tree-wide: fix assorted typos all over the place
[linux-2.6.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 messages
214  * @skb:                socket receive buffer
215  **/
216 static int
217 scsi_generic_msg_handler(struct sk_buff *skb)
218 {
219         struct nlmsghdr *nlh = nlmsg_hdr(skb);
220         struct scsi_nl_hdr *snlh = NLMSG_DATA(nlh);
221         struct scsi_nl_drvr *driver;
222         struct Scsi_Host *shost;
223         unsigned long flags;
224         int err = 0, match, pid;
225
226         pid = NETLINK_CREDS(skb)->pid;
227
228         switch (snlh->msgtype) {
229         case SCSI_NL_SHOST_VENDOR:
230                 {
231                 struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
232
233                 /* Locate the driver that corresponds to the message */
234                 spin_lock_irqsave(&scsi_nl_lock, flags);
235                 match = 0;
236                 list_for_each_entry(driver, &scsi_nl_drivers, next) {
237                         if (driver->vendor_id == msg->vendor_id) {
238                                 match = 1;
239                                 break;
240                         }
241                 }
242
243                 if ((!match) || (!driver->dmsg_handler)) {
244                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
245                         err = -ESRCH;
246                         goto rcv_exit;
247                 }
248
249                 if (driver->flags & HANDLER_DELETING) {
250                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
251                         err = -ESHUTDOWN;
252                         goto rcv_exit;
253                 }
254
255                 driver->refcnt++;
256                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
257
258
259                 /* if successful, scsi_host_lookup takes a shost reference */
260                 shost = scsi_host_lookup(msg->host_no);
261                 if (!shost) {
262                         err = -ENODEV;
263                         goto driver_exit;
264                 }
265
266                 /* is this host owned by the vendor ? */
267                 if (shost->hostt != driver->hostt) {
268                         err = -EINVAL;
269                         goto vendormsg_put;
270                 }
271
272                 /* pass message on to the driver */
273                 err = driver->dmsg_handler(shost, (void *)&msg[1],
274                                          msg->vmsg_datalen, pid);
275
276 vendormsg_put:
277                 /* release reference by scsi_host_lookup */
278                 scsi_host_put(shost);
279
280 driver_exit:
281                 /* release our own reference on the registration object */
282                 spin_lock_irqsave(&scsi_nl_lock, flags);
283                 driver->refcnt--;
284                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
285                 break;
286                 }
287
288         default:
289                 err = -EBADR;
290                 break;
291         }
292
293 rcv_exit:
294         if (err)
295                 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
296                          __func__, snlh->msgtype, err);
297         return err;
298 }
299
300
301 /**
302  * scsi_nl_add_transport -
303  *    Registers message and event handlers for a transport. Enables
304  *    receipt of netlink messages and events to a transport.
305  *
306  * @tport:              transport registering handlers
307  * @msg_handler:        receive message handler callback
308  * @event_handler:      receive event handler callback
309  **/
310 int
311 scsi_nl_add_transport(u8 tport,
312         int (*msg_handler)(struct sk_buff *),
313         void (*event_handler)(struct notifier_block *, unsigned long, void *))
314 {
315         unsigned long flags;
316         int err = 0;
317
318         if (tport >= SCSI_NL_MAX_TRANSPORTS)
319                 return -EINVAL;
320
321         spin_lock_irqsave(&scsi_nl_lock, flags);
322
323         if (scsi_nl_state & STATE_EHANDLER_BSY) {
324                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
325                 msleep(1);
326                 spin_lock_irqsave(&scsi_nl_lock, flags);
327         }
328
329         if (transports[tport].msg_handler || transports[tport].event_handler) {
330                 err = -EALREADY;
331                 goto register_out;
332         }
333
334         transports[tport].msg_handler = msg_handler;
335         transports[tport].event_handler = event_handler;
336         transports[tport].flags = 0;
337         transports[tport].refcnt = 0;
338
339 register_out:
340         spin_unlock_irqrestore(&scsi_nl_lock, flags);
341
342         return err;
343 }
344 EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
345
346
347 /**
348  * scsi_nl_remove_transport -
349  *    Disable transport receiption of messages and events
350  *
351  * @tport:              transport deregistering handlers
352  *
353  **/
354 void
355 scsi_nl_remove_transport(u8 tport)
356 {
357         unsigned long flags;
358
359         spin_lock_irqsave(&scsi_nl_lock, flags);
360         if (scsi_nl_state & STATE_EHANDLER_BSY) {
361                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
362                 msleep(1);
363                 spin_lock_irqsave(&scsi_nl_lock, flags);
364         }
365
366         if (tport < SCSI_NL_MAX_TRANSPORTS) {
367                 transports[tport].flags |= HANDLER_DELETING;
368
369                 while (transports[tport].refcnt != 0) {
370                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
371                         schedule_timeout_uninterruptible(HZ/4);
372                         spin_lock_irqsave(&scsi_nl_lock, flags);
373                 }
374                 transports[tport].msg_handler = NULL;
375                 transports[tport].event_handler = NULL;
376                 transports[tport].flags = 0;
377         }
378
379         spin_unlock_irqrestore(&scsi_nl_lock, flags);
380
381         return;
382 }
383 EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
384
385
386 /**
387  * scsi_nl_add_driver -
388  *    A driver is registering its interfaces for SCSI netlink messages
389  *
390  * @vendor_id:          A unique identification value for the driver.
391  * @hostt:              address of the driver's host template. Used
392  *                      to verify an shost is bound to the driver
393  * @nlmsg_handler:      receive message handler callback
394  * @nlevt_handler:      receive event handler callback
395  *
396  * Returns:
397  *   0 on Success
398  *   error result otherwise
399  **/
400 int
401 scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
402         int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
403                                  u32 len, u32 pid),
404         void (*nlevt_handler)(struct notifier_block *nb,
405                                  unsigned long event, void *notify_ptr))
406 {
407         struct scsi_nl_drvr *driver;
408         unsigned long flags;
409
410         driver = kzalloc(sizeof(*driver), GFP_KERNEL);
411         if (unlikely(!driver)) {
412                 printk(KERN_ERR "%s: allocation failure\n", __func__);
413                 return -ENOMEM;
414         }
415
416         driver->dmsg_handler = nlmsg_handler;
417         driver->devt_handler = nlevt_handler;
418         driver->hostt = hostt;
419         driver->vendor_id = vendor_id;
420
421         spin_lock_irqsave(&scsi_nl_lock, flags);
422         if (scsi_nl_state & STATE_EHANDLER_BSY) {
423                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
424                 msleep(1);
425                 spin_lock_irqsave(&scsi_nl_lock, flags);
426         }
427         list_add_tail(&driver->next, &scsi_nl_drivers);
428         spin_unlock_irqrestore(&scsi_nl_lock, flags);
429
430         return 0;
431 }
432 EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
433
434
435 /**
436  * scsi_nl_remove_driver -
437  *    An driver is unregistering with the SCSI netlink messages
438  *
439  * @vendor_id:          The unique identification value for the driver.
440  **/
441 void
442 scsi_nl_remove_driver(u64 vendor_id)
443 {
444         struct scsi_nl_drvr *driver;
445         unsigned long flags;
446
447         spin_lock_irqsave(&scsi_nl_lock, flags);
448         if (scsi_nl_state & STATE_EHANDLER_BSY) {
449                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
450                 msleep(1);
451                 spin_lock_irqsave(&scsi_nl_lock, flags);
452         }
453
454         list_for_each_entry(driver, &scsi_nl_drivers, next) {
455                 if (driver->vendor_id == vendor_id) {
456                         driver->flags |= HANDLER_DELETING;
457                         while (driver->refcnt != 0) {
458                                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
459                                 schedule_timeout_uninterruptible(HZ/4);
460                                 spin_lock_irqsave(&scsi_nl_lock, flags);
461                         }
462                         list_del(&driver->next);
463                         kfree(driver);
464                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
465                         return;
466                 }
467         }
468
469         spin_unlock_irqrestore(&scsi_nl_lock, flags);
470
471         printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
472                __func__, (unsigned long long)vendor_id);
473         return;
474 }
475 EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
476
477
478 /**
479  * scsi_netlink_init - Called by SCSI subsystem to intialize
480  *      the SCSI transport netlink interface
481  *
482  **/
483 void
484 scsi_netlink_init(void)
485 {
486         int error;
487
488         INIT_LIST_HEAD(&scsi_nl_drivers);
489
490         error = netlink_register_notifier(&scsi_netlink_notifier);
491         if (error) {
492                 printk(KERN_ERR "%s: register of event handler failed - %d\n",
493                                 __func__, error);
494                 return;
495         }
496
497         scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
498                                 SCSI_NL_GRP_CNT, scsi_nl_rcv_msg, NULL,
499                                 THIS_MODULE);
500         if (!scsi_nl_sock) {
501                 printk(KERN_ERR "%s: register of recieve handler failed\n",
502                                 __func__);
503                 netlink_unregister_notifier(&scsi_netlink_notifier);
504                 return;
505         }
506
507         /* Register the entry points for the generic SCSI transport */
508         error = scsi_nl_add_transport(SCSI_NL_TRANSPORT,
509                                 scsi_generic_msg_handler, NULL);
510         if (error)
511                 printk(KERN_ERR "%s: register of GENERIC transport handler"
512                                 "  failed - %d\n", __func__, error);
513         return;
514 }
515
516
517 /**
518  * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
519  *
520  **/
521 void
522 scsi_netlink_exit(void)
523 {
524         scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
525
526         if (scsi_nl_sock) {
527                 netlink_kernel_release(scsi_nl_sock);
528                 netlink_unregister_notifier(&scsi_netlink_notifier);
529         }
530
531         return;
532 }
533
534
535 /*
536  * Exported Interfaces
537  */
538
539 /**
540  * scsi_nl_send_transport_msg -
541  *    Generic function to send a single message from a SCSI transport to
542  *    a single process
543  *
544  * @pid:                receiving pid
545  * @hdr:                message payload
546  *
547  **/
548 void
549 scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
550 {
551         struct sk_buff *skb;
552         struct nlmsghdr *nlh;
553         const char *fn;
554         char *datab;
555         u32 len, skblen;
556         int err;
557
558         if (!scsi_nl_sock) {
559                 err = -ENOENT;
560                 fn = "netlink socket";
561                 goto msg_fail;
562         }
563
564         len = NLMSG_SPACE(hdr->msglen);
565         skblen = NLMSG_SPACE(len);
566
567         skb = alloc_skb(skblen, GFP_KERNEL);
568         if (!skb) {
569                 err = -ENOBUFS;
570                 fn = "alloc_skb";
571                 goto msg_fail;
572         }
573
574         nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
575         if (!nlh) {
576                 err = -ENOBUFS;
577                 fn = "nlmsg_put";
578                 goto msg_fail_skb;
579         }
580         datab = NLMSG_DATA(nlh);
581         memcpy(datab, hdr, hdr->msglen);
582
583         err = nlmsg_unicast(scsi_nl_sock, skb, pid);
584         if (err < 0) {
585                 fn = "nlmsg_unicast";
586                 /* nlmsg_unicast already kfree_skb'd */
587                 goto msg_fail;
588         }
589
590         return;
591
592 msg_fail_skb:
593         kfree_skb(skb);
594 msg_fail:
595         printk(KERN_WARNING
596                 "%s: Dropped Message : pid %d Transport %d, msgtype x%x, "
597                 "msglen %d: %s : err %d\n",
598                 __func__, pid, hdr->transport, hdr->msgtype, hdr->msglen,
599                 fn, err);
600         return;
601 }
602 EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
603
604
605 /**
606  * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
607  *                      to a specific process id.
608  *
609  * @pid:                process id of the receiver
610  * @host_no:            host # sending the message
611  * @vendor_id:          unique identifier for the driver's vendor
612  * @data_len:           amount, in bytes, of vendor unique payload data
613  * @data_buf:           pointer to vendor unique data buffer
614  *
615  * Returns:
616  *   0 on successful return
617  *   otherwise, failing error code
618  *
619  * Notes:
620  *      This routine assumes no locks are held on entry.
621  */
622 int
623 scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
624                          char *data_buf, u32 data_len)
625 {
626         struct sk_buff *skb;
627         struct nlmsghdr *nlh;
628         struct scsi_nl_host_vendor_msg *msg;
629         u32 len, skblen;
630         int err;
631
632         if (!scsi_nl_sock) {
633                 err = -ENOENT;
634                 goto send_vendor_fail;
635         }
636
637         len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
638         skblen = NLMSG_SPACE(len);
639
640         skb = alloc_skb(skblen, GFP_KERNEL);
641         if (!skb) {
642                 err = -ENOBUFS;
643                 goto send_vendor_fail;
644         }
645
646         nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
647                                 skblen - sizeof(*nlh), 0);
648         if (!nlh) {
649                 err = -ENOBUFS;
650                 goto send_vendor_fail_skb;
651         }
652         msg = NLMSG_DATA(nlh);
653
654         INIT_SCSI_NL_HDR(&msg->snlh, SCSI_NL_TRANSPORT,
655                                 SCSI_NL_SHOST_VENDOR, len);
656         msg->vendor_id = vendor_id;
657         msg->host_no = host_no;
658         msg->vmsg_datalen = data_len;   /* bytes */
659         memcpy(&msg[1], data_buf, data_len);
660
661         err = nlmsg_unicast(scsi_nl_sock, skb, pid);
662         if (err)
663                 /* nlmsg_multicast already kfree_skb'd */
664                 goto send_vendor_fail;
665
666         return 0;
667
668 send_vendor_fail_skb:
669         kfree_skb(skb);
670 send_vendor_fail:
671         printk(KERN_WARNING
672                 "%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
673                 __func__, host_no, err);
674         return err;
675 }
676 EXPORT_SYMBOL(scsi_nl_send_vendor_msg);
677
678