if_llatbl.c revision 196019 
1/*
2 * Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
3 * Copyright (c) 2004-2008 Qing Li. All rights reserved.
4 * Copyright (c) 2008 Kip Macy. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/net/if_llatbl.c 196019 2009-08-01 19:26:27Z rwatson $");
29
30#include "opt_inet.h"
31#include "opt_inet6.h"
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/malloc.h>
36#include <sys/mbuf.h>
37#include <sys/syslog.h>
38#include <sys/sysctl.h>
39#include <sys/socket.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/mutex.h>
43#include <sys/rwlock.h>
44
45#include <vm/uma.h>
46
47#include <netinet/in.h>
48#include <net/if_llatbl.h>
49#include <net/if.h>
50#include <net/if_dl.h>
51#include <net/if_var.h>
52#include <net/route.h>
53#include <net/vnet.h>
54#include <netinet/if_ether.h>
55#include <netinet6/in6_var.h>
56#include <netinet6/nd6.h>
57
58MALLOC_DEFINE(M_LLTABLE, "lltable", "link level address tables");
59
60static	SLIST_HEAD(, lltable) lltables = SLIST_HEAD_INITIALIZER(lltables);
61
62extern void arprequest(struct ifnet *, struct in_addr *, struct in_addr *,
63	u_char *);
64
65/*
66 * Dump arp state for a specific address family.
67 */
68int
69lltable_sysctl_dumparp(int af, struct sysctl_req *wr)
70{
71	struct lltable *llt;
72	int error = 0;
73
74	IFNET_RLOCK();
75	SLIST_FOREACH(llt, &lltables, llt_link) {
76		if (llt->llt_af == af) {
77			error = llt->llt_dump(llt, wr);
78			if (error != 0)
79				goto done;
80		}
81	}
82done:
83	IFNET_RUNLOCK();
84	return (error);
85}
86
87/*
88 * Deletes an address from the address table.
89 * This function is called by the timer functions
90 * such as arptimer() and nd6_llinfo_timer(), and
91 * the caller does the locking.
92 */
93void
94llentry_free(struct llentry *lle)
95{
96
97	LLE_WLOCK_ASSERT(lle);
98	LIST_REMOVE(lle, lle_next);
99
100	if (lle->la_hold != NULL)
101		m_freem(lle->la_hold);
102
103	LLE_FREE_LOCKED(lle);
104}
105
106/*
107 * Update an llentry for address dst (equivalent to rtalloc for new-arp)
108 * Caller must pass in a valid struct llentry *
109 *
110 * if found the llentry * is returned referenced and unlocked
111 */
112int
113llentry_update(struct llentry **llep, struct lltable *lt,
114    struct sockaddr *dst, struct ifnet *ifp)
115{
116	struct llentry *la;
117
118	IF_AFDATA_RLOCK(ifp);
119	la = lla_lookup(lt, LLE_EXCLUSIVE,
120	    (struct sockaddr *)dst);
121	IF_AFDATA_RUNLOCK(ifp);
122	if ((la == NULL) &&
123	    (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) {
124		IF_AFDATA_WLOCK(ifp);
125		la = lla_lookup(lt,
126		    (LLE_CREATE | LLE_EXCLUSIVE),
127		    (struct sockaddr *)dst);
128		IF_AFDATA_WUNLOCK(ifp);
129	}
130	if (la != NULL && (*llep != la)) {
131		if (*llep != NULL)
132			LLE_FREE(*llep);
133		LLE_ADDREF(la);
134		LLE_WUNLOCK(la);
135		*llep = la;
136	} else if (la != NULL)
137		LLE_WUNLOCK(la);
138
139	if (la == NULL)
140		return (ENOENT);
141
142	return (0);
143}
144
145/*
146 * Free all entries from given table and free itself.
147 * Since lltables collects from all of the intefaces,
148 * the caller of this function must acquire IFNET_WLOCK().
149 */
150void
151lltable_free(struct lltable *llt)
152{
153	struct llentry *lle, *next;
154	int i;
155
156	KASSERT(llt != NULL, ("%s: llt is NULL", __func__));
157
158	IFNET_WLOCK();
159	SLIST_REMOVE(&lltables, llt, lltable, llt_link);
160	IFNET_WUNLOCK();
161
162	for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
163		LIST_FOREACH_SAFE(lle, &llt->lle_head[i], lle_next, next) {
164
165			callout_drain(&lle->la_timer);
166			LLE_WLOCK(lle);
167			llentry_free(lle);
168		}
169	}
170
171	free(llt, M_LLTABLE);
172}
173
174void
175lltable_drain(int af)
176{
177	struct lltable	*llt;
178	struct llentry	*lle;
179	register int i;
180
181	IFNET_RLOCK();
182	SLIST_FOREACH(llt, &lltables, llt_link) {
183		if (llt->llt_af != af)
184			continue;
185
186		for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
187			LIST_FOREACH(lle, &llt->lle_head[i], lle_next) {
188				if (lle->la_hold) {
189					m_freem(lle->la_hold);
190					lle->la_hold = NULL;
191				}
192			}
193		}
194	}
195	IFNET_RUNLOCK();
196}
197
198void
199lltable_prefix_free(int af, struct sockaddr *prefix, struct sockaddr *mask)
200{
201	struct lltable *llt;
202
203	IFNET_RLOCK();
204	SLIST_FOREACH(llt, &lltables, llt_link) {
205		if (llt->llt_af != af)
206			continue;
207
208		llt->llt_prefix_free(llt, prefix, mask);
209	}
210	IFNET_RUNLOCK();
211}
212
213
214
215/*
216 * Create a new lltable.
217 */
218struct lltable *
219lltable_init(struct ifnet *ifp, int af)
220{
221	struct lltable *llt;
222	register int i;
223
224	llt = malloc(sizeof(struct lltable), M_LLTABLE, M_WAITOK);
225	if (llt == NULL)
226		return (NULL);
227
228	llt->llt_af = af;
229	llt->llt_ifp = ifp;
230	for (i = 0; i < LLTBL_HASHTBL_SIZE; i++)
231		LIST_INIT(&llt->lle_head[i]);
232
233	IFNET_WLOCK();
234	SLIST_INSERT_HEAD(&lltables, llt, llt_link);
235	IFNET_WUNLOCK();
236
237	return (llt);
238}
239
240/*
241 * Called in route_output when adding/deleting a route to an interface.
242 */
243int
244lla_rt_output(struct rt_msghdr *rtm, struct rt_addrinfo *info)
245{
246	struct sockaddr_dl *dl =
247	    (struct sockaddr_dl *)info->rti_info[RTAX_GATEWAY];
248	struct sockaddr *dst = (struct sockaddr *)info->rti_info[RTAX_DST];
249	struct ifnet *ifp;
250	struct lltable *llt;
251	struct llentry *lle;
252	u_int laflags = 0, flags = 0;
253	int error = 0;
254
255	if (dl == NULL || dl->sdl_family != AF_LINK) {
256		log(LOG_INFO, "%s: invalid dl\n", __func__);
257		return EINVAL;
258	}
259	ifp = ifnet_byindex(dl->sdl_index);
260	if (ifp == NULL) {
261		log(LOG_INFO, "%s: invalid ifp (sdl_index %d)\n",
262		    __func__, dl->sdl_index);
263		return EINVAL;
264	}
265
266	switch (rtm->rtm_type) {
267	case RTM_ADD:
268		if (rtm->rtm_flags & RTF_ANNOUNCE) {
269			flags |= LLE_PUB;
270#ifdef INET
271			if (dst->sa_family == AF_INET &&
272			    ((struct sockaddr_inarp *)dst)->sin_other != 0) {
273				struct rtentry *rt = rtalloc1(dst, 0, 0);
274				if (rt == NULL || !(rt->rt_flags & RTF_HOST)) {
275					log(LOG_INFO, "%s: RTM_ADD publish "
276					    "(proxy only) is invalid\n",
277					    __func__);
278					if (rt)
279						RTFREE_LOCKED(rt);
280					return EINVAL;
281				}
282				RTFREE_LOCKED(rt);
283
284				flags |= LLE_PROXY;
285			}
286#endif
287		}
288		flags |= LLE_CREATE;
289		break;
290
291	case RTM_DELETE:
292		flags |= LLE_DELETE;
293		break;
294
295	case RTM_CHANGE:
296		break;
297
298	default:
299		return EINVAL; /* XXX not implemented yet */
300	}
301
302	/* XXX linked list may be too expensive */
303	IFNET_RLOCK();
304	SLIST_FOREACH(llt, &lltables, llt_link) {
305		if (llt->llt_af == dst->sa_family &&
306		    llt->llt_ifp == ifp)
307			break;
308	}
309	IFNET_RUNLOCK();
310	KASSERT(llt != NULL, ("Yep, ugly hacks are bad\n"));
311
312	if (flags && LLE_CREATE)
313		flags |= LLE_EXCLUSIVE;
314
315	IF_AFDATA_LOCK(ifp);
316	lle = lla_lookup(llt, flags, dst);
317	IF_AFDATA_UNLOCK(ifp);
318	if (LLE_IS_VALID(lle)) {
319		if (flags & LLE_CREATE) {
320			/*
321			 * If we delay the delete, then a subsequent
322			 * "arp add" should look up this entry, reset the
323			 * LLE_DELETED flag, and reset the expiration timer
324			 */
325			bcopy(LLADDR(dl), &lle->ll_addr, ifp->if_addrlen);
326			lle->la_flags |= LLE_VALID;
327			lle->la_flags &= ~LLE_DELETED;
328#ifdef INET6
329			/*
330			 * ND6
331			 */
332			if (dst->sa_family == AF_INET6)
333				lle->ln_state = ND6_LLINFO_REACHABLE;
334#endif
335			/*
336			 * NB: arp and ndp always set (RTF_STATIC | RTF_HOST)
337			 */
338
339			if (rtm->rtm_rmx.rmx_expire == 0) {
340				lle->la_flags |= LLE_STATIC;
341				lle->la_expire = 0;
342			} else
343				lle->la_expire = rtm->rtm_rmx.rmx_expire;
344			laflags = lle->la_flags;
345			LLE_WUNLOCK(lle);
346#ifdef INET
347			/*  gratuitous ARP */
348			if ((laflags & LLE_PUB) && dst->sa_family == AF_INET) {
349				arprequest(ifp,
350				    &((struct sockaddr_in *)dst)->sin_addr,
351				    &((struct sockaddr_in *)dst)->sin_addr,
352				    ((laflags & LLE_PROXY) ?
353					(u_char *)IF_LLADDR(ifp) :
354					(u_char *)LLADDR(dl)));
355			}
356#endif
357		} else {
358			if (flags & LLE_EXCLUSIVE)
359				LLE_WUNLOCK(lle);
360			else
361				LLE_RUNLOCK(lle);
362		}
363	} else if ((lle == NULL) && (flags & LLE_DELETE))
364		error = EINVAL;
365
366
367	return (error);
368}
369