bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1988, 1990, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. All advertising materials mentioning features or use of this software |
| 14 | * must display the following acknowledgement: |
| 15 | * This product includes software developed by the University of |
| 16 | * California, Berkeley and its contributors. |
| 17 | * 4. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | * |
| 33 | * @(#)tcp_output.c 8.3 (Berkeley) 12/30/93 |
| 34 | * tcp_output.c,v 1.3 1994/09/15 10:36:55 davidg Exp |
| 35 | */ |
| 36 | |
| 37 | /* |
| 38 | * Changes and additions relating to SLiRP |
| 39 | * Copyright (c) 1995 Danny Gasparovski. |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 40 | * |
| 41 | * Please read the file COPYRIGHT for the |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 42 | * terms and conditions of the copyright. |
| 43 | */ |
| 44 | |
| 45 | #include <slirp.h> |
| 46 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 47 | /* |
| 48 | * Since this is only used in "stats socket", we give meaning |
| 49 | * names instead of the REAL names |
| 50 | */ |
| 51 | char *tcpstates[] = { |
| 52 | /* "CLOSED", "LISTEN", "SYN_SENT", "SYN_RCVD", */ |
| 53 | "REDIRECT", "LISTEN", "SYN_SENT", "SYN_RCVD", |
| 54 | "ESTABLISHED", "CLOSE_WAIT", "FIN_WAIT_1", "CLOSING", |
| 55 | "LAST_ACK", "FIN_WAIT_2", "TIME_WAIT", |
| 56 | }; |
| 57 | |
| 58 | u_char tcp_outflags[TCP_NSTATES] = { |
| 59 | TH_RST|TH_ACK, 0, TH_SYN, TH_SYN|TH_ACK, |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 60 | TH_ACK, TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK, |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 61 | TH_FIN|TH_ACK, TH_ACK, TH_ACK, |
| 62 | }; |
| 63 | |
| 64 | |
| 65 | #define MAX_TCPOPTLEN 32 /* max # bytes that go in options */ |
| 66 | |
| 67 | /* |
| 68 | * Tcp output routine: figure out what should be sent and send it. |
| 69 | */ |
| 70 | int |
| 71 | tcp_output(tp) |
| 72 | register struct tcpcb *tp; |
| 73 | { |
| 74 | register struct socket *so = tp->t_socket; |
| 75 | register long len, win; |
| 76 | int off, flags, error; |
| 77 | register struct mbuf *m; |
| 78 | register struct tcpiphdr *ti; |
| 79 | u_char opt[MAX_TCPOPTLEN]; |
| 80 | unsigned optlen, hdrlen; |
| 81 | int idle, sendalot; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 82 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 83 | DEBUG_CALL("tcp_output"); |
| 84 | DEBUG_ARG("tp = %lx", (long )tp); |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 85 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 86 | /* |
| 87 | * Determine length of data that should be transmitted, |
| 88 | * and flags that will be used. |
| 89 | * If there is some data or critical controls (SYN, RST) |
| 90 | * to send, then transmit; otherwise, investigate further. |
| 91 | */ |
| 92 | idle = (tp->snd_max == tp->snd_una); |
| 93 | if (idle && tp->t_idle >= tp->t_rxtcur) |
| 94 | /* |
| 95 | * We have been idle for "a while" and no acks are |
| 96 | * expected to clock out any data we send -- |
| 97 | * slow start to get ack "clock" running again. |
| 98 | */ |
| 99 | tp->snd_cwnd = tp->t_maxseg; |
| 100 | again: |
| 101 | sendalot = 0; |
| 102 | off = tp->snd_nxt - tp->snd_una; |
| 103 | win = min(tp->snd_wnd, tp->snd_cwnd); |
| 104 | |
| 105 | flags = tcp_outflags[tp->t_state]; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 106 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 107 | DEBUG_MISC((dfd, " --- tcp_output flags = 0x%x\n",flags)); |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 108 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 109 | /* |
| 110 | * If in persist timeout with window of 0, send 1 byte. |
| 111 | * Otherwise, if window is small but nonzero |
| 112 | * and timer expired, we will send what we can |
| 113 | * and go to transmit state. |
| 114 | */ |
| 115 | if (tp->t_force) { |
| 116 | if (win == 0) { |
| 117 | /* |
| 118 | * If we still have some data to send, then |
| 119 | * clear the FIN bit. Usually this would |
| 120 | * happen below when it realizes that we |
| 121 | * aren't sending all the data. However, |
| 122 | * if we have exactly 1 byte of unset data, |
| 123 | * then it won't clear the FIN bit below, |
| 124 | * and if we are in persist state, we wind |
| 125 | * up sending the packet without recording |
| 126 | * that we sent the FIN bit. |
| 127 | * |
| 128 | * We can't just blindly clear the FIN bit, |
| 129 | * because if we don't have any more data |
| 130 | * to send then the probe will be the FIN |
| 131 | * itself. |
| 132 | */ |
| 133 | if (off < so->so_snd.sb_cc) |
| 134 | flags &= ~TH_FIN; |
| 135 | win = 1; |
| 136 | } else { |
| 137 | tp->t_timer[TCPT_PERSIST] = 0; |
| 138 | tp->t_rxtshift = 0; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | len = min(so->so_snd.sb_cc, win) - off; |
| 143 | |
| 144 | if (len < 0) { |
| 145 | /* |
| 146 | * If FIN has been sent but not acked, |
| 147 | * but we haven't been called to retransmit, |
| 148 | * len will be -1. Otherwise, window shrank |
| 149 | * after we sent into it. If window shrank to 0, |
| 150 | * cancel pending retransmit and pull snd_nxt |
| 151 | * back to (closed) window. We will enter persist |
| 152 | * state below. If the window didn't close completely, |
| 153 | * just wait for an ACK. |
| 154 | */ |
| 155 | len = 0; |
| 156 | if (win == 0) { |
| 157 | tp->t_timer[TCPT_REXMT] = 0; |
| 158 | tp->snd_nxt = tp->snd_una; |
| 159 | } |
| 160 | } |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 161 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 162 | if (len > tp->t_maxseg) { |
| 163 | len = tp->t_maxseg; |
| 164 | sendalot = 1; |
| 165 | } |
| 166 | if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) |
| 167 | flags &= ~TH_FIN; |
| 168 | |
| 169 | win = sbspace(&so->so_rcv); |
| 170 | |
| 171 | /* |
| 172 | * Sender silly window avoidance. If connection is idle |
| 173 | * and can send all data, a maximum segment, |
| 174 | * at least a maximum default-size segment do it, |
| 175 | * or are forced, do it; otherwise don't bother. |
| 176 | * If peer's buffer is tiny, then send |
| 177 | * when window is at least half open. |
| 178 | * If retransmitting (possibly after persist timer forced us |
| 179 | * to send into a small window), then must resend. |
| 180 | */ |
| 181 | if (len) { |
| 182 | if (len == tp->t_maxseg) |
| 183 | goto send; |
| 184 | if ((1 || idle || tp->t_flags & TF_NODELAY) && |
| 185 | len + off >= so->so_snd.sb_cc) |
| 186 | goto send; |
| 187 | if (tp->t_force) |
| 188 | goto send; |
| 189 | if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) |
| 190 | goto send; |
| 191 | if (SEQ_LT(tp->snd_nxt, tp->snd_max)) |
| 192 | goto send; |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | * Compare available window to amount of window |
| 197 | * known to peer (as advertised window less |
| 198 | * next expected input). If the difference is at least two |
| 199 | * max size segments, or at least 50% of the maximum possible |
| 200 | * window, then want to send a window update to peer. |
| 201 | */ |
| 202 | if (win > 0) { |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 203 | /* |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 204 | * "adv" is the amount we can increase the window, |
| 205 | * taking into account that we are limited by |
| 206 | * TCP_MAXWIN << tp->rcv_scale. |
| 207 | */ |
| 208 | long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) - |
| 209 | (tp->rcv_adv - tp->rcv_nxt); |
| 210 | |
| 211 | if (adv >= (long) (2 * tp->t_maxseg)) |
| 212 | goto send; |
| 213 | if (2 * adv >= (long) so->so_rcv.sb_datalen) |
| 214 | goto send; |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Send if we owe peer an ACK. |
| 219 | */ |
| 220 | if (tp->t_flags & TF_ACKNOW) |
| 221 | goto send; |
| 222 | if (flags & (TH_SYN|TH_RST)) |
| 223 | goto send; |
| 224 | if (SEQ_GT(tp->snd_up, tp->snd_una)) |
| 225 | goto send; |
| 226 | /* |
| 227 | * If our state indicates that FIN should be sent |
| 228 | * and we have not yet done so, or we're retransmitting the FIN, |
| 229 | * then we need to send. |
| 230 | */ |
| 231 | if (flags & TH_FIN && |
| 232 | ((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una)) |
| 233 | goto send; |
| 234 | |
| 235 | /* |
| 236 | * TCP window updates are not reliable, rather a polling protocol |
| 237 | * using ``persist'' packets is used to insure receipt of window |
| 238 | * updates. The three ``states'' for the output side are: |
| 239 | * idle not doing retransmits or persists |
| 240 | * persisting to move a small or zero window |
| 241 | * (re)transmitting and thereby not persisting |
| 242 | * |
| 243 | * tp->t_timer[TCPT_PERSIST] |
| 244 | * is set when we are in persist state. |
| 245 | * tp->t_force |
| 246 | * is set when we are called to send a persist packet. |
| 247 | * tp->t_timer[TCPT_REXMT] |
| 248 | * is set when we are retransmitting |
| 249 | * The output side is idle when both timers are zero. |
| 250 | * |
| 251 | * If send window is too small, there is data to transmit, and no |
| 252 | * retransmit or persist is pending, then go to persist state. |
| 253 | * If nothing happens soon, send when timer expires: |
| 254 | * if window is nonzero, transmit what we can, |
| 255 | * otherwise force out a byte. |
| 256 | */ |
| 257 | if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 && |
| 258 | tp->t_timer[TCPT_PERSIST] == 0) { |
| 259 | tp->t_rxtshift = 0; |
| 260 | tcp_setpersist(tp); |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * No reason to send a segment, just return. |
| 265 | */ |
| 266 | tcpstat.tcps_didnuttin++; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 267 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 268 | return (0); |
| 269 | |
| 270 | send: |
| 271 | /* |
| 272 | * Before ESTABLISHED, force sending of initial options |
| 273 | * unless TCP set not to do any options. |
| 274 | * NOTE: we assume that the IP/TCP header plus TCP options |
| 275 | * always fit in a single mbuf, leaving room for a maximum |
| 276 | * link header, i.e. |
| 277 | * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN |
| 278 | */ |
| 279 | optlen = 0; |
| 280 | hdrlen = sizeof (struct tcpiphdr); |
| 281 | if (flags & TH_SYN) { |
| 282 | tp->snd_nxt = tp->iss; |
| 283 | if ((tp->t_flags & TF_NOOPT) == 0) { |
| 284 | u_int16_t mss; |
| 285 | |
| 286 | opt[0] = TCPOPT_MAXSEG; |
| 287 | opt[1] = 4; |
| 288 | mss = htons((u_int16_t) tcp_mss(tp, 0)); |
| 289 | memcpy((caddr_t)(opt + 2), (caddr_t)&mss, sizeof(mss)); |
| 290 | optlen = 4; |
| 291 | |
| 292 | /* if ((tp->t_flags & TF_REQ_SCALE) && |
| 293 | * ((flags & TH_ACK) == 0 || |
| 294 | * (tp->t_flags & TF_RCVD_SCALE))) { |
| 295 | * *((u_int32_t *) (opt + optlen)) = htonl( |
| 296 | * TCPOPT_NOP << 24 | |
| 297 | * TCPOPT_WINDOW << 16 | |
| 298 | * TCPOLEN_WINDOW << 8 | |
| 299 | * tp->request_r_scale); |
| 300 | * optlen += 4; |
| 301 | * } |
| 302 | */ |
| 303 | } |
| 304 | } |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 305 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 306 | /* |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 307 | * Send a timestamp and echo-reply if this is a SYN and our side |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 308 | * wants to use timestamps (TF_REQ_TSTMP is set) or both our side |
| 309 | * and our peer have sent timestamps in our SYN's. |
| 310 | */ |
| 311 | /* if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && |
| 312 | * (flags & TH_RST) == 0 && |
| 313 | * ((flags & (TH_SYN|TH_ACK)) == TH_SYN || |
| 314 | * (tp->t_flags & TF_RCVD_TSTMP))) { |
| 315 | * u_int32_t *lp = (u_int32_t *)(opt + optlen); |
| 316 | * |
| 317 | * / * Form timestamp option as shown in appendix A of RFC 1323. * / |
| 318 | * *lp++ = htonl(TCPOPT_TSTAMP_HDR); |
| 319 | * *lp++ = htonl(tcp_now); |
| 320 | * *lp = htonl(tp->ts_recent); |
| 321 | * optlen += TCPOLEN_TSTAMP_APPA; |
| 322 | * } |
| 323 | */ |
| 324 | hdrlen += optlen; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 325 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 326 | /* |
| 327 | * Adjust data length if insertion of options will |
| 328 | * bump the packet length beyond the t_maxseg length. |
| 329 | */ |
| 330 | if (len > tp->t_maxseg - optlen) { |
| 331 | len = tp->t_maxseg - optlen; |
| 332 | sendalot = 1; |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * Grab a header mbuf, attaching a copy of data to |
| 337 | * be transmitted, and initialize the header from |
| 338 | * the template for sends on this connection. |
| 339 | */ |
| 340 | if (len) { |
| 341 | if (tp->t_force && len == 1) |
| 342 | tcpstat.tcps_sndprobe++; |
| 343 | else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { |
| 344 | tcpstat.tcps_sndrexmitpack++; |
| 345 | tcpstat.tcps_sndrexmitbyte += len; |
| 346 | } else { |
| 347 | tcpstat.tcps_sndpack++; |
| 348 | tcpstat.tcps_sndbyte += len; |
| 349 | } |
| 350 | |
| 351 | m = m_get(); |
| 352 | if (m == NULL) { |
| 353 | /* error = ENOBUFS; */ |
| 354 | error = 1; |
| 355 | goto out; |
| 356 | } |
| 357 | m->m_data += if_maxlinkhdr; |
| 358 | m->m_len = hdrlen; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 359 | |
| 360 | /* |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 361 | * This will always succeed, since we make sure our mbufs |
| 362 | * are big enough to hold one MSS packet + header + ... etc. |
| 363 | */ |
| 364 | /* if (len <= MHLEN - hdrlen - max_linkhdr) { */ |
| 365 | |
| 366 | sbcopy(&so->so_snd, off, (int) len, mtod(m, caddr_t) + hdrlen); |
| 367 | m->m_len += len; |
| 368 | |
| 369 | /* } else { |
| 370 | * m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len); |
| 371 | * if (m->m_next == 0) |
| 372 | * len = 0; |
| 373 | * } |
| 374 | */ |
| 375 | /* |
| 376 | * If we're sending everything we've got, set PUSH. |
| 377 | * (This will keep happy those implementations which only |
| 378 | * give data to the user when a buffer fills or |
| 379 | * a PUSH comes in.) |
| 380 | */ |
| 381 | if (off + len == so->so_snd.sb_cc) |
| 382 | flags |= TH_PUSH; |
| 383 | } else { |
| 384 | if (tp->t_flags & TF_ACKNOW) |
| 385 | tcpstat.tcps_sndacks++; |
| 386 | else if (flags & (TH_SYN|TH_FIN|TH_RST)) |
| 387 | tcpstat.tcps_sndctrl++; |
| 388 | else if (SEQ_GT(tp->snd_up, tp->snd_una)) |
| 389 | tcpstat.tcps_sndurg++; |
| 390 | else |
| 391 | tcpstat.tcps_sndwinup++; |
| 392 | |
| 393 | m = m_get(); |
| 394 | if (m == NULL) { |
| 395 | /* error = ENOBUFS; */ |
| 396 | error = 1; |
| 397 | goto out; |
| 398 | } |
| 399 | m->m_data += if_maxlinkhdr; |
| 400 | m->m_len = hdrlen; |
| 401 | } |
| 402 | |
| 403 | ti = mtod(m, struct tcpiphdr *); |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 404 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 405 | memcpy((caddr_t)ti, &tp->t_template, sizeof (struct tcpiphdr)); |
| 406 | |
| 407 | /* |
| 408 | * Fill in fields, remembering maximum advertised |
| 409 | * window for use in delaying messages about window sizes. |
| 410 | * If resending a FIN, be sure not to use a new sequence number. |
| 411 | */ |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 412 | if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 413 | tp->snd_nxt == tp->snd_max) |
| 414 | tp->snd_nxt--; |
| 415 | /* |
| 416 | * If we are doing retransmissions, then snd_nxt will |
| 417 | * not reflect the first unsent octet. For ACK only |
| 418 | * packets, we do not want the sequence number of the |
| 419 | * retransmitted packet, we want the sequence number |
| 420 | * of the next unsent octet. So, if there is no data |
| 421 | * (and no SYN or FIN), use snd_max instead of snd_nxt |
| 422 | * when filling in ti_seq. But if we are in persist |
| 423 | * state, snd_max might reflect one byte beyond the |
| 424 | * right edge of the window, so use snd_nxt in that |
| 425 | * case, since we know we aren't doing a retransmission. |
| 426 | * (retransmit and persist are mutually exclusive...) |
| 427 | */ |
| 428 | if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST]) |
| 429 | ti->ti_seq = htonl(tp->snd_nxt); |
| 430 | else |
| 431 | ti->ti_seq = htonl(tp->snd_max); |
| 432 | ti->ti_ack = htonl(tp->rcv_nxt); |
| 433 | if (optlen) { |
| 434 | memcpy((caddr_t)(ti + 1), (caddr_t)opt, optlen); |
| 435 | ti->ti_off = (sizeof (struct tcphdr) + optlen) >> 2; |
| 436 | } |
| 437 | ti->ti_flags = flags; |
| 438 | /* |
| 439 | * Calculate receive window. Don't shrink window, |
| 440 | * but avoid silly window syndrome. |
| 441 | */ |
| 442 | if (win < (long)(so->so_rcv.sb_datalen / 4) && win < (long)tp->t_maxseg) |
| 443 | win = 0; |
| 444 | if (win > (long)TCP_MAXWIN << tp->rcv_scale) |
| 445 | win = (long)TCP_MAXWIN << tp->rcv_scale; |
| 446 | if (win < (long)(tp->rcv_adv - tp->rcv_nxt)) |
| 447 | win = (long)(tp->rcv_adv - tp->rcv_nxt); |
| 448 | ti->ti_win = htons((u_int16_t) (win>>tp->rcv_scale)); |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 449 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 450 | if (SEQ_GT(tp->snd_up, tp->snd_una)) { |
| 451 | ti->ti_urp = htons((u_int16_t)(tp->snd_up - ntohl(ti->ti_seq))); |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 452 | #ifdef notdef |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 453 | if (SEQ_GT(tp->snd_up, tp->snd_nxt)) { |
| 454 | ti->ti_urp = htons((u_int16_t)(tp->snd_up - tp->snd_nxt)); |
| 455 | #endif |
| 456 | ti->ti_flags |= TH_URG; |
| 457 | } else |
| 458 | /* |
| 459 | * If no urgent pointer to send, then we pull |
| 460 | * the urgent pointer to the left edge of the send window |
| 461 | * so that it doesn't drift into the send window on sequence |
| 462 | * number wraparound. |
| 463 | */ |
| 464 | tp->snd_up = tp->snd_una; /* drag it along */ |
| 465 | |
| 466 | /* |
| 467 | * Put TCP length in extended header, and then |
| 468 | * checksum extended header and data. |
| 469 | */ |
| 470 | if (len + optlen) |
| 471 | ti->ti_len = htons((u_int16_t)(sizeof (struct tcphdr) + |
| 472 | optlen + len)); |
| 473 | ti->ti_sum = cksum(m, (int)(hdrlen + len)); |
| 474 | |
| 475 | /* |
| 476 | * In transmit state, time the transmission and arrange for |
| 477 | * the retransmit. In persist state, just set snd_max. |
| 478 | */ |
| 479 | if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) { |
| 480 | tcp_seq startseq = tp->snd_nxt; |
| 481 | |
| 482 | /* |
| 483 | * Advance snd_nxt over sequence space of this segment. |
| 484 | */ |
| 485 | if (flags & (TH_SYN|TH_FIN)) { |
| 486 | if (flags & TH_SYN) |
| 487 | tp->snd_nxt++; |
| 488 | if (flags & TH_FIN) { |
| 489 | tp->snd_nxt++; |
| 490 | tp->t_flags |= TF_SENTFIN; |
| 491 | } |
| 492 | } |
| 493 | tp->snd_nxt += len; |
| 494 | if (SEQ_GT(tp->snd_nxt, tp->snd_max)) { |
| 495 | tp->snd_max = tp->snd_nxt; |
| 496 | /* |
| 497 | * Time this transmission if not a retransmission and |
| 498 | * not currently timing anything. |
| 499 | */ |
| 500 | if (tp->t_rtt == 0) { |
| 501 | tp->t_rtt = 1; |
| 502 | tp->t_rtseq = startseq; |
| 503 | tcpstat.tcps_segstimed++; |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | /* |
| 508 | * Set retransmit timer if not currently set, |
| 509 | * and not doing an ack or a keep-alive probe. |
| 510 | * Initial value for retransmit timer is smoothed |
| 511 | * round-trip time + 2 * round-trip time variance. |
| 512 | * Initialize shift counter which is used for backoff |
| 513 | * of retransmit time. |
| 514 | */ |
| 515 | if (tp->t_timer[TCPT_REXMT] == 0 && |
| 516 | tp->snd_nxt != tp->snd_una) { |
| 517 | tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; |
| 518 | if (tp->t_timer[TCPT_PERSIST]) { |
| 519 | tp->t_timer[TCPT_PERSIST] = 0; |
| 520 | tp->t_rxtshift = 0; |
| 521 | } |
| 522 | } |
| 523 | } else |
| 524 | if (SEQ_GT(tp->snd_nxt + len, tp->snd_max)) |
| 525 | tp->snd_max = tp->snd_nxt + len; |
| 526 | |
| 527 | /* |
| 528 | * Fill in IP length and desired time to live and |
| 529 | * send to IP level. There should be a better way |
| 530 | * to handle ttl and tos; we could keep them in |
| 531 | * the template, but need a way to checksum without them. |
| 532 | */ |
| 533 | m->m_len = hdrlen + len; /* XXX Needed? m_len should be correct */ |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 534 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 535 | { |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 536 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 537 | ((struct ip *)ti)->ip_len = m->m_len; |
| 538 | |
| 539 | ((struct ip *)ti)->ip_ttl = ip_defttl; |
| 540 | ((struct ip *)ti)->ip_tos = so->so_iptos; |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 541 | |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 542 | /* #if BSD >= 43 */ |
| 543 | /* Don't do IP options... */ |
| 544 | /* error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route, |
| 545 | * so->so_options & SO_DONTROUTE, 0); |
| 546 | */ |
| 547 | error = ip_output(so, m); |
| 548 | |
| 549 | /* #else |
ths | 5fafdf2 | 2007-09-16 21:08:06 +0000 | [diff] [blame] | 550 | * error = ip_output(m, (struct mbuf *)0, &tp->t_inpcb->inp_route, |
bellard | f0cbd3e | 2004-04-22 00:10:48 +0000 | [diff] [blame] | 551 | * so->so_options & SO_DONTROUTE); |
| 552 | * #endif |
| 553 | */ |
| 554 | } |
| 555 | if (error) { |
| 556 | out: |
| 557 | /* if (error == ENOBUFS) { |
| 558 | * tcp_quench(tp->t_inpcb, 0); |
| 559 | * return (0); |
| 560 | * } |
| 561 | */ |
| 562 | /* if ((error == EHOSTUNREACH || error == ENETDOWN) |
| 563 | * && TCPS_HAVERCVDSYN(tp->t_state)) { |
| 564 | * tp->t_softerror = error; |
| 565 | * return (0); |
| 566 | * } |
| 567 | */ |
| 568 | return (error); |
| 569 | } |
| 570 | tcpstat.tcps_sndtotal++; |
| 571 | |
| 572 | /* |
| 573 | * Data sent (as far as we can tell). |
| 574 | * If this advertises a larger window than any other segment, |
| 575 | * then remember the size of the advertised window. |
| 576 | * Any pending ACK has now been sent. |
| 577 | */ |
| 578 | if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv)) |
| 579 | tp->rcv_adv = tp->rcv_nxt + win; |
| 580 | tp->last_ack_sent = tp->rcv_nxt; |
| 581 | tp->t_flags &= ~(TF_ACKNOW|TF_DELACK); |
| 582 | if (sendalot) |
| 583 | goto again; |
| 584 | |
| 585 | return (0); |
| 586 | } |
| 587 | |
| 588 | void |
| 589 | tcp_setpersist(tp) |
| 590 | register struct tcpcb *tp; |
| 591 | { |
| 592 | int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1; |
| 593 | |
| 594 | /* if (tp->t_timer[TCPT_REXMT]) |
| 595 | * panic("tcp_output REXMT"); |
| 596 | */ |
| 597 | /* |
| 598 | * Start/restart persistence timer. |
| 599 | */ |
| 600 | TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], |
| 601 | t * tcp_backoff[tp->t_rxtshift], |
| 602 | TCPTV_PERSMIN, TCPTV_PERSMAX); |
| 603 | if (tp->t_rxtshift < TCP_MAXRXTSHIFT) |
| 604 | tp->t_rxtshift++; |
| 605 | } |