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