diff options
Diffstat (limited to 'pkg/tcpip')
| -rw-r--r-- | pkg/tcpip/header/udp.go | 29 | ||||
| -rw-r--r-- | pkg/tcpip/transport/udp/endpoint.go | 7 |
2 files changed, 22 insertions, 14 deletions
diff --git a/pkg/tcpip/header/udp.go b/pkg/tcpip/header/udp.go index 98bdd29db..a6d4fcd59 100644 --- a/pkg/tcpip/header/udp.go +++ b/pkg/tcpip/header/udp.go @@ -36,10 +36,10 @@ const ( // UDPFields contains the fields of a UDP packet. It is used to describe the // fields of a packet that needs to be encoded. type UDPFields struct { - // SrcPort is the "source port" field of a UDP packet. + // SrcPort is the "Source Port" field of a UDP packet. SrcPort uint16 - // DstPort is the "destination port" field of a UDP packet. + // DstPort is the "Destination Port" field of a UDP packet. DstPort uint16 // Length is the "length" field of a UDP packet. @@ -64,52 +64,57 @@ const ( UDPProtocolNumber tcpip.TransportProtocolNumber = 17 ) -// SourcePort returns the "source port" field of the udp header. +// SourcePort returns the "Source Port" field of the UDP header. func (b UDP) SourcePort() uint16 { return binary.BigEndian.Uint16(b[udpSrcPort:]) } -// DestinationPort returns the "destination port" field of the udp header. +// DestinationPort returns the "Destination Port" field of the UDP header. func (b UDP) DestinationPort() uint16 { return binary.BigEndian.Uint16(b[udpDstPort:]) } -// Length returns the "length" field of the udp header. +// Length returns the "Length" field of the UDP header. func (b UDP) Length() uint16 { return binary.BigEndian.Uint16(b[udpLength:]) } // Payload returns the data contained in the UDP datagram. func (b UDP) Payload() []byte { - return b[UDPMinimumSize:] + return b[:b.Length()][UDPMinimumSize:] } -// Checksum returns the "checksum" field of the udp header. +// Checksum returns the "checksum" field of the UDP header. func (b UDP) Checksum() uint16 { return binary.BigEndian.Uint16(b[udpChecksum:]) } -// SetSourcePort sets the "source port" field of the udp header. +// SetSourcePort sets the "source port" field of the UDP header. func (b UDP) SetSourcePort(port uint16) { binary.BigEndian.PutUint16(b[udpSrcPort:], port) } -// SetDestinationPort sets the "destination port" field of the udp header. +// SetDestinationPort sets the "destination port" field of the UDP header. func (b UDP) SetDestinationPort(port uint16) { binary.BigEndian.PutUint16(b[udpDstPort:], port) } -// SetChecksum sets the "checksum" field of the udp header. +// SetChecksum sets the "checksum" field of the UDP header. func (b UDP) SetChecksum(checksum uint16) { binary.BigEndian.PutUint16(b[udpChecksum:], checksum) } -// SetLength sets the "length" field of the udp header. +// SetLength sets the "length" field of the UDP header. func (b UDP) SetLength(length uint16) { binary.BigEndian.PutUint16(b[udpLength:], length) } -// CalculateChecksum calculates the checksum of the udp packet, given the +// PayloadLength returns the length of the payload following the UDP header. +func (b UDP) PayloadLength() uint16 { + return b.Length() - UDPMinimumSize +} + +// CalculateChecksum calculates the checksum of the UDP packet, given the // checksum of the network-layer pseudo-header and the checksum of the payload. func (b UDP) CalculateChecksum(partialChecksum uint16) uint16 { // Calculate the rest of the checksum. diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index 5043e7aa5..ee1bb29f8 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -1267,7 +1267,6 @@ func verifyChecksum(hdr header.UDP, pkt *stack.PacketBuffer) bool { // HandlePacket is called by the stack when new packets arrive to this transport // endpoint. func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketBuffer) { - // Get the header then trim it from the view. hdr := header.UDP(pkt.TransportHeader().View()) if int(hdr.Length()) > pkt.Data.Size()+header.UDPMinimumSize { // Malformed packet. @@ -1276,6 +1275,10 @@ func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketB return } + // TODO(gvisor.dev/issues/5033): We should mirror the Network layer and cap + // packets at "Parse" instead of when handling a packet. + pkt.Data.CapLength(int(hdr.PayloadLength())) + if !verifyChecksum(hdr, pkt) { // Checksum Error. e.stack.Stats().UDP.ChecksumErrors.Increment() @@ -1309,7 +1312,7 @@ func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketB senderAddress: tcpip.FullAddress{ NIC: pkt.NICID, Addr: id.RemoteAddress, - Port: header.UDP(hdr).SourcePort(), + Port: hdr.SourcePort(), }, } packet.data = pkt.Data |