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