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gbeauche |
1.1 |
/* |
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* Copyright (c) 1982, 1986, 1988, 1990, 1993 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* This product includes software developed by the University of |
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* California, Berkeley and its contributors. |
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* 4. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* @(#)tcp_output.c 8.3 (Berkeley) 12/30/93 |
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* tcp_output.c,v 1.3 1994/09/15 10:36:55 davidg Exp |
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*/ |
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/* |
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* Changes and additions relating to SLiRP |
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* Copyright (c) 1995 Danny Gasparovski. |
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* |
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* Please read the file COPYRIGHT for the |
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* terms and conditions of the copyright. |
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*/ |
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#include <slirp.h> |
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/* |
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* Since this is only used in "stats socket", we give meaning |
| 49 |
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* names instead of the REAL names |
| 50 |
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*/ |
| 51 |
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char *tcpstates[] = { |
| 52 |
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/* "CLOSED", "LISTEN", "SYN_SENT", "SYN_RCVD", */ |
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"REDIRECT", "LISTEN", "SYN_SENT", "SYN_RCVD", |
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"ESTABLISHED", "CLOSE_WAIT", "FIN_WAIT_1", "CLOSING", |
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"LAST_ACK", "FIN_WAIT_2", "TIME_WAIT", |
| 56 |
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}; |
| 57 |
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| 58 |
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u_char tcp_outflags[TCP_NSTATES] = { |
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TH_RST|TH_ACK, 0, TH_SYN, TH_SYN|TH_ACK, |
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TH_ACK, TH_ACK, TH_FIN|TH_ACK, TH_FIN|TH_ACK, |
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TH_FIN|TH_ACK, TH_ACK, TH_ACK, |
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}; |
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#define MAX_TCPOPTLEN 32 /* max # bytes that go in options */ |
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/* |
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* Tcp output routine: figure out what should be sent and send it. |
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*/ |
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int |
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tcp_output(tp) |
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register struct tcpcb *tp; |
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{ |
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register struct socket *so = tp->t_socket; |
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register long len, win; |
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int off, flags, error; |
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register struct mbuf *m; |
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register struct tcpiphdr *ti; |
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u_char opt[MAX_TCPOPTLEN]; |
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unsigned optlen, hdrlen; |
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int idle, sendalot; |
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DEBUG_CALL("tcp_output"); |
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DEBUG_ARG("tp = %lx", (long )tp); |
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/* |
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* Determine length of data that should be transmitted, |
| 88 |
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* and flags that will be used. |
| 89 |
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* If there is some data or critical controls (SYN, RST) |
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* to send, then transmit; otherwise, investigate further. |
| 91 |
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*/ |
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idle = (tp->snd_max == tp->snd_una); |
| 93 |
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if (idle && tp->t_idle >= tp->t_rxtcur) |
| 94 |
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/* |
| 95 |
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* We have been idle for "a while" and no acks are |
| 96 |
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* expected to clock out any data we send -- |
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* slow start to get ack "clock" running again. |
| 98 |
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*/ |
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tp->snd_cwnd = tp->t_maxseg; |
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again: |
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sendalot = 0; |
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off = tp->snd_nxt - tp->snd_una; |
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win = min(tp->snd_wnd, tp->snd_cwnd); |
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flags = tcp_outflags[tp->t_state]; |
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DEBUG_MISC((dfd, " --- tcp_output flags = 0x%x\n",flags)); |
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| 109 |
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/* |
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* If in persist timeout with window of 0, send 1 byte. |
| 111 |
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* Otherwise, if window is small but nonzero |
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* and timer expired, we will send what we can |
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* and go to transmit state. |
| 114 |
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*/ |
| 115 |
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if (tp->t_force) { |
| 116 |
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if (win == 0) { |
| 117 |
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/* |
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* If we still have some data to send, then |
| 119 |
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* clear the FIN bit. Usually this would |
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* happen below when it realizes that we |
| 121 |
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* aren't sending all the data. However, |
| 122 |
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* if we have exactly 1 byte of unset data, |
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* then it won't clear the FIN bit below, |
| 124 |
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* and if we are in persist state, we wind |
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* up sending the packet without recording |
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* that we sent the FIN bit. |
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* |
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* We can't just blindly clear the FIN bit, |
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* because if we don't have any more data |
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* to send then the probe will be the FIN |
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* itself. |
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*/ |
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if (off < so->so_snd.sb_cc) |
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flags &= ~TH_FIN; |
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win = 1; |
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} else { |
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tp->t_timer[TCPT_PERSIST] = 0; |
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tp->t_rxtshift = 0; |
| 139 |
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} |
| 140 |
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} |
| 141 |
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| 142 |
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len = min(so->so_snd.sb_cc, win) - off; |
| 143 |
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| 144 |
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if (len < 0) { |
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/* |
| 146 |
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* If FIN has been sent but not acked, |
| 147 |
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* but we haven't been called to retransmit, |
| 148 |
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* len will be -1. Otherwise, window shrank |
| 149 |
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* after we sent into it. If window shrank to 0, |
| 150 |
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* cancel pending retransmit and pull snd_nxt |
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* back to (closed) window. We will enter persist |
| 152 |
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* state below. If the window didn't close completely, |
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* just wait for an ACK. |
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*/ |
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len = 0; |
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if (win == 0) { |
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tp->t_timer[TCPT_REXMT] = 0; |
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tp->snd_nxt = tp->snd_una; |
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} |
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} |
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if (len > tp->t_maxseg) { |
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len = tp->t_maxseg; |
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sendalot = 1; |
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} |
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if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) |
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flags &= ~TH_FIN; |
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win = sbspace(&so->so_rcv); |
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/* |
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* Sender silly window avoidance. If connection is idle |
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* and can send all data, a maximum segment, |
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* at least a maximum default-size segment do it, |
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* or are forced, do it; otherwise don't bother. |
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* If peer's buffer is tiny, then send |
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* when window is at least half open. |
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* If retransmitting (possibly after persist timer forced us |
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* to send into a small window), then must resend. |
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*/ |
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if (len) { |
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if (len == tp->t_maxseg) |
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goto send; |
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if ((1 || idle || tp->t_flags & TF_NODELAY) && |
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len + off >= so->so_snd.sb_cc) |
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goto send; |
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if (tp->t_force) |
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goto send; |
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if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) |
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goto send; |
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if (SEQ_LT(tp->snd_nxt, tp->snd_max)) |
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goto send; |
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} |
| 194 |
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| 195 |
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/* |
| 196 |
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* Compare available window to amount of window |
| 197 |
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* known to peer (as advertised window less |
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* next expected input). If the difference is at least two |
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* max size segments, or at least 50% of the maximum possible |
| 200 |
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* window, then want to send a window update to peer. |
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*/ |
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if (win > 0) { |
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/* |
| 204 |
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* "adv" is the amount we can increase the window, |
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* taking into account that we are limited by |
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* TCP_MAXWIN << tp->rcv_scale. |
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*/ |
| 208 |
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long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) - |
| 209 |
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(tp->rcv_adv - tp->rcv_nxt); |
| 210 |
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| 211 |
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if (adv >= (long) (2 * tp->t_maxseg)) |
| 212 |
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goto send; |
| 213 |
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if (2 * adv >= (long) so->so_rcv.sb_datalen) |
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goto send; |
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} |
| 216 |
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| 217 |
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/* |
| 218 |
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* Send if we owe peer an ACK. |
| 219 |
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*/ |
| 220 |
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if (tp->t_flags & TF_ACKNOW) |
| 221 |
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goto send; |
| 222 |
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if (flags & (TH_SYN|TH_RST)) |
| 223 |
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goto send; |
| 224 |
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if (SEQ_GT(tp->snd_up, tp->snd_una)) |
| 225 |
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goto send; |
| 226 |
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/* |
| 227 |
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* If our state indicates that FIN should be sent |
| 228 |
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* and we have not yet done so, or we're retransmitting the FIN, |
| 229 |
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* then we need to send. |
| 230 |
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*/ |
| 231 |
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if (flags & TH_FIN && |
| 232 |
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((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una)) |
| 233 |
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goto send; |
| 234 |
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| 235 |
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/* |
| 236 |
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* TCP window updates are not reliable, rather a polling protocol |
| 237 |
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* using ``persist'' packets is used to insure receipt of window |
| 238 |
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* updates. The three ``states'' for the output side are: |
| 239 |
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* idle not doing retransmits or persists |
| 240 |
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* persisting to move a small or zero window |
| 241 |
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* (re)transmitting and thereby not persisting |
| 242 |
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* |
| 243 |
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* tp->t_timer[TCPT_PERSIST] |
| 244 |
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* is set when we are in persist state. |
| 245 |
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* tp->t_force |
| 246 |
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* is set when we are called to send a persist packet. |
| 247 |
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* tp->t_timer[TCPT_REXMT] |
| 248 |
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* is set when we are retransmitting |
| 249 |
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* The output side is idle when both timers are zero. |
| 250 |
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* |
| 251 |
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* If send window is too small, there is data to transmit, and no |
| 252 |
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* retransmit or persist is pending, then go to persist state. |
| 253 |
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* If nothing happens soon, send when timer expires: |
| 254 |
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* if window is nonzero, transmit what we can, |
| 255 |
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* otherwise force out a byte. |
| 256 |
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*/ |
| 257 |
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if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 && |
| 258 |
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tp->t_timer[TCPT_PERSIST] == 0) { |
| 259 |
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tp->t_rxtshift = 0; |
| 260 |
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tcp_setpersist(tp); |
| 261 |
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} |
| 262 |
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| 263 |
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/* |
| 264 |
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* No reason to send a segment, just return. |
| 265 |
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*/ |
| 266 |
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tcpstat.tcps_didnuttin++; |
| 267 |
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| 268 |
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return (0); |
| 269 |
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| 270 |
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send: |
| 271 |
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/* |
| 272 |
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* Before ESTABLISHED, force sending of initial options |
| 273 |
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* unless TCP set not to do any options. |
| 274 |
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* NOTE: we assume that the IP/TCP header plus TCP options |
| 275 |
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* always fit in a single mbuf, leaving room for a maximum |
| 276 |
|
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* link header, i.e. |
| 277 |
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* max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN |
| 278 |
|
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*/ |
| 279 |
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optlen = 0; |
| 280 |
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hdrlen = sizeof (struct tcpiphdr); |
| 281 |
|
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if (flags & TH_SYN) { |
| 282 |
|
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tp->snd_nxt = tp->iss; |
| 283 |
|
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if ((tp->t_flags & TF_NOOPT) == 0) { |
| 284 |
|
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u_int16_t mss; |
| 285 |
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|
| 286 |
|
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opt[0] = TCPOPT_MAXSEG; |
| 287 |
|
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opt[1] = 4; |
| 288 |
|
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mss = htons((u_int16_t) tcp_mss(tp, 0)); |
| 289 |
|
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memcpy((caddr_t)(opt + 2), (caddr_t)&mss, sizeof(mss)); |
| 290 |
|
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optlen = 4; |
| 291 |
|
|
|
| 292 |
|
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/* if ((tp->t_flags & TF_REQ_SCALE) && |
| 293 |
|
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* ((flags & TH_ACK) == 0 || |
| 294 |
|
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* (tp->t_flags & TF_RCVD_SCALE))) { |
| 295 |
|
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* *((u_int32_t *) (opt + optlen)) = htonl( |
| 296 |
|
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* TCPOPT_NOP << 24 | |
| 297 |
|
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* TCPOPT_WINDOW << 16 | |
| 298 |
|
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* TCPOLEN_WINDOW << 8 | |
| 299 |
|
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* tp->request_r_scale); |
| 300 |
|
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* optlen += 4; |
| 301 |
|
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* } |
| 302 |
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*/ |
| 303 |
|
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} |
| 304 |
|
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} |
| 305 |
|
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|
| 306 |
|
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/* |
| 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 |
|
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*/ |
| 311 |
|
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/* if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && |
| 312 |
|
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* (flags & TH_RST) == 0 && |
| 313 |
|
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* ((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 |
|
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* |
| 317 |
|
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* / * Form timestamp option as shown in appendix A of RFC 1323. * / |
| 318 |
|
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* *lp++ = htonl(TCPOPT_TSTAMP_HDR); |
| 319 |
|
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* *lp++ = htonl(tcp_now); |
| 320 |
|
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* *lp = htonl(tp->ts_recent); |
| 321 |
|
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* optlen += TCPOLEN_TSTAMP_APPA; |
| 322 |
|
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* } |
| 323 |
|
|
*/ |
| 324 |
|
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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 |
|
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len = tp->t_maxseg - optlen; |
| 332 |
|
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sendalot = 1; |
| 333 |
|
|
} |
| 334 |
|
|
|
| 335 |
|
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/* |
| 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 |
|
|
} |
