1 | /* $NetBSD: tcp_output.c,v 1.186 2016/06/10 13:27:16 ozaki-r 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, 2001, 2005, 2006 The NetBSD Foundation, Inc. |
74 | * All rights reserved. |
75 | * |
76 | * This code is derived from software contributed to The NetBSD Foundation |
77 | * by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation |
78 | * Facility, NASA Ames Research Center. |
79 | * This code is derived from software contributed to The NetBSD Foundation |
80 | * by Charles M. Hannum. |
81 | * This code is derived from software contributed to The NetBSD Foundation |
82 | * by Rui Paulo. |
83 | * |
84 | * Redistribution and use in source and binary forms, with or without |
85 | * modification, are permitted provided that the following conditions |
86 | * are met: |
87 | * 1. Redistributions of source code must retain the above copyright |
88 | * notice, this list of conditions and the following disclaimer. |
89 | * 2. Redistributions in binary form must reproduce the above copyright |
90 | * notice, this list of conditions and the following disclaimer in the |
91 | * documentation and/or other materials provided with the distribution. |
92 | * |
93 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
94 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
95 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
96 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
97 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
98 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
99 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
100 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
101 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
102 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
103 | * POSSIBILITY OF SUCH DAMAGE. |
104 | */ |
105 | |
106 | /* |
107 | * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 |
108 | * The Regents of the University of California. All rights reserved. |
109 | * |
110 | * Redistribution and use in source and binary forms, with or without |
111 | * modification, are permitted provided that the following conditions |
112 | * are met: |
113 | * 1. Redistributions of source code must retain the above copyright |
114 | * notice, this list of conditions and the following disclaimer. |
115 | * 2. Redistributions in binary form must reproduce the above copyright |
116 | * notice, this list of conditions and the following disclaimer in the |
117 | * documentation and/or other materials provided with the distribution. |
118 | * 3. Neither the name of the University nor the names of its contributors |
119 | * may be used to endorse or promote products derived from this software |
120 | * without specific prior written permission. |
121 | * |
122 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
123 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
124 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
125 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
126 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
127 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
128 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
129 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
130 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
131 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
132 | * SUCH DAMAGE. |
133 | * |
134 | * @(#)tcp_output.c 8.4 (Berkeley) 5/24/95 |
135 | */ |
136 | |
137 | #include <sys/cdefs.h> |
138 | __KERNEL_RCSID(0, "$NetBSD: tcp_output.c,v 1.186 2016/06/10 13:27:16 ozaki-r Exp $" ); |
139 | |
140 | #ifdef _KERNEL_OPT |
141 | #include "opt_inet.h" |
142 | #include "opt_ipsec.h" |
143 | #include "opt_tcp_debug.h" |
144 | #endif |
145 | |
146 | #include <sys/param.h> |
147 | #include <sys/systm.h> |
148 | #include <sys/mbuf.h> |
149 | #include <sys/protosw.h> |
150 | #include <sys/socket.h> |
151 | #include <sys/socketvar.h> |
152 | #include <sys/errno.h> |
153 | #include <sys/domain.h> |
154 | #include <sys/kernel.h> |
155 | #ifdef TCP_SIGNATURE |
156 | #include <sys/md5.h> |
157 | #endif |
158 | |
159 | #include <net/if.h> |
160 | #include <net/route.h> |
161 | |
162 | #include <netinet/in.h> |
163 | #include <netinet/in_systm.h> |
164 | #include <netinet/ip.h> |
165 | #include <netinet/in_pcb.h> |
166 | #include <netinet/ip_var.h> |
167 | |
168 | #ifdef INET6 |
169 | #ifndef INET |
170 | #include <netinet/in.h> |
171 | #endif |
172 | #include <netinet/ip6.h> |
173 | #include <netinet6/in6_var.h> |
174 | #include <netinet6/ip6_var.h> |
175 | #include <netinet6/in6_pcb.h> |
176 | #include <netinet6/nd6.h> |
177 | #endif |
178 | |
179 | #ifdef IPSEC |
180 | #include <netipsec/ipsec.h> |
181 | #include <netipsec/key.h> |
182 | #ifdef INET6 |
183 | #include <netipsec/ipsec6.h> |
184 | #endif |
185 | #endif /* IPSEC*/ |
186 | |
187 | #include <netinet/tcp.h> |
188 | #define TCPOUTFLAGS |
189 | #include <netinet/tcp_fsm.h> |
190 | #include <netinet/tcp_seq.h> |
191 | #include <netinet/tcp_timer.h> |
192 | #include <netinet/tcp_var.h> |
193 | #include <netinet/tcp_private.h> |
194 | #include <netinet/tcp_congctl.h> |
195 | #include <netinet/tcpip.h> |
196 | #include <netinet/tcp_debug.h> |
197 | #include <netinet/in_offload.h> |
198 | #include <netinet6/in6_offload.h> |
199 | |
200 | #ifdef notyet |
201 | extern struct mbuf *m_copypack(); |
202 | #endif |
203 | |
204 | /* |
205 | * Knob to enable Congestion Window Monitoring, and control |
206 | * the burst size it allows. Default burst is 4 packets, per |
207 | * the Internet draft. |
208 | */ |
209 | int tcp_cwm = 0; |
210 | int tcp_cwm_burstsize = 4; |
211 | |
212 | int tcp_do_autosndbuf = 1; |
213 | int tcp_autosndbuf_inc = 8 * 1024; |
214 | int tcp_autosndbuf_max = 256 * 1024; |
215 | |
216 | #ifdef TCP_OUTPUT_COUNTERS |
217 | #include <sys/device.h> |
218 | |
219 | extern struct evcnt tcp_output_bigheader; |
220 | extern struct evcnt tcp_output_predict_hit; |
221 | extern struct evcnt tcp_output_predict_miss; |
222 | extern struct evcnt tcp_output_copysmall; |
223 | extern struct evcnt tcp_output_copybig; |
224 | extern struct evcnt tcp_output_refbig; |
225 | |
226 | #define TCP_OUTPUT_COUNTER_INCR(ev) (ev)->ev_count++ |
227 | #else |
228 | |
229 | #define TCP_OUTPUT_COUNTER_INCR(ev) /* nothing */ |
230 | |
231 | #endif /* TCP_OUTPUT_COUNTERS */ |
232 | |
233 | static |
234 | #ifndef GPROF |
235 | inline |
236 | #endif |
237 | int |
238 | tcp_segsize(struct tcpcb *tp, int *txsegsizep, int *rxsegsizep, |
239 | bool *alwaysfragp) |
240 | { |
241 | #ifdef INET |
242 | struct inpcb *inp = tp->t_inpcb; |
243 | #endif |
244 | #ifdef INET6 |
245 | struct in6pcb *in6p = tp->t_in6pcb; |
246 | #endif |
247 | struct socket *so = NULL; |
248 | struct rtentry *rt; |
249 | struct ifnet *ifp; |
250 | int size; |
251 | int hdrlen; |
252 | int optlen; |
253 | |
254 | *alwaysfragp = false; |
255 | |
256 | #ifdef DIAGNOSTIC |
257 | if (tp->t_inpcb && tp->t_in6pcb) |
258 | panic("tcp_segsize: both t_inpcb and t_in6pcb are set" ); |
259 | #endif |
260 | switch (tp->t_family) { |
261 | #ifdef INET |
262 | case AF_INET: |
263 | hdrlen = sizeof(struct ip) + sizeof(struct tcphdr); |
264 | break; |
265 | #endif |
266 | #ifdef INET6 |
267 | case AF_INET6: |
268 | hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); |
269 | break; |
270 | #endif |
271 | default: |
272 | size = tcp_mssdflt; |
273 | goto out; |
274 | } |
275 | |
276 | rt = NULL; |
277 | #ifdef INET |
278 | if (inp) { |
279 | rt = in_pcbrtentry(inp); |
280 | so = inp->inp_socket; |
281 | } |
282 | #endif |
283 | #ifdef INET6 |
284 | if (in6p) { |
285 | rt = in6_pcbrtentry(in6p); |
286 | so = in6p->in6p_socket; |
287 | } |
288 | #endif |
289 | if (rt == NULL) { |
290 | size = tcp_mssdflt; |
291 | goto out; |
292 | } |
293 | |
294 | ifp = rt->rt_ifp; |
295 | |
296 | size = tcp_mssdflt; |
297 | if (tp->t_mtudisc && rt->rt_rmx.rmx_mtu != 0) { |
298 | #ifdef INET6 |
299 | if (in6p && rt->rt_rmx.rmx_mtu < IPV6_MMTU) { |
300 | /* |
301 | * RFC2460 section 5, last paragraph: if path MTU is |
302 | * smaller than 1280, use 1280 as packet size and |
303 | * attach fragment header. |
304 | */ |
305 | size = IPV6_MMTU - hdrlen - sizeof(struct ip6_frag); |
306 | *alwaysfragp = true; |
307 | } else |
308 | size = rt->rt_rmx.rmx_mtu - hdrlen; |
309 | #else |
310 | size = rt->rt_rmx.rmx_mtu - hdrlen; |
311 | #endif |
312 | } else if (ifp->if_flags & IFF_LOOPBACK) |
313 | size = ifp->if_mtu - hdrlen; |
314 | #ifdef INET |
315 | else if (inp && tp->t_mtudisc) |
316 | size = ifp->if_mtu - hdrlen; |
317 | else if (inp && in_localaddr(inp->inp_faddr)) |
318 | size = ifp->if_mtu - hdrlen; |
319 | #endif |
320 | #ifdef INET6 |
321 | else if (in6p) { |
322 | #ifdef INET |
323 | if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr)) { |
324 | /* mapped addr case */ |
325 | struct in_addr d; |
326 | bcopy(&in6p->in6p_faddr.s6_addr32[3], &d, sizeof(d)); |
327 | if (tp->t_mtudisc || in_localaddr(d)) |
328 | size = ifp->if_mtu - hdrlen; |
329 | } else |
330 | #endif |
331 | { |
332 | /* |
333 | * for IPv6, path MTU discovery is always turned on, |
334 | * or the node must use packet size <= 1280. |
335 | */ |
336 | size = tp->t_mtudisc ? IN6_LINKMTU(ifp) : IPV6_MMTU; |
337 | size -= hdrlen; |
338 | } |
339 | } |
340 | #endif |
341 | out: |
342 | /* |
343 | * Now we must make room for whatever extra TCP/IP options are in |
344 | * the packet. |
345 | */ |
346 | optlen = tcp_optlen(tp); |
347 | |
348 | /* |
349 | * XXX tp->t_ourmss should have the right size, but without this code |
350 | * fragmentation will occur... need more investigation |
351 | */ |
352 | #ifdef INET |
353 | if (inp) { |
354 | #if defined(IPSEC) |
355 | if (ipsec_used && |
356 | !IPSEC_PCB_SKIP_IPSEC(inp->inp_sp, IPSEC_DIR_OUTBOUND)) |
357 | optlen += ipsec4_hdrsiz_tcp(tp); |
358 | #endif |
359 | optlen += ip_optlen(inp); |
360 | } |
361 | #endif |
362 | #ifdef INET6 |
363 | #ifdef INET |
364 | if (in6p && tp->t_family == AF_INET) { |
365 | #if defined(IPSEC) |
366 | if (ipsec_used && |
367 | !IPSEC_PCB_SKIP_IPSEC(in6p->in6p_sp, IPSEC_DIR_OUTBOUND)) |
368 | optlen += ipsec4_hdrsiz_tcp(tp); |
369 | #endif |
370 | /* XXX size -= ip_optlen(in6p); */ |
371 | } else |
372 | #endif |
373 | if (in6p && tp->t_family == AF_INET6) { |
374 | #if defined(IPSEC) |
375 | if (ipsec_used && |
376 | !IPSEC_PCB_SKIP_IPSEC(in6p->in6p_sp, IPSEC_DIR_OUTBOUND)) |
377 | optlen += ipsec6_hdrsiz_tcp(tp); |
378 | #endif |
379 | optlen += ip6_optlen(in6p); |
380 | } |
381 | #endif |
382 | size -= optlen; |
383 | |
384 | /* there may not be any room for data if mtu is too small */ |
385 | if (size < 0) |
386 | return (EMSGSIZE); |
387 | |
388 | /* |
389 | * *rxsegsizep holds *estimated* inbound segment size (estimation |
390 | * assumes that path MTU is the same for both ways). this is only |
391 | * for silly window avoidance, do not use the value for other purposes. |
392 | * |
393 | * ipseclen is subtracted from both sides, this may not be right. |
394 | * I'm not quite sure about this (could someone comment). |
395 | */ |
396 | *txsegsizep = min(tp->t_peermss - optlen, size); |
397 | /* |
398 | * Never send more than half a buffer full. This insures that we can |
399 | * always keep 2 packets on the wire, no matter what SO_SNDBUF is, and |
400 | * therefore acks will never be delayed unless we run out of data to |
401 | * transmit. |
402 | */ |
403 | if (so) |
404 | *txsegsizep = min(so->so_snd.sb_hiwat >> 1, *txsegsizep); |
405 | *rxsegsizep = min(tp->t_ourmss - optlen, size); |
406 | |
407 | if (*txsegsizep != tp->t_segsz) { |
408 | /* |
409 | * If the new segment size is larger, we don't want to |
410 | * mess up the congestion window, but if it is smaller |
411 | * we'll have to reduce the congestion window to ensure |
412 | * that we don't get into trouble with initial windows |
413 | * and the rest. In any case, if the segment size |
414 | * has changed, chances are the path has, too, and |
415 | * our congestion window will be different. |
416 | */ |
417 | if (*txsegsizep < tp->t_segsz) { |
418 | tp->snd_cwnd = max((tp->snd_cwnd / tp->t_segsz) |
419 | * *txsegsizep, *txsegsizep); |
420 | tp->snd_ssthresh = max((tp->snd_ssthresh / tp->t_segsz) |
421 | * *txsegsizep, *txsegsizep); |
422 | } |
423 | tp->t_segsz = *txsegsizep; |
424 | } |
425 | |
426 | return (0); |
427 | } |
428 | |
429 | static |
430 | #ifndef GPROF |
431 | inline |
432 | #endif |
433 | int |
434 | tcp_build_datapkt(struct tcpcb *tp, struct socket *so, int off, |
435 | long len, int hdrlen, struct mbuf **mp) |
436 | { |
437 | struct mbuf *m, *m0; |
438 | uint64_t *tcps; |
439 | |
440 | tcps = TCP_STAT_GETREF(); |
441 | if (tp->t_force && len == 1) |
442 | tcps[TCP_STAT_SNDPROBE]++; |
443 | else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { |
444 | tp->t_sndrexmitpack++; |
445 | tcps[TCP_STAT_SNDREXMITPACK]++; |
446 | tcps[TCP_STAT_SNDREXMITBYTE] += len; |
447 | } else { |
448 | tcps[TCP_STAT_SNDPACK]++; |
449 | tcps[TCP_STAT_SNDBYTE] += len; |
450 | } |
451 | TCP_STAT_PUTREF(); |
452 | #ifdef notyet |
453 | if ((m = m_copypack(so->so_snd.sb_mb, off, |
454 | (int)len, max_linkhdr + hdrlen)) == 0) |
455 | return (ENOBUFS); |
456 | /* |
457 | * m_copypack left space for our hdr; use it. |
458 | */ |
459 | m->m_len += hdrlen; |
460 | m->m_data -= hdrlen; |
461 | #else |
462 | MGETHDR(m, M_DONTWAIT, MT_HEADER); |
463 | if (__predict_false(m == NULL)) |
464 | return (ENOBUFS); |
465 | MCLAIM(m, &tcp_tx_mowner); |
466 | |
467 | /* |
468 | * XXX Because other code assumes headers will fit in |
469 | * XXX one header mbuf. |
470 | * |
471 | * (This code should almost *never* be run.) |
472 | */ |
473 | if (__predict_false((max_linkhdr + hdrlen) > MHLEN)) { |
474 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_bigheader); |
475 | MCLGET(m, M_DONTWAIT); |
476 | if ((m->m_flags & M_EXT) == 0) { |
477 | m_freem(m); |
478 | return (ENOBUFS); |
479 | } |
480 | } |
481 | |
482 | m->m_data += max_linkhdr; |
483 | m->m_len = hdrlen; |
484 | |
485 | /* |
486 | * To avoid traversing the whole sb_mb chain for correct |
487 | * data to send, remember last sent mbuf, its offset and |
488 | * the sent size. When called the next time, see if the |
489 | * data to send is directly following the previous transfer. |
490 | * This is important for large TCP windows. |
491 | */ |
492 | if (off == 0 || tp->t_lastm == NULL || |
493 | (tp->t_lastoff + tp->t_lastlen) != off) { |
494 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_predict_miss); |
495 | /* |
496 | * Either a new packet or a retransmit. |
497 | * Start from the beginning. |
498 | */ |
499 | tp->t_lastm = so->so_snd.sb_mb; |
500 | tp->t_inoff = off; |
501 | } else { |
502 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_predict_hit); |
503 | tp->t_inoff += tp->t_lastlen; |
504 | } |
505 | |
506 | /* Traverse forward to next packet */ |
507 | while (tp->t_inoff > 0) { |
508 | if (tp->t_lastm == NULL) |
509 | panic("tp->t_lastm == NULL" ); |
510 | if (tp->t_inoff < tp->t_lastm->m_len) |
511 | break; |
512 | tp->t_inoff -= tp->t_lastm->m_len; |
513 | tp->t_lastm = tp->t_lastm->m_next; |
514 | } |
515 | |
516 | tp->t_lastoff = off; |
517 | tp->t_lastlen = len; |
518 | m0 = tp->t_lastm; |
519 | off = tp->t_inoff; |
520 | |
521 | if (len <= M_TRAILINGSPACE(m)) { |
522 | m_copydata(m0, off, (int) len, mtod(m, char *) + hdrlen); |
523 | m->m_len += len; |
524 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_copysmall); |
525 | } else { |
526 | m->m_next = m_copym(m0, off, (int) len, M_DONTWAIT); |
527 | if (m->m_next == NULL) { |
528 | m_freem(m); |
529 | return (ENOBUFS); |
530 | } |
531 | #ifdef TCP_OUTPUT_COUNTERS |
532 | if (m->m_next->m_flags & M_EXT) |
533 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_refbig); |
534 | else |
535 | TCP_OUTPUT_COUNTER_INCR(&tcp_output_copybig); |
536 | #endif /* TCP_OUTPUT_COUNTERS */ |
537 | } |
538 | #endif |
539 | |
540 | *mp = m; |
541 | return (0); |
542 | } |
543 | |
544 | /* |
545 | * Tcp output routine: figure out what should be sent and send it. |
546 | */ |
547 | int |
548 | tcp_output(struct tcpcb *tp) |
549 | { |
550 | struct rtentry *rt; |
551 | struct socket *so; |
552 | struct route *ro; |
553 | long len, win; |
554 | int off, flags, error; |
555 | struct mbuf *m; |
556 | struct ip *ip; |
557 | #ifdef INET6 |
558 | struct ip6_hdr *ip6; |
559 | #endif |
560 | struct tcphdr *th; |
561 | u_char opt[MAX_TCPOPTLEN]; |
562 | #define OPT_FITS(more) ((optlen + (more)) < sizeof(opt)) |
563 | unsigned optlen, hdrlen, packetlen; |
564 | unsigned int sack_numblks; |
565 | int idle, sendalot, txsegsize, rxsegsize; |
566 | int txsegsize_nosack; |
567 | int maxburst = TCP_MAXBURST; |
568 | int af; /* address family on the wire */ |
569 | int iphdrlen; |
570 | int has_tso4, has_tso6; |
571 | int has_tso, use_tso; |
572 | bool alwaysfrag; |
573 | int sack_rxmit; |
574 | int sack_bytes_rxmt; |
575 | int ecn_tos; |
576 | struct sackhole *p; |
577 | #ifdef TCP_SIGNATURE |
578 | int sigoff = 0; |
579 | #endif |
580 | uint64_t *tcps; |
581 | |
582 | #ifdef DIAGNOSTIC |
583 | if (tp->t_inpcb && tp->t_in6pcb) |
584 | panic("tcp_output: both t_inpcb and t_in6pcb are set" ); |
585 | #endif |
586 | so = NULL; |
587 | ro = NULL; |
588 | if (tp->t_inpcb) { |
589 | so = tp->t_inpcb->inp_socket; |
590 | ro = &tp->t_inpcb->inp_route; |
591 | } |
592 | #ifdef INET6 |
593 | else if (tp->t_in6pcb) { |
594 | so = tp->t_in6pcb->in6p_socket; |
595 | ro = &tp->t_in6pcb->in6p_route; |
596 | } |
597 | #endif |
598 | |
599 | switch (af = tp->t_family) { |
600 | #ifdef INET |
601 | case AF_INET: |
602 | if (tp->t_inpcb) |
603 | break; |
604 | #ifdef INET6 |
605 | /* mapped addr case */ |
606 | if (tp->t_in6pcb) |
607 | break; |
608 | #endif |
609 | return (EINVAL); |
610 | #endif |
611 | #ifdef INET6 |
612 | case AF_INET6: |
613 | if (tp->t_in6pcb) |
614 | break; |
615 | return (EINVAL); |
616 | #endif |
617 | default: |
618 | return (EAFNOSUPPORT); |
619 | } |
620 | |
621 | if (tcp_segsize(tp, &txsegsize, &rxsegsize, &alwaysfrag)) |
622 | return (EMSGSIZE); |
623 | |
624 | idle = (tp->snd_max == tp->snd_una); |
625 | |
626 | /* |
627 | * Determine if we can use TCP segmentation offload: |
628 | * - If we're using IPv4 |
629 | * - If there is not an IPsec policy that prevents it |
630 | * - If the interface can do it |
631 | */ |
632 | has_tso4 = has_tso6 = false; |
633 | #if defined(INET) |
634 | has_tso4 = tp->t_inpcb != NULL && |
635 | #if defined(IPSEC) |
636 | (!ipsec_used || IPSEC_PCB_SKIP_IPSEC(tp->t_inpcb->inp_sp, |
637 | IPSEC_DIR_OUTBOUND)) && |
638 | #endif |
639 | (rt = rtcache_validate(&tp->t_inpcb->inp_route)) != NULL && |
640 | (rt->rt_ifp->if_capenable & IFCAP_TSOv4) != 0; |
641 | #endif /* defined(INET) */ |
642 | #if defined(INET6) |
643 | has_tso6 = tp->t_in6pcb != NULL && |
644 | #if defined(IPSEC) |
645 | (!ipsec_used || IPSEC_PCB_SKIP_IPSEC(tp->t_in6pcb->in6p_sp, |
646 | IPSEC_DIR_OUTBOUND)) && |
647 | #endif |
648 | (rt = rtcache_validate(&tp->t_in6pcb->in6p_route)) != NULL && |
649 | (rt->rt_ifp->if_capenable & IFCAP_TSOv6) != 0; |
650 | #endif /* defined(INET6) */ |
651 | has_tso = (has_tso4 || has_tso6) && !alwaysfrag; |
652 | |
653 | /* |
654 | * Restart Window computation. From draft-floyd-incr-init-win-03: |
655 | * |
656 | * Optionally, a TCP MAY set the restart window to the |
657 | * minimum of the value used for the initial window and |
658 | * the current value of cwnd (in other words, using a |
659 | * larger value for the restart window should never increase |
660 | * the size of cwnd). |
661 | */ |
662 | if (tcp_cwm) { |
663 | /* |
664 | * Hughes/Touch/Heidemann Congestion Window Monitoring. |
665 | * Count the number of packets currently pending |
666 | * acknowledgement, and limit our congestion window |
667 | * to a pre-determined allowed burst size plus that count. |
668 | * This prevents bursting once all pending packets have |
669 | * been acknowledged (i.e. transmission is idle). |
670 | * |
671 | * XXX Link this to Initial Window? |
672 | */ |
673 | tp->snd_cwnd = min(tp->snd_cwnd, |
674 | (tcp_cwm_burstsize * txsegsize) + |
675 | (tp->snd_nxt - tp->snd_una)); |
676 | } else { |
677 | if (idle && (tcp_now - tp->t_rcvtime) >= tp->t_rxtcur) { |
678 | /* |
679 | * We have been idle for "a while" and no acks are |
680 | * expected to clock out any data we send -- |
681 | * slow start to get ack "clock" running again. |
682 | */ |
683 | int ss = tcp_init_win; |
684 | #ifdef INET |
685 | if (tp->t_inpcb && |
686 | in_localaddr(tp->t_inpcb->inp_faddr)) |
687 | ss = tcp_init_win_local; |
688 | #endif |
689 | #ifdef INET6 |
690 | if (tp->t_in6pcb && |
691 | in6_localaddr(&tp->t_in6pcb->in6p_faddr)) |
692 | ss = tcp_init_win_local; |
693 | #endif |
694 | tp->snd_cwnd = min(tp->snd_cwnd, |
695 | TCP_INITIAL_WINDOW(ss, txsegsize)); |
696 | } |
697 | } |
698 | |
699 | txsegsize_nosack = txsegsize; |
700 | again: |
701 | ecn_tos = 0; |
702 | use_tso = has_tso; |
703 | if ((tp->t_flags & (TF_ECN_SND_CWR|TF_ECN_SND_ECE)) != 0) { |
704 | /* don't duplicate CWR/ECE. */ |
705 | use_tso = 0; |
706 | } |
707 | TCP_REASS_LOCK(tp); |
708 | sack_numblks = tcp_sack_numblks(tp); |
709 | if (sack_numblks) { |
710 | int sackoptlen; |
711 | |
712 | sackoptlen = TCP_SACK_OPTLEN(sack_numblks); |
713 | if (sackoptlen > txsegsize_nosack) { |
714 | sack_numblks = 0; /* give up SACK */ |
715 | txsegsize = txsegsize_nosack; |
716 | } else { |
717 | if ((tp->rcv_sack_flags & TCPSACK_HAVED) != 0) { |
718 | /* don't duplicate D-SACK. */ |
719 | use_tso = 0; |
720 | } |
721 | txsegsize = txsegsize_nosack - sackoptlen; |
722 | } |
723 | } else { |
724 | txsegsize = txsegsize_nosack; |
725 | } |
726 | |
727 | /* |
728 | * Determine length of data that should be transmitted, and |
729 | * flags that should be used. If there is some data or critical |
730 | * controls (SYN, RST) to send, then transmit; otherwise, |
731 | * investigate further. |
732 | * |
733 | * Readjust SACK information to avoid resending duplicate data. |
734 | */ |
735 | if (TCP_SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max)) |
736 | tcp_sack_adjust(tp); |
737 | sendalot = 0; |
738 | off = tp->snd_nxt - tp->snd_una; |
739 | win = min(tp->snd_wnd, tp->snd_cwnd); |
740 | |
741 | flags = tcp_outflags[tp->t_state]; |
742 | |
743 | /* |
744 | * Send any SACK-generated retransmissions. If we're explicitly trying |
745 | * to send out new data (when sendalot is 1), bypass this function. |
746 | * If we retransmit in fast recovery mode, decrement snd_cwnd, since |
747 | * we're replacing a (future) new transmission with a retransmission |
748 | * now, and we previously incremented snd_cwnd in tcp_input(). |
749 | */ |
750 | /* |
751 | * Still in sack recovery , reset rxmit flag to zero. |
752 | */ |
753 | sack_rxmit = 0; |
754 | sack_bytes_rxmt = 0; |
755 | len = 0; |
756 | p = NULL; |
757 | do { |
758 | long cwin; |
759 | if (!TCP_SACK_ENABLED(tp)) |
760 | break; |
761 | if (tp->t_partialacks < 0) |
762 | break; |
763 | p = tcp_sack_output(tp, &sack_bytes_rxmt); |
764 | if (p == NULL) |
765 | break; |
766 | |
767 | cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt; |
768 | if (cwin < 0) |
769 | cwin = 0; |
770 | /* Do not retransmit SACK segments beyond snd_recover */ |
771 | if (SEQ_GT(p->end, tp->snd_recover)) { |
772 | /* |
773 | * (At least) part of sack hole extends beyond |
774 | * snd_recover. Check to see if we can rexmit data |
775 | * for this hole. |
776 | */ |
777 | if (SEQ_GEQ(p->rxmit, tp->snd_recover)) { |
778 | /* |
779 | * Can't rexmit any more data for this hole. |
780 | * That data will be rexmitted in the next |
781 | * sack recovery episode, when snd_recover |
782 | * moves past p->rxmit. |
783 | */ |
784 | p = NULL; |
785 | break; |
786 | } |
787 | /* Can rexmit part of the current hole */ |
788 | len = ((long)ulmin(cwin, tp->snd_recover - p->rxmit)); |
789 | } else |
790 | len = ((long)ulmin(cwin, p->end - p->rxmit)); |
791 | off = p->rxmit - tp->snd_una; |
792 | if (off + len > so->so_snd.sb_cc) { |
793 | /* 1 for TH_FIN */ |
794 | KASSERT(off + len == so->so_snd.sb_cc + 1); |
795 | KASSERT(p->rxmit + len == tp->snd_max); |
796 | len = so->so_snd.sb_cc - off; |
797 | } |
798 | if (len > 0) { |
799 | sack_rxmit = 1; |
800 | sendalot = 1; |
801 | } |
802 | } while (/*CONSTCOND*/0); |
803 | |
804 | /* |
805 | * If in persist timeout with window of 0, send 1 byte. |
806 | * Otherwise, if window is small but nonzero |
807 | * and timer expired, we will send what we can |
808 | * and go to transmit state. |
809 | */ |
810 | if (tp->t_force) { |
811 | if (win == 0) { |
812 | /* |
813 | * If we still have some data to send, then |
814 | * clear the FIN bit. Usually this would |
815 | * happen below when it realizes that we |
816 | * aren't sending all the data. However, |
817 | * if we have exactly 1 byte of unset data, |
818 | * then it won't clear the FIN bit below, |
819 | * and if we are in persist state, we wind |
820 | * up sending the packet without recording |
821 | * that we sent the FIN bit. |
822 | * |
823 | * We can't just blindly clear the FIN bit, |
824 | * because if we don't have any more data |
825 | * to send then the probe will be the FIN |
826 | * itself. |
827 | */ |
828 | if (off < so->so_snd.sb_cc) |
829 | flags &= ~TH_FIN; |
830 | win = 1; |
831 | } else { |
832 | TCP_TIMER_DISARM(tp, TCPT_PERSIST); |
833 | tp->t_rxtshift = 0; |
834 | } |
835 | } |
836 | |
837 | if (sack_rxmit == 0) { |
838 | if (TCP_SACK_ENABLED(tp) && tp->t_partialacks >= 0) { |
839 | long cwin; |
840 | |
841 | /* |
842 | * We are inside of a SACK recovery episode and are |
843 | * sending new data, having retransmitted all the |
844 | * data possible in the scoreboard. |
845 | */ |
846 | if (tp->snd_wnd < so->so_snd.sb_cc) { |
847 | len = tp->snd_wnd - off; |
848 | flags &= ~TH_FIN; |
849 | } else { |
850 | len = so->so_snd.sb_cc - off; |
851 | } |
852 | |
853 | /* |
854 | * From FreeBSD: |
855 | * Don't remove this (len > 0) check ! |
856 | * We explicitly check for len > 0 here (although it |
857 | * isn't really necessary), to work around a gcc |
858 | * optimization issue - to force gcc to compute |
859 | * len above. Without this check, the computation |
860 | * of len is bungled by the optimizer. |
861 | */ |
862 | if (len > 0) { |
863 | cwin = tp->snd_cwnd - |
864 | (tp->snd_nxt - tp->sack_newdata) - |
865 | sack_bytes_rxmt; |
866 | if (cwin < 0) |
867 | cwin = 0; |
868 | if (cwin < len) { |
869 | len = cwin; |
870 | flags &= ~TH_FIN; |
871 | } |
872 | } |
873 | } else if (win < so->so_snd.sb_cc) { |
874 | len = win - off; |
875 | flags &= ~TH_FIN; |
876 | } else { |
877 | len = so->so_snd.sb_cc - off; |
878 | } |
879 | } |
880 | |
881 | if (len < 0) { |
882 | /* |
883 | * If FIN has been sent but not acked, |
884 | * but we haven't been called to retransmit, |
885 | * len will be -1. Otherwise, window shrank |
886 | * after we sent into it. If window shrank to 0, |
887 | * cancel pending retransmit, pull snd_nxt back |
888 | * to (closed) window, and set the persist timer |
889 | * if it isn't already going. If the window didn't |
890 | * close completely, just wait for an ACK. |
891 | * |
892 | * If we have a pending FIN, either it has already been |
893 | * transmitted or it is outside the window, so drop it. |
894 | * If the FIN has been transmitted, but this is not a |
895 | * retransmission, then len must be -1. Therefore we also |
896 | * prevent here the sending of `gratuitous FINs'. This |
897 | * eliminates the need to check for that case below (e.g. |
898 | * to back up snd_nxt before the FIN so that the sequence |
899 | * number is correct). |
900 | */ |
901 | len = 0; |
902 | flags &= ~TH_FIN; |
903 | if (win == 0) { |
904 | TCP_TIMER_DISARM(tp, TCPT_REXMT); |
905 | tp->t_rxtshift = 0; |
906 | tp->snd_nxt = tp->snd_una; |
907 | if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) |
908 | tcp_setpersist(tp); |
909 | } |
910 | } |
911 | |
912 | /* |
913 | * Automatic sizing enables the performance of large buffers |
914 | * and most of the efficiency of small ones by only allocating |
915 | * space when it is needed. |
916 | * |
917 | * The criteria to step up the send buffer one notch are: |
918 | * 1. receive window of remote host is larger than send buffer |
919 | * (with a fudge factor of 5/4th); |
920 | * 2. send buffer is filled to 7/8th with data (so we actually |
921 | * have data to make use of it); |
922 | * 3. send buffer fill has not hit maximal automatic size; |
923 | * 4. our send window (slow start and cogestion controlled) is |
924 | * larger than sent but unacknowledged data in send buffer. |
925 | * |
926 | * The remote host receive window scaling factor may limit the |
927 | * growing of the send buffer before it reaches its allowed |
928 | * maximum. |
929 | * |
930 | * It scales directly with slow start or congestion window |
931 | * and does at most one step per received ACK. This fast |
932 | * scaling has the drawback of growing the send buffer beyond |
933 | * what is strictly necessary to make full use of a given |
934 | * delay*bandwith product. However testing has shown this not |
935 | * to be much of an problem. At worst we are trading wasting |
936 | * of available bandwith (the non-use of it) for wasting some |
937 | * socket buffer memory. |
938 | * |
939 | * TODO: Shrink send buffer during idle periods together |
940 | * with congestion window. Requires another timer. |
941 | */ |
942 | if (tcp_do_autosndbuf && so->so_snd.sb_flags & SB_AUTOSIZE) { |
943 | if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat && |
944 | so->so_snd.sb_cc >= (so->so_snd.sb_hiwat / 8 * 7) && |
945 | so->so_snd.sb_cc < tcp_autosndbuf_max && |
946 | win >= (so->so_snd.sb_cc - (tp->snd_nxt - tp->snd_una))) { |
947 | if (!sbreserve(&so->so_snd, |
948 | min(so->so_snd.sb_hiwat + tcp_autosndbuf_inc, |
949 | tcp_autosndbuf_max), so)) |
950 | so->so_snd.sb_flags &= ~SB_AUTOSIZE; |
951 | } |
952 | } |
953 | |
954 | if (len > txsegsize) { |
955 | if (use_tso) { |
956 | /* |
957 | * Truncate TSO transfers to IP_MAXPACKET, and make |
958 | * sure that we send equal size transfers down the |
959 | * stack (rather than big-small-big-small-...). |
960 | */ |
961 | #ifdef INET6 |
962 | CTASSERT(IPV6_MAXPACKET == IP_MAXPACKET); |
963 | #endif |
964 | len = (min(len, IP_MAXPACKET) / txsegsize) * txsegsize; |
965 | if (len <= txsegsize) { |
966 | use_tso = 0; |
967 | } |
968 | } else |
969 | len = txsegsize; |
970 | flags &= ~TH_FIN; |
971 | sendalot = 1; |
972 | } else |
973 | use_tso = 0; |
974 | if (sack_rxmit) { |
975 | if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) |
976 | flags &= ~TH_FIN; |
977 | } |
978 | |
979 | win = sbspace(&so->so_rcv); |
980 | |
981 | /* |
982 | * Sender silly window avoidance. If connection is idle |
983 | * and can send all data, a maximum segment, |
984 | * at least a maximum default-size segment do it, |
985 | * or are forced, do it; otherwise don't bother. |
986 | * If peer's buffer is tiny, then send |
987 | * when window is at least half open. |
988 | * If retransmitting (possibly after persist timer forced us |
989 | * to send into a small window), then must resend. |
990 | */ |
991 | if (len) { |
992 | if (len >= txsegsize) |
993 | goto send; |
994 | if ((so->so_state & SS_MORETOCOME) == 0 && |
995 | ((idle || tp->t_flags & TF_NODELAY) && |
996 | len + off >= so->so_snd.sb_cc)) |
997 | goto send; |
998 | if (tp->t_force) |
999 | goto send; |
1000 | if (len >= tp->max_sndwnd / 2) |
1001 | goto send; |
1002 | if (SEQ_LT(tp->snd_nxt, tp->snd_max)) |
1003 | goto send; |
1004 | if (sack_rxmit) |
1005 | goto send; |
1006 | } |
1007 | |
1008 | /* |
1009 | * Compare available window to amount of window known to peer |
1010 | * (as advertised window less next expected input). If the |
1011 | * difference is at least twice the size of the largest segment |
1012 | * we expect to receive (i.e. two segments) or at least 50% of |
1013 | * the maximum possible window, then want to send a window update |
1014 | * to peer. |
1015 | */ |
1016 | if (win > 0) { |
1017 | /* |
1018 | * "adv" is the amount we can increase the window, |
1019 | * taking into account that we are limited by |
1020 | * TCP_MAXWIN << tp->rcv_scale. |
1021 | */ |
1022 | long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) - |
1023 | (tp->rcv_adv - tp->rcv_nxt); |
1024 | |
1025 | /* |
1026 | * If the new window size ends up being the same as the old |
1027 | * size when it is scaled, then don't force a window update. |
1028 | */ |
1029 | if ((tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale == |
1030 | (adv + tp->rcv_adv - tp->rcv_nxt) >> tp->rcv_scale) |
1031 | goto dontupdate; |
1032 | if (adv >= (long) (2 * rxsegsize)) |
1033 | goto send; |
1034 | if (2 * adv >= (long) so->so_rcv.sb_hiwat) |
1035 | goto send; |
1036 | } |
1037 | dontupdate: |
1038 | |
1039 | /* |
1040 | * Send if we owe peer an ACK. |
1041 | */ |
1042 | if (tp->t_flags & TF_ACKNOW) |
1043 | goto send; |
1044 | if (flags & (TH_SYN|TH_FIN|TH_RST)) |
1045 | goto send; |
1046 | if (SEQ_GT(tp->snd_up, tp->snd_una)) |
1047 | goto send; |
1048 | /* |
1049 | * In SACK, it is possible for tcp_output to fail to send a segment |
1050 | * after the retransmission timer has been turned off. Make sure |
1051 | * that the retransmission timer is set. |
1052 | */ |
1053 | if (TCP_SACK_ENABLED(tp) && SEQ_GT(tp->snd_max, tp->snd_una) && |
1054 | !TCP_TIMER_ISARMED(tp, TCPT_REXMT) && |
1055 | !TCP_TIMER_ISARMED(tp, TCPT_PERSIST)) { |
1056 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
1057 | goto just_return; |
1058 | } |
1059 | |
1060 | /* |
1061 | * TCP window updates are not reliable, rather a polling protocol |
1062 | * using ``persist'' packets is used to insure receipt of window |
1063 | * updates. The three ``states'' for the output side are: |
1064 | * idle not doing retransmits or persists |
1065 | * persisting to move a small or zero window |
1066 | * (re)transmitting and thereby not persisting |
1067 | * |
1068 | * tp->t_timer[TCPT_PERSIST] |
1069 | * is set when we are in persist state. |
1070 | * tp->t_force |
1071 | * is set when we are called to send a persist packet. |
1072 | * tp->t_timer[TCPT_REXMT] |
1073 | * is set when we are retransmitting |
1074 | * The output side is idle when both timers are zero. |
1075 | * |
1076 | * If send window is too small, there is data to transmit, and no |
1077 | * retransmit or persist is pending, then go to persist state. |
1078 | * If nothing happens soon, send when timer expires: |
1079 | * if window is nonzero, transmit what we can, |
1080 | * otherwise force out a byte. |
1081 | */ |
1082 | if (so->so_snd.sb_cc && TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 && |
1083 | TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) { |
1084 | tp->t_rxtshift = 0; |
1085 | tcp_setpersist(tp); |
1086 | } |
1087 | |
1088 | /* |
1089 | * No reason to send a segment, just return. |
1090 | */ |
1091 | just_return: |
1092 | TCP_REASS_UNLOCK(tp); |
1093 | return (0); |
1094 | |
1095 | send: |
1096 | /* |
1097 | * Before ESTABLISHED, force sending of initial options |
1098 | * unless TCP set not to do any options. |
1099 | * NOTE: we assume that the IP/TCP header plus TCP options |
1100 | * always fit in a single mbuf, leaving room for a maximum |
1101 | * link header, i.e. |
1102 | * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES |
1103 | */ |
1104 | optlen = 0; |
1105 | switch (af) { |
1106 | #ifdef INET |
1107 | case AF_INET: |
1108 | iphdrlen = sizeof(struct ip) + sizeof(struct tcphdr); |
1109 | break; |
1110 | #endif |
1111 | #ifdef INET6 |
1112 | case AF_INET6: |
1113 | iphdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); |
1114 | break; |
1115 | #endif |
1116 | default: /*pacify gcc*/ |
1117 | iphdrlen = 0; |
1118 | break; |
1119 | } |
1120 | hdrlen = iphdrlen; |
1121 | if (flags & TH_SYN) { |
1122 | struct rtentry *synrt; |
1123 | |
1124 | synrt = NULL; |
1125 | #ifdef INET |
1126 | if (tp->t_inpcb) |
1127 | synrt = in_pcbrtentry(tp->t_inpcb); |
1128 | #endif |
1129 | #ifdef INET6 |
1130 | if (tp->t_in6pcb) |
1131 | synrt = in6_pcbrtentry(tp->t_in6pcb); |
1132 | #endif |
1133 | |
1134 | tp->snd_nxt = tp->iss; |
1135 | tp->t_ourmss = tcp_mss_to_advertise(synrt != NULL ? |
1136 | synrt->rt_ifp : NULL, af); |
1137 | if ((tp->t_flags & TF_NOOPT) == 0 && OPT_FITS(4)) { |
1138 | opt[0] = TCPOPT_MAXSEG; |
1139 | opt[1] = 4; |
1140 | opt[2] = (tp->t_ourmss >> 8) & 0xff; |
1141 | opt[3] = tp->t_ourmss & 0xff; |
1142 | optlen = 4; |
1143 | |
1144 | if ((tp->t_flags & TF_REQ_SCALE) && |
1145 | ((flags & TH_ACK) == 0 || |
1146 | (tp->t_flags & TF_RCVD_SCALE)) && |
1147 | OPT_FITS(4)) { |
1148 | *((u_int32_t *) (opt + optlen)) = htonl( |
1149 | TCPOPT_NOP << 24 | |
1150 | TCPOPT_WINDOW << 16 | |
1151 | TCPOLEN_WINDOW << 8 | |
1152 | tp->request_r_scale); |
1153 | optlen += 4; |
1154 | } |
1155 | if (tcp_do_sack && OPT_FITS(4)) { |
1156 | u_int8_t *cp = (u_int8_t *)(opt + optlen); |
1157 | |
1158 | cp[0] = TCPOPT_SACK_PERMITTED; |
1159 | cp[1] = 2; |
1160 | cp[2] = TCPOPT_NOP; |
1161 | cp[3] = TCPOPT_NOP; |
1162 | optlen += 4; |
1163 | } |
1164 | } |
1165 | } |
1166 | |
1167 | /* |
1168 | * Send a timestamp and echo-reply if this is a SYN and our side |
1169 | * wants to use timestamps (TF_REQ_TSTMP is set) or both our side |
1170 | * and our peer have sent timestamps in our SYN's. |
1171 | */ |
1172 | if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && |
1173 | (flags & TH_RST) == 0 && |
1174 | ((flags & (TH_SYN|TH_ACK)) == TH_SYN || |
1175 | (tp->t_flags & TF_RCVD_TSTMP)) && OPT_FITS(TCPOLEN_TSTAMP_APPA)) { |
1176 | u_int32_t *lp = (u_int32_t *)(opt + optlen); |
1177 | |
1178 | /* Form timestamp option as shown in appendix A of RFC 1323. */ |
1179 | *lp++ = htonl(TCPOPT_TSTAMP_HDR); |
1180 | *lp++ = htonl(TCP_TIMESTAMP(tp)); |
1181 | *lp = htonl(tp->ts_recent); |
1182 | optlen += TCPOLEN_TSTAMP_APPA; |
1183 | |
1184 | /* Set receive buffer autosizing timestamp. */ |
1185 | if (tp->rfbuf_ts == 0 && (so->so_rcv.sb_flags & SB_AUTOSIZE)) |
1186 | tp->rfbuf_ts = TCP_TIMESTAMP(tp); |
1187 | } |
1188 | |
1189 | /* |
1190 | * Tack on the SACK block if it is necessary. |
1191 | */ |
1192 | if (sack_numblks) { |
1193 | int sack_len; |
1194 | u_char *bp = (u_char *)(opt + optlen); |
1195 | u_int32_t *lp = (u_int32_t *)(bp + 4); |
1196 | struct ipqent *tiqe; |
1197 | |
1198 | sack_len = sack_numblks * 8 + 2; |
1199 | if (OPT_FITS(sack_len + 2)) { |
1200 | bp[0] = TCPOPT_NOP; |
1201 | bp[1] = TCPOPT_NOP; |
1202 | bp[2] = TCPOPT_SACK; |
1203 | bp[3] = sack_len; |
1204 | if ((tp->rcv_sack_flags & TCPSACK_HAVED) != 0) { |
1205 | sack_numblks--; |
1206 | *lp++ = htonl(tp->rcv_dsack_block.left); |
1207 | *lp++ = htonl(tp->rcv_dsack_block.right); |
1208 | tp->rcv_sack_flags &= ~TCPSACK_HAVED; |
1209 | } |
1210 | for (tiqe = TAILQ_FIRST(&tp->timeq); |
1211 | sack_numblks > 0; |
1212 | tiqe = TAILQ_NEXT(tiqe, ipqe_timeq)) { |
1213 | KASSERT(tiqe != NULL); |
1214 | sack_numblks--; |
1215 | *lp++ = htonl(tiqe->ipqe_seq); |
1216 | *lp++ = htonl(tiqe->ipqe_seq + tiqe->ipqe_len + |
1217 | ((tiqe->ipqe_flags & TH_FIN) != 0 ? 1 : 0)); |
1218 | } |
1219 | optlen += sack_len + 2; |
1220 | } |
1221 | } |
1222 | TCP_REASS_UNLOCK(tp); |
1223 | |
1224 | #ifdef TCP_SIGNATURE |
1225 | if ((tp->t_flags & TF_SIGNATURE) && OPT_FITS(TCPOLEN_SIGNATURE + 2)) { |
1226 | u_char *bp; |
1227 | /* |
1228 | * Initialize TCP-MD5 option (RFC2385) |
1229 | */ |
1230 | bp = (u_char *)opt + optlen; |
1231 | *bp++ = TCPOPT_SIGNATURE; |
1232 | *bp++ = TCPOLEN_SIGNATURE; |
1233 | sigoff = optlen + 2; |
1234 | memset(bp, 0, TCP_SIGLEN); |
1235 | bp += TCP_SIGLEN; |
1236 | optlen += TCPOLEN_SIGNATURE; |
1237 | /* |
1238 | * Terminate options list and maintain 32-bit alignment. |
1239 | */ |
1240 | *bp++ = TCPOPT_NOP; |
1241 | *bp++ = TCPOPT_EOL; |
1242 | optlen += 2; |
1243 | } else if ((tp->t_flags & TF_SIGNATURE) != 0) { |
1244 | error = ECONNABORTED; |
1245 | goto out; |
1246 | } |
1247 | #endif /* TCP_SIGNATURE */ |
1248 | |
1249 | hdrlen += optlen; |
1250 | |
1251 | #ifdef DIAGNOSTIC |
1252 | if (!use_tso && len > txsegsize) |
1253 | panic("tcp data to be sent is larger than segment" ); |
1254 | else if (use_tso && len > IP_MAXPACKET) |
1255 | panic("tcp data to be sent is larger than max TSO size" ); |
1256 | if (max_linkhdr + hdrlen > MCLBYTES) |
1257 | panic("tcphdr too big" ); |
1258 | #endif |
1259 | |
1260 | /* |
1261 | * Grab a header mbuf, attaching a copy of data to |
1262 | * be transmitted, and initialize the header from |
1263 | * the template for sends on this connection. |
1264 | */ |
1265 | if (len) { |
1266 | error = tcp_build_datapkt(tp, so, off, len, hdrlen, &m); |
1267 | if (error) |
1268 | goto out; |
1269 | /* |
1270 | * If we're sending everything we've got, set PUSH. |
1271 | * (This will keep happy those implementations which only |
1272 | * give data to the user when a buffer fills or |
1273 | * a PUSH comes in.) |
1274 | */ |
1275 | if (off + len == so->so_snd.sb_cc) |
1276 | flags |= TH_PUSH; |
1277 | } else { |
1278 | tcps = TCP_STAT_GETREF(); |
1279 | if (tp->t_flags & TF_ACKNOW) |
1280 | tcps[TCP_STAT_SNDACKS]++; |
1281 | else if (flags & (TH_SYN|TH_FIN|TH_RST)) |
1282 | tcps[TCP_STAT_SNDCTRL]++; |
1283 | else if (SEQ_GT(tp->snd_up, tp->snd_una)) |
1284 | tcps[TCP_STAT_SNDURG]++; |
1285 | else |
1286 | tcps[TCP_STAT_SNDWINUP]++; |
1287 | TCP_STAT_PUTREF(); |
1288 | |
1289 | MGETHDR(m, M_DONTWAIT, MT_HEADER); |
1290 | if (m != NULL && max_linkhdr + hdrlen > MHLEN) { |
1291 | MCLGET(m, M_DONTWAIT); |
1292 | if ((m->m_flags & M_EXT) == 0) { |
1293 | m_freem(m); |
1294 | m = NULL; |
1295 | } |
1296 | } |
1297 | if (m == NULL) { |
1298 | error = ENOBUFS; |
1299 | goto out; |
1300 | } |
1301 | MCLAIM(m, &tcp_tx_mowner); |
1302 | m->m_data += max_linkhdr; |
1303 | m->m_len = hdrlen; |
1304 | } |
1305 | m_reset_rcvif(m); |
1306 | switch (af) { |
1307 | #ifdef INET |
1308 | case AF_INET: |
1309 | ip = mtod(m, struct ip *); |
1310 | #ifdef INET6 |
1311 | ip6 = NULL; |
1312 | #endif |
1313 | th = (struct tcphdr *)(ip + 1); |
1314 | break; |
1315 | #endif |
1316 | #ifdef INET6 |
1317 | case AF_INET6: |
1318 | ip = NULL; |
1319 | ip6 = mtod(m, struct ip6_hdr *); |
1320 | th = (struct tcphdr *)(ip6 + 1); |
1321 | break; |
1322 | #endif |
1323 | default: /*pacify gcc*/ |
1324 | ip = NULL; |
1325 | #ifdef INET6 |
1326 | ip6 = NULL; |
1327 | #endif |
1328 | th = NULL; |
1329 | break; |
1330 | } |
1331 | if (tp->t_template == 0) |
1332 | panic("tcp_output" ); |
1333 | if (tp->t_template->m_len < iphdrlen) |
1334 | panic("tcp_output" ); |
1335 | bcopy(mtod(tp->t_template, void *), mtod(m, void *), iphdrlen); |
1336 | |
1337 | /* |
1338 | * If we are starting a connection, send ECN setup |
1339 | * SYN packet. If we are on a retransmit, we may |
1340 | * resend those bits a number of times as per |
1341 | * RFC 3168. |
1342 | */ |
1343 | if (tp->t_state == TCPS_SYN_SENT && tcp_do_ecn) { |
1344 | if (tp->t_flags & TF_SYN_REXMT) { |
1345 | if (tp->t_ecn_retries--) |
1346 | flags |= TH_ECE|TH_CWR; |
1347 | } else { |
1348 | flags |= TH_ECE|TH_CWR; |
1349 | tp->t_ecn_retries = tcp_ecn_maxretries; |
1350 | } |
1351 | } |
1352 | |
1353 | if (TCP_ECN_ALLOWED(tp)) { |
1354 | /* |
1355 | * If the peer has ECN, mark data packets |
1356 | * ECN capable. Ignore pure ack packets, retransmissions |
1357 | * and window probes. |
1358 | */ |
1359 | if (len > 0 && SEQ_GEQ(tp->snd_nxt, tp->snd_max) && |
1360 | !(tp->t_force && len == 1)) { |
1361 | ecn_tos = IPTOS_ECN_ECT0; |
1362 | TCP_STATINC(TCP_STAT_ECN_ECT); |
1363 | } |
1364 | |
1365 | /* |
1366 | * Reply with proper ECN notifications. |
1367 | */ |
1368 | if (tp->t_flags & TF_ECN_SND_CWR) { |
1369 | flags |= TH_CWR; |
1370 | tp->t_flags &= ~TF_ECN_SND_CWR; |
1371 | } |
1372 | if (tp->t_flags & TF_ECN_SND_ECE) { |
1373 | flags |= TH_ECE; |
1374 | } |
1375 | } |
1376 | |
1377 | |
1378 | /* |
1379 | * If we are doing retransmissions, then snd_nxt will |
1380 | * not reflect the first unsent octet. For ACK only |
1381 | * packets, we do not want the sequence number of the |
1382 | * retransmitted packet, we want the sequence number |
1383 | * of the next unsent octet. So, if there is no data |
1384 | * (and no SYN or FIN), use snd_max instead of snd_nxt |
1385 | * when filling in ti_seq. But if we are in persist |
1386 | * state, snd_max might reflect one byte beyond the |
1387 | * right edge of the window, so use snd_nxt in that |
1388 | * case, since we know we aren't doing a retransmission. |
1389 | * (retransmit and persist are mutually exclusive...) |
1390 | */ |
1391 | if (TCP_SACK_ENABLED(tp) && sack_rxmit) { |
1392 | th->th_seq = htonl(p->rxmit); |
1393 | p->rxmit += len; |
1394 | } else { |
1395 | if (len || (flags & (TH_SYN|TH_FIN)) || |
1396 | TCP_TIMER_ISARMED(tp, TCPT_PERSIST)) |
1397 | th->th_seq = htonl(tp->snd_nxt); |
1398 | else |
1399 | th->th_seq = htonl(tp->snd_max); |
1400 | } |
1401 | th->th_ack = htonl(tp->rcv_nxt); |
1402 | if (optlen) { |
1403 | bcopy((void *)opt, (void *)(th + 1), optlen); |
1404 | th->th_off = (sizeof (struct tcphdr) + optlen) >> 2; |
1405 | } |
1406 | th->th_flags = flags; |
1407 | /* |
1408 | * Calculate receive window. Don't shrink window, |
1409 | * but avoid silly window syndrome. |
1410 | */ |
1411 | if (win < (long)(so->so_rcv.sb_hiwat / 4) && win < (long)rxsegsize) |
1412 | win = 0; |
1413 | if (win > (long)TCP_MAXWIN << tp->rcv_scale) |
1414 | win = (long)TCP_MAXWIN << tp->rcv_scale; |
1415 | if (win < (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt)) |
1416 | win = (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt); |
1417 | th->th_win = htons((u_int16_t) (win>>tp->rcv_scale)); |
1418 | if (th->th_win == 0) { |
1419 | tp->t_sndzerowin++; |
1420 | } |
1421 | if (SEQ_GT(tp->snd_up, tp->snd_nxt)) { |
1422 | u_int32_t urp = tp->snd_up - tp->snd_nxt; |
1423 | if (urp > IP_MAXPACKET) |
1424 | urp = IP_MAXPACKET; |
1425 | th->th_urp = htons((u_int16_t)urp); |
1426 | th->th_flags |= TH_URG; |
1427 | } else |
1428 | /* |
1429 | * If no urgent pointer to send, then we pull |
1430 | * the urgent pointer to the left edge of the send window |
1431 | * so that it doesn't drift into the send window on sequence |
1432 | * number wraparound. |
1433 | */ |
1434 | tp->snd_up = tp->snd_una; /* drag it along */ |
1435 | |
1436 | #ifdef TCP_SIGNATURE |
1437 | if (sigoff && (tp->t_flags & TF_SIGNATURE)) { |
1438 | struct secasvar *sav; |
1439 | u_int8_t *sigp; |
1440 | |
1441 | sav = tcp_signature_getsav(m, th); |
1442 | |
1443 | if (sav == NULL) { |
1444 | if (m) |
1445 | m_freem(m); |
1446 | return (EPERM); |
1447 | } |
1448 | |
1449 | m->m_pkthdr.len = hdrlen + len; |
1450 | sigp = (char *)th + sizeof(*th) + sigoff; |
1451 | tcp_signature(m, th, (char *)th - mtod(m, char *), sav, sigp); |
1452 | |
1453 | key_sa_recordxfer(sav, m); |
1454 | KEY_FREESAV(&sav); |
1455 | } |
1456 | #endif |
1457 | |
1458 | /* |
1459 | * Set ourselves up to be checksummed just before the packet |
1460 | * hits the wire. |
1461 | */ |
1462 | switch (af) { |
1463 | #ifdef INET |
1464 | case AF_INET: |
1465 | m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); |
1466 | if (use_tso) { |
1467 | m->m_pkthdr.segsz = txsegsize; |
1468 | m->m_pkthdr.csum_flags = M_CSUM_TSOv4; |
1469 | } else { |
1470 | m->m_pkthdr.csum_flags = M_CSUM_TCPv4; |
1471 | if (len + optlen) { |
1472 | /* Fixup the pseudo-header checksum. */ |
1473 | /* XXXJRT Not IP Jumbogram safe. */ |
1474 | th->th_sum = in_cksum_addword(th->th_sum, |
1475 | htons((u_int16_t) (len + optlen))); |
1476 | } |
1477 | } |
1478 | break; |
1479 | #endif |
1480 | #ifdef INET6 |
1481 | case AF_INET6: |
1482 | m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); |
1483 | if (use_tso) { |
1484 | m->m_pkthdr.segsz = txsegsize; |
1485 | m->m_pkthdr.csum_flags = M_CSUM_TSOv6; |
1486 | } else { |
1487 | m->m_pkthdr.csum_flags = M_CSUM_TCPv6; |
1488 | if (len + optlen) { |
1489 | /* Fixup the pseudo-header checksum. */ |
1490 | /* XXXJRT: Not IPv6 Jumbogram safe. */ |
1491 | th->th_sum = in_cksum_addword(th->th_sum, |
1492 | htons((u_int16_t) (len + optlen))); |
1493 | } |
1494 | } |
1495 | break; |
1496 | #endif |
1497 | } |
1498 | |
1499 | /* |
1500 | * In transmit state, time the transmission and arrange for |
1501 | * the retransmit. In persist state, just set snd_max. |
1502 | */ |
1503 | if (tp->t_force == 0 || TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) { |
1504 | tcp_seq startseq = tp->snd_nxt; |
1505 | |
1506 | /* |
1507 | * Advance snd_nxt over sequence space of this segment. |
1508 | * There are no states in which we send both a SYN and a FIN, |
1509 | * so we collapse the tests for these flags. |
1510 | */ |
1511 | if (flags & (TH_SYN|TH_FIN)) |
1512 | tp->snd_nxt++; |
1513 | if (sack_rxmit) |
1514 | goto timer; |
1515 | tp->snd_nxt += len; |
1516 | if (SEQ_GT(tp->snd_nxt, tp->snd_max)) { |
1517 | tp->snd_max = tp->snd_nxt; |
1518 | /* |
1519 | * Time this transmission if not a retransmission and |
1520 | * not currently timing anything. |
1521 | */ |
1522 | if (tp->t_rtttime == 0) { |
1523 | tp->t_rtttime = tcp_now; |
1524 | tp->t_rtseq = startseq; |
1525 | TCP_STATINC(TCP_STAT_SEGSTIMED); |
1526 | } |
1527 | } |
1528 | |
1529 | /* |
1530 | * Set retransmit timer if not currently set, |
1531 | * and not doing an ack or a keep-alive probe. |
1532 | * Initial value for retransmit timer is smoothed |
1533 | * round-trip time + 2 * round-trip time variance. |
1534 | * Initialize shift counter which is used for backoff |
1535 | * of retransmit time. |
1536 | */ |
1537 | timer: |
1538 | if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0) { |
1539 | if ((sack_rxmit && tp->snd_nxt != tp->snd_max) |
1540 | || tp->snd_nxt != tp->snd_una) { |
1541 | if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST)) { |
1542 | TCP_TIMER_DISARM(tp, TCPT_PERSIST); |
1543 | tp->t_rxtshift = 0; |
1544 | } |
1545 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur); |
1546 | } else if (len == 0 && so->so_snd.sb_cc > 0 |
1547 | && TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) { |
1548 | /* |
1549 | * If we are sending a window probe and there's |
1550 | * unacked data in the socket, make sure at |
1551 | * least the persist timer is running. |
1552 | */ |
1553 | tp->t_rxtshift = 0; |
1554 | tcp_setpersist(tp); |
1555 | } |
1556 | } |
1557 | } else |
1558 | if (SEQ_GT(tp->snd_nxt + len, tp->snd_max)) |
1559 | tp->snd_max = tp->snd_nxt + len; |
1560 | |
1561 | #ifdef TCP_DEBUG |
1562 | /* |
1563 | * Trace. |
1564 | */ |
1565 | if (so->so_options & SO_DEBUG) |
1566 | tcp_trace(TA_OUTPUT, tp->t_state, tp, m, 0); |
1567 | #endif |
1568 | |
1569 | /* |
1570 | * Fill in IP length and desired time to live and |
1571 | * send to IP level. There should be a better way |
1572 | * to handle ttl and tos; we could keep them in |
1573 | * the template, but need a way to checksum without them. |
1574 | */ |
1575 | m->m_pkthdr.len = hdrlen + len; |
1576 | |
1577 | switch (af) { |
1578 | #ifdef INET |
1579 | case AF_INET: |
1580 | ip->ip_len = htons(m->m_pkthdr.len); |
1581 | packetlen = m->m_pkthdr.len; |
1582 | if (tp->t_inpcb) { |
1583 | ip->ip_ttl = tp->t_inpcb->inp_ip.ip_ttl; |
1584 | ip->ip_tos = tp->t_inpcb->inp_ip.ip_tos | ecn_tos; |
1585 | } |
1586 | #ifdef INET6 |
1587 | else if (tp->t_in6pcb) { |
1588 | ip->ip_ttl = in6_selecthlim(tp->t_in6pcb, NULL); /*XXX*/ |
1589 | ip->ip_tos = ecn_tos; /*XXX*/ |
1590 | } |
1591 | #endif |
1592 | break; |
1593 | #endif |
1594 | #ifdef INET6 |
1595 | case AF_INET6: |
1596 | packetlen = m->m_pkthdr.len; |
1597 | ip6->ip6_nxt = IPPROTO_TCP; |
1598 | if (tp->t_in6pcb) { |
1599 | /* |
1600 | * we separately set hoplimit for every segment, since |
1601 | * the user might want to change the value via |
1602 | * setsockopt. Also, desired default hop limit might |
1603 | * be changed via Neighbor Discovery. |
1604 | */ |
1605 | ip6->ip6_hlim = in6_selecthlim_rt(tp->t_in6pcb); |
1606 | } |
1607 | ip6->ip6_flow |= htonl(ecn_tos << 20); |
1608 | /* ip6->ip6_flow = ??? (from template) */ |
1609 | /* ip6_plen will be filled in ip6_output(). */ |
1610 | break; |
1611 | #endif |
1612 | default: /*pacify gcc*/ |
1613 | packetlen = 0; |
1614 | break; |
1615 | } |
1616 | |
1617 | switch (af) { |
1618 | #ifdef INET |
1619 | case AF_INET: |
1620 | { |
1621 | struct mbuf *opts; |
1622 | |
1623 | if (tp->t_inpcb) |
1624 | opts = tp->t_inpcb->inp_options; |
1625 | else |
1626 | opts = NULL; |
1627 | error = ip_output(m, opts, ro, |
1628 | (tp->t_mtudisc ? IP_MTUDISC : 0) | |
1629 | (so->so_options & SO_DONTROUTE), NULL, so); |
1630 | break; |
1631 | } |
1632 | #endif |
1633 | #ifdef INET6 |
1634 | case AF_INET6: |
1635 | { |
1636 | struct ip6_pktopts *opts; |
1637 | |
1638 | if (tp->t_in6pcb) |
1639 | opts = tp->t_in6pcb->in6p_outputopts; |
1640 | else |
1641 | opts = NULL; |
1642 | error = ip6_output(m, opts, ro, so->so_options & SO_DONTROUTE, |
1643 | NULL, so, NULL); |
1644 | break; |
1645 | } |
1646 | #endif |
1647 | default: |
1648 | error = EAFNOSUPPORT; |
1649 | break; |
1650 | } |
1651 | if (error) { |
1652 | out: |
1653 | if (error == ENOBUFS) { |
1654 | TCP_STATINC(TCP_STAT_SELFQUENCH); |
1655 | #ifdef INET |
1656 | if (tp->t_inpcb) |
1657 | tcp_quench(tp->t_inpcb, 0); |
1658 | #endif |
1659 | #ifdef INET6 |
1660 | if (tp->t_in6pcb) |
1661 | tcp6_quench(tp->t_in6pcb, 0); |
1662 | #endif |
1663 | error = 0; |
1664 | } else if ((error == EHOSTUNREACH || error == ENETDOWN) && |
1665 | TCPS_HAVERCVDSYN(tp->t_state)) { |
1666 | tp->t_softerror = error; |
1667 | error = 0; |
1668 | } |
1669 | |
1670 | /* Back out the seqence number advance. */ |
1671 | if (sack_rxmit) |
1672 | p->rxmit -= len; |
1673 | |
1674 | /* Restart the delayed ACK timer, if necessary. */ |
1675 | if (tp->t_flags & TF_DELACK) |
1676 | TCP_RESTART_DELACK(tp); |
1677 | |
1678 | return (error); |
1679 | } |
1680 | |
1681 | if (packetlen > tp->t_pmtud_mtu_sent) |
1682 | tp->t_pmtud_mtu_sent = packetlen; |
1683 | |
1684 | tcps = TCP_STAT_GETREF(); |
1685 | tcps[TCP_STAT_SNDTOTAL]++; |
1686 | if (tp->t_flags & TF_DELACK) |
1687 | tcps[TCP_STAT_DELACK]++; |
1688 | TCP_STAT_PUTREF(); |
1689 | |
1690 | /* |
1691 | * Data sent (as far as we can tell). |
1692 | * If this advertises a larger window than any other segment, |
1693 | * then remember the size of the advertised window. |
1694 | * Any pending ACK has now been sent. |
1695 | */ |
1696 | if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv)) |
1697 | tp->rcv_adv = tp->rcv_nxt + win; |
1698 | tp->last_ack_sent = tp->rcv_nxt; |
1699 | tp->t_flags &= ~TF_ACKNOW; |
1700 | TCP_CLEAR_DELACK(tp); |
1701 | #ifdef DIAGNOSTIC |
1702 | if (maxburst < 0) |
1703 | printf("tcp_output: maxburst exceeded by %d\n" , -maxburst); |
1704 | #endif |
1705 | if (sendalot && (tp->t_congctl == &tcp_reno_ctl || --maxburst)) |
1706 | goto again; |
1707 | return (0); |
1708 | } |
1709 | |
1710 | void |
1711 | tcp_setpersist(struct tcpcb *tp) |
1712 | { |
1713 | int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2); |
1714 | int nticks; |
1715 | |
1716 | if (TCP_TIMER_ISARMED(tp, TCPT_REXMT)) |
1717 | panic("tcp_output REXMT" ); |
1718 | /* |
1719 | * Start/restart persistance timer. |
1720 | */ |
1721 | if (t < tp->t_rttmin) |
1722 | t = tp->t_rttmin; |
1723 | TCPT_RANGESET(nticks, t * tcp_backoff[tp->t_rxtshift], |
1724 | TCPTV_PERSMIN, TCPTV_PERSMAX); |
1725 | TCP_TIMER_ARM(tp, TCPT_PERSIST, nticks); |
1726 | if (tp->t_rxtshift < TCP_MAXRXTSHIFT) |
1727 | tp->t_rxtshift++; |
1728 | } |
1729 | |