6 files changed, 15 insertions, 16 deletions
diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go
index e51c5098c..c2bfd8c79 100644
--- a/pkg/tcpip/header/icmpv6.go
+++ b/pkg/tcpip/header/icmpv6.go
@@ -80,6 +80,13 @@ const (
 	// icmpv6SequenceOffset is the offset of the sequence field
 	// in a ICMPv6 Echo Request/Reply message.
 	icmpv6SequenceOffset = 6
+
+	// NDPHopLimit is the expected IP hop limit value of 255 for received
+	// NDP packets, as per RFC 4861 sections 4.1 - 4.5, 6.1.1, 6.1.2, 7.1.1,
+	// 7.1.2 and 8.1. If the hop limit value is not 255, nodes MUST silently
+	// drop the NDP packet. All outgoing NDP packets must use this value for
+	// its IP hop limit field.
+	NDPHopLimit = 255
 )
 
 // ICMPv6Type is the ICMP type field described in RFC 4443 and friends.
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index 7b638e9d0..6c14b4aae 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -21,15 +21,6 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
-const (
-	// ndpHopLimit is the expected IP hop limit value of 255 for received
-	// NDP packets, as per RFC 4861 sections 4.1 - 4.5, 6.1.1, 6.1.2, 7.1.1,
-	// 7.1.2 and 8.1. If the hop limit value is not 255, nodes MUST silently
-	// drop the NDP packet. All outgoing NDP packets must use this value for
-	// its IP hop limit field.
-	ndpHopLimit = 255
-)
-
 // handleControl handles the case when an ICMP packet contains the headers of
 // the original packet that caused the ICMP one to be sent. This information is
 // used to find out which transport endpoint must be notified about the ICMP
@@ -90,7 +81,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
 		header.ICMPv6RouterSolicit,
 		header.ICMPv6RouterAdvert,
 		header.ICMPv6RedirectMsg:
-		if iph.HopLimit() != ndpHopLimit {
+		if iph.HopLimit() != header.NDPHopLimit {
 			received.Invalid.Increment()
 			return
 		}
@@ -217,7 +208,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
 		//
 		// The IP Hop Limit field has a value of 255, i.e., the packet
 		// could not possibly have been forwarded by a router.
-		if err := r.WritePacket(nil /* gso */, hdr, buffer.VectorisedView{}, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: ndpHopLimit, TOS: stack.DefaultTOS}); err != nil {
+		if err := r.WritePacket(nil /* gso */, hdr, buffer.VectorisedView{}, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: stack.DefaultTOS}); err != nil {
 			sent.Dropped.Increment()
 			return
 		}
@@ -359,7 +350,7 @@ func (*protocol) LinkAddressRequest(addr, localAddr tcpip.Address, linkEP stack.
 	ip.Encode(&header.IPv6Fields{
 		PayloadLength: length,
 		NextHeader:    uint8(header.ICMPv6ProtocolNumber),
-		HopLimit:      ndpHopLimit,
+		HopLimit:      header.NDPHopLimit,
 		SrcAddr:       r.LocalAddress,
 		DstAddr:       r.RemoteAddress,
 	})
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index dd3c4d7c4..7c11dde55 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/pkg/tcpip/network/ipv6/icmp_test.go
@@ -143,7 +143,7 @@ func TestICMPCounts(t *testing.T) {
 		ip.Encode(&header.IPv6Fields{
 			PayloadLength: uint16(payloadLength),
 			NextHeader:    uint8(header.ICMPv6ProtocolNumber),
-			HopLimit:      ndpHopLimit,
+			HopLimit:      header.NDPHopLimit,
 			SrcAddr:       r.LocalAddress,
 			DstAddr:       r.RemoteAddress,
 		})
diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go
index e30791fe3..c32716f2e 100644
--- a/pkg/tcpip/network/ipv6/ndp_test.go
+++ b/pkg/tcpip/network/ipv6/ndp_test.go
@@ -150,7 +150,7 @@ func TestHopLimitValidation(t *testing.T) {
 
 			// Receive the NDP packet with an invalid hop limit
 			// value.
-			handleIPv6Payload(hdr, ndpHopLimit-1, ep, &r)
+			handleIPv6Payload(hdr, header.NDPHopLimit-1, ep, &r)
 
 			// Invalid count should have increased.
 			if got := invalid.Value(); got != 1 {
@@ -164,7 +164,7 @@ func TestHopLimitValidation(t *testing.T) {
 			}
 
 			// Receive the NDP packet with a valid hop limit value.
-			handleIPv6Payload(hdr, ndpHopLimit, ep, &r)
+			handleIPv6Payload(hdr, header.NDPHopLimit, ep, &r)
 
 			// Rx count of NDP packet of type typ.typ should have
 			// increased.
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index bed60d7b1..921d1c9c7 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -239,7 +239,7 @@ func (ndp *ndpState) doDuplicateAddressDetection(n *NIC, addr tcpip.Address, rem
 	pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{}))
 
 	sent := r.Stats().ICMP.V6PacketsSent
-	if err := r.WritePacket(nil, hdr, buffer.VectorisedView{}, NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: DefaultTOS}); err != nil {
+	if err := r.WritePacket(nil, hdr, buffer.VectorisedView{}, NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: DefaultTOS}); err != nil {
 		sent.Dropped.Increment()
 		return false, err
 	}
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index cc789d70f..849c2f35f 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -173,6 +173,7 @@ func TestDADResolve(t *testing.T) {
 
 				// Check NDP packet.
 				checker.IPv6(t, p.Header.ToVectorisedView().First(),
+					checker.TTL(header.NDPHopLimit),
 					checker.NDPNS(
 						checker.NDPNSTargetAddress(addr1)))
 			}