2 * NETLINK Kernel-user communication protocol.
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Patrick McHardy <kaber@trash.net>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
14 * added netlink_proto_exit
15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
16 * use nlk_sk, as sk->protinfo is on a diet 8)
17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
18 * - inc module use count of module that owns
19 * the kernel socket in case userspace opens
20 * socket of same protocol
21 * - remove all module support, since netlink is
22 * mandatory if CONFIG_NET=y these days
25 #include <linux/module.h>
27 #include <linux/capability.h>
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/sched.h>
32 #include <linux/errno.h>
33 #include <linux/string.h>
34 #include <linux/stat.h>
35 #include <linux/socket.h>
37 #include <linux/fcntl.h>
38 #include <linux/termios.h>
39 #include <linux/sockios.h>
40 #include <linux/net.h>
42 #include <linux/slab.h>
43 #include <asm/uaccess.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/rtnetlink.h>
47 #include <linux/proc_fs.h>
48 #include <linux/seq_file.h>
49 #include <linux/notifier.h>
50 #include <linux/security.h>
51 #include <linux/jhash.h>
52 #include <linux/jiffies.h>
53 #include <linux/random.h>
54 #include <linux/bitops.h>
56 #include <linux/types.h>
57 #include <linux/audit.h>
58 #include <linux/mutex.h>
59 #include <linux/vmalloc.h>
60 #include <linux/if_arp.h>
61 #include <linux/rhashtable.h>
62 #include <asm/cacheflush.h>
63 #include <linux/hash.h>
64 #include <linux/genetlink.h>
66 #include <net/net_namespace.h>
69 #include <net/netlink.h>
71 #include "af_netlink.h"
75 unsigned long masks
[0];
79 #define NETLINK_CONGESTED 0x0
82 #define NETLINK_KERNEL_SOCKET 0x1
83 #define NETLINK_RECV_PKTINFO 0x2
84 #define NETLINK_BROADCAST_SEND_ERROR 0x4
85 #define NETLINK_RECV_NO_ENOBUFS 0x8
87 static inline int netlink_is_kernel(struct sock
*sk
)
89 return nlk_sk(sk
)->flags
& NETLINK_KERNEL_SOCKET
;
92 struct netlink_table
*nl_table
;
93 EXPORT_SYMBOL_GPL(nl_table
);
95 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait
);
97 static int netlink_dump(struct sock
*sk
);
98 static void netlink_skb_destructor(struct sk_buff
*skb
);
100 /* nl_table locking explained:
101 * Lookup and traversal are protected with an RCU read-side lock. Insertion
102 * and removal are protected with per bucket lock while using RCU list
103 * modification primitives and may run in parallel to RCU protected lookups.
104 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
105 * been acquired * either during or after the socket has been removed from
106 * the list and after an RCU grace period.
108 DEFINE_RWLOCK(nl_table_lock
);
109 EXPORT_SYMBOL_GPL(nl_table_lock
);
110 static atomic_t nl_table_users
= ATOMIC_INIT(0);
112 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
114 static ATOMIC_NOTIFIER_HEAD(netlink_chain
);
116 static DEFINE_SPINLOCK(netlink_tap_lock
);
117 static struct list_head netlink_tap_all __read_mostly
;
119 static const struct rhashtable_params netlink_rhashtable_params
;
121 static inline u32
netlink_group_mask(u32 group
)
123 return group
? 1 << (group
- 1) : 0;
126 int netlink_add_tap(struct netlink_tap
*nt
)
128 if (unlikely(nt
->dev
->type
!= ARPHRD_NETLINK
))
131 spin_lock(&netlink_tap_lock
);
132 list_add_rcu(&nt
->list
, &netlink_tap_all
);
133 spin_unlock(&netlink_tap_lock
);
135 __module_get(nt
->module
);
139 EXPORT_SYMBOL_GPL(netlink_add_tap
);
141 static int __netlink_remove_tap(struct netlink_tap
*nt
)
144 struct netlink_tap
*tmp
;
146 spin_lock(&netlink_tap_lock
);
148 list_for_each_entry(tmp
, &netlink_tap_all
, list
) {
150 list_del_rcu(&nt
->list
);
156 pr_warn("__netlink_remove_tap: %p not found\n", nt
);
158 spin_unlock(&netlink_tap_lock
);
160 if (found
&& nt
->module
)
161 module_put(nt
->module
);
163 return found
? 0 : -ENODEV
;
166 int netlink_remove_tap(struct netlink_tap
*nt
)
170 ret
= __netlink_remove_tap(nt
);
175 EXPORT_SYMBOL_GPL(netlink_remove_tap
);
177 static bool netlink_filter_tap(const struct sk_buff
*skb
)
179 struct sock
*sk
= skb
->sk
;
181 /* We take the more conservative approach and
182 * whitelist socket protocols that may pass.
184 switch (sk
->sk_protocol
) {
186 case NETLINK_USERSOCK
:
187 case NETLINK_SOCK_DIAG
:
190 case NETLINK_FIB_LOOKUP
:
191 case NETLINK_NETFILTER
:
192 case NETLINK_GENERIC
:
199 static int __netlink_deliver_tap_skb(struct sk_buff
*skb
,
200 struct net_device
*dev
)
202 struct sk_buff
*nskb
;
203 struct sock
*sk
= skb
->sk
;
207 nskb
= skb_clone(skb
, GFP_ATOMIC
);
210 nskb
->protocol
= htons((u16
) sk
->sk_protocol
);
211 nskb
->pkt_type
= netlink_is_kernel(sk
) ?
212 PACKET_KERNEL
: PACKET_USER
;
213 skb_reset_network_header(nskb
);
214 ret
= dev_queue_xmit(nskb
);
215 if (unlikely(ret
> 0))
216 ret
= net_xmit_errno(ret
);
223 static void __netlink_deliver_tap(struct sk_buff
*skb
)
226 struct netlink_tap
*tmp
;
228 if (!netlink_filter_tap(skb
))
231 list_for_each_entry_rcu(tmp
, &netlink_tap_all
, list
) {
232 ret
= __netlink_deliver_tap_skb(skb
, tmp
->dev
);
238 static void netlink_deliver_tap(struct sk_buff
*skb
)
242 if (unlikely(!list_empty(&netlink_tap_all
)))
243 __netlink_deliver_tap(skb
);
248 static void netlink_deliver_tap_kernel(struct sock
*dst
, struct sock
*src
,
251 if (!(netlink_is_kernel(dst
) && netlink_is_kernel(src
)))
252 netlink_deliver_tap(skb
);
255 static void netlink_overrun(struct sock
*sk
)
257 struct netlink_sock
*nlk
= nlk_sk(sk
);
259 if (!(nlk
->flags
& NETLINK_RECV_NO_ENOBUFS
)) {
260 if (!test_and_set_bit(NETLINK_CONGESTED
, &nlk_sk(sk
)->state
)) {
261 sk
->sk_err
= ENOBUFS
;
262 sk
->sk_error_report(sk
);
265 atomic_inc(&sk
->sk_drops
);
268 static void netlink_rcv_wake(struct sock
*sk
)
270 struct netlink_sock
*nlk
= nlk_sk(sk
);
272 if (skb_queue_empty(&sk
->sk_receive_queue
))
273 clear_bit(NETLINK_CONGESTED
, &nlk
->state
);
274 if (!test_bit(NETLINK_CONGESTED
, &nlk
->state
))
275 wake_up_interruptible(&nlk
->wait
);
278 #ifdef CONFIG_NETLINK_MMAP
279 static bool netlink_skb_is_mmaped(const struct sk_buff
*skb
)
281 return NETLINK_CB(skb
).flags
& NETLINK_SKB_MMAPED
;
284 static bool netlink_rx_is_mmaped(struct sock
*sk
)
286 return nlk_sk(sk
)->rx_ring
.pg_vec
!= NULL
;
289 static bool netlink_tx_is_mmaped(struct sock
*sk
)
291 return nlk_sk(sk
)->tx_ring
.pg_vec
!= NULL
;
294 static __pure
struct page
*pgvec_to_page(const void *addr
)
296 if (is_vmalloc_addr(addr
))
297 return vmalloc_to_page(addr
);
299 return virt_to_page(addr
);
302 static void free_pg_vec(void **pg_vec
, unsigned int order
, unsigned int len
)
306 for (i
= 0; i
< len
; i
++) {
307 if (pg_vec
[i
] != NULL
) {
308 if (is_vmalloc_addr(pg_vec
[i
]))
311 free_pages((unsigned long)pg_vec
[i
], order
);
317 static void *alloc_one_pg_vec_page(unsigned long order
)
320 gfp_t gfp_flags
= GFP_KERNEL
| __GFP_COMP
| __GFP_ZERO
|
321 __GFP_NOWARN
| __GFP_NORETRY
;
323 buffer
= (void *)__get_free_pages(gfp_flags
, order
);
327 buffer
= vzalloc((1 << order
) * PAGE_SIZE
);
331 gfp_flags
&= ~__GFP_NORETRY
;
332 return (void *)__get_free_pages(gfp_flags
, order
);
335 static void **alloc_pg_vec(struct netlink_sock
*nlk
,
336 struct nl_mmap_req
*req
, unsigned int order
)
338 unsigned int block_nr
= req
->nm_block_nr
;
342 pg_vec
= kcalloc(block_nr
, sizeof(void *), GFP_KERNEL
);
346 for (i
= 0; i
< block_nr
; i
++) {
347 pg_vec
[i
] = alloc_one_pg_vec_page(order
);
348 if (pg_vec
[i
] == NULL
)
354 free_pg_vec(pg_vec
, order
, block_nr
);
358 static int netlink_set_ring(struct sock
*sk
, struct nl_mmap_req
*req
,
359 bool closing
, bool tx_ring
)
361 struct netlink_sock
*nlk
= nlk_sk(sk
);
362 struct netlink_ring
*ring
;
363 struct sk_buff_head
*queue
;
364 void **pg_vec
= NULL
;
365 unsigned int order
= 0;
368 ring
= tx_ring
? &nlk
->tx_ring
: &nlk
->rx_ring
;
369 queue
= tx_ring
? &sk
->sk_write_queue
: &sk
->sk_receive_queue
;
372 if (atomic_read(&nlk
->mapped
))
374 if (atomic_read(&ring
->pending
))
378 if (req
->nm_block_nr
) {
379 if (ring
->pg_vec
!= NULL
)
382 if ((int)req
->nm_block_size
<= 0)
384 if (!PAGE_ALIGNED(req
->nm_block_size
))
386 if (req
->nm_frame_size
< NL_MMAP_HDRLEN
)
388 if (!IS_ALIGNED(req
->nm_frame_size
, NL_MMAP_MSG_ALIGNMENT
))
391 ring
->frames_per_block
= req
->nm_block_size
/
393 if (ring
->frames_per_block
== 0)
395 if (ring
->frames_per_block
* req
->nm_block_nr
!=
399 order
= get_order(req
->nm_block_size
);
400 pg_vec
= alloc_pg_vec(nlk
, req
, order
);
404 if (req
->nm_frame_nr
)
409 mutex_lock(&nlk
->pg_vec_lock
);
410 if (closing
|| atomic_read(&nlk
->mapped
) == 0) {
412 spin_lock_bh(&queue
->lock
);
414 ring
->frame_max
= req
->nm_frame_nr
- 1;
416 ring
->frame_size
= req
->nm_frame_size
;
417 ring
->pg_vec_pages
= req
->nm_block_size
/ PAGE_SIZE
;
419 swap(ring
->pg_vec_len
, req
->nm_block_nr
);
420 swap(ring
->pg_vec_order
, order
);
421 swap(ring
->pg_vec
, pg_vec
);
423 __skb_queue_purge(queue
);
424 spin_unlock_bh(&queue
->lock
);
426 WARN_ON(atomic_read(&nlk
->mapped
));
428 mutex_unlock(&nlk
->pg_vec_lock
);
431 free_pg_vec(pg_vec
, order
, req
->nm_block_nr
);
435 static void netlink_mm_open(struct vm_area_struct
*vma
)
437 struct file
*file
= vma
->vm_file
;
438 struct socket
*sock
= file
->private_data
;
439 struct sock
*sk
= sock
->sk
;
442 atomic_inc(&nlk_sk(sk
)->mapped
);
445 static void netlink_mm_close(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_dec(&nlk_sk(sk
)->mapped
);
455 static const struct vm_operations_struct netlink_mmap_ops
= {
456 .open
= netlink_mm_open
,
457 .close
= netlink_mm_close
,
460 static int netlink_mmap(struct file
*file
, struct socket
*sock
,
461 struct vm_area_struct
*vma
)
463 struct sock
*sk
= sock
->sk
;
464 struct netlink_sock
*nlk
= nlk_sk(sk
);
465 struct netlink_ring
*ring
;
466 unsigned long start
, size
, expected
;
473 mutex_lock(&nlk
->pg_vec_lock
);
476 for (ring
= &nlk
->rx_ring
; ring
<= &nlk
->tx_ring
; ring
++) {
477 if (ring
->pg_vec
== NULL
)
479 expected
+= ring
->pg_vec_len
* ring
->pg_vec_pages
* PAGE_SIZE
;
485 size
= vma
->vm_end
- vma
->vm_start
;
486 if (size
!= expected
)
489 start
= vma
->vm_start
;
490 for (ring
= &nlk
->rx_ring
; ring
<= &nlk
->tx_ring
; ring
++) {
491 if (ring
->pg_vec
== NULL
)
494 for (i
= 0; i
< ring
->pg_vec_len
; i
++) {
496 void *kaddr
= ring
->pg_vec
[i
];
499 for (pg_num
= 0; pg_num
< ring
->pg_vec_pages
; pg_num
++) {
500 page
= pgvec_to_page(kaddr
);
501 err
= vm_insert_page(vma
, start
, page
);
510 atomic_inc(&nlk
->mapped
);
511 vma
->vm_ops
= &netlink_mmap_ops
;
514 mutex_unlock(&nlk
->pg_vec_lock
);
518 static void netlink_frame_flush_dcache(const struct nl_mmap_hdr
*hdr
, unsigned int nm_len
)
520 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
521 struct page
*p_start
, *p_end
;
523 /* First page is flushed through netlink_{get,set}_status */
524 p_start
= pgvec_to_page(hdr
+ PAGE_SIZE
);
525 p_end
= pgvec_to_page((void *)hdr
+ NL_MMAP_HDRLEN
+ nm_len
- 1);
526 while (p_start
<= p_end
) {
527 flush_dcache_page(p_start
);
533 static enum nl_mmap_status
netlink_get_status(const struct nl_mmap_hdr
*hdr
)
536 flush_dcache_page(pgvec_to_page(hdr
));
537 return hdr
->nm_status
;
540 static void netlink_set_status(struct nl_mmap_hdr
*hdr
,
541 enum nl_mmap_status status
)
544 hdr
->nm_status
= status
;
545 flush_dcache_page(pgvec_to_page(hdr
));
548 static struct nl_mmap_hdr
*
549 __netlink_lookup_frame(const struct netlink_ring
*ring
, unsigned int pos
)
551 unsigned int pg_vec_pos
, frame_off
;
553 pg_vec_pos
= pos
/ ring
->frames_per_block
;
554 frame_off
= pos
% ring
->frames_per_block
;
556 return ring
->pg_vec
[pg_vec_pos
] + (frame_off
* ring
->frame_size
);
559 static struct nl_mmap_hdr
*
560 netlink_lookup_frame(const struct netlink_ring
*ring
, unsigned int pos
,
561 enum nl_mmap_status status
)
563 struct nl_mmap_hdr
*hdr
;
565 hdr
= __netlink_lookup_frame(ring
, pos
);
566 if (netlink_get_status(hdr
) != status
)
572 static struct nl_mmap_hdr
*
573 netlink_current_frame(const struct netlink_ring
*ring
,
574 enum nl_mmap_status status
)
576 return netlink_lookup_frame(ring
, ring
->head
, status
);
579 static struct nl_mmap_hdr
*
580 netlink_previous_frame(const struct netlink_ring
*ring
,
581 enum nl_mmap_status status
)
585 prev
= ring
->head
? ring
->head
- 1 : ring
->frame_max
;
586 return netlink_lookup_frame(ring
, prev
, status
);
589 static void netlink_increment_head(struct netlink_ring
*ring
)
591 ring
->head
= ring
->head
!= ring
->frame_max
? ring
->head
+ 1 : 0;
594 static void netlink_forward_ring(struct netlink_ring
*ring
)
596 unsigned int head
= ring
->head
, pos
= head
;
597 const struct nl_mmap_hdr
*hdr
;
600 hdr
= __netlink_lookup_frame(ring
, pos
);
601 if (hdr
->nm_status
== NL_MMAP_STATUS_UNUSED
)
603 if (hdr
->nm_status
!= NL_MMAP_STATUS_SKIP
)
605 netlink_increment_head(ring
);
606 } while (ring
->head
!= head
);
609 static bool netlink_dump_space(struct netlink_sock
*nlk
)
611 struct netlink_ring
*ring
= &nlk
->rx_ring
;
612 struct nl_mmap_hdr
*hdr
;
615 hdr
= netlink_current_frame(ring
, NL_MMAP_STATUS_UNUSED
);
619 n
= ring
->head
+ ring
->frame_max
/ 2;
620 if (n
> ring
->frame_max
)
621 n
-= ring
->frame_max
;
623 hdr
= __netlink_lookup_frame(ring
, n
);
625 return hdr
->nm_status
== NL_MMAP_STATUS_UNUSED
;
628 static unsigned int netlink_poll(struct file
*file
, struct socket
*sock
,
631 struct sock
*sk
= sock
->sk
;
632 struct netlink_sock
*nlk
= nlk_sk(sk
);
636 if (nlk
->rx_ring
.pg_vec
!= NULL
) {
637 /* Memory mapped sockets don't call recvmsg(), so flow control
638 * for dumps is performed here. A dump is allowed to continue
639 * if at least half the ring is unused.
641 while (nlk
->cb_running
&& netlink_dump_space(nlk
)) {
642 err
= netlink_dump(sk
);
645 sk
->sk_error_report(sk
);
649 netlink_rcv_wake(sk
);
652 mask
= datagram_poll(file
, sock
, wait
);
654 spin_lock_bh(&sk
->sk_receive_queue
.lock
);
655 if (nlk
->rx_ring
.pg_vec
) {
656 netlink_forward_ring(&nlk
->rx_ring
);
657 if (!netlink_previous_frame(&nlk
->rx_ring
, NL_MMAP_STATUS_UNUSED
))
658 mask
|= POLLIN
| POLLRDNORM
;
660 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
662 spin_lock_bh(&sk
->sk_write_queue
.lock
);
663 if (nlk
->tx_ring
.pg_vec
) {
664 if (netlink_current_frame(&nlk
->tx_ring
, NL_MMAP_STATUS_UNUSED
))
665 mask
|= POLLOUT
| POLLWRNORM
;
667 spin_unlock_bh(&sk
->sk_write_queue
.lock
);
672 static struct nl_mmap_hdr
*netlink_mmap_hdr(struct sk_buff
*skb
)
674 return (struct nl_mmap_hdr
*)(skb
->head
- NL_MMAP_HDRLEN
);
677 static void netlink_ring_setup_skb(struct sk_buff
*skb
, struct sock
*sk
,
678 struct netlink_ring
*ring
,
679 struct nl_mmap_hdr
*hdr
)
684 size
= ring
->frame_size
- NL_MMAP_HDRLEN
;
685 data
= (void *)hdr
+ NL_MMAP_HDRLEN
;
689 skb_reset_tail_pointer(skb
);
690 skb
->end
= skb
->tail
+ size
;
693 skb
->destructor
= netlink_skb_destructor
;
694 NETLINK_CB(skb
).flags
|= NETLINK_SKB_MMAPED
;
695 NETLINK_CB(skb
).sk
= sk
;
698 static int netlink_mmap_sendmsg(struct sock
*sk
, struct msghdr
*msg
,
699 u32 dst_portid
, u32 dst_group
,
700 struct scm_cookie
*scm
)
702 struct netlink_sock
*nlk
= nlk_sk(sk
);
703 struct netlink_ring
*ring
;
704 struct nl_mmap_hdr
*hdr
;
707 int err
= 0, len
= 0;
709 mutex_lock(&nlk
->pg_vec_lock
);
711 ring
= &nlk
->tx_ring
;
712 maxlen
= ring
->frame_size
- NL_MMAP_HDRLEN
;
717 hdr
= netlink_current_frame(ring
, NL_MMAP_STATUS_VALID
);
719 if (!(msg
->msg_flags
& MSG_DONTWAIT
) &&
720 atomic_read(&nlk
->tx_ring
.pending
))
725 nm_len
= ACCESS_ONCE(hdr
->nm_len
);
726 if (nm_len
> maxlen
) {
731 netlink_frame_flush_dcache(hdr
, nm_len
);
733 skb
= alloc_skb(nm_len
, GFP_KERNEL
);
738 __skb_put(skb
, nm_len
);
739 memcpy(skb
->data
, (void *)hdr
+ NL_MMAP_HDRLEN
, nm_len
);
740 netlink_set_status(hdr
, NL_MMAP_STATUS_UNUSED
);
742 netlink_increment_head(ring
);
744 NETLINK_CB(skb
).portid
= nlk
->portid
;
745 NETLINK_CB(skb
).dst_group
= dst_group
;
746 NETLINK_CB(skb
).creds
= scm
->creds
;
748 err
= security_netlink_send(sk
, skb
);
754 if (unlikely(dst_group
)) {
755 atomic_inc(&skb
->users
);
756 netlink_broadcast(sk
, skb
, dst_portid
, dst_group
,
759 err
= netlink_unicast(sk
, skb
, dst_portid
,
760 msg
->msg_flags
& MSG_DONTWAIT
);
765 } while (hdr
!= NULL
||
766 (!(msg
->msg_flags
& MSG_DONTWAIT
) &&
767 atomic_read(&nlk
->tx_ring
.pending
)));
772 mutex_unlock(&nlk
->pg_vec_lock
);
776 static void netlink_queue_mmaped_skb(struct sock
*sk
, struct sk_buff
*skb
)
778 struct nl_mmap_hdr
*hdr
;
780 hdr
= netlink_mmap_hdr(skb
);
781 hdr
->nm_len
= skb
->len
;
782 hdr
->nm_group
= NETLINK_CB(skb
).dst_group
;
783 hdr
->nm_pid
= NETLINK_CB(skb
).creds
.pid
;
784 hdr
->nm_uid
= from_kuid(sk_user_ns(sk
), NETLINK_CB(skb
).creds
.uid
);
785 hdr
->nm_gid
= from_kgid(sk_user_ns(sk
), NETLINK_CB(skb
).creds
.gid
);
786 netlink_frame_flush_dcache(hdr
, hdr
->nm_len
);
787 netlink_set_status(hdr
, NL_MMAP_STATUS_VALID
);
789 NETLINK_CB(skb
).flags
|= NETLINK_SKB_DELIVERED
;
793 static void netlink_ring_set_copied(struct sock
*sk
, struct sk_buff
*skb
)
795 struct netlink_sock
*nlk
= nlk_sk(sk
);
796 struct netlink_ring
*ring
= &nlk
->rx_ring
;
797 struct nl_mmap_hdr
*hdr
;
799 spin_lock_bh(&sk
->sk_receive_queue
.lock
);
800 hdr
= netlink_current_frame(ring
, NL_MMAP_STATUS_UNUSED
);
802 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
807 netlink_increment_head(ring
);
808 __skb_queue_tail(&sk
->sk_receive_queue
, skb
);
809 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
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_set_status(hdr
, NL_MMAP_STATUS_COPY
);
819 #else /* CONFIG_NETLINK_MMAP */
820 #define netlink_skb_is_mmaped(skb) false
821 #define netlink_rx_is_mmaped(sk) false
822 #define netlink_tx_is_mmaped(sk) false
823 #define netlink_mmap sock_no_mmap
824 #define netlink_poll datagram_poll
825 #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, scm) 0
826 #endif /* CONFIG_NETLINK_MMAP */
828 static void netlink_skb_destructor(struct sk_buff
*skb
)
830 #ifdef CONFIG_NETLINK_MMAP
831 struct nl_mmap_hdr
*hdr
;
832 struct netlink_ring
*ring
;
835 /* If a packet from the kernel to userspace was freed because of an
836 * error without being delivered to userspace, the kernel must reset
837 * the status. In the direction userspace to kernel, the status is
838 * always reset here after the packet was processed and freed.
840 if (netlink_skb_is_mmaped(skb
)) {
841 hdr
= netlink_mmap_hdr(skb
);
842 sk
= NETLINK_CB(skb
).sk
;
844 if (NETLINK_CB(skb
).flags
& NETLINK_SKB_TX
) {
845 netlink_set_status(hdr
, NL_MMAP_STATUS_UNUSED
);
846 ring
= &nlk_sk(sk
)->tx_ring
;
848 if (!(NETLINK_CB(skb
).flags
& NETLINK_SKB_DELIVERED
)) {
850 netlink_set_status(hdr
, NL_MMAP_STATUS_VALID
);
852 ring
= &nlk_sk(sk
)->rx_ring
;
855 WARN_ON(atomic_read(&ring
->pending
) == 0);
856 atomic_dec(&ring
->pending
);
862 if (is_vmalloc_addr(skb
->head
)) {
864 !atomic_dec_return(&(skb_shinfo(skb
)->dataref
)))
873 static void netlink_skb_set_owner_r(struct sk_buff
*skb
, struct sock
*sk
)
875 WARN_ON(skb
->sk
!= NULL
);
877 skb
->destructor
= netlink_skb_destructor
;
878 atomic_add(skb
->truesize
, &sk
->sk_rmem_alloc
);
879 sk_mem_charge(sk
, skb
->truesize
);
882 static void netlink_sock_destruct(struct sock
*sk
)
884 struct netlink_sock
*nlk
= nlk_sk(sk
);
886 if (nlk
->cb_running
) {
888 nlk
->cb
.done(&nlk
->cb
);
890 module_put(nlk
->cb
.module
);
891 kfree_skb(nlk
->cb
.skb
);
894 skb_queue_purge(&sk
->sk_receive_queue
);
895 #ifdef CONFIG_NETLINK_MMAP
897 struct nl_mmap_req req
;
899 memset(&req
, 0, sizeof(req
));
900 if (nlk
->rx_ring
.pg_vec
)
901 netlink_set_ring(sk
, &req
, true, false);
902 memset(&req
, 0, sizeof(req
));
903 if (nlk
->tx_ring
.pg_vec
)
904 netlink_set_ring(sk
, &req
, true, true);
906 #endif /* CONFIG_NETLINK_MMAP */
908 if (!sock_flag(sk
, SOCK_DEAD
)) {
909 printk(KERN_ERR
"Freeing alive netlink socket %p\n", sk
);
913 WARN_ON(atomic_read(&sk
->sk_rmem_alloc
));
914 WARN_ON(atomic_read(&sk
->sk_wmem_alloc
));
915 WARN_ON(nlk_sk(sk
)->groups
);
918 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
919 * SMP. Look, when several writers sleep and reader wakes them up, all but one
920 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
921 * this, _but_ remember, it adds useless work on UP machines.
924 void netlink_table_grab(void)
925 __acquires(nl_table_lock
)
929 write_lock_irq(&nl_table_lock
);
931 if (atomic_read(&nl_table_users
)) {
932 DECLARE_WAITQUEUE(wait
, current
);
934 add_wait_queue_exclusive(&nl_table_wait
, &wait
);
936 set_current_state(TASK_UNINTERRUPTIBLE
);
937 if (atomic_read(&nl_table_users
) == 0)
939 write_unlock_irq(&nl_table_lock
);
941 write_lock_irq(&nl_table_lock
);
944 __set_current_state(TASK_RUNNING
);
945 remove_wait_queue(&nl_table_wait
, &wait
);
949 void netlink_table_ungrab(void)
950 __releases(nl_table_lock
)
952 write_unlock_irq(&nl_table_lock
);
953 wake_up(&nl_table_wait
);
957 netlink_lock_table(void)
959 /* read_lock() synchronizes us to netlink_table_grab */
961 read_lock(&nl_table_lock
);
962 atomic_inc(&nl_table_users
);
963 read_unlock(&nl_table_lock
);
967 netlink_unlock_table(void)
969 if (atomic_dec_and_test(&nl_table_users
))
970 wake_up(&nl_table_wait
);
973 struct netlink_compare_arg
979 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
980 #define netlink_compare_arg_len \
981 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
983 static inline int netlink_compare(struct rhashtable_compare_arg
*arg
,
986 const struct netlink_compare_arg
*x
= arg
->key
;
987 const struct netlink_sock
*nlk
= ptr
;
989 return nlk
->portid
!= x
->portid
||
990 !net_eq(sock_net(&nlk
->sk
), read_pnet(&x
->pnet
));
993 static void netlink_compare_arg_init(struct netlink_compare_arg
*arg
,
994 struct net
*net
, u32 portid
)
996 memset(arg
, 0, sizeof(*arg
));
997 write_pnet(&arg
->pnet
, net
);
998 arg
->portid
= portid
;
1001 static struct sock
*__netlink_lookup(struct netlink_table
*table
, u32 portid
,
1004 struct netlink_compare_arg arg
;
1006 netlink_compare_arg_init(&arg
, net
, portid
);
1007 return rhashtable_lookup_fast(&table
->hash
, &arg
,
1008 netlink_rhashtable_params
);
1011 static int __netlink_insert(struct netlink_table
*table
, struct sock
*sk
)
1013 struct netlink_compare_arg arg
;
1015 netlink_compare_arg_init(&arg
, sock_net(sk
), nlk_sk(sk
)->portid
);
1016 return rhashtable_lookup_insert_key(&table
->hash
, &arg
,
1018 netlink_rhashtable_params
);
1021 static struct sock
*netlink_lookup(struct net
*net
, int protocol
, u32 portid
)
1023 struct netlink_table
*table
= &nl_table
[protocol
];
1027 sk
= __netlink_lookup(table
, portid
, net
);
1035 static const struct proto_ops netlink_ops
;
1038 netlink_update_listeners(struct sock
*sk
)
1040 struct netlink_table
*tbl
= &nl_table
[sk
->sk_protocol
];
1043 struct listeners
*listeners
;
1045 listeners
= nl_deref_protected(tbl
->listeners
);
1049 for (i
= 0; i
< NLGRPLONGS(tbl
->groups
); i
++) {
1051 sk_for_each_bound(sk
, &tbl
->mc_list
) {
1052 if (i
< NLGRPLONGS(nlk_sk(sk
)->ngroups
))
1053 mask
|= nlk_sk(sk
)->groups
[i
];
1055 listeners
->masks
[i
] = mask
;
1057 /* this function is only called with the netlink table "grabbed", which
1058 * makes sure updates are visible before bind or setsockopt return. */
1061 static int netlink_insert(struct sock
*sk
, u32 portid
)
1063 struct netlink_table
*table
= &nl_table
[sk
->sk_protocol
];
1069 if (nlk_sk(sk
)->portid
)
1073 if (BITS_PER_LONG
> 32 &&
1074 unlikely(atomic_read(&table
->hash
.nelems
) >= UINT_MAX
))
1077 nlk_sk(sk
)->portid
= portid
;
1080 err
= __netlink_insert(table
, sk
);
1092 static void netlink_remove(struct sock
*sk
)
1094 struct netlink_table
*table
;
1096 table
= &nl_table
[sk
->sk_protocol
];
1097 if (!rhashtable_remove_fast(&table
->hash
, &nlk_sk(sk
)->node
,
1098 netlink_rhashtable_params
)) {
1099 WARN_ON(atomic_read(&sk
->sk_refcnt
) == 1);
1103 netlink_table_grab();
1104 if (nlk_sk(sk
)->subscriptions
) {
1105 __sk_del_bind_node(sk
);
1106 netlink_update_listeners(sk
);
1108 if (sk
->sk_protocol
== NETLINK_GENERIC
)
1109 atomic_inc(&genl_sk_destructing_cnt
);
1110 netlink_table_ungrab();
1113 static struct proto netlink_proto
= {
1115 .owner
= THIS_MODULE
,
1116 .obj_size
= sizeof(struct netlink_sock
),
1119 static int __netlink_create(struct net
*net
, struct socket
*sock
,
1120 struct mutex
*cb_mutex
, int protocol
)
1123 struct netlink_sock
*nlk
;
1125 sock
->ops
= &netlink_ops
;
1127 sk
= sk_alloc(net
, PF_NETLINK
, GFP_KERNEL
, &netlink_proto
);
1131 sock_init_data(sock
, sk
);
1135 nlk
->cb_mutex
= cb_mutex
;
1137 nlk
->cb_mutex
= &nlk
->cb_def_mutex
;
1138 mutex_init(nlk
->cb_mutex
);
1140 init_waitqueue_head(&nlk
->wait
);
1141 #ifdef CONFIG_NETLINK_MMAP
1142 mutex_init(&nlk
->pg_vec_lock
);
1145 sk
->sk_destruct
= netlink_sock_destruct
;
1146 sk
->sk_protocol
= protocol
;
1150 static int netlink_create(struct net
*net
, struct socket
*sock
, int protocol
,
1153 struct module
*module
= NULL
;
1154 struct mutex
*cb_mutex
;
1155 struct netlink_sock
*nlk
;
1156 int (*bind
)(struct net
*net
, int group
);
1157 void (*unbind
)(struct net
*net
, int group
);
1160 sock
->state
= SS_UNCONNECTED
;
1162 if (sock
->type
!= SOCK_RAW
&& sock
->type
!= SOCK_DGRAM
)
1163 return -ESOCKTNOSUPPORT
;
1165 if (protocol
< 0 || protocol
>= MAX_LINKS
)
1166 return -EPROTONOSUPPORT
;
1168 netlink_lock_table();
1169 #ifdef CONFIG_MODULES
1170 if (!nl_table
[protocol
].registered
) {
1171 netlink_unlock_table();
1172 request_module("net-pf-%d-proto-%d", PF_NETLINK
, protocol
);
1173 netlink_lock_table();
1176 if (nl_table
[protocol
].registered
&&
1177 try_module_get(nl_table
[protocol
].module
))
1178 module
= nl_table
[protocol
].module
;
1180 err
= -EPROTONOSUPPORT
;
1181 cb_mutex
= nl_table
[protocol
].cb_mutex
;
1182 bind
= nl_table
[protocol
].bind
;
1183 unbind
= nl_table
[protocol
].unbind
;
1184 netlink_unlock_table();
1189 err
= __netlink_create(net
, sock
, cb_mutex
, protocol
);
1194 sock_prot_inuse_add(net
, &netlink_proto
, 1);
1197 nlk
= nlk_sk(sock
->sk
);
1198 nlk
->module
= module
;
1199 nlk
->netlink_bind
= bind
;
1200 nlk
->netlink_unbind
= unbind
;
1209 static void deferred_put_nlk_sk(struct rcu_head
*head
)
1211 struct netlink_sock
*nlk
= container_of(head
, struct netlink_sock
, rcu
);
1216 static int netlink_release(struct socket
*sock
)
1218 struct sock
*sk
= sock
->sk
;
1219 struct netlink_sock
*nlk
;
1229 * OK. Socket is unlinked, any packets that arrive now
1233 /* must not acquire netlink_table_lock in any way again before unbind
1234 * and notifying genetlink is done as otherwise it might deadlock
1236 if (nlk
->netlink_unbind
) {
1239 for (i
= 0; i
< nlk
->ngroups
; i
++)
1240 if (test_bit(i
, nlk
->groups
))
1241 nlk
->netlink_unbind(sock_net(sk
), i
+ 1);
1243 if (sk
->sk_protocol
== NETLINK_GENERIC
&&
1244 atomic_dec_return(&genl_sk_destructing_cnt
) == 0)
1245 wake_up(&genl_sk_destructing_waitq
);
1248 wake_up_interruptible_all(&nlk
->wait
);
1250 skb_queue_purge(&sk
->sk_write_queue
);
1253 struct netlink_notify n
= {
1254 .net
= sock_net(sk
),
1255 .protocol
= sk
->sk_protocol
,
1256 .portid
= nlk
->portid
,
1258 atomic_notifier_call_chain(&netlink_chain
,
1259 NETLINK_URELEASE
, &n
);
1262 module_put(nlk
->module
);
1264 if (netlink_is_kernel(sk
)) {
1265 netlink_table_grab();
1266 BUG_ON(nl_table
[sk
->sk_protocol
].registered
== 0);
1267 if (--nl_table
[sk
->sk_protocol
].registered
== 0) {
1268 struct listeners
*old
;
1270 old
= nl_deref_protected(nl_table
[sk
->sk_protocol
].listeners
);
1271 RCU_INIT_POINTER(nl_table
[sk
->sk_protocol
].listeners
, NULL
);
1272 kfree_rcu(old
, rcu
);
1273 nl_table
[sk
->sk_protocol
].module
= NULL
;
1274 nl_table
[sk
->sk_protocol
].bind
= NULL
;
1275 nl_table
[sk
->sk_protocol
].unbind
= NULL
;
1276 nl_table
[sk
->sk_protocol
].flags
= 0;
1277 nl_table
[sk
->sk_protocol
].registered
= 0;
1279 netlink_table_ungrab();
1286 sock_prot_inuse_add(sock_net(sk
), &netlink_proto
, -1);
1288 call_rcu(&nlk
->rcu
, deferred_put_nlk_sk
);
1292 static int netlink_autobind(struct socket
*sock
)
1294 struct sock
*sk
= sock
->sk
;
1295 struct net
*net
= sock_net(sk
);
1296 struct netlink_table
*table
= &nl_table
[sk
->sk_protocol
];
1297 s32 portid
= task_tgid_vnr(current
);
1299 static s32 rover
= -4097;
1304 if (__netlink_lookup(table
, portid
, net
)) {
1305 /* Bind collision, search negative portid values. */
1314 err
= netlink_insert(sk
, portid
);
1315 if (err
== -EADDRINUSE
)
1318 /* If 2 threads race to autobind, that is fine. */
1326 * __netlink_ns_capable - General netlink message capability test
1327 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
1328 * @user_ns: The user namespace of the capability to use
1329 * @cap: The capability to use
1331 * Test to see if the opener of the socket we received the message
1332 * from had when the netlink socket was created and the sender of the
1333 * message has has the capability @cap in the user namespace @user_ns.
1335 bool __netlink_ns_capable(const struct netlink_skb_parms
*nsp
,
1336 struct user_namespace
*user_ns
, int cap
)
1338 return ((nsp
->flags
& NETLINK_SKB_DST
) ||
1339 file_ns_capable(nsp
->sk
->sk_socket
->file
, user_ns
, cap
)) &&
1340 ns_capable(user_ns
, cap
);
1342 EXPORT_SYMBOL(__netlink_ns_capable
);
1345 * netlink_ns_capable - General netlink message capability test
1346 * @skb: socket buffer holding a netlink command from userspace
1347 * @user_ns: The user namespace of the capability to use
1348 * @cap: The capability to use
1350 * Test to see if the opener of the socket we received the message
1351 * from had when the netlink socket was created and the sender of the
1352 * message has has the capability @cap in the user namespace @user_ns.
1354 bool netlink_ns_capable(const struct sk_buff
*skb
,
1355 struct user_namespace
*user_ns
, int cap
)
1357 return __netlink_ns_capable(&NETLINK_CB(skb
), user_ns
, cap
);
1359 EXPORT_SYMBOL(netlink_ns_capable
);
1362 * netlink_capable - Netlink global message capability test
1363 * @skb: socket buffer holding a netlink command from userspace
1364 * @cap: The capability to use
1366 * Test to see if the opener of the socket we received the message
1367 * from had when the netlink socket was created and the sender of the
1368 * message has has the capability @cap in all user namespaces.
1370 bool netlink_capable(const struct sk_buff
*skb
, int cap
)
1372 return netlink_ns_capable(skb
, &init_user_ns
, cap
);
1374 EXPORT_SYMBOL(netlink_capable
);
1377 * netlink_net_capable - Netlink network namespace message capability test
1378 * @skb: socket buffer holding a netlink command from userspace
1379 * @cap: The capability to use
1381 * Test to see if the opener of the socket we received the message
1382 * from had when the netlink socket was created and the sender of the
1383 * message has has the capability @cap over the network namespace of
1384 * the socket we received the message from.
1386 bool netlink_net_capable(const struct sk_buff
*skb
, int cap
)
1388 return netlink_ns_capable(skb
, sock_net(skb
->sk
)->user_ns
, cap
);
1390 EXPORT_SYMBOL(netlink_net_capable
);
1392 static inline int netlink_allowed(const struct socket
*sock
, unsigned int flag
)
1394 return (nl_table
[sock
->sk
->sk_protocol
].flags
& flag
) ||
1395 ns_capable(sock_net(sock
->sk
)->user_ns
, CAP_NET_ADMIN
);
1399 netlink_update_subscriptions(struct sock
*sk
, unsigned int subscriptions
)
1401 struct netlink_sock
*nlk
= nlk_sk(sk
);
1403 if (nlk
->subscriptions
&& !subscriptions
)
1404 __sk_del_bind_node(sk
);
1405 else if (!nlk
->subscriptions
&& subscriptions
)
1406 sk_add_bind_node(sk
, &nl_table
[sk
->sk_protocol
].mc_list
);
1407 nlk
->subscriptions
= subscriptions
;
1410 static int netlink_realloc_groups(struct sock
*sk
)
1412 struct netlink_sock
*nlk
= nlk_sk(sk
);
1413 unsigned int groups
;
1414 unsigned long *new_groups
;
1417 netlink_table_grab();
1419 groups
= nl_table
[sk
->sk_protocol
].groups
;
1420 if (!nl_table
[sk
->sk_protocol
].registered
) {
1425 if (nlk
->ngroups
>= groups
)
1428 new_groups
= krealloc(nlk
->groups
, NLGRPSZ(groups
), GFP_ATOMIC
);
1429 if (new_groups
== NULL
) {
1433 memset((char *)new_groups
+ NLGRPSZ(nlk
->ngroups
), 0,
1434 NLGRPSZ(groups
) - NLGRPSZ(nlk
->ngroups
));
1436 nlk
->groups
= new_groups
;
1437 nlk
->ngroups
= groups
;
1439 netlink_table_ungrab();
1443 static void netlink_undo_bind(int group
, long unsigned int groups
,
1446 struct netlink_sock
*nlk
= nlk_sk(sk
);
1449 if (!nlk
->netlink_unbind
)
1452 for (undo
= 0; undo
< group
; undo
++)
1453 if (test_bit(undo
, &groups
))
1454 nlk
->netlink_unbind(sock_net(sk
), undo
+ 1);
1457 static int netlink_bind(struct socket
*sock
, struct sockaddr
*addr
,
1460 struct sock
*sk
= sock
->sk
;
1461 struct net
*net
= sock_net(sk
);
1462 struct netlink_sock
*nlk
= nlk_sk(sk
);
1463 struct sockaddr_nl
*nladdr
= (struct sockaddr_nl
*)addr
;
1465 long unsigned int groups
= nladdr
->nl_groups
;
1467 if (addr_len
< sizeof(struct sockaddr_nl
))
1470 if (nladdr
->nl_family
!= AF_NETLINK
)
1473 /* Only superuser is allowed to listen multicasts */
1475 if (!netlink_allowed(sock
, NL_CFG_F_NONROOT_RECV
))
1477 err
= netlink_realloc_groups(sk
);
1483 if (nladdr
->nl_pid
!= nlk
->portid
)
1486 if (nlk
->netlink_bind
&& groups
) {
1489 for (group
= 0; group
< nlk
->ngroups
; group
++) {
1490 if (!test_bit(group
, &groups
))
1492 err
= nlk
->netlink_bind(net
, group
+ 1);
1495 netlink_undo_bind(group
, groups
, sk
);
1501 err
= nladdr
->nl_pid
?
1502 netlink_insert(sk
, nladdr
->nl_pid
) :
1503 netlink_autobind(sock
);
1505 netlink_undo_bind(nlk
->ngroups
, groups
, sk
);
1510 if (!groups
&& (nlk
->groups
== NULL
|| !(u32
)nlk
->groups
[0]))
1513 netlink_table_grab();
1514 netlink_update_subscriptions(sk
, nlk
->subscriptions
+
1516 hweight32(nlk
->groups
[0]));
1517 nlk
->groups
[0] = (nlk
->groups
[0] & ~0xffffffffUL
) | groups
;
1518 netlink_update_listeners(sk
);
1519 netlink_table_ungrab();
1524 static int netlink_connect(struct socket
*sock
, struct sockaddr
*addr
,
1525 int alen
, int flags
)
1528 struct sock
*sk
= sock
->sk
;
1529 struct netlink_sock
*nlk
= nlk_sk(sk
);
1530 struct sockaddr_nl
*nladdr
= (struct sockaddr_nl
*)addr
;
1532 if (alen
< sizeof(addr
->sa_family
))
1535 if (addr
->sa_family
== AF_UNSPEC
) {
1536 sk
->sk_state
= NETLINK_UNCONNECTED
;
1537 nlk
->dst_portid
= 0;
1541 if (addr
->sa_family
!= AF_NETLINK
)
1544 if ((nladdr
->nl_groups
|| nladdr
->nl_pid
) &&
1545 !netlink_allowed(sock
, NL_CFG_F_NONROOT_SEND
))
1549 err
= netlink_autobind(sock
);
1552 sk
->sk_state
= NETLINK_CONNECTED
;
1553 nlk
->dst_portid
= nladdr
->nl_pid
;
1554 nlk
->dst_group
= ffs(nladdr
->nl_groups
);
1560 static int netlink_getname(struct socket
*sock
, struct sockaddr
*addr
,
1561 int *addr_len
, int peer
)
1563 struct sock
*sk
= sock
->sk
;
1564 struct netlink_sock
*nlk
= nlk_sk(sk
);
1565 DECLARE_SOCKADDR(struct sockaddr_nl
*, nladdr
, addr
);
1567 nladdr
->nl_family
= AF_NETLINK
;
1569 *addr_len
= sizeof(*nladdr
);
1572 nladdr
->nl_pid
= nlk
->dst_portid
;
1573 nladdr
->nl_groups
= netlink_group_mask(nlk
->dst_group
);
1575 nladdr
->nl_pid
= nlk
->portid
;
1576 nladdr
->nl_groups
= nlk
->groups
? nlk
->groups
[0] : 0;
1581 static struct sock
*netlink_getsockbyportid(struct sock
*ssk
, u32 portid
)
1584 struct netlink_sock
*nlk
;
1586 sock
= netlink_lookup(sock_net(ssk
), ssk
->sk_protocol
, portid
);
1588 return ERR_PTR(-ECONNREFUSED
);
1590 /* Don't bother queuing skb if kernel socket has no input function */
1592 if (sock
->sk_state
== NETLINK_CONNECTED
&&
1593 nlk
->dst_portid
!= nlk_sk(ssk
)->portid
) {
1595 return ERR_PTR(-ECONNREFUSED
);
1600 struct sock
*netlink_getsockbyfilp(struct file
*filp
)
1602 struct inode
*inode
= file_inode(filp
);
1605 if (!S_ISSOCK(inode
->i_mode
))
1606 return ERR_PTR(-ENOTSOCK
);
1608 sock
= SOCKET_I(inode
)->sk
;
1609 if (sock
->sk_family
!= AF_NETLINK
)
1610 return ERR_PTR(-EINVAL
);
1616 static struct sk_buff
*netlink_alloc_large_skb(unsigned int size
,
1619 struct sk_buff
*skb
;
1622 if (size
<= NLMSG_GOODSIZE
|| broadcast
)
1623 return alloc_skb(size
, GFP_KERNEL
);
1625 size
= SKB_DATA_ALIGN(size
) +
1626 SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
1628 data
= vmalloc(size
);
1632 skb
= __build_skb(data
, size
);
1636 skb
->destructor
= netlink_skb_destructor
;
1642 * Attach a skb to a netlink socket.
1643 * The caller must hold a reference to the destination socket. On error, the
1644 * reference is dropped. The skb is not send to the destination, just all
1645 * all error checks are performed and memory in the queue is reserved.
1647 * < 0: error. skb freed, reference to sock dropped.
1649 * 1: repeat lookup - reference dropped while waiting for socket memory.
1651 int netlink_attachskb(struct sock
*sk
, struct sk_buff
*skb
,
1652 long *timeo
, struct sock
*ssk
)
1654 struct netlink_sock
*nlk
;
1658 if ((atomic_read(&sk
->sk_rmem_alloc
) > sk
->sk_rcvbuf
||
1659 test_bit(NETLINK_CONGESTED
, &nlk
->state
)) &&
1660 !netlink_skb_is_mmaped(skb
)) {
1661 DECLARE_WAITQUEUE(wait
, current
);
1663 if (!ssk
|| netlink_is_kernel(ssk
))
1664 netlink_overrun(sk
);
1670 __set_current_state(TASK_INTERRUPTIBLE
);
1671 add_wait_queue(&nlk
->wait
, &wait
);
1673 if ((atomic_read(&sk
->sk_rmem_alloc
) > sk
->sk_rcvbuf
||
1674 test_bit(NETLINK_CONGESTED
, &nlk
->state
)) &&
1675 !sock_flag(sk
, SOCK_DEAD
))
1676 *timeo
= schedule_timeout(*timeo
);
1678 __set_current_state(TASK_RUNNING
);
1679 remove_wait_queue(&nlk
->wait
, &wait
);
1682 if (signal_pending(current
)) {
1684 return sock_intr_errno(*timeo
);
1688 netlink_skb_set_owner_r(skb
, sk
);
1692 static int __netlink_sendskb(struct sock
*sk
, struct sk_buff
*skb
)
1696 netlink_deliver_tap(skb
);
1698 #ifdef CONFIG_NETLINK_MMAP
1699 if (netlink_skb_is_mmaped(skb
))
1700 netlink_queue_mmaped_skb(sk
, skb
);
1701 else if (netlink_rx_is_mmaped(sk
))
1702 netlink_ring_set_copied(sk
, skb
);
1704 #endif /* CONFIG_NETLINK_MMAP */
1705 skb_queue_tail(&sk
->sk_receive_queue
, skb
);
1706 sk
->sk_data_ready(sk
);
1710 int netlink_sendskb(struct sock
*sk
, struct sk_buff
*skb
)
1712 int len
= __netlink_sendskb(sk
, skb
);
1718 void netlink_detachskb(struct sock
*sk
, struct sk_buff
*skb
)
1724 static struct sk_buff
*netlink_trim(struct sk_buff
*skb
, gfp_t allocation
)
1728 WARN_ON(skb
->sk
!= NULL
);
1729 if (netlink_skb_is_mmaped(skb
))
1732 delta
= skb
->end
- skb
->tail
;
1733 if (is_vmalloc_addr(skb
->head
) || delta
* 2 < skb
->truesize
)
1736 if (skb_shared(skb
)) {
1737 struct sk_buff
*nskb
= skb_clone(skb
, allocation
);
1744 if (!pskb_expand_head(skb
, 0, -delta
, allocation
))
1745 skb
->truesize
-= delta
;
1750 static int netlink_unicast_kernel(struct sock
*sk
, struct sk_buff
*skb
,
1754 struct netlink_sock
*nlk
= nlk_sk(sk
);
1756 ret
= -ECONNREFUSED
;
1757 if (nlk
->netlink_rcv
!= NULL
) {
1759 netlink_skb_set_owner_r(skb
, sk
);
1760 NETLINK_CB(skb
).sk
= ssk
;
1761 netlink_deliver_tap_kernel(sk
, ssk
, skb
);
1762 nlk
->netlink_rcv(skb
);
1771 int netlink_unicast(struct sock
*ssk
, struct sk_buff
*skb
,
1772 u32 portid
, int nonblock
)
1778 skb
= netlink_trim(skb
, gfp_any());
1780 timeo
= sock_sndtimeo(ssk
, nonblock
);
1782 sk
= netlink_getsockbyportid(ssk
, portid
);
1787 if (netlink_is_kernel(sk
))
1788 return netlink_unicast_kernel(sk
, skb
, ssk
);
1790 if (sk_filter(sk
, skb
)) {
1797 err
= netlink_attachskb(sk
, skb
, &timeo
, ssk
);
1803 return netlink_sendskb(sk
, skb
);
1805 EXPORT_SYMBOL(netlink_unicast
);
1807 struct sk_buff
*netlink_alloc_skb(struct sock
*ssk
, unsigned int size
,
1808 u32 dst_portid
, gfp_t gfp_mask
)
1810 #ifdef CONFIG_NETLINK_MMAP
1811 struct sock
*sk
= NULL
;
1812 struct sk_buff
*skb
;
1813 struct netlink_ring
*ring
;
1814 struct nl_mmap_hdr
*hdr
;
1815 unsigned int maxlen
;
1817 sk
= netlink_getsockbyportid(ssk
, dst_portid
);
1821 ring
= &nlk_sk(sk
)->rx_ring
;
1822 /* fast-path without atomic ops for common case: non-mmaped receiver */
1823 if (ring
->pg_vec
== NULL
)
1826 if (ring
->frame_size
- NL_MMAP_HDRLEN
< size
)
1829 skb
= alloc_skb_head(gfp_mask
);
1833 spin_lock_bh(&sk
->sk_receive_queue
.lock
);
1834 /* check again under lock */
1835 if (ring
->pg_vec
== NULL
)
1838 /* check again under lock */
1839 maxlen
= ring
->frame_size
- NL_MMAP_HDRLEN
;
1843 netlink_forward_ring(ring
);
1844 hdr
= netlink_current_frame(ring
, NL_MMAP_STATUS_UNUSED
);
1847 netlink_ring_setup_skb(skb
, sk
, ring
, hdr
);
1848 netlink_set_status(hdr
, NL_MMAP_STATUS_RESERVED
);
1849 atomic_inc(&ring
->pending
);
1850 netlink_increment_head(ring
);
1852 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
1857 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
1858 netlink_overrun(sk
);
1865 spin_unlock_bh(&sk
->sk_receive_queue
.lock
);
1870 return alloc_skb(size
, gfp_mask
);
1872 EXPORT_SYMBOL_GPL(netlink_alloc_skb
);
1874 int netlink_has_listeners(struct sock
*sk
, unsigned int group
)
1877 struct listeners
*listeners
;
1879 BUG_ON(!netlink_is_kernel(sk
));
1882 listeners
= rcu_dereference(nl_table
[sk
->sk_protocol
].listeners
);
1884 if (listeners
&& group
- 1 < nl_table
[sk
->sk_protocol
].groups
)
1885 res
= test_bit(group
- 1, listeners
->masks
);
1891 EXPORT_SYMBOL_GPL(netlink_has_listeners
);
1893 static int netlink_broadcast_deliver(struct sock
*sk
, struct sk_buff
*skb
)
1895 struct netlink_sock
*nlk
= nlk_sk(sk
);
1897 if (atomic_read(&sk
->sk_rmem_alloc
) <= sk
->sk_rcvbuf
&&
1898 !test_bit(NETLINK_CONGESTED
, &nlk
->state
)) {
1899 netlink_skb_set_owner_r(skb
, sk
);
1900 __netlink_sendskb(sk
, skb
);
1901 return atomic_read(&sk
->sk_rmem_alloc
) > (sk
->sk_rcvbuf
>> 1);
1906 struct netlink_broadcast_data
{
1907 struct sock
*exclude_sk
;
1912 int delivery_failure
;
1916 struct sk_buff
*skb
, *skb2
;
1917 int (*tx_filter
)(struct sock
*dsk
, struct sk_buff
*skb
, void *data
);
1921 static void do_one_broadcast(struct sock
*sk
,
1922 struct netlink_broadcast_data
*p
)
1924 struct netlink_sock
*nlk
= nlk_sk(sk
);
1927 if (p
->exclude_sk
== sk
)
1930 if (nlk
->portid
== p
->portid
|| p
->group
- 1 >= nlk
->ngroups
||
1931 !test_bit(p
->group
- 1, nlk
->groups
))
1934 if (!net_eq(sock_net(sk
), p
->net
))
1938 netlink_overrun(sk
);
1943 if (p
->skb2
== NULL
) {
1944 if (skb_shared(p
->skb
)) {
1945 p
->skb2
= skb_clone(p
->skb
, p
->allocation
);
1947 p
->skb2
= skb_get(p
->skb
);
1949 * skb ownership may have been set when
1950 * delivered to a previous socket.
1952 skb_orphan(p
->skb2
);
1955 if (p
->skb2
== NULL
) {
1956 netlink_overrun(sk
);
1957 /* Clone failed. Notify ALL listeners. */
1959 if (nlk
->flags
& NETLINK_BROADCAST_SEND_ERROR
)
1960 p
->delivery_failure
= 1;
1961 } else if (p
->tx_filter
&& p
->tx_filter(sk
, p
->skb2
, p
->tx_data
)) {
1964 } else if (sk_filter(sk
, p
->skb2
)) {
1967 } else if ((val
= netlink_broadcast_deliver(sk
, p
->skb2
)) < 0) {
1968 netlink_overrun(sk
);
1969 if (nlk
->flags
& NETLINK_BROADCAST_SEND_ERROR
)
1970 p
->delivery_failure
= 1;
1972 p
->congested
|= val
;
1979 int netlink_broadcast_filtered(struct sock
*ssk
, struct sk_buff
*skb
, u32 portid
,
1980 u32 group
, gfp_t allocation
,
1981 int (*filter
)(struct sock
*dsk
, struct sk_buff
*skb
, void *data
),
1984 struct net
*net
= sock_net(ssk
);
1985 struct netlink_broadcast_data info
;
1988 skb
= netlink_trim(skb
, allocation
);
1990 info
.exclude_sk
= ssk
;
1992 info
.portid
= portid
;
1995 info
.delivery_failure
= 0;
1998 info
.allocation
= allocation
;
2001 info
.tx_filter
= filter
;
2002 info
.tx_data
= filter_data
;
2004 /* While we sleep in clone, do not allow to change socket list */
2006 netlink_lock_table();
2008 sk_for_each_bound(sk
, &nl_table
[ssk
->sk_protocol
].mc_list
)
2009 do_one_broadcast(sk
, &info
);
2013 netlink_unlock_table();
2015 if (info
.delivery_failure
) {
2016 kfree_skb(info
.skb2
);
2019 consume_skb(info
.skb2
);
2021 if (info
.delivered
) {
2022 if (info
.congested
&& (allocation
& __GFP_WAIT
))
2028 EXPORT_SYMBOL(netlink_broadcast_filtered
);
2030 int netlink_broadcast(struct sock
*ssk
, struct sk_buff
*skb
, u32 portid
,
2031 u32 group
, gfp_t allocation
)
2033 return netlink_broadcast_filtered(ssk
, skb
, portid
, group
, allocation
,
2036 EXPORT_SYMBOL(netlink_broadcast
);
2038 struct netlink_set_err_data
{
2039 struct sock
*exclude_sk
;
2045 static int do_one_set_err(struct sock
*sk
, struct netlink_set_err_data
*p
)
2047 struct netlink_sock
*nlk
= nlk_sk(sk
);
2050 if (sk
== p
->exclude_sk
)
2053 if (!net_eq(sock_net(sk
), sock_net(p
->exclude_sk
)))
2056 if (nlk
->portid
== p
->portid
|| p
->group
- 1 >= nlk
->ngroups
||
2057 !test_bit(p
->group
- 1, nlk
->groups
))
2060 if (p
->code
== ENOBUFS
&& nlk
->flags
& NETLINK_RECV_NO_ENOBUFS
) {
2065 sk
->sk_err
= p
->code
;
2066 sk
->sk_error_report(sk
);
2072 * netlink_set_err - report error to broadcast listeners
2073 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2074 * @portid: the PORTID of a process that we want to skip (if any)
2075 * @group: the broadcast group that will notice the error
2076 * @code: error code, must be negative (as usual in kernelspace)
2078 * This function returns the number of broadcast listeners that have set the
2079 * NETLINK_RECV_NO_ENOBUFS socket option.
2081 int netlink_set_err(struct sock
*ssk
, u32 portid
, u32 group
, int code
)
2083 struct netlink_set_err_data info
;
2087 info
.exclude_sk
= ssk
;
2088 info
.portid
= portid
;
2090 /* sk->sk_err wants a positive error value */
2093 read_lock(&nl_table_lock
);
2095 sk_for_each_bound(sk
, &nl_table
[ssk
->sk_protocol
].mc_list
)
2096 ret
+= do_one_set_err(sk
, &info
);
2098 read_unlock(&nl_table_lock
);
2101 EXPORT_SYMBOL(netlink_set_err
);
2103 /* must be called with netlink table grabbed */
2104 static void netlink_update_socket_mc(struct netlink_sock
*nlk
,
2108 int old
, new = !!is_new
, subscriptions
;
2110 old
= test_bit(group
- 1, nlk
->groups
);
2111 subscriptions
= nlk
->subscriptions
- old
+ new;
2113 __set_bit(group
- 1, nlk
->groups
);
2115 __clear_bit(group
- 1, nlk
->groups
);
2116 netlink_update_subscriptions(&nlk
->sk
, subscriptions
);
2117 netlink_update_listeners(&nlk
->sk
);
2120 static int netlink_setsockopt(struct socket
*sock
, int level
, int optname
,
2121 char __user
*optval
, unsigned int optlen
)
2123 struct sock
*sk
= sock
->sk
;
2124 struct netlink_sock
*nlk
= nlk_sk(sk
);
2125 unsigned int val
= 0;
2128 if (level
!= SOL_NETLINK
)
2129 return -ENOPROTOOPT
;
2131 if (optname
!= NETLINK_RX_RING
&& optname
!= NETLINK_TX_RING
&&
2132 optlen
>= sizeof(int) &&
2133 get_user(val
, (unsigned int __user
*)optval
))
2137 case NETLINK_PKTINFO
:
2139 nlk
->flags
|= NETLINK_RECV_PKTINFO
;
2141 nlk
->flags
&= ~NETLINK_RECV_PKTINFO
;
2144 case NETLINK_ADD_MEMBERSHIP
:
2145 case NETLINK_DROP_MEMBERSHIP
: {
2146 if (!netlink_allowed(sock
, NL_CFG_F_NONROOT_RECV
))
2148 err
= netlink_realloc_groups(sk
);
2151 if (!val
|| val
- 1 >= nlk
->ngroups
)
2153 if (optname
== NETLINK_ADD_MEMBERSHIP
&& nlk
->netlink_bind
) {
2154 err
= nlk
->netlink_bind(sock_net(sk
), val
);
2158 netlink_table_grab();
2159 netlink_update_socket_mc(nlk
, val
,
2160 optname
== NETLINK_ADD_MEMBERSHIP
);
2161 netlink_table_ungrab();
2162 if (optname
== NETLINK_DROP_MEMBERSHIP
&& nlk
->netlink_unbind
)
2163 nlk
->netlink_unbind(sock_net(sk
), val
);
2168 case NETLINK_BROADCAST_ERROR
:
2170 nlk
->flags
|= NETLINK_BROADCAST_SEND_ERROR
;
2172 nlk
->flags
&= ~NETLINK_BROADCAST_SEND_ERROR
;
2175 case NETLINK_NO_ENOBUFS
:
2177 nlk
->flags
|= NETLINK_RECV_NO_ENOBUFS
;
2178 clear_bit(NETLINK_CONGESTED
, &nlk
->state
);
2179 wake_up_interruptible(&nlk
->wait
);
2181 nlk
->flags
&= ~NETLINK_RECV_NO_ENOBUFS
;
2185 #ifdef CONFIG_NETLINK_MMAP
2186 case NETLINK_RX_RING
:
2187 case NETLINK_TX_RING
: {
2188 struct nl_mmap_req req
;
2190 /* Rings might consume more memory than queue limits, require
2193 if (!capable(CAP_NET_ADMIN
))
2195 if (optlen
< sizeof(req
))
2197 if (copy_from_user(&req
, optval
, sizeof(req
)))
2199 err
= netlink_set_ring(sk
, &req
, false,
2200 optname
== NETLINK_TX_RING
);
2203 #endif /* CONFIG_NETLINK_MMAP */
2210 static int netlink_getsockopt(struct socket
*sock
, int level
, int optname
,
2211 char __user
*optval
, int __user
*optlen
)
2213 struct sock
*sk
= sock
->sk
;
2214 struct netlink_sock
*nlk
= nlk_sk(sk
);
2217 if (level
!= SOL_NETLINK
)
2218 return -ENOPROTOOPT
;
2220 if (get_user(len
, optlen
))
2226 case NETLINK_PKTINFO
:
2227 if (len
< sizeof(int))
2230 val
= nlk
->flags
& NETLINK_RECV_PKTINFO
? 1 : 0;
2231 if (put_user(len
, optlen
) ||
2232 put_user(val
, optval
))
2236 case NETLINK_BROADCAST_ERROR
:
2237 if (len
< sizeof(int))
2240 val
= nlk
->flags
& NETLINK_BROADCAST_SEND_ERROR
? 1 : 0;
2241 if (put_user(len
, optlen
) ||
2242 put_user(val
, optval
))
2246 case NETLINK_NO_ENOBUFS
:
2247 if (len
< sizeof(int))
2250 val
= nlk
->flags
& NETLINK_RECV_NO_ENOBUFS
? 1 : 0;
2251 if (put_user(len
, optlen
) ||
2252 put_user(val
, optval
))
2262 static void netlink_cmsg_recv_pktinfo(struct msghdr
*msg
, struct sk_buff
*skb
)
2264 struct nl_pktinfo info
;
2266 info
.group
= NETLINK_CB(skb
).dst_group
;
2267 put_cmsg(msg
, SOL_NETLINK
, NETLINK_PKTINFO
, sizeof(info
), &info
);
2270 static int netlink_sendmsg(struct socket
*sock
, struct msghdr
*msg
, size_t len
)
2272 struct sock
*sk
= sock
->sk
;
2273 struct netlink_sock
*nlk
= nlk_sk(sk
);
2274 DECLARE_SOCKADDR(struct sockaddr_nl
*, addr
, msg
->msg_name
);
2277 struct sk_buff
*skb
;
2279 struct scm_cookie scm
;
2280 u32 netlink_skb_flags
= 0;
2282 if (msg
->msg_flags
&MSG_OOB
)
2285 err
= scm_send(sock
, msg
, &scm
, true);
2289 if (msg
->msg_namelen
) {
2291 if (addr
->nl_family
!= AF_NETLINK
)
2293 dst_portid
= addr
->nl_pid
;
2294 dst_group
= ffs(addr
->nl_groups
);
2296 if ((dst_group
|| dst_portid
) &&
2297 !netlink_allowed(sock
, NL_CFG_F_NONROOT_SEND
))
2299 netlink_skb_flags
|= NETLINK_SKB_DST
;
2301 dst_portid
= nlk
->dst_portid
;
2302 dst_group
= nlk
->dst_group
;
2306 err
= netlink_autobind(sock
);
2311 /* It's a really convoluted way for userland to ask for mmaped
2312 * sendmsg(), but that's what we've got...
2314 if (netlink_tx_is_mmaped(sk
) &&
2315 msg
->msg_iter
.type
== ITER_IOVEC
&&
2316 msg
->msg_iter
.nr_segs
== 1 &&
2317 msg
->msg_iter
.iov
->iov_base
== NULL
) {
2318 err
= netlink_mmap_sendmsg(sk
, msg
, dst_portid
, dst_group
,
2324 if (len
> sk
->sk_sndbuf
- 32)
2327 skb
= netlink_alloc_large_skb(len
, dst_group
);
2331 NETLINK_CB(skb
).portid
= nlk
->portid
;
2332 NETLINK_CB(skb
).dst_group
= dst_group
;
2333 NETLINK_CB(skb
).creds
= scm
.creds
;
2334 NETLINK_CB(skb
).flags
= netlink_skb_flags
;
2337 if (memcpy_from_msg(skb_put(skb
, len
), msg
, len
)) {
2342 err
= security_netlink_send(sk
, skb
);
2349 atomic_inc(&skb
->users
);
2350 netlink_broadcast(sk
, skb
, dst_portid
, dst_group
, GFP_KERNEL
);
2352 err
= netlink_unicast(sk
, skb
, dst_portid
, msg
->msg_flags
&MSG_DONTWAIT
);
2359 static int netlink_recvmsg(struct socket
*sock
, struct msghdr
*msg
, size_t len
,
2362 struct scm_cookie scm
;
2363 struct sock
*sk
= sock
->sk
;
2364 struct netlink_sock
*nlk
= nlk_sk(sk
);
2365 int noblock
= flags
&MSG_DONTWAIT
;
2367 struct sk_buff
*skb
, *data_skb
;
2375 skb
= skb_recv_datagram(sk
, flags
, noblock
, &err
);
2381 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2382 if (unlikely(skb_shinfo(skb
)->frag_list
)) {
2384 * If this skb has a frag_list, then here that means that we
2385 * will have to use the frag_list skb's data for compat tasks
2386 * and the regular skb's data for normal (non-compat) tasks.
2388 * If we need to send the compat skb, assign it to the
2389 * 'data_skb' variable so that it will be used below for data
2390 * copying. We keep 'skb' for everything else, including
2391 * freeing both later.
2393 if (flags
& MSG_CMSG_COMPAT
)
2394 data_skb
= skb_shinfo(skb
)->frag_list
;
2398 /* Record the max length of recvmsg() calls for future allocations */
2399 nlk
->max_recvmsg_len
= max(nlk
->max_recvmsg_len
, len
);
2400 nlk
->max_recvmsg_len
= min_t(size_t, nlk
->max_recvmsg_len
,
2403 copied
= data_skb
->len
;
2405 msg
->msg_flags
|= MSG_TRUNC
;
2409 skb_reset_transport_header(data_skb
);
2410 err
= skb_copy_datagram_msg(data_skb
, 0, msg
, copied
);
2412 if (msg
->msg_name
) {
2413 DECLARE_SOCKADDR(struct sockaddr_nl
*, addr
, msg
->msg_name
);
2414 addr
->nl_family
= AF_NETLINK
;
2416 addr
->nl_pid
= NETLINK_CB(skb
).portid
;
2417 addr
->nl_groups
= netlink_group_mask(NETLINK_CB(skb
).dst_group
);
2418 msg
->msg_namelen
= sizeof(*addr
);
2421 if (nlk
->flags
& NETLINK_RECV_PKTINFO
)
2422 netlink_cmsg_recv_pktinfo(msg
, skb
);
2424 memset(&scm
, 0, sizeof(scm
));
2425 scm
.creds
= *NETLINK_CREDS(skb
);
2426 if (flags
& MSG_TRUNC
)
2427 copied
= data_skb
->len
;
2429 skb_free_datagram(sk
, skb
);
2431 if (nlk
->cb_running
&&
2432 atomic_read(&sk
->sk_rmem_alloc
) <= sk
->sk_rcvbuf
/ 2) {
2433 ret
= netlink_dump(sk
);
2436 sk
->sk_error_report(sk
);
2440 scm_recv(sock
, msg
, &scm
, flags
);
2442 netlink_rcv_wake(sk
);
2443 return err
? : copied
;
2446 static void netlink_data_ready(struct sock
*sk
)
2452 * We export these functions to other modules. They provide a
2453 * complete set of kernel non-blocking support for message
2458 __netlink_kernel_create(struct net
*net
, int unit
, struct module
*module
,
2459 struct netlink_kernel_cfg
*cfg
)
2461 struct socket
*sock
;
2463 struct netlink_sock
*nlk
;
2464 struct listeners
*listeners
= NULL
;
2465 struct mutex
*cb_mutex
= cfg
? cfg
->cb_mutex
: NULL
;
2466 unsigned int groups
;
2470 if (unit
< 0 || unit
>= MAX_LINKS
)
2473 if (sock_create_lite(PF_NETLINK
, SOCK_DGRAM
, unit
, &sock
))
2477 * We have to just have a reference on the net from sk, but don't
2478 * get_net it. Besides, we cannot get and then put the net here.
2479 * So we create one inside init_net and the move it to net.
2482 if (__netlink_create(&init_net
, sock
, cb_mutex
, unit
) < 0)
2483 goto out_sock_release_nosk
;
2486 sk_change_net(sk
, net
);
2488 if (!cfg
|| cfg
->groups
< 32)
2491 groups
= cfg
->groups
;
2493 listeners
= kzalloc(sizeof(*listeners
) + NLGRPSZ(groups
), GFP_KERNEL
);
2495 goto out_sock_release
;
2497 sk
->sk_data_ready
= netlink_data_ready
;
2498 if (cfg
&& cfg
->input
)
2499 nlk_sk(sk
)->netlink_rcv
= cfg
->input
;
2501 if (netlink_insert(sk
, 0))
2502 goto out_sock_release
;
2505 nlk
->flags
|= NETLINK_KERNEL_SOCKET
;
2507 netlink_table_grab();
2508 if (!nl_table
[unit
].registered
) {
2509 nl_table
[unit
].groups
= groups
;
2510 rcu_assign_pointer(nl_table
[unit
].listeners
, listeners
);
2511 nl_table
[unit
].cb_mutex
= cb_mutex
;
2512 nl_table
[unit
].module
= module
;
2514 nl_table
[unit
].bind
= cfg
->bind
;
2515 nl_table
[unit
].unbind
= cfg
->unbind
;
2516 nl_table
[unit
].flags
= cfg
->flags
;
2518 nl_table
[unit
].compare
= cfg
->compare
;
2520 nl_table
[unit
].registered
= 1;
2523 nl_table
[unit
].registered
++;
2525 netlink_table_ungrab();
2530 netlink_kernel_release(sk
);
2533 out_sock_release_nosk
:
2537 EXPORT_SYMBOL(__netlink_kernel_create
);
2540 netlink_kernel_release(struct sock
*sk
)
2542 sk_release_kernel(sk
);
2544 EXPORT_SYMBOL(netlink_kernel_release
);
2546 int __netlink_change_ngroups(struct sock
*sk
, unsigned int groups
)
2548 struct listeners
*new, *old
;
2549 struct netlink_table
*tbl
= &nl_table
[sk
->sk_protocol
];
2554 if (NLGRPSZ(tbl
->groups
) < NLGRPSZ(groups
)) {
2555 new = kzalloc(sizeof(*new) + NLGRPSZ(groups
), GFP_ATOMIC
);
2558 old
= nl_deref_protected(tbl
->listeners
);
2559 memcpy(new->masks
, old
->masks
, NLGRPSZ(tbl
->groups
));
2560 rcu_assign_pointer(tbl
->listeners
, new);
2562 kfree_rcu(old
, rcu
);
2564 tbl
->groups
= groups
;
2570 * netlink_change_ngroups - change number of multicast groups
2572 * This changes the number of multicast groups that are available
2573 * on a certain netlink family. Note that it is not possible to
2574 * change the number of groups to below 32. Also note that it does
2575 * not implicitly call netlink_clear_multicast_users() when the
2576 * number of groups is reduced.
2578 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2579 * @groups: The new number of groups.
2581 int netlink_change_ngroups(struct sock
*sk
, unsigned int groups
)
2585 netlink_table_grab();
2586 err
= __netlink_change_ngroups(sk
, groups
);
2587 netlink_table_ungrab();
2592 void __netlink_clear_multicast_users(struct sock
*ksk
, unsigned int group
)
2595 struct netlink_table
*tbl
= &nl_table
[ksk
->sk_protocol
];
2597 sk_for_each_bound(sk
, &tbl
->mc_list
)
2598 netlink_update_socket_mc(nlk_sk(sk
), group
, 0);
2602 __nlmsg_put(struct sk_buff
*skb
, u32 portid
, u32 seq
, int type
, int len
, int flags
)
2604 struct nlmsghdr
*nlh
;
2605 int size
= nlmsg_msg_size(len
);
2607 nlh
= (struct nlmsghdr
*)skb_put(skb
, NLMSG_ALIGN(size
));
2608 nlh
->nlmsg_type
= type
;
2609 nlh
->nlmsg_len
= size
;
2610 nlh
->nlmsg_flags
= flags
;
2611 nlh
->nlmsg_pid
= portid
;
2612 nlh
->nlmsg_seq
= seq
;
2613 if (!__builtin_constant_p(size
) || NLMSG_ALIGN(size
) - size
!= 0)
2614 memset(nlmsg_data(nlh
) + len
, 0, NLMSG_ALIGN(size
) - size
);
2617 EXPORT_SYMBOL(__nlmsg_put
);
2620 * It looks a bit ugly.
2621 * It would be better to create kernel thread.
2624 static int netlink_dump(struct sock
*sk
)
2626 struct netlink_sock
*nlk
= nlk_sk(sk
);
2627 struct netlink_callback
*cb
;
2628 struct sk_buff
*skb
= NULL
;
2629 struct nlmsghdr
*nlh
;
2630 int len
, err
= -ENOBUFS
;
2633 mutex_lock(nlk
->cb_mutex
);
2634 if (!nlk
->cb_running
) {
2640 alloc_size
= max_t(int, cb
->min_dump_alloc
, NLMSG_GOODSIZE
);
2642 if (!netlink_rx_is_mmaped(sk
) &&
2643 atomic_read(&sk
->sk_rmem_alloc
) >= sk
->sk_rcvbuf
)
2646 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2647 * required, but it makes sense to _attempt_ a 16K bytes allocation
2648 * to reduce number of system calls on dump operations, if user
2649 * ever provided a big enough buffer.
2651 if (alloc_size
< nlk
->max_recvmsg_len
) {
2652 skb
= netlink_alloc_skb(sk
,
2653 nlk
->max_recvmsg_len
,
2658 /* available room should be exact amount to avoid MSG_TRUNC */
2660 skb_reserve(skb
, skb_tailroom(skb
) -
2661 nlk
->max_recvmsg_len
);
2664 skb
= netlink_alloc_skb(sk
, alloc_size
, nlk
->portid
,
2668 netlink_skb_set_owner_r(skb
, sk
);
2670 len
= cb
->dump(skb
, cb
);
2673 mutex_unlock(nlk
->cb_mutex
);
2675 if (sk_filter(sk
, skb
))
2678 __netlink_sendskb(sk
, skb
);
2682 nlh
= nlmsg_put_answer(skb
, cb
, NLMSG_DONE
, sizeof(len
), NLM_F_MULTI
);
2686 nl_dump_check_consistent(cb
, nlh
);
2688 memcpy(nlmsg_data(nlh
), &len
, sizeof(len
));
2690 if (sk_filter(sk
, skb
))
2693 __netlink_sendskb(sk
, skb
);
2698 nlk
->cb_running
= false;
2699 mutex_unlock(nlk
->cb_mutex
);
2700 module_put(cb
->module
);
2701 consume_skb(cb
->skb
);
2705 mutex_unlock(nlk
->cb_mutex
);
2710 int __netlink_dump_start(struct sock
*ssk
, struct sk_buff
*skb
,
2711 const struct nlmsghdr
*nlh
,
2712 struct netlink_dump_control
*control
)
2714 struct netlink_callback
*cb
;
2716 struct netlink_sock
*nlk
;
2719 /* Memory mapped dump requests need to be copied to avoid looping
2720 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2721 * a reference to the skb.
2723 if (netlink_skb_is_mmaped(skb
)) {
2724 skb
= skb_copy(skb
, GFP_KERNEL
);
2728 atomic_inc(&skb
->users
);
2730 sk
= netlink_lookup(sock_net(ssk
), ssk
->sk_protocol
, NETLINK_CB(skb
).portid
);
2732 ret
= -ECONNREFUSED
;
2737 mutex_lock(nlk
->cb_mutex
);
2738 /* A dump is in progress... */
2739 if (nlk
->cb_running
) {
2743 /* add reference of module which cb->dump belongs to */
2744 if (!try_module_get(control
->module
)) {
2745 ret
= -EPROTONOSUPPORT
;
2750 memset(cb
, 0, sizeof(*cb
));
2751 cb
->dump
= control
->dump
;
2752 cb
->done
= control
->done
;
2754 cb
->data
= control
->data
;
2755 cb
->module
= control
->module
;
2756 cb
->min_dump_alloc
= control
->min_dump_alloc
;
2759 nlk
->cb_running
= true;
2761 mutex_unlock(nlk
->cb_mutex
);
2763 ret
= netlink_dump(sk
);
2769 /* We successfully started a dump, by returning -EINTR we
2770 * signal not to send ACK even if it was requested.
2776 mutex_unlock(nlk
->cb_mutex
);
2781 EXPORT_SYMBOL(__netlink_dump_start
);
2783 void netlink_ack(struct sk_buff
*in_skb
, struct nlmsghdr
*nlh
, int err
)
2785 struct sk_buff
*skb
;
2786 struct nlmsghdr
*rep
;
2787 struct nlmsgerr
*errmsg
;
2788 size_t payload
= sizeof(*errmsg
);
2790 /* error messages get the original request appened */
2792 payload
+= nlmsg_len(nlh
);
2794 skb
= netlink_alloc_skb(in_skb
->sk
, nlmsg_total_size(payload
),
2795 NETLINK_CB(in_skb
).portid
, GFP_KERNEL
);
2799 sk
= netlink_lookup(sock_net(in_skb
->sk
),
2800 in_skb
->sk
->sk_protocol
,
2801 NETLINK_CB(in_skb
).portid
);
2803 sk
->sk_err
= ENOBUFS
;
2804 sk
->sk_error_report(sk
);
2810 rep
= __nlmsg_put(skb
, NETLINK_CB(in_skb
).portid
, nlh
->nlmsg_seq
,
2811 NLMSG_ERROR
, payload
, 0);
2812 errmsg
= nlmsg_data(rep
);
2813 errmsg
->error
= err
;
2814 memcpy(&errmsg
->msg
, nlh
, err
? nlh
->nlmsg_len
: sizeof(*nlh
));
2815 netlink_unicast(in_skb
->sk
, skb
, NETLINK_CB(in_skb
).portid
, MSG_DONTWAIT
);
2817 EXPORT_SYMBOL(netlink_ack
);
2819 int netlink_rcv_skb(struct sk_buff
*skb
, int (*cb
)(struct sk_buff
*,
2822 struct nlmsghdr
*nlh
;
2825 while (skb
->len
>= nlmsg_total_size(0)) {
2828 nlh
= nlmsg_hdr(skb
);
2831 if (nlh
->nlmsg_len
< NLMSG_HDRLEN
|| skb
->len
< nlh
->nlmsg_len
)
2834 /* Only requests are handled by the kernel */
2835 if (!(nlh
->nlmsg_flags
& NLM_F_REQUEST
))
2838 /* Skip control messages */
2839 if (nlh
->nlmsg_type
< NLMSG_MIN_TYPE
)
2847 if (nlh
->nlmsg_flags
& NLM_F_ACK
|| err
)
2848 netlink_ack(skb
, nlh
, err
);
2851 msglen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
2852 if (msglen
> skb
->len
)
2854 skb_pull(skb
, msglen
);
2859 EXPORT_SYMBOL(netlink_rcv_skb
);
2862 * nlmsg_notify - send a notification netlink message
2863 * @sk: netlink socket to use
2864 * @skb: notification message
2865 * @portid: destination netlink portid for reports or 0
2866 * @group: destination multicast group or 0
2867 * @report: 1 to report back, 0 to disable
2868 * @flags: allocation flags
2870 int nlmsg_notify(struct sock
*sk
, struct sk_buff
*skb
, u32 portid
,
2871 unsigned int group
, int report
, gfp_t flags
)
2876 int exclude_portid
= 0;
2879 atomic_inc(&skb
->users
);
2880 exclude_portid
= portid
;
2883 /* errors reported via destination sk->sk_err, but propagate
2884 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2885 err
= nlmsg_multicast(sk
, skb
, exclude_portid
, group
, flags
);
2891 err2
= nlmsg_unicast(sk
, skb
, portid
);
2892 if (!err
|| err
== -ESRCH
)
2898 EXPORT_SYMBOL(nlmsg_notify
);
2900 #ifdef CONFIG_PROC_FS
2901 struct nl_seq_iter
{
2902 struct seq_net_private p
;
2903 struct rhashtable_iter hti
;
2907 static int netlink_walk_start(struct nl_seq_iter
*iter
)
2911 err
= rhashtable_walk_init(&nl_table
[iter
->link
].hash
, &iter
->hti
);
2913 iter
->link
= MAX_LINKS
;
2917 err
= rhashtable_walk_start(&iter
->hti
);
2918 return err
== -EAGAIN
? 0 : err
;
2921 static void netlink_walk_stop(struct nl_seq_iter
*iter
)
2923 rhashtable_walk_stop(&iter
->hti
);
2924 rhashtable_walk_exit(&iter
->hti
);
2927 static void *__netlink_seq_next(struct seq_file
*seq
)
2929 struct nl_seq_iter
*iter
= seq
->private;
2930 struct netlink_sock
*nlk
;
2936 nlk
= rhashtable_walk_next(&iter
->hti
);
2939 if (PTR_ERR(nlk
) == -EAGAIN
)
2948 netlink_walk_stop(iter
);
2949 if (++iter
->link
>= MAX_LINKS
)
2952 err
= netlink_walk_start(iter
);
2954 return ERR_PTR(err
);
2956 } while (sock_net(&nlk
->sk
) != seq_file_net(seq
));
2961 static void *netlink_seq_start(struct seq_file
*seq
, loff_t
*posp
)
2963 struct nl_seq_iter
*iter
= seq
->private;
2964 void *obj
= SEQ_START_TOKEN
;
2970 err
= netlink_walk_start(iter
);
2972 return ERR_PTR(err
);
2974 for (pos
= *posp
; pos
&& obj
&& !IS_ERR(obj
); pos
--)
2975 obj
= __netlink_seq_next(seq
);
2980 static void *netlink_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
2983 return __netlink_seq_next(seq
);
2986 static void netlink_seq_stop(struct seq_file
*seq
, void *v
)
2988 struct nl_seq_iter
*iter
= seq
->private;
2990 if (iter
->link
>= MAX_LINKS
)
2993 netlink_walk_stop(iter
);
2997 static int netlink_seq_show(struct seq_file
*seq
, void *v
)
2999 if (v
== SEQ_START_TOKEN
) {
3001 "sk Eth Pid Groups "
3002 "Rmem Wmem Dump Locks Drops Inode\n");
3005 struct netlink_sock
*nlk
= nlk_sk(s
);
3007 seq_printf(seq
, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
3011 nlk
->groups
? (u32
)nlk
->groups
[0] : 0,
3012 sk_rmem_alloc_get(s
),
3013 sk_wmem_alloc_get(s
),
3015 atomic_read(&s
->sk_refcnt
),
3016 atomic_read(&s
->sk_drops
),
3024 static const struct seq_operations netlink_seq_ops
= {
3025 .start
= netlink_seq_start
,
3026 .next
= netlink_seq_next
,
3027 .stop
= netlink_seq_stop
,
3028 .show
= netlink_seq_show
,
3032 static int netlink_seq_open(struct inode
*inode
, struct file
*file
)
3034 return seq_open_net(inode
, file
, &netlink_seq_ops
,
3035 sizeof(struct nl_seq_iter
));
3038 static const struct file_operations netlink_seq_fops
= {
3039 .owner
= THIS_MODULE
,
3040 .open
= netlink_seq_open
,
3042 .llseek
= seq_lseek
,
3043 .release
= seq_release_net
,
3048 int netlink_register_notifier(struct notifier_block
*nb
)
3050 return atomic_notifier_chain_register(&netlink_chain
, nb
);
3052 EXPORT_SYMBOL(netlink_register_notifier
);
3054 int netlink_unregister_notifier(struct notifier_block
*nb
)
3056 return atomic_notifier_chain_unregister(&netlink_chain
, nb
);
3058 EXPORT_SYMBOL(netlink_unregister_notifier
);
3060 static const struct proto_ops netlink_ops
= {
3061 .family
= PF_NETLINK
,
3062 .owner
= THIS_MODULE
,
3063 .release
= netlink_release
,
3064 .bind
= netlink_bind
,
3065 .connect
= netlink_connect
,
3066 .socketpair
= sock_no_socketpair
,
3067 .accept
= sock_no_accept
,
3068 .getname
= netlink_getname
,
3069 .poll
= netlink_poll
,
3070 .ioctl
= sock_no_ioctl
,
3071 .listen
= sock_no_listen
,
3072 .shutdown
= sock_no_shutdown
,
3073 .setsockopt
= netlink_setsockopt
,
3074 .getsockopt
= netlink_getsockopt
,
3075 .sendmsg
= netlink_sendmsg
,
3076 .recvmsg
= netlink_recvmsg
,
3077 .mmap
= netlink_mmap
,
3078 .sendpage
= sock_no_sendpage
,
3081 static const struct net_proto_family netlink_family_ops
= {
3082 .family
= PF_NETLINK
,
3083 .create
= netlink_create
,
3084 .owner
= THIS_MODULE
, /* for consistency 8) */
3087 static int __net_init
netlink_net_init(struct net
*net
)
3089 #ifdef CONFIG_PROC_FS
3090 if (!proc_create("netlink", 0, net
->proc_net
, &netlink_seq_fops
))
3096 static void __net_exit
netlink_net_exit(struct net
*net
)
3098 #ifdef CONFIG_PROC_FS
3099 remove_proc_entry("netlink", net
->proc_net
);
3103 static void __init
netlink_add_usersock_entry(void)
3105 struct listeners
*listeners
;
3108 listeners
= kzalloc(sizeof(*listeners
) + NLGRPSZ(groups
), GFP_KERNEL
);
3110 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3112 netlink_table_grab();
3114 nl_table
[NETLINK_USERSOCK
].groups
= groups
;
3115 rcu_assign_pointer(nl_table
[NETLINK_USERSOCK
].listeners
, listeners
);
3116 nl_table
[NETLINK_USERSOCK
].module
= THIS_MODULE
;
3117 nl_table
[NETLINK_USERSOCK
].registered
= 1;
3118 nl_table
[NETLINK_USERSOCK
].flags
= NL_CFG_F_NONROOT_SEND
;
3120 netlink_table_ungrab();
3123 static struct pernet_operations __net_initdata netlink_net_ops
= {
3124 .init
= netlink_net_init
,
3125 .exit
= netlink_net_exit
,
3128 static inline u32
netlink_hash(const void *data
, u32 len
, u32 seed
)
3130 const struct netlink_sock
*nlk
= data
;
3131 struct netlink_compare_arg arg
;
3133 netlink_compare_arg_init(&arg
, sock_net(&nlk
->sk
), nlk
->portid
);
3134 return jhash2((u32
*)&arg
, netlink_compare_arg_len
/ sizeof(u32
), seed
);
3137 static const struct rhashtable_params netlink_rhashtable_params
= {
3138 .head_offset
= offsetof(struct netlink_sock
, node
),
3139 .key_len
= netlink_compare_arg_len
,
3140 .obj_hashfn
= netlink_hash
,
3141 .obj_cmpfn
= netlink_compare
,
3143 .automatic_shrinking
= true,
3146 static int __init
netlink_proto_init(void)
3149 int err
= proto_register(&netlink_proto
, 0);
3154 BUILD_BUG_ON(sizeof(struct netlink_skb_parms
) > FIELD_SIZEOF(struct sk_buff
, cb
));
3156 nl_table
= kcalloc(MAX_LINKS
, sizeof(*nl_table
), GFP_KERNEL
);
3160 for (i
= 0; i
< MAX_LINKS
; i
++) {
3161 if (rhashtable_init(&nl_table
[i
].hash
,
3162 &netlink_rhashtable_params
) < 0) {
3164 rhashtable_destroy(&nl_table
[i
].hash
);
3170 INIT_LIST_HEAD(&netlink_tap_all
);
3172 netlink_add_usersock_entry();
3174 sock_register(&netlink_family_ops
);
3175 register_pernet_subsys(&netlink_net_ops
);
3176 /* The netlink device handler may be needed early. */
3181 panic("netlink_init: Cannot allocate nl_table\n");
3184 core_initcall(netlink_proto_init
);