net/netfilter/nfnetlink.c - arm/linux-arm64-legacy - Git at Google

 /* Netfilter messages via netlink socket. Allows for user space
  * protocol helpers and general trouble making from userspace.
  *
  * (C) 2001 by Jay Schulist <jschlst@samba.org>,
  * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
  * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
  *
  * Initial netfilter messages via netlink development funded and
  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
  *
  * Further development of this code funded by Astaro AG (http://www.astaro.com)
  *
  * This software may be used and distributed according to the terms
  * of the GNU General Public License, incorporated herein by reference.
  */

 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/socket.h>
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/timer.h>
 #include <linux/string.h>
 #include <linux/sockios.h>
 #include <linux/net.h>
 #include <linux/fcntl.h>
 #include <linux/skbuff.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <net/sock.h>
 #include <net/netlink.h>
 #include <linux/init.h>

 #include <linux/netlink.h>
 #include <linux/netfilter/nfnetlink.h>

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);

 static char __initdata nfversion[] = "0.30";

 static struct sock *nfnl = NULL;
 static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
 static DEFINE_MUTEX(nfnl_mutex);

 static void nfnl_lock(void)
 {
 	mutex_lock(&nfnl_mutex);
 }

 static int nfnl_trylock(void)
 {
 	return !mutex_trylock(&nfnl_mutex);
 }

 static void __nfnl_unlock(void)
 {
 	mutex_unlock(&nfnl_mutex);
 }

 static void nfnl_unlock(void)
 {
 	mutex_unlock(&nfnl_mutex);
 	if (nfnl->sk_receive_queue.qlen)
 		nfnl->sk_data_ready(nfnl, 0);
 }

 int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
 {
 	nfnl_lock();
 	if (subsys_table[n->subsys_id]) {
 		nfnl_unlock();
 		return -EBUSY;
 	}
 	subsys_table[n->subsys_id] = n;
 	nfnl_unlock();

 	return 0;
 }
 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);

 int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n)
 {
 	nfnl_lock();
 	subsys_table[n->subsys_id] = NULL;
 	nfnl_unlock();

 	return 0;
 }
 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);

 static inline struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
 {
 	u_int8_t subsys_id = NFNL_SUBSYS_ID(type);

 	if (subsys_id >= NFNL_SUBSYS_COUNT)
 		return NULL;

 	return subsys_table[subsys_id];
 }

 static inline struct nfnl_callback *
 nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss)
 {
 	u_int8_t cb_id = NFNL_MSG_TYPE(type);

 	if (cb_id >= ss->cb_count)
 		return NULL;

 	return &ss->cb[cb_id];
 }

 void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
 		const void *data)
 {
 	struct nfattr *nfa;
 	int size = NFA_LENGTH(attrlen);

 	nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
 	nfa->nfa_type = attrtype;
 	nfa->nfa_len  = size;
 	memcpy(NFA_DATA(nfa), data, attrlen);
 	memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
 }
 EXPORT_SYMBOL_GPL(__nfa_fill);

 void nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len)
 {
 	memset(tb, 0, sizeof(struct nfattr *) * maxattr);

 	while (NFA_OK(nfa, len)) {
 		unsigned flavor = NFA_TYPE(nfa);
 		if (flavor && flavor <= maxattr)
 			tb[flavor-1] = nfa;
 		nfa = NFA_NEXT(nfa, len);
 	}
 }
 EXPORT_SYMBOL_GPL(nfattr_parse);

 /**
  * nfnetlink_check_attributes - check and parse nfnetlink attributes
  *
  * subsys: nfnl subsystem for which this message is to be parsed
  * nlmsghdr: netlink message to be checked/parsed
  * cda: array of pointers, needs to be at least subsys->attr_count big
  *
  */
 static int
 nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
 			   struct nlmsghdr *nlh, struct nfattr *cda[])
 {
 	int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
 	u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 	u_int16_t attr_count = subsys->cb[cb_id].attr_count;

 	/* check attribute lengths. */
 	if (likely(nlh->nlmsg_len > min_len)) {
 		struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
 		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
 		nfattr_parse(cda, attr_count, attr, attrlen);
 	}

 	/* implicit: if nlmsg_len == min_len, we return 0, and an empty
 	 * (zeroed) cda[] array. The message is valid, but empty. */

 	return 0;
 }

 int nfnetlink_has_listeners(unsigned int group)
 {
 	return netlink_has_listeners(nfnl, group);
 }
 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);

 int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
 {
 	int err = 0;

 	NETLINK_CB(skb).dst_group = group;
 	if (echo)
 		atomic_inc(&skb->users);
 	netlink_broadcast(nfnl, skb, pid, group, gfp_any());
 	if (echo)
 		err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT);

 	return err;
 }
 EXPORT_SYMBOL_GPL(nfnetlink_send);

 int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
 {
 	return netlink_unicast(nfnl, skb, pid, flags);
 }
 EXPORT_SYMBOL_GPL(nfnetlink_unicast);

 /* Process one complete nfnetlink message. */
 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct nfnl_callback *nc;
 	struct nfnetlink_subsystem *ss;
 	int type, err;

 	if (security_netlink_recv(skb, CAP_NET_ADMIN))
 		return -EPERM;

 	/* All the messages must at least contain nfgenmsg */
 	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg)))
 		return 0;

 	type = nlh->nlmsg_type;
 	ss = nfnetlink_get_subsys(type);
 	if (!ss) {
 #ifdef CONFIG_KMOD
 		/* don't call nfnl_unlock, since it would reenter
 		 * with further packet processing */
 		__nfnl_unlock();
 		request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
 		nfnl_lock();
 		ss = nfnetlink_get_subsys(type);
 		if (!ss)
 #endif
 			return -EINVAL;
 	}

 	nc = nfnetlink_find_client(type, ss);
 	if (!nc)
 		return -EINVAL;

 	{
 		u_int16_t attr_count =
 			ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count;
 		struct nfattr *cda[attr_count];

 		memset(cda, 0, sizeof(struct nfattr *) * attr_count);

 		err = nfnetlink_check_attributes(ss, nlh, cda);
 		if (err < 0)
 			return err;
 		return nc->call(nfnl, skb, nlh, cda);
 	}
 }

 static void nfnetlink_rcv(struct sock *sk, int len)
 {
 	unsigned int qlen = 0;

 	do {
 		if (nfnl_trylock())
 			return;
 		netlink_run_queue(sk, &qlen, nfnetlink_rcv_msg);
 		__nfnl_unlock();
 	} while (qlen);
 }

 static void __exit nfnetlink_exit(void)
 {
 	printk("Removing netfilter NETLINK layer.\n");
 	sock_release(nfnl->sk_socket);
 	return;
 }

 static int __init nfnetlink_init(void)
 {
 	printk("Netfilter messages via NETLINK v%s.\n", nfversion);

 	nfnl = netlink_kernel_create(NETLINK_NETFILTER, NFNLGRP_MAX,
 				     nfnetlink_rcv, NULL, THIS_MODULE);
 	if (!nfnl) {
 		printk(KERN_ERR "cannot initialize nfnetlink!\n");
 		return -1;
 	}

 	return 0;
 }

 module_init(nfnetlink_init);
 module_exit(nfnetlink_exit);
	/* Netfilter messages via netlink socket. Allows for user space
	* protocol helpers and general trouble making from userspace.
	*
	* (C) 2001 by Jay Schulist <jschlst@samba.org>,
	* (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
	* (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org>
	*
	* Initial netfilter messages via netlink development funded and
	* generally made possible by Network Robots, Inc. (www.networkrobots.com)
	*
	* Further development of this code funded by Astaro AG (http://www.astaro.com)
	*
	* This software may be used and distributed according to the terms
	* of the GNU General Public License, incorporated herein by reference.
	*/

	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/socket.h>
	#include <linux/kernel.h>
	#include <linux/major.h>
	#include <linux/timer.h>
	#include <linux/string.h>
	#include <linux/sockios.h>
	#include <linux/net.h>
	#include <linux/fcntl.h>
	#include <linux/skbuff.h>
	#include <asm/uaccess.h>
	#include <asm/system.h>
	#include <net/sock.h>
	#include <net/netlink.h>
	#include <linux/init.h>

	#include <linux/netlink.h>
	#include <linux/netfilter/nfnetlink.h>

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
	MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);

	static char __initdata nfversion[] = "0.30";

	static struct sock *nfnl = NULL;
	static struct nfnetlink_subsystem *subsys_table[NFNL_SUBSYS_COUNT];
	static DEFINE_MUTEX(nfnl_mutex);

	static void nfnl_lock(void)
	{
	mutex_lock(&nfnl_mutex);
	}

	static int nfnl_trylock(void)
	{
	return !mutex_trylock(&nfnl_mutex);
	}

	static void __nfnl_unlock(void)
	{
	mutex_unlock(&nfnl_mutex);
	}

	static void nfnl_unlock(void)
	{
	mutex_unlock(&nfnl_mutex);
	if (nfnl->sk_receive_queue.qlen)
	nfnl->sk_data_ready(nfnl, 0);
	}

	int nfnetlink_subsys_register(struct nfnetlink_subsystem *n)
	{
	nfnl_lock();
	if (subsys_table[n->subsys_id]) {
	nfnl_unlock();
	return -EBUSY;
	}
	subsys_table[n->subsys_id] = n;
	nfnl_unlock();

	return 0;
	}
	EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);

	int nfnetlink_subsys_unregister(struct nfnetlink_subsystem *n)
	{
	nfnl_lock();
	subsys_table[n->subsys_id] = NULL;
	nfnl_unlock();

	return 0;
	}
	EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);

	static inline struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
	{
	u_int8_t subsys_id = NFNL_SUBSYS_ID(type);

	if (subsys_id >= NFNL_SUBSYS_COUNT)
	return NULL;

	return subsys_table[subsys_id];
	}

	static inline struct nfnl_callback *
	nfnetlink_find_client(u_int16_t type, struct nfnetlink_subsystem *ss)
	{
	u_int8_t cb_id = NFNL_MSG_TYPE(type);

	if (cb_id >= ss->cb_count)
	return NULL;

	return &ss->cb[cb_id];
	}

	void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
	const void *data)
	{
	struct nfattr *nfa;
	int size = NFA_LENGTH(attrlen);

	nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
	nfa->nfa_type = attrtype;
	nfa->nfa_len = size;
	memcpy(NFA_DATA(nfa), data, attrlen);
	memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
	}
	EXPORT_SYMBOL_GPL(__nfa_fill);

	void nfattr_parse(struct nfattr tb[], int maxattr, struct nfattr nfa, int len)
	{
	memset(tb, 0, sizeof(struct nfattr ) maxattr);

	while (NFA_OK(nfa, len)) {
	unsigned flavor = NFA_TYPE(nfa);
	if (flavor && flavor <= maxattr)
	tb[flavor-1] = nfa;
	nfa = NFA_NEXT(nfa, len);
	}
	}
	EXPORT_SYMBOL_GPL(nfattr_parse);

	/**
	* nfnetlink_check_attributes - check and parse nfnetlink attributes
	*
	* subsys: nfnl subsystem for which this message is to be parsed
	* nlmsghdr: netlink message to be checked/parsed
	* cda: array of pointers, needs to be at least subsys->attr_count big
	*
	*/
	static int
	nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
	struct nlmsghdr nlh, struct nfattr cda[])
	{
	int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
	u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
	u_int16_t attr_count = subsys->cb[cb_id].attr_count;

	/* check attribute lengths. */
	if (likely(nlh->nlmsg_len > min_len)) {
	struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
	int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
	nfattr_parse(cda, attr_count, attr, attrlen);
	}

	/* implicit: if nlmsg_len == min_len, we return 0, and an empty
	* (zeroed) cda[] array. The message is valid, but empty. */

	return 0;
	}

	int nfnetlink_has_listeners(unsigned int group)
	{
	return netlink_has_listeners(nfnl, group);
	}
	EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);

	int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
	{
	int err = 0;

	NETLINK_CB(skb).dst_group = group;
	if (echo)
	atomic_inc(&skb->users);
	netlink_broadcast(nfnl, skb, pid, group, gfp_any());
	if (echo)
	err = netlink_unicast(nfnl, skb, pid, MSG_DONTWAIT);

	return err;
	}
	EXPORT_SYMBOL_GPL(nfnetlink_send);

	int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags)
	{
	return netlink_unicast(nfnl, skb, pid, flags);
	}
	EXPORT_SYMBOL_GPL(nfnetlink_unicast);

	/* Process one complete nfnetlink message. */
	static int nfnetlink_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh)
	{
	struct nfnl_callback *nc;
	struct nfnetlink_subsystem *ss;
	int type, err;

	if (security_netlink_recv(skb, CAP_NET_ADMIN))
	return -EPERM;

	/* All the messages must at least contain nfgenmsg */
	if (nlh->nlmsg_len < NLMSG_SPACE(sizeof(struct nfgenmsg)))
	return 0;

	type = nlh->nlmsg_type;
	ss = nfnetlink_get_subsys(type);
	if (!ss) {
	#ifdef CONFIG_KMOD
	/* don't call nfnl_unlock, since it would reenter
	* with further packet processing */
	__nfnl_unlock();
	request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
	nfnl_lock();
	ss = nfnetlink_get_subsys(type);
	if (!ss)
	#endif
	return -EINVAL;
	}

	nc = nfnetlink_find_client(type, ss);
	if (!nc)
	return -EINVAL;

	{
	u_int16_t attr_count =
	ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count;
	struct nfattr *cda[attr_count];

	memset(cda, 0, sizeof(struct nfattr ) attr_count);

	err = nfnetlink_check_attributes(ss, nlh, cda);
	if (err < 0)
	return err;
	return nc->call(nfnl, skb, nlh, cda);
	}
	}

	static void nfnetlink_rcv(struct sock *sk, int len)
	{
	unsigned int qlen = 0;

	do {
	if (nfnl_trylock())
	return;
	netlink_run_queue(sk, &qlen, nfnetlink_rcv_msg);
	__nfnl_unlock();
	} while (qlen);
	}

	static void __exit nfnetlink_exit(void)
	{
	printk("Removing netfilter NETLINK layer.\n");
	sock_release(nfnl->sk_socket);
	return;
	}

	static int __init nfnetlink_init(void)
	{
	printk("Netfilter messages via NETLINK v%s.\n", nfversion);

	nfnl = netlink_kernel_create(NETLINK_NETFILTER, NFNLGRP_MAX,
	nfnetlink_rcv, NULL, THIS_MODULE);
	if (!nfnl) {
	printk(KERN_ERR "cannot initialize nfnetlink!\n");
	return -1;
	}

	return 0;
	}

	module_init(nfnetlink_init);
	module_exit(nfnetlink_exit);