3 files changed, 38 insertions, 5 deletions

diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 2ad7978c2..6e87245b7 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -106,6 +106,10 @@ type endpoint struct {
 	bindToDevice   tcpip.NICID
 	broadcast      bool
 
+	// sendTOS represents IPv4 TOS or IPv6 TrafficClass,
+	// applied while sending packets. Defaults to 0 as on Linux.
+	sendTOS uint8
+
 	// shutdownFlags represent the current shutdown state of the endpoint.
 	shutdownFlags tcpip.ShutdownFlags
 
@@ -429,7 +433,7 @@ func (e *endpoint) write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c
 		useDefaultTTL = false
 	}
 
-	if err := sendUDP(route, buffer.View(v).ToVectorisedView(), e.ID.LocalPort, dstPort, ttl, useDefaultTTL); err != nil {
+	if err := sendUDP(route, buffer.View(v).ToVectorisedView(), e.ID.LocalPort, dstPort, ttl, useDefaultTTL, e.sendTOS); err != nil {
 		return 0, nil, err
 	}
 	return int64(len(v)), nil, nil
@@ -628,6 +632,18 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 
 		return nil
+
+	case tcpip.IPv4TOSOption:
+		e.mu.Lock()
+		e.sendTOS = uint8(v)
+		e.mu.Unlock()
+		return nil
+
+	case tcpip.IPv6TrafficClassOption:
+		e.mu.Lock()
+		e.sendTOS = uint8(v)
+		e.mu.Unlock()
+		return nil
 	}
 	return nil
 }
@@ -748,6 +764,18 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
+	case *tcpip.IPv4TOSOption:
+		e.mu.RLock()
+		*o = tcpip.IPv4TOSOption(e.sendTOS)
+		e.mu.RUnlock()
+		return nil
+
+	case *tcpip.IPv6TrafficClassOption:
+		e.mu.RLock()
+		*o = tcpip.IPv6TrafficClassOption(e.sendTOS)
+		e.mu.RUnlock()
+		return nil
+
 	default:
 		return tcpip.ErrUnknownProtocolOption
 	}
@@ -755,7 +783,7 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 
 // sendUDP sends a UDP segment via the provided network endpoint and under the
 // provided identity.
-func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort uint16, ttl uint8, useDefaultTTL bool) *tcpip.Error {
+func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort uint16, ttl uint8, useDefaultTTL bool, tos uint8) *tcpip.Error {
 	// Allocate a buffer for the UDP header.
 	hdr := buffer.NewPrependable(header.UDPMinimumSize + int(r.MaxHeaderLength()))
 
@@ -778,7 +806,10 @@ func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort u
 		udp.SetChecksum(^udp.CalculateChecksum(xsum))
 	}
 
-	if err := r.WritePacket(nil /* gso */, hdr, data, ProtocolNumber, ttl, useDefaultTTL); err != nil {
+	if useDefaultTTL {
+		ttl = r.DefaultTTL()
+	}
+	if err := r.WritePacket(nil /* gso */, hdr, data, stack.NetworkHeaderParams{Protocol: ProtocolNumber, TTL: ttl, TOS: tos}); err != nil {
 		r.Stats().UDP.PacketSendErrors.Increment()
 		return err
 	}
diff --git a/pkg/tcpip/transport/udp/protocol.go b/pkg/tcpip/transport/udp/protocol.go
index 0b24bbc85..de026880f 100644
--- a/pkg/tcpip/transport/udp/protocol.go
+++ b/pkg/tcpip/transport/udp/protocol.go
@@ -130,7 +130,7 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans
 		pkt.SetType(header.ICMPv4DstUnreachable)
 		pkt.SetCode(header.ICMPv4PortUnreachable)
 		pkt.SetChecksum(header.ICMPv4Checksum(pkt, payload))
-		r.WritePacket(nil /* gso */, hdr, payload, header.ICMPv4ProtocolNumber, 0, true /* useDefaultTTL */)
+		r.WritePacket(nil /* gso */, hdr, payload, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS})
 
 	case header.IPv6AddressSize:
 		if !r.Stack().AllowICMPMessage() {
@@ -164,7 +164,7 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans
 		pkt.SetType(header.ICMPv6DstUnreachable)
 		pkt.SetCode(header.ICMPv6PortUnreachable)
 		pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, payload))
-		r.WritePacket(nil /* gso */, hdr, payload, header.ICMPv6ProtocolNumber, 0, true /* useDefaultTTL */)
+		r.WritePacket(nil /* gso */, hdr, payload, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS})
 	}
 	return true
 }
diff --git a/pkg/tcpip/transport/udp/udp_state_autogen.go b/pkg/tcpip/transport/udp/udp_state_autogen.go
index ca3fccc4b..bd811ed5c 100755
--- a/pkg/tcpip/transport/udp/udp_state_autogen.go
+++ b/pkg/tcpip/transport/udp/udp_state_autogen.go
@@ -47,6 +47,7 @@ func (x *endpoint) save(m state.Map) {
 	m.Save("reusePort", &x.reusePort)
 	m.Save("bindToDevice", &x.bindToDevice)
 	m.Save("broadcast", &x.broadcast)
+	m.Save("sendTOS", &x.sendTOS)
 	m.Save("shutdownFlags", &x.shutdownFlags)
 	m.Save("multicastMemberships", &x.multicastMemberships)
 	m.Save("effectiveNetProtos", &x.effectiveNetProtos)
@@ -71,6 +72,7 @@ func (x *endpoint) load(m state.Map) {
 	m.Load("reusePort", &x.reusePort)
 	m.Load("bindToDevice", &x.bindToDevice)
 	m.Load("broadcast", &x.broadcast)
+	m.Load("sendTOS", &x.sendTOS)
 	m.Load("shutdownFlags", &x.shutdownFlags)
 	m.Load("multicastMemberships", &x.multicastMemberships)
 	m.Load("effectiveNetProtos", &x.effectiveNetProtos)