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>
71 #include <net/netlink.h>
73 #include "af_netlink.h"
77 unsigned long masks[0];
81 #define NETLINK_S_CONGESTED 0x0
83 static inline int netlink_is_kernel(struct sock *sk)
85 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
88 struct netlink_table *nl_table __read_mostly;
89 EXPORT_SYMBOL_GPL(nl_table);
91 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
93 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
95 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
98 "nlk_cb_mutex-USERSOCK",
99 "nlk_cb_mutex-FIREWALL",
100 "nlk_cb_mutex-SOCK_DIAG",
101 "nlk_cb_mutex-NFLOG",
103 "nlk_cb_mutex-SELINUX",
104 "nlk_cb_mutex-ISCSI",
105 "nlk_cb_mutex-AUDIT",
106 "nlk_cb_mutex-FIB_LOOKUP",
107 "nlk_cb_mutex-CONNECTOR",
108 "nlk_cb_mutex-NETFILTER",
109 "nlk_cb_mutex-IP6_FW",
110 "nlk_cb_mutex-DNRTMSG",
111 "nlk_cb_mutex-KOBJECT_UEVENT",
112 "nlk_cb_mutex-GENERIC",
114 "nlk_cb_mutex-SCSITRANSPORT",
115 "nlk_cb_mutex-ECRYPTFS",
117 "nlk_cb_mutex-CRYPTO",
128 "nlk_cb_mutex-MAX_LINKS"
131 static int netlink_dump(struct sock *sk);
132 static void netlink_skb_destructor(struct sk_buff *skb);
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);
150 static DEFINE_SPINLOCK(netlink_tap_lock);
151 static struct list_head netlink_tap_all __read_mostly;
153 static const struct rhashtable_params netlink_rhashtable_params;
155 static inline u32 netlink_group_mask(u32 group)
159 return group ? 1 << (group - 1) : 0;
162 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
165 unsigned int len = skb_end_offset(skb);
168 new = alloc_skb(len, gfp_mask);
172 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
173 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
174 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
176 skb_put_data(new, skb->data, len);
180 int netlink_add_tap(struct netlink_tap *nt)
182 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
185 spin_lock(&netlink_tap_lock);
186 list_add_rcu(&nt->list, &netlink_tap_all);
187 spin_unlock(&netlink_tap_lock);
189 __module_get(nt->module);
193 EXPORT_SYMBOL_GPL(netlink_add_tap);
195 static int __netlink_remove_tap(struct netlink_tap *nt)
198 struct netlink_tap *tmp;
200 spin_lock(&netlink_tap_lock);
202 list_for_each_entry(tmp, &netlink_tap_all, list) {
204 list_del_rcu(&nt->list);
210 pr_warn("__netlink_remove_tap: %p not found\n", nt);
212 spin_unlock(&netlink_tap_lock);
215 module_put(nt->module);
217 return found ? 0 : -ENODEV;
220 int netlink_remove_tap(struct netlink_tap *nt)
224 ret = __netlink_remove_tap(nt);
229 EXPORT_SYMBOL_GPL(netlink_remove_tap);
231 static bool netlink_filter_tap(const struct sk_buff *skb)
233 struct sock *sk = skb->sk;
235 /* We take the more conservative approach and
236 * whitelist socket protocols that may pass.
238 switch (sk->sk_protocol) {
240 case NETLINK_USERSOCK:
241 case NETLINK_SOCK_DIAG:
244 case NETLINK_FIB_LOOKUP:
245 case NETLINK_NETFILTER:
246 case NETLINK_GENERIC:
253 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
254 struct net_device *dev)
256 struct sk_buff *nskb;
257 struct sock *sk = skb->sk;
260 if (!net_eq(dev_net(dev), sock_net(sk)))
265 if (is_vmalloc_addr(skb->head))
266 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
268 nskb = skb_clone(skb, GFP_ATOMIC);
271 nskb->protocol = htons((u16) sk->sk_protocol);
272 nskb->pkt_type = netlink_is_kernel(sk) ?
273 PACKET_KERNEL : PACKET_USER;
274 skb_reset_network_header(nskb);
275 ret = dev_queue_xmit(nskb);
276 if (unlikely(ret > 0))
277 ret = net_xmit_errno(ret);
284 static void __netlink_deliver_tap(struct sk_buff *skb)
287 struct netlink_tap *tmp;
289 if (!netlink_filter_tap(skb))
292 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
293 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
299 static void netlink_deliver_tap(struct sk_buff *skb)
303 if (unlikely(!list_empty(&netlink_tap_all)))
304 __netlink_deliver_tap(skb);
309 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
312 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
313 netlink_deliver_tap(skb);
316 static void netlink_overrun(struct sock *sk)
318 struct netlink_sock *nlk = nlk_sk(sk);
320 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
321 if (!test_and_set_bit(NETLINK_S_CONGESTED,
322 &nlk_sk(sk)->state)) {
323 sk->sk_err = ENOBUFS;
324 sk->sk_error_report(sk);
327 atomic_inc(&sk->sk_drops);
330 static void netlink_rcv_wake(struct sock *sk)
332 struct netlink_sock *nlk = nlk_sk(sk);
334 if (skb_queue_empty(&sk->sk_receive_queue))
335 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
336 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
337 wake_up_interruptible(&nlk->wait);
340 static void netlink_skb_destructor(struct sk_buff *skb)
342 if (is_vmalloc_addr(skb->head)) {
344 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
353 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
355 WARN_ON(skb->sk != NULL);
357 skb->destructor = netlink_skb_destructor;
358 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
359 sk_mem_charge(sk, skb->truesize);
362 static void netlink_sock_destruct(struct sock *sk)
364 struct netlink_sock *nlk = nlk_sk(sk);
366 if (nlk->cb_running) {
368 nlk->cb.done(&nlk->cb);
369 module_put(nlk->cb.module);
370 kfree_skb(nlk->cb.skb);
373 skb_queue_purge(&sk->sk_receive_queue);
375 if (!sock_flag(sk, SOCK_DEAD)) {
376 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
380 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
381 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
382 WARN_ON(nlk_sk(sk)->groups);
385 static void netlink_sock_destruct_work(struct work_struct *work)
387 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
393 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
394 * SMP. Look, when several writers sleep and reader wakes them up, all but one
395 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
396 * this, _but_ remember, it adds useless work on UP machines.
399 void netlink_table_grab(void)
400 __acquires(nl_table_lock)
404 write_lock_irq(&nl_table_lock);
406 if (atomic_read(&nl_table_users)) {
407 DECLARE_WAITQUEUE(wait, current);
409 add_wait_queue_exclusive(&nl_table_wait, &wait);
411 set_current_state(TASK_UNINTERRUPTIBLE);
412 if (atomic_read(&nl_table_users) == 0)
414 write_unlock_irq(&nl_table_lock);
416 write_lock_irq(&nl_table_lock);
419 __set_current_state(TASK_RUNNING);
420 remove_wait_queue(&nl_table_wait, &wait);
424 void netlink_table_ungrab(void)
425 __releases(nl_table_lock)
427 write_unlock_irq(&nl_table_lock);
428 wake_up(&nl_table_wait);
432 netlink_lock_table(void)
436 /* read_lock() synchronizes us to netlink_table_grab */
438 read_lock_irqsave(&nl_table_lock, flags);
439 atomic_inc(&nl_table_users);
440 read_unlock_irqrestore(&nl_table_lock, flags);
444 netlink_unlock_table(void)
446 if (atomic_dec_and_test(&nl_table_users))
447 wake_up(&nl_table_wait);
450 struct netlink_compare_arg
456 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
457 #define netlink_compare_arg_len \
458 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
460 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
463 const struct netlink_compare_arg *x = arg->key;
464 const struct netlink_sock *nlk = ptr;
466 return nlk->portid != x->portid ||
467 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
470 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
471 struct net *net, u32 portid)
473 memset(arg, 0, sizeof(*arg));
474 write_pnet(&arg->pnet, net);
475 arg->portid = portid;
478 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
481 struct netlink_compare_arg arg;
483 netlink_compare_arg_init(&arg, net, portid);
484 return rhashtable_lookup_fast(&table->hash, &arg,
485 netlink_rhashtable_params);
488 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
490 struct netlink_compare_arg arg;
492 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
493 return rhashtable_lookup_insert_key(&table->hash, &arg,
495 netlink_rhashtable_params);
498 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
500 struct netlink_table *table = &nl_table[protocol];
504 sk = __netlink_lookup(table, portid, net);
512 static const struct proto_ops netlink_ops;
515 netlink_update_listeners(struct sock *sk)
517 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
520 struct listeners *listeners;
522 listeners = nl_deref_protected(tbl->listeners);
526 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
528 sk_for_each_bound(sk, &tbl->mc_list) {
529 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
530 mask |= nlk_sk(sk)->groups[i];
532 listeners->masks[i] = mask;
534 /* this function is only called with the netlink table "grabbed", which
535 * makes sure updates are visible before bind or setsockopt return. */
538 static int netlink_insert(struct sock *sk, u32 portid)
540 struct netlink_table *table = &nl_table[sk->sk_protocol];
545 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
546 if (nlk_sk(sk)->bound)
550 if (BITS_PER_LONG > 32 &&
551 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
554 nlk_sk(sk)->portid = portid;
557 err = __netlink_insert(table, sk);
559 /* In case the hashtable backend returns with -EBUSY
560 * from here, it must not escape to the caller.
562 if (unlikely(err == -EBUSY))
570 /* We need to ensure that the socket is hashed and visible. */
572 /* Paired with lockless reads from netlink_bind(),
573 * netlink_connect() and netlink_sendmsg().
575 WRITE_ONCE(nlk_sk(sk)->bound, portid);
582 static void netlink_remove(struct sock *sk)
584 struct netlink_table *table;
586 table = &nl_table[sk->sk_protocol];
587 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
588 netlink_rhashtable_params)) {
589 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
593 netlink_table_grab();
594 if (nlk_sk(sk)->subscriptions) {
595 __sk_del_bind_node(sk);
596 netlink_update_listeners(sk);
598 if (sk->sk_protocol == NETLINK_GENERIC)
599 atomic_inc(&genl_sk_destructing_cnt);
600 netlink_table_ungrab();
603 static struct proto netlink_proto = {
605 .owner = THIS_MODULE,
606 .obj_size = sizeof(struct netlink_sock),
609 static int __netlink_create(struct net *net, struct socket *sock,
610 struct mutex *cb_mutex, int protocol,
614 struct netlink_sock *nlk;
616 sock->ops = &netlink_ops;
618 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
622 sock_init_data(sock, sk);
626 nlk->cb_mutex = cb_mutex;
628 nlk->cb_mutex = &nlk->cb_def_mutex;
629 mutex_init(nlk->cb_mutex);
630 lockdep_set_class_and_name(nlk->cb_mutex,
631 nlk_cb_mutex_keys + protocol,
632 nlk_cb_mutex_key_strings[protocol]);
634 init_waitqueue_head(&nlk->wait);
636 sk->sk_destruct = netlink_sock_destruct;
637 sk->sk_protocol = protocol;
641 static int netlink_create(struct net *net, struct socket *sock, int protocol,
644 struct module *module = NULL;
645 struct mutex *cb_mutex;
646 struct netlink_sock *nlk;
647 int (*bind)(struct net *net, int group);
648 void (*unbind)(struct net *net, int group);
651 sock->state = SS_UNCONNECTED;
653 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
654 return -ESOCKTNOSUPPORT;
656 if (protocol < 0 || protocol >= MAX_LINKS)
657 return -EPROTONOSUPPORT;
658 protocol = array_index_nospec(protocol, MAX_LINKS);
660 netlink_lock_table();
661 #ifdef CONFIG_MODULES
662 if (!nl_table[protocol].registered) {
663 netlink_unlock_table();
664 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
665 netlink_lock_table();
668 if (nl_table[protocol].registered &&
669 try_module_get(nl_table[protocol].module))
670 module = nl_table[protocol].module;
672 err = -EPROTONOSUPPORT;
673 cb_mutex = nl_table[protocol].cb_mutex;
674 bind = nl_table[protocol].bind;
675 unbind = nl_table[protocol].unbind;
676 netlink_unlock_table();
681 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
686 sock_prot_inuse_add(net, &netlink_proto, 1);
689 nlk = nlk_sk(sock->sk);
690 nlk->module = module;
691 nlk->netlink_bind = bind;
692 nlk->netlink_unbind = unbind;
701 static void deferred_put_nlk_sk(struct rcu_head *head)
703 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
704 struct sock *sk = &nlk->sk;
709 if (!refcount_dec_and_test(&sk->sk_refcnt))
712 if (nlk->cb_running && nlk->cb.done) {
713 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
714 schedule_work(&nlk->work);
721 static int netlink_release(struct socket *sock)
723 struct sock *sk = sock->sk;
724 struct netlink_sock *nlk;
734 * OK. Socket is unlinked, any packets that arrive now
738 /* must not acquire netlink_table_lock in any way again before unbind
739 * and notifying genetlink is done as otherwise it might deadlock
741 if (nlk->netlink_unbind) {
744 for (i = 0; i < nlk->ngroups; i++)
745 if (test_bit(i, nlk->groups))
746 nlk->netlink_unbind(sock_net(sk), i + 1);
748 if (sk->sk_protocol == NETLINK_GENERIC &&
749 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
750 wake_up(&genl_sk_destructing_waitq);
753 wake_up_interruptible_all(&nlk->wait);
755 skb_queue_purge(&sk->sk_write_queue);
757 if (nlk->portid && nlk->bound) {
758 struct netlink_notify n = {
760 .protocol = sk->sk_protocol,
761 .portid = nlk->portid,
763 blocking_notifier_call_chain(&netlink_chain,
764 NETLINK_URELEASE, &n);
767 module_put(nlk->module);
769 if (netlink_is_kernel(sk)) {
770 netlink_table_grab();
771 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
772 if (--nl_table[sk->sk_protocol].registered == 0) {
773 struct listeners *old;
775 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
776 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
778 nl_table[sk->sk_protocol].module = NULL;
779 nl_table[sk->sk_protocol].bind = NULL;
780 nl_table[sk->sk_protocol].unbind = NULL;
781 nl_table[sk->sk_protocol].flags = 0;
782 nl_table[sk->sk_protocol].registered = 0;
784 netlink_table_ungrab();
788 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
790 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
794 static int netlink_autobind(struct socket *sock)
796 struct sock *sk = sock->sk;
797 struct net *net = sock_net(sk);
798 struct netlink_table *table = &nl_table[sk->sk_protocol];
799 s32 portid = task_tgid_vnr(current);
807 ok = !__netlink_lookup(table, portid, net);
810 /* Bind collision, search negative portid values. */
812 /* rover will be in range [S32_MIN, -4097] */
813 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
814 else if (rover >= -4096)
820 err = netlink_insert(sk, portid);
821 if (err == -EADDRINUSE)
824 /* If 2 threads race to autobind, that is fine. */
832 * __netlink_ns_capable - General netlink message capability test
833 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
834 * @user_ns: The user namespace of the capability to use
835 * @cap: The capability to use
837 * Test to see if the opener of the socket we received the message
838 * from had when the netlink socket was created and the sender of the
839 * message has has the capability @cap in the user namespace @user_ns.
841 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
842 struct user_namespace *user_ns, int cap)
844 return ((nsp->flags & NETLINK_SKB_DST) ||
845 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
846 ns_capable(user_ns, cap);
848 EXPORT_SYMBOL(__netlink_ns_capable);
851 * netlink_ns_capable - General netlink message capability test
852 * @skb: socket buffer holding a netlink command from userspace
853 * @user_ns: The user namespace of the capability to use
854 * @cap: The capability to use
856 * Test to see if the opener of the socket we received the message
857 * from had when the netlink socket was created and the sender of the
858 * message has has the capability @cap in the user namespace @user_ns.
860 bool netlink_ns_capable(const struct sk_buff *skb,
861 struct user_namespace *user_ns, int cap)
863 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
865 EXPORT_SYMBOL(netlink_ns_capable);
868 * netlink_capable - Netlink global message capability test
869 * @skb: socket buffer holding a netlink command from userspace
870 * @cap: The capability to use
872 * Test to see if the opener of the socket we received the message
873 * from had when the netlink socket was created and the sender of the
874 * message has has the capability @cap in all user namespaces.
876 bool netlink_capable(const struct sk_buff *skb, int cap)
878 return netlink_ns_capable(skb, &init_user_ns, cap);
880 EXPORT_SYMBOL(netlink_capable);
883 * netlink_net_capable - Netlink network namespace message capability test
884 * @skb: socket buffer holding a netlink command from userspace
885 * @cap: The capability to use
887 * Test to see if the opener of the socket we received the message
888 * from had when the netlink socket was created and the sender of the
889 * message has has the capability @cap over the network namespace of
890 * the socket we received the message from.
892 bool netlink_net_capable(const struct sk_buff *skb, int cap)
894 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
896 EXPORT_SYMBOL(netlink_net_capable);
898 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
900 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
901 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
905 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
907 struct netlink_sock *nlk = nlk_sk(sk);
909 if (nlk->subscriptions && !subscriptions)
910 __sk_del_bind_node(sk);
911 else if (!nlk->subscriptions && subscriptions)
912 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
913 nlk->subscriptions = subscriptions;
916 static int netlink_realloc_groups(struct sock *sk)
918 struct netlink_sock *nlk = nlk_sk(sk);
920 unsigned long *new_groups;
923 netlink_table_grab();
925 groups = nl_table[sk->sk_protocol].groups;
926 if (!nl_table[sk->sk_protocol].registered) {
931 if (nlk->ngroups >= groups)
934 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
935 if (new_groups == NULL) {
939 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
940 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
942 nlk->groups = new_groups;
943 nlk->ngroups = groups;
945 netlink_table_ungrab();
949 static void netlink_undo_bind(int group, long unsigned int groups,
952 struct netlink_sock *nlk = nlk_sk(sk);
955 if (!nlk->netlink_unbind)
958 for (undo = 0; undo < group; undo++)
959 if (test_bit(undo, &groups))
960 nlk->netlink_unbind(sock_net(sk), undo + 1);
963 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
966 struct sock *sk = sock->sk;
967 struct net *net = sock_net(sk);
968 struct netlink_sock *nlk = nlk_sk(sk);
969 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
971 long unsigned int groups = nladdr->nl_groups;
974 if (addr_len < sizeof(struct sockaddr_nl))
977 if (nladdr->nl_family != AF_NETLINK)
980 /* Only superuser is allowed to listen multicasts */
982 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
984 err = netlink_realloc_groups(sk);
989 if (nlk->ngroups == 0)
991 else if (nlk->ngroups < 8*sizeof(groups))
992 groups &= (1UL << nlk->ngroups) - 1;
994 /* Paired with WRITE_ONCE() in netlink_insert() */
995 bound = READ_ONCE(nlk->bound);
997 /* Ensure nlk->portid is up-to-date. */
1000 if (nladdr->nl_pid != nlk->portid)
1004 netlink_lock_table();
1005 if (nlk->netlink_bind && groups) {
1008 /* nl_groups is a u32, so cap the maximum groups we can bind */
1009 for (group = 0; group < BITS_PER_TYPE(u32); group++) {
1010 if (!test_bit(group, &groups))
1012 err = nlk->netlink_bind(net, group + 1);
1015 netlink_undo_bind(group, groups, sk);
1020 /* No need for barriers here as we return to user-space without
1021 * using any of the bound attributes.
1024 err = nladdr->nl_pid ?
1025 netlink_insert(sk, nladdr->nl_pid) :
1026 netlink_autobind(sock);
1028 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
1033 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1035 netlink_unlock_table();
1037 netlink_table_grab();
1038 netlink_update_subscriptions(sk, nlk->subscriptions +
1040 hweight32(nlk->groups[0]));
1041 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1042 netlink_update_listeners(sk);
1043 netlink_table_ungrab();
1048 netlink_unlock_table();
1052 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1053 int alen, int flags)
1056 struct sock *sk = sock->sk;
1057 struct netlink_sock *nlk = nlk_sk(sk);
1058 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1060 if (alen < sizeof(addr->sa_family))
1063 if (addr->sa_family == AF_UNSPEC) {
1064 sk->sk_state = NETLINK_UNCONNECTED;
1065 nlk->dst_portid = 0;
1069 if (addr->sa_family != AF_NETLINK)
1072 if (alen < sizeof(struct sockaddr_nl))
1075 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1076 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1079 /* No need for barriers here as we return to user-space without
1080 * using any of the bound attributes.
1081 * Paired with WRITE_ONCE() in netlink_insert().
1083 if (!READ_ONCE(nlk->bound))
1084 err = netlink_autobind(sock);
1087 sk->sk_state = NETLINK_CONNECTED;
1088 nlk->dst_portid = nladdr->nl_pid;
1089 nlk->dst_group = ffs(nladdr->nl_groups);
1095 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1096 int *addr_len, int peer)
1098 struct sock *sk = sock->sk;
1099 struct netlink_sock *nlk = nlk_sk(sk);
1100 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1102 nladdr->nl_family = AF_NETLINK;
1104 *addr_len = sizeof(*nladdr);
1107 nladdr->nl_pid = nlk->dst_portid;
1108 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1110 nladdr->nl_pid = nlk->portid;
1111 netlink_lock_table();
1112 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1113 netlink_unlock_table();
1118 static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1121 /* try to hand this ioctl down to the NIC drivers.
1123 return -ENOIOCTLCMD;
1126 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1129 struct netlink_sock *nlk;
1131 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1133 return ERR_PTR(-ECONNREFUSED);
1135 /* Don't bother queuing skb if kernel socket has no input function */
1137 if (sock->sk_state == NETLINK_CONNECTED &&
1138 nlk->dst_portid != nlk_sk(ssk)->portid) {
1140 return ERR_PTR(-ECONNREFUSED);
1145 struct sock *netlink_getsockbyfilp(struct file *filp)
1147 struct inode *inode = file_inode(filp);
1150 if (!S_ISSOCK(inode->i_mode))
1151 return ERR_PTR(-ENOTSOCK);
1153 sock = SOCKET_I(inode)->sk;
1154 if (sock->sk_family != AF_NETLINK)
1155 return ERR_PTR(-EINVAL);
1161 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1164 struct sk_buff *skb;
1167 if (size <= NLMSG_GOODSIZE || broadcast)
1168 return alloc_skb(size, GFP_KERNEL);
1170 size = SKB_DATA_ALIGN(size) +
1171 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1173 data = vmalloc(size);
1177 skb = __build_skb(data, size);
1181 skb->destructor = netlink_skb_destructor;
1187 * Attach a skb to a netlink socket.
1188 * The caller must hold a reference to the destination socket. On error, the
1189 * reference is dropped. The skb is not send to the destination, just all
1190 * all error checks are performed and memory in the queue is reserved.
1192 * < 0: error. skb freed, reference to sock dropped.
1194 * 1: repeat lookup - reference dropped while waiting for socket memory.
1196 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1197 long *timeo, struct sock *ssk)
1199 struct netlink_sock *nlk;
1203 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1204 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1205 DECLARE_WAITQUEUE(wait, current);
1207 if (!ssk || netlink_is_kernel(ssk))
1208 netlink_overrun(sk);
1214 __set_current_state(TASK_INTERRUPTIBLE);
1215 add_wait_queue(&nlk->wait, &wait);
1217 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1218 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1219 !sock_flag(sk, SOCK_DEAD))
1220 *timeo = schedule_timeout(*timeo);
1222 __set_current_state(TASK_RUNNING);
1223 remove_wait_queue(&nlk->wait, &wait);
1226 if (signal_pending(current)) {
1228 return sock_intr_errno(*timeo);
1232 netlink_skb_set_owner_r(skb, sk);
1236 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1240 netlink_deliver_tap(skb);
1242 skb_queue_tail(&sk->sk_receive_queue, skb);
1243 sk->sk_data_ready(sk);
1247 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1249 int len = __netlink_sendskb(sk, skb);
1255 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1261 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1265 WARN_ON(skb->sk != NULL);
1266 delta = skb->end - skb->tail;
1267 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1270 if (skb_shared(skb)) {
1271 struct sk_buff *nskb = skb_clone(skb, allocation);
1278 pskb_expand_head(skb, 0, -delta,
1279 (allocation & ~__GFP_DIRECT_RECLAIM) |
1280 __GFP_NOWARN | __GFP_NORETRY);
1284 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1288 struct netlink_sock *nlk = nlk_sk(sk);
1290 ret = -ECONNREFUSED;
1291 if (nlk->netlink_rcv != NULL) {
1293 netlink_skb_set_owner_r(skb, sk);
1294 NETLINK_CB(skb).sk = ssk;
1295 netlink_deliver_tap_kernel(sk, ssk, skb);
1296 nlk->netlink_rcv(skb);
1305 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1306 u32 portid, int nonblock)
1312 skb = netlink_trim(skb, gfp_any());
1314 timeo = sock_sndtimeo(ssk, nonblock);
1316 sk = netlink_getsockbyportid(ssk, portid);
1321 if (netlink_is_kernel(sk))
1322 return netlink_unicast_kernel(sk, skb, ssk);
1324 if (sk_filter(sk, skb)) {
1331 err = netlink_attachskb(sk, skb, &timeo, ssk);
1337 return netlink_sendskb(sk, skb);
1339 EXPORT_SYMBOL(netlink_unicast);
1341 int netlink_has_listeners(struct sock *sk, unsigned int group)
1344 struct listeners *listeners;
1346 BUG_ON(!netlink_is_kernel(sk));
1349 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1351 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1352 res = test_bit(group - 1, listeners->masks);
1358 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1360 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1362 struct netlink_sock *nlk = nlk_sk(sk);
1364 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1365 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1366 netlink_skb_set_owner_r(skb, sk);
1367 __netlink_sendskb(sk, skb);
1368 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1373 struct netlink_broadcast_data {
1374 struct sock *exclude_sk;
1379 int delivery_failure;
1383 struct sk_buff *skb, *skb2;
1384 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1388 static void do_one_broadcast(struct sock *sk,
1389 struct netlink_broadcast_data *p)
1391 struct netlink_sock *nlk = nlk_sk(sk);
1394 if (p->exclude_sk == sk)
1397 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1398 !test_bit(p->group - 1, nlk->groups))
1401 if (!net_eq(sock_net(sk), p->net)) {
1402 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1405 if (!peernet_has_id(sock_net(sk), p->net))
1408 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1414 netlink_overrun(sk);
1419 if (p->skb2 == NULL) {
1420 if (skb_shared(p->skb)) {
1421 p->skb2 = skb_clone(p->skb, p->allocation);
1423 p->skb2 = skb_get(p->skb);
1425 * skb ownership may have been set when
1426 * delivered to a previous socket.
1428 skb_orphan(p->skb2);
1431 if (p->skb2 == NULL) {
1432 netlink_overrun(sk);
1433 /* Clone failed. Notify ALL listeners. */
1435 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1436 p->delivery_failure = 1;
1439 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1444 if (sk_filter(sk, p->skb2)) {
1449 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1450 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1451 NETLINK_CB(p->skb2).nsid_is_set = true;
1452 val = netlink_broadcast_deliver(sk, p->skb2);
1454 netlink_overrun(sk);
1455 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1456 p->delivery_failure = 1;
1458 p->congested |= val;
1466 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1467 u32 group, gfp_t allocation,
1468 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1471 struct net *net = sock_net(ssk);
1472 struct netlink_broadcast_data info;
1475 skb = netlink_trim(skb, allocation);
1477 info.exclude_sk = ssk;
1479 info.portid = portid;
1482 info.delivery_failure = 0;
1485 info.allocation = allocation;
1488 info.tx_filter = filter;
1489 info.tx_data = filter_data;
1491 /* While we sleep in clone, do not allow to change socket list */
1493 netlink_lock_table();
1495 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1496 do_one_broadcast(sk, &info);
1500 netlink_unlock_table();
1502 if (info.delivery_failure) {
1503 kfree_skb(info.skb2);
1506 consume_skb(info.skb2);
1508 if (info.delivered) {
1509 if (info.congested && gfpflags_allow_blocking(allocation))
1515 EXPORT_SYMBOL(netlink_broadcast_filtered);
1517 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1518 u32 group, gfp_t allocation)
1520 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1523 EXPORT_SYMBOL(netlink_broadcast);
1525 struct netlink_set_err_data {
1526 struct sock *exclude_sk;
1532 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1534 struct netlink_sock *nlk = nlk_sk(sk);
1537 if (sk == p->exclude_sk)
1540 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1543 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1544 !test_bit(p->group - 1, nlk->groups))
1547 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1552 sk->sk_err = p->code;
1553 sk->sk_error_report(sk);
1559 * netlink_set_err - report error to broadcast listeners
1560 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1561 * @portid: the PORTID of a process that we want to skip (if any)
1562 * @group: the broadcast group that will notice the error
1563 * @code: error code, must be negative (as usual in kernelspace)
1565 * This function returns the number of broadcast listeners that have set the
1566 * NETLINK_NO_ENOBUFS socket option.
1568 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1570 struct netlink_set_err_data info;
1574 info.exclude_sk = ssk;
1575 info.portid = portid;
1577 /* sk->sk_err wants a positive error value */
1580 read_lock(&nl_table_lock);
1582 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1583 ret += do_one_set_err(sk, &info);
1585 read_unlock(&nl_table_lock);
1588 EXPORT_SYMBOL(netlink_set_err);
1590 /* must be called with netlink table grabbed */
1591 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1595 int old, new = !!is_new, subscriptions;
1597 old = test_bit(group - 1, nlk->groups);
1598 subscriptions = nlk->subscriptions - old + new;
1600 __set_bit(group - 1, nlk->groups);
1602 __clear_bit(group - 1, nlk->groups);
1603 netlink_update_subscriptions(&nlk->sk, subscriptions);
1604 netlink_update_listeners(&nlk->sk);
1607 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1608 char __user *optval, unsigned int optlen)
1610 struct sock *sk = sock->sk;
1611 struct netlink_sock *nlk = nlk_sk(sk);
1612 unsigned int val = 0;
1615 if (level != SOL_NETLINK)
1616 return -ENOPROTOOPT;
1618 if (optlen >= sizeof(int) &&
1619 get_user(val, (unsigned int __user *)optval))
1623 case NETLINK_PKTINFO:
1625 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1627 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1630 case NETLINK_ADD_MEMBERSHIP:
1631 case NETLINK_DROP_MEMBERSHIP: {
1632 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1634 err = netlink_realloc_groups(sk);
1637 if (!val || val - 1 >= nlk->ngroups)
1639 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1640 err = nlk->netlink_bind(sock_net(sk), val);
1644 netlink_table_grab();
1645 netlink_update_socket_mc(nlk, val,
1646 optname == NETLINK_ADD_MEMBERSHIP);
1647 netlink_table_ungrab();
1648 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1649 nlk->netlink_unbind(sock_net(sk), val);
1654 case NETLINK_BROADCAST_ERROR:
1656 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1658 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1661 case NETLINK_NO_ENOBUFS:
1663 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1664 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1665 wake_up_interruptible(&nlk->wait);
1667 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1671 case NETLINK_LISTEN_ALL_NSID:
1672 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1676 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1678 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1681 case NETLINK_CAP_ACK:
1683 nlk->flags |= NETLINK_F_CAP_ACK;
1685 nlk->flags &= ~NETLINK_F_CAP_ACK;
1688 case NETLINK_EXT_ACK:
1690 nlk->flags |= NETLINK_F_EXT_ACK;
1692 nlk->flags &= ~NETLINK_F_EXT_ACK;
1701 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1702 char __user *optval, int __user *optlen)
1704 struct sock *sk = sock->sk;
1705 struct netlink_sock *nlk = nlk_sk(sk);
1708 if (level != SOL_NETLINK)
1709 return -ENOPROTOOPT;
1711 if (get_user(len, optlen))
1717 case NETLINK_PKTINFO:
1718 if (len < sizeof(int))
1721 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1722 if (put_user(len, optlen) ||
1723 put_user(val, optval))
1727 case NETLINK_BROADCAST_ERROR:
1728 if (len < sizeof(int))
1731 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1732 if (put_user(len, optlen) ||
1733 put_user(val, optval))
1737 case NETLINK_NO_ENOBUFS:
1738 if (len < sizeof(int))
1741 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1742 if (put_user(len, optlen) ||
1743 put_user(val, optval))
1747 case NETLINK_LIST_MEMBERSHIPS: {
1748 int pos, idx, shift;
1751 netlink_lock_table();
1752 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1753 if (len - pos < sizeof(u32))
1756 idx = pos / sizeof(unsigned long);
1757 shift = (pos % sizeof(unsigned long)) * 8;
1758 if (put_user((u32)(nlk->groups[idx] >> shift),
1759 (u32 __user *)(optval + pos))) {
1764 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1766 netlink_unlock_table();
1769 case NETLINK_CAP_ACK:
1770 if (len < sizeof(int))
1773 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1774 if (put_user(len, optlen) ||
1775 put_user(val, optval))
1779 case NETLINK_EXT_ACK:
1780 if (len < sizeof(int))
1783 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1784 if (put_user(len, optlen) || put_user(val, optval))
1794 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1796 struct nl_pktinfo info;
1798 info.group = NETLINK_CB(skb).dst_group;
1799 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1802 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1803 struct sk_buff *skb)
1805 if (!NETLINK_CB(skb).nsid_is_set)
1808 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1809 &NETLINK_CB(skb).nsid);
1812 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1814 struct sock *sk = sock->sk;
1815 struct netlink_sock *nlk = nlk_sk(sk);
1816 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1819 struct sk_buff *skb;
1821 struct scm_cookie scm;
1822 u32 netlink_skb_flags = 0;
1824 if (msg->msg_flags&MSG_OOB)
1828 pr_warn_once("Zero length message leads to an empty skb\n");
1832 err = scm_send(sock, msg, &scm, true);
1836 if (msg->msg_namelen) {
1838 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1840 if (addr->nl_family != AF_NETLINK)
1842 dst_portid = addr->nl_pid;
1843 dst_group = ffs(addr->nl_groups);
1845 if ((dst_group || dst_portid) &&
1846 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1848 netlink_skb_flags |= NETLINK_SKB_DST;
1850 dst_portid = nlk->dst_portid;
1851 dst_group = nlk->dst_group;
1854 /* Paired with WRITE_ONCE() in netlink_insert() */
1855 if (!READ_ONCE(nlk->bound)) {
1856 err = netlink_autobind(sock);
1860 /* Ensure nlk is hashed and visible. */
1865 if (len > sk->sk_sndbuf - 32)
1868 skb = netlink_alloc_large_skb(len, dst_group);
1872 NETLINK_CB(skb).portid = nlk->portid;
1873 NETLINK_CB(skb).dst_group = dst_group;
1874 NETLINK_CB(skb).creds = scm.creds;
1875 NETLINK_CB(skb).flags = netlink_skb_flags;
1878 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1883 err = security_netlink_send(sk, skb);
1890 refcount_inc(&skb->users);
1891 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1893 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1900 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1903 struct scm_cookie scm;
1904 struct sock *sk = sock->sk;
1905 struct netlink_sock *nlk = nlk_sk(sk);
1906 int noblock = flags&MSG_DONTWAIT;
1908 struct sk_buff *skb, *data_skb;
1916 skb = skb_recv_datagram(sk, flags, noblock, &err);
1922 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1923 if (unlikely(skb_shinfo(skb)->frag_list)) {
1925 * If this skb has a frag_list, then here that means that we
1926 * will have to use the frag_list skb's data for compat tasks
1927 * and the regular skb's data for normal (non-compat) tasks.
1929 * If we need to send the compat skb, assign it to the
1930 * 'data_skb' variable so that it will be used below for data
1931 * copying. We keep 'skb' for everything else, including
1932 * freeing both later.
1934 if (flags & MSG_CMSG_COMPAT)
1935 data_skb = skb_shinfo(skb)->frag_list;
1939 /* Record the max length of recvmsg() calls for future allocations */
1940 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1941 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1942 SKB_WITH_OVERHEAD(32768));
1944 copied = data_skb->len;
1946 msg->msg_flags |= MSG_TRUNC;
1950 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1952 if (msg->msg_name) {
1953 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1954 addr->nl_family = AF_NETLINK;
1956 addr->nl_pid = NETLINK_CB(skb).portid;
1957 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1958 msg->msg_namelen = sizeof(*addr);
1961 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1962 netlink_cmsg_recv_pktinfo(msg, skb);
1963 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1964 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1966 memset(&scm, 0, sizeof(scm));
1967 scm.creds = *NETLINK_CREDS(skb);
1968 if (flags & MSG_TRUNC)
1969 copied = data_skb->len;
1971 skb_free_datagram(sk, skb);
1973 if (nlk->cb_running &&
1974 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1975 ret = netlink_dump(sk);
1978 sk->sk_error_report(sk);
1982 scm_recv(sock, msg, &scm, flags);
1984 netlink_rcv_wake(sk);
1985 return err ? : copied;
1988 static void netlink_data_ready(struct sock *sk)
1994 * We export these functions to other modules. They provide a
1995 * complete set of kernel non-blocking support for message
2000 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2001 struct netlink_kernel_cfg *cfg)
2003 struct socket *sock;
2005 struct netlink_sock *nlk;
2006 struct listeners *listeners = NULL;
2007 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2008 unsigned int groups;
2012 if (unit < 0 || unit >= MAX_LINKS)
2015 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2018 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2019 goto out_sock_release_nosk;
2023 if (!cfg || cfg->groups < 32)
2026 groups = cfg->groups;
2028 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2030 goto out_sock_release;
2032 sk->sk_data_ready = netlink_data_ready;
2033 if (cfg && cfg->input)
2034 nlk_sk(sk)->netlink_rcv = cfg->input;
2036 if (netlink_insert(sk, 0))
2037 goto out_sock_release;
2040 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2042 netlink_table_grab();
2043 if (!nl_table[unit].registered) {
2044 nl_table[unit].groups = groups;
2045 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2046 nl_table[unit].cb_mutex = cb_mutex;
2047 nl_table[unit].module = module;
2049 nl_table[unit].bind = cfg->bind;
2050 nl_table[unit].unbind = cfg->unbind;
2051 nl_table[unit].flags = cfg->flags;
2053 nl_table[unit].compare = cfg->compare;
2055 nl_table[unit].registered = 1;
2058 nl_table[unit].registered++;
2060 netlink_table_ungrab();
2065 netlink_kernel_release(sk);
2068 out_sock_release_nosk:
2072 EXPORT_SYMBOL(__netlink_kernel_create);
2075 netlink_kernel_release(struct sock *sk)
2077 if (sk == NULL || sk->sk_socket == NULL)
2080 sock_release(sk->sk_socket);
2082 EXPORT_SYMBOL(netlink_kernel_release);
2084 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2086 struct listeners *new, *old;
2087 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2092 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2093 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2096 old = nl_deref_protected(tbl->listeners);
2097 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2098 rcu_assign_pointer(tbl->listeners, new);
2100 kfree_rcu(old, rcu);
2102 tbl->groups = groups;
2108 * netlink_change_ngroups - change number of multicast groups
2110 * This changes the number of multicast groups that are available
2111 * on a certain netlink family. Note that it is not possible to
2112 * change the number of groups to below 32. Also note that it does
2113 * not implicitly call netlink_clear_multicast_users() when the
2114 * number of groups is reduced.
2116 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2117 * @groups: The new number of groups.
2119 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2123 netlink_table_grab();
2124 err = __netlink_change_ngroups(sk, groups);
2125 netlink_table_ungrab();
2130 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2133 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2135 sk_for_each_bound(sk, &tbl->mc_list)
2136 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2140 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2142 struct nlmsghdr *nlh;
2143 int size = nlmsg_msg_size(len);
2145 nlh = skb_put(skb, NLMSG_ALIGN(size));
2146 nlh->nlmsg_type = type;
2147 nlh->nlmsg_len = size;
2148 nlh->nlmsg_flags = flags;
2149 nlh->nlmsg_pid = portid;
2150 nlh->nlmsg_seq = seq;
2151 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2152 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2155 EXPORT_SYMBOL(__nlmsg_put);
2158 * It looks a bit ugly.
2159 * It would be better to create kernel thread.
2162 static int netlink_dump(struct sock *sk)
2164 struct netlink_sock *nlk = nlk_sk(sk);
2165 struct netlink_callback *cb;
2166 struct sk_buff *skb = NULL;
2167 struct nlmsghdr *nlh;
2168 struct module *module;
2173 mutex_lock(nlk->cb_mutex);
2174 if (!nlk->cb_running) {
2179 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2182 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2183 * required, but it makes sense to _attempt_ a 16K bytes allocation
2184 * to reduce number of system calls on dump operations, if user
2185 * ever provided a big enough buffer.
2188 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2190 if (alloc_min_size < nlk->max_recvmsg_len) {
2191 alloc_size = nlk->max_recvmsg_len;
2192 skb = alloc_skb(alloc_size,
2193 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2194 __GFP_NOWARN | __GFP_NORETRY);
2197 alloc_size = alloc_min_size;
2198 skb = alloc_skb(alloc_size, GFP_KERNEL);
2203 /* Trim skb to allocated size. User is expected to provide buffer as
2204 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2205 * netlink_recvmsg())). dump will pack as many smaller messages as
2206 * could fit within the allocated skb. skb is typically allocated
2207 * with larger space than required (could be as much as near 2x the
2208 * requested size with align to next power of 2 approach). Allowing
2209 * dump to use the excess space makes it difficult for a user to have a
2210 * reasonable static buffer based on the expected largest dump of a
2211 * single netdev. The outcome is MSG_TRUNC error.
2213 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2215 /* Make sure malicious BPF programs can not read unitialized memory
2216 * from skb->head -> skb->data
2218 skb_reset_network_header(skb);
2219 skb_reset_mac_header(skb);
2221 netlink_skb_set_owner_r(skb, sk);
2223 if (nlk->dump_done_errno > 0)
2224 nlk->dump_done_errno = cb->dump(skb, cb);
2226 if (nlk->dump_done_errno > 0 ||
2227 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2228 mutex_unlock(nlk->cb_mutex);
2230 if (sk_filter(sk, skb))
2233 __netlink_sendskb(sk, skb);
2237 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
2238 sizeof(nlk->dump_done_errno), NLM_F_MULTI);
2242 nl_dump_check_consistent(cb, nlh);
2244 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
2245 sizeof(nlk->dump_done_errno));
2247 if (sk_filter(sk, skb))
2250 __netlink_sendskb(sk, skb);
2255 nlk->cb_running = false;
2256 module = cb->module;
2258 mutex_unlock(nlk->cb_mutex);
2264 mutex_unlock(nlk->cb_mutex);
2269 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2270 const struct nlmsghdr *nlh,
2271 struct netlink_dump_control *control)
2273 struct netlink_callback *cb;
2275 struct netlink_sock *nlk;
2278 refcount_inc(&skb->users);
2280 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2282 ret = -ECONNREFUSED;
2287 mutex_lock(nlk->cb_mutex);
2288 /* A dump is in progress... */
2289 if (nlk->cb_running) {
2293 /* add reference of module which cb->dump belongs to */
2294 if (!try_module_get(control->module)) {
2295 ret = -EPROTONOSUPPORT;
2300 memset(cb, 0, sizeof(*cb));
2301 cb->start = control->start;
2302 cb->dump = control->dump;
2303 cb->done = control->done;
2305 cb->data = control->data;
2306 cb->module = control->module;
2307 cb->min_dump_alloc = control->min_dump_alloc;
2311 ret = cb->start(cb);
2316 nlk->cb_running = true;
2317 nlk->dump_done_errno = INT_MAX;
2319 mutex_unlock(nlk->cb_mutex);
2321 ret = netlink_dump(sk);
2328 /* We successfully started a dump, by returning -EINTR we
2329 * signal not to send ACK even if it was requested.
2334 module_put(control->module);
2337 mutex_unlock(nlk->cb_mutex);
2342 EXPORT_SYMBOL(__netlink_dump_start);
2344 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2345 const struct netlink_ext_ack *extack)
2347 struct sk_buff *skb;
2348 struct nlmsghdr *rep;
2349 struct nlmsgerr *errmsg;
2350 size_t payload = sizeof(*errmsg);
2352 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2353 unsigned int flags = 0;
2354 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK;
2356 /* Error messages get the original request appened, unless the user
2357 * requests to cap the error message, and get extra error data if
2361 if (!(nlk->flags & NETLINK_F_CAP_ACK))
2362 payload += nlmsg_len(nlh);
2364 flags |= NLM_F_CAPPED;
2365 if (nlk_has_extack && extack) {
2367 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2368 if (extack->bad_attr)
2369 tlvlen += nla_total_size(sizeof(u32));
2372 flags |= NLM_F_CAPPED;
2374 if (nlk_has_extack && extack && extack->cookie_len)
2375 tlvlen += nla_total_size(extack->cookie_len);
2379 flags |= NLM_F_ACK_TLVS;
2381 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2385 sk = netlink_lookup(sock_net(in_skb->sk),
2386 in_skb->sk->sk_protocol,
2387 NETLINK_CB(in_skb).portid);
2389 sk->sk_err = ENOBUFS;
2390 sk->sk_error_report(sk);
2396 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2397 NLMSG_ERROR, payload, flags);
2398 errmsg = nlmsg_data(rep);
2399 errmsg->error = err;
2400 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2402 if (nlk_has_extack && extack) {
2405 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2407 if (extack->bad_attr &&
2408 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2409 (u8 *)extack->bad_attr >= in_skb->data +
2411 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2412 (u8 *)extack->bad_attr -
2415 if (extack->cookie_len)
2416 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2422 nlmsg_end(skb, rep);
2424 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2426 EXPORT_SYMBOL(netlink_ack);
2428 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2430 struct netlink_ext_ack *))
2432 struct netlink_ext_ack extack;
2433 struct nlmsghdr *nlh;
2436 while (skb->len >= nlmsg_total_size(0)) {
2439 memset(&extack, 0, sizeof(extack));
2440 nlh = nlmsg_hdr(skb);
2443 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2446 /* Only requests are handled by the kernel */
2447 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2450 /* Skip control messages */
2451 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2454 err = cb(skb, nlh, &extack);
2459 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2460 netlink_ack(skb, nlh, err, &extack);
2463 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2464 if (msglen > skb->len)
2466 skb_pull(skb, msglen);
2471 EXPORT_SYMBOL(netlink_rcv_skb);
2474 * nlmsg_notify - send a notification netlink message
2475 * @sk: netlink socket to use
2476 * @skb: notification message
2477 * @portid: destination netlink portid for reports or 0
2478 * @group: destination multicast group or 0
2479 * @report: 1 to report back, 0 to disable
2480 * @flags: allocation flags
2482 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2483 unsigned int group, int report, gfp_t flags)
2488 int exclude_portid = 0;
2491 refcount_inc(&skb->users);
2492 exclude_portid = portid;
2495 /* errors reported via destination sk->sk_err, but propagate
2496 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2497 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2505 err2 = nlmsg_unicast(sk, skb, portid);
2512 EXPORT_SYMBOL(nlmsg_notify);
2514 #ifdef CONFIG_PROC_FS
2515 struct nl_seq_iter {
2516 struct seq_net_private p;
2517 struct rhashtable_iter hti;
2521 static int netlink_walk_start(struct nl_seq_iter *iter)
2525 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
2528 iter->link = MAX_LINKS;
2532 err = rhashtable_walk_start(&iter->hti);
2533 return err == -EAGAIN ? 0 : err;
2536 static void netlink_walk_stop(struct nl_seq_iter *iter)
2538 rhashtable_walk_stop(&iter->hti);
2539 rhashtable_walk_exit(&iter->hti);
2542 static void *__netlink_seq_next(struct seq_file *seq)
2544 struct nl_seq_iter *iter = seq->private;
2545 struct netlink_sock *nlk;
2551 nlk = rhashtable_walk_next(&iter->hti);
2554 if (PTR_ERR(nlk) == -EAGAIN)
2563 netlink_walk_stop(iter);
2564 if (++iter->link >= MAX_LINKS)
2567 err = netlink_walk_start(iter);
2569 return ERR_PTR(err);
2571 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2576 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2578 struct nl_seq_iter *iter = seq->private;
2579 void *obj = SEQ_START_TOKEN;
2585 err = netlink_walk_start(iter);
2587 return ERR_PTR(err);
2589 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2590 obj = __netlink_seq_next(seq);
2595 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2598 return __netlink_seq_next(seq);
2601 static void netlink_seq_stop(struct seq_file *seq, void *v)
2603 struct nl_seq_iter *iter = seq->private;
2605 if (iter->link >= MAX_LINKS)
2608 netlink_walk_stop(iter);
2612 static int netlink_seq_show(struct seq_file *seq, void *v)
2614 if (v == SEQ_START_TOKEN) {
2616 "sk Eth Pid Groups "
2617 "Rmem Wmem Dump Locks Drops Inode\n");
2620 struct netlink_sock *nlk = nlk_sk(s);
2622 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2626 nlk->groups ? (u32)nlk->groups[0] : 0,
2627 sk_rmem_alloc_get(s),
2628 sk_wmem_alloc_get(s),
2630 refcount_read(&s->sk_refcnt),
2631 atomic_read(&s->sk_drops),
2639 static const struct seq_operations netlink_seq_ops = {
2640 .start = netlink_seq_start,
2641 .next = netlink_seq_next,
2642 .stop = netlink_seq_stop,
2643 .show = netlink_seq_show,
2647 static int netlink_seq_open(struct inode *inode, struct file *file)
2649 return seq_open_net(inode, file, &netlink_seq_ops,
2650 sizeof(struct nl_seq_iter));
2653 static const struct file_operations netlink_seq_fops = {
2654 .owner = THIS_MODULE,
2655 .open = netlink_seq_open,
2657 .llseek = seq_lseek,
2658 .release = seq_release_net,
2663 int netlink_register_notifier(struct notifier_block *nb)
2665 return blocking_notifier_chain_register(&netlink_chain, nb);
2667 EXPORT_SYMBOL(netlink_register_notifier);
2669 int netlink_unregister_notifier(struct notifier_block *nb)
2671 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2673 EXPORT_SYMBOL(netlink_unregister_notifier);
2675 static const struct proto_ops netlink_ops = {
2676 .family = PF_NETLINK,
2677 .owner = THIS_MODULE,
2678 .release = netlink_release,
2679 .bind = netlink_bind,
2680 .connect = netlink_connect,
2681 .socketpair = sock_no_socketpair,
2682 .accept = sock_no_accept,
2683 .getname = netlink_getname,
2684 .poll = datagram_poll,
2685 .ioctl = netlink_ioctl,
2686 .listen = sock_no_listen,
2687 .shutdown = sock_no_shutdown,
2688 .setsockopt = netlink_setsockopt,
2689 .getsockopt = netlink_getsockopt,
2690 .sendmsg = netlink_sendmsg,
2691 .recvmsg = netlink_recvmsg,
2692 .mmap = sock_no_mmap,
2693 .sendpage = sock_no_sendpage,
2696 static const struct net_proto_family netlink_family_ops = {
2697 .family = PF_NETLINK,
2698 .create = netlink_create,
2699 .owner = THIS_MODULE, /* for consistency 8) */
2702 static int __net_init netlink_net_init(struct net *net)
2704 #ifdef CONFIG_PROC_FS
2705 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2711 static void __net_exit netlink_net_exit(struct net *net)
2713 #ifdef CONFIG_PROC_FS
2714 remove_proc_entry("netlink", net->proc_net);
2718 static void __init netlink_add_usersock_entry(void)
2720 struct listeners *listeners;
2723 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2725 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2727 netlink_table_grab();
2729 nl_table[NETLINK_USERSOCK].groups = groups;
2730 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2731 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2732 nl_table[NETLINK_USERSOCK].registered = 1;
2733 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2735 netlink_table_ungrab();
2738 static struct pernet_operations __net_initdata netlink_net_ops = {
2739 .init = netlink_net_init,
2740 .exit = netlink_net_exit,
2743 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2745 const struct netlink_sock *nlk = data;
2746 struct netlink_compare_arg arg;
2748 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2749 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2752 static const struct rhashtable_params netlink_rhashtable_params = {
2753 .head_offset = offsetof(struct netlink_sock, node),
2754 .key_len = netlink_compare_arg_len,
2755 .obj_hashfn = netlink_hash,
2756 .obj_cmpfn = netlink_compare,
2757 .automatic_shrinking = true,
2760 static int __init netlink_proto_init(void)
2763 int err = proto_register(&netlink_proto, 0);
2768 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2770 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2774 for (i = 0; i < MAX_LINKS; i++) {
2775 if (rhashtable_init(&nl_table[i].hash,
2776 &netlink_rhashtable_params) < 0) {
2778 rhashtable_destroy(&nl_table[i].hash);
2784 INIT_LIST_HEAD(&netlink_tap_all);
2786 netlink_add_usersock_entry();
2788 sock_register(&netlink_family_ops);
2789 register_pernet_subsys(&netlink_net_ops);
2790 /* The netlink device handler may be needed early. */
2795 panic("netlink_init: Cannot allocate nl_table\n");
2798 core_initcall(netlink_proto_init);