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874ab9233e
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: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: Patrick McHardy <kaber@trash.net> |
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.. | ||
ipvs | ||
core.c | ||
Kconfig | ||
Makefile | ||
nf_conntrack_acct.c | ||
nf_conntrack_amanda.c | ||
nf_conntrack_core.c | ||
nf_conntrack_ecache.c | ||
nf_conntrack_expect.c | ||
nf_conntrack_extend.c | ||
nf_conntrack_ftp.c | ||
nf_conntrack_h323_asn1.c | ||
nf_conntrack_h323_main.c | ||
nf_conntrack_h323_types.c | ||
nf_conntrack_helper.c | ||
nf_conntrack_irc.c | ||
nf_conntrack_l3proto_generic.c | ||
nf_conntrack_netbios_ns.c | ||
nf_conntrack_netlink.c | ||
nf_conntrack_pptp.c | ||
nf_conntrack_proto.c | ||
nf_conntrack_proto_dccp.c | ||
nf_conntrack_proto_generic.c | ||
nf_conntrack_proto_gre.c | ||
nf_conntrack_proto_sctp.c | ||
nf_conntrack_proto_tcp.c | ||
nf_conntrack_proto_udp.c | ||
nf_conntrack_proto_udplite.c | ||
nf_conntrack_sane.c | ||
nf_conntrack_sip.c | ||
nf_conntrack_standalone.c | ||
nf_conntrack_tftp.c | ||
nf_internals.h | ||
nf_log.c | ||
nf_queue.c | ||
nf_sockopt.c | ||
nf_tproxy_core.c | ||
nfnetlink.c | ||
nfnetlink_log.c | ||
nfnetlink_queue.c | ||
x_tables.c | ||
xt_CLASSIFY.c | ||
xt_cluster.c | ||
xt_comment.c | ||
xt_connbytes.c | ||
xt_connlimit.c | ||
xt_CONNMARK.c | ||
xt_connmark.c | ||
xt_CONNSECMARK.c | ||
xt_conntrack.c | ||
xt_dccp.c | ||
xt_dscp.c | ||
xt_DSCP.c | ||
xt_esp.c | ||
xt_hashlimit.c | ||
xt_helper.c | ||
xt_hl.c | ||
xt_HL.c | ||
xt_iprange.c | ||
xt_LED.c | ||
xt_length.c | ||
xt_limit.c | ||
xt_mac.c | ||
xt_mark.c | ||
xt_MARK.c | ||
xt_multiport.c | ||
xt_NFLOG.c | ||
xt_NFQUEUE.c | ||
xt_NOTRACK.c | ||
xt_owner.c | ||
xt_physdev.c | ||
xt_pkttype.c | ||
xt_policy.c | ||
xt_quota.c | ||
xt_RATEEST.c | ||
xt_rateest.c | ||
xt_realm.c | ||
xt_recent.c | ||
xt_sctp.c | ||
xt_SECMARK.c | ||
xt_socket.c | ||
xt_state.c | ||
xt_statistic.c | ||
xt_string.c | ||
xt_TCPMSS.c | ||
xt_tcpmss.c | ||
xt_TCPOPTSTRIP.c | ||
xt_tcpudp.c | ||
xt_time.c | ||
xt_TPROXY.c | ||
xt_TRACE.c | ||
xt_u32.c |