diff options
Diffstat (limited to 'pkg/tcpip/network')
| -rw-r--r-- | pkg/tcpip/network/ipv4/ipv4.go | 23 |
1 files changed, 1 insertions, 22 deletions
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 9a3dc78cb..a82a5790d 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -1178,28 +1178,7 @@ func (p *protocol) parseAndValidate(pkt *stack.PacketBuffer) (header.IPv4, bool) return nil, false } - // There has been some confusion regarding verifying checksums. We need - // just look for negative 0 (0xffff) as the checksum, as it's not possible to - // get positive 0 (0) for the checksum. Some bad implementations could get it - // when doing entry replacement in the early days of the Internet, - // however the lore that one needs to check for both persists. - // - // RFC 1624 section 1 describes the source of this confusion as: - // [the partial recalculation method described in RFC 1071] computes a - // result for certain cases that differs from the one obtained from - // scratch (one's complement of one's complement sum of the original - // fields). - // - // However RFC 1624 section 5 clarifies that if using the verification method - // "recommended by RFC 1071, it does not matter if an intermediate system - // generated a -0 instead of +0". - // - // RFC1071 page 1 specifies the verification method as: - // (3) To check a checksum, the 1's complement sum is computed over the - // same set of octets, including the checksum field. If the result - // is all 1 bits (-0 in 1's complement arithmetic), the check - // succeeds. - if h.CalculateChecksum() != 0xffff { + if !h.IsChecksumValid() { return nil, false } |