if_ether.c

嵌入式操作系统ECOS的网络开发包

//==========================================================================
//
//      sys/netinet/if_ether.c
//
//     
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD or other sources,
// and are covered by the appropriate copyright disclaimers included herein.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    gthomas
// Contributors: gthomas
// Date:         2000-01-10
// Purpose:      
// Description:  
//              
//
//####DESCRIPTIONEND####
//
//==========================================================================


/*	$OpenBSD: if_ether.c,v 1.19 1999/11/10 18:48:47 chris Exp $	*/
/*	$NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1988, 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.
 *
 *	@(#)if_ether.c	8.1 (Berkeley) 6/10/93
 */

/*
 * Ethernet address resolution protocol.
 * TODO:
 *	add "inuse/lock" bit (or ref. count) along with valid bit
 */

#include <sys/param.h>
#ifndef __ECOS
#include <sys/systm.h>
#endif
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#ifndef __ECOS
#include <sys/syslog.h>
#include <sys/proc.h>
#endif

#ifdef INET

#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>

#define SIN(s) ((struct sockaddr_in *)s)
#define SDL(s) ((struct sockaddr_dl *)s)
#define SRP(s) ((struct sockaddr_inarp *)s)

/*
 * ARP trailer negotiation.  Trailer protocol is not IP specific,
 * but ARP request/response use IP addresses.
 */
#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL

/* timer values */
int	arpt_prune = (5*60*1);	/* walk list every 5 minutes */
int	arpt_keep = (20*60);	/* once resolved, good for 20 more minutes */
int	arpt_down = 20;		/* once declared down, don't send for 20 secs */
#define	rt_expire rt_rmx.rmx_expire

static	void arprequest
	    __P((struct arpcom *, u_int32_t *, u_int32_t *, u_int8_t *));
static	void arptfree __P((struct llinfo_arp *));
static	void arptimer __P((void *));
static	struct llinfo_arp *arplookup __P((u_int32_t, int, int));
static	void in_arpinput __P((struct mbuf *));

extern	struct ifnet loif;
LIST_HEAD(, llinfo_arp) llinfo_arp;
struct	ifqueue arpintrq = {0, 0, 0, 50};
int	arp_inuse, arp_allocated, arp_intimer;
int	arp_maxtries = 5;
int	useloopback = 1;	/* use loopback interface for local traffic */
int	arpinit_done = 0;

/* revarp state */
static struct in_addr myip, srv_ip;
static int myip_initialized = 0;
static int revarp_in_progress = 0;
struct ifnet *myip_ifp = NULL;

static void arptimer __P((void *));
static void arprequest __P((struct arpcom *, u_int32_t *, u_int32_t *,
			    u_int8_t *));
static void in_arpinput __P((struct mbuf *));
static void arptfree __P((struct llinfo_arp *));
static struct llinfo_arp *arplookup __P((u_int32_t, int, int ));
#ifdef DDB
#include <vm/vm.h>

static void db_print_sa __P((struct sockaddr *));
static void db_print_ifa __P((struct ifaddr *));
static void db_print_llinfo __P((caddr_t));
static int db_show_radix_node __P((struct radix_node *, void *));
#endif

/*
 * Timeout routine.  Age arp_tab entries periodically.
 */
/* ARGSUSED */
static void
arptimer(arg)
	void *arg;
{
	int s;
	register struct llinfo_arp *la, *nla;

	s = splsoftnet();
	timeout(arptimer, NULL, arpt_prune * hz);
	for (la = llinfo_arp.lh_first; la != 0; la = nla) {
		register struct rtentry *rt = la->la_rt;

		nla = la->la_list.le_next;
		if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
			arptfree(la); /* timer has expired; clear */
	}
	splx(s);
}

/*
 * Parallel to llc_rtrequest.
 */
void
arp_rtrequest(req, rt, sa)
	int req;
	register struct rtentry *rt;
	struct sockaddr *sa;
{
	register struct sockaddr *gate = rt->rt_gateway;
	register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};

	if (!arpinit_done) {
		arpinit_done = 1;
		/*
		 * We generate expiration times from time.tv_sec
		 * so avoid accidently creating permanent routes.
		 */
		if (time.tv_sec == 0) {
			time.tv_sec++;
		}
		timeout(arptimer, (caddr_t)0, hz);
	}
	if (rt->rt_flags & RTF_GATEWAY)
		return;
	switch (req) {

	case RTM_ADD:
		/*
		 * XXX: If this is a manually added route to interface
		 * such as older version of routed or gated might provide,
		 * restore cloning bit.
		 */
		if ((rt->rt_flags & RTF_HOST) == 0 &&
		    SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
			rt->rt_flags |= RTF_CLONING;
		if (rt->rt_flags & RTF_CLONING) {
			/*
			 * Case 1: This route should come from a route to iface.
			 */
			rt_setgate(rt, rt_key(rt),
					(struct sockaddr *)&null_sdl);
			gate = rt->rt_gateway;
			SDL(gate)->sdl_type = rt->rt_ifp->if_type;
			SDL(gate)->sdl_index = rt->rt_ifp->if_index;
			/*
			 * Give this route an expiration time, even though
			 * it's a "permanent" route, so that routes cloned
			 * from it do not need their expiration time set.
			 */
			rt->rt_expire = time.tv_sec;
			break;
		}
		/* Announce a new entry if requested. */
		if (rt->rt_flags & RTF_ANNOUNCE)
			arprequest((struct arpcom *)rt->rt_ifp,
			    &SIN(rt_key(rt))->sin_addr.s_addr,
			    &SIN(rt_key(rt))->sin_addr.s_addr,
			    (u_char *)LLADDR(SDL(gate)));
		/*FALLTHROUGH*/
	case RTM_RESOLVE:
		if (gate->sa_family != AF_LINK ||
		    gate->sa_len < sizeof(null_sdl)) {
#ifdef __ECOS
#else
			log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
#endif
			break;
		}
		SDL(gate)->sdl_type = rt->rt_ifp->if_type;
		SDL(gate)->sdl_index = rt->rt_ifp->if_index;
		if (la != 0)
			break; /* This happens on a route change */
		/*
		 * Case 2:  This route may come from cloning, or a manual route
		 * add with a LL address.
		 */
		R_Malloc(la, struct llinfo_arp *, sizeof(*la));
		rt->rt_llinfo = (caddr_t)la;
		if (la == 0) {
#ifdef __ECOS
#else
			log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
#endif
			break;
		}
		arp_inuse++, arp_allocated++;
		Bzero(la, sizeof(*la));
		la->la_rt = rt;
		rt->rt_flags |= RTF_LLINFO;
		LIST_INSERT_HEAD(&llinfo_arp, la, la_list);
		if (SIN(rt_key(rt))->sin_addr.s_addr ==
		    (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
			/*
			 * This test used to be
			 *	if (loif.if_flags & IFF_UP)
			 * It allowed local traffic to be forced through
			 * the hardware by configuring the loopback down.
			 * However, it causes problems during network
			 * configuration for boards that can't receive
			 * packets they send.  It is now necessary to clear
			 * "useloopback" and remove the route to force
			 * traffic out to the hardware.
			 */
			rt->rt_expire = 0;
			Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
			    LLADDR(SDL(gate)),
			    SDL(gate)->sdl_alen = ETHER_ADDR_LEN);
			if (useloopback)
				rt->rt_ifp = &loif;
		}
		break;

	case RTM_DELETE:
		if (la == 0)
			break;
		arp_inuse--;
		LIST_REMOVE(la, la_list);
		rt->rt_llinfo = 0;
		rt->rt_flags &= ~RTF_LLINFO;
		if (la->la_hold)
			m_freem(la->la_hold);
		Free((caddr_t)la);
	}
}

/*
 * Broadcast an ARP request. Caller specifies:
 *	- arp header source ip address
 *	- arp header target ip address
 *	- arp header source ethernet address
 */
static void
arprequest(ac, sip, tip, enaddr)
	register struct arpcom *ac;
	register u_int32_t *sip, *tip;
	register u_int8_t *enaddr;
{
	register struct mbuf *m;
	register struct ether_header *eh;
	register struct ether_arp *ea;
	struct sockaddr sa;

	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
		return;
	m->m_len = sizeof(*ea);
	m->m_pkthdr.len = sizeof(*ea);
	MH_ALIGN(m, sizeof(*ea));
	ea = mtod(m, struct ether_arp *);
	eh = (struct ether_header *)sa.sa_data;
	bzero((caddr_t)ea, sizeof (*ea));
	bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
	    sizeof(eh->ether_dhost));
	eh->ether_type = htons(ETHERTYPE_ARP);	/* if_output will not swap */
	ea->arp_hrd = htons(ARPHRD_ETHER);
	ea->arp_pro = htons(ETHERTYPE_IP);
	ea->arp_hln = sizeof(ea->arp_sha);	/* hardware address length */
	ea->arp_pln = sizeof(ea->arp_spa);	/* protocol address length */
	ea->arp_op = htons(ARPOP_REQUEST);
	bcopy((caddr_t)enaddr, (caddr_t)eh->ether_shost,
	      sizeof(eh->ether_shost));
	bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
	bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
	bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa));
	sa.sa_family = AF_UNSPEC;
	sa.sa_len = sizeof(sa);
	(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
}

/*
 * Resolve an IP address into an ethernet address.  If success,
 * desten is filled in.  If there is no entry in arptab,
 * set one up and broadcast a request for the IP address.
 * Hold onto this mbuf and resend it once the address
 * is finally resolved.  A return value of 1 indicates
 * that desten has been filled in and the packet should be sent
 * normally; a 0 return indicates that the packet has been
 * taken over here, either now or for later transmission.
 */
int
arpresolve(ac, rt, m, dst, desten)
	register struct arpcom *ac;
	register struct rtentry *rt;
	struct mbuf *m;
	register struct sockaddr *dst;
	register u_char *desten;
{
	register struct llinfo_arp *la;
	struct sockaddr_dl *sdl;

	if (m->m_flags & M_BCAST) {	/* broadcast */
		bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,
		    sizeof(etherbroadcastaddr));
		return (1);
	}
	if (m->m_flags & M_MCAST) {	/* multicast */
		ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
		return (1);
	}
	if (rt)
		la = (struct llinfo_arp *)rt->rt_llinfo;
	else {
		if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL)
			rt = la->la_rt;
	}
	if (la == 0 || rt == 0) {
#ifdef __ECOS
#else
		log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n");
#endif
		m_freem(m);
		return (0);
	}
	sdl = SDL(rt->rt_gateway);
	/*
	 * Check the address family and length is valid, the address
	 * is resolved; otherwise, try to resolve.
	 */
	if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&
	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
		bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
		return 1;
	}
	if (((struct ifnet *)ac)->if_flags & IFF_NOARP)
		return 0;

	/*
	 * There is an arptab entry, but no ethernet address
	 * response yet.  Replace the held mbuf with this
	 * latest one.
	 */
	if (la->la_hold)
		m_freem(la->la_hold);
	la->la_hold = m;
	/*
	 * Re-send the ARP request when appropriate.
	 */
#ifdef	DIAGNOSTIC
	if (rt->rt_expire == 0) {
		/* This should never happen. (Should it? -gwr) */
		printf("arpresolve: unresolved and rt_expire == 0\n");
		/* Set expiration time to now (expired). */
		rt->rt_expire = time.tv_sec;
	}
#endif
	if (rt->rt_expire) {
		rt->rt_flags &= ~RTF_REJECT;
		if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {
			rt->rt_expire = time.tv_sec;
			if (la->la_asked++ < arp_maxtries)
				arprequest(ac,
				    &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr),
				    &(SIN(dst)->sin_addr.s_addr),
				    ac->ac_enaddr);
			else {
				rt->rt_flags |= RTF_REJECT;
				rt->rt_expire += arpt_down;
				la->la_asked = 0;
			}
		}
	}
	return (0);
}

/*
 * Common length and type checks are done here,
 * then the protocol-specific routine is called.
 */
void
arpintr()
{
	register struct mbuf *m;
	register struct arphdr *ar;
	int s;

	while (arpintrq.ifq_head) {
		s = splimp();
		IF_DEQUEUE(&arpintrq, m);
		splx(s);
		if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
			panic("arpintr");
		if (m->m_len >= sizeof(struct arphdr) &&
		    (ar = mtod(m, struct arphdr *)) &&
		    ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
		    m->m_len >=
		      sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
			switch (ntohs(ar->ar_pro)) {

			case ETHERTYPE_IP:
			case ETHERTYPE_IPTRAILERS:
				in_arpinput(m);
				continue;
			}
		m_freem(m);
	}
}

/*
 * ARP for Internet protocols on Ethernet.
 * Algorithm is that given in RFC 826.
 * In addition, a sanity check is performed on the sender
 * protocol address, to catch impersonators.
 * We no longer handle negotiations for use of trailer protocol:
 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
 * along with IP replies if we wanted trailers sent to us,
 * and also sent them in response to IP replies.
 * This allowed either end to announce the desire to receive
 * trailer packets.
 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
 * but formerly didn't normally send requests.
 */
static void
in_arpinput(m)
	struct mbuf *m;
{
	register struct ether_arp *ea;
	register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
	struct ether_header *eh;
	register struct llinfo_arp *la = 0;
	register struct rtentry *rt;