Make it possible to set (via iscsi.conf(5)) and query (via iscsictl -v)

initiator iSCSI offload.  Pass maximum data segment size supported by
chosen offload module to iscsid(8), and make iscsid(8) not try to negotiate
anything larger than that.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation

3 files changed, 13 insertions, 5 deletions

diff --git a/usr.sbin/iscsid/iscsid.c b/usr.sbin/iscsid/iscsid.c
index a6feb6a..b879f59 100644
--- a/usr.sbin/iscsid/iscsid.c
+++ b/usr.sbin/iscsid/iscsid.c
@@ -152,7 +152,8 @@ resolve_addr(const struct connection *conn, const char *address,
 
 static struct connection *
 connection_new(unsigned int session_id, const uint8_t isid[8], uint16_t tsih,
-    const struct iscsi_session_conf *conf, int iscsi_fd)
+    const struct iscsi_session_conf *conf, const struct iscsi_session_limits
+    *limits, int iscsi_fd)
 {
 	struct connection *conn;
 	struct addrinfo *from_ai, *to_ai;
@@ -186,6 +187,7 @@ connection_new(unsigned int session_id, const uint8_t isid[8], uint16_t tsih,
 	 * XXX: Should we sanitize this somehow?
 	 */
 	memcpy(&conn->conn_conf, conf, sizeof(conn->conn_conf));
+	memcpy(&conn->conn_limits, limits, sizeof(conn->conn_limits));
 
 	from_addr = conn->conn_conf.isc_initiator_addr;
 	to_addr = conn->conn_conf.isc_target_addr;
@@ -443,7 +445,8 @@ handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int tim
 	}
 
 	conn = connection_new(request->idr_session_id, request->idr_isid,
-	    request->idr_tsih, &request->idr_conf, iscsi_fd);
+	    request->idr_tsih, &request->idr_conf, &request->idr_limits,
+	    iscsi_fd);
 	set_timeout(timeout);
 	capsicate(conn);
 	login(conn);
diff --git a/usr.sbin/iscsid/iscsid.h b/usr.sbin/iscsid/iscsid.h
index 9ad3325..448e9b7 100644
--- a/usr.sbin/iscsid/iscsid.h
+++ b/usr.sbin/iscsid/iscsid.h
@@ -51,6 +51,7 @@ struct connection {
 	int			conn_socket;
 	unsigned int		conn_session_id;
 	struct iscsi_session_conf	conn_conf;
+	struct iscsi_session_limits	conn_limits;
 	char			conn_target_alias[ISCSI_ADDR_LEN];
 	uint8_t			conn_isid[6];
 	uint16_t		conn_tsih;
diff --git a/usr.sbin/iscsid/login.c b/usr.sbin/iscsid/login.c
index 1338970..ed0b9bf 100644
--- a/usr.sbin/iscsid/login.c
+++ b/usr.sbin/iscsid/login.c
@@ -441,6 +441,10 @@ login_negotiate(struct connection *conn)
 	request = login_new_request(conn, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
 	request_keys = keys_new();
 
+	log_debugx("offload \"%s\" limits MaxRecvDataSegmentLength to %zd",
+	    conn->conn_conf.isc_offload,
+	    conn->conn_limits.isl_max_data_segment_length);
+
 	/*
 	 * The following keys are irrelevant for discovery sessions.
 	 */
@@ -456,9 +460,9 @@ login_negotiate(struct connection *conn)
 
 		keys_add(request_keys, "ImmediateData", "Yes");
 		keys_add_int(request_keys, "MaxBurstLength",
-		    2 * ISCSI_MAX_DATA_SEGMENT_LENGTH);
+		    2 * conn->conn_limits.isl_max_data_segment_length);
 		keys_add_int(request_keys, "FirstBurstLength",
-		    ISCSI_MAX_DATA_SEGMENT_LENGTH);
+		    conn->conn_limits.isl_max_data_segment_length);
 		keys_add(request_keys, "InitialR2T", "Yes");
 		keys_add(request_keys, "MaxOutstandingR2T", "1");
 	} else {
@@ -467,7 +471,7 @@ login_negotiate(struct connection *conn)
 	}
 
 	keys_add_int(request_keys, "MaxRecvDataSegmentLength",
-	    ISCSI_MAX_DATA_SEGMENT_LENGTH);
+	    conn->conn_limits.isl_max_data_segment_length);
 	keys_add(request_keys, "DefaultTime2Wait", "0");
 	keys_add(request_keys, "DefaultTime2Retain", "0");
 	keys_add(request_keys, "ErrorRecoveryLevel", "0");