af_netlink.c 39.7 KB
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/*
 * NETLINK      Kernel-user communication protocol.
 *
 * 		Authors:	Alan Cox <alan@redhat.com>
 * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 * 
 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
 *                               added netlink_proto_exit
 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
 * 				 use nlk_sk, as sk->protinfo is on a diet 8)
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 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
 * 				 - inc module use count of module that owns
 * 				   the kernel socket in case userspace opens
 * 				   socket of same protocol
 * 				 - remove all module support, since netlink is
 * 				   mandatory if CONFIG_NET=y these days
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 */

#include <linux/module.h>

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#include <linux/capability.h>
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#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/security.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <linux/types.h>
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#include <linux/audit.h>
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#include <linux/selinux.h>
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#include <net/sock.h>
#include <net/scm.h>
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#include <net/netlink.h>
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#define NLGRPSZ(x)	(ALIGN(x, sizeof(unsigned long) * 8) / 8)
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struct netlink_sock {
	/* struct sock has to be the first member of netlink_sock */
	struct sock		sk;
	u32			pid;
	u32			dst_pid;
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	u32			dst_group;
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	u32			flags;
	u32			subscriptions;
	u32			ngroups;
	unsigned long		*groups;
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	unsigned long		state;
	wait_queue_head_t	wait;
	struct netlink_callback	*cb;
	spinlock_t		cb_lock;
	void			(*data_ready)(struct sock *sk, int bytes);
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	struct module		*module;
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};

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#define NETLINK_KERNEL_SOCKET	0x1
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#define NETLINK_RECV_PKTINFO	0x2
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static inline struct netlink_sock *nlk_sk(struct sock *sk)
{
	return (struct netlink_sock *)sk;
}

struct nl_pid_hash {
	struct hlist_head *table;
	unsigned long rehash_time;

	unsigned int mask;
	unsigned int shift;

	unsigned int entries;
	unsigned int max_shift;

	u32 rnd;
};

struct netlink_table {
	struct nl_pid_hash hash;
	struct hlist_head mc_list;
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	unsigned long *listeners;
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	unsigned int nl_nonroot;
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	unsigned int groups;
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	struct module *module;
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	int registered;
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};

static struct netlink_table *nl_table;

static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);

static int netlink_dump(struct sock *sk);
static void netlink_destroy_callback(struct netlink_callback *cb);

static DEFINE_RWLOCK(nl_table_lock);
static atomic_t nl_table_users = ATOMIC_INIT(0);

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static ATOMIC_NOTIFIER_HEAD(netlink_chain);
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static u32 netlink_group_mask(u32 group)
{
	return group ? 1 << (group - 1) : 0;
}

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static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
{
	return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
}

static void netlink_sock_destruct(struct sock *sk)
{
	skb_queue_purge(&sk->sk_receive_queue);

	if (!sock_flag(sk, SOCK_DEAD)) {
		printk("Freeing alive netlink socket %p\n", sk);
		return;
	}
	BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
	BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
	BUG_TRAP(!nlk_sk(sk)->cb);
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	BUG_TRAP(!nlk_sk(sk)->groups);
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}

/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
 * Look, when several writers sleep and reader wakes them up, all but one
 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
 * this, _but_ remember, it adds useless work on UP machines.
 */

static void netlink_table_grab(void)
{
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	write_lock_irq(&nl_table_lock);
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	if (atomic_read(&nl_table_users)) {
		DECLARE_WAITQUEUE(wait, current);

		add_wait_queue_exclusive(&nl_table_wait, &wait);
		for(;;) {
			set_current_state(TASK_UNINTERRUPTIBLE);
			if (atomic_read(&nl_table_users) == 0)
				break;
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			write_unlock_irq(&nl_table_lock);
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			schedule();
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			write_lock_irq(&nl_table_lock);
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		}

		__set_current_state(TASK_RUNNING);
		remove_wait_queue(&nl_table_wait, &wait);
	}
}

static __inline__ void netlink_table_ungrab(void)
{
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	write_unlock_irq(&nl_table_lock);
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	wake_up(&nl_table_wait);
}

static __inline__ void
netlink_lock_table(void)
{
	/* read_lock() synchronizes us to netlink_table_grab */

	read_lock(&nl_table_lock);
	atomic_inc(&nl_table_users);
	read_unlock(&nl_table_lock);
}

static __inline__ void
netlink_unlock_table(void)
{
	if (atomic_dec_and_test(&nl_table_users))
		wake_up(&nl_table_wait);
}

static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
{
	struct nl_pid_hash *hash = &nl_table[protocol].hash;
	struct hlist_head *head;
	struct sock *sk;
	struct hlist_node *node;

	read_lock(&nl_table_lock);
	head = nl_pid_hashfn(hash, pid);
	sk_for_each(sk, node, head) {
		if (nlk_sk(sk)->pid == pid) {
			sock_hold(sk);
			goto found;
		}
	}
	sk = NULL;
found:
	read_unlock(&nl_table_lock);
	return sk;
}

static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
{
	if (size <= PAGE_SIZE)
		return kmalloc(size, GFP_ATOMIC);
	else
		return (struct hlist_head *)
			__get_free_pages(GFP_ATOMIC, get_order(size));
}

static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
{
	if (size <= PAGE_SIZE)
		kfree(table);
	else
		free_pages((unsigned long)table, get_order(size));
}

static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
{
	unsigned int omask, mask, shift;
	size_t osize, size;
	struct hlist_head *otable, *table;
	int i;

	omask = mask = hash->mask;
	osize = size = (mask + 1) * sizeof(*table);
	shift = hash->shift;

	if (grow) {
		if (++shift > hash->max_shift)
			return 0;
		mask = mask * 2 + 1;
		size *= 2;
	}

	table = nl_pid_hash_alloc(size);
	if (!table)
		return 0;

	memset(table, 0, size);
	otable = hash->table;
	hash->table = table;
	hash->mask = mask;
	hash->shift = shift;
	get_random_bytes(&hash->rnd, sizeof(hash->rnd));

	for (i = 0; i <= omask; i++) {
		struct sock *sk;
		struct hlist_node *node, *tmp;

		sk_for_each_safe(sk, node, tmp, &otable[i])
			__sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
	}

	nl_pid_hash_free(otable, osize);
	hash->rehash_time = jiffies + 10 * 60 * HZ;
	return 1;
}

static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
{
	int avg = hash->entries >> hash->shift;

	if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
		return 1;

	if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
		nl_pid_hash_rehash(hash, 0);
		return 1;
	}

	return 0;
}

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static const struct proto_ops netlink_ops;
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static void
netlink_update_listeners(struct sock *sk)
{
	struct netlink_table *tbl = &nl_table[sk->sk_protocol];
	struct hlist_node *node;
	unsigned long mask;
	unsigned int i;

	for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
		mask = 0;
		sk_for_each_bound(sk, node, &tbl->mc_list)
			mask |= nlk_sk(sk)->groups[i];
		tbl->listeners[i] = mask;
	}
	/* this function is only called with the netlink table "grabbed", which
	 * makes sure updates are visible before bind or setsockopt return. */
}

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static int netlink_insert(struct sock *sk, u32 pid)
{
	struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
	struct hlist_head *head;
	int err = -EADDRINUSE;
	struct sock *osk;
	struct hlist_node *node;
	int len;

	netlink_table_grab();
	head = nl_pid_hashfn(hash, pid);
	len = 0;
	sk_for_each(osk, node, head) {
		if (nlk_sk(osk)->pid == pid)
			break;
		len++;
	}
	if (node)
		goto err;

	err = -EBUSY;
	if (nlk_sk(sk)->pid)
		goto err;

	err = -ENOMEM;
	if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
		goto err;

	if (len && nl_pid_hash_dilute(hash, len))
		head = nl_pid_hashfn(hash, pid);
	hash->entries++;
	nlk_sk(sk)->pid = pid;
	sk_add_node(sk, head);
	err = 0;

err:
	netlink_table_ungrab();
	return err;
}

static void netlink_remove(struct sock *sk)
{
	netlink_table_grab();
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	if (sk_del_node_init(sk))
		nl_table[sk->sk_protocol].hash.entries--;
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	if (nlk_sk(sk)->subscriptions)
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		__sk_del_bind_node(sk);
	netlink_table_ungrab();
}

static struct proto netlink_proto = {
	.name	  = "NETLINK",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct netlink_sock),
};

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static int __netlink_create(struct socket *sock, int protocol)
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{
	struct sock *sk;
	struct netlink_sock *nlk;
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	sock->ops = &netlink_ops;

	sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
	if (!sk)
		return -ENOMEM;

	sock_init_data(sock, sk);

	nlk = nlk_sk(sk);
	spin_lock_init(&nlk->cb_lock);
	init_waitqueue_head(&nlk->wait);

	sk->sk_destruct = netlink_sock_destruct;
	sk->sk_protocol = protocol;
	return 0;
}

static int netlink_create(struct socket *sock, int protocol)
{
	struct module *module = NULL;
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	struct netlink_sock *nlk;
	unsigned int groups;
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	int err = 0;
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	sock->state = SS_UNCONNECTED;

	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
		return -ESOCKTNOSUPPORT;

	if (protocol<0 || protocol >= MAX_LINKS)
		return -EPROTONOSUPPORT;

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	netlink_lock_table();
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	if (!nl_table[protocol].registered) {
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		netlink_unlock_table();
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		request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
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		netlink_lock_table();
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	}
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#endif
	if (nl_table[protocol].registered &&
	    try_module_get(nl_table[protocol].module))
		module = nl_table[protocol].module;
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	groups = nl_table[protocol].groups;
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	netlink_unlock_table();
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	if ((err = __netlink_create(sock, protocol)) < 0)
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		goto out_module;

	nlk = nlk_sk(sock->sk);
	nlk->module = module;
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out:
	return err;
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out_module:
	module_put(module);
	goto out;
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}

static int netlink_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk;

	if (!sk)
		return 0;

	netlink_remove(sk);
	nlk = nlk_sk(sk);

	spin_lock(&nlk->cb_lock);
	if (nlk->cb) {
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		if (nlk->cb->done)
			nlk->cb->done(nlk->cb);
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		netlink_destroy_callback(nlk->cb);
		nlk->cb = NULL;
	}
	spin_unlock(&nlk->cb_lock);

	/* OK. Socket is unlinked, and, therefore,
	   no new packets will arrive */

	sock_orphan(sk);
	sock->sk = NULL;
	wake_up_interruptible_all(&nlk->wait);

	skb_queue_purge(&sk->sk_write_queue);

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	if (nlk->pid && !nlk->subscriptions) {
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		struct netlink_notify n = {
						.protocol = sk->sk_protocol,
						.pid = nlk->pid,
					  };
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		atomic_notifier_call_chain(&netlink_chain,
				NETLINK_URELEASE, &n);
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	}	
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	if (nlk->module)
		module_put(nlk->module);
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	netlink_table_grab();
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	if (nlk->flags & NETLINK_KERNEL_SOCKET) {
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		kfree(nl_table[sk->sk_protocol].listeners);
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		nl_table[sk->sk_protocol].module = NULL;
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		nl_table[sk->sk_protocol].registered = 0;
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	} else if (nlk->subscriptions)
		netlink_update_listeners(sk);
	netlink_table_ungrab();
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	kfree(nlk->groups);
	nlk->groups = NULL;

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	sock_put(sk);
	return 0;
}

static int netlink_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
	struct hlist_head *head;
	struct sock *osk;
	struct hlist_node *node;
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	s32 pid = current->tgid;
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	int err;
	static s32 rover = -4097;

retry:
	cond_resched();
	netlink_table_grab();
	head = nl_pid_hashfn(hash, pid);
	sk_for_each(osk, node, head) {
		if (nlk_sk(osk)->pid == pid) {
			/* Bind collision, search negative pid values. */
			pid = rover--;
			if (rover > -4097)
				rover = -4097;
			netlink_table_ungrab();
			goto retry;
		}
	}
	netlink_table_ungrab();

	err = netlink_insert(sk, pid);
	if (err == -EADDRINUSE)
		goto retry;
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	/* If 2 threads race to autobind, that is fine.  */
	if (err == -EBUSY)
		err = 0;

	return err;
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}

static inline int netlink_capable(struct socket *sock, unsigned int flag) 
{ 
	return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
	       capable(CAP_NET_ADMIN);
} 

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static void
netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
{
	struct netlink_sock *nlk = nlk_sk(sk);

	if (nlk->subscriptions && !subscriptions)
		__sk_del_bind_node(sk);
	else if (!nlk->subscriptions && subscriptions)
		sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
	nlk->subscriptions = subscriptions;
}

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static int netlink_alloc_groups(struct sock *sk)
{
	struct netlink_sock *nlk = nlk_sk(sk);
	unsigned int groups;
	int err = 0;

	netlink_lock_table();
	groups = nl_table[sk->sk_protocol].groups;
	if (!nl_table[sk->sk_protocol].registered)
		err = -ENOENT;
	netlink_unlock_table();

	if (err)
		return err;

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	nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
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	if (nlk->groups == NULL)
		return -ENOMEM;
	nlk->ngroups = groups;
	return 0;
}

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static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
	int err;
	
	if (nladdr->nl_family != AF_NETLINK)
		return -EINVAL;

	/* Only superuser is allowed to listen multicasts */
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	if (nladdr->nl_groups) {
		if (!netlink_capable(sock, NL_NONROOT_RECV))
			return -EPERM;
		if (nlk->groups == NULL) {
			err = netlink_alloc_groups(sk);
			if (err)
				return err;
		}
	}
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	if (nlk->pid) {
		if (nladdr->nl_pid != nlk->pid)
			return -EINVAL;
	} else {
		err = nladdr->nl_pid ?
			netlink_insert(sk, nladdr->nl_pid) :
			netlink_autobind(sock);
		if (err)
			return err;
	}

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	if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
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		return 0;

	netlink_table_grab();
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	netlink_update_subscriptions(sk, nlk->subscriptions +
	                                 hweight32(nladdr->nl_groups) -
	                                 hweight32(nlk->groups[0]));
	nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 
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	netlink_update_listeners(sk);
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	netlink_table_ungrab();

	return 0;
}

static int netlink_connect(struct socket *sock, struct sockaddr *addr,
			   int alen, int flags)
{
	int err = 0;
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;

	if (addr->sa_family == AF_UNSPEC) {
		sk->sk_state	= NETLINK_UNCONNECTED;
		nlk->dst_pid	= 0;
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		nlk->dst_group  = 0;
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		return 0;
	}
	if (addr->sa_family != AF_NETLINK)
		return -EINVAL;

	/* Only superuser is allowed to send multicasts */
	if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
		return -EPERM;

	if (!nlk->pid)
		err = netlink_autobind(sock);

	if (err == 0) {
		sk->sk_state	= NETLINK_CONNECTED;
		nlk->dst_pid 	= nladdr->nl_pid;
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		nlk->dst_group  = ffs(nladdr->nl_groups);
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	}

	return err;
}

static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
{
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
	
	nladdr->nl_family = AF_NETLINK;
	nladdr->nl_pad = 0;
	*addr_len = sizeof(*nladdr);

	if (peer) {
		nladdr->nl_pid = nlk->dst_pid;
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		nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
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	} else {
		nladdr->nl_pid = nlk->pid;
666
		nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
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	}
	return 0;
}

static void netlink_overrun(struct sock *sk)
{
	if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
		sk->sk_err = ENOBUFS;
		sk->sk_error_report(sk);
	}
}

static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
{
	int protocol = ssk->sk_protocol;
	struct sock *sock;
	struct netlink_sock *nlk;

	sock = netlink_lookup(protocol, pid);
	if (!sock)
		return ERR_PTR(-ECONNREFUSED);

	/* Don't bother queuing skb if kernel socket has no input function */
	nlk = nlk_sk(sock);
	if ((nlk->pid == 0 && !nlk->data_ready) ||
	    (sock->sk_state == NETLINK_CONNECTED &&
	     nlk->dst_pid != nlk_sk(ssk)->pid)) {
		sock_put(sock);
		return ERR_PTR(-ECONNREFUSED);
	}
	return sock;
}

struct sock *netlink_getsockbyfilp(struct file *filp)
{
	struct inode *inode = filp->f_dentry->d_inode;
	struct sock *sock;

	if (!S_ISSOCK(inode->i_mode))
		return ERR_PTR(-ENOTSOCK);

	sock = SOCKET_I(inode)->sk;
	if (sock->sk_family != AF_NETLINK)
		return ERR_PTR(-EINVAL);

	sock_hold(sock);
	return sock;
}

/*
 * Attach a skb to a netlink socket.
 * The caller must hold a reference to the destination socket. On error, the
 * reference is dropped. The skb is not send to the destination, just all
 * all error checks are performed and memory in the queue is reserved.
 * Return values:
 * < 0: error. skb freed, reference to sock dropped.
 * 0: continue
 * 1: repeat lookup - reference dropped while waiting for socket memory.
 */
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int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
		long timeo, struct sock *ssk)
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{
	struct netlink_sock *nlk;

	nlk = nlk_sk(sk);

	if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
	    test_bit(0, &nlk->state)) {
		DECLARE_WAITQUEUE(wait, current);
		if (!timeo) {
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Alexey Kuznetsov 已提交
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			if (!ssk || nlk_sk(ssk)->pid == 0)
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				netlink_overrun(sk);
			sock_put(sk);
			kfree_skb(skb);
			return -EAGAIN;
		}

		__set_current_state(TASK_INTERRUPTIBLE);
		add_wait_queue(&nlk->wait, &wait);

		if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
		     test_bit(0, &nlk->state)) &&
		    !sock_flag(sk, SOCK_DEAD))
			timeo = schedule_timeout(timeo);

		__set_current_state(TASK_RUNNING);
		remove_wait_queue(&nlk->wait, &wait);
		sock_put(sk);

		if (signal_pending(current)) {
			kfree_skb(skb);
			return sock_intr_errno(timeo);
		}
		return 1;
	}
	skb_set_owner_r(skb, sk);
	return 0;
}

int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
{
	int len = skb->len;

	skb_queue_tail(&sk->sk_receive_queue, skb);
	sk->sk_data_ready(sk, len);
	sock_put(sk);
	return len;
}

void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
{
	kfree_skb(skb);
	sock_put(sk);
}

782
static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
A
Al Viro 已提交
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					   gfp_t allocation)
L
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{
	int delta;

	skb_orphan(skb);

	delta = skb->end - skb->tail;
	if (delta * 2 < skb->truesize)
		return skb;

	if (skb_shared(skb)) {
		struct sk_buff *nskb = skb_clone(skb, allocation);
		if (!nskb)
			return skb;
		kfree_skb(skb);
		skb = nskb;
	}

	if (!pskb_expand_head(skb, 0, -delta, allocation))
		skb->truesize -= delta;

	return skb;
}

int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
{
	struct sock *sk;
	int err;
	long timeo;

	skb = netlink_trim(skb, gfp_any());

	timeo = sock_sndtimeo(ssk, nonblock);
retry:
	sk = netlink_getsockbypid(ssk, pid);
	if (IS_ERR(sk)) {
		kfree_skb(skb);
		return PTR_ERR(sk);
	}
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Alexey Kuznetsov 已提交
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	err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
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	if (err == 1)
		goto retry;
	if (err)
		return err;

	return netlink_sendskb(sk, skb, ssk->sk_protocol);
}

831 832 833 834 835 836 837 838 839 840 841
int netlink_has_listeners(struct sock *sk, unsigned int group)
{
	int res = 0;

	BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
	if (group - 1 < nl_table[sk->sk_protocol].groups)
		res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners);
	return res;
}
EXPORT_SYMBOL_GPL(netlink_has_listeners);

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static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
{
	struct netlink_sock *nlk = nlk_sk(sk);

	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
	    !test_bit(0, &nlk->state)) {
		skb_set_owner_r(skb, sk);
		skb_queue_tail(&sk->sk_receive_queue, skb);
		sk->sk_data_ready(sk, skb->len);
		return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
	}
	return -1;
}

struct netlink_broadcast_data {
	struct sock *exclude_sk;
	u32 pid;
	u32 group;
	int failure;
	int congested;
	int delivered;
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Al Viro 已提交
863
	gfp_t allocation;
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	struct sk_buff *skb, *skb2;
};

static inline int do_one_broadcast(struct sock *sk,
				   struct netlink_broadcast_data *p)
{
	struct netlink_sock *nlk = nlk_sk(sk);
	int val;

	if (p->exclude_sk == sk)
		goto out;

876 877
	if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
	    !test_bit(p->group - 1, nlk->groups))
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		goto out;

	if (p->failure) {
		netlink_overrun(sk);
		goto out;
	}

	sock_hold(sk);
	if (p->skb2 == NULL) {
887
		if (skb_shared(p->skb)) {
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			p->skb2 = skb_clone(p->skb, p->allocation);
		} else {
890 891 892 893 894 895
			p->skb2 = skb_get(p->skb);
			/*
			 * skb ownership may have been set when
			 * delivered to a previous socket.
			 */
			skb_orphan(p->skb2);
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		}
	}
	if (p->skb2 == NULL) {
		netlink_overrun(sk);
		/* Clone failed. Notify ALL listeners. */
		p->failure = 1;
	} else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
		netlink_overrun(sk);
	} else {
		p->congested |= val;
		p->delivered = 1;
		p->skb2 = NULL;
	}
	sock_put(sk);

out:
	return 0;
}

int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
A
Al Viro 已提交
916
		      u32 group, gfp_t allocation)
L
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{
	struct netlink_broadcast_data info;
	struct hlist_node *node;
	struct sock *sk;

	skb = netlink_trim(skb, allocation);

	info.exclude_sk = ssk;
	info.pid = pid;
	info.group = group;
	info.failure = 0;
	info.congested = 0;
	info.delivered = 0;
	info.allocation = allocation;
	info.skb = skb;
	info.skb2 = NULL;

	/* While we sleep in clone, do not allow to change socket list */

	netlink_lock_table();

	sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
		do_one_broadcast(sk, &info);

941 942
	kfree_skb(skb);

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	netlink_unlock_table();

	if (info.skb2)
		kfree_skb(info.skb2);

	if (info.delivered) {
		if (info.congested && (allocation & __GFP_WAIT))
			yield();
		return 0;
	}
	if (info.failure)
		return -ENOBUFS;
	return -ESRCH;
}

struct netlink_set_err_data {
	struct sock *exclude_sk;
	u32 pid;
	u32 group;
	int code;
};

static inline int do_one_set_err(struct sock *sk,
				 struct netlink_set_err_data *p)
{
	struct netlink_sock *nlk = nlk_sk(sk);

	if (sk == p->exclude_sk)
		goto out;

973 974
	if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
	    !test_bit(p->group - 1, nlk->groups))
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Linus Torvalds 已提交
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		goto out;

	sk->sk_err = p->code;
	sk->sk_error_report(sk);
out:
	return 0;
}

void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
{
	struct netlink_set_err_data info;
	struct hlist_node *node;
	struct sock *sk;

	info.exclude_sk = ssk;
	info.pid = pid;
	info.group = group;
	info.code = code;

	read_lock(&nl_table_lock);

	sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
		do_one_set_err(sk, &info);

	read_unlock(&nl_table_lock);
}

1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
static int netlink_setsockopt(struct socket *sock, int level, int optname,
                              char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	int val = 0, err;

	if (level != SOL_NETLINK)
		return -ENOPROTOOPT;

	if (optlen >= sizeof(int) &&
	    get_user(val, (int __user *)optval))
		return -EFAULT;

	switch (optname) {
	case NETLINK_PKTINFO:
		if (val)
			nlk->flags |= NETLINK_RECV_PKTINFO;
		else
			nlk->flags &= ~NETLINK_RECV_PKTINFO;
		err = 0;
		break;
	case NETLINK_ADD_MEMBERSHIP:
	case NETLINK_DROP_MEMBERSHIP: {
		unsigned int subscriptions;
		int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;

		if (!netlink_capable(sock, NL_NONROOT_RECV))
			return -EPERM;
1031 1032 1033 1034 1035
		if (nlk->groups == NULL) {
			err = netlink_alloc_groups(sk);
			if (err)
				return err;
		}
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
		if (!val || val - 1 >= nlk->ngroups)
			return -EINVAL;
		netlink_table_grab();
		old = test_bit(val - 1, nlk->groups);
		subscriptions = nlk->subscriptions - old + new;
		if (new)
			__set_bit(val - 1, nlk->groups);
		else
			__clear_bit(val - 1, nlk->groups);
		netlink_update_subscriptions(sk, subscriptions);
1046
		netlink_update_listeners(sk);
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
		netlink_table_ungrab();
		err = 0;
		break;
	}
	default:
		err = -ENOPROTOOPT;
	}
	return err;
}

static int netlink_getsockopt(struct socket *sock, int level, int optname,
                              char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	int len, val, err;

	if (level != SOL_NETLINK)
		return -ENOPROTOOPT;

	if (get_user(len, optlen))
		return -EFAULT;
	if (len < 0)
		return -EINVAL;

	switch (optname) {
	case NETLINK_PKTINFO:
		if (len < sizeof(int))
			return -EINVAL;
		len = sizeof(int);
		val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
		put_user(len, optlen);
		put_user(val, optval);
		err = 0;
		break;
	default:
		err = -ENOPROTOOPT;
	}
	return err;
}

static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
	struct nl_pktinfo info;

	info.group = NETLINK_CB(skb).dst_group;
	put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
}

L
Linus Torvalds 已提交
1096 1097 1098 1099
static inline void netlink_rcv_wake(struct sock *sk)
{
	struct netlink_sock *nlk = nlk_sk(sk);

1100
	if (skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
		clear_bit(0, &nlk->state);
	if (!test_bit(0, &nlk->state))
		wake_up_interruptible(&nlk->wait);
}

static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
			   struct msghdr *msg, size_t len)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	struct sockaddr_nl *addr=msg->msg_name;
	u32 dst_pid;
1114
	u32 dst_group;
L
Linus Torvalds 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
	struct sk_buff *skb;
	int err;
	struct scm_cookie scm;

	if (msg->msg_flags&MSG_OOB)
		return -EOPNOTSUPP;

	if (NULL == siocb->scm)
		siocb->scm = &scm;
	err = scm_send(sock, msg, siocb->scm);
	if (err < 0)
		return err;

	if (msg->msg_namelen) {
		if (addr->nl_family != AF_NETLINK)
			return -EINVAL;
		dst_pid = addr->nl_pid;
1132 1133
		dst_group = ffs(addr->nl_groups);
		if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
L
Linus Torvalds 已提交
1134 1135 1136
			return -EPERM;
	} else {
		dst_pid = nlk->dst_pid;
1137
		dst_group = nlk->dst_group;
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1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
	}

	if (!nlk->pid) {
		err = netlink_autobind(sock);
		if (err)
			goto out;
	}

	err = -EMSGSIZE;
	if (len > sk->sk_sndbuf - 32)
		goto out;
	err = -ENOBUFS;
	skb = alloc_skb(len, GFP_KERNEL);
	if (skb==NULL)
		goto out;

	NETLINK_CB(skb).pid	= nlk->pid;
	NETLINK_CB(skb).dst_pid = dst_pid;
1156
	NETLINK_CB(skb).dst_group = dst_group;
1157
	NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1158
	selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
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	memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));

	/* What can I do? Netlink is asynchronous, so that
	   we will have to save current capabilities to
	   check them, when this message will be delivered
	   to corresponding kernel module.   --ANK (980802)
	 */

	err = -EFAULT;
	if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
		kfree_skb(skb);
		goto out;
	}

	err = security_netlink_send(sk, skb);
	if (err) {
		kfree_skb(skb);
		goto out;
	}

1179
	if (dst_group) {
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Linus Torvalds 已提交
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		atomic_inc(&skb->users);
1181
		netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
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1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226
	}
	err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);

out:
	return err;
}

static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
			   struct msghdr *msg, size_t len,
			   int flags)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct scm_cookie scm;
	struct sock *sk = sock->sk;
	struct netlink_sock *nlk = nlk_sk(sk);
	int noblock = flags&MSG_DONTWAIT;
	size_t copied;
	struct sk_buff *skb;
	int err;

	if (flags&MSG_OOB)
		return -EOPNOTSUPP;

	copied = 0;

	skb = skb_recv_datagram(sk,flags,noblock,&err);
	if (skb==NULL)
		goto out;

	msg->msg_namelen = 0;

	copied = skb->len;
	if (len < copied) {
		msg->msg_flags |= MSG_TRUNC;
		copied = len;
	}

	skb->h.raw = skb->data;
	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	if (msg->msg_name) {
		struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
		addr->nl_family = AF_NETLINK;
		addr->nl_pad    = 0;
		addr->nl_pid	= NETLINK_CB(skb).pid;
1227
		addr->nl_groups	= netlink_group_mask(NETLINK_CB(skb).dst_group);
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1228 1229 1230
		msg->msg_namelen = sizeof(*addr);
	}

1231 1232 1233
	if (nlk->flags & NETLINK_RECV_PKTINFO)
		netlink_cmsg_recv_pktinfo(msg, skb);

L
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1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266
	if (NULL == siocb->scm) {
		memset(&scm, 0, sizeof(scm));
		siocb->scm = &scm;
	}
	siocb->scm->creds = *NETLINK_CREDS(skb);
	skb_free_datagram(sk, skb);

	if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
		netlink_dump(sk);

	scm_recv(sock, msg, siocb->scm, flags);

out:
	netlink_rcv_wake(sk);
	return err ? : copied;
}

static void netlink_data_ready(struct sock *sk, int len)
{
	struct netlink_sock *nlk = nlk_sk(sk);

	if (nlk->data_ready)
		nlk->data_ready(sk, len);
	netlink_rcv_wake(sk);
}

/*
 *	We export these functions to other modules. They provide a 
 *	complete set of kernel non-blocking support for message
 *	queueing.
 */

struct sock *
1267 1268 1269
netlink_kernel_create(int unit, unsigned int groups,
                      void (*input)(struct sock *sk, int len),
                      struct module *module)
L
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{
	struct socket *sock;
	struct sock *sk;
1273
	struct netlink_sock *nlk;
1274
	unsigned long *listeners = NULL;
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	if (!nl_table)
		return NULL;

	if (unit<0 || unit>=MAX_LINKS)
		return NULL;

	if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
		return NULL;

1285
	if (__netlink_create(sock, unit) < 0)
1286
		goto out_sock_release;
1287

1288 1289 1290 1291 1292 1293 1294
	if (groups < 32)
		groups = 32;

	listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
	if (!listeners)
		goto out_sock_release;

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	sk = sock->sk;
	sk->sk_data_ready = netlink_data_ready;
	if (input)
		nlk_sk(sk)->data_ready = input;

1300 1301
	if (netlink_insert(sk, 0))
		goto out_sock_release;
1302

1303 1304
	nlk = nlk_sk(sk);
	nlk->flags |= NETLINK_KERNEL_SOCKET;
1305 1306

	netlink_table_grab();
1307 1308
	nl_table[unit].groups = groups;
	nl_table[unit].listeners = listeners;
1309
	nl_table[unit].module = module;
1310
	nl_table[unit].registered = 1;
1311
	netlink_table_ungrab();
1312 1313 1314

	return sk;

1315
out_sock_release:
1316
	kfree(listeners);
1317
	sock_release(sock);
1318
	return NULL;
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}

void netlink_set_nonroot(int protocol, unsigned int flags)
{ 
	if ((unsigned int)protocol < MAX_LINKS) 
		nl_table[protocol].nl_nonroot = flags;
} 

static void netlink_destroy_callback(struct netlink_callback *cb)
{
	if (cb->skb)
		kfree_skb(cb->skb);
	kfree(cb);
}

/*
 * It looks a bit ugly.
 * It would be better to create kernel thread.
 */

static int netlink_dump(struct sock *sk)
{
	struct netlink_sock *nlk = nlk_sk(sk);
	struct netlink_callback *cb;
	struct sk_buff *skb;
	struct nlmsghdr *nlh;
	int len;
	
	skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	spin_lock(&nlk->cb_lock);

	cb = nlk->cb;
	if (cb == NULL) {
		spin_unlock(&nlk->cb_lock);
		kfree_skb(skb);
		return -EINVAL;
	}

	len = cb->dump(skb, cb);

	if (len > 0) {
		spin_unlock(&nlk->cb_lock);
		skb_queue_tail(&sk->sk_receive_queue, skb);
		sk->sk_data_ready(sk, len);
		return 0;
	}

1369
	nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
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	memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
	skb_queue_tail(&sk->sk_receive_queue, skb);
	sk->sk_data_ready(sk, skb->len);

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	if (cb->done)
		cb->done(cb);
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	nlk->cb = NULL;
	spin_unlock(&nlk->cb_lock);

	netlink_destroy_callback(cb);
	return 0;
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nlmsg_failure:
	return -ENOBUFS;
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}

int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
		       struct nlmsghdr *nlh,
		       int (*dump)(struct sk_buff *skb, struct netlink_callback*),
		       int (*done)(struct netlink_callback*))
{
	struct netlink_callback *cb;
	struct sock *sk;
	struct netlink_sock *nlk;

1395
	cb = kzalloc(sizeof(*cb), GFP_KERNEL);
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	if (cb == NULL)
		return -ENOBUFS;

	cb->dump = dump;
	cb->done = done;
	cb->nlh = nlh;
	atomic_inc(&skb->users);
	cb->skb = skb;

	sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
	if (sk == NULL) {
		netlink_destroy_callback(cb);
		return -ECONNREFUSED;
	}
	nlk = nlk_sk(sk);
	/* A dump is in progress... */
	spin_lock(&nlk->cb_lock);
	if (nlk->cb) {
		spin_unlock(&nlk->cb_lock);
		netlink_destroy_callback(cb);
		sock_put(sk);
		return -EBUSY;
	}
	nlk->cb = cb;
	spin_unlock(&nlk->cb_lock);

	netlink_dump(sk);
	sock_put(sk);
	return 0;
}

void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
{
	struct sk_buff *skb;
	struct nlmsghdr *rep;
	struct nlmsgerr *errmsg;
	int size;

	if (err == 0)
		size = NLMSG_SPACE(sizeof(struct nlmsgerr));
	else
		size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len));

	skb = alloc_skb(size, GFP_KERNEL);
	if (!skb) {
		struct sock *sk;

		sk = netlink_lookup(in_skb->sk->sk_protocol,
				    NETLINK_CB(in_skb).pid);
		if (sk) {
			sk->sk_err = ENOBUFS;
			sk->sk_error_report(sk);
			sock_put(sk);
		}
		return;
	}

	rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1454
			  NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
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	errmsg = NLMSG_DATA(rep);
	errmsg->error = err;
	memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr));
	netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
}

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static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
						     struct nlmsghdr *, int *))
{
	unsigned int total_len;
	struct nlmsghdr *nlh;
	int err;

	while (skb->len >= nlmsg_total_size(0)) {
		nlh = (struct nlmsghdr *) skb->data;

1471
		if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
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			return 0;

		total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len);

		if (cb(skb, nlh, &err) < 0) {
			/* Not an error, but we have to interrupt processing
			 * here. Note: that in this case we do not pull
			 * message from skb, it will be processed later.
			 */
			if (err == 0)
				return -1;
			netlink_ack(skb, nlh, err);
		} else if (nlh->nlmsg_flags & NLM_F_ACK)
			netlink_ack(skb, nlh, 0);

		skb_pull(skb, total_len);
	}

	return 0;
}

/**
 * nelink_run_queue - Process netlink receive queue.
 * @sk: Netlink socket containing the queue
 * @qlen: Place to store queue length upon entry
 * @cb: Callback function invoked for each netlink message found
 *
 * Processes as much as there was in the queue upon entry and invokes
 * a callback function for each netlink message found. The callback
 * function may refuse a message by returning a negative error code
 * but setting the error pointer to 0 in which case this function
 * returns with a qlen != 0.
 *
 * qlen must be initialized to 0 before the initial entry, afterwards
 * the function may be called repeatedly until qlen reaches 0.
 */
void netlink_run_queue(struct sock *sk, unsigned int *qlen,
		       int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
{
	struct sk_buff *skb;

	if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
		*qlen = skb_queue_len(&sk->sk_receive_queue);

	for (; *qlen; (*qlen)--) {
		skb = skb_dequeue(&sk->sk_receive_queue);
		if (netlink_rcv_skb(skb, cb)) {
			if (skb->len)
				skb_queue_head(&sk->sk_receive_queue, skb);
			else {
				kfree_skb(skb);
				(*qlen)--;
			}
			break;
		}

		kfree_skb(skb);
	}
}

/**
 * netlink_queue_skip - Skip netlink message while processing queue.
 * @nlh: Netlink message to be skipped
 * @skb: Socket buffer containing the netlink messages.
 *
 * Pulls the given netlink message off the socket buffer so the next
 * call to netlink_queue_run() will not reconsider the message.
 */
void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
{
	int msglen = NLMSG_ALIGN(nlh->nlmsg_len);

	if (msglen > skb->len)
		msglen = skb->len;

	skb_pull(skb, msglen);
}
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#ifdef CONFIG_PROC_FS
struct nl_seq_iter {
	int link;
	int hash_idx;
};

static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
{
	struct nl_seq_iter *iter = seq->private;
	int i, j;
	struct sock *s;
	struct hlist_node *node;
	loff_t off = 0;

	for (i=0; i<MAX_LINKS; i++) {
		struct nl_pid_hash *hash = &nl_table[i].hash;

		for (j = 0; j <= hash->mask; j++) {
			sk_for_each(s, node, &hash->table[j]) {
				if (off == pos) {
					iter->link = i;
					iter->hash_idx = j;
					return s;
				}
				++off;
			}
		}
	}
	return NULL;
}

static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
{
	read_lock(&nl_table_lock);
	return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct sock *s;
	struct nl_seq_iter *iter;
	int i, j;

	++*pos;

	if (v == SEQ_START_TOKEN)
		return netlink_seq_socket_idx(seq, 0);
		
	s = sk_next(v);
	if (s)
		return s;

	iter = seq->private;
	i = iter->link;
	j = iter->hash_idx + 1;

	do {
		struct nl_pid_hash *hash = &nl_table[i].hash;

		for (; j <= hash->mask; j++) {
			s = sk_head(&hash->table[j]);
			if (s) {
				iter->link = i;
				iter->hash_idx = j;
				return s;
			}
		}

		j = 0;
	} while (++i < MAX_LINKS);

	return NULL;
}

static void netlink_seq_stop(struct seq_file *seq, void *v)
{
	read_unlock(&nl_table_lock);
}


static int netlink_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_puts(seq,
			 "sk       Eth Pid    Groups   "
			 "Rmem     Wmem     Dump     Locks\n");
	else {
		struct sock *s = v;
		struct netlink_sock *nlk = nlk_sk(s);

		seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
			   s,
			   s->sk_protocol,
			   nlk->pid,
1644
			   nlk->groups ? (u32)nlk->groups[0] : 0,
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			   atomic_read(&s->sk_rmem_alloc),
			   atomic_read(&s->sk_wmem_alloc),
			   nlk->cb,
			   atomic_read(&s->sk_refcnt)
			);

	}
	return 0;
}

static struct seq_operations netlink_seq_ops = {
	.start  = netlink_seq_start,
	.next   = netlink_seq_next,
	.stop   = netlink_seq_stop,
	.show   = netlink_seq_show,
};


static int netlink_seq_open(struct inode *inode, struct file *file)
{
	struct seq_file *seq;
	struct nl_seq_iter *iter;
	int err;

1669
	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
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	if (!iter)
		return -ENOMEM;

	err = seq_open(file, &netlink_seq_ops);
	if (err) {
		kfree(iter);
		return err;
	}

	seq = file->private_data;
	seq->private = iter;
	return 0;
}

static struct file_operations netlink_seq_fops = {
	.owner		= THIS_MODULE,
	.open		= netlink_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release_private,
};

#endif

int netlink_register_notifier(struct notifier_block *nb)
{
1696
	return atomic_notifier_chain_register(&netlink_chain, nb);
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}

int netlink_unregister_notifier(struct notifier_block *nb)
{
1701
	return atomic_notifier_chain_unregister(&netlink_chain, nb);
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}
                
1704
static const struct proto_ops netlink_ops = {
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	.family =	PF_NETLINK,
	.owner =	THIS_MODULE,
	.release =	netlink_release,
	.bind =		netlink_bind,
	.connect =	netlink_connect,
	.socketpair =	sock_no_socketpair,
	.accept =	sock_no_accept,
	.getname =	netlink_getname,
	.poll =		datagram_poll,
	.ioctl =	sock_no_ioctl,
	.listen =	sock_no_listen,
	.shutdown =	sock_no_shutdown,
1717 1718
	.setsockopt =	netlink_setsockopt,
	.getsockopt =	netlink_getsockopt,
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	.sendmsg =	netlink_sendmsg,
	.recvmsg =	netlink_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
};

static struct net_proto_family netlink_family_ops = {
	.family = PF_NETLINK,
	.create = netlink_create,
	.owner	= THIS_MODULE,	/* for consistency 8) */
};

extern void netlink_skb_parms_too_large(void);

static int __init netlink_proto_init(void)
{
	struct sk_buff *dummy_skb;
	int i;
	unsigned long max;
	unsigned int order;
	int err = proto_register(&netlink_proto, 0);

	if (err != 0)
		goto out;

	if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb))
		netlink_skb_parms_too_large();

1747
	nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
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	if (!nl_table) {
enomem:
		printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n");
		return -ENOMEM;
	}

	if (num_physpages >= (128 * 1024))
		max = num_physpages >> (21 - PAGE_SHIFT);
	else
		max = num_physpages >> (23 - PAGE_SHIFT);

	order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
	max = (1UL << order) / sizeof(struct hlist_head);
	order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;

	for (i = 0; i < MAX_LINKS; i++) {
		struct nl_pid_hash *hash = &nl_table[i].hash;

		hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
		if (!hash->table) {
			while (i-- > 0)
				nl_pid_hash_free(nl_table[i].hash.table,
						 1 * sizeof(*hash->table));
			kfree(nl_table);
			goto enomem;
		}
		memset(hash->table, 0, 1 * sizeof(*hash->table));
		hash->max_shift = order;
		hash->shift = 0;
		hash->mask = 0;
		hash->rehash_time = jiffies;
	}

	sock_register(&netlink_family_ops);
#ifdef CONFIG_PROC_FS
	proc_net_fops_create("netlink", 0, &netlink_seq_fops);
#endif
	/* The netlink device handler may be needed early. */ 
	rtnetlink_init();
out:
	return err;
}

core_initcall(netlink_proto_init);

EXPORT_SYMBOL(netlink_ack);
1794 1795
EXPORT_SYMBOL(netlink_run_queue);
EXPORT_SYMBOL(netlink_queue_skip);
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EXPORT_SYMBOL(netlink_broadcast);
EXPORT_SYMBOL(netlink_dump_start);
EXPORT_SYMBOL(netlink_kernel_create);
EXPORT_SYMBOL(netlink_register_notifier);
EXPORT_SYMBOL(netlink_set_err);
EXPORT_SYMBOL(netlink_set_nonroot);
EXPORT_SYMBOL(netlink_unicast);
EXPORT_SYMBOL(netlink_unregister_notifier);