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Prevent disappearing SAD entries by implementing MPsafe refcounting.

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"Why didn't he use SECASVAR_LOCK()/SECASVAR_UNLOCK() macros to
 synchronize access to the secasvar structure's fields?" one may ask.
There were two reasons:
1. refcount(9) is faster then mutex(9) synchronization (one atomic
   operation instead of two).
2. Those macros are not used now at all, so at some point we may decide
   to remove them entirely.

OK'ed by:	gnn
MFC after:	2 weeks
This commit is contained in:
Pawel Jakub Dawidek 2006-05-20 15:35:36 +00:00
parent 98a68a586f
commit 95708c5fe3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=158767
1 changed files with 33 additions and 20 deletions
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53
sys/netipsec/key.c
View File

@ -54,6 +54,7 @@
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/refcount.h>
#include <sys/syslog.h>
#include <net/if.h>
@ -502,14 +503,26 @@ static const char *key_getuserfqdn __P((void));
static void key_sa_chgstate __P((struct secasvar *, u_int8_t));
static struct mbuf *key_alloc_mbuf __P((int));
#define SA_ADDREF(p) do { \
(p)->refcnt++; \
IPSEC_ASSERT((p)->refcnt != 0, ("SA refcnt overflow")); \
} while (0)
#define SA_DELREF(p) do { \
IPSEC_ASSERT((p)->refcnt > 0, ("SA refcnt underflow")); \
(p)->refcnt--; \
} while (0)
static __inline void
sa_initref(struct secasvar *sav)
{
refcount_init(&sav->refcnt, 1);
}
static __inline void
sa_addref(struct secasvar *sav)
{
refcount_acquire(&sav->refcnt);
IPSEC_ASSERT(sav->refcnt != 0, ("SA refcnt overflow"));
}
static __inline int
sa_delref(struct secasvar *sav)
{
IPSEC_ASSERT(sav->refcnt > 0, ("SA refcnt underflow"));
return (refcount_release(&sav->refcnt));
}
#define SP_ADDREF(p) do { \
(p)->refcnt++; \
@ -1000,7 +1013,7 @@ key_do_allocsa_policy(struct secashead *sah, u_int state)
}
}
if (candidate) {
SA_ADDREF(candidate);
sa_addref(candidate);
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP %s cause refcnt++:%d SA:%p\n",
__func__, candidate->refcnt, candidate));
@ -1079,7 +1092,7 @@ key_allocsa(
/* check dst address */
if (key_sockaddrcmp(&dst->sa, &sav->sah->saidx.dst.sa, 0) != 0)
continue;
SA_ADDREF(sav);
sa_addref(sav);
goto done;
}
}
@ -1198,16 +1211,16 @@ key_freesav(struct secasvar **psav, const char* where, int tag)
IPSEC_ASSERT(sav != NULL, ("null sav"));
/* XXX unguarded? */
SA_DELREF(sav);
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP %s SA:%p (SPI %u) from %s:%u; refcnt now %u\n",
__func__, sav, ntohl(sav->spi), where, tag, sav->refcnt));
if (sav->refcnt == 0) {
if (sa_delref(sav)) {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP %s SA:%p (SPI %u) from %s:%u; refcnt now %u\n",
__func__, sav, ntohl(sav->spi), where, tag, sav->refcnt));
*psav = NULL;
key_delsav(sav);
} else {
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP %s SA:%p (SPI %u) from %s:%u; refcnt now %u\n",
__func__, sav, ntohl(sav->spi), where, tag, sav->refcnt));
}
}
@ -2764,7 +2777,7 @@ key_newsav(m, mhp, sah, errp, where, tag)
/* add to satree */
newsav->sah = sah;
newsav->refcnt = 1;
sa_initref(newsav);
newsav->state = SADB_SASTATE_LARVAL;
/* XXX locking??? */
@ -4822,7 +4835,7 @@ key_getsavbyseq(sah, seq)
KEY_CHKSASTATE(state, sav->state, __func__);
if (sav->seq == seq) {
SA_ADDREF(sav);
sa_addref(sav);
KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
printf("DP %s cause refcnt++:%d SA:%p\n",
__func__, sav->refcnt, sav));