Re: accessing IP packet header

[Guy Harris <guy () alum mit edu>]

lalani () cs fsu edu wrote:

>  I wanted to access IP packet and then subsequently UDP/TCP/ICMP/IGMP 
> packet information. Are there any explicit function which I can call to 
> get information like version, IHL, source port, destination port, etc. 
> to get that information for each IP type of packet.

Not in libpcap.

See the tcpdump.org libpcap tutorial at

        http://www.tcpdump.org/pcap.htm

for some information on how to write your own code to find the IP header 
in a packet (the example is for Ethernet) and extract fields from it, 
and how to find the TCP (or other transport layer) header.
-
This is the tcpdump-workers list.
Visit https://lists.sandelman.ca/ to unsubscribe.