aboutsummaryrefslogtreecommitdiffstats
path: root/net/netlink
diff options
context:
space:
mode:
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/Makefile5
-rw-r--r--net/netlink/af_netlink.c1454
2 files changed, 1459 insertions, 0 deletions
diff --git a/net/netlink/Makefile b/net/netlink/Makefile
new file mode 100644
index 000000000000..39d9c2dcd03c
--- /dev/null
+++ b/net/netlink/Makefile
@@ -0,0 +1,5 @@
1#
2# Makefile for the netlink driver.
3#
4
5obj-y := af_netlink.o
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
new file mode 100644
index 000000000000..1d5905c90cd4
--- /dev/null
+++ b/net/netlink/af_netlink.c
@@ -0,0 +1,1454 @@
1/*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@redhat.com>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 *
17 */
18
19#include <linux/config.h>
20#include <linux/module.h>
21
22#include <linux/kernel.h>
23#include <linux/init.h>
24#include <linux/major.h>
25#include <linux/signal.h>
26#include <linux/sched.h>
27#include <linux/errno.h>
28#include <linux/string.h>
29#include <linux/stat.h>
30#include <linux/socket.h>
31#include <linux/un.h>
32#include <linux/fcntl.h>
33#include <linux/termios.h>
34#include <linux/sockios.h>
35#include <linux/net.h>
36#include <linux/fs.h>
37#include <linux/slab.h>
38#include <asm/uaccess.h>
39#include <linux/skbuff.h>
40#include <linux/netdevice.h>
41#include <linux/rtnetlink.h>
42#include <linux/proc_fs.h>
43#include <linux/seq_file.h>
44#include <linux/smp_lock.h>
45#include <linux/notifier.h>
46#include <linux/security.h>
47#include <linux/jhash.h>
48#include <linux/jiffies.h>
49#include <linux/random.h>
50#include <linux/bitops.h>
51#include <linux/mm.h>
52#include <linux/types.h>
53#include <net/sock.h>
54#include <net/scm.h>
55
56#define Nprintk(a...)
57
58struct netlink_sock {
59 /* struct sock has to be the first member of netlink_sock */
60 struct sock sk;
61 u32 pid;
62 unsigned int groups;
63 u32 dst_pid;
64 unsigned int dst_groups;
65 unsigned long state;
66 wait_queue_head_t wait;
67 struct netlink_callback *cb;
68 spinlock_t cb_lock;
69 void (*data_ready)(struct sock *sk, int bytes);
70};
71
72static inline struct netlink_sock *nlk_sk(struct sock *sk)
73{
74 return (struct netlink_sock *)sk;
75}
76
77struct nl_pid_hash {
78 struct hlist_head *table;
79 unsigned long rehash_time;
80
81 unsigned int mask;
82 unsigned int shift;
83
84 unsigned int entries;
85 unsigned int max_shift;
86
87 u32 rnd;
88};
89
90struct netlink_table {
91 struct nl_pid_hash hash;
92 struct hlist_head mc_list;
93 unsigned int nl_nonroot;
94};
95
96static struct netlink_table *nl_table;
97
98static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
99
100static int netlink_dump(struct sock *sk);
101static void netlink_destroy_callback(struct netlink_callback *cb);
102
103static DEFINE_RWLOCK(nl_table_lock);
104static atomic_t nl_table_users = ATOMIC_INIT(0);
105
106static struct notifier_block *netlink_chain;
107
108static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
109{
110 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
111}
112
113static void netlink_sock_destruct(struct sock *sk)
114{
115 skb_queue_purge(&sk->sk_receive_queue);
116
117 if (!sock_flag(sk, SOCK_DEAD)) {
118 printk("Freeing alive netlink socket %p\n", sk);
119 return;
120 }
121 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
122 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
123 BUG_TRAP(!nlk_sk(sk)->cb);
124}
125
126/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
127 * Look, when several writers sleep and reader wakes them up, all but one
128 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
129 * this, _but_ remember, it adds useless work on UP machines.
130 */
131
132static void netlink_table_grab(void)
133{
134 write_lock_bh(&nl_table_lock);
135
136 if (atomic_read(&nl_table_users)) {
137 DECLARE_WAITQUEUE(wait, current);
138
139 add_wait_queue_exclusive(&nl_table_wait, &wait);
140 for(;;) {
141 set_current_state(TASK_UNINTERRUPTIBLE);
142 if (atomic_read(&nl_table_users) == 0)
143 break;
144 write_unlock_bh(&nl_table_lock);
145 schedule();
146 write_lock_bh(&nl_table_lock);
147 }
148
149 __set_current_state(TASK_RUNNING);
150 remove_wait_queue(&nl_table_wait, &wait);
151 }
152}
153
154static __inline__ void netlink_table_ungrab(void)
155{
156 write_unlock_bh(&nl_table_lock);
157 wake_up(&nl_table_wait);
158}
159
160static __inline__ void
161netlink_lock_table(void)
162{
163 /* read_lock() synchronizes us to netlink_table_grab */
164
165 read_lock(&nl_table_lock);
166 atomic_inc(&nl_table_users);
167 read_unlock(&nl_table_lock);
168}
169
170static __inline__ void
171netlink_unlock_table(void)
172{
173 if (atomic_dec_and_test(&nl_table_users))
174 wake_up(&nl_table_wait);
175}
176
177static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
178{
179 struct nl_pid_hash *hash = &nl_table[protocol].hash;
180 struct hlist_head *head;
181 struct sock *sk;
182 struct hlist_node *node;
183
184 read_lock(&nl_table_lock);
185 head = nl_pid_hashfn(hash, pid);
186 sk_for_each(sk, node, head) {
187 if (nlk_sk(sk)->pid == pid) {
188 sock_hold(sk);
189 goto found;
190 }
191 }
192 sk = NULL;
193found:
194 read_unlock(&nl_table_lock);
195 return sk;
196}
197
198static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
199{
200 if (size <= PAGE_SIZE)
201 return kmalloc(size, GFP_ATOMIC);
202 else
203 return (struct hlist_head *)
204 __get_free_pages(GFP_ATOMIC, get_order(size));
205}
206
207static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
208{
209 if (size <= PAGE_SIZE)
210 kfree(table);
211 else
212 free_pages((unsigned long)table, get_order(size));
213}
214
215static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
216{
217 unsigned int omask, mask, shift;
218 size_t osize, size;
219 struct hlist_head *otable, *table;
220 int i;
221
222 omask = mask = hash->mask;
223 osize = size = (mask + 1) * sizeof(*table);
224 shift = hash->shift;
225
226 if (grow) {
227 if (++shift > hash->max_shift)
228 return 0;
229 mask = mask * 2 + 1;
230 size *= 2;
231 }
232
233 table = nl_pid_hash_alloc(size);
234 if (!table)
235 return 0;
236
237 memset(table, 0, size);
238 otable = hash->table;
239 hash->table = table;
240 hash->mask = mask;
241 hash->shift = shift;
242 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
243
244 for (i = 0; i <= omask; i++) {
245 struct sock *sk;
246 struct hlist_node *node, *tmp;
247
248 sk_for_each_safe(sk, node, tmp, &otable[i])
249 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
250 }
251
252 nl_pid_hash_free(otable, osize);
253 hash->rehash_time = jiffies + 10 * 60 * HZ;
254 return 1;
255}
256
257static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
258{
259 int avg = hash->entries >> hash->shift;
260
261 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
262 return 1;
263
264 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
265 nl_pid_hash_rehash(hash, 0);
266 return 1;
267 }
268
269 return 0;
270}
271
272static struct proto_ops netlink_ops;
273
274static int netlink_insert(struct sock *sk, u32 pid)
275{
276 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
277 struct hlist_head *head;
278 int err = -EADDRINUSE;
279 struct sock *osk;
280 struct hlist_node *node;
281 int len;
282
283 netlink_table_grab();
284 head = nl_pid_hashfn(hash, pid);
285 len = 0;
286 sk_for_each(osk, node, head) {
287 if (nlk_sk(osk)->pid == pid)
288 break;
289 len++;
290 }
291 if (node)
292 goto err;
293
294 err = -EBUSY;
295 if (nlk_sk(sk)->pid)
296 goto err;
297
298 err = -ENOMEM;
299 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
300 goto err;
301
302 if (len && nl_pid_hash_dilute(hash, len))
303 head = nl_pid_hashfn(hash, pid);
304 hash->entries++;
305 nlk_sk(sk)->pid = pid;
306 sk_add_node(sk, head);
307 err = 0;
308
309err:
310 netlink_table_ungrab();
311 return err;
312}
313
314static void netlink_remove(struct sock *sk)
315{
316 netlink_table_grab();
317 nl_table[sk->sk_protocol].hash.entries--;
318 sk_del_node_init(sk);
319 if (nlk_sk(sk)->groups)
320 __sk_del_bind_node(sk);
321 netlink_table_ungrab();
322}
323
324static struct proto netlink_proto = {
325 .name = "NETLINK",
326 .owner = THIS_MODULE,
327 .obj_size = sizeof(struct netlink_sock),
328};
329
330static int netlink_create(struct socket *sock, int protocol)
331{
332 struct sock *sk;
333 struct netlink_sock *nlk;
334
335 sock->state = SS_UNCONNECTED;
336
337 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
338 return -ESOCKTNOSUPPORT;
339
340 if (protocol<0 || protocol >= MAX_LINKS)
341 return -EPROTONOSUPPORT;
342
343 sock->ops = &netlink_ops;
344
345 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
346 if (!sk)
347 return -ENOMEM;
348
349 sock_init_data(sock, sk);
350
351 nlk = nlk_sk(sk);
352
353 spin_lock_init(&nlk->cb_lock);
354 init_waitqueue_head(&nlk->wait);
355 sk->sk_destruct = netlink_sock_destruct;
356
357 sk->sk_protocol = protocol;
358 return 0;
359}
360
361static int netlink_release(struct socket *sock)
362{
363 struct sock *sk = sock->sk;
364 struct netlink_sock *nlk;
365
366 if (!sk)
367 return 0;
368
369 netlink_remove(sk);
370 nlk = nlk_sk(sk);
371
372 spin_lock(&nlk->cb_lock);
373 if (nlk->cb) {
374 nlk->cb->done(nlk->cb);
375 netlink_destroy_callback(nlk->cb);
376 nlk->cb = NULL;
377 __sock_put(sk);
378 }
379 spin_unlock(&nlk->cb_lock);
380
381 /* OK. Socket is unlinked, and, therefore,
382 no new packets will arrive */
383
384 sock_orphan(sk);
385 sock->sk = NULL;
386 wake_up_interruptible_all(&nlk->wait);
387
388 skb_queue_purge(&sk->sk_write_queue);
389
390 if (nlk->pid && !nlk->groups) {
391 struct netlink_notify n = {
392 .protocol = sk->sk_protocol,
393 .pid = nlk->pid,
394 };
395 notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
396 }
397
398 sock_put(sk);
399 return 0;
400}
401
402static int netlink_autobind(struct socket *sock)
403{
404 struct sock *sk = sock->sk;
405 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
406 struct hlist_head *head;
407 struct sock *osk;
408 struct hlist_node *node;
409 s32 pid = current->pid;
410 int err;
411 static s32 rover = -4097;
412
413retry:
414 cond_resched();
415 netlink_table_grab();
416 head = nl_pid_hashfn(hash, pid);
417 sk_for_each(osk, node, head) {
418 if (nlk_sk(osk)->pid == pid) {
419 /* Bind collision, search negative pid values. */
420 pid = rover--;
421 if (rover > -4097)
422 rover = -4097;
423 netlink_table_ungrab();
424 goto retry;
425 }
426 }
427 netlink_table_ungrab();
428
429 err = netlink_insert(sk, pid);
430 if (err == -EADDRINUSE)
431 goto retry;
432 return 0;
433}
434
435static inline int netlink_capable(struct socket *sock, unsigned int flag)
436{
437 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
438 capable(CAP_NET_ADMIN);
439}
440
441static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
442{
443 struct sock *sk = sock->sk;
444 struct netlink_sock *nlk = nlk_sk(sk);
445 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
446 int err;
447
448 if (nladdr->nl_family != AF_NETLINK)
449 return -EINVAL;
450
451 /* Only superuser is allowed to listen multicasts */
452 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_RECV))
453 return -EPERM;
454
455 if (nlk->pid) {
456 if (nladdr->nl_pid != nlk->pid)
457 return -EINVAL;
458 } else {
459 err = nladdr->nl_pid ?
460 netlink_insert(sk, nladdr->nl_pid) :
461 netlink_autobind(sock);
462 if (err)
463 return err;
464 }
465
466 if (!nladdr->nl_groups && !nlk->groups)
467 return 0;
468
469 netlink_table_grab();
470 if (nlk->groups && !nladdr->nl_groups)
471 __sk_del_bind_node(sk);
472 else if (!nlk->groups && nladdr->nl_groups)
473 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
474 nlk->groups = nladdr->nl_groups;
475 netlink_table_ungrab();
476
477 return 0;
478}
479
480static int netlink_connect(struct socket *sock, struct sockaddr *addr,
481 int alen, int flags)
482{
483 int err = 0;
484 struct sock *sk = sock->sk;
485 struct netlink_sock *nlk = nlk_sk(sk);
486 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
487
488 if (addr->sa_family == AF_UNSPEC) {
489 sk->sk_state = NETLINK_UNCONNECTED;
490 nlk->dst_pid = 0;
491 nlk->dst_groups = 0;
492 return 0;
493 }
494 if (addr->sa_family != AF_NETLINK)
495 return -EINVAL;
496
497 /* Only superuser is allowed to send multicasts */
498 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
499 return -EPERM;
500
501 if (!nlk->pid)
502 err = netlink_autobind(sock);
503
504 if (err == 0) {
505 sk->sk_state = NETLINK_CONNECTED;
506 nlk->dst_pid = nladdr->nl_pid;
507 nlk->dst_groups = nladdr->nl_groups;
508 }
509
510 return err;
511}
512
513static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
514{
515 struct sock *sk = sock->sk;
516 struct netlink_sock *nlk = nlk_sk(sk);
517 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
518
519 nladdr->nl_family = AF_NETLINK;
520 nladdr->nl_pad = 0;
521 *addr_len = sizeof(*nladdr);
522
523 if (peer) {
524 nladdr->nl_pid = nlk->dst_pid;
525 nladdr->nl_groups = nlk->dst_groups;
526 } else {
527 nladdr->nl_pid = nlk->pid;
528 nladdr->nl_groups = nlk->groups;
529 }
530 return 0;
531}
532
533static void netlink_overrun(struct sock *sk)
534{
535 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
536 sk->sk_err = ENOBUFS;
537 sk->sk_error_report(sk);
538 }
539}
540
541static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
542{
543 int protocol = ssk->sk_protocol;
544 struct sock *sock;
545 struct netlink_sock *nlk;
546
547 sock = netlink_lookup(protocol, pid);
548 if (!sock)
549 return ERR_PTR(-ECONNREFUSED);
550
551 /* Don't bother queuing skb if kernel socket has no input function */
552 nlk = nlk_sk(sock);
553 if ((nlk->pid == 0 && !nlk->data_ready) ||
554 (sock->sk_state == NETLINK_CONNECTED &&
555 nlk->dst_pid != nlk_sk(ssk)->pid)) {
556 sock_put(sock);
557 return ERR_PTR(-ECONNREFUSED);
558 }
559 return sock;
560}
561
562struct sock *netlink_getsockbyfilp(struct file *filp)
563{
564 struct inode *inode = filp->f_dentry->d_inode;
565 struct sock *sock;
566
567 if (!S_ISSOCK(inode->i_mode))
568 return ERR_PTR(-ENOTSOCK);
569
570 sock = SOCKET_I(inode)->sk;
571 if (sock->sk_family != AF_NETLINK)
572 return ERR_PTR(-EINVAL);
573
574 sock_hold(sock);
575 return sock;
576}
577
578/*
579 * Attach a skb to a netlink socket.
580 * The caller must hold a reference to the destination socket. On error, the
581 * reference is dropped. The skb is not send to the destination, just all
582 * all error checks are performed and memory in the queue is reserved.
583 * Return values:
584 * < 0: error. skb freed, reference to sock dropped.
585 * 0: continue
586 * 1: repeat lookup - reference dropped while waiting for socket memory.
587 */
588int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo)
589{
590 struct netlink_sock *nlk;
591
592 nlk = nlk_sk(sk);
593
594 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
595 test_bit(0, &nlk->state)) {
596 DECLARE_WAITQUEUE(wait, current);
597 if (!timeo) {
598 if (!nlk->pid)
599 netlink_overrun(sk);
600 sock_put(sk);
601 kfree_skb(skb);
602 return -EAGAIN;
603 }
604
605 __set_current_state(TASK_INTERRUPTIBLE);
606 add_wait_queue(&nlk->wait, &wait);
607
608 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
609 test_bit(0, &nlk->state)) &&
610 !sock_flag(sk, SOCK_DEAD))
611 timeo = schedule_timeout(timeo);
612
613 __set_current_state(TASK_RUNNING);
614 remove_wait_queue(&nlk->wait, &wait);
615 sock_put(sk);
616
617 if (signal_pending(current)) {
618 kfree_skb(skb);
619 return sock_intr_errno(timeo);
620 }
621 return 1;
622 }
623 skb_set_owner_r(skb, sk);
624 return 0;
625}
626
627int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
628{
629 struct netlink_sock *nlk;
630 int len = skb->len;
631
632 nlk = nlk_sk(sk);
633
634 skb_queue_tail(&sk->sk_receive_queue, skb);
635 sk->sk_data_ready(sk, len);
636 sock_put(sk);
637 return len;
638}
639
640void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
641{
642 kfree_skb(skb);
643 sock_put(sk);
644}
645
646static inline struct sk_buff *netlink_trim(struct sk_buff *skb, int allocation)
647{
648 int delta;
649
650 skb_orphan(skb);
651
652 delta = skb->end - skb->tail;
653 if (delta * 2 < skb->truesize)
654 return skb;
655
656 if (skb_shared(skb)) {
657 struct sk_buff *nskb = skb_clone(skb, allocation);
658 if (!nskb)
659 return skb;
660 kfree_skb(skb);
661 skb = nskb;
662 }
663
664 if (!pskb_expand_head(skb, 0, -delta, allocation))
665 skb->truesize -= delta;
666
667 return skb;
668}
669
670int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
671{
672 struct sock *sk;
673 int err;
674 long timeo;
675
676 skb = netlink_trim(skb, gfp_any());
677
678 timeo = sock_sndtimeo(ssk, nonblock);
679retry:
680 sk = netlink_getsockbypid(ssk, pid);
681 if (IS_ERR(sk)) {
682 kfree_skb(skb);
683 return PTR_ERR(sk);
684 }
685 err = netlink_attachskb(sk, skb, nonblock, timeo);
686 if (err == 1)
687 goto retry;
688 if (err)
689 return err;
690
691 return netlink_sendskb(sk, skb, ssk->sk_protocol);
692}
693
694static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
695{
696 struct netlink_sock *nlk = nlk_sk(sk);
697
698 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
699 !test_bit(0, &nlk->state)) {
700 skb_set_owner_r(skb, sk);
701 skb_queue_tail(&sk->sk_receive_queue, skb);
702 sk->sk_data_ready(sk, skb->len);
703 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
704 }
705 return -1;
706}
707
708struct netlink_broadcast_data {
709 struct sock *exclude_sk;
710 u32 pid;
711 u32 group;
712 int failure;
713 int congested;
714 int delivered;
715 int allocation;
716 struct sk_buff *skb, *skb2;
717};
718
719static inline int do_one_broadcast(struct sock *sk,
720 struct netlink_broadcast_data *p)
721{
722 struct netlink_sock *nlk = nlk_sk(sk);
723 int val;
724
725 if (p->exclude_sk == sk)
726 goto out;
727
728 if (nlk->pid == p->pid || !(nlk->groups & p->group))
729 goto out;
730
731 if (p->failure) {
732 netlink_overrun(sk);
733 goto out;
734 }
735
736 sock_hold(sk);
737 if (p->skb2 == NULL) {
738 if (atomic_read(&p->skb->users) != 1) {
739 p->skb2 = skb_clone(p->skb, p->allocation);
740 } else {
741 p->skb2 = p->skb;
742 atomic_inc(&p->skb->users);
743 }
744 }
745 if (p->skb2 == NULL) {
746 netlink_overrun(sk);
747 /* Clone failed. Notify ALL listeners. */
748 p->failure = 1;
749 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
750 netlink_overrun(sk);
751 } else {
752 p->congested |= val;
753 p->delivered = 1;
754 p->skb2 = NULL;
755 }
756 sock_put(sk);
757
758out:
759 return 0;
760}
761
762int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
763 u32 group, int allocation)
764{
765 struct netlink_broadcast_data info;
766 struct hlist_node *node;
767 struct sock *sk;
768
769 skb = netlink_trim(skb, allocation);
770
771 info.exclude_sk = ssk;
772 info.pid = pid;
773 info.group = group;
774 info.failure = 0;
775 info.congested = 0;
776 info.delivered = 0;
777 info.allocation = allocation;
778 info.skb = skb;
779 info.skb2 = NULL;
780
781 /* While we sleep in clone, do not allow to change socket list */
782
783 netlink_lock_table();
784
785 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
786 do_one_broadcast(sk, &info);
787
788 netlink_unlock_table();
789
790 if (info.skb2)
791 kfree_skb(info.skb2);
792 kfree_skb(skb);
793
794 if (info.delivered) {
795 if (info.congested && (allocation & __GFP_WAIT))
796 yield();
797 return 0;
798 }
799 if (info.failure)
800 return -ENOBUFS;
801 return -ESRCH;
802}
803
804struct netlink_set_err_data {
805 struct sock *exclude_sk;
806 u32 pid;
807 u32 group;
808 int code;
809};
810
811static inline int do_one_set_err(struct sock *sk,
812 struct netlink_set_err_data *p)
813{
814 struct netlink_sock *nlk = nlk_sk(sk);
815
816 if (sk == p->exclude_sk)
817 goto out;
818
819 if (nlk->pid == p->pid || !(nlk->groups & p->group))
820 goto out;
821
822 sk->sk_err = p->code;
823 sk->sk_error_report(sk);
824out:
825 return 0;
826}
827
828void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
829{
830 struct netlink_set_err_data info;
831 struct hlist_node *node;
832 struct sock *sk;
833
834 info.exclude_sk = ssk;
835 info.pid = pid;
836 info.group = group;
837 info.code = code;
838
839 read_lock(&nl_table_lock);
840
841 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
842 do_one_set_err(sk, &info);
843
844 read_unlock(&nl_table_lock);
845}
846
847static inline void netlink_rcv_wake(struct sock *sk)
848{
849 struct netlink_sock *nlk = nlk_sk(sk);
850
851 if (!skb_queue_len(&sk->sk_receive_queue))
852 clear_bit(0, &nlk->state);
853 if (!test_bit(0, &nlk->state))
854 wake_up_interruptible(&nlk->wait);
855}
856
857static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
858 struct msghdr *msg, size_t len)
859{
860 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
861 struct sock *sk = sock->sk;
862 struct netlink_sock *nlk = nlk_sk(sk);
863 struct sockaddr_nl *addr=msg->msg_name;
864 u32 dst_pid;
865 u32 dst_groups;
866 struct sk_buff *skb;
867 int err;
868 struct scm_cookie scm;
869
870 if (msg->msg_flags&MSG_OOB)
871 return -EOPNOTSUPP;
872
873 if (NULL == siocb->scm)
874 siocb->scm = &scm;
875 err = scm_send(sock, msg, siocb->scm);
876 if (err < 0)
877 return err;
878
879 if (msg->msg_namelen) {
880 if (addr->nl_family != AF_NETLINK)
881 return -EINVAL;
882 dst_pid = addr->nl_pid;
883 dst_groups = addr->nl_groups;
884 if (dst_groups && !netlink_capable(sock, NL_NONROOT_SEND))
885 return -EPERM;
886 } else {
887 dst_pid = nlk->dst_pid;
888 dst_groups = nlk->dst_groups;
889 }
890
891 if (!nlk->pid) {
892 err = netlink_autobind(sock);
893 if (err)
894 goto out;
895 }
896
897 err = -EMSGSIZE;
898 if (len > sk->sk_sndbuf - 32)
899 goto out;
900 err = -ENOBUFS;
901 skb = alloc_skb(len, GFP_KERNEL);
902 if (skb==NULL)
903 goto out;
904
905 NETLINK_CB(skb).pid = nlk->pid;
906 NETLINK_CB(skb).groups = nlk->groups;
907 NETLINK_CB(skb).dst_pid = dst_pid;
908 NETLINK_CB(skb).dst_groups = dst_groups;
909 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
910
911 /* What can I do? Netlink is asynchronous, so that
912 we will have to save current capabilities to
913 check them, when this message will be delivered
914 to corresponding kernel module. --ANK (980802)
915 */
916
917 err = -EFAULT;
918 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
919 kfree_skb(skb);
920 goto out;
921 }
922
923 err = security_netlink_send(sk, skb);
924 if (err) {
925 kfree_skb(skb);
926 goto out;
927 }
928
929 if (dst_groups) {
930 atomic_inc(&skb->users);
931 netlink_broadcast(sk, skb, dst_pid, dst_groups, GFP_KERNEL);
932 }
933 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
934
935out:
936 return err;
937}
938
939static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
940 struct msghdr *msg, size_t len,
941 int flags)
942{
943 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
944 struct scm_cookie scm;
945 struct sock *sk = sock->sk;
946 struct netlink_sock *nlk = nlk_sk(sk);
947 int noblock = flags&MSG_DONTWAIT;
948 size_t copied;
949 struct sk_buff *skb;
950 int err;
951
952 if (flags&MSG_OOB)
953 return -EOPNOTSUPP;
954
955 copied = 0;
956
957 skb = skb_recv_datagram(sk,flags,noblock,&err);
958 if (skb==NULL)
959 goto out;
960
961 msg->msg_namelen = 0;
962
963 copied = skb->len;
964 if (len < copied) {
965 msg->msg_flags |= MSG_TRUNC;
966 copied = len;
967 }
968
969 skb->h.raw = skb->data;
970 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
971
972 if (msg->msg_name) {
973 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
974 addr->nl_family = AF_NETLINK;
975 addr->nl_pad = 0;
976 addr->nl_pid = NETLINK_CB(skb).pid;
977 addr->nl_groups = NETLINK_CB(skb).dst_groups;
978 msg->msg_namelen = sizeof(*addr);
979 }
980
981 if (NULL == siocb->scm) {
982 memset(&scm, 0, sizeof(scm));
983 siocb->scm = &scm;
984 }
985 siocb->scm->creds = *NETLINK_CREDS(skb);
986 skb_free_datagram(sk, skb);
987
988 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
989 netlink_dump(sk);
990
991 scm_recv(sock, msg, siocb->scm, flags);
992
993out:
994 netlink_rcv_wake(sk);
995 return err ? : copied;
996}
997
998static void netlink_data_ready(struct sock *sk, int len)
999{
1000 struct netlink_sock *nlk = nlk_sk(sk);
1001
1002 if (nlk->data_ready)
1003 nlk->data_ready(sk, len);
1004 netlink_rcv_wake(sk);
1005}
1006
1007/*
1008 * We export these functions to other modules. They provide a
1009 * complete set of kernel non-blocking support for message
1010 * queueing.
1011 */
1012
1013struct sock *
1014netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len))
1015{
1016 struct socket *sock;
1017 struct sock *sk;
1018
1019 if (!nl_table)
1020 return NULL;
1021
1022 if (unit<0 || unit>=MAX_LINKS)
1023 return NULL;
1024
1025 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1026 return NULL;
1027
1028 if (netlink_create(sock, unit) < 0) {
1029 sock_release(sock);
1030 return NULL;
1031 }
1032 sk = sock->sk;
1033 sk->sk_data_ready = netlink_data_ready;
1034 if (input)
1035 nlk_sk(sk)->data_ready = input;
1036
1037 if (netlink_insert(sk, 0)) {
1038 sock_release(sock);
1039 return NULL;
1040 }
1041 return sk;
1042}
1043
1044void netlink_set_nonroot(int protocol, unsigned int flags)
1045{
1046 if ((unsigned int)protocol < MAX_LINKS)
1047 nl_table[protocol].nl_nonroot = flags;
1048}
1049
1050static void netlink_destroy_callback(struct netlink_callback *cb)
1051{
1052 if (cb->skb)
1053 kfree_skb(cb->skb);
1054 kfree(cb);
1055}
1056
1057/*
1058 * It looks a bit ugly.
1059 * It would be better to create kernel thread.
1060 */
1061
1062static int netlink_dump(struct sock *sk)
1063{
1064 struct netlink_sock *nlk = nlk_sk(sk);
1065 struct netlink_callback *cb;
1066 struct sk_buff *skb;
1067 struct nlmsghdr *nlh;
1068 int len;
1069
1070 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1071 if (!skb)
1072 return -ENOBUFS;
1073
1074 spin_lock(&nlk->cb_lock);
1075
1076 cb = nlk->cb;
1077 if (cb == NULL) {
1078 spin_unlock(&nlk->cb_lock);
1079 kfree_skb(skb);
1080 return -EINVAL;
1081 }
1082
1083 len = cb->dump(skb, cb);
1084
1085 if (len > 0) {
1086 spin_unlock(&nlk->cb_lock);
1087 skb_queue_tail(&sk->sk_receive_queue, skb);
1088 sk->sk_data_ready(sk, len);
1089 return 0;
1090 }
1091
1092 nlh = __nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, NLMSG_DONE, sizeof(int));
1093 nlh->nlmsg_flags |= NLM_F_MULTI;
1094 memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
1095 skb_queue_tail(&sk->sk_receive_queue, skb);
1096 sk->sk_data_ready(sk, skb->len);
1097
1098 cb->done(cb);
1099 nlk->cb = NULL;
1100 spin_unlock(&nlk->cb_lock);
1101
1102 netlink_destroy_callback(cb);
1103 __sock_put(sk);
1104 return 0;
1105}
1106
1107int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1108 struct nlmsghdr *nlh,
1109 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1110 int (*done)(struct netlink_callback*))
1111{
1112 struct netlink_callback *cb;
1113 struct sock *sk;
1114 struct netlink_sock *nlk;
1115
1116 cb = kmalloc(sizeof(*cb), GFP_KERNEL);
1117 if (cb == NULL)
1118 return -ENOBUFS;
1119
1120 memset(cb, 0, sizeof(*cb));
1121 cb->dump = dump;
1122 cb->done = done;
1123 cb->nlh = nlh;
1124 atomic_inc(&skb->users);
1125 cb->skb = skb;
1126
1127 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1128 if (sk == NULL) {
1129 netlink_destroy_callback(cb);
1130 return -ECONNREFUSED;
1131 }
1132 nlk = nlk_sk(sk);
1133 /* A dump is in progress... */
1134 spin_lock(&nlk->cb_lock);
1135 if (nlk->cb) {
1136 spin_unlock(&nlk->cb_lock);
1137 netlink_destroy_callback(cb);
1138 sock_put(sk);
1139 return -EBUSY;
1140 }
1141 nlk->cb = cb;
1142 sock_hold(sk);
1143 spin_unlock(&nlk->cb_lock);
1144
1145 netlink_dump(sk);
1146 sock_put(sk);
1147 return 0;
1148}
1149
1150void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1151{
1152 struct sk_buff *skb;
1153 struct nlmsghdr *rep;
1154 struct nlmsgerr *errmsg;
1155 int size;
1156
1157 if (err == 0)
1158 size = NLMSG_SPACE(sizeof(struct nlmsgerr));
1159 else
1160 size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len));
1161
1162 skb = alloc_skb(size, GFP_KERNEL);
1163 if (!skb) {
1164 struct sock *sk;
1165
1166 sk = netlink_lookup(in_skb->sk->sk_protocol,
1167 NETLINK_CB(in_skb).pid);
1168 if (sk) {
1169 sk->sk_err = ENOBUFS;
1170 sk->sk_error_report(sk);
1171 sock_put(sk);
1172 }
1173 return;
1174 }
1175
1176 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1177 NLMSG_ERROR, sizeof(struct nlmsgerr));
1178 errmsg = NLMSG_DATA(rep);
1179 errmsg->error = err;
1180 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr));
1181 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1182}
1183
1184
1185#ifdef CONFIG_PROC_FS
1186struct nl_seq_iter {
1187 int link;
1188 int hash_idx;
1189};
1190
1191static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1192{
1193 struct nl_seq_iter *iter = seq->private;
1194 int i, j;
1195 struct sock *s;
1196 struct hlist_node *node;
1197 loff_t off = 0;
1198
1199 for (i=0; i<MAX_LINKS; i++) {
1200 struct nl_pid_hash *hash = &nl_table[i].hash;
1201
1202 for (j = 0; j <= hash->mask; j++) {
1203 sk_for_each(s, node, &hash->table[j]) {
1204 if (off == pos) {
1205 iter->link = i;
1206 iter->hash_idx = j;
1207 return s;
1208 }
1209 ++off;
1210 }
1211 }
1212 }
1213 return NULL;
1214}
1215
1216static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1217{
1218 read_lock(&nl_table_lock);
1219 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1220}
1221
1222static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1223{
1224 struct sock *s;
1225 struct nl_seq_iter *iter;
1226 int i, j;
1227
1228 ++*pos;
1229
1230 if (v == SEQ_START_TOKEN)
1231 return netlink_seq_socket_idx(seq, 0);
1232
1233 s = sk_next(v);
1234 if (s)
1235 return s;
1236
1237 iter = seq->private;
1238 i = iter->link;
1239 j = iter->hash_idx + 1;
1240
1241 do {
1242 struct nl_pid_hash *hash = &nl_table[i].hash;
1243
1244 for (; j <= hash->mask; j++) {
1245 s = sk_head(&hash->table[j]);
1246 if (s) {
1247 iter->link = i;
1248 iter->hash_idx = j;
1249 return s;
1250 }
1251 }
1252
1253 j = 0;
1254 } while (++i < MAX_LINKS);
1255
1256 return NULL;
1257}
1258
1259static void netlink_seq_stop(struct seq_file *seq, void *v)
1260{
1261 read_unlock(&nl_table_lock);
1262}
1263
1264
1265static int netlink_seq_show(struct seq_file *seq, void *v)
1266{
1267 if (v == SEQ_START_TOKEN)
1268 seq_puts(seq,
1269 "sk Eth Pid Groups "
1270 "Rmem Wmem Dump Locks\n");
1271 else {
1272 struct sock *s = v;
1273 struct netlink_sock *nlk = nlk_sk(s);
1274
1275 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1276 s,
1277 s->sk_protocol,
1278 nlk->pid,
1279 nlk->groups,
1280 atomic_read(&s->sk_rmem_alloc),
1281 atomic_read(&s->sk_wmem_alloc),
1282 nlk->cb,
1283 atomic_read(&s->sk_refcnt)
1284 );
1285
1286 }
1287 return 0;
1288}
1289
1290static struct seq_operations netlink_seq_ops = {
1291 .start = netlink_seq_start,
1292 .next = netlink_seq_next,
1293 .stop = netlink_seq_stop,
1294 .show = netlink_seq_show,
1295};
1296
1297
1298static int netlink_seq_open(struct inode *inode, struct file *file)
1299{
1300 struct seq_file *seq;
1301 struct nl_seq_iter *iter;
1302 int err;
1303
1304 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
1305 if (!iter)
1306 return -ENOMEM;
1307
1308 err = seq_open(file, &netlink_seq_ops);
1309 if (err) {
1310 kfree(iter);
1311 return err;
1312 }
1313
1314 memset(iter, 0, sizeof(*iter));
1315 seq = file->private_data;
1316 seq->private = iter;
1317 return 0;
1318}
1319
1320static struct file_operations netlink_seq_fops = {
1321 .owner = THIS_MODULE,
1322 .open = netlink_seq_open,
1323 .read = seq_read,
1324 .llseek = seq_lseek,
1325 .release = seq_release_private,
1326};
1327
1328#endif
1329
1330int netlink_register_notifier(struct notifier_block *nb)
1331{
1332 return notifier_chain_register(&netlink_chain, nb);
1333}
1334
1335int netlink_unregister_notifier(struct notifier_block *nb)
1336{
1337 return notifier_chain_unregister(&netlink_chain, nb);
1338}
1339
1340static struct proto_ops netlink_ops = {
1341 .family = PF_NETLINK,
1342 .owner = THIS_MODULE,
1343 .release = netlink_release,
1344 .bind = netlink_bind,
1345 .connect = netlink_connect,
1346 .socketpair = sock_no_socketpair,
1347 .accept = sock_no_accept,
1348 .getname = netlink_getname,
1349 .poll = datagram_poll,
1350 .ioctl = sock_no_ioctl,
1351 .listen = sock_no_listen,
1352 .shutdown = sock_no_shutdown,
1353 .setsockopt = sock_no_setsockopt,
1354 .getsockopt = sock_no_getsockopt,
1355 .sendmsg = netlink_sendmsg,
1356 .recvmsg = netlink_recvmsg,
1357 .mmap = sock_no_mmap,
1358 .sendpage = sock_no_sendpage,
1359};
1360
1361static struct net_proto_family netlink_family_ops = {
1362 .family = PF_NETLINK,
1363 .create = netlink_create,
1364 .owner = THIS_MODULE, /* for consistency 8) */
1365};
1366
1367extern void netlink_skb_parms_too_large(void);
1368
1369static int __init netlink_proto_init(void)
1370{
1371 struct sk_buff *dummy_skb;
1372 int i;
1373 unsigned long max;
1374 unsigned int order;
1375 int err = proto_register(&netlink_proto, 0);
1376
1377 if (err != 0)
1378 goto out;
1379
1380 if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb))
1381 netlink_skb_parms_too_large();
1382
1383 nl_table = kmalloc(sizeof(*nl_table) * MAX_LINKS, GFP_KERNEL);
1384 if (!nl_table) {
1385enomem:
1386 printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n");
1387 return -ENOMEM;
1388 }
1389
1390 memset(nl_table, 0, sizeof(*nl_table) * MAX_LINKS);
1391
1392 if (num_physpages >= (128 * 1024))
1393 max = num_physpages >> (21 - PAGE_SHIFT);
1394 else
1395 max = num_physpages >> (23 - PAGE_SHIFT);
1396
1397 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1398 max = (1UL << order) / sizeof(struct hlist_head);
1399 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1400
1401 for (i = 0; i < MAX_LINKS; i++) {
1402 struct nl_pid_hash *hash = &nl_table[i].hash;
1403
1404 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1405 if (!hash->table) {
1406 while (i-- > 0)
1407 nl_pid_hash_free(nl_table[i].hash.table,
1408 1 * sizeof(*hash->table));
1409 kfree(nl_table);
1410 goto enomem;
1411 }
1412 memset(hash->table, 0, 1 * sizeof(*hash->table));
1413 hash->max_shift = order;
1414 hash->shift = 0;
1415 hash->mask = 0;
1416 hash->rehash_time = jiffies;
1417 }
1418
1419 sock_register(&netlink_family_ops);
1420#ifdef CONFIG_PROC_FS
1421 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1422#endif
1423 /* The netlink device handler may be needed early. */
1424 rtnetlink_init();
1425out:
1426 return err;
1427}
1428
1429static void __exit netlink_proto_exit(void)
1430{
1431 sock_unregister(PF_NETLINK);
1432 proc_net_remove("netlink");
1433 kfree(nl_table);
1434 nl_table = NULL;
1435 proto_unregister(&netlink_proto);
1436}
1437
1438core_initcall(netlink_proto_init);
1439module_exit(netlink_proto_exit);
1440
1441MODULE_LICENSE("GPL");
1442
1443MODULE_ALIAS_NETPROTO(PF_NETLINK);
1444
1445EXPORT_SYMBOL(netlink_ack);
1446EXPORT_SYMBOL(netlink_broadcast);
1447EXPORT_SYMBOL(netlink_dump_start);
1448EXPORT_SYMBOL(netlink_kernel_create);
1449EXPORT_SYMBOL(netlink_register_notifier);
1450EXPORT_SYMBOL(netlink_set_err);
1451EXPORT_SYMBOL(netlink_set_nonroot);
1452EXPORT_SYMBOL(netlink_unicast);
1453EXPORT_SYMBOL(netlink_unregister_notifier);
1454
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-24 23:11:50 -0500