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mirror of https://github.com/wader/fq.git synced 2024-11-30 18:08:16 +03:00
fq/pkg/checksum/ipv4.go
Mattias Wadman f55b1af6ac inet: Add tcp and ipv4 reassembly
Also add tcp_stream and udp_payload to decode content
2021-11-29 18:42:18 +01:00

40 lines
637 B
Go

package checksum
// IPv4 implements hash.Hash
type IPv4 struct {
sum uint
odd bool
}
func (c *IPv4) Write(p []byte) (n int, err error) {
for _, b := range p {
if c.odd {
c.sum += uint(b)
if c.sum > 0xffff {
c.sum++
c.sum &= 0xffff
}
} else {
c.sum += uint(b) << 8
}
c.odd = !c.odd
}
return len(p), nil
}
func (c *IPv4) Sum(b []byte) []byte {
s := c.sum
if c.odd {
if s > 0xffff {
s++
s &= 0xffff
}
}
s ^= 0xffff
return append(b, byte(s>>8), byte(s))
}
func (c *IPv4) Reset() { c.sum = 0 }
func (c *IPv4) Size() int { return 2 }
func (c *IPv4) BlockSize() int { return 2 }