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 <asm/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>
66 #include <net/net_namespace.h>
69 #include <net/netlink.h>
71 #include "af_netlink.h"
75 unsigned long masks[0];
79 #define NETLINK_CONGESTED 0x0
82 #define NETLINK_KERNEL_SOCKET 0x1
83 #define NETLINK_RECV_PKTINFO 0x2
84 #define NETLINK_BROADCAST_SEND_ERROR 0x4
85 #define NETLINK_RECV_NO_ENOBUFS 0x8
87 static inline int netlink_is_kernel(struct sock *sk)
89 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
92 struct netlink_table *nl_table;
93 EXPORT_SYMBOL_GPL(nl_table);
95 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
97 static int netlink_dump(struct sock *sk);
98 static void netlink_skb_destructor(struct sk_buff *skb);
100 /* nl_table locking explained:
101 * Lookup and traversal are protected with nl_sk_hash_lock or nl_table_lock
102 * combined with an RCU read-side lock. Insertion and removal are protected
103 * with nl_sk_hash_lock while using RCU list modification primitives and may
104 * run in parallel to nl_table_lock protected lookups. Destruction of the
105 * Netlink socket may only occur *after* nl_table_lock has been acquired
106 * either during or after the socket has been removed from the list.
108 DEFINE_RWLOCK(nl_table_lock);
109 EXPORT_SYMBOL_GPL(nl_table_lock);
110 static atomic_t nl_table_users = ATOMIC_INIT(0);
112 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
114 /* Protects netlink socket hash table mutations */
115 DEFINE_MUTEX(nl_sk_hash_lock);
116 EXPORT_SYMBOL_GPL(nl_sk_hash_lock);
118 #ifdef CONFIG_PROVE_LOCKING
119 static int lockdep_nl_sk_hash_is_held(void *parent)
122 return lockdep_is_held(&nl_sk_hash_lock) || lockdep_is_held(&nl_table_lock);
127 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
129 static DEFINE_SPINLOCK(netlink_tap_lock);
130 static struct list_head netlink_tap_all __read_mostly;
132 static inline u32 netlink_group_mask(u32 group)
134 return group ? 1 << (group - 1) : 0;
137 int netlink_add_tap(struct netlink_tap *nt)
139 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
142 spin_lock(&netlink_tap_lock);
143 list_add_rcu(&nt->list, &netlink_tap_all);
144 spin_unlock(&netlink_tap_lock);
146 __module_get(nt->module);
150 EXPORT_SYMBOL_GPL(netlink_add_tap);
152 static int __netlink_remove_tap(struct netlink_tap *nt)
155 struct netlink_tap *tmp;
157 spin_lock(&netlink_tap_lock);
159 list_for_each_entry(tmp, &netlink_tap_all, list) {
161 list_del_rcu(&nt->list);
167 pr_warn("__netlink_remove_tap: %p not found\n", nt);
169 spin_unlock(&netlink_tap_lock);
171 if (found && nt->module)
172 module_put(nt->module);
174 return found ? 0 : -ENODEV;
177 int netlink_remove_tap(struct netlink_tap *nt)
181 ret = __netlink_remove_tap(nt);
186 EXPORT_SYMBOL_GPL(netlink_remove_tap);
188 static bool netlink_filter_tap(const struct sk_buff *skb)
190 struct sock *sk = skb->sk;
192 /* We take the more conservative approach and
193 * whitelist socket protocols that may pass.
195 switch (sk->sk_protocol) {
197 case NETLINK_USERSOCK:
198 case NETLINK_SOCK_DIAG:
201 case NETLINK_FIB_LOOKUP:
202 case NETLINK_NETFILTER:
203 case NETLINK_GENERIC:
210 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
211 struct net_device *dev)
213 struct sk_buff *nskb;
214 struct sock *sk = skb->sk;
218 nskb = skb_clone(skb, GFP_ATOMIC);
221 nskb->protocol = htons((u16) sk->sk_protocol);
222 nskb->pkt_type = netlink_is_kernel(sk) ?
223 PACKET_KERNEL : PACKET_USER;
224 skb_reset_network_header(nskb);
225 ret = dev_queue_xmit(nskb);
226 if (unlikely(ret > 0))
227 ret = net_xmit_errno(ret);
234 static void __netlink_deliver_tap(struct sk_buff *skb)
237 struct netlink_tap *tmp;
239 if (!netlink_filter_tap(skb))
242 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
243 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
249 static void netlink_deliver_tap(struct sk_buff *skb)
253 if (unlikely(!list_empty(&netlink_tap_all)))
254 __netlink_deliver_tap(skb);
259 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
262 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
263 netlink_deliver_tap(skb);
266 static void netlink_overrun(struct sock *sk)
268 struct netlink_sock *nlk = nlk_sk(sk);
270 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
271 if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
272 sk->sk_err = ENOBUFS;
273 sk->sk_error_report(sk);
276 atomic_inc(&sk->sk_drops);
279 static void netlink_rcv_wake(struct sock *sk)
281 struct netlink_sock *nlk = nlk_sk(sk);
283 if (skb_queue_empty(&sk->sk_receive_queue))
284 clear_bit(NETLINK_CONGESTED, &nlk->state);
285 if (!test_bit(NETLINK_CONGESTED, &nlk->state))
286 wake_up_interruptible(&nlk->wait);
289 #ifdef CONFIG_NETLINK_MMAP
290 static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
292 return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
295 static bool netlink_rx_is_mmaped(struct sock *sk)
297 return nlk_sk(sk)->rx_ring.pg_vec != NULL;
300 static bool netlink_tx_is_mmaped(struct sock *sk)
302 return nlk_sk(sk)->tx_ring.pg_vec != NULL;
305 static __pure struct page *pgvec_to_page(const void *addr)
307 if (is_vmalloc_addr(addr))
308 return vmalloc_to_page(addr);
310 return virt_to_page(addr);
313 static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
317 for (i = 0; i < len; i++) {
318 if (pg_vec[i] != NULL) {
319 if (is_vmalloc_addr(pg_vec[i]))
322 free_pages((unsigned long)pg_vec[i], order);
328 static void *alloc_one_pg_vec_page(unsigned long order)
331 gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
332 __GFP_NOWARN | __GFP_NORETRY;
334 buffer = (void *)__get_free_pages(gfp_flags, order);
338 buffer = vzalloc((1 << order) * PAGE_SIZE);
342 gfp_flags &= ~__GFP_NORETRY;
343 return (void *)__get_free_pages(gfp_flags, order);
346 static void **alloc_pg_vec(struct netlink_sock *nlk,
347 struct nl_mmap_req *req, unsigned int order)
349 unsigned int block_nr = req->nm_block_nr;
353 pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
357 for (i = 0; i < block_nr; i++) {
358 pg_vec[i] = alloc_one_pg_vec_page(order);
359 if (pg_vec[i] == NULL)
365 free_pg_vec(pg_vec, order, block_nr);
369 static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
370 bool closing, bool tx_ring)
372 struct netlink_sock *nlk = nlk_sk(sk);
373 struct netlink_ring *ring;
374 struct sk_buff_head *queue;
375 void **pg_vec = NULL;
376 unsigned int order = 0;
379 ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
380 queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
383 if (atomic_read(&nlk->mapped))
385 if (atomic_read(&ring->pending))
389 if (req->nm_block_nr) {
390 if (ring->pg_vec != NULL)
393 if ((int)req->nm_block_size <= 0)
395 if (!PAGE_ALIGNED(req->nm_block_size))
397 if (req->nm_frame_size < NL_MMAP_HDRLEN)
399 if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
402 ring->frames_per_block = req->nm_block_size /
404 if (ring->frames_per_block == 0)
406 if (ring->frames_per_block * req->nm_block_nr !=
410 order = get_order(req->nm_block_size);
411 pg_vec = alloc_pg_vec(nlk, req, order);
415 if (req->nm_frame_nr)
420 mutex_lock(&nlk->pg_vec_lock);
421 if (closing || atomic_read(&nlk->mapped) == 0) {
423 spin_lock_bh(&queue->lock);
425 ring->frame_max = req->nm_frame_nr - 1;
427 ring->frame_size = req->nm_frame_size;
428 ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
430 swap(ring->pg_vec_len, req->nm_block_nr);
431 swap(ring->pg_vec_order, order);
432 swap(ring->pg_vec, pg_vec);
434 __skb_queue_purge(queue);
435 spin_unlock_bh(&queue->lock);
437 WARN_ON(atomic_read(&nlk->mapped));
439 mutex_unlock(&nlk->pg_vec_lock);
442 free_pg_vec(pg_vec, order, req->nm_block_nr);
446 static void netlink_mm_open(struct vm_area_struct *vma)
448 struct file *file = vma->vm_file;
449 struct socket *sock = file->private_data;
450 struct sock *sk = sock->sk;
453 atomic_inc(&nlk_sk(sk)->mapped);
456 static void netlink_mm_close(struct vm_area_struct *vma)
458 struct file *file = vma->vm_file;
459 struct socket *sock = file->private_data;
460 struct sock *sk = sock->sk;
463 atomic_dec(&nlk_sk(sk)->mapped);
466 static const struct vm_operations_struct netlink_mmap_ops = {
467 .open = netlink_mm_open,
468 .close = netlink_mm_close,
471 static int netlink_mmap(struct file *file, struct socket *sock,
472 struct vm_area_struct *vma)
474 struct sock *sk = sock->sk;
475 struct netlink_sock *nlk = nlk_sk(sk);
476 struct netlink_ring *ring;
477 unsigned long start, size, expected;
484 mutex_lock(&nlk->pg_vec_lock);
487 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
488 if (ring->pg_vec == NULL)
490 expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
496 size = vma->vm_end - vma->vm_start;
497 if (size != expected)
500 start = vma->vm_start;
501 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
502 if (ring->pg_vec == NULL)
505 for (i = 0; i < ring->pg_vec_len; i++) {
507 void *kaddr = ring->pg_vec[i];
510 for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
511 page = pgvec_to_page(kaddr);
512 err = vm_insert_page(vma, start, page);
521 atomic_inc(&nlk->mapped);
522 vma->vm_ops = &netlink_mmap_ops;
525 mutex_unlock(&nlk->pg_vec_lock);
529 static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr, unsigned int nm_len)
531 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
532 struct page *p_start, *p_end;
534 /* First page is flushed through netlink_{get,set}_status */
535 p_start = pgvec_to_page(hdr + PAGE_SIZE);
536 p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + nm_len - 1);
537 while (p_start <= p_end) {
538 flush_dcache_page(p_start);
544 static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
547 flush_dcache_page(pgvec_to_page(hdr));
548 return hdr->nm_status;
551 static void netlink_set_status(struct nl_mmap_hdr *hdr,
552 enum nl_mmap_status status)
555 hdr->nm_status = status;
556 flush_dcache_page(pgvec_to_page(hdr));
559 static struct nl_mmap_hdr *
560 __netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
562 unsigned int pg_vec_pos, frame_off;
564 pg_vec_pos = pos / ring->frames_per_block;
565 frame_off = pos % ring->frames_per_block;
567 return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
570 static struct nl_mmap_hdr *
571 netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
572 enum nl_mmap_status status)
574 struct nl_mmap_hdr *hdr;
576 hdr = __netlink_lookup_frame(ring, pos);
577 if (netlink_get_status(hdr) != status)
583 static struct nl_mmap_hdr *
584 netlink_current_frame(const struct netlink_ring *ring,
585 enum nl_mmap_status status)
587 return netlink_lookup_frame(ring, ring->head, status);
590 static struct nl_mmap_hdr *
591 netlink_previous_frame(const struct netlink_ring *ring,
592 enum nl_mmap_status status)
596 prev = ring->head ? ring->head - 1 : ring->frame_max;
597 return netlink_lookup_frame(ring, prev, status);
600 static void netlink_increment_head(struct netlink_ring *ring)
602 ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
605 static void netlink_forward_ring(struct netlink_ring *ring)
607 unsigned int head = ring->head, pos = head;
608 const struct nl_mmap_hdr *hdr;
611 hdr = __netlink_lookup_frame(ring, pos);
612 if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
614 if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
616 netlink_increment_head(ring);
617 } while (ring->head != head);
620 static bool netlink_dump_space(struct netlink_sock *nlk)
622 struct netlink_ring *ring = &nlk->rx_ring;
623 struct nl_mmap_hdr *hdr;
626 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
630 n = ring->head + ring->frame_max / 2;
631 if (n > ring->frame_max)
632 n -= ring->frame_max;
634 hdr = __netlink_lookup_frame(ring, n);
636 return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
639 static unsigned int netlink_poll(struct file *file, struct socket *sock,
642 struct sock *sk = sock->sk;
643 struct netlink_sock *nlk = nlk_sk(sk);
647 if (nlk->rx_ring.pg_vec != NULL) {
648 /* Memory mapped sockets don't call recvmsg(), so flow control
649 * for dumps is performed here. A dump is allowed to continue
650 * if at least half the ring is unused.
652 while (nlk->cb_running && netlink_dump_space(nlk)) {
653 err = netlink_dump(sk);
656 sk->sk_error_report(sk);
660 netlink_rcv_wake(sk);
663 mask = datagram_poll(file, sock, wait);
665 spin_lock_bh(&sk->sk_receive_queue.lock);
666 if (nlk->rx_ring.pg_vec) {
667 netlink_forward_ring(&nlk->rx_ring);
668 if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
669 mask |= POLLIN | POLLRDNORM;
671 spin_unlock_bh(&sk->sk_receive_queue.lock);
673 spin_lock_bh(&sk->sk_write_queue.lock);
674 if (nlk->tx_ring.pg_vec) {
675 if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
676 mask |= POLLOUT | POLLWRNORM;
678 spin_unlock_bh(&sk->sk_write_queue.lock);
683 static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
685 return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
688 static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
689 struct netlink_ring *ring,
690 struct nl_mmap_hdr *hdr)
695 size = ring->frame_size - NL_MMAP_HDRLEN;
696 data = (void *)hdr + NL_MMAP_HDRLEN;
700 skb_reset_tail_pointer(skb);
701 skb->end = skb->tail + size;
704 skb->destructor = netlink_skb_destructor;
705 NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
706 NETLINK_CB(skb).sk = sk;
709 static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
710 u32 dst_portid, u32 dst_group,
711 struct sock_iocb *siocb)
713 struct netlink_sock *nlk = nlk_sk(sk);
714 struct netlink_ring *ring;
715 struct nl_mmap_hdr *hdr;
718 int err = 0, len = 0;
720 mutex_lock(&nlk->pg_vec_lock);
722 ring = &nlk->tx_ring;
723 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
728 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
730 if (!(msg->msg_flags & MSG_DONTWAIT) &&
731 atomic_read(&nlk->tx_ring.pending))
736 nm_len = ACCESS_ONCE(hdr->nm_len);
737 if (nm_len > maxlen) {
742 netlink_frame_flush_dcache(hdr, nm_len);
744 skb = alloc_skb(nm_len, GFP_KERNEL);
749 __skb_put(skb, nm_len);
750 memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, nm_len);
751 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
753 netlink_increment_head(ring);
755 NETLINK_CB(skb).portid = nlk->portid;
756 NETLINK_CB(skb).dst_group = dst_group;
757 NETLINK_CB(skb).creds = siocb->scm->creds;
759 err = security_netlink_send(sk, skb);
765 if (unlikely(dst_group)) {
766 atomic_inc(&skb->users);
767 netlink_broadcast(sk, skb, dst_portid, dst_group,
770 err = netlink_unicast(sk, skb, dst_portid,
771 msg->msg_flags & MSG_DONTWAIT);
776 } while (hdr != NULL ||
777 (!(msg->msg_flags & MSG_DONTWAIT) &&
778 atomic_read(&nlk->tx_ring.pending)));
783 mutex_unlock(&nlk->pg_vec_lock);
787 static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
789 struct nl_mmap_hdr *hdr;
791 hdr = netlink_mmap_hdr(skb);
792 hdr->nm_len = skb->len;
793 hdr->nm_group = NETLINK_CB(skb).dst_group;
794 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
795 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
796 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
797 netlink_frame_flush_dcache(hdr, hdr->nm_len);
798 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
800 NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
804 static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
806 struct netlink_sock *nlk = nlk_sk(sk);
807 struct netlink_ring *ring = &nlk->rx_ring;
808 struct nl_mmap_hdr *hdr;
810 spin_lock_bh(&sk->sk_receive_queue.lock);
811 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
813 spin_unlock_bh(&sk->sk_receive_queue.lock);
818 netlink_increment_head(ring);
819 __skb_queue_tail(&sk->sk_receive_queue, skb);
820 spin_unlock_bh(&sk->sk_receive_queue.lock);
822 hdr->nm_len = skb->len;
823 hdr->nm_group = NETLINK_CB(skb).dst_group;
824 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
825 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
826 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
827 netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
830 #else /* CONFIG_NETLINK_MMAP */
831 #define netlink_skb_is_mmaped(skb) false
832 #define netlink_rx_is_mmaped(sk) false
833 #define netlink_tx_is_mmaped(sk) false
834 #define netlink_mmap sock_no_mmap
835 #define netlink_poll datagram_poll
836 #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
837 #endif /* CONFIG_NETLINK_MMAP */
839 static void netlink_skb_destructor(struct sk_buff *skb)
841 #ifdef CONFIG_NETLINK_MMAP
842 struct nl_mmap_hdr *hdr;
843 struct netlink_ring *ring;
846 /* If a packet from the kernel to userspace was freed because of an
847 * error without being delivered to userspace, the kernel must reset
848 * the status. In the direction userspace to kernel, the status is
849 * always reset here after the packet was processed and freed.
851 if (netlink_skb_is_mmaped(skb)) {
852 hdr = netlink_mmap_hdr(skb);
853 sk = NETLINK_CB(skb).sk;
855 if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
856 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
857 ring = &nlk_sk(sk)->tx_ring;
859 if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
861 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
863 ring = &nlk_sk(sk)->rx_ring;
866 WARN_ON(atomic_read(&ring->pending) == 0);
867 atomic_dec(&ring->pending);
873 if (is_vmalloc_addr(skb->head)) {
875 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
884 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
886 WARN_ON(skb->sk != NULL);
888 skb->destructor = netlink_skb_destructor;
889 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
890 sk_mem_charge(sk, skb->truesize);
893 static void netlink_sock_destruct(struct sock *sk)
895 struct netlink_sock *nlk = nlk_sk(sk);
897 if (nlk->cb_running) {
899 nlk->cb.done(&nlk->cb);
901 module_put(nlk->cb.module);
902 kfree_skb(nlk->cb.skb);
905 skb_queue_purge(&sk->sk_receive_queue);
906 #ifdef CONFIG_NETLINK_MMAP
908 struct nl_mmap_req req;
910 memset(&req, 0, sizeof(req));
911 if (nlk->rx_ring.pg_vec)
912 netlink_set_ring(sk, &req, true, false);
913 memset(&req, 0, sizeof(req));
914 if (nlk->tx_ring.pg_vec)
915 netlink_set_ring(sk, &req, true, true);
917 #endif /* CONFIG_NETLINK_MMAP */
919 if (!sock_flag(sk, SOCK_DEAD)) {
920 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
924 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
925 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
926 WARN_ON(nlk_sk(sk)->groups);
929 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
930 * SMP. Look, when several writers sleep and reader wakes them up, all but one
931 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
932 * this, _but_ remember, it adds useless work on UP machines.
935 void netlink_table_grab(void)
936 __acquires(nl_table_lock)
940 write_lock_irq(&nl_table_lock);
942 if (atomic_read(&nl_table_users)) {
943 DECLARE_WAITQUEUE(wait, current);
945 add_wait_queue_exclusive(&nl_table_wait, &wait);
947 set_current_state(TASK_UNINTERRUPTIBLE);
948 if (atomic_read(&nl_table_users) == 0)
950 write_unlock_irq(&nl_table_lock);
952 write_lock_irq(&nl_table_lock);
955 __set_current_state(TASK_RUNNING);
956 remove_wait_queue(&nl_table_wait, &wait);
960 void netlink_table_ungrab(void)
961 __releases(nl_table_lock)
963 write_unlock_irq(&nl_table_lock);
964 wake_up(&nl_table_wait);
968 netlink_lock_table(void)
970 /* read_lock() synchronizes us to netlink_table_grab */
972 read_lock(&nl_table_lock);
973 atomic_inc(&nl_table_users);
974 read_unlock(&nl_table_lock);
978 netlink_unlock_table(void)
980 if (atomic_dec_and_test(&nl_table_users))
981 wake_up(&nl_table_wait);
984 struct netlink_compare_arg
990 static bool netlink_compare(void *ptr, void *arg)
992 struct netlink_compare_arg *x = arg;
993 struct sock *sk = ptr;
995 return nlk_sk(sk)->portid == x->portid &&
996 net_eq(sock_net(sk), x->net);
999 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
1002 struct netlink_compare_arg arg = {
1008 hash = rhashtable_hashfn(&table->hash, &portid, sizeof(portid));
1010 return rhashtable_lookup_compare(&table->hash, hash,
1011 &netlink_compare, &arg);
1014 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
1016 struct netlink_table *table = &nl_table[protocol];
1019 read_lock(&nl_table_lock);
1021 sk = __netlink_lookup(table, portid, net);
1025 read_unlock(&nl_table_lock);
1030 static const struct proto_ops netlink_ops;
1033 netlink_update_listeners(struct sock *sk)
1035 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1038 struct listeners *listeners;
1040 listeners = nl_deref_protected(tbl->listeners);
1044 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
1046 sk_for_each_bound(sk, &tbl->mc_list) {
1047 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
1048 mask |= nlk_sk(sk)->groups[i];
1050 listeners->masks[i] = mask;
1052 /* this function is only called with the netlink table "grabbed", which
1053 * makes sure updates are visible before bind or setsockopt return. */
1056 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
1058 struct netlink_table *table = &nl_table[sk->sk_protocol];
1059 int err = -EADDRINUSE;
1061 mutex_lock(&nl_sk_hash_lock);
1062 if (__netlink_lookup(table, portid, net))
1066 if (nlk_sk(sk)->portid)
1070 if (BITS_PER_LONG > 32 && unlikely(table->hash.nelems >= UINT_MAX))
1073 nlk_sk(sk)->portid = portid;
1075 rhashtable_insert(&table->hash, &nlk_sk(sk)->node);
1078 mutex_unlock(&nl_sk_hash_lock);
1082 static void netlink_remove(struct sock *sk)
1084 struct netlink_table *table;
1086 mutex_lock(&nl_sk_hash_lock);
1087 table = &nl_table[sk->sk_protocol];
1088 if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node)) {
1089 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
1092 mutex_unlock(&nl_sk_hash_lock);
1094 netlink_table_grab();
1095 if (nlk_sk(sk)->subscriptions) {
1096 __sk_del_bind_node(sk);
1097 netlink_update_listeners(sk);
1099 if (sk->sk_protocol == NETLINK_GENERIC)
1100 atomic_inc(&genl_sk_destructing_cnt);
1101 netlink_table_ungrab();
1104 static struct proto netlink_proto = {
1106 .owner = THIS_MODULE,
1107 .obj_size = sizeof(struct netlink_sock),
1110 static int __netlink_create(struct net *net, struct socket *sock,
1111 struct mutex *cb_mutex, int protocol)
1114 struct netlink_sock *nlk;
1116 sock->ops = &netlink_ops;
1118 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
1122 sock_init_data(sock, sk);
1126 nlk->cb_mutex = cb_mutex;
1128 nlk->cb_mutex = &nlk->cb_def_mutex;
1129 mutex_init(nlk->cb_mutex);
1131 init_waitqueue_head(&nlk->wait);
1132 #ifdef CONFIG_NETLINK_MMAP
1133 mutex_init(&nlk->pg_vec_lock);
1136 sk->sk_destruct = netlink_sock_destruct;
1137 sk->sk_protocol = protocol;
1141 static int netlink_create(struct net *net, struct socket *sock, int protocol,
1144 struct module *module = NULL;
1145 struct mutex *cb_mutex;
1146 struct netlink_sock *nlk;
1147 int (*bind)(struct net *net, int group);
1148 void (*unbind)(struct net *net, int group);
1151 sock->state = SS_UNCONNECTED;
1153 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1154 return -ESOCKTNOSUPPORT;
1156 if (protocol < 0 || protocol >= MAX_LINKS)
1157 return -EPROTONOSUPPORT;
1159 netlink_lock_table();
1160 #ifdef CONFIG_MODULES
1161 if (!nl_table[protocol].registered) {
1162 netlink_unlock_table();
1163 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
1164 netlink_lock_table();
1167 if (nl_table[protocol].registered &&
1168 try_module_get(nl_table[protocol].module))
1169 module = nl_table[protocol].module;
1171 err = -EPROTONOSUPPORT;
1172 cb_mutex = nl_table[protocol].cb_mutex;
1173 bind = nl_table[protocol].bind;
1174 unbind = nl_table[protocol].unbind;
1175 netlink_unlock_table();
1180 err = __netlink_create(net, sock, cb_mutex, protocol);
1185 sock_prot_inuse_add(net, &netlink_proto, 1);
1188 nlk = nlk_sk(sock->sk);
1189 nlk->module = module;
1190 nlk->netlink_bind = bind;
1191 nlk->netlink_unbind = unbind;
1200 static int netlink_release(struct socket *sock)
1202 struct sock *sk = sock->sk;
1203 struct netlink_sock *nlk;
1213 * OK. Socket is unlinked, any packets that arrive now
1217 /* must not acquire netlink_table_lock in any way again before unbind
1218 * and notifying genetlink is done as otherwise it might deadlock
1220 if (nlk->netlink_unbind) {
1223 for (i = 0; i < nlk->ngroups; i++)
1224 if (test_bit(i, nlk->groups))
1225 nlk->netlink_unbind(sock_net(sk), i + 1);
1227 if (sk->sk_protocol == NETLINK_GENERIC &&
1228 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
1229 wake_up(&genl_sk_destructing_waitq);
1232 wake_up_interruptible_all(&nlk->wait);
1234 skb_queue_purge(&sk->sk_write_queue);
1237 struct netlink_notify n = {
1238 .net = sock_net(sk),
1239 .protocol = sk->sk_protocol,
1240 .portid = nlk->portid,
1242 atomic_notifier_call_chain(&netlink_chain,
1243 NETLINK_URELEASE, &n);
1246 module_put(nlk->module);
1248 if (netlink_is_kernel(sk)) {
1249 netlink_table_grab();
1250 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
1251 if (--nl_table[sk->sk_protocol].registered == 0) {
1252 struct listeners *old;
1254 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
1255 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
1256 kfree_rcu(old, rcu);
1257 nl_table[sk->sk_protocol].module = NULL;
1258 nl_table[sk->sk_protocol].bind = NULL;
1259 nl_table[sk->sk_protocol].unbind = NULL;
1260 nl_table[sk->sk_protocol].flags = 0;
1261 nl_table[sk->sk_protocol].registered = 0;
1263 netlink_table_ungrab();
1270 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
1276 static int netlink_autobind(struct socket *sock)
1278 struct sock *sk = sock->sk;
1279 struct net *net = sock_net(sk);
1280 struct netlink_table *table = &nl_table[sk->sk_protocol];
1281 s32 portid = task_tgid_vnr(current);
1283 static s32 rover = -4097;
1287 netlink_table_grab();
1289 if (__netlink_lookup(table, portid, net)) {
1290 /* Bind collision, search negative portid values. */
1295 netlink_table_ungrab();
1299 netlink_table_ungrab();
1301 err = netlink_insert(sk, net, portid);
1302 if (err == -EADDRINUSE)
1305 /* If 2 threads race to autobind, that is fine. */
1313 * __netlink_ns_capable - General netlink message capability test
1314 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
1315 * @user_ns: The user namespace of the capability to use
1316 * @cap: The capability to use
1318 * Test to see if the opener of the socket we received the message
1319 * from had when the netlink socket was created and the sender of the
1320 * message has has the capability @cap in the user namespace @user_ns.
1322 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
1323 struct user_namespace *user_ns, int cap)
1325 return ((nsp->flags & NETLINK_SKB_DST) ||
1326 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
1327 ns_capable(user_ns, cap);
1329 EXPORT_SYMBOL(__netlink_ns_capable);
1332 * netlink_ns_capable - General netlink message capability test
1333 * @skb: socket buffer holding a netlink command from userspace
1334 * @user_ns: The user namespace of the capability to use
1335 * @cap: The capability to use
1337 * Test to see if the opener of the socket we received the message
1338 * from had when the netlink socket was created and the sender of the
1339 * message has has the capability @cap in the user namespace @user_ns.
1341 bool netlink_ns_capable(const struct sk_buff *skb,
1342 struct user_namespace *user_ns, int cap)
1344 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
1346 EXPORT_SYMBOL(netlink_ns_capable);
1349 * netlink_capable - Netlink global message capability test
1350 * @skb: socket buffer holding a netlink command from userspace
1351 * @cap: The capability to use
1353 * Test to see if the opener of the socket we received the message
1354 * from had when the netlink socket was created and the sender of the
1355 * message has has the capability @cap in all user namespaces.
1357 bool netlink_capable(const struct sk_buff *skb, int cap)
1359 return netlink_ns_capable(skb, &init_user_ns, cap);
1361 EXPORT_SYMBOL(netlink_capable);
1364 * netlink_net_capable - Netlink network namespace message capability test
1365 * @skb: socket buffer holding a netlink command from userspace
1366 * @cap: The capability to use
1368 * Test to see if the opener of the socket we received the message
1369 * from had when the netlink socket was created and the sender of the
1370 * message has has the capability @cap over the network namespace of
1371 * the socket we received the message from.
1373 bool netlink_net_capable(const struct sk_buff *skb, int cap)
1375 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
1377 EXPORT_SYMBOL(netlink_net_capable);
1379 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
1381 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
1382 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
1386 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
1388 struct netlink_sock *nlk = nlk_sk(sk);
1390 if (nlk->subscriptions && !subscriptions)
1391 __sk_del_bind_node(sk);
1392 else if (!nlk->subscriptions && subscriptions)
1393 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
1394 nlk->subscriptions = subscriptions;
1397 static int netlink_realloc_groups(struct sock *sk)
1399 struct netlink_sock *nlk = nlk_sk(sk);
1400 unsigned int groups;
1401 unsigned long *new_groups;
1404 netlink_table_grab();
1406 groups = nl_table[sk->sk_protocol].groups;
1407 if (!nl_table[sk->sk_protocol].registered) {
1412 if (nlk->ngroups >= groups)
1415 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
1416 if (new_groups == NULL) {
1420 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
1421 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
1423 nlk->groups = new_groups;
1424 nlk->ngroups = groups;
1426 netlink_table_ungrab();
1430 static void netlink_undo_bind(int group, long unsigned int groups,
1433 struct netlink_sock *nlk = nlk_sk(sk);
1436 if (!nlk->netlink_unbind)
1439 for (undo = 0; undo < group; undo++)
1440 if (test_bit(undo, &groups))
1441 nlk->netlink_unbind(sock_net(sk), undo);
1444 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1447 struct sock *sk = sock->sk;
1448 struct net *net = sock_net(sk);
1449 struct netlink_sock *nlk = nlk_sk(sk);
1450 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1452 long unsigned int groups = nladdr->nl_groups;
1454 if (addr_len < sizeof(struct sockaddr_nl))
1457 if (nladdr->nl_family != AF_NETLINK)
1460 /* Only superuser is allowed to listen multicasts */
1462 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1464 err = netlink_realloc_groups(sk);
1470 if (nladdr->nl_pid != nlk->portid)
1473 if (nlk->netlink_bind && groups) {
1476 for (group = 0; group < nlk->ngroups; group++) {
1477 if (!test_bit(group, &groups))
1479 err = nlk->netlink_bind(net, group);
1482 netlink_undo_bind(group, groups, sk);
1488 err = nladdr->nl_pid ?
1489 netlink_insert(sk, net, nladdr->nl_pid) :
1490 netlink_autobind(sock);
1492 netlink_undo_bind(nlk->ngroups, groups, sk);
1497 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1500 netlink_table_grab();
1501 netlink_update_subscriptions(sk, nlk->subscriptions +
1503 hweight32(nlk->groups[0]));
1504 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1505 netlink_update_listeners(sk);
1506 netlink_table_ungrab();
1511 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1512 int alen, int flags)
1515 struct sock *sk = sock->sk;
1516 struct netlink_sock *nlk = nlk_sk(sk);
1517 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1519 if (alen < sizeof(addr->sa_family))
1522 if (addr->sa_family == AF_UNSPEC) {
1523 sk->sk_state = NETLINK_UNCONNECTED;
1524 nlk->dst_portid = 0;
1528 if (addr->sa_family != AF_NETLINK)
1531 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1532 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1536 err = netlink_autobind(sock);
1539 sk->sk_state = NETLINK_CONNECTED;
1540 nlk->dst_portid = nladdr->nl_pid;
1541 nlk->dst_group = ffs(nladdr->nl_groups);
1547 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1548 int *addr_len, int peer)
1550 struct sock *sk = sock->sk;
1551 struct netlink_sock *nlk = nlk_sk(sk);
1552 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1554 nladdr->nl_family = AF_NETLINK;
1556 *addr_len = sizeof(*nladdr);
1559 nladdr->nl_pid = nlk->dst_portid;
1560 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1562 nladdr->nl_pid = nlk->portid;
1563 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1568 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1571 struct netlink_sock *nlk;
1573 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1575 return ERR_PTR(-ECONNREFUSED);
1577 /* Don't bother queuing skb if kernel socket has no input function */
1579 if (sock->sk_state == NETLINK_CONNECTED &&
1580 nlk->dst_portid != nlk_sk(ssk)->portid) {
1582 return ERR_PTR(-ECONNREFUSED);
1587 struct sock *netlink_getsockbyfilp(struct file *filp)
1589 struct inode *inode = file_inode(filp);
1592 if (!S_ISSOCK(inode->i_mode))
1593 return ERR_PTR(-ENOTSOCK);
1595 sock = SOCKET_I(inode)->sk;
1596 if (sock->sk_family != AF_NETLINK)
1597 return ERR_PTR(-EINVAL);
1603 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1606 struct sk_buff *skb;
1609 if (size <= NLMSG_GOODSIZE || broadcast)
1610 return alloc_skb(size, GFP_KERNEL);
1612 size = SKB_DATA_ALIGN(size) +
1613 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1615 data = vmalloc(size);
1619 skb = build_skb(data, size);
1624 skb->destructor = netlink_skb_destructor;
1631 * Attach a skb to a netlink socket.
1632 * The caller must hold a reference to the destination socket. On error, the
1633 * reference is dropped. The skb is not send to the destination, just all
1634 * all error checks are performed and memory in the queue is reserved.
1636 * < 0: error. skb freed, reference to sock dropped.
1638 * 1: repeat lookup - reference dropped while waiting for socket memory.
1640 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1641 long *timeo, struct sock *ssk)
1643 struct netlink_sock *nlk;
1647 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1648 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1649 !netlink_skb_is_mmaped(skb)) {
1650 DECLARE_WAITQUEUE(wait, current);
1652 if (!ssk || netlink_is_kernel(ssk))
1653 netlink_overrun(sk);
1659 __set_current_state(TASK_INTERRUPTIBLE);
1660 add_wait_queue(&nlk->wait, &wait);
1662 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1663 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1664 !sock_flag(sk, SOCK_DEAD))
1665 *timeo = schedule_timeout(*timeo);
1667 __set_current_state(TASK_RUNNING);
1668 remove_wait_queue(&nlk->wait, &wait);
1671 if (signal_pending(current)) {
1673 return sock_intr_errno(*timeo);
1677 netlink_skb_set_owner_r(skb, sk);
1681 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1685 netlink_deliver_tap(skb);
1687 #ifdef CONFIG_NETLINK_MMAP
1688 if (netlink_skb_is_mmaped(skb))
1689 netlink_queue_mmaped_skb(sk, skb);
1690 else if (netlink_rx_is_mmaped(sk))
1691 netlink_ring_set_copied(sk, skb);
1693 #endif /* CONFIG_NETLINK_MMAP */
1694 skb_queue_tail(&sk->sk_receive_queue, skb);
1695 sk->sk_data_ready(sk);
1699 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1701 int len = __netlink_sendskb(sk, skb);
1707 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1713 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1717 WARN_ON(skb->sk != NULL);
1718 if (netlink_skb_is_mmaped(skb))
1721 delta = skb->end - skb->tail;
1722 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1725 if (skb_shared(skb)) {
1726 struct sk_buff *nskb = skb_clone(skb, allocation);
1733 if (!pskb_expand_head(skb, 0, -delta, allocation))
1734 skb->truesize -= delta;
1739 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1743 struct netlink_sock *nlk = nlk_sk(sk);
1745 ret = -ECONNREFUSED;
1746 if (nlk->netlink_rcv != NULL) {
1748 netlink_skb_set_owner_r(skb, sk);
1749 NETLINK_CB(skb).sk = ssk;
1750 netlink_deliver_tap_kernel(sk, ssk, skb);
1751 nlk->netlink_rcv(skb);
1760 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1761 u32 portid, int nonblock)
1767 skb = netlink_trim(skb, gfp_any());
1769 timeo = sock_sndtimeo(ssk, nonblock);
1771 sk = netlink_getsockbyportid(ssk, portid);
1776 if (netlink_is_kernel(sk))
1777 return netlink_unicast_kernel(sk, skb, ssk);
1779 if (sk_filter(sk, skb)) {
1786 err = netlink_attachskb(sk, skb, &timeo, ssk);
1792 return netlink_sendskb(sk, skb);
1794 EXPORT_SYMBOL(netlink_unicast);
1796 struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
1797 u32 dst_portid, gfp_t gfp_mask)
1799 #ifdef CONFIG_NETLINK_MMAP
1800 struct sock *sk = NULL;
1801 struct sk_buff *skb;
1802 struct netlink_ring *ring;
1803 struct nl_mmap_hdr *hdr;
1804 unsigned int maxlen;
1806 sk = netlink_getsockbyportid(ssk, dst_portid);
1810 ring = &nlk_sk(sk)->rx_ring;
1811 /* fast-path without atomic ops for common case: non-mmaped receiver */
1812 if (ring->pg_vec == NULL)
1815 if (ring->frame_size - NL_MMAP_HDRLEN < size)
1818 skb = alloc_skb_head(gfp_mask);
1822 spin_lock_bh(&sk->sk_receive_queue.lock);
1823 /* check again under lock */
1824 if (ring->pg_vec == NULL)
1827 /* check again under lock */
1828 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
1832 netlink_forward_ring(ring);
1833 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
1836 netlink_ring_setup_skb(skb, sk, ring, hdr);
1837 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
1838 atomic_inc(&ring->pending);
1839 netlink_increment_head(ring);
1841 spin_unlock_bh(&sk->sk_receive_queue.lock);
1846 spin_unlock_bh(&sk->sk_receive_queue.lock);
1847 netlink_overrun(sk);
1854 spin_unlock_bh(&sk->sk_receive_queue.lock);
1859 return alloc_skb(size, gfp_mask);
1861 EXPORT_SYMBOL_GPL(netlink_alloc_skb);
1863 int netlink_has_listeners(struct sock *sk, unsigned int group)
1866 struct listeners *listeners;
1868 BUG_ON(!netlink_is_kernel(sk));
1871 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1873 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1874 res = test_bit(group - 1, listeners->masks);
1880 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1882 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1884 struct netlink_sock *nlk = nlk_sk(sk);
1886 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1887 !test_bit(NETLINK_CONGESTED, &nlk->state)) {
1888 netlink_skb_set_owner_r(skb, sk);
1889 __netlink_sendskb(sk, skb);
1890 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1895 struct netlink_broadcast_data {
1896 struct sock *exclude_sk;
1901 int delivery_failure;
1905 struct sk_buff *skb, *skb2;
1906 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1910 static void do_one_broadcast(struct sock *sk,
1911 struct netlink_broadcast_data *p)
1913 struct netlink_sock *nlk = nlk_sk(sk);
1916 if (p->exclude_sk == sk)
1919 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1920 !test_bit(p->group - 1, nlk->groups))
1923 if (!net_eq(sock_net(sk), p->net))
1927 netlink_overrun(sk);
1932 if (p->skb2 == NULL) {
1933 if (skb_shared(p->skb)) {
1934 p->skb2 = skb_clone(p->skb, p->allocation);
1936 p->skb2 = skb_get(p->skb);
1938 * skb ownership may have been set when
1939 * delivered to a previous socket.
1941 skb_orphan(p->skb2);
1944 if (p->skb2 == NULL) {
1945 netlink_overrun(sk);
1946 /* Clone failed. Notify ALL listeners. */
1948 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1949 p->delivery_failure = 1;
1950 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1953 } else if (sk_filter(sk, p->skb2)) {
1956 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1957 netlink_overrun(sk);
1958 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1959 p->delivery_failure = 1;
1961 p->congested |= val;
1968 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1969 u32 group, gfp_t allocation,
1970 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1973 struct net *net = sock_net(ssk);
1974 struct netlink_broadcast_data info;
1977 skb = netlink_trim(skb, allocation);
1979 info.exclude_sk = ssk;
1981 info.portid = portid;
1984 info.delivery_failure = 0;
1987 info.allocation = allocation;
1990 info.tx_filter = filter;
1991 info.tx_data = filter_data;
1993 /* While we sleep in clone, do not allow to change socket list */
1995 netlink_lock_table();
1997 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1998 do_one_broadcast(sk, &info);
2002 netlink_unlock_table();
2004 if (info.delivery_failure) {
2005 kfree_skb(info.skb2);
2008 consume_skb(info.skb2);
2010 if (info.delivered) {
2011 if (info.congested && (allocation & __GFP_WAIT))
2017 EXPORT_SYMBOL(netlink_broadcast_filtered);
2019 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
2020 u32 group, gfp_t allocation)
2022 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
2025 EXPORT_SYMBOL(netlink_broadcast);
2027 struct netlink_set_err_data {
2028 struct sock *exclude_sk;
2034 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
2036 struct netlink_sock *nlk = nlk_sk(sk);
2039 if (sk == p->exclude_sk)
2042 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
2045 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
2046 !test_bit(p->group - 1, nlk->groups))
2049 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
2054 sk->sk_err = p->code;
2055 sk->sk_error_report(sk);
2061 * netlink_set_err - report error to broadcast listeners
2062 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2063 * @portid: the PORTID of a process that we want to skip (if any)
2064 * @group: the broadcast group that will notice the error
2065 * @code: error code, must be negative (as usual in kernelspace)
2067 * This function returns the number of broadcast listeners that have set the
2068 * NETLINK_RECV_NO_ENOBUFS socket option.
2070 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
2072 struct netlink_set_err_data info;
2076 info.exclude_sk = ssk;
2077 info.portid = portid;
2079 /* sk->sk_err wants a positive error value */
2082 read_lock(&nl_table_lock);
2084 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2085 ret += do_one_set_err(sk, &info);
2087 read_unlock(&nl_table_lock);
2090 EXPORT_SYMBOL(netlink_set_err);
2092 /* must be called with netlink table grabbed */
2093 static void netlink_update_socket_mc(struct netlink_sock *nlk,
2097 int old, new = !!is_new, subscriptions;
2099 old = test_bit(group - 1, nlk->groups);
2100 subscriptions = nlk->subscriptions - old + new;
2102 __set_bit(group - 1, nlk->groups);
2104 __clear_bit(group - 1, nlk->groups);
2105 netlink_update_subscriptions(&nlk->sk, subscriptions);
2106 netlink_update_listeners(&nlk->sk);
2109 static int netlink_setsockopt(struct socket *sock, int level, int optname,
2110 char __user *optval, unsigned int optlen)
2112 struct sock *sk = sock->sk;
2113 struct netlink_sock *nlk = nlk_sk(sk);
2114 unsigned int val = 0;
2117 if (level != SOL_NETLINK)
2118 return -ENOPROTOOPT;
2120 if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
2121 optlen >= sizeof(int) &&
2122 get_user(val, (unsigned int __user *)optval))
2126 case NETLINK_PKTINFO:
2128 nlk->flags |= NETLINK_RECV_PKTINFO;
2130 nlk->flags &= ~NETLINK_RECV_PKTINFO;
2133 case NETLINK_ADD_MEMBERSHIP:
2134 case NETLINK_DROP_MEMBERSHIP: {
2135 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
2137 err = netlink_realloc_groups(sk);
2140 if (!val || val - 1 >= nlk->ngroups)
2142 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
2143 err = nlk->netlink_bind(sock_net(sk), val);
2147 netlink_table_grab();
2148 netlink_update_socket_mc(nlk, val,
2149 optname == NETLINK_ADD_MEMBERSHIP);
2150 netlink_table_ungrab();
2151 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
2152 nlk->netlink_unbind(sock_net(sk), val);
2157 case NETLINK_BROADCAST_ERROR:
2159 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
2161 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
2164 case NETLINK_NO_ENOBUFS:
2166 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
2167 clear_bit(NETLINK_CONGESTED, &nlk->state);
2168 wake_up_interruptible(&nlk->wait);
2170 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
2174 #ifdef CONFIG_NETLINK_MMAP
2175 case NETLINK_RX_RING:
2176 case NETLINK_TX_RING: {
2177 struct nl_mmap_req req;
2179 /* Rings might consume more memory than queue limits, require
2182 if (!capable(CAP_NET_ADMIN))
2184 if (optlen < sizeof(req))
2186 if (copy_from_user(&req, optval, sizeof(req)))
2188 err = netlink_set_ring(sk, &req, false,
2189 optname == NETLINK_TX_RING);
2192 #endif /* CONFIG_NETLINK_MMAP */
2199 static int netlink_getsockopt(struct socket *sock, int level, int optname,
2200 char __user *optval, int __user *optlen)
2202 struct sock *sk = sock->sk;
2203 struct netlink_sock *nlk = nlk_sk(sk);
2206 if (level != SOL_NETLINK)
2207 return -ENOPROTOOPT;
2209 if (get_user(len, optlen))
2215 case NETLINK_PKTINFO:
2216 if (len < sizeof(int))
2219 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
2220 if (put_user(len, optlen) ||
2221 put_user(val, optval))
2225 case NETLINK_BROADCAST_ERROR:
2226 if (len < sizeof(int))
2229 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
2230 if (put_user(len, optlen) ||
2231 put_user(val, optval))
2235 case NETLINK_NO_ENOBUFS:
2236 if (len < sizeof(int))
2239 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
2240 if (put_user(len, optlen) ||
2241 put_user(val, optval))
2251 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
2253 struct nl_pktinfo info;
2255 info.group = NETLINK_CB(skb).dst_group;
2256 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
2259 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
2260 struct msghdr *msg, size_t len)
2262 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2263 struct sock *sk = sock->sk;
2264 struct netlink_sock *nlk = nlk_sk(sk);
2265 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2268 struct sk_buff *skb;
2270 struct scm_cookie scm;
2271 u32 netlink_skb_flags = 0;
2273 if (msg->msg_flags&MSG_OOB)
2276 if (NULL == siocb->scm)
2279 err = scm_send(sock, msg, siocb->scm, true);
2283 if (msg->msg_namelen) {
2285 if (addr->nl_family != AF_NETLINK)
2287 dst_portid = addr->nl_pid;
2288 dst_group = ffs(addr->nl_groups);
2290 if ((dst_group || dst_portid) &&
2291 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
2293 netlink_skb_flags |= NETLINK_SKB_DST;
2295 dst_portid = nlk->dst_portid;
2296 dst_group = nlk->dst_group;
2300 err = netlink_autobind(sock);
2305 if (netlink_tx_is_mmaped(sk) &&
2306 msg->msg_iter.iov->iov_base == NULL) {
2307 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
2313 if (len > sk->sk_sndbuf - 32)
2316 skb = netlink_alloc_large_skb(len, dst_group);
2320 NETLINK_CB(skb).portid = nlk->portid;
2321 NETLINK_CB(skb).dst_group = dst_group;
2322 NETLINK_CB(skb).creds = siocb->scm->creds;
2323 NETLINK_CB(skb).flags = netlink_skb_flags;
2326 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
2331 err = security_netlink_send(sk, skb);
2338 atomic_inc(&skb->users);
2339 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
2341 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
2344 scm_destroy(siocb->scm);
2348 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
2349 struct msghdr *msg, size_t len,
2352 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2353 struct scm_cookie scm;
2354 struct sock *sk = sock->sk;
2355 struct netlink_sock *nlk = nlk_sk(sk);
2356 int noblock = flags&MSG_DONTWAIT;
2358 struct sk_buff *skb, *data_skb;
2366 skb = skb_recv_datagram(sk, flags, noblock, &err);
2372 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2373 if (unlikely(skb_shinfo(skb)->frag_list)) {
2375 * If this skb has a frag_list, then here that means that we
2376 * will have to use the frag_list skb's data for compat tasks
2377 * and the regular skb's data for normal (non-compat) tasks.
2379 * If we need to send the compat skb, assign it to the
2380 * 'data_skb' variable so that it will be used below for data
2381 * copying. We keep 'skb' for everything else, including
2382 * freeing both later.
2384 if (flags & MSG_CMSG_COMPAT)
2385 data_skb = skb_shinfo(skb)->frag_list;
2389 /* Record the max length of recvmsg() calls for future allocations */
2390 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
2391 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
2394 copied = data_skb->len;
2396 msg->msg_flags |= MSG_TRUNC;
2400 skb_reset_transport_header(data_skb);
2401 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
2403 if (msg->msg_name) {
2404 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2405 addr->nl_family = AF_NETLINK;
2407 addr->nl_pid = NETLINK_CB(skb).portid;
2408 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2409 msg->msg_namelen = sizeof(*addr);
2412 if (nlk->flags & NETLINK_RECV_PKTINFO)
2413 netlink_cmsg_recv_pktinfo(msg, skb);
2415 if (NULL == siocb->scm) {
2416 memset(&scm, 0, sizeof(scm));
2419 siocb->scm->creds = *NETLINK_CREDS(skb);
2420 if (flags & MSG_TRUNC)
2421 copied = data_skb->len;
2423 skb_free_datagram(sk, skb);
2425 if (nlk->cb_running &&
2426 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2427 ret = netlink_dump(sk);
2430 sk->sk_error_report(sk);
2434 scm_recv(sock, msg, siocb->scm, flags);
2436 netlink_rcv_wake(sk);
2437 return err ? : copied;
2440 static void netlink_data_ready(struct sock *sk)
2446 * We export these functions to other modules. They provide a
2447 * complete set of kernel non-blocking support for message
2452 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2453 struct netlink_kernel_cfg *cfg)
2455 struct socket *sock;
2457 struct netlink_sock *nlk;
2458 struct listeners *listeners = NULL;
2459 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2460 unsigned int groups;
2464 if (unit < 0 || unit >= MAX_LINKS)
2467 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2471 * We have to just have a reference on the net from sk, but don't
2472 * get_net it. Besides, we cannot get and then put the net here.
2473 * So we create one inside init_net and the move it to net.
2476 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
2477 goto out_sock_release_nosk;
2480 sk_change_net(sk, net);
2482 if (!cfg || cfg->groups < 32)
2485 groups = cfg->groups;
2487 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2489 goto out_sock_release;
2491 sk->sk_data_ready = netlink_data_ready;
2492 if (cfg && cfg->input)
2493 nlk_sk(sk)->netlink_rcv = cfg->input;
2495 if (netlink_insert(sk, net, 0))
2496 goto out_sock_release;
2499 nlk->flags |= NETLINK_KERNEL_SOCKET;
2501 netlink_table_grab();
2502 if (!nl_table[unit].registered) {
2503 nl_table[unit].groups = groups;
2504 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2505 nl_table[unit].cb_mutex = cb_mutex;
2506 nl_table[unit].module = module;
2508 nl_table[unit].bind = cfg->bind;
2509 nl_table[unit].unbind = cfg->unbind;
2510 nl_table[unit].flags = cfg->flags;
2512 nl_table[unit].compare = cfg->compare;
2514 nl_table[unit].registered = 1;
2517 nl_table[unit].registered++;
2519 netlink_table_ungrab();
2524 netlink_kernel_release(sk);
2527 out_sock_release_nosk:
2531 EXPORT_SYMBOL(__netlink_kernel_create);
2534 netlink_kernel_release(struct sock *sk)
2536 sk_release_kernel(sk);
2538 EXPORT_SYMBOL(netlink_kernel_release);
2540 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2542 struct listeners *new, *old;
2543 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2548 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2549 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2552 old = nl_deref_protected(tbl->listeners);
2553 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2554 rcu_assign_pointer(tbl->listeners, new);
2556 kfree_rcu(old, rcu);
2558 tbl->groups = groups;
2564 * netlink_change_ngroups - change number of multicast groups
2566 * This changes the number of multicast groups that are available
2567 * on a certain netlink family. Note that it is not possible to
2568 * change the number of groups to below 32. Also note that it does
2569 * not implicitly call netlink_clear_multicast_users() when the
2570 * number of groups is reduced.
2572 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2573 * @groups: The new number of groups.
2575 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2579 netlink_table_grab();
2580 err = __netlink_change_ngroups(sk, groups);
2581 netlink_table_ungrab();
2586 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2589 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2591 sk_for_each_bound(sk, &tbl->mc_list)
2592 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2596 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2598 struct nlmsghdr *nlh;
2599 int size = nlmsg_msg_size(len);
2601 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2602 nlh->nlmsg_type = type;
2603 nlh->nlmsg_len = size;
2604 nlh->nlmsg_flags = flags;
2605 nlh->nlmsg_pid = portid;
2606 nlh->nlmsg_seq = seq;
2607 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2608 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2611 EXPORT_SYMBOL(__nlmsg_put);
2614 * It looks a bit ugly.
2615 * It would be better to create kernel thread.
2618 static int netlink_dump(struct sock *sk)
2620 struct netlink_sock *nlk = nlk_sk(sk);
2621 struct netlink_callback *cb;
2622 struct sk_buff *skb = NULL;
2623 struct nlmsghdr *nlh;
2624 int len, err = -ENOBUFS;
2627 mutex_lock(nlk->cb_mutex);
2628 if (!nlk->cb_running) {
2634 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2636 if (!netlink_rx_is_mmaped(sk) &&
2637 atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2640 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2641 * required, but it makes sense to _attempt_ a 16K bytes allocation
2642 * to reduce number of system calls on dump operations, if user
2643 * ever provided a big enough buffer.
2645 if (alloc_size < nlk->max_recvmsg_len) {
2646 skb = netlink_alloc_skb(sk,
2647 nlk->max_recvmsg_len,
2652 /* available room should be exact amount to avoid MSG_TRUNC */
2654 skb_reserve(skb, skb_tailroom(skb) -
2655 nlk->max_recvmsg_len);
2658 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2662 netlink_skb_set_owner_r(skb, sk);
2664 len = cb->dump(skb, cb);
2667 mutex_unlock(nlk->cb_mutex);
2669 if (sk_filter(sk, skb))
2672 __netlink_sendskb(sk, skb);
2676 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2680 nl_dump_check_consistent(cb, nlh);
2682 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2684 if (sk_filter(sk, skb))
2687 __netlink_sendskb(sk, skb);
2692 nlk->cb_running = false;
2693 mutex_unlock(nlk->cb_mutex);
2694 module_put(cb->module);
2695 consume_skb(cb->skb);
2699 mutex_unlock(nlk->cb_mutex);
2704 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2705 const struct nlmsghdr *nlh,
2706 struct netlink_dump_control *control)
2708 struct netlink_callback *cb;
2710 struct netlink_sock *nlk;
2713 /* Memory mapped dump requests need to be copied to avoid looping
2714 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2715 * a reference to the skb.
2717 if (netlink_skb_is_mmaped(skb)) {
2718 skb = skb_copy(skb, GFP_KERNEL);
2722 atomic_inc(&skb->users);
2724 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2726 ret = -ECONNREFUSED;
2731 mutex_lock(nlk->cb_mutex);
2732 /* A dump is in progress... */
2733 if (nlk->cb_running) {
2737 /* add reference of module which cb->dump belongs to */
2738 if (!try_module_get(control->module)) {
2739 ret = -EPROTONOSUPPORT;
2744 memset(cb, 0, sizeof(*cb));
2745 cb->dump = control->dump;
2746 cb->done = control->done;
2748 cb->data = control->data;
2749 cb->module = control->module;
2750 cb->min_dump_alloc = control->min_dump_alloc;
2753 nlk->cb_running = true;
2755 mutex_unlock(nlk->cb_mutex);
2757 ret = netlink_dump(sk);
2763 /* We successfully started a dump, by returning -EINTR we
2764 * signal not to send ACK even if it was requested.
2770 mutex_unlock(nlk->cb_mutex);
2775 EXPORT_SYMBOL(__netlink_dump_start);
2777 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2779 struct sk_buff *skb;
2780 struct nlmsghdr *rep;
2781 struct nlmsgerr *errmsg;
2782 size_t payload = sizeof(*errmsg);
2784 /* error messages get the original request appened */
2786 payload += nlmsg_len(nlh);
2788 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2789 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2793 sk = netlink_lookup(sock_net(in_skb->sk),
2794 in_skb->sk->sk_protocol,
2795 NETLINK_CB(in_skb).portid);
2797 sk->sk_err = ENOBUFS;
2798 sk->sk_error_report(sk);
2804 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2805 NLMSG_ERROR, payload, 0);
2806 errmsg = nlmsg_data(rep);
2807 errmsg->error = err;
2808 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
2809 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2811 EXPORT_SYMBOL(netlink_ack);
2813 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2816 struct nlmsghdr *nlh;
2819 while (skb->len >= nlmsg_total_size(0)) {
2822 nlh = nlmsg_hdr(skb);
2825 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2828 /* Only requests are handled by the kernel */
2829 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2832 /* Skip control messages */
2833 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2841 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2842 netlink_ack(skb, nlh, err);
2845 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2846 if (msglen > skb->len)
2848 skb_pull(skb, msglen);
2853 EXPORT_SYMBOL(netlink_rcv_skb);
2856 * nlmsg_notify - send a notification netlink message
2857 * @sk: netlink socket to use
2858 * @skb: notification message
2859 * @portid: destination netlink portid for reports or 0
2860 * @group: destination multicast group or 0
2861 * @report: 1 to report back, 0 to disable
2862 * @flags: allocation flags
2864 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2865 unsigned int group, int report, gfp_t flags)
2870 int exclude_portid = 0;
2873 atomic_inc(&skb->users);
2874 exclude_portid = portid;
2877 /* errors reported via destination sk->sk_err, but propagate
2878 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2879 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2885 err2 = nlmsg_unicast(sk, skb, portid);
2886 if (!err || err == -ESRCH)
2892 EXPORT_SYMBOL(nlmsg_notify);
2894 #ifdef CONFIG_PROC_FS
2895 struct nl_seq_iter {
2896 struct seq_net_private p;
2901 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
2903 struct nl_seq_iter *iter = seq->private;
2905 struct netlink_sock *nlk;
2909 for (i = 0; i < MAX_LINKS; i++) {
2910 struct rhashtable *ht = &nl_table[i].hash;
2911 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2913 for (j = 0; j < tbl->size; j++) {
2914 rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
2915 s = (struct sock *)nlk;
2917 if (sock_net(s) != seq_file_net(seq))
2931 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2932 __acquires(nl_table_lock) __acquires(RCU)
2934 read_lock(&nl_table_lock);
2936 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2939 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2941 struct rhashtable *ht;
2942 struct netlink_sock *nlk;
2943 struct nl_seq_iter *iter;
2949 if (v == SEQ_START_TOKEN)
2950 return netlink_seq_socket_idx(seq, 0);
2952 net = seq_file_net(seq);
2953 iter = seq->private;
2957 ht = &nl_table[i].hash;
2958 rht_for_each_entry(nlk, nlk->node.next, ht, node)
2959 if (net_eq(sock_net((struct sock *)nlk), net))
2962 j = iter->hash_idx + 1;
2965 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2967 for (; j < tbl->size; j++) {
2968 rht_for_each_entry(nlk, tbl->buckets[j], ht, node) {
2969 if (net_eq(sock_net((struct sock *)nlk), net)) {
2978 } while (++i < MAX_LINKS);
2983 static void netlink_seq_stop(struct seq_file *seq, void *v)
2984 __releases(RCU) __releases(nl_table_lock)
2987 read_unlock(&nl_table_lock);
2991 static int netlink_seq_show(struct seq_file *seq, void *v)
2993 if (v == SEQ_START_TOKEN) {
2995 "sk Eth Pid Groups "
2996 "Rmem Wmem Dump Locks Drops Inode\n");
2999 struct netlink_sock *nlk = nlk_sk(s);
3001 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
3005 nlk->groups ? (u32)nlk->groups[0] : 0,
3006 sk_rmem_alloc_get(s),
3007 sk_wmem_alloc_get(s),
3009 atomic_read(&s->sk_refcnt),
3010 atomic_read(&s->sk_drops),
3018 static const struct seq_operations netlink_seq_ops = {
3019 .start = netlink_seq_start,
3020 .next = netlink_seq_next,
3021 .stop = netlink_seq_stop,
3022 .show = netlink_seq_show,
3026 static int netlink_seq_open(struct inode *inode, struct file *file)
3028 return seq_open_net(inode, file, &netlink_seq_ops,
3029 sizeof(struct nl_seq_iter));
3032 static const struct file_operations netlink_seq_fops = {
3033 .owner = THIS_MODULE,
3034 .open = netlink_seq_open,
3036 .llseek = seq_lseek,
3037 .release = seq_release_net,
3042 int netlink_register_notifier(struct notifier_block *nb)
3044 return atomic_notifier_chain_register(&netlink_chain, nb);
3046 EXPORT_SYMBOL(netlink_register_notifier);
3048 int netlink_unregister_notifier(struct notifier_block *nb)
3050 return atomic_notifier_chain_unregister(&netlink_chain, nb);
3052 EXPORT_SYMBOL(netlink_unregister_notifier);
3054 static const struct proto_ops netlink_ops = {
3055 .family = PF_NETLINK,
3056 .owner = THIS_MODULE,
3057 .release = netlink_release,
3058 .bind = netlink_bind,
3059 .connect = netlink_connect,
3060 .socketpair = sock_no_socketpair,
3061 .accept = sock_no_accept,
3062 .getname = netlink_getname,
3063 .poll = netlink_poll,
3064 .ioctl = sock_no_ioctl,
3065 .listen = sock_no_listen,
3066 .shutdown = sock_no_shutdown,
3067 .setsockopt = netlink_setsockopt,
3068 .getsockopt = netlink_getsockopt,
3069 .sendmsg = netlink_sendmsg,
3070 .recvmsg = netlink_recvmsg,
3071 .mmap = netlink_mmap,
3072 .sendpage = sock_no_sendpage,
3075 static const struct net_proto_family netlink_family_ops = {
3076 .family = PF_NETLINK,
3077 .create = netlink_create,
3078 .owner = THIS_MODULE, /* for consistency 8) */
3081 static int __net_init netlink_net_init(struct net *net)
3083 #ifdef CONFIG_PROC_FS
3084 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
3090 static void __net_exit netlink_net_exit(struct net *net)
3092 #ifdef CONFIG_PROC_FS
3093 remove_proc_entry("netlink", net->proc_net);
3097 static void __init netlink_add_usersock_entry(void)
3099 struct listeners *listeners;
3102 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
3104 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3106 netlink_table_grab();
3108 nl_table[NETLINK_USERSOCK].groups = groups;
3109 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
3110 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
3111 nl_table[NETLINK_USERSOCK].registered = 1;
3112 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
3114 netlink_table_ungrab();
3117 static struct pernet_operations __net_initdata netlink_net_ops = {
3118 .init = netlink_net_init,
3119 .exit = netlink_net_exit,
3122 static int __init netlink_proto_init(void)
3125 int err = proto_register(&netlink_proto, 0);
3126 struct rhashtable_params ht_params = {
3127 .head_offset = offsetof(struct netlink_sock, node),
3128 .key_offset = offsetof(struct netlink_sock, portid),
3129 .key_len = sizeof(u32), /* portid */
3131 .max_shift = 16, /* 64K */
3132 .grow_decision = rht_grow_above_75,
3133 .shrink_decision = rht_shrink_below_30,
3134 #ifdef CONFIG_PROVE_LOCKING
3135 .mutex_is_held = lockdep_nl_sk_hash_is_held,
3142 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
3144 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
3148 for (i = 0; i < MAX_LINKS; i++) {
3149 if (rhashtable_init(&nl_table[i].hash, &ht_params) < 0) {
3151 rhashtable_destroy(&nl_table[i].hash);
3157 INIT_LIST_HEAD(&netlink_tap_all);
3159 netlink_add_usersock_entry();
3161 sock_register(&netlink_family_ops);
3162 register_pernet_subsys(&netlink_net_ops);
3163 /* The netlink device handler may be needed early. */
3168 panic("netlink_init: Cannot allocate nl_table\n");
3171 core_initcall(netlink_proto_init);