Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9fb9cbb1 YK |
2 | /* (C) 1999-2001 Paul `Rusty' Russell |
3 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
fe03d474 | 4 | * (C) 2002-2013 Jozsef Kadlecsik <kadlec@netfilter.org> |
f229f6ce | 5 | * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
9fb9cbb1 YK |
6 | */ |
7 | ||
9fb9cbb1 | 8 | #include <linux/types.h> |
9fb9cbb1 | 9 | #include <linux/timer.h> |
9fb9cbb1 YK |
10 | #include <linux/module.h> |
11 | #include <linux/in.h> | |
12 | #include <linux/tcp.h> | |
13 | #include <linux/spinlock.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/ipv6.h> | |
16 | #include <net/ip6_checksum.h> | |
534f81a5 | 17 | #include <asm/unaligned.h> |
9fb9cbb1 YK |
18 | |
19 | #include <net/tcp.h> | |
20 | ||
21 | #include <linux/netfilter.h> | |
22 | #include <linux/netfilter_ipv4.h> | |
23 | #include <linux/netfilter_ipv6.h> | |
24 | #include <net/netfilter/nf_conntrack.h> | |
605dcad6 | 25 | #include <net/netfilter/nf_conntrack_l4proto.h> |
f6180121 | 26 | #include <net/netfilter/nf_conntrack_ecache.h> |
41d73ec0 | 27 | #include <net/netfilter/nf_conntrack_seqadj.h> |
48b1de4c | 28 | #include <net/netfilter/nf_conntrack_synproxy.h> |
c779e849 | 29 | #include <net/netfilter/nf_conntrack_timeout.h> |
f01ffbd6 | 30 | #include <net/netfilter/nf_log.h> |
9d2493f8 CP |
31 | #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> |
32 | #include <net/netfilter/ipv6/nf_conntrack_ipv6.h> | |
9fb9cbb1 | 33 | |
601e68e1 YH |
34 | /* "Be conservative in what you do, |
35 | be liberal in what you accept from others." | |
9fb9cbb1 | 36 | If it's non-zero, we mark only out of window RST segments as INVALID. */ |
3aef0fd9 | 37 | static int nf_ct_tcp_be_liberal __read_mostly = 0; |
9fb9cbb1 | 38 | |
a09113c2 | 39 | /* If it is set to zero, we disable picking up already established |
9fb9cbb1 | 40 | connections. */ |
3aef0fd9 | 41 | static int nf_ct_tcp_loose __read_mostly = 1; |
9fb9cbb1 | 42 | |
601e68e1 YH |
43 | /* Max number of the retransmitted packets without receiving an (acceptable) |
44 | ACK from the destination. If this number is reached, a shorter timer | |
9fb9cbb1 | 45 | will be started. */ |
3aef0fd9 | 46 | static int nf_ct_tcp_max_retrans __read_mostly = 3; |
9fb9cbb1 YK |
47 | |
48 | /* FIXME: Examine ipfilter's timeouts and conntrack transitions more | |
49 | closely. They're more complex. --RR */ | |
50 | ||
82f568fc | 51 | static const char *const tcp_conntrack_names[] = { |
9fb9cbb1 YK |
52 | "NONE", |
53 | "SYN_SENT", | |
54 | "SYN_RECV", | |
55 | "ESTABLISHED", | |
56 | "FIN_WAIT", | |
57 | "CLOSE_WAIT", | |
58 | "LAST_ACK", | |
59 | "TIME_WAIT", | |
60 | "CLOSE", | |
874ab923 | 61 | "SYN_SENT2", |
9fb9cbb1 | 62 | }; |
601e68e1 | 63 | |
9fb9cbb1 YK |
64 | #define SECS * HZ |
65 | #define MINS * 60 SECS | |
66 | #define HOURS * 60 MINS | |
67 | #define DAYS * 24 HOURS | |
68 | ||
2c9e8637 | 69 | static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = { |
2d646286 PM |
70 | [TCP_CONNTRACK_SYN_SENT] = 2 MINS, |
71 | [TCP_CONNTRACK_SYN_RECV] = 60 SECS, | |
72 | [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS, | |
73 | [TCP_CONNTRACK_FIN_WAIT] = 2 MINS, | |
74 | [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS, | |
75 | [TCP_CONNTRACK_LAST_ACK] = 30 SECS, | |
76 | [TCP_CONNTRACK_TIME_WAIT] = 2 MINS, | |
77 | [TCP_CONNTRACK_CLOSE] = 10 SECS, | |
874ab923 | 78 | [TCP_CONNTRACK_SYN_SENT2] = 2 MINS, |
33ee4464 PNA |
79 | /* RFC1122 says the R2 limit should be at least 100 seconds. |
80 | Linux uses 15 packets as limit, which corresponds | |
81 | to ~13-30min depending on RTO. */ | |
82 | [TCP_CONNTRACK_RETRANS] = 5 MINS, | |
83 | [TCP_CONNTRACK_UNACK] = 5 MINS, | |
2d646286 | 84 | }; |
601e68e1 | 85 | |
9fb9cbb1 YK |
86 | #define sNO TCP_CONNTRACK_NONE |
87 | #define sSS TCP_CONNTRACK_SYN_SENT | |
88 | #define sSR TCP_CONNTRACK_SYN_RECV | |
89 | #define sES TCP_CONNTRACK_ESTABLISHED | |
90 | #define sFW TCP_CONNTRACK_FIN_WAIT | |
91 | #define sCW TCP_CONNTRACK_CLOSE_WAIT | |
92 | #define sLA TCP_CONNTRACK_LAST_ACK | |
93 | #define sTW TCP_CONNTRACK_TIME_WAIT | |
94 | #define sCL TCP_CONNTRACK_CLOSE | |
874ab923 | 95 | #define sS2 TCP_CONNTRACK_SYN_SENT2 |
9fb9cbb1 YK |
96 | #define sIV TCP_CONNTRACK_MAX |
97 | #define sIG TCP_CONNTRACK_IGNORE | |
98 | ||
99 | /* What TCP flags are set from RST/SYN/FIN/ACK. */ | |
100 | enum tcp_bit_set { | |
101 | TCP_SYN_SET, | |
102 | TCP_SYNACK_SET, | |
103 | TCP_FIN_SET, | |
104 | TCP_ACK_SET, | |
105 | TCP_RST_SET, | |
106 | TCP_NONE_SET, | |
107 | }; | |
601e68e1 | 108 | |
9fb9cbb1 YK |
109 | /* |
110 | * The TCP state transition table needs a few words... | |
111 | * | |
112 | * We are the man in the middle. All the packets go through us | |
113 | * but might get lost in transit to the destination. | |
601e68e1 | 114 | * It is assumed that the destinations can't receive segments |
9fb9cbb1 YK |
115 | * we haven't seen. |
116 | * | |
117 | * The checked segment is in window, but our windows are *not* | |
118 | * equivalent with the ones of the sender/receiver. We always | |
119 | * try to guess the state of the current sender. | |
120 | * | |
121 | * The meaning of the states are: | |
122 | * | |
123 | * NONE: initial state | |
601e68e1 | 124 | * SYN_SENT: SYN-only packet seen |
874ab923 | 125 | * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open |
9fb9cbb1 YK |
126 | * SYN_RECV: SYN-ACK packet seen |
127 | * ESTABLISHED: ACK packet seen | |
128 | * FIN_WAIT: FIN packet seen | |
601e68e1 | 129 | * CLOSE_WAIT: ACK seen (after FIN) |
9fb9cbb1 YK |
130 | * LAST_ACK: FIN seen (after FIN) |
131 | * TIME_WAIT: last ACK seen | |
b2155e7f | 132 | * CLOSE: closed connection (RST) |
9fb9cbb1 | 133 | * |
9fb9cbb1 | 134 | * Packets marked as IGNORED (sIG): |
601e68e1 YH |
135 | * if they may be either invalid or valid |
136 | * and the receiver may send back a connection | |
9fb9cbb1 YK |
137 | * closing RST or a SYN/ACK. |
138 | * | |
139 | * Packets marked as INVALID (sIV): | |
874ab923 | 140 | * if we regard them as truly invalid packets |
9fb9cbb1 | 141 | */ |
a5e73c29 | 142 | static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { |
9fb9cbb1 YK |
143 | { |
144 | /* ORIGINAL */ | |
874ab923 JK |
145 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
146 | /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 }, | |
9fb9cbb1 YK |
147 | /* |
148 | * sNO -> sSS Initialize a new connection | |
149 | * sSS -> sSS Retransmitted SYN | |
874ab923 JK |
150 | * sS2 -> sS2 Late retransmitted SYN |
151 | * sSR -> sIG | |
9fb9cbb1 | 152 | * sES -> sIG Error: SYNs in window outside the SYN_SENT state |
601e68e1 | 153 | * are errors. Receiver will reply with RST |
9fb9cbb1 YK |
154 | * and close the connection. |
155 | * Or we are not in sync and hold a dead connection. | |
156 | * sFW -> sIG | |
157 | * sCW -> sIG | |
158 | * sLA -> sIG | |
159 | * sTW -> sSS Reopened connection (RFC 1122). | |
160 | * sCL -> sSS | |
161 | */ | |
874ab923 | 162 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
64f509ce | 163 | /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR }, |
9fb9cbb1 | 164 | /* |
874ab923 JK |
165 | * sNO -> sIV Too late and no reason to do anything |
166 | * sSS -> sIV Client can't send SYN and then SYN/ACK | |
167 | * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open | |
64f509ce JK |
168 | * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open |
169 | * sES -> sIV Invalid SYN/ACK packets sent by the client | |
170 | * sFW -> sIV | |
171 | * sCW -> sIV | |
172 | * sLA -> sIV | |
173 | * sTW -> sIV | |
174 | * sCL -> sIV | |
9fb9cbb1 | 175 | */ |
874ab923 | 176 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
177 | /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
178 | /* | |
179 | * sNO -> sIV Too late and no reason to do anything... | |
180 | * sSS -> sIV Client migth not send FIN in this state: | |
181 | * we enforce waiting for a SYN/ACK reply first. | |
874ab923 | 182 | * sS2 -> sIV |
9fb9cbb1 YK |
183 | * sSR -> sFW Close started. |
184 | * sES -> sFW | |
185 | * sFW -> sLA FIN seen in both directions, waiting for | |
601e68e1 | 186 | * the last ACK. |
9fb9cbb1 YK |
187 | * Migth be a retransmitted FIN as well... |
188 | * sCW -> sLA | |
189 | * sLA -> sLA Retransmitted FIN. Remain in the same state. | |
190 | * sTW -> sTW | |
191 | * sCL -> sCL | |
192 | */ | |
874ab923 | 193 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
194 | /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV }, |
195 | /* | |
196 | * sNO -> sES Assumed. | |
197 | * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet. | |
874ab923 | 198 | * sS2 -> sIV |
9fb9cbb1 YK |
199 | * sSR -> sES Established state is reached. |
200 | * sES -> sES :-) | |
201 | * sFW -> sCW Normal close request answered by ACK. | |
202 | * sCW -> sCW | |
b3cad287 | 203 | * sLA -> sTW Last ACK detected (RFC5961 challenged) |
9fb9cbb1 YK |
204 | * sTW -> sTW Retransmitted last ACK. Remain in the same state. |
205 | * sCL -> sCL | |
206 | */ | |
874ab923 JK |
207 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
208 | /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, | |
9fb9cbb1 YK |
209 | /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
210 | }, | |
211 | { | |
212 | /* REPLY */ | |
874ab923 | 213 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
e37ad9fd | 214 | /*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 }, |
9fb9cbb1 YK |
215 | /* |
216 | * sNO -> sIV Never reached. | |
874ab923 JK |
217 | * sSS -> sS2 Simultaneous open |
218 | * sS2 -> sS2 Retransmitted simultaneous SYN | |
219 | * sSR -> sIV Invalid SYN packets sent by the server | |
220 | * sES -> sIV | |
9fb9cbb1 YK |
221 | * sFW -> sIV |
222 | * sCW -> sIV | |
223 | * sLA -> sIV | |
e37ad9fd | 224 | * sTW -> sSS Reopened connection, but server may have switched role |
9fb9cbb1 YK |
225 | * sCL -> sIV |
226 | */ | |
874ab923 | 227 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
8a80c79a | 228 | /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, |
9fb9cbb1 YK |
229 | /* |
230 | * sSS -> sSR Standard open. | |
874ab923 | 231 | * sS2 -> sSR Simultaneous open |
8a80c79a | 232 | * sSR -> sIG Retransmitted SYN/ACK, ignore it. |
9fb9cbb1 YK |
233 | * sES -> sIG Late retransmitted SYN/ACK? |
234 | * sFW -> sIG Might be SYN/ACK answering ignored SYN | |
235 | * sCW -> sIG | |
236 | * sLA -> sIG | |
237 | * sTW -> sIG | |
238 | * sCL -> sIG | |
239 | */ | |
874ab923 | 240 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
241 | /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
242 | /* | |
243 | * sSS -> sIV Server might not send FIN in this state. | |
874ab923 | 244 | * sS2 -> sIV |
9fb9cbb1 YK |
245 | * sSR -> sFW Close started. |
246 | * sES -> sFW | |
247 | * sFW -> sLA FIN seen in both directions. | |
248 | * sCW -> sLA | |
249 | * sLA -> sLA Retransmitted FIN. | |
250 | * sTW -> sTW | |
251 | * sCL -> sCL | |
252 | */ | |
874ab923 JK |
253 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
254 | /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG }, | |
9fb9cbb1 | 255 | /* |
73f30602 | 256 | * sSS -> sIG Might be a half-open connection. |
874ab923 | 257 | * sS2 -> sIG |
9fb9cbb1 YK |
258 | * sSR -> sSR Might answer late resent SYN. |
259 | * sES -> sES :-) | |
260 | * sFW -> sCW Normal close request answered by ACK. | |
261 | * sCW -> sCW | |
b3cad287 | 262 | * sLA -> sTW Last ACK detected (RFC5961 challenged) |
9fb9cbb1 YK |
263 | * sTW -> sTW Retransmitted last ACK. |
264 | * sCL -> sCL | |
265 | */ | |
874ab923 JK |
266 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
267 | /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, | |
9fb9cbb1 | 268 | /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
601e68e1 | 269 | } |
9fb9cbb1 YK |
270 | }; |
271 | ||
ea48cc83 | 272 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
9fb9cbb1 | 273 | /* Print out the private part of the conntrack. */ |
37246a58 | 274 | static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
9fb9cbb1 | 275 | { |
90964016 PNA |
276 | if (test_bit(IPS_OFFLOAD_BIT, &ct->status)) |
277 | return; | |
278 | ||
a163f2cb | 279 | seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]); |
9fb9cbb1 | 280 | } |
ea48cc83 | 281 | #endif |
9fb9cbb1 YK |
282 | |
283 | static unsigned int get_conntrack_index(const struct tcphdr *tcph) | |
284 | { | |
285 | if (tcph->rst) return TCP_RST_SET; | |
286 | else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET); | |
287 | else if (tcph->fin) return TCP_FIN_SET; | |
288 | else if (tcph->ack) return TCP_ACK_SET; | |
289 | else return TCP_NONE_SET; | |
290 | } | |
291 | ||
292 | /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering | |
293 | in IP Filter' by Guido van Rooij. | |
601e68e1 | 294 | |
631dd1a8 JM |
295 | http://www.sane.nl/events/sane2000/papers.html |
296 | http://www.darkart.com/mirrors/www.obfuscation.org/ipf/ | |
601e68e1 | 297 | |
9fb9cbb1 YK |
298 | The boundaries and the conditions are changed according to RFC793: |
299 | the packet must intersect the window (i.e. segments may be | |
300 | after the right or before the left edge) and thus receivers may ACK | |
301 | segments after the right edge of the window. | |
302 | ||
601e68e1 | 303 | td_maxend = max(sack + max(win,1)) seen in reply packets |
9fb9cbb1 YK |
304 | td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets |
305 | td_maxwin += seq + len - sender.td_maxend | |
306 | if seq + len > sender.td_maxend | |
307 | td_end = max(seq + len) seen in sent packets | |
601e68e1 | 308 | |
9fb9cbb1 YK |
309 | I. Upper bound for valid data: seq <= sender.td_maxend |
310 | II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin | |
84ebe1cd JK |
311 | III. Upper bound for valid (s)ack: sack <= receiver.td_end |
312 | IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW | |
9fb9cbb1 | 313 | |
84ebe1cd JK |
314 | where sack is the highest right edge of sack block found in the packet |
315 | or ack in the case of packet without SACK option. | |
9fb9cbb1 | 316 | |
84ebe1cd | 317 | The upper bound limit for a valid (s)ack is not ignored - |
601e68e1 | 318 | we doesn't have to deal with fragments. |
9fb9cbb1 YK |
319 | */ |
320 | ||
321 | static inline __u32 segment_seq_plus_len(__u32 seq, | |
322 | size_t len, | |
323 | unsigned int dataoff, | |
82f568fc | 324 | const struct tcphdr *tcph) |
9fb9cbb1 YK |
325 | { |
326 | /* XXX Should I use payload length field in IP/IPv6 header ? | |
327 | * - YK */ | |
328 | return (seq + len - dataoff - tcph->doff*4 | |
329 | + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0)); | |
330 | } | |
601e68e1 | 331 | |
9fb9cbb1 YK |
332 | /* Fixme: what about big packets? */ |
333 | #define MAXACKWINCONST 66000 | |
334 | #define MAXACKWINDOW(sender) \ | |
335 | ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \ | |
336 | : MAXACKWINCONST) | |
601e68e1 | 337 | |
9fb9cbb1 YK |
338 | /* |
339 | * Simplified tcp_parse_options routine from tcp_input.c | |
340 | */ | |
341 | static void tcp_options(const struct sk_buff *skb, | |
342 | unsigned int dataoff, | |
82f568fc | 343 | const struct tcphdr *tcph, |
9fb9cbb1 YK |
344 | struct ip_ct_tcp_state *state) |
345 | { | |
346 | unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; | |
82f568fc | 347 | const unsigned char *ptr; |
9fb9cbb1 YK |
348 | int length = (tcph->doff*4) - sizeof(struct tcphdr); |
349 | ||
350 | if (!length) | |
351 | return; | |
352 | ||
353 | ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), | |
354 | length, buff); | |
355 | BUG_ON(ptr == NULL); | |
356 | ||
601e68e1 | 357 | state->td_scale = |
9fb9cbb1 YK |
358 | state->flags = 0; |
359 | ||
360 | while (length > 0) { | |
361 | int opcode=*ptr++; | |
362 | int opsize; | |
363 | ||
364 | switch (opcode) { | |
365 | case TCPOPT_EOL: | |
366 | return; | |
367 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
368 | length--; | |
369 | continue; | |
370 | default: | |
644c7e48 JK |
371 | if (length < 2) |
372 | return; | |
9fb9cbb1 YK |
373 | opsize=*ptr++; |
374 | if (opsize < 2) /* "silly options" */ | |
375 | return; | |
376 | if (opsize > length) | |
4a5cc84a | 377 | return; /* don't parse partial options */ |
9fb9cbb1 | 378 | |
601e68e1 | 379 | if (opcode == TCPOPT_SACK_PERM |
9fb9cbb1 YK |
380 | && opsize == TCPOLEN_SACK_PERM) |
381 | state->flags |= IP_CT_TCP_FLAG_SACK_PERM; | |
382 | else if (opcode == TCPOPT_WINDOW | |
383 | && opsize == TCPOLEN_WINDOW) { | |
384 | state->td_scale = *(u_int8_t *)ptr; | |
385 | ||
122868b3 GF |
386 | if (state->td_scale > TCP_MAX_WSCALE) |
387 | state->td_scale = TCP_MAX_WSCALE; | |
388 | ||
9fb9cbb1 YK |
389 | state->flags |= |
390 | IP_CT_TCP_FLAG_WINDOW_SCALE; | |
391 | } | |
392 | ptr += opsize - 2; | |
393 | length -= opsize; | |
394 | } | |
395 | } | |
396 | } | |
397 | ||
398 | static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff, | |
82f568fc | 399 | const struct tcphdr *tcph, __u32 *sack) |
9fb9cbb1 | 400 | { |
601e68e1 | 401 | unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; |
82f568fc | 402 | const unsigned char *ptr; |
9fb9cbb1 YK |
403 | int length = (tcph->doff*4) - sizeof(struct tcphdr); |
404 | __u32 tmp; | |
405 | ||
406 | if (!length) | |
407 | return; | |
408 | ||
409 | ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), | |
410 | length, buff); | |
411 | BUG_ON(ptr == NULL); | |
412 | ||
413 | /* Fast path for timestamp-only option */ | |
bb9fc373 | 414 | if (length == TCPOLEN_TSTAMP_ALIGNED |
8f05ce91 YH |
415 | && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24) |
416 | | (TCPOPT_NOP << 16) | |
417 | | (TCPOPT_TIMESTAMP << 8) | |
418 | | TCPOLEN_TIMESTAMP)) | |
9fb9cbb1 YK |
419 | return; |
420 | ||
421 | while (length > 0) { | |
422 | int opcode = *ptr++; | |
423 | int opsize, i; | |
424 | ||
425 | switch (opcode) { | |
426 | case TCPOPT_EOL: | |
427 | return; | |
428 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
429 | length--; | |
430 | continue; | |
431 | default: | |
644c7e48 JK |
432 | if (length < 2) |
433 | return; | |
9fb9cbb1 YK |
434 | opsize = *ptr++; |
435 | if (opsize < 2) /* "silly options" */ | |
436 | return; | |
437 | if (opsize > length) | |
4a5cc84a | 438 | return; /* don't parse partial options */ |
9fb9cbb1 | 439 | |
601e68e1 YH |
440 | if (opcode == TCPOPT_SACK |
441 | && opsize >= (TCPOLEN_SACK_BASE | |
442 | + TCPOLEN_SACK_PERBLOCK) | |
443 | && !((opsize - TCPOLEN_SACK_BASE) | |
444 | % TCPOLEN_SACK_PERBLOCK)) { | |
445 | for (i = 0; | |
446 | i < (opsize - TCPOLEN_SACK_BASE); | |
447 | i += TCPOLEN_SACK_PERBLOCK) { | |
534f81a5 | 448 | tmp = get_unaligned_be32((__be32 *)(ptr+i)+1); |
9fb9cbb1 YK |
449 | |
450 | if (after(tmp, *sack)) | |
451 | *sack = tmp; | |
452 | } | |
453 | return; | |
454 | } | |
455 | ptr += opsize - 2; | |
456 | length -= opsize; | |
457 | } | |
458 | } | |
459 | } | |
460 | ||
09f263cd JE |
461 | static bool tcp_in_window(const struct nf_conn *ct, |
462 | struct ip_ct_tcp *state, | |
463 | enum ip_conntrack_dir dir, | |
464 | unsigned int index, | |
465 | const struct sk_buff *skb, | |
466 | unsigned int dataoff, | |
eb6fad5a | 467 | const struct tcphdr *tcph) |
9fb9cbb1 | 468 | { |
c2a2c7e0 | 469 | struct net *net = nf_ct_net(ct); |
a95a7774 | 470 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
9fb9cbb1 YK |
471 | struct ip_ct_tcp_state *sender = &state->seen[dir]; |
472 | struct ip_ct_tcp_state *receiver = &state->seen[!dir]; | |
82f568fc | 473 | const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple; |
9fb9cbb1 | 474 | __u32 seq, ack, sack, end, win, swin; |
959b69ef | 475 | u16 win_raw; |
2d89c68a | 476 | s32 receiver_offset; |
356d7d88 | 477 | bool res, in_recv_win; |
9fb9cbb1 YK |
478 | |
479 | /* | |
480 | * Get the required data from the packet. | |
481 | */ | |
482 | seq = ntohl(tcph->seq); | |
483 | ack = sack = ntohl(tcph->ack_seq); | |
959b69ef FW |
484 | win_raw = ntohs(tcph->window); |
485 | win = win_raw; | |
9fb9cbb1 YK |
486 | end = segment_seq_plus_len(seq, skb->len, dataoff, tcph); |
487 | ||
488 | if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM) | |
489 | tcp_sack(skb, dataoff, tcph, &sack); | |
490 | ||
f9dd09c7 | 491 | /* Take into account NAT sequence number mangling */ |
41d73ec0 | 492 | receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1); |
f9dd09c7 JK |
493 | ack -= receiver_offset; |
494 | sack -= receiver_offset; | |
495 | ||
0d53778e PM |
496 | pr_debug("tcp_in_window: START\n"); |
497 | pr_debug("tcp_in_window: "); | |
3c9fba65 | 498 | nf_ct_dump_tuple(tuple); |
f9dd09c7 JK |
499 | pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
500 | seq, ack, receiver_offset, sack, receiver_offset, win, end); | |
0d53778e PM |
501 | pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
502 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
503 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
504 | sender->td_scale, | |
505 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
506 | receiver->td_scale); | |
9fb9cbb1 | 507 | |
874ab923 | 508 | if (sender->td_maxwin == 0) { |
9fb9cbb1 YK |
509 | /* |
510 | * Initialize sender data. | |
511 | */ | |
874ab923 | 512 | if (tcph->syn) { |
9fb9cbb1 | 513 | /* |
874ab923 JK |
514 | * SYN-ACK in reply to a SYN |
515 | * or SYN from reply direction in simultaneous open. | |
9fb9cbb1 | 516 | */ |
601e68e1 | 517 | sender->td_end = |
9fb9cbb1 YK |
518 | sender->td_maxend = end; |
519 | sender->td_maxwin = (win == 0 ? 1 : win); | |
520 | ||
521 | tcp_options(skb, dataoff, tcph, sender); | |
601e68e1 | 522 | /* |
9fb9cbb1 YK |
523 | * RFC 1323: |
524 | * Both sides must send the Window Scale option | |
525 | * to enable window scaling in either direction. | |
526 | */ | |
527 | if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE | |
528 | && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) | |
601e68e1 | 529 | sender->td_scale = |
9fb9cbb1 | 530 | receiver->td_scale = 0; |
874ab923 JK |
531 | if (!tcph->ack) |
532 | /* Simultaneous open */ | |
533 | return true; | |
9fb9cbb1 YK |
534 | } else { |
535 | /* | |
536 | * We are in the middle of a connection, | |
537 | * its history is lost for us. | |
538 | * Let's try to use the data from the packet. | |
601e68e1 | 539 | */ |
9fb9cbb1 | 540 | sender->td_end = end; |
6ee0b693 CG |
541 | swin = win << sender->td_scale; |
542 | sender->td_maxwin = (swin == 0 ? 1 : swin); | |
9fb9cbb1 | 543 | sender->td_maxend = end + sender->td_maxwin; |
fac42a9a PNA |
544 | /* |
545 | * We haven't seen traffic in the other direction yet | |
546 | * but we have to tweak window tracking to pass III | |
547 | * and IV until that happens. | |
548 | */ | |
549 | if (receiver->td_maxwin == 0) | |
550 | receiver->td_end = receiver->td_maxend = sack; | |
9fb9cbb1 YK |
551 | } |
552 | } else if (((state->state == TCP_CONNTRACK_SYN_SENT | |
553 | && dir == IP_CT_DIR_ORIGINAL) | |
554 | || (state->state == TCP_CONNTRACK_SYN_RECV | |
555 | && dir == IP_CT_DIR_REPLY)) | |
556 | && after(end, sender->td_end)) { | |
557 | /* | |
558 | * RFC 793: "if a TCP is reinitialized ... then it need | |
601e68e1 | 559 | * not wait at all; it must only be sure to use sequence |
9fb9cbb1 YK |
560 | * numbers larger than those recently used." |
561 | */ | |
562 | sender->td_end = | |
563 | sender->td_maxend = end; | |
564 | sender->td_maxwin = (win == 0 ? 1 : win); | |
565 | ||
566 | tcp_options(skb, dataoff, tcph, sender); | |
567 | } | |
568 | ||
569 | if (!(tcph->ack)) { | |
570 | /* | |
571 | * If there is no ACK, just pretend it was set and OK. | |
572 | */ | |
573 | ack = sack = receiver->td_end; | |
601e68e1 YH |
574 | } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) == |
575 | (TCP_FLAG_ACK|TCP_FLAG_RST)) | |
9fb9cbb1 YK |
576 | && (ack == 0)) { |
577 | /* | |
578 | * Broken TCP stacks, that set ACK in RST packets as well | |
579 | * with zero ack value. | |
580 | */ | |
581 | ack = sack = receiver->td_end; | |
582 | } | |
583 | ||
4a70bbfa | 584 | if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT) |
9fb9cbb1 | 585 | /* |
4a70bbfa | 586 | * RST sent answering SYN. |
9fb9cbb1 YK |
587 | */ |
588 | seq = end = sender->td_end; | |
589 | ||
0d53778e | 590 | pr_debug("tcp_in_window: "); |
3c9fba65 | 591 | nf_ct_dump_tuple(tuple); |
f9dd09c7 JK |
592 | pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
593 | seq, ack, receiver_offset, sack, receiver_offset, win, end); | |
0d53778e PM |
594 | pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
595 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
596 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
597 | sender->td_scale, | |
598 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
599 | receiver->td_scale); | |
600 | ||
356d7d88 YC |
601 | /* Is the ending sequence in the receive window (if available)? */ |
602 | in_recv_win = !receiver->td_maxwin || | |
603 | after(end, sender->td_end - receiver->td_maxwin - 1); | |
604 | ||
0d53778e PM |
605 | pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n", |
606 | before(seq, sender->td_maxend + 1), | |
356d7d88 | 607 | (in_recv_win ? 1 : 0), |
0d53778e | 608 | before(sack, receiver->td_end + 1), |
84ebe1cd | 609 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)); |
9fb9cbb1 | 610 | |
a09113c2 | 611 | if (before(seq, sender->td_maxend + 1) && |
356d7d88 | 612 | in_recv_win && |
a09113c2 | 613 | before(sack, receiver->td_end + 1) && |
84ebe1cd | 614 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) { |
601e68e1 | 615 | /* |
9fb9cbb1 YK |
616 | * Take into account window scaling (RFC 1323). |
617 | */ | |
618 | if (!tcph->syn) | |
619 | win <<= sender->td_scale; | |
620 | ||
621 | /* | |
622 | * Update sender data. | |
623 | */ | |
624 | swin = win + (sack - ack); | |
625 | if (sender->td_maxwin < swin) | |
626 | sender->td_maxwin = swin; | |
ae375044 | 627 | if (after(end, sender->td_end)) { |
9fb9cbb1 | 628 | sender->td_end = end; |
ae375044 PM |
629 | sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; |
630 | } | |
bfcaa502 JK |
631 | if (tcph->ack) { |
632 | if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) { | |
633 | sender->td_maxack = ack; | |
634 | sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET; | |
635 | } else if (after(ack, sender->td_maxack)) | |
636 | sender->td_maxack = ack; | |
637 | } | |
638 | ||
9fb9cbb1 YK |
639 | /* |
640 | * Update receiver data. | |
641 | */ | |
fac42a9a | 642 | if (receiver->td_maxwin != 0 && after(end, sender->td_maxend)) |
9fb9cbb1 YK |
643 | receiver->td_maxwin += end - sender->td_maxend; |
644 | if (after(sack + win, receiver->td_maxend - 1)) { | |
645 | receiver->td_maxend = sack + win; | |
646 | if (win == 0) | |
647 | receiver->td_maxend++; | |
648 | } | |
ae375044 PM |
649 | if (ack == receiver->td_end) |
650 | receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; | |
9fb9cbb1 | 651 | |
601e68e1 | 652 | /* |
9fb9cbb1 YK |
653 | * Check retransmissions. |
654 | */ | |
655 | if (index == TCP_ACK_SET) { | |
656 | if (state->last_dir == dir | |
657 | && state->last_seq == seq | |
658 | && state->last_ack == ack | |
c1fe3ca5 | 659 | && state->last_end == end |
959b69ef | 660 | && state->last_win == win_raw) |
9fb9cbb1 YK |
661 | state->retrans++; |
662 | else { | |
663 | state->last_dir = dir; | |
664 | state->last_seq = seq; | |
665 | state->last_ack = ack; | |
666 | state->last_end = end; | |
959b69ef | 667 | state->last_win = win_raw; |
9fb9cbb1 YK |
668 | state->retrans = 0; |
669 | } | |
670 | } | |
09f263cd | 671 | res = true; |
9fb9cbb1 | 672 | } else { |
09f263cd | 673 | res = false; |
a09113c2 | 674 | if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL || |
d2ba1fde | 675 | tn->tcp_be_liberal) |
09f263cd | 676 | res = true; |
3d0b527b FW |
677 | if (!res) { |
678 | nf_ct_l4proto_log_invalid(skb, ct, | |
679 | "%s", | |
9fb9cbb1 | 680 | before(seq, sender->td_maxend + 1) ? |
356d7d88 | 681 | in_recv_win ? |
9fb9cbb1 | 682 | before(sack, receiver->td_end + 1) ? |
f9dd09c7 | 683 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG" |
9fb9cbb1 YK |
684 | : "ACK is under the lower bound (possible overly delayed ACK)" |
685 | : "ACK is over the upper bound (ACKed data not seen yet)" | |
686 | : "SEQ is under the lower bound (already ACKed data retransmitted)" | |
687 | : "SEQ is over the upper bound (over the window of the receiver)"); | |
3d0b527b | 688 | } |
601e68e1 YH |
689 | } |
690 | ||
09f263cd | 691 | pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u " |
0d53778e PM |
692 | "receiver end=%u maxend=%u maxwin=%u\n", |
693 | res, sender->td_end, sender->td_maxend, sender->td_maxwin, | |
694 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin); | |
9fb9cbb1 YK |
695 | |
696 | return res; | |
697 | } | |
698 | ||
5c8ce7c9 | 699 | /* table of valid flag combinations - PUSH, ECE and CWR are always valid */ |
a3433f35 CG |
700 | static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK| |
701 | TCPHDR_URG) + 1] = | |
9fb9cbb1 | 702 | { |
a3433f35 CG |
703 | [TCPHDR_SYN] = 1, |
704 | [TCPHDR_SYN|TCPHDR_URG] = 1, | |
705 | [TCPHDR_SYN|TCPHDR_ACK] = 1, | |
706 | [TCPHDR_RST] = 1, | |
707 | [TCPHDR_RST|TCPHDR_ACK] = 1, | |
708 | [TCPHDR_FIN|TCPHDR_ACK] = 1, | |
709 | [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1, | |
710 | [TCPHDR_ACK] = 1, | |
711 | [TCPHDR_ACK|TCPHDR_URG] = 1, | |
9fb9cbb1 YK |
712 | }; |
713 | ||
93e66024 FW |
714 | static void tcp_error_log(const struct sk_buff *skb, |
715 | const struct nf_hook_state *state, | |
716 | const char *msg) | |
c4f3db15 | 717 | { |
93e66024 | 718 | nf_l4proto_log_invalid(skb, state->net, state->pf, IPPROTO_TCP, "%s", msg); |
c4f3db15 FW |
719 | } |
720 | ||
9fb9cbb1 | 721 | /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */ |
0150ffba FW |
722 | static bool tcp_error(const struct tcphdr *th, |
723 | struct sk_buff *skb, | |
724 | unsigned int dataoff, | |
725 | const struct nf_hook_state *state) | |
9fb9cbb1 | 726 | { |
9fb9cbb1 | 727 | unsigned int tcplen = skb->len - dataoff; |
0150ffba | 728 | u8 tcpflags; |
601e68e1 | 729 | |
9fb9cbb1 YK |
730 | /* Not whole TCP header or malformed packet */ |
731 | if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) { | |
93e66024 | 732 | tcp_error_log(skb, state, "truncated packet"); |
0150ffba | 733 | return true; |
9fb9cbb1 | 734 | } |
601e68e1 | 735 | |
9fb9cbb1 YK |
736 | /* Checksum invalid? Ignore. |
737 | * We skip checking packets on the outgoing path | |
84fa7933 | 738 | * because the checksum is assumed to be correct. |
9fb9cbb1 YK |
739 | */ |
740 | /* FIXME: Source route IP option packets --RR */ | |
93e66024 FW |
741 | if (state->net->ct.sysctl_checksum && |
742 | state->hook == NF_INET_PRE_ROUTING && | |
743 | nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) { | |
744 | tcp_error_log(skb, state, "bad checksum"); | |
0150ffba | 745 | return true; |
9fb9cbb1 YK |
746 | } |
747 | ||
748 | /* Check TCP flags. */ | |
a3433f35 | 749 | tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH)); |
9fb9cbb1 | 750 | if (!tcp_valid_flags[tcpflags]) { |
93e66024 | 751 | tcp_error_log(skb, state, "invalid tcp flag combination"); |
0150ffba | 752 | return true; |
9fb9cbb1 YK |
753 | } |
754 | ||
0150ffba | 755 | return false; |
9fb9cbb1 YK |
756 | } |
757 | ||
9976fc6e FW |
758 | static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, |
759 | unsigned int dataoff, | |
760 | const struct tcphdr *th) | |
761 | { | |
762 | enum tcp_conntrack new_state; | |
763 | struct net *net = nf_ct_net(ct); | |
a95a7774 | 764 | const struct nf_tcp_net *tn = nf_tcp_pernet(net); |
9976fc6e FW |
765 | const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0]; |
766 | const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1]; | |
767 | ||
768 | /* Don't need lock here: this conntrack not in circulation yet */ | |
769 | new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE]; | |
770 | ||
771 | /* Invalid: delete conntrack */ | |
772 | if (new_state >= TCP_CONNTRACK_MAX) { | |
773 | pr_debug("nf_ct_tcp: invalid new deleting.\n"); | |
774 | return false; | |
775 | } | |
776 | ||
777 | if (new_state == TCP_CONNTRACK_SYN_SENT) { | |
778 | memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); | |
779 | /* SYN packet */ | |
780 | ct->proto.tcp.seen[0].td_end = | |
781 | segment_seq_plus_len(ntohl(th->seq), skb->len, | |
782 | dataoff, th); | |
783 | ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); | |
784 | if (ct->proto.tcp.seen[0].td_maxwin == 0) | |
785 | ct->proto.tcp.seen[0].td_maxwin = 1; | |
786 | ct->proto.tcp.seen[0].td_maxend = | |
787 | ct->proto.tcp.seen[0].td_end; | |
788 | ||
789 | tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]); | |
790 | } else if (tn->tcp_loose == 0) { | |
791 | /* Don't try to pick up connections. */ | |
792 | return false; | |
793 | } else { | |
794 | memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); | |
795 | /* | |
796 | * We are in the middle of a connection, | |
797 | * its history is lost for us. | |
798 | * Let's try to use the data from the packet. | |
799 | */ | |
800 | ct->proto.tcp.seen[0].td_end = | |
801 | segment_seq_plus_len(ntohl(th->seq), skb->len, | |
802 | dataoff, th); | |
803 | ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); | |
804 | if (ct->proto.tcp.seen[0].td_maxwin == 0) | |
805 | ct->proto.tcp.seen[0].td_maxwin = 1; | |
806 | ct->proto.tcp.seen[0].td_maxend = | |
807 | ct->proto.tcp.seen[0].td_end + | |
808 | ct->proto.tcp.seen[0].td_maxwin; | |
809 | ||
810 | /* We assume SACK and liberal window checking to handle | |
811 | * window scaling */ | |
812 | ct->proto.tcp.seen[0].flags = | |
813 | ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM | | |
814 | IP_CT_TCP_FLAG_BE_LIBERAL; | |
815 | } | |
816 | ||
817 | /* tcp_packet will set them */ | |
818 | ct->proto.tcp.last_index = TCP_NONE_SET; | |
819 | ||
820 | pr_debug("%s: sender end=%u maxend=%u maxwin=%u scale=%i " | |
821 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
822 | __func__, | |
823 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
824 | sender->td_scale, | |
825 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
826 | receiver->td_scale); | |
827 | return true; | |
9fb9cbb1 YK |
828 | } |
829 | ||
be0502a3 FW |
830 | static bool nf_conntrack_tcp_established(const struct nf_conn *ct) |
831 | { | |
832 | return ct->proto.tcp.state == TCP_CONNTRACK_ESTABLISHED && | |
833 | test_bit(IPS_ASSURED_BIT, &ct->status); | |
834 | } | |
835 | ||
9fb9cbb1 | 836 | /* Returns verdict for packet, or -1 for invalid. */ |
a47c5404 FW |
837 | int nf_conntrack_tcp_packet(struct nf_conn *ct, |
838 | struct sk_buff *skb, | |
839 | unsigned int dataoff, | |
840 | enum ip_conntrack_info ctinfo, | |
841 | const struct nf_hook_state *state) | |
9fb9cbb1 | 842 | { |
c2a2c7e0 | 843 | struct net *net = nf_ct_net(ct); |
a95a7774 | 844 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
0d53778e | 845 | struct nf_conntrack_tuple *tuple; |
9fb9cbb1 | 846 | enum tcp_conntrack new_state, old_state; |
c779e849 | 847 | unsigned int index, *timeouts; |
9fb9cbb1 | 848 | enum ip_conntrack_dir dir; |
82f568fc JE |
849 | const struct tcphdr *th; |
850 | struct tcphdr _tcph; | |
9fb9cbb1 | 851 | unsigned long timeout; |
9fb9cbb1 YK |
852 | |
853 | th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); | |
9976fc6e FW |
854 | if (th == NULL) |
855 | return -NF_ACCEPT; | |
856 | ||
0150ffba FW |
857 | if (tcp_error(th, skb, dataoff, state)) |
858 | return -NF_ACCEPT; | |
859 | ||
9976fc6e FW |
860 | if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th)) |
861 | return -NF_ACCEPT; | |
9fb9cbb1 | 862 | |
440f0d58 | 863 | spin_lock_bh(&ct->lock); |
c88130bc | 864 | old_state = ct->proto.tcp.state; |
9fb9cbb1 YK |
865 | dir = CTINFO2DIR(ctinfo); |
866 | index = get_conntrack_index(th); | |
867 | new_state = tcp_conntracks[dir][index][old_state]; | |
c88130bc | 868 | tuple = &ct->tuplehash[dir].tuple; |
9fb9cbb1 YK |
869 | |
870 | switch (new_state) { | |
17311393 JK |
871 | case TCP_CONNTRACK_SYN_SENT: |
872 | if (old_state < TCP_CONNTRACK_TIME_WAIT) | |
873 | break; | |
b2155e7f JK |
874 | /* RFC 1122: "When a connection is closed actively, |
875 | * it MUST linger in TIME-WAIT state for a time 2xMSL | |
876 | * (Maximum Segment Lifetime). However, it MAY accept | |
877 | * a new SYN from the remote TCP to reopen the connection | |
878 | * directly from TIME-WAIT state, if..." | |
879 | * We ignore the conditions because we are in the | |
880 | * TIME-WAIT state anyway. | |
881 | * | |
882 | * Handle aborted connections: we and the server | |
883 | * think there is an existing connection but the client | |
884 | * aborts it and starts a new one. | |
885 | */ | |
886 | if (((ct->proto.tcp.seen[dir].flags | |
887 | | ct->proto.tcp.seen[!dir].flags) | |
888 | & IP_CT_TCP_FLAG_CLOSE_INIT) | |
c88130bc PM |
889 | || (ct->proto.tcp.last_dir == dir |
890 | && ct->proto.tcp.last_index == TCP_RST_SET)) { | |
bc34b841 JK |
891 | /* Attempt to reopen a closed/aborted connection. |
892 | * Delete this connection and look up again. */ | |
440f0d58 | 893 | spin_unlock_bh(&ct->lock); |
2aec609f | 894 | |
6b69fe0c PM |
895 | /* Only repeat if we can actually remove the timer. |
896 | * Destruction may already be in progress in process | |
897 | * context and we must give it a chance to terminate. | |
898 | */ | |
2aec609f | 899 | if (nf_ct_kill(ct)) |
6b69fe0c | 900 | return -NF_REPEAT; |
ec8d5409 | 901 | return NF_DROP; |
17311393 JK |
902 | } |
903 | /* Fall through */ | |
9fb9cbb1 | 904 | case TCP_CONNTRACK_IGNORE: |
73f30602 | 905 | /* Ignored packets: |
b2155e7f JK |
906 | * |
907 | * Our connection entry may be out of sync, so ignore | |
908 | * packets which may signal the real connection between | |
909 | * the client and the server. | |
73f30602 JK |
910 | * |
911 | * a) SYN in ORIGINAL | |
912 | * b) SYN/ACK in REPLY | |
601e68e1 | 913 | * c) ACK in reply direction after initial SYN in original. |
b2155e7f JK |
914 | * |
915 | * If the ignored packet is invalid, the receiver will send | |
916 | * a RST we'll catch below. | |
73f30602 | 917 | */ |
9fb9cbb1 | 918 | if (index == TCP_SYNACK_SET |
c88130bc PM |
919 | && ct->proto.tcp.last_index == TCP_SYN_SET |
920 | && ct->proto.tcp.last_dir != dir | |
921 | && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { | |
b2155e7f | 922 | /* b) This SYN/ACK acknowledges a SYN that we earlier |
9fb9cbb1 YK |
923 | * ignored as invalid. This means that the client and |
924 | * the server are both in sync, while the firewall is | |
c4832c7b PNA |
925 | * not. We get in sync from the previously annotated |
926 | * values. | |
9fb9cbb1 | 927 | */ |
c4832c7b PNA |
928 | old_state = TCP_CONNTRACK_SYN_SENT; |
929 | new_state = TCP_CONNTRACK_SYN_RECV; | |
930 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end = | |
931 | ct->proto.tcp.last_end; | |
932 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend = | |
933 | ct->proto.tcp.last_end; | |
934 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin = | |
935 | ct->proto.tcp.last_win == 0 ? | |
936 | 1 : ct->proto.tcp.last_win; | |
937 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale = | |
938 | ct->proto.tcp.last_wscale; | |
b3cad287 | 939 | ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; |
c4832c7b PNA |
940 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags = |
941 | ct->proto.tcp.last_flags; | |
942 | memset(&ct->proto.tcp.seen[dir], 0, | |
943 | sizeof(struct ip_ct_tcp_state)); | |
944 | break; | |
9fb9cbb1 | 945 | } |
c88130bc PM |
946 | ct->proto.tcp.last_index = index; |
947 | ct->proto.tcp.last_dir = dir; | |
948 | ct->proto.tcp.last_seq = ntohl(th->seq); | |
949 | ct->proto.tcp.last_end = | |
9fb9cbb1 | 950 | segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th); |
c4832c7b PNA |
951 | ct->proto.tcp.last_win = ntohs(th->window); |
952 | ||
953 | /* a) This is a SYN in ORIGINAL. The client and the server | |
954 | * may be in sync but we are not. In that case, we annotate | |
955 | * the TCP options and let the packet go through. If it is a | |
956 | * valid SYN packet, the server will reply with a SYN/ACK, and | |
b3cad287 JDB |
957 | * then we'll get in sync. Otherwise, the server potentially |
958 | * responds with a challenge ACK if implementing RFC5961. | |
959 | */ | |
c4832c7b PNA |
960 | if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) { |
961 | struct ip_ct_tcp_state seen = {}; | |
962 | ||
963 | ct->proto.tcp.last_flags = | |
964 | ct->proto.tcp.last_wscale = 0; | |
965 | tcp_options(skb, dataoff, th, &seen); | |
966 | if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { | |
967 | ct->proto.tcp.last_flags |= | |
968 | IP_CT_TCP_FLAG_WINDOW_SCALE; | |
969 | ct->proto.tcp.last_wscale = seen.td_scale; | |
970 | } | |
971 | if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) { | |
972 | ct->proto.tcp.last_flags |= | |
973 | IP_CT_TCP_FLAG_SACK_PERM; | |
974 | } | |
b3cad287 JDB |
975 | /* Mark the potential for RFC5961 challenge ACK, |
976 | * this pose a special problem for LAST_ACK state | |
977 | * as ACK is intrepretated as ACKing last FIN. | |
978 | */ | |
979 | if (old_state == TCP_CONNTRACK_LAST_ACK) | |
980 | ct->proto.tcp.last_flags |= | |
981 | IP_CT_EXP_CHALLENGE_ACK; | |
c4832c7b | 982 | } |
440f0d58 | 983 | spin_unlock_bh(&ct->lock); |
3d0b527b FW |
984 | nf_ct_l4proto_log_invalid(skb, ct, "invalid packet ignored in " |
985 | "state %s ", tcp_conntrack_names[old_state]); | |
9fb9cbb1 YK |
986 | return NF_ACCEPT; |
987 | case TCP_CONNTRACK_MAX: | |
48b1de4c PM |
988 | /* Special case for SYN proxy: when the SYN to the server or |
989 | * the SYN/ACK from the server is lost, the client may transmit | |
990 | * a keep-alive packet while in SYN_SENT state. This needs to | |
991 | * be associated with the original conntrack entry in order to | |
992 | * generate a new SYN with the correct sequence number. | |
993 | */ | |
994 | if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT && | |
995 | index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL && | |
996 | ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL && | |
997 | ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) { | |
998 | pr_debug("nf_ct_tcp: SYN proxy client keep alive\n"); | |
999 | spin_unlock_bh(&ct->lock); | |
1000 | return NF_ACCEPT; | |
1001 | } | |
1002 | ||
9fb9cbb1 | 1003 | /* Invalid packet */ |
0d53778e PM |
1004 | pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n", |
1005 | dir, get_conntrack_index(th), old_state); | |
440f0d58 | 1006 | spin_unlock_bh(&ct->lock); |
3d0b527b | 1007 | nf_ct_l4proto_log_invalid(skb, ct, "invalid state"); |
9fb9cbb1 | 1008 | return -NF_ACCEPT; |
b3cad287 JDB |
1009 | case TCP_CONNTRACK_TIME_WAIT: |
1010 | /* RFC5961 compliance cause stack to send "challenge-ACK" | |
1011 | * e.g. in response to spurious SYNs. Conntrack MUST | |
1012 | * not believe this ACK is acking last FIN. | |
1013 | */ | |
1014 | if (old_state == TCP_CONNTRACK_LAST_ACK && | |
1015 | index == TCP_ACK_SET && | |
1016 | ct->proto.tcp.last_dir != dir && | |
1017 | ct->proto.tcp.last_index == TCP_SYN_SET && | |
1018 | (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) { | |
1019 | /* Detected RFC5961 challenge ACK */ | |
1020 | ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; | |
1021 | spin_unlock_bh(&ct->lock); | |
3d0b527b | 1022 | nf_ct_l4proto_log_invalid(skb, ct, "challenge-ack ignored"); |
b3cad287 JDB |
1023 | return NF_ACCEPT; /* Don't change state */ |
1024 | } | |
1025 | break; | |
72d4d3e3 JK |
1026 | case TCP_CONNTRACK_SYN_SENT2: |
1027 | /* tcp_conntracks table is not smart enough to handle | |
1028 | * simultaneous open. | |
1029 | */ | |
1030 | ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN; | |
1031 | break; | |
1032 | case TCP_CONNTRACK_SYN_RECV: | |
1033 | if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET && | |
1034 | ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN) | |
1035 | new_state = TCP_CONNTRACK_ESTABLISHED; | |
1036 | break; | |
9fb9cbb1 | 1037 | case TCP_CONNTRACK_CLOSE: |
be0502a3 FW |
1038 | if (index != TCP_RST_SET) |
1039 | break; | |
1040 | ||
1041 | if (ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) { | |
1042 | u32 seq = ntohl(th->seq); | |
1043 | ||
1044 | if (before(seq, ct->proto.tcp.seen[!dir].td_maxack)) { | |
1045 | /* Invalid RST */ | |
1046 | spin_unlock_bh(&ct->lock); | |
1047 | nf_ct_l4proto_log_invalid(skb, ct, "invalid rst"); | |
1048 | return -NF_ACCEPT; | |
1049 | } | |
1050 | ||
1051 | if (!nf_conntrack_tcp_established(ct) || | |
1052 | seq == ct->proto.tcp.seen[!dir].td_maxack) | |
1053 | break; | |
1054 | ||
1055 | /* Check if rst is part of train, such as | |
1056 | * foo:80 > bar:4379: P, 235946583:235946602(19) ack 42 | |
1057 | * foo:80 > bar:4379: R, 235946602:235946602(0) ack 42 | |
1058 | */ | |
1059 | if (ct->proto.tcp.last_index == TCP_ACK_SET && | |
1060 | ct->proto.tcp.last_dir == dir && | |
1061 | seq == ct->proto.tcp.last_end) | |
1062 | break; | |
1063 | ||
1064 | /* ... RST sequence number doesn't match exactly, keep | |
1065 | * established state to allow a possible challenge ACK. | |
1066 | */ | |
1067 | new_state = old_state; | |
bfcaa502 | 1068 | } |
be0502a3 | 1069 | if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status) |
c88130bc PM |
1070 | && ct->proto.tcp.last_index == TCP_SYN_SET) |
1071 | || (!test_bit(IPS_ASSURED_BIT, &ct->status) | |
1072 | && ct->proto.tcp.last_index == TCP_ACK_SET)) | |
1073 | && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { | |
93b1fae4 | 1074 | /* RST sent to invalid SYN or ACK we had let through |
73f30602 JK |
1075 | * at a) and c) above: |
1076 | * | |
1077 | * a) SYN was in window then | |
1078 | * c) we hold a half-open connection. | |
1079 | * | |
1080 | * Delete our connection entry. | |
9fb9cbb1 | 1081 | * We skip window checking, because packet might ACK |
73f30602 | 1082 | * segments we ignored. */ |
9fb9cbb1 YK |
1083 | goto in_window; |
1084 | } | |
be0502a3 | 1085 | break; |
9fb9cbb1 YK |
1086 | default: |
1087 | /* Keep compilers happy. */ | |
1088 | break; | |
1089 | } | |
1090 | ||
c88130bc | 1091 | if (!tcp_in_window(ct, &ct->proto.tcp, dir, index, |
eb6fad5a | 1092 | skb, dataoff, th)) { |
440f0d58 | 1093 | spin_unlock_bh(&ct->lock); |
9fb9cbb1 YK |
1094 | return -NF_ACCEPT; |
1095 | } | |
1096 | in_window: | |
1097 | /* From now on we have got in-window packets */ | |
c88130bc PM |
1098 | ct->proto.tcp.last_index = index; |
1099 | ct->proto.tcp.last_dir = dir; | |
9fb9cbb1 | 1100 | |
0d53778e | 1101 | pr_debug("tcp_conntracks: "); |
3c9fba65 | 1102 | nf_ct_dump_tuple(tuple); |
0d53778e PM |
1103 | pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n", |
1104 | (th->syn ? 1 : 0), (th->ack ? 1 : 0), | |
1105 | (th->fin ? 1 : 0), (th->rst ? 1 : 0), | |
1106 | old_state, new_state); | |
9fb9cbb1 | 1107 | |
c88130bc | 1108 | ct->proto.tcp.state = new_state; |
9fb9cbb1 | 1109 | if (old_state != new_state |
d0c1fd7a | 1110 | && new_state == TCP_CONNTRACK_FIN_WAIT) |
c88130bc | 1111 | ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT; |
ae375044 | 1112 | |
c779e849 FW |
1113 | timeouts = nf_ct_timeout_lookup(ct); |
1114 | if (!timeouts) | |
1115 | timeouts = tn->timeouts; | |
1116 | ||
d2ba1fde | 1117 | if (ct->proto.tcp.retrans >= tn->tcp_max_retrans && |
2c8503f5 PNA |
1118 | timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) |
1119 | timeout = timeouts[TCP_CONNTRACK_RETRANS]; | |
be0502a3 FW |
1120 | else if (unlikely(index == TCP_RST_SET)) |
1121 | timeout = timeouts[TCP_CONNTRACK_CLOSE]; | |
ae375044 PM |
1122 | else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) & |
1123 | IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED && | |
2c8503f5 PNA |
1124 | timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK]) |
1125 | timeout = timeouts[TCP_CONNTRACK_UNACK]; | |
fbcd253d FW |
1126 | else if (ct->proto.tcp.last_win == 0 && |
1127 | timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) | |
1128 | timeout = timeouts[TCP_CONNTRACK_RETRANS]; | |
ae375044 | 1129 | else |
2c8503f5 | 1130 | timeout = timeouts[new_state]; |
440f0d58 | 1131 | spin_unlock_bh(&ct->lock); |
9fb9cbb1 | 1132 | |
9fb9cbb1 | 1133 | if (new_state != old_state) |
a71996fc | 1134 | nf_conntrack_event_cache(IPCT_PROTOINFO, ct); |
9fb9cbb1 | 1135 | |
c88130bc | 1136 | if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
9fb9cbb1 YK |
1137 | /* If only reply is a RST, we can consider ourselves not to |
1138 | have an established connection: this is a fairly common | |
1139 | problem case, so we can delete the conntrack | |
1140 | immediately. --RR */ | |
1141 | if (th->rst) { | |
718d4ad9 | 1142 | nf_ct_kill_acct(ct, ctinfo, skb); |
9fb9cbb1 YK |
1143 | return NF_ACCEPT; |
1144 | } | |
6547a221 FW |
1145 | /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection |
1146 | * pickup with loose=1. Avoid large ESTABLISHED timeout. | |
1147 | */ | |
1148 | if (new_state == TCP_CONNTRACK_ESTABLISHED && | |
1149 | timeout > timeouts[TCP_CONNTRACK_UNACK]) | |
1150 | timeout = timeouts[TCP_CONNTRACK_UNACK]; | |
c88130bc | 1151 | } else if (!test_bit(IPS_ASSURED_BIT, &ct->status) |
9fb9cbb1 YK |
1152 | && (old_state == TCP_CONNTRACK_SYN_RECV |
1153 | || old_state == TCP_CONNTRACK_ESTABLISHED) | |
1154 | && new_state == TCP_CONNTRACK_ESTABLISHED) { | |
601e68e1 YH |
1155 | /* Set ASSURED if we see see valid ack in ESTABLISHED |
1156 | after SYN_RECV or a valid answer for a picked up | |
9fb9cbb1 | 1157 | connection. */ |
c88130bc | 1158 | set_bit(IPS_ASSURED_BIT, &ct->status); |
858b3133 | 1159 | nf_conntrack_event_cache(IPCT_ASSURED, ct); |
9fb9cbb1 | 1160 | } |
c88130bc | 1161 | nf_ct_refresh_acct(ct, ctinfo, skb, timeout); |
9fb9cbb1 YK |
1162 | |
1163 | return NF_ACCEPT; | |
1164 | } | |
601e68e1 | 1165 | |
c6dd940b FW |
1166 | static bool tcp_can_early_drop(const struct nf_conn *ct) |
1167 | { | |
1168 | switch (ct->proto.tcp.state) { | |
1169 | case TCP_CONNTRACK_FIN_WAIT: | |
1170 | case TCP_CONNTRACK_LAST_ACK: | |
1171 | case TCP_CONNTRACK_TIME_WAIT: | |
1172 | case TCP_CONNTRACK_CLOSE: | |
1173 | case TCP_CONNTRACK_CLOSE_WAIT: | |
1174 | return true; | |
1175 | default: | |
1176 | break; | |
1177 | } | |
1178 | ||
1179 | return false; | |
1180 | } | |
1181 | ||
c0cd1156 | 1182 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
c1d10adb PNA |
1183 | |
1184 | #include <linux/netfilter/nfnetlink.h> | |
1185 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
1186 | ||
fdf70832 | 1187 | static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
440f0d58 | 1188 | struct nf_conn *ct) |
c1d10adb | 1189 | { |
df6fb868 | 1190 | struct nlattr *nest_parms; |
c8e2078c | 1191 | struct nf_ct_tcp_flags tmp = {}; |
601e68e1 | 1192 | |
440f0d58 | 1193 | spin_lock_bh(&ct->lock); |
ae0be8de | 1194 | nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP); |
df6fb868 PM |
1195 | if (!nest_parms) |
1196 | goto nla_put_failure; | |
1197 | ||
4925a459 DM |
1198 | if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state) || |
1199 | nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, | |
1200 | ct->proto.tcp.seen[0].td_scale) || | |
1201 | nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, | |
1202 | ct->proto.tcp.seen[1].td_scale)) | |
1203 | goto nla_put_failure; | |
c8e2078c PNA |
1204 | |
1205 | tmp.flags = ct->proto.tcp.seen[0].flags; | |
4925a459 DM |
1206 | if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL, |
1207 | sizeof(struct nf_ct_tcp_flags), &tmp)) | |
1208 | goto nla_put_failure; | |
c8e2078c PNA |
1209 | |
1210 | tmp.flags = ct->proto.tcp.seen[1].flags; | |
4925a459 DM |
1211 | if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY, |
1212 | sizeof(struct nf_ct_tcp_flags), &tmp)) | |
1213 | goto nla_put_failure; | |
440f0d58 | 1214 | spin_unlock_bh(&ct->lock); |
c1d10adb | 1215 | |
df6fb868 | 1216 | nla_nest_end(skb, nest_parms); |
c1d10adb PNA |
1217 | |
1218 | return 0; | |
1219 | ||
df6fb868 | 1220 | nla_put_failure: |
440f0d58 | 1221 | spin_unlock_bh(&ct->lock); |
c1d10adb PNA |
1222 | return -1; |
1223 | } | |
1224 | ||
f73e924c PM |
1225 | static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = { |
1226 | [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 }, | |
1227 | [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 }, | |
1228 | [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 }, | |
1229 | [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) }, | |
7e59b3fe | 1230 | [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) }, |
c1d10adb PNA |
1231 | }; |
1232 | ||
39215846 FW |
1233 | #define TCP_NLATTR_SIZE ( \ |
1234 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
1235 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
346fa83d | 1236 | NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \ |
1237 | NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags))) | |
39215846 | 1238 | |
fdf70832 | 1239 | static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct) |
c1d10adb | 1240 | { |
2f0d2f10 | 1241 | struct nlattr *pattr = cda[CTA_PROTOINFO_TCP]; |
df6fb868 | 1242 | struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1]; |
f73e924c | 1243 | int err; |
c1d10adb PNA |
1244 | |
1245 | /* updates could not contain anything about the private | |
1246 | * protocol info, in that case skip the parsing */ | |
2f0d2f10 | 1247 | if (!pattr) |
c1d10adb PNA |
1248 | return 0; |
1249 | ||
8cb08174 JB |
1250 | err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, pattr, |
1251 | tcp_nla_policy, NULL); | |
f73e924c PM |
1252 | if (err < 0) |
1253 | return err; | |
c1d10adb | 1254 | |
5f7da4d2 PM |
1255 | if (tb[CTA_PROTOINFO_TCP_STATE] && |
1256 | nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX) | |
c1d10adb PNA |
1257 | return -EINVAL; |
1258 | ||
440f0d58 | 1259 | spin_lock_bh(&ct->lock); |
5f7da4d2 PM |
1260 | if (tb[CTA_PROTOINFO_TCP_STATE]) |
1261 | ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]); | |
c8e2078c | 1262 | |
df6fb868 | 1263 | if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) { |
c8e2078c | 1264 | struct nf_ct_tcp_flags *attr = |
df6fb868 | 1265 | nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]); |
c8e2078c PNA |
1266 | ct->proto.tcp.seen[0].flags &= ~attr->mask; |
1267 | ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask; | |
1268 | } | |
1269 | ||
df6fb868 | 1270 | if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) { |
c8e2078c | 1271 | struct nf_ct_tcp_flags *attr = |
df6fb868 | 1272 | nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]); |
c8e2078c PNA |
1273 | ct->proto.tcp.seen[1].flags &= ~attr->mask; |
1274 | ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask; | |
1275 | } | |
1276 | ||
df6fb868 PM |
1277 | if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] && |
1278 | tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] && | |
c8e2078c PNA |
1279 | ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE && |
1280 | ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { | |
77236b6e PM |
1281 | ct->proto.tcp.seen[0].td_scale = |
1282 | nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]); | |
1283 | ct->proto.tcp.seen[1].td_scale = | |
1284 | nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]); | |
c8e2078c | 1285 | } |
440f0d58 | 1286 | spin_unlock_bh(&ct->lock); |
c1d10adb PNA |
1287 | |
1288 | return 0; | |
1289 | } | |
a400c30e | 1290 | |
5caaed15 | 1291 | static unsigned int tcp_nlattr_tuple_size(void) |
a400c30e | 1292 | { |
5caaed15 FW |
1293 | static unsigned int size __read_mostly; |
1294 | ||
1295 | if (!size) | |
1296 | size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); | |
1297 | ||
1298 | return size; | |
a400c30e | 1299 | } |
c1d10adb | 1300 | #endif |
933a41e7 | 1301 | |
a874752a | 1302 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
1303 | |
1304 | #include <linux/netfilter/nfnetlink.h> | |
1305 | #include <linux/netfilter/nfnetlink_cttimeout.h> | |
1306 | ||
8264deb8 G |
1307 | static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[], |
1308 | struct net *net, void *data) | |
50978462 | 1309 | { |
a95a7774 | 1310 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
c779e849 | 1311 | unsigned int *timeouts = data; |
50978462 PNA |
1312 | int i; |
1313 | ||
c779e849 FW |
1314 | if (!timeouts) |
1315 | timeouts = tn->timeouts; | |
50978462 PNA |
1316 | /* set default TCP timeouts. */ |
1317 | for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++) | |
8264deb8 | 1318 | timeouts[i] = tn->timeouts[i]; |
50978462 PNA |
1319 | |
1320 | if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) { | |
1321 | timeouts[TCP_CONNTRACK_SYN_SENT] = | |
1322 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ; | |
1323 | } | |
ef39078d | 1324 | |
50978462 PNA |
1325 | if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) { |
1326 | timeouts[TCP_CONNTRACK_SYN_RECV] = | |
1327 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ; | |
1328 | } | |
1329 | if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) { | |
1330 | timeouts[TCP_CONNTRACK_ESTABLISHED] = | |
1331 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ; | |
1332 | } | |
1333 | if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) { | |
1334 | timeouts[TCP_CONNTRACK_FIN_WAIT] = | |
1335 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ; | |
1336 | } | |
1337 | if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) { | |
1338 | timeouts[TCP_CONNTRACK_CLOSE_WAIT] = | |
1339 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ; | |
1340 | } | |
1341 | if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) { | |
1342 | timeouts[TCP_CONNTRACK_LAST_ACK] = | |
1343 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ; | |
1344 | } | |
1345 | if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) { | |
1346 | timeouts[TCP_CONNTRACK_TIME_WAIT] = | |
1347 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ; | |
1348 | } | |
1349 | if (tb[CTA_TIMEOUT_TCP_CLOSE]) { | |
1350 | timeouts[TCP_CONNTRACK_CLOSE] = | |
1351 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ; | |
1352 | } | |
1353 | if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) { | |
1354 | timeouts[TCP_CONNTRACK_SYN_SENT2] = | |
1355 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ; | |
1356 | } | |
1357 | if (tb[CTA_TIMEOUT_TCP_RETRANS]) { | |
1358 | timeouts[TCP_CONNTRACK_RETRANS] = | |
1359 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ; | |
1360 | } | |
1361 | if (tb[CTA_TIMEOUT_TCP_UNACK]) { | |
1362 | timeouts[TCP_CONNTRACK_UNACK] = | |
1363 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ; | |
1364 | } | |
ef39078d FW |
1365 | |
1366 | timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT]; | |
50978462 PNA |
1367 | return 0; |
1368 | } | |
1369 | ||
1370 | static int | |
1371 | tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) | |
1372 | { | |
1373 | const unsigned int *timeouts = data; | |
1374 | ||
4925a459 DM |
1375 | if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT, |
1376 | htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) || | |
1377 | nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV, | |
1378 | htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) || | |
1379 | nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED, | |
1380 | htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) || | |
1381 | nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT, | |
1382 | htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) || | |
1383 | nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT, | |
1384 | htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) || | |
1385 | nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK, | |
1386 | htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) || | |
1387 | nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT, | |
1388 | htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) || | |
1389 | nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE, | |
1390 | htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) || | |
1391 | nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2, | |
1392 | htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) || | |
1393 | nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS, | |
1394 | htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) || | |
1395 | nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK, | |
1396 | htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ))) | |
1397 | goto nla_put_failure; | |
50978462 PNA |
1398 | return 0; |
1399 | ||
1400 | nla_put_failure: | |
1401 | return -ENOSPC; | |
1402 | } | |
1403 | ||
1404 | static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = { | |
1405 | [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 }, | |
1406 | [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 }, | |
1407 | [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 }, | |
1408 | [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 }, | |
1409 | [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 }, | |
1410 | [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 }, | |
1411 | [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 }, | |
1412 | [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 }, | |
1413 | [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 }, | |
6d1fafca FW |
1414 | [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 }, |
1415 | [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 }, | |
50978462 | 1416 | }; |
a874752a | 1417 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
50978462 | 1418 | |
2a389de8 | 1419 | void nf_conntrack_tcp_init_net(struct net *net) |
d2ba1fde | 1420 | { |
a95a7774 | 1421 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
2a389de8 | 1422 | int i; |
d2ba1fde | 1423 | |
2a389de8 FW |
1424 | for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++) |
1425 | tn->timeouts[i] = tcp_timeouts[i]; | |
d2ba1fde | 1426 | |
2a389de8 FW |
1427 | /* timeouts[0] is unused, make it same as SYN_SENT so |
1428 | * ->timeouts[0] contains 'new' timeout, like udp or icmp. | |
1429 | */ | |
1430 | tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT]; | |
1431 | tn->tcp_loose = nf_ct_tcp_loose; | |
1432 | tn->tcp_be_liberal = nf_ct_tcp_be_liberal; | |
1433 | tn->tcp_max_retrans = nf_ct_tcp_max_retrans; | |
08911475 PNA |
1434 | } |
1435 | ||
dd2934a9 | 1436 | const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp = |
9fb9cbb1 | 1437 | { |
605dcad6 | 1438 | .l4proto = IPPROTO_TCP, |
ea48cc83 | 1439 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
9fb9cbb1 | 1440 | .print_conntrack = tcp_print_conntrack, |
ea48cc83 | 1441 | #endif |
c6dd940b | 1442 | .can_early_drop = tcp_can_early_drop, |
c0cd1156 | 1443 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
fdf70832 PM |
1444 | .to_nlattr = tcp_to_nlattr, |
1445 | .from_nlattr = nlattr_to_tcp, | |
1446 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, | |
1447 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, | |
a400c30e | 1448 | .nlattr_tuple_size = tcp_nlattr_tuple_size, |
39215846 | 1449 | .nlattr_size = TCP_NLATTR_SIZE, |
f73e924c | 1450 | .nla_policy = nf_ct_port_nla_policy, |
c1d10adb | 1451 | #endif |
a874752a | 1452 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
1453 | .ctnl_timeout = { |
1454 | .nlattr_to_obj = tcp_timeout_nlattr_to_obj, | |
1455 | .obj_to_nlattr = tcp_timeout_obj_to_nlattr, | |
1456 | .nlattr_max = CTA_TIMEOUT_TCP_MAX, | |
1457 | .obj_size = sizeof(unsigned int) * | |
1458 | TCP_CONNTRACK_TIMEOUT_MAX, | |
1459 | .nla_policy = tcp_timeout_nla_policy, | |
1460 | }, | |
a874752a | 1461 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
9fb9cbb1 | 1462 | }; |