Hi Guys,
I'm doing an implementation of T/TCP on Linux and need a bit of help here. I need to actually find out the state of the connection ; as per the actual TCP state transition diagram .So for example I need to find out how exactly to tell whether the state of the connection is SYN_SENT or CLOSING or LASTACK..etc etc . The code for this is in the kernel if I'm not mistaken ; correct me if I'm wrong . So is there any way ( API's etc ) which I can use if I want to find out the state of the client/server or do I actually have to play around with kernel modules. This is because I need to build customized T/TCP packets and a certain packet can be sent only if the client is in a particular state . If I'm not clear and anyone needs more information please do let me know .Appreciate any help .
Thanks a lot
Arvind.

I am not quite sure what you are looking for, but ethereal from ethereal.com is a great network analysis program.

netstat gives connection states in the rightmost column. not sure if that's what you want though

Not really guys..netstat does give me the states no doubt ; thats exactly what I want but I just want to know how to find the states of processes programatically ; through a piece of code without manually doing a netstat . For example ; I code a simple client - server application and there are some processes running ; some of which are in Listen , some in closing and some in established . If I do a netstat and list those processes I can see that the processes are in those states . All I need here is to write some code which I can use to actually get the states of those processes and use those states to create my packets .Hope this clarifies things a little.
Thnx
Arvind

according to strace, my netstat seems to get its information from /proc/net/tcp (and analagous files for other protocols). You can probably get the format of that file by googling around. or looking at netstat's source.