ipv6: ICMP support

This CL does NDP link-address discovery for IPv6.

It includes several small changes necessary to get linux to talk to
this implementation. In particular, a hop limit of 255 is necessary
for ICMPv6.

PiperOrigin-RevId: 211103930
Change-Id: If25370ab84c6b1decfb15de917f3b0020f2c4e0e

1 files changed, 16 insertions, 14 deletions

diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index f48d120c5..51d34b7ec 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -42,18 +42,12 @@ const (
 type address [header.IPv6AddressSize]byte
 
 type endpoint struct {
-	nicid      tcpip.NICID
-	id         stack.NetworkEndpointID
-	address    address
-	linkEP     stack.LinkEndpoint
-	dispatcher stack.TransportDispatcher
-}
-
-func newEndpoint(nicid tcpip.NICID, addr tcpip.Address, dispatcher stack.TransportDispatcher, linkEP stack.LinkEndpoint) *endpoint {
-	e := &endpoint{nicid: nicid, linkEP: linkEP, dispatcher: dispatcher}
-	copy(e.address[:], addr)
-	e.id = stack.NetworkEndpointID{tcpip.Address(e.address[:])}
-	return e
+	nicid         tcpip.NICID
+	id            stack.NetworkEndpointID
+	address       address
+	linkEP        stack.LinkEndpoint
+	linkAddrCache stack.LinkAddressCache
+	dispatcher    stack.TransportDispatcher
 }
 
 // MTU implements stack.NetworkEndpoint.MTU. It returns the link-layer MTU minus
@@ -93,7 +87,7 @@ func (e *endpoint) WritePacket(r *stack.Route, hdr *buffer.Prependable, payload
 	ip.Encode(&header.IPv6Fields{
 		PayloadLength: length,
 		NextHeader:    uint8(protocol),
-		HopLimit:      65,
+		HopLimit:      icmpV6HopLimit,
 		SrcAddr:       tcpip.Address(e.address[:]),
 		DstAddr:       r.RemoteAddress,
 	})
@@ -154,7 +148,15 @@ func (*protocol) ParseAddresses(v buffer.View) (src, dst tcpip.Address) {
 
 // NewEndpoint creates a new ipv6 endpoint.
 func (p *protocol) NewEndpoint(nicid tcpip.NICID, addr tcpip.Address, linkAddrCache stack.LinkAddressCache, dispatcher stack.TransportDispatcher, linkEP stack.LinkEndpoint) (stack.NetworkEndpoint, *tcpip.Error) {
-	return newEndpoint(nicid, addr, dispatcher, linkEP), nil
+	e := &endpoint{
+		nicid:         nicid,
+		linkEP:        linkEP,
+		linkAddrCache: linkAddrCache,
+		dispatcher:    dispatcher,
+	}
+	copy(e.address[:], addr)
+	e.id = stack.NetworkEndpointID{LocalAddress: tcpip.Address(e.address[:])}
+	return e, nil
 }
 
 // SetOption implements NetworkProtocol.SetOption.