On Mon, 2017-09-11 at 14:27 +0800, liujia...@huawei.com wrote: > From: liujian <liujia...@huawei.com> > > After the tcp socket go to ESTABLISHED stat, change IP address (server > side), > then the tcp socket will go tcp_probe_timer process. > > [root@localhost net]# netstat -toe > Active Internet connections (w/o servers) > Proto Recv-Q Send-Q Local Address Foreign Address State > User Inode Timer > tcp 0 1104 9.81.254:personal-agent 9.84.201.213:23597 > ESTABLISHED root 12819 probe (4.36/0/7) > [root@localhost net]# cat /proc/net/tcp > sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt > uid timeout inode > 3: B1FE5109:15B3 D5C95409:5C2D 01 00000495:00000000 04:0000005E 00000000 > 0 7 12819 2 ffff95cdcf45a000 20 4 1 10 -1 > > In my test case, tcp_write_queue_head(sk) and tcp_send_head(sk) is same > SKB. > And ((s32)(tcp_time_stamp(tp) - start_ts) > > jiffies_to_msecs(icsk->icsk_user_timeout)) > always is false.
Interesting. > Here use keepalive_time_elapsed(tp) to do the compare as > tcp_keepalive_timer do. But zero window probe and TCP_USER_TIMEOUT can be used without keepalives... A packetdrill test would help, I will write one. Thanks.
