2 * scsi_netlink.c - SCSI Transport Netlink Interface
4 * Copyright (C) 2006 James Smart, Emulex Corporation
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.
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.
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
21 #include <linux/time.h>
22 #include <linux/jiffies.h>
23 #include <linux/security.h>
24 #include <linux/delay.h>
26 #include <net/netlink.h>
28 #include <scsi/scsi_netlink.h>
29 #include "scsi_priv.h"
31 struct sock *scsi_nl_sock = NULL;
32 EXPORT_SYMBOL_GPL(scsi_nl_sock);
34 static DEFINE_SPINLOCK(scsi_nl_lock);
35 static struct list_head scsi_nl_drivers;
37 static u32 scsi_nl_state;
38 #define STATE_EHANDLER_BSY 0x00000001
40 struct scsi_nl_transport {
41 int (*msg_handler)(struct sk_buff *);
42 void (*event_handler)(struct notifier_block *, unsigned long, void *);
47 /* flags values (bit flags) */
48 #define HANDLER_DELETING 0x1
50 static struct scsi_nl_transport transports[SCSI_NL_MAX_TRANSPORTS] =
55 struct list_head next;
56 int (*dmsg_handler)(struct Scsi_Host *shost, void *payload,
58 void (*devt_handler)(struct notifier_block *nb,
59 unsigned long event, void *notify_ptr);
60 struct scsi_host_template *hostt;
69 * scsi_nl_rcv_msg - Receive message handler.
70 * @skb: socket receive buffer
72 * Description: Extracts message from a receive buffer.
73 * Validates message header and calls appropriate transport message handler
78 scsi_nl_rcv_msg(struct sk_buff *skb)
81 struct scsi_nl_hdr *hdr;
86 while (skb->len >= NLMSG_SPACE(0)) {
90 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
91 (skb->len < nlh->nlmsg_len)) {
92 printk(KERN_WARNING "%s: discarding partial skb\n",
97 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
101 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
106 hdr = NLMSG_DATA(nlh);
107 if ((hdr->version != SCSI_NL_VERSION) ||
108 (hdr->magic != SCSI_NL_MAGIC)) {
113 if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
118 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
119 printk(KERN_WARNING "%s: discarding partial message\n",
125 * Deliver message to the appropriate transport
127 spin_lock_irqsave(&scsi_nl_lock, flags);
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--;
141 spin_unlock_irqrestore(&scsi_nl_lock, flags);
144 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
145 netlink_ack(skb, nlh, err);
153 * scsi_nl_rcv_event - Event handler for a netlink socket.
154 * @this: event notifier block
156 * @ptr: event payload
160 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
162 struct netlink_notify *n = ptr;
163 struct scsi_nl_drvr *driver;
167 if (n->protocol != NETLINK_SCSITRANSPORT)
170 spin_lock_irqsave(&scsi_nl_lock, flags);
171 scsi_nl_state |= STATE_EHANDLER_BSY;
174 * Pass event on to any transports that may be listening
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);
186 * Pass event on to any drivers that may be listening
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);
197 scsi_nl_state &= ~STATE_EHANDLER_BSY;
198 spin_unlock_irqrestore(&scsi_nl_lock, flags);
203 static struct notifier_block scsi_netlink_notifier = {
204 .notifier_call = scsi_nl_rcv_event,
209 * GENERIC SCSI transport receive and event handlers
213 * scsi_generic_msg_handler - receive message handler for GENERIC transport messages
214 * @skb: socket receive buffer
217 scsi_generic_msg_handler(struct sk_buff *skb)
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;
224 int err = 0, match, pid;
226 pid = NETLINK_CREDS(skb)->pid;
228 switch (snlh->msgtype) {
229 case SCSI_NL_SHOST_VENDOR:
231 struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
233 /* Locate the driver that corresponds to the message */
234 spin_lock_irqsave(&scsi_nl_lock, flags);
236 list_for_each_entry(driver, &scsi_nl_drivers, next) {
237 if (driver->vendor_id == msg->vendor_id) {
243 if ((!match) || (!driver->dmsg_handler)) {
244 spin_unlock_irqrestore(&scsi_nl_lock, flags);
249 if (driver->flags & HANDLER_DELETING) {
250 spin_unlock_irqrestore(&scsi_nl_lock, flags);
256 spin_unlock_irqrestore(&scsi_nl_lock, flags);
259 /* if successful, scsi_host_lookup takes a shost reference */
260 shost = scsi_host_lookup(msg->host_no);
266 /* is this host owned by the vendor ? */
267 if (shost->hostt != driver->hostt) {
272 /* pass message on to the driver */
273 err = driver->dmsg_handler(shost, (void *)&msg[1],
274 msg->vmsg_datalen, pid);
277 /* release reference by scsi_host_lookup */
278 scsi_host_put(shost);
281 /* release our own reference on the registration object */
282 spin_lock_irqsave(&scsi_nl_lock, flags);
284 spin_unlock_irqrestore(&scsi_nl_lock, flags);
295 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
296 __func__, snlh->msgtype, err);
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.
306 * @tport: transport registering handlers
307 * @msg_handler: receive message handler callback
308 * @event_handler: receive event handler callback
311 scsi_nl_add_transport(u8 tport,
312 int (*msg_handler)(struct sk_buff *),
313 void (*event_handler)(struct notifier_block *, unsigned long, void *))
318 if (tport >= SCSI_NL_MAX_TRANSPORTS)
321 spin_lock_irqsave(&scsi_nl_lock, flags);
323 if (scsi_nl_state & STATE_EHANDLER_BSY) {
324 spin_unlock_irqrestore(&scsi_nl_lock, flags);
326 spin_lock_irqsave(&scsi_nl_lock, flags);
329 if (transports[tport].msg_handler || transports[tport].event_handler) {
334 transports[tport].msg_handler = msg_handler;
335 transports[tport].event_handler = event_handler;
336 transports[tport].flags = 0;
337 transports[tport].refcnt = 0;
340 spin_unlock_irqrestore(&scsi_nl_lock, flags);
344 EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
348 * scsi_nl_remove_transport -
349 * Disable transport receiption of messages and events
351 * @tport: transport deregistering handlers
355 scsi_nl_remove_transport(u8 tport)
359 spin_lock_irqsave(&scsi_nl_lock, flags);
360 if (scsi_nl_state & STATE_EHANDLER_BSY) {
361 spin_unlock_irqrestore(&scsi_nl_lock, flags);
363 spin_lock_irqsave(&scsi_nl_lock, flags);
366 if (tport < SCSI_NL_MAX_TRANSPORTS) {
367 transports[tport].flags |= HANDLER_DELETING;
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);
374 transports[tport].msg_handler = NULL;
375 transports[tport].event_handler = NULL;
376 transports[tport].flags = 0;
379 spin_unlock_irqrestore(&scsi_nl_lock, flags);
383 EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
387 * scsi_nl_add_driver -
388 * A driver is registering its interfaces for SCSI netlink messages
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
398 * error result otherwise
401 scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
402 int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
404 void (*nlevt_handler)(struct notifier_block *nb,
405 unsigned long event, void *notify_ptr))
407 struct scsi_nl_drvr *driver;
410 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
411 if (unlikely(!driver)) {
412 printk(KERN_ERR "%s: allocation failure\n", __func__);
416 driver->dmsg_handler = nlmsg_handler;
417 driver->devt_handler = nlevt_handler;
418 driver->hostt = hostt;
419 driver->vendor_id = vendor_id;
421 spin_lock_irqsave(&scsi_nl_lock, flags);
422 if (scsi_nl_state & STATE_EHANDLER_BSY) {
423 spin_unlock_irqrestore(&scsi_nl_lock, flags);
425 spin_lock_irqsave(&scsi_nl_lock, flags);
427 list_add_tail(&driver->next, &scsi_nl_drivers);
428 spin_unlock_irqrestore(&scsi_nl_lock, flags);
432 EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
436 * scsi_nl_remove_driver -
437 * An driver is unregistering with the SCSI netlink messages
439 * @vendor_id: The unique identification value for the driver.
442 scsi_nl_remove_driver(u64 vendor_id)
444 struct scsi_nl_drvr *driver;
447 spin_lock_irqsave(&scsi_nl_lock, flags);
448 if (scsi_nl_state & STATE_EHANDLER_BSY) {
449 spin_unlock_irqrestore(&scsi_nl_lock, flags);
451 spin_lock_irqsave(&scsi_nl_lock, flags);
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);
462 list_del(&driver->next);
464 spin_unlock_irqrestore(&scsi_nl_lock, flags);
469 spin_unlock_irqrestore(&scsi_nl_lock, flags);
471 printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
472 __func__, (unsigned long long)vendor_id);
475 EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
479 * scsi_netlink_init - Called by SCSI subsystem to intialize
480 * the SCSI transport netlink interface
484 scsi_netlink_init(void)
488 INIT_LIST_HEAD(&scsi_nl_drivers);
490 error = netlink_register_notifier(&scsi_netlink_notifier);
492 printk(KERN_ERR "%s: register of event handler failed - %d\n",
497 scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
498 SCSI_NL_GRP_CNT, scsi_nl_rcv_msg, NULL,
501 printk(KERN_ERR "%s: register of recieve handler failed\n",
503 netlink_unregister_notifier(&scsi_netlink_notifier);
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);
511 printk(KERN_ERR "%s: register of GENERIC transport handler"
512 " failed - %d\n", __func__, error);
518 * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
522 scsi_netlink_exit(void)
524 scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
527 netlink_kernel_release(scsi_nl_sock);
528 netlink_unregister_notifier(&scsi_netlink_notifier);
536 * Exported Interfaces
540 * scsi_nl_send_transport_msg -
541 * Generic function to send a single message from a SCSI transport to
544 * @pid: receiving pid
545 * @hdr: message payload
549 scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
552 struct nlmsghdr *nlh;
560 fn = "netlink socket";
564 len = NLMSG_SPACE(hdr->msglen);
565 skblen = NLMSG_SPACE(len);
567 skb = alloc_skb(skblen, GFP_KERNEL);
574 nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
580 datab = NLMSG_DATA(nlh);
581 memcpy(datab, hdr, hdr->msglen);
583 err = nlmsg_unicast(scsi_nl_sock, skb, pid);
585 fn = "nlmsg_unicast";
586 /* nlmsg_unicast already kfree_skb'd */
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,
602 EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
606 * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
607 * to a specific process id.
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
616 * 0 on succesful return
617 * otherwise, failing error code
620 * This routine assumes no locks are held on entry.
623 scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
624 char *data_buf, u32 data_len)
627 struct nlmsghdr *nlh;
628 struct scsi_nl_host_vendor_msg *msg;
634 goto send_vendor_fail;
637 len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
638 skblen = NLMSG_SPACE(len);
640 skb = alloc_skb(skblen, GFP_KERNEL);
643 goto send_vendor_fail;
646 nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
647 skblen - sizeof(*nlh), 0);
650 goto send_vendor_fail_skb;
652 msg = NLMSG_DATA(nlh);
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);
661 err = nlmsg_unicast(scsi_nl_sock, skb, pid);
663 /* nlmsg_multicast already kfree_skb'd */
664 goto send_vendor_fail;
668 send_vendor_fail_skb:
672 "%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
673 __func__, host_no, err);
676 EXPORT_SYMBOL(scsi_nl_send_vendor_msg);