diff options
Diffstat (limited to 'pkg/tcpip/network/ipv6/icmp.go')
| -rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 51 |
1 files changed, 33 insertions, 18 deletions
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index 37c169a5d..7be35c78b 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -440,8 +440,6 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme return } - remoteLinkAddr := r.RemoteLinkAddress - // As per RFC 4291 section 2.7, multicast addresses must not be used as // source addresses in IPv6 packets. localAddr := r.LocalAddress @@ -456,9 +454,6 @@ func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragme } defer r.Release() - // Use the link address from the source of the original packet. - r.ResolveWith(remoteLinkAddr) - replyPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ ReserveHeaderBytes: int(r.MaxHeaderLength()) + header.ICMPv6EchoMinimumSize, Data: pkt.Data, @@ -742,14 +737,7 @@ func (*icmpReasonPortUnreachable) isICMPReason() {} // returnError takes an error descriptor and generates the appropriate ICMP // error packet for IPv6 and sends it. -func returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tcpip.Error { - stats := r.Stats().ICMP - sent := stats.V6PacketsSent - if !r.Stack().AllowICMPMessage() { - sent.RateLimited.Increment() - return nil - } - +func (p *protocol) returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tcpip.Error { // Only send ICMP error if the address is not a multicast v6 // address and the source is not the unspecified address. // @@ -780,6 +768,26 @@ func returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tc return nil } + // Even if we were able to receive a packet from some remote, we may not have + // a route to it - the remote may be blocked via routing rules. We must always + // consult our routing table and find a route to the remote before sending any + // packet. + route, err := p.stack.FindRoute(r.NICID(), r.LocalAddress, r.RemoteAddress, ProtocolNumber, false /* multicastLoop */) + if err != nil { + return err + } + defer route.Release() + // From this point on, the incoming route should no longer be used; route + // must be used to send the ICMP error. + r = nil + + stats := p.stack.Stats().ICMP + sent := stats.V6PacketsSent + if !p.stack.AllowICMPMessage() { + sent.RateLimited.Increment() + return nil + } + network, transport := pkt.NetworkHeader().View(), pkt.TransportHeader().View() if pkt.TransportProtocolNumber == header.ICMPv6ProtocolNumber { @@ -806,11 +814,11 @@ func returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tc // packet that caused the error) as possible without making // the error message packet exceed the minimum IPv6 MTU // [IPv6]. - mtu := int(r.MTU()) + mtu := int(route.MTU()) if mtu > header.IPv6MinimumMTU { mtu = header.IPv6MinimumMTU } - headerLen := int(r.MaxHeaderLength()) + header.ICMPv6ErrorHeaderSize + headerLen := int(route.MaxHeaderLength()) + header.ICMPv6ErrorHeaderSize available := int(mtu) - headerLen if available < header.IPv6MinimumSize { return nil @@ -843,9 +851,16 @@ func returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tc default: panic(fmt.Sprintf("unsupported ICMP type %T", reason)) } - icmpHdr.SetChecksum(header.ICMPv6Checksum(icmpHdr, r.LocalAddress, r.RemoteAddress, newPkt.Data)) - err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, newPkt) - if err != nil { + icmpHdr.SetChecksum(header.ICMPv6Checksum(icmpHdr, route.LocalAddress, route.RemoteAddress, newPkt.Data)) + if err := route.WritePacket( + nil, /* gso */ + stack.NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: route.DefaultTTL(), + TOS: stack.DefaultTOS, + }, + newPkt, + ); err != nil { sent.Dropped.Increment() return err } |