| /* L3/L4 protocol support for nf_conntrack. */ |
| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/netfilter.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/mutex.h> |
| #include <linux/vmalloc.h> |
| #include <linux/stddef.h> |
| #include <linux/err.h> |
| #include <linux/percpu.h> |
| #include <linux/notifier.h> |
| #include <linux/kernel.h> |
| #include <linux/netdevice.h> |
| #include <linux/rtnetlink.h> |
| |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_l3proto.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| |
| static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly; |
| struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly; |
| EXPORT_SYMBOL_GPL(nf_ct_l3protos); |
| |
| static DEFINE_MUTEX(nf_ct_proto_mutex); |
| |
| #ifdef CONFIG_SYSCTL |
| static int |
| nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path, |
| struct ctl_table *table, unsigned int *users) |
| { |
| if (*header == NULL) { |
| *header = register_sysctl_paths(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; |
| |
| unregister_sysctl_table(*header); |
| *header = NULL; |
| } |
| #endif |
| |
| struct nf_conntrack_l4proto * |
| __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) |
| { |
| if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) |
| return &nf_conntrack_l4proto_generic; |
| |
| return rcu_dereference(nf_ct_protos[l3proto][l4proto]); |
| } |
| EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find); |
| |
| /* this is guaranteed to always return a valid protocol helper, since |
| * it falls back to generic_protocol */ |
| struct nf_conntrack_l3proto * |
| nf_ct_l3proto_find_get(u_int16_t l3proto) |
| { |
| struct nf_conntrack_l3proto *p; |
| |
| rcu_read_lock(); |
| p = __nf_ct_l3proto_find(l3proto); |
| if (!try_module_get(p->me)) |
| p = &nf_conntrack_l3proto_generic; |
| rcu_read_unlock(); |
| |
| return p; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get); |
| |
| void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p) |
| { |
| module_put(p->me); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_l3proto_put); |
| |
| int |
| nf_ct_l3proto_try_module_get(unsigned short l3proto) |
| { |
| int ret; |
| int retried = 0; |
| struct nf_conntrack_l3proto *p; |
| |
| retry: p = nf_ct_l3proto_find_get(l3proto); |
| if (p == &nf_conntrack_l3proto_generic) { |
| if (!retried) { |
| ret = request_module("nf_conntrack-%d", l3proto); |
| if (!ret) { |
| retried = 1; |
| goto retry; |
| } |
| } |
| |
| return -EPROTOTYPE; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get); |
| |
| void nf_ct_l3proto_module_put(unsigned short l3proto) |
| { |
| struct nf_conntrack_l3proto *p; |
| |
| /* rcu_read_lock not necessary since the caller holds a reference, but |
| * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find() |
| */ |
| rcu_read_lock(); |
| p = __nf_ct_l3proto_find(l3proto); |
| module_put(p->me); |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); |
| |
| static int kill_l3proto(struct nf_conn *i, void *data) |
| { |
| return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto; |
| } |
| |
| static int kill_l4proto(struct nf_conn *i, void *data) |
| { |
| struct nf_conntrack_l4proto *l4proto; |
| l4proto = (struct nf_conntrack_l4proto *)data; |
| return nf_ct_protonum(i) == l4proto->l4proto && |
| nf_ct_l3num(i) == l4proto->l3proto; |
| } |
| |
| static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto) |
| { |
| int err = 0; |
| |
| #ifdef CONFIG_SYSCTL |
| if (l3proto->ctl_table != NULL) { |
| err = nf_ct_register_sysctl(&l3proto->ctl_table_header, |
| l3proto->ctl_table_path, |
| l3proto->ctl_table, NULL); |
| } |
| #endif |
| return err; |
| } |
| |
| static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto) |
| { |
| #ifdef CONFIG_SYSCTL |
| if (l3proto->ctl_table_header != NULL) |
| nf_ct_unregister_sysctl(&l3proto->ctl_table_header, |
| l3proto->ctl_table, NULL); |
| #endif |
| } |
| |
| int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto) |
| { |
| int ret = 0; |
| struct nf_conntrack_l3proto *old; |
| |
| if (proto->l3proto >= AF_MAX) |
| return -EBUSY; |
| |
| if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size) |
| return -EINVAL; |
| |
| mutex_lock(&nf_ct_proto_mutex); |
| old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], |
| lockdep_is_held(&nf_ct_proto_mutex)); |
| if (old != &nf_conntrack_l3proto_generic) { |
| ret = -EBUSY; |
| goto out_unlock; |
| } |
| |
| ret = nf_ct_l3proto_register_sysctl(proto); |
| if (ret < 0) |
| goto out_unlock; |
| |
| if (proto->nlattr_tuple_size) |
| proto->nla_size = 3 * proto->nlattr_tuple_size(); |
| |
| rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto); |
| |
| out_unlock: |
| mutex_unlock(&nf_ct_proto_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register); |
| |
| void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto) |
| { |
| struct net *net; |
| |
| BUG_ON(proto->l3proto >= AF_MAX); |
| |
| mutex_lock(&nf_ct_proto_mutex); |
| BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto], |
| lockdep_is_held(&nf_ct_proto_mutex) |
| ) != proto); |
| rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], |
| &nf_conntrack_l3proto_generic); |
| nf_ct_l3proto_unregister_sysctl(proto); |
| mutex_unlock(&nf_ct_proto_mutex); |
| |
| synchronize_rcu(); |
| |
| /* Remove all contrack entries for this protocol */ |
| rtnl_lock(); |
| for_each_net(net) |
| nf_ct_iterate_cleanup(net, kill_l3proto, proto); |
| rtnl_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister); |
| |
| static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto) |
| { |
| int err = 0; |
| |
| #ifdef CONFIG_SYSCTL |
| 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); |
| if (err < 0) |
| goto out; |
| } |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| if (l4proto->ctl_compat_table != NULL) { |
| err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header, |
| nf_net_ipv4_netfilter_sysctl_path, |
| l4proto->ctl_compat_table, NULL); |
| if (err == 0) |
| goto out; |
| nf_ct_unregister_sysctl(l4proto->ctl_table_header, |
| l4proto->ctl_table, |
| l4proto->ctl_table_users); |
| } |
| #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| out: |
| #endif /* CONFIG_SYSCTL */ |
| return err; |
| } |
| |
| static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto) |
| { |
| #ifdef CONFIG_SYSCTL |
| 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); |
| #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT |
| if (l4proto->ctl_compat_table_header != NULL) |
| nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header, |
| l4proto->ctl_compat_table, NULL); |
| #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| #endif /* CONFIG_SYSCTL */ |
| } |
| |
| /* FIXME: Allow NULL functions and sub in pointers to generic for |
| them. --RR */ |
| int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto) |
| { |
| int ret = 0; |
| |
| if (l4proto->l3proto >= PF_MAX) |
| return -EBUSY; |
| |
| if ((l4proto->to_nlattr && !l4proto->nlattr_size) |
| || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size)) |
| return -EINVAL; |
| |
| mutex_lock(&nf_ct_proto_mutex); |
| if (!nf_ct_protos[l4proto->l3proto]) { |
| /* l3proto may be loaded latter. */ |
| struct nf_conntrack_l4proto __rcu **proto_array; |
| int i; |
| |
| proto_array = kmalloc(MAX_NF_CT_PROTO * |
| sizeof(struct nf_conntrack_l4proto *), |
| GFP_KERNEL); |
| if (proto_array == NULL) { |
| ret = -ENOMEM; |
| goto out_unlock; |
| } |
| |
| for (i = 0; i < MAX_NF_CT_PROTO; i++) |
| RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic); |
| |
| /* Before making proto_array visible to lockless readers, |
| * we must make sure its content is committed to memory. |
| */ |
| smp_wmb(); |
| |
| nf_ct_protos[l4proto->l3proto] = proto_array; |
| } else if (rcu_dereference_protected( |
| nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| lockdep_is_held(&nf_ct_proto_mutex) |
| ) != &nf_conntrack_l4proto_generic) { |
| ret = -EBUSY; |
| goto out_unlock; |
| } |
| |
| ret = nf_ct_l4proto_register_sysctl(l4proto); |
| if (ret < 0) |
| goto out_unlock; |
| |
| l4proto->nla_size = 0; |
| if (l4proto->nlattr_size) |
| l4proto->nla_size += l4proto->nlattr_size(); |
| if (l4proto->nlattr_tuple_size) |
| l4proto->nla_size += 3 * l4proto->nlattr_tuple_size(); |
| |
| rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| l4proto); |
| |
| out_unlock: |
| mutex_unlock(&nf_ct_proto_mutex); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register); |
| |
| void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) |
| { |
| struct net *net; |
| |
| BUG_ON(l4proto->l3proto >= PF_MAX); |
| |
| mutex_lock(&nf_ct_proto_mutex); |
| BUG_ON(rcu_dereference_protected( |
| nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| lockdep_is_held(&nf_ct_proto_mutex) |
| ) != l4proto); |
| rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], |
| &nf_conntrack_l4proto_generic); |
| nf_ct_l4proto_unregister_sysctl(l4proto); |
| mutex_unlock(&nf_ct_proto_mutex); |
| |
| synchronize_rcu(); |
| |
| /* Remove all contrack entries for this protocol */ |
| rtnl_lock(); |
| for_each_net(net) |
| nf_ct_iterate_cleanup(net, kill_l4proto, l4proto); |
| rtnl_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister); |
| |
| int nf_conntrack_proto_init(void) |
| { |
| unsigned int i; |
| int err; |
| |
| err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic); |
| if (err < 0) |
| return err; |
| |
| for (i = 0; i < AF_MAX; i++) |
| rcu_assign_pointer(nf_ct_l3protos[i], |
| &nf_conntrack_l3proto_generic); |
| return 0; |
| } |
| |
| void nf_conntrack_proto_fini(void) |
| { |
| unsigned int i; |
| |
| nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic); |
| |
| /* free l3proto protocol tables */ |
| for (i = 0; i < PF_MAX; i++) |
| kfree(nf_ct_protos[i]); |
| } |