feat: add ListenerControl callback to Config

config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/url"
 	"strconv"
+	"syscall"
 	"time"
 )
 
@@ -170,6 +171,11 @@ type Config struct {
 	// An implementation of the Logger interface
 	Logger Logger
 
+	// ListenerControl is called on the raw socket file descriptor after
+	// gosrt's built-in options (SO_REUSEADDR, IP_TOS, IP_TTL) are set
+	// but before the socket is bound. Same signature as net.ListenConfig.Control.
+	ListenerControl func(network, address string, c syscall.RawConn) error
+
 	// if a new IP starts sending data on an existing socket id, allow it
 	AllowPeerIpChange bool
 }

listen.go

@@ -9,6 +9,7 @@ import (
 	"net/netip"
 	"os"
 	"sync"
+	"syscall"
 	"time"
 
 	srtnet "github.com/datarhei/gosrt/net"
@@ -175,7 +176,15 @@ func Listen(network, address string, config Config) (Listener, error) {
 	}
 
 	lc := net.ListenConfig{
-		Control: ListenControl(config),
+		Control: func(network, address string, c syscall.RawConn) error {
+			if err := ListenControl(config)(network, address, c); err != nil {
+				return err
+			}
+			if config.ListenerControl != nil {
+				return config.ListenerControl(network, address, c)
+			}
+			return nil
+		},
 	}
 
 	network = "udp"

listen_test.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"strconv"
 	"sync"
+	"syscall"
 	"testing"
 	"time"
 
@@ -27,6 +28,22 @@ func TestListenReuse(t *testing.T) {
 	ln.Close()
 }
 
+func TestListenerControl(t *testing.T) {
+	called := false
+
+	config := DefaultConfig()
+	config.ListenerControl = func(network, address string, c syscall.RawConn) error {
+		called = true
+		return nil
+	}
+
+	ln, err := Listen("srt", "127.0.0.1:6003", config)
+	require.NoError(t, err)
+	defer ln.Close()
+
+	require.True(t, called, "ListenerControl callback was not invoked")
+}
+
 func TestListen(t *testing.T) {
 	ln, err := Listen("srt", "127.0.0.1:6003", DefaultConfig())
 	require.NoError(t, err)