freebsd-skq/sys/net/if_llatbl.h
George V. Neville-Neil e162ea60d4 Add a queue to hold packets while we await an ARP reply.
When a fast machine first brings up some non TCP networking program
it is quite possible that we will drop packets due to the fact that
only one packet can be held per ARP entry.  This leads to packets
being missed when a program starts or restarts if the ARP data is
not currently in the ARP cache.

This code adds a new sysctl, net.link.ether.inet.maxhold, which defines
a system wide maximum number of packets to be held in each ARP entry.
Up to maxhold packets are queued until an ARP reply is received or
the ARP times out.  The default setting is the old value of 1
which has been part of the BSD networking code since time
immemorial.

Expose the time we hold an incomplete ARP entry by adding
the sysctl net.link.ether.inet.wait, which defaults to 20
seconds, the value used when the new ARP code was added..

Reviewed by:	bz, rpaulo
MFC after: 3 weeks
2010-11-12 22:03:02 +00:00

210 lines
6.6 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;
int la_numheld; /* # of packets currently held */
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 *, u_int flags,
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 *);
#if 0
void lltable_drain(int);
#endif
int lltable_sysctl_dumparp(int, struct sysctl_req *);
size_t llentry_free(struct llentry *);
int llentry_update(struct llentry **, struct lltable *,
struct sockaddr_storage *, 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_ */