Traceroute.Protocols.TCP (traceroute v0.2.3)

Parses TCP header for extracting information from ICMP error responses.

When an ICMP error (Time Exceeded, Destination Unreachable) is received, it contains the first 8 bytes of the original TCP header, which includes the source and destination ports needed for request correlation.

Summary

Functions

parse_header(data)

Parses the first 8 bytes of a TCP header.

Functions

parse_header(data)

@spec parse_header(binary()) :: Traceroute.Protocols.TCP.Header.t()

Parses the first 8 bytes of a TCP header.

This is sufficient for extracting the source port, destination port, and sequence number from ICMP error responses.

TCP Header Structure (first 8 bytes):

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Source Port          |       Destination Port        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                        Sequence Number                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+