From d62f9ed4a490309bd9e5df0b42ba5d096e7b5902 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Wed, 29 Nov 2006 02:35:17 +0100 Subject: [PATCH] [NETFILTER]: nf_conntrack: automatic sysctl registation for conntrack protocols Add helper functions for sysctl registration with optional instantiating of common path elements (like net/netfilter) and use it for support for automatic registation of conntrack protocol sysctls. Signed-off-by: Patrick McHardy --- include/linux/netfilter.h | 10 ++ include/net/netfilter/nf_conntrack_l3proto.h | 6 + include/net/netfilter/nf_conntrack_l4proto.h | 6 + net/netfilter/Makefile | 1 + net/netfilter/nf_conntrack_proto.c | 102 ++++++++++++++ net/netfilter/nf_sysctl.c | 134 +++++++++++++++++++ 6 files changed, 259 insertions(+) create mode 100644 net/netfilter/nf_sysctl.c diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 6ab5e2d6133e..f6f3fcbd70ed 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -117,6 +117,16 @@ void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); int nf_register_sockopt(struct nf_sockopt_ops *reg); void nf_unregister_sockopt(struct nf_sockopt_ops *reg); +#ifdef CONFIG_SYSCTL +/* Sysctl registration */ +struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path, + struct ctl_table *table); +void nf_unregister_sysctl_table(struct ctl_table_header *header, + struct ctl_table *table); +extern struct ctl_table nf_net_netfilter_sysctl_path[]; +extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[]; +#endif /* CONFIG_SYSCTL */ + extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS]; /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will diff --git a/include/net/netfilter/nf_conntrack_l3proto.h b/include/net/netfilter/nf_conntrack_l3proto.h index 6364df059422..664ddcffe00d 100644 --- a/include/net/netfilter/nf_conntrack_l3proto.h +++ b/include/net/netfilter/nf_conntrack_l3proto.h @@ -75,6 +75,12 @@ struct nf_conntrack_l3proto int (*nfattr_to_tuple)(struct nfattr *tb[], struct nf_conntrack_tuple *t); +#ifdef CONFIG_SYSCTL + struct ctl_table_header *ctl_table_header; + struct ctl_table *ctl_table_path; + struct ctl_table *ctl_table; +#endif /* CONFIG_SYSCTL */ + /* Module (if any) which this is connected to. */ struct module *me; }; diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h index c22804aa227e..fe1e8fa30d2f 100644 --- a/include/net/netfilter/nf_conntrack_l4proto.h +++ b/include/net/netfilter/nf_conntrack_l4proto.h @@ -76,6 +76,12 @@ struct nf_conntrack_l4proto int (*nfattr_to_tuple)(struct nfattr *tb[], struct nf_conntrack_tuple *t); +#ifdef CONFIG_SYSCTL + struct ctl_table_header **ctl_table_header; + struct ctl_table *ctl_table; + unsigned int *ctl_table_users; +#endif /* CONFIG_SYSCTL */ + /* Module (if any) which this is connected to. */ struct module *me; }; diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 627105df1040..84d529ded952 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -4,6 +4,7 @@ nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_exp nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o obj-$(CONFIG_NETFILTER) = netfilter.o +obj-$(CONFIG_SYSCTL) += nf_sysctl.o obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o obj-$(CONFIG_NETFILTER_NETLINK_QUEUE) += nfnetlink_queue.o diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c index a6a3b1ddd00d..941b5c3754af 100644 --- a/net/netfilter/nf_conntrack_proto.c +++ b/net/netfilter/nf_conntrack_proto.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -30,6 +31,34 @@ struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly; struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly; +#ifdef CONFIG_SYSCTL +static DEFINE_MUTEX(nf_ct_proto_sysctl_mutex); + +static int +nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_table *path, + struct ctl_table *table, unsigned int *users) +{ + if (*header == NULL) { + *header = nf_register_sysctl_table(path, table); + if (*header == NULL) + return -ENOMEM; + } + if (users != NULL) + (*users)++; + return 0; +} + +static void +nf_ct_unregister_sysctl(struct ctl_table_header **header, + struct ctl_table *table, unsigned int *users) +{ + if (users != NULL && --*users > 0) + return; + nf_unregister_sysctl_table(*header, table); + *header = NULL; +} +#endif + struct nf_conntrack_l4proto * __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) { @@ -124,6 +153,33 @@ static int kill_l4proto(struct nf_conn *i, void *data) l4proto->l3proto); } +static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto) +{ + int err = 0; + +#ifdef CONFIG_SYSCTL + mutex_lock(&nf_ct_proto_sysctl_mutex); + if (l3proto->ctl_table != NULL) { + err = nf_ct_register_sysctl(&l3proto->ctl_table_header, + l3proto->ctl_table_path, + l3proto->ctl_table, NULL); + } + mutex_unlock(&nf_ct_proto_sysctl_mutex); +#endif + return err; +} + +static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto) +{ +#ifdef CONFIG_SYSCTL + mutex_lock(&nf_ct_proto_sysctl_mutex); + if (l3proto->ctl_table_header != NULL) + nf_ct_unregister_sysctl(&l3proto->ctl_table_header, + l3proto->ctl_table, NULL); + mutex_unlock(&nf_ct_proto_sysctl_mutex); +#endif +} + int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto) { int ret = 0; @@ -139,6 +195,12 @@ int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto) goto out_unlock; } nf_ct_l3protos[proto->l3proto] = proto; + write_unlock_bh(&nf_conntrack_lock); + + ret = nf_ct_l3proto_register_sysctl(proto); + if (ret < 0) + nf_conntrack_l3proto_unregister(proto); + return ret; out_unlock: write_unlock_bh(&nf_conntrack_lock); @@ -165,6 +227,8 @@ int nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto) nf_ct_l3protos[proto->l3proto] = &nf_conntrack_l3proto_generic; write_unlock_bh(&nf_conntrack_lock); + nf_ct_l3proto_unregister_sysctl(proto); + /* Somebody could be still looking at the proto in bh. */ synchronize_net(); @@ -175,6 +239,36 @@ int nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto) return ret; } +static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto) +{ + int err = 0; + +#ifdef CONFIG_SYSCTL + mutex_lock(&nf_ct_proto_sysctl_mutex); + if (l4proto->ctl_table != NULL) { + err = nf_ct_register_sysctl(l4proto->ctl_table_header, + nf_net_netfilter_sysctl_path, + l4proto->ctl_table, + l4proto->ctl_table_users); + } + mutex_unlock(&nf_ct_proto_sysctl_mutex); +#endif + return err; +} + +static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto) +{ +#ifdef CONFIG_SYSCTL + mutex_lock(&nf_ct_proto_sysctl_mutex); + if (l4proto->ctl_table_header != NULL && + *l4proto->ctl_table_header != NULL) + nf_ct_unregister_sysctl(l4proto->ctl_table_header, + l4proto->ctl_table, + l4proto->ctl_table_users); + mutex_unlock(&nf_ct_proto_sysctl_mutex); +#endif +} + /* FIXME: Allow NULL functions and sub in pointers to generic for them. --RR */ int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto) @@ -230,6 +324,12 @@ int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto) } nf_ct_protos[l4proto->l3proto][l4proto->l4proto] = l4proto; + write_unlock_bh(&nf_conntrack_lock); + + ret = nf_ct_l4proto_register_sysctl(l4proto); + if (ret < 0) + nf_conntrack_l4proto_unregister(l4proto); + return ret; out_unlock: write_unlock_bh(&nf_conntrack_lock); @@ -257,6 +357,8 @@ int nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) = &nf_conntrack_l4proto_generic; write_unlock_bh(&nf_conntrack_lock); + nf_ct_l4proto_unregister_sysctl(l4proto); + /* Somebody could be still looking at the proto in bh. */ synchronize_net(); diff --git a/net/netfilter/nf_sysctl.c b/net/netfilter/nf_sysctl.c new file mode 100644 index 000000000000..06ddddb2911f --- /dev/null +++ b/net/netfilter/nf_sysctl.c @@ -0,0 +1,134 @@ +/* nf_sysctl.c netfilter sysctl registration/unregistation + * + * Copyright (c) 2006 Patrick McHardy + */ +#include +#include +#include +#include + +static void +path_free(struct ctl_table *path, struct ctl_table *table) +{ + struct ctl_table *t, *next; + + for (t = path; t != NULL && t != table; t = next) { + next = t->child; + kfree(t); + } +} + +static struct ctl_table * +path_dup(struct ctl_table *path, struct ctl_table *table) +{ + struct ctl_table *t, *last = NULL, *tmp; + + for (t = path; t != NULL; t = t->child) { + /* twice the size since path elements are terminated by an + * empty element */ + tmp = kmemdup(t, 2 * sizeof(*t), GFP_KERNEL); + if (tmp == NULL) { + if (last != NULL) + path_free(path, table); + return NULL; + } + + if (last != NULL) + last->child = tmp; + else + path = tmp; + last = tmp; + } + + if (last != NULL) + last->child = table; + else + path = table; + + return path; +} + +struct ctl_table_header * +nf_register_sysctl_table(struct ctl_table *path, struct ctl_table *table) +{ + struct ctl_table_header *header; + + path = path_dup(path, table); + if (path == NULL) + return NULL; + header = register_sysctl_table(path, 0); + if (header == NULL) + path_free(path, table); + return header; +} +EXPORT_SYMBOL_GPL(nf_register_sysctl_table); + +void +nf_unregister_sysctl_table(struct ctl_table_header *header, + struct ctl_table *table) +{ + struct ctl_table *path = header->ctl_table; + + unregister_sysctl_table(header); + path_free(path, table); +} +EXPORT_SYMBOL_GPL(nf_unregister_sysctl_table); + +/* net/netfilter */ +static struct ctl_table nf_net_netfilter_table[] = { + { + .ctl_name = NET_NETFILTER, + .procname = "netfilter", + .mode = 0555, + }, + { + .ctl_name = 0 + } +}; +struct ctl_table nf_net_netfilter_sysctl_path[] = { + { + .ctl_name = CTL_NET, + .procname = "net", + .mode = 0555, + .child = nf_net_netfilter_table, + }, + { + .ctl_name = 0 + } +}; +EXPORT_SYMBOL_GPL(nf_net_netfilter_sysctl_path); + +/* net/ipv4/netfilter */ +static struct ctl_table nf_net_ipv4_netfilter_table[] = { + { + .ctl_name = NET_IPV4_NETFILTER, + .procname = "netfilter", + .mode = 0555, + }, + { + .ctl_name = 0 + } +}; +static struct ctl_table nf_net_ipv4_table[] = { + { + .ctl_name = NET_IPV4, + .procname = "ipv4", + .mode = 0555, + .child = nf_net_ipv4_netfilter_table, + }, + { + .ctl_name = 0 + } +}; +struct ctl_table nf_net_ipv4_netfilter_sysctl_path[] = { + { + .ctl_name = CTL_NET, + .procname = "net", + .mode = 0555, + .child = nf_net_ipv4_table, + }, + { + .ctl_name = 0 + } +}; +EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);