Fix SO_REUSEPORT for macOS #626

pkg/mdns/syscall_darwin.go

@@ -0,0 +1,24 @@
+package mdns
+
+import (
+	"syscall"
+)
+
+func SetsockoptInt(fd uintptr, level, opt int, value int) (err error) {
+	// change SO_REUSEADDR and REUSEPORT flags simultaneously for BSD-like OS
+	// https://github.com/AlexxIT/go2rtc/issues/626
+	// https://stackoverflow.com/questions/14388706/how-do-so-reuseaddr-and-so-reuseport-differ/14388707
+	if opt == syscall.SO_REUSEADDR {
+		if err = syscall.SetsockoptInt(int(fd), level, opt, value); err != nil {
+			return
+		}
+
+		opt = syscall.SO_REUSEPORT
+	}
+
+	return syscall.SetsockoptInt(int(fd), level, opt, value)
+}
+
+func SetsockoptIPMreq(fd uintptr, level, opt int, mreq *syscall.IPMreq) (err error) {
+	return syscall.SetsockoptIPMreq(int(fd), level, opt, mreq)
+}

pkg/mdns/syscall.go → pkg/mdns/syscall_linux.go

@@ -1,8 +1,8 @@
-//go:build darwin || linux
-
 package mdns
 
-import "syscall"
+import (
+	"syscall"
+)
 
 func SetsockoptInt(fd uintptr, level, opt int, value int) (err error) {
 	return syscall.SetsockoptInt(int(fd), level, opt, value)