[PATCH RFC 2/5 RESEND] add iscsi interface

[Mike Christie <michaelc@cs.wisc.edu>]

Add iscsi interface code (first user of libiscsi). Others
can use as much or as little depending on their transport
function template.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>

diff -Naurp linux-2.6.15-rc2/drivers/scsi/iscsi_if.c linux-2.6.15-rc2.diff/drivers/scsi/iscsi_if.c
--- linux-2.6.15-rc2/drivers/scsi/iscsi_if.c	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.15-rc2.diff/drivers/scsi/iscsi_if.c	2005-11-20 15:05:37.000000000 -0600
@@ -0,0 +1,1037 @@
+/*
+ * iSCSI transport class definitions
+ *
+ * Copyright (C) IBM Corporation, 2004
+ * Copyright (C) Mike Christie, 2004 - 2005
+ * Copyright (C) Dmitry Yusupov, 2004 - 2005
+ * Copyright (C) Alex Aizman, 2004 - 2005
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/module.h>
+#include <linux/mempool.h>
+#include <net/tcp.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_transport.h>
+#include <scsi/scsi_transport_iscsi.h>
+#include <scsi/iscsi_if.h>
+#include <scsi/iscsi_session.h>
+
+#define ISCSI_SESSION_ATTRS 8
+#define ISCSI_CONN_ATTRS 6
+
+struct iscsi_internal {
+	struct scsi_transport_template t;
+	struct iscsi_transport *iscsi_transport;
+	struct list_head list;
+	/*
+	 * List of sessions for this transport
+	 */
+	struct list_head sessions;
+	/*
+	 * based on transport capabilities, at register time we set these
+	 * bits to tell the transport class it wants attributes displayed
+	 * in sysfs or that it can support different iSCSI Data-Path
+	 * capabilities
+	 */
+	uint32_t param_mask;
+
+	struct class_device cdev;
+	/*
+	 * We do not have any private or other attrs.
+	 */
+	struct transport_container conn_cont;
+	struct class_device_attribute *conn_attrs[ISCSI_CONN_ATTRS + 1];
+	struct transport_container session_cont;
+	struct class_device_attribute *session_attrs[ISCSI_SESSION_ATTRS + 1];
+};
+
+/*
+ * list of registered transports and lock that must
+ * be held while accessing list. The iscsi_transport_lock must
+ * be acquired after the rx_queue_sema.
+ */
+static LIST_HEAD(iscsi_transports);
+static DEFINE_SPINLOCK(iscsi_transport_lock);
+
+#define to_iscsi_internal(tmpl) \
+	container_of(tmpl, struct iscsi_internal, t)
+
+#define cdev_to_iscsi_internal(_cdev) \
+	container_of(_cdev, struct iscsi_internal, cdev)
+
+static void iscsi_transport_release(struct class_device *cdev)
+{
+	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
+	kfree(priv);
+}
+
+/*
+ * iscsi_transport_class represents the iscsi_transports that are
+ * registered.
+ */
+static struct class iscsi_transport_class = {
+	.name = "iscsi_transport",
+	.release = iscsi_transport_release,
+};
+
+static ssize_t
+show_transport_handle(struct class_device *cdev, char *buf)
+{
+	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
+	return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
+}
+static CLASS_DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);
+
+#define show_transport_attr(name, format)				\
+static ssize_t								\
+show_transport_##name(struct class_device *cdev, char *buf)		\
+{									\
+	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);	\
+	return sprintf(buf, format"\n", priv->iscsi_transport->name);	\
+}									\
+static CLASS_DEVICE_ATTR(name, S_IRUGO, show_transport_##name, NULL);
+
+show_transport_attr(caps, "0x%x");
+show_transport_attr(max_lun, "%d");
+show_transport_attr(max_conn, "%d");
+show_transport_attr(max_cmd_len, "%d");
+
+static struct attribute *iscsi_transport_attrs[] = {
+	&class_device_attr_handle.attr,
+	&class_device_attr_caps.attr,
+	&class_device_attr_max_lun.attr,
+	&class_device_attr_max_conn.attr,
+	&class_device_attr_max_cmd_len.attr,
+	NULL,
+};
+
+static struct attribute_group iscsi_transport_group = {
+	.attrs = iscsi_transport_attrs,
+};
+
+static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
+			       "iscsi_session",
+			       NULL,
+			       NULL,
+			       NULL);
+
+static DECLARE_TRANSPORT_CLASS(iscsi_connection_class,
+			       "iscsi_connection",
+			       NULL,
+			       NULL,
+			       NULL);
+
+static struct sock *nls;
+static int daemon_pid;
+static DECLARE_MUTEX(rx_queue_sema);
+
+static struct mempool_zone z_reply;
+
+/*
+ * Z_MAX_* - actual mempool size allocated at the mempool_zone_init() time
+ * Z_HIWAT_* - zone's high watermark when if_error bit will be set to -ENOMEM
+ *             so daemon will notice OOM on NETLINK tranposrt level and will
+ *             be able to predict or change operational behavior
+ */
+#define Z_MAX_REPLY	8
+#define Z_HIWAT_REPLY	6
+#define Z_MAX_PDU	8
+#define Z_HIWAT_PDU	6
+#define Z_MAX_ERROR	16
+#define Z_HIWAT_ERROR	12
+
+static LIST_HEAD(connlist);
+static DEFINE_SPINLOCK(connlock);
+
+/*
+ * can we replace this with some sort of container of use
+ */
+static struct iscsi_conn*
+iscsi_if_find_conn(uint64_t key)
+{
+	unsigned long flags;
+	struct iscsi_conn *conn;
+
+	spin_lock_irqsave(&connlock, flags);
+	list_for_each_entry(conn, &connlist, conn_list)
+		if (conn->connh == key) {
+			spin_unlock_irqrestore(&connlock, flags);
+			return conn;
+		}
+	spin_unlock_irqrestore(&connlock, flags);
+	return NULL;
+}
+
+static struct iscsi_internal *
+iscsi_if_transport_lookup(struct iscsi_transport *tt)
+{
+	struct iscsi_internal *priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iscsi_transport_lock, flags);
+	list_for_each_entry(priv, &iscsi_transports, list) {
+		if (tt == priv->iscsi_transport) {
+			spin_unlock_irqrestore(&iscsi_transport_lock, flags);
+			return priv;
+		}
+	}
+	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
+	return NULL;
+}
+
+static inline struct list_head *skb_to_lh(struct sk_buff *skb)
+{
+	return (struct list_head *)&skb->cb;
+}
+
+static void*
+mempool_zone_alloc_skb(unsigned int gfp_mask, void *pool_data)
+{
+	struct mempool_zone *zone = pool_data;
+
+	return alloc_skb(zone->size, gfp_mask);
+}
+
+static void
+mempool_zone_free_skb(void *element, void *pool_data)
+{
+	kfree_skb(element);
+}
+
+static void
+mempool_zone_complete(struct mempool_zone *zone)
+{
+	unsigned long flags;
+	struct list_head *lh, *n;
+
+	spin_lock_irqsave(&zone->freelock, flags);
+	list_for_each_safe(lh, n, &zone->freequeue) {
+		struct sk_buff *skb = (struct sk_buff *)((char *)lh -
+				offsetof(struct sk_buff, cb));
+		if (!skb_shared(skb)) {
+			list_del(skb_to_lh(skb));
+			mempool_free(skb, zone->pool);
+			atomic_dec(&zone->allocated);
+		}
+	}
+	spin_unlock_irqrestore(&zone->freelock, flags);
+}
+
+static int
+mempool_zone_init(struct mempool_zone *zp, unsigned max, unsigned size,
+		unsigned hiwat)
+{
+	zp->pool = mempool_create(max, mempool_zone_alloc_skb,
+				  mempool_zone_free_skb, zp);
+	if (!zp->pool)
+		return -ENOMEM;
+
+	zp->size = size;
+	zp->hiwat = hiwat;
+
+	INIT_LIST_HEAD(&zp->freequeue);
+	spin_lock_init(&zp->freelock);
+	atomic_set(&zp->allocated, 0);
+
+	return 0;
+}
+
+
+static struct sk_buff*
+mempool_zone_get_skb(struct mempool_zone *zone)
+{
+	struct sk_buff *skb;
+
+	skb = mempool_alloc(zone->pool, GFP_ATOMIC);
+	if (skb)
+		atomic_inc(&zone->allocated);
+	return skb;
+}
+
+static int
+iscsi_unicast_skb(struct mempool_zone *zone, struct sk_buff *skb)
+{
+	unsigned long flags;
+	int rc;
+
+	skb_get(skb);
+	rc = netlink_unicast(nls, skb, daemon_pid, MSG_DONTWAIT);
+	if (rc < 0) {
+		mempool_free(skb, zone->pool);
+		printk(KERN_ERR "iscsi: can not unicast skb (%d)\n", rc);
+		return rc;
+	}
+
+	spin_lock_irqsave(&zone->freelock, flags);
+	list_add(skb_to_lh(skb), &zone->freequeue);
+	spin_unlock_irqrestore(&zone->freelock, flags);
+
+	return 0;
+}
+
+int iscsi_recv_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr,
+		   char *data, uint32_t data_size)
+{
+	struct nlmsghdr	*nlh;
+	struct sk_buff *skb;
+	struct iscsi_uevent *ev;
+	struct iscsi_conn *conn;
+	char *pdu;
+	int len = NLMSG_SPACE(sizeof(*ev) + sizeof(struct iscsi_hdr) +
+			      data_size);
+
+	conn = iscsi_if_find_conn(connh);
+	BUG_ON(!conn);
+
+	mempool_zone_complete(&conn->z_pdu);
+
+	skb = mempool_zone_get_skb(&conn->z_pdu);
+	if (!skb) {
+		iscsi_conn_error(connh, ISCSI_ERR_CONN_FAILED);
+		dev_printk(KERN_ERR, &conn->dev, "iscsi: can not deliver "
+			   "control PDU: OOM\n");
+		return -ENOMEM;
+	}
+
+	nlh = __nlmsg_put(skb, daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
+	ev = NLMSG_DATA(nlh);
+	memset(ev, 0, sizeof(*ev));
+	ev->transport_handle = iscsi_handle(conn->transport);
+	ev->type = ISCSI_KEVENT_RECV_PDU;
+	if (atomic_read(&conn->z_pdu.allocated) >= conn->z_pdu.hiwat)
+		ev->iferror = -ENOMEM;
+	ev->r.recv_req.conn_handle = connh;
+	pdu = (char*)ev + sizeof(*ev);
+	memcpy(pdu, hdr, sizeof(struct iscsi_hdr));
+	memcpy(pdu + sizeof(struct iscsi_hdr), data, data_size);
+
+	return iscsi_unicast_skb(&conn->z_pdu, skb);
+}
+EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
+
+void iscsi_conn_error(iscsi_connh_t connh, enum iscsi_err error)
+{
+	struct nlmsghdr	*nlh;
+	struct sk_buff	*skb;
+	struct iscsi_uevent *ev;
+	struct iscsi_conn *conn;
+	int len = NLMSG_SPACE(sizeof(*ev));
+
+	conn = iscsi_if_find_conn(connh);
+	BUG_ON(!conn);
+
+	mempool_zone_complete(&conn->z_error);
+
+	skb = mempool_zone_get_skb(&conn->z_error);
+	if (!skb) {
+		dev_printk(KERN_ERR, &conn->dev, "iscsi: gracefully ignored "
+			  "conn error (%d)\n", error);
+		return;
+	}
+
+	nlh = __nlmsg_put(skb, daemon_pid, 0, 0, (len - sizeof(*nlh)), 0);
+	ev = NLMSG_DATA(nlh);
+	ev->transport_handle = iscsi_handle(conn->transport);
+	ev->type = ISCSI_KEVENT_CONN_ERROR;
+	if (atomic_read(&conn->z_error.allocated) >= conn->z_error.hiwat)
+		ev->iferror = -ENOMEM;
+	ev->r.connerror.error = error;
+	ev->r.connerror.conn_handle = connh;
+
+	iscsi_unicast_skb(&conn->z_error, skb);
+
+	dev_printk(KERN_INFO, &conn->dev, "iscsi: detected conn error (%d)\n",
+		   error);
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_error);
+
+static int
+iscsi_if_send_reply(int pid, int seq, int type, int done, int multi,
+		      void *payload, int size)
+{
+	struct sk_buff	*skb;
+	struct nlmsghdr	*nlh;
+	int len = NLMSG_SPACE(size);
+	int flags = multi ? NLM_F_MULTI : 0;
+	int t = done ? NLMSG_DONE : type;
+
+	mempool_zone_complete(&z_reply);
+
+	skb = mempool_zone_get_skb(&z_reply);
+	/*
+	 * FIXME:
+	 * user is supposed to react on iferror == -ENOMEM;
+	 * see iscsi_if_rx().
+	 */
+	BUG_ON(!skb);
+
+	nlh = __nlmsg_put(skb, pid, seq, t, (len - sizeof(*nlh)), 0);
+	nlh->nlmsg_flags = flags;
+	memcpy(NLMSG_DATA(nlh), payload, size);
+	return iscsi_unicast_skb(&z_reply, skb);
+}
+
+static int
+iscsi_if_create_session(struct iscsi_uevent *ev)
+{
+	struct iscsi_session *session;
+	struct Scsi_Host *shost;
+	struct iscsi_host *ihost;
+
+	ihost = iscsi_find_iscsi_host(ev->u.c_session.host_id);
+	if (!ihost) {
+		printk(KERN_ERR "iscsi: could not find iscsi host %s\n",
+		       ev->u.c_session.host_id);
+		return -EINVAL;
+	}
+
+	session = iscsi_create_session(ihost, ev->u.c_session.initial_cmdsn);
+	if (!session) {
+		ev->r.c_session_ret.session_handle = iscsi_handle(NULL);
+		return -ENOMEM;
+	}
+
+	shost = iscsi_session_to_shost(session);
+
+	ev->r.c_session_ret.session_handle = iscsi_handle(iscsi_hostdata(shost->hostdata));
+	ev->r.c_session_ret.sid = shost->host_no;
+	return 0;
+}
+
+static int
+iscsi_if_destroy_session(struct iscsi_uevent *ev)
+{
+	struct Scsi_Host *shost;
+	struct iscsi_session *session;
+
+	shost = scsi_host_lookup(ev->u.d_session.sid);
+	if (shost == ERR_PTR(-ENXIO))
+		return -EEXIST;
+
+	session = hostdata_session(shost->hostdata);
+	iscsi_destroy_session(session);
+
+	/* ref from host lookup */
+	scsi_host_put(shost);
+	return 0;
+}
+
+static int
+iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
+{
+	struct iscsi_session *session;
+	struct Scsi_Host *shost;
+	struct iscsi_conn *conn;
+	unsigned long flags;
+	int error;
+
+	shost = scsi_host_lookup(ev->u.c_conn.sid);
+	if (shost == ERR_PTR(-ENXIO))
+		return -EEXIST;
+	session = hostdata_session(shost->hostdata);
+
+	conn = iscsi_create_conn(session, ev->u.c_conn.cid);
+	if (!conn) {
+		error = -ENOMEM;
+		goto release_ref;
+	}
+
+	error = mempool_zone_init(&conn->z_pdu, Z_MAX_PDU,
+			NLMSG_SPACE(sizeof(struct iscsi_uevent) +
+				    sizeof(struct iscsi_hdr) +
+				    DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH),
+			Z_HIWAT_PDU);
+	if (error) {
+		dev_printk(KERN_ERR, &session->dev, "iscsi: can not allocate "
+			   "pdu zone for new conn\n");
+		goto destroy_conn;
+	}
+	error = mempool_zone_init(&conn->z_error, Z_MAX_ERROR,
+			NLMSG_SPACE(sizeof(struct iscsi_uevent)),
+			Z_HIWAT_ERROR);
+	if (error) {
+		dev_printk(KERN_ERR, &session->dev, "iscsi: can not allocate "
+			   "error zone for new conn\n");
+		goto free_pdu_pool;
+	}
+
+	ev->r.handle = conn->connh = iscsi_handle(conn->dd_data);
+
+	spin_lock_irqsave(&connlock, flags);
+	list_add(&conn->conn_list, &connlist);
+	conn->active = 1;
+	spin_unlock_irqrestore(&connlock, flags);
+
+	scsi_host_put(shost);
+	return 0;
+
+free_pdu_pool:
+	mempool_destroy(conn->z_pdu.pool);
+destroy_conn:
+	iscsi_destroy_conn(conn);
+release_ref:
+	scsi_host_put(shost);
+	return error;
+}
+
+static int
+iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
+{
+	unsigned long flags;
+	struct iscsi_conn *conn;
+
+	conn = iscsi_if_find_conn(ev->u.d_conn.conn_handle);
+	if (!conn)
+		return -EEXIST;
+
+	spin_lock_irqsave(&connlock, flags);
+	conn->active = 0;
+	list_del(&conn->conn_list);
+	spin_unlock_irqrestore(&connlock, flags);
+
+	mempool_destroy(conn->z_pdu.pool);
+	mempool_destroy(conn->z_error.pool);
+
+	iscsi_destroy_conn(conn);
+	return 0;
+}
+
+static int
+iscsi_if_get_stats(struct iscsi_transport *transport, struct sk_buff *skb,
+		   struct nlmsghdr *nlh)
+{
+	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
+	struct iscsi_stats *stats;
+	struct sk_buff *skbstat;
+	struct iscsi_conn *conn;
+	struct nlmsghdr	*nlhstat;
+	struct iscsi_uevent *evstat;
+	int len = NLMSG_SPACE(sizeof(*ev) +
+			      sizeof(struct iscsi_stats) +
+			      sizeof(struct iscsi_stats_custom) *
+			      ISCSI_STATS_CUSTOM_MAX);
+	int err = 0;
+
+	conn = iscsi_if_find_conn(ev->u.get_stats.conn_handle);
+	if (!conn)
+		return -EEXIST;
+
+	do {
+		int actual_size;
+
+		mempool_zone_complete(&conn->z_pdu);
+
+		skbstat = mempool_zone_get_skb(&conn->z_pdu);
+		if (!skbstat) {
+			dev_printk(KERN_ERR, &conn->dev, "iscsi: can not "
+				   "deliver stats: OOM\n");
+			return -ENOMEM;
+		}
+
+		nlhstat = __nlmsg_put(skbstat, daemon_pid, 0, 0,
+				      (len - sizeof(*nlhstat)), 0);
+		evstat = NLMSG_DATA(nlhstat);
+		memset(evstat, 0, sizeof(*evstat));
+		evstat->transport_handle = iscsi_handle(conn->transport);
+		evstat->type = nlh->nlmsg_type;
+		if (atomic_read(&conn->z_pdu.allocated) >= conn->z_pdu.hiwat)
+			evstat->iferror = -ENOMEM;
+		evstat->u.get_stats.conn_handle =
+			ev->u.get_stats.conn_handle;
+		stats = (struct iscsi_stats *)
+			((char*)evstat + sizeof(*evstat));
+		memset(stats, 0, sizeof(*stats));
+
+		transport->get_stats(ev->u.get_stats.conn_handle, stats);
+		actual_size = NLMSG_SPACE(sizeof(struct iscsi_uevent) +
+					  sizeof(struct iscsi_stats) +
+					  sizeof(struct iscsi_stats_custom) *
+					  stats->custom_length);
+		actual_size -= sizeof(*nlhstat);
+		actual_size = NLMSG_LENGTH(actual_size);
+		skb_trim(skb, NLMSG_ALIGN(actual_size));
+		nlhstat->nlmsg_len = actual_size;
+
+		err = iscsi_unicast_skb(&conn->z_pdu, skbstat);
+	} while (err < 0 && err != -ECONNREFUSED);
+
+	return err;
+}
+
+static int
+iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+	int err = 0;
+	struct iscsi_uevent *ev = NLMSG_DATA(nlh);
+	struct iscsi_transport *transport = NULL;
+	struct iscsi_internal *priv;
+
+	if (NETLINK_CREDS(skb)->uid)
+		return -EPERM;
+
+	priv = iscsi_if_transport_lookup(iscsi_ptr(ev->transport_handle));
+	if (!priv)
+		return -EINVAL;
+	transport = priv->iscsi_transport;
+
+	daemon_pid = NETLINK_CREDS(skb)->pid;
+
+	switch (nlh->nlmsg_type) {
+	case ISCSI_UEVENT_CREATE_SESSION:
+		err = iscsi_if_create_session(ev);
+		break;
+	case ISCSI_UEVENT_DESTROY_SESSION:
+		err = iscsi_if_destroy_session(ev);
+		break;
+	case ISCSI_UEVENT_CREATE_CONN:
+		err = iscsi_if_create_conn(transport, ev);
+		break;
+	case ISCSI_UEVENT_DESTROY_CONN:
+		err = iscsi_if_destroy_conn(transport, ev);
+		break;
+	case ISCSI_UEVENT_BIND_CONN:
+		if (!iscsi_if_find_conn(ev->u.b_conn.conn_handle))
+			return -EEXIST;
+		ev->r.retcode = transport->bind_conn(
+			ev->u.b_conn.session_handle,
+			ev->u.b_conn.conn_handle,
+			ev->u.b_conn.transport_fd,
+			ev->u.b_conn.is_leading);
+		break;
+	case ISCSI_UEVENT_SET_PARAM:
+		if (!iscsi_if_find_conn(ev->u.set_param.conn_handle))
+			return -EEXIST;
+		ev->r.retcode = transport->set_param(
+			ev->u.set_param.conn_handle,
+			ev->u.set_param.param, ev->u.set_param.value);
+		break;
+	case ISCSI_UEVENT_START_CONN:
+		if (!iscsi_if_find_conn(ev->u.start_conn.conn_handle))
+			return -EEXIST;
+		ev->r.retcode = transport->start_conn(
+			ev->u.start_conn.conn_handle);
+		break;
+	case ISCSI_UEVENT_STOP_CONN:
+		if (!iscsi_if_find_conn(ev->u.stop_conn.conn_handle))
+			return -EEXIST;
+		transport->stop_conn(ev->u.stop_conn.conn_handle,
+			ev->u.stop_conn.flag);
+		break;
+	case ISCSI_UEVENT_SEND_PDU:
+		if (!iscsi_if_find_conn(ev->u.send_pdu.conn_handle))
+			return -EEXIST;
+		ev->r.retcode = transport->send_pdu(
+		       ev->u.send_pdu.conn_handle,
+		       (struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
+		       (char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
+			ev->u.send_pdu.data_size);
+		break;
+	case ISCSI_UEVENT_GET_STATS:
+		err = iscsi_if_get_stats(transport, skb, nlh);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+/* Get message from skb (based on rtnetlink_rcv_skb).  Each message is
+ * processed by iscsi_if_recv_msg.  Malformed skbs with wrong length are
+ * discarded silently.  */
+static void
+iscsi_if_rx(struct sock *sk, int len)
+{
+	struct sk_buff *skb;
+
+	down(&rx_queue_sema);
+	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+		while (skb->len >= NLMSG_SPACE(0)) {
+			int err;
+			uint32_t rlen;
+			struct nlmsghdr	*nlh;
+			struct iscsi_uevent *ev;
+
+			nlh = (struct nlmsghdr *)skb->data;
+			if (nlh->nlmsg_len < sizeof(*nlh) ||
+			    skb->len < nlh->nlmsg_len) {
+				break;
+			}
+			ev = NLMSG_DATA(nlh);
+			rlen = NLMSG_ALIGN(nlh->nlmsg_len);
+			if (rlen > skb->len)
+				rlen = skb->len;
+			err = iscsi_if_recv_msg(skb, nlh);
+			if (err) {
+				ev->type = ISCSI_KEVENT_IF_ERROR;
+				ev->iferror = err;
+			}
+			do {
+				/*
+				 * special case for GET_STATS:
+				 * on success - sending reply and stats from
+				 * inside of if_recv_msg(),
+				 * on error - fall through.
+				 */
+				if (ev->type == ISCSI_UEVENT_GET_STATS && !err)
+					break;
+				err = iscsi_if_send_reply(
+					NETLINK_CREDS(skb)->pid, nlh->nlmsg_seq,
+					nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
+				if (atomic_read(&z_reply.allocated) >=
+						z_reply.hiwat)
+					ev->iferror = -ENOMEM;
+			} while (err < 0 && err != -ECONNREFUSED);
+			skb_pull(skb, rlen);
+		}
+		kfree_skb(skb);
+	}
+	up(&rx_queue_sema);
+}
+
+#define iscsi_cdev_to_conn(_cdev) \
+	iscsi_dev_to_conn(_cdev->dev)
+
+/*
+ * iSCSI connection attrs
+ */
+#define iscsi_conn_int_attr_show(param, format)				\
+static ssize_t								\
+show_conn_int_param_##param(struct class_device *cdev, char *buf)	\
+{									\
+	uint32_t value = 0;						\
+	struct iscsi_conn *conn = iscsi_cdev_to_conn(cdev);		\
+	struct iscsi_session *session = iscsi_dev_to_session(conn->dev.parent);\
+	struct iscsi_transport *t = session->ihost->iscsi_transport;	\
+									\
+	t->get_conn_param(conn->dd_data, param, &value);		\
+	return snprintf(buf, 20, format"\n", value);			\
+}
+
+#define iscsi_conn_int_attr(field, param, format)			\
+	iscsi_conn_int_attr_show(param, format)				\
+static CLASS_DEVICE_ATTR(field, S_IRUGO, show_conn_int_param_##param, NULL);
+
+iscsi_conn_int_attr(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH, "%u");
+iscsi_conn_int_attr(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH, "%u");
+iscsi_conn_int_attr(header_digest, ISCSI_PARAM_HDRDGST_EN, "%d");
+iscsi_conn_int_attr(data_digest, ISCSI_PARAM_DATADGST_EN, "%d");
+iscsi_conn_int_attr(ifmarker, ISCSI_PARAM_IFMARKER_EN, "%d");
+iscsi_conn_int_attr(ofmarker, ISCSI_PARAM_OFMARKER_EN, "%d");
+
+#define iscsi_cdev_to_session(_cdev) \
+	iscsi_dev_to_session(_cdev->dev)
+
+/*
+ * iSCSI session attrs
+ */
+#define iscsi_session_int_attr_show(param, format)			\
+static ssize_t								\
+show_session_int_param_##param(struct class_device *cdev, char *buf)	\
+{									\
+	uint32_t value = 0;						\
+	struct iscsi_session *session = iscsi_cdev_to_session(cdev);	\
+	struct Scsi_Host *shost = iscsi_session_to_shost(session);	\
+	struct iscsi_transport *t = session->ihost->iscsi_transport;	\
+									\
+	t->get_session_param(shost, param, &value);			\
+	return snprintf(buf, 20, format"\n", value);			\
+}
+
+#define iscsi_session_int_attr(field, param, format)			\
+	iscsi_session_int_attr_show(param, format)			\
+static CLASS_DEVICE_ATTR(field, S_IRUGO, show_session_int_param_##param, NULL);
+
+iscsi_session_int_attr(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN, "%d");
+iscsi_session_int_attr(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T, "%hu");
+iscsi_session_int_attr(immediate_data, ISCSI_PARAM_IMM_DATA_EN, "%d");
+iscsi_session_int_attr(first_burst_len, ISCSI_PARAM_FIRST_BURST, "%u");
+iscsi_session_int_attr(max_burst_len, ISCSI_PARAM_MAX_BURST, "%u");
+iscsi_session_int_attr(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN, "%d");
+iscsi_session_int_attr(data_seq_in_order, ISCSI_PARAM_DATASEQ_INORDER_EN, "%d");
+iscsi_session_int_attr(erl, ISCSI_PARAM_ERL, "%d");
+
+#define SETUP_SESSION_RD_ATTR(field, param)				\
+	if (priv->param_mask & (1 << param)) {				\
+		priv->session_attrs[count] = &class_device_attr_##field;\
+		count++;						\
+	}
+
+#define SETUP_CONN_RD_ATTR(field, param)				\
+	if (priv->param_mask & (1 << param)) {				\
+		priv->conn_attrs[count] = &class_device_attr_##field;	\
+		count++;						\
+	}
+
+static int iscsi_session_match(struct attribute_container *cont,
+			   struct device *dev)
+{
+	struct iscsi_session *session;
+	struct Scsi_Host *shost;
+	struct iscsi_internal *priv;
+
+	if (!iscsi_is_session_dev(dev))
+		return 0;
+
+	session = iscsi_dev_to_session(dev);
+	shost = iscsi_session_to_shost(session);
+	if (!shost->transportt)
+		return 0;
+
+	priv = to_iscsi_internal(shost->transportt);
+	if (priv->session_cont.ac.class != &iscsi_session_class.class)
+		return 0;
+
+	return &priv->session_cont.ac == cont;
+}
+
+static int iscsi_conn_match(struct attribute_container *cont,
+			   struct device *dev)
+{
+	struct iscsi_session *session;
+	struct iscsi_conn *conn;
+	struct Scsi_Host *shost;
+	struct iscsi_internal *priv;
+
+	if (!iscsi_is_conn_dev(dev))
+		return 0;
+
+	conn = iscsi_dev_to_conn(dev);
+	session = iscsi_dev_to_session(conn->dev.parent);
+	shost = iscsi_session_to_shost(session);
+
+	if (!shost->transportt)
+		return 0;
+
+	priv = to_iscsi_internal(shost->transportt);
+	if (priv->conn_cont.ac.class != &iscsi_connection_class.class)
+		return 0;
+
+	return &priv->conn_cont.ac == cont;
+}
+
+struct scsi_transport_template *
+iscsi_register_transport(struct iscsi_transport *tt)
+{
+	struct iscsi_internal *priv;
+	unsigned long flags;
+	int count = 0, err;
+
+	BUG_ON(!tt);
+
+	priv = iscsi_if_transport_lookup(tt);
+	if (priv)
+		return NULL;
+
+	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return NULL;
+	memset(priv, 0, sizeof(*priv));
+	INIT_LIST_HEAD(&priv->list);
+	INIT_LIST_HEAD(&priv->sessions);
+	priv->iscsi_transport = tt;
+
+	priv->cdev.class = &iscsi_transport_class;
+	snprintf(priv->cdev.class_id, BUS_ID_SIZE, "%s", tt->name);
+	err = class_device_register(&priv->cdev);
+	if (err)
+		goto free_priv;
+
+	err = sysfs_create_group(&priv->cdev.kobj, &iscsi_transport_group);
+	if (err)
+		goto unregister_cdev;
+
+	/* setup parameters mask */
+	priv->param_mask = 0xFFFFFFFF;
+	if (!(tt->caps & CAP_MULTI_R2T))
+		priv->param_mask &= ~(1 << ISCSI_PARAM_MAX_R2T);
+	if (!(tt->caps & CAP_HDRDGST))
+		priv->param_mask &= ~(1 << ISCSI_PARAM_HDRDGST_EN);
+	if (!(tt->caps & CAP_DATADGST))
+		priv->param_mask &= ~(1 << ISCSI_PARAM_DATADGST_EN);
+	if (!(tt->caps & CAP_MARKERS)) {
+		priv->param_mask &= ~(1 << ISCSI_PARAM_IFMARKER_EN);
+		priv->param_mask &= ~(1 << ISCSI_PARAM_OFMARKER_EN);
+	}
+
+	/* connection parameters */
+	priv->conn_cont.ac.attrs = &priv->conn_attrs[0];
+	priv->conn_cont.ac.class = &iscsi_connection_class.class;
+	priv->conn_cont.ac.match = iscsi_conn_match;
+	transport_container_register(&priv->conn_cont);
+
+	SETUP_CONN_RD_ATTR(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH);
+	SETUP_CONN_RD_ATTR(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH);
+	SETUP_CONN_RD_ATTR(header_digest, ISCSI_PARAM_HDRDGST_EN);
+	SETUP_CONN_RD_ATTR(data_digest, ISCSI_PARAM_DATADGST_EN);
+	SETUP_CONN_RD_ATTR(ifmarker, ISCSI_PARAM_IFMARKER_EN);
+	SETUP_CONN_RD_ATTR(ofmarker, ISCSI_PARAM_OFMARKER_EN);
+
+	BUG_ON(count > ISCSI_CONN_ATTRS);
+	priv->conn_attrs[count] = NULL;
+	count = 0;
+
+	/* session parameters */
+	priv->session_cont.ac.attrs = &priv->session_attrs[0];
+	priv->session_cont.ac.class = &iscsi_session_class.class;
+	priv->session_cont.ac.match = iscsi_session_match;
+	transport_container_register(&priv->session_cont);
+
+	SETUP_SESSION_RD_ATTR(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN);
+	SETUP_SESSION_RD_ATTR(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T);
+	SETUP_SESSION_RD_ATTR(immediate_data, ISCSI_PARAM_IMM_DATA_EN);
+	SETUP_SESSION_RD_ATTR(first_burst_len, ISCSI_PARAM_FIRST_BURST);
+	SETUP_SESSION_RD_ATTR(max_burst_len, ISCSI_PARAM_MAX_BURST);
+	SETUP_SESSION_RD_ATTR(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN);
+	SETUP_SESSION_RD_ATTR(data_seq_in_order,ISCSI_PARAM_DATASEQ_INORDER_EN)
+	SETUP_SESSION_RD_ATTR(erl, ISCSI_PARAM_ERL);
+
+	BUG_ON(count > ISCSI_SESSION_ATTRS);
+	priv->session_attrs[count] = NULL;
+
+	spin_lock_irqsave(&iscsi_transport_lock, flags);
+	list_add(&priv->list, &iscsi_transports);
+	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
+
+	printk(KERN_NOTICE "iscsi: registered transport (%s)\n", tt->name);
+	return &priv->t;
+
+unregister_cdev:
+	class_device_unregister(&priv->cdev);
+free_priv:
+	kfree(priv);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(iscsi_register_transport);
+
+int iscsi_unregister_transport(struct iscsi_transport *tt)
+{
+	struct iscsi_internal *priv;
+	unsigned long flags;
+
+	BUG_ON(!tt);
+
+	down(&rx_queue_sema);
+
+	priv = iscsi_if_transport_lookup(tt);
+	BUG_ON (!priv);
+
+	spin_lock_irqsave(&iscsi_transport_lock, flags);
+	list_del(&priv->list);
+	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
+
+	transport_container_unregister(&priv->conn_cont);
+	transport_container_unregister(&priv->session_cont);
+
+	sysfs_remove_group(&priv->cdev.kobj, &iscsi_transport_group);
+	class_device_unregister(&priv->cdev);
+	up(&rx_queue_sema);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_unregister_transport);
+
+static int
+iscsi_rcv_nl_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	struct netlink_notify *n = ptr;
+
+	if (event == NETLINK_URELEASE &&
+	    n->protocol == NETLINK_ISCSI && n->pid) {
+		struct iscsi_conn *conn;
+		unsigned long flags;
+
+		mempool_zone_complete(&z_reply);
+		spin_lock_irqsave(&connlock, flags);
+		list_for_each_entry(conn, &connlist, conn_list) {
+			mempool_zone_complete(&conn->z_error);
+			mempool_zone_complete(&conn->z_pdu);
+		}
+		spin_unlock_irqrestore(&connlock, flags);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block iscsi_nl_notifier = {
+	.notifier_call	= iscsi_rcv_nl_event,
+};
+
+static __init int iscsi_transport_init(void)
+{
+	int err;
+
+	err = class_register(&iscsi_transport_class);
+	if (err)
+		return err;
+
+	err = transport_class_register(&iscsi_connection_class);
+	if (err)
+		goto unregister_transport_class;
+
+	err = transport_class_register(&iscsi_session_class);
+	if (err)
+		goto unregister_conn_class;
+
+	err = netlink_register_notifier(&iscsi_nl_notifier);
+	if (err)
+		goto unregister_session_class;
+
+	nls = netlink_kernel_create(NETLINK_ISCSI, 1, iscsi_if_rx,
+			THIS_MODULE);
+	if (!nls) {
+		err = -ENOBUFS;
+		goto unregister_notifier;
+	}
+
+	err = mempool_zone_init(&z_reply, Z_MAX_REPLY,
+		NLMSG_SPACE(sizeof(struct iscsi_uevent)), Z_HIWAT_REPLY);
+	if (!err)
+		return 0;
+
+	sock_release(nls->sk_socket);
+unregister_notifier:
+	netlink_unregister_notifier(&iscsi_nl_notifier);
+unregister_session_class:
+	transport_class_unregister(&iscsi_session_class);
+unregister_conn_class:
+	transport_class_unregister(&iscsi_connection_class);
+unregister_transport_class:
+	class_unregister(&iscsi_transport_class);
+	return err;
+}
+
+static void __exit iscsi_transport_exit(void)
+{
+	mempool_destroy(z_reply.pool);
+	sock_release(nls->sk_socket);
+	netlink_unregister_notifier(&iscsi_nl_notifier);
+	transport_class_unregister(&iscsi_connection_class);
+	transport_class_unregister(&iscsi_session_class);
+	class_unregister(&iscsi_transport_class);
+}
+
+module_init(iscsi_transport_init);
+module_exit(iscsi_transport_exit);
+
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
+	      "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
+	      "Alex Aizman <itn780@yahoo.com>");
+MODULE_DESCRIPTION("iSCSI Transport Interface");
+MODULE_LICENSE("GPL");
diff -Naurp linux-2.6.15-rc2/include/scsi/iscsi_if.h linux-2.6.15-rc2.diff/include/scsi/iscsi_if.h
--- linux-2.6.15-rc2/include/scsi/iscsi_if.h	2005-11-19 21:25:03.000000000 -0600
+++ linux-2.6.15-rc2.diff/include/scsi/iscsi_if.h	2005-11-20 15:05:12.000000000 -0600
@@ -58,6 +58,7 @@ struct iscsi_uevent {
 		/* messages u -> k */
 		struct msg_create_session {
 			uint32_t	initial_cmdsn;
+			char		host_id[20];
 		} c_session;
 		struct msg_destroy_session {
 			uint64_t	session_handle;