diff options
| -rw-r--r-- | include/linux/netfilter/nf_conntrack_tcp.h | 3 | ||||
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 98 |
2 files changed, 63 insertions, 38 deletions
diff --git a/include/linux/netfilter/nf_conntrack_tcp.h b/include/linux/netfilter/nf_conntrack_tcp.h index 3066789b972a..74c27ca770e5 100644 --- a/include/linux/netfilter/nf_conntrack_tcp.h +++ b/include/linux/netfilter/nf_conntrack_tcp.h @@ -15,7 +15,8 @@ enum tcp_conntrack { TCP_CONNTRACK_LAST_ACK, TCP_CONNTRACK_TIME_WAIT, TCP_CONNTRACK_CLOSE, - TCP_CONNTRACK_LISTEN, + TCP_CONNTRACK_LISTEN, /* obsolete */ +#define TCP_CONNTRACK_SYN_SENT2 TCP_CONNTRACK_LISTEN TCP_CONNTRACK_MAX, TCP_CONNTRACK_IGNORE }; diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index b5ccf2b4b2e7..4c7f6f0dae90 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -59,7 +59,7 @@ static const char *const tcp_conntrack_names[] = { "LAST_ACK", "TIME_WAIT", "CLOSE", - "LISTEN" + "SYN_SENT2", }; #define SECS * HZ @@ -82,6 +82,7 @@ static unsigned int tcp_timeouts[TCP_CONNTRACK_MAX] __read_mostly = { [TCP_CONNTRACK_LAST_ACK] = 30 SECS, [TCP_CONNTRACK_TIME_WAIT] = 2 MINS, [TCP_CONNTRACK_CLOSE] = 10 SECS, + [TCP_CONNTRACK_SYN_SENT2] = 2 MINS, }; #define sNO TCP_CONNTRACK_NONE @@ -93,7 +94,7 @@ static unsigned int tcp_timeouts[TCP_CONNTRACK_MAX] __read_mostly = { #define sLA TCP_CONNTRACK_LAST_ACK #define sTW TCP_CONNTRACK_TIME_WAIT #define sCL TCP_CONNTRACK_CLOSE -#define sLI TCP_CONNTRACK_LISTEN +#define sS2 TCP_CONNTRACK_SYN_SENT2 #define sIV TCP_CONNTRACK_MAX #define sIG TCP_CONNTRACK_IGNORE @@ -123,6 +124,7 @@ enum tcp_bit_set { * * NONE: initial state * SYN_SENT: SYN-only packet seen + * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open * SYN_RECV: SYN-ACK packet seen * ESTABLISHED: ACK packet seen * FIN_WAIT: FIN packet seen @@ -131,26 +133,24 @@ enum tcp_bit_set { * TIME_WAIT: last ACK seen * CLOSE: closed connection (RST) * - * LISTEN state is not used. - * * Packets marked as IGNORED (sIG): * if they may be either invalid or valid * and the receiver may send back a connection * closing RST or a SYN/ACK. * * Packets marked as INVALID (sIV): - * if they are invalid - * or we do not support the request (simultaneous open) + * if we regard them as truly invalid packets */ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { { /* ORIGINAL */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 }, /* * sNO -> sSS Initialize a new connection * sSS -> sSS Retransmitted SYN - * sSR -> sIG Late retransmitted SYN? + * sS2 -> sS2 Late retransmitted SYN + * sSR -> sIG * sES -> sIG Error: SYNs in window outside the SYN_SENT state * are errors. Receiver will reply with RST * and close the connection. @@ -161,22 +161,30 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sSS Reopened connection (RFC 1122). * sCL -> sSS */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*synack*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*synack*/ { sIV, sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, /* - * A SYN/ACK from the client is always invalid: - * - either it tries to set up a simultaneous open, which is - * not supported; - * - or the firewall has just been inserted between the two hosts - * during the session set-up. The SYN will be retransmitted - * by the true client (or it'll time out). + * sNO -> sIV Too late and no reason to do anything + * sSS -> sIV Client can't send SYN and then SYN/ACK + * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open + * sSR -> sIG + * sES -> sIG Error: SYNs in window outside the SYN_SENT state + * are errors. Receiver will reply with RST + * and close the connection. + * Or we are not in sync and hold a dead connection. + * sFW -> sIG + * sCW -> sIG + * sLA -> sIG + * sTW -> sIG + * sCL -> sIG */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, /* * sNO -> sIV Too late and no reason to do anything... * sSS -> sIV Client migth not send FIN in this state: * we enforce waiting for a SYN/ACK reply first. + * sS2 -> sIV * sSR -> sFW Close started. * sES -> sFW * sFW -> sLA FIN seen in both directions, waiting for @@ -187,11 +195,12 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sTW * sCL -> sCL */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV }, /* * sNO -> sES Assumed. * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet. + * sS2 -> sIV * sSR -> sES Established state is reached. * sES -> sES :-) * sFW -> sCW Normal close request answered by ACK. @@ -200,29 +209,31 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sTW Retransmitted last ACK. Remain in the same state. * sCL -> sCL */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } }, { /* REPLY */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*syn*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sS2 }, /* * sNO -> sIV Never reached. - * sSS -> sIV Simultaneous open, not supported - * sSR -> sIV Simultaneous open, not supported. - * sES -> sIV Server may not initiate a connection. + * sSS -> sS2 Simultaneous open + * sS2 -> sS2 Retransmitted simultaneous SYN + * sSR -> sIV Invalid SYN packets sent by the server + * sES -> sIV * sFW -> sIV * sCW -> sIV * sLA -> sIV * sTW -> sIV Reopened connection, but server may not do it. * sCL -> sIV */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*synack*/ { sIV, sSR, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, /* * sSS -> sSR Standard open. + * sS2 -> sSR Simultaneous open * sSR -> sSR Retransmitted SYN/ACK. * sES -> sIG Late retransmitted SYN/ACK? * sFW -> sIG Might be SYN/ACK answering ignored SYN @@ -231,10 +242,11 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sIG * sCL -> sIG */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, /* * sSS -> sIV Server might not send FIN in this state. + * sS2 -> sIV * sSR -> sFW Close started. * sES -> sFW * sFW -> sLA FIN seen in both directions. @@ -243,10 +255,11 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sTW * sCL -> sCL */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG }, /* * sSS -> sIG Might be a half-open connection. + * sS2 -> sIG * sSR -> sSR Might answer late resent SYN. * sES -> sES :-) * sFW -> sCW Normal close request answered by ACK. @@ -255,8 +268,8 @@ static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { * sTW -> sTW Retransmitted last ACK. * sCL -> sCL */ -/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sLI */ -/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV }, +/* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ +/*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } } }; @@ -521,13 +534,14 @@ static bool tcp_in_window(const struct nf_conn *ct, receiver->td_end, receiver->td_maxend, receiver->td_maxwin, receiver->td_scale); - if (sender->td_end == 0) { + if (sender->td_maxwin == 0) { /* * Initialize sender data. */ - if (tcph->syn && tcph->ack) { + if (tcph->syn) { /* - * Outgoing SYN-ACK in reply to a SYN. + * SYN-ACK in reply to a SYN + * or SYN from reply direction in simultaneous open. */ sender->td_end = sender->td_maxend = end; @@ -543,6 +557,9 @@ static bool tcp_in_window(const struct nf_conn *ct, && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) sender->td_scale = receiver->td_scale = 0; + if (!tcph->ack) + /* Simultaneous open */ + return true; } else { /* * We are in the middle of a connection, @@ -1068,7 +1085,7 @@ static bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, ct->proto.tcp.seen[1].td_end = 0; ct->proto.tcp.seen[1].td_maxend = 0; - ct->proto.tcp.seen[1].td_maxwin = 1; + ct->proto.tcp.seen[1].td_maxwin = 0; ct->proto.tcp.seen[1].td_scale = 0; /* tcp_packet will set them */ @@ -1310,6 +1327,13 @@ static struct ctl_table tcp_compat_sysctl_table[] = { .proc_handler = proc_dointvec_jiffies, }, { + .procname = "ip_conntrack_tcp_timeout_syn_sent2", + .data = &tcp_timeouts[TCP_CONNTRACK_SYN_SENT2], + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { .procname = "ip_conntrack_tcp_timeout_syn_recv", .data = &tcp_timeouts[TCP_CONNTRACK_SYN_RECV], .maxlen = sizeof(unsigned int), |