The embedded interface's TCP forwarder admits 65535 connections in
flight for all peers together, and a forwarded request holds its slot
until the handshake ends or gVisor gives up on it. One client sending
bare SYNs from fresh source ports therefore took every slot and left
the other clients' connections unanswered. The UDP relay likewise
opened a SOCKS5 association and a host UDP socket for every fresh
tunnel source port with no per-peer bound.
The forwarder now names the peer on the SYN, refuses a source no peer
owns and caps one peer at 4096 connections; the UDP relay caps one peer
at 1024 sessions and drops the datagrams that would need more.
The TCP forwarder handler read the tunnel client's address from the
accepted connection's RemoteAddr, which asks the live endpoint and is
nil once the peer's RST has been processed. A client sending SYN, ACK
and RST through its own tunnel could hit that window and crash the panel
on a goroutine with no recover. The forwarder now hands the handler the
source from the request's endpoint ID, as it already did for the
destination.
MHSanaei