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![Holger Eitzenberger](/assets/img/avatar_default.png)
There is added a single callback for the l3 proto helper. The two callbacks for the l4 protos are necessary because of the general structure of a ctnetlink event, which is in short: CTA_TUPLE_ORIG <l3/l4-proto-attributes> CTA_TUPLE_REPLY <l3/l4-proto-attributes> CTA_ID ... CTA_PROTOINFO <l4-proto-attributes> CTA_TUPLE_MASTER <l3/l4-proto-attributes> Therefore the formular is size := sizeof(generic-nlas) + 3 * sizeof(tuple_nlas) + sizeof(protoinfo_nlas) Some of the NLAs are optional, e. g. CTA_TUPLE_MASTER, which is only set if it's an expected connection. But the number of optional NLAs is small enough to prevent netlink_trim() from reallocating if calculated properly. Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org> Signed-off-by: Patrick McHardy <kaber@trash.net>
365 lines
9.2 KiB
C
365 lines
9.2 KiB
C
/* L3/L4 protocol support for nf_conntrack. */
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/netfilter.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <linux/stddef.h>
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#include <linux/err.h>
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#include <linux/percpu.h>
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#include <linux/moduleparam.h>
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#include <linux/notifier.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_l3proto.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_core.h>
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static struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
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struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
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EXPORT_SYMBOL_GPL(nf_ct_l3protos);
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static DEFINE_MUTEX(nf_ct_proto_mutex);
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#ifdef CONFIG_SYSCTL
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static int
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nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path,
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struct ctl_table *table, unsigned int *users)
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{
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if (*header == NULL) {
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*header = register_sysctl_paths(path, table);
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if (*header == NULL)
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return -ENOMEM;
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}
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if (users != NULL)
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(*users)++;
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return 0;
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}
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static void
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nf_ct_unregister_sysctl(struct ctl_table_header **header,
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struct ctl_table *table, unsigned int *users)
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{
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if (users != NULL && --*users > 0)
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return;
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unregister_sysctl_table(*header);
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*header = NULL;
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}
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#endif
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struct nf_conntrack_l4proto *
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__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
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{
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if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
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return &nf_conntrack_l4proto_generic;
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return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
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}
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EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
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/* this is guaranteed to always return a valid protocol helper, since
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* it falls back to generic_protocol */
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struct nf_conntrack_l3proto *
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nf_ct_l3proto_find_get(u_int16_t l3proto)
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{
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struct nf_conntrack_l3proto *p;
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rcu_read_lock();
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p = __nf_ct_l3proto_find(l3proto);
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if (!try_module_get(p->me))
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p = &nf_conntrack_l3proto_generic;
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rcu_read_unlock();
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return p;
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}
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EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
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void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
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{
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module_put(p->me);
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}
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EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
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int
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nf_ct_l3proto_try_module_get(unsigned short l3proto)
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{
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int ret;
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struct nf_conntrack_l3proto *p;
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retry: p = nf_ct_l3proto_find_get(l3proto);
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if (p == &nf_conntrack_l3proto_generic) {
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ret = request_module("nf_conntrack-%d", l3proto);
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if (!ret)
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goto retry;
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return -EPROTOTYPE;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
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void nf_ct_l3proto_module_put(unsigned short l3proto)
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{
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struct nf_conntrack_l3proto *p;
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/* rcu_read_lock not necessary since the caller holds a reference */
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p = __nf_ct_l3proto_find(l3proto);
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module_put(p->me);
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}
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EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
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static int kill_l3proto(struct nf_conn *i, void *data)
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{
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return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
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}
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static int kill_l4proto(struct nf_conn *i, void *data)
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{
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struct nf_conntrack_l4proto *l4proto;
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l4proto = (struct nf_conntrack_l4proto *)data;
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return nf_ct_protonum(i) == l4proto->l4proto &&
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nf_ct_l3num(i) == l4proto->l3proto;
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}
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static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
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{
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int err = 0;
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#ifdef CONFIG_SYSCTL
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if (l3proto->ctl_table != NULL) {
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err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
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l3proto->ctl_table_path,
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l3proto->ctl_table, NULL);
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}
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#endif
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return err;
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}
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static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
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{
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#ifdef CONFIG_SYSCTL
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if (l3proto->ctl_table_header != NULL)
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nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
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l3proto->ctl_table, NULL);
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#endif
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}
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int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
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{
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int ret = 0;
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if (proto->l3proto >= AF_MAX)
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return -EBUSY;
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if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
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return -EINVAL;
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mutex_lock(&nf_ct_proto_mutex);
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if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
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ret = -EBUSY;
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goto out_unlock;
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}
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ret = nf_ct_l3proto_register_sysctl(proto);
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if (ret < 0)
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goto out_unlock;
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if (proto->nlattr_tuple_size)
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proto->nla_size = 3 * proto->nlattr_tuple_size();
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rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
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out_unlock:
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mutex_unlock(&nf_ct_proto_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
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void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
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{
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struct net *net;
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BUG_ON(proto->l3proto >= AF_MAX);
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mutex_lock(&nf_ct_proto_mutex);
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BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
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rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
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&nf_conntrack_l3proto_generic);
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nf_ct_l3proto_unregister_sysctl(proto);
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mutex_unlock(&nf_ct_proto_mutex);
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synchronize_rcu();
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/* Remove all contrack entries for this protocol */
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rtnl_lock();
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for_each_net(net)
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nf_ct_iterate_cleanup(net, kill_l3proto, proto);
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rtnl_unlock();
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}
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EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
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static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
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{
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int err = 0;
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#ifdef CONFIG_SYSCTL
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if (l4proto->ctl_table != NULL) {
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err = nf_ct_register_sysctl(l4proto->ctl_table_header,
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nf_net_netfilter_sysctl_path,
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l4proto->ctl_table,
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l4proto->ctl_table_users);
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if (err < 0)
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goto out;
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}
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#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
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if (l4proto->ctl_compat_table != NULL) {
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err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
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nf_net_ipv4_netfilter_sysctl_path,
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l4proto->ctl_compat_table, NULL);
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if (err == 0)
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goto out;
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nf_ct_unregister_sysctl(l4proto->ctl_table_header,
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l4proto->ctl_table,
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l4proto->ctl_table_users);
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}
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#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
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out:
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#endif /* CONFIG_SYSCTL */
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return err;
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}
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static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
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{
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#ifdef CONFIG_SYSCTL
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if (l4proto->ctl_table_header != NULL &&
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*l4proto->ctl_table_header != NULL)
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nf_ct_unregister_sysctl(l4proto->ctl_table_header,
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l4proto->ctl_table,
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l4proto->ctl_table_users);
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#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
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if (l4proto->ctl_compat_table_header != NULL)
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nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
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l4proto->ctl_compat_table, NULL);
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#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
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#endif /* CONFIG_SYSCTL */
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}
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/* FIXME: Allow NULL functions and sub in pointers to generic for
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them. --RR */
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int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
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{
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int ret = 0;
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if (l4proto->l3proto >= PF_MAX)
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return -EBUSY;
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if ((l4proto->to_nlattr && !l4proto->nlattr_size)
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|| (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
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return -EINVAL;
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mutex_lock(&nf_ct_proto_mutex);
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if (!nf_ct_protos[l4proto->l3proto]) {
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/* l3proto may be loaded latter. */
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struct nf_conntrack_l4proto **proto_array;
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int i;
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proto_array = kmalloc(MAX_NF_CT_PROTO *
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sizeof(struct nf_conntrack_l4proto *),
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GFP_KERNEL);
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if (proto_array == NULL) {
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ret = -ENOMEM;
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goto out_unlock;
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}
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for (i = 0; i < MAX_NF_CT_PROTO; i++)
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proto_array[i] = &nf_conntrack_l4proto_generic;
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nf_ct_protos[l4proto->l3proto] = proto_array;
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} else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
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&nf_conntrack_l4proto_generic) {
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ret = -EBUSY;
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goto out_unlock;
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}
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ret = nf_ct_l4proto_register_sysctl(l4proto);
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if (ret < 0)
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goto out_unlock;
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l4proto->nla_size = 0;
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if (l4proto->nlattr_size)
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l4proto->nla_size += l4proto->nlattr_size();
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if (l4proto->nlattr_tuple_size)
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l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();
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rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
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l4proto);
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out_unlock:
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mutex_unlock(&nf_ct_proto_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
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void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
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{
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struct net *net;
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BUG_ON(l4proto->l3proto >= PF_MAX);
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mutex_lock(&nf_ct_proto_mutex);
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BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
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rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
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&nf_conntrack_l4proto_generic);
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nf_ct_l4proto_unregister_sysctl(l4proto);
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mutex_unlock(&nf_ct_proto_mutex);
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synchronize_rcu();
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/* Remove all contrack entries for this protocol */
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rtnl_lock();
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for_each_net(net)
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nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
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rtnl_unlock();
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}
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EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
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int nf_conntrack_proto_init(void)
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{
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unsigned int i;
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int err;
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err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
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if (err < 0)
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return err;
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for (i = 0; i < AF_MAX; i++)
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rcu_assign_pointer(nf_ct_l3protos[i],
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&nf_conntrack_l3proto_generic);
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return 0;
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}
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void nf_conntrack_proto_fini(void)
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{
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unsigned int i;
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nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);
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/* free l3proto protocol tables */
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for (i = 0; i < PF_MAX; i++)
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kfree(nf_ct_protos[i]);
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}
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