Message processing method and real-time stream protocol application layer gateway in home gateway

Abstract

The invention discloses a message processing method which comprises the following steps: a home gateway establishes an expectation connection according to media stream message receiving and transmitting ports supplied by a client, forbids the established expectation connection, and transmits the ports of the established expectation connection to a server for selecting; the home gateway starts thecorresponding expectation connection of the selected port of the server according to the selected port of the server and waits for the arrival of the data message; detecting and modifying the data message according to the expectation connection when a data message arrives the expectation connection; establishing a corresponding connection track CONNYRACK record of the data message; and deleting the expectation connection which supplies an establishing a basis to the CONNYRACK record. Correspondingly, the invention provides a real-time stream protocol application layer gateway in a home gateway, and therefore, the message processing method can establish more expectation connections with enable parameters and prevent the attack through the expectation connections by forbidding the expectation connections which are not used.

Description

technical field [0001] The present invention relates to the field of network security in home gateways, in particular to a message processing method and a Real Time Streaming Protocol (RTSP, Real Time Streaming Protocol) application layer gateway (ALG, Application Layer Gateway) in home gateways. Background technique [0002] At present, with the development of the network, there are more and more applications for multimedia transmission through the network, such as network cameras and network video playback. Then, for many users who use a home gateway to access the Internet, the home gateway used uses RTSP to communicate between the private network and the public network. Among them, users who use RTSP can open multiple transmission connections to the server, but if the user needs to send media streams from another server through one server, since RTSP needs to determine the port of the media stream and the Internet Protocol (IP, Internet Protocol) address, and at this tim...

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Problems solved by technology

[0003] However, another problem will arise at this time: if the server wants to switch to another server to deliver the media stream, the IP address needs to be negotiated at this time, and RTSP will provide many forms of ports during the negotiation process between the client and the server. For the server to choose, such as port 5009-5010, so it is possible to create multiple expected connections that will not be used in the future, and the attacker can construct a data packet that meets the requirements of the expected connection, and use the above-mentioned unused expected connection to establish with the LAN side PC connection, sending its constructed data packets to the home gateway, thus providing the conditions for the attack

At this time, if multiple LAN-side PCs do not accept the modified port, when multiple LAN-side PCs establish connections with the server together, the first PC to establish the desired connection does not need the Modifying the port can successfully establish the desired connection, but when the second and subsequent PCs use the same port as the port for sending and receiving media stream packets, the port will be modified by the home gateway, so if the PC does not accept the modified port as its media stream message sending and receiving port, the media stream delivered by the server cannot be played normally

At this time, multiple LAN-side PCs connected to a home gateway cannot use the same port.

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