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Order IPsec policies by a pseudo-priority based on the traffic selectors 

This allows a simple lookup, i.e. just use the first policy that matches
a given IP packet.
This commit is contained in:
Tobias Brunner 2012-07-13 14:41:45 +02:00
parent f1b4238311
commit ed1f0c234f
1 changed files with 127 additions and 28 deletions
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155
src/libipsec/ipsec_policy_mgr.c
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@ -19,13 +19,12 @@
#include "ipsec_policy.h"
#include <debug.h>
#include <library.h>
#include <ipsec/ipsec_types.h>
#include <selectors/traffic_selector.h>
#include <threading/rwlock.h>
#include <utils/host.h>
#include <utils/linked_list.h>
/** Base priority for installed policies */
#define PRIO_BASE 512
typedef struct private_ipsec_policy_mgr_t private_ipsec_policy_mgr_t;
/**
@ -39,25 +38,101 @@ struct private_ipsec_policy_mgr_t {
ipsec_policy_mgr_t public;
/**
* Installed policies
* Installed policies (ipsec_policy_entry_t*)
*/
linked_list_t *policies;
/**
* Lock to safely access policies
* Lock to safely access the list of policies
*/
rwlock_t *lock;
};
static bool match_policy(ipsec_policy_t *policy, ipsec_policy_t *other_policy)
/**
* Helper struct to store policies in a list sorted by the same pseudo-priority
* used by the NETLINK kernel interface.
*/
typedef struct {
/**
* Priority used to sort policies
*/
u_int32_t priority;
/**
* The policy
*/
ipsec_policy_t *policy;
} ipsec_policy_entry_t;
/**
* Calculate the pseudo-priority to sort policies. This is the same algorithm
* used by the NETLINK kernel interface (i.e. high priority -> low value).
*/
static u_int32_t calculate_priority(policy_priority_t policy_priority,
traffic_selector_t *src,
traffic_selector_t *dst)
{
return policy->match(policy, other_policy->get_source_ts(other_policy),
other_policy->get_destination_ts(other_policy),
other_policy->get_direction(other_policy),
other_policy->get_reqid(other_policy),
(mark_t){ .value = 0, },
other_policy->get_priority(other_policy));
u_int32_t priority = PRIO_BASE;
u_int16_t port;
u_int8_t mask, proto;
host_t *net;
switch (policy_priority)
{
case POLICY_PRIORITY_FALLBACK:
priority <<= 1;
/* fall-through */
case POLICY_PRIORITY_ROUTED:
priority <<= 1;
/* fall-through */
case POLICY_PRIORITY_DEFAULT:
break;
}
/* calculate priority based on selector size, small size = high prio */
src->to_subnet(src, &net, &mask);
priority -= mask;
proto = src->get_protocol(src);
port = net->get_port(net);
net->destroy(net);
dst->to_subnet(dst, &net, &mask);
priority -= mask;
proto = max(proto, dst->get_protocol(dst));
port = max(port, net->get_port(net));
net->destroy(net);
priority <<= 2; /* make some room for the two flags */
priority += port ? 0 : 2;
priority += proto ? 0 : 1;
return priority;
}
/**
* Create a policy entry
*/
static ipsec_policy_entry_t *policy_entry_create(ipsec_policy_t *policy)
{
ipsec_policy_entry_t *this;
INIT(this,
.policy = policy,
.priority = calculate_priority(policy->get_priority(policy),
policy->get_source_ts(policy),
policy->get_destination_ts(policy)),
);
return this;
}
/**
* Destroy a policy entry
*/
static void policy_entry_destroy(ipsec_policy_entry_t *this)
{
this->policy->destroy(this->policy);
free(this);
}
METHOD(ipsec_policy_mgr_t, add_policy, status_t,
@ -66,20 +141,33 @@ METHOD(ipsec_policy_mgr_t, add_policy, status_t,
policy_dir_t direction, policy_type_t type, ipsec_sa_cfg_t *sa, mark_t mark,
policy_priority_t priority)
{
enumerator_t *enumerator;
ipsec_policy_entry_t *entry, *current;
ipsec_policy_t *policy;
if (type != POLICY_IPSEC || direction == POLICY_FWD)
{ /* we ignore these policies as we currently have no use for them */
return SUCCESS;
}
DBG2(DBG_ESP, "adding policy %R === %R %N", src_ts, dst_ts,
policy_dir_names, direction);
policy = ipsec_policy_create(src, dst, src_ts, dst_ts, direction, type, sa,
mark, priority);
entry = policy_entry_create(policy);
this->lock->write_lock(this->lock);
if (this->policies->find_first(this->policies, (void*)match_policy,
NULL, policy) != SUCCESS)
enumerator = this->policies->create_enumerator(this->policies);
while (enumerator->enumerate(enumerator, (void**)&current))
{
this->policies->insert_last(this->policies, policy);
}
else
{
policy->destroy(policy);
if (current->priority >= entry->priority)
{
break;
}
}
this->policies->insert_before(this->policies, enumerator, entry);
enumerator->destroy(enumerator);
this->lock->unlock(this->lock);
return SUCCESS;
}
@ -87,17 +175,28 @@ METHOD(ipsec_policy_mgr_t, add_policy, status_t,
METHOD(ipsec_policy_mgr_t, del_policy, status_t,
private_ipsec_policy_mgr_t *this, traffic_selector_t *src_ts,
traffic_selector_t *dst_ts, policy_dir_t direction, u_int32_t reqid,
mark_t mark, policy_priority_t priority)
mark_t mark, policy_priority_t policy_priority)
{
enumerator_t *enumerator;
ipsec_policy_t *current, *found = NULL;
ipsec_policy_entry_t *current, *found = NULL;
u_int32_t priority;
if (direction == POLICY_FWD)
{ /* we ignore these policies as we currently have no use for them */
return SUCCESS;
}
DBG2(DBG_ESP, "deleting policy %R === %R %N", src_ts, dst_ts,
policy_dir_names, direction);
priority = calculate_priority(policy_priority, src_ts, dst_ts);
this->lock->write_lock(this->lock);
enumerator = this->policies->create_enumerator(this->policies);
while (enumerator->enumerate(enumerator, (void**)&current))
{
if (current->match(current, src_ts, dst_ts, direction, reqid,
mark, priority))
if (current->priority == priority &&
current->policy->match(current->policy, src_ts, dst_ts, direction,
reqid, mark, policy_priority))
{
this->policies->remove_at(this->policies, enumerator);
found = current;
@ -108,7 +207,7 @@ METHOD(ipsec_policy_mgr_t, del_policy, status_t,
this->lock->unlock(this->lock);
if (found)
{
found->destroy(found);
policy_entry_destroy(found);
return SUCCESS;
}
return FAILED;
@ -117,15 +216,15 @@ METHOD(ipsec_policy_mgr_t, del_policy, status_t,
METHOD(ipsec_policy_mgr_t, flush_policies, status_t,
private_ipsec_policy_mgr_t *this)
{
ipsec_policy_t *policy;
ipsec_policy_entry_t *entry;
DBG2(DBG_ESP, "flushing policies");
this->lock->write_lock(this->lock);
while (this->policies->remove_last(this->policies,
(void**)&policy) == SUCCESS)
(void**)&entry) == SUCCESS)
{
policy->destroy(policy);
policy_entry_destroy(entry);
}
this->lock->unlock(this->lock);
return SUCCESS;