1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2002-2013 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
4 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/types.h>
12 #include <linux/timer.h>
13 #include <linux/module.h>
15 #include <linux/tcp.h>
16 #include <linux/spinlock.h>
17 #include <linux/skbuff.h>
18 #include <linux/ipv6.h>
19 #include <net/ip6_checksum.h>
20 #include <asm/unaligned.h>
24 #include <linux/netfilter.h>
25 #include <linux/netfilter_ipv4.h>
26 #include <linux/netfilter_ipv6.h>
27 #include <net/netfilter/nf_conntrack.h>
28 #include <net/netfilter/nf_conntrack_l4proto.h>
29 #include <net/netfilter/nf_conntrack_ecache.h>
30 #include <net/netfilter/nf_conntrack_seqadj.h>
31 #include <net/netfilter/nf_conntrack_synproxy.h>
32 #include <net/netfilter/nf_log.h>
33 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
34 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
36 /* "Be conservative in what you do,
37 be liberal in what you accept from others."
38 If it's non-zero, we mark only out of window RST segments as INVALID. */
39 static int nf_ct_tcp_be_liberal __read_mostly
= 0;
41 /* If it is set to zero, we disable picking up already established
43 static int nf_ct_tcp_loose __read_mostly
= 1;
45 /* Max number of the retransmitted packets without receiving an (acceptable)
46 ACK from the destination. If this number is reached, a shorter timer
48 static int nf_ct_tcp_max_retrans __read_mostly
= 3;
50 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
51 closely. They're more complex. --RR */
53 static const char *const tcp_conntrack_names
[] = {
67 #define MINS * 60 SECS
68 #define HOURS * 60 MINS
69 #define DAYS * 24 HOURS
71 static unsigned int tcp_timeouts
[TCP_CONNTRACK_TIMEOUT_MAX
] __read_mostly
= {
72 [TCP_CONNTRACK_SYN_SENT
] = 2 MINS
,
73 [TCP_CONNTRACK_SYN_RECV
] = 60 SECS
,
74 [TCP_CONNTRACK_ESTABLISHED
] = 5 DAYS
,
75 [TCP_CONNTRACK_FIN_WAIT
] = 2 MINS
,
76 [TCP_CONNTRACK_CLOSE_WAIT
] = 60 SECS
,
77 [TCP_CONNTRACK_LAST_ACK
] = 30 SECS
,
78 [TCP_CONNTRACK_TIME_WAIT
] = 2 MINS
,
79 [TCP_CONNTRACK_CLOSE
] = 10 SECS
,
80 [TCP_CONNTRACK_SYN_SENT2
] = 2 MINS
,
81 /* RFC1122 says the R2 limit should be at least 100 seconds.
82 Linux uses 15 packets as limit, which corresponds
83 to ~13-30min depending on RTO. */
84 [TCP_CONNTRACK_RETRANS
] = 5 MINS
,
85 [TCP_CONNTRACK_UNACK
] = 5 MINS
,
88 #define sNO TCP_CONNTRACK_NONE
89 #define sSS TCP_CONNTRACK_SYN_SENT
90 #define sSR TCP_CONNTRACK_SYN_RECV
91 #define sES TCP_CONNTRACK_ESTABLISHED
92 #define sFW TCP_CONNTRACK_FIN_WAIT
93 #define sCW TCP_CONNTRACK_CLOSE_WAIT
94 #define sLA TCP_CONNTRACK_LAST_ACK
95 #define sTW TCP_CONNTRACK_TIME_WAIT
96 #define sCL TCP_CONNTRACK_CLOSE
97 #define sS2 TCP_CONNTRACK_SYN_SENT2
98 #define sIV TCP_CONNTRACK_MAX
99 #define sIG TCP_CONNTRACK_IGNORE
101 /* What TCP flags are set from RST/SYN/FIN/ACK. */
112 * The TCP state transition table needs a few words...
114 * We are the man in the middle. All the packets go through us
115 * but might get lost in transit to the destination.
116 * It is assumed that the destinations can't receive segments
119 * The checked segment is in window, but our windows are *not*
120 * equivalent with the ones of the sender/receiver. We always
121 * try to guess the state of the current sender.
123 * The meaning of the states are:
125 * NONE: initial state
126 * SYN_SENT: SYN-only packet seen
127 * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open
128 * SYN_RECV: SYN-ACK packet seen
129 * ESTABLISHED: ACK packet seen
130 * FIN_WAIT: FIN packet seen
131 * CLOSE_WAIT: ACK seen (after FIN)
132 * LAST_ACK: FIN seen (after FIN)
133 * TIME_WAIT: last ACK seen
134 * CLOSE: closed connection (RST)
136 * Packets marked as IGNORED (sIG):
137 * if they may be either invalid or valid
138 * and the receiver may send back a connection
139 * closing RST or a SYN/ACK.
141 * Packets marked as INVALID (sIV):
142 * if we regard them as truly invalid packets
144 static const u8 tcp_conntracks
[2][6][TCP_CONNTRACK_MAX
] = {
147 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
148 /*syn*/ { sSS
, sSS
, sIG
, sIG
, sIG
, sIG
, sIG
, sSS
, sSS
, sS2
},
150 * sNO -> sSS Initialize a new connection
151 * sSS -> sSS Retransmitted SYN
152 * sS2 -> sS2 Late retransmitted SYN
154 * sES -> sIG Error: SYNs in window outside the SYN_SENT state
155 * are errors. Receiver will reply with RST
156 * and close the connection.
157 * Or we are not in sync and hold a dead connection.
161 * sTW -> sSS Reopened connection (RFC 1122).
164 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
165 /*synack*/ { sIV
, sIV
, sSR
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sSR
},
167 * sNO -> sIV Too late and no reason to do anything
168 * sSS -> sIV Client can't send SYN and then SYN/ACK
169 * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open
170 * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open
171 * sES -> sIV Invalid SYN/ACK packets sent by the client
178 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
179 /*fin*/ { sIV
, sIV
, sFW
, sFW
, sLA
, sLA
, sLA
, sTW
, sCL
, sIV
},
181 * sNO -> sIV Too late and no reason to do anything...
182 * sSS -> sIV Client migth not send FIN in this state:
183 * we enforce waiting for a SYN/ACK reply first.
185 * sSR -> sFW Close started.
187 * sFW -> sLA FIN seen in both directions, waiting for
189 * Migth be a retransmitted FIN as well...
191 * sLA -> sLA Retransmitted FIN. Remain in the same state.
195 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
196 /*ack*/ { sES
, sIV
, sES
, sES
, sCW
, sCW
, sTW
, sTW
, sCL
, sIV
},
198 * sNO -> sES Assumed.
199 * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet.
201 * sSR -> sES Established state is reached.
203 * sFW -> sCW Normal close request answered by ACK.
205 * sLA -> sTW Last ACK detected (RFC5961 challenged)
206 * sTW -> sTW Retransmitted last ACK. Remain in the same state.
209 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
210 /*rst*/ { sIV
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
},
211 /*none*/ { sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
}
215 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
216 /*syn*/ { sIV
, sS2
, sIV
, sIV
, sIV
, sIV
, sIV
, sSS
, sIV
, sS2
},
218 * sNO -> sIV Never reached.
219 * sSS -> sS2 Simultaneous open
220 * sS2 -> sS2 Retransmitted simultaneous SYN
221 * sSR -> sIV Invalid SYN packets sent by the server
226 * sTW -> sSS Reopened connection, but server may have switched role
229 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
230 /*synack*/ { sIV
, sSR
, sIG
, sIG
, sIG
, sIG
, sIG
, sIG
, sIG
, sSR
},
232 * sSS -> sSR Standard open.
233 * sS2 -> sSR Simultaneous open
234 * sSR -> sIG Retransmitted SYN/ACK, ignore it.
235 * sES -> sIG Late retransmitted SYN/ACK?
236 * sFW -> sIG Might be SYN/ACK answering ignored SYN
242 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
243 /*fin*/ { sIV
, sIV
, sFW
, sFW
, sLA
, sLA
, sLA
, sTW
, sCL
, sIV
},
245 * sSS -> sIV Server might not send FIN in this state.
247 * sSR -> sFW Close started.
249 * sFW -> sLA FIN seen in both directions.
251 * sLA -> sLA Retransmitted FIN.
255 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
256 /*ack*/ { sIV
, sIG
, sSR
, sES
, sCW
, sCW
, sTW
, sTW
, sCL
, sIG
},
258 * sSS -> sIG Might be a half-open connection.
260 * sSR -> sSR Might answer late resent SYN.
262 * sFW -> sCW Normal close request answered by ACK.
264 * sLA -> sTW Last ACK detected (RFC5961 challenged)
265 * sTW -> sTW Retransmitted last ACK.
268 /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */
269 /*rst*/ { sIV
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
, sCL
},
270 /*none*/ { sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
, sIV
}
274 static inline struct nf_tcp_net
*tcp_pernet(struct net
*net
)
276 return &net
->ct
.nf_ct_proto
.tcp
;
279 static bool tcp_pkt_to_tuple(const struct sk_buff
*skb
, unsigned int dataoff
,
280 struct net
*net
, struct nf_conntrack_tuple
*tuple
)
282 const struct tcphdr
*hp
;
285 /* Actually only need first 4 bytes to get ports. */
286 hp
= skb_header_pointer(skb
, dataoff
, 4, &_hdr
);
290 tuple
->src
.u
.tcp
.port
= hp
->source
;
291 tuple
->dst
.u
.tcp
.port
= hp
->dest
;
296 static bool tcp_invert_tuple(struct nf_conntrack_tuple
*tuple
,
297 const struct nf_conntrack_tuple
*orig
)
299 tuple
->src
.u
.tcp
.port
= orig
->dst
.u
.tcp
.port
;
300 tuple
->dst
.u
.tcp
.port
= orig
->src
.u
.tcp
.port
;
304 /* Print out the per-protocol part of the tuple. */
305 static void tcp_print_tuple(struct seq_file
*s
,
306 const struct nf_conntrack_tuple
*tuple
)
308 seq_printf(s
, "sport=%hu dport=%hu ",
309 ntohs(tuple
->src
.u
.tcp
.port
),
310 ntohs(tuple
->dst
.u
.tcp
.port
));
313 /* Print out the private part of the conntrack. */
314 static void tcp_print_conntrack(struct seq_file
*s
, struct nf_conn
*ct
)
316 seq_printf(s
, "%s ", tcp_conntrack_names
[ct
->proto
.tcp
.state
]);
319 static unsigned int get_conntrack_index(const struct tcphdr
*tcph
)
321 if (tcph
->rst
) return TCP_RST_SET
;
322 else if (tcph
->syn
) return (tcph
->ack
? TCP_SYNACK_SET
: TCP_SYN_SET
);
323 else if (tcph
->fin
) return TCP_FIN_SET
;
324 else if (tcph
->ack
) return TCP_ACK_SET
;
325 else return TCP_NONE_SET
;
328 /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering
329 in IP Filter' by Guido van Rooij.
331 http://www.sane.nl/events/sane2000/papers.html
332 http://www.darkart.com/mirrors/www.obfuscation.org/ipf/
334 The boundaries and the conditions are changed according to RFC793:
335 the packet must intersect the window (i.e. segments may be
336 after the right or before the left edge) and thus receivers may ACK
337 segments after the right edge of the window.
339 td_maxend = max(sack + max(win,1)) seen in reply packets
340 td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets
341 td_maxwin += seq + len - sender.td_maxend
342 if seq + len > sender.td_maxend
343 td_end = max(seq + len) seen in sent packets
345 I. Upper bound for valid data: seq <= sender.td_maxend
346 II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin
347 III. Upper bound for valid (s)ack: sack <= receiver.td_end
348 IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW
350 where sack is the highest right edge of sack block found in the packet
351 or ack in the case of packet without SACK option.
353 The upper bound limit for a valid (s)ack is not ignored -
354 we doesn't have to deal with fragments.
357 static inline __u32
segment_seq_plus_len(__u32 seq
,
359 unsigned int dataoff
,
360 const struct tcphdr
*tcph
)
362 /* XXX Should I use payload length field in IP/IPv6 header ?
364 return (seq
+ len
- dataoff
- tcph
->doff
*4
365 + (tcph
->syn
? 1 : 0) + (tcph
->fin
? 1 : 0));
368 /* Fixme: what about big packets? */
369 #define MAXACKWINCONST 66000
370 #define MAXACKWINDOW(sender) \
371 ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \
375 * Simplified tcp_parse_options routine from tcp_input.c
377 static void tcp_options(const struct sk_buff
*skb
,
378 unsigned int dataoff
,
379 const struct tcphdr
*tcph
,
380 struct ip_ct_tcp_state
*state
)
382 unsigned char buff
[(15 * 4) - sizeof(struct tcphdr
)];
383 const unsigned char *ptr
;
384 int length
= (tcph
->doff
*4) - sizeof(struct tcphdr
);
389 ptr
= skb_header_pointer(skb
, dataoff
+ sizeof(struct tcphdr
),
403 case TCPOPT_NOP
: /* Ref: RFC 793 section 3.1 */
410 if (opsize
< 2) /* "silly options" */
413 return; /* don't parse partial options */
415 if (opcode
== TCPOPT_SACK_PERM
416 && opsize
== TCPOLEN_SACK_PERM
)
417 state
->flags
|= IP_CT_TCP_FLAG_SACK_PERM
;
418 else if (opcode
== TCPOPT_WINDOW
419 && opsize
== TCPOLEN_WINDOW
) {
420 state
->td_scale
= *(u_int8_t
*)ptr
;
422 if (state
->td_scale
> 14) {
424 state
->td_scale
= 14;
427 IP_CT_TCP_FLAG_WINDOW_SCALE
;
435 static void tcp_sack(const struct sk_buff
*skb
, unsigned int dataoff
,
436 const struct tcphdr
*tcph
, __u32
*sack
)
438 unsigned char buff
[(15 * 4) - sizeof(struct tcphdr
)];
439 const unsigned char *ptr
;
440 int length
= (tcph
->doff
*4) - sizeof(struct tcphdr
);
446 ptr
= skb_header_pointer(skb
, dataoff
+ sizeof(struct tcphdr
),
450 /* Fast path for timestamp-only option */
451 if (length
== TCPOLEN_TSTAMP_ALIGNED
452 && *(__be32
*)ptr
== htonl((TCPOPT_NOP
<< 24)
454 | (TCPOPT_TIMESTAMP
<< 8)
455 | TCPOLEN_TIMESTAMP
))
465 case TCPOPT_NOP
: /* Ref: RFC 793 section 3.1 */
472 if (opsize
< 2) /* "silly options" */
475 return; /* don't parse partial options */
477 if (opcode
== TCPOPT_SACK
478 && opsize
>= (TCPOLEN_SACK_BASE
479 + TCPOLEN_SACK_PERBLOCK
)
480 && !((opsize
- TCPOLEN_SACK_BASE
)
481 % TCPOLEN_SACK_PERBLOCK
)) {
483 i
< (opsize
- TCPOLEN_SACK_BASE
);
484 i
+= TCPOLEN_SACK_PERBLOCK
) {
485 tmp
= get_unaligned_be32((__be32
*)(ptr
+i
)+1);
487 if (after(tmp
, *sack
))
498 static bool tcp_in_window(const struct nf_conn
*ct
,
499 struct ip_ct_tcp
*state
,
500 enum ip_conntrack_dir dir
,
502 const struct sk_buff
*skb
,
503 unsigned int dataoff
,
504 const struct tcphdr
*tcph
,
507 struct net
*net
= nf_ct_net(ct
);
508 struct nf_tcp_net
*tn
= tcp_pernet(net
);
509 struct ip_ct_tcp_state
*sender
= &state
->seen
[dir
];
510 struct ip_ct_tcp_state
*receiver
= &state
->seen
[!dir
];
511 const struct nf_conntrack_tuple
*tuple
= &ct
->tuplehash
[dir
].tuple
;
512 __u32 seq
, ack
, sack
, end
, win
, swin
;
514 bool res
, in_recv_win
;
517 * Get the required data from the packet.
519 seq
= ntohl(tcph
->seq
);
520 ack
= sack
= ntohl(tcph
->ack_seq
);
521 win
= ntohs(tcph
->window
);
522 end
= segment_seq_plus_len(seq
, skb
->len
, dataoff
, tcph
);
524 if (receiver
->flags
& IP_CT_TCP_FLAG_SACK_PERM
)
525 tcp_sack(skb
, dataoff
, tcph
, &sack
);
527 /* Take into account NAT sequence number mangling */
528 receiver_offset
= nf_ct_seq_offset(ct
, !dir
, ack
- 1);
529 ack
-= receiver_offset
;
530 sack
-= receiver_offset
;
532 pr_debug("tcp_in_window: START\n");
533 pr_debug("tcp_in_window: ");
534 nf_ct_dump_tuple(tuple
);
535 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
536 seq
, ack
, receiver_offset
, sack
, receiver_offset
, win
, end
);
537 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
538 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
539 sender
->td_end
, sender
->td_maxend
, sender
->td_maxwin
,
541 receiver
->td_end
, receiver
->td_maxend
, receiver
->td_maxwin
,
544 if (sender
->td_maxwin
== 0) {
546 * Initialize sender data.
550 * SYN-ACK in reply to a SYN
551 * or SYN from reply direction in simultaneous open.
554 sender
->td_maxend
= end
;
555 sender
->td_maxwin
= (win
== 0 ? 1 : win
);
557 tcp_options(skb
, dataoff
, tcph
, sender
);
560 * Both sides must send the Window Scale option
561 * to enable window scaling in either direction.
563 if (!(sender
->flags
& IP_CT_TCP_FLAG_WINDOW_SCALE
564 && receiver
->flags
& IP_CT_TCP_FLAG_WINDOW_SCALE
))
566 receiver
->td_scale
= 0;
568 /* Simultaneous open */
572 * We are in the middle of a connection,
573 * its history is lost for us.
574 * Let's try to use the data from the packet.
576 sender
->td_end
= end
;
577 swin
= win
<< sender
->td_scale
;
578 sender
->td_maxwin
= (swin
== 0 ? 1 : swin
);
579 sender
->td_maxend
= end
+ sender
->td_maxwin
;
581 * We haven't seen traffic in the other direction yet
582 * but we have to tweak window tracking to pass III
583 * and IV until that happens.
585 if (receiver
->td_maxwin
== 0)
586 receiver
->td_end
= receiver
->td_maxend
= sack
;
588 } else if (((state
->state
== TCP_CONNTRACK_SYN_SENT
589 && dir
== IP_CT_DIR_ORIGINAL
)
590 || (state
->state
== TCP_CONNTRACK_SYN_RECV
591 && dir
== IP_CT_DIR_REPLY
))
592 && after(end
, sender
->td_end
)) {
594 * RFC 793: "if a TCP is reinitialized ... then it need
595 * not wait at all; it must only be sure to use sequence
596 * numbers larger than those recently used."
599 sender
->td_maxend
= end
;
600 sender
->td_maxwin
= (win
== 0 ? 1 : win
);
602 tcp_options(skb
, dataoff
, tcph
, sender
);
607 * If there is no ACK, just pretend it was set and OK.
609 ack
= sack
= receiver
->td_end
;
610 } else if (((tcp_flag_word(tcph
) & (TCP_FLAG_ACK
|TCP_FLAG_RST
)) ==
611 (TCP_FLAG_ACK
|TCP_FLAG_RST
))
614 * Broken TCP stacks, that set ACK in RST packets as well
615 * with zero ack value.
617 ack
= sack
= receiver
->td_end
;
620 if (tcph
->rst
&& seq
== 0 && state
->state
== TCP_CONNTRACK_SYN_SENT
)
622 * RST sent answering SYN.
624 seq
= end
= sender
->td_end
;
626 pr_debug("tcp_in_window: ");
627 nf_ct_dump_tuple(tuple
);
628 pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n",
629 seq
, ack
, receiver_offset
, sack
, receiver_offset
, win
, end
);
630 pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i "
631 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
632 sender
->td_end
, sender
->td_maxend
, sender
->td_maxwin
,
634 receiver
->td_end
, receiver
->td_maxend
, receiver
->td_maxwin
,
637 /* Is the ending sequence in the receive window (if available)? */
638 in_recv_win
= !receiver
->td_maxwin
||
639 after(end
, sender
->td_end
- receiver
->td_maxwin
- 1);
641 pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n",
642 before(seq
, sender
->td_maxend
+ 1),
643 (in_recv_win
? 1 : 0),
644 before(sack
, receiver
->td_end
+ 1),
645 after(sack
, receiver
->td_end
- MAXACKWINDOW(sender
) - 1));
647 if (before(seq
, sender
->td_maxend
+ 1) &&
649 before(sack
, receiver
->td_end
+ 1) &&
650 after(sack
, receiver
->td_end
- MAXACKWINDOW(sender
) - 1)) {
652 * Take into account window scaling (RFC 1323).
655 win
<<= sender
->td_scale
;
658 * Update sender data.
660 swin
= win
+ (sack
- ack
);
661 if (sender
->td_maxwin
< swin
)
662 sender
->td_maxwin
= swin
;
663 if (after(end
, sender
->td_end
)) {
664 sender
->td_end
= end
;
665 sender
->flags
|= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED
;
668 if (!(sender
->flags
& IP_CT_TCP_FLAG_MAXACK_SET
)) {
669 sender
->td_maxack
= ack
;
670 sender
->flags
|= IP_CT_TCP_FLAG_MAXACK_SET
;
671 } else if (after(ack
, sender
->td_maxack
))
672 sender
->td_maxack
= ack
;
676 * Update receiver data.
678 if (receiver
->td_maxwin
!= 0 && after(end
, sender
->td_maxend
))
679 receiver
->td_maxwin
+= end
- sender
->td_maxend
;
680 if (after(sack
+ win
, receiver
->td_maxend
- 1)) {
681 receiver
->td_maxend
= sack
+ win
;
683 receiver
->td_maxend
++;
685 if (ack
== receiver
->td_end
)
686 receiver
->flags
&= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED
;
689 * Check retransmissions.
691 if (index
== TCP_ACK_SET
) {
692 if (state
->last_dir
== dir
693 && state
->last_seq
== seq
694 && state
->last_ack
== ack
695 && state
->last_end
== end
696 && state
->last_win
== win
)
699 state
->last_dir
= dir
;
700 state
->last_seq
= seq
;
701 state
->last_ack
= ack
;
702 state
->last_end
= end
;
703 state
->last_win
= win
;
710 if (sender
->flags
& IP_CT_TCP_FLAG_BE_LIBERAL
||
713 if (!res
&& LOG_INVALID(net
, IPPROTO_TCP
))
714 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
716 before(seq
, sender
->td_maxend
+ 1) ?
718 before(sack
, receiver
->td_end
+ 1) ?
719 after(sack
, receiver
->td_end
- MAXACKWINDOW(sender
) - 1) ? "BUG"
720 : "ACK is under the lower bound (possible overly delayed ACK)"
721 : "ACK is over the upper bound (ACKed data not seen yet)"
722 : "SEQ is under the lower bound (already ACKed data retransmitted)"
723 : "SEQ is over the upper bound (over the window of the receiver)");
726 pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u "
727 "receiver end=%u maxend=%u maxwin=%u\n",
728 res
, sender
->td_end
, sender
->td_maxend
, sender
->td_maxwin
,
729 receiver
->td_end
, receiver
->td_maxend
, receiver
->td_maxwin
);
734 /* table of valid flag combinations - PUSH, ECE and CWR are always valid */
735 static const u8 tcp_valid_flags
[(TCPHDR_FIN
|TCPHDR_SYN
|TCPHDR_RST
|TCPHDR_ACK
|
739 [TCPHDR_SYN
|TCPHDR_URG
] = 1,
740 [TCPHDR_SYN
|TCPHDR_ACK
] = 1,
742 [TCPHDR_RST
|TCPHDR_ACK
] = 1,
743 [TCPHDR_FIN
|TCPHDR_ACK
] = 1,
744 [TCPHDR_FIN
|TCPHDR_ACK
|TCPHDR_URG
] = 1,
746 [TCPHDR_ACK
|TCPHDR_URG
] = 1,
749 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */
750 static int tcp_error(struct net
*net
, struct nf_conn
*tmpl
,
752 unsigned int dataoff
,
754 unsigned int hooknum
)
756 const struct tcphdr
*th
;
758 unsigned int tcplen
= skb
->len
- dataoff
;
761 /* Smaller that minimal TCP header? */
762 th
= skb_header_pointer(skb
, dataoff
, sizeof(_tcph
), &_tcph
);
764 if (LOG_INVALID(net
, IPPROTO_TCP
))
765 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
766 "nf_ct_tcp: short packet ");
770 /* Not whole TCP header or malformed packet */
771 if (th
->doff
*4 < sizeof(struct tcphdr
) || tcplen
< th
->doff
*4) {
772 if (LOG_INVALID(net
, IPPROTO_TCP
))
773 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
774 "nf_ct_tcp: truncated/malformed packet ");
778 /* Checksum invalid? Ignore.
779 * We skip checking packets on the outgoing path
780 * because the checksum is assumed to be correct.
782 /* FIXME: Source route IP option packets --RR */
783 if (net
->ct
.sysctl_checksum
&& hooknum
== NF_INET_PRE_ROUTING
&&
784 nf_checksum(skb
, hooknum
, dataoff
, IPPROTO_TCP
, pf
)) {
785 if (LOG_INVALID(net
, IPPROTO_TCP
))
786 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
787 "nf_ct_tcp: bad TCP checksum ");
791 /* Check TCP flags. */
792 tcpflags
= (tcp_flag_byte(th
) & ~(TCPHDR_ECE
|TCPHDR_CWR
|TCPHDR_PSH
));
793 if (!tcp_valid_flags
[tcpflags
]) {
794 if (LOG_INVALID(net
, IPPROTO_TCP
))
795 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
796 "nf_ct_tcp: invalid TCP flag combination ");
803 static unsigned int *tcp_get_timeouts(struct net
*net
)
805 return tcp_pernet(net
)->timeouts
;
808 /* Returns verdict for packet, or -1 for invalid. */
809 static int tcp_packet(struct nf_conn
*ct
,
810 const struct sk_buff
*skb
,
811 unsigned int dataoff
,
812 enum ip_conntrack_info ctinfo
,
814 unsigned int hooknum
,
815 unsigned int *timeouts
)
817 struct net
*net
= nf_ct_net(ct
);
818 struct nf_tcp_net
*tn
= tcp_pernet(net
);
819 struct nf_conntrack_tuple
*tuple
;
820 enum tcp_conntrack new_state
, old_state
;
821 enum ip_conntrack_dir dir
;
822 const struct tcphdr
*th
;
824 unsigned long timeout
;
827 th
= skb_header_pointer(skb
, dataoff
, sizeof(_tcph
), &_tcph
);
830 spin_lock_bh(&ct
->lock
);
831 old_state
= ct
->proto
.tcp
.state
;
832 dir
= CTINFO2DIR(ctinfo
);
833 index
= get_conntrack_index(th
);
834 new_state
= tcp_conntracks
[dir
][index
][old_state
];
835 tuple
= &ct
->tuplehash
[dir
].tuple
;
838 case TCP_CONNTRACK_SYN_SENT
:
839 if (old_state
< TCP_CONNTRACK_TIME_WAIT
)
841 /* RFC 1122: "When a connection is closed actively,
842 * it MUST linger in TIME-WAIT state for a time 2xMSL
843 * (Maximum Segment Lifetime). However, it MAY accept
844 * a new SYN from the remote TCP to reopen the connection
845 * directly from TIME-WAIT state, if..."
846 * We ignore the conditions because we are in the
847 * TIME-WAIT state anyway.
849 * Handle aborted connections: we and the server
850 * think there is an existing connection but the client
851 * aborts it and starts a new one.
853 if (((ct
->proto
.tcp
.seen
[dir
].flags
854 | ct
->proto
.tcp
.seen
[!dir
].flags
)
855 & IP_CT_TCP_FLAG_CLOSE_INIT
)
856 || (ct
->proto
.tcp
.last_dir
== dir
857 && ct
->proto
.tcp
.last_index
== TCP_RST_SET
)) {
858 /* Attempt to reopen a closed/aborted connection.
859 * Delete this connection and look up again. */
860 spin_unlock_bh(&ct
->lock
);
862 /* Only repeat if we can actually remove the timer.
863 * Destruction may already be in progress in process
864 * context and we must give it a chance to terminate.
871 case TCP_CONNTRACK_IGNORE
:
874 * Our connection entry may be out of sync, so ignore
875 * packets which may signal the real connection between
876 * the client and the server.
879 * b) SYN/ACK in REPLY
880 * c) ACK in reply direction after initial SYN in original.
882 * If the ignored packet is invalid, the receiver will send
883 * a RST we'll catch below.
885 if (index
== TCP_SYNACK_SET
886 && ct
->proto
.tcp
.last_index
== TCP_SYN_SET
887 && ct
->proto
.tcp
.last_dir
!= dir
888 && ntohl(th
->ack_seq
) == ct
->proto
.tcp
.last_end
) {
889 /* b) This SYN/ACK acknowledges a SYN that we earlier
890 * ignored as invalid. This means that the client and
891 * the server are both in sync, while the firewall is
892 * not. We get in sync from the previously annotated
895 old_state
= TCP_CONNTRACK_SYN_SENT
;
896 new_state
= TCP_CONNTRACK_SYN_RECV
;
897 ct
->proto
.tcp
.seen
[ct
->proto
.tcp
.last_dir
].td_end
=
898 ct
->proto
.tcp
.last_end
;
899 ct
->proto
.tcp
.seen
[ct
->proto
.tcp
.last_dir
].td_maxend
=
900 ct
->proto
.tcp
.last_end
;
901 ct
->proto
.tcp
.seen
[ct
->proto
.tcp
.last_dir
].td_maxwin
=
902 ct
->proto
.tcp
.last_win
== 0 ?
903 1 : ct
->proto
.tcp
.last_win
;
904 ct
->proto
.tcp
.seen
[ct
->proto
.tcp
.last_dir
].td_scale
=
905 ct
->proto
.tcp
.last_wscale
;
906 ct
->proto
.tcp
.last_flags
&= ~IP_CT_EXP_CHALLENGE_ACK
;
907 ct
->proto
.tcp
.seen
[ct
->proto
.tcp
.last_dir
].flags
=
908 ct
->proto
.tcp
.last_flags
;
909 memset(&ct
->proto
.tcp
.seen
[dir
], 0,
910 sizeof(struct ip_ct_tcp_state
));
913 ct
->proto
.tcp
.last_index
= index
;
914 ct
->proto
.tcp
.last_dir
= dir
;
915 ct
->proto
.tcp
.last_seq
= ntohl(th
->seq
);
916 ct
->proto
.tcp
.last_end
=
917 segment_seq_plus_len(ntohl(th
->seq
), skb
->len
, dataoff
, th
);
918 ct
->proto
.tcp
.last_win
= ntohs(th
->window
);
920 /* a) This is a SYN in ORIGINAL. The client and the server
921 * may be in sync but we are not. In that case, we annotate
922 * the TCP options and let the packet go through. If it is a
923 * valid SYN packet, the server will reply with a SYN/ACK, and
924 * then we'll get in sync. Otherwise, the server potentially
925 * responds with a challenge ACK if implementing RFC5961.
927 if (index
== TCP_SYN_SET
&& dir
== IP_CT_DIR_ORIGINAL
) {
928 struct ip_ct_tcp_state seen
= {};
930 ct
->proto
.tcp
.last_flags
=
931 ct
->proto
.tcp
.last_wscale
= 0;
932 tcp_options(skb
, dataoff
, th
, &seen
);
933 if (seen
.flags
& IP_CT_TCP_FLAG_WINDOW_SCALE
) {
934 ct
->proto
.tcp
.last_flags
|=
935 IP_CT_TCP_FLAG_WINDOW_SCALE
;
936 ct
->proto
.tcp
.last_wscale
= seen
.td_scale
;
938 if (seen
.flags
& IP_CT_TCP_FLAG_SACK_PERM
) {
939 ct
->proto
.tcp
.last_flags
|=
940 IP_CT_TCP_FLAG_SACK_PERM
;
942 /* Mark the potential for RFC5961 challenge ACK,
943 * this pose a special problem for LAST_ACK state
944 * as ACK is intrepretated as ACKing last FIN.
946 if (old_state
== TCP_CONNTRACK_LAST_ACK
)
947 ct
->proto
.tcp
.last_flags
|=
948 IP_CT_EXP_CHALLENGE_ACK
;
950 spin_unlock_bh(&ct
->lock
);
951 if (LOG_INVALID(net
, IPPROTO_TCP
))
952 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
953 "nf_ct_tcp: invalid packet ignored in "
954 "state %s ", tcp_conntrack_names
[old_state
]);
956 case TCP_CONNTRACK_MAX
:
957 /* Special case for SYN proxy: when the SYN to the server or
958 * the SYN/ACK from the server is lost, the client may transmit
959 * a keep-alive packet while in SYN_SENT state. This needs to
960 * be associated with the original conntrack entry in order to
961 * generate a new SYN with the correct sequence number.
963 if (nfct_synproxy(ct
) && old_state
== TCP_CONNTRACK_SYN_SENT
&&
964 index
== TCP_ACK_SET
&& dir
== IP_CT_DIR_ORIGINAL
&&
965 ct
->proto
.tcp
.last_dir
== IP_CT_DIR_ORIGINAL
&&
966 ct
->proto
.tcp
.seen
[dir
].td_end
- 1 == ntohl(th
->seq
)) {
967 pr_debug("nf_ct_tcp: SYN proxy client keep alive\n");
968 spin_unlock_bh(&ct
->lock
);
973 pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n",
974 dir
, get_conntrack_index(th
), old_state
);
975 spin_unlock_bh(&ct
->lock
);
976 if (LOG_INVALID(net
, IPPROTO_TCP
))
977 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
978 "nf_ct_tcp: invalid state ");
980 case TCP_CONNTRACK_TIME_WAIT
:
981 /* RFC5961 compliance cause stack to send "challenge-ACK"
982 * e.g. in response to spurious SYNs. Conntrack MUST
983 * not believe this ACK is acking last FIN.
985 if (old_state
== TCP_CONNTRACK_LAST_ACK
&&
986 index
== TCP_ACK_SET
&&
987 ct
->proto
.tcp
.last_dir
!= dir
&&
988 ct
->proto
.tcp
.last_index
== TCP_SYN_SET
&&
989 (ct
->proto
.tcp
.last_flags
& IP_CT_EXP_CHALLENGE_ACK
)) {
990 /* Detected RFC5961 challenge ACK */
991 ct
->proto
.tcp
.last_flags
&= ~IP_CT_EXP_CHALLENGE_ACK
;
992 spin_unlock_bh(&ct
->lock
);
993 if (LOG_INVALID(net
, IPPROTO_TCP
))
994 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
, NULL
,
995 "nf_ct_tcp: challenge-ACK ignored ");
996 return NF_ACCEPT
; /* Don't change state */
999 case TCP_CONNTRACK_CLOSE
:
1000 if (index
== TCP_RST_SET
1001 && (ct
->proto
.tcp
.seen
[!dir
].flags
& IP_CT_TCP_FLAG_MAXACK_SET
)
1002 && before(ntohl(th
->seq
), ct
->proto
.tcp
.seen
[!dir
].td_maxack
)) {
1004 spin_unlock_bh(&ct
->lock
);
1005 if (LOG_INVALID(net
, IPPROTO_TCP
))
1006 nf_log_packet(net
, pf
, 0, skb
, NULL
, NULL
,
1007 NULL
, "nf_ct_tcp: invalid RST ");
1010 if (index
== TCP_RST_SET
1011 && ((test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)
1012 && ct
->proto
.tcp
.last_index
== TCP_SYN_SET
)
1013 || (!test_bit(IPS_ASSURED_BIT
, &ct
->status
)
1014 && ct
->proto
.tcp
.last_index
== TCP_ACK_SET
))
1015 && ntohl(th
->ack_seq
) == ct
->proto
.tcp
.last_end
) {
1016 /* RST sent to invalid SYN or ACK we had let through
1017 * at a) and c) above:
1019 * a) SYN was in window then
1020 * c) we hold a half-open connection.
1022 * Delete our connection entry.
1023 * We skip window checking, because packet might ACK
1024 * segments we ignored. */
1027 /* Just fall through */
1029 /* Keep compilers happy. */
1033 if (!tcp_in_window(ct
, &ct
->proto
.tcp
, dir
, index
,
1034 skb
, dataoff
, th
, pf
)) {
1035 spin_unlock_bh(&ct
->lock
);
1039 /* From now on we have got in-window packets */
1040 ct
->proto
.tcp
.last_index
= index
;
1041 ct
->proto
.tcp
.last_dir
= dir
;
1043 pr_debug("tcp_conntracks: ");
1044 nf_ct_dump_tuple(tuple
);
1045 pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n",
1046 (th
->syn
? 1 : 0), (th
->ack
? 1 : 0),
1047 (th
->fin
? 1 : 0), (th
->rst
? 1 : 0),
1048 old_state
, new_state
);
1050 ct
->proto
.tcp
.state
= new_state
;
1051 if (old_state
!= new_state
1052 && new_state
== TCP_CONNTRACK_FIN_WAIT
)
1053 ct
->proto
.tcp
.seen
[dir
].flags
|= IP_CT_TCP_FLAG_CLOSE_INIT
;
1055 if (ct
->proto
.tcp
.retrans
>= tn
->tcp_max_retrans
&&
1056 timeouts
[new_state
] > timeouts
[TCP_CONNTRACK_RETRANS
])
1057 timeout
= timeouts
[TCP_CONNTRACK_RETRANS
];
1058 else if ((ct
->proto
.tcp
.seen
[0].flags
| ct
->proto
.tcp
.seen
[1].flags
) &
1059 IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED
&&
1060 timeouts
[new_state
] > timeouts
[TCP_CONNTRACK_UNACK
])
1061 timeout
= timeouts
[TCP_CONNTRACK_UNACK
];
1063 timeout
= timeouts
[new_state
];
1064 spin_unlock_bh(&ct
->lock
);
1066 if (new_state
!= old_state
)
1067 nf_conntrack_event_cache(IPCT_PROTOINFO
, ct
);
1069 if (!test_bit(IPS_SEEN_REPLY_BIT
, &ct
->status
)) {
1070 /* If only reply is a RST, we can consider ourselves not to
1071 have an established connection: this is a fairly common
1072 problem case, so we can delete the conntrack
1073 immediately. --RR */
1075 nf_ct_kill_acct(ct
, ctinfo
, skb
);
1078 /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
1079 * pickup with loose=1. Avoid large ESTABLISHED timeout.
1081 if (new_state
== TCP_CONNTRACK_ESTABLISHED
&&
1082 timeout
> timeouts
[TCP_CONNTRACK_UNACK
])
1083 timeout
= timeouts
[TCP_CONNTRACK_UNACK
];
1084 } else if (!test_bit(IPS_ASSURED_BIT
, &ct
->status
)
1085 && (old_state
== TCP_CONNTRACK_SYN_RECV
1086 || old_state
== TCP_CONNTRACK_ESTABLISHED
)
1087 && new_state
== TCP_CONNTRACK_ESTABLISHED
) {
1088 /* Set ASSURED if we see see valid ack in ESTABLISHED
1089 after SYN_RECV or a valid answer for a picked up
1091 set_bit(IPS_ASSURED_BIT
, &ct
->status
);
1092 nf_conntrack_event_cache(IPCT_ASSURED
, ct
);
1094 nf_ct_refresh_acct(ct
, ctinfo
, skb
, timeout
);
1099 /* Called when a new connection for this protocol found. */
1100 static bool tcp_new(struct nf_conn
*ct
, const struct sk_buff
*skb
,
1101 unsigned int dataoff
, unsigned int *timeouts
)
1103 enum tcp_conntrack new_state
;
1104 const struct tcphdr
*th
;
1105 struct tcphdr _tcph
;
1106 struct net
*net
= nf_ct_net(ct
);
1107 struct nf_tcp_net
*tn
= tcp_pernet(net
);
1108 const struct ip_ct_tcp_state
*sender
= &ct
->proto
.tcp
.seen
[0];
1109 const struct ip_ct_tcp_state
*receiver
= &ct
->proto
.tcp
.seen
[1];
1111 th
= skb_header_pointer(skb
, dataoff
, sizeof(_tcph
), &_tcph
);
1114 /* Don't need lock here: this conntrack not in circulation yet */
1115 new_state
= tcp_conntracks
[0][get_conntrack_index(th
)][TCP_CONNTRACK_NONE
];
1117 /* Invalid: delete conntrack */
1118 if (new_state
>= TCP_CONNTRACK_MAX
) {
1119 pr_debug("nf_ct_tcp: invalid new deleting.\n");
1123 if (new_state
== TCP_CONNTRACK_SYN_SENT
) {
1124 memset(&ct
->proto
.tcp
, 0, sizeof(ct
->proto
.tcp
));
1126 ct
->proto
.tcp
.seen
[0].td_end
=
1127 segment_seq_plus_len(ntohl(th
->seq
), skb
->len
,
1129 ct
->proto
.tcp
.seen
[0].td_maxwin
= ntohs(th
->window
);
1130 if (ct
->proto
.tcp
.seen
[0].td_maxwin
== 0)
1131 ct
->proto
.tcp
.seen
[0].td_maxwin
= 1;
1132 ct
->proto
.tcp
.seen
[0].td_maxend
=
1133 ct
->proto
.tcp
.seen
[0].td_end
;
1135 tcp_options(skb
, dataoff
, th
, &ct
->proto
.tcp
.seen
[0]);
1136 } else if (tn
->tcp_loose
== 0) {
1137 /* Don't try to pick up connections. */
1140 memset(&ct
->proto
.tcp
, 0, sizeof(ct
->proto
.tcp
));
1142 * We are in the middle of a connection,
1143 * its history is lost for us.
1144 * Let's try to use the data from the packet.
1146 ct
->proto
.tcp
.seen
[0].td_end
=
1147 segment_seq_plus_len(ntohl(th
->seq
), skb
->len
,
1149 ct
->proto
.tcp
.seen
[0].td_maxwin
= ntohs(th
->window
);
1150 if (ct
->proto
.tcp
.seen
[0].td_maxwin
== 0)
1151 ct
->proto
.tcp
.seen
[0].td_maxwin
= 1;
1152 ct
->proto
.tcp
.seen
[0].td_maxend
=
1153 ct
->proto
.tcp
.seen
[0].td_end
+
1154 ct
->proto
.tcp
.seen
[0].td_maxwin
;
1156 /* We assume SACK and liberal window checking to handle
1158 ct
->proto
.tcp
.seen
[0].flags
=
1159 ct
->proto
.tcp
.seen
[1].flags
= IP_CT_TCP_FLAG_SACK_PERM
|
1160 IP_CT_TCP_FLAG_BE_LIBERAL
;
1163 /* tcp_packet will set them */
1164 ct
->proto
.tcp
.last_index
= TCP_NONE_SET
;
1166 pr_debug("tcp_new: sender end=%u maxend=%u maxwin=%u scale=%i "
1167 "receiver end=%u maxend=%u maxwin=%u scale=%i\n",
1168 sender
->td_end
, sender
->td_maxend
, sender
->td_maxwin
,
1170 receiver
->td_end
, receiver
->td_maxend
, receiver
->td_maxwin
,
1171 receiver
->td_scale
);
1175 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1177 #include <linux/netfilter/nfnetlink.h>
1178 #include <linux/netfilter/nfnetlink_conntrack.h>
1180 static int tcp_to_nlattr(struct sk_buff
*skb
, struct nlattr
*nla
,
1183 struct nlattr
*nest_parms
;
1184 struct nf_ct_tcp_flags tmp
= {};
1186 spin_lock_bh(&ct
->lock
);
1187 nest_parms
= nla_nest_start(skb
, CTA_PROTOINFO_TCP
| NLA_F_NESTED
);
1189 goto nla_put_failure
;
1191 if (nla_put_u8(skb
, CTA_PROTOINFO_TCP_STATE
, ct
->proto
.tcp
.state
) ||
1192 nla_put_u8(skb
, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL
,
1193 ct
->proto
.tcp
.seen
[0].td_scale
) ||
1194 nla_put_u8(skb
, CTA_PROTOINFO_TCP_WSCALE_REPLY
,
1195 ct
->proto
.tcp
.seen
[1].td_scale
))
1196 goto nla_put_failure
;
1198 tmp
.flags
= ct
->proto
.tcp
.seen
[0].flags
;
1199 if (nla_put(skb
, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL
,
1200 sizeof(struct nf_ct_tcp_flags
), &tmp
))
1201 goto nla_put_failure
;
1203 tmp
.flags
= ct
->proto
.tcp
.seen
[1].flags
;
1204 if (nla_put(skb
, CTA_PROTOINFO_TCP_FLAGS_REPLY
,
1205 sizeof(struct nf_ct_tcp_flags
), &tmp
))
1206 goto nla_put_failure
;
1207 spin_unlock_bh(&ct
->lock
);
1209 nla_nest_end(skb
, nest_parms
);
1214 spin_unlock_bh(&ct
->lock
);
1218 static const struct nla_policy tcp_nla_policy
[CTA_PROTOINFO_TCP_MAX
+1] = {
1219 [CTA_PROTOINFO_TCP_STATE
] = { .type
= NLA_U8
},
1220 [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL
] = { .type
= NLA_U8
},
1221 [CTA_PROTOINFO_TCP_WSCALE_REPLY
] = { .type
= NLA_U8
},
1222 [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL
] = { .len
= sizeof(struct nf_ct_tcp_flags
) },
1223 [CTA_PROTOINFO_TCP_FLAGS_REPLY
] = { .len
= sizeof(struct nf_ct_tcp_flags
) },
1226 static int nlattr_to_tcp(struct nlattr
*cda
[], struct nf_conn
*ct
)
1228 struct nlattr
*pattr
= cda
[CTA_PROTOINFO_TCP
];
1229 struct nlattr
*tb
[CTA_PROTOINFO_TCP_MAX
+1];
1232 /* updates could not contain anything about the private
1233 * protocol info, in that case skip the parsing */
1237 err
= nla_parse_nested(tb
, CTA_PROTOINFO_TCP_MAX
, pattr
, tcp_nla_policy
);
1241 if (tb
[CTA_PROTOINFO_TCP_STATE
] &&
1242 nla_get_u8(tb
[CTA_PROTOINFO_TCP_STATE
]) >= TCP_CONNTRACK_MAX
)
1245 spin_lock_bh(&ct
->lock
);
1246 if (tb
[CTA_PROTOINFO_TCP_STATE
])
1247 ct
->proto
.tcp
.state
= nla_get_u8(tb
[CTA_PROTOINFO_TCP_STATE
]);
1249 if (tb
[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL
]) {
1250 struct nf_ct_tcp_flags
*attr
=
1251 nla_data(tb
[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL
]);
1252 ct
->proto
.tcp
.seen
[0].flags
&= ~attr
->mask
;
1253 ct
->proto
.tcp
.seen
[0].flags
|= attr
->flags
& attr
->mask
;
1256 if (tb
[CTA_PROTOINFO_TCP_FLAGS_REPLY
]) {
1257 struct nf_ct_tcp_flags
*attr
=
1258 nla_data(tb
[CTA_PROTOINFO_TCP_FLAGS_REPLY
]);
1259 ct
->proto
.tcp
.seen
[1].flags
&= ~attr
->mask
;
1260 ct
->proto
.tcp
.seen
[1].flags
|= attr
->flags
& attr
->mask
;
1263 if (tb
[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL
] &&
1264 tb
[CTA_PROTOINFO_TCP_WSCALE_REPLY
] &&
1265 ct
->proto
.tcp
.seen
[0].flags
& IP_CT_TCP_FLAG_WINDOW_SCALE
&&
1266 ct
->proto
.tcp
.seen
[1].flags
& IP_CT_TCP_FLAG_WINDOW_SCALE
) {
1267 ct
->proto
.tcp
.seen
[0].td_scale
=
1268 nla_get_u8(tb
[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL
]);
1269 ct
->proto
.tcp
.seen
[1].td_scale
=
1270 nla_get_u8(tb
[CTA_PROTOINFO_TCP_WSCALE_REPLY
]);
1272 spin_unlock_bh(&ct
->lock
);
1277 static int tcp_nlattr_size(void)
1279 return nla_total_size(0) /* CTA_PROTOINFO_TCP */
1280 + nla_policy_len(tcp_nla_policy
, CTA_PROTOINFO_TCP_MAX
+ 1);
1283 static int tcp_nlattr_tuple_size(void)
1285 return nla_policy_len(nf_ct_port_nla_policy
, CTA_PROTO_MAX
+ 1);
1289 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1291 #include <linux/netfilter/nfnetlink.h>
1292 #include <linux/netfilter/nfnetlink_cttimeout.h>
1294 static int tcp_timeout_nlattr_to_obj(struct nlattr
*tb
[],
1295 struct net
*net
, void *data
)
1297 unsigned int *timeouts
= data
;
1298 struct nf_tcp_net
*tn
= tcp_pernet(net
);
1301 /* set default TCP timeouts. */
1302 for (i
=0; i
<TCP_CONNTRACK_TIMEOUT_MAX
; i
++)
1303 timeouts
[i
] = tn
->timeouts
[i
];
1305 if (tb
[CTA_TIMEOUT_TCP_SYN_SENT
]) {
1306 timeouts
[TCP_CONNTRACK_SYN_SENT
] =
1307 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_SYN_SENT
]))*HZ
;
1309 if (tb
[CTA_TIMEOUT_TCP_SYN_RECV
]) {
1310 timeouts
[TCP_CONNTRACK_SYN_RECV
] =
1311 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_SYN_RECV
]))*HZ
;
1313 if (tb
[CTA_TIMEOUT_TCP_ESTABLISHED
]) {
1314 timeouts
[TCP_CONNTRACK_ESTABLISHED
] =
1315 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_ESTABLISHED
]))*HZ
;
1317 if (tb
[CTA_TIMEOUT_TCP_FIN_WAIT
]) {
1318 timeouts
[TCP_CONNTRACK_FIN_WAIT
] =
1319 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_FIN_WAIT
]))*HZ
;
1321 if (tb
[CTA_TIMEOUT_TCP_CLOSE_WAIT
]) {
1322 timeouts
[TCP_CONNTRACK_CLOSE_WAIT
] =
1323 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_CLOSE_WAIT
]))*HZ
;
1325 if (tb
[CTA_TIMEOUT_TCP_LAST_ACK
]) {
1326 timeouts
[TCP_CONNTRACK_LAST_ACK
] =
1327 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_LAST_ACK
]))*HZ
;
1329 if (tb
[CTA_TIMEOUT_TCP_TIME_WAIT
]) {
1330 timeouts
[TCP_CONNTRACK_TIME_WAIT
] =
1331 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_TIME_WAIT
]))*HZ
;
1333 if (tb
[CTA_TIMEOUT_TCP_CLOSE
]) {
1334 timeouts
[TCP_CONNTRACK_CLOSE
] =
1335 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_CLOSE
]))*HZ
;
1337 if (tb
[CTA_TIMEOUT_TCP_SYN_SENT2
]) {
1338 timeouts
[TCP_CONNTRACK_SYN_SENT2
] =
1339 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_SYN_SENT2
]))*HZ
;
1341 if (tb
[CTA_TIMEOUT_TCP_RETRANS
]) {
1342 timeouts
[TCP_CONNTRACK_RETRANS
] =
1343 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_RETRANS
]))*HZ
;
1345 if (tb
[CTA_TIMEOUT_TCP_UNACK
]) {
1346 timeouts
[TCP_CONNTRACK_UNACK
] =
1347 ntohl(nla_get_be32(tb
[CTA_TIMEOUT_TCP_UNACK
]))*HZ
;
1353 tcp_timeout_obj_to_nlattr(struct sk_buff
*skb
, const void *data
)
1355 const unsigned int *timeouts
= data
;
1357 if (nla_put_be32(skb
, CTA_TIMEOUT_TCP_SYN_SENT
,
1358 htonl(timeouts
[TCP_CONNTRACK_SYN_SENT
] / HZ
)) ||
1359 nla_put_be32(skb
, CTA_TIMEOUT_TCP_SYN_RECV
,
1360 htonl(timeouts
[TCP_CONNTRACK_SYN_RECV
] / HZ
)) ||
1361 nla_put_be32(skb
, CTA_TIMEOUT_TCP_ESTABLISHED
,
1362 htonl(timeouts
[TCP_CONNTRACK_ESTABLISHED
] / HZ
)) ||
1363 nla_put_be32(skb
, CTA_TIMEOUT_TCP_FIN_WAIT
,
1364 htonl(timeouts
[TCP_CONNTRACK_FIN_WAIT
] / HZ
)) ||
1365 nla_put_be32(skb
, CTA_TIMEOUT_TCP_CLOSE_WAIT
,
1366 htonl(timeouts
[TCP_CONNTRACK_CLOSE_WAIT
] / HZ
)) ||
1367 nla_put_be32(skb
, CTA_TIMEOUT_TCP_LAST_ACK
,
1368 htonl(timeouts
[TCP_CONNTRACK_LAST_ACK
] / HZ
)) ||
1369 nla_put_be32(skb
, CTA_TIMEOUT_TCP_TIME_WAIT
,
1370 htonl(timeouts
[TCP_CONNTRACK_TIME_WAIT
] / HZ
)) ||
1371 nla_put_be32(skb
, CTA_TIMEOUT_TCP_CLOSE
,
1372 htonl(timeouts
[TCP_CONNTRACK_CLOSE
] / HZ
)) ||
1373 nla_put_be32(skb
, CTA_TIMEOUT_TCP_SYN_SENT2
,
1374 htonl(timeouts
[TCP_CONNTRACK_SYN_SENT2
] / HZ
)) ||
1375 nla_put_be32(skb
, CTA_TIMEOUT_TCP_RETRANS
,
1376 htonl(timeouts
[TCP_CONNTRACK_RETRANS
] / HZ
)) ||
1377 nla_put_be32(skb
, CTA_TIMEOUT_TCP_UNACK
,
1378 htonl(timeouts
[TCP_CONNTRACK_UNACK
] / HZ
)))
1379 goto nla_put_failure
;
1386 static const struct nla_policy tcp_timeout_nla_policy
[CTA_TIMEOUT_TCP_MAX
+1] = {
1387 [CTA_TIMEOUT_TCP_SYN_SENT
] = { .type
= NLA_U32
},
1388 [CTA_TIMEOUT_TCP_SYN_RECV
] = { .type
= NLA_U32
},
1389 [CTA_TIMEOUT_TCP_ESTABLISHED
] = { .type
= NLA_U32
},
1390 [CTA_TIMEOUT_TCP_FIN_WAIT
] = { .type
= NLA_U32
},
1391 [CTA_TIMEOUT_TCP_CLOSE_WAIT
] = { .type
= NLA_U32
},
1392 [CTA_TIMEOUT_TCP_LAST_ACK
] = { .type
= NLA_U32
},
1393 [CTA_TIMEOUT_TCP_TIME_WAIT
] = { .type
= NLA_U32
},
1394 [CTA_TIMEOUT_TCP_CLOSE
] = { .type
= NLA_U32
},
1395 [CTA_TIMEOUT_TCP_SYN_SENT2
] = { .type
= NLA_U32
},
1396 [CTA_TIMEOUT_TCP_RETRANS
] = { .type
= NLA_U32
},
1397 [CTA_TIMEOUT_TCP_UNACK
] = { .type
= NLA_U32
},
1399 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1401 #ifdef CONFIG_SYSCTL
1402 static struct ctl_table tcp_sysctl_table
[] = {
1404 .procname
= "nf_conntrack_tcp_timeout_syn_sent",
1405 .maxlen
= sizeof(unsigned int),
1407 .proc_handler
= proc_dointvec_jiffies
,
1410 .procname
= "nf_conntrack_tcp_timeout_syn_recv",
1411 .maxlen
= sizeof(unsigned int),
1413 .proc_handler
= proc_dointvec_jiffies
,
1416 .procname
= "nf_conntrack_tcp_timeout_established",
1417 .maxlen
= sizeof(unsigned int),
1419 .proc_handler
= proc_dointvec_jiffies
,
1422 .procname
= "nf_conntrack_tcp_timeout_fin_wait",
1423 .maxlen
= sizeof(unsigned int),
1425 .proc_handler
= proc_dointvec_jiffies
,
1428 .procname
= "nf_conntrack_tcp_timeout_close_wait",
1429 .maxlen
= sizeof(unsigned int),
1431 .proc_handler
= proc_dointvec_jiffies
,
1434 .procname
= "nf_conntrack_tcp_timeout_last_ack",
1435 .maxlen
= sizeof(unsigned int),
1437 .proc_handler
= proc_dointvec_jiffies
,
1440 .procname
= "nf_conntrack_tcp_timeout_time_wait",
1441 .maxlen
= sizeof(unsigned int),
1443 .proc_handler
= proc_dointvec_jiffies
,
1446 .procname
= "nf_conntrack_tcp_timeout_close",
1447 .maxlen
= sizeof(unsigned int),
1449 .proc_handler
= proc_dointvec_jiffies
,
1452 .procname
= "nf_conntrack_tcp_timeout_max_retrans",
1453 .maxlen
= sizeof(unsigned int),
1455 .proc_handler
= proc_dointvec_jiffies
,
1458 .procname
= "nf_conntrack_tcp_timeout_unacknowledged",
1459 .maxlen
= sizeof(unsigned int),
1461 .proc_handler
= proc_dointvec_jiffies
,
1464 .procname
= "nf_conntrack_tcp_loose",
1465 .maxlen
= sizeof(unsigned int),
1467 .proc_handler
= proc_dointvec
,
1470 .procname
= "nf_conntrack_tcp_be_liberal",
1471 .maxlen
= sizeof(unsigned int),
1473 .proc_handler
= proc_dointvec
,
1476 .procname
= "nf_conntrack_tcp_max_retrans",
1477 .maxlen
= sizeof(unsigned int),
1479 .proc_handler
= proc_dointvec
,
1483 #endif /* CONFIG_SYSCTL */
1485 static int tcp_kmemdup_sysctl_table(struct nf_proto_net
*pn
,
1486 struct nf_tcp_net
*tn
)
1488 #ifdef CONFIG_SYSCTL
1492 pn
->ctl_table
= kmemdup(tcp_sysctl_table
,
1493 sizeof(tcp_sysctl_table
),
1498 pn
->ctl_table
[0].data
= &tn
->timeouts
[TCP_CONNTRACK_SYN_SENT
];
1499 pn
->ctl_table
[1].data
= &tn
->timeouts
[TCP_CONNTRACK_SYN_RECV
];
1500 pn
->ctl_table
[2].data
= &tn
->timeouts
[TCP_CONNTRACK_ESTABLISHED
];
1501 pn
->ctl_table
[3].data
= &tn
->timeouts
[TCP_CONNTRACK_FIN_WAIT
];
1502 pn
->ctl_table
[4].data
= &tn
->timeouts
[TCP_CONNTRACK_CLOSE_WAIT
];
1503 pn
->ctl_table
[5].data
= &tn
->timeouts
[TCP_CONNTRACK_LAST_ACK
];
1504 pn
->ctl_table
[6].data
= &tn
->timeouts
[TCP_CONNTRACK_TIME_WAIT
];
1505 pn
->ctl_table
[7].data
= &tn
->timeouts
[TCP_CONNTRACK_CLOSE
];
1506 pn
->ctl_table
[8].data
= &tn
->timeouts
[TCP_CONNTRACK_RETRANS
];
1507 pn
->ctl_table
[9].data
= &tn
->timeouts
[TCP_CONNTRACK_UNACK
];
1508 pn
->ctl_table
[10].data
= &tn
->tcp_loose
;
1509 pn
->ctl_table
[11].data
= &tn
->tcp_be_liberal
;
1510 pn
->ctl_table
[12].data
= &tn
->tcp_max_retrans
;
1515 static int tcp_init_net(struct net
*net
, u_int16_t proto
)
1517 struct nf_tcp_net
*tn
= tcp_pernet(net
);
1518 struct nf_proto_net
*pn
= &tn
->pn
;
1523 for (i
= 0; i
< TCP_CONNTRACK_TIMEOUT_MAX
; i
++)
1524 tn
->timeouts
[i
] = tcp_timeouts
[i
];
1526 tn
->tcp_loose
= nf_ct_tcp_loose
;
1527 tn
->tcp_be_liberal
= nf_ct_tcp_be_liberal
;
1528 tn
->tcp_max_retrans
= nf_ct_tcp_max_retrans
;
1531 return tcp_kmemdup_sysctl_table(pn
, tn
);
1534 static struct nf_proto_net
*tcp_get_net_proto(struct net
*net
)
1536 return &net
->ct
.nf_ct_proto
.tcp
.pn
;
1539 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly
=
1542 .l4proto
= IPPROTO_TCP
,
1544 .pkt_to_tuple
= tcp_pkt_to_tuple
,
1545 .invert_tuple
= tcp_invert_tuple
,
1546 .print_tuple
= tcp_print_tuple
,
1547 .print_conntrack
= tcp_print_conntrack
,
1548 .packet
= tcp_packet
,
1549 .get_timeouts
= tcp_get_timeouts
,
1552 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1553 .to_nlattr
= tcp_to_nlattr
,
1554 .nlattr_size
= tcp_nlattr_size
,
1555 .from_nlattr
= nlattr_to_tcp
,
1556 .tuple_to_nlattr
= nf_ct_port_tuple_to_nlattr
,
1557 .nlattr_to_tuple
= nf_ct_port_nlattr_to_tuple
,
1558 .nlattr_tuple_size
= tcp_nlattr_tuple_size
,
1559 .nla_policy
= nf_ct_port_nla_policy
,
1561 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1563 .nlattr_to_obj
= tcp_timeout_nlattr_to_obj
,
1564 .obj_to_nlattr
= tcp_timeout_obj_to_nlattr
,
1565 .nlattr_max
= CTA_TIMEOUT_TCP_MAX
,
1566 .obj_size
= sizeof(unsigned int) *
1567 TCP_CONNTRACK_TIMEOUT_MAX
,
1568 .nla_policy
= tcp_timeout_nla_policy
,
1570 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1571 .init_net
= tcp_init_net
,
1572 .get_net_proto
= tcp_get_net_proto
,
1574 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4
);
1576 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6 __read_mostly
=
1578 .l3proto
= PF_INET6
,
1579 .l4proto
= IPPROTO_TCP
,
1581 .pkt_to_tuple
= tcp_pkt_to_tuple
,
1582 .invert_tuple
= tcp_invert_tuple
,
1583 .print_tuple
= tcp_print_tuple
,
1584 .print_conntrack
= tcp_print_conntrack
,
1585 .packet
= tcp_packet
,
1586 .get_timeouts
= tcp_get_timeouts
,
1589 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1590 .to_nlattr
= tcp_to_nlattr
,
1591 .nlattr_size
= tcp_nlattr_size
,
1592 .from_nlattr
= nlattr_to_tcp
,
1593 .tuple_to_nlattr
= nf_ct_port_tuple_to_nlattr
,
1594 .nlattr_to_tuple
= nf_ct_port_nlattr_to_tuple
,
1595 .nlattr_tuple_size
= tcp_nlattr_tuple_size
,
1596 .nla_policy
= nf_ct_port_nla_policy
,
1598 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
1600 .nlattr_to_obj
= tcp_timeout_nlattr_to_obj
,
1601 .obj_to_nlattr
= tcp_timeout_obj_to_nlattr
,
1602 .nlattr_max
= CTA_TIMEOUT_TCP_MAX
,
1603 .obj_size
= sizeof(unsigned int) *
1604 TCP_CONNTRACK_TIMEOUT_MAX
,
1605 .nla_policy
= tcp_timeout_nla_policy
,
1607 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
1608 .init_net
= tcp_init_net
,
1609 .get_net_proto
= tcp_get_net_proto
,
1611 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6
);