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Diffstat (limited to 'pkg/tcpip/network/ipv4/icmp.go')
-rw-r--r--pkg/tcpip/network/ipv4/icmp.go160
1 files changed, 160 insertions, 0 deletions
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
new file mode 100644
index 000000000..770f56c3d
--- /dev/null
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -0,0 +1,160 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ipv4
+
+import (
+ "encoding/binary"
+
+ "gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
+ "gvisor.googlesource.com/gvisor/pkg/tcpip/header"
+ "gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
+)
+
+// handleControl handles the case when an ICMP packet contains the headers of
+// the original packet that caused the ICMP one to be sent. This information is
+// used to find out which transport endpoint must be notified about the ICMP
+// packet.
+func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, vv buffer.VectorisedView) {
+ h := header.IPv4(vv.First())
+
+ // We don't use IsValid() here because ICMP only requires that the IP
+ // header plus 8 bytes of the transport header be included. So it's
+ // likely that it is truncated, which would cause IsValid to return
+ // false.
+ //
+ // Drop packet if it doesn't have the basic IPv4 header or if the
+ // original source address doesn't match the endpoint's address.
+ if len(h) < header.IPv4MinimumSize || h.SourceAddress() != e.id.LocalAddress {
+ return
+ }
+
+ hlen := int(h.HeaderLength())
+ if vv.Size() < hlen || h.FragmentOffset() != 0 {
+ // We won't be able to handle this if it doesn't contain the
+ // full IPv4 header, or if it's a fragment not at offset 0
+ // (because it won't have the transport header).
+ return
+ }
+
+ // Skip the ip header, then deliver control message.
+ vv.TrimFront(hlen)
+ p := h.TransportProtocol()
+ e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, vv)
+}
+
+func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.VectorisedView) {
+ stats := r.Stats()
+ received := stats.ICMP.V4PacketsReceived
+ v := vv.First()
+ if len(v) < header.ICMPv4MinimumSize {
+ received.Invalid.Increment()
+ return
+ }
+ h := header.ICMPv4(v)
+
+ // TODO(b/112892170): Meaningfully handle all ICMP types.
+ switch h.Type() {
+ case header.ICMPv4Echo:
+ received.Echo.Increment()
+ if len(v) < header.ICMPv4EchoMinimumSize {
+ received.Invalid.Increment()
+ return
+ }
+
+ // Only send a reply if the checksum is valid.
+ wantChecksum := h.Checksum()
+ // Reset the checksum field to 0 to can calculate the proper
+ // checksum. We'll have to reset this before we hand the packet
+ // off.
+ h.SetChecksum(0)
+ gotChecksum := ^header.ChecksumVV(vv, 0 /* initial */)
+ if gotChecksum != wantChecksum {
+ // It's possible that a raw socket expects to receive this.
+ h.SetChecksum(wantChecksum)
+ e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv)
+ received.Invalid.Increment()
+ return
+ }
+
+ // It's possible that a raw socket expects to receive this.
+ h.SetChecksum(wantChecksum)
+ e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv)
+
+ vv := vv.Clone(nil)
+ vv.TrimFront(header.ICMPv4EchoMinimumSize)
+ hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv4EchoMinimumSize)
+ pkt := header.ICMPv4(hdr.Prepend(header.ICMPv4EchoMinimumSize))
+ copy(pkt, h)
+ pkt.SetType(header.ICMPv4EchoReply)
+ pkt.SetChecksum(^header.Checksum(pkt, header.ChecksumVV(vv, 0)))
+ sent := stats.ICMP.V4PacketsSent
+ if err := r.WritePacket(nil /* gso */, hdr, vv, header.ICMPv4ProtocolNumber, r.DefaultTTL()); err != nil {
+ sent.Dropped.Increment()
+ return
+ }
+ sent.EchoReply.Increment()
+
+ case header.ICMPv4EchoReply:
+ received.EchoReply.Increment()
+ if len(v) < header.ICMPv4EchoMinimumSize {
+ received.Invalid.Increment()
+ return
+ }
+ e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv)
+
+ case header.ICMPv4DstUnreachable:
+ received.DstUnreachable.Increment()
+ if len(v) < header.ICMPv4DstUnreachableMinimumSize {
+ received.Invalid.Increment()
+ return
+ }
+ vv.TrimFront(header.ICMPv4DstUnreachableMinimumSize)
+ switch h.Code() {
+ case header.ICMPv4PortUnreachable:
+ e.handleControl(stack.ControlPortUnreachable, 0, vv)
+
+ case header.ICMPv4FragmentationNeeded:
+ mtu := uint32(binary.BigEndian.Uint16(v[header.ICMPv4DstUnreachableMinimumSize-2:]))
+ e.handleControl(stack.ControlPacketTooBig, calculateMTU(mtu), vv)
+ }
+
+ case header.ICMPv4SrcQuench:
+ received.SrcQuench.Increment()
+
+ case header.ICMPv4Redirect:
+ received.Redirect.Increment()
+
+ case header.ICMPv4TimeExceeded:
+ received.TimeExceeded.Increment()
+
+ case header.ICMPv4ParamProblem:
+ received.ParamProblem.Increment()
+
+ case header.ICMPv4Timestamp:
+ received.Timestamp.Increment()
+
+ case header.ICMPv4TimestampReply:
+ received.TimestampReply.Increment()
+
+ case header.ICMPv4InfoRequest:
+ received.InfoRequest.Increment()
+
+ case header.ICMPv4InfoReply:
+ received.InfoReply.Increment()
+
+ default:
+ received.Invalid.Increment()
+ }
+}