunk *chunk = chunk_deserialize(data_to_process, config->use_metadata);
+  data_destroy(data_to_process);
+  if (chunk == NULL)
+    log_message(LOG_LEVEL_ERROR, "Failed to deserialize chunk, skipping");
+  return chunk;
+}
+
 
 

src/shared/chunk.h

@@ -1,6 +1,7 @@
 #ifndef CHUNK_H
 #define CHUNK_H
 
+#include "config.h"
 #include "data.h"
 #include "file.h"
 #include <stdbool.h>
@@ -18,5 +19,6 @@ void chunk_destroy(void *chunk);
 Data *chunk_serialize(Chunk *chunk, bool use_metadata);
 Chunk *chunk_deserialize(Data *data, bool use_metadata);
 Data *chunk_compress(Chunk *chunk, int compression_level, bool use_metadata);
+Chunk *receive_chunk_data(int fd, Config *config);
 
 #endif

src/shared/config.c

@@ -38,6 +38,7 @@ Config *config_create(char *version, char *send_directory,
   config->include_count = 0;
   config->max_size = 0;
   config->min_size = 0;
+  config->use_incremental = false;
   config->use_tls = false;
   config->tls_cert = NULL;
   config->tls_key = NULL;
@@ -96,6 +97,7 @@ bool config_send(int file_descriptor, Config *config) {
   if (!send_int(file_descriptor, (int)config->chunk_size)) return false;
   if (!send_int(file_descriptor, config->use_sendfile)) return false;
   if (!send_int(file_descriptor, config->use_delete)) return false;
+  if (!send_int(file_descriptor, config->use_incremental)) return false;
   Status status;
   if (!receive_status(file_descriptor, &status)) return false;
   if (status != STATUS_OK) {
@@ -141,6 +143,8 @@ Config *config_receive(int file_descriptor) {
   config->use_sendfile = tmp;
   if (!receive_int(file_descriptor, &tmp)) goto error;
   config->use_delete = tmp;
+  if (!receive_int(file_descriptor, &tmp)) goto error;
+  config->use_incremental = tmp;
   config->show_progress = false;
   config->dry_run = false;
   config->ssh_port = 22;

src/shared/config.h

@@ -32,13 +32,14 @@ typedef struct Config {
   int include_count;
   unsigned long long max_size;
   unsigned long long min_size;
+  bool use_incremental;
   bool use_tls;
   char *tls_cert;
   char *tls_key;
   char *tls_ca;
 } Config;
 
-#define PROTOCOL_VERSION "1.0.0"
+#define PROTOCOL_VERSION "1.1.0"
 #define DEFAULT_CHUNK_SIZE (10 * 1024 * 1024)
 
 Config *config_create(char *version, char *send_directory,

src/shared/file.c

@@ -96,26 +96,103 @@ bool file_load_data(File *file) {
   return true;
 }
 
-bool file_send_single_calls(File *file, int file_descriptor, bool use_metadata, int compression_level) {
+bool file_send_single_calls(File *file, int file_descriptor, bool use_metadata, int compression_level, bool send_path) {
+  Data *data_to_send = file->data;
+  Data *compressed_data = NULL;
   if (compression_level > 0) {
-    Data *compressed_data = data_compress(file->data, compression_level);
+    compressed_data = data_compress(file->data, compression_level);
     if (compressed_data == NULL) {
       log_message(LOG_LEVEL_ERROR, "Failed to compress file data");
       return false;
     }
-    data_destroy(file->data);
-    if (compressed_data == NULL) {
-      log_message(LOG_LEVEL_ERROR, "Compression failed in file_send_single_calls");
-      exit(EXIT_FAILURE);
-    }
-    file->data = compressed_data;
+    data_to_send = compressed_data;
   }
-  if (!send_str(file_descriptor, file->path)) return false;
-  if (use_metadata && !metadata_send(file_descriptor, file->metadata)) return false;
-  if (!send_data(file_descriptor, file->data)) return false;
+  if (send_path && !send_str(file_descriptor, file->path)) {
+    data_destroy(compressed_data);
+    return false;
+  }
+  if (use_metadata && !metadata_send(file_descriptor, file->metadata)) {
+    data_destroy(compressed_data);
+    return false;
+  }
+  if (!send_data(file_descriptor, data_to_send)) {
+    data_destroy(compressed_data);
+    return false;
+  }
+  data_destroy(compressed_data);
   return true;
 }
 
+bool file_save_to_disk(const char *root_directory, File *file) {
+  char *disk_path = path_cat((char *)root_directory, file->path);
+  if (disk_path == NULL) return false;
+  bool ok = to_disk(disk_path, file->data->data, file->data->size);
+  if (ok) file_restore_metadata(disk_path, file->metadata);
+  free(disk_path);
+  return ok;
+}
+
+File *receive_incremental_check(int fd, Config *config, bool *skipped) {  *skipped = false;
+  char *check_path = receive_str(fd);
+  if (check_path == NULL) { send_status(fd, STATUS_ERROR); return NULL; }
+
+  unsigned long long check_size;
+  long long check_mtime;
+  if (!receive_n_data(fd, &check_size, sizeof(check_size)) ||
+      !receive_n_data(fd, &check_mtime, sizeof(check_mtime))) {
+    free(check_path);
+    send_status(fd, STATUS_ERROR);
+    return NULL;
+  }
+
+  char *full_path = path_cat(config->receive_root_directory, check_path);
+  struct stat st;
+  bool match = false;
+  if (full_path && stat(full_path, &st) == 0 &&
+      (unsigned long long)st.st_size == check_size &&
+      (long long)st.st_mtime == check_mtime) {
+    match = true;
+  }
+  free(full_path);
+
+  if (match) {
+    if (!send_status(fd, STATUS_OK)) { free(check_path); return NULL; }
+    free(check_path);
+    *skipped = true;
+    return NULL;
+  }
+
+  if (!send_status(fd, STATUS_NEXT)) { free(check_path); return NULL; }
+
+  File *file = file_create(check_path);
+  free(check_path);
+  if (file == NULL) { send_status(fd, STATUS_ERROR); return NULL; }
+
+  if (config->use_metadata) {
+    int meta_ok = 1;
+    file->metadata = metadata_receive(fd, &meta_ok);
+    if (!meta_ok) { file_destroy(file); send_status(fd, STATUS_ERROR); return NULL; }
+  }
+
+  Data *file_data = receive_data(fd);
+  if (file_data == NULL) {
+    file_destroy(file);
+    send_status(fd, STATUS_ERROR);
+    return NULL;
+  }
+
+  if (config->use_compression) {
+    Data *uncompressed = data_decompress(file_data);
+    data_destroy(file_data);
+    if (uncompressed == NULL) { file_destroy(file); send_status(fd, STATUS_ERROR); return NULL; }
+    file_data = uncompressed;
+  }
+
+  data_destroy(file->data);
+  file->data = file_data;
+  return file;
+}
+
 bool to_disk(const char *path, const void *data, unsigned long long data_size) {
   char *directory = str_dup(path);
   char *dir_to_free = directory;
@@ -141,8 +218,8 @@ bool to_disk(const char *path, const void *data, unsigned long long data_size) {
   return true;
 }
 
-bool file_send_sendfile(File *file, int file_descriptor, bool use_metadata) {
-  if (!send_str(file_descriptor, file->path)) return false;
+bool file_send_sendfile(File *file, int file_descriptor, bool use_metadata, bool send_path) {
+  if (send_path && !send_str(file_descriptor, file->path)) return false;
   if (use_metadata && !metadata_send(file_descriptor, file->metadata)) return false;
 
   int fd = open(file->path, O_RDONLY);
@@ -178,7 +255,9 @@ File *file_receive(Config *config, int file_descriptor) {
   free(path);
   if (file == NULL) return NULL;
   if (config->use_metadata) {
-    file->metadata = metadata_receive(file_descriptor);
+    int meta_ok = 1;
+    file->metadata = metadata_receive(file_descriptor, &meta_ok);
+    if (!meta_ok) { file_destroy(file); return NULL; }
   }
   Data *file_data = receive_data(file_descriptor);
   if (file_data == NULL) {
@@ -216,4 +295,21 @@ size_t file_content_to_buffer(File *file) {
   return bytes_read;
 }
 
+int receive_manifest(int fd, Config *config, int *next_status) {
+  int count;
+  if (!receive_int(fd, &count)) return -1;
+  ArrayList *manifest = array_list_create(free);
+  if (manifest) {
+    for (int i = 0; i < count; i++) {
+      char *s = receive_str(fd);
+      if (s) array_list_add(manifest, s);
+    }
+    fprintf(stderr, "Deleting files not in manifest...\n");
+    delete_extras(config->receive_root_directory, manifest);
+    array_list_delete(manifest);
+  }
+  if (!receive_status(fd, next_status)) return -1;
+  return 0;
+}
+
 

src/shared/file.h

@@ -24,11 +24,14 @@ File *file_create(const char *path);
 void file_destroy(void *item);
 bool file_load_data(File *file);
 File *file_receive(Config *config, int file_descriptor);
-bool file_send_single_calls(File *file, int file_descriptor, bool use_metadata, int compression_level);
-bool file_send_sendfile(File *file, int file_descriptor, bool use_metadata);
+bool file_send_single_calls(File *file, int file_descriptor, bool use_metadata, int compression_level, bool send_path);
+bool file_send_sendfile(File *file, int file_descriptor, bool use_metadata, bool send_path);
 size_t file_content_to_buffer(File *file);
 FileMetadata *file_metadata_create(struct stat *stats);
 void file_metadata_destroy(void *metadata);
 bool to_disk(const char *path, const void *data, unsigned long long data_size);
+bool file_save_to_disk(const char *root_directory, File *file);
+File *receive_incremental_check(int fd, Config *config, bool *skipped);
+int receive_manifest(int fd, Config *config, int *next_status);
 
 #endif

src/shared/metadata.c

@@ -50,22 +50,28 @@ bool metadata_send(int file_descriptor, FileMetadata *m) {
          send_n_data(file_descriptor, &m->mtime_nsec, sizeof(long));
 }
 
-FileMetadata *metadata_receive(int file_descriptor) {
+FileMetadata *metadata_receive(int file_descriptor, int *ok) {
   int present;
-  if (!receive_n_data(file_descriptor, &present, sizeof(int)))
+  if (!receive_n_data(file_descriptor, &present, sizeof(int))) {
+    if (ok) *ok = 0;
     return NULL;
-  if (!present)
+  }
+  if (!present) {
+    if (ok) *ok = 1;
     return NULL;
+  }
   FileMetadata *m = malloc(sizeof(FileMetadata));
-  if (m == NULL) return NULL;
+  if (m == NULL) { if (ok) *ok = 0; return NULL; }
   if (!receive_n_data(file_descriptor, &m->mode, sizeof(mode_t)) ||
       !receive_n_data(file_descriptor, &m->uid, sizeof(uid_t)) ||
       !receive_n_data(file_descriptor, &m->gid, sizeof(gid_t)) ||
       !receive_n_data(file_descriptor, &m->mtime_sec, sizeof(time_t)) ||
       !receive_n_data(file_descriptor, &m->mtime_nsec, sizeof(long))) {
     free(m);
+    if (ok) *ok = 0;
     return NULL;
   }
+  if (ok) *ok = 1;
   return m;
 }
 

src/shared/metadata.h

@@ -10,7 +10,7 @@
 void metadata_to_buf(char **buf, FileMetadata *m);
 FileMetadata *metadata_from_buf(char **buf);
 bool metadata_send(int file_descriptor, FileMetadata *m);
-FileMetadata *metadata_receive(int file_descriptor);
+FileMetadata *metadata_receive(int file_descriptor, int *ok);
 void file_restore_metadata(const char *path, FileMetadata *metadata);
 
 #endif

src/shared/multiprocessing.c

@@ -1,12 +1,10 @@
 #include "multiprocessing.h"
 #include "array_list.h"
 #include "chunk.h"
-#include "compression.h"
 #include "config.h"
 #include "data.h"
 #include "file.h"
 #include "log.h"
-#include "metadata.h"
 #include "protocol.h"
 #include "queue.h"
 #include "utils.h"
@@ -85,26 +83,8 @@ void pipeline_context_receiver_destroy(PipelineContextReceiver *context) {
 
 static void receive_chunk_enqueue(int file_descriptor,
                                   PipelineContextReceiver *context) {
-  Data *chunk_data = receive_data(file_descriptor);
-  if (chunk_data == NULL) {
-    log_message(LOG_LEVEL_ERROR, "Failed to receive chunk data");
-    return;
-  }
-  Data *data_to_process = chunk_data;
-  if (context->config->use_compression) {
-    data_to_process = data_decompress(chunk_data);
-    data_destroy(chunk_data);
-    if (data_to_process == NULL) {
-      log_message(LOG_LEVEL_ERROR, "Failed to decompress chunk");
-      return;
-    }
-  }
-  Chunk *chunk = chunk_deserialize(data_to_process, context->config->use_metadata);
-  data_destroy(data_to_process);
-  if (chunk == NULL) {
-    log_message(LOG_LEVEL_ERROR, "Failed to deserialize chunk, skipping");
-    return;
-  }
+  Chunk *chunk = receive_chunk_data(file_descriptor, context->config);
+  if (chunk == NULL) return;
 
   for (int i = 0; i < chunk->element_count; i++) {
     File *file = chunk->items[i];
@@ -126,8 +106,17 @@ int receive_thread(void *pipeline_context) {
 
   Status status;
   if (!receive_status(file_descriptor, &status)) return thrd_error;
-  while (status == STATUS_NEXT || status == STATUS_CHUNK) {
-    if (status == STATUS_CHUNK) {
+  while (status == STATUS_NEXT || status == STATUS_CHUNK || status == STATUS_CHECK) {
+    if (status == STATUS_CHECK) {
+      bool skipped;
+      File *file = receive_incremental_check(file_descriptor, config, &skipped);
+      if (!skipped) {
+        if (file == NULL) return thrd_error;
+        queue_enqueue_multithreaded(context->queue, file, &context->mutex,
+                                    &context->condition_not_empty,
+                                    &context->condition_not_full);
+      }
+    } else if (status == STATUS_CHUNK) {
       receive_chunk_enqueue(file_descriptor, context);
     } else {
       File *file = file_receive(config, file_descriptor);
@@ -142,22 +131,7 @@ int receive_thread(void *pipeline_context) {
     if (!receive_status(file_descriptor, &status)) return thrd_error;
   }
   if (status == STATUS_MANIFEST) {
-    int count;
-    if (!receive_int(file_descriptor, &count)) return thrd_error;
-    ArrayList *manifest = array_list_create(free);
-    if (manifest) {
-      for (int i = 0; i < count; i++) {
-        char *s = receive_str(file_descriptor);
-        if (s) {
-          array_list_add(manifest, s);
-        }
-      }
-      delete_extras(context->config->receive_root_directory, manifest);
-      for (int i = 0; i < manifest->size; i++)
-        free(manifest->items[i]);
-      array_list_delete(manifest);
-    }
-    if (!receive_status(file_descriptor, &status)) return thrd_error;
+    if (receive_manifest(file_descriptor, config, &status) != 0) return thrd_error;
   }
   mtx_lock(&context->mutex);
   context->receiver_done = true;
@@ -182,14 +156,8 @@ int write_thread(void *pipeline_context) {
       free(root_directory);
       return thrd_success;
     }
-    if (save_to_disk) {
-      char *disk_path = path_cat(root_directory, file->path);
-      if (disk_path) {
-        to_disk(disk_path, file->data->data, file->data->size);
-        file_restore_metadata(disk_path, file->metadata);
-        free(disk_path);
-      }
-    }
+    if (save_to_disk)
+      file_save_to_disk(root_directory, file);
     file_destroy(file);
   }
 }

src/shared/protocol.c

@@ -1,20 +1,61 @@
 #include "protocol.h"
 #include "log.h"
+#include <errno.h>
 #include <openssl/ssl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <unistd.h>
 
 static __thread int io_read_fd = -1;
 static __thread int io_write_fd = -1;
 static SSL *io_ssl = NULL;
 
+static unsigned long long io_bwlimit = 0;
+static long long bw_tokens = 0;
+static struct timespec bw_last_refill = {0, 0};
+
 void io_set_fds(int read_fd, int write_fd) {
   io_read_fd = read_fd;
   io_write_fd = write_fd;
 }
 
+void io_set_bwlimit(unsigned long long bytes_per_sec) {
+  io_bwlimit = bytes_per_sec;
+  bw_tokens = (long long)io_bwlimit;
+  clock_gettime(CLOCK_MONOTONIC, &bw_last_refill);
+}
+
+static void bw_throttle(size_t bytes_written) {
+  if (io_bwlimit == 0) return;
+
+  struct timespec now;
+  clock_gettime(CLOCK_MONOTONIC, &now);
+
+  long long elapsed_ns = (now.tv_sec - bw_last_refill.tv_sec) * 1000000000LL +
+                         (now.tv_nsec - bw_last_refill.tv_nsec);
+  bw_last_refill = now;
+
+  long long tokens_to_add = (long long)((double)io_bwlimit * elapsed_ns / 1000000000.0);
+  bw_tokens += tokens_to_add;
+  if (bw_tokens > (long long)io_bwlimit)
+    bw_tokens = (long long)io_bwlimit;
+
+  bw_tokens -= (long long)bytes_written;
+
+  if (bw_tokens < 0) {
+    long long deficit_ns = (long long)((double)(-bw_tokens) / io_bwlimit * 1000000000.0);
+    struct timespec sleep_time, remaining;
+    sleep_time.tv_sec = deficit_ns / 1000000000LL;
+    sleep_time.tv_nsec = deficit_ns % 1000000000LL;
+    while (nanosleep(&sleep_time, &remaining) < 0 && errno == EINTR)
+      sleep_time = remaining;
+    bw_tokens = 0;
+    clock_gettime(CLOCK_MONOTONIC, &bw_last_refill);
+  }
+}
+
 void io_set_ssl(SSL *ssl) {
   io_ssl = ssl;
 }
@@ -28,17 +69,19 @@ bool send_n_data(int file_descriptor, void *data, size_t data_size) {
   int fd = io_fd(io_write_fd, file_descriptor);
   ssize_t total_bytes_send = 0;
   while (total_bytes_send < data_size) {
+    size_t chunk = data_size - total_bytes_send;
+    if (io_bwlimit > 0 && chunk > 65536)
+      chunk = 65536;
     ssize_t bytes_send;
     if (io_ssl)
-      bytes_send = SSL_write(io_ssl, (char *)data + total_bytes_send,
-                             data_size - total_bytes_send);
+      bytes_send = SSL_write(io_ssl, (char *)data + total_bytes_send, chunk);
     else
-      bytes_send = write(fd, (char *)data + total_bytes_send,
-                          data_size - total_bytes_send);
+      bytes_send = write(fd, (char *)data + total_bytes_send, chunk);
     if (bytes_send <= 0) {
       log_message(LOG_LEVEL_ERROR, "Could not send data");
       return false;
     }
+    bw_throttle((size_t)bytes_send);
     total_bytes_send += bytes_send;
   }
   log_message(LOG_LEVEL_DEBUG, "    Send n Data: %zu", total_bytes_send);
@@ -82,6 +125,8 @@ static const char *status_to_string(Status status) {
     return "NEXT";
   case STATUS_CHUNK:
     return "CHUNK";
+  case STATUS_CHECK:
+    return "CHECK";
   default:
     return "UNKNOWN";
   }

src/shared/protocol.h

@@ -8,9 +8,11 @@
 typedef struct ssl_st SSL;
 
 typedef int Status;
-enum NET_STATUS { STATUS_OK, STATUS_ERROR, STATUS_FINISHED, STATUS_NEXT, STATUS_CHUNK, STATUS_MANIFEST };
+enum NET_STATUS { STATUS_OK, STATUS_ERROR, STATUS_FINISHED, STATUS_NEXT, STATUS_CHUNK, STATUS_MANIFEST, STATUS_CHECK };
 
 void io_set_fds(int read_fd, int write_fd);
+void io_set_bwlimit(unsigned long long bytes_per_sec);
+typedef struct ssl_st SSL;
 void io_set_ssl(SSL *ssl);
 bool send_n_data(int file_descriptor, void *data, size_t data_size);
 bool receive_n_data(int file_descriptor, void *data, size_t data_size);

src/shared/transport_ssh.c

@@ -143,5 +143,7 @@ Client *client_connect_ssh(char *destination, int port) {
   client->address.sin_family = AF_UNIX;
   client->address_length = 0;
   client->ssh_child_pid = pid;
+  client->ssl = NULL;
+  client->ssl_ctx = NULL;
   return client;
 }

test.py

@@ -50,7 +50,7 @@ CLIENT_CMD_PREFIX = [
 
 BASE_CLIENT_FLAGS = ["--save-to-disk"]
 
-TEST_CASES = [
+TEST_CASES_FULL = [
     {"name": "Standard", "flags": []},
     {"name": "Posix Args (no flags)", "flags": [], "posix": True},
     {"name": "Standard (no metadata)", "flags": [], "use_metadata": False},
@@ -68,7 +68,14 @@ TEST_CASES = [
     {"name": "Sendfile + Multithreading (-f -m)", "flags": ["-f", "-m"]},
 ]
 
-SSH_CASES = [
+TEST_CASES_LIGHT = [
+    {"name": "Standard", "flags": []},
+    {"name": "Compression (-c)", "flags": ["-c"]},
+    {"name": "Chunk Serialization (-s)", "flags": ["-s"]},
+    {"name": "Multithreading + Compression + Chunk Serialization (-m -c -s)", "flags": ["-m", "-c", "-s"]},
+]
+
+SSH_CASES_FULL = [
     {"name": "SSH (localhost)", "flags": []},
     {"name": "SSH Multithreading (-m)", "flags": ["-m"]},
     {"name": "SSH Compression (-c)", "flags": ["-c"]},
@@ -79,11 +86,17 @@ SSH_CASES = [
     {"name": "SSH Multithreading + Compression + Chunk Serialization (-m -c -s)", "flags": ["-m", "-c", "-s"]},
 ]
 
-RSYNC_CASES = [
+SSH_CASES_LIGHT = [
+    {"name": "SSH (localhost)", "flags": []},
+]
+
+RSYNC_CASES_FULL = [
     {"name": "rsync (archive)", "args": ["-aH"]},
     {"name": "rsync (archive + compress)", "args": ["-aHz"]},
 ]
 
+RSYNC_CASES_LIGHT = []
+
 
 def netem_apply(profile):
     params = NETWORK_PROFILES[profile]
@@ -119,12 +132,12 @@ def find_free_port():
         return s.getsockname()[1]
 
 
-def generate_test_files(source_dir):
+def generate_test_files(source_dir, full=False):
     if os.path.exists(source_dir):
         shutil.rmtree(source_dir)
     os.makedirs(source_dir)
 
-    target_total = 25 * 1024 * 1024
+    target_total = 25 * 1024 * 1024 if full else 0
     written = 0
 
     files = {
@@ -141,14 +154,15 @@ def generate_test_files(source_dir):
             f.write(content)
         written += len(content)
 
-    os.makedirs(os.path.join(source_dir, "bulk"), exist_ok=True)
-    i = 0
-    while written < target_total:
-        chunk_size = min(5 * 1024 * 1024, target_total - written)
-        with open(os.path.join(source_dir, f"bulk/file_{i}.dat"), "wb") as f:
-            f.write(random.randbytes(chunk_size))
-        written += chunk_size
-        i += 1
+    if full:
+        os.makedirs(os.path.join(source_dir, "bulk"), exist_ok=True)
+        i = 0
+        while written < target_total:
+            chunk_size = min(5 * 1024 * 1024, target_total - written)
+            with open(os.path.join(source_dir, f"bulk/file_{i}.dat"), "wb") as f:
+                f.write(random.randbytes(chunk_size))
+            written += chunk_size
+            i += 1
 
     total_mb = written / (1024 * 1024)
     small_bytes = sum(len(c) for c in files.values())
@@ -254,19 +268,24 @@ def print_profile_header(profile_name):
         print("  No limits applied")
 
 
-def run_profile(profile_name, source_dir, dest_dir):
+def run_profile(profile_name, source_dir, dest_dir, *, full=False, test_cases=None, ssh_cases=None, rsync_cases=None):
     print_profile_header(profile_name)
     is_limited = profile_name != "Unlimited"
     client_prefix = CLIENT_CMD_PREFIX if is_limited else []
 
+    if test_cases is None:
+        test_cases = TEST_CASES_FULL if full else TEST_CASES_LIGHT
+    if ssh_cases is None:
+        ssh_cases = SSH_CASES_FULL if full else SSH_CASES_LIGHT
+    if rsync_cases is None:
+        rsync_cases = RSYNC_CASES_FULL if full else RSYNC_CASES_LIGHT
+
     try:
-        if is_limited:
+        if is_limited and full:
             netem_apply(profile_name)
-        else:
-            netem_reset()
 
         results = []
-        for case in TEST_CASES:
+        for case in test_cases:
             flags = BASE_CLIENT_FLAGS + (["-M"] if case.get("use_metadata", True) else []) + case["flags"]
             if case.get("posix"):
                 cmd = client_prefix + BASE_CLIENT_CMD + [source_dir, dest_dir] + flags
@@ -281,7 +300,7 @@ def run_profile(profile_name, source_dir, dest_dir):
                 results.append({"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
 
         if SSH_AVAILABLE:
-            for case in SSH_CASES:
+            for case in ssh_cases:
                 flags = BASE_CLIENT_FLAGS + (["-M"] if case.get("use_metadata", True) else []) + case["flags"]
                 ssh_dest = f"localhost:{dest_dir}_ssh"
                 cmd = BASE_CLIENT_CMD + [source_dir, ssh_dest] + flags
@@ -293,182 +312,222 @@ def run_profile(profile_name, source_dir, dest_dir):
                 except Exception as e:
                     results.append({"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
     
-        port, conf, daemon = start_rsync_daemon(source_dir)
-        try:
-            for case in RSYNC_CASES:
-                cmd = client_prefix + ["rsync"] + case["args"] + [f"rsync://localhost:{port}/source/", f"{dest_dir}/"]
-                print(f"\n  --- {case['name']} ---\n    Running: {' '.join(cmd)}")
-                try:
-                    r = run_single_test(cmd, case["name"], source_dir, dest_dir, source_prefix="")
-                    r["suite"] = profile_name
-                except subprocess.TimeoutExpired:
-                    r = {"name": case["name"], "suite": profile_name, "status": "Timeout", "time": "N/A", "error": "Exceeded 120s"}
-                except Exception as e:
-                    r = {"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)}
-                else:
-                    if r["status"] != "Success" and client_prefix:
-                        tmp = tempfile.mkdtemp()
-                        try:
-                            plain = subprocess.run(["rsync", "-aH", f"rsync://localhost:{port}/source/", f"{tmp}/"], capture_output=True, text=True, timeout=30)
-                            if plain.returncode != 0:
-                                errs = [l for l in (plain.stderr or "").split("\n") if l.strip()]
-                                if errs:
-                                    r["error"] += f" | raw: {errs[-1][:150]}"
-                        finally:
-                            shutil.rmtree(tmp, ignore_errors=True)
-                results.append(r)
-        finally:
-            wait_proc(daemon)
+        if rsync_cases:
+            port, conf, daemon = start_rsync_daemon(source_dir)
             try:
-                os.unlink(conf)
-            except Exception:
-                pass
+                for case in rsync_cases:
+                    cmd = client_prefix + ["rsync"] + case["args"] + [f"rsync://localhost:{port}/source/", f"{dest_dir}/"]
+                    print(f"\n  --- {case['name']} ---\n    Running: {' '.join(cmd)}")
+                    try:
+                        r = run_single_test(cmd, case["name"], source_dir, dest_dir, source_prefix="")
+                        r["suite"] = profile_name
+                    except subprocess.TimeoutExpired:
+                        r = {"name": case["name"], "suite": profile_name, "status": "Timeout", "time": "N/A", "error": "Exceeded 120s"}
+                    except Exception as e:
+                        r = {"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)}
+                    else:
+                        if r["status"] != "Success" and client_prefix:
+                            tmp = tempfile.mkdtemp()
+                            try:
+                                plain = subprocess.run(["rsync", "-aH", f"rsync://localhost:{port}/source/", f"{tmp}/"], capture_output=True, text=True, timeout=30)
+                                if plain.returncode != 0:
+                                    errs = [l for l in (plain.stderr or "").split("\n") if l.strip()]
+                                    if errs:
+                                        r["error"] += f" | raw: {errs[-1][:150]}"
+                            finally:
+                                shutil.rmtree(tmp, ignore_errors=True)
+                    results.append(r)
+            finally:
+                wait_proc(daemon)
+                try:
+                    os.unlink(conf)
+                except Exception:
+                    pass
 
-        # Feature-specific tests for rsync-compatible flags
-        print("\n  " + "─" * 56 + "\n  Feature Tests\n  " + "─" * 56)
+        if full:
+            # Feature-specific tests for rsync-compatible flags
+            print("\n  " + "─" * 56 + "\n  Feature Tests\n  " + "─" * 56)
 
-        # Dry run (-n) — no server needed
-        print("\n  --- Dry run (-n) ---")
-        flags = BASE_CLIENT_FLAGS + ["-n"]
-        cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags
-        print(f"    Running: {' '.join(cmd)}")
-        try:
-            start = time.monotonic()
-            result = subprocess.run(cmd, text=True, capture_output=True)
-            duration = time.monotonic() - start
-            r = {"name": "Dry run (-n)", "suite": profile_name}
-            if result.returncode == 0 and "Dry run:" in result.stdout:
-                r["status"] = "Success"
-                r["time"] = f"{duration:.4f}s"
-                r["error"] = ""
-            else:
-                r["status"] = "Failed"
-                r["time"] = "N/A"
-                r["error"] = f"Exit {result.returncode}: {(result.stderr or result.stdout)[:100]}"
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Dry run (-n)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
-
-        # Archive mode (-a)
-        feature_flags = BASE_CLIENT_FLAGS + ["-a"]
-        cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
-        print(f"\n  --- Archive mode (-a) ---\n    Running: {' '.join(cmd)}")
-        try:
-            r = run_single_test(cmd, "Archive mode (-a)", source_dir, dest_dir)
-            r["suite"] = profile_name
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Archive mode (-a)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
-
-        # Exclude (--exclude small.txt)
-        feature_flags = BASE_CLIENT_FLAGS + ["--exclude", "small.txt"]
-        cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
-        print(f"\n  --- Exclude (--exclude small.txt) ---\n    Running: {' '.join(cmd)}")
-        try:
-            r = run_single_test(cmd, "Exclude (--exclude small.txt)", source_dir, dest_dir,
-                                expected_missing=["small.txt"])
-            r["suite"] = profile_name
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Exclude (--exclude small.txt)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
-
-        # Progress (--progress)
-        feature_flags = BASE_CLIENT_FLAGS + ["--progress"]
-        cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
-        print(f"\n  --- Progress (--progress) ---\n    Running: {' '.join(cmd)}")
-        try:
-            r = run_single_test(cmd, "Progress (--progress)", source_dir, dest_dir)
-            r["suite"] = profile_name
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Progress (--progress)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
-
-        # Chunk size (--chunk-size 5242880)
-        feature_flags = BASE_CLIENT_FLAGS + ["--chunk-size", "5242880"]
-        cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
-        print(f"\n  --- Chunk size (--chunk-size 5242880) ---\n    Running: {' '.join(cmd)}")
-        try:
-            r = run_single_test(cmd, "Chunk size (--chunk-size 5242880)", source_dir, dest_dir)
-            r["suite"] = profile_name
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Chunk size (--chunk-size 5242880)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
-
-        # Delete (--delete) — pre-populate dest, add extra files, then sync with --delete
-        # Note: server handles one client per launch, so we restart between syncs
-        print(f"\n  --- Delete (--delete) ---")
-        try:
-            flags = BASE_CLIENT_FLAGS + ["-M"]
-            # First sync (no delete) to populate dest
-            s1 = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
-            time.sleep(0.5)
-            first_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags
-            r1 = subprocess.run(first_cmd, text=True, capture_output=True)
-            wait_proc(s1)
-            if r1.returncode != 0:
-                raise RuntimeError(f"First sync failed: {r1.stderr[:100]}")
-            # Add extra files to received dir
-            received = os.path.join(dest_dir, os.path.abspath(source_dir).lstrip(os.sep))
-            extra_path = os.path.join(received, "extra_file.txt")
-            with open(extra_path, "w") as f:
-                f.write("should be deleted")
-            extra_dir = os.path.join(received, "extra_dir")
-            os.makedirs(extra_dir, exist_ok=True)
-            with open(os.path.join(extra_dir, "nested.txt"), "w") as f:
-                f.write("nested extra")
-            # Second sync with --delete (fresh server)
-            s2 = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
-            time.sleep(0.5)
-            second_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags + ["--delete"]
-            start = time.monotonic()
-            r2 = subprocess.run(second_cmd, text=True, capture_output=True)
-            duration = time.monotonic() - start
-            wait_proc(s2)
-            r = {"name": "Delete (--delete)", "suite": profile_name}
-            if r2.returncode == 0 and not os.path.exists(extra_path) and not os.path.exists(extra_dir):
-                mismatches, missing = verify_transfer(source_dir, received)
-                if not mismatches and not missing:
+            # Dry run (-n) — no server needed
+            print("\n  --- Dry run (-n) ---")
+            flags = BASE_CLIENT_FLAGS + ["-n"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags
+            print(f"    Running: {' '.join(cmd)}")
+            try:
+                start = time.monotonic()
+                result = subprocess.run(cmd, text=True, capture_output=True)
+                duration = time.monotonic() - start
+                r = {"name": "Dry run (-n)", "suite": profile_name}
+                if result.returncode == 0 and "Dry run:" in result.stdout:
                     r["status"] = "Success"
                     r["time"] = f"{duration:.4f}s"
                     r["error"] = ""
                 else:
                     r["status"] = "Failed"
                     r["time"] = "N/A"
-                    r["error"] = f"post-delete verify: mismatches={len(mismatches)}, missing={len(missing)}"
-            else:
-                r["status"] = "Failed"
-                r["time"] = "N/A"
-                errs = []
-                if r2.returncode != 0:
-                    errs.append(f"Exit {r2.returncode}: {(r2.stderr or r2.stdout)[:60]}")
-                if os.path.exists(extra_path):
-                    errs.append("extra_file.txt remains")
-                if os.path.exists(extra_dir):
-                    errs.append("extra_dir remains")
-                r["error"] = " | ".join(errs)
-            results.append(r)
-        except Exception as e:
-            results.append({"name": "Delete (--delete)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+                    r["error"] = f"Exit {result.returncode}: {(result.stderr or result.stdout)[:100]}"
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Dry run (-n)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
 
-        # SSH feature tests
-        if SSH_AVAILABLE:
-            ssh_dest = f"localhost:{dest_dir}_ssh"
-            ssh_feature_cases = [
-                {"name": "SSH Archive (-a)", "flags": ["-a"]},
-                {"name": "SSH Exclude (--exclude small.txt)", "flags": ["--exclude", "small.txt"], "expected_missing": ["small.txt"]},
-            ]
-            for case in ssh_feature_cases:
-                flags = BASE_CLIENT_FLAGS + case["flags"]
-                cmd = BASE_CLIENT_CMD + [source_dir, ssh_dest] + flags
-                print(f"\n  --- {case['name']} ---\n    Running: {' '.join(cmd)}")
-                try:
-                    r = run_single_test(cmd, case["name"], source_dir, f"{dest_dir}_ssh",
-                                        no_server=True,
-                                        expected_missing=case.get("expected_missing"))
-                    r["suite"] = profile_name
-                    results.append(r)
-                except Exception as e:
-                    results.append({"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+            # Archive mode (-a)
+            feature_flags = BASE_CLIENT_FLAGS + ["-a"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
+            print(f"\n  --- Archive mode (-a) ---\n    Running: {' '.join(cmd)}")
+            try:
+                r = run_single_test(cmd, "Archive mode (-a)", source_dir, dest_dir)
+                r["suite"] = profile_name
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Archive mode (-a)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Exclude (--exclude small.txt)
+            feature_flags = BASE_CLIENT_FLAGS + ["--exclude", "small.txt"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
+            print(f"\n  --- Exclude (--exclude small.txt) ---\n    Running: {' '.join(cmd)}")
+            try:
+                r = run_single_test(cmd, "Exclude (--exclude small.txt)", source_dir, dest_dir,
+                                    expected_missing=["small.txt"])
+                r["suite"] = profile_name
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Exclude (--exclude small.txt)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Progress (--progress)
+            feature_flags = BASE_CLIENT_FLAGS + ["--progress"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
+            print(f"\n  --- Progress (--progress) ---\n    Running: {' '.join(cmd)}")
+            try:
+                r = run_single_test(cmd, "Progress (--progress)", source_dir, dest_dir)
+                r["suite"] = profile_name
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Progress (--progress)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Bandwidth limit (--bwlimit 10240 = 10 MB/s)
+            feature_flags = BASE_CLIENT_FLAGS + ["--bwlimit", "10240"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
+            print(f"\n  --- Bandwidth limit (--bwlimit 10240 KB/s) ---\n    Running: {' '.join(cmd)}")
+            try:
+                r = run_single_test(cmd, "Bandwidth limit (--bwlimit 10240)", source_dir, dest_dir)
+                r["suite"] = profile_name
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Bandwidth limit (--bwlimit 10240)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Incremental sync (--incremental) — first sync, then second sync should skip all
+            print(f"\n  --- Incremental (--incremental) ---")
+            try:
+                flags = BASE_CLIENT_FLAGS + ["-M"]
+                srv = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
+                time.sleep(0.5)
+                first_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags
+                r1 = subprocess.run(first_cmd, text=True, capture_output=True)
+                wait_proc(srv)
+                if r1.returncode != 0:
+                    raise RuntimeError(f"First sync failed: {r1.stderr[:100]}")
+                srv2 = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
+                time.sleep(0.5)
+                second_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags + ["--incremental"]
+                start = time.monotonic()
+                r2 = subprocess.run(second_cmd, text=True, capture_output=True, timeout=30)
+                duration = time.monotonic() - start
+                wait_proc(srv2)
+                r = {"name": "Incremental (--incremental)", "suite": profile_name,
+                     "status": "Success" if r2.returncode == 0 else "Failed",
+                     "time": f"{duration:.4f}s" if r2.returncode == 0 else "N/A",
+                     "error": "" if r2.returncode == 0 else f"Exit {r2.returncode}: {(r2.stderr or r2.stdout)[:60]}"}
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Incremental (--incremental)", "suite": profile_name,
+                                "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Chunk size (--chunk-size 5242880)
+            feature_flags = BASE_CLIENT_FLAGS + ["--chunk-size", "5242880"]
+            cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + feature_flags
+            print(f"\n  --- Chunk size (--chunk-size 5242880) ---\n    Running: {' '.join(cmd)}")
+            try:
+                r = run_single_test(cmd, "Chunk size (--chunk-size 5242880)", source_dir, dest_dir)
+                r["suite"] = profile_name
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Chunk size (--chunk-size 5242880)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # Delete (--delete) — pre-populate dest, add extra files, then sync with --delete
+            # Note: server handles one client per launch, so we restart between syncs
+            print(f"\n  --- Delete (--delete) ---")
+            try:
+                flags = BASE_CLIENT_FLAGS + ["-M"]
+                # First sync (no delete) to populate dest
+                s1 = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
+                time.sleep(0.5)
+                first_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags
+                r1 = subprocess.run(first_cmd, text=True, capture_output=True)
+                wait_proc(s1)
+                if r1.returncode != 0:
+                    raise RuntimeError(f"First sync failed: {r1.stderr[:100]}")
+                # Add extra files to received dir
+                received = os.path.join(dest_dir, os.path.abspath(source_dir).lstrip(os.sep))
+                extra_path = os.path.join(received, "extra_file.txt")
+                with open(extra_path, "w") as f:
+                    f.write("should be deleted")
+                extra_dir = os.path.join(received, "extra_dir")
+                os.makedirs(extra_dir, exist_ok=True)
+                with open(os.path.join(extra_dir, "nested.txt"), "w") as f:
+                    f.write("nested extra")
+                # Second sync with --delete (fresh server)
+                s2 = subprocess.Popen(SERVER_CMD, stdout=subprocess.DEVNULL, stderr=None)
+                time.sleep(0.5)
+                second_cmd = client_prefix + BASE_CLIENT_CMD + ["--source-dir", source_dir, "--dest-dir", dest_dir] + flags + ["--delete"]
+                start = time.monotonic()
+                r2 = subprocess.run(second_cmd, text=True, capture_output=True)
+                duration = time.monotonic() - start
+                wait_proc(s2)
+                r = {"name": "Delete (--delete)", "suite": profile_name}
+                if r2.returncode == 0 and not os.path.exists(extra_path) and not os.path.exists(extra_dir):
+                    mismatches, missing = verify_transfer(source_dir, received)
+                    if not mismatches and not missing:
+                        r["status"] = "Success"
+                        r["time"] = f"{duration:.4f}s"
+                        r["error"] = ""
+                    else:
+                        r["status"] = "Failed"
+                        r["time"] = "N/A"
+                        r["error"] = f"post-delete verify: mismatches={len(mismatches)}, missing={len(missing)}"
+                else:
+                    r["status"] = "Failed"
+                    r["time"] = "N/A"
+                    errs = []
+                    if r2.returncode != 0:
+                        errs.append(f"Exit {r2.returncode}: {(r2.stderr or r2.stdout)[:60]}")
+                    if os.path.exists(extra_path):
+                        errs.append("extra_file.txt remains")
+                    if os.path.exists(extra_dir):
+                        errs.append("extra_dir remains")
+                    r["error"] = " | ".join(errs)
+                results.append(r)
+            except Exception as e:
+                results.append({"name": "Delete (--delete)", "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
+
+            # SSH feature tests
+            if SSH_AVAILABLE:
+                ssh_dest = f"localhost:{dest_dir}_ssh"
+                ssh_feature_cases = [
+                    {"name": "SSH Archive (-a)", "flags": ["-a"]},
+                    {"name": "SSH Exclude (--exclude small.txt)", "flags": ["--exclude", "small.txt"], "expected_missing": ["small.txt"]},
+                ]
+                for case in ssh_feature_cases:
+                    flags = BASE_CLIENT_FLAGS + case["flags"]
+                    cmd = BASE_CLIENT_CMD + [source_dir, ssh_dest] + flags
+                    print(f"\n  --- {case['name']} ---\n    Running: {' '.join(cmd)}")
+                    try:
+                        r = run_single_test(cmd, case["name"], source_dir, f"{dest_dir}_ssh",
+                                            no_server=True,
+                                            expected_missing=case.get("expected_missing"))
+                        r["suite"] = profile_name
+                        results.append(r)
+                    except Exception as e:
+                        results.append({"name": case["name"], "suite": profile_name, "status": "Error", "time": "N/A", "error": str(e)})
 
     except (subprocess.CalledProcessError, RuntimeError) as e:
         print(f"  Error: {e}")
@@ -535,19 +594,26 @@ def check_ssh_localhost():
     build_dir = os.path.abspath("build")
     server_path = os.path.join(build_dir, "server")
 
-    r = subprocess.run(["ssh", "-o", "BatchMode=yes", "-o", "ConnectTimeout=5",
-                        "localhost", "which", "fastsync-server"],
-                       capture_output=True, timeout=10)
+    try:
+        r = subprocess.run(["ssh", "-o", "BatchMode=yes", "-o", "ConnectTimeout=5",
+                            "localhost", "which", "fastsync-server"],
+                           capture_output=True, timeout=10)
+    except FileNotFoundError:
+        SSH_AVAILABLE = False
+        return
     if r.returncode == 0:
         SSH_AVAILABLE = True
         return
 
     SSH_AVAILABLE = False
     # Try each PATH dir: create symlink, then verify with which
-    r = subprocess.run(
-        ["ssh", "-o", "BatchMode=yes", "localhost",
-         'echo "$PATH"'],
-        capture_output=True, timeout=10, text=True)
+    try:
+        r = subprocess.run(
+            ["ssh", "-o", "BatchMode=yes", "localhost",
+             'echo "$PATH"'],
+            capture_output=True, timeout=10, text=True)
+    except FileNotFoundError:
+        return
     if r.returncode != 0:
         return
     for d in r.stdout.strip().split(":"):
@@ -628,9 +694,10 @@ def main():
     parser.add_argument("--keep-data", action="store_true")
     parser.add_argument("--unlimited", action="store_true")
     parser.add_argument("--wan", action="store_true")
+    parser.add_argument("--full", action="store_true", help="Run full test suite with network shaping, SSH, rsync benchmarks")
     args = parser.parse_args()
 
-    total_bytes = generate_test_files(args.source_dir)
+    total_bytes = generate_test_files(args.source_dir, full=args.full)
     if os.path.exists(args.dest_dir):
         shutil.rmtree(args.dest_dir)
     os.makedirs(args.dest_dir, exist_ok=True)
@@ -641,12 +708,12 @@ def main():
     elif args.wan:
         profiles.append("WAN")
     else:
-        profiles.append("LAN")
+        profiles.append("LAN" if args.full else "Unlimited")
 
     try:
         all_results = []
         for p in profiles:
-            all_results.extend(run_profile(p, args.source_dir, args.dest_dir))
+            all_results.extend(run_profile(p, args.source_dir, args.dest_dir, full=args.full))
 
         print("\n" + "=" * 130)
         print(f"{'RESULTS':^130}")