| Message ID | alpine.DEB.2.10.1410222039170.7882@blackhole.kfki.hu |
|---|---|
| State | RFC |
| Delegated to: | Pablo Neira |
| Headers | show |
Thanks, Jozsef. Attached is the new packet capture and trace with patch applied. On Wed, Oct 22, 2014 at 2:37 PM, Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> wrote: > On Tue, 21 Oct 2014, vDev wrote: > >> I am unable to post a pcap file at this point but here is an ASCII >> output. The last ACK (ID: 6200) was considered invalid due to III >> evaluating to 0 and res=0 in the earlier trace. > > That cannot be the last ACK, because it's a FIN, ACK packet: > >> Linux_Router.1026 > REMOTE_SERVER.63001: Flags [F.], cksum 0xf632 >> (correct), seq 31, ack 20, win 1500, length 0 >> 16:39:35.328857 IP (tos 0x0, ttl 52, id 6200, offset 0, flags [DF], >> proto TCP (6), length 40) > > However, this is still not enough. The debug lines corresponding to the > captured packets are required too. Moreover, previously there were packets > skipping the window checking in the debug log, without enough debug data > to identify them: > >> <7>[ 2238.870000] tcp_conntracks: >> <7>[ 2238.870000] syn=0 ack=1 fin=0 rst=0 old=3 new=3 >> <7>[ 2238.870000] tcp_conntracks: >> <7>[ 2238.870000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 > > So please apply this small patch, which adds the missing debug info: > > diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c > index 44d1ea3..655170f 100644 > --- a/net/netfilter/nf_conntrack_proto_tcp.c > +++ b/net/netfilter/nf_conntrack_proto_tcp.c > @@ -830,12 +830,16 @@ static int tcp_packet(struct nf_conn *ct, > th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); > BUG_ON(th == NULL); > > + pr_debug("tcp_packet: "); > spin_lock_bh(&ct->lock); > old_state = ct->proto.tcp.state; > dir = CTINFO2DIR(ctinfo); > index = get_conntrack_index(th); > new_state = tcp_conntracks[dir][index][old_state]; > tuple = &ct->tuplehash[dir].tuple; > + pr_debug("dir=%u, seq=%u ack=%u win=%u end=%u\n", > + dir, ntohl(th->seq), ntohl(th->ack_seq), ntohs(th->window), > + segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th)); > > switch (new_state) { > case TCP_CONNTRACK_SYN_SENT: > > > and send me the kernel debug messages and the tcpdump recording of the > packet flow. If you must send the tcpdump in ascii, then print absolute > and not relative TCP sequence numbers. > > At the moment the only thing I see about the packet flow is that the first > reply packet answering the first FIN does not ack the FIN flag itself. > However the TCP conntrack state table advances the state to CLOSE_WAIT, > instead of keeping the FIN_WAIT state. But that's still not a problem > in handling the next packets. > > Best regards, > Jozsef > - > E-mail : kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.mta.hu > PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt > Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences > H-1525 Budapest 114, POB. 49, Hungary root /tmp # tcpdump -n -XX -vv -S -i eth2 host Remote_Server tcpdump: listening on eth2, link-type EN10MB (Ethernet), capture size 262144 bytes 16:20:20.820187 IP (tos 0x0, ttl 63, id 1628, offset 0, flags [none], proto TCP (6), length 44) Linux_Router.1039 > Remote_Server.63001: Flags [S], cksum 0xde22 (correct), seq 2561327104, win 1500, options [mss 536], length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 002c 065c 0000 3f06 1081 434e 77fb 0cb3 .,.\..?...CNw... 0x0020: 9cf3 040f f619 98aa c000 0000 0000 6002 ..............`. 0x0030: 05dc de22 0000 0204 0218 ..."...... 16:20:20.876252 IP (tos 0x0, ttl 52, id 0, offset 0, flags [DF], proto TCP (6), length 44) Remote_Server.63001 > Linux_Router.1039: Flags [S.], cksum 0x428b (correct), seq 3661860374, ack 2561327105, win 14600, options [mss 536], length 0 0x0000: 0041 ac00 256a 001d b5cf 433d 0800 4500 .A..%j....C=..E. 0x0010: 002c 0000 4000 3406 e1dc 0cb3 9cf3 434e .,..@.4.......CN 0x0020: 77fb f619 040f da43 8e16 98aa c001 6012 w......C......`. 0x0030: 3908 428b 0000 0204 0218 0000 9.B......... 16:20:20.886805 IP (tos 0x0, ttl 63, id 1629, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [.], cksum 0x89d8 (correct), seq 2561327105, ack 3661860375, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 065d 0000 3f06 1084 434e 77fb 0cb3 .(.]..?...CNw... 0x0020: 9cf3 040f f619 98aa c001 da43 8e17 5010 ...........C..P. 0x0030: 05dc 89d8 0000 ...... 16:20:21.593340 IP (tos 0x0, ttl 63, id 1630, offset 0, flags [none], proto TCP (6), length 70) Linux_Router.1039 > Remote_Server.63001: Flags [P.], cksum 0xe81a (correct), seq 2561327105:2561327135, ack 3661860375, win 1500, length 30 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0046 065e 0000 3f06 1065 434e 77fb 0cb3 .F.^..?..eCNw... 0x0020: 9cf3 040f f619 98aa c001 da43 8e17 5018 ...........C..P. 0x0030: 05dc e81a 0000 024d 3533 3033 3130 3030 .......M53031000 0x0040: 4c30 3030 3038 301c 4035 1c1c 1c1c 302e L000080.@5....0. 0x0050: 3030 2303 00#. 16:20:21.652968 IP (tos 0x0, ttl 52, id 24150, offset 0, flags [DF], proto TCP (6), length 40) Remote_Server.63001 > Linux_Router.1039: Flags [.], cksum 0x568e (correct), seq 3661860375, ack 2561327135, win 14600, length 0 0x0000: 0041 ac00 256a 001d b5cf 433d 0800 4500 .A..%j....C=..E. 0x0010: 0028 5e56 4000 3406 838a 0cb3 9cf3 434e .(^V@.4.......CN 0x0020: 77fb f619 040f da43 8e17 98aa c01f 5010 w......C......P. 0x0030: 3908 568e 0000 0000 0000 0000 9.V......... 16:20:21.653394 IP (tos 0x0, ttl 52, id 24151, offset 0, flags [DF], proto TCP (6), length 58) Remote_Server.63001 > Linux_Router.1039: Flags [P.], cksum 0x5a3e (correct), seq 3661860375:3661860393, ack 2561327135, win 14600, length 18 0x0000: 0041 ac00 256a 001d b5cf 433d 0800 4500 .A..%j....C=..E. 0x0010: 003a 5e57 4000 3406 8377 0cb3 9cf3 434e .:^W@.4..w....CN 0x0020: 77fb f619 040f da43 8e17 98aa c01f 5018 w......C......P. 0x0030: 3908 5a3e 0000 0245 5252 4f52 3a20 4241 9.Z>...ERROR:.BA 0x0040: 4420 5343 414e 0339 D.SCAN.9 16:20:21.653783 IP (tos 0x0, ttl 52, id 24152, offset 0, flags [DF], proto TCP (6), length 40) Remote_Server.63001 > Linux_Router.1039: Flags [F.], cksum 0x567b (correct), seq 3661860393, ack 2561327135, win 14600, length 0 0x0000: 0041 ac00 256a 001d b5cf 433d 0800 4500 .A..%j....C=..E. 0x0010: 0028 5e58 4000 3406 8388 0cb3 9cf3 434e .(^X@.4.......CN 0x0020: 77fb f619 040f da43 8e29 98aa c01f 5011 w......C.)....P. 0x0030: 3908 567b 0000 0000 0000 0000 9.V{........ 16:20:21.664588 IP (tos 0x0, ttl 63, id 1631, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [.], cksum 0x89a8 (correct), seq 2561327135, ack 3661860393, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 065f 0000 3f06 1082 434e 77fb 0cb3 .(._..?...CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e29 5010 ...........C.)P. 0x0030: 05dc 89a8 0000 ...... 16:20:21.671235 IP (tos 0x0, ttl 63, id 1632, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0660 0000 3f06 1081 434e 77fb 0cb3 .(.`..?...CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:21.726839 IP (tos 0x0, ttl 52, id 24153, offset 0, flags [DF], proto TCP (6), length 40) Remote_Server.63001 > Linux_Router.1039: Flags [.], cksum 0x567a (correct), seq 3661860394, ack 2561327136, win 14600, length 0 0x0000: 0041 ac00 256a 001d b5cf 433d 0800 4500 .A..%j....C=..E. 0x0010: 0028 5e59 4000 3406 8387 0cb3 9cf3 434e .(^Y@.4.......CN 0x0020: 77fb f619 040f da43 8e2a 98aa c020 5010 w......C.*....P. 0x0030: 3908 567a 0000 0000 0000 0000 9.Vz........ 16:20:21.727338 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [R], cksum 0xf7fc (correct), seq 2561327136, win 0, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0000 4000 4006 d5e0 434e 77fb 0cb3 .(..@.@...CNw... 0x0020: 9cf3 040f f619 98aa c020 0000 0000 5004 ..............P. 0x0030: 0000 f7fc 0000 ...... 16:20:24.676125 IP (tos 0x0, ttl 63, id 1633, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0661 0000 3f06 1080 434e 77fb 0cb3 .(.a..?...CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:27.715963 IP (tos 0x0, ttl 63, id 1634, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0662 0000 3f06 107f 434e 77fb 0cb3 .(.b..?...CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:30.755758 IP (tos 0x0, ttl 63, id 1635, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0663 0000 3f06 107e 434e 77fb 0cb3 .(.c..?..~CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:33.795670 IP (tos 0x0, ttl 63, id 1636, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0664 0000 3f06 107d 434e 77fb 0cb3 .(.d..?..}CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:36.835543 IP (tos 0x0, ttl 63, id 1637, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0665 0000 3f06 107c 434e 77fb 0cb3 .(.e..?..|CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:39.875373 IP (tos 0x0, ttl 63, id 1638, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0666 0000 3f06 107b 434e 77fb 0cb3 .(.f..?..{CNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:42.915207 IP (tos 0x0, ttl 63, id 1639, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0667 0000 3f06 107a 434e 77fb 0cb3 .(.g..?..zCNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:45.955108 IP (tos 0x0, ttl 63, id 1641, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 0669 0000 3f06 1078 434e 77fb 0cb3 .(.i..?..xCNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:48.994909 IP (tos 0x0, ttl 63, id 1642, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 066a 0000 3f06 1077 434e 77fb 0cb3 .(.j..?..wCNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:52.034766 IP (tos 0x0, ttl 63, id 1643, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [F.], cksum 0x89a6 (correct), seq 2561327135, ack 3661860394, win 1500, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 066b 0000 3f06 1076 434e 77fb 0cb3 .(.k..?..vCNw... 0x0020: 9cf3 040f f619 98aa c01f da43 8e2a 5011 ...........C.*P. 0x0030: 05dc 89a6 0000 ...... 16:20:55.074560 IP (tos 0x0, ttl 63, id 1644, offset 0, flags [none], proto TCP (6), length 40) Linux_Router.1039 > Remote_Server.63001: Flags [R], cksum 0xbef5 (correct), seq 2561341735, win 0, length 0 0x0000: 001d b5cf 433d 0041 ac00 256a 0800 4500 ....C=.A..%j..E. 0x0010: 0028 066c 0000 3f06 1075 434e 77fb 0cb3 .(.l..?..uCNw... 0x0020: 9cf3 040f f619 98aa f927 0000 0000 5004 .........'....P. 0x0030: 0000 bef5 0000 ...... 22 packets captured 22 packets received by filter 0 packets dropped by kernel root /tmp # dmesg 0] device eth2 entered promiscuous mode [ 251.250000] tcp_new: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 251.250000] tcp_packet: [ 251.250000] dir=0, seq=2054078464 ack=0 win=1500 end=2054078465 [ 251.250000] tcp_in_window: START [ 251.250000] tcp_in_window: [ 251.250000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 251.250000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 251.250000] tcp_in_window: [ 251.250000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 251.250000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 251.250000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 251.250000] tcp_in_window: res=1 sender end=2054078465 maxend=2054078465 maxwin=1500 receiver end=0 maxend=1500 maxwin=0 [ 251.250000] tcp_conntracks: [ 251.250000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 254.300000] tcp_new: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 254.300000] tcp_packet: [ 254.300000] dir=0, seq=2054078464 ack=0 win=1500 end=2054078465 [ 254.300000] tcp_in_window: START [ 254.300000] tcp_in_window: [ 254.300000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 254.300000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 254.300000] tcp_in_window: [ 254.300000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 254.300000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 254.300000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 254.300000] tcp_in_window: res=1 sender end=2054078465 maxend=2054078465 maxwin=1500 receiver end=0 maxend=1500 maxwin=0 [ 254.300000] tcp_conntracks: [ 254.300000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 257.370000] tcp_new: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 257.370000] tcp_packet: [ 257.370000] dir=0, seq=2054078464 ack=0 win=1500 end=2054078465 [ 257.370000] tcp_in_window: START [ 257.370000] tcp_in_window: [ 257.370000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 257.370000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 257.370000] tcp_in_window: [ 257.370000] seq=2054078464 ack=0+(0) sack=0+(0) win=1500 end=2054078465 [ 257.370000] tcp_in_window: sender end=2054078465 maxend=2054078465 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 257.370000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 257.370000] tcp_in_window: res=1 sender end=2054078465 maxend=2054078465 maxwin=1500 receiver end=0 maxend=1500 maxwin=0 [ 257.370000] tcp_conntracks: [ 257.370000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 258.860000] device eth2 left promiscuous mode [ 260.430000] nf_ct_tcp: invalid new deleting. [ 283.400000] tcp_new: sender end=736947074 maxend=736947074 maxwin=8192 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 283.400000] tcp_packet: [ 283.400000] dir=0, seq=736947073 ack=0 win=8192 end=736947074 [ 283.400000] tcp_in_window: START [ 283.400000] tcp_in_window: [ 283.400000] seq=736947073 ack=0+(0) sack=0+(0) win=8192 end=736947074 [ 283.400000] tcp_in_window: sender end=736947074 maxend=736947074 maxwin=8192 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 283.400000] tcp_in_window: [ 283.400000] seq=736947073 ack=0+(0) sack=0+(0) win=8192 end=736947074 [ 283.400000] tcp_in_window: sender end=736947074 maxend=736947074 maxwin=8192 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 283.400000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 283.400000] tcp_in_window: res=1 sender end=736947074 maxend=736947074 maxwin=8192 receiver end=0 maxend=8192 maxwin=0 [ 283.400000] tcp_conntracks: [ 283.400000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 283.400000] tcp_packet: [ 283.400000] dir=1, seq=0 ack=736947074 win=0 end=0 [ 283.400000] tcp_conntracks: [ 283.400000] syn=0 ack=1 fin=0 rst=1 old=1 new=8 [ 354.430000] console setup [ 368.820000] device eth2 entered promiscuous mode [ 376.100000] tcp_new: sender end=2561327105 maxend=2561327105 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 376.100000] tcp_packet: [ 376.100000] dir=0, seq=2561327104 ack=0 win=1500 end=2561327105 [ 376.100000] tcp_in_window: START [ 376.100000] tcp_in_window: [ 376.100000] seq=2561327104 ack=0+(0) sack=0+(0) win=1500 end=2561327105 [ 376.100000] tcp_in_window: sender end=2561327105 maxend=2561327105 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 376.100000] tcp_in_window: [ 376.100000] seq=2561327104 ack=0+(0) sack=0+(0) win=1500 end=2561327105 [ 376.100000] tcp_in_window: sender end=2561327105 maxend=2561327105 maxwin=1500 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 376.100000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.100000] tcp_in_window: res=1 sender end=2561327105 maxend=2561327105 maxwin=1500 receiver end=0 maxend=1500 maxwin=0 [ 376.100000] tcp_conntracks: [ 376.100000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 376.160000] tcp_packet: [ 376.160000] dir=1, seq=3661860374 ack=2561327105 win=14600 end=3661860375 [ 376.160000] tcp_in_window: START [ 376.160000] tcp_in_window: [ 376.160000] seq=3661860374 ack=2561327105+(0) sack=2561327105+(0) win=14600 end=3661860375 [ 376.160000] tcp_in_window: sender end=0 maxend=1500 maxwin=0 scale=0 receiver end=2561327105 maxend=2561327105 maxwin=1500 scale=0 [ 376.160000] tcp_in_window: [ 376.160000] seq=3661860374 ack=2561327105+(0) sack=2561327105+(0) win=14600 end=3661860375 [ 376.160000] tcp_in_window: sender end=3661860375 maxend=3661860375 maxwin=14600 scale=0 receiver end=2561327105 maxend=2561327105 maxwin=1500 scale=0 [ 376.160000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.160000] tcp_in_window: res=1 sender end=3661860375 maxend=3661860375 maxwin=14600 receiver end=2561327105 maxend=2561341705 maxwin=1500 [ 376.160000] tcp_conntracks: [ 376.160000] syn=1 ack=1 fin=0 rst=0 old=1 new=2 [ 376.170000] tcp_packet: [ 376.170000] dir=0, seq=2561327105 ack=3661860375 win=1500 end=2561327105 [ 376.170000] tcp_in_window: START [ 376.170000] tcp_in_window: [ 376.170000] seq=2561327105 ack=3661860375+(0) sack=3661860375+(0) win=1500 end=2561327105 [ 376.170000] tcp_in_window: sender end=2561327105 maxend=2561341705 maxwin=1500 scale=0 receiver end=3661860375 maxend=3661860375 maxwin=14600 scale=0 [ 376.170000] tcp_in_window: [ 376.170000] seq=2561327105 ack=3661860375+(0) sack=3661860375+(0) win=1500 end=2561327105 [ 376.170000] tcp_in_window: sender end=2561327105 maxend=2561341705 maxwin=1500 scale=0 receiver end=3661860375 maxend=3661860375 maxwin=14600 scale=0 [ 376.170000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.170000] tcp_in_window: res=1 sender end=2561327105 maxend=2561341705 maxwin=1500 receiver end=3661860375 maxend=3661861875 maxwin=14600 [ 376.170000] tcp_conntracks: [ 376.170000] syn=0 ack=1 fin=0 rst=0 old=2 new=3 [ 376.880000] tcp_packet: [ 376.880000] dir=0, seq=2561327105 ack=3661860375 win=1500 end=2561327135 [ 376.880000] tcp_in_window: START [ 376.880000] tcp_in_window: [ 376.880000] seq=2561327105 ack=3661860375+(0) sack=3661860375+(0) win=1500 end=2561327135 [ 376.880000] tcp_in_window: sender end=2561327105 maxend=2561341705 maxwin=1500 scale=0 receiver end=3661860375 maxend=3661861875 maxwin=14600 scale=0 [ 376.880000] tcp_in_window: [ 376.880000] seq=2561327105 ack=3661860375+(0) sack=3661860375+(0) win=1500 end=2561327135 [ 376.880000] tcp_in_window: sender end=2561327105 maxend=2561341705 maxwin=1500 scale=0 receiver end=3661860375 maxend=3661861875 maxwin=14600 scale=0 [ 376.880000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.880000] tcp_in_window: res=1 sender end=2561327135 maxend=2561341705 maxwin=1500 receiver end=3661860375 maxend=3661861875 maxwin=14600 [ 376.880000] tcp_conntracks: [ 376.880000] syn=0 ack=1 fin=0 rst=0 old=3 new=3 [ 376.950000] tcp_packet: [ 376.950000] dir=1, seq=3661860375 ack=2561327135 win=14600 end=3661860375 [ 376.950000] tcp_in_window: START [ 376.950000] tcp_in_window: [ 376.950000] seq=3661860375 ack=2561327135+(0) sack=2561327135+(0) win=14600 end=3661860375 [ 376.950000] tcp_in_window: sender end=3661860375 maxend=3661861875 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341705 maxwin=1500 scale=0 [ 376.950000] tcp_in_window: [ 376.950000] seq=3661860375 ack=2561327135+(0) sack=2561327135+(0) win=14600 end=3661860375 [ 376.950000] tcp_in_window: sender end=3661860375 maxend=3661861875 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341705 maxwin=1500 scale=0 [ 376.950000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.950000] tcp_in_window: res=1 sender end=3661860375 maxend=3661861875 maxwin=14600 receiver end=2561327135 maxend=2561341735 maxwin=1500 [ 376.950000] tcp_conntracks: [ 376.950000] syn=0 ack=1 fin=0 rst=0 old=3 new=3 [ 376.950000] tcp_packet: [ 376.950000] dir=1, seq=3661860375 ack=2561327135 win=14600 end=3661860393 [ 376.950000] tcp_in_window: START [ 376.950000] tcp_in_window: [ 376.950000] seq=3661860375 ack=2561327135+(0) sack=2561327135+(0) win=14600 end=3661860393 [ 376.950000] tcp_in_window: sender end=3661860375 maxend=3661861875 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341735 maxwin=1500 scale=0 [ 376.950000] tcp_in_window: [ 376.950000] seq=3661860375 ack=2561327135+(0) sack=2561327135+(0) win=14600 end=3661860393 [ 376.950000] tcp_in_window: sender end=3661860375 maxend=3661861875 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341735 maxwin=1500 scale=0 [ 376.950000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.950000] tcp_in_window: res=1 sender end=3661860393 maxend=3661861875 maxwin=14600 receiver end=2561327135 maxend=2561341735 maxwin=1500 [ 376.950000] tcp_conntracks: [ 376.950000] syn=0 ack=1 fin=0 rst=0 old=3 new=3 [ 376.950000] tcp_packet: [ 376.950000] dir=1, seq=3661860393 ack=2561327135 win=14600 end=3661860394 [ 376.950000] tcp_conntracks: [ 376.950000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 [ 376.960000] tcp_packet: [ 376.960000] dir=0, seq=2561327135 ack=3661860393 win=1500 end=2561327135 [ 376.960000] tcp_in_window: START [ 376.960000] tcp_in_window: [ 376.960000] seq=2561327135 ack=3661860393+(0) sack=3661860393+(0) win=1500 end=2561327135 [ 376.960000] tcp_in_window: sender end=2561327135 maxend=2561341735 maxwin=1500 scale=0 receiver end=3661860393 maxend=3661861875 maxwin=14600 scale=0 [ 376.960000] tcp_in_window: [ 376.960000] seq=2561327135 ack=3661860393+(0) sack=3661860393+(0) win=1500 end=2561327135 [ 376.960000] tcp_in_window: sender end=2561327135 maxend=2561341735 maxwin=1500 scale=0 receiver end=3661860393 maxend=3661861875 maxwin=14600 scale=0 [ 376.960000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 376.960000] tcp_in_window: res=1 sender end=2561327135 maxend=2561341735 maxwin=1500 receiver end=3661860393 maxend=3661861893 maxwin=14600 [ 376.960000] tcp_conntracks: [ 376.960000] syn=0 ack=1 fin=0 rst=0 old=4 new=5 [ 376.960000] tcp_packet: [ 376.960000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 376.960000] tcp_conntracks: [ 376.960000] syn=0 ack=1 fin=1 rst=0 old=5 new=6 [ 377.020000] tcp_packet: [ 377.020000] dir=1, seq=3661860394 ack=2561327136 win=14600 end=3661860394 [ 377.020000] tcp_in_window: START [ 377.020000] tcp_in_window: [ 377.020000] seq=3661860394 ack=2561327136+(0) sack=2561327136+(0) win=14600 end=3661860394 [ 377.020000] tcp_in_window: sender end=3661860393 maxend=3661861893 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341735 maxwin=1500 scale=0 [ 377.020000] tcp_in_window: [ 377.020000] seq=3661860393 ack=2561327136+(0) sack=2561327136+(0) win=14600 end=3661860393 [ 377.020000] tcp_in_window: sender end=3661860393 maxend=3661861893 maxwin=14600 scale=0 receiver end=2561327135 maxend=2561341735 maxwin=1500 scale=0 [ 377.020000] tcp_in_window: I=1 II=1 III=0 IV=1 [ 377.020000] tcp_in_window: res=0 sender end=3661860393 maxend=3661861893 maxwin=14600 receiver end=2561327135 maxend=2561341735 maxwin=1500 [ 377.020000] nf_ct_tcp: invalid new deleting. [ 379.990000] tcp_packet: [ 379.990000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 379.990000] tcp_conntracks: [ 379.990000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 383.060000] tcp_packet: [ 383.060000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 383.060000] tcp_conntracks: [ 383.060000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 386.120000] tcp_packet: [ 386.120000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 386.120000] tcp_conntracks: [ 386.120000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 389.190000] tcp_packet: [ 389.190000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 389.190000] tcp_conntracks: [ 389.190000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 392.250000] tcp_packet: [ 392.250000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 392.250000] tcp_conntracks: [ 392.250000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 395.310000] tcp_packet: [ 395.310000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 395.310000] tcp_conntracks: [ 395.310000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 398.380000] tcp_packet: [ 398.380000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 398.380000] tcp_conntracks: [ 398.380000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 401.440000] tcp_packet: [ 401.440000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 401.440000] tcp_conntracks: [ 401.440000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 404.510000] tcp_packet: [ 404.510000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 404.510000] tcp_conntracks: [ 404.510000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 407.570000] tcp_packet: [ 407.570000] dir=0, seq=2561327135 ack=3661860394 win=1500 end=2561327136 [ 407.570000] tcp_conntracks: [ 407.570000] syn=0 ack=1 fin=1 rst=0 old=6 new=6 [ 410.640000] tcp_packet: [ 410.640000] dir=0, seq=2561341735 ack=0 win=0 end=2561341735 [ 410.640000] tcp_conntracks: [ 410.640000] syn=0 ack=0 fin=0 rst=1 old=6 new=8 [ 416.860000] device eth2 left promiscuous mode [ 418.060000] tcp_new: sender end=499646465 maxend=499646465 maxwin=16384 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 418.060000] tcp_packet: [ 418.060000] dir=0, seq=499646464 ack=0 win=16384 end=499646465 [ 418.060000] tcp_in_window: START [ 418.060000] tcp_in_window: [ 418.060000] seq=499646464 ack=0+(0) sack=0+(0) win=16384 end=499646465 [ 418.060000] tcp_in_window: sender end=499646465 maxend=499646465 maxwin=16384 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 418.060000] tcp_in_window: [ 418.060000] seq=499646464 ack=0+(0) sack=0+(0) win=16384 end=499646465 [ 418.060000] tcp_in_window: sender end=499646465 maxend=499646465 maxwin=16384 scale=0 receiver end=0 maxend=0 maxwin=0 scale=0 [ 418.060000] tcp_in_window: I=1 II=1 III=1 IV=1 [ 418.060000] tcp_in_window: res=1 sender end=499646465 maxend=499646465 maxwin=16384 receiver end=0 maxend=16384 maxwin=0 [ 418.060000] tcp_conntracks: [ 418.060000] syn=1 ack=0 fin=0 rst=0 old=0 new=1 [ 418.060000] tcp_packet: [ 418.060000] dir=1, seq=0 ack=499646465 win=0 end=0 [ 418.060000] tcp_conntracks: [ 418.060000] syn=0 ack=1 fin=0 rst=1 old=1 new=8 root /tmp # CTRL-A Z for help | 38400 8N1 | NOR | Minicom 2.2 | VT102 | Offline
That cannot be the last ACK, because it's a FIN, ACK packet: > Linux_Router.1026 > REMOTE_SERVER.63001: Flags [F.], cksum 0xf632 > (correct), seq 31, ack 20, win 1500, length 0 > 16:39:35.328857 IP (tos 0x0, ttl 52, id 6200, offset 0, flags [DF], > proto TCP (6), length 40) You looked at the previous packet. The correct packet is: 16:39:35.328857 IP (tos 0x0, ttl 52, id 6200, offset 0, flags [DF], proto TCP (6), length 40) REMOTE_SERVER.63001 > Linux_Router.1026: Flags [.], cksum 0xc306 (correct), seq 20, ack 32, win 14600, length 0 On Wed, Oct 22, 2014 at 4:42 PM, vDev <vijaypas@gmail.com> wrote: > Thanks, Jozsef. Attached is the new packet capture and trace with patch applied. > > > > On Wed, Oct 22, 2014 at 2:37 PM, Jozsef Kadlecsik > <kadlec@blackhole.kfki.hu> wrote: >> On Tue, 21 Oct 2014, vDev wrote: >> >>> I am unable to post a pcap file at this point but here is an ASCII >>> output. The last ACK (ID: 6200) was considered invalid due to III >>> evaluating to 0 and res=0 in the earlier trace. >> >> That cannot be the last ACK, because it's a FIN, ACK packet: >> >>> Linux_Router.1026 > REMOTE_SERVER.63001: Flags [F.], cksum 0xf632 >>> (correct), seq 31, ack 20, win 1500, length 0 >>> 16:39:35.328857 IP (tos 0x0, ttl 52, id 6200, offset 0, flags [DF], >>> proto TCP (6), length 40) >> >> However, this is still not enough. The debug lines corresponding to the >> captured packets are required too. Moreover, previously there were packets >> skipping the window checking in the debug log, without enough debug data >> to identify them: >> >>> <7>[ 2238.870000] tcp_conntracks: >>> <7>[ 2238.870000] syn=0 ack=1 fin=0 rst=0 old=3 new=3 >>> <7>[ 2238.870000] tcp_conntracks: >>> <7>[ 2238.870000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 >> >> So please apply this small patch, which adds the missing debug info: >> >> diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c >> index 44d1ea3..655170f 100644 >> --- a/net/netfilter/nf_conntrack_proto_tcp.c >> +++ b/net/netfilter/nf_conntrack_proto_tcp.c >> @@ -830,12 +830,16 @@ static int tcp_packet(struct nf_conn *ct, >> th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); >> BUG_ON(th == NULL); >> >> + pr_debug("tcp_packet: "); >> spin_lock_bh(&ct->lock); >> old_state = ct->proto.tcp.state; >> dir = CTINFO2DIR(ctinfo); >> index = get_conntrack_index(th); >> new_state = tcp_conntracks[dir][index][old_state]; >> tuple = &ct->tuplehash[dir].tuple; >> + pr_debug("dir=%u, seq=%u ack=%u win=%u end=%u\n", >> + dir, ntohl(th->seq), ntohl(th->ack_seq), ntohs(th->window), >> + segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th)); >> >> switch (new_state) { >> case TCP_CONNTRACK_SYN_SENT: >> >> >> and send me the kernel debug messages and the tcpdump recording of the >> packet flow. If you must send the tcpdump in ascii, then print absolute >> and not relative TCP sequence numbers. >> >> At the moment the only thing I see about the packet flow is that the first >> reply packet answering the first FIN does not ack the FIN flag itself. >> However the TCP conntrack state table advances the state to CLOSE_WAIT, >> instead of keeping the FIN_WAIT state. But that's still not a problem >> in handling the next packets. >> >> Best regards, >> Jozsef >> - >> E-mail : kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.mta.hu >> PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt >> Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences >> H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 22 Oct 2014, vDev wrote: > Thanks, Jozsef. Attached is the new packet capture and trace with patch > applied. Thanks, now packets and conntrack states can be compared. Up to packet 6 everything is normal. However, look at packet 7: 16:20:21.653783 IP (tos 0x0, ttl 52, id 24152, offset 0, flags [DF], proto TCP (6), length 40) Remote_Server.63001 > Linux_Router.1039: Flags [F.], cksum 0x567b (correct), seq 3661860393, ack 2561327135, win 14600, length 0 This is the first FIN packet, and the kernel debug log says: [ 376.950000] tcp_packet: [ 376.950000] dir=1, seq=3661860393 ack=2561327135 win=14600 end=3661860394 [ 376.950000] tcp_conntracks: [ 376.950000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 The previous conntrack state is in "old=3", i.e. TCP_CONNTRACK_ESTABLISHED. The new=4 means TCP_CONNTRACK_FIN_WAIT. However between [ 376.950000] tcp_packet: [ 376.950000] dir=1, seq=3661860393 ack=2561327135 win=14600 end=3661860394 and [ 376.950000] tcp_conntracks: [ 376.950000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 there is a missing the call to tcp_in_window()! Therefore the internal counters of conntrack is not updated and later packets won't match the wrong internal states. Why the call to tcp_in_window() is missing? Looking at tcp_packet(), there's nothing which could cause skipping it: the big switch about the new_state does not divert the handling of TCP_CONNTRACK_FIN_WAIT. So, what's your kernel version number? You have got the source: please post net/netfilter/nf_conntrack_proto_tcp.c Best regards, Jozsef - E-mail : kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.mta.hu PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Yes! I believe a piece of code that is machine dependent stole the packet and thereby got things messed up in conntrack. A rebuild seems to have taken care of the issue. Thanks for taking a look at this. The kernel version is 2.6.35. Again, thanks! On Thu, Oct 23, 2014 at 3:04 AM, Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> wrote: > On Wed, 22 Oct 2014, vDev wrote: > >> Thanks, Jozsef. Attached is the new packet capture and trace with patch >> applied. > > Thanks, now packets and conntrack states can be compared. > > Up to packet 6 everything is normal. However, look at packet 7: > > 16:20:21.653783 IP (tos 0x0, ttl 52, id 24152, offset 0, flags [DF], > proto TCP (6), length 40) > Remote_Server.63001 > Linux_Router.1039: Flags [F.], cksum 0x567b > (correct), seq 3661860393, ack 2561327135, win 14600, length 0 > > This is the first FIN packet, and the kernel debug log says: > > [ 376.950000] tcp_packet: > [ 376.950000] dir=1, seq=3661860393 ack=2561327135 win=14600 end=3661860394 > [ 376.950000] tcp_conntracks: > [ 376.950000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 > > The previous conntrack state is in "old=3", i.e. > TCP_CONNTRACK_ESTABLISHED. The new=4 means TCP_CONNTRACK_FIN_WAIT. However > between > > [ 376.950000] tcp_packet: > [ 376.950000] dir=1, seq=3661860393 ack=2561327135 win=14600 end=3661860394 > > and > > [ 376.950000] tcp_conntracks: > [ 376.950000] syn=0 ack=1 fin=1 rst=0 old=3 new=4 > > there is a missing the call to tcp_in_window()! Therefore the internal > counters of conntrack is not updated and later packets won't match the > wrong internal states. > > Why the call to tcp_in_window() is missing? Looking at tcp_packet(), > there's nothing which could cause skipping it: the big switch about the > new_state does not divert the handling of TCP_CONNTRACK_FIN_WAIT. > > So, what's your kernel version number? You have got the source: > please post net/netfilter/nf_conntrack_proto_tcp.c > > Best regards, > Jozsef > - > E-mail : kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.mta.hu > PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt > Address : Wigner Research Centre for Physics, Hungarian Academy of Sciences > H-1525 Budapest 114, POB. 49, Hungary -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 44d1ea3..655170f 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -830,12 +830,16 @@ static int tcp_packet(struct nf_conn *ct, th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); BUG_ON(th == NULL); + pr_debug("tcp_packet: "); spin_lock_bh(&ct->lock); old_state = ct->proto.tcp.state; dir = CTINFO2DIR(ctinfo); index = get_conntrack_index(th); new_state = tcp_conntracks[dir][index][old_state]; tuple = &ct->tuplehash[dir].tuple; + pr_debug("dir=%u, seq=%u ack=%u win=%u end=%u\n", + dir, ntohl(th->seq), ntohl(th->ack_seq), ntohs(th->window), + segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th)); switch (new_state) { case TCP_CONNTRACK_SYN_SENT: