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netfilter: ipset: references are protected by rwlock instead of mutex

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The timeout variant of the list:set type must reference the member sets.
However, its garbage collector runs at timer interrupt so the mutex
protection of the references is a no go. Therefore the reference protection
is converted to rwlock.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Jozsef Kadlecsik 2011-04-04 15:19:25 +02:00 committed by Patrick McHardy
parent 512d06b5b6
commit 2f9f28b212
7 changed files with 73 additions and 56 deletions
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2
include/linux/netfilter/ipset/ip_set.h
View File

@ -293,7 +293,7 @@ struct ip_set {
/* Lock protecting the set data */
rwlock_t lock;
/* References to the set */
atomic_t ref;
u32 ref;
/* The core set type */
struct ip_set_type *type;
/* The type variant doing the real job */

3
include/linux/netfilter/ipset/ip_set_ahash.h
View File

@ -515,8 +515,7 @@ type_pf_head(struct ip_set *set, struct sk_buff *skb)
if (h->netmask != HOST_MASK)
NLA_PUT_U8(skb, IPSET_ATTR_NETMASK, h->netmask);
#endif
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
htonl(atomic_read(&set->ref) - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE, htonl(memsize));
if (with_timeout(h->timeout))
NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT, htonl(h->timeout));

3
net/netfilter/ipset/ip_set_bitmap_ip.c
View File

@ -338,8 +338,7 @@ bitmap_ip_head(struct ip_set *set, struct sk_buff *skb)
NLA_PUT_IPADDR4(skb, IPSET_ATTR_IP_TO, htonl(map->last_ip));
if (map->netmask != 32)
NLA_PUT_U8(skb, IPSET_ATTR_NETMASK, map->netmask);
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
htonl(atomic_read(&set->ref) - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE,
htonl(sizeof(*map) + map->memsize));
if (with_timeout(map->timeout))

3
net/netfilter/ipset/ip_set_bitmap_ipmac.c
View File

@ -434,8 +434,7 @@ bitmap_ipmac_head(struct ip_set *set, struct sk_buff *skb)
goto nla_put_failure;
NLA_PUT_IPADDR4(skb, IPSET_ATTR_IP, htonl(map->first_ip));
NLA_PUT_IPADDR4(skb, IPSET_ATTR_IP_TO, htonl(map->last_ip));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
htonl(atomic_read(&set->ref) - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE,
htonl(sizeof(*map)
+ (map->last_ip - map->first_ip + 1) * map->dsize));

3
net/netfilter/ipset/ip_set_bitmap_port.c
View File

@ -320,8 +320,7 @@ bitmap_port_head(struct ip_set *set, struct sk_buff *skb)
goto nla_put_failure;
NLA_PUT_NET16(skb, IPSET_ATTR_PORT, htons(map->first_port));
NLA_PUT_NET16(skb, IPSET_ATTR_PORT_TO, htons(map->last_port));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
htonl(atomic_read(&set->ref) - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE,
htonl(sizeof(*map) + map->memsize));
if (with_timeout(map->timeout))

109
net/netfilter/ipset/ip_set_core.c
View File

@ -26,6 +26,7 @@
static LIST_HEAD(ip_set_type_list); /* all registered set types */
static DEFINE_MUTEX(ip_set_type_mutex); /* protects ip_set_type_list */
static DEFINE_RWLOCK(ip_set_ref_lock); /* protects the set refs */
static struct ip_set **ip_set_list; /* all individual sets */
static ip_set_id_t ip_set_max = CONFIG_IP_SET_MAX; /* max number of sets */
@ -301,13 +302,18 @@ EXPORT_SYMBOL_GPL(ip_set_get_ipaddr6);
static inline void
__ip_set_get(ip_set_id_t index)
{
atomic_inc(&ip_set_list[index]->ref);
write_lock_bh(&ip_set_ref_lock);
ip_set_list[index]->ref++;
write_unlock_bh(&ip_set_ref_lock);
}
static inline void
__ip_set_put(ip_set_id_t index)
{
atomic_dec(&ip_set_list[index]->ref);
write_lock_bh(&ip_set_ref_lock);
BUG_ON(ip_set_list[index]->ref == 0);
ip_set_list[index]->ref--;
write_unlock_bh(&ip_set_ref_lock);
}
/*
@ -324,7 +330,7 @@ ip_set_test(ip_set_id_t index, const struct sk_buff *skb,
struct ip_set *set = ip_set_list[index];
int ret = 0;
BUG_ON(set == NULL || atomic_read(&set->ref) == 0);
BUG_ON(set == NULL);
pr_debug("set %s, index %u\n", set->name, index);
if (dim < set->type->dimension ||
@ -356,7 +362,7 @@ ip_set_add(ip_set_id_t index, const struct sk_buff *skb,
struct ip_set *set = ip_set_list[index];
int ret;
BUG_ON(set == NULL || atomic_read(&set->ref) == 0);
BUG_ON(set == NULL);
pr_debug("set %s, index %u\n", set->name, index);
if (dim < set->type->dimension ||
@ -378,7 +384,7 @@ ip_set_del(ip_set_id_t index, const struct sk_buff *skb,
struct ip_set *set = ip_set_list[index];
int ret = 0;
BUG_ON(set == NULL || atomic_read(&set->ref) == 0);
BUG_ON(set == NULL);
pr_debug("set %s, index %u\n", set->name, index);
if (dim < set->type->dimension ||
@ -397,7 +403,6 @@ EXPORT_SYMBOL_GPL(ip_set_del);
* Find set by name, reference it once. The reference makes sure the
* thing pointed to, does not go away under our feet.
*
* The nfnl mutex must already be activated.
*/
ip_set_id_t
ip_set_get_byname(const char *name, struct ip_set **set)
@ -423,15 +428,12 @@ EXPORT_SYMBOL_GPL(ip_set_get_byname);
* reference count by 1. The caller shall not assume the index
* to be valid, after calling this function.
*
* The nfnl mutex must already be activated.
*/
void
ip_set_put_byindex(ip_set_id_t index)
{
if (ip_set_list[index] != NULL) {
BUG_ON(atomic_read(&ip_set_list[index]->ref) == 0);
if (ip_set_list[index] != NULL)
__ip_set_put(index);
}
}
EXPORT_SYMBOL_GPL(ip_set_put_byindex);
@ -441,7 +443,6 @@ EXPORT_SYMBOL_GPL(ip_set_put_byindex);
* can't be destroyed. The set cannot be renamed due to
* the referencing either.
*
* The nfnl mutex must already be activated.
*/
const char *
ip_set_name_byindex(ip_set_id_t index)
@ -449,7 +450,7 @@ ip_set_name_byindex(ip_set_id_t index)
const struct ip_set *set = ip_set_list[index];
BUG_ON(set == NULL);
BUG_ON(atomic_read(&set->ref) == 0);
BUG_ON(set->ref == 0);
/* Referenced, so it's safe */
return set->name;
@ -515,10 +516,7 @@ void
ip_set_nfnl_put(ip_set_id_t index)
{
nfnl_lock();
if (ip_set_list[index] != NULL) {
BUG_ON(atomic_read(&ip_set_list[index]->ref) == 0);
__ip_set_put(index);
}
ip_set_put_byindex(index);
nfnl_unlock();
}
EXPORT_SYMBOL_GPL(ip_set_nfnl_put);
@ -526,7 +524,7 @@ EXPORT_SYMBOL_GPL(ip_set_nfnl_put);
/*
* Communication protocol with userspace over netlink.
*
* We already locked by nfnl_lock.
* The commands are serialized by the nfnl mutex.
*/
static inline bool
@ -657,7 +655,6 @@ ip_set_create(struct sock *ctnl, struct sk_buff *skb,
return -ENOMEM;
rwlock_init(&set->lock);
strlcpy(set->name, name, IPSET_MAXNAMELEN);
atomic_set(&set->ref, 0);
set->family = family;
/*
@ -690,8 +687,8 @@ ip_set_create(struct sock *ctnl, struct sk_buff *skb,
/*
* Here, we have a valid, constructed set and we are protected
* by nfnl_lock. Find the first free index in ip_set_list and
* check clashing.
* by the nfnl mutex. Find the first free index in ip_set_list
* and check clashing.
*/
if ((ret = find_free_id(set->name, &index, &clash)) != 0) {
/* If this is the same set and requested, ignore error */
@ -751,31 +748,51 @@ ip_set_destroy(struct sock *ctnl, struct sk_buff *skb,
const struct nlattr * const attr[])
{
ip_set_id_t i;
int ret = 0;
if (unlikely(protocol_failed(attr)))
return -IPSET_ERR_PROTOCOL;
/* References are protected by the nfnl mutex */
/* Commands are serialized and references are
* protected by the ip_set_ref_lock.
* External systems (i.e. xt_set) must call
* ip_set_put|get_nfnl_* functions, that way we
* can safely check references here.
*
* list:set timer can only decrement the reference
* counter, so if it's already zero, we can proceed
* without holding the lock.
*/
read_lock_bh(&ip_set_ref_lock);
if (!attr[IPSET_ATTR_SETNAME]) {
for (i = 0; i < ip_set_max; i++) {
if (ip_set_list[i] != NULL &&
(atomic_read(&ip_set_list[i]->ref)))
return -IPSET_ERR_BUSY;
if (ip_set_list[i] != NULL && ip_set_list[i]->ref) {
ret = IPSET_ERR_BUSY;
goto out;
}
}
read_unlock_bh(&ip_set_ref_lock);
for (i = 0; i < ip_set_max; i++) {
if (ip_set_list[i] != NULL)
ip_set_destroy_set(i);
}
} else {
i = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME]));
if (i == IPSET_INVALID_ID)
return -ENOENT;
else if (atomic_read(&ip_set_list[i]->ref))
return -IPSET_ERR_BUSY;
if (i == IPSET_INVALID_ID) {
ret = -ENOENT;
goto out;
} else if (ip_set_list[i]->ref) {
ret = -IPSET_ERR_BUSY;
goto out;
}
read_unlock_bh(&ip_set_ref_lock);
ip_set_destroy_set(i);
}
return 0;
out:
read_unlock_bh(&ip_set_ref_lock);
return ret;
}
/* Flush sets */
@ -834,6 +851,7 @@ ip_set_rename(struct sock *ctnl, struct sk_buff *skb,
struct ip_set *set;
const char *name2;
ip_set_id_t i;
int ret = 0;
if (unlikely(protocol_failed(attr) ||
attr[IPSET_ATTR_SETNAME] == NULL ||
@ -843,25 +861,33 @@ ip_set_rename(struct sock *ctnl, struct sk_buff *skb,
set = find_set(nla_data(attr[IPSET_ATTR_SETNAME]));
if (set == NULL)
return -ENOENT;
if (atomic_read(&set->ref) != 0)
return -IPSET_ERR_REFERENCED;
read_lock_bh(&ip_set_ref_lock);
if (set->ref != 0) {
ret = -IPSET_ERR_REFERENCED;
goto out;
}
name2 = nla_data(attr[IPSET_ATTR_SETNAME2]);
for (i = 0; i < ip_set_max; i++) {
if (ip_set_list[i] != NULL &&
STREQ(ip_set_list[i]->name, name2))
return -IPSET_ERR_EXIST_SETNAME2;
STREQ(ip_set_list[i]->name, name2)) {
ret = -IPSET_ERR_EXIST_SETNAME2;
goto out;
}
}
strncpy(set->name, name2, IPSET_MAXNAMELEN);
return 0;
out:
read_unlock_bh(&ip_set_ref_lock);
return ret;
}
/* Swap two sets so that name/index points to the other.
* References and set names are also swapped.
*
* We are protected by the nfnl mutex and references are
* manipulated only by holding the mutex. The kernel interfaces
* The commands are serialized by the nfnl mutex and references are
* protected by the ip_set_ref_lock. The kernel interfaces
* do not hold the mutex but the pointer settings are atomic
* so the ip_set_list always contains valid pointers to the sets.
*/
@ -874,7 +900,6 @@ ip_set_swap(struct sock *ctnl, struct sk_buff *skb,
struct ip_set *from, *to;
ip_set_id_t from_id, to_id;
char from_name[IPSET_MAXNAMELEN];
u32 from_ref;
if (unlikely(protocol_failed(attr) ||
attr[IPSET_ATTR_SETNAME] == NULL ||
@ -899,17 +924,15 @@ ip_set_swap(struct sock *ctnl, struct sk_buff *skb,
from->type->family == to->type->family))
return -IPSET_ERR_TYPE_MISMATCH;
/* No magic here: ref munging protected by the nfnl_lock */
strncpy(from_name, from->name, IPSET_MAXNAMELEN);
from_ref = atomic_read(&from->ref);
strncpy(from->name, to->name, IPSET_MAXNAMELEN);
atomic_set(&from->ref, atomic_read(&to->ref));
strncpy(to->name, from_name, IPSET_MAXNAMELEN);
atomic_set(&to->ref, from_ref);
write_lock_bh(&ip_set_ref_lock);
swap(from->ref, to->ref);
ip_set_list[from_id] = to;
ip_set_list[to_id] = from;
write_unlock_bh(&ip_set_ref_lock);
return 0;
}
@ -926,7 +949,7 @@ ip_set_dump_done(struct netlink_callback *cb)
{
if (cb->args[2]) {
pr_debug("release set %s\n", ip_set_list[cb->args[1]]->name);
__ip_set_put((ip_set_id_t) cb->args[1]);
ip_set_put_byindex((ip_set_id_t) cb->args[1]);
}
return 0;
}
@ -1068,7 +1091,7 @@ release_refcount:
/* If there was an error or set is done, release set */
if (ret || !cb->args[2]) {
pr_debug("release set %s\n", ip_set_list[index]->name);
__ip_set_put(index);
ip_set_put_byindex(index);
}
/* If we dump all sets, continue with dumping last ones */

6
net/netfilter/ipset/ip_set_list_set.c
View File

@ -366,8 +366,7 @@ list_set_head(struct ip_set *set, struct sk_buff *skb)
NLA_PUT_NET32(skb, IPSET_ATTR_SIZE, htonl(map->size));
if (with_timeout(map->timeout))
NLA_PUT_NET32(skb, IPSET_ATTR_TIMEOUT, htonl(map->timeout));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES,
htonl(atomic_read(&set->ref) - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1));
NLA_PUT_NET32(skb, IPSET_ATTR_MEMSIZE,
htonl(sizeof(*map) + map->size * map->dsize));
ipset_nest_end(skb, nested);
@ -457,8 +456,7 @@ list_set_gc(unsigned long ul_set)
struct list_set *map = set->data;
struct set_telem *e;
u32 i;
/* nfnl_lock should be called */
write_lock_bh(&set->lock);
for (i = 0; i < map->size; i++) {
e = list_set_telem(map, i);