iscsi: Resolve iscsi_proto.h naming conflicts with drivers/target/iscsi

This patch renames the following iscsi_proto.h structures to avoid
namespace issues with drivers/target/iscsi/iscsi_target_core.h:

*) struct iscsi_cmd -> struct iscsi_scsi_req
*) struct iscsi_cmd_rsp -> struct iscsi_scsi_rsp
*) struct iscsi_login -> struct iscsi_login_req

This patch includes useful ISCSI_FLAG_LOGIN_[CURRENT,NEXT]_STAGE*,
and ISCSI_FLAG_SNACK_TYPE_* definitions used by iscsi_target_mod, and
fixes the incorrect definition of struct iscsi_snack to following
RFC-3720 Section 10.16. SNACK Request.

Also, this patch updates libiscsi, iSER, be2iscsi, and bn2xi to
use the updated structure definitions in a handful of locations.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
index dd0a52c..a9c9058 100644
--- a/include/scsi/iscsi_proto.h
+++ b/include/scsi/iscsi_proto.h
@@ -116,7 +116,7 @@
 #define ISCSI_CDB_SIZE			16
 
 /* iSCSI PDU Header */
-struct iscsi_cmd {
+struct iscsi_scsi_req {
 	uint8_t opcode;
 	uint8_t flags;
 	__be16 rsvd2;
@@ -161,7 +161,7 @@
 };
 
 /* SCSI Response Header */
-struct iscsi_cmd_rsp {
+struct iscsi_scsi_rsp {
 	uint8_t opcode;
 	uint8_t flags;
 	uint8_t response;
@@ -406,7 +406,7 @@
 };
 
 /* Login Header */
-struct iscsi_login {
+struct iscsi_login_req {
 	uint8_t opcode;
 	uint8_t flags;
 	uint8_t max_version;	/* Max. version supported */
@@ -427,7 +427,13 @@
 #define ISCSI_FLAG_LOGIN_TRANSIT		0x80
 #define ISCSI_FLAG_LOGIN_CONTINUE		0x40
 #define ISCSI_FLAG_LOGIN_CURRENT_STAGE_MASK	0x0C	/* 2 bits */
+#define ISCSI_FLAG_LOGIN_CURRENT_STAGE1		0x04
+#define ISCSI_FLAG_LOGIN_CURRENT_STAGE2		0x08
+#define ISCSI_FLAG_LOGIN_CURRENT_STAGE3		0x0C
 #define ISCSI_FLAG_LOGIN_NEXT_STAGE_MASK	0x03	/* 2 bits */
+#define ISCSI_FLAG_LOGIN_NEXT_STAGE1		0x01
+#define ISCSI_FLAG_LOGIN_NEXT_STAGE2		0x02
+#define ISCSI_FLAG_LOGIN_NEXT_STAGE3		0x03
 
 #define ISCSI_LOGIN_CURRENT_STAGE(flags) \
 	((flags & ISCSI_FLAG_LOGIN_CURRENT_STAGE_MASK) >> 2)
@@ -550,17 +556,25 @@
 struct iscsi_snack {
 	uint8_t opcode;
 	uint8_t flags;
-	uint8_t rsvd2[14];
+	uint8_t rsvd2[2];
+	uint8_t hlength;
+	uint8_t dlength[3];
+	uint8_t lun[8];
 	itt_t	 itt;
+	__be32  ttt;
+	uint8_t rsvd3[4];
+	__be32  exp_statsn;
+	uint8_t rsvd4[8];
 	__be32	begrun;
 	__be32	runlength;
-	__be32	exp_statsn;
-	__be32	rsvd3;
-	__be32	exp_datasn;
-	uint8_t rsvd6[8];
 };
 
 /* SNACK PDU flags */
+#define ISCSI_FLAG_SNACK_TYPE_DATA		0
+#define ISCSI_FLAG_SNACK_TYPE_R2T		0
+#define ISCSI_FLAG_SNACK_TYPE_STATUS		1
+#define ISCSI_FLAG_SNACK_TYPE_DATA_ACK		2
+#define ISCSI_FLAG_SNACK_TYPE_RDATA		3
 #define ISCSI_FLAG_SNACK_TYPE_MASK	0x0F	/* 4 bits */
 
 /* Reject Message Header */