src/slirp/ip_output.c

/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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>

u_int16_t ip_id;

/*
 * 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(so, m0)
        struct socket *so;
        struct mbuf *m0;
{
        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);
        
        /* We do no options */
/*      if (opt) {
 *              m = ip_insertoptions(m, opt, &len);
 *              hlen = len;
 *      }
 */
        ip = mtod(m, struct ip *);
        /*
         * Fill in IP header.
         */
        ip->ip_v = IPVERSION;
        ip->ip_off &= IP_DF;
        ip->ip_id = htons(ip_id++);
        ip->ip_hl = hlen >> 2;
        ipstat.ips_localout++;

        /*
         * Verify that we have any chance at all of being able to queue
         *      the packet or packet fragments
         */
        /* XXX Hmmm... */
/*      if (if_queued > if_thresh && towrite <= 0) {
 *              error = ENOBUFS;
 *              goto bad;
 *      }
 */
        
        /*
         * 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;
                ipstat.ips_cantfrag++;
                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();
          if (m == 0) {
            error = -1;
            ipstat.ips_odropped++;
            goto sendorfree;
          }
          m->m_data += if_maxlinkhdr;
          mhip = mtod(m, struct ip *);
          *mhip = *ip;
                
                /* No options */
/*              if (hlen > sizeof (struct ip)) {
 *                      mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
 *                      mhip->ip_hl = mhlen >> 2;
 *              }
 */
          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;
          ipstat.ips_ofragments++;
        }
        /*
         * 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 = 0;
                if (error == 0)
                        if_output(so, m);
                else
                        m_freem(m);
        }

        if (error == 0)
                ipstat.ips_fragmented++;
    }

done:
        return (error);

bad:
        m_freem(m0);
        goto done;
}
Revision:	1.1
Committed:	2005-05-13T09:00:59Z (19 years, 1 month ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-19, nigel-build-17
Log Message:	slirp user mode network emulation code from qemu
#	User	Rev	Content
1	gbeauche	1.1	/*
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
47			u_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			*/
55			int
56			ip_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);
185			sendorfree:
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
199			done:
200			return (error);
201
202			bad:
203			m_freem(m0);
204			goto done;
205			}