Module checksum 

TCP checksum calculation.

TCP uses the Internet checksum (RFC 1071) computed over a pseudo-header followed by the TCP header and payload.

IPv4 Pseudo-header

+--------+--------+--------+--------+
|           Source Address          |
+--------+--------+--------+--------+
|         Destination Address       |
+--------+--------+--------+--------+
|  zero  |  PTCL  |    TCP Length   |
+--------+--------+--------+--------+

IPv6 Pseudo-header

+--------+--------+--------+--------+
|                                   |
+                                   +
|           Source Address          |
+                                   +
|                                   |
+                                   +
|                                   |
+--------+--------+--------+--------+
|                                   |
+                                   +
|         Destination Address       |
+                                   +
|                                   |
+                                   +
|                                   |
+--------+--------+--------+--------+
|         Upper-Layer Packet Length |
+--------+--------+--------+--------+
|           zero          |Next Hdr|
+--------+--------+--------+--------+

Constants

TCP_PROTOCOL

TCP protocol number for pseudo-header.

Functions

ipv4_pseudo_header

Build the IPv4 pseudo-header bytes for TCP.

ipv6_pseudo_header

Build the IPv6 pseudo-header bytes for TCP.

tcp_checksum

Compute TCP checksum (generic version).

tcp_checksum_ipv4

Compute TCP checksum with IPv4 pseudo-header.

tcp_checksum_ipv6

Compute TCP checksum with IPv6 pseudo-header.

tcp_partial_checksum

Compute checksum for partial data (for segmented computation).

verify_tcp_checksum

Verify TCP checksum with IPv4 pseudo-header.

verify_tcp_checksum_ipv6

Verify TCP checksum with IPv6 pseudo-header.