iscsi-target: remove support for obsolete markers

Support for markers is currently broken because of a bug in
iscsi_enforce_integrity_rules(): the "IFMarkInt_Reject" and
"OFMarkInt_Reject" variables are always equal to 1 in
iscsi_enforce_integrity_rules().

Moreover, fixed interval markers keys (IFMarker, OFMarker, IFMarkInt
and OFMarkInt) are obsolete according to iSCSI RFC 7143:

>From http://tools.ietf.org/html/rfc7143#section-13.25:

   13.25.  Obsoleted Keys

   This document obsoletes the following keys defined in [RFC3720]:
   IFMarker, OFMarker, OFMarkInt, and IFMarkInt.  However, iSCSI
   implementations compliant to this document may still receive these
   obsoleted keys -- i.e., in a responder role -- in a text negotiation.

   When an IFMarker or OFMarker key is received, a compliant iSCSI
   implementation SHOULD respond with the constant "Reject" value.  The
   implementation MAY alternatively respond with a "No" value.

   However, the implementation MUST NOT respond with a "NotUnderstood"
   value for either of these keys.

   When an IFMarkInt or OFMarkInt key is received, a compliant iSCSI
   implementation MUST respond with the constant "Reject" value.  The
   implementation MUST NOT respond with a "NotUnderstood" value for
   either of these keys.

This patch disables markers by turning the corresponding parameters to
read-only. The default value of IFMarker and OFMarker remains "No" but
the user cannot change it to "Yes" anymore. The new value of IFMarkInt
and OFMarkInt is "Reject".

(Drop left-over iscsi_get_value_from_number_range + make configfs
 parameters attrs R/W nops - nab)

Signed-off-by: Christophe Vu-Brugier <cvubrugier@fastmail.fm>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 0 insertions, 53 deletions

diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index 959a14c9dd5d..210f6e4830e3 100644
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -956,56 +956,3 @@ void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn)
 
 	iscsit_handle_connection_cleanup(conn);
 }
-
-/*
- *	This is the simple function that makes the magic of
- *	sync and steering happen in the follow paradoxical order:
- *
- *	0) Receive conn->of_marker (bytes left until next OFMarker)
- *	   bytes into an offload buffer.  When we pass the exact number
- *	   of bytes in conn->of_marker, iscsit_dump_data_payload() and hence
- *	   rx_data() will automatically receive the identical u32 marker
- *	   values and store it in conn->of_marker_offset;
- *	1) Now conn->of_marker_offset will contain the offset to the start
- *	   of the next iSCSI PDU.  Dump these remaining bytes into another
- *	   offload buffer.
- *	2) We are done!
- *	   Next byte in the TCP stream will contain the next iSCSI PDU!
- *	   Cool Huh?!
- */
-int iscsit_recover_from_unknown_opcode(struct iscsi_conn *conn)
-{
-	/*
-	 * Make sure the remaining bytes to next maker is a sane value.
-	 */
-	if (conn->of_marker > (conn->conn_ops->OFMarkInt * 4)) {
-		pr_err("Remaining bytes to OFMarker: %u exceeds"
-			" OFMarkInt bytes: %u.\n", conn->of_marker,
-				conn->conn_ops->OFMarkInt * 4);
-		return -1;
-	}
-
-	pr_debug("Advancing %u bytes in TCP stream to get to the"
-			" next OFMarker.\n", conn->of_marker);
-
-	if (iscsit_dump_data_payload(conn, conn->of_marker, 0) < 0)
-		return -1;
-
-	/*
-	 * Make sure the offset marker we retrived is a valid value.
-	 */
-	if (conn->of_marker_offset > (ISCSI_HDR_LEN + (ISCSI_CRC_LEN * 2) +
-	    conn->conn_ops->MaxRecvDataSegmentLength)) {
-		pr_err("OfMarker offset value: %u exceeds limit.\n",
-			conn->of_marker_offset);
-		return -1;
-	}
-
-	pr_debug("Discarding %u bytes of TCP stream to get to the"
-			" next iSCSI Opcode.\n", conn->of_marker_offset);
-
-	if (iscsit_dump_data_payload(conn, conn->of_marker_offset, 0) < 0)
-		return -1;
-
-	return 0;
-}