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