Cache responses in proxy mode in case they come out of order to be able to successfully managed different subscribe variations

src/generator.c

@@ -117,6 +117,8 @@ struct proxy_instance {
 	int64_t share_id;
 
 	ckmsgq_t *passsends;	// passthrough sends
+
+	char_entry_t *recvd_lines; /* Linked list of unprocessed messages */
 };
 
 typedef struct proxy_instance proxy_instance_t;
@@ -490,40 +492,99 @@ static json_t *find_notify(json_t *val)
 	return ret;
 }
 
+/* Get stored line in the proxy linked list of messages if any exist or NULL */
+static char *cached_proxy_line(proxy_instance_t *proxi)
+{
+	char *buf = NULL;
+
+	if (proxi->recvd_lines) {
+		char_entry_t *char_t = proxi->recvd_lines;
+
+		DL_DELETE(proxi->recvd_lines, char_t);
+		buf = char_t->buf;
+		free(char_t);
+	}
+	return buf;
+}
+
+/* Get next line in the proxy linked list of messages or a new line from the
+ * connsock if there are none. */
+static char *next_proxy_line(connsock_t *cs, proxy_instance_t *proxi)
+{
+	char *buf = cached_proxy_line(proxi);
+
+	if (!buf && read_socket_line(cs, 5) > 0)
+		buf = strdup(cs->buf);
+	return buf;
+}
+
+/* For appending a line to the proxy recv list */
+static void append_proxy_line(proxy_instance_t *proxi, const char *buf)
+{
+	char_entry_t *char_t = ckalloc(sizeof(char_entry_t));
+	char_t->buf = strdup(buf);
+	DL_APPEND(proxi->recvd_lines, char_t);
+}
+
+/* Get a new line from the connsock and return a copy of it */
+static char *new_proxy_line(connsock_t *cs)
+{
+	char *buf = NULL;
+
+	if (read_socket_line(cs, 5) < 1)
+		goto out;
+	buf = strdup(cs->buf);
+out:
+	return buf;
+}
+
 static bool parse_subscribe(connsock_t *cs, proxy_instance_t *proxi)
 {
 	json_t *val = NULL, *res_val, *notify_val, *tmp;
+	bool parsed, ret = false;
+	int retries = 0, size;
 	const char *string;
-	bool ret = false;
-	char *old;
-	int size;
+	char *buf, *old;
 
-	size = read_socket_line(cs, 5);
-	if (size < 1) {
+retry:
+	parsed = true;
+	if (!(buf = new_proxy_line(cs))) {
 		LOGWARNING("Failed to receive line in parse_subscribe");
 		goto out;
 	}
-	LOGDEBUG("parse_subscribe received %s", cs->buf);
+	LOGDEBUG("parse_subscribe received %s", buf);
 	/* Ignore err_val here stored in &tmp */
-	val = json_msg_result(cs->buf, &res_val, &tmp);
+	val = json_msg_result(buf, &res_val, &tmp);
 	if (!val || !res_val) {
-		LOGWARNING("Failed to get a json result in parse_subscribe, got: %s", cs->buf);
-		goto out;
+		LOGINFO("Failed to get a json result in parse_subscribe, got: %s", buf);
+		parsed = false;
 	}
 	if (!json_is_array(res_val)) {
-		LOGWARNING("Result in parse_subscribe not an array");
-		goto out;
+		LOGINFO("Result in parse_subscribe not an array");
+		parsed = false;
 	}
 	size = json_array_size(res_val);
 	if (size < 3) {
-		LOGWARNING("Result in parse_subscribe array too small");
-		goto out;
+		LOGINFO("Result in parse_subscribe array too small");
+		parsed = false;
 	}
 	notify_val = find_notify(res_val);
 	if (!notify_val) {
-		LOGWARNING("Failed to find notify in parse_subscribe");
+		LOGINFO("Failed to find notify in parse_subscribe");
+		parsed = false;
+	}
+	if (!parsed) {
+		if (++retries < 3) {
+			/* We don't want this response so put it on the proxy
+			 * recvd list to be parsed later */
+			append_proxy_line(proxi, buf);
+			buf = NULL;
+			goto retry;
+		}
+		LOGWARNING("Failed to parse subscribe response in parse_subscribe");
 		goto out;
 	}
+
 	/* Free up old data in place if we are re-subscribing */
 	old = proxi->sessionid;
 	proxi->sessionid = NULL;
@@ -577,6 +638,7 @@ static bool parse_subscribe(connsock_t *cs, proxy_instance_t *proxi)
 out:
 	if (val)
 		json_decref(val);
+	free(buf);
 	return ret;
 }
 
@@ -962,6 +1024,7 @@ out:
 static bool auth_stratum(connsock_t *cs, proxy_instance_t *proxi)
 {
 	json_t *val = NULL, *res_val, *req, *err_val;
+	char *buf = NULL;
 	bool ret;
 
 	JSON_CPACK(req, "{s:i,s:s,s:[s,s]}",
@@ -979,25 +1042,24 @@ static bool auth_stratum(connsock_t *cs, proxy_instance_t *proxi)
 	/* Read and parse any extra methods sent. Anything left in the buffer
 	 * should be the response to our auth request. */
 	do {
-		int size;
-
-		size = read_socket_line(cs, 5);
-		if (size < 1) {
+		free(buf);
+		buf = next_proxy_line(cs, proxi);
+		if (!buf) {
 			LOGWARNING("Failed to receive line in auth_stratum");
 			ret = false;
 			goto out;
 		}
-		ret = parse_method(proxi, cs->buf);
+		ret = parse_method(proxi, buf);
 	} while (ret);
 
-	val = json_msg_result(cs->buf, &res_val, &err_val);
+	val = json_msg_result(buf, &res_val, &err_val);
 	if (!val) {
-		LOGWARNING("Failed to get a json result in auth_stratum, got: %s", cs->buf);
+		LOGWARNING("Failed to get a json result in auth_stratum, got: %s", buf);
 		goto out;
 	}
 
 	if (err_val && !json_is_null(err_val)) {
-		LOGWARNING("Failed to authorise in auth_stratum due to err_val, got: %s", cs->buf);
+		LOGWARNING("Failed to authorise in auth_stratum due to err_val, got: %s", buf);
 		goto out;
 	}
 	if (res_val) {
@@ -1014,6 +1076,15 @@ static bool auth_stratum(connsock_t *cs, proxy_instance_t *proxi)
 out:
 	if (val)
 		json_decref(val);
+	if (ret) {
+		/* Now parse any cached responses so there are none in the
+		 * queue and they can be managed one at a time from now on. */
+		do {
+			dealloc(buf);
+			buf = cached_proxy_line(proxi);
+			parse_method(proxi, buf);
+		} while (buf);
+	}
 	return ret;
 }