From 342b7e3c8a3c84252799c4ac4d9a604b8903d2b4 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sat, 7 Jul 2007 22:39:16 -0700 Subject: [PATCH] [NETFILTER]: xt_helper: use RCU The ->helper pointer is protected by RCU, no need to take nf_conntrack_lock. Also remove excessive debugging. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/netfilter/xt_helper.c | 31 ++++++++----------------------- 1 file changed, 8 insertions(+), 23 deletions(-) diff --git a/net/netfilter/xt_helper.c b/net/netfilter/xt_helper.c index d03acb032cc8..0a1f4c6bcdef 100644 --- a/net/netfilter/xt_helper.c +++ b/net/netfilter/xt_helper.c @@ -22,11 +22,6 @@ MODULE_DESCRIPTION("iptables helper match module"); MODULE_ALIAS("ipt_helper"); MODULE_ALIAS("ip6t_helper"); -#if 0 -#define DEBUGP printk -#else -#define DEBUGP(format, args...) -#endif static bool match(const struct sk_buff *skb, @@ -41,38 +36,28 @@ match(const struct sk_buff *skb, const struct xt_helper_info *info = matchinfo; const struct nf_conn *ct; const struct nf_conn_help *master_help; + const struct nf_conntrack_helper *helper; enum ip_conntrack_info ctinfo; bool ret = info->invert; ct = nf_ct_get(skb, &ctinfo); - if (!ct) { - DEBUGP("xt_helper: Eek! invalid conntrack?\n"); + if (!ct || !ct->master) return ret; - } - if (!ct->master) { - DEBUGP("xt_helper: conntrack %p has no master\n", ct); - return ret; - } - - read_lock_bh(&nf_conntrack_lock); master_help = nfct_help(ct->master); - if (!master_help || !master_help->helper) { - DEBUGP("xt_helper: master ct %p has no helper\n", - exp->expectant); - goto out_unlock; - } + if (!master_help) + return ret; - DEBUGP("master's name = %s , info->name = %s\n", - ct->master->helper->name, info->name); + /* rcu_read_lock()ed by nf_hook_slow */ + helper = rcu_dereference(master_help->helper); + if (!helper) + return ret; if (info->name[0] == '\0') ret = !ret; else ret ^= !strncmp(master_help->helper->name, info->name, strlen(master_help->helper->name)); -out_unlock: - read_unlock_bh(&nf_conntrack_lock); return ret; }