diff options
Diffstat (limited to 'pkg/tcpip/transport/udp/endpoint.go')
| -rw-r--r-- | pkg/tcpip/transport/udp/endpoint.go | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index c33434b75..0a9d3c6cf 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -1366,6 +1366,22 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask { return result } +// 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(r *stack.Route, hdr header.UDP, pkt *stack.PacketBuffer) bool { + if r.Capabilities()&stack.CapabilityRXChecksumOffload == 0 && + (hdr.Checksum() != 0 || r.NetProto == header.IPv6ProtocolNumber) { + xsum := r.PseudoHeaderChecksum(ProtocolNumber, hdr.Length()) + for _, v := range pkt.Data.Views() { + xsum = header.Checksum(v, xsum) + } + return hdr.CalculateChecksum(xsum) == 0xffff + } + return true +} + // HandlePacket is called by the stack when new packets arrive to this transport // endpoint. func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pkt *stack.PacketBuffer) { @@ -1387,22 +1403,11 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk return } - // Verify 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). - if r.Capabilities()&stack.CapabilityRXChecksumOffload == 0 && - (hdr.Checksum() != 0 || r.NetProto == header.IPv6ProtocolNumber) { - xsum := r.PseudoHeaderChecksum(ProtocolNumber, hdr.Length()) - for _, v := range pkt.Data.Views() { - xsum = header.Checksum(v, xsum) - } - if hdr.CalculateChecksum(xsum) != 0xffff { - // Checksum Error. - e.stack.Stats().UDP.ChecksumErrors.Increment() - e.stats.ReceiveErrors.ChecksumErrors.Increment() - return - } + if !verifyChecksum(r, hdr, pkt) { + // Checksum Error. + e.stack.Stats().UDP.ChecksumErrors.Increment() + e.stats.ReceiveErrors.ChecksumErrors.Increment() + return } e.stack.Stats().UDP.PacketsReceived.Increment() |