From 2f9f28b212a2bd4948c8ceaaec33ce0123632129 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Mon, 4 Apr 2011 15:19:25 +0200 Subject: [PATCH] netfilter: ipset: references are protected by rwlock instead of mutex 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 Signed-off-by: Patrick McHardy --- include/linux/netfilter/ipset/ip_set.h | 2 +- include/linux/netfilter/ipset/ip_set_ahash.h | 3 +- net/netfilter/ipset/ip_set_bitmap_ip.c | 3 +- net/netfilter/ipset/ip_set_bitmap_ipmac.c | 3 +- net/netfilter/ipset/ip_set_bitmap_port.c | 3 +- net/netfilter/ipset/ip_set_core.c | 109 +++++++++++-------- net/netfilter/ipset/ip_set_list_set.c | 6 +- 7 files changed, 73 insertions(+), 56 deletions(-) diff --git a/include/linux/netfilter/ipset/ip_set.h b/include/linux/netfilter/ipset/ip_set.h index ec333d83f3b4..5a262e3ae715 100644 --- a/include/linux/netfilter/ipset/ip_set.h +++ b/include/linux/netfilter/ipset/ip_set.h @@ -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 */ diff --git a/include/linux/netfilter/ipset/ip_set_ahash.h b/include/linux/netfilter/ipset/ip_set_ahash.h index ec9d9bea1e37..a0196ac79051 100644 --- a/include/linux/netfilter/ipset/ip_set_ahash.h +++ b/include/linux/netfilter/ipset/ip_set_ahash.h @@ -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)); diff --git a/net/netfilter/ipset/ip_set_bitmap_ip.c b/net/netfilter/ipset/ip_set_bitmap_ip.c index bca96990218d..a113ff066928 100644 --- a/net/netfilter/ipset/ip_set_bitmap_ip.c +++ b/net/netfilter/ipset/ip_set_bitmap_ip.c @@ -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)) diff --git a/net/netfilter/ipset/ip_set_bitmap_ipmac.c b/net/netfilter/ipset/ip_set_bitmap_ipmac.c index 5e790172deff..00a33242e90c 100644 --- a/net/netfilter/ipset/ip_set_bitmap_ipmac.c +++ b/net/netfilter/ipset/ip_set_bitmap_ipmac.c @@ -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)); diff --git a/net/netfilter/ipset/ip_set_bitmap_port.c b/net/netfilter/ipset/ip_set_bitmap_port.c index 165f09b1a9cb..6b38eb8f6ed8 100644 --- a/net/netfilter/ipset/ip_set_bitmap_port.c +++ b/net/netfilter/ipset/ip_set_bitmap_port.c @@ -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)) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index d6b48230a540..e88ac3c3ed07 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -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 @@ ip_set_dump_start(struct sk_buff *skb, struct netlink_callback *cb) /* 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 */ diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c index f4a46c0d25f3..e9159e99fc4b 100644 --- a/net/netfilter/ipset/ip_set_list_set.c +++ b/net/netfilter/ipset/ip_set_list_set.c @@ -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);