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