[nrf fromtree] net: coap_client: handle observe requests as intended

The coap_client lib only handled "one-shot" requests properly. This
patch allows it to keep listening for additional responses to a request,
if the request was made with the CoAP OBSERVE option appended.

An API for canceling such requests is also added.

Signed-off-by: Benjamin Lindqvist <[email protected]>
(cherry picked from commit 0d14143)

Author: tautologyclub

include/zephyr/net/coap_client.h

@@ -137,6 +137,17 @@ int coap_client_init(struct coap_client *client, const char *info);
 int coap_client_req(struct coap_client *client, int sock, const struct sockaddr *addr,
 		    struct coap_client_request *req, struct coap_transmission_parameters *params);
 
+/**
+ * @brief Cancel all current requests.
+ *
+ * This is intended for canceling long-running requests (e.g. GETs with the OBSERVE option set)
+ * which has gone stale for some reason.
+ *
+ * @param client Client instance.
+ */
+void coap_client_cancel_requests(struct coap_client *client);
+
+
 /**
  * @}
  */

subsys/net/lib/coap/coap_client.c

@@ -811,10 +811,19 @@ static int handle_response(struct coap_client *client, const struct coap_packet
 	}
 fail:
 	client->response_ready = false;
-	internal_req->request_ongoing = false;
+	if (ret != 0 || !coap_request_is_observe(&internal_req->request)) {
+		internal_req->request_ongoing = false;
+	}
 	return ret;
 }
 
+void coap_client_cancel_requests(struct coap_client *client)
+{
+	for (int i = 0; i < ARRAY_SIZE(client->requests); i++) {
+		client->requests[i].request_ongoing = false;
+	}
+}
+
 void coap_client_recv(void *coap_cl, void *a, void *b)
 {
 	int ret;