diff options
Diffstat (limited to 'drivers/scsi/scsi_netlink.c')
| -rw-r--r-- | drivers/scsi/scsi_netlink.c | 523 |
1 files changed, 515 insertions, 8 deletions
diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c index ae7ed9a2266..b37e133de80 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); + + |