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authorArthur Sfez <asfez@google.com>2021-04-20 00:26:54 -0700
committergVisor bot <gvisor-bot@google.com>2021-04-20 00:28:42 -0700
commit2c8379d95738bb2bc10d2cc7cead6889379e244c (patch)
treebedb4b4b222deeed6f0a2bbf1ab8362e625df3a0 /pkg/tcpip/transport/udp
parent82eecd2e93a4d2c42ca2b0b88f721f186c8712d9 (diff)
Expose header methods that validate checksums
This is done for IPv4, UDP and TCP headers. This also changes the packet checkers used in tests to error on zero-checksum, not sure why it was allowed before. And while I'm here, make comments' case consistent. RELNOTES: n/a Fixes #5049 PiperOrigin-RevId: 369383862
Diffstat (limited to 'pkg/tcpip/transport/udp')
-rw-r--r--pkg/tcpip/transport/udp/endpoint.go34
1 files changed, 21 insertions, 13 deletions
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 956da0e0c..f26c7ca10 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -1255,20 +1255,29 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
}
// verifyChecksum verifies the checksum unless RX checksum offload is enabled.
-// On IPv4, UDP checksum is optional, and a zero value means the transmitter
-// omitted the checksum generation (RFC768).
-// On IPv6, UDP checksum is not optional (RFC2460 Section 8.1).
func verifyChecksum(hdr header.UDP, pkt *stack.PacketBuffer) bool {
- if !pkt.RXTransportChecksumValidated &&
- (hdr.Checksum() != 0 || pkt.NetworkProtocolNumber == header.IPv6ProtocolNumber) {
- netHdr := pkt.Network()
- xsum := header.PseudoHeaderChecksum(ProtocolNumber, netHdr.DestinationAddress(), netHdr.SourceAddress(), hdr.Length())
- for _, v := range pkt.Data().Views() {
- xsum = header.Checksum(v, xsum)
- }
- return hdr.CalculateChecksum(xsum) == 0xffff
+ if pkt.RXTransportChecksumValidated {
+ return true
+ }
+
+ // On IPv4, UDP checksum is optional, and a zero value means the transmitter
+ // omitted the checksum generation, as per RFC 768:
+ //
+ // An all zero transmitted checksum value means that the transmitter
+ // generated no checksum (for debugging or for higher level protocols that
+ // don't care).
+ //
+ // On IPv6, UDP checksum is not optional, as per RFC 2460 Section 8.1:
+ //
+ // Unlike IPv4, when UDP packets are originated by an IPv6 node, the UDP
+ // checksum is not optional.
+ if pkt.NetworkProtocolNumber == header.IPv4ProtocolNumber && hdr.Checksum() == 0 {
+ return true
}
- return true
+
+ netHdr := pkt.Network()
+ payloadChecksum := pkt.Data().AsRange().Checksum()
+ return hdr.IsChecksumValid(netHdr.SourceAddress(), netHdr.DestinationAddress(), payloadChecksum)
}
// HandlePacket is called by the stack when new packets arrive to this transport
@@ -1284,7 +1293,6 @@ func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketB
}
if !verifyChecksum(hdr, pkt) {
- // Checksum Error.
e.stack.Stats().UDP.ChecksumErrors.Increment()
e.stats.ReceiveErrors.ChecksumErrors.Increment()
return