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Restore the ability to keep states after parent rule deletion.

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This feature is disabled by default and was removed when dynamic states
implementation changed to be lockless. Now it is reimplemented with small
differences - when dyn_keep_states sysctl variable is enabled,
dyn_match_ipv[46]_state() function doesn't match child states of deleted
rule. And thus they are keept alive until expired. ipfw_dyn_lookup_state()
function does check that state was not orphaned, and if so, it returns
pointer to default_rule and its position in the rules map. The main visible
difference is that orphaned states still have the same rule number that
they have before parent rule deleted, because now a state has many fields
related to rule and changing them all atomically to point to default_rule
seems hard enough.

Reported by:	<lantw44 at gmail.com>
MFC after:	2 days
This commit is contained in:
Andrey V. Elsukov 2018-05-22 13:28:05 +00:00
parent 14f7050dba
commit 67ad3c0bf9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=334039
1 changed files with 30 additions and 6 deletions
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36
sys/netpfil/ipfw/ip_fw_dynamic.c
View File

@ -311,6 +311,9 @@ static VNET_DEFINE(struct callout, dyn_timeout);
static VNET_DEFINE(uint32_t, curr_max_length);
#define V_curr_max_length VNET(curr_max_length)
static VNET_DEFINE(uint32_t, dyn_keep_states);
#define V_dyn_keep_states VNET(dyn_keep_states)
static VNET_DEFINE(uma_zone_t, dyn_data_zone);
static VNET_DEFINE(uma_zone_t, dyn_parent_zone);
static VNET_DEFINE(uma_zone_t, dyn_ipv4_zone);
@ -361,6 +364,7 @@ static VNET_DEFINE(uint32_t, dyn_max); /* max # of dynamic states */
static VNET_DEFINE(uint32_t, dyn_count); /* number of states */
static VNET_DEFINE(uint32_t, dyn_parent_max); /* max # of parent states */
static VNET_DEFINE(uint32_t, dyn_parent_count); /* number of parent states */
#define V_dyn_max VNET(dyn_max)
#define V_dyn_count VNET(dyn_count)
#define V_dyn_parent_max VNET(dyn_parent_max)
@ -475,6 +479,10 @@ SYSCTL_U32(_net_inet_ip_fw, OID_AUTO, dyn_short_lifetime,
SYSCTL_U32(_net_inet_ip_fw, OID_AUTO, dyn_keepalive,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keepalive), 0,
"Enable keepalives for dynamic states.");
SYSCTL_U32(_net_inet_ip_fw, OID_AUTO, dyn_keep_states,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(dyn_keep_states), 0,
"Do not flush dynamic states on rule deletion");
#ifdef IPFIREWALL_DYNDEBUG
#define DYN_DEBUG(fmt, ...) do { \
@ -1387,18 +1395,32 @@ ipfw_dyn_lookup_state(const struct ip_fw_args *args, const void *ulp,
* that will be added into head of this bucket.
* And the state that we currently have matched
* should be deleted by dyn_expire_states().
*
* In case when dyn_keep_states is enabled, return
* pointer to default rule and corresponding f_pos
* value.
* XXX: In this case we lose the cache efficiency,
* since f_pos is not cached, because it seems
* there is no easy way to atomically switch
* all fields related to parent rule of given
* state.
*/
if (V_layer3_chain.map[data->f_pos] == rule)
if (V_layer3_chain.map[data->f_pos] == rule) {
data->chain_id = V_layer3_chain.id;
else {
info->f_pos = data->f_pos;
} else if (V_dyn_keep_states != 0) {
rule = V_layer3_chain.default_rule;
info->f_pos = V_layer3_chain.n_rules - 1;
} else {
rule = NULL;
info->direction = MATCH_NONE;
DYN_DEBUG("rule %p [%u, %u] is considered "
"invalid in data %p", rule, data->ruleid,
data->rulenum, data);
/* info->f_pos doesn't matter here. */
}
}
info->f_pos = data->f_pos;
} else
info->f_pos = data->f_pos;
}
DYNSTATE_CRITICAL_EXIT();
#if 0
@ -2099,7 +2121,8 @@ dyn_match_ipv4_state(struct dyn_ipv4_state *s, const ipfw_range_tlv *rt)
if (s->type == O_LIMIT)
return (dyn_match_range(s->data->rulenum, s->data->set, rt));
if (dyn_match_range(s->data->rulenum, s->data->set, rt))
if (V_dyn_keep_states == 0 &&
dyn_match_range(s->data->rulenum, s->data->set, rt))
return (1);
return (0);
@ -2117,7 +2140,8 @@ dyn_match_ipv6_state(struct dyn_ipv6_state *s, const ipfw_range_tlv *rt)
if (s->type == O_LIMIT)
return (dyn_match_range(s->data->rulenum, s->data->set, rt));
if (dyn_match_range(s->data->rulenum, s->data->set, rt))
if (V_dyn_keep_states == 0 &&
dyn_match_range(s->data->rulenum, s->data->set, rt))
return (1);
return (0);