## Why
Native TCP clients need to reach managed network destinations without implementing proxy support themselves.
## What changed
- Add `--transparent-tcp` to the Linux sandbox command, using a bundled TCP stack, private TUN interface, and DNS stub to route native IPv4 and IPv6 connections through the attributed managed SOCKS proxy.
- Preserve original hostnames for proxy policy checks and cancel pending approval connections when their native sockets close.
- Expose `--linux-sandbox-transparent-tcp` and `--tcp-upstream-proxy` on `codex exec-server` for transparent routing and a mandatory HTTP CONNECT next hop without direct fallback.
- Require private network and PID namespaces, private procfs, system `bwrap`, and access to `/dev/net/tun`; reject incompatible launcher options and untrusted proxy ports.
## Testing
Add integration coverage for native hostname and IPv6 connections, SOCKS attribution, pending connection cancellation, policy denials, and filesystem and host-loopback isolation. Extend launcher and executor tests for option validation and managed-policy propagation.
GitOrigin-RevId: 96bd7726e5369efceb65320face56aa85ae3deb8
viyatb-oai
7194b21776