ip_output.c

VxWorks网络部分的源代码

/* ip_output.c - internet output routines */

/* Copyright 1984-1997 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
 * 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
 */

/*
modification history
--------------------
01o,03sep98,n_s  fixed fragmentation problem for mcast and bcast. spr #21071.
01n,26aug98,n_s  added return val check for mBufClGet in ip_ctloutput and
                 ip_getmoptions. spr #22238.
01m,09jan98,vin  changed IP_CKSUM_SEND_MASK to IP_DO_CHECKSUM_SND
01l,08dec97,vin  fixed ip_freemoptions() SPR 9970. 
01k,19nov97,vin  changed extern declaration of _ipCfgFlags to int from UCHAR.
01j,13nov97,vin  provided an additional flag for sending large BCAST pkts.
01i,05oct97,vin  added fast multicasting.
01h,15jul97,spm  made IP checksum calculation configurable (SPR #7836)
01g,08mar97,vin  added mCastRouteFwdHook to access mcast routing code.
01f,24mar97,vin  bug fixed in ip_mloopback() ip hdr being shared, SPR8252
01e,13feb97,rjc  fixed bad parameter to TOS_SET	
01d,05feb97,rjc  changes for tos routing and fix for multicast bug.
01c,05dec96,vin  changed malloc(..) to MALLOC(..) to use only network buffers,
		 changed free(..) to FREE(..).
01b,22nov96,vin  added cluster support replaced m_get(..) with mBufClGet(..)
		 replaced m_gethdr with mHdrClGet(..)
01a,03mar96,vin  created from BSD4.4 stuff,integrated with 02n of ip_output.c
*/

#include "vxWorks.h"
#include "netLib.h"
#include "net/mbuf.h"
#include "errno.h"
#include "net/protosw.h"
#include "sys/socket.h"
#include "net/socketvar.h"

#include "net/if.h"
#include "net/route.h"

#include "netinet/in.h"
#include "netinet/in_pcb.h"
#include "netinet/in_systm.h"
#include "netinet/in_var.h"
#include "netinet/ip.h"
#include "netinet/ip_var.h"
#include "net/systm.h"

/* externs */

IMPORT int 	_ipCfgFlags; 		/* Calculate IP checksum? */

extern FUNCPTR _mCastRouteFwdHook;	/* WRS mcast forward command hook */
extern  looutput();

static struct mbuf *ip_insertoptions (struct mbuf *, struct mbuf *, int *);
static void ip_mloopback (struct ifnet *, struct mbuf *, struct sockaddr_in *);
static int  ip_setmoptions (int, struct inpcb *, struct mbuf *);

/*
 * 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(m0, opt, ro, flags, imo)
	struct mbuf *m0;
	struct mbuf *opt;
	struct route *ro;
	int flags;
	struct ip_moptions *imo;
{
	register struct ip *ip, *mhip;
	register struct ifnet *ifp;
	register struct mbuf *m = m0;
	register int hlen = sizeof (struct ip);
	int len, off, error = 0;
	struct route iproute;
	struct sockaddr_in *dst;
	struct in_ifaddr *ia;

#ifdef	DIAGNOSTIC
	if ((m->m_flags & M_PKTHDR) == 0)
		panic("ip_output no HDR");
#endif
	if (opt) {
		m = ip_insertoptions(m, opt, &len);
		hlen = len;
	}
	ip = mtod(m, struct ip *);
	/*
	 * Fill in IP header.
	 */
	if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
		ip->ip_v = IPVERSION;
		ip->ip_off &= IP_DF;
		ip->ip_id = htons(ip_id++);
		ip->ip_hl = hlen >> 2;
		ipstat.ips_localout++;
	} else {
		hlen = ip->ip_hl << 2;
	}
	/*
	 * Route packet.
	 */
	if (ro == 0) {
		ro = &iproute;
		bzero((caddr_t)ro, sizeof (*ro));
	}
	dst = (struct sockaddr_in *)&ro->ro_dst;
	/*
	 * If there is a cached route,
	 * check that it is to the same destination
	 * and is still up.  If not, free it and try again.
	 */
	if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
	   dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
		RTFREE(ro->ro_rt);
		ro->ro_rt = (struct rtentry *)0;
	}
	if (ro->ro_rt == 0) {
		dst->sin_family = AF_INET;
		dst->sin_len = sizeof(*dst);
		dst->sin_addr = ip->ip_dst;
		TOS_SET (dst, ip->ip_tos);
	}
	/*
	 * If routing to interface only,
	 * short circuit routing lookup.
	 */
#define ifatoia(ifa)	((struct in_ifaddr *)(ifa))
#define sintosa(sin)	((struct sockaddr *)(sin))
	if (flags & IP_ROUTETOIF ) {
		if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 &&
		    (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
			ipstat.ips_noroute++;
			error = ENETUNREACH;
			goto bad;
		}
		ifp = ia->ia_ifp;
		ip->ip_ttl = 1;
	} else if (! (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && imo &&
	              ((imo->imo_multicast_ifp != NULL)))) {
		if (ro->ro_rt == 0)
			rtalloc(ro);
		if (ro->ro_rt == 0) {
			ipstat.ips_noroute++;
			error = EHOSTUNREACH;
			goto bad;
		}
		ia = ifatoia(ro->ro_rt->rt_ifa);
		ifp = ro->ro_rt->rt_ifp;
		ro->ro_rt->rt_use++;
		if (ro->ro_rt->rt_flags & RTF_GATEWAY)
			dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
	}
	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
		struct in_multi *inm;
		extern struct ifnet loif;

		m->m_flags |= M_MCAST;
		/*
		 * IP destination address is multicast.  Make sure "dst"
		 * still points to the address in "ro".  (It may have been
		 * changed to point to a gateway address, above.)
		 */
		dst = (struct sockaddr_in *)&ro->ro_dst;

               if (imo && imo->imo_multicast_ifp != NULL) 
                   {

                   register struct in_ifaddr *ia;

                   for (ia = in_ifaddr; ia; ia = ia->ia_next)
                       if (ia->ia_ifp == ifp) 
                           {
		           dst->sin_addr.s_addr = IA_SIN(ia)->sin_addr.s_addr;
	                   break;
			   }

                   if (ro->ro_rt)
                       {
                       RTFREE(ro->ro_rt);
                       ro->ro_rt = (struct rtentry *)0;
                       }
                   }

		/*
		 * See if the caller provided any multicast options
		 */
		if (imo != NULL) {
			ip->ip_ttl = imo->imo_multicast_ttl;
			if (imo->imo_multicast_ifp != NULL)
				ifp = imo->imo_multicast_ifp;
		} else
			ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
		/*
		 * Confirm that the outgoing interface supports multicast.
		 */
		if ((ifp->if_flags & IFF_MULTICAST) == 0) {
			ipstat.ips_noroute++;
			error = ENETUNREACH;
			goto bad;
		}
		/*
		 * If source address not specified yet, use address
		 * of outgoing interface.
		 */
		if (ip->ip_src.s_addr == INADDR_ANY) {
			register struct in_ifaddr *ia;

			for (ia = in_ifaddr; ia; ia = ia->ia_next)
				if (ia->ia_ifp == ifp) {
					ip->ip_src = IA_SIN(ia)->sin_addr;
					break;
				}
		}

		IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm);
		if (inm != NULL &&
		   (imo == NULL || imo->imo_multicast_loop)) {
			/*
			 * If we belong to the destination multicast group
			 * on the outgoing interface, and the caller did not
			 * forbid loopback, loop back a copy.
			 */
			ip_mloopback(ifp, m, dst);
		}
		else {
			/*
			 * If we are acting as a multicast router, perform
			 * multicast forwarding as if the packet had just
			 * arrived on the interface to which we are about
			 * to send.  The multicast forwarding function
			 * recursively calls this function, using the
			 * IP_FORWARDING flag to prevent infinite recursion.
			 *
			 * Multicasts that are looped back by ip_mloopback(),
			 * above, will be forwarded by the ip_input() routine,
			 * if necessary.
			 */
                	if ((_mCastRouteFwdHook != NULL) &&
                            ((flags & IP_FORWARDING) == 0)) {
				if ((*_mCastRouteFwdHook)(m, ifp) != 0) {
					m_freem(m);
					goto done;
				}
			}
		}
		/*
		 * Multicasts with a time-to-live of zero may be looped-
		 * back, above, but must not be transmitted on a network.
		 * Also, multicasts addressed to the loopback interface
		 * are not sent -- the above call to ip_mloopback() will
		 * loop back a copy if this host actually belongs to the
		 * destination group on the loopback interface.
		 */
		if (ip->ip_ttl == 0 || ifp == &loif) {
			m_freem(m);
			goto done;
		}

		goto sendit;
	}
#ifndef notdef
	/*
	 * If source address not specified yet, use address
	 * of outgoing interface.
	 */
	if (ip->ip_src.s_addr == INADDR_ANY)
		ip->ip_src = IA_SIN(ia)->sin_addr;
#endif
	/*
	 * Look for broadcast address and
	 * and verify user is allowed to send
	 * such a packet.
	 */
	if (in_broadcast(dst->sin_addr, ifp)) {
		if ((ifp->if_flags & IFF_BROADCAST) == 0) {
			error = EADDRNOTAVAIL;
			goto bad;
		}
		if ((flags & IP_ALLOWBROADCAST) == 0) {
			error = EACCES;
			goto bad;
		}
		/* allow broadcast messages to be fragmented if flag set */
		if (((u_short)ip->ip_len > ifp->if_mtu) &&
                    !(_ipCfgFlags & IP_DO_LARGE_BCAST)) {
			error = EMSGSIZE;
			goto bad;
		}
		m->m_flags |= M_BCAST;
	} else
		m->m_flags &= ~M_BCAST;

sendit:
	/*
	 * If small enough for interface, can just send directly.
	 */
	if ((u_short)ip->ip_len <= ifp->if_mtu) {
		ip->ip_len = htons((u_short)ip->ip_len);
		ip->ip_off = htons((u_short)ip->ip_off);

		ip->ip_sum = 0;
                if (_ipCfgFlags & IP_DO_CHECKSUM_SND)
                    ip->ip_sum = in_cksum(m, hlen);

		error = (*ifp->if_output)(ifp, m,
				(struct sockaddr *)dst, ro->ro_rt);
		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 = EMSGSIZE;
		ipstat.ips_cantfrag++;
		goto bad;
	}
	len = (ifp->if_mtu - hlen) &~ 7;
	if (len < 8) {
		error = EMSGSIZE;
		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_short)ip->ip_len; off += len) {
		m= mHdrClGet(M_DONTWAIT, MT_HEADER, CL_SIZE_128, TRUE);
		if (m == 0) {
			error = ENOBUFS;
			ipstat.ips_odropped++;
			goto sendorfree;
		}
		m->m_flags = m0->m_flags;
		m->m_data += max_linkhdr;
		mhip = mtod(m, struct ip *);
		*mhip = *ip;
		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_short)ip->ip_len)
			len = (u_short)ip->ip_len - off;
		else
			mhip->ip_off |= IP_MF;
		mhip->ip_len = htons((u_short)(len + mhlen));
		m->m_next = m_copy(m0, off, len);
		if (m->m_next == 0) {
			(void) m_free(m);
			error = ENOBUFS;	/* ??? */
			ipstat.ips_odropped++;
			goto sendorfree;
		}
		m->m_pkthdr.len = mhlen + len;