charon-cmd: Make local host configurable

This allows preferring a particular address family (via 0.0.0.0 or ::)
or even a specific local address.

src/charon-cmd/cmd/cmd_connection.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Tobias Brunner
+ * Copyright (C) 2013-2026 Tobias Brunner
  * Copyright (C) 2013 Martin Willi
  *
  * Copyright (C) secunet Security Networks AG
@@ -102,6 +102,11 @@ struct private_cmd_connection_t {
 	 */
 	char *host;
 
+	/**
+	 * Hostname to connect from
+	 */
+	char *host_local;
+
 	/**
 	 * Server identity, or NULL to use host
 	 */
@@ -150,7 +155,7 @@ static peer_cfg_t* create_peer_cfg(private_cmd_connection_t *this)
 	peer_cfg_t *peer_cfg;
 	proposal_t *proposal;
 	ike_cfg_create_t ike = {
-		.local = "%any",
+		.local = this->host_local ?: "%any",
 		.remote = this->host,
 		.remote_port = IKEV2_UDP_PORT,
 		.fragmentation = FRAGMENTATION_YES,
@@ -502,6 +507,9 @@ METHOD(cmd_connection_t, handle, bool,
 		case CMD_OPT_HOST:
 			this->host = arg;
 			break;
+		case CMD_OPT_HOST_LOCAL:
+			this->host_local = arg;
+			break;
 		case CMD_OPT_REMOTE_IDENTITY:
 			this->server = arg;
 			break;

src/charon-cmd/cmd/cmd_options.c

@@ -31,6 +31,8 @@ cmd_option_t cmd_options[CMD_OPT_COUNT] = {
 	  "set the default log level (-1..4, default: 1)", {}},
 	{ CMD_OPT_HOST, "host", required_argument, "hostname",
 	  "DNS name or address to connect to", {}},
+	{ CMD_OPT_HOST_LOCAL, "host-local", required_argument, "hostname",
+	  "DNS name or address to connect from (default: %any)", {}},
 	{ CMD_OPT_IDENTITY, "identity", required_argument, "identity",
 	  "identity the client uses for the IKE exchange", {}},
 	{ CMD_OPT_EAP_IDENTITY, "eap-identity", required_argument, "eap-identity",

src/charon-cmd/cmd/cmd_options.h

@@ -34,6 +34,7 @@ enum cmd_option_type_t {
 	CMD_OPT_VERSION,
 	CMD_OPT_DEBUG,
 	CMD_OPT_HOST,
+	CMD_OPT_HOST_LOCAL,
 	CMD_OPT_IDENTITY,
 	CMD_OPT_EAP_IDENTITY,
 	CMD_OPT_XAUTH_USER,