A connection's two 16 KiB relay buffers lived inline in its slot, so every
connection that had moved a byte kept those pages resident even while idle.
They now come from one ObjectPool with two buffers per connection slot: a
connection leases a buffer while bytes wait in it and returns it when it
drains, and the LIFO free list hands the same warm pages to the next busy
connection. The pool covers every direction of every slot, so a lease never
fails and reads never wait on it.
With 1,000 idle connections, ss-server drops from 35.4 to 27.2 KiB per
connection on Linux (C: 26.2) and from 73.9 to 42.2 KiB on macOS. The slot
shrinks from 104 to 68 KiB.
FixedBuffer gains a user-provided constructor so that value-initialising one
(a pool lease, a variant alternative) no longer zero-fills its storage.
* Rename test_jconf.c to test_jconf_cpp.cpp
* Parse the config file on arenas
read_jconf now reads the file and builds the JSON tree in a scratch arena
that is released before it returns, and copies the parsed strings into one
process-lifetime arena instead of a malloc per string. parse_addr and the
config parser share one address splitter.
Port test_jconf to C++ and cover every field copied out of the parse tree,
a re-read, and the densest file the size limit accepts.
* tests: rename remaining C unit tests to .cpp (no content changes)
* tests: port remaining C unit tests to the C++ test harness
Convert acl, acl_literal, aead2022, base64, buffer, cache (legacy
reference), crypto, ipset, ipset_reference, json, netutils, ppbloom,
process, ref, ssurl and utils tests to test_helpers.hpp. ctest names are
unchanged; every assertion is kept. Build the ported sources with the
strict C++ warning set.
* Run clang-tidy on every ported test
The test regex skipped file names with digits (test_aead2022_cpp.cpp,
test_base64_cpp.cpp); include them, fix the two optional accesses it then
reports, and build test_jconf with the strict warning set.
* docs: per-connection RSS on Linux against the C relay
* test_jconf: check read_jconf results before using them
* Remove the stream ciphers
The unauthenticated stream ciphers (aes-*-cfb, aes-*-ctr, camellia-*-cfb,
chacha20, chacha20-ietf, salsa20) are gone from every build, together
with the SS_ENABLE_LEGACY option, the C++ stream codecs, their C test
oracle and the stream-only tests and configurations. A configuration
naming one of them, or RC4/table, now fails at startup with a message
pointing to an AEAD method, and test_cli checks that.
Shell completions list only the supported methods (and now include the
2022 ones), and the docs and the compatibility contract say the stream
ciphers were removed.
* Drop the Mbed TLS CFB requirement and stale stream-cipher examples
CFB was only needed by the removed stream ciphers, so a system Mbed TLS
built without it no longer fails to configure. The public header example
now uses aes-256-gcm.
* Remove ss_event and the C resolver shim
Each program's loop, signals, plugin watcher and stats timer now go
through ss::event::Program (src/event/program.hpp), held on main()'s
stack; ss-manager uses it too. ss-server resolves the manager address
with the relay resolver. With no C caller left, ss_event.cpp/.h,
resolv.cpp/.h and their C tests go; test_resolver_cpp.cpp replaces the
resolver tests against the same delayed local DNS server, and ss_ev is
now an interface target over libuv.
* Reinitialize the event loop after daemonize()
The loop is created before the programs fork into the background, and
kqueue/epoll descriptors do not survive fork(), so ss-server -f (which
ss-manager always uses) died as soon as it ran. Call uv_loop_fork() in
the child.
* Move the C codecs to tests/reference and drop uthash from ss-manager
The programs now use only the C++ codecs. The C stream/AEAD/AEAD-2022
implementations stay as the reference the differential tests and the C
unit tests compare against. Key derivation and the cipher tables used by
the doc snippets move to src/crypto/keys.{hpp,cpp}.
ss-manager keeps its servers in an ss_list (at most MAX_PORT_NUM,
looked up only on control messages) instead of a uthash table, and
tests/test_manager.py covers add/ping/list/remove end to end.
* Replace uthash and ss_list with the C++ containers
The C cache (now used only by the reference codecs) moves to
tests/reference and src/uthash.h is deleted. ACL rules and ss-manager's
servers are ListNodes on IntrusiveLists; destroying an element unlinks
it, so the free paths no longer have to remember to. core.h keeps only
ss_ip. test_rule is ported to C++ and also covers literal rules.
* Describe the C++20/libuv build in the Debian and snap metadata
* Keep clang-tidy clean in the new C++ tests
* Add --max-dns-queries / max_dns_queries
Sizes the resolver's query pool, the last of the capacity settings the
no-heap-after-startup design calls for. Defaults are unchanged: the
connection limit (plus 64 on ss-server, which also resolves for its
statistics).
* Report the C++20 rewrite: allocation, size, throughput and memory
docs/performance.md compares master (C) with the C++ engine on macOS
arm64: zero heap allocations per connection or datagram (from 27-89),
TCP throughput within noise, and about 20 MiB more RSS at 1,000 open
connections from the inline per-connection buffers. docs/cpp-core.md
and CLAUDE.md now describe the finished layout.
* Fix the MinGW build of ss-server: stat_resolver is POSIX-only
* Fix the fully static image and the build image for the C++ sources
docker/static: the C++ unit tests link the static libstdc++, whose error
paths need an unwinder that --rtlib=compiler-rt does not provide; link
llvm-libunwind. The programs themselves still need no C++ runtime.
docker/build: build in the default bundled mode with CMake instead of
against libev/udns (Alpine's Mbed TLS 4 is not supported by system
mode).
* Fall back to the system heap when a library realloc cannot be served
heap_realloc returned NULL when a block outgrew the largest size class or
the budget, and libuv aborts when growing its watcher array fails: a poll
on fd 8190 or above (about 4,000 connections) killed the process.
Move the block to the system heap instead, as malloc and calloc already
do. test_heap_guard_cpp polls fd 16380 with the heaps installed.
* Leave pool room for UDP sessions that are still closing
An evicted session keeps its pool slot until its socket's close callback
runs, so with pool capacity equal to the table's the acquire after an
eviction failed: a full table dropped new-session packets after evicting
a live session for nothing. The AEAD-2022 shared-session pool had the
same problem with entries still referenced by relay sessions.
* Time client-side TCP connections when idle, not only while connecting
ss-local, ss-tunnel and ss-redir only timed the upstream connect (as the
C relays did), so a client that never finished its SOCKS handshake, or a
stream whose peer vanished without a FIN, held a pool slot forever. With
the pool now a hard cap that pauses accepting when full, enough of them
stopped the listener for good. Every connection now starts with the idle
deadline, connected() re-arms it, and traffic refreshes it for all kinds
(the idle timeout keeps its 24 h floor, MIN_TCP_IDLE_TIMEOUT).
* Include <algorithm> for std::min in crypto/keys.cpp (CLANG64)
* test.py: accept host:port for --dns
The tunnel test hard-coded port 53, so it could only use a public
resolver or root. With a port it runs against a local DNS stand-in.
* Use the Mbed TLS compat wrappers for MD5 key derivation
* Fix the documentation build after moving the codecs
utils.cpp's \snippet aead.cpp and stream.cpp now live in src/crypto/,
which was not on Doxygen's EXAMPLE_PATH, so the man1 and HTML builds
failed. List the documentation sources explicitly instead of guessing
their extension.
* Add allocation-free C++ stream cipher codecs
src/crypto/stream.hpp implements the legacy stream methods this build
supports (AES CFB/CTR, Camellia CFB, Salsa20, ChaCha20, ChaCha20-IETF)
as value types. The AES and Camellia contexts are held by value through
Mbed TLS's block-cipher APIs instead of an allocated
mbedtls_cipher_context_t, and the libsodium ciphers track their
keystream position, finishing partial 64-byte blocks from a stack block
instead of the padding copies stream.cpp makes.
test_crypto_stream_cpp runs TCP streams (with fragments that split
keystream blocks) and UDP packets between the C and C++
implementations in both directions for all twelve methods and checks
IV replay; alloc_steady_crypto_stream requires zero allocations for new
connections and packets.
* Document the crypto codecs, cache rewrite and allocation progress
* Include <algorithm> for std::min in test_crypto_stream_cpp.cpp
* Do not memcpy from an empty span in the stream decoder
An empty read before the IV arrived passed a null source to memcpy,
which UBSan reports (and the ASan CI job turns into a failure).
* Include C++ headers before crypto.h in test_crypto_stream_cpp.cpp
crypto.h defines min/max macros for the C sources; libstdc++ headers
included after it fail to parse.
src/event/loop.hpp wraps uv_loop/poll/timer/signal/async handles that
live by value inside their owner and dispatch to an owner member
function chosen at compile time. A Poll owns its socket and carries
read and write interest on one handle, closing the descriptor in
libuv's close callback. CloseGroup collects the asynchronous closes of
an owner's handles and reports completion afterwards, which is how
pooled owners implement AsyncClosable. DeadlineList drives the idle
timeouts of many owners from one timer.
test_event_cpp covers readiness, closing a peer from inside a
callback, recycling a pooled owner only after its handles closed,
repeating timers, deadline ordering and cross-thread wakeups.
* Make headers and leaf modules compile as C++
Wrap the declarations of every project header in extern "C" (after the
system includes, which must keep C++ linkage), so converted modules and
the remaining C files agree on linkage.
In the leaf modules, cast allocator and memchr results explicitly,
rename identifiers called new, replace the getpwnam_r VLA with the
fixed 16 KiB buffer the loop already capped itself at, and make the
rlimit initialiser conversion explicit. All of this is still valid C.
* Compile the leaf modules as C++
Rename base64, json, ipset, process, ppbloom, rule, ssurl and cache from
.c to .cpp without touching their contents, and update the CMake source
lists, debian/copyright and the docs.
Ported code keeps -Wall; -Wextra is now opt-in through
ss_strict_warnings() for code written as C++ (the core tests).
check_no_heap.py gains a ratchet baseline for the converted modules,
which still allocate the way the C code did. A new check_cxx_runtime
test verifies with nm that the programs and libshadowsocks-c.a still
need no C++ runtime library, so C consumers are unaffected.
* Fix the Windows branches of process.cpp for C++
Cast allocator results and the thread argument explicitly and
value-initialise JOBOBJECT_EXTENDED_LIMIT_INFORMATION with {}. Found by
the zig x86_64-windows-gnu cross build.
* Keep clang-tidy clean for the converted modules
Once the C headers are included from C++ translation units,
bugprone-dynamic-static-initializers reports each extern variable
declaration in them; none is defined in a header, so disable the check.
Mark the two bounded memchr searches in ssurl.cpp, which
bugprone-not-null-terminated-result misreads as string copies.
* check_cxx_runtime: ignore glibc symbol versions
nm on glibc prints __cxa_atexit@GLIBC_2.2.5, which the allowlist for the
libc-provided __cxa_atexit/__cxa_finalize did not match.
* Keep GCC's C++-only warnings off for modules converted from C
GCC's C++ -Wall includes -Wsign-compare and -Wclass-memaccess, which C's
-Wall does not, so the converted modules failed -Werror on GCC (Linux,
UCRT64) although nothing in them changed. They keep the warning set they
were written against; code under ss_strict_warnings() re-enables both.
* Enable C++20 alongside C11 in the build
Add CXX to the project with C++20 (no extensions) and build C++ sources
with -Wextra -fno-exceptions -fno-rtti -fno-threadsafe-statics on top of
the existing warning flags. Give every toolchain a C++ compiler: the zig
Windows toolchain, the static macOS/Windows CI jobs, the static musl
image (clang++ plus libstdc++ headers) and the RPM spec.
* Add C++20 ownership and allocation core
Header-only primitives for the no-heap-after-startup design:
Result/Status, Region, ObjectPool with PoolPtr (std::unique_ptr with a
pool deleter), generation-checked Handle and asynchronous close support,
intrusive RefPtr, FixedBuffer, MonotonicArena, FixedHashMap and FixedLru,
IntrusiveList, and a bounded FixedHeap for third-party allocator hooks.
Unit tests cover each primitive (test_core_*). scripts/check_no_heap.py
rejects heap allocation in C++ sources under src/ and runs as a ctest.
clang-tidy now also analyses C++ sources and the core headers.
* Add heap allocation audit for relayed connections
alloc_counter is a preloadable malloc counter (glibc, macOS) that writes
a snapshot on SIGUSR2. measure_alloc.py warms ss-local and ss-server up,
snapshots both, relays more connections and reports allocations per
connection. It runs report-only as the alloc_audit_report ctest.
interop.peers() now yields the started processes.
* Document the C++20 port and allocation baseline
docs/cpp-core.md describes the language profile, the core primitives,
the phase plan and the measured C baseline (77-89 allocations per
connection in ss-server, 27-39 in ss-local). The compatibility contract
now keeps the C11 public header instead of a C11 code base. CLAUDE.md
drops stale libev, submodule and gnu99 references.
* Fix CI for the C++ core: libstdc++ headers, static unwinder, newer clang
- docker/static: Alpine's libstdc++ headers come with g++, and the C++
tests' static libstdc++ needs an unwinder that compiler-rt lacks; add
g++ and llvm-libunwind.
- FixedBuffer: drop the unused kCapacity (clang-tidy 18 reports it as a
dynamically initialized header static).
- ss-server on Windows: manager_addr was only read in POSIX-only code,
which newer clang rejects (-Wunused-but-set-global); say that the
option is ignored there.
* CI: allow running the test and build workflows by hand
Stacked PRs target their parent branch, which these workflows do not
trigger on; workflow_dispatch lets each layer run the full matrix.
* CI: let clang-tidy ignore GCC-only warning flags
The compile database comes from a GCC build, whose flags (for example
-Wno-class-memaccess) clang-tidy does not know and reports as errors.
Add `ss-local --printable-salt` / `"printable_salt": true`, disabled by
default. For each outgoing TCP salt it picks a prefix length uniformly
from 6-12 bytes and samples those bytes as printable ASCII (0x20-0x7e)
immediately before key derivation. The salt stays 32 bytes with no
framing or markers, so the wire format is unchanged and any stock
server interoperates. Only chacha20-ietf-poly1305 and aes-256-gcm are
accepted; other ciphers fail at startup. UDP, server responses, and
AEAD-2022 are untouched.
Crypto unit tests cover length distribution, empty first writes, exact
framing overhead, salt-tail preservation, byte-at-a-time decryption,
tampering and replay rejection. CLI tests check local-only exposure and
cipher rejection via flag, config key and bad config type. interop.py
gains --printable-salt and --server-bin for independent stock servers.
docs/printable-salt.md records the design, entropy bound, fingerprint
caveats and route-experiment procedure; docs/encoding-experiments.md
and tests/experiments/ hold the Base85/lowpop85/TLS outer-transport
prototypes. docs/measurements/printable-salt-2026-09-23/ archives the
sanitized results of the aborted field trials.
Co-authored-by: Claude <noreply@anthropic.com>
Rename the project to shadowsocks-c while retaining ss-* commands, the embedding ABI, and legacy library/package lookup compatibility.
Replace libev with bundled libuv for IOCP/kqueue event backends, expand asynchronous runtime DNS coverage, and add actionlint/Ruff with strict clang-tidy failure handling. Validate native platforms, static builds, packaging, interoperability, sanitizers, and canonical/legacy consumers.
All 22 hosted checks pass at reviewed head a8493250eb.
Bundle pinned offline dependencies, remove libcork/libipset and submodule requirements, and add portable runtime helpers with relocatable static/shared library installations.
Add Clang static build validation for Linux/musl, macOS and Windows, real TCP/UDP and SIP003 interoperability coverage, and recorded performance tradeoffs. All 21 hosted checks pass at the reviewed PR head 8d504e6218.
Max Lv
