stats.WrapUDPConn returned nil when pStats was nil (introduced in 7c95d40),
but callers in the kcp and rudp listeners passed the result directly to
admission.WrapUDPConn and limiter.WrapUDPConn, which wrapped a nil PacketConn.
When service.Serve() called conn.LocalAddr(), the auto-generated method
delegated to the nil PacketConn, causing a panic.
Root cause: WrapUDPConn behavior was inconsistent with WrapConn and
WrapPacketConn in the same package, which both return the original connection
instead of nil when the optional config is absent.
Fixes:
1. listener/kcp, listener/rudp — guard stats.WrapUDPConn with Stats != nil
(consistent with quic and wt listeners which already had this guard).
2. observer/stats/wrapper — when pStats is nil, pass through the original
connection instead of returning nil (matches WrapConn/WrapPacketConn).
3. admission/wrapper, limiter/traffic/wrapper — add defensive nil guards:
nil pc → return nil; nil config → pass through original connection.
All four WrapUDPConn implementations now share the same nil semantics.
4. listener/udp_wrapper_safety_test.go — regression test that verifies the
full metrics→stats→admission→limiter chain with all optional configs nil
does not produce a wrapper with a nil internal PacketConn.
Fixes: go-gost/gost#873
Mirror WrapConn behavior: WrapUDPConn now increments total and current
connection counts on creation (one accepted UDP client session == one
connection) and decrements the current count on Close. Close is guarded
by a mutex and a closed channel so it is safe to call multiple times —
the current-conns decrement fires exactly once and the monotonic total
is untouched.
Add UnwrapConn() to the admission, proxyproto, conn limiter, metrics,
and observer/stats TCP connection wrappers, complementing the traffic
limiter's limitConn added in the previous commit.
This makes the unwrapConn() helper in handler/sshd able to peel through
any combination of these wrappers uniformly, keeping the pattern
complete and future-proof for handlers that assert on concrete
connection types.
The WrapUDPConn constructor returns nil when either arg is nil, so
c.stats is always non-nil in all udpConn methods. Remove 8 redundant
nil guards that were inconsistent with packetConn (which already
skipped them).
Add 65 unit tests across plugin, stats, and wrapper packages covering
nil safety, race conditions, double-close, event marshaling, and
reset-traffic semantics. Replace magic numbers in tests with named
Kind constants.
- WrapUDPConn, WrapPacketConn, WrapListener: add nil guards for pc/ln params
- NewGRPCPlugin: return no-op observer instead of nil on connection error
- gRPC plugin: fix resource leak by wiring Close() through observerWrapper
and service.Close() lifecycle
- Both plugins: log unknown event types instead of silently dropping them
- httpPlugin: remove dead nil check for always-non-nil client field
- Stats.Reset: update core interface doc to match implementation behavior
- Add doc comments to all exported symbols across the observer package
ginuerzh