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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_output.c@ 1

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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 <slirp.h>
46
47u_int16_t ip_id;
48
49/*
50 * IP output. The packet in mbuf chain m contains a skeletal IP
51 * header (with len, off, ttl, proto, tos, src, dst).
52 * The mbuf chain containing the packet will be freed.
53 * The mbuf opt, if present, will not be freed.
54 */
55int
56ip_output(so, m0)
57 struct socket *so;
58 struct mbuf *m0;
59{
60 register struct ip *ip;
61 register struct mbuf *m = m0;
62 register int hlen = sizeof(struct ip );
63 int len, off, error = 0;
64
65 DEBUG_CALL("ip_output");
66 DEBUG_ARG("so = %lx", (long)so);
67 DEBUG_ARG("m0 = %lx", (long)m0);
68
69 /* We do no options */
70/* if (opt) {
71 * m = ip_insertoptions(m, opt, &len);
72 * hlen = len;
73 * }
74 */
75 ip = mtod(m, struct ip *);
76 /*
77 * Fill in IP header.
78 */
79 ip->ip_v = IPVERSION;
80 ip->ip_off &= IP_DF;
81 ip->ip_id = htons(ip_id++);
82 ip->ip_hl = hlen >> 2;
83 ipstat.ips_localout++;
84
85 /*
86 * Verify that we have any chance at all of being able to queue
87 * the packet or packet fragments
88 */
89 /* XXX Hmmm... */
90/* if (if_queued > if_thresh && towrite <= 0) {
91 * error = ENOBUFS;
92 * goto bad;
93 * }
94 */
95
96 /*
97 * If small enough for interface, can just send directly.
98 */
99 if ((u_int16_t)ip->ip_len <= if_mtu) {
100 ip->ip_len = htons((u_int16_t)ip->ip_len);
101 ip->ip_off = htons((u_int16_t)ip->ip_off);
102 ip->ip_sum = 0;
103 ip->ip_sum = cksum(m, hlen);
104
105 if_output(so, m);
106 goto done;
107 }
108
109 /*
110 * Too large for interface; fragment if possible.
111 * Must be able to put at least 8 bytes per fragment.
112 */
113 if (ip->ip_off & IP_DF) {
114 error = -1;
115 ipstat.ips_cantfrag++;
116 goto bad;
117 }
118
119 len = (if_mtu - hlen) &~ 7; /* ip databytes per packet */
120 if (len < 8) {
121 error = -1;
122 goto bad;
123 }
124
125 {
126 int mhlen, firstlen = len;
127 struct mbuf **mnext = &m->m_nextpkt;
128
129 /*
130 * Loop through length of segment after first fragment,
131 * make new header and copy data of each part and link onto chain.
132 */
133 m0 = m;
134 mhlen = sizeof (struct ip);
135 for (off = hlen + len; off < (u_int16_t)ip->ip_len; off += len) {
136 register struct ip *mhip;
137 m = m_get();
138 if (m == 0) {
139 error = -1;
140 ipstat.ips_odropped++;
141 goto sendorfree;
142 }
143 m->m_data += if_maxlinkhdr;
144 mhip = mtod(m, struct ip *);
145 *mhip = *ip;
146
147 /* No options */
148/* if (hlen > sizeof (struct ip)) {
149 * mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
150 * mhip->ip_hl = mhlen >> 2;
151 * }
152 */
153 m->m_len = mhlen;
154 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
155 if (ip->ip_off & IP_MF)
156 mhip->ip_off |= IP_MF;
157 if (off + len >= (u_int16_t)ip->ip_len)
158 len = (u_int16_t)ip->ip_len - off;
159 else
160 mhip->ip_off |= IP_MF;
161 mhip->ip_len = htons((u_int16_t)(len + mhlen));
162
163 if (m_copy(m, m0, off, len) < 0) {
164 error = -1;
165 goto sendorfree;
166 }
167
168 mhip->ip_off = htons((u_int16_t)mhip->ip_off);
169 mhip->ip_sum = 0;
170 mhip->ip_sum = cksum(m, mhlen);
171 *mnext = m;
172 mnext = &m->m_nextpkt;
173 ipstat.ips_ofragments++;
174 }
175 /*
176 * Update first fragment by trimming what's been copied out
177 * and updating header, then send each fragment (in order).
178 */
179 m = m0;
180 m_adj(m, hlen + firstlen - (u_int16_t)ip->ip_len);
181 ip->ip_len = htons((u_int16_t)m->m_len);
182 ip->ip_off = htons((u_int16_t)(ip->ip_off | IP_MF));
183 ip->ip_sum = 0;
184 ip->ip_sum = cksum(m, hlen);
185sendorfree:
186 for (m = m0; m; m = m0) {
187 m0 = m->m_nextpkt;
188 m->m_nextpkt = 0;
189 if (error == 0)
190 if_output(so, m);
191 else
192 m_freem(m);
193 }
194
195 if (error == 0)
196 ipstat.ips_fragmented++;
197 }
198
199done:
200 return (error);
201
202bad:
203 m_freem(m0);
204 goto done;
205}
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