res_http_websocket: respond to CLOSE opcode

This ensures that Asterisk responds properly to frames received from a
client with opcode 8 (CLOSE) by echoing back the status code in its own
CLOSE frame.

Handling of the CLOSE opcode is moved up with the rest of the opcodes so
that unmasking gets applied. The payload is no longer returned to the
caller, but neither ARI nor the chan_sip nor pjsip made use of the
payload, which is a good thing since it was masked.

ASTERISK-28231 #close

Change-Id: Icb1b60205fc77ee970ddc91d1f545671781344cf

res/res_http_websocket.c

@@ -99,6 +99,7 @@ struct ast_websocket {
 	unsigned int close_sent:1;          /*!< Bit to indicate that the session close opcode has been sent and no further data will be sent */
 	struct websocket_client *client;    /*!< Client object when connected as a client websocket */
 	char session_id[AST_UUID_STR_LEN];  /*!< The identifier for the websocket session */
+	uint16_t close_status_code;         /*!< Status code sent in a CLOSE frame upon shutdown */
 };
 
 /*! \brief Hashing function for protocols */
@@ -173,7 +174,7 @@ static void session_destroy_fn(void *obj)
 	struct ast_websocket *session = obj;
 
 	if (session->stream) {
-		ast_websocket_close(session, 0);
+		ast_websocket_close(session, session->close_status_code);
 		if (session->stream) {
 			ast_iostream_close(session->stream);
 			session->stream = NULL;
@@ -578,7 +579,7 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 	*opcode = buf[0] & 0xf;
 	*payload_len = buf[1] & 0x7f;
 	if (*opcode == AST_WEBSOCKET_OPCODE_TEXT || *opcode == AST_WEBSOCKET_OPCODE_BINARY || *opcode == AST_WEBSOCKET_OPCODE_CONTINUATION ||
-	    *opcode == AST_WEBSOCKET_OPCODE_PING || *opcode == AST_WEBSOCKET_OPCODE_PONG) {
+	    *opcode == AST_WEBSOCKET_OPCODE_PING || *opcode == AST_WEBSOCKET_OPCODE_PONG  || *opcode == AST_WEBSOCKET_OPCODE_CLOSE) {
 		fin = (buf[0] >> 7) & 1;
 		mask_present = (buf[1] >> 7) & 1;
 
@@ -637,6 +638,16 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 			return 0;
 		}
 
+		/* Save the CLOSE status code which will be sent in our own CLOSE in the destructor */
+		if (*opcode == AST_WEBSOCKET_OPCODE_CLOSE) {
+			session->closing = 1;
+			if (*payload_len >= 2) {
+				session->close_status_code = ntohs(get_unaligned_uint16(*payload));
+			}
+			*payload_len = 0;
+			return 0;
+		}
+
 		if (*payload_len) {
 			if (!(new_payload = ast_realloc(session->payload, (session->payload_len + *payload_len)))) {
 				ast_log(LOG_WARNING, "Failed allocation: %p, %zu, %"PRIu64"\n",
@@ -676,28 +687,6 @@ int AST_OPTIONAL_API_NAME(ast_websocket_read)(struct ast_websocket *session, cha
 			*payload = session->payload;
 			session->payload_len = 0;
 		}
-	} else if (*opcode == AST_WEBSOCKET_OPCODE_CLOSE) {
-		session->closing = 1;
-
-		/* Make the payload available so the user can look at the reason code if they so desire */
-		if (!*payload_len) {
-			return 0;
-		}
-
-		if (!(new_payload = ast_realloc(session->payload, *payload_len))) {
-			ast_log(LOG_WARNING, "Failed allocation: %p, %"PRIu64"\n",
-					session->payload, *payload_len);
-			*payload_len = 0;
-			return -1;
-		}
-
-		session->payload = new_payload;
-		if (ws_safe_read(session, &buf[frame_size], *payload_len, opcode)) {
-			return -1;
-		}
-		memcpy(session->payload, &buf[frame_size], *payload_len);
-		*payload = session->payload;
-		frame_size += *payload_len;
 	} else {
 		ast_log(LOG_WARNING, "WebSocket unknown opcode %u\n", *opcode);
 		/* We received an opcode that we don't understand, the RFC states that 1003 is for a type of data that can't be accepted... opcodes