diff options
-rw-r--r-- | pkg/tcpip/checker/checker.go | 32 | ||||
-rw-r--r-- | pkg/tcpip/header/icmpv4.go | 3 | ||||
-rw-r--r-- | pkg/tcpip/network/fragmentation/fragmentation.go | 28 | ||||
-rw-r--r-- | pkg/tcpip/network/fragmentation/fragmentation_test.go | 104 | ||||
-rw-r--r-- | pkg/tcpip/network/fragmentation/reassembler.go | 22 | ||||
-rw-r--r-- | pkg/tcpip/network/fragmentation/reassembler_test.go | 23 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv4/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv4/icmp.go | 18 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv4/ipv4.go | 27 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv4/ipv4_test.go | 256 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 15 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/ipv6.go | 53 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/ipv6_test.go | 401 |
14 files changed, 919 insertions, 65 deletions
diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 6f81b0164..cf1145043 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -953,6 +953,38 @@ func ICMPv6Code(want header.ICMPv6Code) TransportChecker { } } +// ICMPv6TypeSpecific creates a checker that checks the ICMPv6 TypeSpecific +// field. +func ICMPv6TypeSpecific(want uint32) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmpv6, ok := h.(header.ICMPv6) + if !ok { + t.Fatalf("unexpected transport header passed to checker, got = %T, want = header.ICMPv6", h) + } + if got := icmpv6.TypeSpecific(); got != want { + t.Fatalf("unexpected ICMP TypeSpecific, got = %d, want = %d", got, want) + } + } +} + +// ICMPv6Payload creates a checker that checks the payload in an ICMPv6 packet. +func ICMPv6Payload(want []byte) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmpv6, ok := h.(header.ICMPv6) + if !ok { + t.Fatalf("unexpected transport header passed to checker, got = %T, want = header.ICMPv6", h) + } + payload := icmpv6.Payload() + if diff := cmp.Diff(want, payload); diff != "" { + t.Errorf("ICMP payload mismatch (-want +got):\n%s", diff) + } + } +} + // NDP creates a checker that checks that the packet contains a valid NDP // message for type of ty, with potentially additional checks specified by // checkers. diff --git a/pkg/tcpip/header/icmpv4.go b/pkg/tcpip/header/icmpv4.go index 504408878..0f5fb3964 100644 --- a/pkg/tcpip/header/icmpv4.go +++ b/pkg/tcpip/header/icmpv4.go @@ -99,7 +99,8 @@ const ( // ICMP codes for ICMPv4 Time Exceeded messages as defined in RFC 792. const ( - ICMPv4TTLExceeded ICMPv4Code = 0 + ICMPv4TTLExceeded ICMPv4Code = 0 + ICMPv4ReassemblyTimeout ICMPv4Code = 1 ) // ICMP codes for ICMPv4 Destination Unreachable messages as defined in RFC 792. diff --git a/pkg/tcpip/network/fragmentation/fragmentation.go b/pkg/tcpip/network/fragmentation/fragmentation.go index bb31ef61a..936601287 100644 --- a/pkg/tcpip/network/fragmentation/fragmentation.go +++ b/pkg/tcpip/network/fragmentation/fragmentation.go @@ -136,8 +136,16 @@ func NewFragmentation(blockSize uint16, highMemoryLimit, lowMemoryLimit int, rea // proto is the protocol number marked in the fragment being processed. It has // to be given here outside of the FragmentID struct because IPv6 should not use // the protocol to identify a fragment. +// +// releaseCB is a callback that will run when the fragment reassembly of a +// packet is complete or cancelled. releaseCB take a a boolean argument which is +// true iff the reassembly is cancelled due to timeout. releaseCB should be +// passed only with the first fragment of a packet. If more than one releaseCB +// are passed for the same packet, only the first releaseCB will be saved for +// the packet and the succeeding ones will be dropped by running them +// immediately with a false argument. func (f *Fragmentation) Process( - id FragmentID, first, last uint16, more bool, proto uint8, vv buffer.VectorisedView) ( + id FragmentID, first, last uint16, more bool, proto uint8, vv buffer.VectorisedView, releaseCB func(bool)) ( buffer.VectorisedView, uint8, bool, error) { if first > last { return buffer.VectorisedView{}, 0, false, fmt.Errorf("first=%d is greater than last=%d: %w", first, last, ErrInvalidArgs) @@ -171,6 +179,12 @@ func (f *Fragmentation) Process( f.releaseReassemblersLocked() } } + if releaseCB != nil { + if !r.setCallback(releaseCB) { + // We got a duplicate callback. Release it immediately. + releaseCB(false /* timedOut */) + } + } f.mu.Unlock() res, firstFragmentProto, done, consumed, err := r.process(first, last, more, proto, vv) @@ -178,14 +192,14 @@ func (f *Fragmentation) Process( // We probably got an invalid sequence of fragments. Just // discard the reassembler and move on. f.mu.Lock() - f.release(r) + f.release(r, false /* timedOut */) f.mu.Unlock() return buffer.VectorisedView{}, 0, false, fmt.Errorf("fragmentation processing error: %w", err) } f.mu.Lock() f.size += consumed if done { - f.release(r) + f.release(r, false /* timedOut */) } // Evict reassemblers if we are consuming more memory than highLimit until // we reach lowLimit. @@ -195,14 +209,14 @@ func (f *Fragmentation) Process( if tail == nil { break } - f.release(tail) + f.release(tail, false /* timedOut */) } } f.mu.Unlock() return res, firstFragmentProto, done, nil } -func (f *Fragmentation) release(r *reassembler) { +func (f *Fragmentation) release(r *reassembler, timedOut bool) { // Before releasing a fragment we need to check if r is already marked as done. // Otherwise, we would delete it twice. if r.checkDoneOrMark() { @@ -216,6 +230,8 @@ func (f *Fragmentation) release(r *reassembler) { log.Printf("memory counter < 0 (%d), this is an accounting bug that requires investigation", f.size) f.size = 0 } + + r.release(timedOut) // releaseCB may run. } // releaseReassemblersLocked releases already-expired reassemblers, then @@ -238,7 +254,7 @@ func (f *Fragmentation) releaseReassemblersLocked() { break } // If the oldest reassembler has already expired, release it. - f.release(r) + f.release(r, true /* timedOut*/) } } diff --git a/pkg/tcpip/network/fragmentation/fragmentation_test.go b/pkg/tcpip/network/fragmentation/fragmentation_test.go index a1eb1e243..5dcd10730 100644 --- a/pkg/tcpip/network/fragmentation/fragmentation_test.go +++ b/pkg/tcpip/network/fragmentation/fragmentation_test.go @@ -105,7 +105,7 @@ func TestFragmentationProcess(t *testing.T) { f := NewFragmentation(minBlockSize, 1024, 512, reassembleTimeout, &faketime.NullClock{}) firstFragmentProto := c.in[0].proto for i, in := range c.in { - vv, proto, done, err := f.Process(in.id, in.first, in.last, in.more, in.proto, in.vv) + vv, proto, done, err := f.Process(in.id, in.first, in.last, in.more, in.proto, in.vv, nil) if err != nil { t.Fatalf("f.Process(%+v, %d, %d, %t, %d, %X) failed: %s", in.id, in.first, in.last, in.more, in.proto, in.vv.ToView(), err) @@ -240,7 +240,7 @@ func TestReassemblingTimeout(t *testing.T) { for _, event := range test.events { clock.Advance(event.clockAdvance) if frag := event.fragment; frag != nil { - _, _, done, err := f.Process(FragmentID{}, frag.first, frag.last, frag.more, protocol, vv(len(frag.data), frag.data)) + _, _, done, err := f.Process(FragmentID{}, frag.first, frag.last, frag.more, protocol, vv(len(frag.data), frag.data), nil) if err != nil { t.Fatalf("%s: f.Process failed: %s", event.name, err) } @@ -259,15 +259,15 @@ func TestReassemblingTimeout(t *testing.T) { func TestMemoryLimits(t *testing.T) { f := NewFragmentation(minBlockSize, 3, 1, reassembleTimeout, &faketime.NullClock{}) // Send first fragment with id = 0. - f.Process(FragmentID{ID: 0}, 0, 0, true, 0xFF, vv(1, "0")) + f.Process(FragmentID{ID: 0}, 0, 0, true, 0xFF, vv(1, "0"), nil) // Send first fragment with id = 1. - f.Process(FragmentID{ID: 1}, 0, 0, true, 0xFF, vv(1, "1")) + f.Process(FragmentID{ID: 1}, 0, 0, true, 0xFF, vv(1, "1"), nil) // Send first fragment with id = 2. - f.Process(FragmentID{ID: 2}, 0, 0, true, 0xFF, vv(1, "2")) + f.Process(FragmentID{ID: 2}, 0, 0, true, 0xFF, vv(1, "2"), nil) // Send first fragment with id = 3. This should caused id = 0 and id = 1 to be // evicted. - f.Process(FragmentID{ID: 3}, 0, 0, true, 0xFF, vv(1, "3")) + f.Process(FragmentID{ID: 3}, 0, 0, true, 0xFF, vv(1, "3"), nil) if _, ok := f.reassemblers[FragmentID{ID: 0}]; ok { t.Errorf("Memory limits are not respected: id=0 has not been evicted.") @@ -283,9 +283,9 @@ func TestMemoryLimits(t *testing.T) { func TestMemoryLimitsIgnoresDuplicates(t *testing.T) { f := NewFragmentation(minBlockSize, 1, 0, reassembleTimeout, &faketime.NullClock{}) // Send first fragment with id = 0. - f.Process(FragmentID{}, 0, 0, true, 0xFF, vv(1, "0")) + f.Process(FragmentID{}, 0, 0, true, 0xFF, vv(1, "0"), nil) // Send the same packet again. - f.Process(FragmentID{}, 0, 0, true, 0xFF, vv(1, "0")) + f.Process(FragmentID{}, 0, 0, true, 0xFF, vv(1, "0"), nil) got := f.size want := 1 @@ -377,7 +377,7 @@ func TestErrors(t *testing.T) { for _, test := range tests { t.Run(test.name, func(t *testing.T) { f := NewFragmentation(test.blockSize, HighFragThreshold, LowFragThreshold, reassembleTimeout, &faketime.NullClock{}) - _, _, done, err := f.Process(FragmentID{}, test.first, test.last, test.more, 0, vv(len(test.data), test.data)) + _, _, done, err := f.Process(FragmentID{}, test.first, test.last, test.more, 0, vv(len(test.data), test.data), nil) if !errors.Is(err, test.err) { t.Errorf("got Process(_, %d, %d, %t, _, %q) = (_, _, _, %v), want = (_, _, _, %v)", test.first, test.last, test.more, test.data, err, test.err) } @@ -497,3 +497,89 @@ func TestPacketFragmenter(t *testing.T) { }) } } + +func TestReleaseCallback(t *testing.T) { + const ( + proto = 99 + ) + + var result int + var callbackReasonIsTimeout bool + cb1 := func(timedOut bool) { result = 1; callbackReasonIsTimeout = timedOut } + cb2 := func(timedOut bool) { result = 2; callbackReasonIsTimeout = timedOut } + + tests := []struct { + name string + callbacks []func(bool) + timeout bool + wantResult int + wantCallbackReasonIsTimeout bool + }{ + { + name: "callback runs on release", + callbacks: []func(bool){cb1}, + timeout: false, + wantResult: 1, + wantCallbackReasonIsTimeout: false, + }, + { + name: "first callback is nil", + callbacks: []func(bool){nil, cb2}, + timeout: false, + wantResult: 2, + wantCallbackReasonIsTimeout: false, + }, + { + name: "two callbacks - first one is set", + callbacks: []func(bool){cb1, cb2}, + timeout: false, + wantResult: 1, + wantCallbackReasonIsTimeout: false, + }, + { + name: "callback runs on timeout", + callbacks: []func(bool){cb1}, + timeout: true, + wantResult: 1, + wantCallbackReasonIsTimeout: true, + }, + { + name: "no callbacks", + callbacks: []func(bool){nil}, + timeout: false, + wantResult: 0, + wantCallbackReasonIsTimeout: false, + }, + } + + id := FragmentID{ID: 0} + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + result = 0 + callbackReasonIsTimeout = false + + f := NewFragmentation(minBlockSize, HighFragThreshold, LowFragThreshold, reassembleTimeout, &faketime.NullClock{}) + + for i, cb := range test.callbacks { + _, _, _, err := f.Process(id, uint16(i), uint16(i), true, proto, vv(1, "0"), cb) + if err != nil { + t.Errorf("f.Process error = %s", err) + } + } + + r, ok := f.reassemblers[id] + if !ok { + t.Fatalf("Reassemberr not found") + } + f.release(r, test.timeout) + + if result != test.wantResult { + t.Errorf("got result = %d, want = %d", result, test.wantResult) + } + if callbackReasonIsTimeout != test.wantCallbackReasonIsTimeout { + t.Errorf("got callbackReasonIsTimeout = %t, want = %t", callbackReasonIsTimeout, test.wantCallbackReasonIsTimeout) + } + }) + } +} diff --git a/pkg/tcpip/network/fragmentation/reassembler.go b/pkg/tcpip/network/fragmentation/reassembler.go index 9bb051a30..c0cc0bde0 100644 --- a/pkg/tcpip/network/fragmentation/reassembler.go +++ b/pkg/tcpip/network/fragmentation/reassembler.go @@ -41,6 +41,7 @@ type reassembler struct { heap fragHeap done bool creationTime int64 + callback func(bool) } func newReassembler(id FragmentID, clock tcpip.Clock) *reassembler { @@ -123,3 +124,24 @@ func (r *reassembler) checkDoneOrMark() bool { r.mu.Unlock() return prev } + +func (r *reassembler) setCallback(c func(bool)) bool { + r.mu.Lock() + defer r.mu.Unlock() + if r.callback != nil { + return false + } + r.callback = c + return true +} + +func (r *reassembler) release(timedOut bool) { + r.mu.Lock() + callback := r.callback + r.callback = nil + r.mu.Unlock() + + if callback != nil { + callback(timedOut) + } +} diff --git a/pkg/tcpip/network/fragmentation/reassembler_test.go b/pkg/tcpip/network/fragmentation/reassembler_test.go index a0a04a027..fa2a70dc8 100644 --- a/pkg/tcpip/network/fragmentation/reassembler_test.go +++ b/pkg/tcpip/network/fragmentation/reassembler_test.go @@ -105,3 +105,26 @@ func TestUpdateHoles(t *testing.T) { } } } + +func TestSetCallback(t *testing.T) { + result := 0 + reasonTimeout := false + + cb1 := func(timedOut bool) { result = 1; reasonTimeout = timedOut } + cb2 := func(timedOut bool) { result = 2; reasonTimeout = timedOut } + + r := newReassembler(FragmentID{}, &faketime.NullClock{}) + if !r.setCallback(cb1) { + t.Errorf("setCallback failed") + } + if r.setCallback(cb2) { + t.Errorf("setCallback should fail if one is already set") + } + r.release(true) + if result != 1 { + t.Errorf("got result = %d, want = 1", result) + } + if !reasonTimeout { + t.Errorf("got reasonTimeout = %t, want = true", reasonTimeout) + } +} diff --git a/pkg/tcpip/network/ipv4/BUILD b/pkg/tcpip/network/ipv4/BUILD index 7fc12e229..6252614ec 100644 --- a/pkg/tcpip/network/ipv4/BUILD +++ b/pkg/tcpip/network/ipv4/BUILD @@ -29,6 +29,7 @@ go_test( "//pkg/tcpip", "//pkg/tcpip/buffer", "//pkg/tcpip/checker", + "//pkg/tcpip/faketime", "//pkg/tcpip/header", "//pkg/tcpip/link/channel", "//pkg/tcpip/link/sniffer", diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index ac66403fa..1edb6de6b 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -237,6 +237,13 @@ type icmpReasonProtoUnreachable struct{} func (*icmpReasonProtoUnreachable) isICMPReason() {} +// 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. +type icmpReasonReassemblyTimeout struct{} + +func (*icmpReasonReassemblyTimeout) isICMPReason() {} + // 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 @@ -377,17 +384,24 @@ func (p *protocol) returnError(r *stack.Route, reason icmpReason, pkt *stack.Pac icmpPkt.TransportProtocolNumber = header.ICMPv4ProtocolNumber icmpHdr := header.ICMPv4(icmpPkt.TransportHeader().Push(header.ICMPv4MinimumSize)) + var counter *tcpip.StatCounter switch reason.(type) { case *icmpReasonPortUnreachable: + icmpHdr.SetType(header.ICMPv4DstUnreachable) icmpHdr.SetCode(header.ICMPv4PortUnreachable) + counter = sent.DstUnreachable case *icmpReasonProtoUnreachable: + icmpHdr.SetType(header.ICMPv4DstUnreachable) icmpHdr.SetCode(header.ICMPv4ProtoUnreachable) + counter = sent.DstUnreachable + case *icmpReasonReassemblyTimeout: + icmpHdr.SetType(header.ICMPv4TimeExceeded) + icmpHdr.SetCode(header.ICMPv4ReassemblyTimeout) + counter = sent.TimeExceeded default: panic(fmt.Sprintf("unsupported ICMP type %T", reason)) } - icmpHdr.SetType(header.ICMPv4DstUnreachable) icmpHdr.SetChecksum(header.ICMPv4Checksum(icmpHdr, icmpPkt.Data)) - counter := sent.DstUnreachable if err := route.WritePacket( nil, /* gso */ diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 41e548c85..e6b842d61 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -38,7 +38,7 @@ const ( // Considering that it is an old recommendation, we use the same reassembly // timeout that linux defines, which is 30 seconds: // https://github.com/torvalds/linux/blob/47ec5303d73ea344e84f46660fff693c57641386/include/net/ip.h#L138 - reassembleTimeout = 30 * time.Second + ReassembleTimeout = 30 * time.Second // ProtocolNumber is the ipv4 protocol number. ProtocolNumber = header.IPv4ProtocolNumber @@ -520,6 +520,28 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { r.Stats().IP.MalformedFragmentsReceived.Increment() return } + + // Set up a callback in case we need to send a Time Exceeded Message, as per + // RFC 792: + // + // If a host reassembling a fragmented datagram cannot complete the + // reassembly due to missing fragments within its time limit it discards + // the datagram, and it may send a time exceeded message. + // + // If fragment zero is not available then no time exceeded need be sent at + // all. + var releaseCB func(bool) + if start == 0 { + pkt := pkt.Clone() + r := r.Clone() + releaseCB = func(timedOut bool) { + if timedOut { + _ = e.protocol.returnError(&r, &icmpReasonReassemblyTimeout{}, pkt) + } + r.Release() + } + } + var ready bool var err error proto := h.Protocol() @@ -537,6 +559,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { h.More(), proto, pkt.Data, + releaseCB, ) if err != nil { r.Stats().IP.MalformedPacketsReceived.Increment() @@ -856,7 +879,7 @@ func NewProtocol(s *stack.Stack) stack.NetworkProtocol { ids: ids, hashIV: hashIV, defaultTTL: DefaultTTL, - fragmentation: fragmentation.NewFragmentation(fragmentblockSize, fragmentation.HighFragThreshold, fragmentation.LowFragThreshold, reassembleTimeout, s.Clock()), + fragmentation: fragmentation.NewFragmentation(fragmentblockSize, fragmentation.HighFragThreshold, fragmentation.LowFragThreshold, ReassembleTimeout, s.Clock()), } } diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go index 19a8f999b..dbe0935be 100644 --- a/pkg/tcpip/network/ipv4/ipv4_test.go +++ b/pkg/tcpip/network/ipv4/ipv4_test.go @@ -26,6 +26,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/checker" + "gvisor.dev/gvisor/pkg/tcpip/faketime" "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/link/channel" "gvisor.dev/gvisor/pkg/tcpip/link/sniffer" @@ -788,7 +789,6 @@ func TestInvalidFragments(t *testing.T) { autoChecksum bool // if true, the Checksum field will be overwritten. } - // These packets have both IHL and TotalLength set to 0. tests := []struct { name string fragments []fragmentData @@ -1028,7 +1028,6 @@ func TestInvalidFragments(t *testing.T) { for _, test := range tests { t.Run(test.name, func(t *testing.T) { - s := stack.New(stack.Options{ NetworkProtocols: []stack.NetworkProtocolFactory{ ipv4.NewProtocol, @@ -1071,6 +1070,259 @@ func TestInvalidFragments(t *testing.T) { } } +func TestFragmentReassemblyTimeout(t *testing.T) { + const ( + nicID = 1 + linkAddr = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0e") + addr1 = "\x0a\x00\x00\x01" + addr2 = "\x0a\x00\x00\x02" + tos = 0 + ident = 1 + ttl = 48 + protocol = 99 + data = "TEST_FRAGMENT_REASSEMBLY_TIMEOUT" + ) + + type fragmentData struct { + ipv4fields header.IPv4Fields + payload []byte + } + + tests := []struct { + name string + fragments []fragmentData + expectICMP bool + }{ + { + name: "first fragment only", + fragments: []fragmentData{ + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: header.IPv4MinimumSize + 16, + ID: ident, + Flags: header.IPv4FlagMoreFragments, + FragmentOffset: 0, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[:16], + }, + }, + expectICMP: true, + }, + { + name: "two first fragments", + fragments: []fragmentData{ + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: header.IPv4MinimumSize + 16, + ID: ident, + Flags: header.IPv4FlagMoreFragments, + FragmentOffset: 0, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[:16], + }, + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: header.IPv4MinimumSize + 16, + ID: ident, + Flags: header.IPv4FlagMoreFragments, + FragmentOffset: 0, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[:16], + }, + }, + expectICMP: true, + }, + { + name: "second fragment only", + fragments: []fragmentData{ + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: uint16(header.IPv4MinimumSize + len(data) - 16), + ID: ident, + Flags: 0, + FragmentOffset: 8, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[16:], + }, + }, + expectICMP: false, + }, + { + name: "two fragments with a gap", + fragments: []fragmentData{ + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: header.IPv4MinimumSize + 8, + ID: ident, + Flags: header.IPv4FlagMoreFragments, + FragmentOffset: 0, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[:8], + }, + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: uint16(header.IPv4MinimumSize + len(data) - 16), + ID: ident, + Flags: 0, + FragmentOffset: 16, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[16:], + }, + }, + expectICMP: true, + }, + { + name: "two fragments with a gap in reverse order", + fragments: []fragmentData{ + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: uint16(header.IPv4MinimumSize + len(data) - 16), + ID: ident, + Flags: 0, + FragmentOffset: 16, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[16:], + }, + { + ipv4fields: header.IPv4Fields{ + IHL: header.IPv4MinimumSize, + TOS: tos, + TotalLength: header.IPv4MinimumSize + 8, + ID: ident, + Flags: header.IPv4FlagMoreFragments, + FragmentOffset: 0, + TTL: ttl, + Protocol: protocol, + SrcAddr: addr1, + DstAddr: addr2, + }, + payload: []byte(data)[:8], + }, + }, + expectICMP: true, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + clock := faketime.NewManualClock() + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocolFactory{ + ipv4.NewProtocol, + }, + Clock: clock, + }) + e := channel.New(1, 1500, linkAddr) + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) + } + if err := s.AddAddress(nicID, ipv4.ProtocolNumber, addr2); err != nil { + t.Fatalf("AddAddress(%d, %d, %s) = %s", nicID, header.IPv4ProtocolNumber, addr2, err) + } + s.SetRouteTable([]tcpip.Route{{ + Destination: header.IPv4EmptySubnet, + NIC: nicID, + }}) + + var firstFragmentSent buffer.View + for _, f := range test.fragments { + pktSize := header.IPv4MinimumSize + hdr := buffer.NewPrependable(pktSize) + + ip := header.IPv4(hdr.Prepend(pktSize)) + ip.Encode(&f.ipv4fields) + + ip.SetChecksum(0) + ip.SetChecksum(^ip.CalculateChecksum()) + + vv := hdr.View().ToVectorisedView() + vv.AppendView(f.payload) + + pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ + Data: vv, + }) + + if firstFragmentSent == nil && ip.FragmentOffset() == 0 { + firstFragmentSent = stack.PayloadSince(pkt.NetworkHeader()) + } + + e.InjectInbound(header.IPv4ProtocolNumber, pkt) + } + + clock.Advance(ipv4.ReassembleTimeout) + + reply, ok := e.Read() + if !test.expectICMP { + if ok { + t.Fatalf("unexpected ICMP error message received: %#v", reply) + } + return + } + if !ok { + t.Fatal("expected ICMP error message missing") + } + if firstFragmentSent == nil { + t.Fatalf("unexpected ICMP error message received: %#v", reply) + } + + checker.IPv4(t, stack.PayloadSince(reply.Pkt.NetworkHeader()), + checker.SrcAddr(addr2), + checker.DstAddr(addr1), + checker.IPFullLength(uint16(header.IPv4MinimumSize+header.ICMPv4MinimumSize+firstFragmentSent.Size())), + checker.IPv4HeaderLength(header.IPv4MinimumSize), + checker.ICMPv4( + checker.ICMPv4Type(header.ICMPv4TimeExceeded), + checker.ICMPv4Code(header.ICMPv4ReassemblyTimeout), + checker.ICMPv4Checksum(), + checker.ICMPv4Payload([]byte(firstFragmentSent)), + ), + ) + }) + } +} + // TestReceiveFragments feeds fragments in through the incoming packet path to // test reassembly func TestReceiveFragments(t *testing.T) { diff --git a/pkg/tcpip/network/ipv6/BUILD b/pkg/tcpip/network/ipv6/BUILD index a30437f02..0ac24a6fb 100644 --- a/pkg/tcpip/network/ipv6/BUILD +++ b/pkg/tcpip/network/ipv6/BUILD @@ -36,6 +36,7 @@ go_test( "//pkg/tcpip", "//pkg/tcpip/buffer", "//pkg/tcpip/checker", + "//pkg/tcpip/faketime", "//pkg/tcpip/header", "//pkg/tcpip/link/channel", "//pkg/tcpip/link/sniffer", diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index b10249c9e..3c15e41a7 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -744,6 +744,13 @@ type icmpReasonPortUnreachable struct{} func (*icmpReasonPortUnreachable) isICMPReason() {} +// 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. +type icmpReasonReassemblyTimeout struct{} + +func (*icmpReasonReassemblyTimeout) isICMPReason() {} + // returnError takes an error descriptor and generates the appropriate ICMP // error packet for IPv6 and sends it. func (p *protocol) returnError(r *stack.Route, reason icmpReason, pkt *stack.PacketBuffer) *tcpip.Error { @@ -836,7 +843,9 @@ func (p *protocol) returnError(r *stack.Route, reason icmpReason, pkt *stack.Pac if payloadLen > available { payloadLen = available } - payload := buffer.NewVectorisedView(pkt.Size(), pkt.Views()) + payload := network.ToVectorisedView() + payload.AppendView(transport) + payload.Append(pkt.Data) payload.CapLength(payloadLen) newPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ @@ -857,6 +866,10 @@ func (p *protocol) returnError(r *stack.Route, reason icmpReason, pkt *stack.Pac icmpHdr.SetType(header.ICMPv6DstUnreachable) icmpHdr.SetCode(header.ICMPv6PortUnreachable) counter = sent.DstUnreachable + case *icmpReasonReassemblyTimeout: + icmpHdr.SetType(header.ICMPv6TimeExceeded) + icmpHdr.SetCode(header.ICMPv6ReassemblyTimeout) + counter = sent.TimeExceeded default: panic(fmt.Sprintf("unsupported ICMP type %T", reason)) } diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go index 3c2578343..1e38f3a9d 100644 --- a/pkg/tcpip/network/ipv6/ipv6.go +++ b/pkg/tcpip/network/ipv6/ipv6.go @@ -41,7 +41,7 @@ const ( // // Linux also uses 60 seconds for reassembly timeout: // https://github.com/torvalds/linux/blob/47ec5303d73ea344e84f46660fff693c57641386/include/net/ipv6.h#L456 - reassembleTimeout = 60 * time.Second + ReassembleTimeout = 60 * time.Second // ProtocolNumber is the ipv6 protocol number. ProtocolNumber = header.IPv6ProtocolNumber @@ -777,6 +777,8 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { continue } + fragmentFieldOffset := it.ParseOffset() + // Don't consume the iterator if we have the first fragment because we // will use it to validate that the first fragment holds the upper layer // header. @@ -834,17 +836,59 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { return } + // As per RFC 2460 Section 4.5: + // + // If the length of a fragment, as derived from the fragment packet's + // Payload Length field, is not a multiple of 8 octets and the M flag + // of that fragment is 1, then that fragment must be discarded and an + // ICMP Parameter Problem, Code 0, message should be sent to the source + // of the fragment, pointing to the Payload Length field of the + // fragment packet. + if extHdr.More() && fragmentPayloadLen%header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit != 0 { + r.Stats().IP.MalformedPacketsReceived.Increment() + r.Stats().IP.MalformedFragmentsReceived.Increment() + _ = e.protocol.returnError(r, &icmpReasonParameterProblem{ + code: header.ICMPv6ErroneousHeader, + pointer: header.IPv6PayloadLenOffset, + }, pkt) + return + } + // The packet is a fragment, let's try to reassemble it. start := extHdr.FragmentOffset() * header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit - // Drop the fragment if the size of the reassembled payload would exceed - // the maximum payload size. + // As per RFC 2460 Section 4.5: + // + // If the length and offset of a fragment are such that the Payload + // Length of the packet reassembled from that fragment would exceed + // 65,535 octets, then that fragment must be discarded and an ICMP + // Parameter Problem, Code 0, message should be sent to the source of + // the fragment, pointing to the Fragment Offset field of the fragment + // packet. if int(start)+fragmentPayloadLen > header.IPv6MaximumPayloadSize { r.Stats().IP.MalformedPacketsReceived.Increment() r.Stats().IP.MalformedFragmentsReceived.Increment() + _ = e.protocol.returnError(r, &icmpReasonParameterProblem{ + code: header.ICMPv6ErroneousHeader, + pointer: fragmentFieldOffset, + }, pkt) return } + // Set up a callback in case we need to send a Time Exceeded Message as + // per RFC 2460 Section 4.5. + var releaseCB func(bool) + if start == 0 { + pkt := pkt.Clone() + r := r.Clone() + releaseCB = func(timedOut bool) { + if timedOut { + _ = e.protocol.returnError(&r, &icmpReasonReassemblyTimeout{}, pkt) + } + r.Release() + } + } + // Note that pkt doesn't have its transport header set after reassembly, // and won't until DeliverNetworkPacket sets it. data, proto, ready, err := e.protocol.fragmentation.Process( @@ -860,6 +904,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { extHdr.More(), uint8(rawPayload.Identifier), rawPayload.Buf, + releaseCB, ) if err != nil { r.Stats().IP.MalformedPacketsReceived.Increment() @@ -1535,7 +1580,7 @@ func NewProtocolWithOptions(opts Options) stack.NetworkProtocolFactory { return func(s *stack.Stack) stack.NetworkProtocol { p := &protocol{ stack: s, - fragmentation: fragmentation.NewFragmentation(header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit, fragmentation.HighFragThreshold, fragmentation.LowFragThreshold, reassembleTimeout, s.Clock()), + fragmentation: fragmentation.NewFragmentation(header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit, fragmentation.HighFragThreshold, fragmentation.LowFragThreshold, ReassembleTimeout, s.Clock()), ids: ids, hashIV: hashIV, diff --git a/pkg/tcpip/network/ipv6/ipv6_test.go b/pkg/tcpip/network/ipv6/ipv6_test.go index dc4200b8a..c593c0004 100644 --- a/pkg/tcpip/network/ipv6/ipv6_test.go +++ b/pkg/tcpip/network/ipv6/ipv6_test.go @@ -24,6 +24,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/checker" + "gvisor.dev/gvisor/pkg/tcpip/faketime" "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/link/channel" "gvisor.dev/gvisor/pkg/tcpip/network/testutil" @@ -1912,16 +1913,19 @@ func TestReceiveIPv6Fragments(t *testing.T) { func TestInvalidIPv6Fragments(t *testing.T) { const ( - nicID = 1 - fragmentExtHdrLen = 8 + addr1 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" + addr2 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02" + linkAddr1 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0e") + nicID = 1 + hoplimit = 255 + ident = 1 + data = "TEST_INVALID_IPV6_FRAGMENTS" ) - payloadGen := func(payloadLen int) []byte { - payload := make([]byte, payloadLen) - for i := 0; i < len(payload); i++ { - payload[i] = 0x30 - } - return payload + type fragmentData struct { + ipv6Fields header.IPv6Fields + ipv6FragmentFields header.IPv6FragmentFields + payload []byte } tests := []struct { @@ -1929,31 +1933,64 @@ func TestInvalidIPv6Fragments(t *testing.T) { fragments []fragmentData wantMalformedIPPackets uint64 wantMalformedFragments uint64 + expectICMP bool + expectICMPType header.ICMPv6Type + expectICMPCode header.ICMPv6Code + expectICMPTypeSpecific uint32 }{ { + name: "fragment size is not a multiple of 8 and the M flag is true", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 9, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0 >> 3, + M: true, + Identification: ident, + }, + payload: []byte(data)[:9], + }, + }, + wantMalformedIPPackets: 1, + wantMalformedFragments: 1, + expectICMP: true, + expectICMPType: header.ICMPv6ParamProblem, + expectICMPCode: header.ICMPv6ErroneousHeader, + expectICMPTypeSpecific: header.IPv6PayloadLenOffset, + }, + { name: "fragments reassembled into a payload exceeding the max IPv6 payload size", fragments: []fragmentData{ { - srcAddr: addr1, - dstAddr: addr2, - nextHdr: fragmentExtHdrID, - data: buffer.NewVectorisedView( - fragmentExtHdrLen+(header.IPv6MaximumPayloadSize+1)-16, - []buffer.View{ - // Fragment extension header. - // Fragment offset = 8190, More = false, ID = 1 - buffer.View([]byte{uint8(header.UDPProtocolNumber), 0, - ((header.IPv6MaximumPayloadSize + 1) - 16) >> 8, - ((header.IPv6MaximumPayloadSize + 1) - 16) & math.MaxUint8, - 0, 0, 0, 1}), - // Payload length = 16 - payloadGen(16), - }, - ), + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: ((header.IPv6MaximumPayloadSize + 1) - 16) >> 3, + M: false, + Identification: ident, + }, + payload: []byte(data)[:16], }, }, wantMalformedIPPackets: 1, wantMalformedFragments: 1, + expectICMP: true, + expectICMPType: header.ICMPv6ParamProblem, + expectICMPCode: header.ICMPv6ErroneousHeader, + expectICMPTypeSpecific: header.IPv6MinimumSize + 2, /* offset for 'Fragment Offset' in the fragment header */ }, } @@ -1964,33 +2001,40 @@ func TestInvalidIPv6Fragments(t *testing.T) { NewProtocol, }, }) - e := channel.New(0, 1500, linkAddr1) + e := channel.New(1, 1500, linkAddr1) if err := s.CreateNIC(nicID, e); err != nil { t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) } if err := s.AddAddress(nicID, ProtocolNumber, addr2); err != nil { t.Fatalf("AddAddress(%d, %d, %s) = %s", nicID, ProtocolNumber, addr2, err) } + s.SetRouteTable([]tcpip.Route{{ + Destination: header.IPv6EmptySubnet, + NIC: nicID, + }}) + var expectICMPPayload buffer.View for _, f := range test.fragments { - hdr := buffer.NewPrependable(header.IPv6MinimumSize) + hdr := buffer.NewPrependable(header.IPv6MinimumSize + header.IPv6FragmentHeaderSize) - // Serialize IPv6 fixed header. - ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) - ip.Encode(&header.IPv6Fields{ - PayloadLength: uint16(f.data.Size()), - NextHeader: f.nextHdr, - HopLimit: 255, - SrcAddr: f.srcAddr, - DstAddr: f.dstAddr, - }) + ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize + header.IPv6FragmentHeaderSize)) + ip.Encode(&f.ipv6Fields) + + fragHDR := header.IPv6Fragment(hdr.View()[header.IPv6MinimumSize:]) + fragHDR.Encode(&f.ipv6FragmentFields) vv := hdr.View().ToVectorisedView() - vv.Append(f.data) + vv.AppendView(f.payload) - e.InjectInbound(ProtocolNumber, stack.NewPacketBuffer(stack.PacketBufferOptions{ + pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ Data: vv, - })) + }) + + if test.expectICMP { + expectICMPPayload = stack.PayloadSince(pkt.NetworkHeader()) + } + + e.InjectInbound(ProtocolNumber, pkt) } if got, want := s.Stats().IP.MalformedPacketsReceived.Value(), test.wantMalformedIPPackets; got != want { @@ -1999,6 +2043,287 @@ func TestInvalidIPv6Fragments(t *testing.T) { if got, want := s.Stats().IP.MalformedFragmentsReceived.Value(), test.wantMalformedFragments; got != want { t.Errorf("got Stats.IP.MalformedFragmentsReceived = %d, want = %d", got, want) } + + reply, ok := e.Read() + if !test.expectICMP { + if ok { + t.Fatalf("unexpected ICMP error message received: %#v", reply) + } + return + } + if !ok { + t.Fatal("expected ICMP error message missing") + } + + checker.IPv6(t, stack.PayloadSince(reply.Pkt.NetworkHeader()), + checker.SrcAddr(addr2), + checker.DstAddr(addr1), + checker.IPFullLength(uint16(header.IPv6MinimumSize+header.ICMPv6MinimumSize+expectICMPPayload.Size())), + checker.ICMPv6( + checker.ICMPv6Type(test.expectICMPType), + checker.ICMPv6Code(test.expectICMPCode), + checker.ICMPv6TypeSpecific(test.expectICMPTypeSpecific), + checker.ICMPv6Payload([]byte(expectICMPPayload)), + ), + ) + }) + } +} + +func TestFragmentReassemblyTimeout(t *testing.T) { + const ( + addr1 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" + addr2 = "\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02" + linkAddr1 = tcpip.LinkAddress("\x0a\x0b\x0c\x0d\x0e\x0e") + nicID = 1 + hoplimit = 255 + ident = 1 + data = "TEST_FRAGMENT_REASSEMBLY_TIMEOUT" + ) + + type fragmentData struct { + ipv6Fields header.IPv6Fields + ipv6FragmentFields header.IPv6FragmentFields + payload []byte + } + + tests := []struct { + name string + fragments []fragmentData + expectICMP bool + }{ + { + name: "first fragment only", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0, + M: true, + Identification: ident, + }, + payload: []byte(data)[:16], + }, + }, + expectICMP: true, + }, + { + name: "two first fragments", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0, + M: true, + Identification: ident, + }, + payload: []byte(data)[:16], + }, + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0, + M: true, + Identification: ident, + }, + payload: []byte(data)[:16], + }, + }, + expectICMP: true, + }, + { + name: "second fragment only", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: uint16(header.IPv6FragmentHeaderSize + len(data) - 16), + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 8, + M: false, + Identification: ident, + }, + payload: []byte(data)[16:], + }, + }, + expectICMP: false, + }, + { + name: "two fragments with a gap", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0, + M: true, + Identification: ident, + }, + payload: []byte(data)[:16], + }, + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: uint16(header.IPv6FragmentHeaderSize + len(data) - 16), + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 8, + M: false, + Identification: ident, + }, + payload: []byte(data)[16:], + }, + }, + expectICMP: true, + }, + { + name: "two fragments with a gap in reverse order", + fragments: []fragmentData{ + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: uint16(header.IPv6FragmentHeaderSize + len(data) - 16), + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 8, + M: false, + Identification: ident, + }, + payload: []byte(data)[16:], + }, + { + ipv6Fields: header.IPv6Fields{ + PayloadLength: header.IPv6FragmentHeaderSize + 16, + NextHeader: header.IPv6FragmentHeader, + HopLimit: hoplimit, + SrcAddr: addr1, + DstAddr: addr2, + }, + ipv6FragmentFields: header.IPv6FragmentFields{ + NextHeader: uint8(header.UDPProtocolNumber), + FragmentOffset: 0, + M: true, + Identification: ident, + }, + payload: []byte(data)[:16], + }, + }, + expectICMP: true, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + clock := faketime.NewManualClock() + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocolFactory{ + NewProtocol, + }, + Clock: clock, + }) + + e := channel.New(1, 1500, linkAddr1) + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) + } + if err := s.AddAddress(nicID, ProtocolNumber, addr2); err != nil { + t.Fatalf("AddAddress(%d, %d, %s) = %s", nicID, header.IPv6ProtocolNumber, addr2, err) + } + s.SetRouteTable([]tcpip.Route{{ + Destination: header.IPv6EmptySubnet, + NIC: nicID, + }}) + + var firstFragmentSent buffer.View + for _, f := range test.fragments { + hdr := buffer.NewPrependable(header.IPv6MinimumSize + header.IPv6FragmentHeaderSize) + + ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize + header.IPv6FragmentHeaderSize)) + ip.Encode(&f.ipv6Fields) + + fragHDR := header.IPv6Fragment(hdr.View()[header.IPv6MinimumSize:]) + fragHDR.Encode(&f.ipv6FragmentFields) + + vv := hdr.View().ToVectorisedView() + vv.AppendView(f.payload) + + pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ + Data: vv, + }) + + if firstFragmentSent == nil && fragHDR.FragmentOffset() == 0 { + firstFragmentSent = stack.PayloadSince(pkt.NetworkHeader()) + } + + e.InjectInbound(ProtocolNumber, pkt) + } + + clock.Advance(ReassembleTimeout) + + reply, ok := e.Read() + if !test.expectICMP { + if ok { + t.Fatalf("unexpected ICMP error message received: %#v", reply) + } + return + } + if !ok { + t.Fatal("expected ICMP error message missing") + } + if firstFragmentSent == nil { + t.Fatalf("unexpected ICMP error message received: %#v", reply) + } + + checker.IPv6(t, stack.PayloadSince(reply.Pkt.NetworkHeader()), + checker.SrcAddr(addr2), + checker.DstAddr(addr1), + checker.IPFullLength(uint16(header.IPv6MinimumSize+header.ICMPv6MinimumSize+firstFragmentSent.Size())), + checker.ICMPv6( + checker.ICMPv6Type(header.ICMPv6TimeExceeded), + checker.ICMPv6Code(header.ICMPv6ReassemblyTimeout), + checker.ICMPv6Payload([]byte(firstFragmentSent)), + ), + ) }) } } |