/* * 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. */intip_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;}