d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
8646e68235
freebsd-skq/sys/net/if_llatbl.h
melifaro 5acc305ae0 Remove LLE read lock from IPv6 fast path. 
LLE structure is mostly unchanged during its lifecycle: there are only 2
things relevant for fast path lookup code:
1) link-level address change. Since r286722, these updates are performed
  under AFDATA WLOCK.
2) Some sort of feedback indicating that this particular entry is used so
  we send NS to perform reachability verification instead of expiring entry.
  The only signal that is needed from fast path is something like binary
  yes/no.
The latter is solved by the following changes:

Special r_skip_req (introduced in D3688) value is used for fast path feedback.
  It is read lockless by fast path, but updated under req_mutex mutex. If this
  field is non-zero, then fast path will acquire lock and set it back to 0.

After transitioning to STALE state, callout timer is armed to run each
  V_nd6_delay seconds to make sure that if packet was transmitted at the start
  of given interval, we would be able to switch to PROBE state in V_nd6_delay
  seconds as user expects.
(in STALE state) timer is rescheduled until original V_nd6_gctimer expires
  keeping lle in STALE state (remaining timer value stored in lle_remtime).
(in STALE state) timer is rescheduled if packet was transmitted less that
  V_nd6_delay seconds ago to make sure we transition to PROBE state exactly
  after V_n6_delay seconds.

As a result, all packets towards lle in REACHABLE/STALE/PROBE states are handled
  by fast path without acquiring lle read lock.

Differential Revision:		https://reviews.freebsd.org/D3780
2015-12-13 07:39:49 +00:00

265 lines
9.0 KiB
C
Raw Blame History

/*
* 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;
union {
struct in_addr addr4;
struct in6_addr addr6;
} r_l3addr;
union {
uint64_t mac_aligned;
uint16_t mac16[3];
uint8_t mac8[20]; /* IB needs 20 bytes. */
} ll_addr;
uint16_t r_flags; /* LLE runtime flags */
uint16_t r_skip_req; /* feedback from fast path */
uint64_t spare1;
struct lltable *lle_tbl;
struct llentries *lle_head;
void (*lle_free)(struct llentry *);
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;
int16_t ln_state; /* IPv6 has ND6_LLINFO_NOSTATE == -2 */
uint16_t ln_router;
time_t ln_ntick;
time_t lle_remtime; /* Real time remaining */
time_t lle_hittime; /* Time when r_skip_req was unset */
int lle_refcnt;
LIST_ENTRY(llentry) lle_chain; /* chain of deleted items */
struct callout lle_timer;
struct rwlock lle_lock;
struct mtx req_mtx;
};
#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_REQ_INIT(lle) mtx_init(&(lle)->req_mtx, "lle req", \
NULL, MTX_DEF)
#define LLE_REQ_DESTROY(lle) mtx_destroy(&(lle)->req_mtx)
#define LLE_REQ_LOCK(lle) mtx_lock(&(lle)->req_mtx)
#define LLE_REQ_UNLOCK(lle) mtx_unlock(&(lle)->req_mtx)
#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 on lle %p", \
(lle)->lle_refcnt, (lle))); \
(lle)->lle_refcnt++; \
} while (0)
#define LLE_REMREF(lle) do { \
LLE_WLOCK_ASSERT(lle); \
KASSERT((lle)->lle_refcnt > 0, \
("bogus refcnt %d on lle %p", \
(lle)->lle_refcnt, (lle))); \
(lle)->lle_refcnt--; \
} while (0)
#define LLE_FREE_LOCKED(lle) do { \
if ((lle)->lle_refcnt == 1) \
(lle)->lle_free(lle); \
else { \
LLE_REMREF(lle); \
LLE_WUNLOCK(lle); \
} \
/* guard against invalid refs */ \
(lle) = NULL; \
} while (0)
#define LLE_FREE(lle) do { \
LLE_WLOCK(lle); \
LLE_FREE_LOCKED(lle); \
} while (0)
typedef struct llentry *(llt_lookup_t)(struct lltable *, u_int flags,
const struct sockaddr *l3addr);
typedef struct llentry *(llt_alloc_t)(struct lltable *, u_int flags,
const struct sockaddr *l3addr);
typedef void (llt_delete_t)(struct lltable *, struct llentry *);
typedef void (llt_prefix_free_t)(struct lltable *,
const struct sockaddr *addr, const struct sockaddr *mask, u_int flags);
typedef int (llt_dump_entry_t)(struct lltable *, struct llentry *,
struct sysctl_req *);
typedef uint32_t (llt_hash_t)(const struct llentry *, uint32_t);
typedef int (llt_match_prefix_t)(const struct sockaddr *,
const struct sockaddr *, u_int, struct llentry *);
typedef void (llt_free_entry_t)(struct lltable *, struct llentry *);
typedef void (llt_fill_sa_entry_t)(const struct llentry *, struct sockaddr *);
typedef void (llt_free_tbl_t)(struct lltable *);
typedef void (llt_link_entry_t)(struct lltable *, struct llentry *);
typedef void (llt_unlink_entry_t)(struct llentry *);
typedef int (llt_foreach_cb_t)(struct lltable *, struct llentry *, void *);
typedef int (llt_foreach_entry_t)(struct lltable *, llt_foreach_cb_t *, void *);
struct lltable {
SLIST_ENTRY(lltable) llt_link;
int llt_af;
int llt_hsize;
struct llentries *lle_head;
struct ifnet *llt_ifp;
llt_lookup_t *llt_lookup;
llt_alloc_t *llt_alloc_entry;
llt_delete_t *llt_delete_entry;
llt_prefix_free_t *llt_prefix_free;
llt_dump_entry_t *llt_dump_entry;
llt_hash_t *llt_hash;
llt_match_prefix_t *llt_match_prefix;
llt_free_entry_t *llt_free_entry;
llt_foreach_entry_t *llt_foreach_entry;
llt_link_entry_t *llt_link_entry;
llt_unlink_entry_t *llt_unlink_entry;
llt_fill_sa_entry_t *llt_fill_sa_entry;
llt_free_tbl_t *llt_free_tbl;
};
MALLOC_DECLARE(M_LLTABLE);
/*
* LLentry flags
*/
#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_REDIRECT 0x0010 /* installed by redirect; has host rtentry */
#define LLE_PUB 0x0020 /* publish entry ??? */
#define LLE_LINKED 0x0040 /* linked to lookup structure */
/* LLE request flags */
#define LLE_EXCLUSIVE 0x2000 /* return lle xlocked */
#define LLE_UNLOCKED 0x4000 /* return lle unlocked */
/* LLE flags used by fastpath code */
#define RLLE_VALID 0x0001 /* entry is valid */
#define RLLE_IFADDR LLE_IFADDR /* entry is ifaddr */
#define LLATBL_HASH(key, mask) \
(((((((key >> 8) ^ key) >> 8) ^ key) >> 8) ^ key) & mask)
struct lltable *lltable_allocate_htbl(uint32_t hsize);
void lltable_free(struct lltable *);
void lltable_link(struct lltable *llt);
void lltable_prefix_free(int, struct sockaddr *,
struct sockaddr *, u_int);
#if 0
void lltable_drain(int);
#endif
int lltable_sysctl_dumparp(int, struct sysctl_req *);
size_t llentry_free(struct llentry *);
struct llentry *llentry_alloc(struct ifnet *, struct lltable *,
struct sockaddr_storage *);
/* helper functions */
size_t lltable_drop_entry_queue(struct llentry *);
void lltable_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
const char *lladdr);
int lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
const char *lladdr);
struct llentry *lltable_alloc_entry(struct lltable *llt, u_int flags,
const struct sockaddr *l4addr);
void lltable_free_entry(struct lltable *llt, struct llentry *lle);
int lltable_delete_addr(struct lltable *llt, u_int flags,
const struct sockaddr *l3addr);
void lltable_link_entry(struct lltable *llt, struct llentry *lle);
void lltable_unlink_entry(struct lltable *llt, struct llentry *lle);
void lltable_fill_sa_entry(const struct llentry *lle, struct sockaddr *sa);
struct ifnet *lltable_get_ifp(const struct lltable *llt);
int lltable_get_af(const struct lltable *llt);
int lltable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f,
void *farg);
/*
* 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 *);
#include <sys/eventhandler.h>
enum {
LLENTRY_RESOLVED,
LLENTRY_TIMEDOUT,
LLENTRY_DELETED,
LLENTRY_EXPIRED,
};
typedef void (*lle_event_fn)(void *, struct llentry *, int);
EVENTHANDLER_DECLARE(lle_event, lle_event_fn);
#endif /* _NET_IF_LLATBL_H_ */
Reference in New Issue View Git Blame Copy Permalink