lib/iscsi: Add iscsi_target_node_request_logout RPC

For the login redirection feature, the current implementation works
only if a portal is redirected from an initial portal to a redirect
portal. However, the login redirection feature should work even if a
portal is redirected from one redirect portal to another redirect
portal.

A public portal group knows only a redirect portal and does not know
the portal group of the redirect portal.

Moreover, it is very likely that an initial portal and a redirect portal
exist in different SPDK iSCSI target applications.

To cover all these concerns, add an new iscsi_target_node_request_logout
RPC to request connections whose portal group tag match for the target
node.

To cover potential use cases, make the second parameter portal group
tag optional.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I612672490722fb22fd4eba055998b7408ab84ca5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3780
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

doc/jsonrpc.md

@@ -4153,6 +4153,43 @@ Example response:
 }
 ~~~
 
+## iscsi_target_node_request_logout method {#rpc_iscsi_target_node_request_logout}
+
+For the target node, request connections whose portal group tag match to logout,
+or request all connections to logout if portal group tag is omitted.
+
+### Parameters
+
+Name                        | Optional | Type    | Description
+--------------------------- | -------- | --------| -----------
+name                        | Required | string  | Target node name (ASCII)
+pg_tag                      | Optional | number  | Existing portal group tag
+
+### Example
+
+Example request:
+
+~~~
+{
+  "params": {
+    "name": "iqn.2016-06.io.spdk:target1",
+    "pg_tag": 1
+  },
+  "jsonrpc": "2.0",
+  "method": "iscsi_target_node_request_logout",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
 
 # NVMe-oF Target {#jsonrpc_components_nvmf_tgt}
 

lib/iscsi/iscsi_rpc.c

@@ -1218,6 +1218,65 @@ rpc_iscsi_target_node_set_redirect(struct spdk_jsonrpc_request *request,
 SPDK_RPC_REGISTER("iscsi_target_node_set_redirect", rpc_iscsi_target_node_set_redirect,
 		  SPDK_RPC_RUNTIME)
 
+struct rpc_target_logout {
+	char *name;
+	int32_t pg_tag;
+};
+
+static void
+free_rpc_target_logout(struct rpc_target_logout *req)
+{
+	free(req->name);
+}
+
+static const struct spdk_json_object_decoder rpc_target_logout_decoders[] = {
+	{"name", offsetof(struct rpc_target_logout, name), spdk_json_decode_string},
+	{"pg_tag", offsetof(struct rpc_target_logout, pg_tag), spdk_json_decode_int32, true},
+};
+
+static void
+rpc_iscsi_target_node_request_logout(struct spdk_jsonrpc_request *request,
+				     const struct spdk_json_val *params)
+{
+	struct rpc_target_logout req = {};
+	struct spdk_iscsi_tgt_node *target;
+	struct spdk_json_write_ctx *w;
+
+	/* If pg_tag is omitted, request all connections to the specified target
+	 * to logout.
+	 */
+	req.pg_tag = -1;
+
+	if (spdk_json_decode_object(params, rpc_target_logout_decoders,
+				    SPDK_COUNTOF(rpc_target_logout_decoders),
+				    &req)) {
+		SPDK_ERRLOG("spdk_json_decode_object failed\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "Invalid parameters");
+		free_rpc_target_logout(&req);
+		return;
+	}
+
+	target = iscsi_find_tgt_node(req.name);
+	if (target == NULL) {
+		SPDK_ERRLOG("target %s is not found\n", req.name);
+		spdk_jsonrpc_send_error_response_fmt(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						     "Target %s is not found", req.name);
+		free_rpc_target_logout(&req);
+		return;
+	}
+
+	iscsi_conns_request_logout(target, req.pg_tag);
+
+	free_rpc_target_logout(&req);
+
+	w = spdk_jsonrpc_begin_result(request);
+	spdk_json_write_bool(w, true);
+	spdk_jsonrpc_end_result(request, w);
+}
+SPDK_RPC_REGISTER("iscsi_target_node_request_logout", rpc_iscsi_target_node_request_logout,
+		  SPDK_RPC_RUNTIME)
+
 static void
 rpc_iscsi_get_options(struct spdk_jsonrpc_request *request,
 		      const struct spdk_json_val *params)

scripts/rpc.py

@@ -1127,6 +1127,19 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
     p.add_argument('-p', '--redirect_port', help='Numeric TCP port for redirect portal', required=False)
     p.set_defaults(func=iscsi_target_node_set_redirect)
 
+    def iscsi_target_node_request_logout(args):
+        rpc.iscsi.iscsi_target_node_request_logout(
+            args.client,
+            name=args.name,
+            pg_tag=args.pg_tag)
+
+    p = subparsers.add_parser('iscsi_target_node_request_logout',
+                              help="""For the target node, request connections whose portal group tag
+    match to logout, or request all connections if portal group tag is omitted.""")
+    p.add_argument('name', help='Target node name (ASCII)')
+    p.add_argument('-t', '--pg-tag', help='Portal group tag (unique, integer > 0)', type=int, required=False)
+    p.set_defaults(func=iscsi_target_node_request_logout)
+
     def iscsi_create_portal_group(args):
         portals = []
         for p in args.portal_list.strip().split(' '):

scripts/rpc/iscsi.py

@@ -398,6 +398,23 @@ def iscsi_target_node_set_redirect(client, name, pg_tag, redirect_host, redirect
     return client.call('iscsi_target_node_set_redirect', params)
 
 
+def iscsi_target_node_request_logout(client, name, pg_tag):
+    """Request connections to the target node to logout.
+
+    Args:
+        name: Target node name (ASCII)
+        pg_tag: Portal group tag (unique, integer > 0) (optional)
+
+    Returns:
+        True or False
+    """
+    params = {'name': name}
+
+    if pg_tag:
+        params['pg_tag'] = pg_tag
+    return client.call('iscsi_target_node_request_logout', params)
+
+
 @deprecated_alias('add_portal_group')
 def iscsi_create_portal_group(client, portals, tag, private):
     """Add a portal group.