1 | /*
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2 | * Copyright (c) 1982, 1986, 1988, 1990, 1993
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3 | * The Regents of the University of California. All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. All advertising materials mentioning features or use of this software
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14 | * must display the following acknowledgement:
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15 | * This product includes software developed by the University of
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16 | * California, Berkeley and its contributors.
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17 | * 4. Neither the name of the University nor the names of its contributors
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18 | * may be used to endorse or promote products derived from this software
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19 | * without specific prior written permission.
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20 | *
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21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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31 | * SUCH DAMAGE.
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32 | *
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33 | * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
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34 | * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
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35 | */
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36 |
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37 | /*
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38 | * Changes and additions relating to SLiRP are
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39 | * Copyright (c) 1995 Danny Gasparovski.
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40 | *
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41 | * Please read the file COPYRIGHT for the
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42 | * terms and conditions of the copyright.
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43 | */
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44 |
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45 | #include <slirp.h>
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46 |
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47 | u_int16_t ip_id;
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48 |
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49 | /*
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50 | * IP output. The packet in mbuf chain m contains a skeletal IP
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51 | * header (with len, off, ttl, proto, tos, src, dst).
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52 | * The mbuf chain containing the packet will be freed.
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53 | * The mbuf opt, if present, will not be freed.
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54 | */
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55 | int
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56 | ip_output(so, m0)
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57 | struct socket *so;
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58 | struct mbuf *m0;
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59 | {
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60 | register struct ip *ip;
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61 | register struct mbuf *m = m0;
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62 | register int hlen = sizeof(struct ip );
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63 | int len, off, error = 0;
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64 |
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65 | DEBUG_CALL("ip_output");
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66 | DEBUG_ARG("so = %lx", (long)so);
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67 | DEBUG_ARG("m0 = %lx", (long)m0);
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68 |
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69 | /* We do no options */
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70 | /* if (opt) {
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71 | * m = ip_insertoptions(m, opt, &len);
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72 | * hlen = len;
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73 | * }
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74 | */
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75 | ip = mtod(m, struct ip *);
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76 | /*
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77 | * Fill in IP header.
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78 | */
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79 | ip->ip_v = IPVERSION;
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80 | ip->ip_off &= IP_DF;
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81 | ip->ip_id = htons(ip_id++);
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82 | ip->ip_hl = hlen >> 2;
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83 | ipstat.ips_localout++;
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84 |
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85 | /*
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86 | * Verify that we have any chance at all of being able to queue
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87 | * the packet or packet fragments
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88 | */
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89 | /* XXX Hmmm... */
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90 | /* if (if_queued > if_thresh && towrite <= 0) {
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91 | * error = ENOBUFS;
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92 | * goto bad;
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93 | * }
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94 | */
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95 |
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96 | /*
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97 | * If small enough for interface, can just send directly.
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98 | */
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99 | if ((u_int16_t)ip->ip_len <= if_mtu) {
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100 | ip->ip_len = htons((u_int16_t)ip->ip_len);
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101 | ip->ip_off = htons((u_int16_t)ip->ip_off);
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102 | ip->ip_sum = 0;
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103 | ip->ip_sum = cksum(m, hlen);
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104 |
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105 | if_output(so, m);
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106 | goto done;
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107 | }
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108 |
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109 | /*
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110 | * Too large for interface; fragment if possible.
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111 | * Must be able to put at least 8 bytes per fragment.
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112 | */
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113 | if (ip->ip_off & IP_DF) {
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114 | error = -1;
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115 | ipstat.ips_cantfrag++;
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116 | goto bad;
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117 | }
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118 |
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119 | len = (if_mtu - hlen) &~ 7; /* ip databytes per packet */
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120 | if (len < 8) {
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121 | error = -1;
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122 | goto bad;
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123 | }
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124 |
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125 | {
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126 | int mhlen, firstlen = len;
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127 | struct mbuf **mnext = &m->m_nextpkt;
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128 |
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129 | /*
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130 | * Loop through length of segment after first fragment,
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131 | * make new header and copy data of each part and link onto chain.
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132 | */
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133 | m0 = m;
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134 | mhlen = sizeof (struct ip);
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135 | for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len) {
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136 | register struct ip *mhip;
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137 | m = m_get();
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138 | if (m == 0) {
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139 | error = -1;
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140 | ipstat.ips_odropped++;
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141 | goto sendorfree;
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142 | }
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143 | m->m_data += if_maxlinkhdr;
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144 | mhip = mtod(m, struct ip *);
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145 | *mhip = *ip;
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146 |
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147 | /* No options */
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148 | /* if (hlen > sizeof (struct ip)) {
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149 | * mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
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150 | * mhip->ip_hl = mhlen >> 2;
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151 | * }
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152 | */
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153 | m->m_len = mhlen;
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154 | mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
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155 | if (ip->ip_off & IP_MF)
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156 | mhip->ip_off |= IP_MF;
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157 | if (off + len >= (u_int16_t)ip->ip_len)
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158 | len = (u_int16_t)ip->ip_len - off;
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159 | else
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160 | mhip->ip_off |= IP_MF;
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161 | mhip->ip_len = htons((u_int16_t)(len + mhlen));
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162 |
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163 | if (m_copy(m, m0, off, len) < 0) {
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164 | error = -1;
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165 | goto sendorfree;
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166 | }
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167 |
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168 | mhip->ip_off = htons((u_int16_t)mhip->ip_off);
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169 | mhip->ip_sum = 0;
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170 | mhip->ip_sum = cksum(m, mhlen);
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171 | *mnext = m;
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172 | mnext = &m->m_nextpkt;
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173 | ipstat.ips_ofragments++;
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174 | }
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175 | /*
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176 | * Update first fragment by trimming what's been copied out
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177 | * and updating header, then send each fragment (in order).
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178 | */
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179 | m = m0;
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180 | m_adj(m, hlen + firstlen - (u_int16_t)ip->ip_len);
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181 | ip->ip_len = htons((u_int16_t)m->m_len);
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182 | ip->ip_off = htons((u_int16_t)(ip->ip_off | IP_MF));
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183 | ip->ip_sum = 0;
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184 | ip->ip_sum = cksum(m, hlen);
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185 | sendorfree:
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186 | for (m = m0; m; m = m0) {
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187 | m0 = m->m_nextpkt;
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188 | m->m_nextpkt = 0;
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189 | if (error == 0)
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190 | if_output(so, m);
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191 | else
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192 | m_freem(m);
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193 | }
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194 |
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195 | if (error == 0)
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196 | ipstat.ips_fragmented++;
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197 | }
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198 |
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199 | done:
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200 | return (error);
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201 |
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202 | bad:
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203 | m_freem(m0);
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204 | goto done;
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205 | }
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