ss: mqtt: add will and other sundries to policy

Replace the hacked-in constants with policy entries for sundry
MQTT features, and add to the policy readme.

include/libwebsockets/lws-secure-streams-policy.h

@@ -211,7 +211,16 @@ typedef struct lws_ss_policy {
 		struct {
 			const char	*topic;	    /* stream sends on this topic */
 			const char	*subscribe; /* stream subscribes to this topic */
+
+			const char	*will_topic;
+			const char	*will_message;
+
+			uint16_t	keep_alive;
 			uint8_t		qos;
+			uint8_t		clean_start;
+			uint8_t		will_qos;
+			uint8_t		will_retain;
+
 		} mqtt;
 
 		/* details for non-http related protocols... */

lib/secure-streams/README.md

@@ -292,6 +292,55 @@ Set the topic this streamtype subscribes to
 
 Set the QOS level for this streamtype
 
+### `mqtt_keep_alive`
+
+16-bit number representing MQTT keep alive for the stream.
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
+### `mqtt_clean_start`
+
+Set to true if the connection should use MQTT's "clean start" feature.
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
+### `mqtt_will_topic`
+
+Set the topic of the connection's will message, if any (there is none by default).
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
+### `mqtt_will_message`
+
+Set the content of the connect's will message, if any (there is none by default).
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
+### `mqtt_will_qos`
+
+Set the QoS of the will message, if any (there is none by default).
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
+### `mqtt_will_retain`
+
+Set to true if the connection should use MQTT's "will retain" feature, if there
+is a will message (there is none by default).
+
+This is applied at connection time... where different streams may bind to the
+same underlying MQTT connection, all the streams should have an identical
+setting for this.
+
 ## Loading and using updated remote policy
 
 If the default, hardcoded policy includes a streamtype `fetch_policy`,

lib/secure-streams/policy.c

@@ -85,6 +85,12 @@ static const char * const lejp_tokens_policy[] = {
 	"s[].*.mqtt_topic",
 	"s[].*.mqtt_subscribe",
 	"s[].*.mqtt_qos",
+	"s[].*.mqtt_keep_alive",
+	"s[].*.mqtt_clean_start",
+	"s[].*.mqtt_will_topic",
+	"s[].*.mqtt_will_message",
+	"s[].*.mqtt_will_qos",
+	"s[].*.mqtt_will_retain",
 	"s[].*",
 };
 
@@ -142,6 +148,12 @@ typedef enum {
 	LSSPPT_MQTT_TOPIC,
 	LSSPPT_MQTT_SUBSCRIBE,
 	LSSPPT_MQTT_QOS,
+	LSSPPT_MQTT_KEEPALIVE,
+	LSSPPT_MQTT_CLEAN_START,
+	LSSPPT_MQTT_WILL_TOPIC,
+	LSSPPT_MQTT_WILL_MESSAGE,
+	LSSPPT_MQTT_WILL_QOS,
+	LSSPPT_MQTT_WILL_RETAIN,
 	LSSPPT_STREAMTYPES
 } policy_token_t;
 
@@ -657,6 +669,30 @@ lws_ss_policy_parser_cb(struct lejp_ctx *ctx, char reason)
 		a->curr[LTY_POLICY].p->u.mqtt.qos = atoi(ctx->buf);
 		break;
 
+	case LSSPPT_MQTT_KEEPALIVE:
+		a->curr[LTY_POLICY].p->u.mqtt.keep_alive = atoi(ctx->buf);
+		break;
+
+	case LSSPPT_MQTT_CLEAN_START:
+		a->curr[LTY_POLICY].p->u.mqtt.clean_start =
+						reason == LEJPCB_VAL_TRUE;
+		break;
+	case LSSPPT_MQTT_WILL_TOPIC:
+		pp = (char **)&a->curr[LTY_POLICY].p->u.mqtt.will_topic;
+		goto string2;
+
+	case LSSPPT_MQTT_WILL_MESSAGE:
+		pp = (char **)&a->curr[LTY_POLICY].p->u.mqtt.will_message;
+		goto string2;
+
+	case LSSPPT_MQTT_WILL_QOS:
+		a->curr[LTY_POLICY].p->u.mqtt.will_qos = atoi(ctx->buf);
+		break;
+	case LSSPPT_MQTT_WILL_RETAIN:
+		a->curr[LTY_POLICY].p->u.mqtt.will_retain =
+						reason == LEJPCB_VAL_TRUE;
+		break;
+
 	case LSSPPT_PROTOCOL:
 		a->curr[LTY_POLICY].p->protocol = 0xff;
 		for (n = 0; n < (int)LWS_ARRAY_SIZE(protonames); n++)

lib/secure-streams/protocols/ss-mqtt.c

@@ -204,12 +204,12 @@ secstream_connect_munge_mqtt(lws_ss_handle_t *h, char *buf, size_t len,
 	memset(&ct->ccp, 0, sizeof(ct->ccp));
 
 	ct->ccp.client_id		= "lwsMqttClient";
-	ct->ccp.keep_alive		= 60;
-	ct->ccp.clean_start		= 1;
-	ct->ccp.will_param.topic	= "good/bye";
-	ct->ccp.will_param.message	= "sign-off";
-	ct->ccp.will_param.qos		= 0;
-	ct->ccp.will_param.retain	= 0;
+	ct->ccp.keep_alive		= h->policy->u.mqtt.keep_alive;
+	ct->ccp.clean_start		= h->policy->u.mqtt.clean_start;
+	ct->ccp.will_param.topic	= h->policy->u.mqtt.will_topic;
+	ct->ccp.will_param.message	= h->policy->u.mqtt.will_message;
+	ct->ccp.will_param.qos		= h->policy->u.mqtt.will_qos;
+	ct->ccp.will_param.retain	= h->policy->u.mqtt.will_retain;
 
 	lwsl_notice("%s\n", __func__);