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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 | |
9fb9cbb1 YK |
34 | /* FIXME: Examine ipfilter's timeouts and conntrack transitions more |
35 | closely. They're more complex. --RR */ | |
36 | ||
82f568fc | 37 | static const char *const tcp_conntrack_names[] = { |
9fb9cbb1 YK |
38 | "NONE", |
39 | "SYN_SENT", | |
40 | "SYN_RECV", | |
41 | "ESTABLISHED", | |
42 | "FIN_WAIT", | |
43 | "CLOSE_WAIT", | |
44 | "LAST_ACK", | |
45 | "TIME_WAIT", | |
46 | "CLOSE", | |
874ab923 | 47 | "SYN_SENT2", |
9fb9cbb1 | 48 | }; |
601e68e1 | 49 | |
9fb9cbb1 YK |
50 | #define SECS * HZ |
51 | #define MINS * 60 SECS | |
52 | #define HOURS * 60 MINS | |
53 | #define DAYS * 24 HOURS | |
54 | ||
2c9e8637 | 55 | static const unsigned int tcp_timeouts[TCP_CONNTRACK_TIMEOUT_MAX] = { |
2d646286 PM |
56 | [TCP_CONNTRACK_SYN_SENT] = 2 MINS, |
57 | [TCP_CONNTRACK_SYN_RECV] = 60 SECS, | |
58 | [TCP_CONNTRACK_ESTABLISHED] = 5 DAYS, | |
59 | [TCP_CONNTRACK_FIN_WAIT] = 2 MINS, | |
60 | [TCP_CONNTRACK_CLOSE_WAIT] = 60 SECS, | |
61 | [TCP_CONNTRACK_LAST_ACK] = 30 SECS, | |
62 | [TCP_CONNTRACK_TIME_WAIT] = 2 MINS, | |
63 | [TCP_CONNTRACK_CLOSE] = 10 SECS, | |
874ab923 | 64 | [TCP_CONNTRACK_SYN_SENT2] = 2 MINS, |
33ee4464 PNA |
65 | /* RFC1122 says the R2 limit should be at least 100 seconds. |
66 | Linux uses 15 packets as limit, which corresponds | |
67 | to ~13-30min depending on RTO. */ | |
68 | [TCP_CONNTRACK_RETRANS] = 5 MINS, | |
69 | [TCP_CONNTRACK_UNACK] = 5 MINS, | |
2d646286 | 70 | }; |
601e68e1 | 71 | |
9fb9cbb1 YK |
72 | #define sNO TCP_CONNTRACK_NONE |
73 | #define sSS TCP_CONNTRACK_SYN_SENT | |
74 | #define sSR TCP_CONNTRACK_SYN_RECV | |
75 | #define sES TCP_CONNTRACK_ESTABLISHED | |
76 | #define sFW TCP_CONNTRACK_FIN_WAIT | |
77 | #define sCW TCP_CONNTRACK_CLOSE_WAIT | |
78 | #define sLA TCP_CONNTRACK_LAST_ACK | |
79 | #define sTW TCP_CONNTRACK_TIME_WAIT | |
80 | #define sCL TCP_CONNTRACK_CLOSE | |
874ab923 | 81 | #define sS2 TCP_CONNTRACK_SYN_SENT2 |
9fb9cbb1 YK |
82 | #define sIV TCP_CONNTRACK_MAX |
83 | #define sIG TCP_CONNTRACK_IGNORE | |
84 | ||
85 | /* What TCP flags are set from RST/SYN/FIN/ACK. */ | |
86 | enum tcp_bit_set { | |
87 | TCP_SYN_SET, | |
88 | TCP_SYNACK_SET, | |
89 | TCP_FIN_SET, | |
90 | TCP_ACK_SET, | |
91 | TCP_RST_SET, | |
92 | TCP_NONE_SET, | |
93 | }; | |
601e68e1 | 94 | |
9fb9cbb1 YK |
95 | /* |
96 | * The TCP state transition table needs a few words... | |
97 | * | |
98 | * We are the man in the middle. All the packets go through us | |
99 | * but might get lost in transit to the destination. | |
601e68e1 | 100 | * It is assumed that the destinations can't receive segments |
9fb9cbb1 YK |
101 | * we haven't seen. |
102 | * | |
103 | * The checked segment is in window, but our windows are *not* | |
104 | * equivalent with the ones of the sender/receiver. We always | |
105 | * try to guess the state of the current sender. | |
106 | * | |
107 | * The meaning of the states are: | |
108 | * | |
109 | * NONE: initial state | |
601e68e1 | 110 | * SYN_SENT: SYN-only packet seen |
874ab923 | 111 | * SYN_SENT2: SYN-only packet seen from reply dir, simultaneous open |
9fb9cbb1 YK |
112 | * SYN_RECV: SYN-ACK packet seen |
113 | * ESTABLISHED: ACK packet seen | |
114 | * FIN_WAIT: FIN packet seen | |
601e68e1 | 115 | * CLOSE_WAIT: ACK seen (after FIN) |
9fb9cbb1 YK |
116 | * LAST_ACK: FIN seen (after FIN) |
117 | * TIME_WAIT: last ACK seen | |
b2155e7f | 118 | * CLOSE: closed connection (RST) |
9fb9cbb1 | 119 | * |
9fb9cbb1 | 120 | * Packets marked as IGNORED (sIG): |
601e68e1 YH |
121 | * if they may be either invalid or valid |
122 | * and the receiver may send back a connection | |
9fb9cbb1 YK |
123 | * closing RST or a SYN/ACK. |
124 | * | |
125 | * Packets marked as INVALID (sIV): | |
874ab923 | 126 | * if we regard them as truly invalid packets |
9fb9cbb1 | 127 | */ |
a5e73c29 | 128 | static const u8 tcp_conntracks[2][6][TCP_CONNTRACK_MAX] = { |
9fb9cbb1 YK |
129 | { |
130 | /* ORIGINAL */ | |
874ab923 JK |
131 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
132 | /*syn*/ { sSS, sSS, sIG, sIG, sIG, sIG, sIG, sSS, sSS, sS2 }, | |
9fb9cbb1 YK |
133 | /* |
134 | * sNO -> sSS Initialize a new connection | |
135 | * sSS -> sSS Retransmitted SYN | |
874ab923 JK |
136 | * sS2 -> sS2 Late retransmitted SYN |
137 | * sSR -> sIG | |
9fb9cbb1 | 138 | * sES -> sIG Error: SYNs in window outside the SYN_SENT state |
601e68e1 | 139 | * are errors. Receiver will reply with RST |
9fb9cbb1 YK |
140 | * and close the connection. |
141 | * Or we are not in sync and hold a dead connection. | |
142 | * sFW -> sIG | |
143 | * sCW -> sIG | |
144 | * sLA -> sIG | |
145 | * sTW -> sSS Reopened connection (RFC 1122). | |
146 | * sCL -> sSS | |
147 | */ | |
874ab923 | 148 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
64f509ce | 149 | /*synack*/ { sIV, sIV, sSR, sIV, sIV, sIV, sIV, sIV, sIV, sSR }, |
9fb9cbb1 | 150 | /* |
874ab923 JK |
151 | * sNO -> sIV Too late and no reason to do anything |
152 | * sSS -> sIV Client can't send SYN and then SYN/ACK | |
153 | * sS2 -> sSR SYN/ACK sent to SYN2 in simultaneous open | |
64f509ce JK |
154 | * sSR -> sSR Late retransmitted SYN/ACK in simultaneous open |
155 | * sES -> sIV Invalid SYN/ACK packets sent by the client | |
156 | * sFW -> sIV | |
157 | * sCW -> sIV | |
158 | * sLA -> sIV | |
159 | * sTW -> sIV | |
160 | * sCL -> sIV | |
9fb9cbb1 | 161 | */ |
874ab923 | 162 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
163 | /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
164 | /* | |
165 | * sNO -> sIV Too late and no reason to do anything... | |
166 | * sSS -> sIV Client migth not send FIN in this state: | |
167 | * we enforce waiting for a SYN/ACK reply first. | |
874ab923 | 168 | * sS2 -> sIV |
9fb9cbb1 YK |
169 | * sSR -> sFW Close started. |
170 | * sES -> sFW | |
171 | * sFW -> sLA FIN seen in both directions, waiting for | |
601e68e1 | 172 | * the last ACK. |
9fb9cbb1 YK |
173 | * Migth be a retransmitted FIN as well... |
174 | * sCW -> sLA | |
175 | * sLA -> sLA Retransmitted FIN. Remain in the same state. | |
176 | * sTW -> sTW | |
177 | * sCL -> sCL | |
178 | */ | |
874ab923 | 179 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
180 | /*ack*/ { sES, sIV, sES, sES, sCW, sCW, sTW, sTW, sCL, sIV }, |
181 | /* | |
182 | * sNO -> sES Assumed. | |
183 | * sSS -> sIV ACK is invalid: we haven't seen a SYN/ACK yet. | |
874ab923 | 184 | * sS2 -> sIV |
9fb9cbb1 YK |
185 | * sSR -> sES Established state is reached. |
186 | * sES -> sES :-) | |
187 | * sFW -> sCW Normal close request answered by ACK. | |
188 | * sCW -> sCW | |
b3cad287 | 189 | * sLA -> sTW Last ACK detected (RFC5961 challenged) |
9fb9cbb1 YK |
190 | * sTW -> sTW Retransmitted last ACK. Remain in the same state. |
191 | * sCL -> sCL | |
192 | */ | |
874ab923 JK |
193 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
194 | /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, | |
9fb9cbb1 YK |
195 | /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
196 | }, | |
197 | { | |
198 | /* REPLY */ | |
874ab923 | 199 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
e37ad9fd | 200 | /*syn*/ { sIV, sS2, sIV, sIV, sIV, sIV, sIV, sSS, sIV, sS2 }, |
9fb9cbb1 YK |
201 | /* |
202 | * sNO -> sIV Never reached. | |
874ab923 JK |
203 | * sSS -> sS2 Simultaneous open |
204 | * sS2 -> sS2 Retransmitted simultaneous SYN | |
205 | * sSR -> sIV Invalid SYN packets sent by the server | |
206 | * sES -> sIV | |
9fb9cbb1 YK |
207 | * sFW -> sIV |
208 | * sCW -> sIV | |
209 | * sLA -> sIV | |
e37ad9fd | 210 | * sTW -> sSS Reopened connection, but server may have switched role |
9fb9cbb1 YK |
211 | * sCL -> sIV |
212 | */ | |
874ab923 | 213 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
8a80c79a | 214 | /*synack*/ { sIV, sSR, sIG, sIG, sIG, sIG, sIG, sIG, sIG, sSR }, |
9fb9cbb1 YK |
215 | /* |
216 | * sSS -> sSR Standard open. | |
874ab923 | 217 | * sS2 -> sSR Simultaneous open |
8a80c79a | 218 | * sSR -> sIG Retransmitted SYN/ACK, ignore it. |
9fb9cbb1 YK |
219 | * sES -> sIG Late retransmitted SYN/ACK? |
220 | * sFW -> sIG Might be SYN/ACK answering ignored SYN | |
221 | * sCW -> sIG | |
222 | * sLA -> sIG | |
223 | * sTW -> sIG | |
224 | * sCL -> sIG | |
225 | */ | |
874ab923 | 226 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
9fb9cbb1 YK |
227 | /*fin*/ { sIV, sIV, sFW, sFW, sLA, sLA, sLA, sTW, sCL, sIV }, |
228 | /* | |
229 | * sSS -> sIV Server might not send FIN in this state. | |
874ab923 | 230 | * sS2 -> sIV |
9fb9cbb1 YK |
231 | * sSR -> sFW Close started. |
232 | * sES -> sFW | |
233 | * sFW -> sLA FIN seen in both directions. | |
234 | * sCW -> sLA | |
235 | * sLA -> sLA Retransmitted FIN. | |
236 | * sTW -> sTW | |
237 | * sCL -> sCL | |
238 | */ | |
874ab923 JK |
239 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
240 | /*ack*/ { sIV, sIG, sSR, sES, sCW, sCW, sTW, sTW, sCL, sIG }, | |
9fb9cbb1 | 241 | /* |
73f30602 | 242 | * sSS -> sIG Might be a half-open connection. |
874ab923 | 243 | * sS2 -> sIG |
9fb9cbb1 YK |
244 | * sSR -> sSR Might answer late resent SYN. |
245 | * sES -> sES :-) | |
246 | * sFW -> sCW Normal close request answered by ACK. | |
247 | * sCW -> sCW | |
b3cad287 | 248 | * sLA -> sTW Last ACK detected (RFC5961 challenged) |
9fb9cbb1 YK |
249 | * sTW -> sTW Retransmitted last ACK. |
250 | * sCL -> sCL | |
251 | */ | |
874ab923 JK |
252 | /* sNO, sSS, sSR, sES, sFW, sCW, sLA, sTW, sCL, sS2 */ |
253 | /*rst*/ { sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL }, | |
9fb9cbb1 | 254 | /*none*/ { sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV } |
601e68e1 | 255 | } |
9fb9cbb1 YK |
256 | }; |
257 | ||
ea48cc83 | 258 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
9fb9cbb1 | 259 | /* Print out the private part of the conntrack. */ |
37246a58 | 260 | static void tcp_print_conntrack(struct seq_file *s, struct nf_conn *ct) |
9fb9cbb1 | 261 | { |
90964016 PNA |
262 | if (test_bit(IPS_OFFLOAD_BIT, &ct->status)) |
263 | return; | |
264 | ||
a163f2cb | 265 | seq_printf(s, "%s ", tcp_conntrack_names[ct->proto.tcp.state]); |
9fb9cbb1 | 266 | } |
ea48cc83 | 267 | #endif |
9fb9cbb1 YK |
268 | |
269 | static unsigned int get_conntrack_index(const struct tcphdr *tcph) | |
270 | { | |
271 | if (tcph->rst) return TCP_RST_SET; | |
272 | else if (tcph->syn) return (tcph->ack ? TCP_SYNACK_SET : TCP_SYN_SET); | |
273 | else if (tcph->fin) return TCP_FIN_SET; | |
274 | else if (tcph->ack) return TCP_ACK_SET; | |
275 | else return TCP_NONE_SET; | |
276 | } | |
277 | ||
278 | /* TCP connection tracking based on 'Real Stateful TCP Packet Filtering | |
279 | in IP Filter' by Guido van Rooij. | |
601e68e1 | 280 | |
631dd1a8 JM |
281 | http://www.sane.nl/events/sane2000/papers.html |
282 | http://www.darkart.com/mirrors/www.obfuscation.org/ipf/ | |
601e68e1 | 283 | |
9fb9cbb1 YK |
284 | The boundaries and the conditions are changed according to RFC793: |
285 | the packet must intersect the window (i.e. segments may be | |
286 | after the right or before the left edge) and thus receivers may ACK | |
287 | segments after the right edge of the window. | |
288 | ||
601e68e1 | 289 | td_maxend = max(sack + max(win,1)) seen in reply packets |
9fb9cbb1 YK |
290 | td_maxwin = max(max(win, 1)) + (sack - ack) seen in sent packets |
291 | td_maxwin += seq + len - sender.td_maxend | |
292 | if seq + len > sender.td_maxend | |
293 | td_end = max(seq + len) seen in sent packets | |
601e68e1 | 294 | |
9fb9cbb1 YK |
295 | I. Upper bound for valid data: seq <= sender.td_maxend |
296 | II. Lower bound for valid data: seq + len >= sender.td_end - receiver.td_maxwin | |
84ebe1cd JK |
297 | III. Upper bound for valid (s)ack: sack <= receiver.td_end |
298 | IV. Lower bound for valid (s)ack: sack >= receiver.td_end - MAXACKWINDOW | |
9fb9cbb1 | 299 | |
84ebe1cd JK |
300 | where sack is the highest right edge of sack block found in the packet |
301 | or ack in the case of packet without SACK option. | |
9fb9cbb1 | 302 | |
84ebe1cd | 303 | The upper bound limit for a valid (s)ack is not ignored - |
601e68e1 | 304 | we doesn't have to deal with fragments. |
9fb9cbb1 YK |
305 | */ |
306 | ||
307 | static inline __u32 segment_seq_plus_len(__u32 seq, | |
308 | size_t len, | |
309 | unsigned int dataoff, | |
82f568fc | 310 | const struct tcphdr *tcph) |
9fb9cbb1 YK |
311 | { |
312 | /* XXX Should I use payload length field in IP/IPv6 header ? | |
313 | * - YK */ | |
314 | return (seq + len - dataoff - tcph->doff*4 | |
315 | + (tcph->syn ? 1 : 0) + (tcph->fin ? 1 : 0)); | |
316 | } | |
601e68e1 | 317 | |
9fb9cbb1 YK |
318 | /* Fixme: what about big packets? */ |
319 | #define MAXACKWINCONST 66000 | |
320 | #define MAXACKWINDOW(sender) \ | |
321 | ((sender)->td_maxwin > MAXACKWINCONST ? (sender)->td_maxwin \ | |
322 | : MAXACKWINCONST) | |
601e68e1 | 323 | |
9fb9cbb1 YK |
324 | /* |
325 | * Simplified tcp_parse_options routine from tcp_input.c | |
326 | */ | |
327 | static void tcp_options(const struct sk_buff *skb, | |
328 | unsigned int dataoff, | |
82f568fc | 329 | const struct tcphdr *tcph, |
9fb9cbb1 YK |
330 | struct ip_ct_tcp_state *state) |
331 | { | |
332 | unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; | |
82f568fc | 333 | const unsigned char *ptr; |
9fb9cbb1 YK |
334 | int length = (tcph->doff*4) - sizeof(struct tcphdr); |
335 | ||
336 | if (!length) | |
337 | return; | |
338 | ||
339 | ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), | |
340 | length, buff); | |
198ad973 PNA |
341 | if (!ptr) |
342 | return; | |
9fb9cbb1 | 343 | |
601e68e1 | 344 | state->td_scale = |
9fb9cbb1 YK |
345 | state->flags = 0; |
346 | ||
347 | while (length > 0) { | |
348 | int opcode=*ptr++; | |
349 | int opsize; | |
350 | ||
351 | switch (opcode) { | |
352 | case TCPOPT_EOL: | |
353 | return; | |
354 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
355 | length--; | |
356 | continue; | |
357 | default: | |
644c7e48 JK |
358 | if (length < 2) |
359 | return; | |
9fb9cbb1 YK |
360 | opsize=*ptr++; |
361 | if (opsize < 2) /* "silly options" */ | |
362 | return; | |
363 | if (opsize > length) | |
4a5cc84a | 364 | return; /* don't parse partial options */ |
9fb9cbb1 | 365 | |
601e68e1 | 366 | if (opcode == TCPOPT_SACK_PERM |
9fb9cbb1 YK |
367 | && opsize == TCPOLEN_SACK_PERM) |
368 | state->flags |= IP_CT_TCP_FLAG_SACK_PERM; | |
369 | else if (opcode == TCPOPT_WINDOW | |
370 | && opsize == TCPOLEN_WINDOW) { | |
371 | state->td_scale = *(u_int8_t *)ptr; | |
372 | ||
122868b3 GF |
373 | if (state->td_scale > TCP_MAX_WSCALE) |
374 | state->td_scale = TCP_MAX_WSCALE; | |
375 | ||
9fb9cbb1 YK |
376 | state->flags |= |
377 | IP_CT_TCP_FLAG_WINDOW_SCALE; | |
378 | } | |
379 | ptr += opsize - 2; | |
380 | length -= opsize; | |
381 | } | |
382 | } | |
383 | } | |
384 | ||
385 | static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff, | |
82f568fc | 386 | const struct tcphdr *tcph, __u32 *sack) |
9fb9cbb1 | 387 | { |
601e68e1 | 388 | unsigned char buff[(15 * 4) - sizeof(struct tcphdr)]; |
82f568fc | 389 | const unsigned char *ptr; |
9fb9cbb1 YK |
390 | int length = (tcph->doff*4) - sizeof(struct tcphdr); |
391 | __u32 tmp; | |
392 | ||
393 | if (!length) | |
394 | return; | |
395 | ||
396 | ptr = skb_header_pointer(skb, dataoff + sizeof(struct tcphdr), | |
397 | length, buff); | |
198ad973 PNA |
398 | if (!ptr) |
399 | return; | |
9fb9cbb1 YK |
400 | |
401 | /* Fast path for timestamp-only option */ | |
bb9fc373 | 402 | if (length == TCPOLEN_TSTAMP_ALIGNED |
8f05ce91 YH |
403 | && *(__be32 *)ptr == htonl((TCPOPT_NOP << 24) |
404 | | (TCPOPT_NOP << 16) | |
405 | | (TCPOPT_TIMESTAMP << 8) | |
406 | | TCPOLEN_TIMESTAMP)) | |
9fb9cbb1 YK |
407 | return; |
408 | ||
409 | while (length > 0) { | |
410 | int opcode = *ptr++; | |
411 | int opsize, i; | |
412 | ||
413 | switch (opcode) { | |
414 | case TCPOPT_EOL: | |
415 | return; | |
416 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ | |
417 | length--; | |
418 | continue; | |
419 | default: | |
644c7e48 JK |
420 | if (length < 2) |
421 | return; | |
9fb9cbb1 YK |
422 | opsize = *ptr++; |
423 | if (opsize < 2) /* "silly options" */ | |
424 | return; | |
425 | if (opsize > length) | |
4a5cc84a | 426 | return; /* don't parse partial options */ |
9fb9cbb1 | 427 | |
601e68e1 YH |
428 | if (opcode == TCPOPT_SACK |
429 | && opsize >= (TCPOLEN_SACK_BASE | |
430 | + TCPOLEN_SACK_PERBLOCK) | |
431 | && !((opsize - TCPOLEN_SACK_BASE) | |
432 | % TCPOLEN_SACK_PERBLOCK)) { | |
433 | for (i = 0; | |
434 | i < (opsize - TCPOLEN_SACK_BASE); | |
435 | i += TCPOLEN_SACK_PERBLOCK) { | |
534f81a5 | 436 | tmp = get_unaligned_be32((__be32 *)(ptr+i)+1); |
9fb9cbb1 YK |
437 | |
438 | if (after(tmp, *sack)) | |
439 | *sack = tmp; | |
440 | } | |
441 | return; | |
442 | } | |
443 | ptr += opsize - 2; | |
444 | length -= opsize; | |
445 | } | |
446 | } | |
447 | } | |
448 | ||
cc4f9d62 FW |
449 | static void tcp_init_sender(struct ip_ct_tcp_state *sender, |
450 | struct ip_ct_tcp_state *receiver, | |
451 | const struct sk_buff *skb, | |
452 | unsigned int dataoff, | |
453 | const struct tcphdr *tcph, | |
454 | u32 end, u32 win) | |
455 | { | |
456 | /* SYN-ACK in reply to a SYN | |
457 | * or SYN from reply direction in simultaneous open. | |
458 | */ | |
459 | sender->td_end = | |
460 | sender->td_maxend = end; | |
461 | sender->td_maxwin = (win == 0 ? 1 : win); | |
462 | ||
463 | tcp_options(skb, dataoff, tcph, sender); | |
464 | /* RFC 1323: | |
465 | * Both sides must send the Window Scale option | |
466 | * to enable window scaling in either direction. | |
467 | */ | |
468 | if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE && | |
469 | receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) { | |
470 | sender->td_scale = 0; | |
471 | receiver->td_scale = 0; | |
472 | } | |
473 | } | |
474 | ||
62eec0d7 | 475 | static bool tcp_in_window(struct nf_conn *ct, |
09f263cd JE |
476 | enum ip_conntrack_dir dir, |
477 | unsigned int index, | |
478 | const struct sk_buff *skb, | |
479 | unsigned int dataoff, | |
62eec0d7 FW |
480 | const struct tcphdr *tcph, |
481 | const struct nf_hook_state *hook_state) | |
9fb9cbb1 | 482 | { |
62eec0d7 | 483 | struct ip_ct_tcp *state = &ct->proto.tcp; |
c2a2c7e0 | 484 | struct net *net = nf_ct_net(ct); |
a95a7774 | 485 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
9fb9cbb1 YK |
486 | struct ip_ct_tcp_state *sender = &state->seen[dir]; |
487 | struct ip_ct_tcp_state *receiver = &state->seen[!dir]; | |
82f568fc | 488 | const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple; |
9fb9cbb1 | 489 | __u32 seq, ack, sack, end, win, swin; |
959b69ef | 490 | u16 win_raw; |
2d89c68a | 491 | s32 receiver_offset; |
356d7d88 | 492 | bool res, in_recv_win; |
9fb9cbb1 YK |
493 | |
494 | /* | |
495 | * Get the required data from the packet. | |
496 | */ | |
497 | seq = ntohl(tcph->seq); | |
498 | ack = sack = ntohl(tcph->ack_seq); | |
959b69ef FW |
499 | win_raw = ntohs(tcph->window); |
500 | win = win_raw; | |
9fb9cbb1 YK |
501 | end = segment_seq_plus_len(seq, skb->len, dataoff, tcph); |
502 | ||
503 | if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM) | |
504 | tcp_sack(skb, dataoff, tcph, &sack); | |
505 | ||
f9dd09c7 | 506 | /* Take into account NAT sequence number mangling */ |
41d73ec0 | 507 | receiver_offset = nf_ct_seq_offset(ct, !dir, ack - 1); |
f9dd09c7 JK |
508 | ack -= receiver_offset; |
509 | sack -= receiver_offset; | |
510 | ||
0d53778e PM |
511 | pr_debug("tcp_in_window: START\n"); |
512 | pr_debug("tcp_in_window: "); | |
3c9fba65 | 513 | nf_ct_dump_tuple(tuple); |
f9dd09c7 JK |
514 | pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
515 | seq, ack, receiver_offset, sack, receiver_offset, win, end); | |
0d53778e PM |
516 | pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
517 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
518 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
519 | sender->td_scale, | |
520 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
521 | receiver->td_scale); | |
9fb9cbb1 | 522 | |
874ab923 | 523 | if (sender->td_maxwin == 0) { |
9fb9cbb1 YK |
524 | /* |
525 | * Initialize sender data. | |
526 | */ | |
874ab923 | 527 | if (tcph->syn) { |
cc4f9d62 FW |
528 | tcp_init_sender(sender, receiver, |
529 | skb, dataoff, tcph, | |
530 | end, win); | |
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; |
4f25434b FR |
544 | if (receiver->td_maxwin == 0) { |
545 | /* We haven't seen traffic in the other | |
546 | * direction yet but we have to tweak window | |
547 | * tracking to pass III and IV until that | |
548 | * happens. | |
549 | */ | |
fac42a9a | 550 | receiver->td_end = receiver->td_maxend = sack; |
4f25434b FR |
551 | } else if (sack == receiver->td_end + 1) { |
552 | /* Likely a reply to a keepalive. | |
553 | * Needed for III. | |
554 | */ | |
555 | receiver->td_end++; | |
556 | } | |
557 | ||
9fb9cbb1 YK |
558 | } |
559 | } else if (((state->state == TCP_CONNTRACK_SYN_SENT | |
560 | && dir == IP_CT_DIR_ORIGINAL) | |
561 | || (state->state == TCP_CONNTRACK_SYN_RECV | |
562 | && dir == IP_CT_DIR_REPLY)) | |
563 | && after(end, sender->td_end)) { | |
564 | /* | |
565 | * RFC 793: "if a TCP is reinitialized ... then it need | |
601e68e1 | 566 | * not wait at all; it must only be sure to use sequence |
9fb9cbb1 YK |
567 | * numbers larger than those recently used." |
568 | */ | |
569 | sender->td_end = | |
570 | sender->td_maxend = end; | |
571 | sender->td_maxwin = (win == 0 ? 1 : win); | |
572 | ||
573 | tcp_options(skb, dataoff, tcph, sender); | |
82b72cb9 FW |
574 | } else if (tcph->syn && dir == IP_CT_DIR_REPLY && |
575 | state->state == TCP_CONNTRACK_SYN_SENT) { | |
576 | /* Retransmitted syn-ack, or syn (simultaneous open). | |
577 | * | |
578 | * Re-init state for this direction, just like for the first | |
579 | * syn(-ack) reply, it might differ in seq, ack or tcp options. | |
580 | */ | |
581 | tcp_init_sender(sender, receiver, | |
582 | skb, dataoff, tcph, | |
583 | end, win); | |
584 | if (!tcph->ack) | |
585 | return true; | |
9fb9cbb1 YK |
586 | } |
587 | ||
588 | if (!(tcph->ack)) { | |
589 | /* | |
590 | * If there is no ACK, just pretend it was set and OK. | |
591 | */ | |
592 | ack = sack = receiver->td_end; | |
601e68e1 YH |
593 | } else if (((tcp_flag_word(tcph) & (TCP_FLAG_ACK|TCP_FLAG_RST)) == |
594 | (TCP_FLAG_ACK|TCP_FLAG_RST)) | |
9fb9cbb1 YK |
595 | && (ack == 0)) { |
596 | /* | |
597 | * Broken TCP stacks, that set ACK in RST packets as well | |
598 | * with zero ack value. | |
599 | */ | |
600 | ack = sack = receiver->td_end; | |
601 | } | |
602 | ||
4a70bbfa | 603 | if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT) |
9fb9cbb1 | 604 | /* |
4a70bbfa | 605 | * RST sent answering SYN. |
9fb9cbb1 YK |
606 | */ |
607 | seq = end = sender->td_end; | |
608 | ||
0d53778e | 609 | pr_debug("tcp_in_window: "); |
3c9fba65 | 610 | nf_ct_dump_tuple(tuple); |
f9dd09c7 JK |
611 | pr_debug("seq=%u ack=%u+(%d) sack=%u+(%d) win=%u end=%u\n", |
612 | seq, ack, receiver_offset, sack, receiver_offset, win, end); | |
0d53778e PM |
613 | pr_debug("tcp_in_window: sender end=%u maxend=%u maxwin=%u scale=%i " |
614 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
615 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
616 | sender->td_scale, | |
617 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
618 | receiver->td_scale); | |
619 | ||
356d7d88 YC |
620 | /* Is the ending sequence in the receive window (if available)? */ |
621 | in_recv_win = !receiver->td_maxwin || | |
622 | after(end, sender->td_end - receiver->td_maxwin - 1); | |
623 | ||
0d53778e PM |
624 | pr_debug("tcp_in_window: I=%i II=%i III=%i IV=%i\n", |
625 | before(seq, sender->td_maxend + 1), | |
356d7d88 | 626 | (in_recv_win ? 1 : 0), |
0d53778e | 627 | before(sack, receiver->td_end + 1), |
84ebe1cd | 628 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)); |
9fb9cbb1 | 629 | |
a09113c2 | 630 | if (before(seq, sender->td_maxend + 1) && |
356d7d88 | 631 | in_recv_win && |
a09113c2 | 632 | before(sack, receiver->td_end + 1) && |
84ebe1cd | 633 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1)) { |
601e68e1 | 634 | /* |
9fb9cbb1 YK |
635 | * Take into account window scaling (RFC 1323). |
636 | */ | |
637 | if (!tcph->syn) | |
638 | win <<= sender->td_scale; | |
639 | ||
640 | /* | |
641 | * Update sender data. | |
642 | */ | |
643 | swin = win + (sack - ack); | |
644 | if (sender->td_maxwin < swin) | |
645 | sender->td_maxwin = swin; | |
ae375044 | 646 | if (after(end, sender->td_end)) { |
9fb9cbb1 | 647 | sender->td_end = end; |
ae375044 PM |
648 | sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; |
649 | } | |
bfcaa502 JK |
650 | if (tcph->ack) { |
651 | if (!(sender->flags & IP_CT_TCP_FLAG_MAXACK_SET)) { | |
652 | sender->td_maxack = ack; | |
653 | sender->flags |= IP_CT_TCP_FLAG_MAXACK_SET; | |
654 | } else if (after(ack, sender->td_maxack)) | |
655 | sender->td_maxack = ack; | |
656 | } | |
657 | ||
9fb9cbb1 YK |
658 | /* |
659 | * Update receiver data. | |
660 | */ | |
fac42a9a | 661 | if (receiver->td_maxwin != 0 && after(end, sender->td_maxend)) |
9fb9cbb1 YK |
662 | receiver->td_maxwin += end - sender->td_maxend; |
663 | if (after(sack + win, receiver->td_maxend - 1)) { | |
664 | receiver->td_maxend = sack + win; | |
665 | if (win == 0) | |
666 | receiver->td_maxend++; | |
667 | } | |
ae375044 PM |
668 | if (ack == receiver->td_end) |
669 | receiver->flags &= ~IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; | |
9fb9cbb1 | 670 | |
601e68e1 | 671 | /* |
9fb9cbb1 YK |
672 | * Check retransmissions. |
673 | */ | |
674 | if (index == TCP_ACK_SET) { | |
675 | if (state->last_dir == dir | |
676 | && state->last_seq == seq | |
677 | && state->last_ack == ack | |
c1fe3ca5 | 678 | && state->last_end == end |
959b69ef | 679 | && state->last_win == win_raw) |
9fb9cbb1 YK |
680 | state->retrans++; |
681 | else { | |
682 | state->last_dir = dir; | |
683 | state->last_seq = seq; | |
684 | state->last_ack = ack; | |
685 | state->last_end = end; | |
959b69ef | 686 | state->last_win = win_raw; |
9fb9cbb1 YK |
687 | state->retrans = 0; |
688 | } | |
689 | } | |
09f263cd | 690 | res = true; |
9fb9cbb1 | 691 | } else { |
09f263cd | 692 | res = false; |
a09113c2 | 693 | if (sender->flags & IP_CT_TCP_FLAG_BE_LIBERAL || |
d2ba1fde | 694 | tn->tcp_be_liberal) |
09f263cd | 695 | res = true; |
3d0b527b | 696 | if (!res) { |
62eec0d7 | 697 | nf_ct_l4proto_log_invalid(skb, ct, hook_state, |
3d0b527b | 698 | "%s", |
9fb9cbb1 | 699 | before(seq, sender->td_maxend + 1) ? |
356d7d88 | 700 | in_recv_win ? |
9fb9cbb1 | 701 | before(sack, receiver->td_end + 1) ? |
f9dd09c7 | 702 | after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1) ? "BUG" |
9fb9cbb1 YK |
703 | : "ACK is under the lower bound (possible overly delayed ACK)" |
704 | : "ACK is over the upper bound (ACKed data not seen yet)" | |
705 | : "SEQ is under the lower bound (already ACKed data retransmitted)" | |
706 | : "SEQ is over the upper bound (over the window of the receiver)"); | |
3d0b527b | 707 | } |
601e68e1 YH |
708 | } |
709 | ||
09f263cd | 710 | pr_debug("tcp_in_window: res=%u sender end=%u maxend=%u maxwin=%u " |
0d53778e PM |
711 | "receiver end=%u maxend=%u maxwin=%u\n", |
712 | res, sender->td_end, sender->td_maxend, sender->td_maxwin, | |
713 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin); | |
9fb9cbb1 YK |
714 | |
715 | return res; | |
716 | } | |
717 | ||
5c8ce7c9 | 718 | /* table of valid flag combinations - PUSH, ECE and CWR are always valid */ |
a3433f35 CG |
719 | static const u8 tcp_valid_flags[(TCPHDR_FIN|TCPHDR_SYN|TCPHDR_RST|TCPHDR_ACK| |
720 | TCPHDR_URG) + 1] = | |
9fb9cbb1 | 721 | { |
a3433f35 CG |
722 | [TCPHDR_SYN] = 1, |
723 | [TCPHDR_SYN|TCPHDR_URG] = 1, | |
724 | [TCPHDR_SYN|TCPHDR_ACK] = 1, | |
725 | [TCPHDR_RST] = 1, | |
726 | [TCPHDR_RST|TCPHDR_ACK] = 1, | |
727 | [TCPHDR_FIN|TCPHDR_ACK] = 1, | |
728 | [TCPHDR_FIN|TCPHDR_ACK|TCPHDR_URG] = 1, | |
729 | [TCPHDR_ACK] = 1, | |
730 | [TCPHDR_ACK|TCPHDR_URG] = 1, | |
9fb9cbb1 YK |
731 | }; |
732 | ||
93e66024 FW |
733 | static void tcp_error_log(const struct sk_buff *skb, |
734 | const struct nf_hook_state *state, | |
735 | const char *msg) | |
c4f3db15 | 736 | { |
62eec0d7 | 737 | nf_l4proto_log_invalid(skb, state, IPPROTO_TCP, "%s", msg); |
c4f3db15 FW |
738 | } |
739 | ||
9fb9cbb1 | 740 | /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c. */ |
0150ffba FW |
741 | static bool tcp_error(const struct tcphdr *th, |
742 | struct sk_buff *skb, | |
743 | unsigned int dataoff, | |
744 | const struct nf_hook_state *state) | |
9fb9cbb1 | 745 | { |
9fb9cbb1 | 746 | unsigned int tcplen = skb->len - dataoff; |
0150ffba | 747 | u8 tcpflags; |
601e68e1 | 748 | |
9fb9cbb1 YK |
749 | /* Not whole TCP header or malformed packet */ |
750 | if (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) { | |
93e66024 | 751 | tcp_error_log(skb, state, "truncated packet"); |
0150ffba | 752 | return true; |
9fb9cbb1 | 753 | } |
601e68e1 | 754 | |
9fb9cbb1 YK |
755 | /* Checksum invalid? Ignore. |
756 | * We skip checking packets on the outgoing path | |
84fa7933 | 757 | * because the checksum is assumed to be correct. |
9fb9cbb1 YK |
758 | */ |
759 | /* FIXME: Source route IP option packets --RR */ | |
93e66024 FW |
760 | if (state->net->ct.sysctl_checksum && |
761 | state->hook == NF_INET_PRE_ROUTING && | |
762 | nf_checksum(skb, state->hook, dataoff, IPPROTO_TCP, state->pf)) { | |
763 | tcp_error_log(skb, state, "bad checksum"); | |
0150ffba | 764 | return true; |
9fb9cbb1 YK |
765 | } |
766 | ||
767 | /* Check TCP flags. */ | |
a3433f35 | 768 | tcpflags = (tcp_flag_byte(th) & ~(TCPHDR_ECE|TCPHDR_CWR|TCPHDR_PSH)); |
9fb9cbb1 | 769 | if (!tcp_valid_flags[tcpflags]) { |
93e66024 | 770 | tcp_error_log(skb, state, "invalid tcp flag combination"); |
0150ffba | 771 | return true; |
9fb9cbb1 YK |
772 | } |
773 | ||
0150ffba | 774 | return false; |
9fb9cbb1 YK |
775 | } |
776 | ||
9976fc6e FW |
777 | static noinline bool tcp_new(struct nf_conn *ct, const struct sk_buff *skb, |
778 | unsigned int dataoff, | |
779 | const struct tcphdr *th) | |
780 | { | |
781 | enum tcp_conntrack new_state; | |
782 | struct net *net = nf_ct_net(ct); | |
a95a7774 | 783 | const struct nf_tcp_net *tn = nf_tcp_pernet(net); |
9976fc6e FW |
784 | const struct ip_ct_tcp_state *sender = &ct->proto.tcp.seen[0]; |
785 | const struct ip_ct_tcp_state *receiver = &ct->proto.tcp.seen[1]; | |
786 | ||
787 | /* Don't need lock here: this conntrack not in circulation yet */ | |
788 | new_state = tcp_conntracks[0][get_conntrack_index(th)][TCP_CONNTRACK_NONE]; | |
789 | ||
790 | /* Invalid: delete conntrack */ | |
791 | if (new_state >= TCP_CONNTRACK_MAX) { | |
792 | pr_debug("nf_ct_tcp: invalid new deleting.\n"); | |
793 | return false; | |
794 | } | |
795 | ||
796 | if (new_state == TCP_CONNTRACK_SYN_SENT) { | |
797 | memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); | |
798 | /* SYN packet */ | |
799 | ct->proto.tcp.seen[0].td_end = | |
800 | segment_seq_plus_len(ntohl(th->seq), skb->len, | |
801 | dataoff, th); | |
802 | ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); | |
803 | if (ct->proto.tcp.seen[0].td_maxwin == 0) | |
804 | ct->proto.tcp.seen[0].td_maxwin = 1; | |
805 | ct->proto.tcp.seen[0].td_maxend = | |
806 | ct->proto.tcp.seen[0].td_end; | |
807 | ||
808 | tcp_options(skb, dataoff, th, &ct->proto.tcp.seen[0]); | |
809 | } else if (tn->tcp_loose == 0) { | |
810 | /* Don't try to pick up connections. */ | |
811 | return false; | |
812 | } else { | |
813 | memset(&ct->proto.tcp, 0, sizeof(ct->proto.tcp)); | |
814 | /* | |
815 | * We are in the middle of a connection, | |
816 | * its history is lost for us. | |
817 | * Let's try to use the data from the packet. | |
818 | */ | |
819 | ct->proto.tcp.seen[0].td_end = | |
820 | segment_seq_plus_len(ntohl(th->seq), skb->len, | |
821 | dataoff, th); | |
822 | ct->proto.tcp.seen[0].td_maxwin = ntohs(th->window); | |
823 | if (ct->proto.tcp.seen[0].td_maxwin == 0) | |
824 | ct->proto.tcp.seen[0].td_maxwin = 1; | |
825 | ct->proto.tcp.seen[0].td_maxend = | |
826 | ct->proto.tcp.seen[0].td_end + | |
827 | ct->proto.tcp.seen[0].td_maxwin; | |
828 | ||
829 | /* We assume SACK and liberal window checking to handle | |
830 | * window scaling */ | |
831 | ct->proto.tcp.seen[0].flags = | |
832 | ct->proto.tcp.seen[1].flags = IP_CT_TCP_FLAG_SACK_PERM | | |
833 | IP_CT_TCP_FLAG_BE_LIBERAL; | |
834 | } | |
835 | ||
836 | /* tcp_packet will set them */ | |
837 | ct->proto.tcp.last_index = TCP_NONE_SET; | |
838 | ||
839 | pr_debug("%s: sender end=%u maxend=%u maxwin=%u scale=%i " | |
840 | "receiver end=%u maxend=%u maxwin=%u scale=%i\n", | |
841 | __func__, | |
842 | sender->td_end, sender->td_maxend, sender->td_maxwin, | |
843 | sender->td_scale, | |
844 | receiver->td_end, receiver->td_maxend, receiver->td_maxwin, | |
845 | receiver->td_scale); | |
846 | return true; | |
9fb9cbb1 YK |
847 | } |
848 | ||
c4edc3cc AA |
849 | static bool tcp_can_early_drop(const struct nf_conn *ct) |
850 | { | |
851 | switch (ct->proto.tcp.state) { | |
852 | case TCP_CONNTRACK_FIN_WAIT: | |
853 | case TCP_CONNTRACK_LAST_ACK: | |
854 | case TCP_CONNTRACK_TIME_WAIT: | |
855 | case TCP_CONNTRACK_CLOSE: | |
856 | case TCP_CONNTRACK_CLOSE_WAIT: | |
857 | return true; | |
858 | default: | |
859 | break; | |
860 | } | |
861 | ||
862 | return false; | |
863 | } | |
864 | ||
9fb9cbb1 | 865 | /* Returns verdict for packet, or -1 for invalid. */ |
a47c5404 FW |
866 | int nf_conntrack_tcp_packet(struct nf_conn *ct, |
867 | struct sk_buff *skb, | |
868 | unsigned int dataoff, | |
869 | enum ip_conntrack_info ctinfo, | |
870 | const struct nf_hook_state *state) | |
9fb9cbb1 | 871 | { |
c2a2c7e0 | 872 | struct net *net = nf_ct_net(ct); |
a95a7774 | 873 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
0d53778e | 874 | struct nf_conntrack_tuple *tuple; |
9fb9cbb1 | 875 | enum tcp_conntrack new_state, old_state; |
c779e849 | 876 | unsigned int index, *timeouts; |
9fb9cbb1 | 877 | enum ip_conntrack_dir dir; |
82f568fc JE |
878 | const struct tcphdr *th; |
879 | struct tcphdr _tcph; | |
9fb9cbb1 | 880 | unsigned long timeout; |
9fb9cbb1 YK |
881 | |
882 | th = skb_header_pointer(skb, dataoff, sizeof(_tcph), &_tcph); | |
9976fc6e FW |
883 | if (th == NULL) |
884 | return -NF_ACCEPT; | |
885 | ||
0150ffba FW |
886 | if (tcp_error(th, skb, dataoff, state)) |
887 | return -NF_ACCEPT; | |
888 | ||
9976fc6e FW |
889 | if (!nf_ct_is_confirmed(ct) && !tcp_new(ct, skb, dataoff, th)) |
890 | return -NF_ACCEPT; | |
9fb9cbb1 | 891 | |
440f0d58 | 892 | spin_lock_bh(&ct->lock); |
c88130bc | 893 | old_state = ct->proto.tcp.state; |
9fb9cbb1 YK |
894 | dir = CTINFO2DIR(ctinfo); |
895 | index = get_conntrack_index(th); | |
896 | new_state = tcp_conntracks[dir][index][old_state]; | |
c88130bc | 897 | tuple = &ct->tuplehash[dir].tuple; |
9fb9cbb1 YK |
898 | |
899 | switch (new_state) { | |
17311393 JK |
900 | case TCP_CONNTRACK_SYN_SENT: |
901 | if (old_state < TCP_CONNTRACK_TIME_WAIT) | |
902 | break; | |
b2155e7f JK |
903 | /* RFC 1122: "When a connection is closed actively, |
904 | * it MUST linger in TIME-WAIT state for a time 2xMSL | |
905 | * (Maximum Segment Lifetime). However, it MAY accept | |
906 | * a new SYN from the remote TCP to reopen the connection | |
907 | * directly from TIME-WAIT state, if..." | |
908 | * We ignore the conditions because we are in the | |
909 | * TIME-WAIT state anyway. | |
910 | * | |
911 | * Handle aborted connections: we and the server | |
912 | * think there is an existing connection but the client | |
913 | * aborts it and starts a new one. | |
914 | */ | |
915 | if (((ct->proto.tcp.seen[dir].flags | |
916 | | ct->proto.tcp.seen[!dir].flags) | |
917 | & IP_CT_TCP_FLAG_CLOSE_INIT) | |
c88130bc PM |
918 | || (ct->proto.tcp.last_dir == dir |
919 | && ct->proto.tcp.last_index == TCP_RST_SET)) { | |
bc34b841 JK |
920 | /* Attempt to reopen a closed/aborted connection. |
921 | * Delete this connection and look up again. */ | |
440f0d58 | 922 | spin_unlock_bh(&ct->lock); |
2aec609f | 923 | |
6b69fe0c PM |
924 | /* Only repeat if we can actually remove the timer. |
925 | * Destruction may already be in progress in process | |
926 | * context and we must give it a chance to terminate. | |
927 | */ | |
2aec609f | 928 | if (nf_ct_kill(ct)) |
6b69fe0c | 929 | return -NF_REPEAT; |
ec8d5409 | 930 | return NF_DROP; |
17311393 | 931 | } |
954d8297 | 932 | fallthrough; |
9fb9cbb1 | 933 | case TCP_CONNTRACK_IGNORE: |
73f30602 | 934 | /* Ignored packets: |
b2155e7f JK |
935 | * |
936 | * Our connection entry may be out of sync, so ignore | |
937 | * packets which may signal the real connection between | |
938 | * the client and the server. | |
73f30602 JK |
939 | * |
940 | * a) SYN in ORIGINAL | |
941 | * b) SYN/ACK in REPLY | |
601e68e1 | 942 | * c) ACK in reply direction after initial SYN in original. |
b2155e7f JK |
943 | * |
944 | * If the ignored packet is invalid, the receiver will send | |
945 | * a RST we'll catch below. | |
73f30602 | 946 | */ |
9fb9cbb1 | 947 | if (index == TCP_SYNACK_SET |
c88130bc PM |
948 | && ct->proto.tcp.last_index == TCP_SYN_SET |
949 | && ct->proto.tcp.last_dir != dir | |
950 | && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { | |
b2155e7f | 951 | /* b) This SYN/ACK acknowledges a SYN that we earlier |
9fb9cbb1 YK |
952 | * ignored as invalid. This means that the client and |
953 | * the server are both in sync, while the firewall is | |
c4832c7b PNA |
954 | * not. We get in sync from the previously annotated |
955 | * values. | |
9fb9cbb1 | 956 | */ |
c4832c7b PNA |
957 | old_state = TCP_CONNTRACK_SYN_SENT; |
958 | new_state = TCP_CONNTRACK_SYN_RECV; | |
959 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_end = | |
960 | ct->proto.tcp.last_end; | |
961 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxend = | |
962 | ct->proto.tcp.last_end; | |
963 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_maxwin = | |
964 | ct->proto.tcp.last_win == 0 ? | |
965 | 1 : ct->proto.tcp.last_win; | |
966 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].td_scale = | |
967 | ct->proto.tcp.last_wscale; | |
b3cad287 | 968 | ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; |
c4832c7b PNA |
969 | ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags = |
970 | ct->proto.tcp.last_flags; | |
971 | memset(&ct->proto.tcp.seen[dir], 0, | |
972 | sizeof(struct ip_ct_tcp_state)); | |
973 | break; | |
9fb9cbb1 | 974 | } |
c88130bc PM |
975 | ct->proto.tcp.last_index = index; |
976 | ct->proto.tcp.last_dir = dir; | |
977 | ct->proto.tcp.last_seq = ntohl(th->seq); | |
978 | ct->proto.tcp.last_end = | |
9fb9cbb1 | 979 | segment_seq_plus_len(ntohl(th->seq), skb->len, dataoff, th); |
c4832c7b PNA |
980 | ct->proto.tcp.last_win = ntohs(th->window); |
981 | ||
982 | /* a) This is a SYN in ORIGINAL. The client and the server | |
983 | * may be in sync but we are not. In that case, we annotate | |
984 | * the TCP options and let the packet go through. If it is a | |
985 | * valid SYN packet, the server will reply with a SYN/ACK, and | |
b3cad287 JDB |
986 | * then we'll get in sync. Otherwise, the server potentially |
987 | * responds with a challenge ACK if implementing RFC5961. | |
988 | */ | |
c4832c7b PNA |
989 | if (index == TCP_SYN_SET && dir == IP_CT_DIR_ORIGINAL) { |
990 | struct ip_ct_tcp_state seen = {}; | |
991 | ||
992 | ct->proto.tcp.last_flags = | |
993 | ct->proto.tcp.last_wscale = 0; | |
994 | tcp_options(skb, dataoff, th, &seen); | |
995 | if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { | |
996 | ct->proto.tcp.last_flags |= | |
997 | IP_CT_TCP_FLAG_WINDOW_SCALE; | |
998 | ct->proto.tcp.last_wscale = seen.td_scale; | |
999 | } | |
1000 | if (seen.flags & IP_CT_TCP_FLAG_SACK_PERM) { | |
1001 | ct->proto.tcp.last_flags |= | |
1002 | IP_CT_TCP_FLAG_SACK_PERM; | |
1003 | } | |
b3cad287 JDB |
1004 | /* Mark the potential for RFC5961 challenge ACK, |
1005 | * this pose a special problem for LAST_ACK state | |
1006 | * as ACK is intrepretated as ACKing last FIN. | |
1007 | */ | |
1008 | if (old_state == TCP_CONNTRACK_LAST_ACK) | |
1009 | ct->proto.tcp.last_flags |= | |
1010 | IP_CT_EXP_CHALLENGE_ACK; | |
c4832c7b | 1011 | } |
440f0d58 | 1012 | spin_unlock_bh(&ct->lock); |
62eec0d7 | 1013 | nf_ct_l4proto_log_invalid(skb, ct, state, |
07b5a76e FW |
1014 | "packet (index %d) in dir %d ignored, state %s", |
1015 | index, dir, | |
1016 | tcp_conntrack_names[old_state]); | |
9fb9cbb1 YK |
1017 | return NF_ACCEPT; |
1018 | case TCP_CONNTRACK_MAX: | |
48b1de4c PM |
1019 | /* Special case for SYN proxy: when the SYN to the server or |
1020 | * the SYN/ACK from the server is lost, the client may transmit | |
1021 | * a keep-alive packet while in SYN_SENT state. This needs to | |
1022 | * be associated with the original conntrack entry in order to | |
1023 | * generate a new SYN with the correct sequence number. | |
1024 | */ | |
1025 | if (nfct_synproxy(ct) && old_state == TCP_CONNTRACK_SYN_SENT && | |
1026 | index == TCP_ACK_SET && dir == IP_CT_DIR_ORIGINAL && | |
1027 | ct->proto.tcp.last_dir == IP_CT_DIR_ORIGINAL && | |
1028 | ct->proto.tcp.seen[dir].td_end - 1 == ntohl(th->seq)) { | |
1029 | pr_debug("nf_ct_tcp: SYN proxy client keep alive\n"); | |
1030 | spin_unlock_bh(&ct->lock); | |
1031 | return NF_ACCEPT; | |
1032 | } | |
1033 | ||
9fb9cbb1 | 1034 | /* Invalid packet */ |
0d53778e PM |
1035 | pr_debug("nf_ct_tcp: Invalid dir=%i index=%u ostate=%u\n", |
1036 | dir, get_conntrack_index(th), old_state); | |
440f0d58 | 1037 | spin_unlock_bh(&ct->lock); |
62eec0d7 | 1038 | nf_ct_l4proto_log_invalid(skb, ct, state, "invalid state"); |
9fb9cbb1 | 1039 | return -NF_ACCEPT; |
b3cad287 JDB |
1040 | case TCP_CONNTRACK_TIME_WAIT: |
1041 | /* RFC5961 compliance cause stack to send "challenge-ACK" | |
1042 | * e.g. in response to spurious SYNs. Conntrack MUST | |
1043 | * not believe this ACK is acking last FIN. | |
1044 | */ | |
1045 | if (old_state == TCP_CONNTRACK_LAST_ACK && | |
1046 | index == TCP_ACK_SET && | |
1047 | ct->proto.tcp.last_dir != dir && | |
1048 | ct->proto.tcp.last_index == TCP_SYN_SET && | |
1049 | (ct->proto.tcp.last_flags & IP_CT_EXP_CHALLENGE_ACK)) { | |
1050 | /* Detected RFC5961 challenge ACK */ | |
1051 | ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK; | |
1052 | spin_unlock_bh(&ct->lock); | |
62eec0d7 | 1053 | nf_ct_l4proto_log_invalid(skb, ct, state, "challenge-ack ignored"); |
b3cad287 JDB |
1054 | return NF_ACCEPT; /* Don't change state */ |
1055 | } | |
1056 | break; | |
72d4d3e3 JK |
1057 | case TCP_CONNTRACK_SYN_SENT2: |
1058 | /* tcp_conntracks table is not smart enough to handle | |
1059 | * simultaneous open. | |
1060 | */ | |
1061 | ct->proto.tcp.last_flags |= IP_CT_TCP_SIMULTANEOUS_OPEN; | |
1062 | break; | |
1063 | case TCP_CONNTRACK_SYN_RECV: | |
1064 | if (dir == IP_CT_DIR_REPLY && index == TCP_ACK_SET && | |
1065 | ct->proto.tcp.last_flags & IP_CT_TCP_SIMULTANEOUS_OPEN) | |
1066 | new_state = TCP_CONNTRACK_ESTABLISHED; | |
1067 | break; | |
9fb9cbb1 | 1068 | case TCP_CONNTRACK_CLOSE: |
be0502a3 FW |
1069 | if (index != TCP_RST_SET) |
1070 | break; | |
1071 | ||
c4edc3cc AA |
1072 | /* If we are closing, tuple might have been re-used already. |
1073 | * last_index, last_ack, and all other ct fields used for | |
1074 | * sequence/window validation are outdated in that case. | |
1075 | * | |
1076 | * As the conntrack can already be expired by GC under pressure, | |
1077 | * just skip validation checks. | |
1078 | */ | |
1079 | if (tcp_can_early_drop(ct)) | |
1080 | goto in_window; | |
1081 | ||
1082 | /* td_maxack might be outdated if we let a SYN through earlier */ | |
1083 | if ((ct->proto.tcp.seen[!dir].flags & IP_CT_TCP_FLAG_MAXACK_SET) && | |
1084 | ct->proto.tcp.last_index != TCP_SYN_SET) { | |
be0502a3 FW |
1085 | u32 seq = ntohl(th->seq); |
1086 | ||
c4edc3cc AA |
1087 | /* If we are not in established state and SEQ=0 this is most |
1088 | * likely an answer to a SYN we let go through above (last_index | |
1089 | * can be updated due to out-of-order ACKs). | |
1090 | */ | |
1091 | if (seq == 0 && !nf_conntrack_tcp_established(ct)) | |
1092 | break; | |
1093 | ||
1da4cd82 AA |
1094 | if (before(seq, ct->proto.tcp.seen[!dir].td_maxack) && |
1095 | !tn->tcp_ignore_invalid_rst) { | |
be0502a3 FW |
1096 | /* Invalid RST */ |
1097 | spin_unlock_bh(&ct->lock); | |
62eec0d7 | 1098 | nf_ct_l4proto_log_invalid(skb, ct, state, "invalid rst"); |
be0502a3 FW |
1099 | return -NF_ACCEPT; |
1100 | } | |
1101 | ||
1102 | if (!nf_conntrack_tcp_established(ct) || | |
1103 | seq == ct->proto.tcp.seen[!dir].td_maxack) | |
1104 | break; | |
1105 | ||
1106 | /* Check if rst is part of train, such as | |
1107 | * foo:80 > bar:4379: P, 235946583:235946602(19) ack 42 | |
1108 | * foo:80 > bar:4379: R, 235946602:235946602(0) ack 42 | |
1109 | */ | |
1110 | if (ct->proto.tcp.last_index == TCP_ACK_SET && | |
1111 | ct->proto.tcp.last_dir == dir && | |
1112 | seq == ct->proto.tcp.last_end) | |
1113 | break; | |
1114 | ||
1115 | /* ... RST sequence number doesn't match exactly, keep | |
1116 | * established state to allow a possible challenge ACK. | |
1117 | */ | |
1118 | new_state = old_state; | |
bfcaa502 | 1119 | } |
be0502a3 | 1120 | if (((test_bit(IPS_SEEN_REPLY_BIT, &ct->status) |
c88130bc PM |
1121 | && ct->proto.tcp.last_index == TCP_SYN_SET) |
1122 | || (!test_bit(IPS_ASSURED_BIT, &ct->status) | |
1123 | && ct->proto.tcp.last_index == TCP_ACK_SET)) | |
1124 | && ntohl(th->ack_seq) == ct->proto.tcp.last_end) { | |
93b1fae4 | 1125 | /* RST sent to invalid SYN or ACK we had let through |
73f30602 JK |
1126 | * at a) and c) above: |
1127 | * | |
1128 | * a) SYN was in window then | |
1129 | * c) we hold a half-open connection. | |
1130 | * | |
1131 | * Delete our connection entry. | |
9fb9cbb1 | 1132 | * We skip window checking, because packet might ACK |
73f30602 | 1133 | * segments we ignored. */ |
9fb9cbb1 YK |
1134 | goto in_window; |
1135 | } | |
be0502a3 | 1136 | break; |
9fb9cbb1 YK |
1137 | default: |
1138 | /* Keep compilers happy. */ | |
1139 | break; | |
1140 | } | |
1141 | ||
62eec0d7 FW |
1142 | if (!tcp_in_window(ct, dir, index, |
1143 | skb, dataoff, th, state)) { | |
440f0d58 | 1144 | spin_unlock_bh(&ct->lock); |
9fb9cbb1 YK |
1145 | return -NF_ACCEPT; |
1146 | } | |
1147 | in_window: | |
1148 | /* From now on we have got in-window packets */ | |
c88130bc PM |
1149 | ct->proto.tcp.last_index = index; |
1150 | ct->proto.tcp.last_dir = dir; | |
9fb9cbb1 | 1151 | |
0d53778e | 1152 | pr_debug("tcp_conntracks: "); |
3c9fba65 | 1153 | nf_ct_dump_tuple(tuple); |
0d53778e PM |
1154 | pr_debug("syn=%i ack=%i fin=%i rst=%i old=%i new=%i\n", |
1155 | (th->syn ? 1 : 0), (th->ack ? 1 : 0), | |
1156 | (th->fin ? 1 : 0), (th->rst ? 1 : 0), | |
1157 | old_state, new_state); | |
9fb9cbb1 | 1158 | |
c88130bc | 1159 | ct->proto.tcp.state = new_state; |
9fb9cbb1 | 1160 | if (old_state != new_state |
d0c1fd7a | 1161 | && new_state == TCP_CONNTRACK_FIN_WAIT) |
c88130bc | 1162 | ct->proto.tcp.seen[dir].flags |= IP_CT_TCP_FLAG_CLOSE_INIT; |
ae375044 | 1163 | |
c779e849 FW |
1164 | timeouts = nf_ct_timeout_lookup(ct); |
1165 | if (!timeouts) | |
1166 | timeouts = tn->timeouts; | |
1167 | ||
d2ba1fde | 1168 | if (ct->proto.tcp.retrans >= tn->tcp_max_retrans && |
2c8503f5 PNA |
1169 | timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) |
1170 | timeout = timeouts[TCP_CONNTRACK_RETRANS]; | |
be0502a3 FW |
1171 | else if (unlikely(index == TCP_RST_SET)) |
1172 | timeout = timeouts[TCP_CONNTRACK_CLOSE]; | |
ae375044 PM |
1173 | else if ((ct->proto.tcp.seen[0].flags | ct->proto.tcp.seen[1].flags) & |
1174 | IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED && | |
2c8503f5 PNA |
1175 | timeouts[new_state] > timeouts[TCP_CONNTRACK_UNACK]) |
1176 | timeout = timeouts[TCP_CONNTRACK_UNACK]; | |
fbcd253d FW |
1177 | else if (ct->proto.tcp.last_win == 0 && |
1178 | timeouts[new_state] > timeouts[TCP_CONNTRACK_RETRANS]) | |
1179 | timeout = timeouts[TCP_CONNTRACK_RETRANS]; | |
ae375044 | 1180 | else |
2c8503f5 | 1181 | timeout = timeouts[new_state]; |
440f0d58 | 1182 | spin_unlock_bh(&ct->lock); |
9fb9cbb1 | 1183 | |
9fb9cbb1 | 1184 | if (new_state != old_state) |
a71996fc | 1185 | nf_conntrack_event_cache(IPCT_PROTOINFO, ct); |
9fb9cbb1 | 1186 | |
c88130bc | 1187 | if (!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { |
9fb9cbb1 YK |
1188 | /* If only reply is a RST, we can consider ourselves not to |
1189 | have an established connection: this is a fairly common | |
1190 | problem case, so we can delete the conntrack | |
1191 | immediately. --RR */ | |
1192 | if (th->rst) { | |
718d4ad9 | 1193 | nf_ct_kill_acct(ct, ctinfo, skb); |
9fb9cbb1 YK |
1194 | return NF_ACCEPT; |
1195 | } | |
e15d4cdf FW |
1196 | |
1197 | if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) { | |
1198 | /* do not renew timeout on SYN retransmit. | |
1199 | * | |
1200 | * Else port reuse by client or NAT middlebox can keep | |
1201 | * entry alive indefinitely (including nat info). | |
1202 | */ | |
1203 | return NF_ACCEPT; | |
1204 | } | |
1205 | ||
6547a221 FW |
1206 | /* ESTABLISHED without SEEN_REPLY, i.e. mid-connection |
1207 | * pickup with loose=1. Avoid large ESTABLISHED timeout. | |
1208 | */ | |
1209 | if (new_state == TCP_CONNTRACK_ESTABLISHED && | |
1210 | timeout > timeouts[TCP_CONNTRACK_UNACK]) | |
1211 | timeout = timeouts[TCP_CONNTRACK_UNACK]; | |
c88130bc | 1212 | } else if (!test_bit(IPS_ASSURED_BIT, &ct->status) |
9fb9cbb1 YK |
1213 | && (old_state == TCP_CONNTRACK_SYN_RECV |
1214 | || old_state == TCP_CONNTRACK_ESTABLISHED) | |
1215 | && new_state == TCP_CONNTRACK_ESTABLISHED) { | |
4b7ddc58 | 1216 | /* Set ASSURED if we see valid ack in ESTABLISHED |
601e68e1 | 1217 | after SYN_RECV or a valid answer for a picked up |
9fb9cbb1 | 1218 | connection. */ |
c88130bc | 1219 | set_bit(IPS_ASSURED_BIT, &ct->status); |
858b3133 | 1220 | nf_conntrack_event_cache(IPCT_ASSURED, ct); |
9fb9cbb1 | 1221 | } |
c88130bc | 1222 | nf_ct_refresh_acct(ct, ctinfo, skb, timeout); |
9fb9cbb1 YK |
1223 | |
1224 | return NF_ACCEPT; | |
1225 | } | |
601e68e1 | 1226 | |
c0cd1156 | 1227 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
c1d10adb PNA |
1228 | |
1229 | #include <linux/netfilter/nfnetlink.h> | |
1230 | #include <linux/netfilter/nfnetlink_conntrack.h> | |
1231 | ||
fdf70832 | 1232 | static int tcp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, |
86d21fc7 | 1233 | struct nf_conn *ct, bool destroy) |
c1d10adb | 1234 | { |
df6fb868 | 1235 | struct nlattr *nest_parms; |
c8e2078c | 1236 | struct nf_ct_tcp_flags tmp = {}; |
601e68e1 | 1237 | |
440f0d58 | 1238 | spin_lock_bh(&ct->lock); |
ae0be8de | 1239 | nest_parms = nla_nest_start(skb, CTA_PROTOINFO_TCP); |
df6fb868 PM |
1240 | if (!nest_parms) |
1241 | goto nla_put_failure; | |
1242 | ||
86d21fc7 FW |
1243 | if (nla_put_u8(skb, CTA_PROTOINFO_TCP_STATE, ct->proto.tcp.state)) |
1244 | goto nla_put_failure; | |
1245 | ||
1246 | if (destroy) | |
1247 | goto skip_state; | |
1248 | ||
1249 | if (nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_ORIGINAL, | |
4925a459 DM |
1250 | ct->proto.tcp.seen[0].td_scale) || |
1251 | nla_put_u8(skb, CTA_PROTOINFO_TCP_WSCALE_REPLY, | |
1252 | ct->proto.tcp.seen[1].td_scale)) | |
1253 | goto nla_put_failure; | |
c8e2078c PNA |
1254 | |
1255 | tmp.flags = ct->proto.tcp.seen[0].flags; | |
4925a459 DM |
1256 | if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_ORIGINAL, |
1257 | sizeof(struct nf_ct_tcp_flags), &tmp)) | |
1258 | goto nla_put_failure; | |
c8e2078c PNA |
1259 | |
1260 | tmp.flags = ct->proto.tcp.seen[1].flags; | |
4925a459 DM |
1261 | if (nla_put(skb, CTA_PROTOINFO_TCP_FLAGS_REPLY, |
1262 | sizeof(struct nf_ct_tcp_flags), &tmp)) | |
1263 | goto nla_put_failure; | |
86d21fc7 | 1264 | skip_state: |
440f0d58 | 1265 | spin_unlock_bh(&ct->lock); |
df6fb868 | 1266 | nla_nest_end(skb, nest_parms); |
c1d10adb PNA |
1267 | |
1268 | return 0; | |
1269 | ||
df6fb868 | 1270 | nla_put_failure: |
440f0d58 | 1271 | spin_unlock_bh(&ct->lock); |
c1d10adb PNA |
1272 | return -1; |
1273 | } | |
1274 | ||
f73e924c PM |
1275 | static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = { |
1276 | [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 }, | |
1277 | [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 }, | |
1278 | [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 }, | |
1279 | [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) }, | |
7e59b3fe | 1280 | [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) }, |
c1d10adb PNA |
1281 | }; |
1282 | ||
39215846 FW |
1283 | #define TCP_NLATTR_SIZE ( \ |
1284 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
1285 | NLA_ALIGN(NLA_HDRLEN + 1) + \ | |
346fa83d | 1286 | NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags)) + \ |
1287 | NLA_ALIGN(NLA_HDRLEN + sizeof(struct nf_ct_tcp_flags))) | |
39215846 | 1288 | |
fdf70832 | 1289 | static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct) |
c1d10adb | 1290 | { |
2f0d2f10 | 1291 | struct nlattr *pattr = cda[CTA_PROTOINFO_TCP]; |
df6fb868 | 1292 | struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1]; |
f73e924c | 1293 | int err; |
c1d10adb PNA |
1294 | |
1295 | /* updates could not contain anything about the private | |
1296 | * protocol info, in that case skip the parsing */ | |
2f0d2f10 | 1297 | if (!pattr) |
c1d10adb PNA |
1298 | return 0; |
1299 | ||
8cb08174 JB |
1300 | err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_TCP_MAX, pattr, |
1301 | tcp_nla_policy, NULL); | |
f73e924c PM |
1302 | if (err < 0) |
1303 | return err; | |
c1d10adb | 1304 | |
5f7da4d2 PM |
1305 | if (tb[CTA_PROTOINFO_TCP_STATE] && |
1306 | nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX) | |
c1d10adb PNA |
1307 | return -EINVAL; |
1308 | ||
440f0d58 | 1309 | spin_lock_bh(&ct->lock); |
5f7da4d2 PM |
1310 | if (tb[CTA_PROTOINFO_TCP_STATE]) |
1311 | ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]); | |
c8e2078c | 1312 | |
df6fb868 | 1313 | if (tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]) { |
c8e2078c | 1314 | struct nf_ct_tcp_flags *attr = |
df6fb868 | 1315 | nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL]); |
c8e2078c PNA |
1316 | ct->proto.tcp.seen[0].flags &= ~attr->mask; |
1317 | ct->proto.tcp.seen[0].flags |= attr->flags & attr->mask; | |
1318 | } | |
1319 | ||
df6fb868 | 1320 | if (tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]) { |
c8e2078c | 1321 | struct nf_ct_tcp_flags *attr = |
df6fb868 | 1322 | nla_data(tb[CTA_PROTOINFO_TCP_FLAGS_REPLY]); |
c8e2078c PNA |
1323 | ct->proto.tcp.seen[1].flags &= ~attr->mask; |
1324 | ct->proto.tcp.seen[1].flags |= attr->flags & attr->mask; | |
1325 | } | |
1326 | ||
df6fb868 PM |
1327 | if (tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] && |
1328 | tb[CTA_PROTOINFO_TCP_WSCALE_REPLY] && | |
c8e2078c PNA |
1329 | ct->proto.tcp.seen[0].flags & IP_CT_TCP_FLAG_WINDOW_SCALE && |
1330 | ct->proto.tcp.seen[1].flags & IP_CT_TCP_FLAG_WINDOW_SCALE) { | |
77236b6e PM |
1331 | ct->proto.tcp.seen[0].td_scale = |
1332 | nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL]); | |
1333 | ct->proto.tcp.seen[1].td_scale = | |
1334 | nla_get_u8(tb[CTA_PROTOINFO_TCP_WSCALE_REPLY]); | |
c8e2078c | 1335 | } |
440f0d58 | 1336 | spin_unlock_bh(&ct->lock); |
c1d10adb PNA |
1337 | |
1338 | return 0; | |
1339 | } | |
a400c30e | 1340 | |
5caaed15 | 1341 | static unsigned int tcp_nlattr_tuple_size(void) |
a400c30e | 1342 | { |
5caaed15 FW |
1343 | static unsigned int size __read_mostly; |
1344 | ||
1345 | if (!size) | |
1346 | size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); | |
1347 | ||
1348 | return size; | |
a400c30e | 1349 | } |
c1d10adb | 1350 | #endif |
933a41e7 | 1351 | |
a874752a | 1352 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
1353 | |
1354 | #include <linux/netfilter/nfnetlink.h> | |
1355 | #include <linux/netfilter/nfnetlink_cttimeout.h> | |
1356 | ||
8264deb8 G |
1357 | static int tcp_timeout_nlattr_to_obj(struct nlattr *tb[], |
1358 | struct net *net, void *data) | |
50978462 | 1359 | { |
a95a7774 | 1360 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
c779e849 | 1361 | unsigned int *timeouts = data; |
50978462 PNA |
1362 | int i; |
1363 | ||
c779e849 FW |
1364 | if (!timeouts) |
1365 | timeouts = tn->timeouts; | |
50978462 PNA |
1366 | /* set default TCP timeouts. */ |
1367 | for (i=0; i<TCP_CONNTRACK_TIMEOUT_MAX; i++) | |
8264deb8 | 1368 | timeouts[i] = tn->timeouts[i]; |
50978462 PNA |
1369 | |
1370 | if (tb[CTA_TIMEOUT_TCP_SYN_SENT]) { | |
1371 | timeouts[TCP_CONNTRACK_SYN_SENT] = | |
1372 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT]))*HZ; | |
1373 | } | |
ef39078d | 1374 | |
50978462 PNA |
1375 | if (tb[CTA_TIMEOUT_TCP_SYN_RECV]) { |
1376 | timeouts[TCP_CONNTRACK_SYN_RECV] = | |
1377 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_RECV]))*HZ; | |
1378 | } | |
1379 | if (tb[CTA_TIMEOUT_TCP_ESTABLISHED]) { | |
1380 | timeouts[TCP_CONNTRACK_ESTABLISHED] = | |
1381 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_ESTABLISHED]))*HZ; | |
1382 | } | |
1383 | if (tb[CTA_TIMEOUT_TCP_FIN_WAIT]) { | |
1384 | timeouts[TCP_CONNTRACK_FIN_WAIT] = | |
1385 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_FIN_WAIT]))*HZ; | |
1386 | } | |
1387 | if (tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]) { | |
1388 | timeouts[TCP_CONNTRACK_CLOSE_WAIT] = | |
1389 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE_WAIT]))*HZ; | |
1390 | } | |
1391 | if (tb[CTA_TIMEOUT_TCP_LAST_ACK]) { | |
1392 | timeouts[TCP_CONNTRACK_LAST_ACK] = | |
1393 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_LAST_ACK]))*HZ; | |
1394 | } | |
1395 | if (tb[CTA_TIMEOUT_TCP_TIME_WAIT]) { | |
1396 | timeouts[TCP_CONNTRACK_TIME_WAIT] = | |
1397 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_TIME_WAIT]))*HZ; | |
1398 | } | |
1399 | if (tb[CTA_TIMEOUT_TCP_CLOSE]) { | |
1400 | timeouts[TCP_CONNTRACK_CLOSE] = | |
1401 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_CLOSE]))*HZ; | |
1402 | } | |
1403 | if (tb[CTA_TIMEOUT_TCP_SYN_SENT2]) { | |
1404 | timeouts[TCP_CONNTRACK_SYN_SENT2] = | |
1405 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_SYN_SENT2]))*HZ; | |
1406 | } | |
1407 | if (tb[CTA_TIMEOUT_TCP_RETRANS]) { | |
1408 | timeouts[TCP_CONNTRACK_RETRANS] = | |
1409 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_RETRANS]))*HZ; | |
1410 | } | |
1411 | if (tb[CTA_TIMEOUT_TCP_UNACK]) { | |
1412 | timeouts[TCP_CONNTRACK_UNACK] = | |
1413 | ntohl(nla_get_be32(tb[CTA_TIMEOUT_TCP_UNACK]))*HZ; | |
1414 | } | |
ef39078d FW |
1415 | |
1416 | timeouts[CTA_TIMEOUT_TCP_UNSPEC] = timeouts[CTA_TIMEOUT_TCP_SYN_SENT]; | |
50978462 PNA |
1417 | return 0; |
1418 | } | |
1419 | ||
1420 | static int | |
1421 | tcp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data) | |
1422 | { | |
1423 | const unsigned int *timeouts = data; | |
1424 | ||
4925a459 DM |
1425 | if (nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT, |
1426 | htonl(timeouts[TCP_CONNTRACK_SYN_SENT] / HZ)) || | |
1427 | nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_RECV, | |
1428 | htonl(timeouts[TCP_CONNTRACK_SYN_RECV] / HZ)) || | |
1429 | nla_put_be32(skb, CTA_TIMEOUT_TCP_ESTABLISHED, | |
1430 | htonl(timeouts[TCP_CONNTRACK_ESTABLISHED] / HZ)) || | |
1431 | nla_put_be32(skb, CTA_TIMEOUT_TCP_FIN_WAIT, | |
1432 | htonl(timeouts[TCP_CONNTRACK_FIN_WAIT] / HZ)) || | |
1433 | nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE_WAIT, | |
1434 | htonl(timeouts[TCP_CONNTRACK_CLOSE_WAIT] / HZ)) || | |
1435 | nla_put_be32(skb, CTA_TIMEOUT_TCP_LAST_ACK, | |
1436 | htonl(timeouts[TCP_CONNTRACK_LAST_ACK] / HZ)) || | |
1437 | nla_put_be32(skb, CTA_TIMEOUT_TCP_TIME_WAIT, | |
1438 | htonl(timeouts[TCP_CONNTRACK_TIME_WAIT] / HZ)) || | |
1439 | nla_put_be32(skb, CTA_TIMEOUT_TCP_CLOSE, | |
1440 | htonl(timeouts[TCP_CONNTRACK_CLOSE] / HZ)) || | |
1441 | nla_put_be32(skb, CTA_TIMEOUT_TCP_SYN_SENT2, | |
1442 | htonl(timeouts[TCP_CONNTRACK_SYN_SENT2] / HZ)) || | |
1443 | nla_put_be32(skb, CTA_TIMEOUT_TCP_RETRANS, | |
1444 | htonl(timeouts[TCP_CONNTRACK_RETRANS] / HZ)) || | |
1445 | nla_put_be32(skb, CTA_TIMEOUT_TCP_UNACK, | |
1446 | htonl(timeouts[TCP_CONNTRACK_UNACK] / HZ))) | |
1447 | goto nla_put_failure; | |
50978462 PNA |
1448 | return 0; |
1449 | ||
1450 | nla_put_failure: | |
1451 | return -ENOSPC; | |
1452 | } | |
1453 | ||
1454 | static const struct nla_policy tcp_timeout_nla_policy[CTA_TIMEOUT_TCP_MAX+1] = { | |
1455 | [CTA_TIMEOUT_TCP_SYN_SENT] = { .type = NLA_U32 }, | |
1456 | [CTA_TIMEOUT_TCP_SYN_RECV] = { .type = NLA_U32 }, | |
1457 | [CTA_TIMEOUT_TCP_ESTABLISHED] = { .type = NLA_U32 }, | |
1458 | [CTA_TIMEOUT_TCP_FIN_WAIT] = { .type = NLA_U32 }, | |
1459 | [CTA_TIMEOUT_TCP_CLOSE_WAIT] = { .type = NLA_U32 }, | |
1460 | [CTA_TIMEOUT_TCP_LAST_ACK] = { .type = NLA_U32 }, | |
1461 | [CTA_TIMEOUT_TCP_TIME_WAIT] = { .type = NLA_U32 }, | |
1462 | [CTA_TIMEOUT_TCP_CLOSE] = { .type = NLA_U32 }, | |
1463 | [CTA_TIMEOUT_TCP_SYN_SENT2] = { .type = NLA_U32 }, | |
6d1fafca FW |
1464 | [CTA_TIMEOUT_TCP_RETRANS] = { .type = NLA_U32 }, |
1465 | [CTA_TIMEOUT_TCP_UNACK] = { .type = NLA_U32 }, | |
50978462 | 1466 | }; |
a874752a | 1467 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
50978462 | 1468 | |
2a389de8 | 1469 | void nf_conntrack_tcp_init_net(struct net *net) |
d2ba1fde | 1470 | { |
a95a7774 | 1471 | struct nf_tcp_net *tn = nf_tcp_pernet(net); |
2a389de8 | 1472 | int i; |
d2ba1fde | 1473 | |
2a389de8 FW |
1474 | for (i = 0; i < TCP_CONNTRACK_TIMEOUT_MAX; i++) |
1475 | tn->timeouts[i] = tcp_timeouts[i]; | |
d2ba1fde | 1476 | |
2a389de8 FW |
1477 | /* timeouts[0] is unused, make it same as SYN_SENT so |
1478 | * ->timeouts[0] contains 'new' timeout, like udp or icmp. | |
1479 | */ | |
1480 | tn->timeouts[0] = tcp_timeouts[TCP_CONNTRACK_SYN_SENT]; | |
9b1a4d0f FW |
1481 | |
1482 | /* If it is set to zero, we disable picking up already established | |
1483 | * connections. | |
1484 | */ | |
1485 | tn->tcp_loose = 1; | |
1486 | ||
1487 | /* "Be conservative in what you do, | |
1488 | * be liberal in what you accept from others." | |
1489 | * If it's non-zero, we mark only out of window RST segments as INVALID. | |
1490 | */ | |
1491 | tn->tcp_be_liberal = 0; | |
1492 | ||
1da4cd82 AA |
1493 | /* If it's non-zero, we turn off RST sequence number check */ |
1494 | tn->tcp_ignore_invalid_rst = 0; | |
1495 | ||
9b1a4d0f FW |
1496 | /* Max number of the retransmitted packets without receiving an (acceptable) |
1497 | * ACK from the destination. If this number is reached, a shorter timer | |
1498 | * will be started. | |
1499 | */ | |
1500 | tn->tcp_max_retrans = 3; | |
ef8ed5ea OS |
1501 | |
1502 | #if IS_ENABLED(CONFIG_NF_FLOW_TABLE) | |
1503 | tn->offload_timeout = 30 * HZ; | |
ef8ed5ea | 1504 | #endif |
08911475 PNA |
1505 | } |
1506 | ||
dd2934a9 | 1507 | const struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp = |
9fb9cbb1 | 1508 | { |
605dcad6 | 1509 | .l4proto = IPPROTO_TCP, |
ea48cc83 | 1510 | #ifdef CONFIG_NF_CONNTRACK_PROCFS |
9fb9cbb1 | 1511 | .print_conntrack = tcp_print_conntrack, |
ea48cc83 | 1512 | #endif |
c6dd940b | 1513 | .can_early_drop = tcp_can_early_drop, |
c0cd1156 | 1514 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
fdf70832 PM |
1515 | .to_nlattr = tcp_to_nlattr, |
1516 | .from_nlattr = nlattr_to_tcp, | |
1517 | .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, | |
1518 | .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, | |
a400c30e | 1519 | .nlattr_tuple_size = tcp_nlattr_tuple_size, |
39215846 | 1520 | .nlattr_size = TCP_NLATTR_SIZE, |
f73e924c | 1521 | .nla_policy = nf_ct_port_nla_policy, |
c1d10adb | 1522 | #endif |
a874752a | 1523 | #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
50978462 PNA |
1524 | .ctnl_timeout = { |
1525 | .nlattr_to_obj = tcp_timeout_nlattr_to_obj, | |
1526 | .obj_to_nlattr = tcp_timeout_obj_to_nlattr, | |
1527 | .nlattr_max = CTA_TIMEOUT_TCP_MAX, | |
1528 | .obj_size = sizeof(unsigned int) * | |
1529 | TCP_CONNTRACK_TIMEOUT_MAX, | |
1530 | .nla_policy = tcp_timeout_nla_policy, | |
1531 | }, | |
a874752a | 1532 | #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */ |
9fb9cbb1 | 1533 | }; |