From fa34fff5e69cc56eecf26754c9b57403899ebd0d Mon Sep 17 00:00:00 2001 From: Gao feng Date: Thu, 21 Jun 2012 04:36:41 +0000 Subject: [PATCH] netfilter: nf_conntrack: use l4proto->users as refcount for per-net data Currently, nf_proto_net's l4proto->users meaning is quite confusing since it depends on the compilation tweaks. To resolve this, we cleanup this code to regard it as the refcount for l4proto's per-net data, since there may be two l4protos use the same per-net data. Thus, we increment pn->users when nf_conntrack_l4proto_register successfully, and decrement it for nf_conntrack_l4_unregister case. The users refcnt is not required form layer 3 protocol trackers. Signed-off-by: Gao feng Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_proto.c | 76 ++++++++++++++++++------------ 1 file changed, 46 insertions(+), 30 deletions(-) diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c index 9d6b6ab193a9..63612e6d7238 100644 --- a/net/netfilter/nf_conntrack_proto.c +++ b/net/netfilter/nf_conntrack_proto.c @@ -39,16 +39,13 @@ static int nf_ct_register_sysctl(struct net *net, struct ctl_table_header **header, const char *path, - struct ctl_table *table, - unsigned int *users) + struct ctl_table *table) { if (*header == NULL) { *header = register_net_sysctl(net, path, table); if (*header == NULL) return -ENOMEM; } - if (users != NULL) - (*users)++; return 0; } @@ -56,9 +53,9 @@ nf_ct_register_sysctl(struct net *net, static void nf_ct_unregister_sysctl(struct ctl_table_header **header, struct ctl_table **table, - unsigned int *users) + unsigned int users) { - if (users != NULL && --*users > 0) + if (users > 0) return; unregister_net_sysctl_table(*header); @@ -191,8 +188,7 @@ static int nf_ct_l3proto_register_sysctl(struct net *net, err = nf_ct_register_sysctl(net, &in->ctl_table_header, l3proto->ctl_table_path, - in->ctl_table, - NULL); + in->ctl_table); if (err < 0) { kfree(in->ctl_table); in->ctl_table = NULL; @@ -213,7 +209,7 @@ static void nf_ct_l3proto_unregister_sysctl(struct net *net, if (in->ctl_table_header != NULL) nf_ct_unregister_sysctl(&in->ctl_table_header, &in->ctl_table, - NULL); + 0); #endif } @@ -329,20 +325,17 @@ static struct nf_proto_net *nf_ct_l4proto_net(struct net *net, static int nf_ct_l4proto_register_sysctl(struct net *net, + struct nf_proto_net *pn, struct nf_conntrack_l4proto *l4proto) { int err = 0; - struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto); - if (pn == NULL) - return 0; #ifdef CONFIG_SYSCTL if (pn->ctl_table != NULL) { err = nf_ct_register_sysctl(net, &pn->ctl_table_header, "net/netfilter", - pn->ctl_table, - &pn->users); + pn->ctl_table); if (err < 0) { if (!pn->users) { kfree(pn->ctl_table); @@ -356,15 +349,14 @@ int nf_ct_l4proto_register_sysctl(struct net *net, err = nf_ct_register_sysctl(net, &pn->ctl_compat_header, "net/ipv4/netfilter", - pn->ctl_compat_table, - NULL); + pn->ctl_compat_table); if (err == 0) goto out; nf_ct_kfree_compat_sysctl_table(pn); nf_ct_unregister_sysctl(&pn->ctl_table_header, &pn->ctl_table, - &pn->users); + pn->users); } #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ out: @@ -374,25 +366,21 @@ out: static void nf_ct_l4proto_unregister_sysctl(struct net *net, + struct nf_proto_net *pn, struct nf_conntrack_l4proto *l4proto) { - struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto); - if (pn == NULL) - return; #ifdef CONFIG_SYSCTL if (pn->ctl_table_header != NULL) nf_ct_unregister_sysctl(&pn->ctl_table_header, &pn->ctl_table, - &pn->users); + pn->users); #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_header != NULL) nf_ct_unregister_sysctl(&pn->ctl_compat_header, &pn->ctl_compat_table, - NULL); + 0); #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ -#else - pn->users--; #endif /* CONFIG_SYSCTL */ } @@ -458,23 +446,32 @@ int nf_conntrack_l4proto_register(struct net *net, struct nf_conntrack_l4proto *l4proto) { int ret = 0; + struct nf_proto_net *pn = NULL; if (l4proto->init_net) { ret = l4proto->init_net(net, l4proto->l3proto); if (ret < 0) - return ret; + goto out; } - ret = nf_ct_l4proto_register_sysctl(net, l4proto); + pn = nf_ct_l4proto_net(net, l4proto); + if (pn == NULL) + goto out; + + ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto); if (ret < 0) - return ret; + goto out; if (net == &init_net) { ret = nf_conntrack_l4proto_register_net(l4proto); - if (ret < 0) - nf_ct_l4proto_unregister_sysctl(net, l4proto); + if (ret < 0) { + nf_ct_l4proto_unregister_sysctl(net, pn, l4proto); + goto out; + } } + pn->users++; +out: return ret; } EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register); @@ -499,10 +496,18 @@ nf_conntrack_l4proto_unregister_net(struct nf_conntrack_l4proto *l4proto) void nf_conntrack_l4proto_unregister(struct net *net, struct nf_conntrack_l4proto *l4proto) { + struct nf_proto_net *pn = NULL; + if (net == &init_net) nf_conntrack_l4proto_unregister_net(l4proto); - nf_ct_l4proto_unregister_sysctl(net, l4proto); + pn = nf_ct_l4proto_net(net, l4proto); + if (pn == NULL) + return; + + pn->users--; + nf_ct_l4proto_unregister_sysctl(net, pn, l4proto); + /* Remove all contrack entries for this protocol */ rtnl_lock(); nf_ct_iterate_cleanup(net, kill_l4proto, l4proto); @@ -514,11 +519,15 @@ int nf_conntrack_proto_init(struct net *net) { unsigned int i; int err; + struct nf_proto_net *pn = nf_ct_l4proto_net(net, + &nf_conntrack_l4proto_generic); + err = nf_conntrack_l4proto_generic.init_net(net, nf_conntrack_l4proto_generic.l3proto); if (err < 0) return err; err = nf_ct_l4proto_register_sysctl(net, + pn, &nf_conntrack_l4proto_generic); if (err < 0) return err; @@ -528,13 +537,20 @@ int nf_conntrack_proto_init(struct net *net) rcu_assign_pointer(nf_ct_l3protos[i], &nf_conntrack_l3proto_generic); } + + pn->users++; return 0; } void nf_conntrack_proto_fini(struct net *net) { unsigned int i; + struct nf_proto_net *pn = nf_ct_l4proto_net(net, + &nf_conntrack_l4proto_generic); + + pn->users--; nf_ct_l4proto_unregister_sysctl(net, + pn, &nf_conntrack_l4proto_generic); if (net == &init_net) { /* free l3proto protocol tables */