Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6
[deliverable/linux.git] / drivers / scsi / scsi_netlink.c
1 /*
2 * scsi_netlink.c - SCSI Transport Netlink Interface
3 *
4 * Copyright (C) 2006 James Smart, Emulex Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21 #include <linux/time.h>
22 #include <linux/jiffies.h>
23 #include <linux/security.h>
24 #include <linux/delay.h>
25 #include <net/sock.h>
26 #include <net/netlink.h>
27
28 #include <scsi/scsi_netlink.h>
29 #include "scsi_priv.h"
30
31 struct sock *scsi_nl_sock = NULL;
32 EXPORT_SYMBOL_GPL(scsi_nl_sock);
33
34 static DEFINE_SPINLOCK(scsi_nl_lock);
35 static struct list_head scsi_nl_drivers;
36
37 static u32 scsi_nl_state;
38 #define STATE_EHANDLER_BSY 0x00000001
39
40 struct scsi_nl_transport {
41 int (*msg_handler)(struct sk_buff *);
42 void (*event_handler)(struct notifier_block *, unsigned long, void *);
43 unsigned int refcnt;
44 int flags;
45 };
46
47 /* flags values (bit flags) */
48 #define HANDLER_DELETING 0x1
49
50 static struct scsi_nl_transport transports[SCSI_NL_MAX_TRANSPORTS] =
51 { {NULL, }, };
52
53
54 struct scsi_nl_drvr {
55 struct list_head next;
56 int (*dmsg_handler)(struct Scsi_Host *shost, void *payload,
57 u32 len, u32 pid);
58 void (*devt_handler)(struct notifier_block *nb,
59 unsigned long event, void *notify_ptr);
60 struct scsi_host_template *hostt;
61 u64 vendor_id;
62 unsigned int refcnt;
63 int flags;
64 };
65
66
67
68 /**
69 * scsi_nl_rcv_msg - Receive message handler.
70 * @skb: socket receive buffer
71 *
72 * Description: Extracts message from a receive buffer.
73 * Validates message header and calls appropriate transport message handler
74 *
75 *
76 **/
77 static void
78 scsi_nl_rcv_msg(struct sk_buff *skb)
79 {
80 struct nlmsghdr *nlh;
81 struct scsi_nl_hdr *hdr;
82 unsigned long flags;
83 u32 rlen;
84 int err, tport;
85
86 while (skb->len >= NLMSG_SPACE(0)) {
87 err = 0;
88
89 nlh = nlmsg_hdr(skb);
90 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
91 (skb->len < nlh->nlmsg_len)) {
92 printk(KERN_WARNING "%s: discarding partial skb\n",
93 __func__);
94 return;
95 }
96
97 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
98 if (rlen > skb->len)
99 rlen = skb->len;
100
101 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
102 err = -EBADMSG;
103 goto next_msg;
104 }
105
106 hdr = NLMSG_DATA(nlh);
107 if ((hdr->version != SCSI_NL_VERSION) ||
108 (hdr->magic != SCSI_NL_MAGIC)) {
109 err = -EPROTOTYPE;
110 goto next_msg;
111 }
112
113 if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
114 err = -EPERM;
115 goto next_msg;
116 }
117
118 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
119 printk(KERN_WARNING "%s: discarding partial message\n",
120 __func__);
121 goto next_msg;
122 }
123
124 /*
125 * Deliver message to the appropriate transport
126 */
127 spin_lock_irqsave(&scsi_nl_lock, flags);
128
129 tport = hdr->transport;
130 if ((tport < SCSI_NL_MAX_TRANSPORTS) &&
131 !(transports[tport].flags & HANDLER_DELETING) &&
132 (transports[tport].msg_handler)) {
133 transports[tport].refcnt++;
134 spin_unlock_irqrestore(&scsi_nl_lock, flags);
135 err = transports[tport].msg_handler(skb);
136 spin_lock_irqsave(&scsi_nl_lock, flags);
137 transports[tport].refcnt--;
138 } else
139 err = -ENOENT;
140
141 spin_unlock_irqrestore(&scsi_nl_lock, flags);
142
143 next_msg:
144 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
145 netlink_ack(skb, nlh, err);
146
147 skb_pull(skb, rlen);
148 }
149 }
150
151
152 /**
153 * scsi_nl_rcv_event - Event handler for a netlink socket.
154 * @this: event notifier block
155 * @event: event type
156 * @ptr: event payload
157 *
158 **/
159 static int
160 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
161 {
162 struct netlink_notify *n = ptr;
163 struct scsi_nl_drvr *driver;
164 unsigned long flags;
165 int tport;
166
167 if (n->protocol != NETLINK_SCSITRANSPORT)
168 return NOTIFY_DONE;
169
170 spin_lock_irqsave(&scsi_nl_lock, flags);
171 scsi_nl_state |= STATE_EHANDLER_BSY;
172
173 /*
174 * Pass event on to any transports that may be listening
175 */
176 for (tport = 0; tport < SCSI_NL_MAX_TRANSPORTS; tport++) {
177 if (!(transports[tport].flags & HANDLER_DELETING) &&
178 (transports[tport].event_handler)) {
179 spin_unlock_irqrestore(&scsi_nl_lock, flags);
180 transports[tport].event_handler(this, event, ptr);
181 spin_lock_irqsave(&scsi_nl_lock, flags);
182 }
183 }
184
185 /*
186 * Pass event on to any drivers that may be listening
187 */
188 list_for_each_entry(driver, &scsi_nl_drivers, next) {
189 if (!(driver->flags & HANDLER_DELETING) &&
190 (driver->devt_handler)) {
191 spin_unlock_irqrestore(&scsi_nl_lock, flags);
192 driver->devt_handler(this, event, ptr);
193 spin_lock_irqsave(&scsi_nl_lock, flags);
194 }
195 }
196
197 scsi_nl_state &= ~STATE_EHANDLER_BSY;
198 spin_unlock_irqrestore(&scsi_nl_lock, flags);
199
200 return NOTIFY_DONE;
201 }
202
203 static struct notifier_block scsi_netlink_notifier = {
204 .notifier_call = scsi_nl_rcv_event,
205 };
206
207
208 /**
209 * GENERIC SCSI transport receive and event handlers
210 **/
211
212 /**
213 * scsi_generic_msg_handler - receive message handler for GENERIC transport
214 * messages
215 *
216 * @skb: socket receive buffer
217 *
218 **/
219 static int
220 scsi_generic_msg_handler(struct sk_buff *skb)
221 {
222 struct nlmsghdr *nlh = nlmsg_hdr(skb);
223 struct scsi_nl_hdr *snlh = NLMSG_DATA(nlh);
224 struct scsi_nl_drvr *driver;
225 struct Scsi_Host *shost;
226 unsigned long flags;
227 int err = 0, match, pid;
228
229 pid = NETLINK_CREDS(skb)->pid;
230
231 switch (snlh->msgtype) {
232 case SCSI_NL_SHOST_VENDOR:
233 {
234 struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
235
236 /* Locate the driver that corresponds to the message */
237 spin_lock_irqsave(&scsi_nl_lock, flags);
238 match = 0;
239 list_for_each_entry(driver, &scsi_nl_drivers, next) {
240 if (driver->vendor_id == msg->vendor_id) {
241 match = 1;
242 break;
243 }
244 }
245
246 if ((!match) || (!driver->dmsg_handler)) {
247 spin_unlock_irqrestore(&scsi_nl_lock, flags);
248 err = -ESRCH;
249 goto rcv_exit;
250 }
251
252 if (driver->flags & HANDLER_DELETING) {
253 spin_unlock_irqrestore(&scsi_nl_lock, flags);
254 err = -ESHUTDOWN;
255 goto rcv_exit;
256 }
257
258 driver->refcnt++;
259 spin_unlock_irqrestore(&scsi_nl_lock, flags);
260
261
262 /* if successful, scsi_host_lookup takes a shost reference */
263 shost = scsi_host_lookup(msg->host_no);
264 if (!shost) {
265 err = -ENODEV;
266 goto driver_exit;
267 }
268
269 /* is this host owned by the vendor ? */
270 if (shost->hostt != driver->hostt) {
271 err = -EINVAL;
272 goto vendormsg_put;
273 }
274
275 /* pass message on to the driver */
276 err = driver->dmsg_handler(shost, (void *)&msg[1],
277 msg->vmsg_datalen, pid);
278
279 vendormsg_put:
280 /* release reference by scsi_host_lookup */
281 scsi_host_put(shost);
282
283 driver_exit:
284 /* release our own reference on the registration object */
285 spin_lock_irqsave(&scsi_nl_lock, flags);
286 driver->refcnt--;
287 spin_unlock_irqrestore(&scsi_nl_lock, flags);
288 break;
289 }
290
291 default:
292 err = -EBADR;
293 break;
294 }
295
296 rcv_exit:
297 if (err)
298 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
299 __func__, snlh->msgtype, err);
300 return err;
301 }
302
303
304 /**
305 * scsi_nl_add_transport -
306 * Registers message and event handlers for a transport. Enables
307 * receipt of netlink messages and events to a transport.
308 *
309 * @tport: transport registering handlers
310 * @msg_handler: receive message handler callback
311 * @event_handler: receive event handler callback
312 **/
313 int
314 scsi_nl_add_transport(u8 tport,
315 int (*msg_handler)(struct sk_buff *),
316 void (*event_handler)(struct notifier_block *, unsigned long, void *))
317 {
318 unsigned long flags;
319 int err = 0;
320
321 if (tport >= SCSI_NL_MAX_TRANSPORTS)
322 return -EINVAL;
323
324 spin_lock_irqsave(&scsi_nl_lock, flags);
325
326 if (scsi_nl_state & STATE_EHANDLER_BSY) {
327 spin_unlock_irqrestore(&scsi_nl_lock, flags);
328 msleep(1);
329 spin_lock_irqsave(&scsi_nl_lock, flags);
330 }
331
332 if (transports[tport].msg_handler || transports[tport].event_handler) {
333 err = -EALREADY;
334 goto register_out;
335 }
336
337 transports[tport].msg_handler = msg_handler;
338 transports[tport].event_handler = event_handler;
339 transports[tport].flags = 0;
340 transports[tport].refcnt = 0;
341
342 register_out:
343 spin_unlock_irqrestore(&scsi_nl_lock, flags);
344
345 return err;
346 }
347 EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
348
349
350 /**
351 * scsi_nl_remove_transport -
352 * Disable transport receiption of messages and events
353 *
354 * @tport: transport deregistering handlers
355 *
356 **/
357 void
358 scsi_nl_remove_transport(u8 tport)
359 {
360 unsigned long flags;
361
362 spin_lock_irqsave(&scsi_nl_lock, flags);
363 if (scsi_nl_state & STATE_EHANDLER_BSY) {
364 spin_unlock_irqrestore(&scsi_nl_lock, flags);
365 msleep(1);
366 spin_lock_irqsave(&scsi_nl_lock, flags);
367 }
368
369 if (tport < SCSI_NL_MAX_TRANSPORTS) {
370 transports[tport].flags |= HANDLER_DELETING;
371
372 while (transports[tport].refcnt != 0) {
373 spin_unlock_irqrestore(&scsi_nl_lock, flags);
374 schedule_timeout_uninterruptible(HZ/4);
375 spin_lock_irqsave(&scsi_nl_lock, flags);
376 }
377 transports[tport].msg_handler = NULL;
378 transports[tport].event_handler = NULL;
379 transports[tport].flags = 0;
380 }
381
382 spin_unlock_irqrestore(&scsi_nl_lock, flags);
383
384 return;
385 }
386 EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
387
388
389 /**
390 * scsi_nl_add_driver -
391 * A driver is registering its interfaces for SCSI netlink messages
392 *
393 * @vendor_id: A unique identification value for the driver.
394 * @hostt: address of the driver's host template. Used
395 * to verify an shost is bound to the driver
396 * @nlmsg_handler: receive message handler callback
397 * @nlevt_handler: receive event handler callback
398 *
399 * Returns:
400 * 0 on Success
401 * error result otherwise
402 **/
403 int
404 scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
405 int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
406 u32 len, u32 pid),
407 void (*nlevt_handler)(struct notifier_block *nb,
408 unsigned long event, void *notify_ptr))
409 {
410 struct scsi_nl_drvr *driver;
411 unsigned long flags;
412
413 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
414 if (unlikely(!driver)) {
415 printk(KERN_ERR "%s: allocation failure\n", __func__);
416 return -ENOMEM;
417 }
418
419 driver->dmsg_handler = nlmsg_handler;
420 driver->devt_handler = nlevt_handler;
421 driver->hostt = hostt;
422 driver->vendor_id = vendor_id;
423
424 spin_lock_irqsave(&scsi_nl_lock, flags);
425 if (scsi_nl_state & STATE_EHANDLER_BSY) {
426 spin_unlock_irqrestore(&scsi_nl_lock, flags);
427 msleep(1);
428 spin_lock_irqsave(&scsi_nl_lock, flags);
429 }
430 list_add_tail(&driver->next, &scsi_nl_drivers);
431 spin_unlock_irqrestore(&scsi_nl_lock, flags);
432
433 return 0;
434 }
435 EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
436
437
438 /**
439 * scsi_nl_remove_driver -
440 * An driver is unregistering with the SCSI netlink messages
441 *
442 * @vendor_id: The unique identification value for the driver.
443 **/
444 void
445 scsi_nl_remove_driver(u64 vendor_id)
446 {
447 struct scsi_nl_drvr *driver;
448 unsigned long flags;
449
450 spin_lock_irqsave(&scsi_nl_lock, flags);
451 if (scsi_nl_state & STATE_EHANDLER_BSY) {
452 spin_unlock_irqrestore(&scsi_nl_lock, flags);
453 msleep(1);
454 spin_lock_irqsave(&scsi_nl_lock, flags);
455 }
456
457 list_for_each_entry(driver, &scsi_nl_drivers, next) {
458 if (driver->vendor_id == vendor_id) {
459 driver->flags |= HANDLER_DELETING;
460 while (driver->refcnt != 0) {
461 spin_unlock_irqrestore(&scsi_nl_lock, flags);
462 schedule_timeout_uninterruptible(HZ/4);
463 spin_lock_irqsave(&scsi_nl_lock, flags);
464 }
465 list_del(&driver->next);
466 kfree(driver);
467 spin_unlock_irqrestore(&scsi_nl_lock, flags);
468 return;
469 }
470 }
471
472 spin_unlock_irqrestore(&scsi_nl_lock, flags);
473
474 printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
475 __func__, (unsigned long long)vendor_id);
476 return;
477 }
478 EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
479
480
481 /**
482 * scsi_netlink_init - Called by SCSI subsystem to intialize
483 * the SCSI transport netlink interface
484 *
485 **/
486 void
487 scsi_netlink_init(void)
488 {
489 int error;
490
491 INIT_LIST_HEAD(&scsi_nl_drivers);
492
493 error = netlink_register_notifier(&scsi_netlink_notifier);
494 if (error) {
495 printk(KERN_ERR "%s: register of event handler failed - %d\n",
496 __func__, error);
497 return;
498 }
499
500 scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
501 SCSI_NL_GRP_CNT, scsi_nl_rcv_msg, NULL,
502 THIS_MODULE);
503 if (!scsi_nl_sock) {
504 printk(KERN_ERR "%s: register of recieve handler failed\n",
505 __func__);
506 netlink_unregister_notifier(&scsi_netlink_notifier);
507 return;
508 }
509
510 /* Register the entry points for the generic SCSI transport */
511 error = scsi_nl_add_transport(SCSI_NL_TRANSPORT,
512 scsi_generic_msg_handler, NULL);
513 if (error)
514 printk(KERN_ERR "%s: register of GENERIC transport handler"
515 " failed - %d\n", __func__, error);
516 return;
517 }
518
519
520 /**
521 * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
522 *
523 **/
524 void
525 scsi_netlink_exit(void)
526 {
527 scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
528
529 if (scsi_nl_sock) {
530 netlink_kernel_release(scsi_nl_sock);
531 netlink_unregister_notifier(&scsi_netlink_notifier);
532 }
533
534 return;
535 }
536
537
538 /*
539 * Exported Interfaces
540 */
541
542 /**
543 * scsi_nl_send_transport_msg -
544 * Generic function to send a single message from a SCSI transport to
545 * a single process
546 *
547 * @pid: receiving pid
548 * @hdr: message payload
549 *
550 **/
551 void
552 scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
553 {
554 struct sk_buff *skb;
555 struct nlmsghdr *nlh;
556 const char *fn;
557 char *datab;
558 u32 len, skblen;
559 int err;
560
561 if (!scsi_nl_sock) {
562 err = -ENOENT;
563 fn = "netlink socket";
564 goto msg_fail;
565 }
566
567 len = NLMSG_SPACE(hdr->msglen);
568 skblen = NLMSG_SPACE(len);
569
570 skb = alloc_skb(skblen, GFP_KERNEL);
571 if (!skb) {
572 err = -ENOBUFS;
573 fn = "alloc_skb";
574 goto msg_fail;
575 }
576
577 nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
578 if (!nlh) {
579 err = -ENOBUFS;
580 fn = "nlmsg_put";
581 goto msg_fail_skb;
582 }
583 datab = NLMSG_DATA(nlh);
584 memcpy(datab, hdr, hdr->msglen);
585
586 err = nlmsg_unicast(scsi_nl_sock, skb, pid);
587 if (err < 0) {
588 fn = "nlmsg_unicast";
589 /* nlmsg_unicast already kfree_skb'd */
590 goto msg_fail;
591 }
592
593 return;
594
595 msg_fail_skb:
596 kfree_skb(skb);
597 msg_fail:
598 printk(KERN_WARNING
599 "%s: Dropped Message : pid %d Transport %d, msgtype x%x, "
600 "msglen %d: %s : err %d\n",
601 __func__, pid, hdr->transport, hdr->msgtype, hdr->msglen,
602 fn, err);
603 return;
604 }
605 EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
606
607
608 /**
609 * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
610 * to a specific process id.
611 *
612 * @pid: process id of the receiver
613 * @host_no: host # sending the message
614 * @vendor_id: unique identifier for the driver's vendor
615 * @data_len: amount, in bytes, of vendor unique payload data
616 * @data_buf: pointer to vendor unique data buffer
617 *
618 * Returns:
619 * 0 on succesful return
620 * otherwise, failing error code
621 *
622 * Notes:
623 * This routine assumes no locks are held on entry.
624 */
625 int
626 scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
627 char *data_buf, u32 data_len)
628 {
629 struct sk_buff *skb;
630 struct nlmsghdr *nlh;
631 struct scsi_nl_host_vendor_msg *msg;
632 u32 len, skblen;
633 int err;
634
635 if (!scsi_nl_sock) {
636 err = -ENOENT;
637 goto send_vendor_fail;
638 }
639
640 len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
641 skblen = NLMSG_SPACE(len);
642
643 skb = alloc_skb(skblen, GFP_KERNEL);
644 if (!skb) {
645 err = -ENOBUFS;
646 goto send_vendor_fail;
647 }
648
649 nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
650 skblen - sizeof(*nlh), 0);
651 if (!nlh) {
652 err = -ENOBUFS;
653 goto send_vendor_fail_skb;
654 }
655 msg = NLMSG_DATA(nlh);
656
657 INIT_SCSI_NL_HDR(&msg->snlh, SCSI_NL_TRANSPORT,
658 SCSI_NL_SHOST_VENDOR, len);
659 msg->vendor_id = vendor_id;
660 msg->host_no = host_no;
661 msg->vmsg_datalen = data_len; /* bytes */
662 memcpy(&msg[1], data_buf, data_len);
663
664 err = nlmsg_unicast(scsi_nl_sock, skb, pid);
665 if (err)
666 /* nlmsg_multicast already kfree_skb'd */
667 goto send_vendor_fail;
668
669 return 0;
670
671 send_vendor_fail_skb:
672 kfree_skb(skb);
673 send_vendor_fail:
674 printk(KERN_WARNING
675 "%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
676 __func__, host_no, err);
677 return err;
678 }
679 EXPORT_SYMBOL(scsi_nl_send_vendor_msg);
680
681
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