freebsd-skq/sys/net/if_llatbl.h
Robert Watson dc56e98f0d Use locks specific to the lltable code, rather than borrow the ifnet
list/index locks, to protect link layer address tables.  This avoids
lock order issues during interface teardown, but maintains the bug that
sysctl copy routines may be called while a non-sleepable lock is held.

Reviewed by:	bz, kmacy
MFC after:	3 days
2009-08-25 09:52:38 +00:00

207 lines
6.5 KiB
C

/*
* Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
* Copyright (c) 2004-2008 Qing Li. All rights reserved.
* Copyright (c) 2008 Kip Macy. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifndef _NET_IF_LLATBL_H_
#define _NET_IF_LLATBL_H_
#include <sys/_rwlock.h>
#include <netinet/in.h>
struct ifnet;
struct sysctl_req;
struct rt_msghdr;
struct rt_addrinfo;
struct llentry;
LIST_HEAD(llentries, llentry);
extern struct rwlock lltable_rwlock;
#define LLTABLE_RLOCK() rw_rlock(&lltable_rwlock)
#define LLTABLE_RUNLOCK() rw_runlock(&lltable_rwlock)
#define LLTABLE_WLOCK() rw_wlock(&lltable_rwlock)
#define LLTABLE_WUNLOCK() rw_wunlock(&lltable_rwlock)
#define LLTABLE_LOCK_ASSERT() rw_assert(&lltable_rwlock, RA_LOCKED)
/*
* Code referencing llentry must at least hold
* a shared lock
*/
struct llentry {
LIST_ENTRY(llentry) lle_next;
struct rwlock lle_lock;
struct lltable *lle_tbl;
struct llentries *lle_head;
struct mbuf *la_hold;
time_t la_expire;
uint16_t la_flags;
uint16_t la_asked;
uint16_t la_preempt;
uint16_t ln_byhint;
int16_t ln_state; /* IPv6 has ND6_LLINFO_NOSTATE == -2 */
uint16_t ln_router;
time_t ln_ntick;
int lle_refcnt;
union {
uint64_t mac_aligned;
uint16_t mac16[3];
} ll_addr;
/* XXX af-private? */
union {
struct callout ln_timer_ch;
struct callout la_timer;
} lle_timer;
/* NB: struct sockaddr must immediately follow */
};
#define LLE_WLOCK(lle) rw_wlock(&(lle)->lle_lock)
#define LLE_RLOCK(lle) rw_rlock(&(lle)->lle_lock)
#define LLE_WUNLOCK(lle) rw_wunlock(&(lle)->lle_lock)
#define LLE_RUNLOCK(lle) rw_runlock(&(lle)->lle_lock)
#define LLE_DOWNGRADE(lle) rw_downgrade(&(lle)->lle_lock)
#define LLE_TRY_UPGRADE(lle) rw_try_upgrade(&(lle)->lle_lock)
#define LLE_LOCK_INIT(lle) rw_init_flags(&(lle)->lle_lock, "lle", RW_DUPOK)
#define LLE_LOCK_DESTROY(lle) rw_destroy(&(lle)->lle_lock)
#define LLE_WLOCK_ASSERT(lle) rw_assert(&(lle)->lle_lock, RA_WLOCKED)
#define LLE_IS_VALID(lle) (((lle) != NULL) && ((lle) != (void *)-1))
#define LLE_ADDREF(lle) do { \
LLE_WLOCK_ASSERT(lle); \
KASSERT((lle)->lle_refcnt >= 0, \
("negative refcnt %d", (lle)->lle_refcnt)); \
(lle)->lle_refcnt++; \
} while (0)
#define LLE_REMREF(lle) do { \
LLE_WLOCK_ASSERT(lle); \
KASSERT((lle)->lle_refcnt > 1, \
("bogus refcnt %d", (lle)->lle_refcnt)); \
(lle)->lle_refcnt--; \
} while (0)
#define LLE_FREE_LOCKED(lle) do { \
if ((lle)->lle_refcnt <= 1) \
(lle)->lle_tbl->llt_free((lle)->lle_tbl, (lle));\
else { \
(lle)->lle_refcnt--; \
LLE_WUNLOCK(lle); \
} \
/* guard against invalid refs */ \
lle = 0; \
} while (0)
#define LLE_FREE(lle) do { \
LLE_WLOCK(lle); \
if ((lle)->lle_refcnt <= 1) \
(lle)->lle_tbl->llt_free((lle)->lle_tbl, (lle));\
else { \
(lle)->lle_refcnt--; \
LLE_WUNLOCK(lle); \
} \
/* guard against invalid refs */ \
lle = NULL; \
} while (0)
#define ln_timer_ch lle_timer.ln_timer_ch
#define la_timer lle_timer.la_timer
/* XXX bad name */
#define L3_ADDR(lle) ((struct sockaddr *)(&lle[1]))
#define L3_ADDR_LEN(lle) (((struct sockaddr *)(&lle[1]))->sa_len)
#ifndef LLTBL_HASHTBL_SIZE
#define LLTBL_HASHTBL_SIZE 32 /* default 32 ? */
#endif
#ifndef LLTBL_HASHMASK
#define LLTBL_HASHMASK (LLTBL_HASHTBL_SIZE - 1)
#endif
struct lltable {
SLIST_ENTRY(lltable) llt_link;
struct llentries lle_head[LLTBL_HASHTBL_SIZE];
int llt_af;
struct ifnet *llt_ifp;
struct llentry * (*llt_new)(const struct sockaddr *, u_int);
void (*llt_free)(struct lltable *, struct llentry *);
void (*llt_prefix_free)(struct lltable *,
const struct sockaddr *prefix,
const struct sockaddr *mask);
struct llentry * (*llt_lookup)(struct lltable *, u_int flags,
const struct sockaddr *l3addr);
int (*llt_rtcheck)(struct ifnet *,
const struct sockaddr *);
int (*llt_dump)(struct lltable *,
struct sysctl_req *);
};
MALLOC_DECLARE(M_LLTABLE);
/*
* flags to be passed to arplookup.
*/
#define LLE_DELETED 0x0001 /* entry must be deleted */
#define LLE_STATIC 0x0002 /* entry is static */
#define LLE_IFADDR 0x0004 /* entry is interface addr */
#define LLE_VALID 0x0008 /* ll_addr is valid */
#define LLE_PROXY 0x0010 /* proxy entry ??? */
#define LLE_PUB 0x0020 /* publish entry ??? */
#define LLE_DELETE 0x4000 /* delete on a lookup - match LLE_IFADDR */
#define LLE_CREATE 0x8000 /* create on a lookup miss */
#define LLE_EXCLUSIVE 0x2000 /* return lle xlocked */
#define LLATBL_HASH(key, mask) \
(((((((key >> 8) ^ key) >> 8) ^ key) >> 8) ^ key) & mask)
struct lltable *lltable_init(struct ifnet *, int);
void lltable_free(struct lltable *);
void lltable_prefix_free(int, struct sockaddr *,
struct sockaddr *);
void lltable_drain(int);
int lltable_sysctl_dumparp(int, struct sysctl_req *);
void llentry_free(struct llentry *);
int llentry_update(struct llentry **, struct lltable *,
struct sockaddr *, struct ifnet *);
/*
* Generic link layer address lookup function.
*/
static __inline struct llentry *
lla_lookup(struct lltable *llt, u_int flags, const struct sockaddr *l3addr)
{
return llt->llt_lookup(llt, flags, l3addr);
}
int lla_rt_output(struct rt_msghdr *, struct rt_addrinfo *);
#endif /* _NET_IF_LLATBL_H_ */