Files
s5p/PROJECT.md
user fc1dea70f4 docs: update project docs for warm start and chain health check
Add warm start and chain pre-flight sections to USAGE. Mark both
features complete in ROADMAP and TASKS. Remove implemented items
from TODO. Update README, PROJECT, and CHEATSHEET.
2026-02-15 16:00:23 +01:00

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s5p -- Project

Purpose

A lightweight SOCKS5 proxy server that chains connections through Tor and/or arbitrary proxy hops (SOCKS4, SOCKS5, HTTP CONNECT).

Motivation

Existing solutions (proxychains-ng) rely on LD_PRELOAD hacks, only work on Linux, and intercept at the library level. s5p is a proper SOCKS5 server that any application can use natively -- no injection required.

Architecture

                  TCP          tunnel        tunnel
Client -------> s5p -------> Hop 1 -------> Hop 2 -------> Target
        SOCKS5       proto1         proto2         protoN
  • server.py -- asyncio SOCKS5 server, bidirectional relay, signal handling
  • proto.py -- protocol handshakes (SOCKS5, SOCKS4/4a, HTTP CONNECT), chain builder
  • config.py -- YAML config loading, proxy URL parsing, pool config
  • pool.py -- managed proxy pool (multi-source, health-tested, persistent)
  • source.py -- legacy proxy source (single HTTP API, kept for backward compat)
  • cli.py -- argparse CLI, logging setup, cProfile support

Deployment

Method Command
Local venv pip install -e . then s5p -c config/s5p.yaml
Container make build && make up (Alpine, ~59MB)

Container mounts ./src and ./config/s5p.yaml read-only at runtime. No application code is baked into the image.

Dependencies

Package Purpose
pyyaml Config file parsing

All other functionality uses Python stdlib (asyncio, socket, struct).

Design Decisions

  • No LD_PRELOAD -- clean SOCKS5 server, works with any client
  • asyncio -- single-threaded event loop, efficient for I/O-bound proxying
  • Domain passthrough -- never resolve DNS locally to prevent leaks
  • Tor as a hop -- no special Tor handling; it's just socks5://127.0.0.1:9050
  • Graceful shutdown -- SIGTERM/SIGINT handled in the event loop for clean container stops
  • Config split -- tracked example template, gitignored live config with real addresses
  • Proxy pool -- multi-source (API + file), health-tested, persistent, auto-cleaned
  • Weighted selection -- recently-tested proxies preferred via recency decay weight
  • Failure backoff -- connection failures penalize proxy weight for 60s, avoids retry waste
  • Stale expiry -- proxies dropped from sources evicted after 3 refresh cycles if not alive
  • Chain pre-flight -- static chain tested before pool health tests; skip on failure
  • Warm start -- quick-test alive subset on restart, defer full test to background