feat: OPENSHELL_DIRECT_TCP_ENDPOINTS for per-endpoint TCP bypass#1
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kosaku-sim merged 1 commit intofix/sandbox-dns-udp-acceptfrom Apr 21, 2026
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Adds a new env var parallel to OPENSHELL_DIRECT_TCP_HOSTS that accepts host:port pairs (comma-separated). Each pair installs iptables rules: - sandbox netns OUTPUT: ACCEPT to dest IP / dport - host POSTROUTING: MASQUERADE for the same dest/port - host FORWARD: ACCEPT for the same dest/port - child_env NO_PROXY: host portion added so HTTP clients also bypass Unlike DIRECT_TCP_HOSTS (broad TCP 443 ACCEPT), this is per-endpoint — required for: - non-HTTPS protocols the egress proxy cannot CONNECT-tunnel (postgres 5432, redis 6379 wire protocols) - ports the proxy explicitly blocks with ECONNRESET (5432, 6379, 15432, 16379 observed) - raw-TCP clients that ignore HTTP_PROXY env Host component may be an IPv4 literal or hostname; hostnames are resolved at pod startup via the pod netns resolver. IPv6 addresses are dropped (sandbox iptables rules are IPv4-only). Use case: sandbox reaching services on the pod host (postgres, redis, mailhog) via AUTODEV_HOST_IP without a port-forward daemon inside the sandbox. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Adds a new env var
OPENSHELL_DIRECT_TCP_ENDPOINTS(parallel toOPENSHELL_DIRECT_TCP_HOSTS) that accepts comma-separatedhost:portpairs, each installing per-endpoint iptables ACCEPT + MASQUERADE + FORWARD rules to bypass the egress proxy.Motivation
The existing
OPENSHELL_DIRECT_TCP_HOSTSinstalls a broad TCP 443 ACCEPT. This is sufficient for HTTPS services bypassing the proxy CA, but does not cover:access: fullHTTP_PROXYenv (e.g.pg,ioredis, smtp clients)Use case: sandbox reaching postgres/redis/mailhog on the pod host (via
AUTODEV_HOST_IP) without a port-forward daemon inside the sandbox.Changes
netns.rs:parse_direct_tcp_endpoints()— parsehost:portpairs with validationresolve_endpoint_ipv4s()— IPv4 literal or hostname resolution (IPv6 dropped)child_env.rs:build_no_proxy()also includes host portion of each endpoint (so rustls/curl bypass proxy for those hosts too)Verification
Built on Graviton (aarch64), binary deployed to the cluster container at
/opt/openshell/bin/openshell-sandbox, sandbox CRD env set to:Pod recreated. Probe from inside the sandbox:
10.0.1.215:5432(postgres)SELECT version()OK10.0.1.215:6379(redis)10.0.1.215:1025(smtp)10.0.1.215:8025(mailhog UI)Test plan
cargo test -p openshell-sandbox(unit tests for parsing + NO_PROXY)