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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. 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. ! 40: * ! 41: * Please read the file COPYRIGHT for the ! 42: * terms and conditions of the copyright. ! 43: */ ! 44: ! 45: #include <slirp.h> ! 46: ! 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, ! 60: TH_ACK, TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK, ! 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; ! 82: ! 83: DEBUG_CALL("tcp_output"); ! 84: DEBUG_ARG("tp = %lx", (long )tp); ! 85: ! 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]; ! 106: ! 107: DEBUG_MISC((dfd, " --- tcp_output flags = 0x%x\n",flags)); ! 108: ! 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: } ! 161: ! 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) { ! 203: /* ! 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++; ! 267: ! 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: } ! 305: ! 306: /* ! 307: * Send a timestamp and echo-reply if this is a SYN and our side ! 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; ! 325: ! 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; ! 359: ! 360: /* ! 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 *); ! 404: ! 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: */ ! 412: if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && ! 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)); ! 449: ! 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))); ! 452: #ifdef notdef ! 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 */ ! 534: ! 535: { ! 536: ! 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; ! 541: ! 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 ! 550: * error = ip_output(m, (struct mbuf *)0, &tp->t_inpcb->inp_route, ! 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: }
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