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-rw-r--r--pkg/tcpip/network/internal/ip/errors.go12
-rw-r--r--pkg/tcpip/network/internal/ip/stats.go9
-rw-r--r--pkg/tcpip/network/ipv4/icmp.go22
-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go29
-rw-r--r--pkg/tcpip/network/ipv4/ipv4_test.go208
-rw-r--r--pkg/tcpip/network/ipv6/icmp.go78
-rw-r--r--pkg/tcpip/network/ipv6/ipv6.go29
-rw-r--r--pkg/tcpip/network/ipv6/ipv6_test.go78
-rw-r--r--pkg/tcpip/stack/packet_buffer.go7
-rw-r--r--pkg/tcpip/stack/registration.go3
-rw-r--r--pkg/tcpip/tcpip.go4
11 files changed, 391 insertions, 88 deletions
diff --git a/pkg/tcpip/network/internal/ip/errors.go b/pkg/tcpip/network/internal/ip/errors.go
index d3577b377..94f1cd1cb 100644
--- a/pkg/tcpip/network/internal/ip/errors.go
+++ b/pkg/tcpip/network/internal/ip/errors.go
@@ -58,14 +58,22 @@ func (*ErrLinkLocalDestinationAddress) isForwardingError() {}
func (*ErrLinkLocalDestinationAddress) String() string { return "link local destination address" }
-// ErrNoRoute indicates the Netstack couldn't find a route for the
-// received packet.
+// ErrNoRoute indicates that a route for the received packet couldn't be found.
type ErrNoRoute struct{}
func (*ErrNoRoute) isForwardingError() {}
func (*ErrNoRoute) String() string { return "no route" }
+// ErrMessageTooLong indicates the packet was too big for the outgoing MTU.
+//
+// +stateify savable
+type ErrMessageTooLong struct{}
+
+func (*ErrMessageTooLong) isForwardingError() {}
+
+func (*ErrMessageTooLong) String() string { return "message too long" }
+
// ErrOther indicates the packet coould not be forwarded for a reason
// captured by the contained error.
type ErrOther struct {
diff --git a/pkg/tcpip/network/internal/ip/stats.go b/pkg/tcpip/network/internal/ip/stats.go
index 68b8b550e..444515d40 100644
--- a/pkg/tcpip/network/internal/ip/stats.go
+++ b/pkg/tcpip/network/internal/ip/stats.go
@@ -38,6 +38,10 @@ type MultiCounterIPForwardingStats struct {
// because they contained a link-local destination address.
LinkLocalDestination tcpip.MultiCounterStat
+ // PacketTooBig is the number of IP packets which were dropped because they
+ // were too big for the outgoing MTU.
+ PacketTooBig tcpip.MultiCounterStat
+
// ExtensionHeaderProblem is the number of IP packets which were dropped
// because of a problem encountered when processing an IPv6 extension
// header.
@@ -55,6 +59,7 @@ func (m *MultiCounterIPForwardingStats) Init(a, b *tcpip.IPForwardingStats) {
m.LinkLocalSource.Init(a.LinkLocalSource, b.LinkLocalSource)
m.LinkLocalDestination.Init(a.LinkLocalDestination, b.LinkLocalDestination)
m.ExtensionHeaderProblem.Init(a.ExtensionHeaderProblem, b.ExtensionHeaderProblem)
+ m.PacketTooBig.Init(a.PacketTooBig, b.PacketTooBig)
m.ExhaustedTTL.Init(a.ExhaustedTTL, b.ExhaustedTTL)
}
@@ -82,8 +87,8 @@ type MultiCounterIPStats struct {
// wire.
InvalidSourceAddressesReceived tcpip.MultiCounterStat
- // PacketsDelivered is the number of incoming IP packets that are
- // successfully delivered to the transport layer.
+ // PacketsDelivered is the number of incoming IP packets successfully
+ // delivered to the transport layer.
PacketsDelivered tcpip.MultiCounterStat
// PacketsSent is the number of IP packets sent via WritePacket.
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index c8ed1ce79..d1a82b584 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -387,6 +387,8 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
// icmpReason is a marker interface for IPv4 specific ICMP errors.
type icmpReason interface {
isICMPReason()
+ // isForwarding indicates whether or not the error arose while attempting to
+ // forward a packet.
isForwarding() bool
}
@@ -463,6 +465,22 @@ func (*icmpReasonNetworkUnreachable) isForwarding() bool {
return true
}
+// icmpReasonFragmentationNeeded is an error where a packet requires
+// fragmentation while also having the Don't Fragment flag set, as per RFC 792
+// page 3, Destination Unreachable Message.
+type icmpReasonFragmentationNeeded struct{}
+
+func (*icmpReasonFragmentationNeeded) isICMPReason() {}
+func (*icmpReasonFragmentationNeeded) isForwarding() bool {
+ // If we hit a Don't Fragment error, then we know we are operating as a router.
+ // As per RFC 792 page 4, Destination Unreachable Message,
+ //
+ // Another case is when a datagram must be fragmented to be forwarded by a
+ // gateway yet the Don't Fragment flag is on. In this case the gateway must
+ // discard the datagram and may return a destination unreachable message.
+ return true
+}
+
// returnError takes an error descriptor and generates the appropriate ICMP
// error packet for IPv4 and sends it back to the remote device that sent
// the problematic packet. It incorporates as much of that packet as
@@ -635,6 +653,10 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
icmpHdr.SetType(header.ICMPv4DstUnreachable)
icmpHdr.SetCode(header.ICMPv4NetUnreachable)
counter = sent.dstUnreachable
+ case *icmpReasonFragmentationNeeded:
+ icmpHdr.SetType(header.ICMPv4DstUnreachable)
+ icmpHdr.SetCode(header.ICMPv4FragmentationNeeded)
+ counter = sent.dstUnreachable
case *icmpReasonTTLExceeded:
icmpHdr.SetType(header.ICMPv4TimeExceeded)
icmpHdr.SetCode(header.ICMPv4TTLExceeded)
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index 4031032d0..aef83e834 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -434,6 +434,12 @@ func (e *endpoint) writePacket(r *stack.Route, pkt *stack.PacketBuffer, headerIn
}
if packetMustBeFragmented(pkt, networkMTU) {
+ h := header.IPv4(pkt.NetworkHeader().View())
+ if h.Flags()&header.IPv4FlagDontFragment != 0 && pkt.NetworkPacketInfo.IsForwardedPacket {
+ // TODO(gvisor.dev/issue/5919): Handle error condition in which DontFragment
+ // is set but the packet must be fragmented for the non-forwarding case.
+ return &tcpip.ErrMessageTooLong{}
+ }
sent, remain, err := e.handleFragments(r, networkMTU, pkt, func(fragPkt *stack.PacketBuffer) tcpip.Error {
// TODO(gvisor.dev/issue/3884): Evaluate whether we want to send each
// fragment one by one using WritePacket() (current strategy) or if we
@@ -695,13 +701,28 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) ip.ForwardingError {
// spent, the field must be decremented by 1.
newHdr.SetTTL(ttl - 1)
- if err := r.WriteHeaderIncludedPacket(stack.NewPacketBuffer(stack.PacketBufferOptions{
+ switch err := r.WriteHeaderIncludedPacket(stack.NewPacketBuffer(stack.PacketBufferOptions{
ReserveHeaderBytes: int(r.MaxHeaderLength()),
Data: buffer.View(newHdr).ToVectorisedView(),
- })); err != nil {
+ IsForwardedPacket: true,
+ })); err.(type) {
+ case nil:
+ return nil
+ case *tcpip.ErrMessageTooLong:
+ // As per RFC 792, page 4, Destination Unreachable:
+ //
+ // Another case is when a datagram must be fragmented to be forwarded by a
+ // gateway yet the Don't Fragment flag is on. In this case the gateway must
+ // discard the datagram and may return a destination unreachable message.
+ //
+ // WriteHeaderIncludedPacket checks for the presence of the Don't Fragment bit
+ // while sending the packet and returns this error iff fragmentation is
+ // necessary and the bit is also set.
+ _ = e.protocol.returnError(&icmpReasonFragmentationNeeded{}, pkt)
+ return &ip.ErrMessageTooLong{}
+ default:
return &ip.ErrOther{Err: err}
}
- return nil
}
// HandlePacket is called by the link layer when new ipv4 packets arrive for
@@ -830,6 +851,8 @@ func (e *endpoint) handleValidatedPacket(h header.IPv4, pkt *stack.PacketBuffer)
case *ip.ErrParameterProblem:
e.protocol.stack.Stats().MalformedRcvdPackets.Increment()
stats.ip.MalformedPacketsReceived.Increment()
+ case *ip.ErrMessageTooLong:
+ stats.ip.Forwarding.PacketTooBig.Increment()
default:
panic(fmt.Sprintf("unexpected error %s while trying to forward packet: %#v", err, pkt))
}
diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go
index 7a7cad04a..3c8a39973 100644
--- a/pkg/tcpip/network/ipv4/ipv4_test.go
+++ b/pkg/tcpip/network/ipv4/ipv4_test.go
@@ -112,6 +112,10 @@ func TestExcludeBroadcast(t *testing.T) {
})
}
+type forwardedPacket struct {
+ fragments []fragmentInfo
+}
+
func TestForwarding(t *testing.T) {
const (
nicID1 = 1
@@ -129,6 +133,7 @@ func TestForwarding(t *testing.T) {
Address: tcpip.Address(net.ParseIP("11.0.0.1").To4()),
PrefixLen: 8,
}
+ linkAddr2 := tcpip.LinkAddress("\x02\x03\x03\x04\x05\x06")
remoteIPv4Addr1 := tcpip.Address(net.ParseIP("10.0.0.2").To4())
remoteIPv4Addr2 := tcpip.Address(net.ParseIP("11.0.0.2").To4())
unreachableIPv4Addr := tcpip.Address(net.ParseIP("12.0.0.2").To4())
@@ -141,7 +146,9 @@ func TestForwarding(t *testing.T) {
sourceAddr tcpip.Address
destAddr tcpip.Address
expectErrorICMP bool
- expectPacketForwarded bool
+ ipFlags uint8
+ mtu uint32
+ payloadLength int
options header.IPv4Options
forwardedOptions header.IPv4Options
icmpType header.ICMPv4Type
@@ -149,6 +156,8 @@ func TestForwarding(t *testing.T) {
expectPacketUnrouteableError bool
expectLinkLocalSourceError bool
expectLinkLocalDestError bool
+ expectPacketForwarded bool
+ expectedFragmentsForwarded []fragmentInfo
}{
{
name: "TTL of zero",
@@ -158,6 +167,7 @@ func TestForwarding(t *testing.T) {
expectErrorICMP: true,
icmpType: header.ICMPv4TimeExceeded,
icmpCode: header.ICMPv4TTLExceeded,
+ mtu: ipv4.MaxTotalSize,
},
{
name: "TTL of one",
@@ -165,6 +175,7 @@ func TestForwarding(t *testing.T) {
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
expectPacketForwarded: true,
+ mtu: ipv4.MaxTotalSize,
},
{
name: "TTL of two",
@@ -172,6 +183,7 @@ func TestForwarding(t *testing.T) {
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
expectPacketForwarded: true,
+ mtu: ipv4.MaxTotalSize,
},
{
name: "Max TTL",
@@ -179,6 +191,7 @@ func TestForwarding(t *testing.T) {
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
expectPacketForwarded: true,
+ mtu: ipv4.MaxTotalSize,
},
{
name: "four EOL options",
@@ -186,6 +199,7 @@ func TestForwarding(t *testing.T) {
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
expectPacketForwarded: true,
+ mtu: ipv4.MaxTotalSize,
options: header.IPv4Options{0, 0, 0, 0},
forwardedOptions: header.IPv4Options{0, 0, 0, 0},
},
@@ -194,6 +208,7 @@ func TestForwarding(t *testing.T) {
TTL: 2,
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
+ mtu: ipv4.MaxTotalSize,
options: header.IPv4Options{
68, 12, 13, 0xF1,
192, 168, 1, 12,
@@ -208,6 +223,7 @@ func TestForwarding(t *testing.T) {
TTL: 2,
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
+ mtu: ipv4.MaxTotalSize,
options: header.IPv4Options{
68, 24, 21, 0x00,
1, 2, 3, 4,
@@ -231,6 +247,7 @@ func TestForwarding(t *testing.T) {
TTL: 2,
sourceAddr: remoteIPv4Addr1,
destAddr: remoteIPv4Addr2,
+ mtu: ipv4.MaxTotalSize,
options: header.IPv4Options{
68, 12, 13, 0x11,
192, 168, 1, 12,
@@ -254,6 +271,7 @@ func TestForwarding(t *testing.T) {
sourceAddr: remoteIPv4Addr1,
destAddr: unreachableIPv4Addr,
expectErrorICMP: true,
+ mtu: ipv4.MaxTotalSize,
icmpType: header.ICMPv4DstUnreachable,
icmpCode: header.ICMPv4NetUnreachable,
expectPacketUnrouteableError: true,
@@ -278,6 +296,51 @@ func TestForwarding(t *testing.T) {
destAddr: remoteIPv4Addr2,
expectLinkLocalSourceError: true,
},
+ {
+ name: "Fragmentation needed and DF set",
+ TTL: 2,
+ sourceAddr: remoteIPv4Addr1,
+ destAddr: remoteIPv4Addr2,
+ ipFlags: header.IPv4FlagDontFragment,
+ // We've picked this MTU because it is:
+ //
+ // 1) Greater than the minimum MTU that IPv4 hosts are required to process
+ // (576 bytes). As per RFC 1812, Section 4.3.2.3:
+ //
+ // The ICMP datagram SHOULD contain as much of the original datagram as
+ // possible without the length of the ICMP datagram exceeding 576 bytes.
+ //
+ // Therefore, setting an MTU greater than 576 bytes ensures that we can fit a
+ // complete ICMP packet on the incoming endpoint (and make assertions about
+ // it).
+ //
+ // 2) Less than `ipv4.MaxTotalSize`, which lets us build an IPv4 packet whose
+ // size exceeds the MTU.
+ mtu: 1000,
+ payloadLength: 1004,
+ expectErrorICMP: true,
+ icmpType: header.ICMPv4DstUnreachable,
+ icmpCode: header.ICMPv4FragmentationNeeded,
+ },
+ {
+ name: "Fragmentation needed and DF not set",
+ TTL: 2,
+ sourceAddr: remoteIPv4Addr1,
+ destAddr: remoteIPv4Addr2,
+ mtu: 1000,
+ payloadLength: 1004,
+ expectPacketForwarded: true,
+ // Combined, these fragments have length of 1012 octets, which is equal to
+ // the length of the payload (1004 octets), plus the length of the ICMP
+ // header (8 octets).
+ expectedFragmentsForwarded: []fragmentInfo{
+ // The first fragment has a length of the greatest multiple of 8 which is
+ // less than or equal to to `mtu - header.IPv4MinimumSize`.
+ {offset: 0, payloadSize: uint16(976), more: true},
+ // The next fragment holds the rest of the packet.
+ {offset: uint16(976), payloadSize: 36, more: false},
+ },
+ },
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
@@ -293,7 +356,7 @@ func TestForwarding(t *testing.T) {
clock.Advance(time.Millisecond * randomTimeOffset)
// We expect at most a single packet in response to our ICMP Echo Request.
- e1 := channel.New(1, ipv4.MaxTotalSize, "")
+ e1 := channel.New(1, test.mtu, "")
if err := s.CreateNIC(nicID1, e1); err != nil {
t.Fatalf("CreateNIC(%d, _): %s", nicID1, err)
}
@@ -302,7 +365,11 @@ func TestForwarding(t *testing.T) {
t.Fatalf("AddProtocolAddress(%d, %#v): %s", nicID1, ipv4ProtoAddr1, err)
}
- e2 := channel.New(1, ipv4.MaxTotalSize, "")
+ expectedEmittedPacketCount := 1
+ if len(test.expectedFragmentsForwarded) > expectedEmittedPacketCount {
+ expectedEmittedPacketCount = len(test.expectedFragmentsForwarded)
+ }
+ e2 := channel.New(expectedEmittedPacketCount, test.mtu, linkAddr2)
if err := s.CreateNIC(nicID2, e2); err != nil {
t.Fatalf("CreateNIC(%d, _): %s", nicID2, err)
}
@@ -330,9 +397,11 @@ func TestForwarding(t *testing.T) {
if ipHeaderLength > header.IPv4MaximumHeaderSize {
t.Fatalf("got ipHeaderLength = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize)
}
- totalLen := uint16(ipHeaderLength + header.ICMPv4MinimumSize)
- hdr := buffer.NewPrependable(int(totalLen))
- icmp := header.ICMPv4(hdr.Prepend(header.ICMPv4MinimumSize))
+ icmpHeaderLength := header.ICMPv4MinimumSize
+ totalLength := ipHeaderLength + icmpHeaderLength + test.payloadLength
+ hdr := buffer.NewPrependable(totalLength)
+ hdr.Prepend(test.payloadLength)
+ icmp := header.ICMPv4(hdr.Prepend(icmpHeaderLength))
icmp.SetIdent(randomIdent)
icmp.SetSequence(randomSequence)
icmp.SetType(header.ICMPv4Echo)
@@ -341,11 +410,12 @@ func TestForwarding(t *testing.T) {
icmp.SetChecksum(^header.Checksum(icmp, 0))
ip := header.IPv4(hdr.Prepend(ipHeaderLength))
ip.Encode(&header.IPv4Fields{
- TotalLength: totalLen,
+ TotalLength: uint16(totalLength),
Protocol: uint8(header.ICMPv4ProtocolNumber),
TTL: test.TTL,
SrcAddr: test.sourceAddr,
DstAddr: test.destAddr,
+ Flags: test.ipFlags,
})
if len(test.options) != 0 {
ip.SetHeaderLength(uint8(ipHeaderLength))
@@ -360,6 +430,7 @@ func TestForwarding(t *testing.T) {
requestPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
Data: hdr.View().ToVectorisedView(),
})
+ requestPkt.NetworkProtocolNumber = header.IPv4ProtocolNumber
e1.InjectInbound(header.IPv4ProtocolNumber, requestPkt)
reply, ok := e1.Read()
@@ -368,6 +439,18 @@ func TestForwarding(t *testing.T) {
t.Fatalf("expected ICMP packet type %d through incoming NIC", test.icmpType)
}
+ // We expect the ICMP packet to contain as much of the original packet as
+ // possible up to a limit of 576 bytes, split between payload, IP header,
+ // and ICMP header.
+ expectedICMPPayloadLength := func() int {
+ maxICMPPacketLength := header.IPv4MinimumProcessableDatagramSize
+ maxICMPPayloadLength := maxICMPPacketLength - icmpHeaderLength - ipHeaderLength
+ if len(hdr.View()) > maxICMPPayloadLength {
+ return maxICMPPayloadLength
+ }
+ return len(hdr.View())
+ }
+
checker.IPv4(t, header.IPv4(stack.PayloadSince(reply.Pkt.NetworkHeader())),
checker.SrcAddr(ipv4Addr1.Address),
checker.DstAddr(test.sourceAddr),
@@ -376,41 +459,58 @@ func TestForwarding(t *testing.T) {
checker.ICMPv4Checksum(),
checker.ICMPv4Type(test.icmpType),
checker.ICMPv4Code(test.icmpCode),
- checker.ICMPv4Payload([]byte(hdr.View())),
+ checker.ICMPv4Payload([]byte(hdr.View()[0:expectedICMPPayloadLength()])),
),
)
-
- if n := e2.Drain(); n != 0 {
- t.Fatalf("got e2.Drain() = %d, want = 0", n)
- }
} else if ok {
t.Fatalf("expected no ICMP packet through incoming NIC, instead found: %#v", reply)
}
- reply, ok = e2.Read()
if test.expectPacketForwarded {
- if !ok {
- t.Fatal("expected ICMP Echo packet through outgoing NIC")
- }
+ if len(test.expectedFragmentsForwarded) != 0 {
+ fragmentedPackets := []*stack.PacketBuffer{}
+ for i := 0; i < len(test.expectedFragmentsForwarded); i++ {
+ reply, ok = e2.Read()
+ if !ok {
+ t.Fatal("expected ICMP Echo fragment through outgoing NIC")
+ }
+ fragmentedPackets = append(fragmentedPackets, reply.Pkt)
+ }
- checker.IPv4(t, header.IPv4(stack.PayloadSince(reply.Pkt.NetworkHeader())),
- checker.SrcAddr(test.sourceAddr),
- checker.DstAddr(test.destAddr),
- checker.TTL(test.TTL-1),
- checker.IPv4Options(test.forwardedOptions),
- checker.ICMPv4(
- checker.ICMPv4Checksum(),
- checker.ICMPv4Type(header.ICMPv4Echo),
- checker.ICMPv4Code(header.ICMPv4UnusedCode),
- checker.ICMPv4Payload(nil),
- ),
- )
+ // The forwarded packet's TTL will have been decremented.
+ ipHeader := header.IPv4(requestPkt.NetworkHeader().View())
+ ipHeader.SetTTL(ipHeader.TTL() - 1)
+
+ // Forwarded packets have available header bytes equalling the sum of the
+ // maximum IP header size and the maximum size allocated for link layer
+ // headers. In this case, no size is allocated for link layer headers.
+ expectedAvailableHeaderBytes := header.IPv4MaximumHeaderSize
+ if err := compareFragments(fragmentedPackets, requestPkt, uint32(test.mtu), test.expectedFragmentsForwarded, header.ICMPv4ProtocolNumber, true /* withIPHeader */, expectedAvailableHeaderBytes); err != nil {
+ t.Error(err)
+ }
+ } else {
+ reply, ok = e2.Read()
+ if !ok {
+ t.Fatal("expected ICMP Echo packet through outgoing NIC")
+ }
- if n := e1.Drain(); n != 0 {
- t.Fatalf("got e1.Drain() = %d, want = 0", n)
+ checker.IPv4(t, header.IPv4(stack.PayloadSince(reply.Pkt.NetworkHeader())),
+ checker.SrcAddr(test.sourceAddr),
+ checker.DstAddr(test.destAddr),
+ checker.TTL(test.TTL-1),
+ checker.IPv4Options(test.forwardedOptions),
+ checker.ICMPv4(
+ checker.ICMPv4Checksum(),
+ checker.ICMPv4Type(header.ICMPv4Echo),
+ checker.ICMPv4Code(header.ICMPv4UnusedCode),
+ checker.ICMPv4Payload(nil),
+ ),
+ )
+ }
+ } else {
+ if reply, ok = e2.Read(); ok {
+ t.Fatalf("expected no ICMP Echo packet through outgoing NIC, instead found: %#v", reply)
}
- } else if ok {
- t.Fatalf("expected no ICMP Echo packet through outgoing NIC, instead found: %#v", reply)
}
boolToInt := func(val bool) uint64 {
@@ -443,6 +543,10 @@ func TestForwarding(t *testing.T) {
if got, want := s.Stats().IP.Forwarding.Errors.Value(), boolToInt(!test.expectPacketForwarded); got != want {
t.Errorf("got s.Stats().IP.Forwarding.Errors.Value() = %d, want = %d", got, want)
}
+
+ if got, want := s.Stats().IP.Forwarding.PacketTooBig.Value(), boolToInt(test.icmpCode == header.ICMPv4FragmentationNeeded); got != want {
+ t.Errorf("got s.Stats().IP.Forwarding.PacketTooBig.Value() = %d, want = %d", got, want)
+ }
})
}
}
@@ -1264,13 +1368,25 @@ func TestIPv4Sanity(t *testing.T) {
}
}
-// comparePayloads compared the contents of all the packets against the contents
-// of the source packet.
-func compareFragments(packets []*stack.PacketBuffer, sourcePacket *stack.PacketBuffer, mtu uint32, wantFragments []fragmentInfo, proto tcpip.TransportProtocolNumber) error {
+// compareFragments compares the contents of a set of fragmented packets against
+// the contents of a source packet.
+//
+// If withIPHeader is set to true, we will validate the fragmented packets' IP
+// headers against the source packet's IP header. If set to false, we validate
+// the fragmented packets' IP headers against each other.
+func compareFragments(packets []*stack.PacketBuffer, sourcePacket *stack.PacketBuffer, mtu uint32, wantFragments []fragmentInfo, proto tcpip.TransportProtocolNumber, withIPHeader bool, expectedAvailableHeaderBytes int) error {
// Make a complete array of the sourcePacket packet.
- source := header.IPv4(packets[0].NetworkHeader().View())
+ var source header.IPv4
vv := buffer.NewVectorisedView(sourcePacket.Size(), sourcePacket.Views())
- source = append(source, vv.ToView()...)
+
+ // If the packet to be fragmented contains an IPv4 header, use that header for
+ // validating fragment headers. Else, use the header of the first fragment.
+ if withIPHeader {
+ source = header.IPv4(vv.ToView())
+ } else {
+ source = header.IPv4(packets[0].NetworkHeader().View())
+ source = append(source, vv.ToView()...)
+ }
// Make a copy of the IP header, which will be modified in some fields to make
// an expected header.
@@ -1293,12 +1409,12 @@ func compareFragments(packets []*stack.PacketBuffer, sourcePacket *stack.PacketB
if got := fragmentIPHeader.TransportProtocol(); got != proto {
return fmt.Errorf("fragment #%d: got fragmentIPHeader.TransportProtocol() = %d, want = %d", i, got, uint8(proto))
}
- if got := packet.AvailableHeaderBytes(); got != extraHeaderReserve {
- return fmt.Errorf("fragment #%d: got packet.AvailableHeaderBytes() = %d, want = %d", i, got, extraHeaderReserve)
- }
if got, want := packet.NetworkProtocolNumber, sourcePacket.NetworkProtocolNumber; got != want {
return fmt.Errorf("fragment #%d: got fragment.NetworkProtocolNumber = %d, want = %d", i, got, want)
}
+ if got := packet.AvailableHeaderBytes(); got != expectedAvailableHeaderBytes {
+ return fmt.Errorf("fragment #%d: got packet.AvailableHeaderBytes() = %d, want = %d", i, got, expectedAvailableHeaderBytes)
+ }
if got, want := fragmentIPHeader.CalculateChecksum(), uint16(0xffff); got != want {
return fmt.Errorf("fragment #%d: got ip.CalculateChecksum() = %#x, want = %#x", i, got, want)
}
@@ -1314,6 +1430,14 @@ func compareFragments(packets []*stack.PacketBuffer, sourcePacket *stack.PacketB
sourceCopy.SetTotalLength(wantFragments[i].payloadSize + header.IPv4MinimumSize)
sourceCopy.SetChecksum(0)
sourceCopy.SetChecksum(^sourceCopy.CalculateChecksum())
+
+ // If we are validating against the original IP header, we should exclude the
+ // ID field, which will only be set fo fragmented packets.
+ if withIPHeader {
+ fragmentIPHeader.SetID(0)
+ fragmentIPHeader.SetChecksum(0)
+ fragmentIPHeader.SetChecksum(^fragmentIPHeader.CalculateChecksum())
+ }
if diff := cmp.Diff(fragmentIPHeader[:fragmentIPHeader.HeaderLength()], sourceCopy[:sourceCopy.HeaderLength()]); diff != "" {
return fmt.Errorf("fragment #%d: fragmentIPHeader mismatch (-want +got):\n%s", i, diff)
}
@@ -1442,7 +1566,7 @@ func TestFragmentationWritePacket(t *testing.T) {
if got := r.Stats().IP.OutgoingPacketErrors.Value(); got != 0 {
t.Errorf("got r.Stats().IP.OutgoingPacketErrors.Value() = %d, want = 0", got)
}
- if err := compareFragments(ep.WrittenPackets, source, ft.mtu, ft.wantFragments, tcp.ProtocolNumber); err != nil {
+ if err := compareFragments(ep.WrittenPackets, source, ft.mtu, ft.wantFragments, tcp.ProtocolNumber, false /* withIPHeader */, extraHeaderReserve); err != nil {
t.Error(err)
}
})
@@ -1523,7 +1647,7 @@ func TestFragmentationWritePackets(t *testing.T) {
}
fragments := ep.WrittenPackets[test.insertBefore : len(ft.wantFragments)+test.insertBefore]
- if err := compareFragments(fragments, pkt, ft.mtu, ft.wantFragments, tcp.ProtocolNumber); err != nil {
+ if err := compareFragments(fragments, pkt, ft.mtu, ft.wantFragments, tcp.ProtocolNumber, false /* withIPHeader */, extraHeaderReserve); err != nil {
t.Error(err)
}
})
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index 247a07dc2..4051fda07 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -955,7 +955,19 @@ func (*endpoint) ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bo
// icmpReason is a marker interface for IPv6 specific ICMP errors.
type icmpReason interface {
isICMPReason()
+ // isForwarding indicates whether or not the error arose while attempting to
+ // forward a packet.
isForwarding() bool
+ // respondToMulticast indicates whether this error falls under the exception
+ // outlined by RFC 4443 section 2.4 point e.3 exception 2:
+ //
+ // (e.3) A packet destined to an IPv6 multicast address. (There are two
+ // exceptions to this rule: (1) the Packet Too Big Message (Section 3.2) to
+ // allow Path MTU discovery to work for IPv6 multicast, and (2) the Parameter
+ // Problem Message, Code 2 (Section 3.4) reporting an unrecognized IPv6
+ // option (see Section 4.2 of [IPv6]) that has the Option Type highest-
+ // order two bits set to 10).
+ respondsToMulticast() bool
}
// icmpReasonParameterProblem is an error during processing of extension headers
@@ -963,18 +975,6 @@ type icmpReason interface {
type icmpReasonParameterProblem struct {
code header.ICMPv6Code
- // respondToMulticast indicates that we are sending a packet that falls under
- // the exception outlined by RFC 4443 section 2.4 point e.3 exception 2:
- //
- // (e.3) A packet destined to an IPv6 multicast address. (There are
- // two exceptions to this rule: (1) the Packet Too Big Message
- // (Section 3.2) to allow Path MTU discovery to work for IPv6
- // multicast, and (2) the Parameter Problem Message, Code 2
- // (Section 3.4) reporting an unrecognized IPv6 option (see
- // Section 4.2 of [IPv6]) that has the Option Type highest-
- // order two bits set to 10).
- respondToMulticast bool
-
// pointer is defined in the RFC 4443 setion 3.4 which reads:
//
// Pointer Identifies the octet offset within the invoking packet
@@ -985,9 +985,9 @@ type icmpReasonParameterProblem struct {
// in the maximum size of an ICMPv6 error message.
pointer uint32
- // forwarding indicates that the problem arose while we were trying to forward
- // a packet.
forwarding bool
+
+ respondToMulticast bool
}
func (*icmpReasonParameterProblem) isICMPReason() {}
@@ -995,6 +995,10 @@ func (p *icmpReasonParameterProblem) isForwarding() bool {
return p.forwarding
}
+func (p *icmpReasonParameterProblem) respondsToMulticast() bool {
+ return p.respondToMulticast
+}
+
// icmpReasonPortUnreachable is an error where the transport protocol has no
// listener and no alternative means to inform the sender.
type icmpReasonPortUnreachable struct{}
@@ -1005,6 +1009,10 @@ func (*icmpReasonPortUnreachable) isForwarding() bool {
return false
}
+func (*icmpReasonPortUnreachable) respondsToMulticast() bool {
+ return false
+}
+
// icmpReasonNetUnreachable is an error where no route can be found to the
// network of the final destination.
type icmpReasonNetUnreachable struct{}
@@ -1021,6 +1029,30 @@ func (*icmpReasonNetUnreachable) isForwarding() bool {
return true
}
+func (*icmpReasonNetUnreachable) respondsToMulticast() bool {
+ return false
+}
+
+// icmpReasonFragmentationNeeded is an error where a packet is to big to be sent
+// out through the outgoing MTU, as per RFC 4443 page 9, Packet Too Big Message.
+type icmpReasonPacketTooBig struct{}
+
+func (*icmpReasonPacketTooBig) isICMPReason() {}
+
+func (*icmpReasonPacketTooBig) isForwarding() bool {
+ // If we hit a Packet Too Big error, then we know we are operating as a router.
+ // As per RFC 4443 section 3.2:
+ //
+ // A Packet Too Big MUST be sent by a router in response to a packet that it
+ // cannot forward because the packet is larger than the MTU of the outgoing
+ // link.
+ return true
+}
+
+func (*icmpReasonPacketTooBig) respondsToMulticast() bool {
+ return true
+}
+
// icmpReasonHopLimitExceeded is an error where a packet's hop limit exceeded in
// transit to its final destination, as per RFC 4443 section 3.3.
type icmpReasonHopLimitExceeded struct{}
@@ -1039,6 +1071,10 @@ func (*icmpReasonHopLimitExceeded) isForwarding() bool {
return true
}
+func (*icmpReasonHopLimitExceeded) respondsToMulticast() bool {
+ return false
+}
+
// icmpReasonReassemblyTimeout is an error where insufficient fragments are
// received to complete reassembly of a packet within a configured time after
// the reception of the first-arriving fragment of that packet.
@@ -1050,6 +1086,10 @@ func (*icmpReasonReassemblyTimeout) isForwarding() bool {
return false
}
+func (*icmpReasonReassemblyTimeout) respondsToMulticast() bool {
+ return false
+}
+
// returnError takes an error descriptor and generates the appropriate ICMP
// error packet for IPv6 and sends it.
func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip.Error {
@@ -1078,11 +1118,7 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
// Section 4.2 of [IPv6]) that has the Option Type highest-
// order two bits set to 10).
//
- var allowResponseToMulticast bool
- if reason, ok := reason.(*icmpReasonParameterProblem); ok {
- allowResponseToMulticast = reason.respondToMulticast
- }
-
+ allowResponseToMulticast := reason.respondsToMulticast()
isOrigDstMulticast := header.IsV6MulticastAddress(origIPHdrDst)
if (!allowResponseToMulticast && isOrigDstMulticast) || origIPHdrSrc == header.IPv6Any {
return nil
@@ -1190,6 +1226,10 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
icmpHdr.SetType(header.ICMPv6DstUnreachable)
icmpHdr.SetCode(header.ICMPv6NetworkUnreachable)
counter = sent.dstUnreachable
+ case *icmpReasonPacketTooBig:
+ icmpHdr.SetType(header.ICMPv6PacketTooBig)
+ icmpHdr.SetCode(header.ICMPv6UnusedCode)
+ counter = sent.packetTooBig
case *icmpReasonHopLimitExceeded:
icmpHdr.SetType(header.ICMPv6TimeExceeded)
icmpHdr.SetCode(header.ICMPv6HopLimitExceeded)
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 029d5f51b..880290b4b 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -761,6 +761,12 @@ func (e *endpoint) writePacket(r *stack.Route, pkt *stack.PacketBuffer, protocol
}
if packetMustBeFragmented(pkt, networkMTU) {
+ if pkt.NetworkPacketInfo.IsForwardedPacket {
+ // As per RFC 2460, section 4.5:
+ // Unlike IPv4, fragmentation in IPv6 is performed only by source nodes,
+ // not by routers along a packet's delivery path.
+ return &tcpip.ErrMessageTooLong{}
+ }
sent, remain, err := e.handleFragments(r, networkMTU, pkt, protocol, func(fragPkt *stack.PacketBuffer) tcpip.Error {
// TODO(gvisor.dev/issue/3884): Evaluate whether we want to send each
// fragment one by one using WritePacket() (current strategy) or if we
@@ -950,9 +956,8 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) ip.ForwardingError {
switch err.(type) {
case nil:
case *tcpip.ErrNoRoute, *tcpip.ErrNetworkUnreachable:
- // We return the original error rather than the result of returning
- // the ICMP packet because the original error is more relevant to
- // the caller.
+ // We return the original error rather than the result of returning the
+ // ICMP packet because the original error is more relevant to the caller.
_ = e.protocol.returnError(&icmpReasonNetUnreachable{}, pkt)
return &ip.ErrNoRoute{}
default:
@@ -971,13 +976,23 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) ip.ForwardingError {
// each node that forwards the packet.
newHdr.SetHopLimit(hopLimit - 1)
- if err := r.WriteHeaderIncludedPacket(stack.NewPacketBuffer(stack.PacketBufferOptions{
+ switch err := r.WriteHeaderIncludedPacket(stack.NewPacketBuffer(stack.PacketBufferOptions{
ReserveHeaderBytes: int(r.MaxHeaderLength()),
Data: buffer.View(newHdr).ToVectorisedView(),
- })); err != nil {
+ IsForwardedPacket: true,
+ })); err.(type) {
+ case nil:
+ return nil
+ case *tcpip.ErrMessageTooLong:
+ // As per RFC 4443, section 3.2:
+ // A Packet Too Big MUST be sent by a router in response to a packet that
+ // it cannot forward because the packet is larger than the MTU of the
+ // outgoing link.
+ _ = e.protocol.returnError(&icmpReasonPacketTooBig{}, pkt)
+ return &ip.ErrMessageTooLong{}
+ default:
return &ip.ErrOther{Err: err}
}
- return nil
}
// HandlePacket is called by the link layer when new ipv6 packets arrive for
@@ -1091,6 +1106,8 @@ func (e *endpoint) handleValidatedPacket(h header.IPv6, pkt *stack.PacketBuffer)
e.stats.ip.Forwarding.Unrouteable.Increment()
case *ip.ErrParameterProblem:
e.stats.ip.Forwarding.ExtensionHeaderProblem.Increment()
+ case *ip.ErrMessageTooLong:
+ e.stats.ip.Forwarding.PacketTooBig.Increment()
default:
panic(fmt.Sprintf("unexpected error %s while trying to forward packet: %#v", err, pkt))
}
diff --git a/pkg/tcpip/network/ipv6/ipv6_test.go b/pkg/tcpip/network/ipv6/ipv6_test.go
index 8ebca735b..faf6a782e 100644
--- a/pkg/tcpip/network/ipv6/ipv6_test.go
+++ b/pkg/tcpip/network/ipv6/ipv6_test.go
@@ -3018,10 +3018,13 @@ func TestForwarding(t *testing.T) {
Address: tcpip.Address(net.ParseIP("11::1").To16()),
PrefixLen: 64,
}
+ multicastIPv6Addr := tcpip.AddressWithPrefix{
+ Address: tcpip.Address(net.ParseIP("ff00::").To16()),
+ PrefixLen: 64,
+ }
remoteIPv6Addr1 := tcpip.Address(net.ParseIP("10::2").To16())
remoteIPv6Addr2 := tcpip.Address(net.ParseIP("11::2").To16())
unreachableIPv6Addr := tcpip.Address(net.ParseIP("12::2").To16())
- multicastIPv6Addr := tcpip.Address(net.ParseIP("ff00::").To16())
linkLocalIPv6Addr := tcpip.Address(net.ParseIP("fe80::").To16())
tests := []struct {
@@ -3030,6 +3033,7 @@ func TestForwarding(t *testing.T) {
TTL uint8
expectErrorICMP bool
expectPacketForwarded bool
+ payloadLength int
countUnrouteablePackets uint64
sourceAddr tcpip.Address
destAddr tcpip.Address
@@ -3090,12 +3094,12 @@ func TestForwarding(t *testing.T) {
expectPacketUnrouteableError: true,
},
{
- name: "Multicast destination",
- TTL: 2,
- countUnrouteablePackets: 1,
- sourceAddr: remoteIPv6Addr1,
- destAddr: multicastIPv6Addr,
- expectPacketUnrouteableError: true,
+ name: "Multicast destination",
+ TTL: 2,
+ countUnrouteablePackets: 1,
+ sourceAddr: remoteIPv6Addr1,
+ destAddr: multicastIPv6Addr.Address,
+ expectPacketForwarded: true,
},
{
name: "Link local destination",
@@ -3172,7 +3176,7 @@ func TestForwarding(t *testing.T) {
name: "Hopbyhop with unknown option discard and send icmp action (multicast)",
TTL: 2,
sourceAddr: remoteIPv6Addr1,
- destAddr: multicastIPv6Addr,
+ destAddr: multicastIPv6Addr.Address,
extHdr: func(nextHdr uint8) ([]byte, uint8, checker.NetworkChecker) {
return []byte{
nextHdr, 1,
@@ -3215,7 +3219,7 @@ func TestForwarding(t *testing.T) {
name: "Hopbyhop with unknown option discard and send icmp action unless multicast dest (multicast)",
TTL: 2,
sourceAddr: remoteIPv6Addr1,
- destAddr: multicastIPv6Addr,
+ destAddr: multicastIPv6Addr.Address,
extHdr: func(nextHdr uint8) ([]byte, uint8, checker.NetworkChecker) {
return []byte{
nextHdr, 1,
@@ -3263,6 +3267,26 @@ func TestForwarding(t *testing.T) {
},
expectExtensionHeaderError: true,
},
+ {
+ name: "Can't fragment",
+ TTL: 2,
+ payloadLength: header.IPv6MinimumMTU + 1,
+ expectErrorICMP: true,
+ sourceAddr: remoteIPv6Addr1,
+ destAddr: remoteIPv6Addr2,
+ icmpType: header.ICMPv6PacketTooBig,
+ icmpCode: header.ICMPv6UnusedCode,
+ },
+ {
+ name: "Can't fragment multicast",
+ TTL: 2,
+ payloadLength: header.IPv6MinimumMTU + 1,
+ sourceAddr: remoteIPv6Addr1,
+ destAddr: multicastIPv6Addr.Address,
+ expectErrorICMP: true,
+ icmpType: header.ICMPv6PacketTooBig,
+ icmpCode: header.ICMPv6UnusedCode,
+ },
}
for _, test := range tests {
@@ -3299,6 +3323,10 @@ func TestForwarding(t *testing.T) {
Destination: ipv6Addr2.Subnet(),
NIC: nicID2,
},
+ {
+ Destination: multicastIPv6Addr.Subnet(),
+ NIC: nicID2,
+ },
})
if err := s.SetForwarding(ProtocolNumber, true); err != nil {
@@ -3315,8 +3343,13 @@ func TestForwarding(t *testing.T) {
}
extHdrLen := len(extHdrBytes)
- hdr := buffer.NewPrependable(header.IPv6MinimumSize + header.ICMPv6MinimumSize + extHdrLen)
- icmp := header.ICMPv6(hdr.Prepend(header.ICMPv6MinimumSize))
+ ipHeaderLength := header.IPv6MinimumSize
+ icmpHeaderLength := header.ICMPv6MinimumSize
+ totalLength := ipHeaderLength + icmpHeaderLength + test.payloadLength + extHdrLen
+ hdr := buffer.NewPrependable(totalLength)
+ hdr.Prepend(test.payloadLength)
+ icmp := header.ICMPv6(hdr.Prepend(icmpHeaderLength))
+
icmp.SetIdent(randomIdent)
icmp.SetSequence(randomSequence)
icmp.SetType(header.ICMPv6EchoRequest)
@@ -3328,9 +3361,9 @@ func TestForwarding(t *testing.T) {
Dst: test.destAddr,
}))
copy(hdr.Prepend(extHdrLen), extHdrBytes)
- ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize))
+ ip := header.IPv6(hdr.Prepend(ipHeaderLength))
ip.Encode(&header.IPv6Fields{
- PayloadLength: header.ICMPv6MinimumSize,
+ PayloadLength: uint16(header.ICMPv6MinimumSize + test.payloadLength),
TransportProtocol: transportProtocol,
HopLimit: test.TTL,
SrcAddr: test.sourceAddr,
@@ -3347,6 +3380,19 @@ func TestForwarding(t *testing.T) {
t.Fatalf("expected ICMP packet type %d through incoming NIC", test.icmpType)
}
+ // As per RFC 4443, page 9:
+ //
+ // The returned ICMP packet will contain as much of invoking packet
+ // as possible without the ICMPv6 packet exceeding the minimum IPv6
+ // MTU.
+ expectedICMPPayloadLength := func() int {
+ maxICMPPayloadLength := header.IPv6MinimumMTU - ipHeaderLength - icmpHeaderLength
+ if len(hdr.View()) > maxICMPPayloadLength {
+ return maxICMPPayloadLength
+ }
+ return len(hdr.View())
+ }
+
checker.IPv6(t, header.IPv6(stack.PayloadSince(reply.Pkt.NetworkHeader())),
checker.SrcAddr(ipv6Addr1.Address),
checker.DstAddr(test.sourceAddr),
@@ -3354,7 +3400,7 @@ func TestForwarding(t *testing.T) {
checker.ICMPv6(
checker.ICMPv6Type(test.icmpType),
checker.ICMPv6Code(test.icmpCode),
- checker.ICMPv6Payload([]byte(hdr.View())),
+ checker.ICMPv6Payload([]byte(hdr.View()[0:expectedICMPPayloadLength()])),
),
)
@@ -3420,6 +3466,10 @@ func TestForwarding(t *testing.T) {
if got, want := s.Stats().IP.Forwarding.ExtensionHeaderProblem.Value(), boolToInt(test.expectExtensionHeaderError); got != want {
t.Errorf("got s.Stats().IP.Forwarding.ExtensionHeaderProblem.Value() = %d, want = %d", got, want)
}
+
+ if got, want := s.Stats().IP.Forwarding.PacketTooBig.Value(), boolToInt(test.icmpType == header.ICMPv6PacketTooBig); got != want {
+ t.Errorf("got s.Stats().IP.Forwarding.PacketTooBig.Value() = %d, want = %d", got, want)
+ }
})
}
}
diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
index 9527416cf..fc3c54e34 100644
--- a/pkg/tcpip/stack/packet_buffer.go
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -40,6 +40,10 @@ type PacketBufferOptions struct {
// Data is the initial unparsed data for the new packet. If set, it will be
// owned by the new packet.
Data buffer.VectorisedView
+
+ // IsForwardedPacket identifies that the PacketBuffer being created is for a
+ // forwarded packet.
+ IsForwardedPacket bool
}
// A PacketBuffer contains all the data of a network packet.
@@ -132,6 +136,9 @@ func NewPacketBuffer(opts PacketBufferOptions) *PacketBuffer {
if opts.ReserveHeaderBytes != 0 {
pk.header = buffer.NewPrependable(opts.ReserveHeaderBytes)
}
+ if opts.IsForwardedPacket {
+ pk.NetworkPacketInfo.IsForwardedPacket = opts.IsForwardedPacket
+ }
return pk
}
diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index e26225552..a82c807b4 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -55,6 +55,9 @@ type NetworkPacketInfo struct {
// LocalAddressBroadcast is true if the packet's local address is a broadcast
// address.
LocalAddressBroadcast bool
+
+ // IsForwardedPacket is true if the packet is being forwarded.
+ IsForwardedPacket bool
}
// TransportErrorKind enumerates error types that are handled by the transport
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index f9acd4bb8..7b9c8cd4f 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -1548,6 +1548,10 @@ type IPForwardingStats struct {
// because they contained a link-local destination address.
LinkLocalDestination *StatCounter
+ // PacketTooBig is the number of IP packets which were dropped because they
+ // were too big for the outgoing MTU.
+ PacketTooBig *StatCounter
+
// ExtensionHeaderProblem is the number of IP packets which were dropped
// because of a problem encountered when processing an IPv6 extension
// header.
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 07:41:14 +0000