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/*
* 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>
u_int16_t ip_id;
/* 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)
{
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;
STAT(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;
STAT(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 == NULL) {
error = -1;
STAT(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;
STAT(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 = NULL;
if (error == 0)
if_output(so, m);
else
m_freem(m);
}
if (error == 0)
STAT(ipstat.ips_fragmented++);
}
done:
return (error);
bad:
m_freem(m0);
goto done;
}
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