hole-punch: add Python impl (v0.5)

[parth-soni07]

PR: Python hole-punch implementation

Summary

Adds a Python (py-libp2p v0.5) implementation for the hole-punch test harness and fixes interoperability so that py×py and py×rust (Python dialer, Rust listener) tests pass with both Rust and Python relays. Scope is limited to Python-related tests; Rust-only failures are out of scope.

Test results (full 32-test matrix)

	Count
Passed	9
Failed	23

Passing (9)

• Python-related (8):
  • py×py (4): tcp/ws × [Rust relay, Python relay] — all pass
  • py×rust (4): tcp/ws × [Rust relay, Python relay] — all pass
• Rust-only (1): rust×rust (tcp, tls, mplex) [Rust relay]

Failing (23)

• Step 2 – in scope (4): rust×py (Rust dialer, Python listener) — tcp/ws × both relays
• Rust-only – out of scope (19): rust×rust (9), rust×py quic/webrtc (2), and other Rust-only combinations

Changes

New: Python implementation (hole-punch/images/python/v0.5/)

• peer.py – Python peer (listener/dialer) with:
  • Rust relay support: varint-framed HOP/STOP, protocol IDs 0.2.0/hop and 0.2.0/stop, _dial_rust_relay, _handle_rust_stop_stream
  • WebSocket transport fix: listen_addrs=[listen_addr] in new_host() so WS is used for /ws addresses
  • Circuit address in peerstore only when using Rust relay (avoids deadlock with Python relay)
• relay.py – Python relay with Rust compatibility:
  • Varint encode/decode, handlers for 0.2.0/hop and 0.2.0/stop
  • Custom HOP handler that processes RESERVE then CONNECT on the same stream and routes Python dialer → Rust listener via _open_rust_stop / _handle_py_connect_to_rust
• Dockerfiles, run scripts, requirements for peer and relay images

Rust

• relay.rs – swarm.add_external_address(address) after listen so RESERVE OK includes the address (avoids NoAddressesInReservation for clients).
• peer.rs – Listener only:
  • Break when my_observed_addr.is_some() (do not require Identify::Sent) so listener proceeds with Python relay
  • Publish listener_peer_id to Redis after 2s delay (Python relay wire format does not emit ReservationReqAccepted the same way)

Harness / config

• images.yaml – Register Python implementation and relay.
• generate-tests.sh / run-single-test.sh – Wiring for Python images and test matrix.

[parth-soni07]

ccing @acul71 @seetadev @sumanjeet0012

currently working on the rust×py (Rust dialer, Python listener) — tcp/ws × both relays to fix the failing tests there

[dhuseby]

@parth-soni07 I just fixed the rust-v0.56 hole punch tests in #48

One of the bugs I discovered was a problem in the iptables configuration in the linux NAT/routers. So your tests won't work until #48 lands and you merge it into this branch.

[dhuseby]

BTW, websockets and webrtc-direct connections cannot hole-punch due to protocol incompatibilities. When you run your tests use --transport-ignore 'ws|webrtc-direct'

[parth-soni07]

@parth-soni07 I just fixed the rust-v0.56 hole punch tests in #48

One of the bugs I discovered was a problem in the iptables configuration in the linux NAT/routers. So your tests won't work until #48 lands and you merge it into this branch.

ohh, yes i think this explains why even if the DCUtR handshake completes correctly between the Python listener and Rust dialer, the actual hole-punch would fail. Meanwhile till #48 lands, I'll have a look at the changes you made in it for my sake of understanding.

[parth-soni07]

BTW, websockets and webrtc-direct connections cannot hole-punch due to protocol incompatibilities. When you run your tests use --transport-ignore 'ws|webrtc-direct'

Sure sure, thanks @dhuseby!!

[dhuseby]

@parth-soni07 it looks like you need to merge master into your branch and push again.

[parth-soni07]

@parth-soni07 it looks like you need to merge master into your branch and push again.

ohh, yesyes, DONE!!, thanks @dhuseby!