From 7c9664351980aaa6a4b8837a314360b3a4ad382a Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 5 Jul 2016 12:07:23 +0200 Subject: [PATCH] netfilter: move nat hlist_head to nf_conn The nat extension structure is 32bytes in size on x86_64: struct nf_conn_nat { struct hlist_node bysource; /* 0 16 */ struct nf_conn * ct; /* 16 8 */ union nf_conntrack_nat_help help; /* 24 4 */ int masq_index; /* 28 4 */ /* size: 32, cachelines: 1, members: 4 */ /* last cacheline: 32 bytes */ }; The hlist is needed to quickly check for possible tuple collisions when installing a new nat binding. Storing this in the extension area has two drawbacks: 1. We need ct backpointer to get the conntrack struct from the extension. 2. When reallocation of extension area occurs we need to fixup the bysource hash head via hlist_replace_rcu. We can avoid both by placing the hlist_head in nf_conn and place nf_conn in the bysource hash rather than the extenstion. We can also remove the ->move support; no other extension needs it. Moving the entire nat extension into nf_conn would be possible as well but then we have to add yet another callback for deletion from the bysource hash table rather than just using nat extension ->destroy hook for this. nf_conn size doesn't increase due to aligment, followup patch replaces hlist_node with single pointer. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack.h | 3 +++ include/net/netfilter/nf_conntrack_extend.h | 3 --- include/net/netfilter/nf_nat.h | 2 -- net/netfilter/nf_conntrack_extend.c | 15 ++----------- net/netfilter/nf_nat_core.c | 33 ++++++----------------------- 5 files changed, 12 insertions(+), 44 deletions(-) diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index 2a5133e..e5135d8 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -117,6 +117,9 @@ struct nf_conn { /* Extensions */ struct nf_ct_ext *ext; +#if IS_ENABLED(CONFIG_NF_NAT) + struct hlist_node nat_bysource; +#endif /* Storage reserved for other modules, must be the last member */ union nf_conntrack_proto proto; }; diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index b925395..1c3035d 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -99,9 +99,6 @@ void *__nf_ct_ext_add_length(struct nf_conn *ct, enum nf_ct_ext_id id, struct nf_ct_ext_type { /* Destroys relationships (can be NULL). */ void (*destroy)(struct nf_conn *ct); - /* Called when realloacted (can be NULL). - Contents has already been moved. */ - void (*move)(void *new, void *old); enum nf_ct_ext_id id; diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h index 344b1ab..02515f7 100644 --- a/include/net/netfilter/nf_nat.h +++ b/include/net/netfilter/nf_nat.h @@ -29,8 +29,6 @@ struct nf_conn; /* The structure embedded in the conntrack structure. */ struct nf_conn_nat { - struct hlist_node bysource; - struct nf_conn *ct; union nf_conntrack_nat_help help; #if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV4) || \ IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV6) diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c index 1a95459..02bcf00 100644 --- a/net/netfilter/nf_conntrack_extend.c +++ b/net/netfilter/nf_conntrack_extend.c @@ -73,7 +73,7 @@ void *__nf_ct_ext_add_length(struct nf_conn *ct, enum nf_ct_ext_id id, size_t var_alloc_len, gfp_t gfp) { struct nf_ct_ext *old, *new; - int i, newlen, newoff; + int newlen, newoff; struct nf_ct_ext_type *t; /* Conntrack must not be confirmed to avoid races on reallocation. */ @@ -99,19 +99,8 @@ void *__nf_ct_ext_add_length(struct nf_conn *ct, enum nf_ct_ext_id id, return NULL; if (new != old) { - for (i = 0; i < NF_CT_EXT_NUM; i++) { - if (!__nf_ct_ext_exist(old, i)) - continue; - - rcu_read_lock(); - t = rcu_dereference(nf_ct_ext_types[i]); - if (t && t->move) - t->move((void *)new + new->offset[i], - (void *)old + old->offset[i]); - rcu_read_unlock(); - } kfree_rcu(old, rcu); - ct->ext = new; + rcu_assign_pointer(ct->ext, new); } new->offset[id] = newoff; diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 6877a39..6925347 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -198,11 +198,9 @@ find_appropriate_src(struct net *net, const struct nf_nat_range *range) { unsigned int h = hash_by_src(net, tuple); - const struct nf_conn_nat *nat; const struct nf_conn *ct; - hlist_for_each_entry_rcu(nat, &nf_nat_bysource[h], bysource) { - ct = nat->ct; + hlist_for_each_entry_rcu(ct, &nf_nat_bysource[h], nat_bysource) { if (same_src(ct, tuple) && net_eq(net, nf_ct_net(ct)) && nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) { @@ -435,8 +433,7 @@ nf_nat_setup_info(struct nf_conn *ct, spin_lock_bh(&nf_nat_lock); /* nf_conntrack_alter_reply might re-allocate extension aera */ nat = nfct_nat(ct); - nat->ct = ct; - hlist_add_head_rcu(&nat->bysource, + hlist_add_head_rcu(&ct->nat_bysource, &nf_nat_bysource[srchash]); spin_unlock_bh(&nf_nat_lock); } @@ -543,7 +540,7 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data) if (nf_nat_proto_remove(ct, data)) return 1; - if (!nat || !nat->ct) + if (!nat) return 0; /* This netns is being destroyed, and conntrack has nat null binding. @@ -556,9 +553,8 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data) return 1; spin_lock_bh(&nf_nat_lock); - hlist_del_rcu(&nat->bysource); + hlist_del_rcu(&ct->nat_bysource); ct->status &= ~IPS_NAT_DONE_MASK; - nat->ct = NULL; spin_unlock_bh(&nf_nat_lock); add_timer(&ct->timeout); @@ -688,27 +684,13 @@ static void nf_nat_cleanup_conntrack(struct nf_conn *ct) { struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT); - if (nat == NULL || nat->ct == NULL) + if (!nat) return; - NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE); - - spin_lock_bh(&nf_nat_lock); - hlist_del_rcu(&nat->bysource); - spin_unlock_bh(&nf_nat_lock); -} - -static void nf_nat_move_storage(void *new, void *old) -{ - struct nf_conn_nat *new_nat = new; - struct nf_conn_nat *old_nat = old; - struct nf_conn *ct = old_nat->ct; - - if (!ct || !(ct->status & IPS_SRC_NAT_DONE)) - return; + NF_CT_ASSERT(ct->status & IPS_SRC_NAT_DONE); spin_lock_bh(&nf_nat_lock); - hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); + hlist_del_rcu(&ct->nat_bysource); spin_unlock_bh(&nf_nat_lock); } @@ -716,7 +698,6 @@ static struct nf_ct_ext_type nat_extend __read_mostly = { .len = sizeof(struct nf_conn_nat), .align = __alignof__(struct nf_conn_nat), .destroy = nf_nat_cleanup_conntrack, - .move = nf_nat_move_storage, .id = NF_CT_EXT_NAT, .flags = NF_CT_EXT_F_PREALLOC, }; -- 2.7.4