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http://article.gmane.org/gmane.linux.network/138017 From: hong liu <hong.liu96 <at> gmail.com> Subject: question about tcp_ack_update_window Newsgroups: gmane.linux.network Date: 2009-09-17 03:24:03 GMT (1 week, 5 days, 19 hours and 53 minutes ago) Hi, In tcp_ack_update_window, we don't scale the window if it's a SYN packet. This modification is introduced by Kevin Lahey during 2.5.75 (http://oss.sgi.com/archives/netdev/2003-10/msg01391.html). tcp_ack_update_window is only called by tcp_ack, which is called by tcp_rcv_synsent_state_process & tcp_rcv_established, and we change the snd_wnd back to th->window in tcp_rcv_synsent_state_process, so why we still need this check in tcp_ack_update_window? I think we may need to add tp->max_window = tp->snd_wnd in tcp_rcv_syssent_state_process if we remove the check in tcp_ack_update_window. The only problem I can see is: client entered into established state and sent an ack (the last packet in 3-way handershake) to the server, but the packet got lost / arrived slightly late. Then server resent a SYN+ACK packet, then client can get a SYN packet and call tcp_ack in tcp_rcv_established. Is this the only concern? |
