4 files changed, 156 insertions, 9 deletions
diff --git a/pkg/tcpip/header/ndp_neighbor_advert.go b/pkg/tcpip/header/ndp_neighbor_advert.go
index 5c2b472c8..505c92668 100755
--- a/pkg/tcpip/header/ndp_neighbor_advert.go
+++ b/pkg/tcpip/header/ndp_neighbor_advert.go
@@ -18,6 +18,8 @@ import "gvisor.dev/gvisor/pkg/tcpip"
 
 // NDPNeighborAdvert is an NDP Neighbor Advertisement message. It will
 // only contain the body of an ICMPv6 packet.
+//
+// See RFC 4861 section 4.4 for more details.
 type NDPNeighborAdvert []byte
 
 const (
diff --git a/pkg/tcpip/header/ndp_neighbor_solicit.go b/pkg/tcpip/header/ndp_neighbor_solicit.go
index 1dcb0fbc6..3a1b8e139 100755
--- a/pkg/tcpip/header/ndp_neighbor_solicit.go
+++ b/pkg/tcpip/header/ndp_neighbor_solicit.go
@@ -18,6 +18,8 @@ import "gvisor.dev/gvisor/pkg/tcpip"
 
 // NDPNeighborSolicit is an NDP Neighbor Solicitation message. It will only
 // contain the body of an ICMPv6 packet.
+//
+// See RFC 4861 section 4.3 for more details.
 type NDPNeighborSolicit []byte
 
 const (
diff --git a/pkg/tcpip/header/ndp_router_advert.go b/pkg/tcpip/header/ndp_router_advert.go
new file mode 100755
index 000000000..bf7610863
--- /dev/null
+++ b/pkg/tcpip/header/ndp_router_advert.go
@@ -0,0 +1,112 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package header
+
+import (
+	"encoding/binary"
+	"time"
+)
+
+// NDPRouterAdvert is an NDP Router Advertisement message. It will only contain
+// the body of an ICMPv6 packet.
+//
+// See RFC 4861 section 4.2 for more details.
+type NDPRouterAdvert []byte
+
+const (
+	// NDPRAMinimumSize is the minimum size of a valid NDP Router
+	// Advertisement message (body of an ICMPv6 packet).
+	NDPRAMinimumSize = 12
+
+	// ndpRACurrHopLimitOffset is the byte of the Curr Hop Limit field
+	// within an NDPRouterAdvert.
+	ndpRACurrHopLimitOffset = 0
+
+	// ndpRAFlagsOffset is the byte with the NDP RA bit-fields/flags
+	// within an NDPRouterAdvert.
+	ndpRAFlagsOffset = 1
+
+	// ndpRAManagedAddrConfFlagMask is the mask of the Managed Address
+	// Configuration flag within the bit-field/flags byte of an
+	// NDPRouterAdvert.
+	ndpRAManagedAddrConfFlagMask = (1 << 7)
+
+	// ndpRAOtherConfFlagMask is the mask of the Other Configuration flag
+	// within the bit-field/flags byte of an NDPRouterAdvert.
+	ndpRAOtherConfFlagMask = (1 << 6)
+
+	// ndpRARouterLifetimeOffset is the start of the 2-byte Router Lifetime
+	// field within an NDPRouterAdvert.
+	ndpRARouterLifetimeOffset = 2
+
+	// ndpRAReachableTimeOffset is the start of the 4-byte Reachable Time
+	// field within an NDPRouterAdvert.
+	ndpRAReachableTimeOffset = 4
+
+	// ndpRARetransTimerOffset is the start of the 4-byte Retrans Timer
+	// field within an NDPRouterAdvert.
+	ndpRARetransTimerOffset = 8
+
+	// ndpRAOptionsOffset is the start of the NDP options in an
+	// NDPRouterAdvert.
+	ndpRAOptionsOffset = 12
+)
+
+// CurrHopLimit returns the value of the Curr Hop Limit field.
+func (b NDPRouterAdvert) CurrHopLimit() uint8 {
+	return b[ndpRACurrHopLimitOffset]
+}
+
+// ManagedAddrConfFlag returns the value of the Managed Address Configuration
+// flag.
+func (b NDPRouterAdvert) ManagedAddrConfFlag() bool {
+	return b[ndpRAFlagsOffset]&ndpRAManagedAddrConfFlagMask != 0
+}
+
+// OtherConfFlag returns the value of the Other Configuration flag.
+func (b NDPRouterAdvert) OtherConfFlag() bool {
+	return b[ndpRAFlagsOffset]&ndpRAOtherConfFlagMask != 0
+}
+
+// RouterLifetime returns the lifetime associated with the default router. A
+// value of 0 means the source of the Router Advertisement is not a default
+// router and SHOULD NOT appear on the default router list. Note, a value of 0
+// only means that the router should not be used as a default router, it does
+// not apply to other information contained in the Router Advertisement.
+func (b NDPRouterAdvert) RouterLifetime() time.Duration {
+	// The field is the time in seconds, as per RFC 4861 section 4.2.
+	return time.Second * time.Duration(binary.BigEndian.Uint16(b[ndpRARouterLifetimeOffset:]))
+}
+
+// ReachableTime returns the time that a node assumes a neighbor is reachable
+// after having received a reachability confirmation. A value of 0 means
+// that it is unspecified by the source of the Router Advertisement message.
+func (b NDPRouterAdvert) ReachableTime() time.Duration {
+	// The field is the time in milliseconds, as per RFC 4861 section 4.2.
+	return time.Millisecond * time.Duration(binary.BigEndian.Uint32(b[ndpRAReachableTimeOffset:]))
+}
+
+// RetransTimer returns the time between retransmitted Neighbor Solicitation
+// messages. A value of 0 means that it is unspecified by the source of the
+// Router Advertisement message.
+func (b NDPRouterAdvert) RetransTimer() time.Duration {
+	// The field is the time in milliseconds, as per RFC 4861 section 4.2.
+	return time.Millisecond * time.Duration(binary.BigEndian.Uint32(b[ndpRARetransTimerOffset:]))
+}
+
+// Options returns an NDPOptions of the the options body.
+func (b NDPRouterAdvert) Options() NDPOptions {
+	return NDPOptions(b[ndpRAOptionsOffset:])
+}
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 9be3f6ee4..e456e05f4 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -335,9 +335,31 @@ func (n *NIC) addPermanentAddressLocked(protocolAddress tcpip.ProtocolAddress, p
 			// The NIC already have a permanent endpoint with that address.
 			return nil, tcpip.ErrDuplicateAddress
 		case permanentExpired, temporary:
-			// Promote the endpoint to become permanent.
+			// Promote the endpoint to become permanent and respect
+			// the new peb.
 			if ref.tryIncRef() {
 				ref.setKind(permanent)
+
+				refs := n.primary[ref.protocol]
+				for i, r := range refs {
+					if r == ref {
+						switch peb {
+						case CanBePrimaryEndpoint:
+							return ref, nil
+						case FirstPrimaryEndpoint:
+							if i == 0 {
+								return ref, nil
+							}
+							n.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
+						case NeverPrimaryEndpoint:
+							n.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
+							return ref, nil
+						}
+					}
+				}
+
+				n.insertPrimaryEndpointLocked(ref, peb)
+
 				return ref, nil
 			}
 			// tryIncRef failing means the endpoint is scheduled to be removed once
@@ -406,12 +428,7 @@ func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb Primar
 
 	n.endpoints[id] = ref
 
-	switch peb {
-	case CanBePrimaryEndpoint:
-		n.primary[protocolAddress.Protocol] = append(n.primary[protocolAddress.Protocol], ref)
-	case FirstPrimaryEndpoint:
-		n.primary[protocolAddress.Protocol] = append([]*referencedNetworkEndpoint{ref}, n.primary[protocolAddress.Protocol]...)
-	}
+	n.insertPrimaryEndpointLocked(ref, peb)
 
 	// If we are adding a tentative IPv6 address, start DAD.
 	if isIPv6Unicast && kind == permanentTentative {
@@ -533,6 +550,19 @@ func (n *NIC) AddressRanges() []tcpip.Subnet {
 	return append(sns, n.addressRanges...)
 }
 
+// insertPrimaryEndpointLocked adds r to n's primary endpoint list as required
+// by peb.
+//
+// n MUST be locked.
+func (n *NIC) insertPrimaryEndpointLocked(r *referencedNetworkEndpoint, peb PrimaryEndpointBehavior) {
+	switch peb {
+	case CanBePrimaryEndpoint:
+		n.primary[r.protocol] = append(n.primary[r.protocol], r)
+	case FirstPrimaryEndpoint:
+		n.primary[r.protocol] = append([]*referencedNetworkEndpoint{r}, n.primary[r.protocol]...)
+	}
+}
+
 func (n *NIC) removeEndpointLocked(r *referencedNetworkEndpoint) {
 	id := *r.ep.ID()
 
@@ -550,9 +580,10 @@ func (n *NIC) removeEndpointLocked(r *referencedNetworkEndpoint) {
 	}
 
 	delete(n.endpoints, id)
-	for i, ref := range n.primary[r.protocol] {
+	refs := n.primary[r.protocol]
+	for i, ref := range refs {
 		if ref == r {
-			n.primary[r.protocol] = append(n.primary[r.protocol][:i], n.primary[r.protocol][i+1:]...)
+			n.primary[r.protocol] = append(refs[:i], refs[i+1:]...)
 			break
 		}
 	}