restore Windows compatibility (#860) (#861)

client_udp_listener.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/bluenviron/gortsplib/v4/pkg/multicast"
+	"github.com/bluenviron/gortsplib/v4/pkg/readbuffer"
 )
 
 func int64Ptr(v int64) *int64 {
@@ -28,42 +29,7 @@ func randInRange(maxVal int) (int, error) {
 type packetConn interface {
 	net.PacketConn
 	SyscallConn() (syscall.RawConn, error)
-}
-
-func setAndVerifyReadBufferSize(pc packetConn, v int) error {
-	rawConn, err := pc.SyscallConn()
-	if err != nil {
-		panic(err)
-	}
-
-	var err2 error
-
-	err = rawConn.Control(func(fd uintptr) {
-		err2 = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_RCVBUF, v)
-		if err2 != nil {
-			return
-		}
-
-		var v2 int
-		v2, err2 = syscall.GetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_RCVBUF)
-		if err2 != nil {
-			return
-		}
-
-		if v2 != (v * 2) {
-			err2 = fmt.Errorf("unable to set read buffer size to %v - check that net.core.rmem_max is greater than %v", v, v)
-			return
-		}
-	})
-	if err != nil {
-		return err
-	}
-
-	if err2 != nil {
-		return err2
-	}
-
-	return nil
+	SetReadBuffer(bytes int) error
 }
 
 type clientUDPListener struct {
@@ -100,11 +66,23 @@ func (u *clientUDPListener) initialize() error {
 	}
 
 	if u.c.UDPReadBufferSize != 0 {
-		err := setAndVerifyReadBufferSize(u.pc, u.c.UDPReadBufferSize)
+		err := u.pc.SetReadBuffer(u.c.UDPReadBufferSize)
 		if err != nil {
 			u.pc.Close()
 			return err
 		}
+
+		v, err := readbuffer.ReadBuffer(u.pc)
+		if err != nil {
+			u.pc.Close()
+			return err
+		}
+
+		if v != u.c.UDPReadBufferSize {
+			u.pc.Close()
+			return fmt.Errorf("unable to set read buffer size to %v, check that the operating system allows that",
+				u.c.UDPReadBufferSize)
+		}
 	}
 
 	u.lastPacketTime = int64Ptr(0)

pkg/readbuffer/read_buffer.go

@@ -0,0 +1,13 @@
+// Package readbuffer contains a function to get the read buffer size of a socket.
+package readbuffer
+
+import (
+	"net"
+	"syscall"
+)
+
+// PacketConn is a packet connection.
+type PacketConn interface {
+	net.PacketConn
+	SyscallConn() (syscall.RawConn, error)
+}

pkg/readbuffer/read_buffer_lin.go

@@ -0,0 +1,31 @@
+//go:build linux
+
+package readbuffer
+
+import (
+	"syscall"
+)
+
+// ReadBuffer returns the read buffer size.
+func ReadBuffer(pc PacketConn) (int, error) {
+	rawConn, err := pc.SyscallConn()
+	if err != nil {
+		panic(err)
+	}
+
+	var v int
+	var err2 error
+
+	err = rawConn.Control(func(fd uintptr) {
+		v, err2 = syscall.GetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_RCVBUF)
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	if err2 != nil {
+		return 0, err2
+	}
+
+	return v / 2, nil
+}

pkg/readbuffer/read_buffer_other.go

@@ -0,0 +1,10 @@
+//go:build !linux && !windows
+
+package readbuffer
+
+import "fmt"
+
+// ReadBuffer returns the read buffer size.
+func ReadBuffer(pc PacketConn) (int, error) {
+	return 0, fmt.Errorf("read buffer size is unimplemented on the current operating system")
+}

pkg/readbuffer/read_buffer_win.go

@@ -0,0 +1,29 @@
+//go:build windows
+
+package readbuffer
+
+import "syscall"
+
+// ReadBuffer returns the read buffer size.
+func ReadBuffer(pc PacketConn) (int, error) {
+	rawConn, err := pc.SyscallConn()
+	if err != nil {
+		panic(err)
+	}
+
+	var v int
+	var err2 error
+
+	err = rawConn.Control(func(fd uintptr) {
+		v, err2 = syscall.GetsockoptInt(syscall.Handle(fd), syscall.SOL_SOCKET, syscall.SO_RCVBUF)
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	if err2 != nil {
+		return 0, err2
+	}
+
+	return v, nil
+}

server_udp_listener.go

@@ -1,12 +1,14 @@
 package gortsplib
 
 import (
+	"fmt"
 	"net"
 	"strconv"
 	"sync"
 	"time"
 
 	"github.com/bluenviron/gortsplib/v4/pkg/multicast"
+	"github.com/bluenviron/gortsplib/v4/pkg/readbuffer"
 )
 
 type clientAddr struct {
@@ -99,11 +101,23 @@ func (u *serverUDPListener) initialize() error {
 	}
 
 	if u.readBufferSize != 0 {
-		err := setAndVerifyReadBufferSize(u.pc, u.readBufferSize)
+		err := u.pc.SetReadBuffer(u.readBufferSize)
 		if err != nil {
 			u.pc.Close()
 			return err
 		}
+
+		v, err := readbuffer.ReadBuffer(u.pc)
+		if err != nil {
+			u.pc.Close()
+			return err
+		}
+
+		if v != u.readBufferSize {
+			u.pc.Close()
+			return fmt.Errorf("unable to set read buffer size to %v, check that the operating system allows that",
+				u.readBufferSize)
+		}
 	}
 
 	u.clients = make(map[clientAddr]readFunc)