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-rw-r--r--pkg/tcpip/header/icmpv4.go3
-rw-r--r--pkg/tcpip/network/fragmentation/fragmentation.go28
-rw-r--r--pkg/tcpip/network/fragmentation/reassembler.go22
-rw-r--r--pkg/tcpip/network/ipv4/icmp.go18
-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go27
-rw-r--r--pkg/tcpip/network/ipv6/icmp.go15
-rw-r--r--pkg/tcpip/network/ipv6/ipv6.go53
7 files changed, 150 insertions, 16 deletions
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/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/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/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,
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 11:41:02 +0000