77dfcdc445
several critical bugs, including race conditions and lock order issues: Replace the single rwlock, ifnet_lock, with two locks, an rwlock and an sxlock. Either can be held to stablize the lists and indexes, but both are required to write. This allows the list to be held stable in both network interrupt contexts and sleepable user threads across sleeping memory allocations or device driver interactions. As before, writes to the interface list must occur from sleepable contexts. Reviewed by: bz, julian MFC after: 3 days
369 lines
8.5 KiB
C
369 lines
8.5 KiB
C
/*
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* Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
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* Copyright (c) 2004-2008 Qing Li. All rights reserved.
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* Copyright (c) 2008 Kip Macy. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/syslog.h>
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#include <sys/sysctl.h>
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#include <sys/socket.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/rwlock.h>
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#include <vm/uma.h>
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#include <netinet/in.h>
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#include <net/if_llatbl.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/if_var.h>
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#include <net/route.h>
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#include <net/vnet.h>
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#include <netinet/if_ether.h>
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#include <netinet6/in6_var.h>
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#include <netinet6/nd6.h>
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MALLOC_DEFINE(M_LLTABLE, "lltable", "link level address tables");
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static SLIST_HEAD(, lltable) lltables = SLIST_HEAD_INITIALIZER(lltables);
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extern void arprequest(struct ifnet *, struct in_addr *, struct in_addr *,
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u_char *);
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/*
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* Dump arp state for a specific address family.
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*/
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int
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lltable_sysctl_dumparp(int af, struct sysctl_req *wr)
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{
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struct lltable *llt;
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int error = 0;
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IFNET_RLOCK();
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SLIST_FOREACH(llt, &lltables, llt_link) {
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if (llt->llt_af == af) {
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error = llt->llt_dump(llt, wr);
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if (error != 0)
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goto done;
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}
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}
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done:
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IFNET_RUNLOCK();
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return (error);
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}
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/*
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* Deletes an address from the address table.
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* This function is called by the timer functions
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* such as arptimer() and nd6_llinfo_timer(), and
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* the caller does the locking.
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*/
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void
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llentry_free(struct llentry *lle)
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{
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LLE_WLOCK_ASSERT(lle);
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LIST_REMOVE(lle, lle_next);
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if (lle->la_hold != NULL)
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m_freem(lle->la_hold);
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LLE_FREE_LOCKED(lle);
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}
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/*
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* Update an llentry for address dst (equivalent to rtalloc for new-arp)
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* Caller must pass in a valid struct llentry *
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*
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* if found the llentry * is returned referenced and unlocked
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*/
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int
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llentry_update(struct llentry **llep, struct lltable *lt,
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struct sockaddr *dst, struct ifnet *ifp)
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{
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struct llentry *la;
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IF_AFDATA_RLOCK(ifp);
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la = lla_lookup(lt, LLE_EXCLUSIVE,
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(struct sockaddr *)dst);
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IF_AFDATA_RUNLOCK(ifp);
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if ((la == NULL) &&
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(ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) {
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IF_AFDATA_WLOCK(ifp);
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la = lla_lookup(lt,
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(LLE_CREATE | LLE_EXCLUSIVE),
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(struct sockaddr *)dst);
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IF_AFDATA_WUNLOCK(ifp);
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}
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if (la != NULL && (*llep != la)) {
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if (*llep != NULL)
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LLE_FREE(*llep);
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LLE_ADDREF(la);
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LLE_WUNLOCK(la);
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*llep = la;
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} else if (la != NULL)
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LLE_WUNLOCK(la);
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if (la == NULL)
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return (ENOENT);
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return (0);
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}
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/*
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* Free all entries from given table and free itself.
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* Since lltables collects from all of the intefaces,
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* the caller of this function must acquire IFNET_WLOCK().
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*/
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void
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lltable_free(struct lltable *llt)
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{
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struct llentry *lle, *next;
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int i;
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KASSERT(llt != NULL, ("%s: llt is NULL", __func__));
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IFNET_WLOCK();
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SLIST_REMOVE(&lltables, llt, lltable, llt_link);
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IFNET_WUNLOCK();
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for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
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LIST_FOREACH_SAFE(lle, &llt->lle_head[i], lle_next, next) {
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callout_drain(&lle->la_timer);
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LLE_WLOCK(lle);
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llentry_free(lle);
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}
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}
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free(llt, M_LLTABLE);
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}
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void
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lltable_drain(int af)
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{
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struct lltable *llt;
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struct llentry *lle;
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register int i;
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IFNET_RLOCK();
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SLIST_FOREACH(llt, &lltables, llt_link) {
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if (llt->llt_af != af)
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continue;
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for (i=0; i < LLTBL_HASHTBL_SIZE; i++) {
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LIST_FOREACH(lle, &llt->lle_head[i], lle_next) {
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if (lle->la_hold) {
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m_freem(lle->la_hold);
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lle->la_hold = NULL;
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}
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}
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}
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}
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IFNET_RUNLOCK();
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}
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void
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lltable_prefix_free(int af, struct sockaddr *prefix, struct sockaddr *mask)
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{
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struct lltable *llt;
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IFNET_RLOCK_NOSLEEP();
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SLIST_FOREACH(llt, &lltables, llt_link) {
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if (llt->llt_af != af)
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continue;
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llt->llt_prefix_free(llt, prefix, mask);
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}
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IFNET_RUNLOCK_NOSLEEP();
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}
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/*
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* Create a new lltable.
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*/
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struct lltable *
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lltable_init(struct ifnet *ifp, int af)
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{
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struct lltable *llt;
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register int i;
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llt = malloc(sizeof(struct lltable), M_LLTABLE, M_WAITOK);
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if (llt == NULL)
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return (NULL);
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llt->llt_af = af;
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llt->llt_ifp = ifp;
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for (i = 0; i < LLTBL_HASHTBL_SIZE; i++)
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LIST_INIT(&llt->lle_head[i]);
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IFNET_WLOCK();
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SLIST_INSERT_HEAD(&lltables, llt, llt_link);
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IFNET_WUNLOCK();
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return (llt);
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}
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/*
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* Called in route_output when adding/deleting a route to an interface.
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*/
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int
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lla_rt_output(struct rt_msghdr *rtm, struct rt_addrinfo *info)
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{
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struct sockaddr_dl *dl =
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(struct sockaddr_dl *)info->rti_info[RTAX_GATEWAY];
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struct sockaddr *dst = (struct sockaddr *)info->rti_info[RTAX_DST];
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struct ifnet *ifp;
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struct lltable *llt;
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struct llentry *lle;
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u_int laflags = 0, flags = 0;
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int error = 0;
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if (dl == NULL || dl->sdl_family != AF_LINK) {
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log(LOG_INFO, "%s: invalid dl\n", __func__);
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return EINVAL;
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}
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ifp = ifnet_byindex(dl->sdl_index);
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if (ifp == NULL) {
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log(LOG_INFO, "%s: invalid ifp (sdl_index %d)\n",
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__func__, dl->sdl_index);
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return EINVAL;
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}
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switch (rtm->rtm_type) {
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case RTM_ADD:
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if (rtm->rtm_flags & RTF_ANNOUNCE) {
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flags |= LLE_PUB;
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#ifdef INET
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if (dst->sa_family == AF_INET &&
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((struct sockaddr_inarp *)dst)->sin_other != 0) {
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struct rtentry *rt = rtalloc1(dst, 0, 0);
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if (rt == NULL || !(rt->rt_flags & RTF_HOST)) {
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log(LOG_INFO, "%s: RTM_ADD publish "
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"(proxy only) is invalid\n",
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__func__);
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if (rt)
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RTFREE_LOCKED(rt);
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return EINVAL;
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}
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RTFREE_LOCKED(rt);
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flags |= LLE_PROXY;
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}
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#endif
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}
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flags |= LLE_CREATE;
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break;
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case RTM_DELETE:
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flags |= LLE_DELETE;
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break;
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case RTM_CHANGE:
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break;
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default:
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return EINVAL; /* XXX not implemented yet */
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}
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/* XXX linked list may be too expensive */
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IFNET_RLOCK_NOSLEEP();
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SLIST_FOREACH(llt, &lltables, llt_link) {
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if (llt->llt_af == dst->sa_family &&
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llt->llt_ifp == ifp)
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break;
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}
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IFNET_RUNLOCK_NOSLEEP();
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KASSERT(llt != NULL, ("Yep, ugly hacks are bad\n"));
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if (flags && LLE_CREATE)
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flags |= LLE_EXCLUSIVE;
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IF_AFDATA_LOCK(ifp);
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lle = lla_lookup(llt, flags, dst);
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IF_AFDATA_UNLOCK(ifp);
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if (LLE_IS_VALID(lle)) {
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if (flags & LLE_CREATE) {
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/*
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* If we delay the delete, then a subsequent
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* "arp add" should look up this entry, reset the
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* LLE_DELETED flag, and reset the expiration timer
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*/
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bcopy(LLADDR(dl), &lle->ll_addr, ifp->if_addrlen);
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lle->la_flags |= LLE_VALID;
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lle->la_flags &= ~LLE_DELETED;
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#ifdef INET6
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/*
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* ND6
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*/
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if (dst->sa_family == AF_INET6)
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lle->ln_state = ND6_LLINFO_REACHABLE;
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#endif
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/*
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* NB: arp and ndp always set (RTF_STATIC | RTF_HOST)
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*/
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if (rtm->rtm_rmx.rmx_expire == 0) {
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lle->la_flags |= LLE_STATIC;
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lle->la_expire = 0;
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} else
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lle->la_expire = rtm->rtm_rmx.rmx_expire;
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laflags = lle->la_flags;
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LLE_WUNLOCK(lle);
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#ifdef INET
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/* gratuitous ARP */
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if ((laflags & LLE_PUB) && dst->sa_family == AF_INET) {
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arprequest(ifp,
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&((struct sockaddr_in *)dst)->sin_addr,
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&((struct sockaddr_in *)dst)->sin_addr,
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((laflags & LLE_PROXY) ?
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(u_char *)IF_LLADDR(ifp) :
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(u_char *)LLADDR(dl)));
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}
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#endif
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} else {
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if (flags & LLE_EXCLUSIVE)
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LLE_WUNLOCK(lle);
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else
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LLE_RUNLOCK(lle);
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}
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} else if ((lle == NULL) && (flags & LLE_DELETE))
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error = EINVAL;
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return (error);
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}
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