1 files changed, 515 insertions, 8 deletions

diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
index ae7ed9a..b37e133 100644
--- a/drivers/scsi/scsi_netlink.c
+++ b/drivers/scsi/scsi_netlink.c
@@ -21,6 +21,7 @@
 #include <linux/time.h>
 #include <linux/jiffies.h>
 #include <linux/security.h>
+#include <linux/delay.h>
 #include <net/sock.h>
 #include <net/netlink.h>
 
@@ -30,6 +31,39 @@
 struct sock *scsi_nl_sock = NULL;
 EXPORT_SYMBOL_GPL(scsi_nl_sock);
 
+static DEFINE_SPINLOCK(scsi_nl_lock);
+static struct list_head scsi_nl_drivers;
+
+static u32	scsi_nl_state;
+#define STATE_EHANDLER_BSY		0x00000001
+
+struct scsi_nl_transport {
+	int (*msg_handler)(struct sk_buff *);
+	void (*event_handler)(struct notifier_block *, unsigned long, void *);
+	unsigned int refcnt;
+	int flags;
+};
+
+/* flags values (bit flags) */
+#define HANDLER_DELETING		0x1
+
+static struct scsi_nl_transport transports[SCSI_NL_MAX_TRANSPORTS] =
+	{ {NULL, }, };
+
+
+struct scsi_nl_drvr {
+	struct list_head next;
+	int (*dmsg_handler)(struct Scsi_Host *shost, void *payload,
+				 u32 len, u32 pid);
+	void (*devt_handler)(struct notifier_block *nb,
+				 unsigned long event, void *notify_ptr);
+	struct scsi_host_template *hostt;
+	u64 vendor_id;
+	unsigned int refcnt;
+	int flags;
+};
+
+
 
 /**
  * scsi_nl_rcv_msg - Receive message handler.
@@ -45,8 +79,9 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 {
 	struct nlmsghdr *nlh;
 	struct scsi_nl_hdr *hdr;
-	uint32_t rlen;
-	int err;
+	unsigned long flags;
+	u32 rlen;
+	int err, tport;
 
 	while (skb->len >= NLMSG_SPACE(0)) {
 		err = 0;
@@ -65,7 +100,7 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 
 		if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
 			err = -EBADMSG;
-			return;
+			goto next_msg;
 		}
 
 		hdr = NLMSG_DATA(nlh);
@@ -83,12 +118,27 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 		if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
 			printk(KERN_WARNING "%s: discarding partial message\n",
 				 __func__);
-			return;
+			goto next_msg;
 		}
 
 		/*
-		 * We currently don't support anyone sending us a message
+		 * Deliver message to the appropriate transport
 		 */
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+
+		tport = hdr->transport;
+		if ((tport < SCSI_NL_MAX_TRANSPORTS) &&
+		    !(transports[tport].flags & HANDLER_DELETING) &&
+		    (transports[tport].msg_handler)) {
+			transports[tport].refcnt++;
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			err = transports[tport].msg_handler(skb);
+			spin_lock_irqsave(&scsi_nl_lock, flags);
+			transports[tport].refcnt--;
+		} else
+			err = -ENOENT;
+
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
 
 next_msg:
 		if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
@@ -110,14 +160,42 @@ static int
 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
 	struct netlink_notify *n = ptr;
+	struct scsi_nl_drvr *driver;
+	unsigned long flags;
+	int tport;
 
 	if (n->protocol != NETLINK_SCSITRANSPORT)
 		return NOTIFY_DONE;
 
+	spin_lock_irqsave(&scsi_nl_lock, flags);
+	scsi_nl_state |= STATE_EHANDLER_BSY;
+
 	/*
-	 * Currently, we are not tracking PID's, etc. There is nothing
-	 * to handle.
+	 * Pass event on to any transports that may be listening
 	 */
+	for (tport = 0; tport < SCSI_NL_MAX_TRANSPORTS; tport++) {
+		if (!(transports[tport].flags & HANDLER_DELETING) &&
+		    (transports[tport].event_handler)) {
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			transports[tport].event_handler(this, event, ptr);
+			spin_lock_irqsave(&scsi_nl_lock, flags);
+		}
+	}
+
+	/*
+	 * Pass event on to any drivers that may be listening
+	 */
+	list_for_each_entry(driver, &scsi_nl_drivers, next) {
+		if (!(driver->flags & HANDLER_DELETING) &&
+		    (driver->devt_handler)) {
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			driver->devt_handler(this, event, ptr);
+			spin_lock_irqsave(&scsi_nl_lock, flags);
+		}
+	}
+
+	scsi_nl_state &= ~STATE_EHANDLER_BSY;
+	spin_unlock_irqrestore(&scsi_nl_lock, flags);
 
 	return NOTIFY_DONE;
 }
@@ -128,7 +206,281 @@ static struct notifier_block scsi_netlink_notifier = {
 
 
 /**
- * scsi_netlink_init - Called by SCSI subsystem to intialize the SCSI transport netlink interface
+ * GENERIC SCSI transport receive and event handlers
+ **/
+
+/**
+ * scsi_generic_msg_handler - receive message handler for GENERIC transport
+ * 			 messages
+ *
+ * @skb:		socket receive buffer
+ *
+ **/
+static int
+scsi_generic_msg_handler(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+	struct scsi_nl_hdr *snlh = NLMSG_DATA(nlh);
+	struct scsi_nl_drvr *driver;
+	struct Scsi_Host *shost;
+	unsigned long flags;
+	int err = 0, match, pid;
+
+	pid = NETLINK_CREDS(skb)->pid;
+
+	switch (snlh->msgtype) {
+	case SCSI_NL_SHOST_VENDOR:
+		{
+		struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
+
+		/* Locate the driver that corresponds to the message */
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+		match = 0;
+		list_for_each_entry(driver, &scsi_nl_drivers, next) {
+			if (driver->vendor_id == msg->vendor_id) {
+				match = 1;
+				break;
+			}
+		}
+
+		if ((!match) || (!driver->dmsg_handler)) {
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			err = -ESRCH;
+			goto rcv_exit;
+		}
+
+		if (driver->flags & HANDLER_DELETING) {
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			err = -ESHUTDOWN;
+			goto rcv_exit;
+		}
+
+		driver->refcnt++;
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+
+		/* if successful, scsi_host_lookup takes a shost reference */
+		shost = scsi_host_lookup(msg->host_no);
+		if (!shost) {
+			err = -ENODEV;
+			goto driver_exit;
+		}
+
+		/* is this host owned by the vendor ? */
+		if (shost->hostt != driver->hostt) {
+			err = -EINVAL;
+			goto vendormsg_put;
+		}
+
+		/* pass message on to the driver */
+		err = driver->dmsg_handler(shost, (void *)&msg[1],
+					 msg->vmsg_datalen, pid);
+
+vendormsg_put:
+		/* release reference by scsi_host_lookup */
+		scsi_host_put(shost);
+
+driver_exit:
+		/* release our own reference on the registration object */
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+		driver->refcnt--;
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+		break;
+		}
+
+	default:
+		err = -EBADR;
+		break;
+	}
+
+rcv_exit:
+	if (err)
+		printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
+			 __func__, snlh->msgtype, err);
+	return err;
+}
+
+
+/**
+ * scsi_nl_add_transport -
+ *    Registers message and event handlers for a transport. Enables
+ *    receipt of netlink messages and events to a transport.
+ *
+ * @tport:		transport registering handlers
+ * @msg_handler:	receive message handler callback
+ * @event_handler:	receive event handler callback
+ **/
+int
+scsi_nl_add_transport(u8 tport,
+	int (*msg_handler)(struct sk_buff *),
+	void (*event_handler)(struct notifier_block *, unsigned long, void *))
+{
+	unsigned long flags;
+	int err = 0;
+
+	if (tport >= SCSI_NL_MAX_TRANSPORTS)
+		return -EINVAL;
+
+	spin_lock_irqsave(&scsi_nl_lock, flags);
+
+	if (scsi_nl_state & STATE_EHANDLER_BSY) {
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+		msleep(1);
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+	}
+
+	if (transports[tport].msg_handler || transports[tport].event_handler) {
+		err = -EALREADY;
+		goto register_out;
+	}
+
+	transports[tport].msg_handler = msg_handler;
+	transports[tport].event_handler = event_handler;
+	transports[tport].flags = 0;
+	transports[tport].refcnt = 0;
+
+register_out:
+	spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
+
+
+/**
+ * scsi_nl_remove_transport -
+ *    Disable transport receiption of messages and events
+ *
+ * @tport:		transport deregistering handlers
+ *
+ **/
+void
+scsi_nl_remove_transport(u8 tport)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&scsi_nl_lock, flags);
+	if (scsi_nl_state & STATE_EHANDLER_BSY) {
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+		msleep(1);
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+	}
+
+	if (tport < SCSI_NL_MAX_TRANSPORTS) {
+		transports[tport].flags |= HANDLER_DELETING;
+
+		while (transports[tport].refcnt != 0) {
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			schedule_timeout_uninterruptible(HZ/4);
+			spin_lock_irqsave(&scsi_nl_lock, flags);
+		}
+		transports[tport].msg_handler = NULL;
+		transports[tport].event_handler = NULL;
+		transports[tport].flags = 0;
+	}
+
+	spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+	return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
+
+
+/**
+ * scsi_nl_add_driver -
+ *    A driver is registering its interfaces for SCSI netlink messages
+ *
+ * @vendor_id:          A unique identification value for the driver.
+ * @hostt:		address of the driver's host template. Used
+ *			to verify an shost is bound to the driver
+ * @nlmsg_handler:	receive message handler callback
+ * @nlevt_handler:	receive event handler callback
+ *
+ * Returns:
+ *   0 on Success
+ *   error result otherwise
+ **/
+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))
+{
+	struct scsi_nl_drvr *driver;
+	unsigned long flags;
+
+	driver = kzalloc(sizeof(*driver), GFP_KERNEL);
+	if (unlikely(!driver)) {
+		printk(KERN_ERR "%s: allocation failure\n", __func__);
+		return -ENOMEM;
+	}
+
+	driver->dmsg_handler = nlmsg_handler;
+	driver->devt_handler = nlevt_handler;
+	driver->hostt = hostt;
+	driver->vendor_id = vendor_id;
+
+	spin_lock_irqsave(&scsi_nl_lock, flags);
+	if (scsi_nl_state & STATE_EHANDLER_BSY) {
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+		msleep(1);
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+	}
+	list_add_tail(&driver->next, &scsi_nl_drivers);
+	spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
+
+
+/**
+ * scsi_nl_remove_driver -
+ *    An driver is unregistering with the SCSI netlink messages
+ *
+ * @vendor_id:          The unique identification value for the driver.
+ **/
+void
+scsi_nl_remove_driver(u64 vendor_id)
+{
+	struct scsi_nl_drvr *driver;
+	unsigned long flags;
+
+	spin_lock_irqsave(&scsi_nl_lock, flags);
+	if (scsi_nl_state & STATE_EHANDLER_BSY) {
+		spin_unlock_irqrestore(&scsi_nl_lock, flags);
+		msleep(1);
+		spin_lock_irqsave(&scsi_nl_lock, flags);
+	}
+
+	list_for_each_entry(driver, &scsi_nl_drivers, next) {
+		if (driver->vendor_id == vendor_id) {
+			driver->flags |= HANDLER_DELETING;
+			while (driver->refcnt != 0) {
+				spin_unlock_irqrestore(&scsi_nl_lock, flags);
+				schedule_timeout_uninterruptible(HZ/4);
+				spin_lock_irqsave(&scsi_nl_lock, flags);
+			}
+			list_del(&driver->next);
+			kfree(driver);
+			spin_unlock_irqrestore(&scsi_nl_lock, flags);
+			return;
+		}
+	}
+
+	spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+	printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
+	       __func__, (unsigned long long)vendor_id);
+	return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
+
+
+/**
+ * scsi_netlink_init - Called by SCSI subsystem to intialize
+ * 	the SCSI transport netlink interface
  *
  **/
 void
@@ -136,6 +488,8 @@ scsi_netlink_init(void)
 {
 	int error;
 
+	INIT_LIST_HEAD(&scsi_nl_drivers);
+
 	error = netlink_register_notifier(&scsi_netlink_notifier);
 	if (error) {
 		printk(KERN_ERR "%s: register of event handler failed - %d\n",
@@ -150,8 +504,15 @@ scsi_netlink_init(void)
 		printk(KERN_ERR "%s: register of recieve handler failed\n",
 				__func__);
 		netlink_unregister_notifier(&scsi_netlink_notifier);
+		return;
 	}
 
+	/* Register the entry points for the generic SCSI transport */
+	error = scsi_nl_add_transport(SCSI_NL_TRANSPORT,
+				scsi_generic_msg_handler, NULL);
+	if (error)
+		printk(KERN_ERR "%s: register of GENERIC transport handler"
+				"  failed - %d\n", __func__, error);
 	return;
 }
 
@@ -163,6 +524,8 @@ scsi_netlink_init(void)
 void
 scsi_netlink_exit(void)
 {
+	scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
+
 	if (scsi_nl_sock) {
 		netlink_kernel_release(scsi_nl_sock);
 		netlink_unregister_notifier(&scsi_netlink_notifier);
@@ -172,3 +535,147 @@ scsi_netlink_exit(void)
 }
 
 
+/*
+ * Exported Interfaces
+ */
+
+/**
+ * scsi_nl_send_transport_msg -
+ *    Generic function to send a single message from a SCSI transport to
+ *    a single process
+ *
+ * @pid:		receiving pid
+ * @hdr:		message payload
+ *
+ **/
+void
+scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr	*nlh;
+	const char *fn;
+	char *datab;
+	u32 len, skblen;
+	int err;
+
+	if (!scsi_nl_sock) {
+		err = -ENOENT;
+		fn = "netlink socket";
+		goto msg_fail;
+	}
+
+	len = NLMSG_SPACE(hdr->msglen);
+	skblen = NLMSG_SPACE(len);
+
+	skb = alloc_skb(skblen, GFP_KERNEL);
+	if (!skb) {
+		err = -ENOBUFS;
+		fn = "alloc_skb";
+		goto msg_fail;
+	}
+
+	nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
+	if (!nlh) {
+		err = -ENOBUFS;
+		fn = "nlmsg_put";
+		goto msg_fail_skb;
+	}
+	datab = NLMSG_DATA(nlh);
+	memcpy(datab, hdr, hdr->msglen);
+
+	err = nlmsg_unicast(scsi_nl_sock, skb, pid);
+	if (err < 0) {
+		fn = "nlmsg_unicast";
+		/* nlmsg_unicast already kfree_skb'd */
+		goto msg_fail;
+	}
+
+	return;
+
+msg_fail_skb:
+	kfree_skb(skb);
+msg_fail:
+	printk(KERN_WARNING
+		"%s: Dropped Message : pid %d Transport %d, msgtype x%x, "
+		"msglen %d: %s : err %d\n",
+		__func__, pid, hdr->transport, hdr->msgtype, hdr->msglen,
+		fn, err);
+	return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
+
+
+/**
+ * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
+ *                      to a specific process id.
+ *
+ * @pid:		process id of the receiver
+ * @host_no:		host # sending the message
+ * @vendor_id:		unique identifier for the driver's vendor
+ * @data_len:		amount, in bytes, of vendor unique payload data
+ * @data_buf:		pointer to vendor unique data buffer
+ *
+ * Returns:
+ *   0 on succesful return
+ *   otherwise, failing error code
+ *
+ * Notes:
+ *	This routine assumes no locks are held on entry.
+ */
+int
+scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
+			 char *data_buf, u32 data_len)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr	*nlh;
+	struct scsi_nl_host_vendor_msg *msg;
+	u32 len, skblen;
+	int err;
+
+	if (!scsi_nl_sock) {
+		err = -ENOENT;
+		goto send_vendor_fail;
+	}
+
+	len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
+	skblen = NLMSG_SPACE(len);
+
+	skb = alloc_skb(skblen, GFP_KERNEL);
+	if (!skb) {
+		err = -ENOBUFS;
+		goto send_vendor_fail;
+	}
+
+	nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
+				skblen - sizeof(*nlh), 0);
+	if (!nlh) {
+		err = -ENOBUFS;
+		goto send_vendor_fail_skb;
+	}
+	msg = NLMSG_DATA(nlh);
+
+	INIT_SCSI_NL_HDR(&msg->snlh, SCSI_NL_TRANSPORT,
+				SCSI_NL_SHOST_VENDOR, len);
+	msg->vendor_id = vendor_id;
+	msg->host_no = host_no;
+	msg->vmsg_datalen = data_len;	/* bytes */
+	memcpy(&msg[1], data_buf, data_len);
+
+	err = nlmsg_unicast(scsi_nl_sock, skb, pid);
+	if (err)
+		/* nlmsg_multicast already kfree_skb'd */
+		goto send_vendor_fail;
+
+	return 0;
+
+send_vendor_fail_skb:
+	kfree_skb(skb);
+send_vendor_fail:
+	printk(KERN_WARNING
+		"%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
+		__func__, host_no, err);
+	return err;
+}
+EXPORT_SYMBOL(scsi_nl_send_vendor_msg);
+
+