vde-2/slirpvde/ip_output.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1988, 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)ip_output.c 8.3 (Berkeley) 1/21/94
  34  * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
  35  */
  36
  37 /*
  38  * Changes and additions relating to SLiRP are
  39  * Copyright (c) 1995 Danny Gasparovski.
  40  *
  41  * Please read the file COPYRIGHT for the
  42  * terms and conditions of the copyright.
  43  */
  44
  45 #include <config.h>
  46 #include <slirp.h>
  47
  48 u_int16_t ip_id;
  49
  50 /*
  51  * IP output.  The packet in mbuf chain m contains a skeletal IP
  52  * header (with len, off, ttl, proto, tos, src, dst).
  53  * The mbuf chain containing the packet will be freed.
  54  * The mbuf opt, if present, will not be freed.
  55  */
  56 int
  57 ip_output(so, m0)
  58         struct socket *so;
  59         struct mbuf *m0;
  60 {
  61         register struct ip *ip;
  62         register struct mbuf *m = m0;
  63         register int hlen = sizeof(struct ip );
  64         int len, off, error = 0;
  65
  66         DEBUG_CALL("ip_output");
  67         DEBUG_ARG("so = %lx", (long)so);
  68         DEBUG_ARG("m0 = %lx", (long)m0);
  69
  70         /* We do no options */
  71 /*      if (opt) {
  72  *              m = ip_insertoptions(m, opt, &len);
  73  *              hlen = len;
  74  *      }
  75  */
  76         ip = mtod(m, struct ip *);
  77         /*
  78          * Fill in IP header.
  79          */
  80         ip->ip_v = IPVERSION;
  81         ip->ip_off &= IP_DF;
  82         ip->ip_id = htons(ip_id++);
  83         ip->ip_hl = hlen >> 2;
  84         ipstat.ips_localout++;
  85
  86         /*
  87          * Verify that we have any chance at all of being able to queue
  88          *      the packet or packet fragments
  89          */
  90         /* XXX Hmmm... */
  91 /*      if (if_queued > if_thresh && towrite <= 0) {
  92  *              error = ENOBUFS;
  93  *              goto bad;
  94  *      }
  95  */
  96
  97         /*
  98          * If small enough for interface, can just send directly.
  99          */
 100         if ((u_int16_t)ip->ip_len <= if_mtu) {
 101                 ip->ip_len = htons((u_int16_t)ip->ip_len);
 102                 ip->ip_off = htons((u_int16_t)ip->ip_off);
 103                 ip->ip_sum = 0;
 104                 ip->ip_sum = cksum(m, hlen);
 105
 106                 if_output(so, m);
 107                 goto done;
 108         }
 109
 110         /*
 111          * Too large for interface; fragment if possible.
 112          * Must be able to put at least 8 bytes per fragment.
 113          */
 114         if (ip->ip_off & IP_DF) {
 115                 error = -1;
 116                 ipstat.ips_cantfrag++;
 117                 goto bad;
 118         }
 119
 120         len = (if_mtu - hlen) &~ 7;       /* ip databytes per packet */
 121         if (len < 8) {
 122                 error = -1;
 123                 goto bad;
 124         }
 125
 126     {
 127         int mhlen, firstlen = len;
 128         struct mbuf **mnext = &m->m_nextpkt;
 129
 130         /*
 131          * Loop through length of segment after first fragment,
 132          * make new header and copy data of each part and link onto chain.
 133          */
 134         m0 = m;
 135         mhlen = sizeof (struct ip);
 136         for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len) {
 137           register struct ip *mhip;
 138           m = m_get();
 139           if (m == 0) {
 140             error = -1;
 141             ipstat.ips_odropped++;
 142             goto sendorfree;
 143           }
 144           m->m_data += if_maxlinkhdr;
 145           mhip = mtod(m, struct ip *);
 146           *mhip = *ip;
 147
 148                 /* No options */
 149 /*              if (hlen > sizeof (struct ip)) {
 150  *                      mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
 151  *                      mhip->ip_hl = mhlen >> 2;
 152  *              }
 153  */
 154           m->m_len = mhlen;
 155           mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
 156           if (ip->ip_off & IP_MF)
 157             mhip->ip_off |= IP_MF;
 158           if (off + len >= (u_int16_t)ip->ip_len)
 159             len = (u_int16_t)ip->ip_len - off;
 160           else
 161             mhip->ip_off |= IP_MF;
 162           mhip->ip_len = htons((u_int16_t)(len + mhlen));
 163
 164           if (m_copy(m, m0, off, len) < 0) {
 165             error = -1;
 166             goto sendorfree;
 167           }
 168
 169           mhip->ip_off = htons((u_int16_t)mhip->ip_off);
 170           mhip->ip_sum = 0;
 171           mhip->ip_sum = cksum(m, mhlen);
 172           *mnext = m;
 173           mnext = &m->m_nextpkt;
 174           ipstat.ips_ofragments++;
 175         }
 176         /*
 177          * Update first fragment by trimming what's been copied out
 178          * and updating header, then send each fragment (in order).
 179          */
 180         m = m0;
 181         m_adj(m, hlen + firstlen - (u_int16_t)ip->ip_len);
 182         ip->ip_len = htons((u_int16_t)m->m_len);
 183         ip->ip_off = htons((u_int16_t)(ip->ip_off | IP_MF));
 184         ip->ip_sum = 0;
 185         ip->ip_sum = cksum(m, hlen);
 186 sendorfree:
 187         for (m = m0; m; m = m0) {
 188                 m0 = m->m_nextpkt;
 189                 m->m_nextpkt = 0;
 190                 if (error == 0)
 191                         if_output(so, m);
 192                 else
 193                         m_freem(m);
 194         }
 195
 196         if (error == 0)
 197                 ipstat.ips_fragmented++;
 198     }
 199
 200 done:
 201         return (error);
 202
 203 bad:
 204         m_freem(m0);
 205         goto done;
 206 }