From 4cb8aeb31a8cf47f6c61aaccb95bbbf47cbc2393 Mon Sep 17 00:00:00 2001 From: Max Romanov Date: Wed, 28 Oct 2020 00:01:46 +0300 Subject: Router: introducing the PORT_ACK message. The PORT_ACK message is the router's response to the application's NEW_PORT message. After receiving PORT_ACK, the application is safe to process requests using this port. This message avoids a racing condition when the application starts processing a request from the shared queue and sends REQ_HEADERS_ACK. The REQ_HEADERS_ACK message contains the application port ID as reply_port, which the router uses to send request data. When the application creates a new port, it immediately sends it to the main router thread. Because the request is processed outside the main thread, a racing condition can occur between the receipt of the new port in the main thread and the receipt of REQ_HEADERS_ACK in the worker router thread where the same port is specified as reply_port. --- src/nxt_port.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'src/nxt_port.h') diff --git a/src/nxt_port.h b/src/nxt_port.h index 3ac8c735..5ece3bfa 100644 --- a/src/nxt_port.h +++ b/src/nxt_port.h @@ -26,6 +26,7 @@ struct nxt_port_handlers_s { nxt_port_handler_t change_file; nxt_port_handler_t new_port; nxt_port_handler_t get_port; + nxt_port_handler_t port_ack; nxt_port_handler_t mmap; nxt_port_handler_t get_mmap; @@ -84,6 +85,7 @@ typedef enum { _NXT_PORT_MSG_CHANGE_FILE = nxt_port_handler_idx(change_file), _NXT_PORT_MSG_NEW_PORT = nxt_port_handler_idx(new_port), _NXT_PORT_MSG_GET_PORT = nxt_port_handler_idx(get_port), + _NXT_PORT_MSG_PORT_ACK = nxt_port_handler_idx(port_ack), _NXT_PORT_MSG_MMAP = nxt_port_handler_idx(mmap), _NXT_PORT_MSG_GET_MMAP = nxt_port_handler_idx(get_mmap), @@ -120,6 +122,7 @@ typedef enum { NXT_PORT_MSG_CHANGE_FILE = nxt_msg_last(_NXT_PORT_MSG_CHANGE_FILE), NXT_PORT_MSG_NEW_PORT = nxt_msg_last(_NXT_PORT_MSG_NEW_PORT), NXT_PORT_MSG_GET_PORT = nxt_msg_last(_NXT_PORT_MSG_GET_PORT), + NXT_PORT_MSG_PORT_ACK = nxt_msg_last(_NXT_PORT_MSG_PORT_ACK), NXT_PORT_MSG_MMAP = nxt_msg_last(_NXT_PORT_MSG_MMAP) | NXT_PORT_MSG_SYNC, NXT_PORT_MSG_GET_MMAP = nxt_msg_last(_NXT_PORT_MSG_GET_MMAP), -- cgit