lib/iscsi: Update redirect portal of public portal group

iscsi_tgt_node_redirect() updates redirect portal of the initial
portal iin a primary portal group for the target node.

Check if the specified portal group is a public portal group and is
mapped to the target node first.

Then if the passed IP address-port pair is NULL, clear the current
redirect setting. Public portal group and private portal group are
clearly separated and redirect portal must be chosen from a private
portal group. Hence this clear method is intuitive and simple.

If the passed IP address-port pair is not NULL, check if they are
valid, and are not in the specified portal group. Then update a
redirect portal of the portal group map.

Finally, send asynchronous logout request to all corresponding
initiators.

Besides, change allocating pg_map from malloc to calloc to initialize
redirect portal.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I79d826663f4c3d5a117add286f133adeb1ce07f5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3222
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/iscsi/tgt_node.c

@@ -553,7 +553,7 @@ iscsi_tgt_node_add_pg_map(struct spdk_iscsi_tgt_node *target,
 		return NULL;
 	}
 
-	pg_map = malloc(sizeof(*pg_map));
+	pg_map = calloc(1, sizeof(*pg_map));
 	if (pg_map == NULL) {
 		return NULL;
 	}
@@ -857,6 +857,63 @@ invalid:
 	return -1;
 }
 
+int
+iscsi_tgt_node_redirect(struct spdk_iscsi_tgt_node *target, int pg_tag,
+			const char *host, const char *port)
+{
+	struct spdk_iscsi_portal_grp *pg;
+	struct spdk_iscsi_pg_map *pg_map;
+	struct sockaddr_storage sa;
+
+	if (target == NULL) {
+		return -EINVAL;
+	}
+
+	pg = iscsi_portal_grp_find_by_tag(pg_tag);
+	if (pg == NULL) {
+		SPDK_ERRLOG("Portal group %d is not found.\n", pg_tag);
+		return -EINVAL;
+	}
+
+	if (pg->is_private) {
+		SPDK_ERRLOG("Portal group %d is not public portal group.\n", pg_tag);
+		return -EINVAL;
+	}
+
+	pg_map = iscsi_tgt_node_find_pg_map(target, pg);
+	if (pg_map == NULL) {
+		SPDK_ERRLOG("Portal group %d is not mapped.\n", pg_tag);
+		return -EINVAL;
+	}
+
+	if (host == NULL && port == NULL) {
+		/* Clear redirect setting. */
+		memset(pg_map->redirect_host, 0, MAX_PORTAL_ADDR + 1);
+		memset(pg_map->redirect_port, 0, MAX_PORTAL_PORT + 1);
+	} else {
+		if (iscsi_parse_redirect_addr(&sa, host, port) != 0) {
+			SPDK_ERRLOG("IP address-port pair is not valid.\n");
+			return -EINVAL;
+		}
+
+		if (iscsi_portal_grp_find_portal_by_addr(pg, port, host) != NULL) {
+			SPDK_ERRLOG("IP address-port pair must be chosen from a "
+				    "different private portal group\n");
+			return -EINVAL;
+		}
+
+		snprintf(pg_map->redirect_host, MAX_PORTAL_ADDR + 1, "%s", host);
+		snprintf(pg_map->redirect_port, MAX_PORTAL_PORT + 1, "%s", port);
+	}
+
+	/* Terminate connections to this public portal group by asynchronous
+	 * logout message.
+	 */
+	iscsi_conns_request_logout(target, pg_tag);
+
+	return 0;
+}
+
 static int
 check_iscsi_name(const char *name)
 {

lib/iscsi/tgt_node.h

@@ -59,6 +59,8 @@ struct spdk_iscsi_pg_map {
 	struct spdk_iscsi_portal_grp *pg;
 	int num_ig_maps;
 	TAILQ_HEAD(, spdk_iscsi_ig_map) ig_map_head;
+	char redirect_host[MAX_PORTAL_ADDR + 1];
+	char redirect_port[MAX_PORTAL_PORT + 1];
 	TAILQ_ENTRY(spdk_iscsi_pg_map) tailq ;
 };
 
@@ -126,6 +128,8 @@ int iscsi_target_node_add_pg_ig_maps(struct spdk_iscsi_tgt_node *target,
 int iscsi_target_node_remove_pg_ig_maps(struct spdk_iscsi_tgt_node *target,
 					int *pg_tag_list, int *ig_tag_list,
 					uint16_t num_maps);
+int iscsi_tgt_node_redirect(struct spdk_iscsi_tgt_node *target, int pg_tag,
+			    const char *host, const char *port);
 
 bool iscsi_tgt_node_access(struct spdk_iscsi_conn *conn,
 			   struct spdk_iscsi_tgt_node *target, const char *iqn,