File:  [DragonFly] / src / sys / netinet / if_ether.c
Revision 1.11: download - view: text, annotated - select for diffs
Fri Apr 9 22:34:10 2004 UTC (10 years, 7 months ago) by hsu
Branches: MAIN
CVS tags: HEAD
Push the lwkt_replymsg() up one level from netisr_service_loop() to
the message handler so we can explicitly reply or not reply as appropriate.

    1: /*
    2:  * Copyright (c) 1982, 1986, 1988, 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:  *	@(#)if_ether.c	8.1 (Berkeley) 6/10/93
   34:  * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $
   35:  * $DragonFly: src/sys/netinet/if_ether.c,v 1.11 2004/04/09 22:34:10 hsu Exp $
   36:  */
   37: 
   38: /*
   39:  * Ethernet address resolution protocol.
   40:  * TODO:
   41:  *	add "inuse/lock" bit (or ref. count) along with valid bit
   42:  */
   43: 
   44: #include "opt_inet.h"
   45: #include "opt_bdg.h"
   46: 
   47: #include <sys/param.h>
   48: #include <sys/kernel.h>
   49: #include <sys/queue.h>
   50: #include <sys/sysctl.h>
   51: #include <sys/systm.h>
   52: #include <sys/mbuf.h>
   53: #include <sys/malloc.h>
   54: #include <sys/socket.h>
   55: #include <sys/syslog.h>
   56: 
   57: #include <sys/thread2.h>
   58: #include <sys/msgport2.h>
   59: 
   60: #include <net/if.h>
   61: #include <net/if_dl.h>
   62: #include <net/if_types.h>
   63: #include <net/route.h>
   64: #include <net/netisr.h>
   65: #include <net/if_llc.h>
   66: #ifdef BRIDGE
   67: #include <net/ethernet.h>
   68: #include <net/bridge/bridge.h>
   69: #endif
   70: 
   71: #include <netinet/in.h>
   72: #include <netinet/in_var.h>
   73: #include <netinet/if_ether.h>
   74: 
   75: #include <net/if_arc.h>
   76: #include <net/iso88025.h>
   77: 
   78: #define SIN(s) ((struct sockaddr_in *)s)
   79: #define SDL(s) ((struct sockaddr_dl *)s)
   80: 
   81: SYSCTL_DECL(_net_link_ether);
   82: SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
   83: 
   84: /* timer values */
   85: static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
   86: static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
   87: static int arpt_down = 20;	/* once declared down, don't send for 20 sec */
   88: 
   89: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
   90: 	   &arpt_prune, 0, "");
   91: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 
   92: 	   &arpt_keep, 0, "");
   93: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
   94: 	   &arpt_down, 0, "");
   95: 
   96: #define	rt_expire rt_rmx.rmx_expire
   97: 
   98: struct llinfo_arp {
   99: 	LIST_ENTRY(llinfo_arp) la_le;
  100: 	struct	rtentry *la_rt;
  101: 	struct	mbuf *la_hold;	/* last packet until resolved/timeout */
  102: 	u_short	la_preempt;	/* #times we QUERIED before entry expiration */
  103: 	u_short	la_asked;	/* #times we QUERIED following expiration */
  104: #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
  105: };
  106: 
  107: static	LIST_HEAD(, llinfo_arp) llinfo_arp;
  108: 
  109: static int	arp_inuse, arp_allocated, arpinit_done;
  110: 
  111: static int	arp_maxtries = 5;
  112: static int	useloopback = 1; /* use loopback interface for local traffic */
  113: static int	arp_proxyall = 0;
  114: 
  115: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
  116: 	   &arp_maxtries, 0, "");
  117: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
  118: 	   &useloopback, 0, "");
  119: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
  120: 	   &arp_proxyall, 0, "");
  121: 
  122: static void	arp_rtrequest (int, struct rtentry *, struct rt_addrinfo *);
  123: static void	arprequest (struct ifnet *,
  124: 			struct in_addr *, struct in_addr *, u_char *);
  125: static void	arpintr(struct netmsg *);
  126: static void	arptfree (struct llinfo_arp *);
  127: static void	arptimer (void *);
  128: static struct llinfo_arp
  129: 		*arplookup (u_long, int, int);
  130: #ifdef INET
  131: static void	in_arpinput (struct mbuf *);
  132: #endif
  133: 
  134: u_char arcbroadcastaddr = 0;
  135: 
  136: #define IF_BCASTADDR(ifp)					\
  137: 	((ifp)->if_type == IFT_ARCNET ?				\
  138: 		&arcbroadcastaddr : etherbroadcastaddr)
  139: 
  140: /*
  141:  * Timeout routine.  Age arp_tab entries periodically.
  142:  */
  143: /* ARGSUSED */
  144: static void
  145: arptimer(ignored_arg)
  146: 	void *ignored_arg;
  147: {
  148: 	int s = splnet();
  149: 	struct llinfo_arp *la = LIST_FIRST(&llinfo_arp);
  150: 	struct llinfo_arp *ola;
  151: 
  152: 	timeout(arptimer, (caddr_t)0, arpt_prune * hz);
  153: 	while ((ola = la) != 0) {
  154: 		struct rtentry *rt = la->la_rt;
  155: 		la = LIST_NEXT(la, la_le);
  156: 		if (rt->rt_expire && rt->rt_expire <= time_second)
  157: 			arptfree(ola); /* timer has expired, clear */
  158: 	}
  159: 	splx(s);
  160: }
  161: 
  162: /*
  163:  * Parallel to llc_rtrequest.
  164:  */
  165: static void
  166: arp_rtrequest(req, rt, info)
  167: 	int req;
  168: 	struct rtentry *rt;
  169: 	struct rt_addrinfo *info;
  170: {
  171: 	struct sockaddr *gate = rt->rt_gateway;
  172: 	struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
  173: 	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
  174: 
  175: 	if (!arpinit_done) {
  176: 		arpinit_done = 1;
  177: 		timeout(arptimer, (caddr_t)0, hz);
  178: 	}
  179: 	if (rt->rt_flags & RTF_GATEWAY)
  180: 		return;
  181: 	switch (req) {
  182: 
  183: 	case RTM_ADD:
  184: 		/*
  185: 		 * XXX: If this is a manually added route to interface
  186: 		 * such as older version of routed or gated might provide,
  187: 		 * restore cloning bit.
  188: 		 */
  189: 		if ((rt->rt_flags & RTF_HOST) == 0 &&
  190: 		    SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
  191: 			rt->rt_flags |= RTF_CLONING;
  192: 		if (rt->rt_flags & RTF_CLONING) {
  193: 			/*
  194: 			 * Case 1: This route should come from a route to iface.
  195: 			 */
  196: 			rt_setgate(rt, rt_key(rt),
  197: 					(struct sockaddr *)&null_sdl);
  198: 			gate = rt->rt_gateway;
  199: 			SDL(gate)->sdl_type = rt->rt_ifp->if_type;
  200: 			SDL(gate)->sdl_index = rt->rt_ifp->if_index;
  201: 			rt->rt_expire = time_second;
  202: 			break;
  203: 		}
  204: 		/* Announce a new entry if requested. */
  205: 		if (rt->rt_flags & RTF_ANNOUNCE)
  206: 			arprequest(rt->rt_ifp,
  207: 			    &SIN(rt_key(rt))->sin_addr,
  208: 			    &SIN(rt_key(rt))->sin_addr,
  209: 			    (u_char *)LLADDR(SDL(gate)));
  210: 		/*FALLTHROUGH*/
  211: 	case RTM_RESOLVE:
  212: 		if (gate->sa_family != AF_LINK ||
  213: 		    gate->sa_len < sizeof(null_sdl)) {
  214: 			log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
  215: 			break;
  216: 		}
  217: 		SDL(gate)->sdl_type = rt->rt_ifp->if_type;
  218: 		SDL(gate)->sdl_index = rt->rt_ifp->if_index;
  219: 		if (la != 0)
  220: 			break; /* This happens on a route change */
  221: 		/*
  222: 		 * Case 2:  This route may come from cloning, or a manual route
  223: 		 * add with a LL address.
  224: 		 */
  225: 		R_Malloc(la, struct llinfo_arp *, sizeof(*la));
  226: 		rt->rt_llinfo = (caddr_t)la;
  227: 		if (la == 0) {
  228: 			log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
  229: 			break;
  230: 		}
  231: 		arp_inuse++, arp_allocated++;
  232: 		Bzero(la, sizeof(*la));
  233: 		la->la_rt = rt;
  234: 		rt->rt_flags |= RTF_LLINFO;
  235: 		LIST_INSERT_HEAD(&llinfo_arp, la, la_le);
  236: 
  237: #ifdef INET
  238: 		/*
  239: 		 * This keeps the multicast addresses from showing up
  240: 		 * in `arp -a' listings as unresolved.  It's not actually
  241: 		 * functional.  Then the same for broadcast.
  242: 		 */
  243: 		if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))
  244: 		&&  rt->rt_ifp->if_type != IFT_ARCNET) {
  245: 			ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
  246: 					       LLADDR(SDL(gate)));
  247: 			SDL(gate)->sdl_alen = 6;
  248: 			rt->rt_expire = 0;
  249: 		}
  250: 		if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
  251: 			memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp),
  252: 			       rt->rt_ifp->if_addrlen);
  253: 			SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen;
  254: 			rt->rt_expire = 0;
  255: 		}
  256: #endif
  257: 
  258: 		if (SIN(rt_key(rt))->sin_addr.s_addr ==
  259: 		    (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
  260: 		    /*
  261: 		     * This test used to be
  262: 		     *	if (loif.if_flags & IFF_UP)
  263: 		     * It allowed local traffic to be forced
  264: 		     * through the hardware by configuring the loopback down.
  265: 		     * However, it causes problems during network configuration
  266: 		     * for boards that can't receive packets they send.
  267: 		     * It is now necessary to clear "useloopback" and remove
  268: 		     * the route to force traffic out to the hardware.
  269: 		     */
  270: 			rt->rt_expire = 0;
  271: 			Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)),
  272: 			      SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen);
  273: 			if (useloopback)
  274: 				rt->rt_ifp = loif;
  275: 
  276: 		}
  277: 		break;
  278: 
  279: 	case RTM_DELETE:
  280: 		if (la == 0)
  281: 			break;
  282: 		arp_inuse--;
  283: 		LIST_REMOVE(la, la_le);
  284: 		rt->rt_llinfo = 0;
  285: 		rt->rt_flags &= ~RTF_LLINFO;
  286: 		if (la->la_hold)
  287: 			m_freem(la->la_hold);
  288: 		Free((caddr_t)la);
  289: 	}
  290: }
  291: 
  292: /*
  293:  * Broadcast an ARP request. Caller specifies:
  294:  *	- arp header source ip address
  295:  *	- arp header target ip address
  296:  *	- arp header source ethernet address
  297:  */
  298: static void
  299: arprequest(ifp, sip, tip, enaddr)
  300: 	struct ifnet *ifp;
  301: 	struct in_addr *sip, *tip;
  302: 	u_char *enaddr;
  303: {
  304: 	struct mbuf *m;
  305: 	struct ether_header *eh;
  306: 	struct arc_header *arh;
  307: 	struct arphdr *ah;
  308: 	struct sockaddr sa;
  309: 	static u_char	llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP,
  310: 				   LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 };
  311: 	u_short ar_hrd;
  312: 
  313: 	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
  314: 		return;
  315: 	m->m_pkthdr.rcvif = (struct ifnet *)0;
  316: 	switch (ifp->if_type) {
  317: 	case IFT_ARCNET:
  318: 		ar_hrd = htons(ARPHRD_ARCNET);
  319: 
  320: 		m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
  321: 		m->m_pkthdr.len = m->m_len;
  322: 		MH_ALIGN(m, m->m_len);
  323: 
  324: 		arh = (struct arc_header *)sa.sa_data;
  325: 		arh->arc_dhost = arcbroadcastaddr;
  326: 		arh->arc_type = ARCTYPE_ARP;
  327: 
  328: 		ah = mtod(m, struct arphdr *);
  329: 		break;
  330: 
  331: 	case IFT_ISO88025:
  332: 		ar_hrd = htons(ARPHRD_IEEE802);
  333: 
  334: 		m->m_len = sizeof(llcx) +
  335: 		    arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
  336: 		m->m_pkthdr.len = m->m_len;
  337: 		MH_ALIGN(m, m->m_len);
  338: 
  339: 		(void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx));
  340: 		(void)memcpy(sa.sa_data, etherbroadcastaddr, 6);
  341: 		(void)memcpy(sa.sa_data + 6, enaddr, 6);
  342: 		sa.sa_data[6] |= TR_RII;
  343: 		sa.sa_data[12] = TR_AC;
  344: 		sa.sa_data[13] = TR_LLC_FRAME;
  345: 
  346: 		ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx));
  347: 		break;
  348: 	case IFT_FDDI:
  349: 	case IFT_ETHER:
  350: 		/*
  351: 		 * This may not be correct for types not explicitly
  352: 		 * listed, but this is our best guess
  353: 		 */
  354: 	default:
  355: 		ar_hrd = htons(ARPHRD_ETHER);
  356: 
  357: 		m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
  358: 		m->m_pkthdr.len = m->m_len;
  359: 		MH_ALIGN(m, m->m_len);
  360: 
  361: 		eh = (struct ether_header *)sa.sa_data;
  362: 		/* if_output will not swap */
  363: 		eh->ether_type = htons(ETHERTYPE_ARP);
  364: 		(void)memcpy(eh->ether_dhost, etherbroadcastaddr,
  365: 		    sizeof(eh->ether_dhost));
  366: 
  367: 		ah = mtod(m, struct arphdr *);
  368: 		break;
  369: 	}
  370: 
  371: 	ah->ar_hrd = ar_hrd;
  372: 	ah->ar_pro = htons(ETHERTYPE_IP);
  373: 	ah->ar_hln = ifp->if_addrlen;		/* hardware address length */
  374: 	ah->ar_pln = sizeof(struct in_addr);	/* protocol address length */
  375: 	ah->ar_op = htons(ARPOP_REQUEST);
  376: 	(void)memcpy(ar_sha(ah), enaddr, ah->ar_hln);
  377: 	memset(ar_tha(ah), 0, ah->ar_hln);
  378: 	(void)memcpy(ar_spa(ah), sip, ah->ar_pln);
  379: 	(void)memcpy(ar_tpa(ah), tip, ah->ar_pln);
  380: 
  381: 	sa.sa_family = AF_UNSPEC;
  382: 	sa.sa_len = sizeof(sa);
  383: 	(*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
  384: }
  385: 
  386: /*
  387:  * Resolve an IP address into an ethernet address.  If success,
  388:  * desten is filled in.  If there is no entry in arptab,
  389:  * set one up and broadcast a request for the IP address.
  390:  * Hold onto this mbuf and resend it once the address
  391:  * is finally resolved.  A return value of 1 indicates
  392:  * that desten has been filled in and the packet should be sent
  393:  * normally; a 0 return indicates that the packet has been
  394:  * taken over here, either now or for later transmission.
  395:  */
  396: int
  397: arpresolve(ifp, rt, m, dst, desten, rt0)
  398: 	struct ifnet *ifp;
  399: 	struct rtentry *rt;
  400: 	struct mbuf *m;
  401: 	struct sockaddr *dst;
  402: 	u_char *desten;
  403: 	struct rtentry *rt0;
  404: {
  405: 	struct llinfo_arp *la = 0;
  406: 	struct sockaddr_dl *sdl;
  407: 
  408: 	if (m->m_flags & M_BCAST) {	/* broadcast */
  409: 		(void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen);
  410: 		return (1);
  411: 	}
  412: 	if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */
  413: 		ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
  414: 		return(1);
  415: 	}
  416: 	if (rt)
  417: 		la = (struct llinfo_arp *)rt->rt_llinfo;
  418: 	if (la == 0) {
  419: 		la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
  420: 		if (la)
  421: 			rt = la->la_rt;
  422: 	}
  423: 	if (la == 0 || rt == 0) {
  424: 		log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
  425: 			inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "",
  426: 				rt ? "rt" : "");
  427: 		m_freem(m);
  428: 		return (0);
  429: 	}
  430: 	sdl = SDL(rt->rt_gateway);
  431: 	/*
  432: 	 * Check the address family and length is valid, the address
  433: 	 * is resolved; otherwise, try to resolve.
  434: 	 */
  435: 	if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
  436: 	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
  437: 		/*
  438: 		 * If entry has an expiry time and it is approaching,
  439: 		 * see if we need to send an ARP request within this
  440: 		 * arpt_down interval.
  441: 		 */
  442: 		if ((rt->rt_expire != 0) &&
  443: 		    (time_second + (arp_maxtries - la->la_preempt) * arpt_down
  444: 		     > rt->rt_expire)) {
  445: 			arprequest(ifp,
  446: 				   &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
  447: 				   &SIN(dst)->sin_addr,
  448: 				   IF_LLADDR(ifp));
  449: 			la->la_preempt++;
  450: 		} 
  451: 
  452: 		bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
  453: 		return 1;
  454: 	}
  455: 	/*
  456: 	 * If ARP is disabled on this interface, stop.
  457: 	 * XXX
  458: 	 * Probably should not allocate empty llinfo struct if we are
  459: 	 * not going to be sending out an arp request.
  460: 	 */
  461: 	if (ifp->if_flags & IFF_NOARP) {
  462: 		m_freem(m);
  463: 		return (0);
  464: 	}
  465: 	/*
  466: 	 * There is an arptab entry, but no ethernet address
  467: 	 * response yet.  Replace the held mbuf with this
  468: 	 * latest one.
  469: 	 */
  470: 	if (la->la_hold)
  471: 		m_freem(la->la_hold);
  472: 	la->la_hold = m;
  473: 	if (rt->rt_expire) {
  474: 		rt->rt_flags &= ~RTF_REJECT;
  475: 		if (la->la_asked == 0 || rt->rt_expire != time_second) {
  476: 			rt->rt_expire = time_second;
  477: 			if (la->la_asked++ < arp_maxtries) {
  478: 				arprequest(ifp,
  479: 					   &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
  480: 					   &SIN(dst)->sin_addr,
  481: 					   IF_LLADDR(ifp));
  482: 			} else {
  483: 				rt->rt_flags |= RTF_REJECT;
  484: 				rt->rt_expire += arpt_down;
  485: 				la->la_preempt = la->la_asked = 0;
  486: 			}
  487: 
  488: 		}
  489: 	}
  490: 	return (0);
  491: }
  492: 
  493: /*
  494:  * Common length and type checks are done here,
  495:  * then the protocol-specific routine is called.
  496:  */
  497: static void
  498: arpintr(struct netmsg *msg)
  499: {
  500: 	struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet;
  501: 	struct arphdr *ar;
  502: 	u_short ar_hrd;
  503: 
  504: 	if (m->m_len < sizeof(struct arphdr) &&
  505: 	    ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) {
  506: 		log(LOG_ERR, "arp: runt packet -- m_pullup failed\n");
  507: 		return;
  508: 	}
  509: 	ar = mtod(m, struct arphdr *);
  510: 
  511: 	ar_hrd = ntohs(ar->ar_hrd);
  512: 	if (ar_hrd != ARPHRD_ETHER &&
  513: 	    ar_hrd != ARPHRD_IEEE802 &&
  514: 	    ar_hrd != ARPHRD_ARCNET) {
  515: 		log(LOG_ERR,
  516: 		    "arp: unknown hardware address format (0x%2D)\n",
  517: 		    (unsigned char *)&ar->ar_hrd, "");
  518: 		m_freem(m);
  519: 		return;
  520: 	}
  521: 
  522: 	if (m->m_pkthdr.len < arphdr_len(ar) &&
  523: 	    (m = m_pullup(m, arphdr_len(ar))) == NULL) {
  524: 		log(LOG_ERR, "arp: runt packet\n");
  525: 		m_freem(m);
  526: 		return;
  527: 	}
  528: 
  529: 	switch (ntohs(ar->ar_pro)) {
  530: #ifdef INET
  531: 		case ETHERTYPE_IP:
  532: 			in_arpinput(m);
  533: 			return;
  534: #endif
  535: 	}
  536: 	m_freem(m);
  537: 	lwkt_replymsg(&msg->nm_lmsg, 0);
  538: }
  539: 
  540: #ifdef INET
  541: /*
  542:  * ARP for Internet protocols on 10 Mb/s Ethernet.
  543:  * Algorithm is that given in RFC 826.
  544:  * In addition, a sanity check is performed on the sender
  545:  * protocol address, to catch impersonators.
  546:  * We no longer handle negotiations for use of trailer protocol:
  547:  * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
  548:  * along with IP replies if we wanted trailers sent to us,
  549:  * and also sent them in response to IP replies.
  550:  * This allowed either end to announce the desire to receive
  551:  * trailer packets.
  552:  * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
  553:  * but formerly didn't normally send requests.
  554:  */
  555: static int log_arp_wrong_iface = 1;
  556: 
  557: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW,
  558: 	&log_arp_wrong_iface, 0,
  559: 	"log arp packets arriving on the wrong interface");
  560: 
  561: static void
  562: in_arpinput(m)
  563: 	struct mbuf *m;
  564: {
  565: 	struct arphdr *ah;
  566: 	struct ifnet *ifp = m->m_pkthdr.rcvif;
  567: 	struct ether_header *eh;
  568: 	struct arc_header *arh;
  569: 	struct iso88025_header *th = (struct iso88025_header *)0;
  570: 	struct iso88025_sockaddr_dl_data *trld;
  571: 	struct llinfo_arp *la = 0;
  572: 	struct rtentry *rt;
  573: 	struct ifaddr *ifa;
  574: 	struct in_ifaddr *ia;
  575: 	struct sockaddr_dl *sdl;
  576: 	struct sockaddr sa;
  577: 	struct in_addr isaddr, itaddr, myaddr;
  578: 	int op, rif_len;
  579: 	int req_len;
  580: 
  581: 	req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr));
  582: 	if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) {
  583: 		log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n");
  584: 		return;
  585: 	}
  586: 
  587: 	ah = mtod(m, struct arphdr *);
  588: 	op = ntohs(ah->ar_op);
  589: 	(void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr));
  590: 	(void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr));
  591: #ifdef BRIDGE
  592: #define BRIDGE_TEST (do_bridge)
  593: #else
  594: #define BRIDGE_TEST (0) /* cc will optimise the test away */
  595: #endif
  596: 	/*
  597: 	 * For a bridge, we want to check the address irrespective
  598: 	 * of the receive interface. (This will change slightly
  599: 	 * when we have clusters of interfaces).
  600: 	 */
  601: 	LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash)
  602: 		if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) &&
  603: 		    itaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
  604: 			goto match;
  605: 	LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash)
  606: 		if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) &&
  607: 		    isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
  608: 			goto match;
  609: 	/*
  610: 	 * No match, use the first inet address on the receive interface
  611: 	 * as a dummy address for the rest of the function.
  612: 	 */
  613: 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
  614: 		if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) {
  615: 			ia = ifatoia(ifa);
  616: 			goto match;
  617: 		}
  618: 	/*
  619: 	 * If bridging, fall back to using any inet address.
  620: 	 * This is probably incorrect, the right way being try to match
  621: 	 * addresses for interfaces in the same cluster, so if we
  622: 	 * get here we should always drop the packet.
  623: 	 */
  624: 	if (!BRIDGE_TEST ||
  625: 	    (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) {
  626: 		m_freem(m);
  627: 		return;
  628: 	}
  629: match:
  630: 	myaddr = ia->ia_addr.sin_addr;
  631: 	if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) {
  632: 		m_freem(m);	/* it's from me, ignore it. */
  633: 		return;
  634: 	}
  635: 	if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) {
  636: 		log(LOG_ERR,
  637: 		    "arp: link address is broadcast for IP address %s!\n",
  638: 		    inet_ntoa(isaddr));
  639: 		m_freem(m);
  640: 		return;
  641: 	}
  642: 	if (isaddr.s_addr == myaddr.s_addr) {
  643: 		log(LOG_ERR,
  644: 		   "arp: %*D is using my IP address %s!\n",
  645: 		   ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
  646: 		   inet_ntoa(isaddr));
  647: 		itaddr = myaddr;
  648: 		goto reply;
  649: 	}
  650: 	la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
  651: 	if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
  652: 		/* the following is not an error when doing bridging */
  653: 		if (!BRIDGE_TEST && rt->rt_ifp != ifp) {
  654: 		    if (log_arp_wrong_iface)
  655: 			log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n",
  656: 			    inet_ntoa(isaddr),
  657: 			    rt->rt_ifp->if_xname,
  658: 			    ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
  659: 			    ifp->if_xname);
  660: 		    goto reply;
  661: 		}
  662: 		if (sdl->sdl_alen &&
  663: 		    bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) {
  664: 			if (rt->rt_expire)
  665: 			    log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n",
  666: 				inet_ntoa(isaddr),
  667: 				ifp->if_addrlen, (u_char *)LLADDR(sdl), ":",
  668: 				ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
  669: 				ifp->if_xname);
  670: 			else {
  671: 			    log(LOG_ERR,
  672: 				"arp: %*D attempts to modify permanent entry for %s on %s\n",
  673: 				ifp->if_addrlen, (u_char *)ar_sha(ah), ":",
  674: 				inet_ntoa(isaddr), ifp->if_xname);
  675: 			    goto reply;
  676: 			}
  677: 		}
  678: 		/*
  679: 		 * sanity check for the address length.
  680: 		 * XXX this does not work for protocols with variable address
  681: 		 * length. -is
  682: 		 */
  683: 		if (sdl->sdl_alen &&
  684: 		    sdl->sdl_alen != ah->ar_hln) {
  685: 			log(LOG_WARNING,
  686: 			    "arp from %*D: new addr len %d, was %d",
  687: 			    ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
  688: 			    ah->ar_hln, sdl->sdl_alen);
  689: 		}
  690: 		if (ifp->if_addrlen != ah->ar_hln) {
  691: 			log(LOG_WARNING,
  692: 			    "arp from %*D: addr len: new %d, i/f %d (ignored)",
  693: 			    ifp->if_addrlen, (u_char *) ar_sha(ah), ":",
  694: 			    ah->ar_hln, ifp->if_addrlen);
  695: 			goto reply;
  696: 		}
  697: 		(void)memcpy(LLADDR(sdl), ar_sha(ah),
  698: 		    sdl->sdl_alen = ah->ar_hln);
  699: 		/*
  700: 		 * If we receive an arp from a token-ring station over
  701: 		 * a token-ring nic then try to save the source
  702: 		 * routing info.
  703: 		 */
  704: 		if (ifp->if_type == IFT_ISO88025) {
  705: 			th = (struct iso88025_header *)m->m_pkthdr.header;
  706: 			trld = SDL_ISO88025(sdl);
  707: 			rif_len = TR_RCF_RIFLEN(th->rcf);
  708: 			if ((th->iso88025_shost[0] & TR_RII) &&
  709: 			    (rif_len > 2)) {
  710: 				trld->trld_rcf = th->rcf;
  711: 				trld->trld_rcf ^= htons(TR_RCF_DIR);
  712: 				memcpy(trld->trld_route, th->rd, rif_len - 2);
  713: 				trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK);
  714: 				/*
  715: 				 * Set up source routing information for
  716: 				 * reply packet (XXX)
  717: 				 */
  718: 				m->m_data -= rif_len;
  719: 				m->m_len  += rif_len;
  720: 				m->m_pkthdr.len += rif_len;
  721: 			} else {
  722: 				th->iso88025_shost[0] &= ~TR_RII;
  723: 				trld->trld_rcf = 0;
  724: 			}
  725: 			m->m_data -= 8;
  726: 			m->m_len  += 8;
  727: 			m->m_pkthdr.len += 8;
  728: 			th->rcf = trld->trld_rcf;
  729: 		}
  730: 		if (rt->rt_expire)
  731: 			rt->rt_expire = time_second + arpt_keep;
  732: 		rt->rt_flags &= ~RTF_REJECT;
  733: 		la->la_preempt = la->la_asked = 0;
  734: 		if (la->la_hold) {
  735: 			(*ifp->if_output)(ifp, la->la_hold,
  736: 				rt_key(rt), rt);
  737: 			la->la_hold = 0;
  738: 		}
  739: 	}
  740: reply:
  741: 	if (op != ARPOP_REQUEST) {
  742: 		m_freem(m);
  743: 		return;
  744: 	}
  745: 	if (itaddr.s_addr == myaddr.s_addr) {
  746: 		/* I am the target */
  747: 		(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
  748: 		(void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln);
  749: 	} else {
  750: 		la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
  751: 		if (la == NULL) {
  752: 			struct sockaddr_in sin;
  753: 
  754: 			if (!arp_proxyall) {
  755: 				m_freem(m);
  756: 				return;
  757: 			}
  758: 
  759: 			bzero(&sin, sizeof sin);
  760: 			sin.sin_family = AF_INET;
  761: 			sin.sin_len = sizeof sin;
  762: 			sin.sin_addr = itaddr;
  763: 
  764: 			rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
  765: 			if (!rt) {
  766: 				m_freem(m);
  767: 				return;
  768: 			}
  769: 			/*
  770: 			 * Don't send proxies for nodes on the same interface
  771: 			 * as this one came out of, or we'll get into a fight
  772: 			 * over who claims what Ether address.
  773: 			 */
  774: 			if (rt->rt_ifp == ifp) {
  775: 				rtfree(rt);
  776: 				m_freem(m);
  777: 				return;
  778: 			}
  779: 			(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
  780: 			(void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln);
  781: 			rtfree(rt);
  782: #ifdef DEBUG_PROXY
  783: 			printf("arp: proxying for %s\n",
  784: 			       inet_ntoa(itaddr));
  785: #endif
  786: 		} else {
  787: 			rt = la->la_rt;
  788: 			(void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln);
  789: 			sdl = SDL(rt->rt_gateway);
  790: 			(void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln);
  791: 		}
  792: 	}
  793: 
  794: 	(void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
  795: 	(void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
  796: 	ah->ar_op = htons(ARPOP_REPLY);
  797: 	ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */
  798: 	switch (ifp->if_type) {
  799: 	case IFT_ARCNET:
  800: 		arh = (struct arc_header *)sa.sa_data;
  801: 		arh->arc_dhost = *ar_tha(ah);
  802: 		arh->arc_type = ARCTYPE_ARP;
  803: 		break;
  804: 
  805: 	case IFT_ISO88025:
  806: 		/* Re-arrange the source/dest address */
  807: 		memcpy(th->iso88025_dhost, th->iso88025_shost,
  808: 		    sizeof(th->iso88025_dhost));
  809: 		memcpy(th->iso88025_shost, IF_LLADDR(ifp),
  810: 		    sizeof(th->iso88025_shost));
  811: 		/* Set the source routing bit if neccesary */
  812: 		if (th->iso88025_dhost[0] & TR_RII) {
  813: 			th->iso88025_dhost[0] &= ~TR_RII;
  814: 			if (TR_RCF_RIFLEN(th->rcf) > 2)
  815: 				th->iso88025_shost[0] |= TR_RII;
  816: 		}
  817: 		/* Copy the addresses, ac and fc into sa_data */
  818: 		memcpy(sa.sa_data, th->iso88025_dhost,
  819: 		    sizeof(th->iso88025_dhost) * 2);
  820: 		sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC;
  821: 		sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME;
  822: 		break;
  823: 	case IFT_ETHER:
  824: 	case IFT_FDDI:
  825: 	/*
  826: 	 * May not be correct for types not explictly
  827: 	 * listed, but it is our best guess.
  828: 	 */
  829: 	default:
  830: 		eh = (struct ether_header *)sa.sa_data;
  831: 		(void)memcpy(eh->ether_dhost, ar_tha(ah),
  832: 		    sizeof(eh->ether_dhost));
  833: 		eh->ether_type = htons(ETHERTYPE_ARP);
  834: 		break;
  835: 	}
  836: 	sa.sa_family = AF_UNSPEC;
  837: 	sa.sa_len = sizeof(sa);
  838: 	(*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0);
  839: 	return;
  840: }
  841: #endif
  842: 
  843: /*
  844:  * Free an arp entry.
  845:  */
  846: static void
  847: arptfree(la)
  848: 	struct llinfo_arp *la;
  849: {
  850: 	struct rtentry *rt = la->la_rt;
  851: 	struct sockaddr_dl *sdl;
  852: 	if (rt == 0)
  853: 		panic("arptfree");
  854: 	if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
  855: 	    sdl->sdl_family == AF_LINK) {
  856: 		sdl->sdl_alen = 0;
  857: 		la->la_preempt = la->la_asked = 0;
  858: 		rt->rt_flags &= ~RTF_REJECT;
  859: 		return;
  860: 	}
  861: 	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
  862: 			0, (struct rtentry **)0);
  863: }
  864: /*
  865:  * Lookup or enter a new address in arptab.
  866:  */
  867: static struct llinfo_arp *
  868: arplookup(addr, create, proxy)
  869: 	u_long addr;
  870: 	int create, proxy;
  871: {
  872: 	struct rtentry *rt;
  873: 	static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };
  874: 	const char *why = 0;
  875: 
  876: 	sin.sin_addr.s_addr = addr;
  877: 	sin.sin_other = proxy ? SIN_PROXY : 0;
  878: 	rt = rtalloc1((struct sockaddr *)&sin, create, 0UL);
  879: 	if (rt == 0)
  880: 		return (0);
  881: 	rt->rt_refcnt--;
  882: 
  883: 	if (rt->rt_flags & RTF_GATEWAY)
  884: 		why = "host is not on local network";
  885: 	else if ((rt->rt_flags & RTF_LLINFO) == 0)
  886: 		why = "could not allocate llinfo";
  887: 	else if (rt->rt_gateway->sa_family != AF_LINK)
  888: 		why = "gateway route is not ours";
  889: 
  890: 	if (why) {
  891: 		if (create) {
  892: 			log(LOG_DEBUG, "arplookup %s failed: %s\n",
  893: 			    inet_ntoa(sin.sin_addr), why);
  894: 		}
  895: 
  896: 		/* if there are no references to this route, purge it */
  897: 		if (rt->rt_refcnt <= 0 &&
  898: 		    (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) {
  899: 			    rtrequest(RTM_DELETE,
  900: 				(struct sockaddr *)rt_key(rt), rt->rt_gateway,
  901: 				rt_mask(rt), rt->rt_flags, 0);
  902: 		}
  903: 		return (0);
  904: 	}
  905: 	return ((struct llinfo_arp *)rt->rt_llinfo);
  906: }
  907: 
  908: void
  909: arp_ifinit(ifp, ifa)
  910: 	struct ifnet *ifp;
  911: 	struct ifaddr *ifa;
  912: {
  913: 	if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
  914: 		arprequest(ifp, &IA_SIN(ifa)->sin_addr,
  915: 				&IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp));
  916: 	ifa->ifa_rtrequest = arp_rtrequest;
  917: 	ifa->ifa_flags |= RTF_CLONING;
  918: }
  919: 
  920: static void
  921: arp_init(void)
  922: {
  923: 	LIST_INIT(&llinfo_arp);
  924: 	netisr_register(NETISR_ARP, cpu0_portfn, arpintr);
  925: }
  926: 
  927: SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);