Add missing IPV6_TRANSPARENT socket option to the TCP redirect listener
Control callback, matching what the UDP redirect listener already sets.
Without this, the kernel silently drops IPv6 TPROXY-redirected connections.
Also clean up handler_linux.go getOriginalDstAddr:
- Remove encoding/binary import and heap allocation for port conversion
- Replace with zero-allocation ntohs (native-to-network byte order swap)
- Document the struct layout hack where GetsockoptIPv6Mreq and
GetsockoptIPv6MTUInfo are used to read sockaddr_in/sockaddr_in6
from SO_ORIGINAL_DST (kernel returns smaller structs than the
getter functions expect, but only the first N bytes are populated)
Fixesgo-gost/gost#126
The readTimeout field (default 15s) was being applied via xnet.Pipe to both
directions of a bidirectional proxy connection. During asymmetric transfers
(e.g. HTTP file download), the direction reading from the tunnel sees no
data after the initial request is forwarded, causing SetReadDeadline to fire
after 15s and abort the entire transfer.
Fix: add a separate idleTimeout field (default 0=disabled) to the metadata
structs in both forward/local and forward/remote handlers, and switch
xnet.Pipe to use idleTimeout instead of readTimeout. The readTimeout field
now only applies to the initial protocol sniffing/handshake phase.
Also document readTimeout vs idleTimeout semantics across all 24 locations
in the x/ module where these timeouts appear:
- readTimeout: handshake sniffing deadline (handlers), upstream response
header timeout (http.Transport), or transport-level read deadline
- idleTimeout: idle read deadline per Pipe direction (0=disabled)
- ReadTimeout on Sniffer/SnifferBuilder: upstream response header/TLS
handshake read timeout during sniffing