From 58a3c9bb0c69f8517c2243cd0912b3f87b4f868c Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 31 Jan 2008 04:36:54 -0800 Subject: [PATCH] [NETFILTER]: nf_conntrack: use RCU for conntrack helpers Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/net/netfilter/nf_conntrack_helper.h | 4 -- net/netfilter/nf_conntrack_helper.c | 58 ++++++--------------- net/netfilter/nf_conntrack_netlink.c | 9 ++-- 3 files changed, 21 insertions(+), 50 deletions(-) diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h index 2f3af00643cf..4ca125e9b3ce 100644 --- a/include/net/netfilter/nf_conntrack_helper.h +++ b/include/net/netfilter/nf_conntrack_helper.h @@ -42,13 +42,9 @@ struct nf_conntrack_helper extern struct nf_conntrack_helper * __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple); -extern struct nf_conntrack_helper * -nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple); - extern struct nf_conntrack_helper * __nf_conntrack_helper_find_byname(const char *name); -extern void nf_ct_helper_put(struct nf_conntrack_helper *helper); extern int nf_conntrack_helper_register(struct nf_conntrack_helper *); extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *); diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index 96aa637c0932..42f781fcba64 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -28,6 +28,7 @@ #include #include +static DEFINE_MUTEX(nf_ct_helper_mutex); static struct hlist_head *nf_ct_helper_hash __read_mostly; static unsigned int nf_ct_helper_hsize __read_mostly; static unsigned int nf_ct_helper_count __read_mostly; @@ -54,42 +55,13 @@ __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple) return NULL; h = helper_hash(tuple); - hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) { + hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) { if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask)) return helper; } return NULL; } - -struct nf_conntrack_helper * -nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple) -{ - struct nf_conntrack_helper *helper; - - /* need nf_conntrack_lock to assure that helper exists until - * try_module_get() is called */ - read_lock_bh(&nf_conntrack_lock); - - helper = __nf_ct_helper_find(tuple); - if (helper) { - /* need to increase module usage count to assure helper will - * not go away while the caller is e.g. busy putting a - * conntrack in the hash that uses the helper */ - if (!try_module_get(helper->me)) - helper = NULL; - } - - read_unlock_bh(&nf_conntrack_lock); - - return helper; -} -EXPORT_SYMBOL_GPL(nf_ct_helper_find_get); - -void nf_ct_helper_put(struct nf_conntrack_helper *helper) -{ - module_put(helper->me); -} -EXPORT_SYMBOL_GPL(nf_ct_helper_put); +EXPORT_SYMBOL_GPL(__nf_ct_helper_find); struct nf_conntrack_helper * __nf_conntrack_helper_find_byname(const char *name) @@ -99,7 +71,7 @@ __nf_conntrack_helper_find_byname(const char *name) unsigned int i; for (i = 0; i < nf_ct_helper_hsize; i++) { - hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) { + hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) { if (!strcmp(h->name, name)) return h; } @@ -140,10 +112,10 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me) BUG_ON(me->timeout == 0); - write_lock_bh(&nf_conntrack_lock); - hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]); + mutex_lock(&nf_ct_helper_mutex); + hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]); nf_ct_helper_count++; - write_unlock_bh(&nf_conntrack_lock); + mutex_unlock(&nf_ct_helper_mutex); return 0; } @@ -156,10 +128,17 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) struct hlist_node *n, *next; unsigned int i; - /* Need write lock here, to delete helper. */ - write_lock_bh(&nf_conntrack_lock); - hlist_del(&me->hnode); + mutex_lock(&nf_ct_helper_mutex); + hlist_del_rcu(&me->hnode); nf_ct_helper_count--; + mutex_unlock(&nf_ct_helper_mutex); + + /* Make sure every nothing is still using the helper unless its a + * connection in the hash. + */ + synchronize_rcu(); + + write_lock_bh(&nf_conntrack_lock); /* Get rid of expectations */ for (i = 0; i < nf_ct_expect_hsize; i++) { @@ -182,9 +161,6 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) unhelp(h, me); } write_unlock_bh(&nf_conntrack_lock); - - /* Someone could be still looking at the helper in a bh. */ - synchronize_net(); } EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index bdae2924d425..b6c0935e09df 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1167,11 +1167,12 @@ ctnetlink_create_conntrack(struct nlattr *cda[], ct->mark = ntohl(nla_get_be32(cda[CTA_MARK])); #endif - helper = nf_ct_helper_find_get(rtuple); + rcu_read_lock(); + helper = __nf_ct_helper_find(rtuple); if (helper) { help = nf_ct_helper_ext_add(ct, GFP_KERNEL); if (help == NULL) { - nf_ct_helper_put(helper); + rcu_read_unlock(); err = -ENOMEM; goto err; } @@ -1187,9 +1188,7 @@ ctnetlink_create_conntrack(struct nlattr *cda[], add_timer(&ct->timeout); nf_conntrack_hash_insert(ct); - - if (helper) - nf_ct_helper_put(helper); + rcu_read_unlock(); return 0; -- 2.39.5