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  1. Jun 08, 2009
    • Jan Kasprzak's avatar
      netfilter: nf_ct_icmp: keep the ICMP ct entries longer · f87fb666
      Jan Kasprzak authored
      
      
      Current conntrack code kills the ICMP conntrack entry as soon as
      the first reply is received. This is incorrect, as we then see only
      the first ICMP echo reply out of several possible duplicates as
      ESTABLISHED, while the rest will be INVALID. Also this unnecessarily
      increases the conntrackd traffic on H-A firewalls.
      
      Make all the ICMP conntrack entries (including the replied ones)
      last for the default of nf_conntrack_icmp{,v6}_timeout seconds.
      
      Signed-off-by: default avatarJan "Yenya" Kasprzak <kas@fi.muni.cz>
      Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
      f87fb666
  2. Jun 05, 2009
  3. Jun 04, 2009
  4. Jun 03, 2009
  5. Jun 02, 2009
    • Jozsef Kadlecsik's avatar
      netfilter: nf_ct_tcp: TCP simultaneous open support · 874ab923
      Jozsef Kadlecsik authored
      
      
      The patch below adds supporting TCP simultaneous open to conntrack. The
      unused LISTEN state is replaced by a new state (SYN_SENT2) denoting the
      second SYN sent from the reply direction in the new case. The state table
      is updated and the function tcp_in_window is modified to handle
      simultaneous open.
      
      The functionality can fairly easily be tested by socat. A sample tcpdump
      recording
      
      23:21:34.244733 IP (tos 0x0, ttl 64, id 49224, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.254.2020 > 192.168.0.1.2020: S, cksum 0xe75f (correct), 3383710133:3383710133(0) win 5840 <mss 1460,sackOK,timestamp 173445629 0,nop,wscale 7>
      23:21:34.244783 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.0.1.2020 > 192.168.0.254.2020: R, cksum 0x0253 (correct), 0:0(0) ack 3383710134 win 0
      23:21:36.038680 IP (tos 0x0, ttl 64, id 28092, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.1.2020 > 192.168.0.254.2020: S, cksum 0x704b (correct), 2634546729:2634546729(0) win 5840 <mss 1460,sackOK,timestamp 824213 0,nop,wscale 1>
      23:21:36.038777 IP (tos 0x0, ttl 64, id 49225, offset 0, flags [DF], proto TCP (6), length 60) 192.168.0.254.2020 > 192.168.0.1.2020: S, cksum 0xb179 (correct), 3383710133:3383710133(0) ack 2634546730 win 5840 <mss 1460,sackOK,timestamp 173447423 824213,nop,wscale 7>
      23:21:36.038847 IP (tos 0x0, ttl 64, id 28093, offset 0, flags [DF], proto TCP (6), length 52) 192.168.0.1.2020 > 192.168.0.254.2020: ., cksum 0xebad (correct), ack 3383710134 win 2920 <nop,nop,timestamp 824213 173447423>
      
      and the corresponding netlink events:
      
          [NEW] tcp      6 120 SYN_SENT src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 [UNREPLIED] src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
       [UPDATE] tcp      6 120 LISTEN src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
       [UPDATE] tcp      6 60 SYN_RECV src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020
       [UPDATE] tcp      6 432000 ESTABLISHED src=192.168.0.254 dst=192.168.0.1 sport=2020 dport=2020 src=192.168.0.1 dst=192.168.0.254 sport=2020 dport=2020 [ASSURED]
      
      The RST packet was dropped in the raw table, thus it did not reach
      conntrack.  nfnetlink_conntrack is unpatched so it shows the new SYN_SENT2
      state as the old unused LISTEN.
      
      With TCP simultaneous open support we satisfy REQ-2 in RFC 5382  ;-) .
      
      Additional minor correction in this patch is that in order to catch
      uninitialized reply directions, "td_maxwin == 0" is used instead of
      "td_end == 0" because the former can't be true except in uninitialized
      state while td_end may accidentally be equal to zero in the mid of a
      connection.
      
      Signed-off-by: default avatarJozsef Kadlecsik <kadlec@blackhole.kfki.hu>
      Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
      874ab923
    • Patrick McHardy's avatar
      8cc848fa
  6. May 27, 2009