linux-user: stack_base is now mandatory on all targets
[qemu.git] / slirp / 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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
30 * ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
31 */
32
33 /*
34 * Changes and additions relating to SLiRP are
35 * Copyright (c) 1995 Danny Gasparovski.
36 *
37 * Please read the file COPYRIGHT for the
38 * terms and conditions of the copyright.
39 */
40
41 #include <slirp.h>
42
43 /* Number of packets queued before we start sending
44 * (to prevent allocing too many mbufs) */
45 #define IF_THRESH 10
46
47 /*
48 * IP output. The packet in mbuf chain m contains a skeletal IP
49 * header (with len, off, ttl, proto, tos, src, dst).
50 * The mbuf chain containing the packet will be freed.
51 * The mbuf opt, if present, will not be freed.
52 */
53 int
54 ip_output(struct socket *so, struct mbuf *m0)
55 {
56 Slirp *slirp = m0->slirp;
57 register struct ip *ip;
58 register struct mbuf *m = m0;
59 register int hlen = sizeof(struct ip );
60 int len, off, error = 0;
61
62 DEBUG_CALL("ip_output");
63 DEBUG_ARG("so = %lx", (long)so);
64 DEBUG_ARG("m0 = %lx", (long)m0);
65
66 ip = mtod(m, struct ip *);
67 /*
68 * Fill in IP header.
69 */
70 ip->ip_v = IPVERSION;
71 ip->ip_off &= IP_DF;
72 ip->ip_id = htons(slirp->ip_id++);
73 ip->ip_hl = hlen >> 2;
74
75 /*
76 * If small enough for interface, can just send directly.
77 */
78 if ((uint16_t)ip->ip_len <= IF_MTU) {
79 ip->ip_len = htons((uint16_t)ip->ip_len);
80 ip->ip_off = htons((uint16_t)ip->ip_off);
81 ip->ip_sum = 0;
82 ip->ip_sum = cksum(m, hlen);
83
84 if_output(so, m);
85 goto done;
86 }
87
88 /*
89 * Too large for interface; fragment if possible.
90 * Must be able to put at least 8 bytes per fragment.
91 */
92 if (ip->ip_off & IP_DF) {
93 error = -1;
94 goto bad;
95 }
96
97 len = (IF_MTU - hlen) &~ 7; /* ip databytes per packet */
98 if (len < 8) {
99 error = -1;
100 goto bad;
101 }
102
103 {
104 int mhlen, firstlen = len;
105 struct mbuf **mnext = &m->m_nextpkt;
106
107 /*
108 * Loop through length of segment after first fragment,
109 * make new header and copy data of each part and link onto chain.
110 */
111 m0 = m;
112 mhlen = sizeof (struct ip);
113 for (off = hlen + len; off < (uint16_t)ip->ip_len; off += len) {
114 register struct ip *mhip;
115 m = m_get(slirp);
116 if (m == NULL) {
117 error = -1;
118 goto sendorfree;
119 }
120 m->m_data += IF_MAXLINKHDR;
121 mhip = mtod(m, struct ip *);
122 *mhip = *ip;
123
124 m->m_len = mhlen;
125 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
126 if (ip->ip_off & IP_MF)
127 mhip->ip_off |= IP_MF;
128 if (off + len >= (uint16_t)ip->ip_len)
129 len = (uint16_t)ip->ip_len - off;
130 else
131 mhip->ip_off |= IP_MF;
132 mhip->ip_len = htons((uint16_t)(len + mhlen));
133
134 if (m_copy(m, m0, off, len) < 0) {
135 error = -1;
136 goto sendorfree;
137 }
138
139 mhip->ip_off = htons((uint16_t)mhip->ip_off);
140 mhip->ip_sum = 0;
141 mhip->ip_sum = cksum(m, mhlen);
142 *mnext = m;
143 mnext = &m->m_nextpkt;
144 }
145 /*
146 * Update first fragment by trimming what's been copied out
147 * and updating header, then send each fragment (in order).
148 */
149 m = m0;
150 m_adj(m, hlen + firstlen - (uint16_t)ip->ip_len);
151 ip->ip_len = htons((uint16_t)m->m_len);
152 ip->ip_off = htons((uint16_t)(ip->ip_off | IP_MF));
153 ip->ip_sum = 0;
154 ip->ip_sum = cksum(m, hlen);
155 sendorfree:
156 for (m = m0; m; m = m0) {
157 m0 = m->m_nextpkt;
158 m->m_nextpkt = NULL;
159 if (error == 0)
160 if_output(so, m);
161 else
162 m_free(m);
163 }
164 }
165
166 done:
167 return (error);
168
169 bad:
170 m_free(m0);
171 goto done;
172 }