From af4610c39589d839551da104f7da342d86f23ea0 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 25 Feb 2016 10:08:38 +0100 Subject: [PATCH] netfilter: don't call hooks unless needed With the previous patches in place, a netns nf_hook_list might be empty, even if e.g. init_net performs filtering. Thus change nf_hook_thresh to check the hook_list as well before initializing hook_state and calling nf_hook_slow(). We still make use of static keys; if no netfilter modules are loaded list is guaranteed to be empty. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter.h | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 0ad556726181..9230f9aee896 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -141,22 +141,6 @@ void nf_unregister_sockopt(struct nf_sockopt_ops *reg); #ifdef HAVE_JUMP_LABEL extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; - -static inline bool nf_hook_list_active(struct list_head *hook_list, - u_int8_t pf, unsigned int hook) -{ - if (__builtin_constant_p(pf) && - __builtin_constant_p(hook)) - return static_key_false(&nf_hooks_needed[pf][hook]); - - return !list_empty(hook_list); -} -#else -static inline bool nf_hook_list_active(struct list_head *hook_list, - u_int8_t pf, unsigned int hook) -{ - return !list_empty(hook_list); -} #endif int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state); @@ -177,9 +161,18 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, int (*okfn)(struct net *, struct sock *, struct sk_buff *), int thresh) { - struct list_head *hook_list = &net->nf.hooks[pf][hook]; + struct list_head *hook_list; + +#ifdef HAVE_JUMP_LABEL + if (__builtin_constant_p(pf) && + __builtin_constant_p(hook) && + !static_key_false(&nf_hooks_needed[pf][hook])) + return 1; +#endif + + hook_list = &net->nf.hooks[pf][hook]; - if (nf_hook_list_active(hook_list, pf, hook)) { + if (!list_empty(hook_list)) { struct nf_hook_state state; nf_hook_state_init(&state, hook_list, hook, thresh, -- 2.20.1