| 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 | |