Merge release-20190806.1-270-gbfa0bb2 (automated)

21 files changed, 200 insertions, 42 deletions

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 09db2109f..0ae573b45 100755
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -1177,6 +1177,25 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf
 	case linux.IPV6_PATHMTU:
 		t.Kernel().EmitUnimplementedEvent(t)
 
+	case linux.IPV6_TCLASS:
+		// Length handling for parity with Linux.
+		if outLen == 0 {
+			return make([]byte, 0), nil
+		}
+		var v tcpip.IPv6TrafficClassOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+
+		uintv := uint32(v)
+		// Linux truncates the output binary to outLen.
+		ib := binary.Marshal(nil, usermem.ByteOrder, &uintv)
+		// Handle cases where outLen is lesser than sizeOfInt32.
+		if len(ib) > outLen {
+			ib = ib[:outLen]
+		}
+		return ib, nil
+
 	default:
 		emitUnimplementedEventIPv6(t, name)
 	}
@@ -1244,6 +1263,20 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in
 		}
 		return int32(0), nil
 
+	case linux.IP_TOS:
+		// Length handling for parity with Linux.
+		if outLen == 0 {
+			return []byte(nil), nil
+		}
+		var v tcpip.IPv4TOSOption
+		if err := ep.GetSockOpt(&v); err != nil {
+			return nil, syserr.TranslateNetstackError(err)
+		}
+		if outLen < sizeOfInt32 {
+			return uint8(v), nil
+		}
+		return int32(v), nil
+
 	default:
 		emitUnimplementedEventIP(t, name)
 	}
@@ -1542,6 +1575,19 @@ func setSockOptIPv6(t *kernel.Task, ep commonEndpoint, name int, optVal []byte)
 
 		t.Kernel().EmitUnimplementedEvent(t)
 
+	case linux.IPV6_TCLASS:
+		if len(optVal) < sizeOfInt32 {
+			return syserr.ErrInvalidArgument
+		}
+		v := int32(usermem.ByteOrder.Uint32(optVal))
+		if v < -1 || v > 255 {
+			return syserr.ErrInvalidArgument
+		}
+		if v == -1 {
+			v = 0
+		}
+		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.IPv6TrafficClassOption(v)))
+
 	default:
 		emitUnimplementedEventIPv6(t, name)
 	}
@@ -1687,6 +1733,16 @@ func setSockOptIP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *s
 		}
 		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.TTLOption(v)))
 
+	case linux.IP_TOS:
+		if len(optVal) == 0 {
+			return nil
+		}
+		v, err := parseIntOrChar(optVal)
+		if err != nil {
+			return err
+		}
+		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.IPv4TOSOption(v)))
+
 	case linux.IP_ADD_SOURCE_MEMBERSHIP,
 		linux.IP_BIND_ADDRESS_NO_PORT,
 		linux.IP_BLOCK_SOURCE,
@@ -1710,7 +1766,6 @@ func setSockOptIP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *s
 		linux.IP_RECVTOS,
 		linux.IP_RECVTTL,
 		linux.IP_RETOPTS,
-		linux.IP_TOS,
 		linux.IP_TRANSPARENT,
 		linux.IP_UNBLOCK_SOURCE,
 		linux.IP_UNICAST_IF,
diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index 26cf1c528..922181ac0 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -79,7 +79,7 @@ func (e *endpoint) MaxHeaderLength() uint16 {
 
 func (e *endpoint) Close() {}
 
-func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, buffer.Prependable, buffer.VectorisedView, tcpip.TransportProtocolNumber, uint8, stack.PacketLooping) *tcpip.Error {
+func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, buffer.Prependable, buffer.VectorisedView, stack.NetworkHeaderParams, stack.PacketLooping) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index c1cf6c222..50b363dc4 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -95,7 +95,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
 		pkt.SetChecksum(0)
 		pkt.SetChecksum(^header.Checksum(pkt, header.ChecksumVV(vv, 0)))
 		sent := stats.ICMP.V4PacketsSent
-		if err := r.WritePacket(nil /* gso */, hdr, vv, header.ICMPv4ProtocolNumber, 0, true /* useDefaultTTL */); err != nil {
+		if err := r.WritePacket(nil /* gso */, hdr, vv, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}); err != nil {
 			sent.Dropped.Increment()
 			return
 		}
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index fb6358fbb..df1a08113 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -199,21 +199,22 @@ func (e *endpoint) writePacketFragments(r *stack.Route, gso *stack.GSO, hdr buff
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8, loop stack.PacketLooping) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, params stack.NetworkHeaderParams, loop stack.PacketLooping) *tcpip.Error {
 	ip := header.IPv4(hdr.Prepend(header.IPv4MinimumSize))
 	length := uint16(hdr.UsedLength() + payload.Size())
 	id := uint32(0)
 	if length > header.IPv4MaximumHeaderSize+8 {
 		// Packets of 68 bytes or less are required by RFC 791 to not be
 		// fragmented, so we only assign ids to larger packets.
-		id = atomic.AddUint32(&e.protocol.ids[hashRoute(r, protocol, e.protocol.hashIV)%buckets], 1)
+		id = atomic.AddUint32(&e.protocol.ids[hashRoute(r, params.Protocol, e.protocol.hashIV)%buckets], 1)
 	}
 	ip.Encode(&header.IPv4Fields{
 		IHL:         header.IPv4MinimumSize,
 		TotalLength: length,
 		ID:          uint16(id),
-		TTL:         ttl,
-		Protocol:    uint8(protocol),
+		TTL:         params.TTL,
+		TOS:         params.TOS,
+		Protocol:    uint8(params.Protocol),
 		SrcAddr:     r.LocalAddress,
 		DstAddr:     r.RemoteAddress,
 	})
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index 71c398027..b5df85455 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -154,7 +154,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
 		r.LocalAddress = targetAddr
 		pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{}))
 
-		if err := r.WritePacket(nil /* gso */, hdr, buffer.VectorisedView{}, header.ICMPv6ProtocolNumber, 0, true /* useDefaultTTL */); err != nil {
+		if err := r.WritePacket(nil /* gso */, hdr, buffer.VectorisedView{}, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}); err != nil {
 			sent.Dropped.Increment()
 			return
 		}
@@ -185,7 +185,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
 		copy(pkt, h)
 		pkt.SetType(header.ICMPv6EchoReply)
 		pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, vv))
-		if err := r.WritePacket(nil /* gso */, hdr, vv, header.ICMPv6ProtocolNumber, 0, true /* useDefaultTTL */); err != nil {
+		if err := r.WritePacket(nil /* gso */, hdr, vv, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}); err != nil {
 			sent.Dropped.Increment()
 			return
 		}
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 85c070c43..cd1e34085 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -98,13 +98,14 @@ func (e *endpoint) GSOMaxSize() uint32 {
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8, loop stack.PacketLooping) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, params stack.NetworkHeaderParams, loop stack.PacketLooping) *tcpip.Error {
 	length := uint16(hdr.UsedLength() + payload.Size())
 	ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize))
 	ip.Encode(&header.IPv6Fields{
 		PayloadLength: length,
-		NextHeader:    uint8(protocol),
-		HopLimit:      ttl,
+		NextHeader:    uint8(params.Protocol),
+		HopLimit:      params.TTL,
+		TrafficClass:  params.TOS,
 		SrcAddr:       r.LocalAddress,
 		DstAddr:       r.RemoteAddress,
 	})
diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index 80101d4bb..9d6157f22 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -146,6 +146,19 @@ const (
 	PacketLoop
 )
 
+// NetworkHeaderParams are the header parameters given as input by the
+// transport endpoint to the network.
+type NetworkHeaderParams struct {
+	// Protocol refers to the transport protocol number.
+	Protocol tcpip.TransportProtocolNumber
+
+	// TTL refers to Time To Live field of the IP-header.
+	TTL uint8
+
+	// TOS refers to TypeOfService or TrafficClass field of the IP-header.
+	TOS uint8
+}
+
 // NetworkEndpoint is the interface that needs to be implemented by endpoints
 // of network layer protocols (e.g., ipv4, ipv6).
 type NetworkEndpoint interface {
@@ -170,7 +183,7 @@ type NetworkEndpoint interface {
 
 	// WritePacket writes a packet to the given destination address and
 	// protocol.
-	WritePacket(r *Route, gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8, loop PacketLooping) *tcpip.Error
+	WritePacket(r *Route, gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, params NetworkHeaderParams, loop PacketLooping) *tcpip.Error
 
 	// WriteHeaderIncludedPacket writes a packet that includes a network
 	// header to the given destination address.
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index 22db619a1..e72373964 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -154,16 +154,12 @@ func (r *Route) IsResolutionRequired() bool {
 }
 
 // WritePacket writes the packet through the given route.
-func (r *Route) WritePacket(gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8, useDefaultTTL bool) *tcpip.Error {
+func (r *Route) WritePacket(gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, params NetworkHeaderParams) *tcpip.Error {
 	if !r.ref.isValidForOutgoing() {
 		return tcpip.ErrInvalidEndpointState
 	}
 
-	if useDefaultTTL {
-		ttl = r.DefaultTTL()
-	}
-
-	err := r.ref.ep.WritePacket(r, gso, hdr, payload, protocol, ttl, r.loop)
+	err := r.ref.ep.WritePacket(r, gso, hdr, payload, params, r.loop)
 	if err != nil {
 		r.Stats().IP.OutgoingPacketErrors.Increment()
 	} else {
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 7d73389cc..f67975525 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -43,6 +43,9 @@ const (
 	resolutionTimeout = 1 * time.Second
 	// resolutionAttempts is set to the same ARP retries used in Linux.
 	resolutionAttempts = 3
+
+	// DefaultTOS is the default type of service value for network endpoints.
+	DefaultTOS = 0
 )
 
 type transportProtocolState struct {
@@ -394,7 +397,7 @@ type Stack struct {
 	// portSeed is a one-time random value initialized at stack startup
 	// and is used to seed the TCP port picking on active connections
 	//
-	// TODO(gvisor.dev/issues/940): S/R this field.
+	// TODO(gvisor.dev/issue/940): S/R this field.
 	portSeed uint32
 }
 
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 444ac1a5b..9d3752032 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -624,6 +624,14 @@ type BroadcastOption int
 // a default TTL.
 type DefaultTTLOption uint8
 
+// IPv4TOSOption is used by SetSockOpt/GetSockOpt to specify TOS
+// for all subsequent outgoing IPv4 packets from the endpoint.
+type IPv4TOSOption uint8
+
+// IPv6TrafficClassOption is used by SetSockOpt/GetSockOpt to specify TOS
+// for all subsequent outgoing IPv6 packets from the endpoint.
+type IPv6TrafficClassOption uint8
+
 // Route is a row in the routing table. It specifies through which NIC (and
 // gateway) sets of packets should be routed. A row is considered viable if the
 // masked target address matches the destination address in the row.
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index d0cfdcda1..3187b336b 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -422,7 +422,10 @@ func send4(r *stack.Route, ident uint16, data buffer.View, ttl uint8) *tcpip.Err
 	icmpv4.SetChecksum(0)
 	icmpv4.SetChecksum(^header.Checksum(icmpv4, header.Checksum(data, 0)))
 
-	return r.WritePacket(nil /* gso */, hdr, data.ToVectorisedView(), header.ICMPv4ProtocolNumber, ttl, ttl == 0 /* useDefaultTTL */)
+	if ttl == 0 {
+		ttl = r.DefaultTTL()
+	}
+	return r.WritePacket(nil /* gso */, hdr, data.ToVectorisedView(), stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: ttl, TOS: stack.DefaultTOS})
 }
 
 func send6(r *stack.Route, ident uint16, data buffer.View, ttl uint8) *tcpip.Error {
@@ -445,7 +448,10 @@ func send6(r *stack.Route, ident uint16, data buffer.View, ttl uint8) *tcpip.Err
 	icmpv6.SetChecksum(0)
 	icmpv6.SetChecksum(^header.Checksum(icmpv6, header.Checksum(data, 0)))
 
-	return r.WritePacket(nil /* gso */, hdr, data.ToVectorisedView(), header.ICMPv6ProtocolNumber, ttl, ttl == 0 /* useDefaultTTL */)
+	if ttl == 0 {
+		ttl = r.DefaultTTL()
+	}
+	return r.WritePacket(nil /* gso */, hdr, data.ToVectorisedView(), stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: ttl, TOS: stack.DefaultTOS})
 }
 
 func (e *endpoint) checkV4Mapped(addr *tcpip.FullAddress, allowMismatch bool) (tcpip.NetworkProtocolNumber, *tcpip.Error) {
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 4f5c286cf..b4c660859 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -350,7 +350,7 @@ func (e *endpoint) finishWrite(payloadBytes []byte, route *stack.Route) (int64,
 			break
 		}
 		hdr := buffer.NewPrependable(len(payloadBytes) + int(route.MaxHeaderLength()))
-		if err := route.WritePacket(nil /* gso */, hdr, buffer.View(payloadBytes).ToVectorisedView(), e.TransProto, 0, true /* useDefaultTTL */); err != nil {
+		if err := route.WritePacket(nil /* gso */, hdr, buffer.View(payloadBytes).ToVectorisedView(), stack.NetworkHeaderParams{Protocol: e.TransProto, TTL: route.DefaultTTL(), TOS: stack.DefaultTOS}); err != nil {
 			return 0, nil, err
 		}
 
diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go
index 8f5572195..844959fa0 100644
--- a/pkg/tcpip/transport/tcp/accept.go
+++ b/pkg/tcpip/transport/tcp/accept.go
@@ -441,7 +441,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
 				TSEcr: opts.TSVal,
 				MSS:   uint16(mss),
 			}
-			e.sendSynTCP(&s.route, s.id, e.ttl, header.TCPFlagSyn|header.TCPFlagAck, cookie, s.sequenceNumber+1, ctx.rcvWnd, synOpts)
+			e.sendSynTCP(&s.route, s.id, e.ttl, e.sendTOS, header.TCPFlagSyn|header.TCPFlagAck, cookie, s.sequenceNumber+1, ctx.rcvWnd, synOpts)
 			e.stack.Stats().TCP.ListenOverflowSynCookieSent.Increment()
 		}
 
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index cb8cfd619..5ea036bea 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -255,7 +255,7 @@ func (h *handshake) synSentState(s *segment) *tcpip.Error {
 	if ttl == 0 {
 		ttl = s.route.DefaultTTL()
 	}
-	h.ep.sendSynTCP(&s.route, h.ep.ID, ttl, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
+	h.ep.sendSynTCP(&s.route, h.ep.ID, ttl, h.ep.sendTOS, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
 	return nil
 }
 
@@ -299,7 +299,7 @@ func (h *handshake) synRcvdState(s *segment) *tcpip.Error {
 			SACKPermitted: h.ep.sackPermitted,
 			MSS:           h.ep.amss,
 		}
-		h.ep.sendSynTCP(&s.route, h.ep.ID, h.ep.ttl, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
+		h.ep.sendSynTCP(&s.route, h.ep.ID, h.ep.ttl, h.ep.sendTOS, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
 		return nil
 	}
 
@@ -468,7 +468,8 @@ func (h *handshake) execute() *tcpip.Error {
 			synOpts.WS = -1
 		}
 	}
-	h.ep.sendSynTCP(&h.ep.route, h.ep.ID, h.ep.ttl, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
+	h.ep.sendSynTCP(&h.ep.route, h.ep.ID, h.ep.ttl, h.ep.sendTOS, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
+
 	for h.state != handshakeCompleted {
 		switch index, _ := s.Fetch(true); index {
 		case wakerForResend:
@@ -477,7 +478,7 @@ func (h *handshake) execute() *tcpip.Error {
 				return tcpip.ErrTimeout
 			}
 			rt.Reset(timeOut)
-			h.ep.sendSynTCP(&h.ep.route, h.ep.ID, h.ep.ttl, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
+			h.ep.sendSynTCP(&h.ep.route, h.ep.ID, h.ep.ttl, h.ep.sendTOS, h.flags, h.iss, h.ackNum, h.rcvWnd, synOpts)
 
 		case wakerForNotification:
 			n := h.ep.fetchNotifications()
@@ -587,17 +588,18 @@ func makeSynOptions(opts header.TCPSynOptions) []byte {
 	return options[:offset]
 }
 
-func (e *endpoint) sendSynTCP(r *stack.Route, id stack.TransportEndpointID, ttl uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts header.TCPSynOptions) {
+func (e *endpoint) sendSynTCP(r *stack.Route, id stack.TransportEndpointID, ttl, tos uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts header.TCPSynOptions) *tcpip.Error {
 	options := makeSynOptions(opts)
 	// We ignore SYN send errors and let the callers re-attempt send.
-	if err := e.sendTCP(r, id, buffer.VectorisedView{}, ttl, flags, seq, ack, rcvWnd, options, nil); err != nil {
+	if err := e.sendTCP(r, id, buffer.VectorisedView{}, ttl, tos, flags, seq, ack, rcvWnd, options, nil); err != nil {
 		e.stats.SendErrors.SynSendToNetworkFailed.Increment()
 	}
 	putOptions(options)
+	return nil
 }
 
-func (e *endpoint) sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.VectorisedView, ttl uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts []byte, gso *stack.GSO) *tcpip.Error {
-	if err := sendTCP(r, id, data, ttl, flags, seq, ack, rcvWnd, opts, gso); err != nil {
+func (e *endpoint) sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.VectorisedView, ttl, tos uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts []byte, gso *stack.GSO) *tcpip.Error {
+	if err := sendTCP(r, id, data, ttl, tos, flags, seq, ack, rcvWnd, opts, gso); err != nil {
 		e.stats.SendErrors.SegmentSendToNetworkFailed.Increment()
 		return err
 	}
@@ -607,7 +609,7 @@ func (e *endpoint) sendTCP(r *stack.Route, id stack.TransportEndpointID, data bu
 
 // sendTCP sends a TCP segment with the provided options via the provided
 // network endpoint and under the provided identity.
-func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.VectorisedView, ttl uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts []byte, gso *stack.GSO) *tcpip.Error {
+func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.VectorisedView, ttl, tos uint8, flags byte, seq, ack seqnum.Value, rcvWnd seqnum.Size, opts []byte, gso *stack.GSO) *tcpip.Error {
 	optLen := len(opts)
 	// Allocate a buffer for the TCP header.
 	hdr := buffer.NewPrependable(header.TCPMinimumSize + int(r.MaxHeaderLength()) + optLen)
@@ -643,7 +645,10 @@ func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.Vectorise
 		tcp.SetChecksum(^tcp.CalculateChecksum(xsum))
 	}
 
-	if err := r.WritePacket(gso, hdr, data, ProtocolNumber, ttl, ttl == 0 /* useDefaultTTL */); err != nil {
+	if ttl == 0 {
+		ttl = r.DefaultTTL()
+	}
+	if err := r.WritePacket(gso, hdr, data, stack.NetworkHeaderParams{Protocol: ProtocolNumber, TTL: ttl, TOS: tos}); err != nil {
 		r.Stats().TCP.SegmentSendErrors.Increment()
 		return err
 	}
@@ -700,7 +705,7 @@ func (e *endpoint) sendRaw(data buffer.VectorisedView, flags byte, seq, ack seqn
 		sackBlocks = e.sack.Blocks[:e.sack.NumBlocks]
 	}
 	options := e.makeOptions(sackBlocks)
-	err := e.sendTCP(&e.route, e.ID, data, e.ttl, flags, seq, ack, rcvWnd, options, e.gso)
+	err := e.sendTCP(&e.route, e.ID, data, e.ttl, e.sendTOS, flags, seq, ack, rcvWnd, options, e.gso)
 	putOptions(options)
 	return err
 }
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 090a8eb24..a1b784b49 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -494,6 +494,10 @@ type endpoint struct {
 	// amss is the advertised MSS to the peer by this endpoint.
 	amss uint16
 
+	// sendTOS represents IPv4 TOS or IPv6 TrafficClass,
+	// applied while sending packets. Defaults to 0 as on Linux.
+	sendTOS uint8
+
 	gso *stack.GSO
 
 	// TODO(b/142022063): Add ability to save and restore per endpoint stats.
@@ -1136,6 +1140,8 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
 
 // SetSockOpt sets a socket option.
 func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
+	// Lower 2 bits represents ECN bits. RFC 3168, section 23.1
+	const inetECNMask = 3
 	switch v := opt.(type) {
 	case tcpip.DelayOption:
 		if v == 0 {
@@ -1296,6 +1302,23 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		// Linux returns ENOENT when an invalid congestion
 		// control algorithm is specified.
 		return tcpip.ErrNoSuchFile
+
+	case tcpip.IPv4TOSOption:
+		e.mu.Lock()
+		// TODO(gvisor.dev/issue/995): ECN is not currently supported,
+		// ignore the bits for now.
+		e.sendTOS = uint8(v) & ^uint8(inetECNMask)
+		e.mu.Unlock()
+		return nil
+
+	case tcpip.IPv6TrafficClassOption:
+		e.mu.Lock()
+		// TODO(gvisor.dev/issue/995): ECN is not currently supported,
+		// ignore the bits for now.
+		e.sendTOS = uint8(v) & ^uint8(inetECNMask)
+		e.mu.Unlock()
+		return nil
+
 	default:
 		return nil
 	}
@@ -1495,6 +1518,18 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 		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
 	}
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index d5d8ab96a..db40785d3 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -153,7 +153,7 @@ func replyWithReset(s *segment) {
 
 	ack := s.sequenceNumber.Add(s.logicalLen())
 
-	sendTCP(&s.route, s.id, buffer.VectorisedView{}, s.route.DefaultTTL(), header.TCPFlagRst|header.TCPFlagAck, seq, ack, 0, nil /* options */, nil /* gso */)
+	sendTCP(&s.route, s.id, buffer.VectorisedView{}, s.route.DefaultTTL(), stack.DefaultTOS, header.TCPFlagRst|header.TCPFlagAck, seq, ack, 0 /* rcvWnd */, nil /* options */, nil /* gso */)
 }
 
 // SetOption implements TransportProtocol.SetOption.
diff --git a/pkg/tcpip/transport/tcp/tcp_state_autogen.go b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
index 53c6cdb24..57eb0ad58 100755
--- a/pkg/tcpip/transport/tcp/tcp_state_autogen.go
+++ b/pkg/tcpip/transport/tcp/tcp_state_autogen.go
@@ -141,6 +141,7 @@ func (x *endpoint) save(m state.Map) {
 	m.Save("snd", &x.snd)
 	m.Save("connectingAddress", &x.connectingAddress)
 	m.Save("amss", &x.amss)
+	m.Save("sendTOS", &x.sendTOS)
 	m.Save("gso", &x.gso)
 }
 
@@ -189,6 +190,7 @@ func (x *endpoint) load(m state.Map) {
 	m.LoadWait("snd", &x.snd)
 	m.Load("connectingAddress", &x.connectingAddress)
 	m.Load("amss", &x.amss)
+	m.Load("sendTOS", &x.sendTOS)
 	m.Load("gso", &x.gso)
 	m.LoadValue("lastError", new(string), func(y interface{}) { x.loadLastError(y.(string)) })
 	m.LoadValue("state", new(EndpointState), func(y interface{}) { x.loadState(y.(EndpointState)) })
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)
diff --git a/runsc/cmd/gofer.go b/runsc/cmd/gofer.go
index fbd579fb8..4c2fb80bf 100644
--- a/runsc/cmd/gofer.go
+++ b/runsc/cmd/gofer.go
@@ -423,7 +423,7 @@ func resolveSymlinksImpl(root, base, rel string, followCount uint) (string, erro
 		path := filepath.Join(base, name)
 		if !strings.HasPrefix(path, root) {
 			// One cannot '..' their way out of root.
-			path = root
+			base = root
 			continue
 		}
 		fi, err := os.Lstat(path)