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1 | f0cbd3ec | bellard | /*
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2 | f0cbd3ec | bellard | * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994
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3 | f0cbd3ec | bellard | * The Regents of the University of California. All rights reserved.
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4 | f0cbd3ec | bellard | *
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5 | f0cbd3ec | bellard | * Redistribution and use in source and binary forms, with or without
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6 | f0cbd3ec | bellard | * modification, are permitted provided that the following conditions
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7 | f0cbd3ec | bellard | * are met:
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8 | f0cbd3ec | bellard | * 1. Redistributions of source code must retain the above copyright
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9 | f0cbd3ec | bellard | * notice, this list of conditions and the following disclaimer.
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10 | f0cbd3ec | bellard | * 2. Redistributions in binary form must reproduce the above copyright
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11 | f0cbd3ec | bellard | * notice, this list of conditions and the following disclaimer in the
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12 | f0cbd3ec | bellard | * documentation and/or other materials provided with the distribution.
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13 | 2f5f8996 | aliguori | * 3. Neither the name of the University nor the names of its contributors
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14 | f0cbd3ec | bellard | * may be used to endorse or promote products derived from this software
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15 | f0cbd3ec | bellard | * without specific prior written permission.
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16 | f0cbd3ec | bellard | *
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17 | f0cbd3ec | bellard | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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18 | f0cbd3ec | bellard | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | f0cbd3ec | bellard | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | f0cbd3ec | bellard | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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21 | f0cbd3ec | bellard | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | f0cbd3ec | bellard | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | f0cbd3ec | bellard | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | f0cbd3ec | bellard | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | f0cbd3ec | bellard | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | f0cbd3ec | bellard | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | f0cbd3ec | bellard | * SUCH DAMAGE.
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28 | f0cbd3ec | bellard | *
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29 | f0cbd3ec | bellard | * @(#)tcp_input.c 8.5 (Berkeley) 4/10/94
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30 | f0cbd3ec | bellard | * tcp_input.c,v 1.10 1994/10/13 18:36:32 wollman Exp
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31 | f0cbd3ec | bellard | */
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32 | f0cbd3ec | bellard | |
33 | f0cbd3ec | bellard | /*
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34 | f0cbd3ec | bellard | * Changes and additions relating to SLiRP
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35 | f0cbd3ec | bellard | * Copyright (c) 1995 Danny Gasparovski.
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36 | 5fafdf24 | ths | *
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37 | 5fafdf24 | ths | * Please read the file COPYRIGHT for the
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38 | f0cbd3ec | bellard | * terms and conditions of the copyright.
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39 | f0cbd3ec | bellard | */
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40 | f0cbd3ec | bellard | |
41 | f0cbd3ec | bellard | #include <slirp.h> |
42 | f0cbd3ec | bellard | #include "ip_icmp.h" |
43 | f0cbd3ec | bellard | |
44 | 9634d903 | blueswir1 | #define TCPREXMTTHRESH 3 |
45 | f0cbd3ec | bellard | |
46 | f0cbd3ec | bellard | #define TCP_PAWS_IDLE (24 * 24 * 60 * 60 * PR_SLOWHZ) |
47 | f0cbd3ec | bellard | |
48 | f0cbd3ec | bellard | /* for modulo comparisons of timestamps */
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49 | f0cbd3ec | bellard | #define TSTMP_LT(a,b) ((int)((a)-(b)) < 0) |
50 | f0cbd3ec | bellard | #define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0) |
51 | f0cbd3ec | bellard | |
52 | f0cbd3ec | bellard | /*
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53 | f0cbd3ec | bellard | * Insert segment ti into reassembly queue of tcp with
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54 | f0cbd3ec | bellard | * control block tp. Return TH_FIN if reassembly now includes
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55 | f0cbd3ec | bellard | * a segment with FIN. The macro form does the common case inline
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56 | f0cbd3ec | bellard | * (segment is the next to be received on an established connection,
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57 | f0cbd3ec | bellard | * and the queue is empty), avoiding linkage into and removal
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58 | f0cbd3ec | bellard | * from the queue and repetition of various conversions.
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59 | f0cbd3ec | bellard | * Set DELACK for segments received in order, but ack immediately
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60 | f0cbd3ec | bellard | * when segments are out of order (so fast retransmit can work).
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61 | f0cbd3ec | bellard | */
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62 | f0cbd3ec | bellard | #ifdef TCP_ACK_HACK
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63 | f0cbd3ec | bellard | #define TCP_REASS(tp, ti, m, so, flags) {\
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64 | f0cbd3ec | bellard | if ((ti)->ti_seq == (tp)->rcv_nxt && \
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65 | 429d0a3d | blueswir1 | tcpfrag_list_empty(tp) && \ |
66 | f0cbd3ec | bellard | (tp)->t_state == TCPS_ESTABLISHED) {\ |
67 | f0cbd3ec | bellard | if (ti->ti_flags & TH_PUSH) \
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68 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; \ |
69 | f0cbd3ec | bellard | else \
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70 | f0cbd3ec | bellard | tp->t_flags |= TF_DELACK; \ |
71 | f0cbd3ec | bellard | (tp)->rcv_nxt += (ti)->ti_len; \ |
72 | f0cbd3ec | bellard | flags = (ti)->ti_flags & TH_FIN; \ |
73 | f0cbd3ec | bellard | if (so->so_emu) { \
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74 | f0cbd3ec | bellard | if (tcp_emu((so),(m))) sbappend((so), (m)); \
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75 | f0cbd3ec | bellard | } else \
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76 | f0cbd3ec | bellard | sbappend((so), (m)); \ |
77 | f0cbd3ec | bellard | } else {\
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78 | f0cbd3ec | bellard | (flags) = tcp_reass((tp), (ti), (m)); \ |
79 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; \ |
80 | f0cbd3ec | bellard | } \ |
81 | f0cbd3ec | bellard | } |
82 | f0cbd3ec | bellard | #else
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83 | f0cbd3ec | bellard | #define TCP_REASS(tp, ti, m, so, flags) { \
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84 | f0cbd3ec | bellard | if ((ti)->ti_seq == (tp)->rcv_nxt && \
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85 | 429d0a3d | blueswir1 | tcpfrag_list_empty(tp) && \ |
86 | f0cbd3ec | bellard | (tp)->t_state == TCPS_ESTABLISHED) { \ |
87 | f0cbd3ec | bellard | tp->t_flags |= TF_DELACK; \ |
88 | f0cbd3ec | bellard | (tp)->rcv_nxt += (ti)->ti_len; \ |
89 | f0cbd3ec | bellard | flags = (ti)->ti_flags & TH_FIN; \ |
90 | f0cbd3ec | bellard | if (so->so_emu) { \
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91 | f0cbd3ec | bellard | if (tcp_emu((so),(m))) sbappend(so, (m)); \
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92 | f0cbd3ec | bellard | } else \
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93 | f0cbd3ec | bellard | sbappend((so), (m)); \ |
94 | f0cbd3ec | bellard | } else { \
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95 | f0cbd3ec | bellard | (flags) = tcp_reass((tp), (ti), (m)); \ |
96 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; \ |
97 | f0cbd3ec | bellard | } \ |
98 | f0cbd3ec | bellard | } |
99 | f0cbd3ec | bellard | #endif
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100 | 9634d903 | blueswir1 | static void tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt, |
101 | 9634d903 | blueswir1 | struct tcpiphdr *ti);
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102 | 9634d903 | blueswir1 | static void tcp_xmit_timer(register struct tcpcb *tp, int rtt); |
103 | f0cbd3ec | bellard | |
104 | 9634d903 | blueswir1 | static int |
105 | 9634d903 | blueswir1 | tcp_reass(register struct tcpcb *tp, register struct tcpiphdr *ti, |
106 | 9634d903 | blueswir1 | struct mbuf *m)
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107 | f0cbd3ec | bellard | { |
108 | f0cbd3ec | bellard | register struct tcpiphdr *q; |
109 | f0cbd3ec | bellard | struct socket *so = tp->t_socket;
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110 | f0cbd3ec | bellard | int flags;
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111 | 5fafdf24 | ths | |
112 | f0cbd3ec | bellard | /*
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113 | 511d2b14 | blueswir1 | * Call with ti==NULL after become established to
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114 | f0cbd3ec | bellard | * force pre-ESTABLISHED data up to user socket.
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115 | f0cbd3ec | bellard | */
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116 | 511d2b14 | blueswir1 | if (ti == NULL) |
117 | f0cbd3ec | bellard | goto present;
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118 | f0cbd3ec | bellard | |
119 | f0cbd3ec | bellard | /*
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120 | f0cbd3ec | bellard | * Find a segment which begins after this one does.
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121 | f0cbd3ec | bellard | */
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122 | 429d0a3d | blueswir1 | for (q = tcpfrag_list_first(tp); !tcpfrag_list_end(q, tp);
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123 | 429d0a3d | blueswir1 | q = tcpiphdr_next(q)) |
124 | f0cbd3ec | bellard | if (SEQ_GT(q->ti_seq, ti->ti_seq))
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125 | f0cbd3ec | bellard | break;
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126 | f0cbd3ec | bellard | |
127 | f0cbd3ec | bellard | /*
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128 | f0cbd3ec | bellard | * If there is a preceding segment, it may provide some of
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129 | f0cbd3ec | bellard | * our data already. If so, drop the data from the incoming
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130 | f0cbd3ec | bellard | * segment. If it provides all of our data, drop us.
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131 | f0cbd3ec | bellard | */
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132 | 429d0a3d | blueswir1 | if (!tcpfrag_list_end(tcpiphdr_prev(q), tp)) {
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133 | f0cbd3ec | bellard | register int i; |
134 | 429d0a3d | blueswir1 | q = tcpiphdr_prev(q); |
135 | f0cbd3ec | bellard | /* conversion to int (in i) handles seq wraparound */
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136 | f0cbd3ec | bellard | i = q->ti_seq + q->ti_len - ti->ti_seq; |
137 | f0cbd3ec | bellard | if (i > 0) { |
138 | f0cbd3ec | bellard | if (i >= ti->ti_len) {
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139 | f0cbd3ec | bellard | m_freem(m); |
140 | f0cbd3ec | bellard | /*
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141 | f0cbd3ec | bellard | * Try to present any queued data
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142 | f0cbd3ec | bellard | * at the left window edge to the user.
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143 | f0cbd3ec | bellard | * This is needed after the 3-WHS
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144 | f0cbd3ec | bellard | * completes.
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145 | f0cbd3ec | bellard | */
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146 | f0cbd3ec | bellard | goto present; /* ??? */ |
147 | f0cbd3ec | bellard | } |
148 | f0cbd3ec | bellard | m_adj(m, i); |
149 | f0cbd3ec | bellard | ti->ti_len -= i; |
150 | f0cbd3ec | bellard | ti->ti_seq += i; |
151 | f0cbd3ec | bellard | } |
152 | 429d0a3d | blueswir1 | q = tcpiphdr_next(q); |
153 | f0cbd3ec | bellard | } |
154 | 429d0a3d | blueswir1 | ti->ti_mbuf = m; |
155 | f0cbd3ec | bellard | |
156 | f0cbd3ec | bellard | /*
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157 | f0cbd3ec | bellard | * While we overlap succeeding segments trim them or,
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158 | f0cbd3ec | bellard | * if they are completely covered, dequeue them.
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159 | f0cbd3ec | bellard | */
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160 | 429d0a3d | blueswir1 | while (!tcpfrag_list_end(q, tp)) {
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161 | f0cbd3ec | bellard | register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq; |
162 | f0cbd3ec | bellard | if (i <= 0) |
163 | f0cbd3ec | bellard | break;
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164 | f0cbd3ec | bellard | if (i < q->ti_len) {
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165 | f0cbd3ec | bellard | q->ti_seq += i; |
166 | f0cbd3ec | bellard | q->ti_len -= i; |
167 | 429d0a3d | blueswir1 | m_adj(q->ti_mbuf, i); |
168 | f0cbd3ec | bellard | break;
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169 | f0cbd3ec | bellard | } |
170 | 429d0a3d | blueswir1 | q = tcpiphdr_next(q); |
171 | 429d0a3d | blueswir1 | m = tcpiphdr_prev(q)->ti_mbuf; |
172 | 429d0a3d | blueswir1 | remque(tcpiphdr2qlink(tcpiphdr_prev(q))); |
173 | f0cbd3ec | bellard | m_freem(m); |
174 | f0cbd3ec | bellard | } |
175 | f0cbd3ec | bellard | |
176 | f0cbd3ec | bellard | /*
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177 | f0cbd3ec | bellard | * Stick new segment in its place.
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178 | f0cbd3ec | bellard | */
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179 | 429d0a3d | blueswir1 | insque(tcpiphdr2qlink(ti), tcpiphdr2qlink(tcpiphdr_prev(q))); |
180 | f0cbd3ec | bellard | |
181 | f0cbd3ec | bellard | present:
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182 | f0cbd3ec | bellard | /*
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183 | f0cbd3ec | bellard | * Present data to user, advancing rcv_nxt through
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184 | f0cbd3ec | bellard | * completed sequence space.
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185 | f0cbd3ec | bellard | */
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186 | f0cbd3ec | bellard | if (!TCPS_HAVEESTABLISHED(tp->t_state))
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187 | f0cbd3ec | bellard | return (0); |
188 | 429d0a3d | blueswir1 | ti = tcpfrag_list_first(tp); |
189 | 429d0a3d | blueswir1 | if (tcpfrag_list_end(ti, tp) || ti->ti_seq != tp->rcv_nxt)
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190 | f0cbd3ec | bellard | return (0); |
191 | f0cbd3ec | bellard | if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)
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192 | f0cbd3ec | bellard | return (0); |
193 | f0cbd3ec | bellard | do {
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194 | f0cbd3ec | bellard | tp->rcv_nxt += ti->ti_len; |
195 | f0cbd3ec | bellard | flags = ti->ti_flags & TH_FIN; |
196 | 429d0a3d | blueswir1 | remque(tcpiphdr2qlink(ti)); |
197 | 429d0a3d | blueswir1 | m = ti->ti_mbuf; |
198 | 429d0a3d | blueswir1 | ti = tcpiphdr_next(ti); |
199 | f0cbd3ec | bellard | if (so->so_state & SS_FCANTSENDMORE)
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200 | f0cbd3ec | bellard | m_freem(m); |
201 | f0cbd3ec | bellard | else {
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202 | f0cbd3ec | bellard | if (so->so_emu) {
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203 | f0cbd3ec | bellard | if (tcp_emu(so,m)) sbappend(so, m);
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204 | f0cbd3ec | bellard | } else
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205 | f0cbd3ec | bellard | sbappend(so, m); |
206 | f0cbd3ec | bellard | } |
207 | f0cbd3ec | bellard | } while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt); |
208 | f0cbd3ec | bellard | return (flags);
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209 | f0cbd3ec | bellard | } |
210 | f0cbd3ec | bellard | |
211 | f0cbd3ec | bellard | /*
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212 | f0cbd3ec | bellard | * TCP input routine, follows pages 65-76 of the
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213 | f0cbd3ec | bellard | * protocol specification dated September, 1981 very closely.
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214 | f0cbd3ec | bellard | */
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215 | f0cbd3ec | bellard | void
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216 | 511d2b14 | blueswir1 | tcp_input(struct mbuf *m, int iphlen, struct socket *inso) |
217 | f0cbd3ec | bellard | { |
218 | f0cbd3ec | bellard | struct ip save_ip, *ip;
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219 | f0cbd3ec | bellard | register struct tcpiphdr *ti; |
220 | f0cbd3ec | bellard | caddr_t optp = NULL;
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221 | f0cbd3ec | bellard | int optlen = 0; |
222 | f0cbd3ec | bellard | int len, tlen, off;
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223 | 511d2b14 | blueswir1 | register struct tcpcb *tp = NULL; |
224 | f0cbd3ec | bellard | register int tiflags; |
225 | 511d2b14 | blueswir1 | struct socket *so = NULL; |
226 | f0cbd3ec | bellard | int todrop, acked, ourfinisacked, needoutput = 0; |
227 | f0cbd3ec | bellard | int iss = 0; |
228 | f0cbd3ec | bellard | u_long tiwin; |
229 | f0cbd3ec | bellard | int ret;
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230 | a9ba3a85 | aliguori | struct ex_list *ex_ptr;
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231 | 460fec67 | Jan Kiszka | Slirp *slirp; |
232 | f0cbd3ec | bellard | |
233 | f0cbd3ec | bellard | DEBUG_CALL("tcp_input");
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234 | 5fafdf24 | ths | DEBUG_ARGS((dfd," m = %8lx iphlen = %2d inso = %lx\n",
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235 | f0cbd3ec | bellard | (long )m, iphlen, (long )inso )); |
236 | 5fafdf24 | ths | |
237 | f0cbd3ec | bellard | /*
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238 | f0cbd3ec | bellard | * If called with m == 0, then we're continuing the connect
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239 | f0cbd3ec | bellard | */
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240 | f0cbd3ec | bellard | if (m == NULL) { |
241 | f0cbd3ec | bellard | so = inso; |
242 | 460fec67 | Jan Kiszka | slirp = so->slirp; |
243 | 3b46e624 | ths | |
244 | f0cbd3ec | bellard | /* Re-set a few variables */
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245 | f0cbd3ec | bellard | tp = sototcpcb(so); |
246 | f0cbd3ec | bellard | m = so->so_m; |
247 | 511d2b14 | blueswir1 | so->so_m = NULL;
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248 | f0cbd3ec | bellard | ti = so->so_ti; |
249 | f0cbd3ec | bellard | tiwin = ti->ti_win; |
250 | f0cbd3ec | bellard | tiflags = ti->ti_flags; |
251 | 3b46e624 | ths | |
252 | f0cbd3ec | bellard | goto cont_conn;
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253 | f0cbd3ec | bellard | } |
254 | 460fec67 | Jan Kiszka | slirp = m->slirp; |
255 | 5fafdf24 | ths | |
256 | f0cbd3ec | bellard | /*
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257 | f0cbd3ec | bellard | * Get IP and TCP header together in first mbuf.
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258 | f0cbd3ec | bellard | * Note: IP leaves IP header in first mbuf.
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259 | f0cbd3ec | bellard | */
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260 | f0cbd3ec | bellard | ti = mtod(m, struct tcpiphdr *);
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261 | f0cbd3ec | bellard | if (iphlen > sizeof(struct ip )) { |
262 | f0cbd3ec | bellard | ip_stripoptions(m, (struct mbuf *)0); |
263 | f0cbd3ec | bellard | iphlen=sizeof(struct ip ); |
264 | f0cbd3ec | bellard | } |
265 | f0cbd3ec | bellard | /* XXX Check if too short */
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266 | 5fafdf24 | ths | |
267 | f0cbd3ec | bellard | |
268 | f0cbd3ec | bellard | /*
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269 | f0cbd3ec | bellard | * Save a copy of the IP header in case we want restore it
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270 | f0cbd3ec | bellard | * for sending an ICMP error message in response.
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271 | f0cbd3ec | bellard | */
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272 | f0cbd3ec | bellard | ip=mtod(m, struct ip *);
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273 | 5fafdf24 | ths | save_ip = *ip; |
274 | f0cbd3ec | bellard | save_ip.ip_len+= iphlen; |
275 | f0cbd3ec | bellard | |
276 | f0cbd3ec | bellard | /*
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277 | f0cbd3ec | bellard | * Checksum extended TCP header and data.
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278 | f0cbd3ec | bellard | */
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279 | f0cbd3ec | bellard | tlen = ((struct ip *)ti)->ip_len;
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280 | 511d2b14 | blueswir1 | tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
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281 | 511d2b14 | blueswir1 | memset(&ti->ti_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr)); |
282 | f0cbd3ec | bellard | ti->ti_x1 = 0;
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283 | f0cbd3ec | bellard | ti->ti_len = htons((u_int16_t)tlen); |
284 | f0cbd3ec | bellard | len = sizeof(struct ip ) + tlen; |
285 | f0cbd3ec | bellard | if(cksum(m, len)) {
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286 | f0cbd3ec | bellard | goto drop;
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287 | f0cbd3ec | bellard | } |
288 | f0cbd3ec | bellard | |
289 | f0cbd3ec | bellard | /*
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290 | f0cbd3ec | bellard | * Check that TCP offset makes sense,
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291 | f0cbd3ec | bellard | * pull out TCP options and adjust length. XXX
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292 | f0cbd3ec | bellard | */
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293 | f0cbd3ec | bellard | off = ti->ti_off << 2;
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294 | f0cbd3ec | bellard | if (off < sizeof (struct tcphdr) || off > tlen) { |
295 | f0cbd3ec | bellard | goto drop;
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296 | f0cbd3ec | bellard | } |
297 | f0cbd3ec | bellard | tlen -= off; |
298 | f0cbd3ec | bellard | ti->ti_len = tlen; |
299 | f0cbd3ec | bellard | if (off > sizeof (struct tcphdr)) { |
300 | f0cbd3ec | bellard | optlen = off - sizeof (struct tcphdr); |
301 | f0cbd3ec | bellard | optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr); |
302 | f0cbd3ec | bellard | } |
303 | f0cbd3ec | bellard | tiflags = ti->ti_flags; |
304 | 5fafdf24 | ths | |
305 | f0cbd3ec | bellard | /*
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306 | f0cbd3ec | bellard | * Convert TCP protocol specific fields to host format.
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307 | f0cbd3ec | bellard | */
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308 | f0cbd3ec | bellard | NTOHL(ti->ti_seq); |
309 | f0cbd3ec | bellard | NTOHL(ti->ti_ack); |
310 | f0cbd3ec | bellard | NTOHS(ti->ti_win); |
311 | f0cbd3ec | bellard | NTOHS(ti->ti_urp); |
312 | f0cbd3ec | bellard | |
313 | f0cbd3ec | bellard | /*
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314 | f0cbd3ec | bellard | * Drop TCP, IP headers and TCP options.
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315 | f0cbd3ec | bellard | */
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316 | f0cbd3ec | bellard | m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr); |
317 | f0cbd3ec | bellard | m->m_len -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr); |
318 | 5fafdf24 | ths | |
319 | 460fec67 | Jan Kiszka | if (slirp->restricted) {
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320 | 460fec67 | Jan Kiszka | for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
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321 | a9ba3a85 | aliguori | if (ex_ptr->ex_fport == ti->ti_dport &&
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322 | a13a4126 | Jan Kiszka | ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) { |
323 | a9ba3a85 | aliguori | break;
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324 | a13a4126 | Jan Kiszka | } |
325 | a13a4126 | Jan Kiszka | } |
326 | a9ba3a85 | aliguori | if (!ex_ptr)
|
327 | a9ba3a85 | aliguori | goto drop;
|
328 | a9ba3a85 | aliguori | } |
329 | f0cbd3ec | bellard | /*
|
330 | f0cbd3ec | bellard | * Locate pcb for segment.
|
331 | f0cbd3ec | bellard | */
|
332 | f0cbd3ec | bellard | findso:
|
333 | 460fec67 | Jan Kiszka | so = slirp->tcp_last_so; |
334 | f0cbd3ec | bellard | if (so->so_fport != ti->ti_dport ||
|
335 | f0cbd3ec | bellard | so->so_lport != ti->ti_sport || |
336 | f0cbd3ec | bellard | so->so_laddr.s_addr != ti->ti_src.s_addr || |
337 | f0cbd3ec | bellard | so->so_faddr.s_addr != ti->ti_dst.s_addr) { |
338 | 460fec67 | Jan Kiszka | so = solookup(&slirp->tcb, ti->ti_src, ti->ti_sport, |
339 | f0cbd3ec | bellard | ti->ti_dst, ti->ti_dport); |
340 | f0cbd3ec | bellard | if (so)
|
341 | 460fec67 | Jan Kiszka | slirp->tcp_last_so = so; |
342 | f0cbd3ec | bellard | } |
343 | f0cbd3ec | bellard | |
344 | f0cbd3ec | bellard | /*
|
345 | f0cbd3ec | bellard | * If the state is CLOSED (i.e., TCB does not exist) then
|
346 | f0cbd3ec | bellard | * all data in the incoming segment is discarded.
|
347 | f0cbd3ec | bellard | * If the TCB exists but is in CLOSED state, it is embryonic,
|
348 | f0cbd3ec | bellard | * but should either do a listen or a connect soon.
|
349 | f0cbd3ec | bellard | *
|
350 | f0cbd3ec | bellard | * state == CLOSED means we've done socreate() but haven't
|
351 | 5fafdf24 | ths | * attached it to a protocol yet...
|
352 | 5fafdf24 | ths | *
|
353 | f0cbd3ec | bellard | * XXX If a TCB does not exist, and the TH_SYN flag is
|
354 | f0cbd3ec | bellard | * the only flag set, then create a session, mark it
|
355 | f0cbd3ec | bellard | * as if it was LISTENING, and continue...
|
356 | f0cbd3ec | bellard | */
|
357 | 511d2b14 | blueswir1 | if (so == NULL) { |
358 | f0cbd3ec | bellard | if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
|
359 | f0cbd3ec | bellard | goto dropwithreset;
|
360 | 3b46e624 | ths | |
361 | 460fec67 | Jan Kiszka | if ((so = socreate(slirp)) == NULL) |
362 | f0cbd3ec | bellard | goto dropwithreset;
|
363 | f0cbd3ec | bellard | if (tcp_attach(so) < 0) { |
364 | f0cbd3ec | bellard | free(so); /* Not sofree (if it failed, it's not insqued) */
|
365 | f0cbd3ec | bellard | goto dropwithreset;
|
366 | f0cbd3ec | bellard | } |
367 | 3b46e624 | ths | |
368 | 9634d903 | blueswir1 | sbreserve(&so->so_snd, TCP_SNDSPACE); |
369 | 9634d903 | blueswir1 | sbreserve(&so->so_rcv, TCP_RCVSPACE); |
370 | 3b46e624 | ths | |
371 | f0cbd3ec | bellard | so->so_laddr = ti->ti_src; |
372 | f0cbd3ec | bellard | so->so_lport = ti->ti_sport; |
373 | f0cbd3ec | bellard | so->so_faddr = ti->ti_dst; |
374 | f0cbd3ec | bellard | so->so_fport = ti->ti_dport; |
375 | 3b46e624 | ths | |
376 | f0cbd3ec | bellard | if ((so->so_iptos = tcp_tos(so)) == 0) |
377 | f0cbd3ec | bellard | so->so_iptos = ((struct ip *)ti)->ip_tos;
|
378 | 3b46e624 | ths | |
379 | f0cbd3ec | bellard | tp = sototcpcb(so); |
380 | f0cbd3ec | bellard | tp->t_state = TCPS_LISTEN; |
381 | f0cbd3ec | bellard | } |
382 | 3b46e624 | ths | |
383 | f0cbd3ec | bellard | /*
|
384 | f0cbd3ec | bellard | * If this is a still-connecting socket, this probably
|
385 | f0cbd3ec | bellard | * a retransmit of the SYN. Whether it's a retransmit SYN
|
386 | f0cbd3ec | bellard | * or something else, we nuke it.
|
387 | f0cbd3ec | bellard | */
|
388 | f0cbd3ec | bellard | if (so->so_state & SS_ISFCONNECTING)
|
389 | f0cbd3ec | bellard | goto drop;
|
390 | f0cbd3ec | bellard | |
391 | f0cbd3ec | bellard | tp = sototcpcb(so); |
392 | 5fafdf24 | ths | |
393 | f0cbd3ec | bellard | /* XXX Should never fail */
|
394 | 511d2b14 | blueswir1 | if (tp == NULL) |
395 | f0cbd3ec | bellard | goto dropwithreset;
|
396 | f0cbd3ec | bellard | if (tp->t_state == TCPS_CLOSED)
|
397 | f0cbd3ec | bellard | goto drop;
|
398 | 5fafdf24 | ths | |
399 | 0d62c4cf | Jan Kiszka | tiwin = ti->ti_win; |
400 | f0cbd3ec | bellard | |
401 | f0cbd3ec | bellard | /*
|
402 | f0cbd3ec | bellard | * Segment received on connection.
|
403 | f0cbd3ec | bellard | * Reset idle time and keep-alive timer.
|
404 | f0cbd3ec | bellard | */
|
405 | f0cbd3ec | bellard | tp->t_idle = 0;
|
406 | 9634d903 | blueswir1 | if (SO_OPTIONS)
|
407 | 9634d903 | blueswir1 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEPINTVL; |
408 | f0cbd3ec | bellard | else
|
409 | 9634d903 | blueswir1 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_IDLE; |
410 | f0cbd3ec | bellard | |
411 | f0cbd3ec | bellard | /*
|
412 | f0cbd3ec | bellard | * Process options if not in LISTEN state,
|
413 | f0cbd3ec | bellard | * else do it below (after getting remote address).
|
414 | f0cbd3ec | bellard | */
|
415 | f0cbd3ec | bellard | if (optp && tp->t_state != TCPS_LISTEN)
|
416 | 5fafdf24 | ths | tcp_dooptions(tp, (u_char *)optp, optlen, ti); |
417 | f0cbd3ec | bellard | |
418 | 5fafdf24 | ths | /*
|
419 | f0cbd3ec | bellard | * Header prediction: check for the two common cases
|
420 | f0cbd3ec | bellard | * of a uni-directional data xfer. If the packet has
|
421 | f0cbd3ec | bellard | * no control flags, is in-sequence, the window didn't
|
422 | f0cbd3ec | bellard | * change and we're not retransmitting, it's a
|
423 | f0cbd3ec | bellard | * candidate. If the length is zero and the ack moved
|
424 | f0cbd3ec | bellard | * forward, we're the sender side of the xfer. Just
|
425 | f0cbd3ec | bellard | * free the data acked & wake any higher level process
|
426 | f0cbd3ec | bellard | * that was blocked waiting for space. If the length
|
427 | f0cbd3ec | bellard | * is non-zero and the ack didn't move, we're the
|
428 | f0cbd3ec | bellard | * receiver side. If we're getting packets in-order
|
429 | f0cbd3ec | bellard | * (the reassembly queue is empty), add the data to
|
430 | f0cbd3ec | bellard | * the socket buffer and note that we need a delayed ack.
|
431 | f0cbd3ec | bellard | *
|
432 | f0cbd3ec | bellard | * XXX Some of these tests are not needed
|
433 | f0cbd3ec | bellard | * eg: the tiwin == tp->snd_wnd prevents many more
|
434 | f0cbd3ec | bellard | * predictions.. with no *real* advantage..
|
435 | f0cbd3ec | bellard | */
|
436 | f0cbd3ec | bellard | if (tp->t_state == TCPS_ESTABLISHED &&
|
437 | f0cbd3ec | bellard | (tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK && |
438 | f0cbd3ec | bellard | ti->ti_seq == tp->rcv_nxt && |
439 | f0cbd3ec | bellard | tiwin && tiwin == tp->snd_wnd && |
440 | f0cbd3ec | bellard | tp->snd_nxt == tp->snd_max) { |
441 | f0cbd3ec | bellard | if (ti->ti_len == 0) { |
442 | f0cbd3ec | bellard | if (SEQ_GT(ti->ti_ack, tp->snd_una) &&
|
443 | f0cbd3ec | bellard | SEQ_LEQ(ti->ti_ack, tp->snd_max) && |
444 | f0cbd3ec | bellard | tp->snd_cwnd >= tp->snd_wnd) { |
445 | f0cbd3ec | bellard | /*
|
446 | f0cbd3ec | bellard | * this is a pure ack for outstanding data.
|
447 | f0cbd3ec | bellard | */
|
448 | 0d62c4cf | Jan Kiszka | if (tp->t_rtt &&
|
449 | 0d62c4cf | Jan Kiszka | SEQ_GT(ti->ti_ack, tp->t_rtseq)) |
450 | f0cbd3ec | bellard | tcp_xmit_timer(tp, tp->t_rtt); |
451 | f0cbd3ec | bellard | acked = ti->ti_ack - tp->snd_una; |
452 | f0cbd3ec | bellard | sbdrop(&so->so_snd, acked); |
453 | f0cbd3ec | bellard | tp->snd_una = ti->ti_ack; |
454 | f0cbd3ec | bellard | m_freem(m); |
455 | f0cbd3ec | bellard | |
456 | f0cbd3ec | bellard | /*
|
457 | f0cbd3ec | bellard | * If all outstanding data are acked, stop
|
458 | f0cbd3ec | bellard | * retransmit timer, otherwise restart timer
|
459 | f0cbd3ec | bellard | * using current (possibly backed-off) value.
|
460 | f0cbd3ec | bellard | * If process is waiting for space,
|
461 | f0cbd3ec | bellard | * wakeup/selwakeup/signal. If data
|
462 | f0cbd3ec | bellard | * are ready to send, let tcp_output
|
463 | f0cbd3ec | bellard | * decide between more output or persist.
|
464 | f0cbd3ec | bellard | */
|
465 | f0cbd3ec | bellard | if (tp->snd_una == tp->snd_max)
|
466 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = 0;
|
467 | f0cbd3ec | bellard | else if (tp->t_timer[TCPT_PERSIST] == 0) |
468 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; |
469 | f0cbd3ec | bellard | |
470 | 5fafdf24 | ths | /*
|
471 | f0cbd3ec | bellard | * This is called because sowwakeup might have
|
472 | f0cbd3ec | bellard | * put data into so_snd. Since we don't so sowwakeup,
|
473 | f0cbd3ec | bellard | * we don't need this.. XXX???
|
474 | f0cbd3ec | bellard | */
|
475 | f0cbd3ec | bellard | if (so->so_snd.sb_cc)
|
476 | f0cbd3ec | bellard | (void) tcp_output(tp);
|
477 | f0cbd3ec | bellard | |
478 | f0cbd3ec | bellard | return;
|
479 | f0cbd3ec | bellard | } |
480 | f0cbd3ec | bellard | } else if (ti->ti_ack == tp->snd_una && |
481 | 429d0a3d | blueswir1 | tcpfrag_list_empty(tp) && |
482 | f0cbd3ec | bellard | ti->ti_len <= sbspace(&so->so_rcv)) { |
483 | f0cbd3ec | bellard | /*
|
484 | f0cbd3ec | bellard | * this is a pure, in-sequence data packet
|
485 | f0cbd3ec | bellard | * with nothing on the reassembly queue and
|
486 | f0cbd3ec | bellard | * we have enough buffer space to take it.
|
487 | f0cbd3ec | bellard | */
|
488 | f0cbd3ec | bellard | tp->rcv_nxt += ti->ti_len; |
489 | f0cbd3ec | bellard | /*
|
490 | f0cbd3ec | bellard | * Add data to socket buffer.
|
491 | f0cbd3ec | bellard | */
|
492 | f0cbd3ec | bellard | if (so->so_emu) {
|
493 | f0cbd3ec | bellard | if (tcp_emu(so,m)) sbappend(so, m);
|
494 | f0cbd3ec | bellard | } else
|
495 | f0cbd3ec | bellard | sbappend(so, m); |
496 | 3b46e624 | ths | |
497 | 5fafdf24 | ths | /*
|
498 | f0cbd3ec | bellard | * If this is a short packet, then ACK now - with Nagel
|
499 | f0cbd3ec | bellard | * congestion avoidance sender won't send more until
|
500 | f0cbd3ec | bellard | * he gets an ACK.
|
501 | 5fafdf24 | ths | *
|
502 | 4f552e3b | bellard | * It is better to not delay acks at all to maximize
|
503 | 4f552e3b | bellard | * TCP throughput. See RFC 2581.
|
504 | 5fafdf24 | ths | */
|
505 | 4f552e3b | bellard | tp->t_flags |= TF_ACKNOW; |
506 | 4f552e3b | bellard | tcp_output(tp); |
507 | f0cbd3ec | bellard | return;
|
508 | f0cbd3ec | bellard | } |
509 | f0cbd3ec | bellard | } /* header prediction */
|
510 | f0cbd3ec | bellard | /*
|
511 | f0cbd3ec | bellard | * Calculate amount of space in receive window,
|
512 | f0cbd3ec | bellard | * and then do TCP input processing.
|
513 | f0cbd3ec | bellard | * Receive window is amount of space in rcv queue,
|
514 | f0cbd3ec | bellard | * but not less than advertised window.
|
515 | f0cbd3ec | bellard | */
|
516 | f0cbd3ec | bellard | { int win;
|
517 | f0cbd3ec | bellard | win = sbspace(&so->so_rcv); |
518 | f0cbd3ec | bellard | if (win < 0) |
519 | f0cbd3ec | bellard | win = 0;
|
520 | f0cbd3ec | bellard | tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));
|
521 | f0cbd3ec | bellard | } |
522 | f0cbd3ec | bellard | |
523 | f0cbd3ec | bellard | switch (tp->t_state) {
|
524 | f0cbd3ec | bellard | |
525 | f0cbd3ec | bellard | /*
|
526 | f0cbd3ec | bellard | * If the state is LISTEN then ignore segment if it contains an RST.
|
527 | f0cbd3ec | bellard | * If the segment contains an ACK then it is bad and send a RST.
|
528 | f0cbd3ec | bellard | * If it does not contain a SYN then it is not interesting; drop it.
|
529 | f0cbd3ec | bellard | * Don't bother responding if the destination was a broadcast.
|
530 | f0cbd3ec | bellard | * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
|
531 | f0cbd3ec | bellard | * tp->iss, and send a segment:
|
532 | f0cbd3ec | bellard | * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
|
533 | f0cbd3ec | bellard | * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
|
534 | f0cbd3ec | bellard | * Fill in remote peer address fields if not previously specified.
|
535 | f0cbd3ec | bellard | * Enter SYN_RECEIVED state, and process any other fields of this
|
536 | f0cbd3ec | bellard | * segment in this state.
|
537 | f0cbd3ec | bellard | */
|
538 | f0cbd3ec | bellard | case TCPS_LISTEN: {
|
539 | f0cbd3ec | bellard | |
540 | f0cbd3ec | bellard | if (tiflags & TH_RST)
|
541 | f0cbd3ec | bellard | goto drop;
|
542 | f0cbd3ec | bellard | if (tiflags & TH_ACK)
|
543 | f0cbd3ec | bellard | goto dropwithreset;
|
544 | f0cbd3ec | bellard | if ((tiflags & TH_SYN) == 0) |
545 | f0cbd3ec | bellard | goto drop;
|
546 | 3b46e624 | ths | |
547 | f0cbd3ec | bellard | /*
|
548 | f0cbd3ec | bellard | * This has way too many gotos...
|
549 | f0cbd3ec | bellard | * But a bit of spaghetti code never hurt anybody :)
|
550 | f0cbd3ec | bellard | */
|
551 | 3b46e624 | ths | |
552 | f0cbd3ec | bellard | /*
|
553 | f0cbd3ec | bellard | * If this is destined for the control address, then flag to
|
554 | f0cbd3ec | bellard | * tcp_ctl once connected, otherwise connect
|
555 | f0cbd3ec | bellard | */
|
556 | 460fec67 | Jan Kiszka | if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
|
557 | 460fec67 | Jan Kiszka | slirp->vnetwork_addr.s_addr) { |
558 | 460fec67 | Jan Kiszka | if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr &&
|
559 | 460fec67 | Jan Kiszka | so->so_faddr.s_addr != slirp->vnameserver_addr.s_addr) { |
560 | f0cbd3ec | bellard | /* May be an add exec */
|
561 | 460fec67 | Jan Kiszka | for (ex_ptr = slirp->exec_list; ex_ptr;
|
562 | 460fec67 | Jan Kiszka | ex_ptr = ex_ptr->ex_next) { |
563 | 5fafdf24 | ths | if(ex_ptr->ex_fport == so->so_fport &&
|
564 | a13a4126 | Jan Kiszka | so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) { |
565 | f0cbd3ec | bellard | so->so_state |= SS_CTL; |
566 | f0cbd3ec | bellard | break;
|
567 | f0cbd3ec | bellard | } |
568 | f0cbd3ec | bellard | } |
569 | 0d62c4cf | Jan Kiszka | if (so->so_state & SS_CTL) {
|
570 | 0d62c4cf | Jan Kiszka | goto cont_input;
|
571 | 0d62c4cf | Jan Kiszka | } |
572 | f0cbd3ec | bellard | } |
573 | f0cbd3ec | bellard | /* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */
|
574 | f0cbd3ec | bellard | } |
575 | 3b46e624 | ths | |
576 | f0cbd3ec | bellard | if (so->so_emu & EMU_NOCONNECT) {
|
577 | f0cbd3ec | bellard | so->so_emu &= ~EMU_NOCONNECT; |
578 | f0cbd3ec | bellard | goto cont_input;
|
579 | f0cbd3ec | bellard | } |
580 | 3b46e624 | ths | |
581 | 02d2c54c | bellard | if((tcp_fconnect(so) == -1) && (errno != EINPROGRESS) && (errno != EWOULDBLOCK)) { |
582 | f0cbd3ec | bellard | u_char code=ICMP_UNREACH_NET; |
583 | f0cbd3ec | bellard | DEBUG_MISC((dfd," tcp fconnect errno = %d-%s\n",
|
584 | f0cbd3ec | bellard | errno,strerror(errno))); |
585 | f0cbd3ec | bellard | if(errno == ECONNREFUSED) {
|
586 | f0cbd3ec | bellard | /* ACK the SYN, send RST to refuse the connection */
|
587 | f0cbd3ec | bellard | tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0, |
588 | 5fafdf24 | ths | TH_RST|TH_ACK); |
589 | f0cbd3ec | bellard | } else {
|
590 | f0cbd3ec | bellard | if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;
|
591 | f0cbd3ec | bellard | HTONL(ti->ti_seq); /* restore tcp header */
|
592 | f0cbd3ec | bellard | HTONL(ti->ti_ack); |
593 | f0cbd3ec | bellard | HTONS(ti->ti_win); |
594 | f0cbd3ec | bellard | HTONS(ti->ti_urp); |
595 | f0cbd3ec | bellard | m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr); |
596 | f0cbd3ec | bellard | m->m_len += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr); |
597 | f0cbd3ec | bellard | *ip=save_ip; |
598 | f0cbd3ec | bellard | icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));
|
599 | f0cbd3ec | bellard | } |
600 | f0cbd3ec | bellard | tp = tcp_close(tp); |
601 | f0cbd3ec | bellard | m_free(m); |
602 | f0cbd3ec | bellard | } else {
|
603 | f0cbd3ec | bellard | /*
|
604 | f0cbd3ec | bellard | * Haven't connected yet, save the current mbuf
|
605 | f0cbd3ec | bellard | * and ti, and return
|
606 | f0cbd3ec | bellard | * XXX Some OS's don't tell us whether the connect()
|
607 | f0cbd3ec | bellard | * succeeded or not. So we must time it out.
|
608 | f0cbd3ec | bellard | */
|
609 | f0cbd3ec | bellard | so->so_m = m; |
610 | f0cbd3ec | bellard | so->so_ti = ti; |
611 | f0cbd3ec | bellard | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; |
612 | f0cbd3ec | bellard | tp->t_state = TCPS_SYN_RECEIVED; |
613 | f0cbd3ec | bellard | } |
614 | f0cbd3ec | bellard | return;
|
615 | f0cbd3ec | bellard | |
616 | 3b46e624 | ths | cont_conn:
|
617 | 5fafdf24 | ths | /* m==NULL
|
618 | f0cbd3ec | bellard | * Check if the connect succeeded
|
619 | f0cbd3ec | bellard | */
|
620 | f0cbd3ec | bellard | if (so->so_state & SS_NOFDREF) {
|
621 | f0cbd3ec | bellard | tp = tcp_close(tp); |
622 | f0cbd3ec | bellard | goto dropwithreset;
|
623 | f0cbd3ec | bellard | } |
624 | 3b46e624 | ths | cont_input:
|
625 | f0cbd3ec | bellard | tcp_template(tp); |
626 | 3b46e624 | ths | |
627 | f0cbd3ec | bellard | if (optp)
|
628 | f0cbd3ec | bellard | tcp_dooptions(tp, (u_char *)optp, optlen, ti); |
629 | 3b46e624 | ths | |
630 | f0cbd3ec | bellard | if (iss)
|
631 | f0cbd3ec | bellard | tp->iss = iss; |
632 | 5fafdf24 | ths | else
|
633 | 460fec67 | Jan Kiszka | tp->iss = slirp->tcp_iss; |
634 | 460fec67 | Jan Kiszka | slirp->tcp_iss += TCP_ISSINCR/2;
|
635 | f0cbd3ec | bellard | tp->irs = ti->ti_seq; |
636 | f0cbd3ec | bellard | tcp_sendseqinit(tp); |
637 | f0cbd3ec | bellard | tcp_rcvseqinit(tp); |
638 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
639 | f0cbd3ec | bellard | tp->t_state = TCPS_SYN_RECEIVED; |
640 | f0cbd3ec | bellard | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; |
641 | f0cbd3ec | bellard | goto trimthenstep6;
|
642 | f0cbd3ec | bellard | } /* case TCPS_LISTEN */
|
643 | 5fafdf24 | ths | |
644 | f0cbd3ec | bellard | /*
|
645 | f0cbd3ec | bellard | * If the state is SYN_SENT:
|
646 | f0cbd3ec | bellard | * if seg contains an ACK, but not for our SYN, drop the input.
|
647 | f0cbd3ec | bellard | * if seg contains a RST, then drop the connection.
|
648 | f0cbd3ec | bellard | * if seg does not contain SYN, then drop it.
|
649 | f0cbd3ec | bellard | * Otherwise this is an acceptable SYN segment
|
650 | f0cbd3ec | bellard | * initialize tp->rcv_nxt and tp->irs
|
651 | f0cbd3ec | bellard | * if seg contains ack then advance tp->snd_una
|
652 | f0cbd3ec | bellard | * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
|
653 | f0cbd3ec | bellard | * arrange for segment to be acked (eventually)
|
654 | f0cbd3ec | bellard | * continue processing rest of data/controls, beginning with URG
|
655 | f0cbd3ec | bellard | */
|
656 | f0cbd3ec | bellard | case TCPS_SYN_SENT:
|
657 | f0cbd3ec | bellard | if ((tiflags & TH_ACK) &&
|
658 | f0cbd3ec | bellard | (SEQ_LEQ(ti->ti_ack, tp->iss) || |
659 | f0cbd3ec | bellard | SEQ_GT(ti->ti_ack, tp->snd_max))) |
660 | f0cbd3ec | bellard | goto dropwithreset;
|
661 | f0cbd3ec | bellard | |
662 | f0cbd3ec | bellard | if (tiflags & TH_RST) {
|
663 | f0cbd3ec | bellard | if (tiflags & TH_ACK)
|
664 | f0cbd3ec | bellard | tp = tcp_drop(tp,0); /* XXX Check t_softerror! */ |
665 | f0cbd3ec | bellard | goto drop;
|
666 | f0cbd3ec | bellard | } |
667 | f0cbd3ec | bellard | |
668 | f0cbd3ec | bellard | if ((tiflags & TH_SYN) == 0) |
669 | f0cbd3ec | bellard | goto drop;
|
670 | f0cbd3ec | bellard | if (tiflags & TH_ACK) {
|
671 | f0cbd3ec | bellard | tp->snd_una = ti->ti_ack; |
672 | f0cbd3ec | bellard | if (SEQ_LT(tp->snd_nxt, tp->snd_una))
|
673 | f0cbd3ec | bellard | tp->snd_nxt = tp->snd_una; |
674 | f0cbd3ec | bellard | } |
675 | f0cbd3ec | bellard | |
676 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = 0;
|
677 | f0cbd3ec | bellard | tp->irs = ti->ti_seq; |
678 | f0cbd3ec | bellard | tcp_rcvseqinit(tp); |
679 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
680 | f0cbd3ec | bellard | if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {
|
681 | f0cbd3ec | bellard | soisfconnected(so); |
682 | f0cbd3ec | bellard | tp->t_state = TCPS_ESTABLISHED; |
683 | 3b46e624 | ths | |
684 | f0cbd3ec | bellard | (void) tcp_reass(tp, (struct tcpiphdr *)0, |
685 | f0cbd3ec | bellard | (struct mbuf *)0); |
686 | f0cbd3ec | bellard | /*
|
687 | f0cbd3ec | bellard | * if we didn't have to retransmit the SYN,
|
688 | f0cbd3ec | bellard | * use its rtt as our initial srtt & rtt var.
|
689 | f0cbd3ec | bellard | */
|
690 | f0cbd3ec | bellard | if (tp->t_rtt)
|
691 | f0cbd3ec | bellard | tcp_xmit_timer(tp, tp->t_rtt); |
692 | f0cbd3ec | bellard | } else
|
693 | f0cbd3ec | bellard | tp->t_state = TCPS_SYN_RECEIVED; |
694 | f0cbd3ec | bellard | |
695 | f0cbd3ec | bellard | trimthenstep6:
|
696 | f0cbd3ec | bellard | /*
|
697 | f0cbd3ec | bellard | * Advance ti->ti_seq to correspond to first data byte.
|
698 | f0cbd3ec | bellard | * If data, trim to stay within window,
|
699 | f0cbd3ec | bellard | * dropping FIN if necessary.
|
700 | f0cbd3ec | bellard | */
|
701 | f0cbd3ec | bellard | ti->ti_seq++; |
702 | f0cbd3ec | bellard | if (ti->ti_len > tp->rcv_wnd) {
|
703 | f0cbd3ec | bellard | todrop = ti->ti_len - tp->rcv_wnd; |
704 | f0cbd3ec | bellard | m_adj(m, -todrop); |
705 | f0cbd3ec | bellard | ti->ti_len = tp->rcv_wnd; |
706 | f0cbd3ec | bellard | tiflags &= ~TH_FIN; |
707 | f0cbd3ec | bellard | } |
708 | f0cbd3ec | bellard | tp->snd_wl1 = ti->ti_seq - 1;
|
709 | f0cbd3ec | bellard | tp->rcv_up = ti->ti_seq; |
710 | f0cbd3ec | bellard | goto step6;
|
711 | f0cbd3ec | bellard | } /* switch tp->t_state */
|
712 | f0cbd3ec | bellard | /*
|
713 | f0cbd3ec | bellard | * States other than LISTEN or SYN_SENT.
|
714 | 0d62c4cf | Jan Kiszka | * Check that at least some bytes of segment are within
|
715 | f0cbd3ec | bellard | * receive window. If segment begins before rcv_nxt,
|
716 | f0cbd3ec | bellard | * drop leading data (and SYN); if nothing left, just ack.
|
717 | f0cbd3ec | bellard | */
|
718 | f0cbd3ec | bellard | todrop = tp->rcv_nxt - ti->ti_seq; |
719 | f0cbd3ec | bellard | if (todrop > 0) { |
720 | f0cbd3ec | bellard | if (tiflags & TH_SYN) {
|
721 | f0cbd3ec | bellard | tiflags &= ~TH_SYN; |
722 | f0cbd3ec | bellard | ti->ti_seq++; |
723 | 5fafdf24 | ths | if (ti->ti_urp > 1) |
724 | f0cbd3ec | bellard | ti->ti_urp--; |
725 | f0cbd3ec | bellard | else
|
726 | f0cbd3ec | bellard | tiflags &= ~TH_URG; |
727 | f0cbd3ec | bellard | todrop--; |
728 | f0cbd3ec | bellard | } |
729 | f0cbd3ec | bellard | /*
|
730 | f0cbd3ec | bellard | * Following if statement from Stevens, vol. 2, p. 960.
|
731 | f0cbd3ec | bellard | */
|
732 | f0cbd3ec | bellard | if (todrop > ti->ti_len
|
733 | f0cbd3ec | bellard | || (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {
|
734 | f0cbd3ec | bellard | /*
|
735 | f0cbd3ec | bellard | * Any valid FIN must be to the left of the window.
|
736 | f0cbd3ec | bellard | * At this point the FIN must be a duplicate or out
|
737 | f0cbd3ec | bellard | * of sequence; drop it.
|
738 | f0cbd3ec | bellard | */
|
739 | f0cbd3ec | bellard | tiflags &= ~TH_FIN; |
740 | 3b46e624 | ths | |
741 | f0cbd3ec | bellard | /*
|
742 | f0cbd3ec | bellard | * Send an ACK to resynchronize and drop any data.
|
743 | f0cbd3ec | bellard | * But keep on processing for RST or ACK.
|
744 | f0cbd3ec | bellard | */
|
745 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
746 | f0cbd3ec | bellard | todrop = ti->ti_len; |
747 | f0cbd3ec | bellard | } |
748 | f0cbd3ec | bellard | m_adj(m, todrop); |
749 | f0cbd3ec | bellard | ti->ti_seq += todrop; |
750 | f0cbd3ec | bellard | ti->ti_len -= todrop; |
751 | f0cbd3ec | bellard | if (ti->ti_urp > todrop)
|
752 | f0cbd3ec | bellard | ti->ti_urp -= todrop; |
753 | f0cbd3ec | bellard | else {
|
754 | f0cbd3ec | bellard | tiflags &= ~TH_URG; |
755 | f0cbd3ec | bellard | ti->ti_urp = 0;
|
756 | f0cbd3ec | bellard | } |
757 | f0cbd3ec | bellard | } |
758 | f0cbd3ec | bellard | /*
|
759 | f0cbd3ec | bellard | * If new data are received on a connection after the
|
760 | f0cbd3ec | bellard | * user processes are gone, then RST the other end.
|
761 | f0cbd3ec | bellard | */
|
762 | f0cbd3ec | bellard | if ((so->so_state & SS_NOFDREF) &&
|
763 | f0cbd3ec | bellard | tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) { |
764 | f0cbd3ec | bellard | tp = tcp_close(tp); |
765 | f0cbd3ec | bellard | goto dropwithreset;
|
766 | f0cbd3ec | bellard | } |
767 | f0cbd3ec | bellard | |
768 | f0cbd3ec | bellard | /*
|
769 | f0cbd3ec | bellard | * If segment ends after window, drop trailing data
|
770 | f0cbd3ec | bellard | * (and PUSH and FIN); if nothing left, just ACK.
|
771 | f0cbd3ec | bellard | */
|
772 | f0cbd3ec | bellard | todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd); |
773 | f0cbd3ec | bellard | if (todrop > 0) { |
774 | f0cbd3ec | bellard | if (todrop >= ti->ti_len) {
|
775 | f0cbd3ec | bellard | /*
|
776 | f0cbd3ec | bellard | * If a new connection request is received
|
777 | f0cbd3ec | bellard | * while in TIME_WAIT, drop the old connection
|
778 | f0cbd3ec | bellard | * and start over if the sequence numbers
|
779 | f0cbd3ec | bellard | * are above the previous ones.
|
780 | f0cbd3ec | bellard | */
|
781 | f0cbd3ec | bellard | if (tiflags & TH_SYN &&
|
782 | f0cbd3ec | bellard | tp->t_state == TCPS_TIME_WAIT && |
783 | f0cbd3ec | bellard | SEQ_GT(ti->ti_seq, tp->rcv_nxt)) { |
784 | f0cbd3ec | bellard | iss = tp->rcv_nxt + TCP_ISSINCR; |
785 | f0cbd3ec | bellard | tp = tcp_close(tp); |
786 | f0cbd3ec | bellard | goto findso;
|
787 | f0cbd3ec | bellard | } |
788 | f0cbd3ec | bellard | /*
|
789 | f0cbd3ec | bellard | * If window is closed can only take segments at
|
790 | f0cbd3ec | bellard | * window edge, and have to drop data and PUSH from
|
791 | f0cbd3ec | bellard | * incoming segments. Continue processing, but
|
792 | f0cbd3ec | bellard | * remember to ack. Otherwise, drop segment
|
793 | f0cbd3ec | bellard | * and ack.
|
794 | f0cbd3ec | bellard | */
|
795 | f0cbd3ec | bellard | if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) { |
796 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
797 | 0fe6a7f2 | Jan Kiszka | } else {
|
798 | f0cbd3ec | bellard | goto dropafterack;
|
799 | 0fe6a7f2 | Jan Kiszka | } |
800 | 0fe6a7f2 | Jan Kiszka | } |
801 | f0cbd3ec | bellard | m_adj(m, -todrop); |
802 | f0cbd3ec | bellard | ti->ti_len -= todrop; |
803 | f0cbd3ec | bellard | tiflags &= ~(TH_PUSH|TH_FIN); |
804 | f0cbd3ec | bellard | } |
805 | f0cbd3ec | bellard | |
806 | f0cbd3ec | bellard | /*
|
807 | f0cbd3ec | bellard | * If the RST bit is set examine the state:
|
808 | f0cbd3ec | bellard | * SYN_RECEIVED STATE:
|
809 | f0cbd3ec | bellard | * If passive open, return to LISTEN state.
|
810 | f0cbd3ec | bellard | * If active open, inform user that connection was refused.
|
811 | f0cbd3ec | bellard | * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
|
812 | f0cbd3ec | bellard | * Inform user that connection was reset, and close tcb.
|
813 | f0cbd3ec | bellard | * CLOSING, LAST_ACK, TIME_WAIT STATES
|
814 | f0cbd3ec | bellard | * Close the tcb.
|
815 | f0cbd3ec | bellard | */
|
816 | f0cbd3ec | bellard | if (tiflags&TH_RST) switch (tp->t_state) { |
817 | f0cbd3ec | bellard | |
818 | f0cbd3ec | bellard | case TCPS_SYN_RECEIVED:
|
819 | f0cbd3ec | bellard | case TCPS_ESTABLISHED:
|
820 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_1:
|
821 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_2:
|
822 | f0cbd3ec | bellard | case TCPS_CLOSE_WAIT:
|
823 | f0cbd3ec | bellard | tp->t_state = TCPS_CLOSED; |
824 | f0cbd3ec | bellard | tp = tcp_close(tp); |
825 | f0cbd3ec | bellard | goto drop;
|
826 | f0cbd3ec | bellard | |
827 | f0cbd3ec | bellard | case TCPS_CLOSING:
|
828 | f0cbd3ec | bellard | case TCPS_LAST_ACK:
|
829 | f0cbd3ec | bellard | case TCPS_TIME_WAIT:
|
830 | f0cbd3ec | bellard | tp = tcp_close(tp); |
831 | f0cbd3ec | bellard | goto drop;
|
832 | f0cbd3ec | bellard | } |
833 | f0cbd3ec | bellard | |
834 | f0cbd3ec | bellard | /*
|
835 | f0cbd3ec | bellard | * If a SYN is in the window, then this is an
|
836 | f0cbd3ec | bellard | * error and we send an RST and drop the connection.
|
837 | f0cbd3ec | bellard | */
|
838 | f0cbd3ec | bellard | if (tiflags & TH_SYN) {
|
839 | f0cbd3ec | bellard | tp = tcp_drop(tp,0);
|
840 | f0cbd3ec | bellard | goto dropwithreset;
|
841 | f0cbd3ec | bellard | } |
842 | f0cbd3ec | bellard | |
843 | f0cbd3ec | bellard | /*
|
844 | f0cbd3ec | bellard | * If the ACK bit is off we drop the segment and return.
|
845 | f0cbd3ec | bellard | */
|
846 | f0cbd3ec | bellard | if ((tiflags & TH_ACK) == 0) goto drop; |
847 | f0cbd3ec | bellard | |
848 | f0cbd3ec | bellard | /*
|
849 | f0cbd3ec | bellard | * Ack processing.
|
850 | f0cbd3ec | bellard | */
|
851 | f0cbd3ec | bellard | switch (tp->t_state) {
|
852 | f0cbd3ec | bellard | /*
|
853 | f0cbd3ec | bellard | * In SYN_RECEIVED state if the ack ACKs our SYN then enter
|
854 | f0cbd3ec | bellard | * ESTABLISHED state and continue processing, otherwise
|
855 | f0cbd3ec | bellard | * send an RST. una<=ack<=max
|
856 | f0cbd3ec | bellard | */
|
857 | f0cbd3ec | bellard | case TCPS_SYN_RECEIVED:
|
858 | f0cbd3ec | bellard | |
859 | f0cbd3ec | bellard | if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
|
860 | f0cbd3ec | bellard | SEQ_GT(ti->ti_ack, tp->snd_max)) |
861 | f0cbd3ec | bellard | goto dropwithreset;
|
862 | f0cbd3ec | bellard | tp->t_state = TCPS_ESTABLISHED; |
863 | 5fafdf24 | ths | /*
|
864 | 5fafdf24 | ths | * The sent SYN is ack'ed with our sequence number +1
|
865 | 5fafdf24 | ths | * The first data byte already in the buffer will get
|
866 | f0cbd3ec | bellard | * lost if no correction is made. This is only needed for
|
867 | f0cbd3ec | bellard | * SS_CTL since the buffer is empty otherwise.
|
868 | 3b46e624 | ths | * tp->snd_una++; or:
|
869 | f0cbd3ec | bellard | */
|
870 | f0cbd3ec | bellard | tp->snd_una=ti->ti_ack; |
871 | f0cbd3ec | bellard | if (so->so_state & SS_CTL) {
|
872 | f0cbd3ec | bellard | /* So tcp_ctl reports the right state */
|
873 | f0cbd3ec | bellard | ret = tcp_ctl(so); |
874 | f0cbd3ec | bellard | if (ret == 1) { |
875 | f0cbd3ec | bellard | soisfconnected(so); |
876 | f0cbd3ec | bellard | so->so_state &= ~SS_CTL; /* success XXX */
|
877 | f0cbd3ec | bellard | } else if (ret == 2) { |
878 | f932b6ce | Jan Kiszka | so->so_state &= SS_PERSISTENT_MASK; |
879 | f932b6ce | Jan Kiszka | so->so_state |= SS_NOFDREF; /* CTL_CMD */
|
880 | f0cbd3ec | bellard | } else {
|
881 | f0cbd3ec | bellard | needoutput = 1;
|
882 | f0cbd3ec | bellard | tp->t_state = TCPS_FIN_WAIT_1; |
883 | f0cbd3ec | bellard | } |
884 | f0cbd3ec | bellard | } else {
|
885 | f0cbd3ec | bellard | soisfconnected(so); |
886 | f0cbd3ec | bellard | } |
887 | 3b46e624 | ths | |
888 | f0cbd3ec | bellard | (void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0); |
889 | f0cbd3ec | bellard | tp->snd_wl1 = ti->ti_seq - 1;
|
890 | f0cbd3ec | bellard | /* Avoid ack processing; snd_una==ti_ack => dup ack */
|
891 | f0cbd3ec | bellard | goto synrx_to_est;
|
892 | f0cbd3ec | bellard | /* fall into ... */
|
893 | f0cbd3ec | bellard | |
894 | f0cbd3ec | bellard | /*
|
895 | f0cbd3ec | bellard | * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
|
896 | f0cbd3ec | bellard | * ACKs. If the ack is in the range
|
897 | f0cbd3ec | bellard | * tp->snd_una < ti->ti_ack <= tp->snd_max
|
898 | f0cbd3ec | bellard | * then advance tp->snd_una to ti->ti_ack and drop
|
899 | f0cbd3ec | bellard | * data from the retransmission queue. If this ACK reflects
|
900 | f0cbd3ec | bellard | * more up to date window information we update our window information.
|
901 | f0cbd3ec | bellard | */
|
902 | f0cbd3ec | bellard | case TCPS_ESTABLISHED:
|
903 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_1:
|
904 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_2:
|
905 | f0cbd3ec | bellard | case TCPS_CLOSE_WAIT:
|
906 | f0cbd3ec | bellard | case TCPS_CLOSING:
|
907 | f0cbd3ec | bellard | case TCPS_LAST_ACK:
|
908 | f0cbd3ec | bellard | case TCPS_TIME_WAIT:
|
909 | f0cbd3ec | bellard | |
910 | f0cbd3ec | bellard | if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {
|
911 | f0cbd3ec | bellard | if (ti->ti_len == 0 && tiwin == tp->snd_wnd) { |
912 | f0cbd3ec | bellard | DEBUG_MISC((dfd," dup ack m = %lx so = %lx \n",
|
913 | f0cbd3ec | bellard | (long )m, (long )so)); |
914 | f0cbd3ec | bellard | /*
|
915 | f0cbd3ec | bellard | * If we have outstanding data (other than
|
916 | f0cbd3ec | bellard | * a window probe), this is a completely
|
917 | f0cbd3ec | bellard | * duplicate ack (ie, window info didn't
|
918 | f0cbd3ec | bellard | * change), the ack is the biggest we've
|
919 | f0cbd3ec | bellard | * seen and we've seen exactly our rexmt
|
920 | f0cbd3ec | bellard | * threshold of them, assume a packet
|
921 | f0cbd3ec | bellard | * has been dropped and retransmit it.
|
922 | f0cbd3ec | bellard | * Kludge snd_nxt & the congestion
|
923 | f0cbd3ec | bellard | * window so we send only this one
|
924 | f0cbd3ec | bellard | * packet.
|
925 | f0cbd3ec | bellard | *
|
926 | f0cbd3ec | bellard | * We know we're losing at the current
|
927 | f0cbd3ec | bellard | * window size so do congestion avoidance
|
928 | f0cbd3ec | bellard | * (set ssthresh to half the current window
|
929 | f0cbd3ec | bellard | * and pull our congestion window back to
|
930 | f0cbd3ec | bellard | * the new ssthresh).
|
931 | f0cbd3ec | bellard | *
|
932 | f0cbd3ec | bellard | * Dup acks mean that packets have left the
|
933 | 5fafdf24 | ths | * network (they're now cached at the receiver)
|
934 | f0cbd3ec | bellard | * so bump cwnd by the amount in the receiver
|
935 | f0cbd3ec | bellard | * to keep a constant cwnd packets in the
|
936 | f0cbd3ec | bellard | * network.
|
937 | f0cbd3ec | bellard | */
|
938 | f0cbd3ec | bellard | if (tp->t_timer[TCPT_REXMT] == 0 || |
939 | f0cbd3ec | bellard | ti->ti_ack != tp->snd_una) |
940 | f0cbd3ec | bellard | tp->t_dupacks = 0;
|
941 | 9634d903 | blueswir1 | else if (++tp->t_dupacks == TCPREXMTTHRESH) { |
942 | f0cbd3ec | bellard | tcp_seq onxt = tp->snd_nxt; |
943 | f0cbd3ec | bellard | u_int win = |
944 | f0cbd3ec | bellard | min(tp->snd_wnd, tp->snd_cwnd) / 2 /
|
945 | f0cbd3ec | bellard | tp->t_maxseg; |
946 | f0cbd3ec | bellard | |
947 | f0cbd3ec | bellard | if (win < 2) |
948 | f0cbd3ec | bellard | win = 2;
|
949 | f0cbd3ec | bellard | tp->snd_ssthresh = win * tp->t_maxseg; |
950 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = 0;
|
951 | f0cbd3ec | bellard | tp->t_rtt = 0;
|
952 | f0cbd3ec | bellard | tp->snd_nxt = ti->ti_ack; |
953 | f0cbd3ec | bellard | tp->snd_cwnd = tp->t_maxseg; |
954 | f0cbd3ec | bellard | (void) tcp_output(tp);
|
955 | f0cbd3ec | bellard | tp->snd_cwnd = tp->snd_ssthresh + |
956 | f0cbd3ec | bellard | tp->t_maxseg * tp->t_dupacks; |
957 | f0cbd3ec | bellard | if (SEQ_GT(onxt, tp->snd_nxt))
|
958 | f0cbd3ec | bellard | tp->snd_nxt = onxt; |
959 | f0cbd3ec | bellard | goto drop;
|
960 | 9634d903 | blueswir1 | } else if (tp->t_dupacks > TCPREXMTTHRESH) { |
961 | f0cbd3ec | bellard | tp->snd_cwnd += tp->t_maxseg; |
962 | f0cbd3ec | bellard | (void) tcp_output(tp);
|
963 | f0cbd3ec | bellard | goto drop;
|
964 | f0cbd3ec | bellard | } |
965 | f0cbd3ec | bellard | } else
|
966 | f0cbd3ec | bellard | tp->t_dupacks = 0;
|
967 | f0cbd3ec | bellard | break;
|
968 | f0cbd3ec | bellard | } |
969 | f0cbd3ec | bellard | synrx_to_est:
|
970 | f0cbd3ec | bellard | /*
|
971 | f0cbd3ec | bellard | * If the congestion window was inflated to account
|
972 | f0cbd3ec | bellard | * for the other side's cached packets, retract it.
|
973 | f0cbd3ec | bellard | */
|
974 | 9634d903 | blueswir1 | if (tp->t_dupacks > TCPREXMTTHRESH &&
|
975 | f0cbd3ec | bellard | tp->snd_cwnd > tp->snd_ssthresh) |
976 | f0cbd3ec | bellard | tp->snd_cwnd = tp->snd_ssthresh; |
977 | f0cbd3ec | bellard | tp->t_dupacks = 0;
|
978 | f0cbd3ec | bellard | if (SEQ_GT(ti->ti_ack, tp->snd_max)) {
|
979 | f0cbd3ec | bellard | goto dropafterack;
|
980 | f0cbd3ec | bellard | } |
981 | f0cbd3ec | bellard | acked = ti->ti_ack - tp->snd_una; |
982 | f0cbd3ec | bellard | |
983 | f0cbd3ec | bellard | /*
|
984 | 0d62c4cf | Jan Kiszka | * If transmit timer is running and timed sequence
|
985 | f0cbd3ec | bellard | * number was acked, update smoothed round trip time.
|
986 | f0cbd3ec | bellard | * Since we now have an rtt measurement, cancel the
|
987 | f0cbd3ec | bellard | * timer backoff (cf., Phil Karn's retransmit alg.).
|
988 | f0cbd3ec | bellard | * Recompute the initial retransmit timer.
|
989 | f0cbd3ec | bellard | */
|
990 | 0d62c4cf | Jan Kiszka | if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))
|
991 | f0cbd3ec | bellard | tcp_xmit_timer(tp,tp->t_rtt); |
992 | f0cbd3ec | bellard | |
993 | f0cbd3ec | bellard | /*
|
994 | f0cbd3ec | bellard | * If all outstanding data is acked, stop retransmit
|
995 | f0cbd3ec | bellard | * timer and remember to restart (more output or persist).
|
996 | f0cbd3ec | bellard | * If there is more data to be acked, restart retransmit
|
997 | f0cbd3ec | bellard | * timer, using current (possibly backed-off) value.
|
998 | f0cbd3ec | bellard | */
|
999 | f0cbd3ec | bellard | if (ti->ti_ack == tp->snd_max) {
|
1000 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = 0;
|
1001 | f0cbd3ec | bellard | needoutput = 1;
|
1002 | f0cbd3ec | bellard | } else if (tp->t_timer[TCPT_PERSIST] == 0) |
1003 | f0cbd3ec | bellard | tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; |
1004 | f0cbd3ec | bellard | /*
|
1005 | f0cbd3ec | bellard | * When new data is acked, open the congestion window.
|
1006 | f0cbd3ec | bellard | * If the window gives us less than ssthresh packets
|
1007 | f0cbd3ec | bellard | * in flight, open exponentially (maxseg per packet).
|
1008 | f0cbd3ec | bellard | * Otherwise open linearly: maxseg per window
|
1009 | f0cbd3ec | bellard | * (maxseg^2 / cwnd per packet).
|
1010 | f0cbd3ec | bellard | */
|
1011 | f0cbd3ec | bellard | { |
1012 | f0cbd3ec | bellard | register u_int cw = tp->snd_cwnd;
|
1013 | f0cbd3ec | bellard | register u_int incr = tp->t_maxseg;
|
1014 | f0cbd3ec | bellard | |
1015 | f0cbd3ec | bellard | if (cw > tp->snd_ssthresh)
|
1016 | f0cbd3ec | bellard | incr = incr * incr / cw; |
1017 | f0cbd3ec | bellard | tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale); |
1018 | f0cbd3ec | bellard | } |
1019 | f0cbd3ec | bellard | if (acked > so->so_snd.sb_cc) {
|
1020 | f0cbd3ec | bellard | tp->snd_wnd -= so->so_snd.sb_cc; |
1021 | f0cbd3ec | bellard | sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);
|
1022 | f0cbd3ec | bellard | ourfinisacked = 1;
|
1023 | f0cbd3ec | bellard | } else {
|
1024 | f0cbd3ec | bellard | sbdrop(&so->so_snd, acked); |
1025 | f0cbd3ec | bellard | tp->snd_wnd -= acked; |
1026 | f0cbd3ec | bellard | ourfinisacked = 0;
|
1027 | f0cbd3ec | bellard | } |
1028 | f0cbd3ec | bellard | tp->snd_una = ti->ti_ack; |
1029 | f0cbd3ec | bellard | if (SEQ_LT(tp->snd_nxt, tp->snd_una))
|
1030 | f0cbd3ec | bellard | tp->snd_nxt = tp->snd_una; |
1031 | f0cbd3ec | bellard | |
1032 | f0cbd3ec | bellard | switch (tp->t_state) {
|
1033 | f0cbd3ec | bellard | |
1034 | f0cbd3ec | bellard | /*
|
1035 | f0cbd3ec | bellard | * In FIN_WAIT_1 STATE in addition to the processing
|
1036 | f0cbd3ec | bellard | * for the ESTABLISHED state if our FIN is now acknowledged
|
1037 | f0cbd3ec | bellard | * then enter FIN_WAIT_2.
|
1038 | f0cbd3ec | bellard | */
|
1039 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_1:
|
1040 | f0cbd3ec | bellard | if (ourfinisacked) {
|
1041 | f0cbd3ec | bellard | /*
|
1042 | f0cbd3ec | bellard | * If we can't receive any more
|
1043 | f0cbd3ec | bellard | * data, then closing user can proceed.
|
1044 | f0cbd3ec | bellard | * Starting the timer is contrary to the
|
1045 | f0cbd3ec | bellard | * specification, but if we don't get a FIN
|
1046 | f0cbd3ec | bellard | * we'll hang forever.
|
1047 | f0cbd3ec | bellard | */
|
1048 | f0cbd3ec | bellard | if (so->so_state & SS_FCANTRCVMORE) {
|
1049 | 9634d903 | blueswir1 | tp->t_timer[TCPT_2MSL] = TCP_MAXIDLE; |
1050 | f0cbd3ec | bellard | } |
1051 | f0cbd3ec | bellard | tp->t_state = TCPS_FIN_WAIT_2; |
1052 | f0cbd3ec | bellard | } |
1053 | f0cbd3ec | bellard | break;
|
1054 | f0cbd3ec | bellard | |
1055 | f0cbd3ec | bellard | /*
|
1056 | f0cbd3ec | bellard | * In CLOSING STATE in addition to the processing for
|
1057 | f0cbd3ec | bellard | * the ESTABLISHED state if the ACK acknowledges our FIN
|
1058 | f0cbd3ec | bellard | * then enter the TIME-WAIT state, otherwise ignore
|
1059 | f0cbd3ec | bellard | * the segment.
|
1060 | f0cbd3ec | bellard | */
|
1061 | f0cbd3ec | bellard | case TCPS_CLOSING:
|
1062 | f0cbd3ec | bellard | if (ourfinisacked) {
|
1063 | f0cbd3ec | bellard | tp->t_state = TCPS_TIME_WAIT; |
1064 | f0cbd3ec | bellard | tcp_canceltimers(tp); |
1065 | f0cbd3ec | bellard | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
|
1066 | f0cbd3ec | bellard | } |
1067 | f0cbd3ec | bellard | break;
|
1068 | f0cbd3ec | bellard | |
1069 | f0cbd3ec | bellard | /*
|
1070 | f0cbd3ec | bellard | * In LAST_ACK, we may still be waiting for data to drain
|
1071 | f0cbd3ec | bellard | * and/or to be acked, as well as for the ack of our FIN.
|
1072 | f0cbd3ec | bellard | * If our FIN is now acknowledged, delete the TCB,
|
1073 | f0cbd3ec | bellard | * enter the closed state and return.
|
1074 | f0cbd3ec | bellard | */
|
1075 | f0cbd3ec | bellard | case TCPS_LAST_ACK:
|
1076 | f0cbd3ec | bellard | if (ourfinisacked) {
|
1077 | f0cbd3ec | bellard | tp = tcp_close(tp); |
1078 | f0cbd3ec | bellard | goto drop;
|
1079 | f0cbd3ec | bellard | } |
1080 | f0cbd3ec | bellard | break;
|
1081 | f0cbd3ec | bellard | |
1082 | f0cbd3ec | bellard | /*
|
1083 | f0cbd3ec | bellard | * In TIME_WAIT state the only thing that should arrive
|
1084 | f0cbd3ec | bellard | * is a retransmission of the remote FIN. Acknowledge
|
1085 | f0cbd3ec | bellard | * it and restart the finack timer.
|
1086 | f0cbd3ec | bellard | */
|
1087 | f0cbd3ec | bellard | case TCPS_TIME_WAIT:
|
1088 | f0cbd3ec | bellard | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
|
1089 | f0cbd3ec | bellard | goto dropafterack;
|
1090 | f0cbd3ec | bellard | } |
1091 | f0cbd3ec | bellard | } /* switch(tp->t_state) */
|
1092 | f0cbd3ec | bellard | |
1093 | f0cbd3ec | bellard | step6:
|
1094 | f0cbd3ec | bellard | /*
|
1095 | f0cbd3ec | bellard | * Update window information.
|
1096 | f0cbd3ec | bellard | * Don't look at window if no ACK: TAC's send garbage on first SYN.
|
1097 | f0cbd3ec | bellard | */
|
1098 | f0cbd3ec | bellard | if ((tiflags & TH_ACK) &&
|
1099 | 5fafdf24 | ths | (SEQ_LT(tp->snd_wl1, ti->ti_seq) || |
1100 | f0cbd3ec | bellard | (tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) || |
1101 | f0cbd3ec | bellard | (tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) { |
1102 | f0cbd3ec | bellard | tp->snd_wnd = tiwin; |
1103 | f0cbd3ec | bellard | tp->snd_wl1 = ti->ti_seq; |
1104 | f0cbd3ec | bellard | tp->snd_wl2 = ti->ti_ack; |
1105 | f0cbd3ec | bellard | if (tp->snd_wnd > tp->max_sndwnd)
|
1106 | f0cbd3ec | bellard | tp->max_sndwnd = tp->snd_wnd; |
1107 | f0cbd3ec | bellard | needoutput = 1;
|
1108 | f0cbd3ec | bellard | } |
1109 | f0cbd3ec | bellard | |
1110 | f0cbd3ec | bellard | /*
|
1111 | f0cbd3ec | bellard | * Process segments with URG.
|
1112 | f0cbd3ec | bellard | */
|
1113 | f0cbd3ec | bellard | if ((tiflags & TH_URG) && ti->ti_urp &&
|
1114 | f0cbd3ec | bellard | TCPS_HAVERCVDFIN(tp->t_state) == 0) {
|
1115 | f0cbd3ec | bellard | /*
|
1116 | f0cbd3ec | bellard | * This is a kludge, but if we receive and accept
|
1117 | f0cbd3ec | bellard | * random urgent pointers, we'll crash in
|
1118 | f0cbd3ec | bellard | * soreceive. It's hard to imagine someone
|
1119 | f0cbd3ec | bellard | * actually wanting to send this much urgent data.
|
1120 | f0cbd3ec | bellard | */
|
1121 | f0cbd3ec | bellard | if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {
|
1122 | f0cbd3ec | bellard | ti->ti_urp = 0;
|
1123 | f0cbd3ec | bellard | tiflags &= ~TH_URG; |
1124 | f0cbd3ec | bellard | goto dodata;
|
1125 | f0cbd3ec | bellard | } |
1126 | f0cbd3ec | bellard | /*
|
1127 | f0cbd3ec | bellard | * If this segment advances the known urgent pointer,
|
1128 | f0cbd3ec | bellard | * then mark the data stream. This should not happen
|
1129 | f0cbd3ec | bellard | * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
|
1130 | 5fafdf24 | ths | * a FIN has been received from the remote side.
|
1131 | f0cbd3ec | bellard | * In these states we ignore the URG.
|
1132 | f0cbd3ec | bellard | *
|
1133 | f0cbd3ec | bellard | * According to RFC961 (Assigned Protocols),
|
1134 | f0cbd3ec | bellard | * the urgent pointer points to the last octet
|
1135 | f0cbd3ec | bellard | * of urgent data. We continue, however,
|
1136 | f0cbd3ec | bellard | * to consider it to indicate the first octet
|
1137 | 5fafdf24 | ths | * of data past the urgent section as the original
|
1138 | f0cbd3ec | bellard | * spec states (in one of two places).
|
1139 | f0cbd3ec | bellard | */
|
1140 | f0cbd3ec | bellard | if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
|
1141 | f0cbd3ec | bellard | tp->rcv_up = ti->ti_seq + ti->ti_urp; |
1142 | f0cbd3ec | bellard | so->so_urgc = so->so_rcv.sb_cc + |
1143 | f0cbd3ec | bellard | (tp->rcv_up - tp->rcv_nxt); /* -1; */
|
1144 | f0cbd3ec | bellard | tp->rcv_up = ti->ti_seq + ti->ti_urp; |
1145 | 3b46e624 | ths | |
1146 | f0cbd3ec | bellard | } |
1147 | f0cbd3ec | bellard | } else
|
1148 | f0cbd3ec | bellard | /*
|
1149 | f0cbd3ec | bellard | * If no out of band data is expected,
|
1150 | f0cbd3ec | bellard | * pull receive urgent pointer along
|
1151 | f0cbd3ec | bellard | * with the receive window.
|
1152 | f0cbd3ec | bellard | */
|
1153 | f0cbd3ec | bellard | if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
|
1154 | f0cbd3ec | bellard | tp->rcv_up = tp->rcv_nxt; |
1155 | f0cbd3ec | bellard | dodata:
|
1156 | f0cbd3ec | bellard | |
1157 | f0cbd3ec | bellard | /*
|
1158 | f0cbd3ec | bellard | * Process the segment text, merging it into the TCP sequencing queue,
|
1159 | f0cbd3ec | bellard | * and arranging for acknowledgment of receipt if necessary.
|
1160 | f0cbd3ec | bellard | * This process logically involves adjusting tp->rcv_wnd as data
|
1161 | f0cbd3ec | bellard | * is presented to the user (this happens in tcp_usrreq.c,
|
1162 | f0cbd3ec | bellard | * case PRU_RCVD). If a FIN has already been received on this
|
1163 | f0cbd3ec | bellard | * connection then we just ignore the text.
|
1164 | f0cbd3ec | bellard | */
|
1165 | f0cbd3ec | bellard | if ((ti->ti_len || (tiflags&TH_FIN)) &&
|
1166 | f0cbd3ec | bellard | TCPS_HAVERCVDFIN(tp->t_state) == 0) {
|
1167 | f0cbd3ec | bellard | TCP_REASS(tp, ti, m, so, tiflags); |
1168 | f0cbd3ec | bellard | /*
|
1169 | f0cbd3ec | bellard | * Note the amount of data that peer has sent into
|
1170 | f0cbd3ec | bellard | * our window, in order to estimate the sender's
|
1171 | f0cbd3ec | bellard | * buffer size.
|
1172 | f0cbd3ec | bellard | */
|
1173 | f0cbd3ec | bellard | len = so->so_rcv.sb_datalen - (tp->rcv_adv - tp->rcv_nxt); |
1174 | f0cbd3ec | bellard | } else {
|
1175 | f0cbd3ec | bellard | m_free(m); |
1176 | f0cbd3ec | bellard | tiflags &= ~TH_FIN; |
1177 | f0cbd3ec | bellard | } |
1178 | f0cbd3ec | bellard | |
1179 | f0cbd3ec | bellard | /*
|
1180 | f0cbd3ec | bellard | * If FIN is received ACK the FIN and let the user know
|
1181 | f0cbd3ec | bellard | * that the connection is closing.
|
1182 | f0cbd3ec | bellard | */
|
1183 | f0cbd3ec | bellard | if (tiflags & TH_FIN) {
|
1184 | f0cbd3ec | bellard | if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
1185 | f0cbd3ec | bellard | /*
|
1186 | f0cbd3ec | bellard | * If we receive a FIN we can't send more data,
|
1187 | f0cbd3ec | bellard | * set it SS_FDRAIN
|
1188 | f0cbd3ec | bellard | * Shutdown the socket if there is no rx data in the
|
1189 | f0cbd3ec | bellard | * buffer.
|
1190 | f0cbd3ec | bellard | * soread() is called on completion of shutdown() and
|
1191 | f0cbd3ec | bellard | * will got to TCPS_LAST_ACK, and use tcp_output()
|
1192 | f0cbd3ec | bellard | * to send the FIN.
|
1193 | f0cbd3ec | bellard | */
|
1194 | f0cbd3ec | bellard | sofwdrain(so); |
1195 | 3b46e624 | ths | |
1196 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
1197 | f0cbd3ec | bellard | tp->rcv_nxt++; |
1198 | f0cbd3ec | bellard | } |
1199 | f0cbd3ec | bellard | switch (tp->t_state) {
|
1200 | f0cbd3ec | bellard | |
1201 | f0cbd3ec | bellard | /*
|
1202 | f0cbd3ec | bellard | * In SYN_RECEIVED and ESTABLISHED STATES
|
1203 | f0cbd3ec | bellard | * enter the CLOSE_WAIT state.
|
1204 | f0cbd3ec | bellard | */
|
1205 | f0cbd3ec | bellard | case TCPS_SYN_RECEIVED:
|
1206 | f0cbd3ec | bellard | case TCPS_ESTABLISHED:
|
1207 | f0cbd3ec | bellard | if(so->so_emu == EMU_CTL) /* no shutdown on socket */ |
1208 | f0cbd3ec | bellard | tp->t_state = TCPS_LAST_ACK; |
1209 | 5fafdf24 | ths | else
|
1210 | f0cbd3ec | bellard | tp->t_state = TCPS_CLOSE_WAIT; |
1211 | f0cbd3ec | bellard | break;
|
1212 | f0cbd3ec | bellard | |
1213 | f0cbd3ec | bellard | /*
|
1214 | f0cbd3ec | bellard | * If still in FIN_WAIT_1 STATE FIN has not been acked so
|
1215 | f0cbd3ec | bellard | * enter the CLOSING state.
|
1216 | f0cbd3ec | bellard | */
|
1217 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_1:
|
1218 | f0cbd3ec | bellard | tp->t_state = TCPS_CLOSING; |
1219 | f0cbd3ec | bellard | break;
|
1220 | f0cbd3ec | bellard | |
1221 | f0cbd3ec | bellard | /*
|
1222 | f0cbd3ec | bellard | * In FIN_WAIT_2 state enter the TIME_WAIT state,
|
1223 | 5fafdf24 | ths | * starting the time-wait timer, turning off the other
|
1224 | f0cbd3ec | bellard | * standard timers.
|
1225 | f0cbd3ec | bellard | */
|
1226 | f0cbd3ec | bellard | case TCPS_FIN_WAIT_2:
|
1227 | f0cbd3ec | bellard | tp->t_state = TCPS_TIME_WAIT; |
1228 | f0cbd3ec | bellard | tcp_canceltimers(tp); |
1229 | f0cbd3ec | bellard | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
|
1230 | f0cbd3ec | bellard | break;
|
1231 | f0cbd3ec | bellard | |
1232 | f0cbd3ec | bellard | /*
|
1233 | f0cbd3ec | bellard | * In TIME_WAIT state restart the 2 MSL time_wait timer.
|
1234 | f0cbd3ec | bellard | */
|
1235 | f0cbd3ec | bellard | case TCPS_TIME_WAIT:
|
1236 | f0cbd3ec | bellard | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
|
1237 | f0cbd3ec | bellard | break;
|
1238 | f0cbd3ec | bellard | } |
1239 | f0cbd3ec | bellard | } |
1240 | f0cbd3ec | bellard | |
1241 | f0cbd3ec | bellard | /*
|
1242 | f0cbd3ec | bellard | * If this is a small packet, then ACK now - with Nagel
|
1243 | f0cbd3ec | bellard | * congestion avoidance sender won't send more until
|
1244 | f0cbd3ec | bellard | * he gets an ACK.
|
1245 | 5fafdf24 | ths | *
|
1246 | f0cbd3ec | bellard | * See above.
|
1247 | f0cbd3ec | bellard | */
|
1248 | f0cbd3ec | bellard | if (ti->ti_len && (unsigned)ti->ti_len <= 5 && |
1249 | f0cbd3ec | bellard | ((struct tcpiphdr_2 *)ti)->first_char == (char)27) { |
1250 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
1251 | f0cbd3ec | bellard | } |
1252 | f0cbd3ec | bellard | |
1253 | f0cbd3ec | bellard | /*
|
1254 | f0cbd3ec | bellard | * Return any desired output.
|
1255 | f0cbd3ec | bellard | */
|
1256 | f0cbd3ec | bellard | if (needoutput || (tp->t_flags & TF_ACKNOW)) {
|
1257 | f0cbd3ec | bellard | (void) tcp_output(tp);
|
1258 | f0cbd3ec | bellard | } |
1259 | f0cbd3ec | bellard | return;
|
1260 | f0cbd3ec | bellard | |
1261 | f0cbd3ec | bellard | dropafterack:
|
1262 | f0cbd3ec | bellard | /*
|
1263 | f0cbd3ec | bellard | * Generate an ACK dropping incoming segment if it occupies
|
1264 | f0cbd3ec | bellard | * sequence space, where the ACK reflects our state.
|
1265 | f0cbd3ec | bellard | */
|
1266 | f0cbd3ec | bellard | if (tiflags & TH_RST)
|
1267 | f0cbd3ec | bellard | goto drop;
|
1268 | f0cbd3ec | bellard | m_freem(m); |
1269 | f0cbd3ec | bellard | tp->t_flags |= TF_ACKNOW; |
1270 | f0cbd3ec | bellard | (void) tcp_output(tp);
|
1271 | f0cbd3ec | bellard | return;
|
1272 | f0cbd3ec | bellard | |
1273 | f0cbd3ec | bellard | dropwithreset:
|
1274 | f0cbd3ec | bellard | /* reuses m if m!=NULL, m_free() unnecessary */
|
1275 | f0cbd3ec | bellard | if (tiflags & TH_ACK)
|
1276 | f0cbd3ec | bellard | tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);
|
1277 | f0cbd3ec | bellard | else {
|
1278 | f0cbd3ec | bellard | if (tiflags & TH_SYN) ti->ti_len++;
|
1279 | f0cbd3ec | bellard | tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,
|
1280 | f0cbd3ec | bellard | TH_RST|TH_ACK); |
1281 | f0cbd3ec | bellard | } |
1282 | f0cbd3ec | bellard | |
1283 | f0cbd3ec | bellard | return;
|
1284 | f0cbd3ec | bellard | |
1285 | f0cbd3ec | bellard | drop:
|
1286 | f0cbd3ec | bellard | /*
|
1287 | f0cbd3ec | bellard | * Drop space held by incoming segment and return.
|
1288 | f0cbd3ec | bellard | */
|
1289 | f0cbd3ec | bellard | m_free(m); |
1290 | f0cbd3ec | bellard | |
1291 | f0cbd3ec | bellard | return;
|
1292 | f0cbd3ec | bellard | } |
1293 | f0cbd3ec | bellard | |
1294 | 9634d903 | blueswir1 | static void |
1295 | 9634d903 | blueswir1 | tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt, struct tcpiphdr *ti) |
1296 | f0cbd3ec | bellard | { |
1297 | f0cbd3ec | bellard | u_int16_t mss; |
1298 | f0cbd3ec | bellard | int opt, optlen;
|
1299 | f0cbd3ec | bellard | |
1300 | f0cbd3ec | bellard | DEBUG_CALL("tcp_dooptions");
|
1301 | f0cbd3ec | bellard | DEBUG_ARGS((dfd," tp = %lx cnt=%i \n", (long )tp, cnt)); |
1302 | f0cbd3ec | bellard | |
1303 | f0cbd3ec | bellard | for (; cnt > 0; cnt -= optlen, cp += optlen) { |
1304 | f0cbd3ec | bellard | opt = cp[0];
|
1305 | f0cbd3ec | bellard | if (opt == TCPOPT_EOL)
|
1306 | f0cbd3ec | bellard | break;
|
1307 | f0cbd3ec | bellard | if (opt == TCPOPT_NOP)
|
1308 | f0cbd3ec | bellard | optlen = 1;
|
1309 | f0cbd3ec | bellard | else {
|
1310 | f0cbd3ec | bellard | optlen = cp[1];
|
1311 | f0cbd3ec | bellard | if (optlen <= 0) |
1312 | f0cbd3ec | bellard | break;
|
1313 | f0cbd3ec | bellard | } |
1314 | f0cbd3ec | bellard | switch (opt) {
|
1315 | f0cbd3ec | bellard | |
1316 | f0cbd3ec | bellard | default:
|
1317 | f0cbd3ec | bellard | continue;
|
1318 | f0cbd3ec | bellard | |
1319 | f0cbd3ec | bellard | case TCPOPT_MAXSEG:
|
1320 | f0cbd3ec | bellard | if (optlen != TCPOLEN_MAXSEG)
|
1321 | f0cbd3ec | bellard | continue;
|
1322 | f0cbd3ec | bellard | if (!(ti->ti_flags & TH_SYN))
|
1323 | f0cbd3ec | bellard | continue;
|
1324 | f0cbd3ec | bellard | memcpy((char *) &mss, (char *) cp + 2, sizeof(mss)); |
1325 | f0cbd3ec | bellard | NTOHS(mss); |
1326 | f0cbd3ec | bellard | (void) tcp_mss(tp, mss); /* sets t_maxseg */ |
1327 | f0cbd3ec | bellard | break;
|
1328 | f0cbd3ec | bellard | } |
1329 | f0cbd3ec | bellard | } |
1330 | f0cbd3ec | bellard | } |
1331 | f0cbd3ec | bellard | |
1332 | f0cbd3ec | bellard | |
1333 | f0cbd3ec | bellard | /*
|
1334 | f0cbd3ec | bellard | * Pull out of band byte out of a segment so
|
1335 | f0cbd3ec | bellard | * it doesn't appear in the user's data queue.
|
1336 | f0cbd3ec | bellard | * It is still reflected in the segment length for
|
1337 | f0cbd3ec | bellard | * sequencing purposes.
|
1338 | f0cbd3ec | bellard | */
|
1339 | f0cbd3ec | bellard | |
1340 | f0cbd3ec | bellard | #ifdef notdef
|
1341 | f0cbd3ec | bellard | |
1342 | f0cbd3ec | bellard | void
|
1343 | f0cbd3ec | bellard | tcp_pulloutofband(so, ti, m) |
1344 | f0cbd3ec | bellard | struct socket *so;
|
1345 | f0cbd3ec | bellard | struct tcpiphdr *ti;
|
1346 | f0cbd3ec | bellard | register struct mbuf *m; |
1347 | f0cbd3ec | bellard | { |
1348 | f0cbd3ec | bellard | int cnt = ti->ti_urp - 1; |
1349 | 5fafdf24 | ths | |
1350 | f0cbd3ec | bellard | while (cnt >= 0) { |
1351 | f0cbd3ec | bellard | if (m->m_len > cnt) {
|
1352 | f0cbd3ec | bellard | char *cp = mtod(m, caddr_t) + cnt;
|
1353 | f0cbd3ec | bellard | struct tcpcb *tp = sototcpcb(so);
|
1354 | f0cbd3ec | bellard | |
1355 | f0cbd3ec | bellard | tp->t_iobc = *cp; |
1356 | f0cbd3ec | bellard | tp->t_oobflags |= TCPOOB_HAVEDATA; |
1357 | f0cbd3ec | bellard | memcpy(sp, cp+1, (unsigned)(m->m_len - cnt - 1)); |
1358 | f0cbd3ec | bellard | m->m_len--; |
1359 | f0cbd3ec | bellard | return;
|
1360 | f0cbd3ec | bellard | } |
1361 | f0cbd3ec | bellard | cnt -= m->m_len; |
1362 | f0cbd3ec | bellard | m = m->m_next; /* XXX WRONG! Fix it! */
|
1363 | f0cbd3ec | bellard | if (m == 0) |
1364 | f0cbd3ec | bellard | break;
|
1365 | f0cbd3ec | bellard | } |
1366 | f0cbd3ec | bellard | panic("tcp_pulloutofband");
|
1367 | f0cbd3ec | bellard | } |
1368 | f0cbd3ec | bellard | |
1369 | f0cbd3ec | bellard | #endif /* notdef */ |
1370 | f0cbd3ec | bellard | |
1371 | f0cbd3ec | bellard | /*
|
1372 | f0cbd3ec | bellard | * Collect new round-trip time estimate
|
1373 | f0cbd3ec | bellard | * and update averages and current timeout.
|
1374 | f0cbd3ec | bellard | */
|
1375 | f0cbd3ec | bellard | |
1376 | 9634d903 | blueswir1 | static void |
1377 | 9634d903 | blueswir1 | tcp_xmit_timer(register struct tcpcb *tp, int rtt) |
1378 | f0cbd3ec | bellard | { |
1379 | f0cbd3ec | bellard | register short delta; |
1380 | f0cbd3ec | bellard | |
1381 | f0cbd3ec | bellard | DEBUG_CALL("tcp_xmit_timer");
|
1382 | f0cbd3ec | bellard | DEBUG_ARG("tp = %lx", (long)tp); |
1383 | f0cbd3ec | bellard | DEBUG_ARG("rtt = %d", rtt);
|
1384 | 5fafdf24 | ths | |
1385 | f0cbd3ec | bellard | if (tp->t_srtt != 0) { |
1386 | f0cbd3ec | bellard | /*
|
1387 | f0cbd3ec | bellard | * srtt is stored as fixed point with 3 bits after the
|
1388 | f0cbd3ec | bellard | * binary point (i.e., scaled by 8). The following magic
|
1389 | f0cbd3ec | bellard | * is equivalent to the smoothing algorithm in rfc793 with
|
1390 | f0cbd3ec | bellard | * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed
|
1391 | f0cbd3ec | bellard | * point). Adjust rtt to origin 0.
|
1392 | f0cbd3ec | bellard | */
|
1393 | f0cbd3ec | bellard | delta = rtt - 1 - (tp->t_srtt >> TCP_RTT_SHIFT);
|
1394 | f0cbd3ec | bellard | if ((tp->t_srtt += delta) <= 0) |
1395 | f0cbd3ec | bellard | tp->t_srtt = 1;
|
1396 | f0cbd3ec | bellard | /*
|
1397 | f0cbd3ec | bellard | * We accumulate a smoothed rtt variance (actually, a
|
1398 | f0cbd3ec | bellard | * smoothed mean difference), then set the retransmit
|
1399 | f0cbd3ec | bellard | * timer to smoothed rtt + 4 times the smoothed variance.
|
1400 | f0cbd3ec | bellard | * rttvar is stored as fixed point with 2 bits after the
|
1401 | f0cbd3ec | bellard | * binary point (scaled by 4). The following is
|
1402 | f0cbd3ec | bellard | * equivalent to rfc793 smoothing with an alpha of .75
|
1403 | f0cbd3ec | bellard | * (rttvar = rttvar*3/4 + |delta| / 4). This replaces
|
1404 | f0cbd3ec | bellard | * rfc793's wired-in beta.
|
1405 | f0cbd3ec | bellard | */
|
1406 | f0cbd3ec | bellard | if (delta < 0) |
1407 | f0cbd3ec | bellard | delta = -delta; |
1408 | f0cbd3ec | bellard | delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT); |
1409 | f0cbd3ec | bellard | if ((tp->t_rttvar += delta) <= 0) |
1410 | f0cbd3ec | bellard | tp->t_rttvar = 1;
|
1411 | f0cbd3ec | bellard | } else {
|
1412 | 5fafdf24 | ths | /*
|
1413 | f0cbd3ec | bellard | * No rtt measurement yet - use the unsmoothed rtt.
|
1414 | f0cbd3ec | bellard | * Set the variance to half the rtt (so our first
|
1415 | f0cbd3ec | bellard | * retransmit happens at 3*rtt).
|
1416 | f0cbd3ec | bellard | */
|
1417 | f0cbd3ec | bellard | tp->t_srtt = rtt << TCP_RTT_SHIFT; |
1418 | f0cbd3ec | bellard | tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
|
1419 | f0cbd3ec | bellard | } |
1420 | f0cbd3ec | bellard | tp->t_rtt = 0;
|
1421 | f0cbd3ec | bellard | tp->t_rxtshift = 0;
|
1422 | f0cbd3ec | bellard | |
1423 | f0cbd3ec | bellard | /*
|
1424 | f0cbd3ec | bellard | * the retransmit should happen at rtt + 4 * rttvar.
|
1425 | f0cbd3ec | bellard | * Because of the way we do the smoothing, srtt and rttvar
|
1426 | f0cbd3ec | bellard | * will each average +1/2 tick of bias. When we compute
|
1427 | f0cbd3ec | bellard | * the retransmit timer, we want 1/2 tick of rounding and
|
1428 | f0cbd3ec | bellard | * 1 extra tick because of +-1/2 tick uncertainty in the
|
1429 | f0cbd3ec | bellard | * firing of the timer. The bias will give us exactly the
|
1430 | f0cbd3ec | bellard | * 1.5 tick we need. But, because the bias is
|
1431 | f0cbd3ec | bellard | * statistical, we have to test that we don't drop below
|
1432 | f0cbd3ec | bellard | * the minimum feasible timer (which is 2 ticks).
|
1433 | f0cbd3ec | bellard | */
|
1434 | f0cbd3ec | bellard | TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp), |
1435 | f0cbd3ec | bellard | (short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */ |
1436 | 5fafdf24 | ths | |
1437 | f0cbd3ec | bellard | /*
|
1438 | f0cbd3ec | bellard | * We received an ack for a packet that wasn't retransmitted;
|
1439 | f0cbd3ec | bellard | * it is probably safe to discard any error indications we've
|
1440 | f0cbd3ec | bellard | * received recently. This isn't quite right, but close enough
|
1441 | f0cbd3ec | bellard | * for now (a route might have failed after we sent a segment,
|
1442 | f0cbd3ec | bellard | * and the return path might not be symmetrical).
|
1443 | f0cbd3ec | bellard | */
|
1444 | f0cbd3ec | bellard | tp->t_softerror = 0;
|
1445 | f0cbd3ec | bellard | } |
1446 | f0cbd3ec | bellard | |
1447 | f0cbd3ec | bellard | /*
|
1448 | f0cbd3ec | bellard | * Determine a reasonable value for maxseg size.
|
1449 | f0cbd3ec | bellard | * If the route is known, check route for mtu.
|
1450 | f0cbd3ec | bellard | * If none, use an mss that can be handled on the outgoing
|
1451 | f0cbd3ec | bellard | * interface without forcing IP to fragment; if bigger than
|
1452 | f0cbd3ec | bellard | * an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES
|
1453 | f0cbd3ec | bellard | * to utilize large mbufs. If no route is found, route has no mtu,
|
1454 | f0cbd3ec | bellard | * or the destination isn't local, use a default, hopefully conservative
|
1455 | f0cbd3ec | bellard | * size (usually 512 or the default IP max size, but no more than the mtu
|
1456 | f0cbd3ec | bellard | * of the interface), as we can't discover anything about intervening
|
1457 | f0cbd3ec | bellard | * gateways or networks. We also initialize the congestion/slow start
|
1458 | f0cbd3ec | bellard | * window to be a single segment if the destination isn't local.
|
1459 | f0cbd3ec | bellard | * While looking at the routing entry, we also initialize other path-dependent
|
1460 | f0cbd3ec | bellard | * parameters from pre-set or cached values in the routing entry.
|
1461 | f0cbd3ec | bellard | */
|
1462 | f0cbd3ec | bellard | |
1463 | f0cbd3ec | bellard | int
|
1464 | 511d2b14 | blueswir1 | tcp_mss(struct tcpcb *tp, u_int offer)
|
1465 | f0cbd3ec | bellard | { |
1466 | f0cbd3ec | bellard | struct socket *so = tp->t_socket;
|
1467 | f0cbd3ec | bellard | int mss;
|
1468 | 5fafdf24 | ths | |
1469 | f0cbd3ec | bellard | DEBUG_CALL("tcp_mss");
|
1470 | f0cbd3ec | bellard | DEBUG_ARG("tp = %lx", (long)tp); |
1471 | f0cbd3ec | bellard | DEBUG_ARG("offer = %d", offer);
|
1472 | 5fafdf24 | ths | |
1473 | 9634d903 | blueswir1 | mss = min(IF_MTU, IF_MRU) - sizeof(struct tcpiphdr); |
1474 | f0cbd3ec | bellard | if (offer)
|
1475 | f0cbd3ec | bellard | mss = min(mss, offer); |
1476 | f0cbd3ec | bellard | mss = max(mss, 32);
|
1477 | f0cbd3ec | bellard | if (mss < tp->t_maxseg || offer != 0) |
1478 | f0cbd3ec | bellard | tp->t_maxseg = mss; |
1479 | 5fafdf24 | ths | |
1480 | f0cbd3ec | bellard | tp->snd_cwnd = mss; |
1481 | 5fafdf24 | ths | |
1482 | 9634d903 | blueswir1 | sbreserve(&so->so_snd, TCP_SNDSPACE + ((TCP_SNDSPACE % mss) ? |
1483 | 9634d903 | blueswir1 | (mss - (TCP_SNDSPACE % mss)) : |
1484 | 9634d903 | blueswir1 | 0));
|
1485 | 9634d903 | blueswir1 | sbreserve(&so->so_rcv, TCP_RCVSPACE + ((TCP_RCVSPACE % mss) ? |
1486 | 9634d903 | blueswir1 | (mss - (TCP_RCVSPACE % mss)) : |
1487 | 9634d903 | blueswir1 | 0));
|
1488 | 5fafdf24 | ths | |
1489 | f0cbd3ec | bellard | DEBUG_MISC((dfd, " returning mss = %d\n", mss));
|
1490 | 5fafdf24 | ths | |
1491 | f0cbd3ec | bellard | return mss;
|
1492 | f0cbd3ec | bellard | } |