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Simplify and somewhat redesign interaction between pf_purge_thread() and

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pf_purge_expired_states().

Now pf purging daemon stores the current hash table index on stack
in pf_purge_thread(), and supplies it to next iteration of
pf_purge_expired_states(). The latter returns new index back.

The important change is that whenever pf_purge_expired_states() wraps
around the array it returns immediately. This makes our knowledge about
status of states expiry run more consistent. Prior to this change it
could happen that n-th run stopped on i-th entry, and returned (1) as
full run complete, then next (n+1) full run stopped on j-th entry, where
j < i, and that broke the mark-and-sweep algorythm that saves references
rules. A referenced rule was freed, and this later lead to a crash.
This commit is contained in:
Gleb Smirnoff 2012-09-28 20:43:03 +00:00
parent 063efed28c
commit e2cfe42430
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=241039
1 changed files with 15 additions and 18 deletions
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33
sys/netpfil/pf/pf.c
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@ -282,7 +282,7 @@ static int pf_src_connlimit(struct pf_state **);
static void pf_overload_task(void *c, int pending);
static int pf_insert_src_node(struct pf_src_node **,
struct pf_rule *, struct pf_addr *, sa_family_t);
static int pf_purge_expired_states(int);
static u_int pf_purge_expired_states(u_int, int);
static void pf_purge_unlinked_rules(void);
static int pf_mtag_init(void *, int, int);
static void pf_mtag_free(struct m_tag *);
@ -1307,7 +1307,7 @@ pf_intr(void *v)
void
pf_purge_thread(void *v)
{
int fullrun;
u_int idx = 0;
CURVNET_SET((struct vnet *)v);
@ -1329,7 +1329,7 @@ pf_purge_thread(void *v)
/*
* Now purge everything.
*/
pf_purge_expired_states(V_pf_hashmask + 1);
pf_purge_expired_states(0, V_pf_hashmask);
pf_purge_expired_fragments();
pf_purge_expired_src_nodes();
@ -1352,11 +1352,11 @@ pf_purge_thread(void *v)
PF_RULES_RUNLOCK();
/* Process 1/interval fraction of the state table every run. */
fullrun = pf_purge_expired_states(V_pf_hashmask /
idx = pf_purge_expired_states(idx, V_pf_hashmask /
(V_pf_default_rule.timeout[PFTM_INTERVAL] * 10));
/* Purge other expired types every PFTM_INTERVAL seconds. */
if (fullrun) {
if (idx == 0) {
/*
* Order is important:
* - states and src nodes reference rules
@ -1533,14 +1533,11 @@ pf_free_state(struct pf_state *cur)
/*
* Called only from pf_purge_thread(), thus serialized.
*/
static int
pf_purge_expired_states(int maxcheck)
static u_int
pf_purge_expired_states(u_int i, int maxcheck)
{
static u_int i = 0;
struct pf_idhash *ih;
struct pf_state *s;
int rv = 0;
V_pf_status.states = uma_zone_get_cur(V_pf_state_z);
@ -1549,12 +1546,6 @@ pf_purge_expired_states(int maxcheck)
*/
while (maxcheck > 0) {
/* Wrap to start of hash when we hit the end. */
if (i > V_pf_hashmask) {
i = 0;
rv = 1;
}
ih = &V_pf_idhash[i];
relock:
PF_HASHROW_LOCK(ih);
@ -1574,13 +1565,19 @@ pf_purge_expired_states(int maxcheck)
s->rt_kif->pfik_flags |= PFI_IFLAG_REFS;
}
PF_HASHROW_UNLOCK(ih);
i++;
/* Return when we hit end of hash. */
if (++i > V_pf_hashmask) {
V_pf_status.states = uma_zone_get_cur(V_pf_state_z);
return (0);
}
maxcheck--;
}
V_pf_status.states = uma_zone_get_cur(V_pf_state_z);
return (rv);
return (i);
}
static void