On Wed, 2017-09-13 at 15:15 +0800, liujian wrote: > > 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)
OK but : 1) keepalive_time_elapsed() returns jiffies, and you compare it to a ms value. It will break on kernels with HZ=100 2) keepalive_time_elapsed() is reset every time a packet is received. With following packetdrill your patch (even if we fix 1)) breaks again # ./packetdrill --local_ip 192.168.102.64 user_timeout.pkt # cat user_timeout.pkt 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 `ifconfig tun0 192.168.102.64/16; ip ro add 192.0.2.1 dev tun0` +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 8> +.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 115 +.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 +0 `ifconfig tun0 192.168.102.64/16` +0 < . 1:2(1) ack 25 win 65530 +0 `ifconfig tun0 192.168.0.10/16` +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 I would instead try to keep a meaningful value in tcp_send_head(sk)->skb_mstamp if the transmit failed. Or more exactly change skb->skb_mstamp only on (successfully) transmitted skb. I will provide a patch ( fixing net/ipv4/tcp_output.c )
