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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /*
23: * Copyright (c) 1982, 1986, 1988, 1993
24: * The Regents of the University of California. All rights reserved.
25: *
26: * Redistribution and use in source and binary forms, with or without
27: * modification, are permitted provided that the following conditions
28: * are met:
29: * 1. Redistributions of source code must retain the above copyright
30: * notice, this list of conditions and the following disclaimer.
31: * 2. Redistributions in binary form must reproduce the above copyright
32: * notice, this list of conditions and the following disclaimer in the
33: * documentation and/or other materials provided with the distribution.
34: * 3. All advertising materials mentioning features or use of this software
35: * must display the following acknowledgement:
36: * This product includes software developed by the University of
37: * California, Berkeley and its contributors.
38: * 4. Neither the name of the University nor the names of its contributors
39: * may be used to endorse or promote products derived from this software
40: * without specific prior written permission.
41: *
42: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
43: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
44: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
45: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
46: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
47: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
48: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
49: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
50: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
51: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52: * SUCH DAMAGE.
53: *
54: * @(#)if_ether.c 8.1 (Berkeley) 6/10/93
55: */
56:
57: /*
58: * Ethernet address resolution protocol.
59: * TODO:
60: * add "inuse/lock" bit (or ref. count) along with valid bit
61: */
62:
63: #if NOTFB31
64: #include "opt_inet.h"
65: #include "opt_bdg.h"
66: #endif
67:
68: #include <sys/param.h>
69: #include <sys/kernel.h>
70:
71: #include <sys/sysctl.h>
72:
73: #include <sys/systm.h>
74: #include <sys/mbuf.h>
75: #include <sys/malloc.h>
76: #include <sys/socket.h>
77: #include <sys/syslog.h>
78:
79: #include <net/if.h>
80: #include <net/if_dl.h>
81: #include <net/route.h>
82: #include <net/netisr.h>
83:
84: #include <netinet/in.h>
85: #include <netinet/in_var.h>
86: #include <netinet/if_ether.h>
87:
88: #define SIN(s) ((struct sockaddr_in *)s)
89: #define SDL(s) ((struct sockaddr_dl *)s)
90:
91: SYSCTL_DECL(_net_link_ether);
92: SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
93:
94: /* timer values */
95: static int arpt_prune = (5*60*1); /* walk list every 5 minutes */
96: static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
97: static int arpt_down = 20; /* once declared down, don't send for 20 sec */
98:
99: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW,
100: &arpt_prune, 0, "");
101: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
102: &arpt_keep, 0, "");
103: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW,
104: &arpt_down, 0, "");
105:
106: #define rt_expire rt_rmx.rmx_expire
107:
108: struct llinfo_arp {
109: LIST_ENTRY(llinfo_arp) la_le;
110: struct rtentry *la_rt;
111: struct mbuf *la_hold; /* last packet until resolved/timeout */
112: long la_asked; /* last time we QUERIED for this addr */
113: #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */
114: };
115:
116: static LIST_HEAD(, llinfo_arp) llinfo_arp;
117:
118: struct ifqueue arpintrq = {0, 0, 0, 50};
119: static int arp_inuse, arp_allocated;
120:
121: static int arp_maxtries = 5;
122: static int useloopback = 1; /* use loopback interface for local traffic */
123: static int arp_proxyall = 0;
124: static int arp_init_called = 0;
125:
126: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW,
127: &arp_maxtries, 0, "");
128: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW,
129: &useloopback, 0, "");
130: SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW,
131: &arp_proxyall, 0, "");
132:
133: void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *));
134: static void arprequest __P((struct arpcom *,
135: struct in_addr *, struct in_addr *, u_char *));
136: void arpintr __P((void));
137: static void arptfree __P((struct llinfo_arp *));
138: static void arptimer __P((void *));
139: static struct llinfo_arp
140: *arplookup __P((u_long, int, int));
141: #if INET
142: static void in_arpinput __P((struct mbuf *));
143: #endif
144:
145: /*
146: * Timeout routine. Age arp_tab entries periodically.
147: */
148: /* ARGSUSED */
149: static void
150: arptimer(ignored_arg)
151: void *ignored_arg;
152: {
153: int s = splnet();
154: register struct llinfo_arp *la = llinfo_arp.lh_first;
155: struct llinfo_arp *ola;
156:
157: timeout(arptimer, (caddr_t)0, arpt_prune * hz);
158: while ((ola = la) != 0) {
159: register struct rtentry *rt = la->la_rt;
160: la = la->la_le.le_next;
161: if (rt->rt_expire && rt->rt_expire <= time_second)
162: arptfree(ola); /* timer has expired, clear */
163: }
164: splx(s);
165: }
166:
167: /*
168: * Parallel to llc_rtrequest.
169: */
170: void
171: arp_rtrequest(req, rt, sa)
172: int req;
173: register struct rtentry *rt;
174: struct sockaddr *sa;
175: {
176: register struct sockaddr *gate = rt->rt_gateway;
177: register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
178: static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
179: static int arpinit_done;
180:
181: if (!arpinit_done) {
182: arpinit_done = 1;
183: LIST_INIT(&llinfo_arp);
184: timeout(arptimer, (caddr_t)0, hz);
185: }
186: if (rt->rt_flags & RTF_GATEWAY)
187: return;
188: switch (req) {
189:
190: case RTM_ADD:
191: /*
192: * XXX: If this is a manually added route to interface
193: * such as older version of routed or gated might provide,
194: * restore cloning bit.
195: */
196: if ((rt->rt_flags & RTF_HOST) == 0 &&
197: SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
198: rt->rt_flags |= RTF_CLONING;
199: if (rt->rt_flags & RTF_CLONING) {
200: /*
201: * Case 1: This route should come from a route to iface.
202: */
203: rt_setgate(rt, rt_key(rt),
204: (struct sockaddr *)&null_sdl);
205: gate = rt->rt_gateway;
206: SDL(gate)->sdl_type = rt->rt_ifp->if_type;
207: SDL(gate)->sdl_index = rt->rt_ifp->if_index;
208: rt->rt_expire = time_second;
209: break;
210: }
211: /* Announce a new entry if requested. */
212: if (rt->rt_flags & RTF_ANNOUNCE)
213: arprequest((struct arpcom *)rt->rt_ifp,
214: &SIN(rt_key(rt))->sin_addr,
215: &SIN(rt_key(rt))->sin_addr,
216: (u_char *)LLADDR(SDL(gate)));
217: /*FALLTHROUGH*/
218: case RTM_RESOLVE:
219: if (gate->sa_family != AF_LINK ||
220: gate->sa_len < sizeof(null_sdl)) {
221: log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n");
222: break;
223: }
224: SDL(gate)->sdl_type = rt->rt_ifp->if_type;
225: SDL(gate)->sdl_index = rt->rt_ifp->if_index;
226: if (la != 0)
227: break; /* This happens on a route change */
228: /*
229: * Case 2: This route may come from cloning, or a manual route
230: * add with a LL address.
231: */
232: R_Malloc(la, struct llinfo_arp *, sizeof(*la));
233: rt->rt_llinfo = (caddr_t)la;
234: if (la == 0) {
235: log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
236: break;
237: }
238: arp_inuse++, arp_allocated++;
239: Bzero(la, sizeof(*la));
240: la->la_rt = rt;
241: rt->rt_flags |= RTF_LLINFO;
242: LIST_INSERT_HEAD(&llinfo_arp, la, la_le);
243:
244: #if INET
245: /*
246: * This keeps the multicast addresses from showing up
247: * in `arp -a' listings as unresolved. It's not actually
248: * functional. Then the same for broadcast.
249: */
250: if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) {
251: ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr,
252: LLADDR(SDL(gate)));
253: SDL(gate)->sdl_alen = 6;
254: rt->rt_expire = 0;
255: }
256: if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) {
257: memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6);
258: SDL(gate)->sdl_alen = 6;
259: rt->rt_expire = 0;
260: }
261: #endif
262:
263: if (SIN(rt_key(rt))->sin_addr.s_addr ==
264: (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
265: /*
266: * This test used to be
267: * if (loif.if_flags & IFF_UP)
268: * It allowed local traffic to be forced
269: * through the hardware by configuring the loopback down.
270: * However, it causes problems during network configuration
271: * for boards that can't receive packets they send.
272: * It is now necessary to clear "useloopback" and remove
273: * the route to force traffic out to the hardware.
274: */
275: rt->rt_expire = 0;
276: Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
277: LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6);
278: if (useloopback)
279: rt->rt_ifp = loif;
280:
281: }
282: break;
283:
284: case RTM_DELETE:
285: if (la == 0)
286: break;
287: arp_inuse--;
288: LIST_REMOVE(la, la_le);
289: rt->rt_llinfo = 0;
290: rt->rt_flags &= ~RTF_LLINFO;
291: if (la->la_hold)
292: m_freem(la->la_hold);
293: Free((caddr_t)la);
294: }
295: }
296:
297:
298:
299:
300: /*
301: * Broadcast an ARP packet, asking who has addr on interface ac.
302: */
303: void
304: arpwhohas(ac, addr)
305: register struct arpcom *ac;
306: register struct in_addr *addr;
307: { struct ifnet *ifp = (struct ifnet *)ac;
308: struct ifaddr *ifa = TAILQ_FIRST(&ifp->if_addrhead);
309:
310: while (ifa)
311: { if (ifa->ifa_addr->sa_family == AF_INET)
312: { arprequest(ac, &SIN(ifa->ifa_addr)->sin_addr, addr, ac->ac_enaddr);
313: return;
314: }
315: ifa = TAILQ_NEXT(ifa, ifa_link);
316: }
317: return; /* XXX */
318: }
319:
320:
321:
322: /*
323: * Broadcast an ARP request. Caller specifies:
324: * - arp header source ip address
325: * - arp header target ip address
326: * - arp header source ethernet address
327: */
328: static void
329: arprequest(ac, sip, tip, enaddr)
330: register struct arpcom *ac;
331: register struct in_addr *sip, *tip;
332: register u_char *enaddr;
333: {
334: register struct mbuf *m;
335: register struct ether_header *eh;
336: register struct ether_arp *ea;
337: struct sockaddr sa;
338:
339: if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
340: return;
341: m->m_len = sizeof(*ea);
342: m->m_pkthdr.len = sizeof(*ea);
343: MH_ALIGN(m, sizeof(*ea));
344: ea = mtod(m, struct ether_arp *);
345: eh = (struct ether_header *)sa.sa_data;
346: bzero((caddr_t)ea, sizeof (*ea));
347: (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost));
348: eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */
349: ea->arp_hrd = htons(ARPHRD_ETHER);
350: ea->arp_pro = htons(ETHERTYPE_IP);
351: ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */
352: ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */
353: ea->arp_op = htons(ARPOP_REQUEST);
354: (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha));
355: (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa));
356: (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa));
357: sa.sa_family = AF_UNSPEC;
358: sa.sa_len = sizeof(sa);
359: dlil_output((u_long) ac, m, 0, &sa, 0);
360: }
361:
362: /*
363: * Resolve an IP address into an ethernet address. If success,
364: * desten is filled in. If there is no entry in arptab,
365: * set one up and broadcast a request for the IP address.
366: * Hold onto this mbuf and resend it once the address
367: * is finally resolved. A return value of 1 indicates
368: * that desten has been filled in and the packet should be sent
369: * normally; a 0 return indicates that the packet has been
370: * taken over here, either now or for later transmission.
371: */
372: int
373: arpresolve(ac, rt, m, dst, desten, rt0)
374: register struct arpcom *ac;
375: register struct rtentry *rt;
376: struct mbuf *m;
377: register struct sockaddr *dst;
378: register u_char *desten;
379: struct rtentry *rt0;
380: {
381: register struct llinfo_arp *la = 0;
382: struct sockaddr_dl *sdl;
383:
384: if (m->m_flags & M_BCAST) { /* broadcast */
385: (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr));
386: return (1);
387: }
388: if (m->m_flags & M_MCAST) { /* multicast */
389: ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
390: return(1);
391: }
392: if (rt)
393: la = (struct llinfo_arp *)rt->rt_llinfo;
394: if (la == 0) {
395: la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
396: if (la)
397: rt = la->la_rt;
398: }
399: if (la == 0 || rt == 0) {
400: log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n",
401: inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "",
402: rt ? "rt" : "");
403: m_freem(m);
404: return (0);
405: }
406: sdl = SDL(rt->rt_gateway);
407: /*
408: * Check the address family and length is valid, the address
409: * is resolved; otherwise, try to resolve.
410: */
411: if ((rt->rt_expire == 0 || rt->rt_expire > time_second) &&
412: sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
413: bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
414: return 1;
415: }
416: /*
417: * There is an arptab entry, but no ethernet address
418: * response yet. Replace the held mbuf with this
419: * latest one.
420: */
421: if (la->la_hold)
422: m_freem(la->la_hold);
423: la->la_hold = m;
424: if (rt->rt_expire) {
425: rt->rt_flags &= ~RTF_REJECT;
426: if (la->la_asked == 0 || rt->rt_expire != time_second) {
427: rt->rt_expire = time_second;
428: if (la->la_asked++ < arp_maxtries)
429: arprequest(ac,
430: &SIN(rt->rt_ifa->ifa_addr)->sin_addr,
431: &SIN(dst)->sin_addr, ac->ac_enaddr);
432: else {
433: rt->rt_flags |= RTF_REJECT;
434: rt->rt_expire += arpt_down;
435: la->la_asked = 0;
436: }
437:
438: }
439: }
440: return (0);
441: }
442:
443: /*
444: * Common length and type checks are done here,
445: * then the protocol-specific routine is called.
446: */
447: void
448: arpintr()
449: {
450: register struct mbuf *m;
451: register struct arphdr *ar;
452: int s;
453:
454: while (arpintrq.ifq_head) {
455: s = splimp();
456: IF_DEQUEUE(&arpintrq, m);
457: splx(s);
458: if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
459: panic("arpintr");
460: if (m->m_len >= sizeof(struct arphdr) &&
461: (ar = mtod(m, struct arphdr *)) &&
462: ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
463: m->m_len >=
464: sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
465:
466: switch (ntohs(ar->ar_pro)) {
467:
468: #if INET
469: case ETHERTYPE_IP:
470: in_arpinput(m);
471: continue;
472: #endif
473: }
474: m_freem(m);
475: }
476: }
477:
478: NETISR_SET(NETISR_ARP, arpintr);
479:
480:
481: #if INET
482: /*
483: * ARP for Internet protocols on 10 Mb/s Ethernet.
484: * Algorithm is that given in RFC 826.
485: * In addition, a sanity check is performed on the sender
486: * protocol address, to catch impersonators.
487: * We no longer handle negotiations for use of trailer protocol:
488: * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
489: * along with IP replies if we wanted trailers sent to us,
490: * and also sent them in response to IP replies.
491: * This allowed either end to announce the desire to receive
492: * trailer packets.
493: * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
494: * but formerly didn't normally send requests.
495: */
496: static void
497: in_arpinput(m)
498: struct mbuf *m;
499: {
500: register struct ether_arp *ea;
501: register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
502: struct ether_header *eh;
503: register struct llinfo_arp *la = 0;
504: register struct rtentry *rt;
505: struct in_ifaddr *ia, *maybe_ia = 0;
506: struct sockaddr_dl *sdl;
507: struct sockaddr sa;
508: struct in_addr isaddr, itaddr, myaddr;
509: int op;
510: unsigned char buf[18];
511:
512: ea = mtod(m, struct ether_arp *);
513: op = ntohs(ea->arp_op);
514: (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr));
515: (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr));
516: for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next)
517: #if BRIDGE
518: /*
519: * For a bridge, we want to check the address irrespective
520: * of the receive interface. (This will change slightly
521: * when we have clusters of interfaces).
522: */
523: {
524: #else
525: if (ia->ia_ifp == &ac->ac_if) {
526: #endif
527: maybe_ia = ia;
528: if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) ||
529: (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr))
530: break;
531: }
532: if (maybe_ia == 0) {
533: m_freem(m);
534: return;
535: }
536: myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
537:
538: #if 0
539: /*
540: * In order to support BlueBox networking, we need to allow
541: * "self-addressed" stamped envelopes
542: */
543: if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
544: sizeof (ea->arp_sha))) {
545: m_freem(m); /* it's from me, ignore it. */
546: return;
547: }
548: #endif
549: if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
550: sizeof (ea->arp_sha))) {
551: log(LOG_ERR,
552: "arp: ether address is broadcast for IP address %s!\n",
553: inet_ntoa(isaddr));
554: m_freem(m);
555: return;
556: }
557: if (isaddr.s_addr == myaddr.s_addr) {
558: log(LOG_ERR,
559: "duplicate IP address %s sent from ethernet address %s\n",
560: inet_ntoa(isaddr), ether_sprintf(buf, ea->arp_sha));
561: itaddr = myaddr;
562: goto reply;
563: }
564: la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
565: if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
566: #ifndef BRIDGE /* the following is not an error when doing bridging */
567: if (rt->rt_ifp != &ac->ac_if) {
568: log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n",
569: inet_ntoa(isaddr),
570: rt->rt_ifp->if_name, rt->rt_ifp->if_unit,
571: ea->arp_sha, ":",
572: ac->ac_if.if_name, ac->ac_if.if_unit);
573: goto reply;
574: }
575: #endif
576: if (sdl->sdl_alen &&
577: bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
578: if (rt->rt_expire)
579: log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n",
580: inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":",
581: ea->arp_sha, ":",
582: ac->ac_if.if_name, ac->ac_if.if_unit);
583: else {
584: log(LOG_ERR,
585: "arp: %6D attempts to modify permanent entry for %s on %s%d",
586: ea->arp_sha, ":", inet_ntoa(isaddr),
587: ac->ac_if.if_name, ac->ac_if.if_unit);
588: goto reply;
589: }
590: (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha));
591: sdl->sdl_alen = sizeof(ea->arp_sha);
592: if (rt->rt_expire)
593: rt->rt_expire = time_second + arpt_keep;
594: rt->rt_flags &= ~RTF_REJECT;
595: la->la_asked = 0;
596: if (la->la_hold) {
597: dlil_output((u_long) ac, la->la_hold, rt,
598: rt_key(rt), 0);
599: la->la_hold = 0;
600: }
601: }
602: reply:
603: if (op != ARPOP_REQUEST) {
604: m_freem(m);
605: return;
606: }
607: if (itaddr.s_addr == myaddr.s_addr) {
608: /* I am the target */
609: (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
610: (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha));
611: } else {
612: la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
613: if (la == NULL) {
614: struct sockaddr_in sin;
615:
616: if (!arp_proxyall) {
617: m_freem(m);
618: return;
619: }
620:
621: bzero(&sin, sizeof sin);
622: sin.sin_family = AF_INET;
623: sin.sin_len = sizeof sin;
624: sin.sin_addr = itaddr;
625:
626: rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
627: if (!rt) {
628: m_freem(m);
629: return;
630: }
631: /*
632: * Don't send proxies for nodes on the same interface
633: * as this one came out of, or we'll get into a fight
634: * over who claims what Ether address.
635: */
636: if (rt->rt_ifp == &ac->ac_if) {
637: rtfree(rt);
638: m_freem(m);
639: return;
640: }
641: (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
642: (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha));
643: rtfree(rt);
644: #if DEBUG_PROXY
645: printf("arp: proxying for %s\n",
646: inet_ntoa(itaddr));
647: #endif
648: } else {
649: rt = la->la_rt;
650: (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha));
651: sdl = SDL(rt->rt_gateway);
652: (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha));
653: }
654: }
655:
656: (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa));
657: (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa));
658: ea->arp_op = htons(ARPOP_REPLY);
659: ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */
660: eh = (struct ether_header *)sa.sa_data;
661: (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost));
662: eh->ether_type = htons(ETHERTYPE_ARP);
663: sa.sa_family = AF_UNSPEC;
664: sa.sa_len = sizeof(sa);
665: dlil_output((u_long) ac, m, 0, &sa, 0);
666: return;
667: }
668: #endif
669:
670: /*
671: * Free an arp entry.
672: */
673: static void
674: arptfree(la)
675: register struct llinfo_arp *la;
676: {
677: register struct rtentry *rt = la->la_rt;
678: register struct sockaddr_dl *sdl;
679: if (rt == 0)
680: panic("arptfree");
681: if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
682: sdl->sdl_family == AF_LINK) {
683: sdl->sdl_alen = 0;
684: la->la_asked = 0;
685: rt->rt_flags &= ~RTF_REJECT;
686: return;
687: }
688: rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
689: 0, (struct rtentry **)0);
690: }
691: /*
692: * Lookup or enter a new address in arptab.
693: */
694: static struct llinfo_arp *
695: arplookup(addr, create, proxy)
696: u_long addr;
697: int create, proxy;
698: {
699: register struct rtentry *rt;
700: static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };
701: const char *why = 0;
702:
703: sin.sin_addr.s_addr = addr;
704: sin.sin_other = proxy ? SIN_PROXY : 0;
705: rt = rtalloc1((struct sockaddr *)&sin, create, 0UL);
706: if (rt == 0)
707: return (0);
708: rt->rt_refcnt--;
709:
710: if (rt->rt_flags & RTF_GATEWAY)
711: why = "host is not on local network";
712: else if ((rt->rt_flags & RTF_LLINFO) == 0)
713: why = "could not allocate llinfo";
714: else if (rt->rt_gateway->sa_family != AF_LINK)
715: why = "gateway route is not ours";
716:
717: if (why && create) {
718: log(LOG_DEBUG, "arplookup %s failed: %s\n",
719: inet_ntoa(sin.sin_addr), why);
720: return 0;
721: } else if (why) {
722: return 0;
723: }
724: return ((struct llinfo_arp *)rt->rt_llinfo);
725: }
726:
727: void
728: arp_ifinit(ac, ifa)
729: struct arpcom *ac;
730: struct ifaddr *ifa;
731: {
732: if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY)
733: arprequest(ac, &IA_SIN(ifa)->sin_addr,
734: &IA_SIN(ifa)->sin_addr, ac->ac_enaddr);
735: ifa->ifa_rtrequest = arp_rtrequest;
736: ifa->ifa_flags |= RTF_CLONING;
737: }
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.