2 * NETLINK Kernel-user communication protocol.
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Patrick McHardy <kaber@trash.net>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
14 * added netlink_proto_exit
15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
16 * use nlk_sk, as sk->protinfo is on a diet 8)
17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
18 * - inc module use count of module that owns
19 * the kernel socket in case userspace opens
20 * socket of same protocol
21 * - remove all module support, since netlink is
22 * mandatory if CONFIG_NET=y these days
25 #include <linux/module.h>
27 #include <linux/capability.h>
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/sched.h>
32 #include <linux/errno.h>
33 #include <linux/string.h>
34 #include <linux/stat.h>
35 #include <linux/socket.h>
37 #include <linux/fcntl.h>
38 #include <linux/termios.h>
39 #include <linux/sockios.h>
40 #include <linux/net.h>
42 #include <linux/slab.h>
43 #include <linux/uaccess.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/rtnetlink.h>
47 #include <linux/proc_fs.h>
48 #include <linux/seq_file.h>
49 #include <linux/notifier.h>
50 #include <linux/security.h>
51 #include <linux/jhash.h>
52 #include <linux/jiffies.h>
53 #include <linux/random.h>
54 #include <linux/bitops.h>
56 #include <linux/types.h>
57 #include <linux/audit.h>
58 #include <linux/mutex.h>
59 #include <linux/vmalloc.h>
60 #include <linux/if_arp.h>
61 #include <linux/rhashtable.h>
62 #include <asm/cacheflush.h>
63 #include <linux/hash.h>
64 #include <linux/genetlink.h>
65 #include <linux/net_namespace.h>
66 #include <linux/nospec.h>
68 #include <net/net_namespace.h>
69 #include <net/netns/generic.h>
72 #include <net/netlink.h>
74 #include "af_netlink.h"
78 unsigned long masks[0];
82 #define NETLINK_S_CONGESTED 0x0
84 static inline int netlink_is_kernel(struct sock *sk)
86 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
89 struct netlink_table *nl_table __read_mostly;
90 EXPORT_SYMBOL_GPL(nl_table);
92 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
94 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
96 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
99 "nlk_cb_mutex-USERSOCK",
100 "nlk_cb_mutex-FIREWALL",
101 "nlk_cb_mutex-SOCK_DIAG",
102 "nlk_cb_mutex-NFLOG",
104 "nlk_cb_mutex-SELINUX",
105 "nlk_cb_mutex-ISCSI",
106 "nlk_cb_mutex-AUDIT",
107 "nlk_cb_mutex-FIB_LOOKUP",
108 "nlk_cb_mutex-CONNECTOR",
109 "nlk_cb_mutex-NETFILTER",
110 "nlk_cb_mutex-IP6_FW",
111 "nlk_cb_mutex-DNRTMSG",
112 "nlk_cb_mutex-KOBJECT_UEVENT",
113 "nlk_cb_mutex-GENERIC",
115 "nlk_cb_mutex-SCSITRANSPORT",
116 "nlk_cb_mutex-ECRYPTFS",
118 "nlk_cb_mutex-CRYPTO",
129 "nlk_cb_mutex-MAX_LINKS"
132 static int netlink_dump(struct sock *sk);
134 /* nl_table locking explained:
135 * Lookup and traversal are protected with an RCU read-side lock. Insertion
136 * and removal are protected with per bucket lock while using RCU list
137 * modification primitives and may run in parallel to RCU protected lookups.
138 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
139 * been acquired * either during or after the socket has been removed from
140 * the list and after an RCU grace period.
142 DEFINE_RWLOCK(nl_table_lock);
143 EXPORT_SYMBOL_GPL(nl_table_lock);
144 static atomic_t nl_table_users = ATOMIC_INIT(0);
146 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
148 static BLOCKING_NOTIFIER_HEAD(netlink_chain);
151 static const struct rhashtable_params netlink_rhashtable_params;
153 static inline u32 netlink_group_mask(u32 group)
155 return group ? 1 << (group - 1) : 0;
158 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
161 unsigned int len = skb_end_offset(skb);
164 new = alloc_skb(len, gfp_mask);
168 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
169 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
170 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
172 skb_put_data(new, skb->data, len);
176 static unsigned int netlink_tap_net_id;
178 struct netlink_tap_net {
179 struct list_head netlink_tap_all;
180 struct mutex netlink_tap_lock;
183 int netlink_add_tap(struct netlink_tap *nt)
185 struct net *net = dev_net(nt->dev);
186 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
188 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
191 mutex_lock(&nn->netlink_tap_lock);
192 list_add_rcu(&nt->list, &nn->netlink_tap_all);
193 mutex_unlock(&nn->netlink_tap_lock);
195 __module_get(nt->module);
199 EXPORT_SYMBOL_GPL(netlink_add_tap);
201 static int __netlink_remove_tap(struct netlink_tap *nt)
203 struct net *net = dev_net(nt->dev);
204 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
206 struct netlink_tap *tmp;
208 mutex_lock(&nn->netlink_tap_lock);
210 list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
212 list_del_rcu(&nt->list);
218 pr_warn("__netlink_remove_tap: %p not found\n", nt);
220 mutex_unlock(&nn->netlink_tap_lock);
223 module_put(nt->module);
225 return found ? 0 : -ENODEV;
228 int netlink_remove_tap(struct netlink_tap *nt)
232 ret = __netlink_remove_tap(nt);
237 EXPORT_SYMBOL_GPL(netlink_remove_tap);
239 static __net_init int netlink_tap_init_net(struct net *net)
241 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
243 INIT_LIST_HEAD(&nn->netlink_tap_all);
244 mutex_init(&nn->netlink_tap_lock);
248 static void __net_exit netlink_tap_exit_net(struct net *net)
252 static struct pernet_operations netlink_tap_net_ops = {
253 .init = netlink_tap_init_net,
254 .exit = netlink_tap_exit_net,
255 .id = &netlink_tap_net_id,
256 .size = sizeof(struct netlink_tap_net),
259 static bool netlink_filter_tap(const struct sk_buff *skb)
261 struct sock *sk = skb->sk;
263 /* We take the more conservative approach and
264 * whitelist socket protocols that may pass.
266 switch (sk->sk_protocol) {
268 case NETLINK_USERSOCK:
269 case NETLINK_SOCK_DIAG:
272 case NETLINK_FIB_LOOKUP:
273 case NETLINK_NETFILTER:
274 case NETLINK_GENERIC:
281 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
282 struct net_device *dev)
284 struct sk_buff *nskb;
285 struct sock *sk = skb->sk;
288 if (!net_eq(dev_net(dev), sock_net(sk)))
293 if (is_vmalloc_addr(skb->head))
294 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
296 nskb = skb_clone(skb, GFP_ATOMIC);
299 nskb->protocol = htons((u16) sk->sk_protocol);
300 nskb->pkt_type = netlink_is_kernel(sk) ?
301 PACKET_KERNEL : PACKET_USER;
302 skb_reset_network_header(nskb);
303 ret = dev_queue_xmit(nskb);
304 if (unlikely(ret > 0))
305 ret = net_xmit_errno(ret);
312 static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
315 struct netlink_tap *tmp;
317 if (!netlink_filter_tap(skb))
320 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
321 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
327 static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
329 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
333 if (unlikely(!list_empty(&nn->netlink_tap_all)))
334 __netlink_deliver_tap(skb, nn);
339 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
342 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
343 netlink_deliver_tap(sock_net(dst), skb);
346 static void netlink_overrun(struct sock *sk)
348 struct netlink_sock *nlk = nlk_sk(sk);
350 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
351 if (!test_and_set_bit(NETLINK_S_CONGESTED,
352 &nlk_sk(sk)->state)) {
353 sk->sk_err = ENOBUFS;
354 sk->sk_error_report(sk);
357 atomic_inc(&sk->sk_drops);
360 static void netlink_rcv_wake(struct sock *sk)
362 struct netlink_sock *nlk = nlk_sk(sk);
364 if (skb_queue_empty(&sk->sk_receive_queue))
365 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
366 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
367 wake_up_interruptible(&nlk->wait);
370 static void netlink_skb_destructor(struct sk_buff *skb)
372 if (is_vmalloc_addr(skb->head)) {
374 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
383 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
385 WARN_ON(skb->sk != NULL);
387 skb->destructor = netlink_skb_destructor;
388 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
389 sk_mem_charge(sk, skb->truesize);
392 static void netlink_sock_destruct(struct sock *sk)
394 struct netlink_sock *nlk = nlk_sk(sk);
396 if (nlk->cb_running) {
398 nlk->cb.done(&nlk->cb);
399 module_put(nlk->cb.module);
400 kfree_skb(nlk->cb.skb);
403 skb_queue_purge(&sk->sk_receive_queue);
405 if (!sock_flag(sk, SOCK_DEAD)) {
406 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
410 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
411 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
412 WARN_ON(nlk_sk(sk)->groups);
415 static void netlink_sock_destruct_work(struct work_struct *work)
417 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
423 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
424 * SMP. Look, when several writers sleep and reader wakes them up, all but one
425 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
426 * this, _but_ remember, it adds useless work on UP machines.
429 void netlink_table_grab(void)
430 __acquires(nl_table_lock)
434 write_lock_irq(&nl_table_lock);
436 if (atomic_read(&nl_table_users)) {
437 DECLARE_WAITQUEUE(wait, current);
439 add_wait_queue_exclusive(&nl_table_wait, &wait);
441 set_current_state(TASK_UNINTERRUPTIBLE);
442 if (atomic_read(&nl_table_users) == 0)
444 write_unlock_irq(&nl_table_lock);
446 write_lock_irq(&nl_table_lock);
449 __set_current_state(TASK_RUNNING);
450 remove_wait_queue(&nl_table_wait, &wait);
454 void netlink_table_ungrab(void)
455 __releases(nl_table_lock)
457 write_unlock_irq(&nl_table_lock);
458 wake_up(&nl_table_wait);
462 netlink_lock_table(void)
464 /* read_lock() synchronizes us to netlink_table_grab */
466 read_lock(&nl_table_lock);
467 atomic_inc(&nl_table_users);
468 read_unlock(&nl_table_lock);
472 netlink_unlock_table(void)
474 if (atomic_dec_and_test(&nl_table_users))
475 wake_up(&nl_table_wait);
478 struct netlink_compare_arg
484 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
485 #define netlink_compare_arg_len \
486 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
488 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
491 const struct netlink_compare_arg *x = arg->key;
492 const struct netlink_sock *nlk = ptr;
494 return nlk->portid != x->portid ||
495 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
498 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
499 struct net *net, u32 portid)
501 memset(arg, 0, sizeof(*arg));
502 write_pnet(&arg->pnet, net);
503 arg->portid = portid;
506 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
509 struct netlink_compare_arg arg;
511 netlink_compare_arg_init(&arg, net, portid);
512 return rhashtable_lookup_fast(&table->hash, &arg,
513 netlink_rhashtable_params);
516 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
518 struct netlink_compare_arg arg;
520 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
521 return rhashtable_lookup_insert_key(&table->hash, &arg,
523 netlink_rhashtable_params);
526 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
528 struct netlink_table *table = &nl_table[protocol];
532 sk = __netlink_lookup(table, portid, net);
540 static const struct proto_ops netlink_ops;
543 netlink_update_listeners(struct sock *sk)
545 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
548 struct listeners *listeners;
550 listeners = nl_deref_protected(tbl->listeners);
554 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
556 sk_for_each_bound(sk, &tbl->mc_list) {
557 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
558 mask |= nlk_sk(sk)->groups[i];
560 listeners->masks[i] = mask;
562 /* this function is only called with the netlink table "grabbed", which
563 * makes sure updates are visible before bind or setsockopt return. */
566 static int netlink_insert(struct sock *sk, u32 portid)
568 struct netlink_table *table = &nl_table[sk->sk_protocol];
573 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
574 if (nlk_sk(sk)->bound)
578 if (BITS_PER_LONG > 32 &&
579 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
582 nlk_sk(sk)->portid = portid;
585 err = __netlink_insert(table, sk);
587 /* In case the hashtable backend returns with -EBUSY
588 * from here, it must not escape to the caller.
590 if (unlikely(err == -EBUSY))
598 /* We need to ensure that the socket is hashed and visible. */
600 nlk_sk(sk)->bound = portid;
607 static void netlink_remove(struct sock *sk)
609 struct netlink_table *table;
611 table = &nl_table[sk->sk_protocol];
612 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
613 netlink_rhashtable_params)) {
614 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
618 netlink_table_grab();
619 if (nlk_sk(sk)->subscriptions) {
620 __sk_del_bind_node(sk);
621 netlink_update_listeners(sk);
623 if (sk->sk_protocol == NETLINK_GENERIC)
624 atomic_inc(&genl_sk_destructing_cnt);
625 netlink_table_ungrab();
628 static struct proto netlink_proto = {
630 .owner = THIS_MODULE,
631 .obj_size = sizeof(struct netlink_sock),
634 static int __netlink_create(struct net *net, struct socket *sock,
635 struct mutex *cb_mutex, int protocol,
639 struct netlink_sock *nlk;
641 sock->ops = &netlink_ops;
643 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
647 sock_init_data(sock, sk);
651 nlk->cb_mutex = cb_mutex;
653 nlk->cb_mutex = &nlk->cb_def_mutex;
654 mutex_init(nlk->cb_mutex);
655 lockdep_set_class_and_name(nlk->cb_mutex,
656 nlk_cb_mutex_keys + protocol,
657 nlk_cb_mutex_key_strings[protocol]);
659 init_waitqueue_head(&nlk->wait);
661 sk->sk_destruct = netlink_sock_destruct;
662 sk->sk_protocol = protocol;
666 static int netlink_create(struct net *net, struct socket *sock, int protocol,
669 struct module *module = NULL;
670 struct mutex *cb_mutex;
671 struct netlink_sock *nlk;
672 int (*bind)(struct net *net, int group);
673 void (*unbind)(struct net *net, int group);
676 sock->state = SS_UNCONNECTED;
678 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
679 return -ESOCKTNOSUPPORT;
681 if (protocol < 0 || protocol >= MAX_LINKS)
682 return -EPROTONOSUPPORT;
683 protocol = array_index_nospec(protocol, MAX_LINKS);
685 netlink_lock_table();
686 #ifdef CONFIG_MODULES
687 if (!nl_table[protocol].registered) {
688 netlink_unlock_table();
689 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
690 netlink_lock_table();
693 if (nl_table[protocol].registered &&
694 try_module_get(nl_table[protocol].module))
695 module = nl_table[protocol].module;
697 err = -EPROTONOSUPPORT;
698 cb_mutex = nl_table[protocol].cb_mutex;
699 bind = nl_table[protocol].bind;
700 unbind = nl_table[protocol].unbind;
701 netlink_unlock_table();
706 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
711 sock_prot_inuse_add(net, &netlink_proto, 1);
714 nlk = nlk_sk(sock->sk);
715 nlk->module = module;
716 nlk->netlink_bind = bind;
717 nlk->netlink_unbind = unbind;
726 static void deferred_put_nlk_sk(struct rcu_head *head)
728 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
729 struct sock *sk = &nlk->sk;
734 if (!refcount_dec_and_test(&sk->sk_refcnt))
737 if (nlk->cb_running && nlk->cb.done) {
738 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
739 schedule_work(&nlk->work);
746 static int netlink_release(struct socket *sock)
748 struct sock *sk = sock->sk;
749 struct netlink_sock *nlk;
759 * OK. Socket is unlinked, any packets that arrive now
763 /* must not acquire netlink_table_lock in any way again before unbind
764 * and notifying genetlink is done as otherwise it might deadlock
766 if (nlk->netlink_unbind) {
769 for (i = 0; i < nlk->ngroups; i++)
770 if (test_bit(i, nlk->groups))
771 nlk->netlink_unbind(sock_net(sk), i + 1);
773 if (sk->sk_protocol == NETLINK_GENERIC &&
774 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
775 wake_up(&genl_sk_destructing_waitq);
778 wake_up_interruptible_all(&nlk->wait);
780 skb_queue_purge(&sk->sk_write_queue);
782 if (nlk->portid && nlk->bound) {
783 struct netlink_notify n = {
785 .protocol = sk->sk_protocol,
786 .portid = nlk->portid,
788 blocking_notifier_call_chain(&netlink_chain,
789 NETLINK_URELEASE, &n);
792 module_put(nlk->module);
794 if (netlink_is_kernel(sk)) {
795 netlink_table_grab();
796 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
797 if (--nl_table[sk->sk_protocol].registered == 0) {
798 struct listeners *old;
800 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
801 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
803 nl_table[sk->sk_protocol].module = NULL;
804 nl_table[sk->sk_protocol].bind = NULL;
805 nl_table[sk->sk_protocol].unbind = NULL;
806 nl_table[sk->sk_protocol].flags = 0;
807 nl_table[sk->sk_protocol].registered = 0;
809 netlink_table_ungrab();
813 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
815 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
819 static int netlink_autobind(struct socket *sock)
821 struct sock *sk = sock->sk;
822 struct net *net = sock_net(sk);
823 struct netlink_table *table = &nl_table[sk->sk_protocol];
824 s32 portid = task_tgid_vnr(current);
832 ok = !__netlink_lookup(table, portid, net);
835 /* Bind collision, search negative portid values. */
837 /* rover will be in range [S32_MIN, -4097] */
838 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
839 else if (rover >= -4096)
845 err = netlink_insert(sk, portid);
846 if (err == -EADDRINUSE)
849 /* If 2 threads race to autobind, that is fine. */
857 * __netlink_ns_capable - General netlink message capability test
858 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
859 * @user_ns: The user namespace of the capability to use
860 * @cap: The capability to use
862 * Test to see if the opener of the socket we received the message
863 * from had when the netlink socket was created and the sender of the
864 * message has has the capability @cap in the user namespace @user_ns.
866 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
867 struct user_namespace *user_ns, int cap)
869 return ((nsp->flags & NETLINK_SKB_DST) ||
870 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
871 ns_capable(user_ns, cap);
873 EXPORT_SYMBOL(__netlink_ns_capable);
876 * netlink_ns_capable - General netlink message capability test
877 * @skb: socket buffer holding a netlink command from userspace
878 * @user_ns: The user namespace of the capability to use
879 * @cap: The capability to use
881 * Test to see if the opener of the socket we received the message
882 * from had when the netlink socket was created and the sender of the
883 * message has has the capability @cap in the user namespace @user_ns.
885 bool netlink_ns_capable(const struct sk_buff *skb,
886 struct user_namespace *user_ns, int cap)
888 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
890 EXPORT_SYMBOL(netlink_ns_capable);
893 * netlink_capable - Netlink global message capability test
894 * @skb: socket buffer holding a netlink command from userspace
895 * @cap: The capability to use
897 * Test to see if the opener of the socket we received the message
898 * from had when the netlink socket was created and the sender of the
899 * message has has the capability @cap in all user namespaces.
901 bool netlink_capable(const struct sk_buff *skb, int cap)
903 return netlink_ns_capable(skb, &init_user_ns, cap);
905 EXPORT_SYMBOL(netlink_capable);
908 * netlink_net_capable - Netlink network namespace message capability test
909 * @skb: socket buffer holding a netlink command from userspace
910 * @cap: The capability to use
912 * Test to see if the opener of the socket we received the message
913 * from had when the netlink socket was created and the sender of the
914 * message has has the capability @cap over the network namespace of
915 * the socket we received the message from.
917 bool netlink_net_capable(const struct sk_buff *skb, int cap)
919 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
921 EXPORT_SYMBOL(netlink_net_capable);
923 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
925 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
926 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
930 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
932 struct netlink_sock *nlk = nlk_sk(sk);
934 if (nlk->subscriptions && !subscriptions)
935 __sk_del_bind_node(sk);
936 else if (!nlk->subscriptions && subscriptions)
937 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
938 nlk->subscriptions = subscriptions;
941 static int netlink_realloc_groups(struct sock *sk)
943 struct netlink_sock *nlk = nlk_sk(sk);
945 unsigned long *new_groups;
948 netlink_table_grab();
950 groups = nl_table[sk->sk_protocol].groups;
951 if (!nl_table[sk->sk_protocol].registered) {
956 if (nlk->ngroups >= groups)
959 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
960 if (new_groups == NULL) {
964 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
965 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
967 nlk->groups = new_groups;
968 nlk->ngroups = groups;
970 netlink_table_ungrab();
974 static void netlink_undo_bind(int group, long unsigned int groups,
977 struct netlink_sock *nlk = nlk_sk(sk);
980 if (!nlk->netlink_unbind)
983 for (undo = 0; undo < group; undo++)
984 if (test_bit(undo, &groups))
985 nlk->netlink_unbind(sock_net(sk), undo + 1);
988 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
991 struct sock *sk = sock->sk;
992 struct net *net = sock_net(sk);
993 struct netlink_sock *nlk = nlk_sk(sk);
994 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
996 unsigned long groups = nladdr->nl_groups;
999 if (addr_len < sizeof(struct sockaddr_nl))
1002 if (nladdr->nl_family != AF_NETLINK)
1005 /* Only superuser is allowed to listen multicasts */
1007 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1009 err = netlink_realloc_groups(sk);
1014 if (nlk->ngroups < BITS_PER_LONG)
1015 groups &= (1UL << nlk->ngroups) - 1;
1019 /* Ensure nlk->portid is up-to-date. */
1022 if (nladdr->nl_pid != nlk->portid)
1026 netlink_lock_table();
1027 if (nlk->netlink_bind && groups) {
1030 for (group = 0; group < nlk->ngroups; group++) {
1031 if (!test_bit(group, &groups))
1033 err = nlk->netlink_bind(net, group + 1);
1036 netlink_undo_bind(group, groups, sk);
1041 /* No need for barriers here as we return to user-space without
1042 * using any of the bound attributes.
1045 err = nladdr->nl_pid ?
1046 netlink_insert(sk, nladdr->nl_pid) :
1047 netlink_autobind(sock);
1049 netlink_undo_bind(nlk->ngroups, groups, sk);
1054 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1056 netlink_unlock_table();
1058 netlink_table_grab();
1059 netlink_update_subscriptions(sk, nlk->subscriptions +
1061 hweight32(nlk->groups[0]));
1062 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1063 netlink_update_listeners(sk);
1064 netlink_table_ungrab();
1069 netlink_unlock_table();
1073 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1074 int alen, int flags)
1077 struct sock *sk = sock->sk;
1078 struct netlink_sock *nlk = nlk_sk(sk);
1079 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1081 if (alen < sizeof(addr->sa_family))
1084 if (addr->sa_family == AF_UNSPEC) {
1085 sk->sk_state = NETLINK_UNCONNECTED;
1086 nlk->dst_portid = 0;
1090 if (addr->sa_family != AF_NETLINK)
1093 if (alen < sizeof(struct sockaddr_nl))
1096 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1097 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1100 /* No need for barriers here as we return to user-space without
1101 * using any of the bound attributes.
1104 err = netlink_autobind(sock);
1107 sk->sk_state = NETLINK_CONNECTED;
1108 nlk->dst_portid = nladdr->nl_pid;
1109 nlk->dst_group = ffs(nladdr->nl_groups);
1115 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1118 struct sock *sk = sock->sk;
1119 struct netlink_sock *nlk = nlk_sk(sk);
1120 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1122 nladdr->nl_family = AF_NETLINK;
1126 nladdr->nl_pid = nlk->dst_portid;
1127 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1129 nladdr->nl_pid = nlk->portid;
1130 netlink_lock_table();
1131 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1132 netlink_unlock_table();
1134 return sizeof(*nladdr);
1137 static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1140 /* try to hand this ioctl down to the NIC drivers.
1142 return -ENOIOCTLCMD;
1145 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1148 struct netlink_sock *nlk;
1150 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1152 return ERR_PTR(-ECONNREFUSED);
1154 /* Don't bother queuing skb if kernel socket has no input function */
1156 if (sock->sk_state == NETLINK_CONNECTED &&
1157 nlk->dst_portid != nlk_sk(ssk)->portid) {
1159 return ERR_PTR(-ECONNREFUSED);
1164 struct sock *netlink_getsockbyfilp(struct file *filp)
1166 struct inode *inode = file_inode(filp);
1169 if (!S_ISSOCK(inode->i_mode))
1170 return ERR_PTR(-ENOTSOCK);
1172 sock = SOCKET_I(inode)->sk;
1173 if (sock->sk_family != AF_NETLINK)
1174 return ERR_PTR(-EINVAL);
1180 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1183 struct sk_buff *skb;
1186 if (size <= NLMSG_GOODSIZE || broadcast)
1187 return alloc_skb(size, GFP_KERNEL);
1189 size = SKB_DATA_ALIGN(size) +
1190 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1192 data = vmalloc(size);
1196 skb = __build_skb(data, size);
1200 skb->destructor = netlink_skb_destructor;
1206 * Attach a skb to a netlink socket.
1207 * The caller must hold a reference to the destination socket. On error, the
1208 * reference is dropped. The skb is not send to the destination, just all
1209 * all error checks are performed and memory in the queue is reserved.
1211 * < 0: error. skb freed, reference to sock dropped.
1213 * 1: repeat lookup - reference dropped while waiting for socket memory.
1215 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1216 long *timeo, struct sock *ssk)
1218 struct netlink_sock *nlk;
1222 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1223 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1224 DECLARE_WAITQUEUE(wait, current);
1226 if (!ssk || netlink_is_kernel(ssk))
1227 netlink_overrun(sk);
1233 __set_current_state(TASK_INTERRUPTIBLE);
1234 add_wait_queue(&nlk->wait, &wait);
1236 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1237 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1238 !sock_flag(sk, SOCK_DEAD))
1239 *timeo = schedule_timeout(*timeo);
1241 __set_current_state(TASK_RUNNING);
1242 remove_wait_queue(&nlk->wait, &wait);
1245 if (signal_pending(current)) {
1247 return sock_intr_errno(*timeo);
1251 netlink_skb_set_owner_r(skb, sk);
1255 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1259 netlink_deliver_tap(sock_net(sk), skb);
1261 skb_queue_tail(&sk->sk_receive_queue, skb);
1262 sk->sk_data_ready(sk);
1266 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1268 int len = __netlink_sendskb(sk, skb);
1274 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1280 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1284 WARN_ON(skb->sk != NULL);
1285 delta = skb->end - skb->tail;
1286 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1289 if (skb_shared(skb)) {
1290 struct sk_buff *nskb = skb_clone(skb, allocation);
1297 pskb_expand_head(skb, 0, -delta,
1298 (allocation & ~__GFP_DIRECT_RECLAIM) |
1299 __GFP_NOWARN | __GFP_NORETRY);
1303 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1307 struct netlink_sock *nlk = nlk_sk(sk);
1309 ret = -ECONNREFUSED;
1310 if (nlk->netlink_rcv != NULL) {
1312 netlink_skb_set_owner_r(skb, sk);
1313 NETLINK_CB(skb).sk = ssk;
1314 netlink_deliver_tap_kernel(sk, ssk, skb);
1315 nlk->netlink_rcv(skb);
1324 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1325 u32 portid, int nonblock)
1331 skb = netlink_trim(skb, gfp_any());
1333 timeo = sock_sndtimeo(ssk, nonblock);
1335 sk = netlink_getsockbyportid(ssk, portid);
1340 if (netlink_is_kernel(sk))
1341 return netlink_unicast_kernel(sk, skb, ssk);
1343 if (sk_filter(sk, skb)) {
1350 err = netlink_attachskb(sk, skb, &timeo, ssk);
1356 return netlink_sendskb(sk, skb);
1358 EXPORT_SYMBOL(netlink_unicast);
1360 int netlink_has_listeners(struct sock *sk, unsigned int group)
1363 struct listeners *listeners;
1365 BUG_ON(!netlink_is_kernel(sk));
1368 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1370 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1371 res = test_bit(group - 1, listeners->masks);
1377 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1379 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1381 struct netlink_sock *nlk = nlk_sk(sk);
1383 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1384 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1385 netlink_skb_set_owner_r(skb, sk);
1386 __netlink_sendskb(sk, skb);
1387 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1392 struct netlink_broadcast_data {
1393 struct sock *exclude_sk;
1398 int delivery_failure;
1402 struct sk_buff *skb, *skb2;
1403 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1407 static void do_one_broadcast(struct sock *sk,
1408 struct netlink_broadcast_data *p)
1410 struct netlink_sock *nlk = nlk_sk(sk);
1413 if (p->exclude_sk == sk)
1416 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1417 !test_bit(p->group - 1, nlk->groups))
1420 if (!net_eq(sock_net(sk), p->net)) {
1421 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1424 if (!peernet_has_id(sock_net(sk), p->net))
1427 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1433 netlink_overrun(sk);
1438 if (p->skb2 == NULL) {
1439 if (skb_shared(p->skb)) {
1440 p->skb2 = skb_clone(p->skb, p->allocation);
1442 p->skb2 = skb_get(p->skb);
1444 * skb ownership may have been set when
1445 * delivered to a previous socket.
1447 skb_orphan(p->skb2);
1450 if (p->skb2 == NULL) {
1451 netlink_overrun(sk);
1452 /* Clone failed. Notify ALL listeners. */
1454 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1455 p->delivery_failure = 1;
1458 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1463 if (sk_filter(sk, p->skb2)) {
1468 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1469 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1470 NETLINK_CB(p->skb2).nsid_is_set = true;
1471 val = netlink_broadcast_deliver(sk, p->skb2);
1473 netlink_overrun(sk);
1474 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1475 p->delivery_failure = 1;
1477 p->congested |= val;
1485 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1486 u32 group, gfp_t allocation,
1487 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1490 struct net *net = sock_net(ssk);
1491 struct netlink_broadcast_data info;
1494 skb = netlink_trim(skb, allocation);
1496 info.exclude_sk = ssk;
1498 info.portid = portid;
1501 info.delivery_failure = 0;
1504 info.allocation = allocation;
1507 info.tx_filter = filter;
1508 info.tx_data = filter_data;
1510 /* While we sleep in clone, do not allow to change socket list */
1512 netlink_lock_table();
1514 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1515 do_one_broadcast(sk, &info);
1519 netlink_unlock_table();
1521 if (info.delivery_failure) {
1522 kfree_skb(info.skb2);
1525 consume_skb(info.skb2);
1527 if (info.delivered) {
1528 if (info.congested && gfpflags_allow_blocking(allocation))
1534 EXPORT_SYMBOL(netlink_broadcast_filtered);
1536 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1537 u32 group, gfp_t allocation)
1539 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1542 EXPORT_SYMBOL(netlink_broadcast);
1544 struct netlink_set_err_data {
1545 struct sock *exclude_sk;
1551 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1553 struct netlink_sock *nlk = nlk_sk(sk);
1556 if (sk == p->exclude_sk)
1559 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1562 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1563 !test_bit(p->group - 1, nlk->groups))
1566 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1571 sk->sk_err = p->code;
1572 sk->sk_error_report(sk);
1578 * netlink_set_err - report error to broadcast listeners
1579 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1580 * @portid: the PORTID of a process that we want to skip (if any)
1581 * @group: the broadcast group that will notice the error
1582 * @code: error code, must be negative (as usual in kernelspace)
1584 * This function returns the number of broadcast listeners that have set the
1585 * NETLINK_NO_ENOBUFS socket option.
1587 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1589 struct netlink_set_err_data info;
1593 info.exclude_sk = ssk;
1594 info.portid = portid;
1596 /* sk->sk_err wants a positive error value */
1599 read_lock(&nl_table_lock);
1601 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1602 ret += do_one_set_err(sk, &info);
1604 read_unlock(&nl_table_lock);
1607 EXPORT_SYMBOL(netlink_set_err);
1609 /* must be called with netlink table grabbed */
1610 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1614 int old, new = !!is_new, subscriptions;
1616 old = test_bit(group - 1, nlk->groups);
1617 subscriptions = nlk->subscriptions - old + new;
1619 __set_bit(group - 1, nlk->groups);
1621 __clear_bit(group - 1, nlk->groups);
1622 netlink_update_subscriptions(&nlk->sk, subscriptions);
1623 netlink_update_listeners(&nlk->sk);
1626 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1627 char __user *optval, unsigned int optlen)
1629 struct sock *sk = sock->sk;
1630 struct netlink_sock *nlk = nlk_sk(sk);
1631 unsigned int val = 0;
1634 if (level != SOL_NETLINK)
1635 return -ENOPROTOOPT;
1637 if (optlen >= sizeof(int) &&
1638 get_user(val, (unsigned int __user *)optval))
1642 case NETLINK_PKTINFO:
1644 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1646 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1649 case NETLINK_ADD_MEMBERSHIP:
1650 case NETLINK_DROP_MEMBERSHIP: {
1651 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1653 err = netlink_realloc_groups(sk);
1656 if (!val || val - 1 >= nlk->ngroups)
1658 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1659 err = nlk->netlink_bind(sock_net(sk), val);
1663 netlink_table_grab();
1664 netlink_update_socket_mc(nlk, val,
1665 optname == NETLINK_ADD_MEMBERSHIP);
1666 netlink_table_ungrab();
1667 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1668 nlk->netlink_unbind(sock_net(sk), val);
1673 case NETLINK_BROADCAST_ERROR:
1675 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1677 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1680 case NETLINK_NO_ENOBUFS:
1682 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1683 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1684 wake_up_interruptible(&nlk->wait);
1686 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1690 case NETLINK_LISTEN_ALL_NSID:
1691 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1695 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1697 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1700 case NETLINK_CAP_ACK:
1702 nlk->flags |= NETLINK_F_CAP_ACK;
1704 nlk->flags &= ~NETLINK_F_CAP_ACK;
1707 case NETLINK_EXT_ACK:
1709 nlk->flags |= NETLINK_F_EXT_ACK;
1711 nlk->flags &= ~NETLINK_F_EXT_ACK;
1720 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1721 char __user *optval, int __user *optlen)
1723 struct sock *sk = sock->sk;
1724 struct netlink_sock *nlk = nlk_sk(sk);
1727 if (level != SOL_NETLINK)
1728 return -ENOPROTOOPT;
1730 if (get_user(len, optlen))
1736 case NETLINK_PKTINFO:
1737 if (len < sizeof(int))
1740 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1741 if (put_user(len, optlen) ||
1742 put_user(val, optval))
1746 case NETLINK_BROADCAST_ERROR:
1747 if (len < sizeof(int))
1750 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1751 if (put_user(len, optlen) ||
1752 put_user(val, optval))
1756 case NETLINK_NO_ENOBUFS:
1757 if (len < sizeof(int))
1760 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1761 if (put_user(len, optlen) ||
1762 put_user(val, optval))
1766 case NETLINK_LIST_MEMBERSHIPS: {
1767 int pos, idx, shift;
1770 netlink_lock_table();
1771 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1772 if (len - pos < sizeof(u32))
1775 idx = pos / sizeof(unsigned long);
1776 shift = (pos % sizeof(unsigned long)) * 8;
1777 if (put_user((u32)(nlk->groups[idx] >> shift),
1778 (u32 __user *)(optval + pos))) {
1783 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1785 netlink_unlock_table();
1788 case NETLINK_CAP_ACK:
1789 if (len < sizeof(int))
1792 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1793 if (put_user(len, optlen) ||
1794 put_user(val, optval))
1798 case NETLINK_EXT_ACK:
1799 if (len < sizeof(int))
1802 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1803 if (put_user(len, optlen) || put_user(val, optval))
1813 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1815 struct nl_pktinfo info;
1817 info.group = NETLINK_CB(skb).dst_group;
1818 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1821 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1822 struct sk_buff *skb)
1824 if (!NETLINK_CB(skb).nsid_is_set)
1827 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1828 &NETLINK_CB(skb).nsid);
1831 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1833 struct sock *sk = sock->sk;
1834 struct netlink_sock *nlk = nlk_sk(sk);
1835 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1838 struct sk_buff *skb;
1840 struct scm_cookie scm;
1841 u32 netlink_skb_flags = 0;
1843 if (msg->msg_flags&MSG_OOB)
1846 err = scm_send(sock, msg, &scm, true);
1850 if (msg->msg_namelen) {
1852 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1854 if (addr->nl_family != AF_NETLINK)
1856 dst_portid = addr->nl_pid;
1857 dst_group = ffs(addr->nl_groups);
1859 if ((dst_group || dst_portid) &&
1860 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1862 netlink_skb_flags |= NETLINK_SKB_DST;
1864 dst_portid = nlk->dst_portid;
1865 dst_group = nlk->dst_group;
1869 err = netlink_autobind(sock);
1873 /* Ensure nlk is hashed and visible. */
1878 if (len > sk->sk_sndbuf - 32)
1881 skb = netlink_alloc_large_skb(len, dst_group);
1885 NETLINK_CB(skb).portid = nlk->portid;
1886 NETLINK_CB(skb).dst_group = dst_group;
1887 NETLINK_CB(skb).creds = scm.creds;
1888 NETLINK_CB(skb).flags = netlink_skb_flags;
1891 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1896 err = security_netlink_send(sk, skb);
1903 refcount_inc(&skb->users);
1904 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1906 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1913 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1916 struct scm_cookie scm;
1917 struct sock *sk = sock->sk;
1918 struct netlink_sock *nlk = nlk_sk(sk);
1919 int noblock = flags&MSG_DONTWAIT;
1921 struct sk_buff *skb, *data_skb;
1929 skb = skb_recv_datagram(sk, flags, noblock, &err);
1935 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1936 if (unlikely(skb_shinfo(skb)->frag_list)) {
1938 * If this skb has a frag_list, then here that means that we
1939 * will have to use the frag_list skb's data for compat tasks
1940 * and the regular skb's data for normal (non-compat) tasks.
1942 * If we need to send the compat skb, assign it to the
1943 * 'data_skb' variable so that it will be used below for data
1944 * copying. We keep 'skb' for everything else, including
1945 * freeing both later.
1947 if (flags & MSG_CMSG_COMPAT)
1948 data_skb = skb_shinfo(skb)->frag_list;
1952 /* Record the max length of recvmsg() calls for future allocations */
1953 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1954 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1955 SKB_WITH_OVERHEAD(32768));
1957 copied = data_skb->len;
1959 msg->msg_flags |= MSG_TRUNC;
1963 skb_reset_transport_header(data_skb);
1964 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1966 if (msg->msg_name) {
1967 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1968 addr->nl_family = AF_NETLINK;
1970 addr->nl_pid = NETLINK_CB(skb).portid;
1971 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1972 msg->msg_namelen = sizeof(*addr);
1975 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1976 netlink_cmsg_recv_pktinfo(msg, skb);
1977 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1978 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1980 memset(&scm, 0, sizeof(scm));
1981 scm.creds = *NETLINK_CREDS(skb);
1982 if (flags & MSG_TRUNC)
1983 copied = data_skb->len;
1985 skb_free_datagram(sk, skb);
1987 if (nlk->cb_running &&
1988 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1989 ret = netlink_dump(sk);
1992 sk->sk_error_report(sk);
1996 scm_recv(sock, msg, &scm, flags);
1998 netlink_rcv_wake(sk);
1999 return err ? : copied;
2002 static void netlink_data_ready(struct sock *sk)
2008 * We export these functions to other modules. They provide a
2009 * complete set of kernel non-blocking support for message
2014 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2015 struct netlink_kernel_cfg *cfg)
2017 struct socket *sock;
2019 struct netlink_sock *nlk;
2020 struct listeners *listeners = NULL;
2021 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2022 unsigned int groups;
2026 if (unit < 0 || unit >= MAX_LINKS)
2029 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2032 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2033 goto out_sock_release_nosk;
2037 if (!cfg || cfg->groups < 32)
2040 groups = cfg->groups;
2042 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2044 goto out_sock_release;
2046 sk->sk_data_ready = netlink_data_ready;
2047 if (cfg && cfg->input)
2048 nlk_sk(sk)->netlink_rcv = cfg->input;
2050 if (netlink_insert(sk, 0))
2051 goto out_sock_release;
2054 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2056 netlink_table_grab();
2057 if (!nl_table[unit].registered) {
2058 nl_table[unit].groups = groups;
2059 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2060 nl_table[unit].cb_mutex = cb_mutex;
2061 nl_table[unit].module = module;
2063 nl_table[unit].bind = cfg->bind;
2064 nl_table[unit].unbind = cfg->unbind;
2065 nl_table[unit].flags = cfg->flags;
2067 nl_table[unit].compare = cfg->compare;
2069 nl_table[unit].registered = 1;
2072 nl_table[unit].registered++;
2074 netlink_table_ungrab();
2079 netlink_kernel_release(sk);
2082 out_sock_release_nosk:
2086 EXPORT_SYMBOL(__netlink_kernel_create);
2089 netlink_kernel_release(struct sock *sk)
2091 if (sk == NULL || sk->sk_socket == NULL)
2094 sock_release(sk->sk_socket);
2096 EXPORT_SYMBOL(netlink_kernel_release);
2098 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2100 struct listeners *new, *old;
2101 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2106 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2107 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2110 old = nl_deref_protected(tbl->listeners);
2111 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2112 rcu_assign_pointer(tbl->listeners, new);
2114 kfree_rcu(old, rcu);
2116 tbl->groups = groups;
2122 * netlink_change_ngroups - change number of multicast groups
2124 * This changes the number of multicast groups that are available
2125 * on a certain netlink family. Note that it is not possible to
2126 * change the number of groups to below 32. Also note that it does
2127 * not implicitly call netlink_clear_multicast_users() when the
2128 * number of groups is reduced.
2130 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2131 * @groups: The new number of groups.
2133 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2137 netlink_table_grab();
2138 err = __netlink_change_ngroups(sk, groups);
2139 netlink_table_ungrab();
2144 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2147 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2149 sk_for_each_bound(sk, &tbl->mc_list)
2150 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2154 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2156 struct nlmsghdr *nlh;
2157 int size = nlmsg_msg_size(len);
2159 nlh = skb_put(skb, NLMSG_ALIGN(size));
2160 nlh->nlmsg_type = type;
2161 nlh->nlmsg_len = size;
2162 nlh->nlmsg_flags = flags;
2163 nlh->nlmsg_pid = portid;
2164 nlh->nlmsg_seq = seq;
2165 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2166 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2169 EXPORT_SYMBOL(__nlmsg_put);
2172 * It looks a bit ugly.
2173 * It would be better to create kernel thread.
2176 static int netlink_dump(struct sock *sk)
2178 struct netlink_sock *nlk = nlk_sk(sk);
2179 struct netlink_callback *cb;
2180 struct sk_buff *skb = NULL;
2181 struct nlmsghdr *nlh;
2182 struct module *module;
2187 mutex_lock(nlk->cb_mutex);
2188 if (!nlk->cb_running) {
2193 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2196 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2197 * required, but it makes sense to _attempt_ a 16K bytes allocation
2198 * to reduce number of system calls on dump operations, if user
2199 * ever provided a big enough buffer.
2202 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2204 if (alloc_min_size < nlk->max_recvmsg_len) {
2205 alloc_size = nlk->max_recvmsg_len;
2206 skb = alloc_skb(alloc_size,
2207 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2208 __GFP_NOWARN | __GFP_NORETRY);
2211 alloc_size = alloc_min_size;
2212 skb = alloc_skb(alloc_size, GFP_KERNEL);
2217 /* Trim skb to allocated size. User is expected to provide buffer as
2218 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2219 * netlink_recvmsg())). dump will pack as many smaller messages as
2220 * could fit within the allocated skb. skb is typically allocated
2221 * with larger space than required (could be as much as near 2x the
2222 * requested size with align to next power of 2 approach). Allowing
2223 * dump to use the excess space makes it difficult for a user to have a
2224 * reasonable static buffer based on the expected largest dump of a
2225 * single netdev. The outcome is MSG_TRUNC error.
2227 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2228 netlink_skb_set_owner_r(skb, sk);
2230 if (nlk->dump_done_errno > 0)
2231 nlk->dump_done_errno = cb->dump(skb, cb);
2233 if (nlk->dump_done_errno > 0 ||
2234 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2235 mutex_unlock(nlk->cb_mutex);
2237 if (sk_filter(sk, skb))
2240 __netlink_sendskb(sk, skb);
2244 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
2245 sizeof(nlk->dump_done_errno), NLM_F_MULTI);
2249 nl_dump_check_consistent(cb, nlh);
2251 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
2252 sizeof(nlk->dump_done_errno));
2254 if (sk_filter(sk, skb))
2257 __netlink_sendskb(sk, skb);
2262 nlk->cb_running = false;
2263 module = cb->module;
2265 mutex_unlock(nlk->cb_mutex);
2271 mutex_unlock(nlk->cb_mutex);
2276 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2277 const struct nlmsghdr *nlh,
2278 struct netlink_dump_control *control)
2280 struct netlink_callback *cb;
2282 struct netlink_sock *nlk;
2285 refcount_inc(&skb->users);
2287 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2289 ret = -ECONNREFUSED;
2294 mutex_lock(nlk->cb_mutex);
2295 /* A dump is in progress... */
2296 if (nlk->cb_running) {
2300 /* add reference of module which cb->dump belongs to */
2301 if (!try_module_get(control->module)) {
2302 ret = -EPROTONOSUPPORT;
2307 memset(cb, 0, sizeof(*cb));
2308 cb->dump = control->dump;
2309 cb->done = control->done;
2311 cb->data = control->data;
2312 cb->module = control->module;
2313 cb->min_dump_alloc = control->min_dump_alloc;
2316 if (control->start) {
2317 ret = control->start(cb);
2322 nlk->cb_running = true;
2323 nlk->dump_done_errno = INT_MAX;
2325 mutex_unlock(nlk->cb_mutex);
2327 ret = netlink_dump(sk);
2334 /* We successfully started a dump, by returning -EINTR we
2335 * signal not to send ACK even if it was requested.
2340 module_put(control->module);
2343 mutex_unlock(nlk->cb_mutex);
2348 EXPORT_SYMBOL(__netlink_dump_start);
2350 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2351 const struct netlink_ext_ack *extack)
2353 struct sk_buff *skb;
2354 struct nlmsghdr *rep;
2355 struct nlmsgerr *errmsg;
2356 size_t payload = sizeof(*errmsg);
2358 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2359 unsigned int flags = 0;
2360 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK;
2362 /* Error messages get the original request appened, unless the user
2363 * requests to cap the error message, and get extra error data if
2366 if (nlk_has_extack && extack && extack->_msg)
2367 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2370 if (!(nlk->flags & NETLINK_F_CAP_ACK))
2371 payload += nlmsg_len(nlh);
2373 flags |= NLM_F_CAPPED;
2374 if (nlk_has_extack && extack && extack->bad_attr)
2375 tlvlen += nla_total_size(sizeof(u32));
2377 flags |= NLM_F_CAPPED;
2379 if (nlk_has_extack && extack && extack->cookie_len)
2380 tlvlen += nla_total_size(extack->cookie_len);
2384 flags |= NLM_F_ACK_TLVS;
2386 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2388 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
2389 NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk);
2393 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2394 NLMSG_ERROR, payload, flags);
2395 errmsg = nlmsg_data(rep);
2396 errmsg->error = err;
2397 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2399 if (nlk_has_extack && extack) {
2401 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2405 if (extack->bad_attr &&
2406 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2407 (u8 *)extack->bad_attr >= in_skb->data +
2409 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2410 (u8 *)extack->bad_attr -
2413 if (extack->cookie_len)
2414 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2420 nlmsg_end(skb, rep);
2422 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2424 EXPORT_SYMBOL(netlink_ack);
2426 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2428 struct netlink_ext_ack *))
2430 struct netlink_ext_ack extack;
2431 struct nlmsghdr *nlh;
2434 while (skb->len >= nlmsg_total_size(0)) {
2437 memset(&extack, 0, sizeof(extack));
2438 nlh = nlmsg_hdr(skb);
2441 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2444 /* Only requests are handled by the kernel */
2445 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2448 /* Skip control messages */
2449 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2452 err = cb(skb, nlh, &extack);
2457 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2458 netlink_ack(skb, nlh, err, &extack);
2461 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2462 if (msglen > skb->len)
2464 skb_pull(skb, msglen);
2469 EXPORT_SYMBOL(netlink_rcv_skb);
2472 * nlmsg_notify - send a notification netlink message
2473 * @sk: netlink socket to use
2474 * @skb: notification message
2475 * @portid: destination netlink portid for reports or 0
2476 * @group: destination multicast group or 0
2477 * @report: 1 to report back, 0 to disable
2478 * @flags: allocation flags
2480 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2481 unsigned int group, int report, gfp_t flags)
2486 int exclude_portid = 0;
2489 refcount_inc(&skb->users);
2490 exclude_portid = portid;
2493 /* errors reported via destination sk->sk_err, but propagate
2494 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2495 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2501 err2 = nlmsg_unicast(sk, skb, portid);
2502 if (!err || err == -ESRCH)
2508 EXPORT_SYMBOL(nlmsg_notify);
2510 #ifdef CONFIG_PROC_FS
2511 struct nl_seq_iter {
2512 struct seq_net_private p;
2513 struct rhashtable_iter hti;
2517 static int netlink_walk_start(struct nl_seq_iter *iter)
2521 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
2524 iter->link = MAX_LINKS;
2528 rhashtable_walk_start(&iter->hti);
2533 static void netlink_walk_stop(struct nl_seq_iter *iter)
2535 rhashtable_walk_stop(&iter->hti);
2536 rhashtable_walk_exit(&iter->hti);
2539 static void *__netlink_seq_next(struct seq_file *seq)
2541 struct nl_seq_iter *iter = seq->private;
2542 struct netlink_sock *nlk;
2548 nlk = rhashtable_walk_next(&iter->hti);
2551 if (PTR_ERR(nlk) == -EAGAIN)
2560 netlink_walk_stop(iter);
2561 if (++iter->link >= MAX_LINKS)
2564 err = netlink_walk_start(iter);
2566 return ERR_PTR(err);
2568 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2573 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2575 struct nl_seq_iter *iter = seq->private;
2576 void *obj = SEQ_START_TOKEN;
2582 err = netlink_walk_start(iter);
2584 return ERR_PTR(err);
2586 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2587 obj = __netlink_seq_next(seq);
2592 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2595 return __netlink_seq_next(seq);
2598 static void netlink_seq_stop(struct seq_file *seq, void *v)
2600 struct nl_seq_iter *iter = seq->private;
2602 if (iter->link >= MAX_LINKS)
2605 netlink_walk_stop(iter);
2609 static int netlink_seq_show(struct seq_file *seq, void *v)
2611 if (v == SEQ_START_TOKEN) {
2613 "sk Eth Pid Groups "
2614 "Rmem Wmem Dump Locks Drops Inode\n");
2617 struct netlink_sock *nlk = nlk_sk(s);
2619 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8d %-8lu\n",
2623 nlk->groups ? (u32)nlk->groups[0] : 0,
2624 sk_rmem_alloc_get(s),
2625 sk_wmem_alloc_get(s),
2627 refcount_read(&s->sk_refcnt),
2628 atomic_read(&s->sk_drops),
2636 static const struct seq_operations netlink_seq_ops = {
2637 .start = netlink_seq_start,
2638 .next = netlink_seq_next,
2639 .stop = netlink_seq_stop,
2640 .show = netlink_seq_show,
2644 int netlink_register_notifier(struct notifier_block *nb)
2646 return blocking_notifier_chain_register(&netlink_chain, nb);
2648 EXPORT_SYMBOL(netlink_register_notifier);
2650 int netlink_unregister_notifier(struct notifier_block *nb)
2652 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2654 EXPORT_SYMBOL(netlink_unregister_notifier);
2656 static const struct proto_ops netlink_ops = {
2657 .family = PF_NETLINK,
2658 .owner = THIS_MODULE,
2659 .release = netlink_release,
2660 .bind = netlink_bind,
2661 .connect = netlink_connect,
2662 .socketpair = sock_no_socketpair,
2663 .accept = sock_no_accept,
2664 .getname = netlink_getname,
2665 .poll = datagram_poll,
2666 .ioctl = netlink_ioctl,
2667 .listen = sock_no_listen,
2668 .shutdown = sock_no_shutdown,
2669 .setsockopt = netlink_setsockopt,
2670 .getsockopt = netlink_getsockopt,
2671 .sendmsg = netlink_sendmsg,
2672 .recvmsg = netlink_recvmsg,
2673 .mmap = sock_no_mmap,
2674 .sendpage = sock_no_sendpage,
2677 static const struct net_proto_family netlink_family_ops = {
2678 .family = PF_NETLINK,
2679 .create = netlink_create,
2680 .owner = THIS_MODULE, /* for consistency 8) */
2683 static int __net_init netlink_net_init(struct net *net)
2685 #ifdef CONFIG_PROC_FS
2686 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops,
2687 sizeof(struct nl_seq_iter)))
2693 static void __net_exit netlink_net_exit(struct net *net)
2695 #ifdef CONFIG_PROC_FS
2696 remove_proc_entry("netlink", net->proc_net);
2700 static void __init netlink_add_usersock_entry(void)
2702 struct listeners *listeners;
2705 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2707 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2709 netlink_table_grab();
2711 nl_table[NETLINK_USERSOCK].groups = groups;
2712 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2713 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2714 nl_table[NETLINK_USERSOCK].registered = 1;
2715 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2717 netlink_table_ungrab();
2720 static struct pernet_operations __net_initdata netlink_net_ops = {
2721 .init = netlink_net_init,
2722 .exit = netlink_net_exit,
2725 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2727 const struct netlink_sock *nlk = data;
2728 struct netlink_compare_arg arg;
2730 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2731 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2734 static const struct rhashtable_params netlink_rhashtable_params = {
2735 .head_offset = offsetof(struct netlink_sock, node),
2736 .key_len = netlink_compare_arg_len,
2737 .obj_hashfn = netlink_hash,
2738 .obj_cmpfn = netlink_compare,
2739 .automatic_shrinking = true,
2742 static int __init netlink_proto_init(void)
2745 int err = proto_register(&netlink_proto, 0);
2750 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2752 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2756 for (i = 0; i < MAX_LINKS; i++) {
2757 if (rhashtable_init(&nl_table[i].hash,
2758 &netlink_rhashtable_params) < 0) {
2760 rhashtable_destroy(&nl_table[i].hash);
2766 netlink_add_usersock_entry();
2768 sock_register(&netlink_family_ops);
2769 register_pernet_subsys(&netlink_net_ops);
2770 register_pernet_subsys(&netlink_tap_net_ops);
2771 /* The netlink device handler may be needed early. */
2776 panic("netlink_init: Cannot allocate nl_table\n");
2779 core_initcall(netlink_proto_init);