opt: disable SO_REUSEPORT on Unix domain sockets

gnet.go

@@ -464,6 +464,16 @@ func createListeners(addrs []string, opts ...Option) ([]*listener, *Options, err
  options.WriteBufferCap = math.CeilToPowerOfTwo(wbc)
  }
 
+ var hasUDP, hasUnix bool
+ for _, addr := range addrs {
+ proto, _, err := parseProtoAddr(addr)
+ if err != nil {
+ return nil, nil, err
+ }
+ hasUDP = hasUDP || strings.HasPrefix(proto, "udp")
+ hasUnix = hasUnix || proto == "unix"
+ }
+
  // SO_REUSEPORT enables duplicate address and port bindings across various
  // Unix-like OSs, whereas there is platform-specific inconsistency:
  // Linux implemented SO_REUSEPORT with load balancing for incoming connections
@@ -478,22 +488,19 @@ func createListeners(addrs []string, opts ...Option) ([]*listener, *Options, err
  // with the capability of load balancing, it's the equivalent of Linux's SO_REUSEPORT.
  // Also note that DragonFlyBSD 3.6.0 extended SO_REUSEPORT to distribute workload to
  // available sockets, which make it the same as Linux's SO_REUSEPORT.
+ // AF_LOCAL with SO_REUSEPORT enables duplicate address and port bindings without
+ // load balancing on Linux and *BSD. Therefore, disable it for Unix domain sockets.
  goos := runtime.GOOS
  if (options.Multicore || options.NumEventLoop > 1) && options.ReusePort &&
- goos != "linux" && goos != "dragonfly" && goos != "freebsd" {
+ ((goos != "linux" && goos != "dragonfly" && goos != "freebsd") || hasUnix) {
  options.ReusePort = false
  }
 
- // If there is UDP listener in the list, enable SO_REUSEPORT and disable edge-triggered I/O by default.
- for i := 0; (!options.ReusePort || options.EdgeTriggeredIO) && i < len(addrs); i++ {
- proto, _, err := parseProtoAddr(addrs[i])
- if err != nil {
- return nil, nil, err
- }
- if strings.HasPrefix(proto, "udp") {
- options.ReusePort = true
- options.EdgeTriggeredIO = false
- }
+ // If there is UDP address in the list, we have no choice but to enable SO_REUSEPORT anyway,
+ // also disable edge-triggered I/O for UDP by default.
+ if hasUDP {
+ options.ReusePort = true
+ options.EdgeTriggeredIO = false
  }
 
  listeners := make([]*listener, len(addrs))

options.go

@@ -125,7 +125,7 @@ type Options struct {
 
  // EdgeTriggeredIO enables the edge-triggered I/O for the underlying epoll/kqueue event-loop.
  // Don't enable it unless you are 100% sure what you are doing.
- // Note that this option is only available for TCP protocol.
+ // Note that this option is only available for stream-oriented protocol.
  EdgeTriggeredIO bool
 }