From: Marcus Barrow <mbarrow@redhat.com>
Date: Fri, 5 Dec 2008 14:17:05 -0500
Subject: [scsi] qla4xxx: increase iscsi session check to 3-tuple
Message-id: 20081205191705.8992.88249.sendpatchset@file.bos.redhat.com
O-Subject: [rhel 5.3 bug] qla4xxx - Add checks for <TargetName, ISID, TargetPortGroupTag>
Bugzilla: 474736
RH-Acked-by: Mike Christie <mchristi@redhat.com>
RH-Acked-by: Rob Evers <revers@redhat.com>
RH-Nacked-by: Mike Christie <mchristi@redhat.com>

BZ 474736 - qla4xxx - Add checks for <TargetName, ISID, TargetPortGroupTag>

This is an extremely important patch, fixing an issue reported by NetApp. It could potentially make a customer's data become un-available.

Here is a description from the BZ, as I don't completely understand the iSCSI world:

Add checks for <TargetName, ISID, TargetPortGroupTag>

The enclosed patch fixes the problem.

In iSCSI world a session encapsulates an Initiator-Target Nexus. The current
inbox RHEL5.x driver uses the iSCSI TargetName (hence the <iSCSITargetName,
iSCSIInitiatorName> tuple) to uniquely identify an iSCSI Session.

This is however insufficient, when a Target Node (identified by an iSCSIName)
can be accessed via multiple portals (identified by an IP Address or DNS
assigned TargetHostName, tcp port#, portal group tag). This is the problem with
the NetApp. Configuration.

           || Port A (IP1/DNS Name) ||  Port B (IP2 or DNS Name)
           ||                       ||
      +---------------------------------------------+
      |                                             |
 |    +------------------------------------+   |
 |    | NetApp.Target (unique iSCSIName)   |   |
 |    +------------------------------------+   |
 +---------------------------------------------+

As per spec., each iSCSI Session is uniquely identified by the 4-tuple
<initiator Name, TargetName, ISID, TargetPortGroupTag>. Since InitiatorName is
a constant in our case this reduces to a 3-tuple <TargetName, ISID,
TargetPortGroupTag>

Remember that the ISID effectively encapsulates Target IP (or DNS assigned
Target Host Name) and the TCP Port the target is listening on.

The fix essentially checks for <TargetName, ISID, TargetPortGroupTag> instead
of just the TargetName.

Patches and builds cleanly on 2.6.18-123 cleanly. Tested at QLogic and NetApp...

diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h
index a517ca2..97caead 100644
--- a/drivers/scsi/qla4xxx/ql4_def.h
+++ b/drivers/scsi/qla4xxx/ql4_def.h
@@ -234,6 +234,8 @@ struct ddb_entry {
 	uint8_t ip_addr[ISCSI_IPADDR_SIZE];
 	uint8_t iscsi_name[ISCSI_NAME_SIZE];	/* 72 x48 */
 	uint8_t iscsi_alias[0x20];
+	uint8_t isid[6];
+	uint8_t rsrvd[2];
 };
 
 /*
diff --git a/drivers/scsi/qla4xxx/ql4_init.c b/drivers/scsi/qla4xxx/ql4_init.c
index a61beed..f22a9ba 100644
--- a/drivers/scsi/qla4xxx/ql4_init.c
+++ b/drivers/scsi/qla4xxx/ql4_init.c
@@ -355,8 +355,12 @@ static struct ddb_entry* qla4xxx_get_ddb_entry(struct scsi_qla_host *ha,
 	DEBUG2(printk("scsi%ld: %s: Looking for ddb[%d]\n", ha->host_no,
 		      __func__, fw_ddb_index));
 	list_for_each_entry(ddb_entry, &ha->ddb_list, list) {
-		if (memcmp(ddb_entry->iscsi_name, fw_ddb_entry->iscsi_name,
-			   ISCSI_NAME_SIZE) == 0) {
+		if ((memcmp(ddb_entry->iscsi_name, fw_ddb_entry->iscsi_name,
+			   ISCSI_NAME_SIZE) == 0) &&
+			(ddb_entry->tpgt ==
+				le32_to_cpu(fw_ddb_entry->tgt_portal_grp)) &&
+			(memcmp(ddb_entry->isid, fw_ddb_entry->isid,
+				sizeof(ddb_entry->isid)) == 0)) {
 			found++;
 			break;
 		}
@@ -443,6 +447,8 @@ int qla4xxx_update_ddb_entry(struct scsi_qla_host *ha,
 
 	ddb_entry->port = le16_to_cpu(fw_ddb_entry->port);
 	ddb_entry->tpgt = le32_to_cpu(fw_ddb_entry->tgt_portal_grp);
+	memcpy(ddb_entry->isid, fw_ddb_entry->isid, sizeof(ddb_entry->isid));
+
 	memcpy(&ddb_entry->iscsi_name[0], &fw_ddb_entry->iscsi_name[0],
 	       min(sizeof(ddb_entry->iscsi_name),
 		   sizeof(fw_ddb_entry->iscsi_name)));
diff --git a/drivers/scsi/qla4xxx/ql4_version.h b/drivers/scsi/qla4xxx/ql4_version.h
index 5c9041b..d186a18 100644
--- a/drivers/scsi/qla4xxx/ql4_version.h
+++ b/drivers/scsi/qla4xxx/ql4_version.h
@@ -5,5 +5,5 @@
  * See LICENSE.qla4xxx for copyright and licensing details.
  */
 
-#define QLA4XXX_DRIVER_VERSION	"5.01.00.00.05.03-k8"
+#define QLA4XXX_DRIVER_VERSION	"5.01.00.01.05.03-k9"