1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * NETLINK      Kernel-user communication protocol.
   4 *
   5 * 		Authors:	Alan Cox <alan@lxorguk.ukuu.org.uk>
   6 * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
   7 * 				Patrick McHardy <kaber@trash.net>
   8 *
 
 
 
 
 
   9 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
  10 *                               added netlink_proto_exit
  11 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
  12 * 				 use nlk_sk, as sk->protinfo is on a diet 8)
  13 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
  14 * 				 - inc module use count of module that owns
  15 * 				   the kernel socket in case userspace opens
  16 * 				   socket of same protocol
  17 * 				 - remove all module support, since netlink is
  18 * 				   mandatory if CONFIG_NET=y these days
  19 */
  20
  21#include <linux/module.h>
  22
  23#include <linux/capability.h>
  24#include <linux/kernel.h>
  25#include <linux/init.h>
  26#include <linux/signal.h>
  27#include <linux/sched.h>
  28#include <linux/errno.h>
  29#include <linux/string.h>
  30#include <linux/stat.h>
  31#include <linux/socket.h>
  32#include <linux/un.h>
  33#include <linux/fcntl.h>
  34#include <linux/termios.h>
  35#include <linux/sockios.h>
  36#include <linux/net.h>
  37#include <linux/fs.h>
  38#include <linux/slab.h>
  39#include <linux/uaccess.h>
  40#include <linux/skbuff.h>
  41#include <linux/netdevice.h>
  42#include <linux/rtnetlink.h>
  43#include <linux/proc_fs.h>
  44#include <linux/seq_file.h>
  45#include <linux/notifier.h>
  46#include <linux/security.h>
  47#include <linux/jhash.h>
  48#include <linux/jiffies.h>
  49#include <linux/random.h>
  50#include <linux/bitops.h>
  51#include <linux/mm.h>
  52#include <linux/types.h>
  53#include <linux/audit.h>
  54#include <linux/mutex.h>
  55#include <linux/vmalloc.h>
  56#include <linux/if_arp.h>
  57#include <linux/rhashtable.h>
  58#include <asm/cacheflush.h>
  59#include <linux/hash.h>
  60#include <linux/genetlink.h>
  61#include <linux/net_namespace.h>
  62#include <linux/nospec.h>
  63
  64#include <net/net_namespace.h>
  65#include <net/netns/generic.h>
  66#include <net/sock.h>
  67#include <net/scm.h>
  68#include <net/netlink.h>
  69
  70#include "af_netlink.h"
  71
  72struct listeners {
  73	struct rcu_head		rcu;
  74	unsigned long		masks[0];
  75};
  76
  77/* state bits */
  78#define NETLINK_S_CONGESTED		0x0
  79
  80static inline int netlink_is_kernel(struct sock *sk)
  81{
  82	return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
  83}
  84
  85struct netlink_table *nl_table __read_mostly;
  86EXPORT_SYMBOL_GPL(nl_table);
  87
  88static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
  89
  90static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
  91
  92static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
  93	"nlk_cb_mutex-ROUTE",
  94	"nlk_cb_mutex-1",
  95	"nlk_cb_mutex-USERSOCK",
  96	"nlk_cb_mutex-FIREWALL",
  97	"nlk_cb_mutex-SOCK_DIAG",
  98	"nlk_cb_mutex-NFLOG",
  99	"nlk_cb_mutex-XFRM",
 100	"nlk_cb_mutex-SELINUX",
 101	"nlk_cb_mutex-ISCSI",
 102	"nlk_cb_mutex-AUDIT",
 103	"nlk_cb_mutex-FIB_LOOKUP",
 104	"nlk_cb_mutex-CONNECTOR",
 105	"nlk_cb_mutex-NETFILTER",
 106	"nlk_cb_mutex-IP6_FW",
 107	"nlk_cb_mutex-DNRTMSG",
 108	"nlk_cb_mutex-KOBJECT_UEVENT",
 109	"nlk_cb_mutex-GENERIC",
 110	"nlk_cb_mutex-17",
 111	"nlk_cb_mutex-SCSITRANSPORT",
 112	"nlk_cb_mutex-ECRYPTFS",
 113	"nlk_cb_mutex-RDMA",
 114	"nlk_cb_mutex-CRYPTO",
 115	"nlk_cb_mutex-SMC",
 116	"nlk_cb_mutex-23",
 117	"nlk_cb_mutex-24",
 118	"nlk_cb_mutex-25",
 119	"nlk_cb_mutex-26",
 120	"nlk_cb_mutex-27",
 121	"nlk_cb_mutex-28",
 122	"nlk_cb_mutex-29",
 123	"nlk_cb_mutex-30",
 124	"nlk_cb_mutex-31",
 125	"nlk_cb_mutex-MAX_LINKS"
 126};
 127
 128static int netlink_dump(struct sock *sk);
 129
 130/* nl_table locking explained:
 131 * Lookup and traversal are protected with an RCU read-side lock. Insertion
 132 * and removal are protected with per bucket lock while using RCU list
 133 * modification primitives and may run in parallel to RCU protected lookups.
 134 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
 135 * been acquired * either during or after the socket has been removed from
 136 * the list and after an RCU grace period.
 137 */
 138DEFINE_RWLOCK(nl_table_lock);
 139EXPORT_SYMBOL_GPL(nl_table_lock);
 140static atomic_t nl_table_users = ATOMIC_INIT(0);
 141
 142#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
 143
 144static BLOCKING_NOTIFIER_HEAD(netlink_chain);
 145
 146
 147static const struct rhashtable_params netlink_rhashtable_params;
 148
 149static inline u32 netlink_group_mask(u32 group)
 150{
 151	return group ? 1 << (group - 1) : 0;
 152}
 153
 154static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
 155					   gfp_t gfp_mask)
 156{
 157	unsigned int len = skb_end_offset(skb);
 158	struct sk_buff *new;
 159
 160	new = alloc_skb(len, gfp_mask);
 161	if (new == NULL)
 162		return NULL;
 163
 164	NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
 165	NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
 166	NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
 167
 168	skb_put_data(new, skb->data, len);
 169	return new;
 170}
 171
 172static unsigned int netlink_tap_net_id;
 173
 174struct netlink_tap_net {
 175	struct list_head netlink_tap_all;
 176	struct mutex netlink_tap_lock;
 177};
 178
 179int netlink_add_tap(struct netlink_tap *nt)
 180{
 181	struct net *net = dev_net(nt->dev);
 182	struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
 183
 184	if (unlikely(nt->dev->type != ARPHRD_NETLINK))
 185		return -EINVAL;
 186
 187	mutex_lock(&nn->netlink_tap_lock);
 188	list_add_rcu(&nt->list, &nn->netlink_tap_all);
 189	mutex_unlock(&nn->netlink_tap_lock);
 190
 191	__module_get(nt->module);
 192
 193	return 0;
 194}
 195EXPORT_SYMBOL_GPL(netlink_add_tap);
 196
 197static int __netlink_remove_tap(struct netlink_tap *nt)
 198{
 199	struct net *net = dev_net(nt->dev);
 200	struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
 201	bool found = false;
 202	struct netlink_tap *tmp;
 203
 204	mutex_lock(&nn->netlink_tap_lock);
 205
 206	list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
 207		if (nt == tmp) {
 208			list_del_rcu(&nt->list);
 209			found = true;
 210			goto out;
 211		}
 212	}
 213
 214	pr_warn("__netlink_remove_tap: %p not found\n", nt);
 215out:
 216	mutex_unlock(&nn->netlink_tap_lock);
 217
 218	if (found)
 219		module_put(nt->module);
 220
 221	return found ? 0 : -ENODEV;
 222}
 223
 224int netlink_remove_tap(struct netlink_tap *nt)
 225{
 226	int ret;
 227
 228	ret = __netlink_remove_tap(nt);
 229	synchronize_net();
 230
 231	return ret;
 232}
 233EXPORT_SYMBOL_GPL(netlink_remove_tap);
 234
 235static __net_init int netlink_tap_init_net(struct net *net)
 236{
 237	struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
 238
 239	INIT_LIST_HEAD(&nn->netlink_tap_all);
 240	mutex_init(&nn->netlink_tap_lock);
 241	return 0;
 242}
 243
 
 
 
 
 244static struct pernet_operations netlink_tap_net_ops = {
 245	.init = netlink_tap_init_net,
 
 246	.id   = &netlink_tap_net_id,
 247	.size = sizeof(struct netlink_tap_net),
 248};
 249
 250static bool netlink_filter_tap(const struct sk_buff *skb)
 251{
 252	struct sock *sk = skb->sk;
 253
 254	/* We take the more conservative approach and
 255	 * whitelist socket protocols that may pass.
 256	 */
 257	switch (sk->sk_protocol) {
 258	case NETLINK_ROUTE:
 259	case NETLINK_USERSOCK:
 260	case NETLINK_SOCK_DIAG:
 261	case NETLINK_NFLOG:
 262	case NETLINK_XFRM:
 263	case NETLINK_FIB_LOOKUP:
 264	case NETLINK_NETFILTER:
 265	case NETLINK_GENERIC:
 266		return true;
 267	}
 268
 269	return false;
 270}
 271
 272static int __netlink_deliver_tap_skb(struct sk_buff *skb,
 273				     struct net_device *dev)
 274{
 275	struct sk_buff *nskb;
 276	struct sock *sk = skb->sk;
 277	int ret = -ENOMEM;
 278
 279	if (!net_eq(dev_net(dev), sock_net(sk)))
 280		return 0;
 281
 282	dev_hold(dev);
 283
 284	if (is_vmalloc_addr(skb->head))
 285		nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
 286	else
 287		nskb = skb_clone(skb, GFP_ATOMIC);
 288	if (nskb) {
 289		nskb->dev = dev;
 290		nskb->protocol = htons((u16) sk->sk_protocol);
 291		nskb->pkt_type = netlink_is_kernel(sk) ?
 292				 PACKET_KERNEL : PACKET_USER;
 293		skb_reset_network_header(nskb);
 294		ret = dev_queue_xmit(nskb);
 295		if (unlikely(ret > 0))
 296			ret = net_xmit_errno(ret);
 297	}
 298
 299	dev_put(dev);
 300	return ret;
 301}
 302
 303static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
 304{
 305	int ret;
 306	struct netlink_tap *tmp;
 307
 308	if (!netlink_filter_tap(skb))
 309		return;
 310
 311	list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
 312		ret = __netlink_deliver_tap_skb(skb, tmp->dev);
 313		if (unlikely(ret))
 314			break;
 315	}
 316}
 317
 318static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
 319{
 320	struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
 321
 322	rcu_read_lock();
 323
 324	if (unlikely(!list_empty(&nn->netlink_tap_all)))
 325		__netlink_deliver_tap(skb, nn);
 326
 327	rcu_read_unlock();
 328}
 329
 330static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
 331				       struct sk_buff *skb)
 332{
 333	if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
 334		netlink_deliver_tap(sock_net(dst), skb);
 335}
 336
 337static void netlink_overrun(struct sock *sk)
 338{
 339	struct netlink_sock *nlk = nlk_sk(sk);
 340
 341	if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
 342		if (!test_and_set_bit(NETLINK_S_CONGESTED,
 343				      &nlk_sk(sk)->state)) {
 344			sk->sk_err = ENOBUFS;
 345			sk->sk_error_report(sk);
 346		}
 347	}
 348	atomic_inc(&sk->sk_drops);
 349}
 350
 351static void netlink_rcv_wake(struct sock *sk)
 352{
 353	struct netlink_sock *nlk = nlk_sk(sk);
 354
 355	if (skb_queue_empty(&sk->sk_receive_queue))
 356		clear_bit(NETLINK_S_CONGESTED, &nlk->state);
 357	if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
 358		wake_up_interruptible(&nlk->wait);
 359}
 360
 361static void netlink_skb_destructor(struct sk_buff *skb)
 362{
 363	if (is_vmalloc_addr(skb->head)) {
 364		if (!skb->cloned ||
 365		    !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
 366			vfree(skb->head);
 367
 368		skb->head = NULL;
 369	}
 370	if (skb->sk != NULL)
 371		sock_rfree(skb);
 372}
 373
 374static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
 375{
 376	WARN_ON(skb->sk != NULL);
 377	skb->sk = sk;
 378	skb->destructor = netlink_skb_destructor;
 379	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
 380	sk_mem_charge(sk, skb->truesize);
 381}
 382
 383static void netlink_sock_destruct(struct sock *sk)
 384{
 385	struct netlink_sock *nlk = nlk_sk(sk);
 386
 387	if (nlk->cb_running) {
 388		if (nlk->cb.done)
 389			nlk->cb.done(&nlk->cb);
 390		module_put(nlk->cb.module);
 391		kfree_skb(nlk->cb.skb);
 392	}
 393
 394	skb_queue_purge(&sk->sk_receive_queue);
 395
 396	if (!sock_flag(sk, SOCK_DEAD)) {
 397		printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
 398		return;
 399	}
 400
 401	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
 402	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
 403	WARN_ON(nlk_sk(sk)->groups);
 404}
 405
 406static void netlink_sock_destruct_work(struct work_struct *work)
 407{
 408	struct netlink_sock *nlk = container_of(work, struct netlink_sock,
 409						work);
 410
 411	sk_free(&nlk->sk);
 412}
 413
 414/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
 415 * SMP. Look, when several writers sleep and reader wakes them up, all but one
 416 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
 417 * this, _but_ remember, it adds useless work on UP machines.
 418 */
 419
 420void netlink_table_grab(void)
 421	__acquires(nl_table_lock)
 422{
 423	might_sleep();
 424
 425	write_lock_irq(&nl_table_lock);
 426
 427	if (atomic_read(&nl_table_users)) {
 428		DECLARE_WAITQUEUE(wait, current);
 429
 430		add_wait_queue_exclusive(&nl_table_wait, &wait);
 431		for (;;) {
 432			set_current_state(TASK_UNINTERRUPTIBLE);
 433			if (atomic_read(&nl_table_users) == 0)
 434				break;
 435			write_unlock_irq(&nl_table_lock);
 436			schedule();
 437			write_lock_irq(&nl_table_lock);
 438		}
 439
 440		__set_current_state(TASK_RUNNING);
 441		remove_wait_queue(&nl_table_wait, &wait);
 442	}
 443}
 444
 445void netlink_table_ungrab(void)
 446	__releases(nl_table_lock)
 447{
 448	write_unlock_irq(&nl_table_lock);
 449	wake_up(&nl_table_wait);
 450}
 451
 452static inline void
 453netlink_lock_table(void)
 454{
 455	/* read_lock() synchronizes us to netlink_table_grab */
 456
 457	read_lock(&nl_table_lock);
 458	atomic_inc(&nl_table_users);
 459	read_unlock(&nl_table_lock);
 460}
 461
 462static inline void
 463netlink_unlock_table(void)
 464{
 465	if (atomic_dec_and_test(&nl_table_users))
 466		wake_up(&nl_table_wait);
 467}
 468
 469struct netlink_compare_arg
 470{
 471	possible_net_t pnet;
 472	u32 portid;
 473};
 474
 475/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
 476#define netlink_compare_arg_len \
 477	(offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
 478
 479static inline int netlink_compare(struct rhashtable_compare_arg *arg,
 480				  const void *ptr)
 481{
 482	const struct netlink_compare_arg *x = arg->key;
 483	const struct netlink_sock *nlk = ptr;
 484
 485	return nlk->portid != x->portid ||
 486	       !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
 487}
 488
 489static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
 490				     struct net *net, u32 portid)
 491{
 492	memset(arg, 0, sizeof(*arg));
 493	write_pnet(&arg->pnet, net);
 494	arg->portid = portid;
 495}
 496
 497static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
 498				     struct net *net)
 499{
 500	struct netlink_compare_arg arg;
 501
 502	netlink_compare_arg_init(&arg, net, portid);
 503	return rhashtable_lookup_fast(&table->hash, &arg,
 504				      netlink_rhashtable_params);
 505}
 506
 507static int __netlink_insert(struct netlink_table *table, struct sock *sk)
 508{
 509	struct netlink_compare_arg arg;
 510
 511	netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
 512	return rhashtable_lookup_insert_key(&table->hash, &arg,
 513					    &nlk_sk(sk)->node,
 514					    netlink_rhashtable_params);
 515}
 516
 517static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
 518{
 519	struct netlink_table *table = &nl_table[protocol];
 520	struct sock *sk;
 521
 522	rcu_read_lock();
 523	sk = __netlink_lookup(table, portid, net);
 524	if (sk)
 525		sock_hold(sk);
 526	rcu_read_unlock();
 527
 528	return sk;
 529}
 530
 531static const struct proto_ops netlink_ops;
 532
 533static void
 534netlink_update_listeners(struct sock *sk)
 535{
 536	struct netlink_table *tbl = &nl_table[sk->sk_protocol];
 537	unsigned long mask;
 538	unsigned int i;
 539	struct listeners *listeners;
 540
 541	listeners = nl_deref_protected(tbl->listeners);
 542	if (!listeners)
 543		return;
 544
 545	for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
 546		mask = 0;
 547		sk_for_each_bound(sk, &tbl->mc_list) {
 548			if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
 549				mask |= nlk_sk(sk)->groups[i];
 550		}
 551		listeners->masks[i] = mask;
 552	}
 553	/* this function is only called with the netlink table "grabbed", which
 554	 * makes sure updates are visible before bind or setsockopt return. */
 555}
 556
 557static int netlink_insert(struct sock *sk, u32 portid)
 558{
 559	struct netlink_table *table = &nl_table[sk->sk_protocol];
 560	int err;
 561
 562	lock_sock(sk);
 563
 564	err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
 565	if (nlk_sk(sk)->bound)
 566		goto err;
 567
 
 
 
 
 
 568	nlk_sk(sk)->portid = portid;
 569	sock_hold(sk);
 570
 571	err = __netlink_insert(table, sk);
 572	if (err) {
 573		/* In case the hashtable backend returns with -EBUSY
 574		 * from here, it must not escape to the caller.
 575		 */
 576		if (unlikely(err == -EBUSY))
 577			err = -EOVERFLOW;
 578		if (err == -EEXIST)
 579			err = -EADDRINUSE;
 580		sock_put(sk);
 581		goto err;
 582	}
 583
 584	/* We need to ensure that the socket is hashed and visible. */
 585	smp_wmb();
 586	nlk_sk(sk)->bound = portid;
 587
 588err:
 589	release_sock(sk);
 590	return err;
 591}
 592
 593static void netlink_remove(struct sock *sk)
 594{
 595	struct netlink_table *table;
 596
 597	table = &nl_table[sk->sk_protocol];
 598	if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
 599				    netlink_rhashtable_params)) {
 600		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
 601		__sock_put(sk);
 602	}
 603
 604	netlink_table_grab();
 605	if (nlk_sk(sk)->subscriptions) {
 606		__sk_del_bind_node(sk);
 607		netlink_update_listeners(sk);
 608	}
 609	if (sk->sk_protocol == NETLINK_GENERIC)
 610		atomic_inc(&genl_sk_destructing_cnt);
 611	netlink_table_ungrab();
 612}
 613
 614static struct proto netlink_proto = {
 615	.name	  = "NETLINK",
 616	.owner	  = THIS_MODULE,
 617	.obj_size = sizeof(struct netlink_sock),
 618};
 619
 620static int __netlink_create(struct net *net, struct socket *sock,
 621			    struct mutex *cb_mutex, int protocol,
 622			    int kern)
 623{
 624	struct sock *sk;
 625	struct netlink_sock *nlk;
 626
 627	sock->ops = &netlink_ops;
 628
 629	sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
 630	if (!sk)
 631		return -ENOMEM;
 632
 633	sock_init_data(sock, sk);
 634
 635	nlk = nlk_sk(sk);
 636	if (cb_mutex) {
 637		nlk->cb_mutex = cb_mutex;
 638	} else {
 639		nlk->cb_mutex = &nlk->cb_def_mutex;
 640		mutex_init(nlk->cb_mutex);
 641		lockdep_set_class_and_name(nlk->cb_mutex,
 642					   nlk_cb_mutex_keys + protocol,
 643					   nlk_cb_mutex_key_strings[protocol]);
 644	}
 645	init_waitqueue_head(&nlk->wait);
 646
 647	sk->sk_destruct = netlink_sock_destruct;
 648	sk->sk_protocol = protocol;
 649	return 0;
 650}
 651
 652static int netlink_create(struct net *net, struct socket *sock, int protocol,
 653			  int kern)
 654{
 655	struct module *module = NULL;
 656	struct mutex *cb_mutex;
 657	struct netlink_sock *nlk;
 658	int (*bind)(struct net *net, int group);
 659	void (*unbind)(struct net *net, int group);
 660	int err = 0;
 661
 662	sock->state = SS_UNCONNECTED;
 663
 664	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
 665		return -ESOCKTNOSUPPORT;
 666
 667	if (protocol < 0 || protocol >= MAX_LINKS)
 668		return -EPROTONOSUPPORT;
 669	protocol = array_index_nospec(protocol, MAX_LINKS);
 670
 671	netlink_lock_table();
 672#ifdef CONFIG_MODULES
 673	if (!nl_table[protocol].registered) {
 674		netlink_unlock_table();
 675		request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
 676		netlink_lock_table();
 677	}
 678#endif
 679	if (nl_table[protocol].registered &&
 680	    try_module_get(nl_table[protocol].module))
 681		module = nl_table[protocol].module;
 682	else
 683		err = -EPROTONOSUPPORT;
 684	cb_mutex = nl_table[protocol].cb_mutex;
 685	bind = nl_table[protocol].bind;
 686	unbind = nl_table[protocol].unbind;
 687	netlink_unlock_table();
 688
 689	if (err < 0)
 690		goto out;
 691
 692	err = __netlink_create(net, sock, cb_mutex, protocol, kern);
 693	if (err < 0)
 694		goto out_module;
 695
 696	local_bh_disable();
 697	sock_prot_inuse_add(net, &netlink_proto, 1);
 698	local_bh_enable();
 699
 700	nlk = nlk_sk(sock->sk);
 701	nlk->module = module;
 702	nlk->netlink_bind = bind;
 703	nlk->netlink_unbind = unbind;
 704out:
 705	return err;
 706
 707out_module:
 708	module_put(module);
 709	goto out;
 710}
 711
 712static void deferred_put_nlk_sk(struct rcu_head *head)
 713{
 714	struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
 715	struct sock *sk = &nlk->sk;
 716
 717	kfree(nlk->groups);
 718	nlk->groups = NULL;
 719
 720	if (!refcount_dec_and_test(&sk->sk_refcnt))
 721		return;
 722
 723	if (nlk->cb_running && nlk->cb.done) {
 724		INIT_WORK(&nlk->work, netlink_sock_destruct_work);
 725		schedule_work(&nlk->work);
 726		return;
 727	}
 728
 729	sk_free(sk);
 730}
 731
 732static int netlink_release(struct socket *sock)
 733{
 734	struct sock *sk = sock->sk;
 735	struct netlink_sock *nlk;
 736
 737	if (!sk)
 738		return 0;
 739
 740	netlink_remove(sk);
 741	sock_orphan(sk);
 742	nlk = nlk_sk(sk);
 743
 744	/*
 745	 * OK. Socket is unlinked, any packets that arrive now
 746	 * will be purged.
 747	 */
 748
 749	/* must not acquire netlink_table_lock in any way again before unbind
 750	 * and notifying genetlink is done as otherwise it might deadlock
 751	 */
 752	if (nlk->netlink_unbind) {
 753		int i;
 754
 755		for (i = 0; i < nlk->ngroups; i++)
 756			if (test_bit(i, nlk->groups))
 757				nlk->netlink_unbind(sock_net(sk), i + 1);
 758	}
 759	if (sk->sk_protocol == NETLINK_GENERIC &&
 760	    atomic_dec_return(&genl_sk_destructing_cnt) == 0)
 761		wake_up(&genl_sk_destructing_waitq);
 762
 763	sock->sk = NULL;
 764	wake_up_interruptible_all(&nlk->wait);
 765
 766	skb_queue_purge(&sk->sk_write_queue);
 767
 768	if (nlk->portid && nlk->bound) {
 769		struct netlink_notify n = {
 770						.net = sock_net(sk),
 771						.protocol = sk->sk_protocol,
 772						.portid = nlk->portid,
 773					  };
 774		blocking_notifier_call_chain(&netlink_chain,
 775				NETLINK_URELEASE, &n);
 776	}
 777
 778	module_put(nlk->module);
 779
 780	if (netlink_is_kernel(sk)) {
 781		netlink_table_grab();
 782		BUG_ON(nl_table[sk->sk_protocol].registered == 0);
 783		if (--nl_table[sk->sk_protocol].registered == 0) {
 784			struct listeners *old;
 785
 786			old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
 787			RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
 788			kfree_rcu(old, rcu);
 789			nl_table[sk->sk_protocol].module = NULL;
 790			nl_table[sk->sk_protocol].bind = NULL;
 791			nl_table[sk->sk_protocol].unbind = NULL;
 792			nl_table[sk->sk_protocol].flags = 0;
 793			nl_table[sk->sk_protocol].registered = 0;
 794		}
 795		netlink_table_ungrab();
 796	}
 797
 798	local_bh_disable();
 799	sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
 800	local_bh_enable();
 801	call_rcu(&nlk->rcu, deferred_put_nlk_sk);
 802	return 0;
 803}
 804
 805static int netlink_autobind(struct socket *sock)
 806{
 807	struct sock *sk = sock->sk;
 808	struct net *net = sock_net(sk);
 809	struct netlink_table *table = &nl_table[sk->sk_protocol];
 810	s32 portid = task_tgid_vnr(current);
 811	int err;
 812	s32 rover = -4096;
 813	bool ok;
 814
 815retry:
 816	cond_resched();
 817	rcu_read_lock();
 818	ok = !__netlink_lookup(table, portid, net);
 819	rcu_read_unlock();
 820	if (!ok) {
 821		/* Bind collision, search negative portid values. */
 822		if (rover == -4096)
 823			/* rover will be in range [S32_MIN, -4097] */
 824			rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
 825		else if (rover >= -4096)
 826			rover = -4097;
 827		portid = rover--;
 828		goto retry;
 829	}
 830
 831	err = netlink_insert(sk, portid);
 832	if (err == -EADDRINUSE)
 833		goto retry;
 834
 835	/* If 2 threads race to autobind, that is fine.  */
 836	if (err == -EBUSY)
 837		err = 0;
 838
 839	return err;
 840}
 841
 842/**
 843 * __netlink_ns_capable - General netlink message capability test
 844 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
 845 * @user_ns: The user namespace of the capability to use
 846 * @cap: The capability to use
 847 *
 848 * Test to see if the opener of the socket we received the message
 849 * from had when the netlink socket was created and the sender of the
 850 * message has has the capability @cap in the user namespace @user_ns.
 851 */
 852bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
 853			struct user_namespace *user_ns, int cap)
 854{
 855	return ((nsp->flags & NETLINK_SKB_DST) ||
 856		file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
 857		ns_capable(user_ns, cap);
 858}
 859EXPORT_SYMBOL(__netlink_ns_capable);
 860
 861/**
 862 * netlink_ns_capable - General netlink message capability test
 863 * @skb: socket buffer holding a netlink command from userspace
 864 * @user_ns: The user namespace of the capability to use
 865 * @cap: The capability to use
 866 *
 867 * Test to see if the opener of the socket we received the message
 868 * from had when the netlink socket was created and the sender of the
 869 * message has has the capability @cap in the user namespace @user_ns.
 870 */
 871bool netlink_ns_capable(const struct sk_buff *skb,
 872			struct user_namespace *user_ns, int cap)
 873{
 874	return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
 875}
 876EXPORT_SYMBOL(netlink_ns_capable);
 877
 878/**
 879 * netlink_capable - Netlink global message capability test
 880 * @skb: socket buffer holding a netlink command from userspace
 881 * @cap: The capability to use
 882 *
 883 * Test to see if the opener of the socket we received the message
 884 * from had when the netlink socket was created and the sender of the
 885 * message has has the capability @cap in all user namespaces.
 886 */
 887bool netlink_capable(const struct sk_buff *skb, int cap)
 888{
 889	return netlink_ns_capable(skb, &init_user_ns, cap);
 890}
 891EXPORT_SYMBOL(netlink_capable);
 892
 893/**
 894 * netlink_net_capable - Netlink network namespace message capability test
 895 * @skb: socket buffer holding a netlink command from userspace
 896 * @cap: The capability to use
 897 *
 898 * Test to see if the opener of the socket we received the message
 899 * from had when the netlink socket was created and the sender of the
 900 * message has has the capability @cap over the network namespace of
 901 * the socket we received the message from.
 902 */
 903bool netlink_net_capable(const struct sk_buff *skb, int cap)
 904{
 905	return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
 906}
 907EXPORT_SYMBOL(netlink_net_capable);
 908
 909static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
 910{
 911	return (nl_table[sock->sk->sk_protocol].flags & flag) ||
 912		ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
 913}
 914
 915static void
 916netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
 917{
 918	struct netlink_sock *nlk = nlk_sk(sk);
 919
 920	if (nlk->subscriptions && !subscriptions)
 921		__sk_del_bind_node(sk);
 922	else if (!nlk->subscriptions && subscriptions)
 923		sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
 924	nlk->subscriptions = subscriptions;
 925}
 926
 927static int netlink_realloc_groups(struct sock *sk)
 928{
 929	struct netlink_sock *nlk = nlk_sk(sk);
 930	unsigned int groups;
 931	unsigned long *new_groups;
 932	int err = 0;
 933
 934	netlink_table_grab();
 935
 936	groups = nl_table[sk->sk_protocol].groups;
 937	if (!nl_table[sk->sk_protocol].registered) {
 938		err = -ENOENT;
 939		goto out_unlock;
 940	}
 941
 942	if (nlk->ngroups >= groups)
 943		goto out_unlock;
 944
 945	new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
 946	if (new_groups == NULL) {
 947		err = -ENOMEM;
 948		goto out_unlock;
 949	}
 950	memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
 951	       NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
 952
 953	nlk->groups = new_groups;
 954	nlk->ngroups = groups;
 955 out_unlock:
 956	netlink_table_ungrab();
 957	return err;
 958}
 959
 960static void netlink_undo_bind(int group, long unsigned int groups,
 961			      struct sock *sk)
 962{
 963	struct netlink_sock *nlk = nlk_sk(sk);
 964	int undo;
 965
 966	if (!nlk->netlink_unbind)
 967		return;
 968
 969	for (undo = 0; undo < group; undo++)
 970		if (test_bit(undo, &groups))
 971			nlk->netlink_unbind(sock_net(sk), undo + 1);
 972}
 973
 974static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 975			int addr_len)
 976{
 977	struct sock *sk = sock->sk;
 978	struct net *net = sock_net(sk);
 979	struct netlink_sock *nlk = nlk_sk(sk);
 980	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
 981	int err = 0;
 982	unsigned long groups;
 983	bool bound;
 984
 985	if (addr_len < sizeof(struct sockaddr_nl))
 986		return -EINVAL;
 987
 988	if (nladdr->nl_family != AF_NETLINK)
 989		return -EINVAL;
 990	groups = nladdr->nl_groups;
 991
 992	/* Only superuser is allowed to listen multicasts */
 993	if (groups) {
 994		if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
 995			return -EPERM;
 996		err = netlink_realloc_groups(sk);
 997		if (err)
 998			return err;
 999	}
1000
1001	if (nlk->ngroups < BITS_PER_LONG)
1002		groups &= (1UL << nlk->ngroups) - 1;
1003
1004	bound = nlk->bound;
1005	if (bound) {
1006		/* Ensure nlk->portid is up-to-date. */
1007		smp_rmb();
1008
1009		if (nladdr->nl_pid != nlk->portid)
1010			return -EINVAL;
1011	}
1012
1013	netlink_lock_table();
1014	if (nlk->netlink_bind && groups) {
1015		int group;
1016
1017		for (group = 0; group < nlk->ngroups; group++) {
1018			if (!test_bit(group, &groups))
1019				continue;
1020			err = nlk->netlink_bind(net, group + 1);
1021			if (!err)
1022				continue;
1023			netlink_undo_bind(group, groups, sk);
1024			goto unlock;
1025		}
1026	}
1027
1028	/* No need for barriers here as we return to user-space without
1029	 * using any of the bound attributes.
1030	 */
1031	if (!bound) {
1032		err = nladdr->nl_pid ?
1033			netlink_insert(sk, nladdr->nl_pid) :
1034			netlink_autobind(sock);
1035		if (err) {
1036			netlink_undo_bind(nlk->ngroups, groups, sk);
1037			goto unlock;
1038		}
1039	}
1040
1041	if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1042		goto unlock;
1043	netlink_unlock_table();
1044
1045	netlink_table_grab();
1046	netlink_update_subscriptions(sk, nlk->subscriptions +
1047					 hweight32(groups) -
1048					 hweight32(nlk->groups[0]));
1049	nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1050	netlink_update_listeners(sk);
1051	netlink_table_ungrab();
1052
1053	return 0;
1054
1055unlock:
1056	netlink_unlock_table();
1057	return err;
1058}
1059
1060static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1061			   int alen, int flags)
1062{
1063	int err = 0;
1064	struct sock *sk = sock->sk;
1065	struct netlink_sock *nlk = nlk_sk(sk);
1066	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1067
1068	if (alen < sizeof(addr->sa_family))
1069		return -EINVAL;
1070
1071	if (addr->sa_family == AF_UNSPEC) {
1072		sk->sk_state	= NETLINK_UNCONNECTED;
1073		nlk->dst_portid	= 0;
1074		nlk->dst_group  = 0;
1075		return 0;
1076	}
1077	if (addr->sa_family != AF_NETLINK)
1078		return -EINVAL;
1079
1080	if (alen < sizeof(struct sockaddr_nl))
1081		return -EINVAL;
1082
1083	if ((nladdr->nl_groups || nladdr->nl_pid) &&
1084	    !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1085		return -EPERM;
1086
1087	/* No need for barriers here as we return to user-space without
1088	 * using any of the bound attributes.
1089	 */
1090	if (!nlk->bound)
1091		err = netlink_autobind(sock);
1092
1093	if (err == 0) {
1094		sk->sk_state	= NETLINK_CONNECTED;
1095		nlk->dst_portid = nladdr->nl_pid;
1096		nlk->dst_group  = ffs(nladdr->nl_groups);
1097	}
1098
1099	return err;
1100}
1101
1102static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1103			   int peer)
1104{
1105	struct sock *sk = sock->sk;
1106	struct netlink_sock *nlk = nlk_sk(sk);
1107	DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1108
1109	nladdr->nl_family = AF_NETLINK;
1110	nladdr->nl_pad = 0;
1111
1112	if (peer) {
1113		nladdr->nl_pid = nlk->dst_portid;
1114		nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1115	} else {
1116		nladdr->nl_pid = nlk->portid;
1117		netlink_lock_table();
1118		nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1119		netlink_unlock_table();
1120	}
1121	return sizeof(*nladdr);
1122}
1123
1124static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1125			 unsigned long arg)
1126{
1127	/* try to hand this ioctl down to the NIC drivers.
1128	 */
1129	return -ENOIOCTLCMD;
1130}
1131
1132static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1133{
1134	struct sock *sock;
1135	struct netlink_sock *nlk;
1136
1137	sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1138	if (!sock)
1139		return ERR_PTR(-ECONNREFUSED);
1140
1141	/* Don't bother queuing skb if kernel socket has no input function */
1142	nlk = nlk_sk(sock);
1143	if (sock->sk_state == NETLINK_CONNECTED &&
1144	    nlk->dst_portid != nlk_sk(ssk)->portid) {
1145		sock_put(sock);
1146		return ERR_PTR(-ECONNREFUSED);
1147	}
1148	return sock;
1149}
1150
1151struct sock *netlink_getsockbyfilp(struct file *filp)
1152{
1153	struct inode *inode = file_inode(filp);
1154	struct sock *sock;
1155
1156	if (!S_ISSOCK(inode->i_mode))
1157		return ERR_PTR(-ENOTSOCK);
1158
1159	sock = SOCKET_I(inode)->sk;
1160	if (sock->sk_family != AF_NETLINK)
1161		return ERR_PTR(-EINVAL);
1162
1163	sock_hold(sock);
1164	return sock;
1165}
1166
1167static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1168					       int broadcast)
1169{
1170	struct sk_buff *skb;
1171	void *data;
1172
1173	if (size <= NLMSG_GOODSIZE || broadcast)
1174		return alloc_skb(size, GFP_KERNEL);
1175
1176	size = SKB_DATA_ALIGN(size) +
1177	       SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1178
1179	data = vmalloc(size);
1180	if (data == NULL)
1181		return NULL;
1182
1183	skb = __build_skb(data, size);
1184	if (skb == NULL)
1185		vfree(data);
1186	else
1187		skb->destructor = netlink_skb_destructor;
1188
1189	return skb;
1190}
1191
1192/*
1193 * Attach a skb to a netlink socket.
1194 * The caller must hold a reference to the destination socket. On error, the
1195 * reference is dropped. The skb is not send to the destination, just all
1196 * all error checks are performed and memory in the queue is reserved.
1197 * Return values:
1198 * < 0: error. skb freed, reference to sock dropped.
1199 * 0: continue
1200 * 1: repeat lookup - reference dropped while waiting for socket memory.
1201 */
1202int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1203		      long *timeo, struct sock *ssk)
1204{
1205	struct netlink_sock *nlk;
1206
1207	nlk = nlk_sk(sk);
1208
1209	if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1210	     test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1211		DECLARE_WAITQUEUE(wait, current);
1212		if (!*timeo) {
1213			if (!ssk || netlink_is_kernel(ssk))
1214				netlink_overrun(sk);
1215			sock_put(sk);
1216			kfree_skb(skb);
1217			return -EAGAIN;
1218		}
1219
1220		__set_current_state(TASK_INTERRUPTIBLE);
1221		add_wait_queue(&nlk->wait, &wait);
1222
1223		if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1224		     test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1225		    !sock_flag(sk, SOCK_DEAD))
1226			*timeo = schedule_timeout(*timeo);
1227
1228		__set_current_state(TASK_RUNNING);
1229		remove_wait_queue(&nlk->wait, &wait);
1230		sock_put(sk);
1231
1232		if (signal_pending(current)) {
1233			kfree_skb(skb);
1234			return sock_intr_errno(*timeo);
1235		}
1236		return 1;
1237	}
1238	netlink_skb_set_owner_r(skb, sk);
1239	return 0;
1240}
1241
1242static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1243{
1244	int len = skb->len;
1245
1246	netlink_deliver_tap(sock_net(sk), skb);
1247
1248	skb_queue_tail(&sk->sk_receive_queue, skb);
1249	sk->sk_data_ready(sk);
1250	return len;
1251}
1252
1253int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1254{
1255	int len = __netlink_sendskb(sk, skb);
1256
1257	sock_put(sk);
1258	return len;
1259}
1260
1261void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1262{
1263	kfree_skb(skb);
1264	sock_put(sk);
1265}
1266
1267static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1268{
1269	int delta;
1270
1271	WARN_ON(skb->sk != NULL);
1272	delta = skb->end - skb->tail;
1273	if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1274		return skb;
1275
1276	if (skb_shared(skb)) {
1277		struct sk_buff *nskb = skb_clone(skb, allocation);
1278		if (!nskb)
1279			return skb;
1280		consume_skb(skb);
1281		skb = nskb;
1282	}
1283
1284	pskb_expand_head(skb, 0, -delta,
1285			 (allocation & ~__GFP_DIRECT_RECLAIM) |
1286			 __GFP_NOWARN | __GFP_NORETRY);
1287	return skb;
1288}
1289
1290static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1291				  struct sock *ssk)
1292{
1293	int ret;
1294	struct netlink_sock *nlk = nlk_sk(sk);
1295
1296	ret = -ECONNREFUSED;
1297	if (nlk->netlink_rcv != NULL) {
1298		ret = skb->len;
1299		netlink_skb_set_owner_r(skb, sk);
1300		NETLINK_CB(skb).sk = ssk;
1301		netlink_deliver_tap_kernel(sk, ssk, skb);
1302		nlk->netlink_rcv(skb);
1303		consume_skb(skb);
1304	} else {
1305		kfree_skb(skb);
1306	}
1307	sock_put(sk);
1308	return ret;
1309}
1310
1311int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1312		    u32 portid, int nonblock)
1313{
1314	struct sock *sk;
1315	int err;
1316	long timeo;
1317
1318	skb = netlink_trim(skb, gfp_any());
1319
1320	timeo = sock_sndtimeo(ssk, nonblock);
1321retry:
1322	sk = netlink_getsockbyportid(ssk, portid);
1323	if (IS_ERR(sk)) {
1324		kfree_skb(skb);
1325		return PTR_ERR(sk);
1326	}
1327	if (netlink_is_kernel(sk))
1328		return netlink_unicast_kernel(sk, skb, ssk);
1329
1330	if (sk_filter(sk, skb)) {
1331		err = skb->len;
1332		kfree_skb(skb);
1333		sock_put(sk);
1334		return err;
1335	}
1336
1337	err = netlink_attachskb(sk, skb, &timeo, ssk);
1338	if (err == 1)
1339		goto retry;
1340	if (err)
1341		return err;
1342
1343	return netlink_sendskb(sk, skb);
1344}
1345EXPORT_SYMBOL(netlink_unicast);
1346
1347int netlink_has_listeners(struct sock *sk, unsigned int group)
1348{
1349	int res = 0;
1350	struct listeners *listeners;
1351
1352	BUG_ON(!netlink_is_kernel(sk));
1353
1354	rcu_read_lock();
1355	listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1356
1357	if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1358		res = test_bit(group - 1, listeners->masks);
1359
1360	rcu_read_unlock();
1361
1362	return res;
1363}
1364EXPORT_SYMBOL_GPL(netlink_has_listeners);
1365
1366bool netlink_strict_get_check(struct sk_buff *skb)
1367{
1368	const struct netlink_sock *nlk = nlk_sk(NETLINK_CB(skb).sk);
1369
1370	return nlk->flags & NETLINK_F_STRICT_CHK;
1371}
1372EXPORT_SYMBOL_GPL(netlink_strict_get_check);
1373
1374static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1375{
1376	struct netlink_sock *nlk = nlk_sk(sk);
1377
1378	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1379	    !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1380		netlink_skb_set_owner_r(skb, sk);
1381		__netlink_sendskb(sk, skb);
1382		return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1383	}
1384	return -1;
1385}
1386
1387struct netlink_broadcast_data {
1388	struct sock *exclude_sk;
1389	struct net *net;
1390	u32 portid;
1391	u32 group;
1392	int failure;
1393	int delivery_failure;
1394	int congested;
1395	int delivered;
1396	gfp_t allocation;
1397	struct sk_buff *skb, *skb2;
1398	int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1399	void *tx_data;
1400};
1401
1402static void do_one_broadcast(struct sock *sk,
1403				    struct netlink_broadcast_data *p)
1404{
1405	struct netlink_sock *nlk = nlk_sk(sk);
1406	int val;
1407
1408	if (p->exclude_sk == sk)
1409		return;
1410
1411	if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1412	    !test_bit(p->group - 1, nlk->groups))
1413		return;
1414
1415	if (!net_eq(sock_net(sk), p->net)) {
1416		if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1417			return;
1418
1419		if (!peernet_has_id(sock_net(sk), p->net))
1420			return;
1421
1422		if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1423				     CAP_NET_BROADCAST))
1424			return;
1425	}
1426
1427	if (p->failure) {
1428		netlink_overrun(sk);
1429		return;
1430	}
1431
1432	sock_hold(sk);
1433	if (p->skb2 == NULL) {
1434		if (skb_shared(p->skb)) {
1435			p->skb2 = skb_clone(p->skb, p->allocation);
1436		} else {
1437			p->skb2 = skb_get(p->skb);
1438			/*
1439			 * skb ownership may have been set when
1440			 * delivered to a previous socket.
1441			 */
1442			skb_orphan(p->skb2);
1443		}
1444	}
1445	if (p->skb2 == NULL) {
1446		netlink_overrun(sk);
1447		/* Clone failed. Notify ALL listeners. */
1448		p->failure = 1;
1449		if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1450			p->delivery_failure = 1;
1451		goto out;
1452	}
1453	if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1454		kfree_skb(p->skb2);
1455		p->skb2 = NULL;
1456		goto out;
1457	}
1458	if (sk_filter(sk, p->skb2)) {
1459		kfree_skb(p->skb2);
1460		p->skb2 = NULL;
1461		goto out;
1462	}
1463	NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1464	if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1465		NETLINK_CB(p->skb2).nsid_is_set = true;
1466	val = netlink_broadcast_deliver(sk, p->skb2);
1467	if (val < 0) {
1468		netlink_overrun(sk);
1469		if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1470			p->delivery_failure = 1;
1471	} else {
1472		p->congested |= val;
1473		p->delivered = 1;
1474		p->skb2 = NULL;
1475	}
1476out:
1477	sock_put(sk);
1478}
1479
1480int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1481	u32 group, gfp_t allocation,
1482	int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1483	void *filter_data)
1484{
1485	struct net *net = sock_net(ssk);
1486	struct netlink_broadcast_data info;
1487	struct sock *sk;
1488
1489	skb = netlink_trim(skb, allocation);
1490
1491	info.exclude_sk = ssk;
1492	info.net = net;
1493	info.portid = portid;
1494	info.group = group;
1495	info.failure = 0;
1496	info.delivery_failure = 0;
1497	info.congested = 0;
1498	info.delivered = 0;
1499	info.allocation = allocation;
1500	info.skb = skb;
1501	info.skb2 = NULL;
1502	info.tx_filter = filter;
1503	info.tx_data = filter_data;
1504
1505	/* While we sleep in clone, do not allow to change socket list */
1506
1507	netlink_lock_table();
1508
1509	sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1510		do_one_broadcast(sk, &info);
1511
1512	consume_skb(skb);
1513
1514	netlink_unlock_table();
1515
1516	if (info.delivery_failure) {
1517		kfree_skb(info.skb2);
1518		return -ENOBUFS;
1519	}
1520	consume_skb(info.skb2);
1521
1522	if (info.delivered) {
1523		if (info.congested && gfpflags_allow_blocking(allocation))
1524			yield();
1525		return 0;
1526	}
1527	return -ESRCH;
1528}
1529EXPORT_SYMBOL(netlink_broadcast_filtered);
1530
1531int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1532		      u32 group, gfp_t allocation)
1533{
1534	return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1535		NULL, NULL);
1536}
1537EXPORT_SYMBOL(netlink_broadcast);
1538
1539struct netlink_set_err_data {
1540	struct sock *exclude_sk;
1541	u32 portid;
1542	u32 group;
1543	int code;
1544};
1545
1546static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1547{
1548	struct netlink_sock *nlk = nlk_sk(sk);
1549	int ret = 0;
1550
1551	if (sk == p->exclude_sk)
1552		goto out;
1553
1554	if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1555		goto out;
1556
1557	if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1558	    !test_bit(p->group - 1, nlk->groups))
1559		goto out;
1560
1561	if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1562		ret = 1;
1563		goto out;
1564	}
1565
1566	sk->sk_err = p->code;
1567	sk->sk_error_report(sk);
1568out:
1569	return ret;
1570}
1571
1572/**
1573 * netlink_set_err - report error to broadcast listeners
1574 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1575 * @portid: the PORTID of a process that we want to skip (if any)
1576 * @group: the broadcast group that will notice the error
1577 * @code: error code, must be negative (as usual in kernelspace)
1578 *
1579 * This function returns the number of broadcast listeners that have set the
1580 * NETLINK_NO_ENOBUFS socket option.
1581 */
1582int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1583{
1584	struct netlink_set_err_data info;
1585	struct sock *sk;
1586	int ret = 0;
1587
1588	info.exclude_sk = ssk;
1589	info.portid = portid;
1590	info.group = group;
1591	/* sk->sk_err wants a positive error value */
1592	info.code = -code;
1593
1594	read_lock(&nl_table_lock);
1595
1596	sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1597		ret += do_one_set_err(sk, &info);
1598
1599	read_unlock(&nl_table_lock);
1600	return ret;
1601}
1602EXPORT_SYMBOL(netlink_set_err);
1603
1604/* must be called with netlink table grabbed */
1605static void netlink_update_socket_mc(struct netlink_sock *nlk,
1606				     unsigned int group,
1607				     int is_new)
1608{
1609	int old, new = !!is_new, subscriptions;
1610
1611	old = test_bit(group - 1, nlk->groups);
1612	subscriptions = nlk->subscriptions - old + new;
1613	if (new)
1614		__set_bit(group - 1, nlk->groups);
1615	else
1616		__clear_bit(group - 1, nlk->groups);
1617	netlink_update_subscriptions(&nlk->sk, subscriptions);
1618	netlink_update_listeners(&nlk->sk);
1619}
1620
1621static int netlink_setsockopt(struct socket *sock, int level, int optname,
1622			      char __user *optval, unsigned int optlen)
1623{
1624	struct sock *sk = sock->sk;
1625	struct netlink_sock *nlk = nlk_sk(sk);
1626	unsigned int val = 0;
1627	int err;
1628
1629	if (level != SOL_NETLINK)
1630		return -ENOPROTOOPT;
1631
1632	if (optlen >= sizeof(int) &&
1633	    get_user(val, (unsigned int __user *)optval))
1634		return -EFAULT;
1635
1636	switch (optname) {
1637	case NETLINK_PKTINFO:
1638		if (val)
1639			nlk->flags |= NETLINK_F_RECV_PKTINFO;
1640		else
1641			nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1642		err = 0;
1643		break;
1644	case NETLINK_ADD_MEMBERSHIP:
1645	case NETLINK_DROP_MEMBERSHIP: {
1646		if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1647			return -EPERM;
1648		err = netlink_realloc_groups(sk);
1649		if (err)
1650			return err;
1651		if (!val || val - 1 >= nlk->ngroups)
1652			return -EINVAL;
1653		if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1654			err = nlk->netlink_bind(sock_net(sk), val);
1655			if (err)
1656				return err;
1657		}
1658		netlink_table_grab();
1659		netlink_update_socket_mc(nlk, val,
1660					 optname == NETLINK_ADD_MEMBERSHIP);
1661		netlink_table_ungrab();
1662		if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1663			nlk->netlink_unbind(sock_net(sk), val);
1664
1665		err = 0;
1666		break;
1667	}
1668	case NETLINK_BROADCAST_ERROR:
1669		if (val)
1670			nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1671		else
1672			nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1673		err = 0;
1674		break;
1675	case NETLINK_NO_ENOBUFS:
1676		if (val) {
1677			nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1678			clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1679			wake_up_interruptible(&nlk->wait);
1680		} else {
1681			nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1682		}
1683		err = 0;
1684		break;
1685	case NETLINK_LISTEN_ALL_NSID:
1686		if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1687			return -EPERM;
1688
1689		if (val)
1690			nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1691		else
1692			nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1693		err = 0;
1694		break;
1695	case NETLINK_CAP_ACK:
1696		if (val)
1697			nlk->flags |= NETLINK_F_CAP_ACK;
1698		else
1699			nlk->flags &= ~NETLINK_F_CAP_ACK;
1700		err = 0;
1701		break;
1702	case NETLINK_EXT_ACK:
1703		if (val)
1704			nlk->flags |= NETLINK_F_EXT_ACK;
1705		else
1706			nlk->flags &= ~NETLINK_F_EXT_ACK;
1707		err = 0;
1708		break;
1709	case NETLINK_GET_STRICT_CHK:
1710		if (val)
1711			nlk->flags |= NETLINK_F_STRICT_CHK;
1712		else
1713			nlk->flags &= ~NETLINK_F_STRICT_CHK;
1714		err = 0;
1715		break;
1716	default:
1717		err = -ENOPROTOOPT;
1718	}
1719	return err;
1720}
1721
1722static int netlink_getsockopt(struct socket *sock, int level, int optname,
1723			      char __user *optval, int __user *optlen)
1724{
1725	struct sock *sk = sock->sk;
1726	struct netlink_sock *nlk = nlk_sk(sk);
1727	int len, val, err;
1728
1729	if (level != SOL_NETLINK)
1730		return -ENOPROTOOPT;
1731
1732	if (get_user(len, optlen))
1733		return -EFAULT;
1734	if (len < 0)
1735		return -EINVAL;
1736
1737	switch (optname) {
1738	case NETLINK_PKTINFO:
1739		if (len < sizeof(int))
1740			return -EINVAL;
1741		len = sizeof(int);
1742		val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1743		if (put_user(len, optlen) ||
1744		    put_user(val, optval))
1745			return -EFAULT;
1746		err = 0;
1747		break;
1748	case NETLINK_BROADCAST_ERROR:
1749		if (len < sizeof(int))
1750			return -EINVAL;
1751		len = sizeof(int);
1752		val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1753		if (put_user(len, optlen) ||
1754		    put_user(val, optval))
1755			return -EFAULT;
1756		err = 0;
1757		break;
1758	case NETLINK_NO_ENOBUFS:
1759		if (len < sizeof(int))
1760			return -EINVAL;
1761		len = sizeof(int);
1762		val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1763		if (put_user(len, optlen) ||
1764		    put_user(val, optval))
1765			return -EFAULT;
1766		err = 0;
1767		break;
1768	case NETLINK_LIST_MEMBERSHIPS: {
1769		int pos, idx, shift;
1770
1771		err = 0;
1772		netlink_lock_table();
1773		for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1774			if (len - pos < sizeof(u32))
1775				break;
1776
1777			idx = pos / sizeof(unsigned long);
1778			shift = (pos % sizeof(unsigned long)) * 8;
1779			if (put_user((u32)(nlk->groups[idx] >> shift),
1780				     (u32 __user *)(optval + pos))) {
1781				err = -EFAULT;
1782				break;
1783			}
1784		}
1785		if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1786			err = -EFAULT;
1787		netlink_unlock_table();
1788		break;
1789	}
1790	case NETLINK_CAP_ACK:
1791		if (len < sizeof(int))
1792			return -EINVAL;
1793		len = sizeof(int);
1794		val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1795		if (put_user(len, optlen) ||
1796		    put_user(val, optval))
1797			return -EFAULT;
1798		err = 0;
1799		break;
1800	case NETLINK_EXT_ACK:
1801		if (len < sizeof(int))
1802			return -EINVAL;
1803		len = sizeof(int);
1804		val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1805		if (put_user(len, optlen) || put_user(val, optval))
1806			return -EFAULT;
1807		err = 0;
1808		break;
1809	case NETLINK_GET_STRICT_CHK:
1810		if (len < sizeof(int))
1811			return -EINVAL;
1812		len = sizeof(int);
1813		val = nlk->flags & NETLINK_F_STRICT_CHK ? 1 : 0;
1814		if (put_user(len, optlen) || put_user(val, optval))
1815			return -EFAULT;
1816		err = 0;
1817		break;
1818	default:
1819		err = -ENOPROTOOPT;
1820	}
1821	return err;
1822}
1823
1824static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1825{
1826	struct nl_pktinfo info;
1827
1828	info.group = NETLINK_CB(skb).dst_group;
1829	put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1830}
1831
1832static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1833					 struct sk_buff *skb)
1834{
1835	if (!NETLINK_CB(skb).nsid_is_set)
1836		return;
1837
1838	put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1839		 &NETLINK_CB(skb).nsid);
1840}
1841
1842static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1843{
1844	struct sock *sk = sock->sk;
1845	struct netlink_sock *nlk = nlk_sk(sk);
1846	DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1847	u32 dst_portid;
1848	u32 dst_group;
1849	struct sk_buff *skb;
1850	int err;
1851	struct scm_cookie scm;
1852	u32 netlink_skb_flags = 0;
1853
1854	if (msg->msg_flags&MSG_OOB)
1855		return -EOPNOTSUPP;
1856
1857	err = scm_send(sock, msg, &scm, true);
1858	if (err < 0)
1859		return err;
1860
1861	if (msg->msg_namelen) {
1862		err = -EINVAL;
1863		if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1864			goto out;
1865		if (addr->nl_family != AF_NETLINK)
1866			goto out;
1867		dst_portid = addr->nl_pid;
1868		dst_group = ffs(addr->nl_groups);
1869		err =  -EPERM;
1870		if ((dst_group || dst_portid) &&
1871		    !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1872			goto out;
1873		netlink_skb_flags |= NETLINK_SKB_DST;
1874	} else {
1875		dst_portid = nlk->dst_portid;
1876		dst_group = nlk->dst_group;
1877	}
1878
1879	if (!nlk->bound) {
1880		err = netlink_autobind(sock);
1881		if (err)
1882			goto out;
1883	} else {
1884		/* Ensure nlk is hashed and visible. */
1885		smp_rmb();
1886	}
1887
1888	err = -EMSGSIZE;
1889	if (len > sk->sk_sndbuf - 32)
1890		goto out;
1891	err = -ENOBUFS;
1892	skb = netlink_alloc_large_skb(len, dst_group);
1893	if (skb == NULL)
1894		goto out;
1895
1896	NETLINK_CB(skb).portid	= nlk->portid;
1897	NETLINK_CB(skb).dst_group = dst_group;
1898	NETLINK_CB(skb).creds	= scm.creds;
1899	NETLINK_CB(skb).flags	= netlink_skb_flags;
1900
1901	err = -EFAULT;
1902	if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1903		kfree_skb(skb);
1904		goto out;
1905	}
1906
1907	err = security_netlink_send(sk, skb);
1908	if (err) {
1909		kfree_skb(skb);
1910		goto out;
1911	}
1912
1913	if (dst_group) {
1914		refcount_inc(&skb->users);
1915		netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1916	}
1917	err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1918
1919out:
1920	scm_destroy(&scm);
1921	return err;
1922}
1923
1924static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1925			   int flags)
1926{
1927	struct scm_cookie scm;
1928	struct sock *sk = sock->sk;
1929	struct netlink_sock *nlk = nlk_sk(sk);
1930	int noblock = flags&MSG_DONTWAIT;
1931	size_t copied;
1932	struct sk_buff *skb, *data_skb;
1933	int err, ret;
1934
1935	if (flags&MSG_OOB)
1936		return -EOPNOTSUPP;
1937
1938	copied = 0;
1939
1940	skb = skb_recv_datagram(sk, flags, noblock, &err);
1941	if (skb == NULL)
1942		goto out;
1943
1944	data_skb = skb;
1945
1946#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1947	if (unlikely(skb_shinfo(skb)->frag_list)) {
1948		/*
1949		 * If this skb has a frag_list, then here that means that we
1950		 * will have to use the frag_list skb's data for compat tasks
1951		 * and the regular skb's data for normal (non-compat) tasks.
1952		 *
1953		 * If we need to send the compat skb, assign it to the
1954		 * 'data_skb' variable so that it will be used below for data
1955		 * copying. We keep 'skb' for everything else, including
1956		 * freeing both later.
1957		 */
1958		if (flags & MSG_CMSG_COMPAT)
1959			data_skb = skb_shinfo(skb)->frag_list;
1960	}
1961#endif
1962
1963	/* Record the max length of recvmsg() calls for future allocations */
1964	nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1965	nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1966				     SKB_WITH_OVERHEAD(32768));
1967
1968	copied = data_skb->len;
1969	if (len < copied) {
1970		msg->msg_flags |= MSG_TRUNC;
1971		copied = len;
1972	}
1973
1974	skb_reset_transport_header(data_skb);
1975	err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1976
1977	if (msg->msg_name) {
1978		DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1979		addr->nl_family = AF_NETLINK;
1980		addr->nl_pad    = 0;
1981		addr->nl_pid	= NETLINK_CB(skb).portid;
1982		addr->nl_groups	= netlink_group_mask(NETLINK_CB(skb).dst_group);
1983		msg->msg_namelen = sizeof(*addr);
1984	}
1985
1986	if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1987		netlink_cmsg_recv_pktinfo(msg, skb);
1988	if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1989		netlink_cmsg_listen_all_nsid(sk, msg, skb);
1990
1991	memset(&scm, 0, sizeof(scm));
1992	scm.creds = *NETLINK_CREDS(skb);
1993	if (flags & MSG_TRUNC)
1994		copied = data_skb->len;
1995
1996	skb_free_datagram(sk, skb);
1997
1998	if (nlk->cb_running &&
1999	    atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2000		ret = netlink_dump(sk);
2001		if (ret) {
2002			sk->sk_err = -ret;
2003			sk->sk_error_report(sk);
2004		}
2005	}
2006
2007	scm_recv(sock, msg, &scm, flags);
2008out:
2009	netlink_rcv_wake(sk);
2010	return err ? : copied;
2011}
2012
2013static void netlink_data_ready(struct sock *sk)
2014{
2015	BUG();
2016}
2017
2018/*
2019 *	We export these functions to other modules. They provide a
2020 *	complete set of kernel non-blocking support for message
2021 *	queueing.
2022 */
2023
2024struct sock *
2025__netlink_kernel_create(struct net *net, int unit, struct module *module,
2026			struct netlink_kernel_cfg *cfg)
2027{
2028	struct socket *sock;
2029	struct sock *sk;
2030	struct netlink_sock *nlk;
2031	struct listeners *listeners = NULL;
2032	struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2033	unsigned int groups;
2034
2035	BUG_ON(!nl_table);
2036
2037	if (unit < 0 || unit >= MAX_LINKS)
2038		return NULL;
2039
2040	if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2041		return NULL;
2042
2043	if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2044		goto out_sock_release_nosk;
2045
2046	sk = sock->sk;
2047
2048	if (!cfg || cfg->groups < 32)
2049		groups = 32;
2050	else
2051		groups = cfg->groups;
2052
2053	listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2054	if (!listeners)
2055		goto out_sock_release;
2056
2057	sk->sk_data_ready = netlink_data_ready;
2058	if (cfg && cfg->input)
2059		nlk_sk(sk)->netlink_rcv = cfg->input;
2060
2061	if (netlink_insert(sk, 0))
2062		goto out_sock_release;
2063
2064	nlk = nlk_sk(sk);
2065	nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2066
2067	netlink_table_grab();
2068	if (!nl_table[unit].registered) {
2069		nl_table[unit].groups = groups;
2070		rcu_assign_pointer(nl_table[unit].listeners, listeners);
2071		nl_table[unit].cb_mutex = cb_mutex;
2072		nl_table[unit].module = module;
2073		if (cfg) {
2074			nl_table[unit].bind = cfg->bind;
2075			nl_table[unit].unbind = cfg->unbind;
2076			nl_table[unit].flags = cfg->flags;
2077			if (cfg->compare)
2078				nl_table[unit].compare = cfg->compare;
2079		}
2080		nl_table[unit].registered = 1;
2081	} else {
2082		kfree(listeners);
2083		nl_table[unit].registered++;
2084	}
2085	netlink_table_ungrab();
2086	return sk;
2087
2088out_sock_release:
2089	kfree(listeners);
2090	netlink_kernel_release(sk);
2091	return NULL;
2092
2093out_sock_release_nosk:
2094	sock_release(sock);
2095	return NULL;
2096}
2097EXPORT_SYMBOL(__netlink_kernel_create);
2098
2099void
2100netlink_kernel_release(struct sock *sk)
2101{
2102	if (sk == NULL || sk->sk_socket == NULL)
2103		return;
2104
2105	sock_release(sk->sk_socket);
2106}
2107EXPORT_SYMBOL(netlink_kernel_release);
2108
2109int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2110{
2111	struct listeners *new, *old;
2112	struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2113
2114	if (groups < 32)
2115		groups = 32;
2116
2117	if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2118		new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2119		if (!new)
2120			return -ENOMEM;
2121		old = nl_deref_protected(tbl->listeners);
2122		memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2123		rcu_assign_pointer(tbl->listeners, new);
2124
2125		kfree_rcu(old, rcu);
2126	}
2127	tbl->groups = groups;
2128
2129	return 0;
2130}
2131
2132/**
2133 * netlink_change_ngroups - change number of multicast groups
2134 *
2135 * This changes the number of multicast groups that are available
2136 * on a certain netlink family. Note that it is not possible to
2137 * change the number of groups to below 32. Also note that it does
2138 * not implicitly call netlink_clear_multicast_users() when the
2139 * number of groups is reduced.
2140 *
2141 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2142 * @groups: The new number of groups.
2143 */
2144int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2145{
2146	int err;
2147
2148	netlink_table_grab();
2149	err = __netlink_change_ngroups(sk, groups);
2150	netlink_table_ungrab();
2151
2152	return err;
2153}
2154
2155void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2156{
2157	struct sock *sk;
2158	struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2159
2160	sk_for_each_bound(sk, &tbl->mc_list)
2161		netlink_update_socket_mc(nlk_sk(sk), group, 0);
2162}
2163
2164struct nlmsghdr *
2165__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2166{
2167	struct nlmsghdr *nlh;
2168	int size = nlmsg_msg_size(len);
2169
2170	nlh = skb_put(skb, NLMSG_ALIGN(size));
2171	nlh->nlmsg_type = type;
2172	nlh->nlmsg_len = size;
2173	nlh->nlmsg_flags = flags;
2174	nlh->nlmsg_pid = portid;
2175	nlh->nlmsg_seq = seq;
2176	if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2177		memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2178	return nlh;
2179}
2180EXPORT_SYMBOL(__nlmsg_put);
2181
2182/*
2183 * It looks a bit ugly.
2184 * It would be better to create kernel thread.
2185 */
2186
2187static int netlink_dump(struct sock *sk)
2188{
2189	struct netlink_sock *nlk = nlk_sk(sk);
2190	struct netlink_ext_ack extack = {};
2191	struct netlink_callback *cb;
2192	struct sk_buff *skb = NULL;
2193	struct nlmsghdr *nlh;
2194	struct module *module;
2195	int err = -ENOBUFS;
2196	int alloc_min_size;
2197	int alloc_size;
2198
2199	mutex_lock(nlk->cb_mutex);
2200	if (!nlk->cb_running) {
2201		err = -EINVAL;
2202		goto errout_skb;
2203	}
2204
2205	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2206		goto errout_skb;
2207
2208	/* NLMSG_GOODSIZE is small to avoid high order allocations being
2209	 * required, but it makes sense to _attempt_ a 16K bytes allocation
2210	 * to reduce number of system calls on dump operations, if user
2211	 * ever provided a big enough buffer.
2212	 */
2213	cb = &nlk->cb;
2214	alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2215
2216	if (alloc_min_size < nlk->max_recvmsg_len) {
2217		alloc_size = nlk->max_recvmsg_len;
2218		skb = alloc_skb(alloc_size,
2219				(GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2220				__GFP_NOWARN | __GFP_NORETRY);
2221	}
2222	if (!skb) {
2223		alloc_size = alloc_min_size;
2224		skb = alloc_skb(alloc_size, GFP_KERNEL);
2225	}
2226	if (!skb)
2227		goto errout_skb;
2228
2229	/* Trim skb to allocated size. User is expected to provide buffer as
2230	 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2231	 * netlink_recvmsg())). dump will pack as many smaller messages as
2232	 * could fit within the allocated skb. skb is typically allocated
2233	 * with larger space than required (could be as much as near 2x the
2234	 * requested size with align to next power of 2 approach). Allowing
2235	 * dump to use the excess space makes it difficult for a user to have a
2236	 * reasonable static buffer based on the expected largest dump of a
2237	 * single netdev. The outcome is MSG_TRUNC error.
2238	 */
2239	skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2240	netlink_skb_set_owner_r(skb, sk);
2241
2242	if (nlk->dump_done_errno > 0) {
2243		cb->extack = &extack;
2244		nlk->dump_done_errno = cb->dump(skb, cb);
2245		cb->extack = NULL;
2246	}
2247
2248	if (nlk->dump_done_errno > 0 ||
2249	    skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2250		mutex_unlock(nlk->cb_mutex);
2251
2252		if (sk_filter(sk, skb))
2253			kfree_skb(skb);
2254		else
2255			__netlink_sendskb(sk, skb);
2256		return 0;
2257	}
2258
2259	nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
2260			       sizeof(nlk->dump_done_errno),
2261			       NLM_F_MULTI | cb->answer_flags);
2262	if (WARN_ON(!nlh))
2263		goto errout_skb;
2264
2265	nl_dump_check_consistent(cb, nlh);
2266
2267	memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
2268	       sizeof(nlk->dump_done_errno));
2269
2270	if (extack._msg && nlk->flags & NETLINK_F_EXT_ACK) {
2271		nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
2272		if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack._msg))
2273			nlmsg_end(skb, nlh);
2274	}
2275
2276	if (sk_filter(sk, skb))
2277		kfree_skb(skb);
2278	else
2279		__netlink_sendskb(sk, skb);
2280
2281	if (cb->done)
2282		cb->done(cb);
2283
2284	nlk->cb_running = false;
2285	module = cb->module;
2286	skb = cb->skb;
2287	mutex_unlock(nlk->cb_mutex);
2288	module_put(module);
2289	consume_skb(skb);
2290	return 0;
2291
2292errout_skb:
2293	mutex_unlock(nlk->cb_mutex);
2294	kfree_skb(skb);
2295	return err;
2296}
2297
2298int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2299			 const struct nlmsghdr *nlh,
2300			 struct netlink_dump_control *control)
2301{
2302	struct netlink_sock *nlk, *nlk2;
2303	struct netlink_callback *cb;
2304	struct sock *sk;
 
2305	int ret;
2306
2307	refcount_inc(&skb->users);
2308
2309	sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2310	if (sk == NULL) {
2311		ret = -ECONNREFUSED;
2312		goto error_free;
2313	}
2314
2315	nlk = nlk_sk(sk);
2316	mutex_lock(nlk->cb_mutex);
2317	/* A dump is in progress... */
2318	if (nlk->cb_running) {
2319		ret = -EBUSY;
2320		goto error_unlock;
2321	}
2322	/* add reference of module which cb->dump belongs to */
2323	if (!try_module_get(control->module)) {
2324		ret = -EPROTONOSUPPORT;
2325		goto error_unlock;
2326	}
2327
2328	cb = &nlk->cb;
2329	memset(cb, 0, sizeof(*cb));
 
2330	cb->dump = control->dump;
2331	cb->done = control->done;
2332	cb->nlh = nlh;
2333	cb->data = control->data;
2334	cb->module = control->module;
2335	cb->min_dump_alloc = control->min_dump_alloc;
2336	cb->skb = skb;
2337
2338	nlk2 = nlk_sk(NETLINK_CB(skb).sk);
2339	cb->strict_check = !!(nlk2->flags & NETLINK_F_STRICT_CHK);
2340
2341	if (control->start) {
2342		ret = control->start(cb);
2343		if (ret)
2344			goto error_put;
2345	}
2346
2347	nlk->cb_running = true;
2348	nlk->dump_done_errno = INT_MAX;
2349
2350	mutex_unlock(nlk->cb_mutex);
2351
2352	ret = netlink_dump(sk);
2353
2354	sock_put(sk);
2355
2356	if (ret)
2357		return ret;
2358
2359	/* We successfully started a dump, by returning -EINTR we
2360	 * signal not to send ACK even if it was requested.
2361	 */
2362	return -EINTR;
2363
2364error_put:
2365	module_put(control->module);
2366error_unlock:
2367	sock_put(sk);
2368	mutex_unlock(nlk->cb_mutex);
2369error_free:
2370	kfree_skb(skb);
2371	return ret;
2372}
2373EXPORT_SYMBOL(__netlink_dump_start);
2374
2375void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2376		 const struct netlink_ext_ack *extack)
2377{
2378	struct sk_buff *skb;
2379	struct nlmsghdr *rep;
2380	struct nlmsgerr *errmsg;
2381	size_t payload = sizeof(*errmsg);
2382	size_t tlvlen = 0;
2383	struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2384	unsigned int flags = 0;
2385	bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK;
2386
2387	/* Error messages get the original request appened, unless the user
2388	 * requests to cap the error message, and get extra error data if
2389	 * requested.
2390	 */
2391	if (nlk_has_extack && extack && extack->_msg)
2392		tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2393
2394	if (err) {
2395		if (!(nlk->flags & NETLINK_F_CAP_ACK))
2396			payload += nlmsg_len(nlh);
2397		else
2398			flags |= NLM_F_CAPPED;
2399		if (nlk_has_extack && extack && extack->bad_attr)
2400			tlvlen += nla_total_size(sizeof(u32));
2401	} else {
2402		flags |= NLM_F_CAPPED;
2403
2404		if (nlk_has_extack && extack && extack->cookie_len)
2405			tlvlen += nla_total_size(extack->cookie_len);
2406	}
2407
2408	if (tlvlen)
2409		flags |= NLM_F_ACK_TLVS;
2410
2411	skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2412	if (!skb) {
2413		NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
2414		NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk);
2415		return;
2416	}
2417
2418	rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2419			  NLMSG_ERROR, payload, flags);
2420	errmsg = nlmsg_data(rep);
2421	errmsg->error = err;
2422	memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2423
2424	if (nlk_has_extack && extack) {
2425		if (extack->_msg) {
2426			WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2427					       extack->_msg));
2428		}
2429		if (err) {
2430			if (extack->bad_attr &&
2431			    !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2432				     (u8 *)extack->bad_attr >= in_skb->data +
2433							       in_skb->len))
2434				WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2435						    (u8 *)extack->bad_attr -
2436						    in_skb->data));
2437		} else {
2438			if (extack->cookie_len)
2439				WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2440						extack->cookie_len,
2441						extack->cookie));
2442		}
2443	}
2444
2445	nlmsg_end(skb, rep);
2446
2447	netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2448}
2449EXPORT_SYMBOL(netlink_ack);
2450
2451int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2452						   struct nlmsghdr *,
2453						   struct netlink_ext_ack *))
2454{
2455	struct netlink_ext_ack extack;
2456	struct nlmsghdr *nlh;
2457	int err;
2458
2459	while (skb->len >= nlmsg_total_size(0)) {
2460		int msglen;
2461
2462		memset(&extack, 0, sizeof(extack));
2463		nlh = nlmsg_hdr(skb);
2464		err = 0;
2465
2466		if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2467			return 0;
2468
2469		/* Only requests are handled by the kernel */
2470		if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2471			goto ack;
2472
2473		/* Skip control messages */
2474		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2475			goto ack;
2476
2477		err = cb(skb, nlh, &extack);
2478		if (err == -EINTR)
2479			goto skip;
2480
2481ack:
2482		if (nlh->nlmsg_flags & NLM_F_ACK || err)
2483			netlink_ack(skb, nlh, err, &extack);
2484
2485skip:
2486		msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2487		if (msglen > skb->len)
2488			msglen = skb->len;
2489		skb_pull(skb, msglen);
2490	}
2491
2492	return 0;
2493}
2494EXPORT_SYMBOL(netlink_rcv_skb);
2495
2496/**
2497 * nlmsg_notify - send a notification netlink message
2498 * @sk: netlink socket to use
2499 * @skb: notification message
2500 * @portid: destination netlink portid for reports or 0
2501 * @group: destination multicast group or 0
2502 * @report: 1 to report back, 0 to disable
2503 * @flags: allocation flags
2504 */
2505int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2506		 unsigned int group, int report, gfp_t flags)
2507{
2508	int err = 0;
2509
2510	if (group) {
2511		int exclude_portid = 0;
2512
2513		if (report) {
2514			refcount_inc(&skb->users);
2515			exclude_portid = portid;
2516		}
2517
2518		/* errors reported via destination sk->sk_err, but propagate
2519		 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2520		err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2521	}
2522
2523	if (report) {
2524		int err2;
2525
2526		err2 = nlmsg_unicast(sk, skb, portid);
2527		if (!err || err == -ESRCH)
2528			err = err2;
2529	}
2530
2531	return err;
2532}
2533EXPORT_SYMBOL(nlmsg_notify);
2534
2535#ifdef CONFIG_PROC_FS
2536struct nl_seq_iter {
2537	struct seq_net_private p;
2538	struct rhashtable_iter hti;
2539	int link;
2540};
2541
2542static void netlink_walk_start(struct nl_seq_iter *iter)
2543{
2544	rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti);
 
 
 
 
 
 
 
 
2545	rhashtable_walk_start(&iter->hti);
 
 
2546}
2547
2548static void netlink_walk_stop(struct nl_seq_iter *iter)
2549{
2550	rhashtable_walk_stop(&iter->hti);
2551	rhashtable_walk_exit(&iter->hti);
2552}
2553
2554static void *__netlink_seq_next(struct seq_file *seq)
2555{
2556	struct nl_seq_iter *iter = seq->private;
2557	struct netlink_sock *nlk;
2558
2559	do {
2560		for (;;) {
 
 
2561			nlk = rhashtable_walk_next(&iter->hti);
2562
2563			if (IS_ERR(nlk)) {
2564				if (PTR_ERR(nlk) == -EAGAIN)
2565					continue;
2566
2567				return nlk;
2568			}
2569
2570			if (nlk)
2571				break;
2572
2573			netlink_walk_stop(iter);
2574			if (++iter->link >= MAX_LINKS)
2575				return NULL;
2576
2577			netlink_walk_start(iter);
 
 
2578		}
2579	} while (sock_net(&nlk->sk) != seq_file_net(seq));
2580
2581	return nlk;
2582}
2583
2584static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2585{
2586	struct nl_seq_iter *iter = seq->private;
2587	void *obj = SEQ_START_TOKEN;
2588	loff_t pos;
 
2589
2590	iter->link = 0;
2591
2592	netlink_walk_start(iter);
 
 
2593
2594	for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2595		obj = __netlink_seq_next(seq);
2596
2597	return obj;
2598}
2599
2600static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2601{
2602	++*pos;
2603	return __netlink_seq_next(seq);
2604}
2605
2606static void netlink_seq_stop(struct seq_file *seq, void *v)
2607{
2608	struct nl_seq_iter *iter = seq->private;
2609
2610	if (iter->link >= MAX_LINKS)
2611		return;
2612
2613	netlink_walk_stop(iter);
2614}
2615
2616
2617static int netlink_seq_show(struct seq_file *seq, void *v)
2618{
2619	if (v == SEQ_START_TOKEN) {
2620		seq_puts(seq,
2621			 "sk               Eth Pid        Groups   "
2622			 "Rmem     Wmem     Dump  Locks    Drops    Inode\n");
2623	} else {
2624		struct sock *s = v;
2625		struct netlink_sock *nlk = nlk_sk(s);
2626
2627		seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n",
2628			   s,
2629			   s->sk_protocol,
2630			   nlk->portid,
2631			   nlk->groups ? (u32)nlk->groups[0] : 0,
2632			   sk_rmem_alloc_get(s),
2633			   sk_wmem_alloc_get(s),
2634			   nlk->cb_running,
2635			   refcount_read(&s->sk_refcnt),
2636			   atomic_read(&s->sk_drops),
2637			   sock_i_ino(s)
2638			);
2639
2640	}
2641	return 0;
2642}
2643
2644static const struct seq_operations netlink_seq_ops = {
2645	.start  = netlink_seq_start,
2646	.next   = netlink_seq_next,
2647	.stop   = netlink_seq_stop,
2648	.show   = netlink_seq_show,
2649};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2650#endif
2651
2652int netlink_register_notifier(struct notifier_block *nb)
2653{
2654	return blocking_notifier_chain_register(&netlink_chain, nb);
2655}
2656EXPORT_SYMBOL(netlink_register_notifier);
2657
2658int netlink_unregister_notifier(struct notifier_block *nb)
2659{
2660	return blocking_notifier_chain_unregister(&netlink_chain, nb);
2661}
2662EXPORT_SYMBOL(netlink_unregister_notifier);
2663
2664static const struct proto_ops netlink_ops = {
2665	.family =	PF_NETLINK,
2666	.owner =	THIS_MODULE,
2667	.release =	netlink_release,
2668	.bind =		netlink_bind,
2669	.connect =	netlink_connect,
2670	.socketpair =	sock_no_socketpair,
2671	.accept =	sock_no_accept,
2672	.getname =	netlink_getname,
2673	.poll =		datagram_poll,
2674	.ioctl =	netlink_ioctl,
2675	.listen =	sock_no_listen,
2676	.shutdown =	sock_no_shutdown,
2677	.setsockopt =	netlink_setsockopt,
2678	.getsockopt =	netlink_getsockopt,
2679	.sendmsg =	netlink_sendmsg,
2680	.recvmsg =	netlink_recvmsg,
2681	.mmap =		sock_no_mmap,
2682	.sendpage =	sock_no_sendpage,
2683};
2684
2685static const struct net_proto_family netlink_family_ops = {
2686	.family = PF_NETLINK,
2687	.create = netlink_create,
2688	.owner	= THIS_MODULE,	/* for consistency 8) */
2689};
2690
2691static int __net_init netlink_net_init(struct net *net)
2692{
2693#ifdef CONFIG_PROC_FS
2694	if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops,
2695			sizeof(struct nl_seq_iter)))
2696		return -ENOMEM;
2697#endif
2698	return 0;
2699}
2700
2701static void __net_exit netlink_net_exit(struct net *net)
2702{
2703#ifdef CONFIG_PROC_FS
2704	remove_proc_entry("netlink", net->proc_net);
2705#endif
2706}
2707
2708static void __init netlink_add_usersock_entry(void)
2709{
2710	struct listeners *listeners;
2711	int groups = 32;
2712
2713	listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2714	if (!listeners)
2715		panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2716
2717	netlink_table_grab();
2718
2719	nl_table[NETLINK_USERSOCK].groups = groups;
2720	rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2721	nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2722	nl_table[NETLINK_USERSOCK].registered = 1;
2723	nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2724
2725	netlink_table_ungrab();
2726}
2727
2728static struct pernet_operations __net_initdata netlink_net_ops = {
2729	.init = netlink_net_init,
2730	.exit = netlink_net_exit,
2731};
2732
2733static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2734{
2735	const struct netlink_sock *nlk = data;
2736	struct netlink_compare_arg arg;
2737
2738	netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2739	return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2740}
2741
2742static const struct rhashtable_params netlink_rhashtable_params = {
2743	.head_offset = offsetof(struct netlink_sock, node),
2744	.key_len = netlink_compare_arg_len,
2745	.obj_hashfn = netlink_hash,
2746	.obj_cmpfn = netlink_compare,
2747	.automatic_shrinking = true,
2748};
2749
2750static int __init netlink_proto_init(void)
2751{
2752	int i;
2753	int err = proto_register(&netlink_proto, 0);
2754
2755	if (err != 0)
2756		goto out;
2757
2758	BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2759
2760	nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2761	if (!nl_table)
2762		goto panic;
2763
2764	for (i = 0; i < MAX_LINKS; i++) {
2765		if (rhashtable_init(&nl_table[i].hash,
2766				    &netlink_rhashtable_params) < 0) {
2767			while (--i > 0)
2768				rhashtable_destroy(&nl_table[i].hash);
2769			kfree(nl_table);
2770			goto panic;
2771		}
2772	}
2773
2774	netlink_add_usersock_entry();
2775
2776	sock_register(&netlink_family_ops);
2777	register_pernet_subsys(&netlink_net_ops);
2778	register_pernet_subsys(&netlink_tap_net_ops);
2779	/* The netlink device handler may be needed early. */
2780	rtnetlink_init();
2781out:
2782	return err;
2783panic:
2784	panic("netlink_init: Cannot allocate nl_table\n");
2785}
2786
2787core_initcall(netlink_proto_init);