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>
65 #include <net/net_namespace.h>
68 #include <net/netlink.h>
70 #include "af_netlink.h"
74 unsigned long masks[0];
78 #define NETLINK_CONGESTED 0x0
81 #define NETLINK_KERNEL_SOCKET 0x1
82 #define NETLINK_RECV_PKTINFO 0x2
83 #define NETLINK_BROADCAST_SEND_ERROR 0x4
84 #define NETLINK_RECV_NO_ENOBUFS 0x8
86 static inline int netlink_is_kernel(struct sock *sk)
88 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
91 struct netlink_table *nl_table;
92 EXPORT_SYMBOL_GPL(nl_table);
94 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
96 static int netlink_dump(struct sock *sk);
97 static void netlink_skb_destructor(struct sk_buff *skb);
99 DEFINE_RWLOCK(nl_table_lock);
100 EXPORT_SYMBOL_GPL(nl_table_lock);
101 static atomic_t nl_table_users = ATOMIC_INIT(0);
103 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
105 /* Protects netlink socket hash table mutations */
106 DEFINE_MUTEX(nl_sk_hash_lock);
108 static int lockdep_nl_sk_hash_is_held(void)
110 #ifdef CONFIG_LOCKDEP
111 return (debug_locks) ? lockdep_is_held(&nl_sk_hash_lock) : 1;
117 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
119 static DEFINE_SPINLOCK(netlink_tap_lock);
120 static struct list_head netlink_tap_all __read_mostly;
122 static inline u32 netlink_group_mask(u32 group)
124 return group ? 1 << (group - 1) : 0;
127 int netlink_add_tap(struct netlink_tap *nt)
129 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
132 spin_lock(&netlink_tap_lock);
133 list_add_rcu(&nt->list, &netlink_tap_all);
134 spin_unlock(&netlink_tap_lock);
137 __module_get(nt->module);
141 EXPORT_SYMBOL_GPL(netlink_add_tap);
143 static int __netlink_remove_tap(struct netlink_tap *nt)
146 struct netlink_tap *tmp;
148 spin_lock(&netlink_tap_lock);
150 list_for_each_entry(tmp, &netlink_tap_all, list) {
152 list_del_rcu(&nt->list);
158 pr_warn("__netlink_remove_tap: %p not found\n", nt);
160 spin_unlock(&netlink_tap_lock);
162 if (found && nt->module)
163 module_put(nt->module);
165 return found ? 0 : -ENODEV;
168 int netlink_remove_tap(struct netlink_tap *nt)
172 ret = __netlink_remove_tap(nt);
177 EXPORT_SYMBOL_GPL(netlink_remove_tap);
179 static bool netlink_filter_tap(const struct sk_buff *skb)
181 struct sock *sk = skb->sk;
183 /* We take the more conservative approach and
184 * whitelist socket protocols that may pass.
186 switch (sk->sk_protocol) {
188 case NETLINK_USERSOCK:
189 case NETLINK_SOCK_DIAG:
192 case NETLINK_FIB_LOOKUP:
193 case NETLINK_NETFILTER:
194 case NETLINK_GENERIC:
201 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
202 struct net_device *dev)
204 struct sk_buff *nskb;
205 struct sock *sk = skb->sk;
209 nskb = skb_clone(skb, GFP_ATOMIC);
212 nskb->protocol = htons((u16) sk->sk_protocol);
213 nskb->pkt_type = netlink_is_kernel(sk) ?
214 PACKET_KERNEL : PACKET_USER;
216 ret = dev_queue_xmit(nskb);
217 if (unlikely(ret > 0))
218 ret = net_xmit_errno(ret);
225 static void __netlink_deliver_tap(struct sk_buff *skb)
228 struct netlink_tap *tmp;
230 if (!netlink_filter_tap(skb))
233 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
234 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
240 static void netlink_deliver_tap(struct sk_buff *skb)
244 if (unlikely(!list_empty(&netlink_tap_all)))
245 __netlink_deliver_tap(skb);
250 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
253 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
254 netlink_deliver_tap(skb);
257 static void netlink_overrun(struct sock *sk)
259 struct netlink_sock *nlk = nlk_sk(sk);
261 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
262 if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
263 sk->sk_err = ENOBUFS;
264 sk->sk_error_report(sk);
267 atomic_inc(&sk->sk_drops);
270 static void netlink_rcv_wake(struct sock *sk)
272 struct netlink_sock *nlk = nlk_sk(sk);
274 if (skb_queue_empty(&sk->sk_receive_queue))
275 clear_bit(NETLINK_CONGESTED, &nlk->state);
276 if (!test_bit(NETLINK_CONGESTED, &nlk->state))
277 wake_up_interruptible(&nlk->wait);
280 #ifdef CONFIG_NETLINK_MMAP
281 static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
283 return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
286 static bool netlink_rx_is_mmaped(struct sock *sk)
288 return nlk_sk(sk)->rx_ring.pg_vec != NULL;
291 static bool netlink_tx_is_mmaped(struct sock *sk)
293 return nlk_sk(sk)->tx_ring.pg_vec != NULL;
296 static __pure struct page *pgvec_to_page(const void *addr)
298 if (is_vmalloc_addr(addr))
299 return vmalloc_to_page(addr);
301 return virt_to_page(addr);
304 static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
308 for (i = 0; i < len; i++) {
309 if (pg_vec[i] != NULL) {
310 if (is_vmalloc_addr(pg_vec[i]))
313 free_pages((unsigned long)pg_vec[i], order);
319 static void *alloc_one_pg_vec_page(unsigned long order)
322 gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
323 __GFP_NOWARN | __GFP_NORETRY;
325 buffer = (void *)__get_free_pages(gfp_flags, order);
329 buffer = vzalloc((1 << order) * PAGE_SIZE);
333 gfp_flags &= ~__GFP_NORETRY;
334 return (void *)__get_free_pages(gfp_flags, order);
337 static void **alloc_pg_vec(struct netlink_sock *nlk,
338 struct nl_mmap_req *req, unsigned int order)
340 unsigned int block_nr = req->nm_block_nr;
344 pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
348 for (i = 0; i < block_nr; i++) {
349 pg_vec[i] = alloc_one_pg_vec_page(order);
350 if (pg_vec[i] == NULL)
356 free_pg_vec(pg_vec, order, block_nr);
360 static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
361 bool closing, bool tx_ring)
363 struct netlink_sock *nlk = nlk_sk(sk);
364 struct netlink_ring *ring;
365 struct sk_buff_head *queue;
366 void **pg_vec = NULL;
367 unsigned int order = 0;
370 ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
371 queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
374 if (atomic_read(&nlk->mapped))
376 if (atomic_read(&ring->pending))
380 if (req->nm_block_nr) {
381 if (ring->pg_vec != NULL)
384 if ((int)req->nm_block_size <= 0)
386 if (!PAGE_ALIGNED(req->nm_block_size))
388 if (req->nm_frame_size < NL_MMAP_HDRLEN)
390 if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
393 ring->frames_per_block = req->nm_block_size /
395 if (ring->frames_per_block == 0)
397 if (ring->frames_per_block * req->nm_block_nr !=
401 order = get_order(req->nm_block_size);
402 pg_vec = alloc_pg_vec(nlk, req, order);
406 if (req->nm_frame_nr)
411 mutex_lock(&nlk->pg_vec_lock);
412 if (closing || atomic_read(&nlk->mapped) == 0) {
414 spin_lock_bh(&queue->lock);
416 ring->frame_max = req->nm_frame_nr - 1;
418 ring->frame_size = req->nm_frame_size;
419 ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
421 swap(ring->pg_vec_len, req->nm_block_nr);
422 swap(ring->pg_vec_order, order);
423 swap(ring->pg_vec, pg_vec);
425 __skb_queue_purge(queue);
426 spin_unlock_bh(&queue->lock);
428 WARN_ON(atomic_read(&nlk->mapped));
430 mutex_unlock(&nlk->pg_vec_lock);
433 free_pg_vec(pg_vec, order, req->nm_block_nr);
437 static void netlink_mm_open(struct vm_area_struct *vma)
439 struct file *file = vma->vm_file;
440 struct socket *sock = file->private_data;
441 struct sock *sk = sock->sk;
444 atomic_inc(&nlk_sk(sk)->mapped);
447 static void netlink_mm_close(struct vm_area_struct *vma)
449 struct file *file = vma->vm_file;
450 struct socket *sock = file->private_data;
451 struct sock *sk = sock->sk;
454 atomic_dec(&nlk_sk(sk)->mapped);
457 static const struct vm_operations_struct netlink_mmap_ops = {
458 .open = netlink_mm_open,
459 .close = netlink_mm_close,
462 static int netlink_mmap(struct file *file, struct socket *sock,
463 struct vm_area_struct *vma)
465 struct sock *sk = sock->sk;
466 struct netlink_sock *nlk = nlk_sk(sk);
467 struct netlink_ring *ring;
468 unsigned long start, size, expected;
475 mutex_lock(&nlk->pg_vec_lock);
478 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
479 if (ring->pg_vec == NULL)
481 expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
487 size = vma->vm_end - vma->vm_start;
488 if (size != expected)
491 start = vma->vm_start;
492 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
493 if (ring->pg_vec == NULL)
496 for (i = 0; i < ring->pg_vec_len; i++) {
498 void *kaddr = ring->pg_vec[i];
501 for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
502 page = pgvec_to_page(kaddr);
503 err = vm_insert_page(vma, start, page);
512 atomic_inc(&nlk->mapped);
513 vma->vm_ops = &netlink_mmap_ops;
516 mutex_unlock(&nlk->pg_vec_lock);
520 static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
522 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
523 struct page *p_start, *p_end;
525 /* First page is flushed through netlink_{get,set}_status */
526 p_start = pgvec_to_page(hdr + PAGE_SIZE);
527 p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
528 while (p_start <= p_end) {
529 flush_dcache_page(p_start);
535 static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
538 flush_dcache_page(pgvec_to_page(hdr));
539 return hdr->nm_status;
542 static void netlink_set_status(struct nl_mmap_hdr *hdr,
543 enum nl_mmap_status status)
545 hdr->nm_status = status;
546 flush_dcache_page(pgvec_to_page(hdr));
550 static struct nl_mmap_hdr *
551 __netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
553 unsigned int pg_vec_pos, frame_off;
555 pg_vec_pos = pos / ring->frames_per_block;
556 frame_off = pos % ring->frames_per_block;
558 return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
561 static struct nl_mmap_hdr *
562 netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
563 enum nl_mmap_status status)
565 struct nl_mmap_hdr *hdr;
567 hdr = __netlink_lookup_frame(ring, pos);
568 if (netlink_get_status(hdr) != status)
574 static struct nl_mmap_hdr *
575 netlink_current_frame(const struct netlink_ring *ring,
576 enum nl_mmap_status status)
578 return netlink_lookup_frame(ring, ring->head, status);
581 static struct nl_mmap_hdr *
582 netlink_previous_frame(const struct netlink_ring *ring,
583 enum nl_mmap_status status)
587 prev = ring->head ? ring->head - 1 : ring->frame_max;
588 return netlink_lookup_frame(ring, prev, status);
591 static void netlink_increment_head(struct netlink_ring *ring)
593 ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
596 static void netlink_forward_ring(struct netlink_ring *ring)
598 unsigned int head = ring->head, pos = head;
599 const struct nl_mmap_hdr *hdr;
602 hdr = __netlink_lookup_frame(ring, pos);
603 if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
605 if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
607 netlink_increment_head(ring);
608 } while (ring->head != head);
611 static bool netlink_dump_space(struct netlink_sock *nlk)
613 struct netlink_ring *ring = &nlk->rx_ring;
614 struct nl_mmap_hdr *hdr;
617 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
621 n = ring->head + ring->frame_max / 2;
622 if (n > ring->frame_max)
623 n -= ring->frame_max;
625 hdr = __netlink_lookup_frame(ring, n);
627 return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
630 static unsigned int netlink_poll(struct file *file, struct socket *sock,
633 struct sock *sk = sock->sk;
634 struct netlink_sock *nlk = nlk_sk(sk);
638 if (nlk->rx_ring.pg_vec != NULL) {
639 /* Memory mapped sockets don't call recvmsg(), so flow control
640 * for dumps is performed here. A dump is allowed to continue
641 * if at least half the ring is unused.
643 while (nlk->cb_running && netlink_dump_space(nlk)) {
644 err = netlink_dump(sk);
647 sk->sk_error_report(sk);
651 netlink_rcv_wake(sk);
654 mask = datagram_poll(file, sock, wait);
656 spin_lock_bh(&sk->sk_receive_queue.lock);
657 if (nlk->rx_ring.pg_vec) {
658 netlink_forward_ring(&nlk->rx_ring);
659 if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
660 mask |= POLLIN | POLLRDNORM;
662 spin_unlock_bh(&sk->sk_receive_queue.lock);
664 spin_lock_bh(&sk->sk_write_queue.lock);
665 if (nlk->tx_ring.pg_vec) {
666 if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
667 mask |= POLLOUT | POLLWRNORM;
669 spin_unlock_bh(&sk->sk_write_queue.lock);
674 static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
676 return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
679 static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
680 struct netlink_ring *ring,
681 struct nl_mmap_hdr *hdr)
686 size = ring->frame_size - NL_MMAP_HDRLEN;
687 data = (void *)hdr + NL_MMAP_HDRLEN;
691 skb_reset_tail_pointer(skb);
692 skb->end = skb->tail + size;
695 skb->destructor = netlink_skb_destructor;
696 NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
697 NETLINK_CB(skb).sk = sk;
700 static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
701 u32 dst_portid, u32 dst_group,
702 struct sock_iocb *siocb)
704 struct netlink_sock *nlk = nlk_sk(sk);
705 struct netlink_ring *ring;
706 struct nl_mmap_hdr *hdr;
710 int err = 0, len = 0;
712 /* Netlink messages are validated by the receiver before processing.
713 * In order to avoid userspace changing the contents of the message
714 * after validation, the socket and the ring may only be used by a
715 * single process, otherwise we fall back to copying.
717 if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
718 atomic_read(&nlk->mapped) > 1)
721 mutex_lock(&nlk->pg_vec_lock);
723 ring = &nlk->tx_ring;
724 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
727 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
729 if (!(msg->msg_flags & MSG_DONTWAIT) &&
730 atomic_read(&nlk->tx_ring.pending))
734 if (hdr->nm_len > maxlen) {
739 netlink_frame_flush_dcache(hdr);
741 if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
742 skb = alloc_skb_head(GFP_KERNEL);
748 netlink_ring_setup_skb(skb, sk, ring, hdr);
749 NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
750 __skb_put(skb, hdr->nm_len);
751 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
752 atomic_inc(&ring->pending);
754 skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
759 __skb_put(skb, hdr->nm_len);
760 memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
761 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
764 netlink_increment_head(ring);
766 NETLINK_CB(skb).portid = nlk->portid;
767 NETLINK_CB(skb).dst_group = dst_group;
768 NETLINK_CB(skb).creds = siocb->scm->creds;
770 err = security_netlink_send(sk, skb);
776 if (unlikely(dst_group)) {
777 atomic_inc(&skb->users);
778 netlink_broadcast(sk, skb, dst_portid, dst_group,
781 err = netlink_unicast(sk, skb, dst_portid,
782 msg->msg_flags & MSG_DONTWAIT);
787 } while (hdr != NULL ||
788 (!(msg->msg_flags & MSG_DONTWAIT) &&
789 atomic_read(&nlk->tx_ring.pending)));
794 mutex_unlock(&nlk->pg_vec_lock);
798 static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
800 struct nl_mmap_hdr *hdr;
802 hdr = netlink_mmap_hdr(skb);
803 hdr->nm_len = skb->len;
804 hdr->nm_group = NETLINK_CB(skb).dst_group;
805 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
806 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
807 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
808 netlink_frame_flush_dcache(hdr);
809 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
811 NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
815 static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
817 struct netlink_sock *nlk = nlk_sk(sk);
818 struct netlink_ring *ring = &nlk->rx_ring;
819 struct nl_mmap_hdr *hdr;
821 spin_lock_bh(&sk->sk_receive_queue.lock);
822 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
824 spin_unlock_bh(&sk->sk_receive_queue.lock);
829 netlink_increment_head(ring);
830 __skb_queue_tail(&sk->sk_receive_queue, skb);
831 spin_unlock_bh(&sk->sk_receive_queue.lock);
833 hdr->nm_len = skb->len;
834 hdr->nm_group = NETLINK_CB(skb).dst_group;
835 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
836 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
837 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
838 netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
841 #else /* CONFIG_NETLINK_MMAP */
842 #define netlink_skb_is_mmaped(skb) false
843 #define netlink_rx_is_mmaped(sk) false
844 #define netlink_tx_is_mmaped(sk) false
845 #define netlink_mmap sock_no_mmap
846 #define netlink_poll datagram_poll
847 #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
848 #endif /* CONFIG_NETLINK_MMAP */
850 static void netlink_skb_destructor(struct sk_buff *skb)
852 #ifdef CONFIG_NETLINK_MMAP
853 struct nl_mmap_hdr *hdr;
854 struct netlink_ring *ring;
857 /* If a packet from the kernel to userspace was freed because of an
858 * error without being delivered to userspace, the kernel must reset
859 * the status. In the direction userspace to kernel, the status is
860 * always reset here after the packet was processed and freed.
862 if (netlink_skb_is_mmaped(skb)) {
863 hdr = netlink_mmap_hdr(skb);
864 sk = NETLINK_CB(skb).sk;
866 if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
867 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
868 ring = &nlk_sk(sk)->tx_ring;
870 if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
872 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
874 ring = &nlk_sk(sk)->rx_ring;
877 WARN_ON(atomic_read(&ring->pending) == 0);
878 atomic_dec(&ring->pending);
884 if (is_vmalloc_addr(skb->head)) {
886 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
895 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
897 WARN_ON(skb->sk != NULL);
899 skb->destructor = netlink_skb_destructor;
900 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
901 sk_mem_charge(sk, skb->truesize);
904 static void netlink_sock_destruct(struct sock *sk)
906 struct netlink_sock *nlk = nlk_sk(sk);
908 if (nlk->cb_running) {
910 nlk->cb.done(&nlk->cb);
912 module_put(nlk->cb.module);
913 kfree_skb(nlk->cb.skb);
916 skb_queue_purge(&sk->sk_receive_queue);
917 #ifdef CONFIG_NETLINK_MMAP
919 struct nl_mmap_req req;
921 memset(&req, 0, sizeof(req));
922 if (nlk->rx_ring.pg_vec)
923 netlink_set_ring(sk, &req, true, false);
924 memset(&req, 0, sizeof(req));
925 if (nlk->tx_ring.pg_vec)
926 netlink_set_ring(sk, &req, true, true);
928 #endif /* CONFIG_NETLINK_MMAP */
930 if (!sock_flag(sk, SOCK_DEAD)) {
931 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
935 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
936 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
937 WARN_ON(nlk_sk(sk)->groups);
940 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
941 * SMP. Look, when several writers sleep and reader wakes them up, all but one
942 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
943 * this, _but_ remember, it adds useless work on UP machines.
946 void netlink_table_grab(void)
947 __acquires(nl_table_lock)
951 write_lock_irq(&nl_table_lock);
953 if (atomic_read(&nl_table_users)) {
954 DECLARE_WAITQUEUE(wait, current);
956 add_wait_queue_exclusive(&nl_table_wait, &wait);
958 set_current_state(TASK_UNINTERRUPTIBLE);
959 if (atomic_read(&nl_table_users) == 0)
961 write_unlock_irq(&nl_table_lock);
963 write_lock_irq(&nl_table_lock);
966 __set_current_state(TASK_RUNNING);
967 remove_wait_queue(&nl_table_wait, &wait);
971 void netlink_table_ungrab(void)
972 __releases(nl_table_lock)
974 write_unlock_irq(&nl_table_lock);
975 wake_up(&nl_table_wait);
979 netlink_lock_table(void)
981 /* read_lock() synchronizes us to netlink_table_grab */
983 read_lock(&nl_table_lock);
984 atomic_inc(&nl_table_users);
985 read_unlock(&nl_table_lock);
989 netlink_unlock_table(void)
991 if (atomic_dec_and_test(&nl_table_users))
992 wake_up(&nl_table_wait);
995 struct netlink_compare_arg
1001 static bool netlink_compare(void *ptr, void *arg)
1003 struct netlink_compare_arg *x = arg;
1004 struct sock *sk = ptr;
1006 return nlk_sk(sk)->portid == x->portid &&
1007 net_eq(sock_net(sk), x->net);
1010 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
1013 struct netlink_compare_arg arg = {
1019 hash = rhashtable_hashfn(&table->hash, &portid, sizeof(portid));
1021 return rhashtable_lookup_compare(&table->hash, hash,
1022 &netlink_compare, &arg);
1025 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
1027 struct netlink_table *table = &nl_table[protocol];
1031 sk = __netlink_lookup(table, portid, net);
1039 static const struct proto_ops netlink_ops;
1042 netlink_update_listeners(struct sock *sk)
1044 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1047 struct listeners *listeners;
1049 listeners = nl_deref_protected(tbl->listeners);
1053 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
1055 sk_for_each_bound(sk, &tbl->mc_list) {
1056 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
1057 mask |= nlk_sk(sk)->groups[i];
1059 listeners->masks[i] = mask;
1061 /* this function is only called with the netlink table "grabbed", which
1062 * makes sure updates are visible before bind or setsockopt return. */
1065 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
1067 struct netlink_table *table = &nl_table[sk->sk_protocol];
1068 int err = -EADDRINUSE;
1070 mutex_lock(&nl_sk_hash_lock);
1071 if (__netlink_lookup(table, portid, net))
1075 if (nlk_sk(sk)->portid)
1079 if (BITS_PER_LONG > 32 && unlikely(table->hash.nelems >= UINT_MAX))
1082 nlk_sk(sk)->portid = portid;
1084 rhashtable_insert(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL);
1087 mutex_unlock(&nl_sk_hash_lock);
1091 static void netlink_remove(struct sock *sk)
1093 struct netlink_table *table;
1095 mutex_lock(&nl_sk_hash_lock);
1096 table = &nl_table[sk->sk_protocol];
1097 if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL)) {
1098 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
1101 mutex_unlock(&nl_sk_hash_lock);
1103 netlink_table_grab();
1104 if (nlk_sk(sk)->subscriptions)
1105 __sk_del_bind_node(sk);
1106 netlink_table_ungrab();
1109 static struct proto netlink_proto = {
1111 .owner = THIS_MODULE,
1112 .obj_size = sizeof(struct netlink_sock),
1115 static int __netlink_create(struct net *net, struct socket *sock,
1116 struct mutex *cb_mutex, int protocol)
1119 struct netlink_sock *nlk;
1121 sock->ops = &netlink_ops;
1123 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
1127 sock_init_data(sock, sk);
1131 nlk->cb_mutex = cb_mutex;
1133 nlk->cb_mutex = &nlk->cb_def_mutex;
1134 mutex_init(nlk->cb_mutex);
1136 init_waitqueue_head(&nlk->wait);
1137 #ifdef CONFIG_NETLINK_MMAP
1138 mutex_init(&nlk->pg_vec_lock);
1141 sk->sk_destruct = netlink_sock_destruct;
1142 sk->sk_protocol = protocol;
1146 static int netlink_create(struct net *net, struct socket *sock, int protocol,
1149 struct module *module = NULL;
1150 struct mutex *cb_mutex;
1151 struct netlink_sock *nlk;
1152 int (*bind)(int group);
1153 void (*unbind)(int group);
1156 sock->state = SS_UNCONNECTED;
1158 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1159 return -ESOCKTNOSUPPORT;
1161 if (protocol < 0 || protocol >= MAX_LINKS)
1162 return -EPROTONOSUPPORT;
1164 netlink_lock_table();
1165 #ifdef CONFIG_MODULES
1166 if (!nl_table[protocol].registered) {
1167 netlink_unlock_table();
1168 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
1169 netlink_lock_table();
1172 if (nl_table[protocol].registered &&
1173 try_module_get(nl_table[protocol].module))
1174 module = nl_table[protocol].module;
1176 err = -EPROTONOSUPPORT;
1177 cb_mutex = nl_table[protocol].cb_mutex;
1178 bind = nl_table[protocol].bind;
1179 unbind = nl_table[protocol].unbind;
1180 netlink_unlock_table();
1185 err = __netlink_create(net, sock, cb_mutex, protocol);
1190 sock_prot_inuse_add(net, &netlink_proto, 1);
1193 nlk = nlk_sk(sock->sk);
1194 nlk->module = module;
1195 nlk->netlink_bind = bind;
1196 nlk->netlink_unbind = unbind;
1205 static int netlink_release(struct socket *sock)
1207 struct sock *sk = sock->sk;
1208 struct netlink_sock *nlk;
1218 * OK. Socket is unlinked, any packets that arrive now
1223 wake_up_interruptible_all(&nlk->wait);
1225 skb_queue_purge(&sk->sk_write_queue);
1228 struct netlink_notify n = {
1229 .net = sock_net(sk),
1230 .protocol = sk->sk_protocol,
1231 .portid = nlk->portid,
1233 atomic_notifier_call_chain(&netlink_chain,
1234 NETLINK_URELEASE, &n);
1237 module_put(nlk->module);
1239 netlink_table_grab();
1240 if (netlink_is_kernel(sk)) {
1241 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
1242 if (--nl_table[sk->sk_protocol].registered == 0) {
1243 struct listeners *old;
1245 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
1246 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
1247 kfree_rcu(old, rcu);
1248 nl_table[sk->sk_protocol].module = NULL;
1249 nl_table[sk->sk_protocol].bind = NULL;
1250 nl_table[sk->sk_protocol].unbind = NULL;
1251 nl_table[sk->sk_protocol].flags = 0;
1252 nl_table[sk->sk_protocol].registered = 0;
1254 } else if (nlk->subscriptions) {
1255 netlink_update_listeners(sk);
1257 netlink_table_ungrab();
1259 /* Wait for readers to complete */
1266 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
1272 static int netlink_autobind(struct socket *sock)
1274 struct sock *sk = sock->sk;
1275 struct net *net = sock_net(sk);
1276 struct netlink_table *table = &nl_table[sk->sk_protocol];
1277 s32 portid = task_tgid_vnr(current);
1279 static s32 rover = -4097;
1284 if (__netlink_lookup(table, portid, net)) {
1285 /* Bind collision, search negative portid values. */
1294 err = netlink_insert(sk, net, portid);
1295 if (err == -EADDRINUSE)
1298 /* If 2 threads race to autobind, that is fine. */
1306 * __netlink_ns_capable - General netlink message capability test
1307 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
1308 * @user_ns: The user namespace of the capability to use
1309 * @cap: The capability to use
1311 * Test to see if the opener of the socket we received the message
1312 * from had when the netlink socket was created and the sender of the
1313 * message has has the capability @cap in the user namespace @user_ns.
1315 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
1316 struct user_namespace *user_ns, int cap)
1318 return ((nsp->flags & NETLINK_SKB_DST) ||
1319 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
1320 ns_capable(user_ns, cap);
1322 EXPORT_SYMBOL(__netlink_ns_capable);
1325 * netlink_ns_capable - General netlink message capability test
1326 * @skb: socket buffer holding a netlink command from userspace
1327 * @user_ns: The user namespace of the capability to use
1328 * @cap: The capability to use
1330 * Test to see if the opener of the socket we received the message
1331 * from had when the netlink socket was created and the sender of the
1332 * message has has the capability @cap in the user namespace @user_ns.
1334 bool netlink_ns_capable(const struct sk_buff *skb,
1335 struct user_namespace *user_ns, int cap)
1337 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
1339 EXPORT_SYMBOL(netlink_ns_capable);
1342 * netlink_capable - Netlink global message capability test
1343 * @skb: socket buffer holding a netlink command from userspace
1344 * @cap: The capability to use
1346 * Test to see if the opener of the socket we received the message
1347 * from had when the netlink socket was created and the sender of the
1348 * message has has the capability @cap in all user namespaces.
1350 bool netlink_capable(const struct sk_buff *skb, int cap)
1352 return netlink_ns_capable(skb, &init_user_ns, cap);
1354 EXPORT_SYMBOL(netlink_capable);
1357 * netlink_net_capable - Netlink network namespace message capability test
1358 * @skb: socket buffer holding a netlink command from userspace
1359 * @cap: The capability to use
1361 * Test to see if the opener of the socket we received the message
1362 * from had when the netlink socket was created and the sender of the
1363 * message has has the capability @cap over the network namespace of
1364 * the socket we received the message from.
1366 bool netlink_net_capable(const struct sk_buff *skb, int cap)
1368 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
1370 EXPORT_SYMBOL(netlink_net_capable);
1372 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
1374 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
1375 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
1379 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
1381 struct netlink_sock *nlk = nlk_sk(sk);
1383 if (nlk->subscriptions && !subscriptions)
1384 __sk_del_bind_node(sk);
1385 else if (!nlk->subscriptions && subscriptions)
1386 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
1387 nlk->subscriptions = subscriptions;
1390 static int netlink_realloc_groups(struct sock *sk)
1392 struct netlink_sock *nlk = nlk_sk(sk);
1393 unsigned int groups;
1394 unsigned long *new_groups;
1397 netlink_table_grab();
1399 groups = nl_table[sk->sk_protocol].groups;
1400 if (!nl_table[sk->sk_protocol].registered) {
1405 if (nlk->ngroups >= groups)
1408 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
1409 if (new_groups == NULL) {
1413 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
1414 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
1416 nlk->groups = new_groups;
1417 nlk->ngroups = groups;
1419 netlink_table_ungrab();
1423 static void netlink_unbind(int group, long unsigned int groups,
1424 struct netlink_sock *nlk)
1428 if (!nlk->netlink_unbind)
1431 for (undo = 0; undo < group; undo++)
1432 if (test_bit(group, &groups))
1433 nlk->netlink_unbind(undo);
1436 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1439 struct sock *sk = sock->sk;
1440 struct net *net = sock_net(sk);
1441 struct netlink_sock *nlk = nlk_sk(sk);
1442 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1444 long unsigned int groups = nladdr->nl_groups;
1446 if (addr_len < sizeof(struct sockaddr_nl))
1449 if (nladdr->nl_family != AF_NETLINK)
1452 /* Only superuser is allowed to listen multicasts */
1454 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1456 err = netlink_realloc_groups(sk);
1462 if (nladdr->nl_pid != nlk->portid)
1465 if (nlk->netlink_bind && groups) {
1468 for (group = 0; group < nlk->ngroups; group++) {
1469 if (!test_bit(group, &groups))
1471 err = nlk->netlink_bind(group);
1474 netlink_unbind(group, groups, nlk);
1480 err = nladdr->nl_pid ?
1481 netlink_insert(sk, net, nladdr->nl_pid) :
1482 netlink_autobind(sock);
1484 netlink_unbind(nlk->ngroups - 1, groups, nlk);
1489 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1492 netlink_table_grab();
1493 netlink_update_subscriptions(sk, nlk->subscriptions +
1495 hweight32(nlk->groups[0]));
1496 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1497 netlink_update_listeners(sk);
1498 netlink_table_ungrab();
1503 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1504 int alen, int flags)
1507 struct sock *sk = sock->sk;
1508 struct netlink_sock *nlk = nlk_sk(sk);
1509 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1511 if (alen < sizeof(addr->sa_family))
1514 if (addr->sa_family == AF_UNSPEC) {
1515 sk->sk_state = NETLINK_UNCONNECTED;
1516 nlk->dst_portid = 0;
1520 if (addr->sa_family != AF_NETLINK)
1523 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1524 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1528 err = netlink_autobind(sock);
1531 sk->sk_state = NETLINK_CONNECTED;
1532 nlk->dst_portid = nladdr->nl_pid;
1533 nlk->dst_group = ffs(nladdr->nl_groups);
1539 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1540 int *addr_len, int peer)
1542 struct sock *sk = sock->sk;
1543 struct netlink_sock *nlk = nlk_sk(sk);
1544 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1546 nladdr->nl_family = AF_NETLINK;
1548 *addr_len = sizeof(*nladdr);
1551 nladdr->nl_pid = nlk->dst_portid;
1552 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1554 nladdr->nl_pid = nlk->portid;
1555 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1560 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1563 struct netlink_sock *nlk;
1565 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1567 return ERR_PTR(-ECONNREFUSED);
1569 /* Don't bother queuing skb if kernel socket has no input function */
1571 if (sock->sk_state == NETLINK_CONNECTED &&
1572 nlk->dst_portid != nlk_sk(ssk)->portid) {
1574 return ERR_PTR(-ECONNREFUSED);
1579 struct sock *netlink_getsockbyfilp(struct file *filp)
1581 struct inode *inode = file_inode(filp);
1584 if (!S_ISSOCK(inode->i_mode))
1585 return ERR_PTR(-ENOTSOCK);
1587 sock = SOCKET_I(inode)->sk;
1588 if (sock->sk_family != AF_NETLINK)
1589 return ERR_PTR(-EINVAL);
1595 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1598 struct sk_buff *skb;
1601 if (size <= NLMSG_GOODSIZE || broadcast)
1602 return alloc_skb(size, GFP_KERNEL);
1604 size = SKB_DATA_ALIGN(size) +
1605 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1607 data = vmalloc(size);
1611 skb = build_skb(data, size);
1616 skb->destructor = netlink_skb_destructor;
1623 * Attach a skb to a netlink socket.
1624 * The caller must hold a reference to the destination socket. On error, the
1625 * reference is dropped. The skb is not send to the destination, just all
1626 * all error checks are performed and memory in the queue is reserved.
1628 * < 0: error. skb freed, reference to sock dropped.
1630 * 1: repeat lookup - reference dropped while waiting for socket memory.
1632 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1633 long *timeo, struct sock *ssk)
1635 struct netlink_sock *nlk;
1639 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1640 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1641 !netlink_skb_is_mmaped(skb)) {
1642 DECLARE_WAITQUEUE(wait, current);
1644 if (!ssk || netlink_is_kernel(ssk))
1645 netlink_overrun(sk);
1651 __set_current_state(TASK_INTERRUPTIBLE);
1652 add_wait_queue(&nlk->wait, &wait);
1654 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1655 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1656 !sock_flag(sk, SOCK_DEAD))
1657 *timeo = schedule_timeout(*timeo);
1659 __set_current_state(TASK_RUNNING);
1660 remove_wait_queue(&nlk->wait, &wait);
1663 if (signal_pending(current)) {
1665 return sock_intr_errno(*timeo);
1669 netlink_skb_set_owner_r(skb, sk);
1673 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1677 netlink_deliver_tap(skb);
1679 #ifdef CONFIG_NETLINK_MMAP
1680 if (netlink_skb_is_mmaped(skb))
1681 netlink_queue_mmaped_skb(sk, skb);
1682 else if (netlink_rx_is_mmaped(sk))
1683 netlink_ring_set_copied(sk, skb);
1685 #endif /* CONFIG_NETLINK_MMAP */
1686 skb_queue_tail(&sk->sk_receive_queue, skb);
1687 sk->sk_data_ready(sk);
1691 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1693 int len = __netlink_sendskb(sk, skb);
1699 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1705 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1709 WARN_ON(skb->sk != NULL);
1710 if (netlink_skb_is_mmaped(skb))
1713 delta = skb->end - skb->tail;
1714 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1717 if (skb_shared(skb)) {
1718 struct sk_buff *nskb = skb_clone(skb, allocation);
1725 if (!pskb_expand_head(skb, 0, -delta, allocation))
1726 skb->truesize -= delta;
1731 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1735 struct netlink_sock *nlk = nlk_sk(sk);
1737 ret = -ECONNREFUSED;
1738 if (nlk->netlink_rcv != NULL) {
1740 netlink_skb_set_owner_r(skb, sk);
1741 NETLINK_CB(skb).sk = ssk;
1742 netlink_deliver_tap_kernel(sk, ssk, skb);
1743 nlk->netlink_rcv(skb);
1752 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1753 u32 portid, int nonblock)
1759 skb = netlink_trim(skb, gfp_any());
1761 timeo = sock_sndtimeo(ssk, nonblock);
1763 sk = netlink_getsockbyportid(ssk, portid);
1768 if (netlink_is_kernel(sk))
1769 return netlink_unicast_kernel(sk, skb, ssk);
1771 if (sk_filter(sk, skb)) {
1778 err = netlink_attachskb(sk, skb, &timeo, ssk);
1784 return netlink_sendskb(sk, skb);
1786 EXPORT_SYMBOL(netlink_unicast);
1788 struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
1789 u32 dst_portid, gfp_t gfp_mask)
1791 #ifdef CONFIG_NETLINK_MMAP
1792 struct sock *sk = NULL;
1793 struct sk_buff *skb;
1794 struct netlink_ring *ring;
1795 struct nl_mmap_hdr *hdr;
1796 unsigned int maxlen;
1798 sk = netlink_getsockbyportid(ssk, dst_portid);
1802 ring = &nlk_sk(sk)->rx_ring;
1803 /* fast-path without atomic ops for common case: non-mmaped receiver */
1804 if (ring->pg_vec == NULL)
1807 if (ring->frame_size - NL_MMAP_HDRLEN < size)
1810 skb = alloc_skb_head(gfp_mask);
1814 spin_lock_bh(&sk->sk_receive_queue.lock);
1815 /* check again under lock */
1816 if (ring->pg_vec == NULL)
1819 /* check again under lock */
1820 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
1824 netlink_forward_ring(ring);
1825 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
1828 netlink_ring_setup_skb(skb, sk, ring, hdr);
1829 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
1830 atomic_inc(&ring->pending);
1831 netlink_increment_head(ring);
1833 spin_unlock_bh(&sk->sk_receive_queue.lock);
1838 spin_unlock_bh(&sk->sk_receive_queue.lock);
1839 netlink_overrun(sk);
1846 spin_unlock_bh(&sk->sk_receive_queue.lock);
1851 return alloc_skb(size, gfp_mask);
1853 EXPORT_SYMBOL_GPL(netlink_alloc_skb);
1855 int netlink_has_listeners(struct sock *sk, unsigned int group)
1858 struct listeners *listeners;
1860 BUG_ON(!netlink_is_kernel(sk));
1863 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1865 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1866 res = test_bit(group - 1, listeners->masks);
1872 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1874 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1876 struct netlink_sock *nlk = nlk_sk(sk);
1878 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1879 !test_bit(NETLINK_CONGESTED, &nlk->state)) {
1880 netlink_skb_set_owner_r(skb, sk);
1881 __netlink_sendskb(sk, skb);
1882 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1887 struct netlink_broadcast_data {
1888 struct sock *exclude_sk;
1893 int delivery_failure;
1897 struct sk_buff *skb, *skb2;
1898 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1902 static void do_one_broadcast(struct sock *sk,
1903 struct netlink_broadcast_data *p)
1905 struct netlink_sock *nlk = nlk_sk(sk);
1908 if (p->exclude_sk == sk)
1911 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1912 !test_bit(p->group - 1, nlk->groups))
1915 if (!net_eq(sock_net(sk), p->net))
1919 netlink_overrun(sk);
1924 if (p->skb2 == NULL) {
1925 if (skb_shared(p->skb)) {
1926 p->skb2 = skb_clone(p->skb, p->allocation);
1928 p->skb2 = skb_get(p->skb);
1930 * skb ownership may have been set when
1931 * delivered to a previous socket.
1933 skb_orphan(p->skb2);
1936 if (p->skb2 == NULL) {
1937 netlink_overrun(sk);
1938 /* Clone failed. Notify ALL listeners. */
1940 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1941 p->delivery_failure = 1;
1942 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1945 } else if (sk_filter(sk, p->skb2)) {
1948 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1949 netlink_overrun(sk);
1950 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1951 p->delivery_failure = 1;
1953 p->congested |= val;
1960 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1961 u32 group, gfp_t allocation,
1962 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1965 struct net *net = sock_net(ssk);
1966 struct netlink_broadcast_data info;
1969 skb = netlink_trim(skb, allocation);
1971 info.exclude_sk = ssk;
1973 info.portid = portid;
1976 info.delivery_failure = 0;
1979 info.allocation = allocation;
1982 info.tx_filter = filter;
1983 info.tx_data = filter_data;
1985 /* While we sleep in clone, do not allow to change socket list */
1987 netlink_lock_table();
1989 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1990 do_one_broadcast(sk, &info);
1994 netlink_unlock_table();
1996 if (info.delivery_failure) {
1997 kfree_skb(info.skb2);
2000 consume_skb(info.skb2);
2002 if (info.delivered) {
2003 if (info.congested && (allocation & __GFP_WAIT))
2009 EXPORT_SYMBOL(netlink_broadcast_filtered);
2011 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
2012 u32 group, gfp_t allocation)
2014 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
2017 EXPORT_SYMBOL(netlink_broadcast);
2019 struct netlink_set_err_data {
2020 struct sock *exclude_sk;
2026 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
2028 struct netlink_sock *nlk = nlk_sk(sk);
2031 if (sk == p->exclude_sk)
2034 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
2037 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
2038 !test_bit(p->group - 1, nlk->groups))
2041 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
2046 sk->sk_err = p->code;
2047 sk->sk_error_report(sk);
2053 * netlink_set_err - report error to broadcast listeners
2054 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2055 * @portid: the PORTID of a process that we want to skip (if any)
2056 * @group: the broadcast group that will notice the error
2057 * @code: error code, must be negative (as usual in kernelspace)
2059 * This function returns the number of broadcast listeners that have set the
2060 * NETLINK_RECV_NO_ENOBUFS socket option.
2062 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
2064 struct netlink_set_err_data info;
2068 info.exclude_sk = ssk;
2069 info.portid = portid;
2071 /* sk->sk_err wants a positive error value */
2074 read_lock(&nl_table_lock);
2076 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2077 ret += do_one_set_err(sk, &info);
2079 read_unlock(&nl_table_lock);
2082 EXPORT_SYMBOL(netlink_set_err);
2084 /* must be called with netlink table grabbed */
2085 static void netlink_update_socket_mc(struct netlink_sock *nlk,
2089 int old, new = !!is_new, subscriptions;
2091 old = test_bit(group - 1, nlk->groups);
2092 subscriptions = nlk->subscriptions - old + new;
2094 __set_bit(group - 1, nlk->groups);
2096 __clear_bit(group - 1, nlk->groups);
2097 netlink_update_subscriptions(&nlk->sk, subscriptions);
2098 netlink_update_listeners(&nlk->sk);
2101 static int netlink_setsockopt(struct socket *sock, int level, int optname,
2102 char __user *optval, unsigned int optlen)
2104 struct sock *sk = sock->sk;
2105 struct netlink_sock *nlk = nlk_sk(sk);
2106 unsigned int val = 0;
2109 if (level != SOL_NETLINK)
2110 return -ENOPROTOOPT;
2112 if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
2113 optlen >= sizeof(int) &&
2114 get_user(val, (unsigned int __user *)optval))
2118 case NETLINK_PKTINFO:
2120 nlk->flags |= NETLINK_RECV_PKTINFO;
2122 nlk->flags &= ~NETLINK_RECV_PKTINFO;
2125 case NETLINK_ADD_MEMBERSHIP:
2126 case NETLINK_DROP_MEMBERSHIP: {
2127 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
2129 err = netlink_realloc_groups(sk);
2132 if (!val || val - 1 >= nlk->ngroups)
2134 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
2135 err = nlk->netlink_bind(val);
2139 netlink_table_grab();
2140 netlink_update_socket_mc(nlk, val,
2141 optname == NETLINK_ADD_MEMBERSHIP);
2142 netlink_table_ungrab();
2143 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
2144 nlk->netlink_unbind(val);
2149 case NETLINK_BROADCAST_ERROR:
2151 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
2153 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
2156 case NETLINK_NO_ENOBUFS:
2158 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
2159 clear_bit(NETLINK_CONGESTED, &nlk->state);
2160 wake_up_interruptible(&nlk->wait);
2162 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
2166 #ifdef CONFIG_NETLINK_MMAP
2167 case NETLINK_RX_RING:
2168 case NETLINK_TX_RING: {
2169 struct nl_mmap_req req;
2171 /* Rings might consume more memory than queue limits, require
2174 if (!capable(CAP_NET_ADMIN))
2176 if (optlen < sizeof(req))
2178 if (copy_from_user(&req, optval, sizeof(req)))
2180 err = netlink_set_ring(sk, &req, false,
2181 optname == NETLINK_TX_RING);
2184 #endif /* CONFIG_NETLINK_MMAP */
2191 static int netlink_getsockopt(struct socket *sock, int level, int optname,
2192 char __user *optval, int __user *optlen)
2194 struct sock *sk = sock->sk;
2195 struct netlink_sock *nlk = nlk_sk(sk);
2198 if (level != SOL_NETLINK)
2199 return -ENOPROTOOPT;
2201 if (get_user(len, optlen))
2207 case NETLINK_PKTINFO:
2208 if (len < sizeof(int))
2211 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
2212 if (put_user(len, optlen) ||
2213 put_user(val, optval))
2217 case NETLINK_BROADCAST_ERROR:
2218 if (len < sizeof(int))
2221 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
2222 if (put_user(len, optlen) ||
2223 put_user(val, optval))
2227 case NETLINK_NO_ENOBUFS:
2228 if (len < sizeof(int))
2231 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
2232 if (put_user(len, optlen) ||
2233 put_user(val, optval))
2243 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
2245 struct nl_pktinfo info;
2247 info.group = NETLINK_CB(skb).dst_group;
2248 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
2251 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
2252 struct msghdr *msg, size_t len)
2254 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2255 struct sock *sk = sock->sk;
2256 struct netlink_sock *nlk = nlk_sk(sk);
2257 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2260 struct sk_buff *skb;
2262 struct scm_cookie scm;
2263 u32 netlink_skb_flags = 0;
2265 if (msg->msg_flags&MSG_OOB)
2268 if (NULL == siocb->scm)
2271 err = scm_send(sock, msg, siocb->scm, true);
2275 if (msg->msg_namelen) {
2277 if (addr->nl_family != AF_NETLINK)
2279 dst_portid = addr->nl_pid;
2280 dst_group = ffs(addr->nl_groups);
2282 if ((dst_group || dst_portid) &&
2283 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
2285 netlink_skb_flags |= NETLINK_SKB_DST;
2287 dst_portid = nlk->dst_portid;
2288 dst_group = nlk->dst_group;
2292 err = netlink_autobind(sock);
2297 if (netlink_tx_is_mmaped(sk) &&
2298 msg->msg_iov->iov_base == NULL) {
2299 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
2305 if (len > sk->sk_sndbuf - 32)
2308 skb = netlink_alloc_large_skb(len, dst_group);
2312 NETLINK_CB(skb).portid = nlk->portid;
2313 NETLINK_CB(skb).dst_group = dst_group;
2314 NETLINK_CB(skb).creds = siocb->scm->creds;
2315 NETLINK_CB(skb).flags = netlink_skb_flags;
2318 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
2323 err = security_netlink_send(sk, skb);
2330 atomic_inc(&skb->users);
2331 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
2333 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
2336 scm_destroy(siocb->scm);
2340 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
2341 struct msghdr *msg, size_t len,
2344 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2345 struct scm_cookie scm;
2346 struct sock *sk = sock->sk;
2347 struct netlink_sock *nlk = nlk_sk(sk);
2348 int noblock = flags&MSG_DONTWAIT;
2350 struct sk_buff *skb, *data_skb;
2358 skb = skb_recv_datagram(sk, flags, noblock, &err);
2364 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2365 if (unlikely(skb_shinfo(skb)->frag_list)) {
2367 * If this skb has a frag_list, then here that means that we
2368 * will have to use the frag_list skb's data for compat tasks
2369 * and the regular skb's data for normal (non-compat) tasks.
2371 * If we need to send the compat skb, assign it to the
2372 * 'data_skb' variable so that it will be used below for data
2373 * copying. We keep 'skb' for everything else, including
2374 * freeing both later.
2376 if (flags & MSG_CMSG_COMPAT)
2377 data_skb = skb_shinfo(skb)->frag_list;
2381 /* Record the max length of recvmsg() calls for future allocations */
2382 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
2383 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
2386 copied = data_skb->len;
2388 msg->msg_flags |= MSG_TRUNC;
2392 skb_reset_transport_header(data_skb);
2393 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
2395 if (msg->msg_name) {
2396 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2397 addr->nl_family = AF_NETLINK;
2399 addr->nl_pid = NETLINK_CB(skb).portid;
2400 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2401 msg->msg_namelen = sizeof(*addr);
2404 if (nlk->flags & NETLINK_RECV_PKTINFO)
2405 netlink_cmsg_recv_pktinfo(msg, skb);
2407 if (NULL == siocb->scm) {
2408 memset(&scm, 0, sizeof(scm));
2411 siocb->scm->creds = *NETLINK_CREDS(skb);
2412 if (flags & MSG_TRUNC)
2413 copied = data_skb->len;
2415 skb_free_datagram(sk, skb);
2417 if (nlk->cb_running &&
2418 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2419 ret = netlink_dump(sk);
2422 sk->sk_error_report(sk);
2426 scm_recv(sock, msg, siocb->scm, flags);
2428 netlink_rcv_wake(sk);
2429 return err ? : copied;
2432 static void netlink_data_ready(struct sock *sk)
2438 * We export these functions to other modules. They provide a
2439 * complete set of kernel non-blocking support for message
2444 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2445 struct netlink_kernel_cfg *cfg)
2447 struct socket *sock;
2449 struct netlink_sock *nlk;
2450 struct listeners *listeners = NULL;
2451 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2452 unsigned int groups;
2456 if (unit < 0 || unit >= MAX_LINKS)
2459 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2463 * We have to just have a reference on the net from sk, but don't
2464 * get_net it. Besides, we cannot get and then put the net here.
2465 * So we create one inside init_net and the move it to net.
2468 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
2469 goto out_sock_release_nosk;
2472 sk_change_net(sk, net);
2474 if (!cfg || cfg->groups < 32)
2477 groups = cfg->groups;
2479 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2481 goto out_sock_release;
2483 sk->sk_data_ready = netlink_data_ready;
2484 if (cfg && cfg->input)
2485 nlk_sk(sk)->netlink_rcv = cfg->input;
2487 if (netlink_insert(sk, net, 0))
2488 goto out_sock_release;
2491 nlk->flags |= NETLINK_KERNEL_SOCKET;
2493 netlink_table_grab();
2494 if (!nl_table[unit].registered) {
2495 nl_table[unit].groups = groups;
2496 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2497 nl_table[unit].cb_mutex = cb_mutex;
2498 nl_table[unit].module = module;
2500 nl_table[unit].bind = cfg->bind;
2501 nl_table[unit].flags = cfg->flags;
2503 nl_table[unit].compare = cfg->compare;
2505 nl_table[unit].registered = 1;
2508 nl_table[unit].registered++;
2510 netlink_table_ungrab();
2515 netlink_kernel_release(sk);
2518 out_sock_release_nosk:
2522 EXPORT_SYMBOL(__netlink_kernel_create);
2525 netlink_kernel_release(struct sock *sk)
2527 sk_release_kernel(sk);
2529 EXPORT_SYMBOL(netlink_kernel_release);
2531 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2533 struct listeners *new, *old;
2534 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2539 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2540 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2543 old = nl_deref_protected(tbl->listeners);
2544 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2545 rcu_assign_pointer(tbl->listeners, new);
2547 kfree_rcu(old, rcu);
2549 tbl->groups = groups;
2555 * netlink_change_ngroups - change number of multicast groups
2557 * This changes the number of multicast groups that are available
2558 * on a certain netlink family. Note that it is not possible to
2559 * change the number of groups to below 32. Also note that it does
2560 * not implicitly call netlink_clear_multicast_users() when the
2561 * number of groups is reduced.
2563 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2564 * @groups: The new number of groups.
2566 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2570 netlink_table_grab();
2571 err = __netlink_change_ngroups(sk, groups);
2572 netlink_table_ungrab();
2577 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2580 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2582 sk_for_each_bound(sk, &tbl->mc_list)
2583 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2587 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2589 struct nlmsghdr *nlh;
2590 int size = nlmsg_msg_size(len);
2592 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2593 nlh->nlmsg_type = type;
2594 nlh->nlmsg_len = size;
2595 nlh->nlmsg_flags = flags;
2596 nlh->nlmsg_pid = portid;
2597 nlh->nlmsg_seq = seq;
2598 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2599 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2602 EXPORT_SYMBOL(__nlmsg_put);
2605 * It looks a bit ugly.
2606 * It would be better to create kernel thread.
2609 static int netlink_dump(struct sock *sk)
2611 struct netlink_sock *nlk = nlk_sk(sk);
2612 struct netlink_callback *cb;
2613 struct sk_buff *skb = NULL;
2614 struct nlmsghdr *nlh;
2615 int len, err = -ENOBUFS;
2618 mutex_lock(nlk->cb_mutex);
2619 if (!nlk->cb_running) {
2625 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2627 if (!netlink_rx_is_mmaped(sk) &&
2628 atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2631 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2632 * required, but it makes sense to _attempt_ a 16K bytes allocation
2633 * to reduce number of system calls on dump operations, if user
2634 * ever provided a big enough buffer.
2636 if (alloc_size < nlk->max_recvmsg_len) {
2637 skb = netlink_alloc_skb(sk,
2638 nlk->max_recvmsg_len,
2643 /* available room should be exact amount to avoid MSG_TRUNC */
2645 skb_reserve(skb, skb_tailroom(skb) -
2646 nlk->max_recvmsg_len);
2649 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2653 netlink_skb_set_owner_r(skb, sk);
2655 len = cb->dump(skb, cb);
2658 mutex_unlock(nlk->cb_mutex);
2660 if (sk_filter(sk, skb))
2663 __netlink_sendskb(sk, skb);
2667 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2671 nl_dump_check_consistent(cb, nlh);
2673 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2675 if (sk_filter(sk, skb))
2678 __netlink_sendskb(sk, skb);
2683 nlk->cb_running = false;
2684 mutex_unlock(nlk->cb_mutex);
2685 module_put(cb->module);
2686 consume_skb(cb->skb);
2690 mutex_unlock(nlk->cb_mutex);
2695 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2696 const struct nlmsghdr *nlh,
2697 struct netlink_dump_control *control)
2699 struct netlink_callback *cb;
2701 struct netlink_sock *nlk;
2704 /* Memory mapped dump requests need to be copied to avoid looping
2705 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2706 * a reference to the skb.
2708 if (netlink_skb_is_mmaped(skb)) {
2709 skb = skb_copy(skb, GFP_KERNEL);
2713 atomic_inc(&skb->users);
2715 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2717 ret = -ECONNREFUSED;
2722 mutex_lock(nlk->cb_mutex);
2723 /* A dump is in progress... */
2724 if (nlk->cb_running) {
2728 /* add reference of module which cb->dump belongs to */
2729 if (!try_module_get(control->module)) {
2730 ret = -EPROTONOSUPPORT;
2735 memset(cb, 0, sizeof(*cb));
2736 cb->dump = control->dump;
2737 cb->done = control->done;
2739 cb->data = control->data;
2740 cb->module = control->module;
2741 cb->min_dump_alloc = control->min_dump_alloc;
2744 nlk->cb_running = true;
2746 mutex_unlock(nlk->cb_mutex);
2748 ret = netlink_dump(sk);
2754 /* We successfully started a dump, by returning -EINTR we
2755 * signal not to send ACK even if it was requested.
2761 mutex_unlock(nlk->cb_mutex);
2766 EXPORT_SYMBOL(__netlink_dump_start);
2768 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2770 struct sk_buff *skb;
2771 struct nlmsghdr *rep;
2772 struct nlmsgerr *errmsg;
2773 size_t payload = sizeof(*errmsg);
2775 /* error messages get the original request appened */
2777 payload += nlmsg_len(nlh);
2779 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2780 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2784 sk = netlink_lookup(sock_net(in_skb->sk),
2785 in_skb->sk->sk_protocol,
2786 NETLINK_CB(in_skb).portid);
2788 sk->sk_err = ENOBUFS;
2789 sk->sk_error_report(sk);
2795 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2796 NLMSG_ERROR, payload, 0);
2797 errmsg = nlmsg_data(rep);
2798 errmsg->error = err;
2799 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
2800 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2802 EXPORT_SYMBOL(netlink_ack);
2804 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2807 struct nlmsghdr *nlh;
2810 while (skb->len >= nlmsg_total_size(0)) {
2813 nlh = nlmsg_hdr(skb);
2816 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2819 /* Only requests are handled by the kernel */
2820 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2823 /* Skip control messages */
2824 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2832 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2833 netlink_ack(skb, nlh, err);
2836 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2837 if (msglen > skb->len)
2839 skb_pull(skb, msglen);
2844 EXPORT_SYMBOL(netlink_rcv_skb);
2847 * nlmsg_notify - send a notification netlink message
2848 * @sk: netlink socket to use
2849 * @skb: notification message
2850 * @portid: destination netlink portid for reports or 0
2851 * @group: destination multicast group or 0
2852 * @report: 1 to report back, 0 to disable
2853 * @flags: allocation flags
2855 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2856 unsigned int group, int report, gfp_t flags)
2861 int exclude_portid = 0;
2864 atomic_inc(&skb->users);
2865 exclude_portid = portid;
2868 /* errors reported via destination sk->sk_err, but propagate
2869 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2870 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2876 err2 = nlmsg_unicast(sk, skb, portid);
2877 if (!err || err == -ESRCH)
2883 EXPORT_SYMBOL(nlmsg_notify);
2885 #ifdef CONFIG_PROC_FS
2886 struct nl_seq_iter {
2887 struct seq_net_private p;
2892 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
2894 struct nl_seq_iter *iter = seq->private;
2896 struct netlink_sock *nlk;
2900 for (i = 0; i < MAX_LINKS; i++) {
2901 struct rhashtable *ht = &nl_table[i].hash;
2902 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2904 for (j = 0; j < tbl->size; j++) {
2905 rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
2906 s = (struct sock *)nlk;
2908 if (sock_net(s) != seq_file_net(seq))
2922 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2925 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2928 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2930 struct netlink_sock *nlk;
2931 struct nl_seq_iter *iter;
2937 if (v == SEQ_START_TOKEN)
2938 return netlink_seq_socket_idx(seq, 0);
2940 net = seq_file_net(seq);
2941 iter = seq->private;
2944 rht_for_each_entry_rcu(nlk, nlk->node.next, node)
2945 if (net_eq(sock_net((struct sock *)nlk), net))
2949 j = iter->hash_idx + 1;
2952 struct rhashtable *ht = &nl_table[i].hash;
2953 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2955 for (; j < tbl->size; j++) {
2956 rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
2957 if (net_eq(sock_net((struct sock *)nlk), net)) {
2966 } while (++i < MAX_LINKS);
2971 static void netlink_seq_stop(struct seq_file *seq, void *v)
2977 static int netlink_seq_show(struct seq_file *seq, void *v)
2979 if (v == SEQ_START_TOKEN) {
2981 "sk Eth Pid Groups "
2982 "Rmem Wmem Dump Locks Drops Inode\n");
2985 struct netlink_sock *nlk = nlk_sk(s);
2987 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2991 nlk->groups ? (u32)nlk->groups[0] : 0,
2992 sk_rmem_alloc_get(s),
2993 sk_wmem_alloc_get(s),
2995 atomic_read(&s->sk_refcnt),
2996 atomic_read(&s->sk_drops),
3004 static const struct seq_operations netlink_seq_ops = {
3005 .start = netlink_seq_start,
3006 .next = netlink_seq_next,
3007 .stop = netlink_seq_stop,
3008 .show = netlink_seq_show,
3012 static int netlink_seq_open(struct inode *inode, struct file *file)
3014 return seq_open_net(inode, file, &netlink_seq_ops,
3015 sizeof(struct nl_seq_iter));
3018 static const struct file_operations netlink_seq_fops = {
3019 .owner = THIS_MODULE,
3020 .open = netlink_seq_open,
3022 .llseek = seq_lseek,
3023 .release = seq_release_net,
3028 int netlink_register_notifier(struct notifier_block *nb)
3030 return atomic_notifier_chain_register(&netlink_chain, nb);
3032 EXPORT_SYMBOL(netlink_register_notifier);
3034 int netlink_unregister_notifier(struct notifier_block *nb)
3036 return atomic_notifier_chain_unregister(&netlink_chain, nb);
3038 EXPORT_SYMBOL(netlink_unregister_notifier);
3040 static const struct proto_ops netlink_ops = {
3041 .family = PF_NETLINK,
3042 .owner = THIS_MODULE,
3043 .release = netlink_release,
3044 .bind = netlink_bind,
3045 .connect = netlink_connect,
3046 .socketpair = sock_no_socketpair,
3047 .accept = sock_no_accept,
3048 .getname = netlink_getname,
3049 .poll = netlink_poll,
3050 .ioctl = sock_no_ioctl,
3051 .listen = sock_no_listen,
3052 .shutdown = sock_no_shutdown,
3053 .setsockopt = netlink_setsockopt,
3054 .getsockopt = netlink_getsockopt,
3055 .sendmsg = netlink_sendmsg,
3056 .recvmsg = netlink_recvmsg,
3057 .mmap = netlink_mmap,
3058 .sendpage = sock_no_sendpage,
3061 static const struct net_proto_family netlink_family_ops = {
3062 .family = PF_NETLINK,
3063 .create = netlink_create,
3064 .owner = THIS_MODULE, /* for consistency 8) */
3067 static int __net_init netlink_net_init(struct net *net)
3069 #ifdef CONFIG_PROC_FS
3070 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
3076 static void __net_exit netlink_net_exit(struct net *net)
3078 #ifdef CONFIG_PROC_FS
3079 remove_proc_entry("netlink", net->proc_net);
3083 static void __init netlink_add_usersock_entry(void)
3085 struct listeners *listeners;
3088 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
3090 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3092 netlink_table_grab();
3094 nl_table[NETLINK_USERSOCK].groups = groups;
3095 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
3096 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
3097 nl_table[NETLINK_USERSOCK].registered = 1;
3098 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
3100 netlink_table_ungrab();
3103 static struct pernet_operations __net_initdata netlink_net_ops = {
3104 .init = netlink_net_init,
3105 .exit = netlink_net_exit,
3108 static int __init netlink_proto_init(void)
3111 int err = proto_register(&netlink_proto, 0);
3112 struct rhashtable_params ht_params = {
3113 .head_offset = offsetof(struct netlink_sock, node),
3114 .key_offset = offsetof(struct netlink_sock, portid),
3115 .key_len = sizeof(u32), /* portid */
3116 .hashfn = arch_fast_hash,
3117 .max_shift = 16, /* 64K */
3118 .grow_decision = rht_grow_above_75,
3119 .shrink_decision = rht_shrink_below_30,
3120 .mutex_is_held = lockdep_nl_sk_hash_is_held,
3126 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
3128 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
3132 for (i = 0; i < MAX_LINKS; i++) {
3133 if (rhashtable_init(&nl_table[i].hash, &ht_params) < 0) {
3135 rhashtable_destroy(&nl_table[i].hash);
3141 INIT_LIST_HEAD(&netlink_tap_all);
3143 netlink_add_usersock_entry();
3145 sock_register(&netlink_family_ops);
3146 register_pernet_subsys(&netlink_net_ops);
3147 /* The netlink device handler may be needed early. */
3152 panic("netlink_init: Cannot allocate nl_table\n");
3155 core_initcall(netlink_proto_init);