MFC r271437:

Don't blindly assume the target agreed to transition to Full Feature Phase;
if we got a Login Response PDU without the "T" bit set, try again with
an empty request.  This fixes interoperability with COMSTAR.

Reviewed by:	mav
Tested by:	mav
Approved by:	re (kib)
Sponsored by:	The FreeBSD Foundation

1 files changed, 31 insertions, 9 deletions

diff --git a/usr.sbin/iscsid/login.c b/usr.sbin/iscsid/login.c
index 3391f90..1b8703c 100644
--- a/usr.sbin/iscsid/login.c
+++ b/usr.sbin/iscsid/login.c
@@ -574,7 +574,7 @@ login_negotiate(struct connection *conn)
 	struct pdu *request, *response;
 	struct keys *request_keys, *response_keys;
 	struct iscsi_bhs_login_response *bhslr;
-	int i;
+	int i, nrequests = 0;
 
 	log_debugx("beginning operational parameter negotiation");
 	request = login_new_request(conn, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
@@ -628,19 +628,41 @@ login_negotiate(struct connection *conn)
 		    response_keys->keys_names[i], response_keys->keys_values[i]);
 	}
 
-	bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;
-	if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0)
-		log_warnx("received final login response "
-		    "without the \"T\" flag");
-	else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE)
+	keys_delete(response_keys);
+	response_keys = NULL;
+
+	for (;;) {
+		bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;
+		if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0)
+			break;
+
+		nrequests++;
+		if (nrequests > 5) {
+			log_warnx("received login response "
+			    "without the \"T\" flag too many times; giving up");
+			break;
+		}
+
+		log_debugx("received login response "
+		    "without the \"T\" flag; sending another request");
+
+		pdu_delete(response);
+
+		request = login_new_request(conn,
+		    BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
+		pdu_send(request);
+		pdu_delete(request);
+
+		response = login_receive(conn);
+	}
+
+	if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE)
 		log_warnx("received final login response with wrong NSG 0x%x",
 		    login_nsg(response));
+	pdu_delete(response);
 
 	log_debugx("operational parameter negotiation done; "
 	    "transitioning to Full Feature phase");
-
-	keys_delete(response_keys);
-	pdu_delete(response);
 }
 
 static void