diff options
Diffstat (limited to 'pkg/tcpip/header/checksum.go')
| -rw-r--r-- | pkg/tcpip/header/checksum.go | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/pkg/tcpip/header/checksum.go b/pkg/tcpip/header/checksum.go index 2c2fcbd9b..2e8c65fac 100644 --- a/pkg/tcpip/header/checksum.go +++ b/pkg/tcpip/header/checksum.go @@ -17,6 +17,8 @@ package header import ( + "encoding/binary" + "gvisor.googlesource.com/gvisor/pkg/tcpip" "gvisor.googlesource.com/gvisor/pkg/tcpip/buffer" ) @@ -76,12 +78,17 @@ func ChecksumCombine(a, b uint16) uint16 { return uint16(v + v>>16) } -// PseudoHeaderChecksum calculates the pseudo-header checksum for the -// given destination protocol and network address, ignoring the length -// field. Pseudo-headers are needed by transport layers when calculating -// their own checksum. -func PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, srcAddr tcpip.Address, dstAddr tcpip.Address) uint16 { +// PseudoHeaderChecksum calculates the pseudo-header checksum for the given +// destination protocol and network address. Pseudo-headers are needed by +// transport layers when calculating their own checksum. +func PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, srcAddr tcpip.Address, dstAddr tcpip.Address, totalLen uint16) uint16 { xsum := Checksum([]byte(srcAddr), 0) xsum = Checksum([]byte(dstAddr), xsum) + + // Add the length portion of the checksum to the pseudo-checksum. + tmp := make([]byte, 2) + binary.BigEndian.PutUint16(tmp, totalLen) + xsum = Checksum(tmp, xsum) + return Checksum([]byte{0, uint8(protocol)}, xsum) } |