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 /* nl_table locking explained:
100 * Lookup and traversal are protected with nl_sk_hash_lock or nl_table_lock
101 * combined with an RCU read-side lock. Insertion and removal are protected
102 * with nl_sk_hash_lock while using RCU list modification primitives and may
103 * run in parallel to nl_table_lock protected lookups. Destruction of the
104 * Netlink socket may only occur *after* nl_table_lock has been acquired
105 * either during or after the socket has been removed from the list.
107 DEFINE_RWLOCK(nl_table_lock);
108 EXPORT_SYMBOL_GPL(nl_table_lock);
109 static atomic_t nl_table_users = ATOMIC_INIT(0);
111 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
113 /* Protects netlink socket hash table mutations */
114 DEFINE_MUTEX(nl_sk_hash_lock);
115 EXPORT_SYMBOL_GPL(nl_sk_hash_lock);
117 #ifdef CONFIG_PROVE_LOCKING
118 static int lockdep_nl_sk_hash_is_held(void *parent)
121 return lockdep_is_held(&nl_sk_hash_lock) || lockdep_is_held(&nl_table_lock);
126 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
128 static DEFINE_SPINLOCK(netlink_tap_lock);
129 static struct list_head netlink_tap_all __read_mostly;
131 static inline u32 netlink_group_mask(u32 group)
133 return group ? 1 << (group - 1) : 0;
136 int netlink_add_tap(struct netlink_tap *nt)
138 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
141 spin_lock(&netlink_tap_lock);
142 list_add_rcu(&nt->list, &netlink_tap_all);
143 spin_unlock(&netlink_tap_lock);
145 __module_get(nt->module);
149 EXPORT_SYMBOL_GPL(netlink_add_tap);
151 static int __netlink_remove_tap(struct netlink_tap *nt)
154 struct netlink_tap *tmp;
156 spin_lock(&netlink_tap_lock);
158 list_for_each_entry(tmp, &netlink_tap_all, list) {
160 list_del_rcu(&nt->list);
166 pr_warn("__netlink_remove_tap: %p not found\n", nt);
168 spin_unlock(&netlink_tap_lock);
170 if (found && nt->module)
171 module_put(nt->module);
173 return found ? 0 : -ENODEV;
176 int netlink_remove_tap(struct netlink_tap *nt)
180 ret = __netlink_remove_tap(nt);
185 EXPORT_SYMBOL_GPL(netlink_remove_tap);
187 static bool netlink_filter_tap(const struct sk_buff *skb)
189 struct sock *sk = skb->sk;
191 /* We take the more conservative approach and
192 * whitelist socket protocols that may pass.
194 switch (sk->sk_protocol) {
196 case NETLINK_USERSOCK:
197 case NETLINK_SOCK_DIAG:
200 case NETLINK_FIB_LOOKUP:
201 case NETLINK_NETFILTER:
202 case NETLINK_GENERIC:
209 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
210 struct net_device *dev)
212 struct sk_buff *nskb;
213 struct sock *sk = skb->sk;
217 nskb = skb_clone(skb, GFP_ATOMIC);
220 nskb->protocol = htons((u16) sk->sk_protocol);
221 nskb->pkt_type = netlink_is_kernel(sk) ?
222 PACKET_KERNEL : PACKET_USER;
223 skb_reset_network_header(nskb);
224 ret = dev_queue_xmit(nskb);
225 if (unlikely(ret > 0))
226 ret = net_xmit_errno(ret);
233 static void __netlink_deliver_tap(struct sk_buff *skb)
236 struct netlink_tap *tmp;
238 if (!netlink_filter_tap(skb))
241 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
242 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
248 static void netlink_deliver_tap(struct sk_buff *skb)
252 if (unlikely(!list_empty(&netlink_tap_all)))
253 __netlink_deliver_tap(skb);
258 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
261 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
262 netlink_deliver_tap(skb);
265 static void netlink_overrun(struct sock *sk)
267 struct netlink_sock *nlk = nlk_sk(sk);
269 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
270 if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
271 sk->sk_err = ENOBUFS;
272 sk->sk_error_report(sk);
275 atomic_inc(&sk->sk_drops);
278 static void netlink_rcv_wake(struct sock *sk)
280 struct netlink_sock *nlk = nlk_sk(sk);
282 if (skb_queue_empty(&sk->sk_receive_queue))
283 clear_bit(NETLINK_CONGESTED, &nlk->state);
284 if (!test_bit(NETLINK_CONGESTED, &nlk->state))
285 wake_up_interruptible(&nlk->wait);
288 #ifdef CONFIG_NETLINK_MMAP
289 static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
291 return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
294 static bool netlink_rx_is_mmaped(struct sock *sk)
296 return nlk_sk(sk)->rx_ring.pg_vec != NULL;
299 static bool netlink_tx_is_mmaped(struct sock *sk)
301 return nlk_sk(sk)->tx_ring.pg_vec != NULL;
304 static __pure struct page *pgvec_to_page(const void *addr)
306 if (is_vmalloc_addr(addr))
307 return vmalloc_to_page(addr);
309 return virt_to_page(addr);
312 static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
316 for (i = 0; i < len; i++) {
317 if (pg_vec[i] != NULL) {
318 if (is_vmalloc_addr(pg_vec[i]))
321 free_pages((unsigned long)pg_vec[i], order);
327 static void *alloc_one_pg_vec_page(unsigned long order)
330 gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
331 __GFP_NOWARN | __GFP_NORETRY;
333 buffer = (void *)__get_free_pages(gfp_flags, order);
337 buffer = vzalloc((1 << order) * PAGE_SIZE);
341 gfp_flags &= ~__GFP_NORETRY;
342 return (void *)__get_free_pages(gfp_flags, order);
345 static void **alloc_pg_vec(struct netlink_sock *nlk,
346 struct nl_mmap_req *req, unsigned int order)
348 unsigned int block_nr = req->nm_block_nr;
352 pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
356 for (i = 0; i < block_nr; i++) {
357 pg_vec[i] = alloc_one_pg_vec_page(order);
358 if (pg_vec[i] == NULL)
364 free_pg_vec(pg_vec, order, block_nr);
368 static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
369 bool closing, bool tx_ring)
371 struct netlink_sock *nlk = nlk_sk(sk);
372 struct netlink_ring *ring;
373 struct sk_buff_head *queue;
374 void **pg_vec = NULL;
375 unsigned int order = 0;
378 ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
379 queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
382 if (atomic_read(&nlk->mapped))
384 if (atomic_read(&ring->pending))
388 if (req->nm_block_nr) {
389 if (ring->pg_vec != NULL)
392 if ((int)req->nm_block_size <= 0)
394 if (!PAGE_ALIGNED(req->nm_block_size))
396 if (req->nm_frame_size < NL_MMAP_HDRLEN)
398 if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
401 ring->frames_per_block = req->nm_block_size /
403 if (ring->frames_per_block == 0)
405 if (ring->frames_per_block * req->nm_block_nr !=
409 order = get_order(req->nm_block_size);
410 pg_vec = alloc_pg_vec(nlk, req, order);
414 if (req->nm_frame_nr)
419 mutex_lock(&nlk->pg_vec_lock);
420 if (closing || atomic_read(&nlk->mapped) == 0) {
422 spin_lock_bh(&queue->lock);
424 ring->frame_max = req->nm_frame_nr - 1;
426 ring->frame_size = req->nm_frame_size;
427 ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
429 swap(ring->pg_vec_len, req->nm_block_nr);
430 swap(ring->pg_vec_order, order);
431 swap(ring->pg_vec, pg_vec);
433 __skb_queue_purge(queue);
434 spin_unlock_bh(&queue->lock);
436 WARN_ON(atomic_read(&nlk->mapped));
438 mutex_unlock(&nlk->pg_vec_lock);
441 free_pg_vec(pg_vec, order, req->nm_block_nr);
445 static void netlink_mm_open(struct vm_area_struct *vma)
447 struct file *file = vma->vm_file;
448 struct socket *sock = file->private_data;
449 struct sock *sk = sock->sk;
452 atomic_inc(&nlk_sk(sk)->mapped);
455 static void netlink_mm_close(struct vm_area_struct *vma)
457 struct file *file = vma->vm_file;
458 struct socket *sock = file->private_data;
459 struct sock *sk = sock->sk;
462 atomic_dec(&nlk_sk(sk)->mapped);
465 static const struct vm_operations_struct netlink_mmap_ops = {
466 .open = netlink_mm_open,
467 .close = netlink_mm_close,
470 static int netlink_mmap(struct file *file, struct socket *sock,
471 struct vm_area_struct *vma)
473 struct sock *sk = sock->sk;
474 struct netlink_sock *nlk = nlk_sk(sk);
475 struct netlink_ring *ring;
476 unsigned long start, size, expected;
483 mutex_lock(&nlk->pg_vec_lock);
486 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
487 if (ring->pg_vec == NULL)
489 expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
495 size = vma->vm_end - vma->vm_start;
496 if (size != expected)
499 start = vma->vm_start;
500 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
501 if (ring->pg_vec == NULL)
504 for (i = 0; i < ring->pg_vec_len; i++) {
506 void *kaddr = ring->pg_vec[i];
509 for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
510 page = pgvec_to_page(kaddr);
511 err = vm_insert_page(vma, start, page);
520 atomic_inc(&nlk->mapped);
521 vma->vm_ops = &netlink_mmap_ops;
524 mutex_unlock(&nlk->pg_vec_lock);
528 static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
530 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
531 struct page *p_start, *p_end;
533 /* First page is flushed through netlink_{get,set}_status */
534 p_start = pgvec_to_page(hdr + PAGE_SIZE);
535 p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
536 while (p_start <= p_end) {
537 flush_dcache_page(p_start);
543 static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
546 flush_dcache_page(pgvec_to_page(hdr));
547 return hdr->nm_status;
550 static void netlink_set_status(struct nl_mmap_hdr *hdr,
551 enum nl_mmap_status status)
553 hdr->nm_status = status;
554 flush_dcache_page(pgvec_to_page(hdr));
558 static struct nl_mmap_hdr *
559 __netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
561 unsigned int pg_vec_pos, frame_off;
563 pg_vec_pos = pos / ring->frames_per_block;
564 frame_off = pos % ring->frames_per_block;
566 return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
569 static struct nl_mmap_hdr *
570 netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
571 enum nl_mmap_status status)
573 struct nl_mmap_hdr *hdr;
575 hdr = __netlink_lookup_frame(ring, pos);
576 if (netlink_get_status(hdr) != status)
582 static struct nl_mmap_hdr *
583 netlink_current_frame(const struct netlink_ring *ring,
584 enum nl_mmap_status status)
586 return netlink_lookup_frame(ring, ring->head, status);
589 static struct nl_mmap_hdr *
590 netlink_previous_frame(const struct netlink_ring *ring,
591 enum nl_mmap_status status)
595 prev = ring->head ? ring->head - 1 : ring->frame_max;
596 return netlink_lookup_frame(ring, prev, status);
599 static void netlink_increment_head(struct netlink_ring *ring)
601 ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
604 static void netlink_forward_ring(struct netlink_ring *ring)
606 unsigned int head = ring->head, pos = head;
607 const struct nl_mmap_hdr *hdr;
610 hdr = __netlink_lookup_frame(ring, pos);
611 if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
613 if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
615 netlink_increment_head(ring);
616 } while (ring->head != head);
619 static bool netlink_dump_space(struct netlink_sock *nlk)
621 struct netlink_ring *ring = &nlk->rx_ring;
622 struct nl_mmap_hdr *hdr;
625 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
629 n = ring->head + ring->frame_max / 2;
630 if (n > ring->frame_max)
631 n -= ring->frame_max;
633 hdr = __netlink_lookup_frame(ring, n);
635 return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
638 static unsigned int netlink_poll(struct file *file, struct socket *sock,
641 struct sock *sk = sock->sk;
642 struct netlink_sock *nlk = nlk_sk(sk);
646 if (nlk->rx_ring.pg_vec != NULL) {
647 /* Memory mapped sockets don't call recvmsg(), so flow control
648 * for dumps is performed here. A dump is allowed to continue
649 * if at least half the ring is unused.
651 while (nlk->cb_running && netlink_dump_space(nlk)) {
652 err = netlink_dump(sk);
655 sk->sk_error_report(sk);
659 netlink_rcv_wake(sk);
662 mask = datagram_poll(file, sock, wait);
664 spin_lock_bh(&sk->sk_receive_queue.lock);
665 if (nlk->rx_ring.pg_vec) {
666 netlink_forward_ring(&nlk->rx_ring);
667 if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
668 mask |= POLLIN | POLLRDNORM;
670 spin_unlock_bh(&sk->sk_receive_queue.lock);
672 spin_lock_bh(&sk->sk_write_queue.lock);
673 if (nlk->tx_ring.pg_vec) {
674 if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
675 mask |= POLLOUT | POLLWRNORM;
677 spin_unlock_bh(&sk->sk_write_queue.lock);
682 static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
684 return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
687 static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
688 struct netlink_ring *ring,
689 struct nl_mmap_hdr *hdr)
694 size = ring->frame_size - NL_MMAP_HDRLEN;
695 data = (void *)hdr + NL_MMAP_HDRLEN;
699 skb_reset_tail_pointer(skb);
700 skb->end = skb->tail + size;
703 skb->destructor = netlink_skb_destructor;
704 NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
705 NETLINK_CB(skb).sk = sk;
708 static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
709 u32 dst_portid, u32 dst_group,
710 struct sock_iocb *siocb)
712 struct netlink_sock *nlk = nlk_sk(sk);
713 struct netlink_ring *ring;
714 struct nl_mmap_hdr *hdr;
718 int err = 0, len = 0;
720 /* Netlink messages are validated by the receiver before processing.
721 * In order to avoid userspace changing the contents of the message
722 * after validation, the socket and the ring may only be used by a
723 * single process, otherwise we fall back to copying.
725 if (atomic_long_read(&sk->sk_socket->file->f_count) > 1 ||
726 atomic_read(&nlk->mapped) > 1)
729 mutex_lock(&nlk->pg_vec_lock);
731 ring = &nlk->tx_ring;
732 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
735 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
737 if (!(msg->msg_flags & MSG_DONTWAIT) &&
738 atomic_read(&nlk->tx_ring.pending))
742 if (hdr->nm_len > maxlen) {
747 netlink_frame_flush_dcache(hdr);
749 if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
750 skb = alloc_skb_head(GFP_KERNEL);
756 netlink_ring_setup_skb(skb, sk, ring, hdr);
757 NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
758 __skb_put(skb, hdr->nm_len);
759 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
760 atomic_inc(&ring->pending);
762 skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
767 __skb_put(skb, hdr->nm_len);
768 memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
769 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
772 netlink_increment_head(ring);
774 NETLINK_CB(skb).portid = nlk->portid;
775 NETLINK_CB(skb).dst_group = dst_group;
776 NETLINK_CB(skb).creds = siocb->scm->creds;
778 err = security_netlink_send(sk, skb);
784 if (unlikely(dst_group)) {
785 atomic_inc(&skb->users);
786 netlink_broadcast(sk, skb, dst_portid, dst_group,
789 err = netlink_unicast(sk, skb, dst_portid,
790 msg->msg_flags & MSG_DONTWAIT);
795 } while (hdr != NULL ||
796 (!(msg->msg_flags & MSG_DONTWAIT) &&
797 atomic_read(&nlk->tx_ring.pending)));
802 mutex_unlock(&nlk->pg_vec_lock);
806 static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
808 struct nl_mmap_hdr *hdr;
810 hdr = netlink_mmap_hdr(skb);
811 hdr->nm_len = skb->len;
812 hdr->nm_group = NETLINK_CB(skb).dst_group;
813 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
814 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
815 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
816 netlink_frame_flush_dcache(hdr);
817 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
819 NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
823 static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
825 struct netlink_sock *nlk = nlk_sk(sk);
826 struct netlink_ring *ring = &nlk->rx_ring;
827 struct nl_mmap_hdr *hdr;
829 spin_lock_bh(&sk->sk_receive_queue.lock);
830 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
832 spin_unlock_bh(&sk->sk_receive_queue.lock);
837 netlink_increment_head(ring);
838 __skb_queue_tail(&sk->sk_receive_queue, skb);
839 spin_unlock_bh(&sk->sk_receive_queue.lock);
841 hdr->nm_len = skb->len;
842 hdr->nm_group = NETLINK_CB(skb).dst_group;
843 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
844 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
845 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
846 netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
849 #else /* CONFIG_NETLINK_MMAP */
850 #define netlink_skb_is_mmaped(skb) false
851 #define netlink_rx_is_mmaped(sk) false
852 #define netlink_tx_is_mmaped(sk) false
853 #define netlink_mmap sock_no_mmap
854 #define netlink_poll datagram_poll
855 #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
856 #endif /* CONFIG_NETLINK_MMAP */
858 static void netlink_skb_destructor(struct sk_buff *skb)
860 #ifdef CONFIG_NETLINK_MMAP
861 struct nl_mmap_hdr *hdr;
862 struct netlink_ring *ring;
865 /* If a packet from the kernel to userspace was freed because of an
866 * error without being delivered to userspace, the kernel must reset
867 * the status. In the direction userspace to kernel, the status is
868 * always reset here after the packet was processed and freed.
870 if (netlink_skb_is_mmaped(skb)) {
871 hdr = netlink_mmap_hdr(skb);
872 sk = NETLINK_CB(skb).sk;
874 if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
875 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
876 ring = &nlk_sk(sk)->tx_ring;
878 if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
880 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
882 ring = &nlk_sk(sk)->rx_ring;
885 WARN_ON(atomic_read(&ring->pending) == 0);
886 atomic_dec(&ring->pending);
892 if (is_vmalloc_addr(skb->head)) {
894 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
903 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
905 WARN_ON(skb->sk != NULL);
907 skb->destructor = netlink_skb_destructor;
908 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
909 sk_mem_charge(sk, skb->truesize);
912 static void netlink_sock_destruct(struct sock *sk)
914 struct netlink_sock *nlk = nlk_sk(sk);
916 if (nlk->cb_running) {
918 nlk->cb.done(&nlk->cb);
920 module_put(nlk->cb.module);
921 kfree_skb(nlk->cb.skb);
924 skb_queue_purge(&sk->sk_receive_queue);
925 #ifdef CONFIG_NETLINK_MMAP
927 struct nl_mmap_req req;
929 memset(&req, 0, sizeof(req));
930 if (nlk->rx_ring.pg_vec)
931 netlink_set_ring(sk, &req, true, false);
932 memset(&req, 0, sizeof(req));
933 if (nlk->tx_ring.pg_vec)
934 netlink_set_ring(sk, &req, true, true);
936 #endif /* CONFIG_NETLINK_MMAP */
938 if (!sock_flag(sk, SOCK_DEAD)) {
939 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
943 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
944 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
945 WARN_ON(nlk_sk(sk)->groups);
948 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
949 * SMP. Look, when several writers sleep and reader wakes them up, all but one
950 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
951 * this, _but_ remember, it adds useless work on UP machines.
954 void netlink_table_grab(void)
955 __acquires(nl_table_lock)
959 write_lock_irq(&nl_table_lock);
961 if (atomic_read(&nl_table_users)) {
962 DECLARE_WAITQUEUE(wait, current);
964 add_wait_queue_exclusive(&nl_table_wait, &wait);
966 set_current_state(TASK_UNINTERRUPTIBLE);
967 if (atomic_read(&nl_table_users) == 0)
969 write_unlock_irq(&nl_table_lock);
971 write_lock_irq(&nl_table_lock);
974 __set_current_state(TASK_RUNNING);
975 remove_wait_queue(&nl_table_wait, &wait);
979 void netlink_table_ungrab(void)
980 __releases(nl_table_lock)
982 write_unlock_irq(&nl_table_lock);
983 wake_up(&nl_table_wait);
987 netlink_lock_table(void)
989 /* read_lock() synchronizes us to netlink_table_grab */
991 read_lock(&nl_table_lock);
992 atomic_inc(&nl_table_users);
993 read_unlock(&nl_table_lock);
997 netlink_unlock_table(void)
999 if (atomic_dec_and_test(&nl_table_users))
1000 wake_up(&nl_table_wait);
1003 struct netlink_compare_arg
1009 static bool netlink_compare(void *ptr, void *arg)
1011 struct netlink_compare_arg *x = arg;
1012 struct sock *sk = ptr;
1014 return nlk_sk(sk)->portid == x->portid &&
1015 net_eq(sock_net(sk), x->net);
1018 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
1021 struct netlink_compare_arg arg = {
1027 hash = rhashtable_hashfn(&table->hash, &portid, sizeof(portid));
1029 return rhashtable_lookup_compare(&table->hash, hash,
1030 &netlink_compare, &arg);
1033 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
1035 struct netlink_table *table = &nl_table[protocol];
1038 read_lock(&nl_table_lock);
1040 sk = __netlink_lookup(table, portid, net);
1044 read_unlock(&nl_table_lock);
1049 static const struct proto_ops netlink_ops;
1052 netlink_update_listeners(struct sock *sk)
1054 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1057 struct listeners *listeners;
1059 listeners = nl_deref_protected(tbl->listeners);
1063 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
1065 sk_for_each_bound(sk, &tbl->mc_list) {
1066 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
1067 mask |= nlk_sk(sk)->groups[i];
1069 listeners->masks[i] = mask;
1071 /* this function is only called with the netlink table "grabbed", which
1072 * makes sure updates are visible before bind or setsockopt return. */
1075 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
1077 struct netlink_table *table = &nl_table[sk->sk_protocol];
1078 int err = -EADDRINUSE;
1080 mutex_lock(&nl_sk_hash_lock);
1081 if (__netlink_lookup(table, portid, net))
1085 if (nlk_sk(sk)->portid)
1089 if (BITS_PER_LONG > 32 && unlikely(table->hash.nelems >= UINT_MAX))
1092 nlk_sk(sk)->portid = portid;
1094 rhashtable_insert(&table->hash, &nlk_sk(sk)->node);
1097 mutex_unlock(&nl_sk_hash_lock);
1101 static void netlink_remove(struct sock *sk)
1103 struct netlink_table *table;
1105 mutex_lock(&nl_sk_hash_lock);
1106 table = &nl_table[sk->sk_protocol];
1107 if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node)) {
1108 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
1111 mutex_unlock(&nl_sk_hash_lock);
1113 netlink_table_grab();
1114 if (nlk_sk(sk)->subscriptions)
1115 __sk_del_bind_node(sk);
1116 netlink_table_ungrab();
1119 static struct proto netlink_proto = {
1121 .owner = THIS_MODULE,
1122 .obj_size = sizeof(struct netlink_sock),
1125 static int __netlink_create(struct net *net, struct socket *sock,
1126 struct mutex *cb_mutex, int protocol)
1129 struct netlink_sock *nlk;
1131 sock->ops = &netlink_ops;
1133 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
1137 sock_init_data(sock, sk);
1141 nlk->cb_mutex = cb_mutex;
1143 nlk->cb_mutex = &nlk->cb_def_mutex;
1144 mutex_init(nlk->cb_mutex);
1146 init_waitqueue_head(&nlk->wait);
1147 #ifdef CONFIG_NETLINK_MMAP
1148 mutex_init(&nlk->pg_vec_lock);
1151 sk->sk_destruct = netlink_sock_destruct;
1152 sk->sk_protocol = protocol;
1156 static int netlink_create(struct net *net, struct socket *sock, int protocol,
1159 struct module *module = NULL;
1160 struct mutex *cb_mutex;
1161 struct netlink_sock *nlk;
1162 int (*bind)(int group);
1163 void (*unbind)(int group);
1166 sock->state = SS_UNCONNECTED;
1168 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1169 return -ESOCKTNOSUPPORT;
1171 if (protocol < 0 || protocol >= MAX_LINKS)
1172 return -EPROTONOSUPPORT;
1174 netlink_lock_table();
1175 #ifdef CONFIG_MODULES
1176 if (!nl_table[protocol].registered) {
1177 netlink_unlock_table();
1178 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
1179 netlink_lock_table();
1182 if (nl_table[protocol].registered &&
1183 try_module_get(nl_table[protocol].module))
1184 module = nl_table[protocol].module;
1186 err = -EPROTONOSUPPORT;
1187 cb_mutex = nl_table[protocol].cb_mutex;
1188 bind = nl_table[protocol].bind;
1189 unbind = nl_table[protocol].unbind;
1190 netlink_unlock_table();
1195 err = __netlink_create(net, sock, cb_mutex, protocol);
1200 sock_prot_inuse_add(net, &netlink_proto, 1);
1203 nlk = nlk_sk(sock->sk);
1204 nlk->module = module;
1205 nlk->netlink_bind = bind;
1206 nlk->netlink_unbind = unbind;
1215 static int netlink_release(struct socket *sock)
1217 struct sock *sk = sock->sk;
1218 struct netlink_sock *nlk;
1228 * OK. Socket is unlinked, any packets that arrive now
1233 wake_up_interruptible_all(&nlk->wait);
1235 skb_queue_purge(&sk->sk_write_queue);
1238 struct netlink_notify n = {
1239 .net = sock_net(sk),
1240 .protocol = sk->sk_protocol,
1241 .portid = nlk->portid,
1243 atomic_notifier_call_chain(&netlink_chain,
1244 NETLINK_URELEASE, &n);
1247 module_put(nlk->module);
1249 netlink_table_grab();
1250 if (netlink_is_kernel(sk)) {
1251 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
1252 if (--nl_table[sk->sk_protocol].registered == 0) {
1253 struct listeners *old;
1255 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
1256 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
1257 kfree_rcu(old, rcu);
1258 nl_table[sk->sk_protocol].module = NULL;
1259 nl_table[sk->sk_protocol].bind = NULL;
1260 nl_table[sk->sk_protocol].unbind = NULL;
1261 nl_table[sk->sk_protocol].flags = 0;
1262 nl_table[sk->sk_protocol].registered = 0;
1264 } else if (nlk->subscriptions) {
1265 netlink_update_listeners(sk);
1267 netlink_table_ungrab();
1273 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
1279 static int netlink_autobind(struct socket *sock)
1281 struct sock *sk = sock->sk;
1282 struct net *net = sock_net(sk);
1283 struct netlink_table *table = &nl_table[sk->sk_protocol];
1284 s32 portid = task_tgid_vnr(current);
1286 static s32 rover = -4097;
1290 netlink_table_grab();
1292 if (__netlink_lookup(table, portid, net)) {
1293 /* Bind collision, search negative portid values. */
1298 netlink_table_ungrab();
1302 netlink_table_ungrab();
1304 err = netlink_insert(sk, net, portid);
1305 if (err == -EADDRINUSE)
1308 /* If 2 threads race to autobind, that is fine. */
1316 * __netlink_ns_capable - General netlink message capability test
1317 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
1318 * @user_ns: The user namespace of the capability to use
1319 * @cap: The capability to use
1321 * Test to see if the opener of the socket we received the message
1322 * from had when the netlink socket was created and the sender of the
1323 * message has has the capability @cap in the user namespace @user_ns.
1325 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
1326 struct user_namespace *user_ns, int cap)
1328 return ((nsp->flags & NETLINK_SKB_DST) ||
1329 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
1330 ns_capable(user_ns, cap);
1332 EXPORT_SYMBOL(__netlink_ns_capable);
1335 * netlink_ns_capable - General netlink message capability test
1336 * @skb: socket buffer holding a netlink command from userspace
1337 * @user_ns: The user namespace of the capability to use
1338 * @cap: The capability to use
1340 * Test to see if the opener of the socket we received the message
1341 * from had when the netlink socket was created and the sender of the
1342 * message has has the capability @cap in the user namespace @user_ns.
1344 bool netlink_ns_capable(const struct sk_buff *skb,
1345 struct user_namespace *user_ns, int cap)
1347 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
1349 EXPORT_SYMBOL(netlink_ns_capable);
1352 * netlink_capable - Netlink global message capability test
1353 * @skb: socket buffer holding a netlink command from userspace
1354 * @cap: The capability to use
1356 * Test to see if the opener of the socket we received the message
1357 * from had when the netlink socket was created and the sender of the
1358 * message has has the capability @cap in all user namespaces.
1360 bool netlink_capable(const struct sk_buff *skb, int cap)
1362 return netlink_ns_capable(skb, &init_user_ns, cap);
1364 EXPORT_SYMBOL(netlink_capable);
1367 * netlink_net_capable - Netlink network namespace message capability test
1368 * @skb: socket buffer holding a netlink command from userspace
1369 * @cap: The capability to use
1371 * Test to see if the opener of the socket we received the message
1372 * from had when the netlink socket was created and the sender of the
1373 * message has has the capability @cap over the network namespace of
1374 * the socket we received the message from.
1376 bool netlink_net_capable(const struct sk_buff *skb, int cap)
1378 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
1380 EXPORT_SYMBOL(netlink_net_capable);
1382 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
1384 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
1385 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
1389 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
1391 struct netlink_sock *nlk = nlk_sk(sk);
1393 if (nlk->subscriptions && !subscriptions)
1394 __sk_del_bind_node(sk);
1395 else if (!nlk->subscriptions && subscriptions)
1396 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
1397 nlk->subscriptions = subscriptions;
1400 static int netlink_realloc_groups(struct sock *sk)
1402 struct netlink_sock *nlk = nlk_sk(sk);
1403 unsigned int groups;
1404 unsigned long *new_groups;
1407 netlink_table_grab();
1409 groups = nl_table[sk->sk_protocol].groups;
1410 if (!nl_table[sk->sk_protocol].registered) {
1415 if (nlk->ngroups >= groups)
1418 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
1419 if (new_groups == NULL) {
1423 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
1424 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
1426 nlk->groups = new_groups;
1427 nlk->ngroups = groups;
1429 netlink_table_ungrab();
1433 static void netlink_unbind(int group, long unsigned int groups,
1434 struct netlink_sock *nlk)
1438 if (!nlk->netlink_unbind)
1441 for (undo = 0; undo < group; undo++)
1442 if (test_bit(undo, &groups))
1443 nlk->netlink_unbind(undo);
1446 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1449 struct sock *sk = sock->sk;
1450 struct net *net = sock_net(sk);
1451 struct netlink_sock *nlk = nlk_sk(sk);
1452 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1454 long unsigned int groups = nladdr->nl_groups;
1456 if (addr_len < sizeof(struct sockaddr_nl))
1459 if (nladdr->nl_family != AF_NETLINK)
1462 /* Only superuser is allowed to listen multicasts */
1464 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1466 err = netlink_realloc_groups(sk);
1472 if (nladdr->nl_pid != nlk->portid)
1475 if (nlk->netlink_bind && groups) {
1478 for (group = 0; group < nlk->ngroups; group++) {
1479 if (!test_bit(group, &groups))
1481 err = nlk->netlink_bind(group);
1484 netlink_unbind(group, groups, nlk);
1490 err = nladdr->nl_pid ?
1491 netlink_insert(sk, net, nladdr->nl_pid) :
1492 netlink_autobind(sock);
1494 netlink_unbind(nlk->ngroups, groups, nlk);
1499 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1502 netlink_table_grab();
1503 netlink_update_subscriptions(sk, nlk->subscriptions +
1505 hweight32(nlk->groups[0]));
1506 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1507 netlink_update_listeners(sk);
1508 netlink_table_ungrab();
1513 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1514 int alen, int flags)
1517 struct sock *sk = sock->sk;
1518 struct netlink_sock *nlk = nlk_sk(sk);
1519 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1521 if (alen < sizeof(addr->sa_family))
1524 if (addr->sa_family == AF_UNSPEC) {
1525 sk->sk_state = NETLINK_UNCONNECTED;
1526 nlk->dst_portid = 0;
1530 if (addr->sa_family != AF_NETLINK)
1533 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1534 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1538 err = netlink_autobind(sock);
1541 sk->sk_state = NETLINK_CONNECTED;
1542 nlk->dst_portid = nladdr->nl_pid;
1543 nlk->dst_group = ffs(nladdr->nl_groups);
1549 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1550 int *addr_len, int peer)
1552 struct sock *sk = sock->sk;
1553 struct netlink_sock *nlk = nlk_sk(sk);
1554 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1556 nladdr->nl_family = AF_NETLINK;
1558 *addr_len = sizeof(*nladdr);
1561 nladdr->nl_pid = nlk->dst_portid;
1562 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1564 nladdr->nl_pid = nlk->portid;
1565 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1570 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1573 struct netlink_sock *nlk;
1575 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1577 return ERR_PTR(-ECONNREFUSED);
1579 /* Don't bother queuing skb if kernel socket has no input function */
1581 if (sock->sk_state == NETLINK_CONNECTED &&
1582 nlk->dst_portid != nlk_sk(ssk)->portid) {
1584 return ERR_PTR(-ECONNREFUSED);
1589 struct sock *netlink_getsockbyfilp(struct file *filp)
1591 struct inode *inode = file_inode(filp);
1594 if (!S_ISSOCK(inode->i_mode))
1595 return ERR_PTR(-ENOTSOCK);
1597 sock = SOCKET_I(inode)->sk;
1598 if (sock->sk_family != AF_NETLINK)
1599 return ERR_PTR(-EINVAL);
1605 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1608 struct sk_buff *skb;
1611 if (size <= NLMSG_GOODSIZE || broadcast)
1612 return alloc_skb(size, GFP_KERNEL);
1614 size = SKB_DATA_ALIGN(size) +
1615 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1617 data = vmalloc(size);
1621 skb = build_skb(data, size);
1626 skb->destructor = netlink_skb_destructor;
1633 * Attach a skb to a netlink socket.
1634 * The caller must hold a reference to the destination socket. On error, the
1635 * reference is dropped. The skb is not send to the destination, just all
1636 * all error checks are performed and memory in the queue is reserved.
1638 * < 0: error. skb freed, reference to sock dropped.
1640 * 1: repeat lookup - reference dropped while waiting for socket memory.
1642 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1643 long *timeo, struct sock *ssk)
1645 struct netlink_sock *nlk;
1649 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1650 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1651 !netlink_skb_is_mmaped(skb)) {
1652 DECLARE_WAITQUEUE(wait, current);
1654 if (!ssk || netlink_is_kernel(ssk))
1655 netlink_overrun(sk);
1661 __set_current_state(TASK_INTERRUPTIBLE);
1662 add_wait_queue(&nlk->wait, &wait);
1664 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1665 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1666 !sock_flag(sk, SOCK_DEAD))
1667 *timeo = schedule_timeout(*timeo);
1669 __set_current_state(TASK_RUNNING);
1670 remove_wait_queue(&nlk->wait, &wait);
1673 if (signal_pending(current)) {
1675 return sock_intr_errno(*timeo);
1679 netlink_skb_set_owner_r(skb, sk);
1683 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1687 netlink_deliver_tap(skb);
1689 #ifdef CONFIG_NETLINK_MMAP
1690 if (netlink_skb_is_mmaped(skb))
1691 netlink_queue_mmaped_skb(sk, skb);
1692 else if (netlink_rx_is_mmaped(sk))
1693 netlink_ring_set_copied(sk, skb);
1695 #endif /* CONFIG_NETLINK_MMAP */
1696 skb_queue_tail(&sk->sk_receive_queue, skb);
1697 sk->sk_data_ready(sk);
1701 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1703 int len = __netlink_sendskb(sk, skb);
1709 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1715 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1719 WARN_ON(skb->sk != NULL);
1720 if (netlink_skb_is_mmaped(skb))
1723 delta = skb->end - skb->tail;
1724 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1727 if (skb_shared(skb)) {
1728 struct sk_buff *nskb = skb_clone(skb, allocation);
1735 if (!pskb_expand_head(skb, 0, -delta, allocation))
1736 skb->truesize -= delta;
1741 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1745 struct netlink_sock *nlk = nlk_sk(sk);
1747 ret = -ECONNREFUSED;
1748 if (nlk->netlink_rcv != NULL) {
1750 netlink_skb_set_owner_r(skb, sk);
1751 NETLINK_CB(skb).sk = ssk;
1752 netlink_deliver_tap_kernel(sk, ssk, skb);
1753 nlk->netlink_rcv(skb);
1762 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1763 u32 portid, int nonblock)
1769 skb = netlink_trim(skb, gfp_any());
1771 timeo = sock_sndtimeo(ssk, nonblock);
1773 sk = netlink_getsockbyportid(ssk, portid);
1778 if (netlink_is_kernel(sk))
1779 return netlink_unicast_kernel(sk, skb, ssk);
1781 if (sk_filter(sk, skb)) {
1788 err = netlink_attachskb(sk, skb, &timeo, ssk);
1794 return netlink_sendskb(sk, skb);
1796 EXPORT_SYMBOL(netlink_unicast);
1798 struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
1799 u32 dst_portid, gfp_t gfp_mask)
1801 #ifdef CONFIG_NETLINK_MMAP
1802 struct sock *sk = NULL;
1803 struct sk_buff *skb;
1804 struct netlink_ring *ring;
1805 struct nl_mmap_hdr *hdr;
1806 unsigned int maxlen;
1808 sk = netlink_getsockbyportid(ssk, dst_portid);
1812 ring = &nlk_sk(sk)->rx_ring;
1813 /* fast-path without atomic ops for common case: non-mmaped receiver */
1814 if (ring->pg_vec == NULL)
1817 if (ring->frame_size - NL_MMAP_HDRLEN < size)
1820 skb = alloc_skb_head(gfp_mask);
1824 spin_lock_bh(&sk->sk_receive_queue.lock);
1825 /* check again under lock */
1826 if (ring->pg_vec == NULL)
1829 /* check again under lock */
1830 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
1834 netlink_forward_ring(ring);
1835 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
1838 netlink_ring_setup_skb(skb, sk, ring, hdr);
1839 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
1840 atomic_inc(&ring->pending);
1841 netlink_increment_head(ring);
1843 spin_unlock_bh(&sk->sk_receive_queue.lock);
1848 spin_unlock_bh(&sk->sk_receive_queue.lock);
1849 netlink_overrun(sk);
1856 spin_unlock_bh(&sk->sk_receive_queue.lock);
1861 return alloc_skb(size, gfp_mask);
1863 EXPORT_SYMBOL_GPL(netlink_alloc_skb);
1865 int netlink_has_listeners(struct sock *sk, unsigned int group)
1868 struct listeners *listeners;
1870 BUG_ON(!netlink_is_kernel(sk));
1873 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1875 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1876 res = test_bit(group - 1, listeners->masks);
1882 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1884 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1886 struct netlink_sock *nlk = nlk_sk(sk);
1888 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1889 !test_bit(NETLINK_CONGESTED, &nlk->state)) {
1890 netlink_skb_set_owner_r(skb, sk);
1891 __netlink_sendskb(sk, skb);
1892 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1897 struct netlink_broadcast_data {
1898 struct sock *exclude_sk;
1903 int delivery_failure;
1907 struct sk_buff *skb, *skb2;
1908 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1912 static void do_one_broadcast(struct sock *sk,
1913 struct netlink_broadcast_data *p)
1915 struct netlink_sock *nlk = nlk_sk(sk);
1918 if (p->exclude_sk == sk)
1921 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1922 !test_bit(p->group - 1, nlk->groups))
1925 if (!net_eq(sock_net(sk), p->net))
1929 netlink_overrun(sk);
1934 if (p->skb2 == NULL) {
1935 if (skb_shared(p->skb)) {
1936 p->skb2 = skb_clone(p->skb, p->allocation);
1938 p->skb2 = skb_get(p->skb);
1940 * skb ownership may have been set when
1941 * delivered to a previous socket.
1943 skb_orphan(p->skb2);
1946 if (p->skb2 == NULL) {
1947 netlink_overrun(sk);
1948 /* Clone failed. Notify ALL listeners. */
1950 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1951 p->delivery_failure = 1;
1952 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1955 } else if (sk_filter(sk, p->skb2)) {
1958 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1959 netlink_overrun(sk);
1960 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1961 p->delivery_failure = 1;
1963 p->congested |= val;
1970 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1971 u32 group, gfp_t allocation,
1972 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1975 struct net *net = sock_net(ssk);
1976 struct netlink_broadcast_data info;
1979 skb = netlink_trim(skb, allocation);
1981 info.exclude_sk = ssk;
1983 info.portid = portid;
1986 info.delivery_failure = 0;
1989 info.allocation = allocation;
1992 info.tx_filter = filter;
1993 info.tx_data = filter_data;
1995 /* While we sleep in clone, do not allow to change socket list */
1997 netlink_lock_table();
1999 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2000 do_one_broadcast(sk, &info);
2004 netlink_unlock_table();
2006 if (info.delivery_failure) {
2007 kfree_skb(info.skb2);
2010 consume_skb(info.skb2);
2012 if (info.delivered) {
2013 if (info.congested && (allocation & __GFP_WAIT))
2019 EXPORT_SYMBOL(netlink_broadcast_filtered);
2021 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
2022 u32 group, gfp_t allocation)
2024 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
2027 EXPORT_SYMBOL(netlink_broadcast);
2029 struct netlink_set_err_data {
2030 struct sock *exclude_sk;
2036 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
2038 struct netlink_sock *nlk = nlk_sk(sk);
2041 if (sk == p->exclude_sk)
2044 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
2047 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
2048 !test_bit(p->group - 1, nlk->groups))
2051 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
2056 sk->sk_err = p->code;
2057 sk->sk_error_report(sk);
2063 * netlink_set_err - report error to broadcast listeners
2064 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2065 * @portid: the PORTID of a process that we want to skip (if any)
2066 * @group: the broadcast group that will notice the error
2067 * @code: error code, must be negative (as usual in kernelspace)
2069 * This function returns the number of broadcast listeners that have set the
2070 * NETLINK_RECV_NO_ENOBUFS socket option.
2072 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
2074 struct netlink_set_err_data info;
2078 info.exclude_sk = ssk;
2079 info.portid = portid;
2081 /* sk->sk_err wants a positive error value */
2084 read_lock(&nl_table_lock);
2086 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2087 ret += do_one_set_err(sk, &info);
2089 read_unlock(&nl_table_lock);
2092 EXPORT_SYMBOL(netlink_set_err);
2094 /* must be called with netlink table grabbed */
2095 static void netlink_update_socket_mc(struct netlink_sock *nlk,
2099 int old, new = !!is_new, subscriptions;
2101 old = test_bit(group - 1, nlk->groups);
2102 subscriptions = nlk->subscriptions - old + new;
2104 __set_bit(group - 1, nlk->groups);
2106 __clear_bit(group - 1, nlk->groups);
2107 netlink_update_subscriptions(&nlk->sk, subscriptions);
2108 netlink_update_listeners(&nlk->sk);
2111 static int netlink_setsockopt(struct socket *sock, int level, int optname,
2112 char __user *optval, unsigned int optlen)
2114 struct sock *sk = sock->sk;
2115 struct netlink_sock *nlk = nlk_sk(sk);
2116 unsigned int val = 0;
2119 if (level != SOL_NETLINK)
2120 return -ENOPROTOOPT;
2122 if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
2123 optlen >= sizeof(int) &&
2124 get_user(val, (unsigned int __user *)optval))
2128 case NETLINK_PKTINFO:
2130 nlk->flags |= NETLINK_RECV_PKTINFO;
2132 nlk->flags &= ~NETLINK_RECV_PKTINFO;
2135 case NETLINK_ADD_MEMBERSHIP:
2136 case NETLINK_DROP_MEMBERSHIP: {
2137 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
2139 err = netlink_realloc_groups(sk);
2142 if (!val || val - 1 >= nlk->ngroups)
2144 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
2145 err = nlk->netlink_bind(val);
2149 netlink_table_grab();
2150 netlink_update_socket_mc(nlk, val,
2151 optname == NETLINK_ADD_MEMBERSHIP);
2152 netlink_table_ungrab();
2153 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
2154 nlk->netlink_unbind(val);
2159 case NETLINK_BROADCAST_ERROR:
2161 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
2163 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
2166 case NETLINK_NO_ENOBUFS:
2168 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
2169 clear_bit(NETLINK_CONGESTED, &nlk->state);
2170 wake_up_interruptible(&nlk->wait);
2172 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
2176 #ifdef CONFIG_NETLINK_MMAP
2177 case NETLINK_RX_RING:
2178 case NETLINK_TX_RING: {
2179 struct nl_mmap_req req;
2181 /* Rings might consume more memory than queue limits, require
2184 if (!capable(CAP_NET_ADMIN))
2186 if (optlen < sizeof(req))
2188 if (copy_from_user(&req, optval, sizeof(req)))
2190 err = netlink_set_ring(sk, &req, false,
2191 optname == NETLINK_TX_RING);
2194 #endif /* CONFIG_NETLINK_MMAP */
2201 static int netlink_getsockopt(struct socket *sock, int level, int optname,
2202 char __user *optval, int __user *optlen)
2204 struct sock *sk = sock->sk;
2205 struct netlink_sock *nlk = nlk_sk(sk);
2208 if (level != SOL_NETLINK)
2209 return -ENOPROTOOPT;
2211 if (get_user(len, optlen))
2217 case NETLINK_PKTINFO:
2218 if (len < sizeof(int))
2221 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
2222 if (put_user(len, optlen) ||
2223 put_user(val, optval))
2227 case NETLINK_BROADCAST_ERROR:
2228 if (len < sizeof(int))
2231 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
2232 if (put_user(len, optlen) ||
2233 put_user(val, optval))
2237 case NETLINK_NO_ENOBUFS:
2238 if (len < sizeof(int))
2241 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
2242 if (put_user(len, optlen) ||
2243 put_user(val, optval))
2253 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
2255 struct nl_pktinfo info;
2257 info.group = NETLINK_CB(skb).dst_group;
2258 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
2261 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
2262 struct msghdr *msg, size_t len)
2264 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2265 struct sock *sk = sock->sk;
2266 struct netlink_sock *nlk = nlk_sk(sk);
2267 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2270 struct sk_buff *skb;
2272 struct scm_cookie scm;
2273 u32 netlink_skb_flags = 0;
2275 if (msg->msg_flags&MSG_OOB)
2278 if (NULL == siocb->scm)
2281 err = scm_send(sock, msg, siocb->scm, true);
2285 if (msg->msg_namelen) {
2287 if (addr->nl_family != AF_NETLINK)
2289 dst_portid = addr->nl_pid;
2290 dst_group = ffs(addr->nl_groups);
2292 if ((dst_group || dst_portid) &&
2293 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
2295 netlink_skb_flags |= NETLINK_SKB_DST;
2297 dst_portid = nlk->dst_portid;
2298 dst_group = nlk->dst_group;
2302 err = netlink_autobind(sock);
2307 if (netlink_tx_is_mmaped(sk) &&
2308 msg->msg_iov->iov_base == NULL) {
2309 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
2315 if (len > sk->sk_sndbuf - 32)
2318 skb = netlink_alloc_large_skb(len, dst_group);
2322 NETLINK_CB(skb).portid = nlk->portid;
2323 NETLINK_CB(skb).dst_group = dst_group;
2324 NETLINK_CB(skb).creds = siocb->scm->creds;
2325 NETLINK_CB(skb).flags = netlink_skb_flags;
2328 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
2333 err = security_netlink_send(sk, skb);
2340 atomic_inc(&skb->users);
2341 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
2343 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
2346 scm_destroy(siocb->scm);
2350 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
2351 struct msghdr *msg, size_t len,
2354 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2355 struct scm_cookie scm;
2356 struct sock *sk = sock->sk;
2357 struct netlink_sock *nlk = nlk_sk(sk);
2358 int noblock = flags&MSG_DONTWAIT;
2360 struct sk_buff *skb, *data_skb;
2368 skb = skb_recv_datagram(sk, flags, noblock, &err);
2374 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2375 if (unlikely(skb_shinfo(skb)->frag_list)) {
2377 * If this skb has a frag_list, then here that means that we
2378 * will have to use the frag_list skb's data for compat tasks
2379 * and the regular skb's data for normal (non-compat) tasks.
2381 * If we need to send the compat skb, assign it to the
2382 * 'data_skb' variable so that it will be used below for data
2383 * copying. We keep 'skb' for everything else, including
2384 * freeing both later.
2386 if (flags & MSG_CMSG_COMPAT)
2387 data_skb = skb_shinfo(skb)->frag_list;
2391 /* Record the max length of recvmsg() calls for future allocations */
2392 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
2393 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
2396 copied = data_skb->len;
2398 msg->msg_flags |= MSG_TRUNC;
2402 skb_reset_transport_header(data_skb);
2403 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
2405 if (msg->msg_name) {
2406 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2407 addr->nl_family = AF_NETLINK;
2409 addr->nl_pid = NETLINK_CB(skb).portid;
2410 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2411 msg->msg_namelen = sizeof(*addr);
2414 if (nlk->flags & NETLINK_RECV_PKTINFO)
2415 netlink_cmsg_recv_pktinfo(msg, skb);
2417 if (NULL == siocb->scm) {
2418 memset(&scm, 0, sizeof(scm));
2421 siocb->scm->creds = *NETLINK_CREDS(skb);
2422 if (flags & MSG_TRUNC)
2423 copied = data_skb->len;
2425 skb_free_datagram(sk, skb);
2427 if (nlk->cb_running &&
2428 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2429 ret = netlink_dump(sk);
2432 sk->sk_error_report(sk);
2436 scm_recv(sock, msg, siocb->scm, flags);
2438 netlink_rcv_wake(sk);
2439 return err ? : copied;
2442 static void netlink_data_ready(struct sock *sk)
2448 * We export these functions to other modules. They provide a
2449 * complete set of kernel non-blocking support for message
2454 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2455 struct netlink_kernel_cfg *cfg)
2457 struct socket *sock;
2459 struct netlink_sock *nlk;
2460 struct listeners *listeners = NULL;
2461 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2462 unsigned int groups;
2466 if (unit < 0 || unit >= MAX_LINKS)
2469 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2473 * We have to just have a reference on the net from sk, but don't
2474 * get_net it. Besides, we cannot get and then put the net here.
2475 * So we create one inside init_net and the move it to net.
2478 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
2479 goto out_sock_release_nosk;
2482 sk_change_net(sk, net);
2484 if (!cfg || cfg->groups < 32)
2487 groups = cfg->groups;
2489 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2491 goto out_sock_release;
2493 sk->sk_data_ready = netlink_data_ready;
2494 if (cfg && cfg->input)
2495 nlk_sk(sk)->netlink_rcv = cfg->input;
2497 if (netlink_insert(sk, net, 0))
2498 goto out_sock_release;
2501 nlk->flags |= NETLINK_KERNEL_SOCKET;
2503 netlink_table_grab();
2504 if (!nl_table[unit].registered) {
2505 nl_table[unit].groups = groups;
2506 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2507 nl_table[unit].cb_mutex = cb_mutex;
2508 nl_table[unit].module = module;
2510 nl_table[unit].bind = cfg->bind;
2511 nl_table[unit].unbind = cfg->unbind;
2512 nl_table[unit].flags = cfg->flags;
2514 nl_table[unit].compare = cfg->compare;
2516 nl_table[unit].registered = 1;
2519 nl_table[unit].registered++;
2521 netlink_table_ungrab();
2526 netlink_kernel_release(sk);
2529 out_sock_release_nosk:
2533 EXPORT_SYMBOL(__netlink_kernel_create);
2536 netlink_kernel_release(struct sock *sk)
2538 sk_release_kernel(sk);
2540 EXPORT_SYMBOL(netlink_kernel_release);
2542 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2544 struct listeners *new, *old;
2545 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2550 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2551 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2554 old = nl_deref_protected(tbl->listeners);
2555 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2556 rcu_assign_pointer(tbl->listeners, new);
2558 kfree_rcu(old, rcu);
2560 tbl->groups = groups;
2566 * netlink_change_ngroups - change number of multicast groups
2568 * This changes the number of multicast groups that are available
2569 * on a certain netlink family. Note that it is not possible to
2570 * change the number of groups to below 32. Also note that it does
2571 * not implicitly call netlink_clear_multicast_users() when the
2572 * number of groups is reduced.
2574 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2575 * @groups: The new number of groups.
2577 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2581 netlink_table_grab();
2582 err = __netlink_change_ngroups(sk, groups);
2583 netlink_table_ungrab();
2588 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2591 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2593 sk_for_each_bound(sk, &tbl->mc_list)
2594 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2598 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2600 struct nlmsghdr *nlh;
2601 int size = nlmsg_msg_size(len);
2603 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2604 nlh->nlmsg_type = type;
2605 nlh->nlmsg_len = size;
2606 nlh->nlmsg_flags = flags;
2607 nlh->nlmsg_pid = portid;
2608 nlh->nlmsg_seq = seq;
2609 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2610 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2613 EXPORT_SYMBOL(__nlmsg_put);
2616 * It looks a bit ugly.
2617 * It would be better to create kernel thread.
2620 static int netlink_dump(struct sock *sk)
2622 struct netlink_sock *nlk = nlk_sk(sk);
2623 struct netlink_callback *cb;
2624 struct sk_buff *skb = NULL;
2625 struct nlmsghdr *nlh;
2626 int len, err = -ENOBUFS;
2629 mutex_lock(nlk->cb_mutex);
2630 if (!nlk->cb_running) {
2636 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2638 if (!netlink_rx_is_mmaped(sk) &&
2639 atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2642 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2643 * required, but it makes sense to _attempt_ a 16K bytes allocation
2644 * to reduce number of system calls on dump operations, if user
2645 * ever provided a big enough buffer.
2647 if (alloc_size < nlk->max_recvmsg_len) {
2648 skb = netlink_alloc_skb(sk,
2649 nlk->max_recvmsg_len,
2654 /* available room should be exact amount to avoid MSG_TRUNC */
2656 skb_reserve(skb, skb_tailroom(skb) -
2657 nlk->max_recvmsg_len);
2660 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2664 netlink_skb_set_owner_r(skb, sk);
2666 len = cb->dump(skb, cb);
2669 mutex_unlock(nlk->cb_mutex);
2671 if (sk_filter(sk, skb))
2674 __netlink_sendskb(sk, skb);
2678 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2682 nl_dump_check_consistent(cb, nlh);
2684 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2686 if (sk_filter(sk, skb))
2689 __netlink_sendskb(sk, skb);
2694 nlk->cb_running = false;
2695 mutex_unlock(nlk->cb_mutex);
2696 module_put(cb->module);
2697 consume_skb(cb->skb);
2701 mutex_unlock(nlk->cb_mutex);
2706 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2707 const struct nlmsghdr *nlh,
2708 struct netlink_dump_control *control)
2710 struct netlink_callback *cb;
2712 struct netlink_sock *nlk;
2715 /* Memory mapped dump requests need to be copied to avoid looping
2716 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2717 * a reference to the skb.
2719 if (netlink_skb_is_mmaped(skb)) {
2720 skb = skb_copy(skb, GFP_KERNEL);
2724 atomic_inc(&skb->users);
2726 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2728 ret = -ECONNREFUSED;
2733 mutex_lock(nlk->cb_mutex);
2734 /* A dump is in progress... */
2735 if (nlk->cb_running) {
2739 /* add reference of module which cb->dump belongs to */
2740 if (!try_module_get(control->module)) {
2741 ret = -EPROTONOSUPPORT;
2746 memset(cb, 0, sizeof(*cb));
2747 cb->dump = control->dump;
2748 cb->done = control->done;
2750 cb->data = control->data;
2751 cb->module = control->module;
2752 cb->min_dump_alloc = control->min_dump_alloc;
2755 nlk->cb_running = true;
2757 mutex_unlock(nlk->cb_mutex);
2759 ret = netlink_dump(sk);
2765 /* We successfully started a dump, by returning -EINTR we
2766 * signal not to send ACK even if it was requested.
2772 mutex_unlock(nlk->cb_mutex);
2777 EXPORT_SYMBOL(__netlink_dump_start);
2779 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2781 struct sk_buff *skb;
2782 struct nlmsghdr *rep;
2783 struct nlmsgerr *errmsg;
2784 size_t payload = sizeof(*errmsg);
2786 /* error messages get the original request appened */
2788 payload += nlmsg_len(nlh);
2790 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2791 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2795 sk = netlink_lookup(sock_net(in_skb->sk),
2796 in_skb->sk->sk_protocol,
2797 NETLINK_CB(in_skb).portid);
2799 sk->sk_err = ENOBUFS;
2800 sk->sk_error_report(sk);
2806 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2807 NLMSG_ERROR, payload, 0);
2808 errmsg = nlmsg_data(rep);
2809 errmsg->error = err;
2810 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
2811 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2813 EXPORT_SYMBOL(netlink_ack);
2815 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2818 struct nlmsghdr *nlh;
2821 while (skb->len >= nlmsg_total_size(0)) {
2824 nlh = nlmsg_hdr(skb);
2827 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2830 /* Only requests are handled by the kernel */
2831 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2834 /* Skip control messages */
2835 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2843 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2844 netlink_ack(skb, nlh, err);
2847 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2848 if (msglen > skb->len)
2850 skb_pull(skb, msglen);
2855 EXPORT_SYMBOL(netlink_rcv_skb);
2858 * nlmsg_notify - send a notification netlink message
2859 * @sk: netlink socket to use
2860 * @skb: notification message
2861 * @portid: destination netlink portid for reports or 0
2862 * @group: destination multicast group or 0
2863 * @report: 1 to report back, 0 to disable
2864 * @flags: allocation flags
2866 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2867 unsigned int group, int report, gfp_t flags)
2872 int exclude_portid = 0;
2875 atomic_inc(&skb->users);
2876 exclude_portid = portid;
2879 /* errors reported via destination sk->sk_err, but propagate
2880 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2881 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2887 err2 = nlmsg_unicast(sk, skb, portid);
2888 if (!err || err == -ESRCH)
2894 EXPORT_SYMBOL(nlmsg_notify);
2896 #ifdef CONFIG_PROC_FS
2897 struct nl_seq_iter {
2898 struct seq_net_private p;
2903 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
2905 struct nl_seq_iter *iter = seq->private;
2907 struct netlink_sock *nlk;
2911 for (i = 0; i < MAX_LINKS; i++) {
2912 struct rhashtable *ht = &nl_table[i].hash;
2913 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2915 for (j = 0; j < tbl->size; j++) {
2916 rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
2917 s = (struct sock *)nlk;
2919 if (sock_net(s) != seq_file_net(seq))
2933 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2934 __acquires(nl_table_lock) __acquires(RCU)
2936 read_lock(&nl_table_lock);
2938 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2941 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2943 struct rhashtable *ht;
2944 struct netlink_sock *nlk;
2945 struct nl_seq_iter *iter;
2951 if (v == SEQ_START_TOKEN)
2952 return netlink_seq_socket_idx(seq, 0);
2954 net = seq_file_net(seq);
2955 iter = seq->private;
2959 ht = &nl_table[i].hash;
2960 rht_for_each_entry(nlk, nlk->node.next, ht, node)
2961 if (net_eq(sock_net((struct sock *)nlk), net))
2964 j = iter->hash_idx + 1;
2967 const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
2969 for (; j < tbl->size; j++) {
2970 rht_for_each_entry(nlk, tbl->buckets[j], ht, node) {
2971 if (net_eq(sock_net((struct sock *)nlk), net)) {
2980 } while (++i < MAX_LINKS);
2985 static void netlink_seq_stop(struct seq_file *seq, void *v)
2986 __releases(RCU) __releases(nl_table_lock)
2989 read_unlock(&nl_table_lock);
2993 static int netlink_seq_show(struct seq_file *seq, void *v)
2995 if (v == SEQ_START_TOKEN) {
2997 "sk Eth Pid Groups "
2998 "Rmem Wmem Dump Locks Drops Inode\n");
3001 struct netlink_sock *nlk = nlk_sk(s);
3003 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
3007 nlk->groups ? (u32)nlk->groups[0] : 0,
3008 sk_rmem_alloc_get(s),
3009 sk_wmem_alloc_get(s),
3011 atomic_read(&s->sk_refcnt),
3012 atomic_read(&s->sk_drops),
3020 static const struct seq_operations netlink_seq_ops = {
3021 .start = netlink_seq_start,
3022 .next = netlink_seq_next,
3023 .stop = netlink_seq_stop,
3024 .show = netlink_seq_show,
3028 static int netlink_seq_open(struct inode *inode, struct file *file)
3030 return seq_open_net(inode, file, &netlink_seq_ops,
3031 sizeof(struct nl_seq_iter));
3034 static const struct file_operations netlink_seq_fops = {
3035 .owner = THIS_MODULE,
3036 .open = netlink_seq_open,
3038 .llseek = seq_lseek,
3039 .release = seq_release_net,
3044 int netlink_register_notifier(struct notifier_block *nb)
3046 return atomic_notifier_chain_register(&netlink_chain, nb);
3048 EXPORT_SYMBOL(netlink_register_notifier);
3050 int netlink_unregister_notifier(struct notifier_block *nb)
3052 return atomic_notifier_chain_unregister(&netlink_chain, nb);
3054 EXPORT_SYMBOL(netlink_unregister_notifier);
3056 static const struct proto_ops netlink_ops = {
3057 .family = PF_NETLINK,
3058 .owner = THIS_MODULE,
3059 .release = netlink_release,
3060 .bind = netlink_bind,
3061 .connect = netlink_connect,
3062 .socketpair = sock_no_socketpair,
3063 .accept = sock_no_accept,
3064 .getname = netlink_getname,
3065 .poll = netlink_poll,
3066 .ioctl = sock_no_ioctl,
3067 .listen = sock_no_listen,
3068 .shutdown = sock_no_shutdown,
3069 .setsockopt = netlink_setsockopt,
3070 .getsockopt = netlink_getsockopt,
3071 .sendmsg = netlink_sendmsg,
3072 .recvmsg = netlink_recvmsg,
3073 .mmap = netlink_mmap,
3074 .sendpage = sock_no_sendpage,
3077 static const struct net_proto_family netlink_family_ops = {
3078 .family = PF_NETLINK,
3079 .create = netlink_create,
3080 .owner = THIS_MODULE, /* for consistency 8) */
3083 static int __net_init netlink_net_init(struct net *net)
3085 #ifdef CONFIG_PROC_FS
3086 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
3092 static void __net_exit netlink_net_exit(struct net *net)
3094 #ifdef CONFIG_PROC_FS
3095 remove_proc_entry("netlink", net->proc_net);
3099 static void __init netlink_add_usersock_entry(void)
3101 struct listeners *listeners;
3104 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
3106 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3108 netlink_table_grab();
3110 nl_table[NETLINK_USERSOCK].groups = groups;
3111 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
3112 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
3113 nl_table[NETLINK_USERSOCK].registered = 1;
3114 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
3116 netlink_table_ungrab();
3119 static struct pernet_operations __net_initdata netlink_net_ops = {
3120 .init = netlink_net_init,
3121 .exit = netlink_net_exit,
3124 static int __init netlink_proto_init(void)
3127 int err = proto_register(&netlink_proto, 0);
3128 struct rhashtable_params ht_params = {
3129 .head_offset = offsetof(struct netlink_sock, node),
3130 .key_offset = offsetof(struct netlink_sock, portid),
3131 .key_len = sizeof(u32), /* portid */
3132 .hashfn = arch_fast_hash,
3133 .max_shift = 16, /* 64K */
3134 .grow_decision = rht_grow_above_75,
3135 .shrink_decision = rht_shrink_below_30,
3136 #ifdef CONFIG_PROVE_LOCKING
3137 .mutex_is_held = lockdep_nl_sk_hash_is_held,
3144 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
3146 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
3150 for (i = 0; i < MAX_LINKS; i++) {
3151 if (rhashtable_init(&nl_table[i].hash, &ht_params) < 0) {
3153 rhashtable_destroy(&nl_table[i].hash);
3159 INIT_LIST_HEAD(&netlink_tap_all);
3161 netlink_add_usersock_entry();
3163 sock_register(&netlink_family_ops);
3164 register_pernet_subsys(&netlink_net_ops);
3165 /* The netlink device handler may be needed early. */
3170 panic("netlink_init: Cannot allocate nl_table\n");
3173 core_initcall(netlink_proto_init);