// ICMPv6 Checksum calculation
// Adapted from https://github.com/golang/net/blob/bdcab5d1425b3bc74ab0f2be70acb9e4a2b2f73e/icmp/message.go#L35
func MakeChecksum(packet Message, src, dst net.IP) uint16 {
b := packet.Marshal()
// Create new pseudo header
pHeader := ipv6.NewPseudoHeader(len(b), 0x3a, src, dst)
// append icmp bytes to pseudo header
b = append(pHeader.Marshal(), b...)
// Make checksum
return csum(b)
}
func VerifyChecksum(h *ipv6.Header, b []byte) bool {
// get checksum from package
co := binary.BigEndian.Uint16(b[2:4])
// Create pseudo header
ph := ipv6.NewPseudoHeader(h.PayloadLen, h.NextHeader, h.Src, h.Dst)
// Set checksum to 0x0
b[2] = 0
b[3] = 0
// make packet
b = append(ph.Marshal(), b...)
// calculate checksum and compare
return co == csum(b)
}