1 | /* $NetBSD: tcp_input.c,v 1.349 2016/11/15 22:23:09 mrg Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. |
5 | * All rights reserved. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * 3. Neither the name of the project nor the names of its contributors |
16 | * may be used to endorse or promote products derived from this software |
17 | * without specific prior written permission. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND |
20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE |
23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
29 | * SUCH DAMAGE. |
30 | */ |
31 | |
32 | /* |
33 | * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995 |
34 | * |
35 | * NRL grants permission for redistribution and use in source and binary |
36 | * forms, with or without modification, of the software and documentation |
37 | * created at NRL provided that the following conditions are met: |
38 | * |
39 | * 1. Redistributions of source code must retain the above copyright |
40 | * notice, this list of conditions and the following disclaimer. |
41 | * 2. Redistributions in binary form must reproduce the above copyright |
42 | * notice, this list of conditions and the following disclaimer in the |
43 | * documentation and/or other materials provided with the distribution. |
44 | * 3. All advertising materials mentioning features or use of this software |
45 | * must display the following acknowledgements: |
46 | * This product includes software developed by the University of |
47 | * California, Berkeley and its contributors. |
48 | * This product includes software developed at the Information |
49 | * Technology Division, US Naval Research Laboratory. |
50 | * 4. Neither the name of the NRL nor the names of its contributors |
51 | * may be used to endorse or promote products derived from this software |
52 | * without specific prior written permission. |
53 | * |
54 | * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS |
55 | * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
56 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
57 | * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR |
58 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
59 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
60 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
61 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
62 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
63 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
64 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
65 | * |
66 | * The views and conclusions contained in the software and documentation |
67 | * are those of the authors and should not be interpreted as representing |
68 | * official policies, either expressed or implied, of the US Naval |
69 | * Research Laboratory (NRL). |
70 | */ |
71 | |
72 | /*- |
73 | * Copyright (c) 1997, 1998, 1999, 2001, 2005, 2006, |
74 | * 2011 The NetBSD Foundation, Inc. |
75 | * All rights reserved. |
76 | * |
77 | * This code is derived from software contributed to The NetBSD Foundation |
78 | * by Coyote Point Systems, Inc. |
79 | * This code is derived from software contributed to The NetBSD Foundation |
80 | * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation |
81 | * Facility, NASA Ames Research Center. |
82 | * This code is derived from software contributed to The NetBSD Foundation |
83 | * by Charles M. Hannum. |
84 | * This code is derived from software contributed to The NetBSD Foundation |
85 | * by Rui Paulo. |
86 | * |
87 | * Redistribution and use in source and binary forms, with or without |
88 | * modification, are permitted provided that the following conditions |
89 | * are met: |
90 | * 1. Redistributions of source code must retain the above copyright |
91 | * notice, this list of conditions and the following disclaimer. |
92 | * 2. Redistributions in binary form must reproduce the above copyright |
93 | * notice, this list of conditions and the following disclaimer in the |
94 | * documentation and/or other materials provided with the distribution. |
95 | * |
96 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
97 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
98 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
99 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
100 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
101 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
102 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
103 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
104 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
105 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
106 | * POSSIBILITY OF SUCH DAMAGE. |
107 | */ |
108 | |
109 | /* |
110 | * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995 |
111 | * The Regents of the University of California. All rights reserved. |
112 | * |
113 | * Redistribution and use in source and binary forms, with or without |
114 | * modification, are permitted provided that the following conditions |
115 | * are met: |
116 | * 1. Redistributions of source code must retain the above copyright |
117 | * notice, this list of conditions and the following disclaimer. |
118 | * 2. Redistributions in binary form must reproduce the above copyright |
119 | * notice, this list of conditions and the following disclaimer in the |
120 | * documentation and/or other materials provided with the distribution. |
121 | * 3. Neither the name of the University nor the names of its contributors |
122 | * may be used to endorse or promote products derived from this software |
123 | * without specific prior written permission. |
124 | * |
125 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
126 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
127 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
128 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
129 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
130 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
131 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
132 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
133 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
134 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
135 | * SUCH DAMAGE. |
136 | * |
137 | * @(#)tcp_input.c 8.12 (Berkeley) 5/24/95 |
138 | */ |
139 | |
140 | /* |
141 | * TODO list for SYN cache stuff: |
142 | * |
143 | * Find room for a "state" field, which is needed to keep a |
144 | * compressed state for TIME_WAIT TCBs. It's been noted already |
145 | * that this is fairly important for very high-volume web and |
146 | * mail servers, which use a large number of short-lived |
147 | * connections. |
148 | */ |
149 | |
150 | #include <sys/cdefs.h> |
151 | __KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.349 2016/11/15 22:23:09 mrg Exp $" ); |
152 | |
153 | #ifdef _KERNEL_OPT |
154 | #include "opt_inet.h" |
155 | #include "opt_ipsec.h" |
156 | #include "opt_inet_csum.h" |
157 | #include "opt_tcp_debug.h" |
158 | #endif |
159 | |
160 | #include <sys/param.h> |
161 | #include <sys/systm.h> |
162 | #include <sys/malloc.h> |
163 | #include <sys/mbuf.h> |
164 | #include <sys/protosw.h> |
165 | #include <sys/socket.h> |
166 | #include <sys/socketvar.h> |
167 | #include <sys/errno.h> |
168 | #include <sys/syslog.h> |
169 | #include <sys/pool.h> |
170 | #include <sys/domain.h> |
171 | #include <sys/kernel.h> |
172 | #ifdef TCP_SIGNATURE |
173 | #include <sys/md5.h> |
174 | #endif |
175 | #include <sys/lwp.h> /* for lwp0 */ |
176 | #include <sys/cprng.h> |
177 | |
178 | #include <net/if.h> |
179 | #include <net/if_types.h> |
180 | |
181 | #include <netinet/in.h> |
182 | #include <netinet/in_systm.h> |
183 | #include <netinet/ip.h> |
184 | #include <netinet/in_pcb.h> |
185 | #include <netinet/in_var.h> |
186 | #include <netinet/ip_var.h> |
187 | #include <netinet/in_offload.h> |
188 | |
189 | #ifdef INET6 |
190 | #ifndef INET |
191 | #include <netinet/in.h> |
192 | #endif |
193 | #include <netinet/ip6.h> |
194 | #include <netinet6/ip6_var.h> |
195 | #include <netinet6/in6_pcb.h> |
196 | #include <netinet6/ip6_var.h> |
197 | #include <netinet6/in6_var.h> |
198 | #include <netinet/icmp6.h> |
199 | #include <netinet6/nd6.h> |
200 | #ifdef TCP_SIGNATURE |
201 | #include <netinet6/scope6_var.h> |
202 | #endif |
203 | #endif |
204 | |
205 | #ifndef INET6 |
206 | /* always need ip6.h for IP6_EXTHDR_GET */ |
207 | #include <netinet/ip6.h> |
208 | #endif |
209 | |
210 | #include <netinet/tcp.h> |
211 | #include <netinet/tcp_fsm.h> |
212 | #include <netinet/tcp_seq.h> |
213 | #include <netinet/tcp_timer.h> |
214 | #include <netinet/tcp_var.h> |
215 | #include <netinet/tcp_private.h> |
216 | #include <netinet/tcpip.h> |
217 | #include <netinet/tcp_congctl.h> |
218 | #include <netinet/tcp_debug.h> |
219 | |
220 | #ifdef INET6 |
221 | #include "faith.h" |
222 | #if defined(NFAITH) && NFAITH > 0 |
223 | #include <net/if_faith.h> |
224 | #endif |
225 | #endif /* INET6 */ |
226 | |
227 | #ifdef IPSEC |
228 | #include <netipsec/ipsec.h> |
229 | #include <netipsec/ipsec_var.h> |
230 | #include <netipsec/ipsec_private.h> |
231 | #include <netipsec/key.h> |
232 | #ifdef INET6 |
233 | #include <netipsec/ipsec6.h> |
234 | #endif |
235 | #endif /* IPSEC*/ |
236 | |
237 | #include <netinet/tcp_vtw.h> |
238 | |
239 | int tcprexmtthresh = 3; |
240 | int tcp_log_refused; |
241 | |
242 | int tcp_do_autorcvbuf = 1; |
243 | int tcp_autorcvbuf_inc = 16 * 1024; |
244 | int tcp_autorcvbuf_max = 256 * 1024; |
245 | int tcp_msl = (TCPTV_MSL / PR_SLOWHZ); |
246 | |
247 | static int tcp_rst_ppslim_count = 0; |
248 | static struct timeval tcp_rst_ppslim_last; |
249 | static int tcp_ackdrop_ppslim_count = 0; |
250 | static struct timeval tcp_ackdrop_ppslim_last; |
251 | |
252 | #define TCP_PAWS_IDLE (24U * 24 * 60 * 60 * PR_SLOWHZ) |
253 | |
254 | /* for modulo comparisons of timestamps */ |
255 | #define TSTMP_LT(a,b) ((int)((a)-(b)) < 0) |
256 | #define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0) |
257 | |
258 | /* |
259 | * Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. |
260 | */ |
261 | #ifdef INET6 |
262 | static inline void |
263 | nd6_hint(struct tcpcb *tp) |
264 | { |
265 | struct rtentry *rt; |
266 | |
267 | if (tp != NULL && tp->t_in6pcb != NULL && tp->t_family == AF_INET6 && |
268 | (rt = rtcache_validate(&tp->t_in6pcb->in6p_route)) != NULL) |
269 | nd6_nud_hint(rt); |
270 | } |
271 | #else |
272 | static inline void |
273 | nd6_hint(struct tcpcb *tp) |
274 | { |
275 | } |
276 | #endif |
277 | |
278 | /* |
279 | * Compute ACK transmission behavior. Delay the ACK unless |
280 | * we have already delayed an ACK (must send an ACK every two segments). |
281 | * We also ACK immediately if we received a PUSH and the ACK-on-PUSH |
282 | * option is enabled. |
283 | */ |
284 | static void |
285 | tcp_setup_ack(struct tcpcb *tp, const struct tcphdr *th) |
286 | { |
287 | |
288 | if (tp->t_flags & TF_DELACK || |
289 | (tcp_ack_on_push && th->th_flags & TH_PUSH)) |
290 | tp->t_flags |= TF_ACKNOW; |
291 | else |
292 | TCP_SET_DELACK(tp); |
293 | } |
294 | |
295 | static void |
296 | icmp_check(struct tcpcb *tp, const struct tcphdr *th, int acked) |
297 | { |
298 | |
299 | /* |
300 | * If we had a pending ICMP message that refers to data that have |
301 | * just been acknowledged, disregard the recorded ICMP message. |
302 | */ |
303 | if ((tp->t_flags & TF_PMTUD_PEND) && |
304 | SEQ_GT(th->th_ack, tp->t_pmtud_th_seq)) |
305 | tp->t_flags &= ~TF_PMTUD_PEND; |
306 | |
307 | /* |
308 | * Keep track of the largest chunk of data |
309 | * acknowledged since last PMTU update |
310 | */ |
311 | if (tp->t_pmtud_mss_acked < acked) |
312 | tp->t_pmtud_mss_acked = acked; |
313 | } |
314 | |
315 | /* |
316 | * Convert TCP protocol fields to host order for easier processing. |
317 | */ |
318 | static void |
319 | tcp_fields_to_host(struct tcphdr *th) |
320 | { |
321 | |
322 | NTOHL(th->th_seq); |
323 | NTOHL(th->th_ack); |
324 | NTOHS(th->th_win); |
325 | NTOHS(th->th_urp); |
326 | } |
327 | |
328 | /* |
329 | * ... and reverse the above. |
330 | */ |
331 | static void |
332 | tcp_fields_to_net(struct tcphdr *th) |
333 | { |
334 | |
335 | HTONL(th->th_seq); |
336 | HTONL(th->th_ack); |
337 | HTONS(th->th_win); |
338 | HTONS(th->th_urp); |
339 | } |
340 | |
341 | #ifdef TCP_CSUM_COUNTERS |
342 | #include <sys/device.h> |
343 | |
344 | #if defined(INET) |
345 | extern struct evcnt tcp_hwcsum_ok; |
346 | extern struct evcnt tcp_hwcsum_bad; |
347 | extern struct evcnt tcp_hwcsum_data; |
348 | extern struct evcnt tcp_swcsum; |
349 | #endif /* defined(INET) */ |
350 | #if defined(INET6) |
351 | extern struct evcnt tcp6_hwcsum_ok; |
352 | extern struct evcnt tcp6_hwcsum_bad; |
353 | extern struct evcnt tcp6_hwcsum_data; |
354 | extern struct evcnt tcp6_swcsum; |
355 | #endif /* defined(INET6) */ |
356 | |
357 | #define TCP_CSUM_COUNTER_INCR(ev) (ev)->ev_count++ |
358 | |
359 | #else |
360 | |
361 | #define TCP_CSUM_COUNTER_INCR(ev) /* nothing */ |
362 | |
363 | #endif /* TCP_CSUM_COUNTERS */ |
364 | |
365 | #ifdef TCP_REASS_COUNTERS |
366 | #include <sys/device.h> |
367 | |
368 | extern struct evcnt tcp_reass_; |
369 | extern struct evcnt tcp_reass_empty; |
370 | extern struct evcnt tcp_reass_iteration[8]; |
371 | extern struct evcnt tcp_reass_prependfirst; |
372 | extern struct evcnt tcp_reass_prepend; |
373 | extern struct evcnt tcp_reass_insert; |
374 | extern struct evcnt tcp_reass_inserttail; |
375 | extern struct evcnt tcp_reass_append; |
376 | extern struct evcnt tcp_reass_appendtail; |
377 | extern struct evcnt tcp_reass_overlaptail; |
378 | extern struct evcnt tcp_reass_overlapfront; |
379 | extern struct evcnt tcp_reass_segdup; |
380 | extern struct evcnt tcp_reass_fragdup; |
381 | |
382 | #define TCP_REASS_COUNTER_INCR(ev) (ev)->ev_count++ |
383 | |
384 | #else |
385 | |
386 | #define TCP_REASS_COUNTER_INCR(ev) /* nothing */ |
387 | |
388 | #endif /* TCP_REASS_COUNTERS */ |
389 | |
390 | static int tcp_reass(struct tcpcb *, const struct tcphdr *, struct mbuf *, |
391 | int *); |
392 | static int tcp_dooptions(struct tcpcb *, const u_char *, int, |
393 | struct tcphdr *, struct mbuf *, int, struct tcp_opt_info *); |
394 | |
395 | #ifdef INET |
396 | static void tcp4_log_refused(const struct ip *, const struct tcphdr *); |
397 | #endif |
398 | #ifdef INET6 |
399 | static void tcp6_log_refused(const struct ip6_hdr *, const struct tcphdr *); |
400 | #endif |
401 | |
402 | #define TRAVERSE(x) while ((x)->m_next) (x) = (x)->m_next |
403 | |
404 | #if defined(MBUFTRACE) |
405 | struct mowner tcp_reass_mowner = MOWNER_INIT("tcp" , "reass" ); |
406 | #endif /* defined(MBUFTRACE) */ |
407 | |
408 | static struct pool tcpipqent_pool; |
409 | |
410 | void |
411 | tcpipqent_init(void) |
412 | { |
413 | |
414 | pool_init(&tcpipqent_pool, sizeof(struct ipqent), 0, 0, 0, "tcpipqepl" , |
415 | NULL, IPL_VM); |
416 | } |
417 | |
418 | struct ipqent * |
419 | tcpipqent_alloc(void) |
420 | { |
421 | struct ipqent *ipqe; |
422 | int s; |
423 | |
424 | s = splvm(); |
425 | ipqe = pool_get(&tcpipqent_pool, PR_NOWAIT); |
426 | splx(s); |
427 | |
428 | return ipqe; |
429 | } |
430 | |
431 | void |
432 | tcpipqent_free(struct ipqent *ipqe) |
433 | { |
434 | int s; |
435 | |
436 | s = splvm(); |
437 | pool_put(&tcpipqent_pool, ipqe); |
438 | splx(s); |
439 | } |
440 | |
441 | static int |
442 | tcp_reass(struct tcpcb *tp, const struct tcphdr *th, struct mbuf *m, int *tlen) |
443 | { |
444 | struct ipqent *p, *q, *nq, *tiqe = NULL; |
445 | struct socket *so = NULL; |
446 | int pkt_flags; |
447 | tcp_seq pkt_seq; |
448 | unsigned pkt_len; |
449 | u_long rcvpartdupbyte = 0; |
450 | u_long rcvoobyte; |
451 | #ifdef TCP_REASS_COUNTERS |
452 | u_int count = 0; |
453 | #endif |
454 | uint64_t *tcps; |
455 | |
456 | if (tp->t_inpcb) |
457 | so = tp->t_inpcb->inp_socket; |
458 | #ifdef INET6 |
459 | else if (tp->t_in6pcb) |
460 | so = tp->t_in6pcb->in6p_socket; |
461 | #endif |
462 | |
463 | TCP_REASS_LOCK_CHECK(tp); |
464 | |
465 | /* |
466 | * Call with th==0 after become established to |
467 | * force pre-ESTABLISHED data up to user socket. |
468 | */ |
469 | if (th == 0) |
470 | goto present; |
471 | |
472 | m_claimm(m, &tcp_reass_mowner); |
473 | |
474 | rcvoobyte = *tlen; |
475 | /* |
476 | * Copy these to local variables because the tcpiphdr |
477 | * gets munged while we are collapsing mbufs. |
478 | */ |
479 | pkt_seq = th->th_seq; |
480 | pkt_len = *tlen; |
481 | pkt_flags = th->th_flags; |
482 | |
483 | TCP_REASS_COUNTER_INCR(&tcp_reass_); |
484 | |
485 | if ((p = TAILQ_LAST(&tp->segq, ipqehead)) != NULL) { |
486 | /* |
487 | * When we miss a packet, the vast majority of time we get |
488 | * packets that follow it in order. So optimize for that. |
489 | */ |
490 | if (pkt_seq == p->ipqe_seq + p->ipqe_len) { |
491 | p->ipqe_len += pkt_len; |
492 | p->ipqe_flags |= pkt_flags; |
493 | m_cat(p->ipre_mlast, m); |
494 | TRAVERSE(p->ipre_mlast); |
495 | m = NULL; |
496 | tiqe = p; |
497 | TAILQ_REMOVE(&tp->timeq, p, ipqe_timeq); |
498 | TCP_REASS_COUNTER_INCR(&tcp_reass_appendtail); |
499 | goto skip_replacement; |
500 | } |
501 | /* |
502 | * While we're here, if the pkt is completely beyond |
503 | * anything we have, just insert it at the tail. |
504 | */ |
505 | if (SEQ_GT(pkt_seq, p->ipqe_seq + p->ipqe_len)) { |
506 | TCP_REASS_COUNTER_INCR(&tcp_reass_inserttail); |
507 | goto insert_it; |
508 | } |
509 | } |
510 | |
511 | q = TAILQ_FIRST(&tp->segq); |
512 | |
513 | if (q != NULL) { |
514 | /* |
515 | * If this segment immediately precedes the first out-of-order |
516 | * block, simply slap the segment in front of it and (mostly) |
517 | * skip the complicated logic. |
518 | */ |
519 | if (pkt_seq + pkt_len == q->ipqe_seq) { |
520 | q->ipqe_seq = pkt_seq; |
521 | q->ipqe_len += pkt_len; |
522 | q->ipqe_flags |= pkt_flags; |
523 | m_cat(m, q->ipqe_m); |
524 | q->ipqe_m = m; |
525 | q->ipre_mlast = m; /* last mbuf may have changed */ |
526 | TRAVERSE(q->ipre_mlast); |
527 | tiqe = q; |
528 | TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); |
529 | TCP_REASS_COUNTER_INCR(&tcp_reass_prependfirst); |
530 | goto skip_replacement; |
531 | } |
532 | } else { |
533 | TCP_REASS_COUNTER_INCR(&tcp_reass_empty); |
534 | } |
535 | |
536 | /* |
537 | * Find a segment which begins after this one does. |
538 | */ |
539 | for (p = NULL; q != NULL; q = nq) { |
540 | nq = TAILQ_NEXT(q, ipqe_q); |
541 | #ifdef TCP_REASS_COUNTERS |
542 | count++; |
543 | #endif |
544 | /* |
545 | * If the received segment is just right after this |
546 | * fragment, merge the two together and then check |
547 | * for further overlaps. |
548 | */ |
549 | if (q->ipqe_seq + q->ipqe_len == pkt_seq) { |
550 | #ifdef TCPREASS_DEBUG |
551 | printf("tcp_reass[%p]: concat %u:%u(%u) to %u:%u(%u)\n" , |
552 | tp, pkt_seq, pkt_seq + pkt_len, pkt_len, |
553 | q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len); |
554 | #endif |
555 | pkt_len += q->ipqe_len; |
556 | pkt_flags |= q->ipqe_flags; |
557 | pkt_seq = q->ipqe_seq; |
558 | m_cat(q->ipre_mlast, m); |
559 | TRAVERSE(q->ipre_mlast); |
560 | m = q->ipqe_m; |
561 | TCP_REASS_COUNTER_INCR(&tcp_reass_append); |
562 | goto free_ipqe; |
563 | } |
564 | /* |
565 | * If the received segment is completely past this |
566 | * fragment, we need to go the next fragment. |
567 | */ |
568 | if (SEQ_LT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { |
569 | p = q; |
570 | continue; |
571 | } |
572 | /* |
573 | * If the fragment is past the received segment, |
574 | * it (or any following) can't be concatenated. |
575 | */ |
576 | if (SEQ_GT(q->ipqe_seq, pkt_seq + pkt_len)) { |
577 | TCP_REASS_COUNTER_INCR(&tcp_reass_insert); |
578 | break; |
579 | } |
580 | |
581 | /* |
582 | * We've received all the data in this segment before. |
583 | * mark it as a duplicate and return. |
584 | */ |
585 | if (SEQ_LEQ(q->ipqe_seq, pkt_seq) && |
586 | SEQ_GEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { |
587 | tcps = TCP_STAT_GETREF(); |
588 | tcps[TCP_STAT_RCVDUPPACK]++; |
589 | tcps[TCP_STAT_RCVDUPBYTE] += pkt_len; |
590 | TCP_STAT_PUTREF(); |
591 | tcp_new_dsack(tp, pkt_seq, pkt_len); |
592 | m_freem(m); |
593 | if (tiqe != NULL) { |
594 | tcpipqent_free(tiqe); |
595 | } |
596 | TCP_REASS_COUNTER_INCR(&tcp_reass_segdup); |
597 | goto out; |
598 | } |
599 | /* |
600 | * Received segment completely overlaps this fragment |
601 | * so we drop the fragment (this keeps the temporal |
602 | * ordering of segments correct). |
603 | */ |
604 | if (SEQ_GEQ(q->ipqe_seq, pkt_seq) && |
605 | SEQ_LEQ(q->ipqe_seq + q->ipqe_len, pkt_seq + pkt_len)) { |
606 | rcvpartdupbyte += q->ipqe_len; |
607 | m_freem(q->ipqe_m); |
608 | TCP_REASS_COUNTER_INCR(&tcp_reass_fragdup); |
609 | goto free_ipqe; |
610 | } |
611 | /* |
612 | * RX'ed segment extends past the end of the |
613 | * fragment. Drop the overlapping bytes. Then |
614 | * merge the fragment and segment then treat as |
615 | * a longer received packet. |
616 | */ |
617 | if (SEQ_LT(q->ipqe_seq, pkt_seq) && |
618 | SEQ_GT(q->ipqe_seq + q->ipqe_len, pkt_seq)) { |
619 | int overlap = q->ipqe_seq + q->ipqe_len - pkt_seq; |
620 | #ifdef TCPREASS_DEBUG |
621 | printf("tcp_reass[%p]: trim starting %d bytes of %u:%u(%u)\n" , |
622 | tp, overlap, |
623 | pkt_seq, pkt_seq + pkt_len, pkt_len); |
624 | #endif |
625 | m_adj(m, overlap); |
626 | rcvpartdupbyte += overlap; |
627 | m_cat(q->ipre_mlast, m); |
628 | TRAVERSE(q->ipre_mlast); |
629 | m = q->ipqe_m; |
630 | pkt_seq = q->ipqe_seq; |
631 | pkt_len += q->ipqe_len - overlap; |
632 | rcvoobyte -= overlap; |
633 | TCP_REASS_COUNTER_INCR(&tcp_reass_overlaptail); |
634 | goto free_ipqe; |
635 | } |
636 | /* |
637 | * RX'ed segment extends past the front of the |
638 | * fragment. Drop the overlapping bytes on the |
639 | * received packet. The packet will then be |
640 | * contatentated with this fragment a bit later. |
641 | */ |
642 | if (SEQ_GT(q->ipqe_seq, pkt_seq) && |
643 | SEQ_LT(q->ipqe_seq, pkt_seq + pkt_len)) { |
644 | int overlap = pkt_seq + pkt_len - q->ipqe_seq; |
645 | #ifdef TCPREASS_DEBUG |
646 | printf("tcp_reass[%p]: trim trailing %d bytes of %u:%u(%u)\n" , |
647 | tp, overlap, |
648 | pkt_seq, pkt_seq + pkt_len, pkt_len); |
649 | #endif |
650 | m_adj(m, -overlap); |
651 | pkt_len -= overlap; |
652 | rcvpartdupbyte += overlap; |
653 | TCP_REASS_COUNTER_INCR(&tcp_reass_overlapfront); |
654 | rcvoobyte -= overlap; |
655 | } |
656 | /* |
657 | * If the received segment immediates precedes this |
658 | * fragment then tack the fragment onto this segment |
659 | * and reinsert the data. |
660 | */ |
661 | if (q->ipqe_seq == pkt_seq + pkt_len) { |
662 | #ifdef TCPREASS_DEBUG |
663 | printf("tcp_reass[%p]: append %u:%u(%u) to %u:%u(%u)\n" , |
664 | tp, q->ipqe_seq, q->ipqe_seq + q->ipqe_len, q->ipqe_len, |
665 | pkt_seq, pkt_seq + pkt_len, pkt_len); |
666 | #endif |
667 | pkt_len += q->ipqe_len; |
668 | pkt_flags |= q->ipqe_flags; |
669 | m_cat(m, q->ipqe_m); |
670 | TAILQ_REMOVE(&tp->segq, q, ipqe_q); |
671 | TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); |
672 | tp->t_segqlen--; |
673 | KASSERT(tp->t_segqlen >= 0); |
674 | KASSERT(tp->t_segqlen != 0 || |
675 | (TAILQ_EMPTY(&tp->segq) && |
676 | TAILQ_EMPTY(&tp->timeq))); |
677 | if (tiqe == NULL) { |
678 | tiqe = q; |
679 | } else { |
680 | tcpipqent_free(q); |
681 | } |
682 | TCP_REASS_COUNTER_INCR(&tcp_reass_prepend); |
683 | break; |
684 | } |
685 | /* |
686 | * If the fragment is before the segment, remember it. |
687 | * When this loop is terminated, p will contain the |
688 | * pointer to fragment that is right before the received |
689 | * segment. |
690 | */ |
691 | if (SEQ_LEQ(q->ipqe_seq, pkt_seq)) |
692 | p = q; |
693 | |
694 | continue; |
695 | |
696 | /* |
697 | * This is a common operation. It also will allow |
698 | * to save doing a malloc/free in most instances. |
699 | */ |
700 | free_ipqe: |
701 | TAILQ_REMOVE(&tp->segq, q, ipqe_q); |
702 | TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); |
703 | tp->t_segqlen--; |
704 | KASSERT(tp->t_segqlen >= 0); |
705 | KASSERT(tp->t_segqlen != 0 || |
706 | (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); |
707 | if (tiqe == NULL) { |
708 | tiqe = q; |
709 | } else { |
710 | tcpipqent_free(q); |
711 | } |
712 | } |
713 | |
714 | #ifdef TCP_REASS_COUNTERS |
715 | if (count > 7) |
716 | TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[0]); |
717 | else if (count > 0) |
718 | TCP_REASS_COUNTER_INCR(&tcp_reass_iteration[count]); |
719 | #endif |
720 | |
721 | insert_it: |
722 | |
723 | /* |
724 | * Allocate a new queue entry since the received segment did not |
725 | * collapse onto any other out-of-order block; thus we are allocating |
726 | * a new block. If it had collapsed, tiqe would not be NULL and |
727 | * we would be reusing it. |
728 | * XXX If we can't, just drop the packet. XXX |
729 | */ |
730 | if (tiqe == NULL) { |
731 | tiqe = tcpipqent_alloc(); |
732 | if (tiqe == NULL) { |
733 | TCP_STATINC(TCP_STAT_RCVMEMDROP); |
734 | m_freem(m); |
735 | goto out; |
736 | } |
737 | } |
738 | |
739 | /* |
740 | * Update the counters. |
741 | */ |
742 | tp->t_rcvoopack++; |
743 | tcps = TCP_STAT_GETREF(); |
744 | tcps[TCP_STAT_RCVOOPACK]++; |
745 | tcps[TCP_STAT_RCVOOBYTE] += rcvoobyte; |
746 | if (rcvpartdupbyte) { |
747 | tcps[TCP_STAT_RCVPARTDUPPACK]++; |
748 | tcps[TCP_STAT_RCVPARTDUPBYTE] += rcvpartdupbyte; |
749 | } |
750 | TCP_STAT_PUTREF(); |
751 | |
752 | /* |
753 | * Insert the new fragment queue entry into both queues. |
754 | */ |
755 | tiqe->ipqe_m = m; |
756 | tiqe->ipre_mlast = m; |
757 | tiqe->ipqe_seq = pkt_seq; |
758 | tiqe->ipqe_len = pkt_len; |
759 | tiqe->ipqe_flags = pkt_flags; |
760 | if (p == NULL) { |
761 | TAILQ_INSERT_HEAD(&tp->segq, tiqe, ipqe_q); |
762 | #ifdef TCPREASS_DEBUG |
763 | if (tiqe->ipqe_seq != tp->rcv_nxt) |
764 | printf("tcp_reass[%p]: insert %u:%u(%u) at front\n" , |
765 | tp, pkt_seq, pkt_seq + pkt_len, pkt_len); |
766 | #endif |
767 | } else { |
768 | TAILQ_INSERT_AFTER(&tp->segq, p, tiqe, ipqe_q); |
769 | #ifdef TCPREASS_DEBUG |
770 | printf("tcp_reass[%p]: insert %u:%u(%u) after %u:%u(%u)\n" , |
771 | tp, pkt_seq, pkt_seq + pkt_len, pkt_len, |
772 | p->ipqe_seq, p->ipqe_seq + p->ipqe_len, p->ipqe_len); |
773 | #endif |
774 | } |
775 | tp->t_segqlen++; |
776 | |
777 | skip_replacement: |
778 | |
779 | TAILQ_INSERT_HEAD(&tp->timeq, tiqe, ipqe_timeq); |
780 | |
781 | present: |
782 | /* |
783 | * Present data to user, advancing rcv_nxt through |
784 | * completed sequence space. |
785 | */ |
786 | if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) |
787 | goto out; |
788 | q = TAILQ_FIRST(&tp->segq); |
789 | if (q == NULL || q->ipqe_seq != tp->rcv_nxt) |
790 | goto out; |
791 | if (tp->t_state == TCPS_SYN_RECEIVED && q->ipqe_len) |
792 | goto out; |
793 | |
794 | tp->rcv_nxt += q->ipqe_len; |
795 | pkt_flags = q->ipqe_flags & TH_FIN; |
796 | nd6_hint(tp); |
797 | |
798 | TAILQ_REMOVE(&tp->segq, q, ipqe_q); |
799 | TAILQ_REMOVE(&tp->timeq, q, ipqe_timeq); |
800 | tp->t_segqlen--; |
801 | KASSERT(tp->t_segqlen >= 0); |
802 | KASSERT(tp->t_segqlen != 0 || |
803 | (TAILQ_EMPTY(&tp->segq) && TAILQ_EMPTY(&tp->timeq))); |
804 | if (so->so_state & SS_CANTRCVMORE) |
805 | m_freem(q->ipqe_m); |
806 | else |
807 | sbappendstream(&so->so_rcv, q->ipqe_m); |
808 | tcpipqent_free(q); |
809 | TCP_REASS_UNLOCK(tp); |
810 | sorwakeup(so); |
811 | return (pkt_flags); |
812 | out: |
813 | TCP_REASS_UNLOCK(tp); |
814 | return (0); |
815 | } |
816 | |
817 | #ifdef INET6 |
818 | int |
819 | tcp6_input(struct mbuf **mp, int *offp, int proto) |
820 | { |
821 | struct mbuf *m = *mp; |
822 | |
823 | /* |
824 | * draft-itojun-ipv6-tcp-to-anycast |
825 | * better place to put this in? |
826 | */ |
827 | if (m->m_flags & M_ANYCAST6) { |
828 | struct ip6_hdr *ip6; |
829 | if (m->m_len < sizeof(struct ip6_hdr)) { |
830 | if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) { |
831 | TCP_STATINC(TCP_STAT_RCVSHORT); |
832 | return IPPROTO_DONE; |
833 | } |
834 | } |
835 | ip6 = mtod(m, struct ip6_hdr *); |
836 | icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR, |
837 | (char *)&ip6->ip6_dst - (char *)ip6); |
838 | return IPPROTO_DONE; |
839 | } |
840 | |
841 | tcp_input(m, *offp, proto); |
842 | return IPPROTO_DONE; |
843 | } |
844 | #endif |
845 | |
846 | #ifdef INET |
847 | static void |
848 | tcp4_log_refused(const struct ip *ip, const struct tcphdr *th) |
849 | { |
850 | char src[INET_ADDRSTRLEN]; |
851 | char dst[INET_ADDRSTRLEN]; |
852 | |
853 | if (ip) { |
854 | in_print(src, sizeof(src), &ip->ip_src); |
855 | in_print(dst, sizeof(dst), &ip->ip_dst); |
856 | } |
857 | else { |
858 | strlcpy(src, "(unknown)" , sizeof(src)); |
859 | strlcpy(dst, "(unknown)" , sizeof(dst)); |
860 | } |
861 | log(LOG_INFO, |
862 | "Connection attempt to TCP %s:%d from %s:%d\n" , |
863 | dst, ntohs(th->th_dport), |
864 | src, ntohs(th->th_sport)); |
865 | } |
866 | #endif |
867 | |
868 | #ifdef INET6 |
869 | static void |
870 | tcp6_log_refused(const struct ip6_hdr *ip6, const struct tcphdr *th) |
871 | { |
872 | char src[INET6_ADDRSTRLEN]; |
873 | char dst[INET6_ADDRSTRLEN]; |
874 | |
875 | if (ip6) { |
876 | in6_print(src, sizeof(src), &ip6->ip6_src); |
877 | in6_print(dst, sizeof(dst), &ip6->ip6_dst); |
878 | } |
879 | else { |
880 | strlcpy(src, "(unknown v6)" , sizeof(src)); |
881 | strlcpy(dst, "(unknown v6)" , sizeof(dst)); |
882 | } |
883 | log(LOG_INFO, |
884 | "Connection attempt to TCP [%s]:%d from [%s]:%d\n" , |
885 | dst, ntohs(th->th_dport), |
886 | src, ntohs(th->th_sport)); |
887 | } |
888 | #endif |
889 | |
890 | /* |
891 | * Checksum extended TCP header and data. |
892 | */ |
893 | int |
894 | tcp_input_checksum(int af, struct mbuf *m, const struct tcphdr *th, |
895 | int toff, int off, int tlen) |
896 | { |
897 | struct ifnet *rcvif; |
898 | int s; |
899 | |
900 | /* |
901 | * XXX it's better to record and check if this mbuf is |
902 | * already checked. |
903 | */ |
904 | |
905 | rcvif = m_get_rcvif(m, &s); |
906 | |
907 | switch (af) { |
908 | #ifdef INET |
909 | case AF_INET: |
910 | switch (m->m_pkthdr.csum_flags & |
911 | ((rcvif->if_csum_flags_rx & M_CSUM_TCPv4) | |
912 | M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { |
913 | case M_CSUM_TCPv4|M_CSUM_TCP_UDP_BAD: |
914 | TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_bad); |
915 | goto badcsum; |
916 | |
917 | case M_CSUM_TCPv4|M_CSUM_DATA: { |
918 | u_int32_t hw_csum = m->m_pkthdr.csum_data; |
919 | |
920 | TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_data); |
921 | if (m->m_pkthdr.csum_flags & M_CSUM_NO_PSEUDOHDR) { |
922 | const struct ip *ip = |
923 | mtod(m, const struct ip *); |
924 | |
925 | hw_csum = in_cksum_phdr(ip->ip_src.s_addr, |
926 | ip->ip_dst.s_addr, |
927 | htons(hw_csum + tlen + off + IPPROTO_TCP)); |
928 | } |
929 | if ((hw_csum ^ 0xffff) != 0) |
930 | goto badcsum; |
931 | break; |
932 | } |
933 | |
934 | case M_CSUM_TCPv4: |
935 | /* Checksum was okay. */ |
936 | TCP_CSUM_COUNTER_INCR(&tcp_hwcsum_ok); |
937 | break; |
938 | |
939 | default: |
940 | /* |
941 | * Must compute it ourselves. Maybe skip checksum |
942 | * on loopback interfaces. |
943 | */ |
944 | if (__predict_true(!(rcvif->if_flags & IFF_LOOPBACK) || |
945 | tcp_do_loopback_cksum)) { |
946 | TCP_CSUM_COUNTER_INCR(&tcp_swcsum); |
947 | if (in4_cksum(m, IPPROTO_TCP, toff, |
948 | tlen + off) != 0) |
949 | goto badcsum; |
950 | } |
951 | break; |
952 | } |
953 | break; |
954 | #endif /* INET4 */ |
955 | |
956 | #ifdef INET6 |
957 | case AF_INET6: |
958 | switch (m->m_pkthdr.csum_flags & |
959 | ((rcvif->if_csum_flags_rx & M_CSUM_TCPv6) | |
960 | M_CSUM_TCP_UDP_BAD | M_CSUM_DATA)) { |
961 | case M_CSUM_TCPv6|M_CSUM_TCP_UDP_BAD: |
962 | TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_bad); |
963 | goto badcsum; |
964 | |
965 | #if 0 /* notyet */ |
966 | case M_CSUM_TCPv6|M_CSUM_DATA: |
967 | #endif |
968 | |
969 | case M_CSUM_TCPv6: |
970 | /* Checksum was okay. */ |
971 | TCP_CSUM_COUNTER_INCR(&tcp6_hwcsum_ok); |
972 | break; |
973 | |
974 | default: |
975 | /* |
976 | * Must compute it ourselves. Maybe skip checksum |
977 | * on loopback interfaces. |
978 | */ |
979 | if (__predict_true((m->m_flags & M_LOOP) == 0 || |
980 | tcp_do_loopback_cksum)) { |
981 | TCP_CSUM_COUNTER_INCR(&tcp6_swcsum); |
982 | if (in6_cksum(m, IPPROTO_TCP, toff, |
983 | tlen + off) != 0) |
984 | goto badcsum; |
985 | } |
986 | } |
987 | break; |
988 | #endif /* INET6 */ |
989 | } |
990 | m_put_rcvif(rcvif, &s); |
991 | |
992 | return 0; |
993 | |
994 | badcsum: |
995 | m_put_rcvif(rcvif, &s); |
996 | TCP_STATINC(TCP_STAT_RCVBADSUM); |
997 | return -1; |
998 | } |
999 | |
1000 | /* When a packet arrives addressed to a vestigial tcpbp, we |
1001 | * nevertheless have to respond to it per the spec. |
1002 | */ |
1003 | static void tcp_vtw_input(struct tcphdr *th, vestigial_inpcb_t *vp, |
1004 | struct mbuf *m, int tlen, int multicast) |
1005 | { |
1006 | int tiflags; |
1007 | int todrop; |
1008 | uint32_t t_flags = 0; |
1009 | uint64_t *tcps; |
1010 | |
1011 | tiflags = th->th_flags; |
1012 | todrop = vp->rcv_nxt - th->th_seq; |
1013 | |
1014 | if (todrop > 0) { |
1015 | if (tiflags & TH_SYN) { |
1016 | tiflags &= ~TH_SYN; |
1017 | ++th->th_seq; |
1018 | if (th->th_urp > 1) |
1019 | --th->th_urp; |
1020 | else { |
1021 | tiflags &= ~TH_URG; |
1022 | th->th_urp = 0; |
1023 | } |
1024 | --todrop; |
1025 | } |
1026 | if (todrop > tlen || |
1027 | (todrop == tlen && (tiflags & TH_FIN) == 0)) { |
1028 | /* |
1029 | * Any valid FIN or RST must be to the left of the |
1030 | * window. At this point the FIN or RST must be a |
1031 | * duplicate or out of sequence; drop it. |
1032 | */ |
1033 | if (tiflags & TH_RST) |
1034 | goto drop; |
1035 | tiflags &= ~(TH_FIN|TH_RST); |
1036 | /* |
1037 | * Send an ACK to resynchronize and drop any data. |
1038 | * But keep on processing for RST or ACK. |
1039 | */ |
1040 | t_flags |= TF_ACKNOW; |
1041 | todrop = tlen; |
1042 | tcps = TCP_STAT_GETREF(); |
1043 | tcps[TCP_STAT_RCVDUPPACK] += 1; |
1044 | tcps[TCP_STAT_RCVDUPBYTE] += todrop; |
1045 | TCP_STAT_PUTREF(); |
1046 | } else if ((tiflags & TH_RST) |
1047 | && th->th_seq != vp->rcv_nxt) { |
1048 | /* |
1049 | * Test for reset before adjusting the sequence |
1050 | * number for overlapping data. |
1051 | */ |
1052 | goto dropafterack_ratelim; |
1053 | } else { |
1054 | tcps = TCP_STAT_GETREF(); |
1055 | tcps[TCP_STAT_RCVPARTDUPPACK] += 1; |
1056 | tcps[TCP_STAT_RCVPARTDUPBYTE] += todrop; |
1057 | TCP_STAT_PUTREF(); |
1058 | } |
1059 | |
1060 | // tcp_new_dsack(tp, th->th_seq, todrop); |
1061 | // hdroptlen += todrop; /*drop from head afterwards*/ |
1062 | |
1063 | th->th_seq += todrop; |
1064 | tlen -= todrop; |
1065 | |
1066 | if (th->th_urp > todrop) |
1067 | th->th_urp -= todrop; |
1068 | else { |
1069 | tiflags &= ~TH_URG; |
1070 | th->th_urp = 0; |
1071 | } |
1072 | } |
1073 | |
1074 | /* |
1075 | * If new data are received on a connection after the |
1076 | * user processes are gone, then RST the other end. |
1077 | */ |
1078 | if (tlen) { |
1079 | TCP_STATINC(TCP_STAT_RCVAFTERCLOSE); |
1080 | goto dropwithreset; |
1081 | } |
1082 | |
1083 | /* |
1084 | * If segment ends after window, drop trailing data |
1085 | * (and PUSH and FIN); if nothing left, just ACK. |
1086 | */ |
1087 | todrop = (th->th_seq + tlen) - (vp->rcv_nxt+vp->rcv_wnd); |
1088 | |
1089 | if (todrop > 0) { |
1090 | TCP_STATINC(TCP_STAT_RCVPACKAFTERWIN); |
1091 | if (todrop >= tlen) { |
1092 | /* |
1093 | * The segment actually starts after the window. |
1094 | * th->th_seq + tlen - vp->rcv_nxt - vp->rcv_wnd >= tlen |
1095 | * th->th_seq - vp->rcv_nxt - vp->rcv_wnd >= 0 |
1096 | * th->th_seq >= vp->rcv_nxt + vp->rcv_wnd |
1097 | */ |
1098 | TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, tlen); |
1099 | /* |
1100 | * If a new connection request is received |
1101 | * while in TIME_WAIT, drop the old connection |
1102 | * and start over if the sequence numbers |
1103 | * are above the previous ones. |
1104 | */ |
1105 | if ((tiflags & TH_SYN) |
1106 | && SEQ_GT(th->th_seq, vp->rcv_nxt)) { |
1107 | /* We only support this in the !NOFDREF case, which |
1108 | * is to say: not here. |
1109 | */ |
1110 | goto dropwithreset; |
1111 | } |
1112 | /* |
1113 | * If window is closed can only take segments at |
1114 | * window edge, and have to drop data and PUSH from |
1115 | * incoming segments. Continue processing, but |
1116 | * remember to ack. Otherwise, drop segment |
1117 | * and (if not RST) ack. |
1118 | */ |
1119 | if (vp->rcv_wnd == 0 && th->th_seq == vp->rcv_nxt) { |
1120 | t_flags |= TF_ACKNOW; |
1121 | TCP_STATINC(TCP_STAT_RCVWINPROBE); |
1122 | } else |
1123 | goto dropafterack; |
1124 | } else |
1125 | TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, todrop); |
1126 | m_adj(m, -todrop); |
1127 | tlen -= todrop; |
1128 | tiflags &= ~(TH_PUSH|TH_FIN); |
1129 | } |
1130 | |
1131 | if (tiflags & TH_RST) { |
1132 | if (th->th_seq != vp->rcv_nxt) |
1133 | goto dropafterack_ratelim; |
1134 | |
1135 | vtw_del(vp->ctl, vp->vtw); |
1136 | goto drop; |
1137 | } |
1138 | |
1139 | /* |
1140 | * If the ACK bit is off we drop the segment and return. |
1141 | */ |
1142 | if ((tiflags & TH_ACK) == 0) { |
1143 | if (t_flags & TF_ACKNOW) |
1144 | goto dropafterack; |
1145 | else |
1146 | goto drop; |
1147 | } |
1148 | |
1149 | /* |
1150 | * In TIME_WAIT state the only thing that should arrive |
1151 | * is a retransmission of the remote FIN. Acknowledge |
1152 | * it and restart the finack timer. |
1153 | */ |
1154 | vtw_restart(vp); |
1155 | goto dropafterack; |
1156 | |
1157 | dropafterack: |
1158 | /* |
1159 | * Generate an ACK dropping incoming segment if it occupies |
1160 | * sequence space, where the ACK reflects our state. |
1161 | */ |
1162 | if (tiflags & TH_RST) |
1163 | goto drop; |
1164 | goto dropafterack2; |
1165 | |
1166 | dropafterack_ratelim: |
1167 | /* |
1168 | * We may want to rate-limit ACKs against SYN/RST attack. |
1169 | */ |
1170 | if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count, |
1171 | tcp_ackdrop_ppslim) == 0) { |
1172 | /* XXX stat */ |
1173 | goto drop; |
1174 | } |
1175 | /* ...fall into dropafterack2... */ |
1176 | |
1177 | dropafterack2: |
1178 | (void)tcp_respond(0, m, m, th, th->th_seq + tlen, th->th_ack, |
1179 | TH_ACK); |
1180 | return; |
1181 | |
1182 | dropwithreset: |
1183 | /* |
1184 | * Generate a RST, dropping incoming segment. |
1185 | * Make ACK acceptable to originator of segment. |
1186 | */ |
1187 | if (tiflags & TH_RST) |
1188 | goto drop; |
1189 | |
1190 | if (tiflags & TH_ACK) |
1191 | tcp_respond(0, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); |
1192 | else { |
1193 | if (tiflags & TH_SYN) |
1194 | ++tlen; |
1195 | (void)tcp_respond(0, m, m, th, th->th_seq + tlen, (tcp_seq)0, |
1196 | TH_RST|TH_ACK); |
1197 | } |
1198 | return; |
1199 | drop: |
1200 | m_freem(m); |
1201 | } |
1202 | |
1203 | /* |
1204 | * TCP input routine, follows pages 65-76 of RFC 793 very closely. |
1205 | */ |
1206 | void |
1207 | tcp_input(struct mbuf *m, ...) |
1208 | { |
1209 | struct tcphdr *th; |
1210 | struct ip *ip; |
1211 | struct inpcb *inp; |
1212 | #ifdef INET6 |
1213 | struct ip6_hdr *ip6; |
1214 | struct in6pcb *in6p; |
1215 | #endif |
1216 | u_int8_t *optp = NULL; |
1217 | int optlen = 0; |
1218 | int len, tlen, toff, hdroptlen = 0; |
1219 | struct tcpcb *tp = 0; |
1220 | int tiflags; |
1221 | struct socket *so = NULL; |
1222 | int todrop, acked, ourfinisacked, needoutput = 0; |
1223 | bool dupseg; |
1224 | #ifdef TCP_DEBUG |
1225 | short ostate = 0; |
1226 | #endif |
1227 | u_long tiwin; |
1228 | struct tcp_opt_info opti; |
1229 | int off, iphlen; |
1230 | va_list ap; |
1231 | int af; /* af on the wire */ |
1232 | struct mbuf *tcp_saveti = NULL; |
1233 | uint32_t ts_rtt; |
1234 | uint8_t iptos; |
1235 | uint64_t *tcps; |
1236 | vestigial_inpcb_t vestige; |
1237 | |
1238 | vestige.valid = 0; |
1239 | |
1240 | MCLAIM(m, &tcp_rx_mowner); |
1241 | va_start(ap, m); |
1242 | toff = va_arg(ap, int); |
1243 | (void)va_arg(ap, int); /* ignore value, advance ap */ |
1244 | va_end(ap); |
1245 | |
1246 | TCP_STATINC(TCP_STAT_RCVTOTAL); |
1247 | |
1248 | memset(&opti, 0, sizeof(opti)); |
1249 | opti.ts_present = 0; |
1250 | opti.maxseg = 0; |
1251 | |
1252 | /* |
1253 | * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN. |
1254 | * |
1255 | * TCP is, by definition, unicast, so we reject all |
1256 | * multicast outright. |
1257 | * |
1258 | * Note, there are additional src/dst address checks in |
1259 | * the AF-specific code below. |
1260 | */ |
1261 | if (m->m_flags & (M_BCAST|M_MCAST)) { |
1262 | /* XXX stat */ |
1263 | goto drop; |
1264 | } |
1265 | #ifdef INET6 |
1266 | if (m->m_flags & M_ANYCAST6) { |
1267 | /* XXX stat */ |
1268 | goto drop; |
1269 | } |
1270 | #endif |
1271 | |
1272 | /* |
1273 | * Get IP and TCP header. |
1274 | * Note: IP leaves IP header in first mbuf. |
1275 | */ |
1276 | ip = mtod(m, struct ip *); |
1277 | switch (ip->ip_v) { |
1278 | #ifdef INET |
1279 | case 4: |
1280 | #ifdef INET6 |
1281 | ip6 = NULL; |
1282 | #endif |
1283 | af = AF_INET; |
1284 | iphlen = sizeof(struct ip); |
1285 | IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, |
1286 | sizeof(struct tcphdr)); |
1287 | if (th == NULL) { |
1288 | TCP_STATINC(TCP_STAT_RCVSHORT); |
1289 | return; |
1290 | } |
1291 | /* We do the checksum after PCB lookup... */ |
1292 | len = ntohs(ip->ip_len); |
1293 | tlen = len - toff; |
1294 | iptos = ip->ip_tos; |
1295 | break; |
1296 | #endif |
1297 | #ifdef INET6 |
1298 | case 6: |
1299 | ip = NULL; |
1300 | iphlen = sizeof(struct ip6_hdr); |
1301 | af = AF_INET6; |
1302 | ip6 = mtod(m, struct ip6_hdr *); |
1303 | IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, |
1304 | sizeof(struct tcphdr)); |
1305 | if (th == NULL) { |
1306 | TCP_STATINC(TCP_STAT_RCVSHORT); |
1307 | return; |
1308 | } |
1309 | |
1310 | /* Be proactive about malicious use of IPv4 mapped address */ |
1311 | if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) || |
1312 | IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) { |
1313 | /* XXX stat */ |
1314 | goto drop; |
1315 | } |
1316 | |
1317 | /* |
1318 | * Be proactive about unspecified IPv6 address in source. |
1319 | * As we use all-zero to indicate unbounded/unconnected pcb, |
1320 | * unspecified IPv6 address can be used to confuse us. |
1321 | * |
1322 | * Note that packets with unspecified IPv6 destination is |
1323 | * already dropped in ip6_input. |
1324 | */ |
1325 | if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { |
1326 | /* XXX stat */ |
1327 | goto drop; |
1328 | } |
1329 | |
1330 | /* |
1331 | * Make sure destination address is not multicast. |
1332 | * Source address checked in ip6_input(). |
1333 | */ |
1334 | if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) { |
1335 | /* XXX stat */ |
1336 | goto drop; |
1337 | } |
1338 | |
1339 | /* We do the checksum after PCB lookup... */ |
1340 | len = m->m_pkthdr.len; |
1341 | tlen = len - toff; |
1342 | iptos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; |
1343 | break; |
1344 | #endif |
1345 | default: |
1346 | m_freem(m); |
1347 | return; |
1348 | } |
1349 | /* |
1350 | * Enforce alignment requirements that are violated in |
1351 | * some cases, see kern/50766 for details. |
1352 | */ |
1353 | if (TCP_HDR_ALIGNED_P(th) == 0) { |
1354 | m = m_copyup(m, toff + sizeof(struct tcphdr), 0); |
1355 | if (m == NULL) { |
1356 | TCP_STATINC(TCP_STAT_RCVSHORT); |
1357 | return; |
1358 | } |
1359 | ip = mtod(m, struct ip *); |
1360 | #ifdef INET6 |
1361 | ip6 = mtod(m, struct ip6_hdr *); |
1362 | #endif |
1363 | th = (struct tcphdr *)(mtod(m, char *) + toff); |
1364 | } |
1365 | KASSERT(TCP_HDR_ALIGNED_P(th)); |
1366 | |
1367 | /* |
1368 | * Check that TCP offset makes sense, |
1369 | * pull out TCP options and adjust length. XXX |
1370 | */ |
1371 | off = th->th_off << 2; |
1372 | if (off < sizeof (struct tcphdr) || off > tlen) { |
1373 | TCP_STATINC(TCP_STAT_RCVBADOFF); |
1374 | goto drop; |
1375 | } |
1376 | tlen -= off; |
1377 | |
1378 | /* |
1379 | * tcp_input() has been modified to use tlen to mean the TCP data |
1380 | * length throughout the function. Other functions can use |
1381 | * m->m_pkthdr.len as the basis for calculating the TCP data length. |
1382 | * rja |
1383 | */ |
1384 | |
1385 | if (off > sizeof (struct tcphdr)) { |
1386 | IP6_EXTHDR_GET(th, struct tcphdr *, m, toff, off); |
1387 | if (th == NULL) { |
1388 | TCP_STATINC(TCP_STAT_RCVSHORT); |
1389 | return; |
1390 | } |
1391 | /* |
1392 | * NOTE: ip/ip6 will not be affected by m_pulldown() |
1393 | * (as they're before toff) and we don't need to update those. |
1394 | */ |
1395 | KASSERT(TCP_HDR_ALIGNED_P(th)); |
1396 | optlen = off - sizeof (struct tcphdr); |
1397 | optp = ((u_int8_t *)th) + sizeof(struct tcphdr); |
1398 | /* |
1399 | * Do quick retrieval of timestamp options ("options |
1400 | * prediction?"). If timestamp is the only option and it's |
1401 | * formatted as recommended in RFC 1323 appendix A, we |
1402 | * quickly get the values now and not bother calling |
1403 | * tcp_dooptions(), etc. |
1404 | */ |
1405 | if ((optlen == TCPOLEN_TSTAMP_APPA || |
1406 | (optlen > TCPOLEN_TSTAMP_APPA && |
1407 | optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) && |
1408 | *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) && |
1409 | (th->th_flags & TH_SYN) == 0) { |
1410 | opti.ts_present = 1; |
1411 | opti.ts_val = ntohl(*(u_int32_t *)(optp + 4)); |
1412 | opti.ts_ecr = ntohl(*(u_int32_t *)(optp + 8)); |
1413 | optp = NULL; /* we've parsed the options */ |
1414 | } |
1415 | } |
1416 | tiflags = th->th_flags; |
1417 | |
1418 | /* |
1419 | * Checksum extended TCP header and data |
1420 | */ |
1421 | if (tcp_input_checksum(af, m, th, toff, off, tlen)) |
1422 | goto badcsum; |
1423 | |
1424 | /* |
1425 | * Locate pcb for segment. |
1426 | */ |
1427 | findpcb: |
1428 | inp = NULL; |
1429 | #ifdef INET6 |
1430 | in6p = NULL; |
1431 | #endif |
1432 | switch (af) { |
1433 | #ifdef INET |
1434 | case AF_INET: |
1435 | inp = in_pcblookup_connect(&tcbtable, ip->ip_src, th->th_sport, |
1436 | ip->ip_dst, th->th_dport, |
1437 | &vestige); |
1438 | if (inp == 0 && !vestige.valid) { |
1439 | TCP_STATINC(TCP_STAT_PCBHASHMISS); |
1440 | inp = in_pcblookup_bind(&tcbtable, ip->ip_dst, th->th_dport); |
1441 | } |
1442 | #ifdef INET6 |
1443 | if (inp == 0 && !vestige.valid) { |
1444 | struct in6_addr s, d; |
1445 | |
1446 | /* mapped addr case */ |
1447 | in6_in_2_v4mapin6(&ip->ip_src, &s); |
1448 | in6_in_2_v4mapin6(&ip->ip_dst, &d); |
1449 | in6p = in6_pcblookup_connect(&tcbtable, &s, |
1450 | th->th_sport, &d, th->th_dport, |
1451 | 0, &vestige); |
1452 | if (in6p == 0 && !vestige.valid) { |
1453 | TCP_STATINC(TCP_STAT_PCBHASHMISS); |
1454 | in6p = in6_pcblookup_bind(&tcbtable, &d, |
1455 | th->th_dport, 0); |
1456 | } |
1457 | } |
1458 | #endif |
1459 | #ifndef INET6 |
1460 | if (inp == 0 && !vestige.valid) |
1461 | #else |
1462 | if (inp == 0 && in6p == 0 && !vestige.valid) |
1463 | #endif |
1464 | { |
1465 | TCP_STATINC(TCP_STAT_NOPORT); |
1466 | if (tcp_log_refused && |
1467 | (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { |
1468 | tcp4_log_refused(ip, th); |
1469 | } |
1470 | tcp_fields_to_host(th); |
1471 | goto dropwithreset_ratelim; |
1472 | } |
1473 | #if defined(IPSEC) |
1474 | if (ipsec_used) { |
1475 | if (inp && |
1476 | (inp->inp_socket->so_options & SO_ACCEPTCONN) == 0 |
1477 | && ipsec4_in_reject(m, inp)) { |
1478 | IPSEC_STATINC(IPSEC_STAT_IN_POLVIO); |
1479 | goto drop; |
1480 | } |
1481 | #ifdef INET6 |
1482 | else if (in6p && |
1483 | (in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 |
1484 | && ipsec6_in_reject_so(m, in6p->in6p_socket)) { |
1485 | IPSEC_STATINC(IPSEC_STAT_IN_POLVIO); |
1486 | goto drop; |
1487 | } |
1488 | #endif |
1489 | } |
1490 | #endif /*IPSEC*/ |
1491 | break; |
1492 | #endif /*INET*/ |
1493 | #ifdef INET6 |
1494 | case AF_INET6: |
1495 | { |
1496 | int faith; |
1497 | |
1498 | #if defined(NFAITH) && NFAITH > 0 |
1499 | faith = faithprefix(&ip6->ip6_dst); |
1500 | #else |
1501 | faith = 0; |
1502 | #endif |
1503 | in6p = in6_pcblookup_connect(&tcbtable, &ip6->ip6_src, |
1504 | th->th_sport, &ip6->ip6_dst, th->th_dport, faith, &vestige); |
1505 | if (!in6p && !vestige.valid) { |
1506 | TCP_STATINC(TCP_STAT_PCBHASHMISS); |
1507 | in6p = in6_pcblookup_bind(&tcbtable, &ip6->ip6_dst, |
1508 | th->th_dport, faith); |
1509 | } |
1510 | if (!in6p && !vestige.valid) { |
1511 | TCP_STATINC(TCP_STAT_NOPORT); |
1512 | if (tcp_log_refused && |
1513 | (tiflags & (TH_RST|TH_ACK|TH_SYN)) == TH_SYN) { |
1514 | tcp6_log_refused(ip6, th); |
1515 | } |
1516 | tcp_fields_to_host(th); |
1517 | goto dropwithreset_ratelim; |
1518 | } |
1519 | #if defined(IPSEC) |
1520 | if (ipsec_used && in6p |
1521 | && (in6p->in6p_socket->so_options & SO_ACCEPTCONN) == 0 |
1522 | && ipsec6_in_reject(m, in6p)) { |
1523 | IPSEC6_STATINC(IPSEC_STAT_IN_POLVIO); |
1524 | goto drop; |
1525 | } |
1526 | #endif /*IPSEC*/ |
1527 | break; |
1528 | } |
1529 | #endif |
1530 | } |
1531 | |
1532 | /* |
1533 | * If the state is CLOSED (i.e., TCB does not exist) then |
1534 | * all data in the incoming segment is discarded. |
1535 | * If the TCB exists but is in CLOSED state, it is embryonic, |
1536 | * but should either do a listen or a connect soon. |
1537 | */ |
1538 | tp = NULL; |
1539 | so = NULL; |
1540 | if (inp) { |
1541 | /* Check the minimum TTL for socket. */ |
1542 | if (ip->ip_ttl < inp->inp_ip_minttl) |
1543 | goto drop; |
1544 | |
1545 | tp = intotcpcb(inp); |
1546 | so = inp->inp_socket; |
1547 | } |
1548 | #ifdef INET6 |
1549 | else if (in6p) { |
1550 | tp = in6totcpcb(in6p); |
1551 | so = in6p->in6p_socket; |
1552 | } |
1553 | #endif |
1554 | else if (vestige.valid) { |
1555 | int mc = 0; |
1556 | |
1557 | /* We do not support the resurrection of vtw tcpcps. |
1558 | */ |
1559 | if (tcp_input_checksum(af, m, th, toff, off, tlen)) |
1560 | goto badcsum; |
1561 | |
1562 | switch (af) { |
1563 | #ifdef INET6 |
1564 | case AF_INET6: |
1565 | mc = IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst); |
1566 | break; |
1567 | #endif |
1568 | |
1569 | case AF_INET: |
1570 | mc = (IN_MULTICAST(ip->ip_dst.s_addr) |
1571 | || in_broadcast(ip->ip_dst, |
1572 | m_get_rcvif_NOMPSAFE(m))); |
1573 | break; |
1574 | } |
1575 | |
1576 | tcp_fields_to_host(th); |
1577 | tcp_vtw_input(th, &vestige, m, tlen, mc); |
1578 | m = 0; |
1579 | goto drop; |
1580 | } |
1581 | |
1582 | if (tp == 0) { |
1583 | tcp_fields_to_host(th); |
1584 | goto dropwithreset_ratelim; |
1585 | } |
1586 | if (tp->t_state == TCPS_CLOSED) |
1587 | goto drop; |
1588 | |
1589 | KASSERT(so->so_lock == softnet_lock); |
1590 | KASSERT(solocked(so)); |
1591 | |
1592 | tcp_fields_to_host(th); |
1593 | |
1594 | /* Unscale the window into a 32-bit value. */ |
1595 | if ((tiflags & TH_SYN) == 0) |
1596 | tiwin = th->th_win << tp->snd_scale; |
1597 | else |
1598 | tiwin = th->th_win; |
1599 | |
1600 | #ifdef INET6 |
1601 | /* save packet options if user wanted */ |
1602 | if (in6p && (in6p->in6p_flags & IN6P_CONTROLOPTS)) { |
1603 | if (in6p->in6p_options) { |
1604 | m_freem(in6p->in6p_options); |
1605 | in6p->in6p_options = 0; |
1606 | } |
1607 | KASSERT(ip6 != NULL); |
1608 | ip6_savecontrol(in6p, &in6p->in6p_options, ip6, m); |
1609 | } |
1610 | #endif |
1611 | |
1612 | if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) { |
1613 | union syn_cache_sa src; |
1614 | union syn_cache_sa dst; |
1615 | |
1616 | memset(&src, 0, sizeof(src)); |
1617 | memset(&dst, 0, sizeof(dst)); |
1618 | switch (af) { |
1619 | #ifdef INET |
1620 | case AF_INET: |
1621 | src.sin.sin_len = sizeof(struct sockaddr_in); |
1622 | src.sin.sin_family = AF_INET; |
1623 | src.sin.sin_addr = ip->ip_src; |
1624 | src.sin.sin_port = th->th_sport; |
1625 | |
1626 | dst.sin.sin_len = sizeof(struct sockaddr_in); |
1627 | dst.sin.sin_family = AF_INET; |
1628 | dst.sin.sin_addr = ip->ip_dst; |
1629 | dst.sin.sin_port = th->th_dport; |
1630 | break; |
1631 | #endif |
1632 | #ifdef INET6 |
1633 | case AF_INET6: |
1634 | src.sin6.sin6_len = sizeof(struct sockaddr_in6); |
1635 | src.sin6.sin6_family = AF_INET6; |
1636 | src.sin6.sin6_addr = ip6->ip6_src; |
1637 | src.sin6.sin6_port = th->th_sport; |
1638 | |
1639 | dst.sin6.sin6_len = sizeof(struct sockaddr_in6); |
1640 | dst.sin6.sin6_family = AF_INET6; |
1641 | dst.sin6.sin6_addr = ip6->ip6_dst; |
1642 | dst.sin6.sin6_port = th->th_dport; |
1643 | break; |
1644 | #endif /* INET6 */ |
1645 | default: |
1646 | goto badsyn; /*sanity*/ |
1647 | } |
1648 | |
1649 | if (so->so_options & SO_DEBUG) { |
1650 | #ifdef TCP_DEBUG |
1651 | ostate = tp->t_state; |
1652 | #endif |
1653 | |
1654 | tcp_saveti = NULL; |
1655 | if (iphlen + sizeof(struct tcphdr) > MHLEN) |
1656 | goto nosave; |
1657 | |
1658 | if (m->m_len > iphlen && (m->m_flags & M_EXT) == 0) { |
1659 | tcp_saveti = m_copym(m, 0, iphlen, M_DONTWAIT); |
1660 | if (!tcp_saveti) |
1661 | goto nosave; |
1662 | } else { |
1663 | MGETHDR(tcp_saveti, M_DONTWAIT, MT_HEADER); |
1664 | if (!tcp_saveti) |
1665 | goto nosave; |
1666 | MCLAIM(m, &tcp_mowner); |
1667 | tcp_saveti->m_len = iphlen; |
1668 | m_copydata(m, 0, iphlen, |
1669 | mtod(tcp_saveti, void *)); |
1670 | } |
1671 | |
1672 | if (M_TRAILINGSPACE(tcp_saveti) < sizeof(struct tcphdr)) { |
1673 | m_freem(tcp_saveti); |
1674 | tcp_saveti = NULL; |
1675 | } else { |
1676 | tcp_saveti->m_len += sizeof(struct tcphdr); |
1677 | memcpy(mtod(tcp_saveti, char *) + iphlen, th, |
1678 | sizeof(struct tcphdr)); |
1679 | } |
1680 | nosave:; |
1681 | } |
1682 | if (so->so_options & SO_ACCEPTCONN) { |
1683 | if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) { |
1684 | if (tiflags & TH_RST) { |
1685 | syn_cache_reset(&src.sa, &dst.sa, th); |
1686 | } else if ((tiflags & (TH_ACK|TH_SYN)) == |
1687 | (TH_ACK|TH_SYN)) { |
1688 | /* |
1689 | * Received a SYN,ACK. This should |
1690 | * never happen while we are in |
1691 | * LISTEN. Send an RST. |
1692 | */ |
1693 | goto badsyn; |
1694 | } else if (tiflags & TH_ACK) { |
1695 | so = syn_cache_get(&src.sa, &dst.sa, |
1696 | th, toff, tlen, so, m); |
1697 | if (so == NULL) { |
1698 | /* |
1699 | * We don't have a SYN for |
1700 | * this ACK; send an RST. |
1701 | */ |
1702 | goto badsyn; |
1703 | } else if (so == |
1704 | (struct socket *)(-1)) { |
1705 | /* |
1706 | * We were unable to create |
1707 | * the connection. If the |
1708 | * 3-way handshake was |
1709 | * completed, and RST has |
1710 | * been sent to the peer. |
1711 | * Since the mbuf might be |
1712 | * in use for the reply, |
1713 | * do not free it. |
1714 | */ |
1715 | m = NULL; |
1716 | } else { |
1717 | /* |
1718 | * We have created a |
1719 | * full-blown connection. |
1720 | */ |
1721 | tp = NULL; |
1722 | inp = NULL; |
1723 | #ifdef INET6 |
1724 | in6p = NULL; |
1725 | #endif |
1726 | switch (so->so_proto->pr_domain->dom_family) { |
1727 | #ifdef INET |
1728 | case AF_INET: |
1729 | inp = sotoinpcb(so); |
1730 | tp = intotcpcb(inp); |
1731 | break; |
1732 | #endif |
1733 | #ifdef INET6 |
1734 | case AF_INET6: |
1735 | in6p = sotoin6pcb(so); |
1736 | tp = in6totcpcb(in6p); |
1737 | break; |
1738 | #endif |
1739 | } |
1740 | if (tp == NULL) |
1741 | goto badsyn; /*XXX*/ |
1742 | tiwin <<= tp->snd_scale; |
1743 | goto after_listen; |
1744 | } |
1745 | } else { |
1746 | /* |
1747 | * None of RST, SYN or ACK was set. |
1748 | * This is an invalid packet for a |
1749 | * TCB in LISTEN state. Send a RST. |
1750 | */ |
1751 | goto badsyn; |
1752 | } |
1753 | } else { |
1754 | /* |
1755 | * Received a SYN. |
1756 | * |
1757 | * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN |
1758 | */ |
1759 | if (m->m_flags & (M_BCAST|M_MCAST)) |
1760 | goto drop; |
1761 | |
1762 | switch (af) { |
1763 | #ifdef INET6 |
1764 | case AF_INET6: |
1765 | if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) |
1766 | goto drop; |
1767 | break; |
1768 | #endif /* INET6 */ |
1769 | case AF_INET: |
1770 | if (IN_MULTICAST(ip->ip_dst.s_addr) || |
1771 | in_broadcast(ip->ip_dst, |
1772 | m_get_rcvif_NOMPSAFE(m))) |
1773 | goto drop; |
1774 | break; |
1775 | } |
1776 | |
1777 | #ifdef INET6 |
1778 | /* |
1779 | * If deprecated address is forbidden, we do |
1780 | * not accept SYN to deprecated interface |
1781 | * address to prevent any new inbound |
1782 | * connection from getting established. |
1783 | * When we do not accept SYN, we send a TCP |
1784 | * RST, with deprecated source address (instead |
1785 | * of dropping it). We compromise it as it is |
1786 | * much better for peer to send a RST, and |
1787 | * RST will be the final packet for the |
1788 | * exchange. |
1789 | * |
1790 | * If we do not forbid deprecated addresses, we |
1791 | * accept the SYN packet. RFC2462 does not |
1792 | * suggest dropping SYN in this case. |
1793 | * If we decipher RFC2462 5.5.4, it says like |
1794 | * this: |
1795 | * 1. use of deprecated addr with existing |
1796 | * communication is okay - "SHOULD continue |
1797 | * to be used" |
1798 | * 2. use of it with new communication: |
1799 | * (2a) "SHOULD NOT be used if alternate |
1800 | * address with sufficient scope is |
1801 | * available" |
1802 | * (2b) nothing mentioned otherwise. |
1803 | * Here we fall into (2b) case as we have no |
1804 | * choice in our source address selection - we |
1805 | * must obey the peer. |
1806 | * |
1807 | * The wording in RFC2462 is confusing, and |
1808 | * there are multiple description text for |
1809 | * deprecated address handling - worse, they |
1810 | * are not exactly the same. I believe 5.5.4 |
1811 | * is the best one, so we follow 5.5.4. |
1812 | */ |
1813 | if (af == AF_INET6 && !ip6_use_deprecated) { |
1814 | struct in6_ifaddr *ia6; |
1815 | int s; |
1816 | struct ifnet *rcvif = m_get_rcvif(m, &s); |
1817 | if (rcvif == NULL) |
1818 | goto dropwithreset; /* XXX */ |
1819 | if ((ia6 = in6ifa_ifpwithaddr(rcvif, |
1820 | &ip6->ip6_dst)) && |
1821 | (ia6->ia6_flags & IN6_IFF_DEPRECATED)) { |
1822 | tp = NULL; |
1823 | m_put_rcvif(rcvif, &s); |
1824 | goto dropwithreset; |
1825 | } |
1826 | m_put_rcvif(rcvif, &s); |
1827 | } |
1828 | #endif |
1829 | |
1830 | #if defined(IPSEC) |
1831 | if (ipsec_used) { |
1832 | switch (af) { |
1833 | #ifdef INET |
1834 | case AF_INET: |
1835 | if (!ipsec4_in_reject_so(m, so)) |
1836 | break; |
1837 | IPSEC_STATINC( |
1838 | IPSEC_STAT_IN_POLVIO); |
1839 | tp = NULL; |
1840 | goto dropwithreset; |
1841 | #endif |
1842 | #ifdef INET6 |
1843 | case AF_INET6: |
1844 | if (!ipsec6_in_reject_so(m, so)) |
1845 | break; |
1846 | IPSEC6_STATINC( |
1847 | IPSEC_STAT_IN_POLVIO); |
1848 | tp = NULL; |
1849 | goto dropwithreset; |
1850 | #endif /*INET6*/ |
1851 | } |
1852 | } |
1853 | #endif /*IPSEC*/ |
1854 | |
1855 | /* |
1856 | * LISTEN socket received a SYN |
1857 | * from itself? This can't possibly |
1858 | * be valid; drop the packet. |
1859 | */ |
1860 | if (th->th_sport == th->th_dport) { |
1861 | int i; |
1862 | |
1863 | switch (af) { |
1864 | #ifdef INET |
1865 | case AF_INET: |
1866 | i = in_hosteq(ip->ip_src, ip->ip_dst); |
1867 | break; |
1868 | #endif |
1869 | #ifdef INET6 |
1870 | case AF_INET6: |
1871 | i = IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &ip6->ip6_dst); |
1872 | break; |
1873 | #endif |
1874 | default: |
1875 | i = 1; |
1876 | } |
1877 | if (i) { |
1878 | TCP_STATINC(TCP_STAT_BADSYN); |
1879 | goto drop; |
1880 | } |
1881 | } |
1882 | |
1883 | /* |
1884 | * SYN looks ok; create compressed TCP |
1885 | * state for it. |
1886 | */ |
1887 | if (so->so_qlen <= so->so_qlimit && |
1888 | syn_cache_add(&src.sa, &dst.sa, th, tlen, |
1889 | so, m, optp, optlen, &opti)) |
1890 | m = NULL; |
1891 | } |
1892 | goto drop; |
1893 | } |
1894 | } |
1895 | |
1896 | after_listen: |
1897 | #ifdef DIAGNOSTIC |
1898 | /* |
1899 | * Should not happen now that all embryonic connections |
1900 | * are handled with compressed state. |
1901 | */ |
1902 | if (tp->t_state == TCPS_LISTEN) |
1903 | panic("tcp_input: TCPS_LISTEN" ); |
1904 | #endif |
1905 | |
1906 | /* |
1907 | * Segment received on connection. |
1908 | * Reset idle time and keep-alive timer. |
1909 | */ |
1910 | tp->t_rcvtime = tcp_now; |
1911 | if (TCPS_HAVEESTABLISHED(tp->t_state)) |
1912 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepidle); |
1913 | |
1914 | /* |
1915 | * Process options. |
1916 | */ |
1917 | #ifdef TCP_SIGNATURE |
1918 | if (optp || (tp->t_flags & TF_SIGNATURE)) |
1919 | #else |
1920 | if (optp) |
1921 | #endif |
1922 | if (tcp_dooptions(tp, optp, optlen, th, m, toff, &opti) < 0) |
1923 | goto drop; |
1924 | |
1925 | if (TCP_SACK_ENABLED(tp)) { |
1926 | tcp_del_sackholes(tp, th); |
1927 | } |
1928 | |
1929 | if (TCP_ECN_ALLOWED(tp)) { |
1930 | if (tiflags & TH_CWR) { |
1931 | tp->t_flags &= ~TF_ECN_SND_ECE; |
1932 | } |
1933 | switch (iptos & IPTOS_ECN_MASK) { |
1934 | case IPTOS_ECN_CE: |
1935 | tp->t_flags |= TF_ECN_SND_ECE; |
1936 | TCP_STATINC(TCP_STAT_ECN_CE); |
1937 | break; |
1938 | case IPTOS_ECN_ECT0: |
1939 | TCP_STATINC(TCP_STAT_ECN_ECT); |
1940 | break; |
1941 | case IPTOS_ECN_ECT1: |
1942 | /* XXX: ignore for now -- rpaulo */ |
1943 | break; |
1944 | } |
1945 | /* |
1946 | * Congestion experienced. |
1947 | * Ignore if we are already trying to recover. |
1948 | */ |
1949 | if ((tiflags & TH_ECE) && SEQ_GEQ(tp->snd_una, tp->snd_recover)) |
1950 | tp->t_congctl->cong_exp(tp); |
1951 | } |
1952 | |
1953 | if (opti.ts_present && opti.ts_ecr) { |
1954 | /* |
1955 | * Calculate the RTT from the returned time stamp and the |
1956 | * connection's time base. If the time stamp is later than |
1957 | * the current time, or is extremely old, fall back to non-1323 |
1958 | * RTT calculation. Since ts_rtt is unsigned, we can test both |
1959 | * at the same time. |
1960 | * |
1961 | * Note that ts_rtt is in units of slow ticks (500 |
1962 | * ms). Since most earthbound RTTs are < 500 ms, |
1963 | * observed values will have large quantization noise. |
1964 | * Our smoothed RTT is then the fraction of observed |
1965 | * samples that are 1 tick instead of 0 (times 500 |
1966 | * ms). |
1967 | * |
1968 | * ts_rtt is increased by 1 to denote a valid sample, |
1969 | * with 0 indicating an invalid measurement. This |
1970 | * extra 1 must be removed when ts_rtt is used, or |
1971 | * else an an erroneous extra 500 ms will result. |
1972 | */ |
1973 | ts_rtt = TCP_TIMESTAMP(tp) - opti.ts_ecr + 1; |
1974 | if (ts_rtt > TCP_PAWS_IDLE) |
1975 | ts_rtt = 0; |
1976 | } else { |
1977 | ts_rtt = 0; |
1978 | } |
1979 | |
1980 | /* |
1981 | * Header prediction: check for the two common cases |
1982 | * of a uni-directional data xfer. If the packet has |
1983 | * no control flags, is in-sequence, the window didn't |
1984 | * change and we're not retransmitting, it's a |
1985 | * candidate. If the length is zero and the ack moved |
1986 | * forward, we're the sender side of the xfer. Just |
1987 | * free the data acked & wake any higher level process |
1988 | * that was blocked waiting for space. If the length |
1989 | * is non-zero and the ack didn't move, we're the |
1990 | * receiver side. If we're getting packets in-order |
1991 | * (the reassembly queue is empty), add the data to |
1992 | * the socket buffer and note that we need a delayed ack. |
1993 | */ |
1994 | if (tp->t_state == TCPS_ESTABLISHED && |
1995 | (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ECE|TH_CWR|TH_ACK)) |
1996 | == TH_ACK && |
1997 | (!opti.ts_present || TSTMP_GEQ(opti.ts_val, tp->ts_recent)) && |
1998 | th->th_seq == tp->rcv_nxt && |
1999 | tiwin && tiwin == tp->snd_wnd && |
2000 | tp->snd_nxt == tp->snd_max) { |
2001 | |
2002 | /* |
2003 | * If last ACK falls within this segment's sequence numbers, |
2004 | * record the timestamp. |
2005 | * NOTE that the test is modified according to the latest |
2006 | * proposal of the tcplw@cray.com list (Braden 1993/04/26). |
2007 | * |
2008 | * note that we already know |
2009 | * TSTMP_GEQ(opti.ts_val, tp->ts_recent) |
2010 | */ |
2011 | if (opti.ts_present && |
2012 | SEQ_LEQ(th->th_seq, tp->last_ack_sent)) { |
2013 | tp->ts_recent_age = tcp_now; |
2014 | tp->ts_recent = opti.ts_val; |
2015 | } |
2016 | |
2017 | if (tlen == 0) { |
2018 | /* Ack prediction. */ |
2019 | if (SEQ_GT(th->th_ack, tp->snd_una) && |
2020 | SEQ_LEQ(th->th_ack, tp->snd_max) && |
2021 | tp->snd_cwnd >= tp->snd_wnd && |
2022 | tp->t_partialacks < 0) { |
2023 | /* |
2024 | * this is a pure ack for outstanding data. |
2025 | */ |
2026 | if (ts_rtt) |
2027 | tcp_xmit_timer(tp, ts_rtt - 1); |
2028 | else if (tp->t_rtttime && |
2029 | SEQ_GT(th->th_ack, tp->t_rtseq)) |
2030 | tcp_xmit_timer(tp, |
2031 | tcp_now - tp->t_rtttime); |
2032 | acked = th->th_ack - tp->snd_una; |
2033 | tcps = TCP_STAT_GETREF(); |
2034 | tcps[TCP_STAT_PREDACK]++; |
2035 | tcps[TCP_STAT_RCVACKPACK]++; |
2036 | tcps[TCP_STAT_RCVACKBYTE] += acked; |
2037 | TCP_STAT_PUTREF(); |
2038 | nd6_hint(tp); |
2039 | |
2040 | if (acked > (tp->t_lastoff - tp->t_inoff)) |
2041 | tp->t_lastm = NULL; |
2042 | sbdrop(&so->so_snd, acked); |
2043 | tp->t_lastoff -= acked; |
2044 | |
2045 | icmp_check(tp, th, acked); |
2046 | |
2047 | tp->snd_una = th->th_ack; |
2048 | tp->snd_fack = tp->snd_una; |
2049 | if (SEQ_LT(tp->snd_high, tp->snd_una)) |
2050 | tp->snd_high = tp->snd_una; |
2051 | m_freem(m); |
2052 | |
2053 | /* |
2054 | * If all outstanding data are acked, stop |
2055 | * retransmit timer, otherwise restart timer |
2056 | * using current (possibly backed-off) value. |
2057 | * If process is waiting for space, |
2058 | * wakeup/selnotify/signal. If data |
2059 | * are ready to send, let tcp_output |
2060 | * decide between more output or persist. |
2061 | */ |
2062 | if (tp->snd_una == tp->snd_max) |
2063 | TCP_TIMER_DISARM(tp, TCPT_REXMT); |
2064 | else if (TCP_TIMER_ISARMED(tp, |
2065 | TCPT_PERSIST) == 0) |
2066 | TCP_TIMER_ARM(tp, TCPT_REXMT, |
2067 | tp->t_rxtcur); |
2068 | |
2069 | sowwakeup(so); |
2070 | if (so->so_snd.sb_cc) { |
2071 | KERNEL_LOCK(1, NULL); |
2072 | (void) tcp_output(tp); |
2073 | KERNEL_UNLOCK_ONE(NULL); |
2074 | } |
2075 | if (tcp_saveti) |
2076 | m_freem(tcp_saveti); |
2077 | return; |
2078 | } |
2079 | } else if (th->th_ack == tp->snd_una && |
2080 | TAILQ_FIRST(&tp->segq) == NULL && |
2081 | tlen <= sbspace(&so->so_rcv)) { |
2082 | int newsize = 0; /* automatic sockbuf scaling */ |
2083 | |
2084 | /* |
2085 | * this is a pure, in-sequence data packet |
2086 | * with nothing on the reassembly queue and |
2087 | * we have enough buffer space to take it. |
2088 | */ |
2089 | tp->rcv_nxt += tlen; |
2090 | tcps = TCP_STAT_GETREF(); |
2091 | tcps[TCP_STAT_PREDDAT]++; |
2092 | tcps[TCP_STAT_RCVPACK]++; |
2093 | tcps[TCP_STAT_RCVBYTE] += tlen; |
2094 | TCP_STAT_PUTREF(); |
2095 | nd6_hint(tp); |
2096 | |
2097 | /* |
2098 | * Automatic sizing enables the performance of large buffers |
2099 | * and most of the efficiency of small ones by only allocating |
2100 | * space when it is needed. |
2101 | * |
2102 | * On the receive side the socket buffer memory is only rarely |
2103 | * used to any significant extent. This allows us to be much |
2104 | * more aggressive in scaling the receive socket buffer. For |
2105 | * the case that the buffer space is actually used to a large |
2106 | * extent and we run out of kernel memory we can simply drop |
2107 | * the new segments; TCP on the sender will just retransmit it |
2108 | * later. Setting the buffer size too big may only consume too |
2109 | * much kernel memory if the application doesn't read() from |
2110 | * the socket or packet loss or reordering makes use of the |
2111 | * reassembly queue. |
2112 | * |
2113 | * The criteria to step up the receive buffer one notch are: |
2114 | * 1. the number of bytes received during the time it takes |
2115 | * one timestamp to be reflected back to us (the RTT); |
2116 | * 2. received bytes per RTT is within seven eighth of the |
2117 | * current socket buffer size; |
2118 | * 3. receive buffer size has not hit maximal automatic size; |
2119 | * |
2120 | * This algorithm does one step per RTT at most and only if |
2121 | * we receive a bulk stream w/o packet losses or reorderings. |
2122 | * Shrinking the buffer during idle times is not necessary as |
2123 | * it doesn't consume any memory when idle. |
2124 | * |
2125 | * TODO: Only step up if the application is actually serving |
2126 | * the buffer to better manage the socket buffer resources. |
2127 | */ |
2128 | if (tcp_do_autorcvbuf && |
2129 | opti.ts_ecr && |
2130 | (so->so_rcv.sb_flags & SB_AUTOSIZE)) { |
2131 | if (opti.ts_ecr > tp->rfbuf_ts && |
2132 | opti.ts_ecr - tp->rfbuf_ts < PR_SLOWHZ) { |
2133 | if (tp->rfbuf_cnt > |
2134 | (so->so_rcv.sb_hiwat / 8 * 7) && |
2135 | so->so_rcv.sb_hiwat < |
2136 | tcp_autorcvbuf_max) { |
2137 | newsize = |
2138 | min(so->so_rcv.sb_hiwat + |
2139 | tcp_autorcvbuf_inc, |
2140 | tcp_autorcvbuf_max); |
2141 | } |
2142 | /* Start over with next RTT. */ |
2143 | tp->rfbuf_ts = 0; |
2144 | tp->rfbuf_cnt = 0; |
2145 | } else |
2146 | tp->rfbuf_cnt += tlen; /* add up */ |
2147 | } |
2148 | |
2149 | /* |
2150 | * Drop TCP, IP headers and TCP options then add data |
2151 | * to socket buffer. |
2152 | */ |
2153 | if (so->so_state & SS_CANTRCVMORE) |
2154 | m_freem(m); |
2155 | else { |
2156 | /* |
2157 | * Set new socket buffer size. |
2158 | * Give up when limit is reached. |
2159 | */ |
2160 | if (newsize) |
2161 | if (!sbreserve(&so->so_rcv, |
2162 | newsize, so)) |
2163 | so->so_rcv.sb_flags &= ~SB_AUTOSIZE; |
2164 | m_adj(m, toff + off); |
2165 | sbappendstream(&so->so_rcv, m); |
2166 | } |
2167 | sorwakeup(so); |
2168 | tcp_setup_ack(tp, th); |
2169 | if (tp->t_flags & TF_ACKNOW) { |
2170 | KERNEL_LOCK(1, NULL); |
2171 | (void) tcp_output(tp); |
2172 | KERNEL_UNLOCK_ONE(NULL); |
2173 | } |
2174 | if (tcp_saveti) |
2175 | m_freem(tcp_saveti); |
2176 | return; |
2177 | } |
2178 | } |
2179 | |
2180 | /* |
2181 | * Compute mbuf offset to TCP data segment. |
2182 | */ |
2183 | hdroptlen = toff + off; |
2184 | |
2185 | /* |
2186 | * Calculate amount of space in receive window, |
2187 | * and then do TCP input processing. |
2188 | * Receive window is amount of space in rcv queue, |
2189 | * but not less than advertised window. |
2190 | */ |
2191 | { int win; |
2192 | |
2193 | win = sbspace(&so->so_rcv); |
2194 | if (win < 0) |
2195 | win = 0; |
2196 | tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt)); |
2197 | } |
2198 | |
2199 | /* Reset receive buffer auto scaling when not in bulk receive mode. */ |
2200 | tp->rfbuf_ts = 0; |
2201 | tp->rfbuf_cnt = 0; |
2202 | |
2203 | switch (tp->t_state) { |
2204 | /* |
2205 | * If the state is SYN_SENT: |
2206 | * if seg contains an ACK, but not for our SYN, drop the input. |
2207 | * if seg contains a RST, then drop the connection. |
2208 | * if seg does not contain SYN, then drop it. |
2209 | * Otherwise this is an acceptable SYN segment |
2210 | * initialize tp->rcv_nxt and tp->irs |
2211 | * if seg contains ack then advance tp->snd_una |
2212 | * if seg contains a ECE and ECN support is enabled, the stream |
2213 | * is ECN capable. |
2214 | * if SYN has been acked change to ESTABLISHED else SYN_RCVD state |
2215 | * arrange for segment to be acked (eventually) |
2216 | * continue processing rest of data/controls, beginning with URG |
2217 | */ |
2218 | case TCPS_SYN_SENT: |
2219 | if ((tiflags & TH_ACK) && |
2220 | (SEQ_LEQ(th->th_ack, tp->iss) || |
2221 | SEQ_GT(th->th_ack, tp->snd_max))) |
2222 | goto dropwithreset; |
2223 | if (tiflags & TH_RST) { |
2224 | if (tiflags & TH_ACK) |
2225 | tp = tcp_drop(tp, ECONNREFUSED); |
2226 | goto drop; |
2227 | } |
2228 | if ((tiflags & TH_SYN) == 0) |
2229 | goto drop; |
2230 | if (tiflags & TH_ACK) { |
2231 | tp->snd_una = th->th_ack; |
2232 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
2233 | tp->snd_nxt = tp->snd_una; |
2234 | if (SEQ_LT(tp->snd_high, tp->snd_una)) |
2235 | tp->snd_high = tp->snd_una; |
2236 | TCP_TIMER_DISARM(tp, TCPT_REXMT); |
2237 | |
2238 | if ((tiflags & TH_ECE) && tcp_do_ecn) { |
2239 | tp->t_flags |= TF_ECN_PERMIT; |
2240 | TCP_STATINC(TCP_STAT_ECN_SHS); |
2241 | } |
2242 | |
2243 | } |
2244 | tp->irs = th->th_seq; |
2245 | tcp_rcvseqinit(tp); |
2246 | tp->t_flags |= TF_ACKNOW; |
2247 | tcp_mss_from_peer(tp, opti.maxseg); |
2248 | |
2249 | /* |
2250 | * Initialize the initial congestion window. If we |
2251 | * had to retransmit the SYN, we must initialize cwnd |
2252 | * to 1 segment (i.e. the Loss Window). |
2253 | */ |
2254 | if (tp->t_flags & TF_SYN_REXMT) |
2255 | tp->snd_cwnd = tp->t_peermss; |
2256 | else { |
2257 | int ss = tcp_init_win; |
2258 | #ifdef INET |
2259 | if (inp != NULL && in_localaddr(inp->inp_faddr)) |
2260 | ss = tcp_init_win_local; |
2261 | #endif |
2262 | #ifdef INET6 |
2263 | if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) |
2264 | ss = tcp_init_win_local; |
2265 | #endif |
2266 | tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); |
2267 | } |
2268 | |
2269 | tcp_rmx_rtt(tp); |
2270 | if (tiflags & TH_ACK) { |
2271 | TCP_STATINC(TCP_STAT_CONNECTS); |
2272 | /* |
2273 | * move tcp_established before soisconnected |
2274 | * because upcall handler can drive tcp_output |
2275 | * functionality. |
2276 | * XXX we might call soisconnected at the end of |
2277 | * all processing |
2278 | */ |
2279 | tcp_established(tp); |
2280 | soisconnected(so); |
2281 | /* Do window scaling on this connection? */ |
2282 | if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == |
2283 | (TF_RCVD_SCALE|TF_REQ_SCALE)) { |
2284 | tp->snd_scale = tp->requested_s_scale; |
2285 | tp->rcv_scale = tp->request_r_scale; |
2286 | } |
2287 | TCP_REASS_LOCK(tp); |
2288 | (void) tcp_reass(tp, NULL, NULL, &tlen); |
2289 | /* |
2290 | * if we didn't have to retransmit the SYN, |
2291 | * use its rtt as our initial srtt & rtt var. |
2292 | */ |
2293 | if (tp->t_rtttime) |
2294 | tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); |
2295 | } else |
2296 | tp->t_state = TCPS_SYN_RECEIVED; |
2297 | |
2298 | /* |
2299 | * Advance th->th_seq to correspond to first data byte. |
2300 | * If data, trim to stay within window, |
2301 | * dropping FIN if necessary. |
2302 | */ |
2303 | th->th_seq++; |
2304 | if (tlen > tp->rcv_wnd) { |
2305 | todrop = tlen - tp->rcv_wnd; |
2306 | m_adj(m, -todrop); |
2307 | tlen = tp->rcv_wnd; |
2308 | tiflags &= ~TH_FIN; |
2309 | tcps = TCP_STAT_GETREF(); |
2310 | tcps[TCP_STAT_RCVPACKAFTERWIN]++; |
2311 | tcps[TCP_STAT_RCVBYTEAFTERWIN] += todrop; |
2312 | TCP_STAT_PUTREF(); |
2313 | } |
2314 | tp->snd_wl1 = th->th_seq - 1; |
2315 | tp->rcv_up = th->th_seq; |
2316 | goto step6; |
2317 | |
2318 | /* |
2319 | * If the state is SYN_RECEIVED: |
2320 | * If seg contains an ACK, but not for our SYN, drop the input |
2321 | * and generate an RST. See page 36, rfc793 |
2322 | */ |
2323 | case TCPS_SYN_RECEIVED: |
2324 | if ((tiflags & TH_ACK) && |
2325 | (SEQ_LEQ(th->th_ack, tp->iss) || |
2326 | SEQ_GT(th->th_ack, tp->snd_max))) |
2327 | goto dropwithreset; |
2328 | break; |
2329 | } |
2330 | |
2331 | /* |
2332 | * States other than LISTEN or SYN_SENT. |
2333 | * First check timestamp, if present. |
2334 | * Then check that at least some bytes of segment are within |
2335 | * receive window. If segment begins before rcv_nxt, |
2336 | * drop leading data (and SYN); if nothing left, just ack. |
2337 | * |
2338 | * RFC 1323 PAWS: If we have a timestamp reply on this segment |
2339 | * and it's less than ts_recent, drop it. |
2340 | */ |
2341 | if (opti.ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent && |
2342 | TSTMP_LT(opti.ts_val, tp->ts_recent)) { |
2343 | |
2344 | /* Check to see if ts_recent is over 24 days old. */ |
2345 | if (tcp_now - tp->ts_recent_age > TCP_PAWS_IDLE) { |
2346 | /* |
2347 | * Invalidate ts_recent. If this segment updates |
2348 | * ts_recent, the age will be reset later and ts_recent |
2349 | * will get a valid value. If it does not, setting |
2350 | * ts_recent to zero will at least satisfy the |
2351 | * requirement that zero be placed in the timestamp |
2352 | * echo reply when ts_recent isn't valid. The |
2353 | * age isn't reset until we get a valid ts_recent |
2354 | * because we don't want out-of-order segments to be |
2355 | * dropped when ts_recent is old. |
2356 | */ |
2357 | tp->ts_recent = 0; |
2358 | } else { |
2359 | tcps = TCP_STAT_GETREF(); |
2360 | tcps[TCP_STAT_RCVDUPPACK]++; |
2361 | tcps[TCP_STAT_RCVDUPBYTE] += tlen; |
2362 | tcps[TCP_STAT_PAWSDROP]++; |
2363 | TCP_STAT_PUTREF(); |
2364 | tcp_new_dsack(tp, th->th_seq, tlen); |
2365 | goto dropafterack; |
2366 | } |
2367 | } |
2368 | |
2369 | todrop = tp->rcv_nxt - th->th_seq; |
2370 | dupseg = false; |
2371 | if (todrop > 0) { |
2372 | if (tiflags & TH_SYN) { |
2373 | tiflags &= ~TH_SYN; |
2374 | th->th_seq++; |
2375 | if (th->th_urp > 1) |
2376 | th->th_urp--; |
2377 | else { |
2378 | tiflags &= ~TH_URG; |
2379 | th->th_urp = 0; |
2380 | } |
2381 | todrop--; |
2382 | } |
2383 | if (todrop > tlen || |
2384 | (todrop == tlen && (tiflags & TH_FIN) == 0)) { |
2385 | /* |
2386 | * Any valid FIN or RST must be to the left of the |
2387 | * window. At this point the FIN or RST must be a |
2388 | * duplicate or out of sequence; drop it. |
2389 | */ |
2390 | if (tiflags & TH_RST) |
2391 | goto drop; |
2392 | tiflags &= ~(TH_FIN|TH_RST); |
2393 | /* |
2394 | * Send an ACK to resynchronize and drop any data. |
2395 | * But keep on processing for RST or ACK. |
2396 | */ |
2397 | tp->t_flags |= TF_ACKNOW; |
2398 | todrop = tlen; |
2399 | dupseg = true; |
2400 | tcps = TCP_STAT_GETREF(); |
2401 | tcps[TCP_STAT_RCVDUPPACK]++; |
2402 | tcps[TCP_STAT_RCVDUPBYTE] += todrop; |
2403 | TCP_STAT_PUTREF(); |
2404 | } else if ((tiflags & TH_RST) && |
2405 | th->th_seq != tp->rcv_nxt) { |
2406 | /* |
2407 | * Test for reset before adjusting the sequence |
2408 | * number for overlapping data. |
2409 | */ |
2410 | goto dropafterack_ratelim; |
2411 | } else { |
2412 | tcps = TCP_STAT_GETREF(); |
2413 | tcps[TCP_STAT_RCVPARTDUPPACK]++; |
2414 | tcps[TCP_STAT_RCVPARTDUPBYTE] += todrop; |
2415 | TCP_STAT_PUTREF(); |
2416 | } |
2417 | tcp_new_dsack(tp, th->th_seq, todrop); |
2418 | hdroptlen += todrop; /*drop from head afterwards*/ |
2419 | th->th_seq += todrop; |
2420 | tlen -= todrop; |
2421 | if (th->th_urp > todrop) |
2422 | th->th_urp -= todrop; |
2423 | else { |
2424 | tiflags &= ~TH_URG; |
2425 | th->th_urp = 0; |
2426 | } |
2427 | } |
2428 | |
2429 | /* |
2430 | * If new data are received on a connection after the |
2431 | * user processes are gone, then RST the other end. |
2432 | */ |
2433 | if ((so->so_state & SS_NOFDREF) && |
2434 | tp->t_state > TCPS_CLOSE_WAIT && tlen) { |
2435 | tp = tcp_close(tp); |
2436 | TCP_STATINC(TCP_STAT_RCVAFTERCLOSE); |
2437 | goto dropwithreset; |
2438 | } |
2439 | |
2440 | /* |
2441 | * If segment ends after window, drop trailing data |
2442 | * (and PUSH and FIN); if nothing left, just ACK. |
2443 | */ |
2444 | todrop = (th->th_seq + tlen) - (tp->rcv_nxt+tp->rcv_wnd); |
2445 | if (todrop > 0) { |
2446 | TCP_STATINC(TCP_STAT_RCVPACKAFTERWIN); |
2447 | if (todrop >= tlen) { |
2448 | /* |
2449 | * The segment actually starts after the window. |
2450 | * th->th_seq + tlen - tp->rcv_nxt - tp->rcv_wnd >= tlen |
2451 | * th->th_seq - tp->rcv_nxt - tp->rcv_wnd >= 0 |
2452 | * th->th_seq >= tp->rcv_nxt + tp->rcv_wnd |
2453 | */ |
2454 | TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, tlen); |
2455 | /* |
2456 | * If a new connection request is received |
2457 | * while in TIME_WAIT, drop the old connection |
2458 | * and start over if the sequence numbers |
2459 | * are above the previous ones. |
2460 | * |
2461 | * NOTE: We will checksum the packet again, and |
2462 | * so we need to put the header fields back into |
2463 | * network order! |
2464 | * XXX This kind of sucks, but we don't expect |
2465 | * XXX this to happen very often, so maybe it |
2466 | * XXX doesn't matter so much. |
2467 | */ |
2468 | if (tiflags & TH_SYN && |
2469 | tp->t_state == TCPS_TIME_WAIT && |
2470 | SEQ_GT(th->th_seq, tp->rcv_nxt)) { |
2471 | tp = tcp_close(tp); |
2472 | tcp_fields_to_net(th); |
2473 | goto findpcb; |
2474 | } |
2475 | /* |
2476 | * If window is closed can only take segments at |
2477 | * window edge, and have to drop data and PUSH from |
2478 | * incoming segments. Continue processing, but |
2479 | * remember to ack. Otherwise, drop segment |
2480 | * and (if not RST) ack. |
2481 | */ |
2482 | if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) { |
2483 | tp->t_flags |= TF_ACKNOW; |
2484 | TCP_STATINC(TCP_STAT_RCVWINPROBE); |
2485 | } else |
2486 | goto dropafterack; |
2487 | } else |
2488 | TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, todrop); |
2489 | m_adj(m, -todrop); |
2490 | tlen -= todrop; |
2491 | tiflags &= ~(TH_PUSH|TH_FIN); |
2492 | } |
2493 | |
2494 | /* |
2495 | * If last ACK falls within this segment's sequence numbers, |
2496 | * record the timestamp. |
2497 | * NOTE: |
2498 | * 1) That the test incorporates suggestions from the latest |
2499 | * proposal of the tcplw@cray.com list (Braden 1993/04/26). |
2500 | * 2) That updating only on newer timestamps interferes with |
2501 | * our earlier PAWS tests, so this check should be solely |
2502 | * predicated on the sequence space of this segment. |
2503 | * 3) That we modify the segment boundary check to be |
2504 | * Last.ACK.Sent <= SEG.SEQ + SEG.Len |
2505 | * instead of RFC1323's |
2506 | * Last.ACK.Sent < SEG.SEQ + SEG.Len, |
2507 | * This modified check allows us to overcome RFC1323's |
2508 | * limitations as described in Stevens TCP/IP Illustrated |
2509 | * Vol. 2 p.869. In such cases, we can still calculate the |
2510 | * RTT correctly when RCV.NXT == Last.ACK.Sent. |
2511 | */ |
2512 | if (opti.ts_present && |
2513 | SEQ_LEQ(th->th_seq, tp->last_ack_sent) && |
2514 | SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen + |
2515 | ((tiflags & (TH_SYN|TH_FIN)) != 0))) { |
2516 | tp->ts_recent_age = tcp_now; |
2517 | tp->ts_recent = opti.ts_val; |
2518 | } |
2519 | |
2520 | /* |
2521 | * If the RST bit is set examine the state: |
2522 | * SYN_RECEIVED STATE: |
2523 | * If passive open, return to LISTEN state. |
2524 | * If active open, inform user that connection was refused. |
2525 | * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: |
2526 | * Inform user that connection was reset, and close tcb. |
2527 | * CLOSING, LAST_ACK, TIME_WAIT STATES |
2528 | * Close the tcb. |
2529 | */ |
2530 | if (tiflags & TH_RST) { |
2531 | if (th->th_seq != tp->rcv_nxt) |
2532 | goto dropafterack_ratelim; |
2533 | |
2534 | switch (tp->t_state) { |
2535 | case TCPS_SYN_RECEIVED: |
2536 | so->so_error = ECONNREFUSED; |
2537 | goto close; |
2538 | |
2539 | case TCPS_ESTABLISHED: |
2540 | case TCPS_FIN_WAIT_1: |
2541 | case TCPS_FIN_WAIT_2: |
2542 | case TCPS_CLOSE_WAIT: |
2543 | so->so_error = ECONNRESET; |
2544 | close: |
2545 | tp->t_state = TCPS_CLOSED; |
2546 | TCP_STATINC(TCP_STAT_DROPS); |
2547 | tp = tcp_close(tp); |
2548 | goto drop; |
2549 | |
2550 | case TCPS_CLOSING: |
2551 | case TCPS_LAST_ACK: |
2552 | case TCPS_TIME_WAIT: |
2553 | tp = tcp_close(tp); |
2554 | goto drop; |
2555 | } |
2556 | } |
2557 | |
2558 | /* |
2559 | * Since we've covered the SYN-SENT and SYN-RECEIVED states above |
2560 | * we must be in a synchronized state. RFC791 states (under RST |
2561 | * generation) that any unacceptable segment (an out-of-order SYN |
2562 | * qualifies) received in a synchronized state must elicit only an |
2563 | * empty acknowledgment segment ... and the connection remains in |
2564 | * the same state. |
2565 | */ |
2566 | if (tiflags & TH_SYN) { |
2567 | if (tp->rcv_nxt == th->th_seq) { |
2568 | tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack - 1, |
2569 | TH_ACK); |
2570 | if (tcp_saveti) |
2571 | m_freem(tcp_saveti); |
2572 | return; |
2573 | } |
2574 | |
2575 | goto dropafterack_ratelim; |
2576 | } |
2577 | |
2578 | /* |
2579 | * If the ACK bit is off we drop the segment and return. |
2580 | */ |
2581 | if ((tiflags & TH_ACK) == 0) { |
2582 | if (tp->t_flags & TF_ACKNOW) |
2583 | goto dropafterack; |
2584 | else |
2585 | goto drop; |
2586 | } |
2587 | |
2588 | /* |
2589 | * Ack processing. |
2590 | */ |
2591 | switch (tp->t_state) { |
2592 | |
2593 | /* |
2594 | * In SYN_RECEIVED state if the ack ACKs our SYN then enter |
2595 | * ESTABLISHED state and continue processing, otherwise |
2596 | * send an RST. |
2597 | */ |
2598 | case TCPS_SYN_RECEIVED: |
2599 | if (SEQ_GT(tp->snd_una, th->th_ack) || |
2600 | SEQ_GT(th->th_ack, tp->snd_max)) |
2601 | goto dropwithreset; |
2602 | TCP_STATINC(TCP_STAT_CONNECTS); |
2603 | soisconnected(so); |
2604 | tcp_established(tp); |
2605 | /* Do window scaling? */ |
2606 | if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == |
2607 | (TF_RCVD_SCALE|TF_REQ_SCALE)) { |
2608 | tp->snd_scale = tp->requested_s_scale; |
2609 | tp->rcv_scale = tp->request_r_scale; |
2610 | } |
2611 | TCP_REASS_LOCK(tp); |
2612 | (void) tcp_reass(tp, NULL, NULL, &tlen); |
2613 | tp->snd_wl1 = th->th_seq - 1; |
2614 | /* fall into ... */ |
2615 | |
2616 | /* |
2617 | * In ESTABLISHED state: drop duplicate ACKs; ACK out of range |
2618 | * ACKs. If the ack is in the range |
2619 | * tp->snd_una < th->th_ack <= tp->snd_max |
2620 | * then advance tp->snd_una to th->th_ack and drop |
2621 | * data from the retransmission queue. If this ACK reflects |
2622 | * more up to date window information we update our window information. |
2623 | */ |
2624 | case TCPS_ESTABLISHED: |
2625 | case TCPS_FIN_WAIT_1: |
2626 | case TCPS_FIN_WAIT_2: |
2627 | case TCPS_CLOSE_WAIT: |
2628 | case TCPS_CLOSING: |
2629 | case TCPS_LAST_ACK: |
2630 | case TCPS_TIME_WAIT: |
2631 | |
2632 | if (SEQ_LEQ(th->th_ack, tp->snd_una)) { |
2633 | if (tlen == 0 && !dupseg && tiwin == tp->snd_wnd) { |
2634 | TCP_STATINC(TCP_STAT_RCVDUPACK); |
2635 | /* |
2636 | * If we have outstanding data (other than |
2637 | * a window probe), this is a completely |
2638 | * duplicate ack (ie, window info didn't |
2639 | * change), the ack is the biggest we've |
2640 | * seen and we've seen exactly our rexmt |
2641 | * threshhold of them, assume a packet |
2642 | * has been dropped and retransmit it. |
2643 | * Kludge snd_nxt & the congestion |
2644 | * window so we send only this one |
2645 | * packet. |
2646 | */ |
2647 | if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 || |
2648 | th->th_ack != tp->snd_una) |
2649 | tp->t_dupacks = 0; |
2650 | else if (tp->t_partialacks < 0 && |
2651 | (++tp->t_dupacks == tcprexmtthresh || |
2652 | TCP_FACK_FASTRECOV(tp))) { |
2653 | /* |
2654 | * Do the fast retransmit, and adjust |
2655 | * congestion control paramenters. |
2656 | */ |
2657 | if (tp->t_congctl->fast_retransmit(tp, th)) { |
2658 | /* False fast retransmit */ |
2659 | break; |
2660 | } else |
2661 | goto drop; |
2662 | } else if (tp->t_dupacks > tcprexmtthresh) { |
2663 | tp->snd_cwnd += tp->t_segsz; |
2664 | KERNEL_LOCK(1, NULL); |
2665 | (void) tcp_output(tp); |
2666 | KERNEL_UNLOCK_ONE(NULL); |
2667 | goto drop; |
2668 | } |
2669 | } else { |
2670 | /* |
2671 | * If the ack appears to be very old, only |
2672 | * allow data that is in-sequence. This |
2673 | * makes it somewhat more difficult to insert |
2674 | * forged data by guessing sequence numbers. |
2675 | * Sent an ack to try to update the send |
2676 | * sequence number on the other side. |
2677 | */ |
2678 | if (tlen && th->th_seq != tp->rcv_nxt && |
2679 | SEQ_LT(th->th_ack, |
2680 | tp->snd_una - tp->max_sndwnd)) |
2681 | goto dropafterack; |
2682 | } |
2683 | break; |
2684 | } |
2685 | /* |
2686 | * If the congestion window was inflated to account |
2687 | * for the other side's cached packets, retract it. |
2688 | */ |
2689 | tp->t_congctl->fast_retransmit_newack(tp, th); |
2690 | |
2691 | if (SEQ_GT(th->th_ack, tp->snd_max)) { |
2692 | TCP_STATINC(TCP_STAT_RCVACKTOOMUCH); |
2693 | goto dropafterack; |
2694 | } |
2695 | acked = th->th_ack - tp->snd_una; |
2696 | tcps = TCP_STAT_GETREF(); |
2697 | tcps[TCP_STAT_RCVACKPACK]++; |
2698 | tcps[TCP_STAT_RCVACKBYTE] += acked; |
2699 | TCP_STAT_PUTREF(); |
2700 | |
2701 | /* |
2702 | * If we have a timestamp reply, update smoothed |
2703 | * round trip time. If no timestamp is present but |
2704 | * transmit timer is running and timed sequence |
2705 | * number was acked, update smoothed round trip time. |
2706 | * Since we now have an rtt measurement, cancel the |
2707 | * timer backoff (cf., Phil Karn's retransmit alg.). |
2708 | * Recompute the initial retransmit timer. |
2709 | */ |
2710 | if (ts_rtt) |
2711 | tcp_xmit_timer(tp, ts_rtt - 1); |
2712 | else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) |
2713 | tcp_xmit_timer(tp, tcp_now - tp->t_rtttime); |
2714 | |
2715 | /* |
2716 | * If all outstanding data is acked, stop retransmit |
2717 | * timer and remember to restart (more output or persist). |
2718 | * If there is more data to be acked, restart retransmit |
2719 | * timer, using current (possibly backed-off) value. |
2720 | */ |
2721 | if (th->th_ack == tp->snd_max) { |
2722 | TCP_TIMER_DISARM(tp, TCPT_REXMT); |
2723 | needoutput = 1; |
2724 | } else if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) |
2725 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
2726 | |
2727 | /* |
2728 | * New data has been acked, adjust the congestion window. |
2729 | */ |
2730 | tp->t_congctl->newack(tp, th); |
2731 | |
2732 | nd6_hint(tp); |
2733 | if (acked > so->so_snd.sb_cc) { |
2734 | tp->snd_wnd -= so->so_snd.sb_cc; |
2735 | sbdrop(&so->so_snd, (int)so->so_snd.sb_cc); |
2736 | ourfinisacked = 1; |
2737 | } else { |
2738 | if (acked > (tp->t_lastoff - tp->t_inoff)) |
2739 | tp->t_lastm = NULL; |
2740 | sbdrop(&so->so_snd, acked); |
2741 | tp->t_lastoff -= acked; |
2742 | if (tp->snd_wnd > acked) |
2743 | tp->snd_wnd -= acked; |
2744 | else |
2745 | tp->snd_wnd = 0; |
2746 | ourfinisacked = 0; |
2747 | } |
2748 | sowwakeup(so); |
2749 | |
2750 | icmp_check(tp, th, acked); |
2751 | |
2752 | tp->snd_una = th->th_ack; |
2753 | if (SEQ_GT(tp->snd_una, tp->snd_fack)) |
2754 | tp->snd_fack = tp->snd_una; |
2755 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
2756 | tp->snd_nxt = tp->snd_una; |
2757 | if (SEQ_LT(tp->snd_high, tp->snd_una)) |
2758 | tp->snd_high = tp->snd_una; |
2759 | |
2760 | switch (tp->t_state) { |
2761 | |
2762 | /* |
2763 | * In FIN_WAIT_1 STATE in addition to the processing |
2764 | * for the ESTABLISHED state if our FIN is now acknowledged |
2765 | * then enter FIN_WAIT_2. |
2766 | */ |
2767 | case TCPS_FIN_WAIT_1: |
2768 | if (ourfinisacked) { |
2769 | /* |
2770 | * If we can't receive any more |
2771 | * data, then closing user can proceed. |
2772 | * Starting the timer is contrary to the |
2773 | * specification, but if we don't get a FIN |
2774 | * we'll hang forever. |
2775 | */ |
2776 | if (so->so_state & SS_CANTRCVMORE) { |
2777 | soisdisconnected(so); |
2778 | if (tp->t_maxidle > 0) |
2779 | TCP_TIMER_ARM(tp, TCPT_2MSL, |
2780 | tp->t_maxidle); |
2781 | } |
2782 | tp->t_state = TCPS_FIN_WAIT_2; |
2783 | } |
2784 | break; |
2785 | |
2786 | /* |
2787 | * In CLOSING STATE in addition to the processing for |
2788 | * the ESTABLISHED state if the ACK acknowledges our FIN |
2789 | * then enter the TIME-WAIT state, otherwise ignore |
2790 | * the segment. |
2791 | */ |
2792 | case TCPS_CLOSING: |
2793 | if (ourfinisacked) { |
2794 | tp->t_state = TCPS_TIME_WAIT; |
2795 | tcp_canceltimers(tp); |
2796 | TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * tp->t_msl); |
2797 | soisdisconnected(so); |
2798 | } |
2799 | break; |
2800 | |
2801 | /* |
2802 | * In LAST_ACK, we may still be waiting for data to drain |
2803 | * and/or to be acked, as well as for the ack of our FIN. |
2804 | * If our FIN is now acknowledged, delete the TCB, |
2805 | * enter the closed state and return. |
2806 | */ |
2807 | case TCPS_LAST_ACK: |
2808 | if (ourfinisacked) { |
2809 | tp = tcp_close(tp); |
2810 | goto drop; |
2811 | } |
2812 | break; |
2813 | |
2814 | /* |
2815 | * In TIME_WAIT state the only thing that should arrive |
2816 | * is a retransmission of the remote FIN. Acknowledge |
2817 | * it and restart the finack timer. |
2818 | */ |
2819 | case TCPS_TIME_WAIT: |
2820 | TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * tp->t_msl); |
2821 | goto dropafterack; |
2822 | } |
2823 | } |
2824 | |
2825 | step6: |
2826 | /* |
2827 | * Update window information. |
2828 | * Don't look at window if no ACK: TAC's send garbage on first SYN. |
2829 | */ |
2830 | if ((tiflags & TH_ACK) && (SEQ_LT(tp->snd_wl1, th->th_seq) || |
2831 | (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) || |
2832 | (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) { |
2833 | /* keep track of pure window updates */ |
2834 | if (tlen == 0 && |
2835 | tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) |
2836 | TCP_STATINC(TCP_STAT_RCVWINUPD); |
2837 | tp->snd_wnd = tiwin; |
2838 | tp->snd_wl1 = th->th_seq; |
2839 | tp->snd_wl2 = th->th_ack; |
2840 | if (tp->snd_wnd > tp->max_sndwnd) |
2841 | tp->max_sndwnd = tp->snd_wnd; |
2842 | needoutput = 1; |
2843 | } |
2844 | |
2845 | /* |
2846 | * Process segments with URG. |
2847 | */ |
2848 | if ((tiflags & TH_URG) && th->th_urp && |
2849 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
2850 | /* |
2851 | * This is a kludge, but if we receive and accept |
2852 | * random urgent pointers, we'll crash in |
2853 | * soreceive. It's hard to imagine someone |
2854 | * actually wanting to send this much urgent data. |
2855 | */ |
2856 | if (th->th_urp + so->so_rcv.sb_cc > sb_max) { |
2857 | th->th_urp = 0; /* XXX */ |
2858 | tiflags &= ~TH_URG; /* XXX */ |
2859 | goto dodata; /* XXX */ |
2860 | } |
2861 | /* |
2862 | * If this segment advances the known urgent pointer, |
2863 | * then mark the data stream. This should not happen |
2864 | * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since |
2865 | * a FIN has been received from the remote side. |
2866 | * In these states we ignore the URG. |
2867 | * |
2868 | * According to RFC961 (Assigned Protocols), |
2869 | * the urgent pointer points to the last octet |
2870 | * of urgent data. We continue, however, |
2871 | * to consider it to indicate the first octet |
2872 | * of data past the urgent section as the original |
2873 | * spec states (in one of two places). |
2874 | */ |
2875 | if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) { |
2876 | tp->rcv_up = th->th_seq + th->th_urp; |
2877 | so->so_oobmark = so->so_rcv.sb_cc + |
2878 | (tp->rcv_up - tp->rcv_nxt) - 1; |
2879 | if (so->so_oobmark == 0) |
2880 | so->so_state |= SS_RCVATMARK; |
2881 | sohasoutofband(so); |
2882 | tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA); |
2883 | } |
2884 | /* |
2885 | * Remove out of band data so doesn't get presented to user. |
2886 | * This can happen independent of advancing the URG pointer, |
2887 | * but if two URG's are pending at once, some out-of-band |
2888 | * data may creep in... ick. |
2889 | */ |
2890 | if (th->th_urp <= (u_int16_t) tlen |
2891 | #ifdef SO_OOBINLINE |
2892 | && (so->so_options & SO_OOBINLINE) == 0 |
2893 | #endif |
2894 | ) |
2895 | tcp_pulloutofband(so, th, m, hdroptlen); |
2896 | } else |
2897 | /* |
2898 | * If no out of band data is expected, |
2899 | * pull receive urgent pointer along |
2900 | * with the receive window. |
2901 | */ |
2902 | if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) |
2903 | tp->rcv_up = tp->rcv_nxt; |
2904 | dodata: /* XXX */ |
2905 | |
2906 | /* |
2907 | * Process the segment text, merging it into the TCP sequencing queue, |
2908 | * and arranging for acknowledgement of receipt if necessary. |
2909 | * This process logically involves adjusting tp->rcv_wnd as data |
2910 | * is presented to the user (this happens in tcp_usrreq.c, |
2911 | * tcp_rcvd()). If a FIN has already been received on this |
2912 | * connection then we just ignore the text. |
2913 | */ |
2914 | if ((tlen || (tiflags & TH_FIN)) && |
2915 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
2916 | /* |
2917 | * Insert segment ti into reassembly queue of tcp with |
2918 | * control block tp. Return TH_FIN if reassembly now includes |
2919 | * a segment with FIN. The macro form does the common case |
2920 | * inline (segment is the next to be received on an |
2921 | * established connection, and the queue is empty), |
2922 | * avoiding linkage into and removal from the queue and |
2923 | * repetition of various conversions. |
2924 | * Set DELACK for segments received in order, but ack |
2925 | * immediately when segments are out of order |
2926 | * (so fast retransmit can work). |
2927 | */ |
2928 | /* NOTE: this was TCP_REASS() macro, but used only once */ |
2929 | TCP_REASS_LOCK(tp); |
2930 | if (th->th_seq == tp->rcv_nxt && |
2931 | TAILQ_FIRST(&tp->segq) == NULL && |
2932 | tp->t_state == TCPS_ESTABLISHED) { |
2933 | tcp_setup_ack(tp, th); |
2934 | tp->rcv_nxt += tlen; |
2935 | tiflags = th->th_flags & TH_FIN; |
2936 | tcps = TCP_STAT_GETREF(); |
2937 | tcps[TCP_STAT_RCVPACK]++; |
2938 | tcps[TCP_STAT_RCVBYTE] += tlen; |
2939 | TCP_STAT_PUTREF(); |
2940 | nd6_hint(tp); |
2941 | if (so->so_state & SS_CANTRCVMORE) |
2942 | m_freem(m); |
2943 | else { |
2944 | m_adj(m, hdroptlen); |
2945 | sbappendstream(&(so)->so_rcv, m); |
2946 | } |
2947 | TCP_REASS_UNLOCK(tp); |
2948 | sorwakeup(so); |
2949 | } else { |
2950 | m_adj(m, hdroptlen); |
2951 | tiflags = tcp_reass(tp, th, m, &tlen); |
2952 | tp->t_flags |= TF_ACKNOW; |
2953 | } |
2954 | |
2955 | /* |
2956 | * Note the amount of data that peer has sent into |
2957 | * our window, in order to estimate the sender's |
2958 | * buffer size. |
2959 | */ |
2960 | len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt); |
2961 | } else { |
2962 | m_freem(m); |
2963 | m = NULL; |
2964 | tiflags &= ~TH_FIN; |
2965 | } |
2966 | |
2967 | /* |
2968 | * If FIN is received ACK the FIN and let the user know |
2969 | * that the connection is closing. Ignore a FIN received before |
2970 | * the connection is fully established. |
2971 | */ |
2972 | if ((tiflags & TH_FIN) && TCPS_HAVEESTABLISHED(tp->t_state)) { |
2973 | if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
2974 | socantrcvmore(so); |
2975 | tp->t_flags |= TF_ACKNOW; |
2976 | tp->rcv_nxt++; |
2977 | } |
2978 | switch (tp->t_state) { |
2979 | |
2980 | /* |
2981 | * In ESTABLISHED STATE enter the CLOSE_WAIT state. |
2982 | */ |
2983 | case TCPS_ESTABLISHED: |
2984 | tp->t_state = TCPS_CLOSE_WAIT; |
2985 | break; |
2986 | |
2987 | /* |
2988 | * If still in FIN_WAIT_1 STATE FIN has not been acked so |
2989 | * enter the CLOSING state. |
2990 | */ |
2991 | case TCPS_FIN_WAIT_1: |
2992 | tp->t_state = TCPS_CLOSING; |
2993 | break; |
2994 | |
2995 | /* |
2996 | * In FIN_WAIT_2 state enter the TIME_WAIT state, |
2997 | * starting the time-wait timer, turning off the other |
2998 | * standard timers. |
2999 | */ |
3000 | case TCPS_FIN_WAIT_2: |
3001 | tp->t_state = TCPS_TIME_WAIT; |
3002 | tcp_canceltimers(tp); |
3003 | TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * tp->t_msl); |
3004 | soisdisconnected(so); |
3005 | break; |
3006 | |
3007 | /* |
3008 | * In TIME_WAIT state restart the 2 MSL time_wait timer. |
3009 | */ |
3010 | case TCPS_TIME_WAIT: |
3011 | TCP_TIMER_ARM(tp, TCPT_2MSL, 2 * tp->t_msl); |
3012 | break; |
3013 | } |
3014 | } |
3015 | #ifdef TCP_DEBUG |
3016 | if (so->so_options & SO_DEBUG) |
3017 | tcp_trace(TA_INPUT, ostate, tp, tcp_saveti, 0); |
3018 | #endif |
3019 | |
3020 | /* |
3021 | * Return any desired output. |
3022 | */ |
3023 | if (needoutput || (tp->t_flags & TF_ACKNOW)) { |
3024 | KERNEL_LOCK(1, NULL); |
3025 | (void) tcp_output(tp); |
3026 | KERNEL_UNLOCK_ONE(NULL); |
3027 | } |
3028 | if (tcp_saveti) |
3029 | m_freem(tcp_saveti); |
3030 | |
3031 | if (tp->t_state == TCPS_TIME_WAIT |
3032 | && (so->so_state & SS_NOFDREF) |
3033 | && (tp->t_inpcb || af != AF_INET) |
3034 | && (tp->t_in6pcb || af != AF_INET6) |
3035 | && ((af == AF_INET ? tcp4_vtw_enable : tcp6_vtw_enable) & 1) != 0 |
3036 | && TAILQ_EMPTY(&tp->segq) |
3037 | && vtw_add(af, tp)) { |
3038 | ; |
3039 | } |
3040 | return; |
3041 | |
3042 | badsyn: |
3043 | /* |
3044 | * Received a bad SYN. Increment counters and dropwithreset. |
3045 | */ |
3046 | TCP_STATINC(TCP_STAT_BADSYN); |
3047 | tp = NULL; |
3048 | goto dropwithreset; |
3049 | |
3050 | dropafterack: |
3051 | /* |
3052 | * Generate an ACK dropping incoming segment if it occupies |
3053 | * sequence space, where the ACK reflects our state. |
3054 | */ |
3055 | if (tiflags & TH_RST) |
3056 | goto drop; |
3057 | goto dropafterack2; |
3058 | |
3059 | dropafterack_ratelim: |
3060 | /* |
3061 | * We may want to rate-limit ACKs against SYN/RST attack. |
3062 | */ |
3063 | if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count, |
3064 | tcp_ackdrop_ppslim) == 0) { |
3065 | /* XXX stat */ |
3066 | goto drop; |
3067 | } |
3068 | /* ...fall into dropafterack2... */ |
3069 | |
3070 | dropafterack2: |
3071 | m_freem(m); |
3072 | tp->t_flags |= TF_ACKNOW; |
3073 | KERNEL_LOCK(1, NULL); |
3074 | (void) tcp_output(tp); |
3075 | KERNEL_UNLOCK_ONE(NULL); |
3076 | if (tcp_saveti) |
3077 | m_freem(tcp_saveti); |
3078 | return; |
3079 | |
3080 | dropwithreset_ratelim: |
3081 | /* |
3082 | * We may want to rate-limit RSTs in certain situations, |
3083 | * particularly if we are sending an RST in response to |
3084 | * an attempt to connect to or otherwise communicate with |
3085 | * a port for which we have no socket. |
3086 | */ |
3087 | if (ppsratecheck(&tcp_rst_ppslim_last, &tcp_rst_ppslim_count, |
3088 | tcp_rst_ppslim) == 0) { |
3089 | /* XXX stat */ |
3090 | goto drop; |
3091 | } |
3092 | /* ...fall into dropwithreset... */ |
3093 | |
3094 | dropwithreset: |
3095 | /* |
3096 | * Generate a RST, dropping incoming segment. |
3097 | * Make ACK acceptable to originator of segment. |
3098 | */ |
3099 | if (tiflags & TH_RST) |
3100 | goto drop; |
3101 | |
3102 | switch (af) { |
3103 | #ifdef INET6 |
3104 | case AF_INET6: |
3105 | /* For following calls to tcp_respond */ |
3106 | if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) |
3107 | goto drop; |
3108 | break; |
3109 | #endif /* INET6 */ |
3110 | case AF_INET: |
3111 | if (IN_MULTICAST(ip->ip_dst.s_addr) || |
3112 | in_broadcast(ip->ip_dst, m_get_rcvif_NOMPSAFE(m))) |
3113 | goto drop; |
3114 | } |
3115 | |
3116 | if (tiflags & TH_ACK) |
3117 | (void)tcp_respond(tp, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); |
3118 | else { |
3119 | if (tiflags & TH_SYN) |
3120 | tlen++; |
3121 | (void)tcp_respond(tp, m, m, th, th->th_seq + tlen, (tcp_seq)0, |
3122 | TH_RST|TH_ACK); |
3123 | } |
3124 | if (tcp_saveti) |
3125 | m_freem(tcp_saveti); |
3126 | return; |
3127 | |
3128 | badcsum: |
3129 | drop: |
3130 | /* |
3131 | * Drop space held by incoming segment and return. |
3132 | */ |
3133 | if (tp) { |
3134 | if (tp->t_inpcb) |
3135 | so = tp->t_inpcb->inp_socket; |
3136 | #ifdef INET6 |
3137 | else if (tp->t_in6pcb) |
3138 | so = tp->t_in6pcb->in6p_socket; |
3139 | #endif |
3140 | else |
3141 | so = NULL; |
3142 | #ifdef TCP_DEBUG |
3143 | if (so && (so->so_options & SO_DEBUG) != 0) |
3144 | tcp_trace(TA_DROP, ostate, tp, tcp_saveti, 0); |
3145 | #endif |
3146 | } |
3147 | if (tcp_saveti) |
3148 | m_freem(tcp_saveti); |
3149 | m_freem(m); |
3150 | return; |
3151 | } |
3152 | |
3153 | #ifdef TCP_SIGNATURE |
3154 | int |
3155 | tcp_signature_apply(void *fstate, void *data, u_int len) |
3156 | { |
3157 | |
3158 | MD5Update(fstate, (u_char *)data, len); |
3159 | return (0); |
3160 | } |
3161 | |
3162 | struct secasvar * |
3163 | tcp_signature_getsav(struct mbuf *m, struct tcphdr *th) |
3164 | { |
3165 | struct ip *ip; |
3166 | struct ip6_hdr *ip6; |
3167 | |
3168 | ip = mtod(m, struct ip *); |
3169 | switch (ip->ip_v) { |
3170 | case 4: |
3171 | ip = mtod(m, struct ip *); |
3172 | ip6 = NULL; |
3173 | break; |
3174 | case 6: |
3175 | ip = NULL; |
3176 | ip6 = mtod(m, struct ip6_hdr *); |
3177 | break; |
3178 | default: |
3179 | return (NULL); |
3180 | } |
3181 | |
3182 | #ifdef IPSEC |
3183 | if (ipsec_used) { |
3184 | union sockaddr_union dst; |
3185 | /* Extract the destination from the IP header in the mbuf. */ |
3186 | memset(&dst, 0, sizeof(union sockaddr_union)); |
3187 | if (ip != NULL) { |
3188 | dst.sa.sa_len = sizeof(struct sockaddr_in); |
3189 | dst.sa.sa_family = AF_INET; |
3190 | dst.sin.sin_addr = ip->ip_dst; |
3191 | } else { |
3192 | dst.sa.sa_len = sizeof(struct sockaddr_in6); |
3193 | dst.sa.sa_family = AF_INET6; |
3194 | dst.sin6.sin6_addr = ip6->ip6_dst; |
3195 | } |
3196 | |
3197 | /* |
3198 | * Look up an SADB entry which matches the address of the peer. |
3199 | */ |
3200 | return KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI), 0, 0); |
3201 | } |
3202 | return NULL; |
3203 | #else |
3204 | if (ip) |
3205 | return key_allocsa(AF_INET, (void *)&ip->ip_src, |
3206 | (void *)&ip->ip_dst, IPPROTO_TCP, |
3207 | htonl(TCP_SIG_SPI), 0, 0); |
3208 | else |
3209 | return key_allocsa(AF_INET6, (void *)&ip6->ip6_src, |
3210 | (void *)&ip6->ip6_dst, IPPROTO_TCP, |
3211 | htonl(TCP_SIG_SPI), 0, 0); |
3212 | #endif |
3213 | } |
3214 | |
3215 | int |
3216 | tcp_signature(struct mbuf *m, struct tcphdr *th, int thoff, |
3217 | struct secasvar *sav, char *sig) |
3218 | { |
3219 | MD5_CTX ctx; |
3220 | struct ip *ip; |
3221 | struct ipovly *ipovly; |
3222 | #ifdef INET6 |
3223 | struct ip6_hdr *ip6; |
3224 | struct ip6_hdr_pseudo ip6pseudo; |
3225 | #endif /* INET6 */ |
3226 | struct ippseudo ippseudo; |
3227 | struct tcphdr th0; |
3228 | int l, tcphdrlen; |
3229 | |
3230 | if (sav == NULL) |
3231 | return (-1); |
3232 | |
3233 | tcphdrlen = th->th_off * 4; |
3234 | |
3235 | switch (mtod(m, struct ip *)->ip_v) { |
3236 | case 4: |
3237 | MD5Init(&ctx); |
3238 | ip = mtod(m, struct ip *); |
3239 | memset(&ippseudo, 0, sizeof(ippseudo)); |
3240 | ipovly = (struct ipovly *)ip; |
3241 | ippseudo.ippseudo_src = ipovly->ih_src; |
3242 | ippseudo.ippseudo_dst = ipovly->ih_dst; |
3243 | ippseudo.ippseudo_pad = 0; |
3244 | ippseudo.ippseudo_p = IPPROTO_TCP; |
3245 | ippseudo.ippseudo_len = htons(m->m_pkthdr.len - thoff); |
3246 | MD5Update(&ctx, (char *)&ippseudo, sizeof(ippseudo)); |
3247 | break; |
3248 | #if INET6 |
3249 | case 6: |
3250 | MD5Init(&ctx); |
3251 | ip6 = mtod(m, struct ip6_hdr *); |
3252 | memset(&ip6pseudo, 0, sizeof(ip6pseudo)); |
3253 | ip6pseudo.ip6ph_src = ip6->ip6_src; |
3254 | in6_clearscope(&ip6pseudo.ip6ph_src); |
3255 | ip6pseudo.ip6ph_dst = ip6->ip6_dst; |
3256 | in6_clearscope(&ip6pseudo.ip6ph_dst); |
3257 | ip6pseudo.ip6ph_len = htons(m->m_pkthdr.len - thoff); |
3258 | ip6pseudo.ip6ph_nxt = IPPROTO_TCP; |
3259 | MD5Update(&ctx, (char *)&ip6pseudo, sizeof(ip6pseudo)); |
3260 | break; |
3261 | #endif /* INET6 */ |
3262 | default: |
3263 | return (-1); |
3264 | } |
3265 | |
3266 | th0 = *th; |
3267 | th0.th_sum = 0; |
3268 | MD5Update(&ctx, (char *)&th0, sizeof(th0)); |
3269 | |
3270 | l = m->m_pkthdr.len - thoff - tcphdrlen; |
3271 | if (l > 0) |
3272 | m_apply(m, thoff + tcphdrlen, |
3273 | m->m_pkthdr.len - thoff - tcphdrlen, |
3274 | tcp_signature_apply, &ctx); |
3275 | |
3276 | MD5Update(&ctx, _KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth)); |
3277 | MD5Final(sig, &ctx); |
3278 | |
3279 | return (0); |
3280 | } |
3281 | #endif |
3282 | |
3283 | /* |
3284 | * tcp_dooptions: parse and process tcp options. |
3285 | * |
3286 | * returns -1 if this segment should be dropped. (eg. wrong signature) |
3287 | * otherwise returns 0. |
3288 | */ |
3289 | |
3290 | static int |
3291 | tcp_dooptions(struct tcpcb *tp, const u_char *cp, int cnt, |
3292 | struct tcphdr *th, |
3293 | struct mbuf *m, int toff, struct tcp_opt_info *oi) |
3294 | { |
3295 | u_int16_t mss; |
3296 | int opt, optlen = 0; |
3297 | #ifdef TCP_SIGNATURE |
3298 | void *sigp = NULL; |
3299 | char sigbuf[TCP_SIGLEN]; |
3300 | struct secasvar *sav = NULL; |
3301 | #endif |
3302 | |
3303 | for (; cp && cnt > 0; cnt -= optlen, cp += optlen) { |
3304 | opt = cp[0]; |
3305 | if (opt == TCPOPT_EOL) |
3306 | break; |
3307 | if (opt == TCPOPT_NOP) |
3308 | optlen = 1; |
3309 | else { |
3310 | if (cnt < 2) |
3311 | break; |
3312 | optlen = cp[1]; |
3313 | if (optlen < 2 || optlen > cnt) |
3314 | break; |
3315 | } |
3316 | switch (opt) { |
3317 | |
3318 | default: |
3319 | continue; |
3320 | |
3321 | case TCPOPT_MAXSEG: |
3322 | if (optlen != TCPOLEN_MAXSEG) |
3323 | continue; |
3324 | if (!(th->th_flags & TH_SYN)) |
3325 | continue; |
3326 | if (TCPS_HAVERCVDSYN(tp->t_state)) |
3327 | continue; |
3328 | bcopy(cp + 2, &mss, sizeof(mss)); |
3329 | oi->maxseg = ntohs(mss); |
3330 | break; |
3331 | |
3332 | case TCPOPT_WINDOW: |
3333 | if (optlen != TCPOLEN_WINDOW) |
3334 | continue; |
3335 | if (!(th->th_flags & TH_SYN)) |
3336 | continue; |
3337 | if (TCPS_HAVERCVDSYN(tp->t_state)) |
3338 | continue; |
3339 | tp->t_flags |= TF_RCVD_SCALE; |
3340 | tp->requested_s_scale = cp[2]; |
3341 | if (tp->requested_s_scale > TCP_MAX_WINSHIFT) { |
3342 | char buf[INET6_ADDRSTRLEN]; |
3343 | struct ip *ip = mtod(m, struct ip *); |
3344 | #ifdef INET6 |
3345 | struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); |
3346 | #endif |
3347 | if (ip) |
3348 | in_print(buf, sizeof(buf), |
3349 | &ip->ip_src); |
3350 | #ifdef INET6 |
3351 | else if (ip6) |
3352 | in6_print(buf, sizeof(buf), |
3353 | &ip6->ip6_src); |
3354 | #endif |
3355 | else |
3356 | strlcpy(buf, "(unknown)" , sizeof(buf)); |
3357 | log(LOG_ERR, "TCP: invalid wscale %d from %s, " |
3358 | "assuming %d\n" , |
3359 | tp->requested_s_scale, buf, |
3360 | TCP_MAX_WINSHIFT); |
3361 | tp->requested_s_scale = TCP_MAX_WINSHIFT; |
3362 | } |
3363 | break; |
3364 | |
3365 | case TCPOPT_TIMESTAMP: |
3366 | if (optlen != TCPOLEN_TIMESTAMP) |
3367 | continue; |
3368 | oi->ts_present = 1; |
3369 | bcopy(cp + 2, &oi->ts_val, sizeof(oi->ts_val)); |
3370 | NTOHL(oi->ts_val); |
3371 | bcopy(cp + 6, &oi->ts_ecr, sizeof(oi->ts_ecr)); |
3372 | NTOHL(oi->ts_ecr); |
3373 | |
3374 | if (!(th->th_flags & TH_SYN)) |
3375 | continue; |
3376 | if (TCPS_HAVERCVDSYN(tp->t_state)) |
3377 | continue; |
3378 | /* |
3379 | * A timestamp received in a SYN makes |
3380 | * it ok to send timestamp requests and replies. |
3381 | */ |
3382 | tp->t_flags |= TF_RCVD_TSTMP; |
3383 | tp->ts_recent = oi->ts_val; |
3384 | tp->ts_recent_age = tcp_now; |
3385 | break; |
3386 | |
3387 | case TCPOPT_SACK_PERMITTED: |
3388 | if (optlen != TCPOLEN_SACK_PERMITTED) |
3389 | continue; |
3390 | if (!(th->th_flags & TH_SYN)) |
3391 | continue; |
3392 | if (TCPS_HAVERCVDSYN(tp->t_state)) |
3393 | continue; |
3394 | if (tcp_do_sack) { |
3395 | tp->t_flags |= TF_SACK_PERMIT; |
3396 | tp->t_flags |= TF_WILL_SACK; |
3397 | } |
3398 | break; |
3399 | |
3400 | case TCPOPT_SACK: |
3401 | tcp_sack_option(tp, th, cp, optlen); |
3402 | break; |
3403 | #ifdef TCP_SIGNATURE |
3404 | case TCPOPT_SIGNATURE: |
3405 | if (optlen != TCPOLEN_SIGNATURE) |
3406 | continue; |
3407 | if (sigp && memcmp(sigp, cp + 2, TCP_SIGLEN)) |
3408 | return (-1); |
3409 | |
3410 | sigp = sigbuf; |
3411 | memcpy(sigbuf, cp + 2, TCP_SIGLEN); |
3412 | tp->t_flags |= TF_SIGNATURE; |
3413 | break; |
3414 | #endif |
3415 | } |
3416 | } |
3417 | |
3418 | #ifndef TCP_SIGNATURE |
3419 | return 0; |
3420 | #else |
3421 | if (tp->t_flags & TF_SIGNATURE) { |
3422 | |
3423 | sav = tcp_signature_getsav(m, th); |
3424 | |
3425 | if (sav == NULL && tp->t_state == TCPS_LISTEN) |
3426 | return (-1); |
3427 | } |
3428 | |
3429 | if ((sigp ? TF_SIGNATURE : 0) ^ (tp->t_flags & TF_SIGNATURE)) |
3430 | goto out; |
3431 | |
3432 | if (sigp) { |
3433 | char sig[TCP_SIGLEN]; |
3434 | |
3435 | tcp_fields_to_net(th); |
3436 | if (tcp_signature(m, th, toff, sav, sig) < 0) { |
3437 | tcp_fields_to_host(th); |
3438 | goto out; |
3439 | } |
3440 | tcp_fields_to_host(th); |
3441 | |
3442 | if (memcmp(sig, sigp, TCP_SIGLEN)) { |
3443 | TCP_STATINC(TCP_STAT_BADSIG); |
3444 | goto out; |
3445 | } else |
3446 | TCP_STATINC(TCP_STAT_GOODSIG); |
3447 | |
3448 | key_sa_recordxfer(sav, m); |
3449 | KEY_FREESAV(&sav); |
3450 | } |
3451 | return 0; |
3452 | out: |
3453 | if (sav != NULL) |
3454 | KEY_FREESAV(&sav); |
3455 | return -1; |
3456 | #endif |
3457 | } |
3458 | |
3459 | /* |
3460 | * Pull out of band byte out of a segment so |
3461 | * it doesn't appear in the user's data queue. |
3462 | * It is still reflected in the segment length for |
3463 | * sequencing purposes. |
3464 | */ |
3465 | void |
3466 | tcp_pulloutofband(struct socket *so, struct tcphdr *th, |
3467 | struct mbuf *m, int off) |
3468 | { |
3469 | int cnt = off + th->th_urp - 1; |
3470 | |
3471 | while (cnt >= 0) { |
3472 | if (m->m_len > cnt) { |
3473 | char *cp = mtod(m, char *) + cnt; |
3474 | struct tcpcb *tp = sototcpcb(so); |
3475 | |
3476 | tp->t_iobc = *cp; |
3477 | tp->t_oobflags |= TCPOOB_HAVEDATA; |
3478 | bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); |
3479 | m->m_len--; |
3480 | return; |
3481 | } |
3482 | cnt -= m->m_len; |
3483 | m = m->m_next; |
3484 | if (m == 0) |
3485 | break; |
3486 | } |
3487 | panic("tcp_pulloutofband" ); |
3488 | } |
3489 | |
3490 | /* |
3491 | * Collect new round-trip time estimate |
3492 | * and update averages and current timeout. |
3493 | * |
3494 | * rtt is in units of slow ticks (typically 500 ms) -- essentially the |
3495 | * difference of two timestamps. |
3496 | */ |
3497 | void |
3498 | tcp_xmit_timer(struct tcpcb *tp, uint32_t rtt) |
3499 | { |
3500 | int32_t delta; |
3501 | |
3502 | TCP_STATINC(TCP_STAT_RTTUPDATED); |
3503 | if (tp->t_srtt != 0) { |
3504 | /* |
3505 | * Compute the amount to add to srtt for smoothing, |
3506 | * *alpha, or 2^(-TCP_RTT_SHIFT). Because |
3507 | * srtt is stored in 1/32 slow ticks, we conceptually |
3508 | * shift left 5 bits, subtract srtt to get the |
3509 | * diference, and then shift right by TCP_RTT_SHIFT |
3510 | * (3) to obtain 1/8 of the difference. |
3511 | */ |
3512 | delta = (rtt << 2) - (tp->t_srtt >> TCP_RTT_SHIFT); |
3513 | /* |
3514 | * This can never happen, because delta's lowest |
3515 | * possible value is 1/8 of t_srtt. But if it does, |
3516 | * set srtt to some reasonable value, here chosen |
3517 | * as 1/8 tick. |
3518 | */ |
3519 | if ((tp->t_srtt += delta) <= 0) |
3520 | tp->t_srtt = 1 << 2; |
3521 | /* |
3522 | * RFC2988 requires that rttvar be updated first. |
3523 | * This code is compliant because "delta" is the old |
3524 | * srtt minus the new observation (scaled). |
3525 | * |
3526 | * RFC2988 says: |
3527 | * rttvar = (1-beta) * rttvar + beta * |srtt-observed| |
3528 | * |
3529 | * delta is in units of 1/32 ticks, and has then been |
3530 | * divided by 8. This is equivalent to being in 1/16s |
3531 | * units and divided by 4. Subtract from it 1/4 of |
3532 | * the existing rttvar to form the (signed) amount to |
3533 | * adjust. |
3534 | */ |
3535 | if (delta < 0) |
3536 | delta = -delta; |
3537 | delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT); |
3538 | /* |
3539 | * As with srtt, this should never happen. There is |
3540 | * no support in RFC2988 for this operation. But 1/4s |
3541 | * as rttvar when faced with something arguably wrong |
3542 | * is ok. |
3543 | */ |
3544 | if ((tp->t_rttvar += delta) <= 0) |
3545 | tp->t_rttvar = 1 << 2; |
3546 | |
3547 | /* |
3548 | * If srtt exceeds .01 second, ensure we use the 'remote' MSL |
3549 | * Problem is: it doesn't work. Disabled by defaulting |
3550 | * tcp_rttlocal to 0; see corresponding code in |
3551 | * tcp_subr that selects local vs remote in a different way. |
3552 | * |
3553 | * The static branch prediction hint here should be removed |
3554 | * when the rtt estimator is fixed and the rtt_enable code |
3555 | * is turned back on. |
3556 | */ |
3557 | if (__predict_false(tcp_rttlocal) && tcp_msl_enable |
3558 | && tp->t_srtt > tcp_msl_remote_threshold |
3559 | && tp->t_msl < tcp_msl_remote) { |
3560 | tp->t_msl = tcp_msl_remote; |
3561 | } |
3562 | } else { |
3563 | /* |
3564 | * This is the first measurement. Per RFC2988, 2.2, |
3565 | * set rtt=R and srtt=R/2. |
3566 | * For srtt, storage representation is 1/32 ticks, |
3567 | * so shift left by 5. |
3568 | * For rttvar, storage representation is 1/16 ticks, |
3569 | * So shift left by 4, but then right by 1 to halve. |
3570 | */ |
3571 | tp->t_srtt = rtt << (TCP_RTT_SHIFT + 2); |
3572 | tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT + 2 - 1); |
3573 | } |
3574 | tp->t_rtttime = 0; |
3575 | tp->t_rxtshift = 0; |
3576 | |
3577 | /* |
3578 | * the retransmit should happen at rtt + 4 * rttvar. |
3579 | * Because of the way we do the smoothing, srtt and rttvar |
3580 | * will each average +1/2 tick of bias. When we compute |
3581 | * the retransmit timer, we want 1/2 tick of rounding and |
3582 | * 1 extra tick because of +-1/2 tick uncertainty in the |
3583 | * firing of the timer. The bias will give us exactly the |
3584 | * 1.5 tick we need. But, because the bias is |
3585 | * statistical, we have to test that we don't drop below |
3586 | * the minimum feasible timer (which is 2 ticks). |
3587 | */ |
3588 | TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), |
3589 | max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX); |
3590 | |
3591 | /* |
3592 | * We received an ack for a packet that wasn't retransmitted; |
3593 | * it is probably safe to discard any error indications we've |
3594 | * received recently. This isn't quite right, but close enough |
3595 | * for now (a route might have failed after we sent a segment, |
3596 | * and the return path might not be symmetrical). |
3597 | */ |
3598 | tp->t_softerror = 0; |
3599 | } |
3600 | |
3601 | |
3602 | /* |
3603 | * TCP compressed state engine. Currently used to hold compressed |
3604 | * state for SYN_RECEIVED. |
3605 | */ |
3606 | |
3607 | u_long syn_cache_count; |
3608 | u_int32_t syn_hash1, syn_hash2; |
3609 | |
3610 | #define SYN_HASH(sa, sp, dp) \ |
3611 | ((((sa)->s_addr^syn_hash1)*(((((u_int32_t)(dp))<<16) + \ |
3612 | ((u_int32_t)(sp)))^syn_hash2))) |
3613 | #ifndef INET6 |
3614 | #define SYN_HASHALL(hash, src, dst) \ |
3615 | do { \ |
3616 | hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ |
3617 | ((const struct sockaddr_in *)(src))->sin_port, \ |
3618 | ((const struct sockaddr_in *)(dst))->sin_port); \ |
3619 | } while (/*CONSTCOND*/ 0) |
3620 | #else |
3621 | #define SYN_HASH6(sa, sp, dp) \ |
3622 | ((((sa)->s6_addr32[0] ^ (sa)->s6_addr32[3] ^ syn_hash1) * \ |
3623 | (((((u_int32_t)(dp))<<16) + ((u_int32_t)(sp)))^syn_hash2)) \ |
3624 | & 0x7fffffff) |
3625 | |
3626 | #define SYN_HASHALL(hash, src, dst) \ |
3627 | do { \ |
3628 | switch ((src)->sa_family) { \ |
3629 | case AF_INET: \ |
3630 | hash = SYN_HASH(&((const struct sockaddr_in *)(src))->sin_addr, \ |
3631 | ((const struct sockaddr_in *)(src))->sin_port, \ |
3632 | ((const struct sockaddr_in *)(dst))->sin_port); \ |
3633 | break; \ |
3634 | case AF_INET6: \ |
3635 | hash = SYN_HASH6(&((const struct sockaddr_in6 *)(src))->sin6_addr, \ |
3636 | ((const struct sockaddr_in6 *)(src))->sin6_port, \ |
3637 | ((const struct sockaddr_in6 *)(dst))->sin6_port); \ |
3638 | break; \ |
3639 | default: \ |
3640 | hash = 0; \ |
3641 | } \ |
3642 | } while (/*CONSTCOND*/0) |
3643 | #endif /* INET6 */ |
3644 | |
3645 | static struct pool syn_cache_pool; |
3646 | |
3647 | /* |
3648 | * We don't estimate RTT with SYNs, so each packet starts with the default |
3649 | * RTT and each timer step has a fixed timeout value. |
3650 | */ |
3651 | #define SYN_CACHE_TIMER_ARM(sc) \ |
3652 | do { \ |
3653 | TCPT_RANGESET((sc)->sc_rxtcur, \ |
3654 | TCPTV_SRTTDFLT * tcp_backoff[(sc)->sc_rxtshift], TCPTV_MIN, \ |
3655 | TCPTV_REXMTMAX); \ |
3656 | callout_reset(&(sc)->sc_timer, \ |
3657 | (sc)->sc_rxtcur * (hz / PR_SLOWHZ), syn_cache_timer, (sc)); \ |
3658 | } while (/*CONSTCOND*/0) |
3659 | |
3660 | #define SYN_CACHE_TIMESTAMP(sc) (tcp_now - (sc)->sc_timebase) |
3661 | |
3662 | static inline void |
3663 | syn_cache_rm(struct syn_cache *sc) |
3664 | { |
3665 | TAILQ_REMOVE(&tcp_syn_cache[sc->sc_bucketidx].sch_bucket, |
3666 | sc, sc_bucketq); |
3667 | sc->sc_tp = NULL; |
3668 | LIST_REMOVE(sc, sc_tpq); |
3669 | tcp_syn_cache[sc->sc_bucketidx].sch_length--; |
3670 | callout_stop(&sc->sc_timer); |
3671 | syn_cache_count--; |
3672 | } |
3673 | |
3674 | static inline void |
3675 | syn_cache_put(struct syn_cache *sc) |
3676 | { |
3677 | if (sc->sc_ipopts) |
3678 | (void) m_free(sc->sc_ipopts); |
3679 | rtcache_free(&sc->sc_route); |
3680 | sc->sc_flags |= SCF_DEAD; |
3681 | if (!callout_invoking(&sc->sc_timer)) |
3682 | callout_schedule(&(sc)->sc_timer, 1); |
3683 | } |
3684 | |
3685 | void |
3686 | syn_cache_init(void) |
3687 | { |
3688 | int i; |
3689 | |
3690 | pool_init(&syn_cache_pool, sizeof(struct syn_cache), 0, 0, 0, |
3691 | "synpl" , NULL, IPL_SOFTNET); |
3692 | |
3693 | /* Initialize the hash buckets. */ |
3694 | for (i = 0; i < tcp_syn_cache_size; i++) |
3695 | TAILQ_INIT(&tcp_syn_cache[i].sch_bucket); |
3696 | } |
3697 | |
3698 | void |
3699 | syn_cache_insert(struct syn_cache *sc, struct tcpcb *tp) |
3700 | { |
3701 | struct syn_cache_head *scp; |
3702 | struct syn_cache *sc2; |
3703 | int s; |
3704 | |
3705 | /* |
3706 | * If there are no entries in the hash table, reinitialize |
3707 | * the hash secrets. |
3708 | */ |
3709 | if (syn_cache_count == 0) { |
3710 | syn_hash1 = cprng_fast32(); |
3711 | syn_hash2 = cprng_fast32(); |
3712 | } |
3713 | |
3714 | SYN_HASHALL(sc->sc_hash, &sc->sc_src.sa, &sc->sc_dst.sa); |
3715 | sc->sc_bucketidx = sc->sc_hash % tcp_syn_cache_size; |
3716 | scp = &tcp_syn_cache[sc->sc_bucketidx]; |
3717 | |
3718 | /* |
3719 | * Make sure that we don't overflow the per-bucket |
3720 | * limit or the total cache size limit. |
3721 | */ |
3722 | s = splsoftnet(); |
3723 | if (scp->sch_length >= tcp_syn_bucket_limit) { |
3724 | TCP_STATINC(TCP_STAT_SC_BUCKETOVERFLOW); |
3725 | /* |
3726 | * The bucket is full. Toss the oldest element in the |
3727 | * bucket. This will be the first entry in the bucket. |
3728 | */ |
3729 | sc2 = TAILQ_FIRST(&scp->sch_bucket); |
3730 | #ifdef DIAGNOSTIC |
3731 | /* |
3732 | * This should never happen; we should always find an |
3733 | * entry in our bucket. |
3734 | */ |
3735 | if (sc2 == NULL) |
3736 | panic("syn_cache_insert: bucketoverflow: impossible" ); |
3737 | #endif |
3738 | syn_cache_rm(sc2); |
3739 | syn_cache_put(sc2); /* calls pool_put but see spl above */ |
3740 | } else if (syn_cache_count >= tcp_syn_cache_limit) { |
3741 | struct syn_cache_head *scp2, *sce; |
3742 | |
3743 | TCP_STATINC(TCP_STAT_SC_OVERFLOWED); |
3744 | /* |
3745 | * The cache is full. Toss the oldest entry in the |
3746 | * first non-empty bucket we can find. |
3747 | * |
3748 | * XXX We would really like to toss the oldest |
3749 | * entry in the cache, but we hope that this |
3750 | * condition doesn't happen very often. |
3751 | */ |
3752 | scp2 = scp; |
3753 | if (TAILQ_EMPTY(&scp2->sch_bucket)) { |
3754 | sce = &tcp_syn_cache[tcp_syn_cache_size]; |
3755 | for (++scp2; scp2 != scp; scp2++) { |
3756 | if (scp2 >= sce) |
3757 | scp2 = &tcp_syn_cache[0]; |
3758 | if (! TAILQ_EMPTY(&scp2->sch_bucket)) |
3759 | break; |
3760 | } |
3761 | #ifdef DIAGNOSTIC |
3762 | /* |
3763 | * This should never happen; we should always find a |
3764 | * non-empty bucket. |
3765 | */ |
3766 | if (scp2 == scp) |
3767 | panic("syn_cache_insert: cacheoverflow: " |
3768 | "impossible" ); |
3769 | #endif |
3770 | } |
3771 | sc2 = TAILQ_FIRST(&scp2->sch_bucket); |
3772 | syn_cache_rm(sc2); |
3773 | syn_cache_put(sc2); /* calls pool_put but see spl above */ |
3774 | } |
3775 | |
3776 | /* |
3777 | * Initialize the entry's timer. |
3778 | */ |
3779 | sc->sc_rxttot = 0; |
3780 | sc->sc_rxtshift = 0; |
3781 | SYN_CACHE_TIMER_ARM(sc); |
3782 | |
3783 | /* Link it from tcpcb entry */ |
3784 | LIST_INSERT_HEAD(&tp->t_sc, sc, sc_tpq); |
3785 | |
3786 | /* Put it into the bucket. */ |
3787 | TAILQ_INSERT_TAIL(&scp->sch_bucket, sc, sc_bucketq); |
3788 | scp->sch_length++; |
3789 | syn_cache_count++; |
3790 | |
3791 | TCP_STATINC(TCP_STAT_SC_ADDED); |
3792 | splx(s); |
3793 | } |
3794 | |
3795 | /* |
3796 | * Walk the timer queues, looking for SYN,ACKs that need to be retransmitted. |
3797 | * If we have retransmitted an entry the maximum number of times, expire |
3798 | * that entry. |
3799 | */ |
3800 | void |
3801 | syn_cache_timer(void *arg) |
3802 | { |
3803 | struct syn_cache *sc = arg; |
3804 | |
3805 | mutex_enter(softnet_lock); |
3806 | KERNEL_LOCK(1, NULL); |
3807 | callout_ack(&sc->sc_timer); |
3808 | |
3809 | if (__predict_false(sc->sc_flags & SCF_DEAD)) { |
3810 | TCP_STATINC(TCP_STAT_SC_DELAYED_FREE); |
3811 | callout_destroy(&sc->sc_timer); |
3812 | pool_put(&syn_cache_pool, sc); |
3813 | KERNEL_UNLOCK_ONE(NULL); |
3814 | mutex_exit(softnet_lock); |
3815 | return; |
3816 | } |
3817 | |
3818 | if (__predict_false(sc->sc_rxtshift == TCP_MAXRXTSHIFT)) { |
3819 | /* Drop it -- too many retransmissions. */ |
3820 | goto dropit; |
3821 | } |
3822 | |
3823 | /* |
3824 | * Compute the total amount of time this entry has |
3825 | * been on a queue. If this entry has been on longer |
3826 | * than the keep alive timer would allow, expire it. |
3827 | */ |
3828 | sc->sc_rxttot += sc->sc_rxtcur; |
3829 | if (sc->sc_rxttot >= tcp_keepinit) |
3830 | goto dropit; |
3831 | |
3832 | TCP_STATINC(TCP_STAT_SC_RETRANSMITTED); |
3833 | (void) syn_cache_respond(sc, NULL); |
3834 | |
3835 | /* Advance the timer back-off. */ |
3836 | sc->sc_rxtshift++; |
3837 | SYN_CACHE_TIMER_ARM(sc); |
3838 | |
3839 | KERNEL_UNLOCK_ONE(NULL); |
3840 | mutex_exit(softnet_lock); |
3841 | return; |
3842 | |
3843 | dropit: |
3844 | TCP_STATINC(TCP_STAT_SC_TIMED_OUT); |
3845 | syn_cache_rm(sc); |
3846 | if (sc->sc_ipopts) |
3847 | (void) m_free(sc->sc_ipopts); |
3848 | rtcache_free(&sc->sc_route); |
3849 | callout_destroy(&sc->sc_timer); |
3850 | pool_put(&syn_cache_pool, sc); |
3851 | KERNEL_UNLOCK_ONE(NULL); |
3852 | mutex_exit(softnet_lock); |
3853 | } |
3854 | |
3855 | /* |
3856 | * Remove syn cache created by the specified tcb entry, |
3857 | * because this does not make sense to keep them |
3858 | * (if there's no tcb entry, syn cache entry will never be used) |
3859 | */ |
3860 | void |
3861 | syn_cache_cleanup(struct tcpcb *tp) |
3862 | { |
3863 | struct syn_cache *sc, *nsc; |
3864 | int s; |
3865 | |
3866 | s = splsoftnet(); |
3867 | |
3868 | for (sc = LIST_FIRST(&tp->t_sc); sc != NULL; sc = nsc) { |
3869 | nsc = LIST_NEXT(sc, sc_tpq); |
3870 | |
3871 | #ifdef DIAGNOSTIC |
3872 | if (sc->sc_tp != tp) |
3873 | panic("invalid sc_tp in syn_cache_cleanup" ); |
3874 | #endif |
3875 | syn_cache_rm(sc); |
3876 | syn_cache_put(sc); /* calls pool_put but see spl above */ |
3877 | } |
3878 | /* just for safety */ |
3879 | LIST_INIT(&tp->t_sc); |
3880 | |
3881 | splx(s); |
3882 | } |
3883 | |
3884 | /* |
3885 | * Find an entry in the syn cache. |
3886 | */ |
3887 | struct syn_cache * |
3888 | syn_cache_lookup(const struct sockaddr *src, const struct sockaddr *dst, |
3889 | struct syn_cache_head **headp) |
3890 | { |
3891 | struct syn_cache *sc; |
3892 | struct syn_cache_head *scp; |
3893 | u_int32_t hash; |
3894 | int s; |
3895 | |
3896 | SYN_HASHALL(hash, src, dst); |
3897 | |
3898 | scp = &tcp_syn_cache[hash % tcp_syn_cache_size]; |
3899 | *headp = scp; |
3900 | s = splsoftnet(); |
3901 | for (sc = TAILQ_FIRST(&scp->sch_bucket); sc != NULL; |
3902 | sc = TAILQ_NEXT(sc, sc_bucketq)) { |
3903 | if (sc->sc_hash != hash) |
3904 | continue; |
3905 | if (!memcmp(&sc->sc_src, src, src->sa_len) && |
3906 | !memcmp(&sc->sc_dst, dst, dst->sa_len)) { |
3907 | splx(s); |
3908 | return (sc); |
3909 | } |
3910 | } |
3911 | splx(s); |
3912 | return (NULL); |
3913 | } |
3914 | |
3915 | /* |
3916 | * This function gets called when we receive an ACK for a |
3917 | * socket in the LISTEN state. We look up the connection |
3918 | * in the syn cache, and if its there, we pull it out of |
3919 | * the cache and turn it into a full-blown connection in |
3920 | * the SYN-RECEIVED state. |
3921 | * |
3922 | * The return values may not be immediately obvious, and their effects |
3923 | * can be subtle, so here they are: |
3924 | * |
3925 | * NULL SYN was not found in cache; caller should drop the |
3926 | * packet and send an RST. |
3927 | * |
3928 | * -1 We were unable to create the new connection, and are |
3929 | * aborting it. An ACK,RST is being sent to the peer |
3930 | * (unless we got screwey sequence numbners; see below), |
3931 | * because the 3-way handshake has been completed. Caller |
3932 | * should not free the mbuf, since we may be using it. If |
3933 | * we are not, we will free it. |
3934 | * |
3935 | * Otherwise, the return value is a pointer to the new socket |
3936 | * associated with the connection. |
3937 | */ |
3938 | struct socket * |
3939 | syn_cache_get(struct sockaddr *src, struct sockaddr *dst, |
3940 | struct tcphdr *th, unsigned int hlen, unsigned int tlen, |
3941 | struct socket *so, struct mbuf *m) |
3942 | { |
3943 | struct syn_cache *sc; |
3944 | struct syn_cache_head *scp; |
3945 | struct inpcb *inp = NULL; |
3946 | #ifdef INET6 |
3947 | struct in6pcb *in6p = NULL; |
3948 | #endif |
3949 | struct tcpcb *tp = 0; |
3950 | int s; |
3951 | struct socket *oso; |
3952 | |
3953 | s = splsoftnet(); |
3954 | if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { |
3955 | splx(s); |
3956 | return (NULL); |
3957 | } |
3958 | |
3959 | /* |
3960 | * Verify the sequence and ack numbers. Try getting the correct |
3961 | * response again. |
3962 | */ |
3963 | if ((th->th_ack != sc->sc_iss + 1) || |
3964 | SEQ_LEQ(th->th_seq, sc->sc_irs) || |
3965 | SEQ_GT(th->th_seq, sc->sc_irs + 1 + sc->sc_win)) { |
3966 | (void) syn_cache_respond(sc, m); |
3967 | splx(s); |
3968 | return ((struct socket *)(-1)); |
3969 | } |
3970 | |
3971 | /* Remove this cache entry */ |
3972 | syn_cache_rm(sc); |
3973 | splx(s); |
3974 | |
3975 | /* |
3976 | * Ok, create the full blown connection, and set things up |
3977 | * as they would have been set up if we had created the |
3978 | * connection when the SYN arrived. If we can't create |
3979 | * the connection, abort it. |
3980 | */ |
3981 | /* |
3982 | * inp still has the OLD in_pcb stuff, set the |
3983 | * v6-related flags on the new guy, too. This is |
3984 | * done particularly for the case where an AF_INET6 |
3985 | * socket is bound only to a port, and a v4 connection |
3986 | * comes in on that port. |
3987 | * we also copy the flowinfo from the original pcb |
3988 | * to the new one. |
3989 | */ |
3990 | oso = so; |
3991 | so = sonewconn(so, true); |
3992 | if (so == NULL) |
3993 | goto resetandabort; |
3994 | |
3995 | switch (so->so_proto->pr_domain->dom_family) { |
3996 | #ifdef INET |
3997 | case AF_INET: |
3998 | inp = sotoinpcb(so); |
3999 | break; |
4000 | #endif |
4001 | #ifdef INET6 |
4002 | case AF_INET6: |
4003 | in6p = sotoin6pcb(so); |
4004 | break; |
4005 | #endif |
4006 | } |
4007 | switch (src->sa_family) { |
4008 | #ifdef INET |
4009 | case AF_INET: |
4010 | if (inp) { |
4011 | inp->inp_laddr = ((struct sockaddr_in *)dst)->sin_addr; |
4012 | inp->inp_lport = ((struct sockaddr_in *)dst)->sin_port; |
4013 | inp->inp_options = ip_srcroute(); |
4014 | in_pcbstate(inp, INP_BOUND); |
4015 | if (inp->inp_options == NULL) { |
4016 | inp->inp_options = sc->sc_ipopts; |
4017 | sc->sc_ipopts = NULL; |
4018 | } |
4019 | } |
4020 | #ifdef INET6 |
4021 | else if (in6p) { |
4022 | /* IPv4 packet to AF_INET6 socket */ |
4023 | memset(&in6p->in6p_laddr, 0, sizeof(in6p->in6p_laddr)); |
4024 | in6p->in6p_laddr.s6_addr16[5] = htons(0xffff); |
4025 | bcopy(&((struct sockaddr_in *)dst)->sin_addr, |
4026 | &in6p->in6p_laddr.s6_addr32[3], |
4027 | sizeof(((struct sockaddr_in *)dst)->sin_addr)); |
4028 | in6p->in6p_lport = ((struct sockaddr_in *)dst)->sin_port; |
4029 | in6totcpcb(in6p)->t_family = AF_INET; |
4030 | if (sotoin6pcb(oso)->in6p_flags & IN6P_IPV6_V6ONLY) |
4031 | in6p->in6p_flags |= IN6P_IPV6_V6ONLY; |
4032 | else |
4033 | in6p->in6p_flags &= ~IN6P_IPV6_V6ONLY; |
4034 | in6_pcbstate(in6p, IN6P_BOUND); |
4035 | } |
4036 | #endif |
4037 | break; |
4038 | #endif |
4039 | #ifdef INET6 |
4040 | case AF_INET6: |
4041 | if (in6p) { |
4042 | in6p->in6p_laddr = ((struct sockaddr_in6 *)dst)->sin6_addr; |
4043 | in6p->in6p_lport = ((struct sockaddr_in6 *)dst)->sin6_port; |
4044 | in6_pcbstate(in6p, IN6P_BOUND); |
4045 | } |
4046 | break; |
4047 | #endif |
4048 | } |
4049 | #ifdef INET6 |
4050 | if (in6p && in6totcpcb(in6p)->t_family == AF_INET6 && sotoinpcb(oso)) { |
4051 | struct in6pcb *oin6p = sotoin6pcb(oso); |
4052 | /* inherit socket options from the listening socket */ |
4053 | in6p->in6p_flags |= (oin6p->in6p_flags & IN6P_CONTROLOPTS); |
4054 | if (in6p->in6p_flags & IN6P_CONTROLOPTS) { |
4055 | m_freem(in6p->in6p_options); |
4056 | in6p->in6p_options = 0; |
4057 | } |
4058 | ip6_savecontrol(in6p, &in6p->in6p_options, |
4059 | mtod(m, struct ip6_hdr *), m); |
4060 | } |
4061 | #endif |
4062 | |
4063 | #if defined(IPSEC) |
4064 | if (ipsec_used) { |
4065 | /* |
4066 | * we make a copy of policy, instead of sharing the policy, for |
4067 | * better behavior in terms of SA lookup and dead SA removal. |
4068 | */ |
4069 | if (inp) { |
4070 | /* copy old policy into new socket's */ |
4071 | if (ipsec_copy_pcbpolicy(sotoinpcb(oso)->inp_sp, |
4072 | inp->inp_sp)) |
4073 | printf("tcp_input: could not copy policy\n" ); |
4074 | } |
4075 | #ifdef INET6 |
4076 | else if (in6p) { |
4077 | /* copy old policy into new socket's */ |
4078 | if (ipsec_copy_pcbpolicy(sotoin6pcb(oso)->in6p_sp, |
4079 | in6p->in6p_sp)) |
4080 | printf("tcp_input: could not copy policy\n" ); |
4081 | } |
4082 | #endif |
4083 | } |
4084 | #endif |
4085 | |
4086 | /* |
4087 | * Give the new socket our cached route reference. |
4088 | */ |
4089 | if (inp) { |
4090 | rtcache_copy(&inp->inp_route, &sc->sc_route); |
4091 | rtcache_free(&sc->sc_route); |
4092 | } |
4093 | #ifdef INET6 |
4094 | else { |
4095 | rtcache_copy(&in6p->in6p_route, &sc->sc_route); |
4096 | rtcache_free(&sc->sc_route); |
4097 | } |
4098 | #endif |
4099 | |
4100 | if (inp) { |
4101 | struct sockaddr_in sin; |
4102 | memcpy(&sin, src, src->sa_len); |
4103 | if (in_pcbconnect(inp, &sin, &lwp0)) { |
4104 | goto resetandabort; |
4105 | } |
4106 | } |
4107 | #ifdef INET6 |
4108 | else if (in6p) { |
4109 | struct sockaddr_in6 sin6; |
4110 | memcpy(&sin6, src, src->sa_len); |
4111 | if (src->sa_family == AF_INET) { |
4112 | /* IPv4 packet to AF_INET6 socket */ |
4113 | in6_sin_2_v4mapsin6((struct sockaddr_in *)src, &sin6); |
4114 | } |
4115 | if (in6_pcbconnect(in6p, &sin6, NULL)) { |
4116 | goto resetandabort; |
4117 | } |
4118 | } |
4119 | #endif |
4120 | else { |
4121 | goto resetandabort; |
4122 | } |
4123 | |
4124 | if (inp) |
4125 | tp = intotcpcb(inp); |
4126 | #ifdef INET6 |
4127 | else if (in6p) |
4128 | tp = in6totcpcb(in6p); |
4129 | #endif |
4130 | else |
4131 | tp = NULL; |
4132 | tp->t_flags = sototcpcb(oso)->t_flags & TF_NODELAY; |
4133 | if (sc->sc_request_r_scale != 15) { |
4134 | tp->requested_s_scale = sc->sc_requested_s_scale; |
4135 | tp->request_r_scale = sc->sc_request_r_scale; |
4136 | tp->snd_scale = sc->sc_requested_s_scale; |
4137 | tp->rcv_scale = sc->sc_request_r_scale; |
4138 | tp->t_flags |= TF_REQ_SCALE|TF_RCVD_SCALE; |
4139 | } |
4140 | if (sc->sc_flags & SCF_TIMESTAMP) |
4141 | tp->t_flags |= TF_REQ_TSTMP|TF_RCVD_TSTMP; |
4142 | tp->ts_timebase = sc->sc_timebase; |
4143 | |
4144 | tp->t_template = tcp_template(tp); |
4145 | if (tp->t_template == 0) { |
4146 | tp = tcp_drop(tp, ENOBUFS); /* destroys socket */ |
4147 | so = NULL; |
4148 | m_freem(m); |
4149 | goto abort; |
4150 | } |
4151 | |
4152 | tp->iss = sc->sc_iss; |
4153 | tp->irs = sc->sc_irs; |
4154 | tcp_sendseqinit(tp); |
4155 | tcp_rcvseqinit(tp); |
4156 | tp->t_state = TCPS_SYN_RECEIVED; |
4157 | TCP_TIMER_ARM(tp, TCPT_KEEP, tp->t_keepinit); |
4158 | TCP_STATINC(TCP_STAT_ACCEPTS); |
4159 | |
4160 | if ((sc->sc_flags & SCF_SACK_PERMIT) && tcp_do_sack) |
4161 | tp->t_flags |= TF_WILL_SACK; |
4162 | |
4163 | if ((sc->sc_flags & SCF_ECN_PERMIT) && tcp_do_ecn) |
4164 | tp->t_flags |= TF_ECN_PERMIT; |
4165 | |
4166 | #ifdef TCP_SIGNATURE |
4167 | if (sc->sc_flags & SCF_SIGNATURE) |
4168 | tp->t_flags |= TF_SIGNATURE; |
4169 | #endif |
4170 | |
4171 | /* Initialize tp->t_ourmss before we deal with the peer's! */ |
4172 | tp->t_ourmss = sc->sc_ourmaxseg; |
4173 | tcp_mss_from_peer(tp, sc->sc_peermaxseg); |
4174 | |
4175 | /* |
4176 | * Initialize the initial congestion window. If we |
4177 | * had to retransmit the SYN,ACK, we must initialize cwnd |
4178 | * to 1 segment (i.e. the Loss Window). |
4179 | */ |
4180 | if (sc->sc_rxtshift) |
4181 | tp->snd_cwnd = tp->t_peermss; |
4182 | else { |
4183 | int ss = tcp_init_win; |
4184 | #ifdef INET |
4185 | if (inp != NULL && in_localaddr(inp->inp_faddr)) |
4186 | ss = tcp_init_win_local; |
4187 | #endif |
4188 | #ifdef INET6 |
4189 | if (in6p != NULL && in6_localaddr(&in6p->in6p_faddr)) |
4190 | ss = tcp_init_win_local; |
4191 | #endif |
4192 | tp->snd_cwnd = TCP_INITIAL_WINDOW(ss, tp->t_peermss); |
4193 | } |
4194 | |
4195 | tcp_rmx_rtt(tp); |
4196 | tp->snd_wl1 = sc->sc_irs; |
4197 | tp->rcv_up = sc->sc_irs + 1; |
4198 | |
4199 | /* |
4200 | * This is what whould have happened in tcp_output() when |
4201 | * the SYN,ACK was sent. |
4202 | */ |
4203 | tp->snd_up = tp->snd_una; |
4204 | tp->snd_max = tp->snd_nxt = tp->iss+1; |
4205 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
4206 | if (sc->sc_win > 0 && SEQ_GT(tp->rcv_nxt + sc->sc_win, tp->rcv_adv)) |
4207 | tp->rcv_adv = tp->rcv_nxt + sc->sc_win; |
4208 | tp->last_ack_sent = tp->rcv_nxt; |
4209 | tp->t_partialacks = -1; |
4210 | tp->t_dupacks = 0; |
4211 | |
4212 | TCP_STATINC(TCP_STAT_SC_COMPLETED); |
4213 | s = splsoftnet(); |
4214 | syn_cache_put(sc); |
4215 | splx(s); |
4216 | return (so); |
4217 | |
4218 | resetandabort: |
4219 | (void)tcp_respond(NULL, m, m, th, (tcp_seq)0, th->th_ack, TH_RST); |
4220 | abort: |
4221 | if (so != NULL) { |
4222 | (void) soqremque(so, 1); |
4223 | (void) soabort(so); |
4224 | mutex_enter(softnet_lock); |
4225 | } |
4226 | s = splsoftnet(); |
4227 | syn_cache_put(sc); |
4228 | splx(s); |
4229 | TCP_STATINC(TCP_STAT_SC_ABORTED); |
4230 | return ((struct socket *)(-1)); |
4231 | } |
4232 | |
4233 | /* |
4234 | * This function is called when we get a RST for a |
4235 | * non-existent connection, so that we can see if the |
4236 | * connection is in the syn cache. If it is, zap it. |
4237 | */ |
4238 | |
4239 | void |
4240 | syn_cache_reset(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th) |
4241 | { |
4242 | struct syn_cache *sc; |
4243 | struct syn_cache_head *scp; |
4244 | int s = splsoftnet(); |
4245 | |
4246 | if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { |
4247 | splx(s); |
4248 | return; |
4249 | } |
4250 | if (SEQ_LT(th->th_seq, sc->sc_irs) || |
4251 | SEQ_GT(th->th_seq, sc->sc_irs+1)) { |
4252 | splx(s); |
4253 | return; |
4254 | } |
4255 | syn_cache_rm(sc); |
4256 | TCP_STATINC(TCP_STAT_SC_RESET); |
4257 | syn_cache_put(sc); /* calls pool_put but see spl above */ |
4258 | splx(s); |
4259 | } |
4260 | |
4261 | void |
4262 | syn_cache_unreach(const struct sockaddr *src, const struct sockaddr *dst, |
4263 | struct tcphdr *th) |
4264 | { |
4265 | struct syn_cache *sc; |
4266 | struct syn_cache_head *scp; |
4267 | int s; |
4268 | |
4269 | s = splsoftnet(); |
4270 | if ((sc = syn_cache_lookup(src, dst, &scp)) == NULL) { |
4271 | splx(s); |
4272 | return; |
4273 | } |
4274 | /* If the sequence number != sc_iss, then it's a bogus ICMP msg */ |
4275 | if (ntohl (th->th_seq) != sc->sc_iss) { |
4276 | splx(s); |
4277 | return; |
4278 | } |
4279 | |
4280 | /* |
4281 | * If we've retransmitted 3 times and this is our second error, |
4282 | * we remove the entry. Otherwise, we allow it to continue on. |
4283 | * This prevents us from incorrectly nuking an entry during a |
4284 | * spurious network outage. |
4285 | * |
4286 | * See tcp_notify(). |
4287 | */ |
4288 | if ((sc->sc_flags & SCF_UNREACH) == 0 || sc->sc_rxtshift < 3) { |
4289 | sc->sc_flags |= SCF_UNREACH; |
4290 | splx(s); |
4291 | return; |
4292 | } |
4293 | |
4294 | syn_cache_rm(sc); |
4295 | TCP_STATINC(TCP_STAT_SC_UNREACH); |
4296 | syn_cache_put(sc); /* calls pool_put but see spl above */ |
4297 | splx(s); |
4298 | } |
4299 | |
4300 | /* |
4301 | * Given a LISTEN socket and an inbound SYN request, add |
4302 | * this to the syn cache, and send back a segment: |
4303 | * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> |
4304 | * to the source. |
4305 | * |
4306 | * IMPORTANT NOTE: We do _NOT_ ACK data that might accompany the SYN. |
4307 | * Doing so would require that we hold onto the data and deliver it |
4308 | * to the application. However, if we are the target of a SYN-flood |
4309 | * DoS attack, an attacker could send data which would eventually |
4310 | * consume all available buffer space if it were ACKed. By not ACKing |
4311 | * the data, we avoid this DoS scenario. |
4312 | */ |
4313 | |
4314 | int |
4315 | syn_cache_add(struct sockaddr *src, struct sockaddr *dst, struct tcphdr *th, |
4316 | unsigned int hlen, struct socket *so, struct mbuf *m, u_char *optp, |
4317 | int optlen, struct tcp_opt_info *oi) |
4318 | { |
4319 | struct tcpcb tb, *tp; |
4320 | long win; |
4321 | struct syn_cache *sc; |
4322 | struct syn_cache_head *scp; |
4323 | struct mbuf *ipopts; |
4324 | struct tcp_opt_info opti; |
4325 | int s; |
4326 | |
4327 | tp = sototcpcb(so); |
4328 | |
4329 | memset(&opti, 0, sizeof(opti)); |
4330 | |
4331 | /* |
4332 | * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN |
4333 | * |
4334 | * Note this check is performed in tcp_input() very early on. |
4335 | */ |
4336 | |
4337 | /* |
4338 | * Initialize some local state. |
4339 | */ |
4340 | win = sbspace(&so->so_rcv); |
4341 | if (win > TCP_MAXWIN) |
4342 | win = TCP_MAXWIN; |
4343 | |
4344 | switch (src->sa_family) { |
4345 | #ifdef INET |
4346 | case AF_INET: |
4347 | /* |
4348 | * Remember the IP options, if any. |
4349 | */ |
4350 | ipopts = ip_srcroute(); |
4351 | break; |
4352 | #endif |
4353 | default: |
4354 | ipopts = NULL; |
4355 | } |
4356 | |
4357 | #ifdef TCP_SIGNATURE |
4358 | if (optp || (tp->t_flags & TF_SIGNATURE)) |
4359 | #else |
4360 | if (optp) |
4361 | #endif |
4362 | { |
4363 | tb.t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0; |
4364 | #ifdef TCP_SIGNATURE |
4365 | tb.t_flags |= (tp->t_flags & TF_SIGNATURE); |
4366 | #endif |
4367 | tb.t_state = TCPS_LISTEN; |
4368 | if (tcp_dooptions(&tb, optp, optlen, th, m, m->m_pkthdr.len - |
4369 | sizeof(struct tcphdr) - optlen - hlen, oi) < 0) |
4370 | return (0); |
4371 | } else |
4372 | tb.t_flags = 0; |
4373 | |
4374 | /* |
4375 | * See if we already have an entry for this connection. |
4376 | * If we do, resend the SYN,ACK. We do not count this |
4377 | * as a retransmission (XXX though maybe we should). |
4378 | */ |
4379 | if ((sc = syn_cache_lookup(src, dst, &scp)) != NULL) { |
4380 | TCP_STATINC(TCP_STAT_SC_DUPESYN); |
4381 | if (ipopts) { |
4382 | /* |
4383 | * If we were remembering a previous source route, |
4384 | * forget it and use the new one we've been given. |
4385 | */ |
4386 | if (sc->sc_ipopts) |
4387 | (void) m_free(sc->sc_ipopts); |
4388 | sc->sc_ipopts = ipopts; |
4389 | } |
4390 | sc->sc_timestamp = tb.ts_recent; |
4391 | if (syn_cache_respond(sc, m) == 0) { |
4392 | uint64_t *tcps = TCP_STAT_GETREF(); |
4393 | tcps[TCP_STAT_SNDACKS]++; |
4394 | tcps[TCP_STAT_SNDTOTAL]++; |
4395 | TCP_STAT_PUTREF(); |
4396 | } |
4397 | return (1); |
4398 | } |
4399 | |
4400 | s = splsoftnet(); |
4401 | sc = pool_get(&syn_cache_pool, PR_NOWAIT); |
4402 | splx(s); |
4403 | if (sc == NULL) { |
4404 | if (ipopts) |
4405 | (void) m_free(ipopts); |
4406 | return (0); |
4407 | } |
4408 | |
4409 | /* |
4410 | * Fill in the cache, and put the necessary IP and TCP |
4411 | * options into the reply. |
4412 | */ |
4413 | memset(sc, 0, sizeof(struct syn_cache)); |
4414 | callout_init(&sc->sc_timer, CALLOUT_MPSAFE); |
4415 | bcopy(src, &sc->sc_src, src->sa_len); |
4416 | bcopy(dst, &sc->sc_dst, dst->sa_len); |
4417 | sc->sc_flags = 0; |
4418 | sc->sc_ipopts = ipopts; |
4419 | sc->sc_irs = th->th_seq; |
4420 | switch (src->sa_family) { |
4421 | #ifdef INET |
4422 | case AF_INET: |
4423 | { |
4424 | struct sockaddr_in *srcin = (void *) src; |
4425 | struct sockaddr_in *dstin = (void *) dst; |
4426 | |
4427 | sc->sc_iss = tcp_new_iss1(&dstin->sin_addr, |
4428 | &srcin->sin_addr, dstin->sin_port, |
4429 | srcin->sin_port, sizeof(dstin->sin_addr), 0); |
4430 | break; |
4431 | } |
4432 | #endif /* INET */ |
4433 | #ifdef INET6 |
4434 | case AF_INET6: |
4435 | { |
4436 | struct sockaddr_in6 *srcin6 = (void *) src; |
4437 | struct sockaddr_in6 *dstin6 = (void *) dst; |
4438 | |
4439 | sc->sc_iss = tcp_new_iss1(&dstin6->sin6_addr, |
4440 | &srcin6->sin6_addr, dstin6->sin6_port, |
4441 | srcin6->sin6_port, sizeof(dstin6->sin6_addr), 0); |
4442 | break; |
4443 | } |
4444 | #endif /* INET6 */ |
4445 | } |
4446 | sc->sc_peermaxseg = oi->maxseg; |
4447 | sc->sc_ourmaxseg = tcp_mss_to_advertise(m->m_flags & M_PKTHDR ? |
4448 | m_get_rcvif_NOMPSAFE(m) : NULL, |
4449 | sc->sc_src.sa.sa_family); |
4450 | sc->sc_win = win; |
4451 | sc->sc_timebase = tcp_now - 1; /* see tcp_newtcpcb() */ |
4452 | sc->sc_timestamp = tb.ts_recent; |
4453 | if ((tb.t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP)) == |
4454 | (TF_REQ_TSTMP|TF_RCVD_TSTMP)) |
4455 | sc->sc_flags |= SCF_TIMESTAMP; |
4456 | if ((tb.t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) == |
4457 | (TF_RCVD_SCALE|TF_REQ_SCALE)) { |
4458 | sc->sc_requested_s_scale = tb.requested_s_scale; |
4459 | sc->sc_request_r_scale = 0; |
4460 | /* |
4461 | * Pick the smallest possible scaling factor that |
4462 | * will still allow us to scale up to sb_max. |
4463 | * |
4464 | * We do this because there are broken firewalls that |
4465 | * will corrupt the window scale option, leading to |
4466 | * the other endpoint believing that our advertised |
4467 | * window is unscaled. At scale factors larger than |
4468 | * 5 the unscaled window will drop below 1500 bytes, |
4469 | * leading to serious problems when traversing these |
4470 | * broken firewalls. |
4471 | * |
4472 | * With the default sbmax of 256K, a scale factor |
4473 | * of 3 will be chosen by this algorithm. Those who |
4474 | * choose a larger sbmax should watch out |
4475 | * for the compatiblity problems mentioned above. |
4476 | * |
4477 | * RFC1323: The Window field in a SYN (i.e., a <SYN> |
4478 | * or <SYN,ACK>) segment itself is never scaled. |
4479 | */ |
4480 | while (sc->sc_request_r_scale < TCP_MAX_WINSHIFT && |
4481 | (TCP_MAXWIN << sc->sc_request_r_scale) < sb_max) |
4482 | sc->sc_request_r_scale++; |
4483 | } else { |
4484 | sc->sc_requested_s_scale = 15; |
4485 | sc->sc_request_r_scale = 15; |
4486 | } |
4487 | if ((tb.t_flags & TF_SACK_PERMIT) && tcp_do_sack) |
4488 | sc->sc_flags |= SCF_SACK_PERMIT; |
4489 | |
4490 | /* |
4491 | * ECN setup packet recieved. |
4492 | */ |
4493 | if ((th->th_flags & (TH_ECE|TH_CWR)) && tcp_do_ecn) |
4494 | sc->sc_flags |= SCF_ECN_PERMIT; |
4495 | |
4496 | #ifdef TCP_SIGNATURE |
4497 | if (tb.t_flags & TF_SIGNATURE) |
4498 | sc->sc_flags |= SCF_SIGNATURE; |
4499 | #endif |
4500 | sc->sc_tp = tp; |
4501 | if (syn_cache_respond(sc, m) == 0) { |
4502 | uint64_t *tcps = TCP_STAT_GETREF(); |
4503 | tcps[TCP_STAT_SNDACKS]++; |
4504 | tcps[TCP_STAT_SNDTOTAL]++; |
4505 | TCP_STAT_PUTREF(); |
4506 | syn_cache_insert(sc, tp); |
4507 | } else { |
4508 | s = splsoftnet(); |
4509 | /* |
4510 | * syn_cache_put() will try to schedule the timer, so |
4511 | * we need to initialize it |
4512 | */ |
4513 | SYN_CACHE_TIMER_ARM(sc); |
4514 | syn_cache_put(sc); |
4515 | splx(s); |
4516 | TCP_STATINC(TCP_STAT_SC_DROPPED); |
4517 | } |
4518 | return (1); |
4519 | } |
4520 | |
4521 | /* |
4522 | * syn_cache_respond: (re)send SYN+ACK. |
4523 | * |
4524 | * returns 0 on success. otherwise returns an errno, typically ENOBUFS. |
4525 | */ |
4526 | |
4527 | int |
4528 | syn_cache_respond(struct syn_cache *sc, struct mbuf *m) |
4529 | { |
4530 | #ifdef INET6 |
4531 | struct rtentry *rt; |
4532 | #endif |
4533 | struct route *ro; |
4534 | u_int8_t *optp; |
4535 | int optlen, error; |
4536 | u_int16_t tlen; |
4537 | struct ip *ip = NULL; |
4538 | #ifdef INET6 |
4539 | struct ip6_hdr *ip6 = NULL; |
4540 | #endif |
4541 | struct tcpcb *tp = NULL; |
4542 | struct tcphdr *th; |
4543 | u_int hlen; |
4544 | struct socket *so; |
4545 | |
4546 | ro = &sc->sc_route; |
4547 | switch (sc->sc_src.sa.sa_family) { |
4548 | case AF_INET: |
4549 | hlen = sizeof(struct ip); |
4550 | break; |
4551 | #ifdef INET6 |
4552 | case AF_INET6: |
4553 | hlen = sizeof(struct ip6_hdr); |
4554 | break; |
4555 | #endif |
4556 | default: |
4557 | if (m) |
4558 | m_freem(m); |
4559 | return (EAFNOSUPPORT); |
4560 | } |
4561 | |
4562 | /* Compute the size of the TCP options. */ |
4563 | optlen = 4 + (sc->sc_request_r_scale != 15 ? 4 : 0) + |
4564 | ((sc->sc_flags & SCF_SACK_PERMIT) ? (TCPOLEN_SACK_PERMITTED + 2) : 0) + |
4565 | #ifdef TCP_SIGNATURE |
4566 | ((sc->sc_flags & SCF_SIGNATURE) ? (TCPOLEN_SIGNATURE + 2) : 0) + |
4567 | #endif |
4568 | ((sc->sc_flags & SCF_TIMESTAMP) ? TCPOLEN_TSTAMP_APPA : 0); |
4569 | |
4570 | tlen = hlen + sizeof(struct tcphdr) + optlen; |
4571 | |
4572 | /* |
4573 | * Create the IP+TCP header from scratch. |
4574 | */ |
4575 | if (m) |
4576 | m_freem(m); |
4577 | #ifdef DIAGNOSTIC |
4578 | if (max_linkhdr + tlen > MCLBYTES) |
4579 | return (ENOBUFS); |
4580 | #endif |
4581 | MGETHDR(m, M_DONTWAIT, MT_DATA); |
4582 | if (m && (max_linkhdr + tlen) > MHLEN) { |
4583 | MCLGET(m, M_DONTWAIT); |
4584 | if ((m->m_flags & M_EXT) == 0) { |
4585 | m_freem(m); |
4586 | m = NULL; |
4587 | } |
4588 | } |
4589 | if (m == NULL) |
4590 | return (ENOBUFS); |
4591 | MCLAIM(m, &tcp_tx_mowner); |
4592 | |
4593 | /* Fixup the mbuf. */ |
4594 | m->m_data += max_linkhdr; |
4595 | m->m_len = m->m_pkthdr.len = tlen; |
4596 | if (sc->sc_tp) { |
4597 | tp = sc->sc_tp; |
4598 | if (tp->t_inpcb) |
4599 | so = tp->t_inpcb->inp_socket; |
4600 | #ifdef INET6 |
4601 | else if (tp->t_in6pcb) |
4602 | so = tp->t_in6pcb->in6p_socket; |
4603 | #endif |
4604 | else |
4605 | so = NULL; |
4606 | } else |
4607 | so = NULL; |
4608 | m_reset_rcvif(m); |
4609 | memset(mtod(m, u_char *), 0, tlen); |
4610 | |
4611 | switch (sc->sc_src.sa.sa_family) { |
4612 | case AF_INET: |
4613 | ip = mtod(m, struct ip *); |
4614 | ip->ip_v = 4; |
4615 | ip->ip_dst = sc->sc_src.sin.sin_addr; |
4616 | ip->ip_src = sc->sc_dst.sin.sin_addr; |
4617 | ip->ip_p = IPPROTO_TCP; |
4618 | th = (struct tcphdr *)(ip + 1); |
4619 | th->th_dport = sc->sc_src.sin.sin_port; |
4620 | th->th_sport = sc->sc_dst.sin.sin_port; |
4621 | break; |
4622 | #ifdef INET6 |
4623 | case AF_INET6: |
4624 | ip6 = mtod(m, struct ip6_hdr *); |
4625 | ip6->ip6_vfc = IPV6_VERSION; |
4626 | ip6->ip6_dst = sc->sc_src.sin6.sin6_addr; |
4627 | ip6->ip6_src = sc->sc_dst.sin6.sin6_addr; |
4628 | ip6->ip6_nxt = IPPROTO_TCP; |
4629 | /* ip6_plen will be updated in ip6_output() */ |
4630 | th = (struct tcphdr *)(ip6 + 1); |
4631 | th->th_dport = sc->sc_src.sin6.sin6_port; |
4632 | th->th_sport = sc->sc_dst.sin6.sin6_port; |
4633 | break; |
4634 | #endif |
4635 | default: |
4636 | th = NULL; |
4637 | } |
4638 | |
4639 | th->th_seq = htonl(sc->sc_iss); |
4640 | th->th_ack = htonl(sc->sc_irs + 1); |
4641 | th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; |
4642 | th->th_flags = TH_SYN|TH_ACK; |
4643 | th->th_win = htons(sc->sc_win); |
4644 | /* th_sum already 0 */ |
4645 | /* th_urp already 0 */ |
4646 | |
4647 | /* Tack on the TCP options. */ |
4648 | optp = (u_int8_t *)(th + 1); |
4649 | *optp++ = TCPOPT_MAXSEG; |
4650 | *optp++ = 4; |
4651 | *optp++ = (sc->sc_ourmaxseg >> 8) & 0xff; |
4652 | *optp++ = sc->sc_ourmaxseg & 0xff; |
4653 | |
4654 | if (sc->sc_request_r_scale != 15) { |
4655 | *((u_int32_t *)optp) = htonl(TCPOPT_NOP << 24 | |
4656 | TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 | |
4657 | sc->sc_request_r_scale); |
4658 | optp += 4; |
4659 | } |
4660 | |
4661 | if (sc->sc_flags & SCF_TIMESTAMP) { |
4662 | u_int32_t *lp = (u_int32_t *)(optp); |
4663 | /* Form timestamp option as shown in appendix A of RFC 1323. */ |
4664 | *lp++ = htonl(TCPOPT_TSTAMP_HDR); |
4665 | *lp++ = htonl(SYN_CACHE_TIMESTAMP(sc)); |
4666 | *lp = htonl(sc->sc_timestamp); |
4667 | optp += TCPOLEN_TSTAMP_APPA; |
4668 | } |
4669 | |
4670 | if (sc->sc_flags & SCF_SACK_PERMIT) { |
4671 | u_int8_t *p = optp; |
4672 | |
4673 | /* Let the peer know that we will SACK. */ |
4674 | p[0] = TCPOPT_SACK_PERMITTED; |
4675 | p[1] = 2; |
4676 | p[2] = TCPOPT_NOP; |
4677 | p[3] = TCPOPT_NOP; |
4678 | optp += 4; |
4679 | } |
4680 | |
4681 | /* |
4682 | * Send ECN SYN-ACK setup packet. |
4683 | * Routes can be asymetric, so, even if we receive a packet |
4684 | * with ECE and CWR set, we must not assume no one will block |
4685 | * the ECE packet we are about to send. |
4686 | */ |
4687 | if ((sc->sc_flags & SCF_ECN_PERMIT) && tp && |
4688 | SEQ_GEQ(tp->snd_nxt, tp->snd_max)) { |
4689 | th->th_flags |= TH_ECE; |
4690 | TCP_STATINC(TCP_STAT_ECN_SHS); |
4691 | |
4692 | /* |
4693 | * draft-ietf-tcpm-ecnsyn-00.txt |
4694 | * |
4695 | * "[...] a TCP node MAY respond to an ECN-setup |
4696 | * SYN packet by setting ECT in the responding |
4697 | * ECN-setup SYN/ACK packet, indicating to routers |
4698 | * that the SYN/ACK packet is ECN-Capable. |
4699 | * This allows a congested router along the path |
4700 | * to mark the packet instead of dropping the |
4701 | * packet as an indication of congestion." |
4702 | * |
4703 | * "[...] There can be a great benefit in setting |
4704 | * an ECN-capable codepoint in SYN/ACK packets [...] |
4705 | * Congestion is most likely to occur in |
4706 | * the server-to-client direction. As a result, |
4707 | * setting an ECN-capable codepoint in SYN/ACK |
4708 | * packets can reduce the occurence of three-second |
4709 | * retransmit timeouts resulting from the drop |
4710 | * of SYN/ACK packets." |
4711 | * |
4712 | * Page 4 and 6, January 2006. |
4713 | */ |
4714 | |
4715 | switch (sc->sc_src.sa.sa_family) { |
4716 | #ifdef INET |
4717 | case AF_INET: |
4718 | ip->ip_tos |= IPTOS_ECN_ECT0; |
4719 | break; |
4720 | #endif |
4721 | #ifdef INET6 |
4722 | case AF_INET6: |
4723 | ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); |
4724 | break; |
4725 | #endif |
4726 | } |
4727 | TCP_STATINC(TCP_STAT_ECN_ECT); |
4728 | } |
4729 | |
4730 | #ifdef TCP_SIGNATURE |
4731 | if (sc->sc_flags & SCF_SIGNATURE) { |
4732 | struct secasvar *sav; |
4733 | u_int8_t *sigp; |
4734 | |
4735 | sav = tcp_signature_getsav(m, th); |
4736 | |
4737 | if (sav == NULL) { |
4738 | if (m) |
4739 | m_freem(m); |
4740 | return (EPERM); |
4741 | } |
4742 | |
4743 | *optp++ = TCPOPT_SIGNATURE; |
4744 | *optp++ = TCPOLEN_SIGNATURE; |
4745 | sigp = optp; |
4746 | memset(optp, 0, TCP_SIGLEN); |
4747 | optp += TCP_SIGLEN; |
4748 | *optp++ = TCPOPT_NOP; |
4749 | *optp++ = TCPOPT_EOL; |
4750 | |
4751 | (void)tcp_signature(m, th, hlen, sav, sigp); |
4752 | |
4753 | key_sa_recordxfer(sav, m); |
4754 | KEY_FREESAV(&sav); |
4755 | } |
4756 | #endif |
4757 | |
4758 | /* Compute the packet's checksum. */ |
4759 | switch (sc->sc_src.sa.sa_family) { |
4760 | case AF_INET: |
4761 | ip->ip_len = htons(tlen - hlen); |
4762 | th->th_sum = 0; |
4763 | th->th_sum = in4_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); |
4764 | break; |
4765 | #ifdef INET6 |
4766 | case AF_INET6: |
4767 | ip6->ip6_plen = htons(tlen - hlen); |
4768 | th->th_sum = 0; |
4769 | th->th_sum = in6_cksum(m, IPPROTO_TCP, hlen, tlen - hlen); |
4770 | break; |
4771 | #endif |
4772 | } |
4773 | |
4774 | /* |
4775 | * Fill in some straggling IP bits. Note the stack expects |
4776 | * ip_len to be in host order, for convenience. |
4777 | */ |
4778 | switch (sc->sc_src.sa.sa_family) { |
4779 | #ifdef INET |
4780 | case AF_INET: |
4781 | ip->ip_len = htons(tlen); |
4782 | ip->ip_ttl = ip_defttl; |
4783 | /* XXX tos? */ |
4784 | break; |
4785 | #endif |
4786 | #ifdef INET6 |
4787 | case AF_INET6: |
4788 | ip6->ip6_vfc &= ~IPV6_VERSION_MASK; |
4789 | ip6->ip6_vfc |= IPV6_VERSION; |
4790 | ip6->ip6_plen = htons(tlen - hlen); |
4791 | /* ip6_hlim will be initialized afterwards */ |
4792 | /* XXX flowlabel? */ |
4793 | break; |
4794 | #endif |
4795 | } |
4796 | |
4797 | /* XXX use IPsec policy on listening socket, on SYN ACK */ |
4798 | tp = sc->sc_tp; |
4799 | |
4800 | switch (sc->sc_src.sa.sa_family) { |
4801 | #ifdef INET |
4802 | case AF_INET: |
4803 | error = ip_output(m, sc->sc_ipopts, ro, |
4804 | (ip_mtudisc ? IP_MTUDISC : 0), |
4805 | NULL, so); |
4806 | break; |
4807 | #endif |
4808 | #ifdef INET6 |
4809 | case AF_INET6: |
4810 | ip6->ip6_hlim = in6_selecthlim(NULL, |
4811 | (rt = rtcache_validate(ro)) != NULL ? rt->rt_ifp : NULL); |
4812 | |
4813 | error = ip6_output(m, NULL /*XXX*/, ro, 0, NULL, so, NULL); |
4814 | break; |
4815 | #endif |
4816 | default: |
4817 | error = EAFNOSUPPORT; |
4818 | break; |
4819 | } |
4820 | return (error); |
4821 | } |
4822 | |