When the user specifies an IP address as the interface (e.g.
interface=10.1.1.1), GOST resolved it to its hosting interface and
called SO_BINDTODEVICE on it — breaking outbound connectivity for
IP aliases on loopback or dummy interfaces (go-gost/gost#785).
The initial fix (caa82f2) only skipped SO_BINDTODEVICE for loopback
interfaces, missing non-loopback dummy interfaces like ip-aliases.
This change adds an isIP return value to ParseInterfaceAddr so callers
can distinguish 'user specified an IP' (intent: source IP binding for
policy routing — skip SO_BINDTODEVICE) from 'user specified an
interface name' (intent: force traffic through that NIC — keep
SO_BINDTODEVICE). The dialOnce method now only calls bindDevice when
bindToDevice is true AND the input was an interface name (!isIP).
The loopback-specific guard in bindDevice is reverted — superseded by
the broader isIP-based fix that covers all interface types.
Fix setMark early-return conditions that were inverted relative to
Linux: on FreeBSD (SO_USER_COOKIE) and OpenBSD (SO_RTABLE), a
non-zero mark was short-circuited instead of applied, disabling
socket marking entirely.
Also fix GetClientIP to trim leading whitespace from X-Forwarded-For
entries (per RFC 7239), and fix Body.Read to subtract len(b) instead
of n from recordSize when a single read exceeds the remaining quota.
Add unit tests for internal/net/ (addr, dialer, http, ip, net, pipe,
transport, resolve, proxyproto, udp).
ginuerzh