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- /* 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>
- * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
- *
- * 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 <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 net *net,
- struct ctl_table_header **header,
- const char *path,
- struct ctl_table *table)
- {
- if (*header == NULL) {
- *header = register_net_sysctl(net, path, table);
- if (*header == NULL)
- return -ENOMEM;
- }
- return 0;
- }
- static void
- nf_ct_unregister_sysctl(struct ctl_table_header **header,
- struct ctl_table **table,
- unsigned int users)
- {
- if (users > 0)
- return;
- unregister_net_sysctl_table(*header);
- kfree(*table);
- *header = NULL;
- *table = 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);
- int
- nf_ct_l3proto_try_module_get(unsigned short l3proto)
- {
- int ret;
- struct nf_conntrack_l3proto *p;
- retry: p = nf_ct_l3proto_find_get(l3proto);
- if (p == &nf_conntrack_l3proto_generic) {
- ret = request_module("nf_conntrack-%d", l3proto);
- if (!ret)
- 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);
- struct nf_conntrack_l4proto *
- nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
- {
- struct nf_conntrack_l4proto *p;
- rcu_read_lock();
- p = __nf_ct_l4proto_find(l3num, l4num);
- if (!try_module_get(p->me))
- p = &nf_conntrack_l4proto_generic;
- rcu_read_unlock();
- return p;
- }
- EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
- void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
- {
- module_put(p->me);
- }
- EXPORT_SYMBOL_GPL(nf_ct_l4proto_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 struct nf_ip_net *nf_ct_l3proto_net(struct net *net,
- struct nf_conntrack_l3proto *l3proto)
- {
- if (l3proto->l3proto == PF_INET)
- return &net->ct.nf_ct_proto;
- else
- return NULL;
- }
- static int nf_ct_l3proto_register_sysctl(struct net *net,
- struct nf_conntrack_l3proto *l3proto)
- {
- int err = 0;
- struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto);
- /* nf_conntrack_l3proto_ipv6 doesn't support sysctl */
- if (in == NULL)
- return 0;
- #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
- if (in->ctl_table != NULL) {
- err = nf_ct_register_sysctl(net,
- &in->ctl_table_header,
- l3proto->ctl_table_path,
- in->ctl_table);
- if (err < 0) {
- kfree(in->ctl_table);
- in->ctl_table = NULL;
- }
- }
- #endif
- return err;
- }
- static void nf_ct_l3proto_unregister_sysctl(struct net *net,
- struct nf_conntrack_l3proto *l3proto)
- {
- struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto);
- if (in == NULL)
- return;
- #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
- if (in->ctl_table_header != NULL)
- nf_ct_unregister_sysctl(&in->ctl_table_header,
- &in->ctl_table,
- 0);
- #endif
- }
- int nf_ct_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;
- }
- 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_ct_l3proto_register);
- int nf_ct_l3proto_pernet_register(struct net *net,
- struct nf_conntrack_l3proto *proto)
- {
- int ret = 0;
- if (proto->init_net) {
- ret = proto->init_net(net);
- if (ret < 0)
- return ret;
- }
- return nf_ct_l3proto_register_sysctl(net, proto);
- }
- EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_register);
- void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto)
- {
- 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);
- mutex_unlock(&nf_ct_proto_mutex);
- synchronize_rcu();
- }
- EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister);
- void nf_ct_l3proto_pernet_unregister(struct net *net,
- struct nf_conntrack_l3proto *proto)
- {
- nf_ct_l3proto_unregister_sysctl(net, proto);
- /* Remove all contrack entries for this protocol */
- nf_ct_iterate_cleanup(net, kill_l3proto, proto, 0, 0);
- }
- EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_unregister);
- static struct nf_proto_net *nf_ct_l4proto_net(struct net *net,
- struct nf_conntrack_l4proto *l4proto)
- {
- if (l4proto->get_net_proto) {
- /* statically built-in protocols use static per-net */
- return l4proto->get_net_proto(net);
- } else if (l4proto->net_id) {
- /* ... and loadable protocols use dynamic per-net */
- return net_generic(net, *l4proto->net_id);
- }
- return NULL;
- }
- static
- int nf_ct_l4proto_register_sysctl(struct net *net,
- struct nf_proto_net *pn,
- struct nf_conntrack_l4proto *l4proto)
- {
- int err = 0;
- #ifdef CONFIG_SYSCTL
- if (pn->ctl_table != NULL) {
- err = nf_ct_register_sysctl(net,
- &pn->ctl_table_header,
- "net/netfilter",
- pn->ctl_table);
- if (err < 0) {
- if (!pn->users) {
- kfree(pn->ctl_table);
- pn->ctl_table = NULL;
- }
- }
- }
- #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
- if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_table != NULL) {
- if (err < 0) {
- nf_ct_kfree_compat_sysctl_table(pn);
- goto out;
- }
- err = nf_ct_register_sysctl(net,
- &pn->ctl_compat_header,
- "net/ipv4/netfilter",
- 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);
- }
- out:
- #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
- #endif /* CONFIG_SYSCTL */
- return err;
- }
- static
- void nf_ct_l4proto_unregister_sysctl(struct net *net,
- struct nf_proto_net *pn,
- struct nf_conntrack_l4proto *l4proto)
- {
- #ifdef CONFIG_SYSCTL
- if (pn->ctl_table_header != NULL)
- nf_ct_unregister_sysctl(&pn->ctl_table_header,
- &pn->ctl_table,
- 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,
- 0);
- #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
- #endif /* CONFIG_SYSCTL */
- }
- /* FIXME: Allow NULL functions and sub in pointers to generic for
- them. --RR */
- int nf_ct_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;
- }
- 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_ct_l4proto_register);
- int nf_ct_l4proto_pernet_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)
- goto out;
- }
- pn = nf_ct_l4proto_net(net, l4proto);
- if (pn == NULL)
- goto out;
- ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto);
- if (ret < 0)
- goto out;
- pn->users++;
- out:
- return ret;
- }
- EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register);
- void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
- {
- 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);
- mutex_unlock(&nf_ct_proto_mutex);
- synchronize_rcu();
- }
- EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister);
- void nf_ct_l4proto_pernet_unregister(struct net *net,
- struct nf_conntrack_l4proto *l4proto)
- {
- struct nf_proto_net *pn = NULL;
- 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 */
- nf_ct_iterate_cleanup(net, kill_l4proto, l4proto, 0, 0);
- }
- EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister);
- int nf_conntrack_proto_pernet_init(struct net *net)
- {
- 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;
- pn->users++;
- return 0;
- }
- void nf_conntrack_proto_pernet_fini(struct net *net)
- {
- 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);
- }
- int nf_conntrack_proto_init(void)
- {
- unsigned int i;
- 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;
- /* free l3proto protocol tables */
- for (i = 0; i < PF_MAX; i++)
- kfree(nf_ct_protos[i]);
- }
|