在 2017/9/13 14:56, liujian 写道: > > > 在 2017/9/12 23:38, Eric Dumazet 写道: >> On Tue, 2017-09-12 at 08:05 -0700, Eric Dumazet wrote: >>> On Tue, 2017-09-12 at 14:08 +0800, liujian wrote: >>>> Hi, >>>> >>>> In the scenario, tcp server side IP changed, and at that memont, >>>> userspace application still send data continuously; >>>> tcp_send_head(sk)'s timestamp always be refreshed. >>>> >>>> Here is the packetdrill script: >>>> >>>> 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 >>>> +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 >>>> +0 bind(3, ..., ...) = 0 >>>> +0 listen(3, 1) = 0 >>>> >>>> +0 < S 0:0(0) win 0 <mss 1460,sackOK,nop,nop,nop,wscale 7> >>>> +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> >>>> >>>> +.1 < . 1:1(0) ack 1 win 65530 >>>> +0 accept(3, ..., ...) = 4 >>>> >>>> +0 setsockopt(4, SOL_TCP, TCP_USER_TIMEOUT, [3000], 4) = 0 >>>> +0 write(4, ..., 24) = 24 >>>> +0 > P. 1:25(24) ack 1 win 229 >>>> +.1 < . 1:1(0) ack 25 win 65530 >>>> >>>> //change the ipaddress >>>> +1 `ifconfig tun0 192.168.0.10/16` >>>> >>>> +1 write(4, ..., 24) = 24 >>>> +1 write(4, ..., 24) = 24 >>>> +1 write(4, ..., 24) = 24 >>>> +1 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> +3 write(4, ..., 24) = 24 >>>> >>>> +0 `ifconfig tun0 192.168.0.1/16` >>>> +0 < . 1:1(0) ack 1 win 1000 >>>> +0 write(4, ..., 24) = -1 >>>> >>>> >>> >>> This has nothing to do with the code patch you have changed. >>> >>> How have you tested your patch exactly ? >>> > I tested the patch, it can work. > > [root@localhost ~]# time ./gtests/net/packetdrill/packetdrill test.pkt > test.pkt:24: runtime error in write call: Expected result 24 but got -1 with > errno 110 (Connection timed out) > > real 0m5.356s > user 0m0.026s > sys 0m0.104s > > [root@localhost ~]# ss -toenmi src :8080 > State Recv-Q Send-Q Local Address:Port > Peer Address:Port > ESTAB 0 48 192.168.0.1:8080 > 192.0.2.1:39559 timer:(persist,186ms,2) ino:37178 > sk:6 <-> > skmem:(r0,rb369280,t0,tb87040,f1792,w2304,o0,bl0) sack cubic > wscale:7,7 rto:301 backoff:2 rtt:100.253/37.643 mss:1460 cwnd:10 > bytes_acked:24 segs_out:5 segs_in:3 send 1.2Mbps lastsnd:976 lastrcv:4082 > lastack:3982 pacing_rate 2.3Mbps rcv_space:29200 > > > if change the TCP_USER_TIMEOUT to 30s, test result as below: > > [root@localhost ~]# time ./gtests/net/packetdrill/packetdrill test.pkt > test.pkt:37: runtime error in write call: Expected result 24 but got -1 with > errno 110 (Connection timed out) > > real 0m44.362s > user 0m0.018s > sys 0m0.110s > > ESTAB 0 360 192.168.0.1:8080 > 192.0.2.1:47577 timer:(persist,516ms,6) ino:18806 > sk:5 <-> > skmem:(r0,rb369280,t0,tb87040,f1792,w2304,o0,bl0) sack cubic > wscale:7,7 rto:301 backoff:6 rtt:100.228/37.623 mss:10 bytes_acked:24 > segs_out:22 segs_in:3 send 1.2Mbps lastsnd:2343 lastrcv:40450 lastack:40350 > pacing_rate 2.3Mbps rcv_sp > >> >> lpaa23:~# ss -toenmi src :8080 >> State Recv-Q Send-Q Local Address:Port Peer >> Address:Port >> ESTAB 0 144 192.168.134.161:8080 >> 192.0.2.1:51165 timer:(persist,8.262ms,5) ino:1 >> 82083 sk:3 <-> >> skmem:(r0,rb359040,t0,tb46080,f1792,w2304,o0,bl0,d0) sack cubic >> wscale:7,8 rto:301 backoff:5 rtt:100.127/37.576 >> mss:1460 rcvmss:536 advmss:1460 cwnd:10 bytes_acked:24 segs_out:12 >> segs_in:3 data_segs_out:12 send 1.2Mbps lastsnd:1370 l >> astrcv:13348 lastack:13248 pacing_rate 2.3Mbps delivery_rate 116.7Kbps >> app_limited busy:11346ms rcv_space:29200 notsent:1 >> 44 minrtt:100.043userspace application still send data continuously >> >> This is the typical RTO timer, not zero window probe. >> > with the script, it is not zero window; but the code enter tcp_probe_timer. > ->tcp_sendmsg > -->tcp_push > ---->__tcp_push_pending_frames > ------>tcp_write_xmit > -------->tcp_transmit_skb (at this function, tcp_send_head(sk)'s timestamp > was be refreshed) > ---------->ip_queue_xmit (can not find route, return -EHOSTUNREACH) > -------->tcp_transmit_skb (send fail, do not advance send head) > ------->tcp_check_probe_timer (reset ICSK_TIME_PROBE0 timer) sorry, change to ->tcp_sendmsg -->tcp_push ---->__tcp_push_pending_frames ------>tcp_write_xmit -------->tcp_transmit_skb (at this function, tcp_send_head(sk)'s timestamp was be refreshed) ---------->ip_queue_xmit (can not find route, return -EHOSTUNREACH) ------>tcp_write_xmit (send fail, do not advance send head) ------>tcp_check_probe_timer (reset ICSK_TIME_PROBE0 timer)
> Here userspace application still send data continuously, > it triggered ICSK_TIME_PROBE0 timer and tcp_send_head(sk)'s timestamp refresh. > >
