Hello,

May someone help me in understanding the meaning of the following fields of
the Liunx Kernel TCP/IP stack?

-for the struct sock:
use_write_queue /*is it set to 1 for TCP sockets and to 0 for the UDP ones ? */
-for the struct tcp opt:
frto_counter
frto_highmark

i did read the comments in the kernel code but any further description will be welcome!

thanks you

Mr.Bloom

i hope i get at least some of theis right

use_write_queue is a flag that esentially is used to distinguish between UDP and TCP

see for instance the function sock_wfree()
when it attempts to wake up possible sleepers on the socket it checks
use_write_queue
basically UDP packets don't use the que to the sk_buffs.
they just either can transmit and do or fail.
i think blocking UDP packets do go in the wait cue with the longest possible wait (when memory if full) for the sk_buffs but then again either transmit or fail. they never get into the linked lists called buffer queues that exist for each buffer don't get priority set and like that.
see include/linux/skbuff.h


all i know about the others is RTO is Retransmission
Time Out
see /include/linux/tcp.h
http://www.faqs.org/rfcs/rfc2988.html

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