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>
67 #include <net/net_namespace.h>
68 #include <net/netns/generic.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);
133 /* nl_table locking explained:
134 * Lookup and traversal are protected with an RCU read-side lock. Insertion
135 * and removal are protected with per bucket lock while using RCU list
136 * modification primitives and may run in parallel to RCU protected lookups.
137 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
138 * been acquired * either during or after the socket has been removed from
139 * the list and after an RCU grace period.
141 DEFINE_RWLOCK(nl_table_lock);
142 EXPORT_SYMBOL_GPL(nl_table_lock);
143 static atomic_t nl_table_users = ATOMIC_INIT(0);
145 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
147 static BLOCKING_NOTIFIER_HEAD(netlink_chain);
150 static const struct rhashtable_params netlink_rhashtable_params;
152 static inline u32 netlink_group_mask(u32 group)
154 return group ? 1 << (group - 1) : 0;
157 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
160 unsigned int len = skb_end_offset(skb);
163 new = alloc_skb(len, gfp_mask);
167 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
168 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
169 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
171 skb_put_data(new, skb->data, len);
175 static unsigned int netlink_tap_net_id;
177 struct netlink_tap_net {
178 struct list_head netlink_tap_all;
179 struct mutex netlink_tap_lock;
182 int netlink_add_tap(struct netlink_tap *nt)
184 struct net *net = dev_net(nt->dev);
185 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
187 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
190 mutex_lock(&nn->netlink_tap_lock);
191 list_add_rcu(&nt->list, &nn->netlink_tap_all);
192 mutex_unlock(&nn->netlink_tap_lock);
194 __module_get(nt->module);
198 EXPORT_SYMBOL_GPL(netlink_add_tap);
200 static int __netlink_remove_tap(struct netlink_tap *nt)
202 struct net *net = dev_net(nt->dev);
203 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
205 struct netlink_tap *tmp;
207 mutex_lock(&nn->netlink_tap_lock);
209 list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
211 list_del_rcu(&nt->list);
217 pr_warn("__netlink_remove_tap: %p not found\n", nt);
219 mutex_unlock(&nn->netlink_tap_lock);
222 module_put(nt->module);
224 return found ? 0 : -ENODEV;
227 int netlink_remove_tap(struct netlink_tap *nt)
231 ret = __netlink_remove_tap(nt);
236 EXPORT_SYMBOL_GPL(netlink_remove_tap);
238 static __net_init int netlink_tap_init_net(struct net *net)
240 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
242 INIT_LIST_HEAD(&nn->netlink_tap_all);
243 mutex_init(&nn->netlink_tap_lock);
247 static void __net_exit netlink_tap_exit_net(struct net *net)
251 static struct pernet_operations netlink_tap_net_ops = {
252 .init = netlink_tap_init_net,
253 .exit = netlink_tap_exit_net,
254 .id = &netlink_tap_net_id,
255 .size = sizeof(struct netlink_tap_net),
258 static bool netlink_filter_tap(const struct sk_buff *skb)
260 struct sock *sk = skb->sk;
262 /* We take the more conservative approach and
263 * whitelist socket protocols that may pass.
265 switch (sk->sk_protocol) {
267 case NETLINK_USERSOCK:
268 case NETLINK_SOCK_DIAG:
271 case NETLINK_FIB_LOOKUP:
272 case NETLINK_NETFILTER:
273 case NETLINK_GENERIC:
280 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
281 struct net_device *dev)
283 struct sk_buff *nskb;
284 struct sock *sk = skb->sk;
287 if (!net_eq(dev_net(dev), sock_net(sk)))
292 if (is_vmalloc_addr(skb->head))
293 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
295 nskb = skb_clone(skb, GFP_ATOMIC);
298 nskb->protocol = htons((u16) sk->sk_protocol);
299 nskb->pkt_type = netlink_is_kernel(sk) ?
300 PACKET_KERNEL : PACKET_USER;
301 skb_reset_network_header(nskb);
302 ret = dev_queue_xmit(nskb);
303 if (unlikely(ret > 0))
304 ret = net_xmit_errno(ret);
311 static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
314 struct netlink_tap *tmp;
316 if (!netlink_filter_tap(skb))
319 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
320 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
326 static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
328 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
332 if (unlikely(!list_empty(&nn->netlink_tap_all)))
333 __netlink_deliver_tap(skb, nn);
338 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
341 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
342 netlink_deliver_tap(sock_net(dst), skb);
345 static void netlink_overrun(struct sock *sk)
347 struct netlink_sock *nlk = nlk_sk(sk);
349 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
350 if (!test_and_set_bit(NETLINK_S_CONGESTED,
351 &nlk_sk(sk)->state)) {
352 sk->sk_err = ENOBUFS;
353 sk->sk_error_report(sk);
356 atomic_inc(&sk->sk_drops);
359 static void netlink_rcv_wake(struct sock *sk)
361 struct netlink_sock *nlk = nlk_sk(sk);
363 if (skb_queue_empty(&sk->sk_receive_queue))
364 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
365 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
366 wake_up_interruptible(&nlk->wait);
369 static void netlink_skb_destructor(struct sk_buff *skb)
371 if (is_vmalloc_addr(skb->head)) {
373 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
382 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
384 WARN_ON(skb->sk != NULL);
386 skb->destructor = netlink_skb_destructor;
387 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
388 sk_mem_charge(sk, skb->truesize);
391 static void netlink_sock_destruct(struct sock *sk)
393 struct netlink_sock *nlk = nlk_sk(sk);
395 if (nlk->cb_running) {
397 nlk->cb.done(&nlk->cb);
398 module_put(nlk->cb.module);
399 kfree_skb(nlk->cb.skb);
402 skb_queue_purge(&sk->sk_receive_queue);
404 if (!sock_flag(sk, SOCK_DEAD)) {
405 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
409 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
410 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
411 WARN_ON(nlk_sk(sk)->groups);
414 static void netlink_sock_destruct_work(struct work_struct *work)
416 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
422 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
423 * SMP. Look, when several writers sleep and reader wakes them up, all but one
424 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
425 * this, _but_ remember, it adds useless work on UP machines.
428 void netlink_table_grab(void)
429 __acquires(nl_table_lock)
433 write_lock_irq(&nl_table_lock);
435 if (atomic_read(&nl_table_users)) {
436 DECLARE_WAITQUEUE(wait, current);
438 add_wait_queue_exclusive(&nl_table_wait, &wait);
440 set_current_state(TASK_UNINTERRUPTIBLE);
441 if (atomic_read(&nl_table_users) == 0)
443 write_unlock_irq(&nl_table_lock);
445 write_lock_irq(&nl_table_lock);
448 __set_current_state(TASK_RUNNING);
449 remove_wait_queue(&nl_table_wait, &wait);
453 void netlink_table_ungrab(void)
454 __releases(nl_table_lock)
456 write_unlock_irq(&nl_table_lock);
457 wake_up(&nl_table_wait);
461 netlink_lock_table(void)
463 /* read_lock() synchronizes us to netlink_table_grab */
465 read_lock(&nl_table_lock);
466 atomic_inc(&nl_table_users);
467 read_unlock(&nl_table_lock);
471 netlink_unlock_table(void)
473 if (atomic_dec_and_test(&nl_table_users))
474 wake_up(&nl_table_wait);
477 struct netlink_compare_arg
483 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
484 #define netlink_compare_arg_len \
485 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
487 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
490 const struct netlink_compare_arg *x = arg->key;
491 const struct netlink_sock *nlk = ptr;
493 return nlk->portid != x->portid ||
494 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
497 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
498 struct net *net, u32 portid)
500 memset(arg, 0, sizeof(*arg));
501 write_pnet(&arg->pnet, net);
502 arg->portid = portid;
505 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
508 struct netlink_compare_arg arg;
510 netlink_compare_arg_init(&arg, net, portid);
511 return rhashtable_lookup_fast(&table->hash, &arg,
512 netlink_rhashtable_params);
515 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
517 struct netlink_compare_arg arg;
519 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
520 return rhashtable_lookup_insert_key(&table->hash, &arg,
522 netlink_rhashtable_params);
525 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
527 struct netlink_table *table = &nl_table[protocol];
531 sk = __netlink_lookup(table, portid, net);
539 static const struct proto_ops netlink_ops;
542 netlink_update_listeners(struct sock *sk)
544 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
547 struct listeners *listeners;
549 listeners = nl_deref_protected(tbl->listeners);
553 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
555 sk_for_each_bound(sk, &tbl->mc_list) {
556 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
557 mask |= nlk_sk(sk)->groups[i];
559 listeners->masks[i] = mask;
561 /* this function is only called with the netlink table "grabbed", which
562 * makes sure updates are visible before bind or setsockopt return. */
565 static int netlink_insert(struct sock *sk, u32 portid)
567 struct netlink_table *table = &nl_table[sk->sk_protocol];
572 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
573 if (nlk_sk(sk)->bound)
577 if (BITS_PER_LONG > 32 &&
578 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
581 nlk_sk(sk)->portid = portid;
584 err = __netlink_insert(table, sk);
586 /* In case the hashtable backend returns with -EBUSY
587 * from here, it must not escape to the caller.
589 if (unlikely(err == -EBUSY))
597 /* We need to ensure that the socket is hashed and visible. */
599 nlk_sk(sk)->bound = portid;
606 static void netlink_remove(struct sock *sk)
608 struct netlink_table *table;
610 table = &nl_table[sk->sk_protocol];
611 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
612 netlink_rhashtable_params)) {
613 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
617 netlink_table_grab();
618 if (nlk_sk(sk)->subscriptions) {
619 __sk_del_bind_node(sk);
620 netlink_update_listeners(sk);
622 if (sk->sk_protocol == NETLINK_GENERIC)
623 atomic_inc(&genl_sk_destructing_cnt);
624 netlink_table_ungrab();
627 static struct proto netlink_proto = {
629 .owner = THIS_MODULE,
630 .obj_size = sizeof(struct netlink_sock),
633 static int __netlink_create(struct net *net, struct socket *sock,
634 struct mutex *cb_mutex, int protocol,
638 struct netlink_sock *nlk;
640 sock->ops = &netlink_ops;
642 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
646 sock_init_data(sock, sk);
650 nlk->cb_mutex = cb_mutex;
652 nlk->cb_mutex = &nlk->cb_def_mutex;
653 mutex_init(nlk->cb_mutex);
654 lockdep_set_class_and_name(nlk->cb_mutex,
655 nlk_cb_mutex_keys + protocol,
656 nlk_cb_mutex_key_strings[protocol]);
658 init_waitqueue_head(&nlk->wait);
660 sk->sk_destruct = netlink_sock_destruct;
661 sk->sk_protocol = protocol;
665 static int netlink_create(struct net *net, struct socket *sock, int protocol,
668 struct module *module = NULL;
669 struct mutex *cb_mutex;
670 struct netlink_sock *nlk;
671 int (*bind)(struct net *net, int group);
672 void (*unbind)(struct net *net, int group);
675 sock->state = SS_UNCONNECTED;
677 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
678 return -ESOCKTNOSUPPORT;
680 if (protocol < 0 || protocol >= MAX_LINKS)
681 return -EPROTONOSUPPORT;
683 netlink_lock_table();
684 #ifdef CONFIG_MODULES
685 if (!nl_table[protocol].registered) {
686 netlink_unlock_table();
687 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
688 netlink_lock_table();
691 if (nl_table[protocol].registered &&
692 try_module_get(nl_table[protocol].module))
693 module = nl_table[protocol].module;
695 err = -EPROTONOSUPPORT;
696 cb_mutex = nl_table[protocol].cb_mutex;
697 bind = nl_table[protocol].bind;
698 unbind = nl_table[protocol].unbind;
699 netlink_unlock_table();
704 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
709 sock_prot_inuse_add(net, &netlink_proto, 1);
712 nlk = nlk_sk(sock->sk);
713 nlk->module = module;
714 nlk->netlink_bind = bind;
715 nlk->netlink_unbind = unbind;
724 static void deferred_put_nlk_sk(struct rcu_head *head)
726 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
727 struct sock *sk = &nlk->sk;
732 if (!refcount_dec_and_test(&sk->sk_refcnt))
735 if (nlk->cb_running && nlk->cb.done) {
736 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
737 schedule_work(&nlk->work);
744 static int netlink_release(struct socket *sock)
746 struct sock *sk = sock->sk;
747 struct netlink_sock *nlk;
757 * OK. Socket is unlinked, any packets that arrive now
761 /* must not acquire netlink_table_lock in any way again before unbind
762 * and notifying genetlink is done as otherwise it might deadlock
764 if (nlk->netlink_unbind) {
767 for (i = 0; i < nlk->ngroups; i++)
768 if (test_bit(i, nlk->groups))
769 nlk->netlink_unbind(sock_net(sk), i + 1);
771 if (sk->sk_protocol == NETLINK_GENERIC &&
772 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
773 wake_up(&genl_sk_destructing_waitq);
776 wake_up_interruptible_all(&nlk->wait);
778 skb_queue_purge(&sk->sk_write_queue);
780 if (nlk->portid && nlk->bound) {
781 struct netlink_notify n = {
783 .protocol = sk->sk_protocol,
784 .portid = nlk->portid,
786 blocking_notifier_call_chain(&netlink_chain,
787 NETLINK_URELEASE, &n);
790 module_put(nlk->module);
792 if (netlink_is_kernel(sk)) {
793 netlink_table_grab();
794 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
795 if (--nl_table[sk->sk_protocol].registered == 0) {
796 struct listeners *old;
798 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
799 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
801 nl_table[sk->sk_protocol].module = NULL;
802 nl_table[sk->sk_protocol].bind = NULL;
803 nl_table[sk->sk_protocol].unbind = NULL;
804 nl_table[sk->sk_protocol].flags = 0;
805 nl_table[sk->sk_protocol].registered = 0;
807 netlink_table_ungrab();
811 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
813 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
817 static int netlink_autobind(struct socket *sock)
819 struct sock *sk = sock->sk;
820 struct net *net = sock_net(sk);
821 struct netlink_table *table = &nl_table[sk->sk_protocol];
822 s32 portid = task_tgid_vnr(current);
830 ok = !__netlink_lookup(table, portid, net);
833 /* Bind collision, search negative portid values. */
835 /* rover will be in range [S32_MIN, -4097] */
836 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
837 else if (rover >= -4096)
843 err = netlink_insert(sk, portid);
844 if (err == -EADDRINUSE)
847 /* If 2 threads race to autobind, that is fine. */
855 * __netlink_ns_capable - General netlink message capability test
856 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
857 * @user_ns: The user namespace of the capability to use
858 * @cap: The capability to use
860 * Test to see if the opener of the socket we received the message
861 * from had when the netlink socket was created and the sender of the
862 * message has has the capability @cap in the user namespace @user_ns.
864 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
865 struct user_namespace *user_ns, int cap)
867 return ((nsp->flags & NETLINK_SKB_DST) ||
868 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
869 ns_capable(user_ns, cap);
871 EXPORT_SYMBOL(__netlink_ns_capable);
874 * netlink_ns_capable - General netlink message capability test
875 * @skb: socket buffer holding a netlink command from userspace
876 * @user_ns: The user namespace of the capability to use
877 * @cap: The capability to use
879 * Test to see if the opener of the socket we received the message
880 * from had when the netlink socket was created and the sender of the
881 * message has has the capability @cap in the user namespace @user_ns.
883 bool netlink_ns_capable(const struct sk_buff *skb,
884 struct user_namespace *user_ns, int cap)
886 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
888 EXPORT_SYMBOL(netlink_ns_capable);
891 * netlink_capable - Netlink global message capability test
892 * @skb: socket buffer holding a netlink command from userspace
893 * @cap: The capability to use
895 * Test to see if the opener of the socket we received the message
896 * from had when the netlink socket was created and the sender of the
897 * message has has the capability @cap in all user namespaces.
899 bool netlink_capable(const struct sk_buff *skb, int cap)
901 return netlink_ns_capable(skb, &init_user_ns, cap);
903 EXPORT_SYMBOL(netlink_capable);
906 * netlink_net_capable - Netlink network namespace message capability test
907 * @skb: socket buffer holding a netlink command from userspace
908 * @cap: The capability to use
910 * Test to see if the opener of the socket we received the message
911 * from had when the netlink socket was created and the sender of the
912 * message has has the capability @cap over the network namespace of
913 * the socket we received the message from.
915 bool netlink_net_capable(const struct sk_buff *skb, int cap)
917 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
919 EXPORT_SYMBOL(netlink_net_capable);
921 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
923 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
924 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
928 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
930 struct netlink_sock *nlk = nlk_sk(sk);
932 if (nlk->subscriptions && !subscriptions)
933 __sk_del_bind_node(sk);
934 else if (!nlk->subscriptions && subscriptions)
935 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
936 nlk->subscriptions = subscriptions;
939 static int netlink_realloc_groups(struct sock *sk)
941 struct netlink_sock *nlk = nlk_sk(sk);
943 unsigned long *new_groups;
946 netlink_table_grab();
948 groups = nl_table[sk->sk_protocol].groups;
949 if (!nl_table[sk->sk_protocol].registered) {
954 if (nlk->ngroups >= groups)
957 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
958 if (new_groups == NULL) {
962 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
963 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
965 nlk->groups = new_groups;
966 nlk->ngroups = groups;
968 netlink_table_ungrab();
972 static void netlink_undo_bind(int group, long unsigned int groups,
975 struct netlink_sock *nlk = nlk_sk(sk);
978 if (!nlk->netlink_unbind)
981 for (undo = 0; undo < group; undo++)
982 if (test_bit(undo, &groups))
983 nlk->netlink_unbind(sock_net(sk), undo + 1);
986 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
989 struct sock *sk = sock->sk;
990 struct net *net = sock_net(sk);
991 struct netlink_sock *nlk = nlk_sk(sk);
992 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
994 long unsigned int groups = nladdr->nl_groups;
997 if (addr_len < sizeof(struct sockaddr_nl))
1000 if (nladdr->nl_family != AF_NETLINK)
1003 /* Only superuser is allowed to listen multicasts */
1005 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1007 err = netlink_realloc_groups(sk);
1014 /* Ensure nlk->portid is up-to-date. */
1017 if (nladdr->nl_pid != nlk->portid)
1021 netlink_lock_table();
1022 if (nlk->netlink_bind && groups) {
1025 for (group = 0; group < nlk->ngroups; group++) {
1026 if (!test_bit(group, &groups))
1028 err = nlk->netlink_bind(net, group + 1);
1031 netlink_undo_bind(group, groups, sk);
1036 /* No need for barriers here as we return to user-space without
1037 * using any of the bound attributes.
1040 err = nladdr->nl_pid ?
1041 netlink_insert(sk, nladdr->nl_pid) :
1042 netlink_autobind(sock);
1044 netlink_undo_bind(nlk->ngroups, groups, sk);
1049 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1051 netlink_unlock_table();
1053 netlink_table_grab();
1054 netlink_update_subscriptions(sk, nlk->subscriptions +
1056 hweight32(nlk->groups[0]));
1057 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1058 netlink_update_listeners(sk);
1059 netlink_table_ungrab();
1064 netlink_unlock_table();
1068 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1069 int alen, int flags)
1072 struct sock *sk = sock->sk;
1073 struct netlink_sock *nlk = nlk_sk(sk);
1074 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1076 if (alen < sizeof(addr->sa_family))
1079 if (addr->sa_family == AF_UNSPEC) {
1080 sk->sk_state = NETLINK_UNCONNECTED;
1081 nlk->dst_portid = 0;
1085 if (addr->sa_family != AF_NETLINK)
1088 if (alen < sizeof(struct sockaddr_nl))
1091 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1092 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1095 /* No need for barriers here as we return to user-space without
1096 * using any of the bound attributes.
1099 err = netlink_autobind(sock);
1102 sk->sk_state = NETLINK_CONNECTED;
1103 nlk->dst_portid = nladdr->nl_pid;
1104 nlk->dst_group = ffs(nladdr->nl_groups);
1110 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1113 struct sock *sk = sock->sk;
1114 struct netlink_sock *nlk = nlk_sk(sk);
1115 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1117 nladdr->nl_family = AF_NETLINK;
1121 nladdr->nl_pid = nlk->dst_portid;
1122 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1124 nladdr->nl_pid = nlk->portid;
1125 netlink_lock_table();
1126 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1127 netlink_unlock_table();
1129 return sizeof(*nladdr);
1132 static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1135 /* try to hand this ioctl down to the NIC drivers.
1137 return -ENOIOCTLCMD;
1140 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1143 struct netlink_sock *nlk;
1145 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1147 return ERR_PTR(-ECONNREFUSED);
1149 /* Don't bother queuing skb if kernel socket has no input function */
1151 if (sock->sk_state == NETLINK_CONNECTED &&
1152 nlk->dst_portid != nlk_sk(ssk)->portid) {
1154 return ERR_PTR(-ECONNREFUSED);
1159 struct sock *netlink_getsockbyfilp(struct file *filp)
1161 struct inode *inode = file_inode(filp);
1164 if (!S_ISSOCK(inode->i_mode))
1165 return ERR_PTR(-ENOTSOCK);
1167 sock = SOCKET_I(inode)->sk;
1168 if (sock->sk_family != AF_NETLINK)
1169 return ERR_PTR(-EINVAL);
1175 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1178 struct sk_buff *skb;
1181 if (size <= NLMSG_GOODSIZE || broadcast)
1182 return alloc_skb(size, GFP_KERNEL);
1184 size = SKB_DATA_ALIGN(size) +
1185 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1187 data = vmalloc(size);
1191 skb = __build_skb(data, size);
1195 skb->destructor = netlink_skb_destructor;
1201 * Attach a skb to a netlink socket.
1202 * The caller must hold a reference to the destination socket. On error, the
1203 * reference is dropped. The skb is not send to the destination, just all
1204 * all error checks are performed and memory in the queue is reserved.
1206 * < 0: error. skb freed, reference to sock dropped.
1208 * 1: repeat lookup - reference dropped while waiting for socket memory.
1210 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1211 long *timeo, struct sock *ssk)
1213 struct netlink_sock *nlk;
1217 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1218 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1219 DECLARE_WAITQUEUE(wait, current);
1221 if (!ssk || netlink_is_kernel(ssk))
1222 netlink_overrun(sk);
1228 __set_current_state(TASK_INTERRUPTIBLE);
1229 add_wait_queue(&nlk->wait, &wait);
1231 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1232 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1233 !sock_flag(sk, SOCK_DEAD))
1234 *timeo = schedule_timeout(*timeo);
1236 __set_current_state(TASK_RUNNING);
1237 remove_wait_queue(&nlk->wait, &wait);
1240 if (signal_pending(current)) {
1242 return sock_intr_errno(*timeo);
1246 netlink_skb_set_owner_r(skb, sk);
1250 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1254 netlink_deliver_tap(sock_net(sk), skb);
1256 skb_queue_tail(&sk->sk_receive_queue, skb);
1257 sk->sk_data_ready(sk);
1261 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1263 int len = __netlink_sendskb(sk, skb);
1269 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1275 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1279 WARN_ON(skb->sk != NULL);
1280 delta = skb->end - skb->tail;
1281 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1284 if (skb_shared(skb)) {
1285 struct sk_buff *nskb = skb_clone(skb, allocation);
1292 pskb_expand_head(skb, 0, -delta,
1293 (allocation & ~__GFP_DIRECT_RECLAIM) |
1294 __GFP_NOWARN | __GFP_NORETRY);
1298 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1302 struct netlink_sock *nlk = nlk_sk(sk);
1304 ret = -ECONNREFUSED;
1305 if (nlk->netlink_rcv != NULL) {
1307 netlink_skb_set_owner_r(skb, sk);
1308 NETLINK_CB(skb).sk = ssk;
1309 netlink_deliver_tap_kernel(sk, ssk, skb);
1310 nlk->netlink_rcv(skb);
1319 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1320 u32 portid, int nonblock)
1326 skb = netlink_trim(skb, gfp_any());
1328 timeo = sock_sndtimeo(ssk, nonblock);
1330 sk = netlink_getsockbyportid(ssk, portid);
1335 if (netlink_is_kernel(sk))
1336 return netlink_unicast_kernel(sk, skb, ssk);
1338 if (sk_filter(sk, skb)) {
1345 err = netlink_attachskb(sk, skb, &timeo, ssk);
1351 return netlink_sendskb(sk, skb);
1353 EXPORT_SYMBOL(netlink_unicast);
1355 int netlink_has_listeners(struct sock *sk, unsigned int group)
1358 struct listeners *listeners;
1360 BUG_ON(!netlink_is_kernel(sk));
1363 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1365 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1366 res = test_bit(group - 1, listeners->masks);
1372 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1374 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1376 struct netlink_sock *nlk = nlk_sk(sk);
1378 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1379 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1380 netlink_skb_set_owner_r(skb, sk);
1381 __netlink_sendskb(sk, skb);
1382 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1387 struct netlink_broadcast_data {
1388 struct sock *exclude_sk;
1393 int delivery_failure;
1397 struct sk_buff *skb, *skb2;
1398 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1402 static void do_one_broadcast(struct sock *sk,
1403 struct netlink_broadcast_data *p)
1405 struct netlink_sock *nlk = nlk_sk(sk);
1408 if (p->exclude_sk == sk)
1411 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1412 !test_bit(p->group - 1, nlk->groups))
1415 if (!net_eq(sock_net(sk), p->net)) {
1416 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1419 if (!peernet_has_id(sock_net(sk), p->net))
1422 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1428 netlink_overrun(sk);
1433 if (p->skb2 == NULL) {
1434 if (skb_shared(p->skb)) {
1435 p->skb2 = skb_clone(p->skb, p->allocation);
1437 p->skb2 = skb_get(p->skb);
1439 * skb ownership may have been set when
1440 * delivered to a previous socket.
1442 skb_orphan(p->skb2);
1445 if (p->skb2 == NULL) {
1446 netlink_overrun(sk);
1447 /* Clone failed. Notify ALL listeners. */
1449 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1450 p->delivery_failure = 1;
1453 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1458 if (sk_filter(sk, p->skb2)) {
1463 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1464 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1465 NETLINK_CB(p->skb2).nsid_is_set = true;
1466 val = netlink_broadcast_deliver(sk, p->skb2);
1468 netlink_overrun(sk);
1469 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1470 p->delivery_failure = 1;
1472 p->congested |= val;
1480 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1481 u32 group, gfp_t allocation,
1482 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1485 struct net *net = sock_net(ssk);
1486 struct netlink_broadcast_data info;
1489 skb = netlink_trim(skb, allocation);
1491 info.exclude_sk = ssk;
1493 info.portid = portid;
1496 info.delivery_failure = 0;
1499 info.allocation = allocation;
1502 info.tx_filter = filter;
1503 info.tx_data = filter_data;
1505 /* While we sleep in clone, do not allow to change socket list */
1507 netlink_lock_table();
1509 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1510 do_one_broadcast(sk, &info);
1514 netlink_unlock_table();
1516 if (info.delivery_failure) {
1517 kfree_skb(info.skb2);
1520 consume_skb(info.skb2);
1522 if (info.delivered) {
1523 if (info.congested && gfpflags_allow_blocking(allocation))
1529 EXPORT_SYMBOL(netlink_broadcast_filtered);
1531 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1532 u32 group, gfp_t allocation)
1534 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1537 EXPORT_SYMBOL(netlink_broadcast);
1539 struct netlink_set_err_data {
1540 struct sock *exclude_sk;
1546 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1548 struct netlink_sock *nlk = nlk_sk(sk);
1551 if (sk == p->exclude_sk)
1554 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1557 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1558 !test_bit(p->group - 1, nlk->groups))
1561 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1566 sk->sk_err = p->code;
1567 sk->sk_error_report(sk);
1573 * netlink_set_err - report error to broadcast listeners
1574 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1575 * @portid: the PORTID of a process that we want to skip (if any)
1576 * @group: the broadcast group that will notice the error
1577 * @code: error code, must be negative (as usual in kernelspace)
1579 * This function returns the number of broadcast listeners that have set the
1580 * NETLINK_NO_ENOBUFS socket option.
1582 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1584 struct netlink_set_err_data info;
1588 info.exclude_sk = ssk;
1589 info.portid = portid;
1591 /* sk->sk_err wants a positive error value */
1594 read_lock(&nl_table_lock);
1596 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1597 ret += do_one_set_err(sk, &info);
1599 read_unlock(&nl_table_lock);
1602 EXPORT_SYMBOL(netlink_set_err);
1604 /* must be called with netlink table grabbed */
1605 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1609 int old, new = !!is_new, subscriptions;
1611 old = test_bit(group - 1, nlk->groups);
1612 subscriptions = nlk->subscriptions - old + new;
1614 __set_bit(group - 1, nlk->groups);
1616 __clear_bit(group - 1, nlk->groups);
1617 netlink_update_subscriptions(&nlk->sk, subscriptions);
1618 netlink_update_listeners(&nlk->sk);
1621 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1622 char __user *optval, unsigned int optlen)
1624 struct sock *sk = sock->sk;
1625 struct netlink_sock *nlk = nlk_sk(sk);
1626 unsigned int val = 0;
1629 if (level != SOL_NETLINK)
1630 return -ENOPROTOOPT;
1632 if (optlen >= sizeof(int) &&
1633 get_user(val, (unsigned int __user *)optval))
1637 case NETLINK_PKTINFO:
1639 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1641 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1644 case NETLINK_ADD_MEMBERSHIP:
1645 case NETLINK_DROP_MEMBERSHIP: {
1646 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1648 err = netlink_realloc_groups(sk);
1651 if (!val || val - 1 >= nlk->ngroups)
1653 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1654 err = nlk->netlink_bind(sock_net(sk), val);
1658 netlink_table_grab();
1659 netlink_update_socket_mc(nlk, val,
1660 optname == NETLINK_ADD_MEMBERSHIP);
1661 netlink_table_ungrab();
1662 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1663 nlk->netlink_unbind(sock_net(sk), val);
1668 case NETLINK_BROADCAST_ERROR:
1670 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1672 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1675 case NETLINK_NO_ENOBUFS:
1677 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1678 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1679 wake_up_interruptible(&nlk->wait);
1681 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1685 case NETLINK_LISTEN_ALL_NSID:
1686 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1690 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1692 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1695 case NETLINK_CAP_ACK:
1697 nlk->flags |= NETLINK_F_CAP_ACK;
1699 nlk->flags &= ~NETLINK_F_CAP_ACK;
1702 case NETLINK_EXT_ACK:
1704 nlk->flags |= NETLINK_F_EXT_ACK;
1706 nlk->flags &= ~NETLINK_F_EXT_ACK;
1715 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1716 char __user *optval, int __user *optlen)
1718 struct sock *sk = sock->sk;
1719 struct netlink_sock *nlk = nlk_sk(sk);
1722 if (level != SOL_NETLINK)
1723 return -ENOPROTOOPT;
1725 if (get_user(len, optlen))
1731 case NETLINK_PKTINFO:
1732 if (len < sizeof(int))
1735 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1736 if (put_user(len, optlen) ||
1737 put_user(val, optval))
1741 case NETLINK_BROADCAST_ERROR:
1742 if (len < sizeof(int))
1745 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1746 if (put_user(len, optlen) ||
1747 put_user(val, optval))
1751 case NETLINK_NO_ENOBUFS:
1752 if (len < sizeof(int))
1755 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1756 if (put_user(len, optlen) ||
1757 put_user(val, optval))
1761 case NETLINK_LIST_MEMBERSHIPS: {
1762 int pos, idx, shift;
1765 netlink_lock_table();
1766 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1767 if (len - pos < sizeof(u32))
1770 idx = pos / sizeof(unsigned long);
1771 shift = (pos % sizeof(unsigned long)) * 8;
1772 if (put_user((u32)(nlk->groups[idx] >> shift),
1773 (u32 __user *)(optval + pos))) {
1778 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1780 netlink_unlock_table();
1783 case NETLINK_CAP_ACK:
1784 if (len < sizeof(int))
1787 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1788 if (put_user(len, optlen) ||
1789 put_user(val, optval))
1793 case NETLINK_EXT_ACK:
1794 if (len < sizeof(int))
1797 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1798 if (put_user(len, optlen) || put_user(val, optval))
1808 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1810 struct nl_pktinfo info;
1812 info.group = NETLINK_CB(skb).dst_group;
1813 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1816 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1817 struct sk_buff *skb)
1819 if (!NETLINK_CB(skb).nsid_is_set)
1822 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1823 &NETLINK_CB(skb).nsid);
1826 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1828 struct sock *sk = sock->sk;
1829 struct netlink_sock *nlk = nlk_sk(sk);
1830 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1833 struct sk_buff *skb;
1835 struct scm_cookie scm;
1836 u32 netlink_skb_flags = 0;
1838 if (msg->msg_flags&MSG_OOB)
1841 err = scm_send(sock, msg, &scm, true);
1845 if (msg->msg_namelen) {
1847 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1849 if (addr->nl_family != AF_NETLINK)
1851 dst_portid = addr->nl_pid;
1852 dst_group = ffs(addr->nl_groups);
1854 if ((dst_group || dst_portid) &&
1855 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1857 netlink_skb_flags |= NETLINK_SKB_DST;
1859 dst_portid = nlk->dst_portid;
1860 dst_group = nlk->dst_group;
1864 err = netlink_autobind(sock);
1868 /* Ensure nlk is hashed and visible. */
1873 if (len > sk->sk_sndbuf - 32)
1876 skb = netlink_alloc_large_skb(len, dst_group);
1880 NETLINK_CB(skb).portid = nlk->portid;
1881 NETLINK_CB(skb).dst_group = dst_group;
1882 NETLINK_CB(skb).creds = scm.creds;
1883 NETLINK_CB(skb).flags = netlink_skb_flags;
1886 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1891 err = security_netlink_send(sk, skb);
1898 refcount_inc(&skb->users);
1899 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1901 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1908 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1911 struct scm_cookie scm;
1912 struct sock *sk = sock->sk;
1913 struct netlink_sock *nlk = nlk_sk(sk);
1914 int noblock = flags&MSG_DONTWAIT;
1916 struct sk_buff *skb, *data_skb;
1924 skb = skb_recv_datagram(sk, flags, noblock, &err);
1930 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1931 if (unlikely(skb_shinfo(skb)->frag_list)) {
1933 * If this skb has a frag_list, then here that means that we
1934 * will have to use the frag_list skb's data for compat tasks
1935 * and the regular skb's data for normal (non-compat) tasks.
1937 * If we need to send the compat skb, assign it to the
1938 * 'data_skb' variable so that it will be used below for data
1939 * copying. We keep 'skb' for everything else, including
1940 * freeing both later.
1942 if (flags & MSG_CMSG_COMPAT)
1943 data_skb = skb_shinfo(skb)->frag_list;
1947 /* Record the max length of recvmsg() calls for future allocations */
1948 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1949 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1950 SKB_WITH_OVERHEAD(32768));
1952 copied = data_skb->len;
1954 msg->msg_flags |= MSG_TRUNC;
1958 skb_reset_transport_header(data_skb);
1959 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1961 if (msg->msg_name) {
1962 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1963 addr->nl_family = AF_NETLINK;
1965 addr->nl_pid = NETLINK_CB(skb).portid;
1966 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1967 msg->msg_namelen = sizeof(*addr);
1970 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1971 netlink_cmsg_recv_pktinfo(msg, skb);
1972 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1973 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1975 memset(&scm, 0, sizeof(scm));
1976 scm.creds = *NETLINK_CREDS(skb);
1977 if (flags & MSG_TRUNC)
1978 copied = data_skb->len;
1980 skb_free_datagram(sk, skb);
1982 if (nlk->cb_running &&
1983 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1984 ret = netlink_dump(sk);
1987 sk->sk_error_report(sk);
1991 scm_recv(sock, msg, &scm, flags);
1993 netlink_rcv_wake(sk);
1994 return err ? : copied;
1997 static void netlink_data_ready(struct sock *sk)
2003 * We export these functions to other modules. They provide a
2004 * complete set of kernel non-blocking support for message
2009 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2010 struct netlink_kernel_cfg *cfg)
2012 struct socket *sock;
2014 struct netlink_sock *nlk;
2015 struct listeners *listeners = NULL;
2016 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2017 unsigned int groups;
2021 if (unit < 0 || unit >= MAX_LINKS)
2024 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2027 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2028 goto out_sock_release_nosk;
2032 if (!cfg || cfg->groups < 32)
2035 groups = cfg->groups;
2037 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2039 goto out_sock_release;
2041 sk->sk_data_ready = netlink_data_ready;
2042 if (cfg && cfg->input)
2043 nlk_sk(sk)->netlink_rcv = cfg->input;
2045 if (netlink_insert(sk, 0))
2046 goto out_sock_release;
2049 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2051 netlink_table_grab();
2052 if (!nl_table[unit].registered) {
2053 nl_table[unit].groups = groups;
2054 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2055 nl_table[unit].cb_mutex = cb_mutex;
2056 nl_table[unit].module = module;
2058 nl_table[unit].bind = cfg->bind;
2059 nl_table[unit].unbind = cfg->unbind;
2060 nl_table[unit].flags = cfg->flags;
2062 nl_table[unit].compare = cfg->compare;
2064 nl_table[unit].registered = 1;
2067 nl_table[unit].registered++;
2069 netlink_table_ungrab();
2074 netlink_kernel_release(sk);
2077 out_sock_release_nosk:
2081 EXPORT_SYMBOL(__netlink_kernel_create);
2084 netlink_kernel_release(struct sock *sk)
2086 if (sk == NULL || sk->sk_socket == NULL)
2089 sock_release(sk->sk_socket);
2091 EXPORT_SYMBOL(netlink_kernel_release);
2093 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2095 struct listeners *new, *old;
2096 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2101 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2102 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2105 old = nl_deref_protected(tbl->listeners);
2106 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2107 rcu_assign_pointer(tbl->listeners, new);
2109 kfree_rcu(old, rcu);
2111 tbl->groups = groups;
2117 * netlink_change_ngroups - change number of multicast groups
2119 * This changes the number of multicast groups that are available
2120 * on a certain netlink family. Note that it is not possible to
2121 * change the number of groups to below 32. Also note that it does
2122 * not implicitly call netlink_clear_multicast_users() when the
2123 * number of groups is reduced.
2125 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2126 * @groups: The new number of groups.
2128 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2132 netlink_table_grab();
2133 err = __netlink_change_ngroups(sk, groups);
2134 netlink_table_ungrab();
2139 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2142 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2144 sk_for_each_bound(sk, &tbl->mc_list)
2145 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2149 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2151 struct nlmsghdr *nlh;
2152 int size = nlmsg_msg_size(len);
2154 nlh = skb_put(skb, NLMSG_ALIGN(size));
2155 nlh->nlmsg_type = type;
2156 nlh->nlmsg_len = size;
2157 nlh->nlmsg_flags = flags;
2158 nlh->nlmsg_pid = portid;
2159 nlh->nlmsg_seq = seq;
2160 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2161 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2164 EXPORT_SYMBOL(__nlmsg_put);
2167 * It looks a bit ugly.
2168 * It would be better to create kernel thread.
2171 static int netlink_dump(struct sock *sk)
2173 struct netlink_sock *nlk = nlk_sk(sk);
2174 struct netlink_callback *cb;
2175 struct sk_buff *skb = NULL;
2176 struct nlmsghdr *nlh;
2177 struct module *module;
2182 mutex_lock(nlk->cb_mutex);
2183 if (!nlk->cb_running) {
2188 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2191 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2192 * required, but it makes sense to _attempt_ a 16K bytes allocation
2193 * to reduce number of system calls on dump operations, if user
2194 * ever provided a big enough buffer.
2197 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2199 if (alloc_min_size < nlk->max_recvmsg_len) {
2200 alloc_size = nlk->max_recvmsg_len;
2201 skb = alloc_skb(alloc_size,
2202 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2203 __GFP_NOWARN | __GFP_NORETRY);
2206 alloc_size = alloc_min_size;
2207 skb = alloc_skb(alloc_size, GFP_KERNEL);
2212 /* Trim skb to allocated size. User is expected to provide buffer as
2213 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2214 * netlink_recvmsg())). dump will pack as many smaller messages as
2215 * could fit within the allocated skb. skb is typically allocated
2216 * with larger space than required (could be as much as near 2x the
2217 * requested size with align to next power of 2 approach). Allowing
2218 * dump to use the excess space makes it difficult for a user to have a
2219 * reasonable static buffer based on the expected largest dump of a
2220 * single netdev. The outcome is MSG_TRUNC error.
2222 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2223 netlink_skb_set_owner_r(skb, sk);
2225 if (nlk->dump_done_errno > 0)
2226 nlk->dump_done_errno = cb->dump(skb, cb);
2228 if (nlk->dump_done_errno > 0 ||
2229 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2230 mutex_unlock(nlk->cb_mutex);
2232 if (sk_filter(sk, skb))
2235 __netlink_sendskb(sk, skb);
2239 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
2240 sizeof(nlk->dump_done_errno), NLM_F_MULTI);
2244 nl_dump_check_consistent(cb, nlh);
2246 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
2247 sizeof(nlk->dump_done_errno));
2249 if (sk_filter(sk, skb))
2252 __netlink_sendskb(sk, skb);
2257 nlk->cb_running = false;
2258 module = cb->module;
2260 mutex_unlock(nlk->cb_mutex);
2266 mutex_unlock(nlk->cb_mutex);
2271 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2272 const struct nlmsghdr *nlh,
2273 struct netlink_dump_control *control)
2275 struct netlink_callback *cb;
2277 struct netlink_sock *nlk;
2280 refcount_inc(&skb->users);
2282 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2284 ret = -ECONNREFUSED;
2289 mutex_lock(nlk->cb_mutex);
2290 /* A dump is in progress... */
2291 if (nlk->cb_running) {
2295 /* add reference of module which cb->dump belongs to */
2296 if (!try_module_get(control->module)) {
2297 ret = -EPROTONOSUPPORT;
2302 memset(cb, 0, sizeof(*cb));
2303 cb->start = control->start;
2304 cb->dump = control->dump;
2305 cb->done = control->done;
2307 cb->data = control->data;
2308 cb->module = control->module;
2309 cb->min_dump_alloc = control->min_dump_alloc;
2313 ret = cb->start(cb);
2318 nlk->cb_running = true;
2319 nlk->dump_done_errno = INT_MAX;
2321 mutex_unlock(nlk->cb_mutex);
2323 ret = netlink_dump(sk);
2330 /* We successfully started a dump, by returning -EINTR we
2331 * signal not to send ACK even if it was requested.
2336 module_put(control->module);
2339 mutex_unlock(nlk->cb_mutex);
2344 EXPORT_SYMBOL(__netlink_dump_start);
2346 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2347 const struct netlink_ext_ack *extack)
2349 struct sk_buff *skb;
2350 struct nlmsghdr *rep;
2351 struct nlmsgerr *errmsg;
2352 size_t payload = sizeof(*errmsg);
2354 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2355 unsigned int flags = 0;
2356 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK;
2358 /* Error messages get the original request appened, unless the user
2359 * requests to cap the error message, and get extra error data if
2362 if (nlk_has_extack && extack && extack->_msg)
2363 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2366 if (!(nlk->flags & NETLINK_F_CAP_ACK))
2367 payload += nlmsg_len(nlh);
2369 flags |= NLM_F_CAPPED;
2370 if (nlk_has_extack && extack && extack->bad_attr)
2371 tlvlen += nla_total_size(sizeof(u32));
2373 flags |= NLM_F_CAPPED;
2375 if (nlk_has_extack && extack && extack->cookie_len)
2376 tlvlen += nla_total_size(extack->cookie_len);
2380 flags |= NLM_F_ACK_TLVS;
2382 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2384 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
2385 NETLINK_CB(in_skb).sk->sk_error_report(NETLINK_CB(in_skb).sk);
2389 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2390 NLMSG_ERROR, payload, flags);
2391 errmsg = nlmsg_data(rep);
2392 errmsg->error = err;
2393 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2395 if (nlk_has_extack && extack) {
2397 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2401 if (extack->bad_attr &&
2402 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2403 (u8 *)extack->bad_attr >= in_skb->data +
2405 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2406 (u8 *)extack->bad_attr -
2409 if (extack->cookie_len)
2410 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2416 nlmsg_end(skb, rep);
2418 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2420 EXPORT_SYMBOL(netlink_ack);
2422 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2424 struct netlink_ext_ack *))
2426 struct netlink_ext_ack extack;
2427 struct nlmsghdr *nlh;
2430 while (skb->len >= nlmsg_total_size(0)) {
2433 memset(&extack, 0, sizeof(extack));
2434 nlh = nlmsg_hdr(skb);
2437 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2440 /* Only requests are handled by the kernel */
2441 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2444 /* Skip control messages */
2445 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2448 err = cb(skb, nlh, &extack);
2453 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2454 netlink_ack(skb, nlh, err, &extack);
2457 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2458 if (msglen > skb->len)
2460 skb_pull(skb, msglen);
2465 EXPORT_SYMBOL(netlink_rcv_skb);
2468 * nlmsg_notify - send a notification netlink message
2469 * @sk: netlink socket to use
2470 * @skb: notification message
2471 * @portid: destination netlink portid for reports or 0
2472 * @group: destination multicast group or 0
2473 * @report: 1 to report back, 0 to disable
2474 * @flags: allocation flags
2476 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2477 unsigned int group, int report, gfp_t flags)
2482 int exclude_portid = 0;
2485 refcount_inc(&skb->users);
2486 exclude_portid = portid;
2489 /* errors reported via destination sk->sk_err, but propagate
2490 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2491 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2497 err2 = nlmsg_unicast(sk, skb, portid);
2498 if (!err || err == -ESRCH)
2504 EXPORT_SYMBOL(nlmsg_notify);
2506 #ifdef CONFIG_PROC_FS
2507 struct nl_seq_iter {
2508 struct seq_net_private p;
2509 struct rhashtable_iter hti;
2513 static int netlink_walk_start(struct nl_seq_iter *iter)
2517 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
2520 iter->link = MAX_LINKS;
2524 rhashtable_walk_start(&iter->hti);
2529 static void netlink_walk_stop(struct nl_seq_iter *iter)
2531 rhashtable_walk_stop(&iter->hti);
2532 rhashtable_walk_exit(&iter->hti);
2535 static void *__netlink_seq_next(struct seq_file *seq)
2537 struct nl_seq_iter *iter = seq->private;
2538 struct netlink_sock *nlk;
2544 nlk = rhashtable_walk_next(&iter->hti);
2547 if (PTR_ERR(nlk) == -EAGAIN)
2556 netlink_walk_stop(iter);
2557 if (++iter->link >= MAX_LINKS)
2560 err = netlink_walk_start(iter);
2562 return ERR_PTR(err);
2564 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2569 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2571 struct nl_seq_iter *iter = seq->private;
2572 void *obj = SEQ_START_TOKEN;
2578 err = netlink_walk_start(iter);
2580 return ERR_PTR(err);
2582 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2583 obj = __netlink_seq_next(seq);
2588 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2591 return __netlink_seq_next(seq);
2594 static void netlink_seq_stop(struct seq_file *seq, void *v)
2596 struct nl_seq_iter *iter = seq->private;
2598 if (iter->link >= MAX_LINKS)
2601 netlink_walk_stop(iter);
2605 static int netlink_seq_show(struct seq_file *seq, void *v)
2607 if (v == SEQ_START_TOKEN) {
2609 "sk Eth Pid Groups "
2610 "Rmem Wmem Dump Locks Drops Inode\n");
2613 struct netlink_sock *nlk = nlk_sk(s);
2615 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2619 nlk->groups ? (u32)nlk->groups[0] : 0,
2620 sk_rmem_alloc_get(s),
2621 sk_wmem_alloc_get(s),
2623 refcount_read(&s->sk_refcnt),
2624 atomic_read(&s->sk_drops),
2632 static const struct seq_operations netlink_seq_ops = {
2633 .start = netlink_seq_start,
2634 .next = netlink_seq_next,
2635 .stop = netlink_seq_stop,
2636 .show = netlink_seq_show,
2640 static int netlink_seq_open(struct inode *inode, struct file *file)
2642 return seq_open_net(inode, file, &netlink_seq_ops,
2643 sizeof(struct nl_seq_iter));
2646 static const struct file_operations netlink_seq_fops = {
2647 .open = netlink_seq_open,
2649 .llseek = seq_lseek,
2650 .release = seq_release_net,
2655 int netlink_register_notifier(struct notifier_block *nb)
2657 return blocking_notifier_chain_register(&netlink_chain, nb);
2659 EXPORT_SYMBOL(netlink_register_notifier);
2661 int netlink_unregister_notifier(struct notifier_block *nb)
2663 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2665 EXPORT_SYMBOL(netlink_unregister_notifier);
2667 static const struct proto_ops netlink_ops = {
2668 .family = PF_NETLINK,
2669 .owner = THIS_MODULE,
2670 .release = netlink_release,
2671 .bind = netlink_bind,
2672 .connect = netlink_connect,
2673 .socketpair = sock_no_socketpair,
2674 .accept = sock_no_accept,
2675 .getname = netlink_getname,
2676 .poll = datagram_poll,
2677 .ioctl = netlink_ioctl,
2678 .listen = sock_no_listen,
2679 .shutdown = sock_no_shutdown,
2680 .setsockopt = netlink_setsockopt,
2681 .getsockopt = netlink_getsockopt,
2682 .sendmsg = netlink_sendmsg,
2683 .recvmsg = netlink_recvmsg,
2684 .mmap = sock_no_mmap,
2685 .sendpage = sock_no_sendpage,
2688 static const struct net_proto_family netlink_family_ops = {
2689 .family = PF_NETLINK,
2690 .create = netlink_create,
2691 .owner = THIS_MODULE, /* for consistency 8) */
2694 static int __net_init netlink_net_init(struct net *net)
2696 #ifdef CONFIG_PROC_FS
2697 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2703 static void __net_exit netlink_net_exit(struct net *net)
2705 #ifdef CONFIG_PROC_FS
2706 remove_proc_entry("netlink", net->proc_net);
2710 static void __init netlink_add_usersock_entry(void)
2712 struct listeners *listeners;
2715 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2717 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2719 netlink_table_grab();
2721 nl_table[NETLINK_USERSOCK].groups = groups;
2722 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2723 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2724 nl_table[NETLINK_USERSOCK].registered = 1;
2725 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2727 netlink_table_ungrab();
2730 static struct pernet_operations __net_initdata netlink_net_ops = {
2731 .init = netlink_net_init,
2732 .exit = netlink_net_exit,
2735 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2737 const struct netlink_sock *nlk = data;
2738 struct netlink_compare_arg arg;
2740 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2741 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2744 static const struct rhashtable_params netlink_rhashtable_params = {
2745 .head_offset = offsetof(struct netlink_sock, node),
2746 .key_len = netlink_compare_arg_len,
2747 .obj_hashfn = netlink_hash,
2748 .obj_cmpfn = netlink_compare,
2749 .automatic_shrinking = true,
2752 static int __init netlink_proto_init(void)
2755 int err = proto_register(&netlink_proto, 0);
2760 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2762 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2766 for (i = 0; i < MAX_LINKS; i++) {
2767 if (rhashtable_init(&nl_table[i].hash,
2768 &netlink_rhashtable_params) < 0) {
2770 rhashtable_destroy(&nl_table[i].hash);
2776 netlink_add_usersock_entry();
2778 sock_register(&netlink_family_ops);
2779 register_pernet_subsys(&netlink_net_ops);
2780 register_pernet_subsys(&netlink_tap_net_ops);
2781 /* The netlink device handler may be needed early. */
2786 panic("netlink_init: Cannot allocate nl_table\n");
2789 core_initcall(netlink_proto_init);