CN103179028B - The gateway device and its implementation of RTP data transmit-receives are carried out based on kernel - Google Patents

Abstract

The invention discloses a gateway device for transmitting and receiving RTP data based on a kernel, which belongs to a network device. The gateway device includes a driver module, and the driver module includes an RTP receiving submodule and an RTP reading submodule; the interface between the driver module and the RTP application program includes Create an interface, modify the interface and close the interface; the RTP receiving sub-module is connected to the socket of the kernel and the RTP reading sub-module respectively, and the RTP reading sub-module is connected to a DSP module; the driver module receives from the socket of the kernel through the RTP receiving sub-module Network RTP packets, and send the RTP packets to the system cache queue; the driver module reads the RTP packets from the system cache queue through the RTP reading sub-module, and sends the RTP packets to the DSP module. The beneficial effects of the present invention are: by directly processing RTP sending and receiving at the kernel layer, without frequently processing RTP packets through system calls, reducing the switching between the application layer and the kernel, and greatly reducing the forwarding delay of RTP , which enhances the robustness of the speech module.

Description

Gateway device for RTP data transmission and reception based on kernel and its implementation method

technical field

The invention relates to a network device, in particular to a gateway device for transmitting and receiving RTP data based on a kernel.

Background technique

Home gateways are used more and more in the field of broadband access. Chip manufacturers generally provide overall solutions, and most of the current solutions are Linux. For voice access, chip vendors only provide equipment vendors with DSP/SLIC APIs at the application layer. For media forwarding, chip vendors generally only provide methods for obtaining DSP modules from the application layer to generate media and receive media. The specific forwarding implementation is generally completed by the equipment manufacturer.

Considering cost and supply reasons, general equipment manufacturers need to implement the solutions of multiple chip manufacturers. Due to the different solutions of chip manufacturers, the realization of media forwarding will always cause duplication of work. In addition, the more important point is that since the RTP packet is generally 10ms/20ms during a call, the forwarding of RTP at the application layer will cause frequent switching between the kernel and the application layer, which will affect the efficiency of the system, especially in WiFi or Layer 3 When services such as forwarding are enabled, the voice quality will be seriously affected. The existing solution is to create a socket in the user layer and then listen to the socket through the polling of the select function, and then fetch the packets through the system call. In this way, when the voice is in circulation, many rtp packets are sent to and received from the dsp. The packet is sent to the network. The system call needs to fall into the kernel space from the user space. After processing, it needs to return to the user space. In addition to the actual time-consuming of the syscall service routine of the system, the trap/return process and the syscall handler (check the system call table, store/ Restoring the user site, etc.) also takes some time, and the sum of these times is the response speed of a syscall, so calling the syscall too frequently will lead to a decrease in response speed and a reduction in voice quality.

Contents of the invention

Aiming at the above-mentioned technical problems, the present invention provides a gateway device for transmitting and receiving RTP data based on the kernel, so as to reduce frequent switching between the kernel and the application layer and improve the operating efficiency of the system.

The specific technical scheme is as follows:

A gateway device for transmitting and receiving RTP data based on the kernel, wherein,

The gateway device includes a driver module, and the driver module includes an RTP receiving submodule and an RTP reading submodule; the interface between the driver module and the RTP application program includes creating an interface, modifying an interface, and closing an interface;

The RTP receiving submodule is respectively connected with the socket of the kernel and the RTP reading submodule, and the RTP reading submodule is connected with a DSP module;

The driver module receives the network RTP packet from the socket of the kernel through the RTP receiving submodule, and sends the RTP packet into the system cache queue; the driver module reads the submodule from the RTP packet through the RTP submodule Read the RTP packet from the system cache queue, and send the RTP packet to the DSP module.

The above-mentioned gateway device for transmitting and receiving RTP data based on the kernel, wherein,

The drive module also includes an RTP sending submodule, and the RTP sending submodule is connected to the DSP module;

The driver module receives the RTP payload from the DSP module through the RTP sending sub-module, encapsulates it into an IP packet format, and sends it out through the physical interface of the gateway device.

In the aforementioned gateway device for transmitting and receiving RTP data based on a kernel, the RTP receiving submodule and the RTP reading submodule operate synchronously through a data queue synchronization lock.

The above-mentioned gateway device for transmitting and receiving RTP data based on the kernel, wherein,

The creation interface is used to receive an instruction of the RTP application program to create an RTP flow, and set the RTP flow parameters; the modification interface is used to modify the RTP flow parameters; the shutdown interface is used to receive the RTP An instruction for the application to close the RTP stream and release system resources.

The above-mentioned gateway device for transmitting and receiving RTP data based on the kernel, wherein,

The parameters include DSP channel number, local port, local IP, remote port, remote IP and media direction.

In the above-mentioned gateway device for transmitting and receiving RTP data based on the kernel, the sending and receiving of the RTP data by the driver module is also applicable to the sending and receiving of RTCP data.

A method for transmitting and receiving RTP data based on the kernel, wherein the RTP data is transmitted and received through the above-mentioned gateway device, and the method specifically includes the following steps:

Step S1. Create an RTP stream by creating an interface of the RTP application program at the user layer, and create an RTP receiving kernel thread corresponding to the RTP stream, RTP reading kernel thread and RTP sending kernel thread in the system kernel;

Step S2. The RTP receiving kernel thread receives the RTP packet from the kernel socket, and sends it into the system cache queue;

Step S3. The RTP reading kernel thread reads the RTP packet from the system cache queue, and sends it to the message queue of the DSP module by using the interface of the DSP module.

The above-mentioned method for RTP data transmission and reception based on the kernel, wherein the method also includes:

Step S4. The RTP sending kernel thread receives the RTP payload from the DSP module, encapsulates it into an IP packet, and sends it out from the physical interface of the gateway device.

The above-mentioned method for RTP data sending and receiving based on the kernel, wherein, the step S2 also includes:

After the RTP receiving kernel thread of step S2.1 receives the RTP packet from the kernel socket, a data queue synchronization lock is obtained;

Step S2.2 The RTP receiving kernel thread adds the RTP packet to the cache queue, releases the available data packet semaphore, and simultaneously releases the data queue synchronization lock;

Said step S3 also includes:

Step S3.1 The RTP reading kernel thread keeps trying to obtain the packet semaphore, when the RTP reading kernel thread cannot obtain the packet semaphore, the RTP reading kernel thread sleeps, and is read by the system kernel Timer to wake up at regular intervals;

Step S3.2 When the RTP read kernel thread obtains the data packet semaphore, the RTP read kernel goes to get the data queue synchronization lock, and after obtaining the RTP packet from the cache queue, releases The data queue is synchronously locked.

The above-mentioned method for transmitting and receiving RTP data based on the kernel is also applicable to transmitting and receiving RTCP data.

The beneficial effects of this technical solution are: by directly processing RTP sending and receiving at the kernel layer, without frequently processing RTP packets through system calls, reducing the switching between the application layer and the kernel, and greatly reducing the RTP forwarding time delay, which enhances the robustness of the voice module.

Description of drawings

Fig. 1 is a kind of system structural diagram of the gateway device that carries out RTP data transmission and reception based on kernel in the embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for transmitting and receiving RTP data based on a kernel according to an embodiment of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

As shown in Figure 1, it is a system structure diagram of a gateway device for transmitting and receiving RTP data based on the kernel of the present invention, wherein,

The gateway device includes a driver module, and the driver module includes an RTP receiving submodule and an RTP reading submodule; the interface between the driver module and the RTP application program includes creating an interface, modifying an interface, and closing an interface; the RTP receiving submodule communicates with the socket and RTP of the kernel respectively The reading sub-module is connected, and the RTP reading sub-module is connected with a DSP module; the driver module receives the network RTP packet from the socket of the kernel through the RTP receiving sub-module, and sends the RTP packet to the system cache queue; the driver module reads through the RTP The sub-module reads the RTP packet from the system cache queue, and sends the RTP packet to the message queue of the DSP module, and the DSP chip and other devices decode and restore the data accordingly.

The driving module also includes an RTP sending sub-module, and the RTP sending sub-module is connected with the DSP module. The driver module receives the RTP payload from the DSP module through the RTP sending sub-module, encapsulates it into an IP packet format, and sends it out through the physical interface of the gateway device.

The technical principle of the present invention is: the operating space of an operating system such as Linux can be divided into a kernel space and a user space, which run in different levels and are logically isolated from each other. The present invention can transfer the sending and receiving of RTP data from the application layer to the kernel by directly calling service routines of syscalls such as sockets in the kernel, and at the same time unify the interface for RTP sending and receiving operations, so that RTP can be directly processed at the kernel layer Sending and receiving, without frequent system calls to process RTP packets, reducing the switching between the application layer and the kernel, greatly reducing the RTP forwarding delay, and enhancing the robustness of the voice module.

In the above-mentioned gateway device for transmitting and receiving RTP data based on the kernel, the RTP receiving submodule and the RTP reading submodule operate synchronously through the data queue synchronization lock. When the module is initialized, a data queue synchronization lock and an available data packet synchronization lock are created. When the receiving thread receives the RTP packet, it takes the data queue synchronization lock, then adds the received packet to the cache data queue, and then releases the available data. Packet semaphore, and then release the data queue synchronization lock. At the same time, the thread that sends packets to the DSP will continue to get the available data packet semaphore. If it cannot get it, the process sleeps. If it gets the available data packet semaphore, it will go to obtain the data queue synchronization lock, and then go to cache the packets in the data queue. , and finally release the data queue synchronization lock.

Create an interface to receive an instruction from an RTP application to create an RTP stream and set RTP stream parameters. This interface also needs to return an internal handle; modify the interface to modify RTP stream parameters; close the interface to receive an RTP application to close the RTP stream instructions and release system resources. Based on the above technical solution, the parameters include DSP channel number, local port, local IP, remote port, remote IP and media direction. According to the judgment of the direction passed down from the user layer, it is decided whether to send and receive data packets and interact with the DSP. In a specific embodiment, sockets and kernel threads are created abstractly by creating iplines (ip streams) at the user layer. Each ip stream corresponds to an ip stream context (ipline context), which includes socket, dsp channel, localip, parameters such as remoteip, ipline direction, and thread descriptor. Each ip flow has a kernel thread corresponding to it, and each kernel thread serves the corresponding ip flow. When the RTP payload is received from the DSP, it is sent to the network through the socket corresponding to the DSP channel in the ipline context.

The above-mentioned transmission and reception of RTP data by the driver module is also applicable to the transmission and reception of RTCP data.

In some applications, the RTP module is required to provide the function of receiving RFC2833 event packets, and the gateway device for RTP data transmission and reception based on the kernel of the present invention also provides this function.

As shown in Figure 2, it is a schematic flow diagram of the method for RTP data transmission and reception based on the kernel. By using the above-mentioned gateway device for RTP data transmission and reception, the method specifically includes the following steps:

Step S1. Create an RTP flow by creating an interface of the RTP application program at the user layer, and create an RTP receiving kernel thread corresponding to the RTP flow, RTP reading kernel thread and RTP sending kernel thread in the system kernel;

Step S2. The RTP receiving kernel thread receives the RTP packet from the kernel socket, and sends it into the system cache queue;

Step S3.RTP reads the kernel thread to read the RTP packet from the system cache queue, and utilizes the interface of the DSP module to send it to the message queue of the DSP module;

Step S4. The RTP sending kernel thread receives the RTP payload from the DSP module, encapsulates it into an IP packet, and sends it out from the physical interface of the gateway device.

In step S2, the following steps are also specifically included:

Step S2.1 After the RTP receiving kernel thread receives the RTP packet from the kernel socket, a data queue synchronization lock is obtained;

Step S2.2 The RTP receiving kernel thread adds the RTP packet to the cache queue, releases the available data packet semaphore, and simultaneously releases the data queue synchronization lock;

In step S3, the following steps are also specifically included:

Step S3.1 The RTP read kernel thread continuously tries to obtain the packet semaphore. When the RTP read kernel thread cannot obtain the packet semaphore, the RTP read kernel thread sleeps and is woken up regularly by the timer of the system kernel; the wake-up interval Set to 10ms.

Step S3.2 When the RTP reading kernel thread obtains the data packet semaphore, the RTP reading kernel will acquire the data queue synchronization lock, and release the data queue synchronization lock after obtaining the RTP packet from the buffer queue.

The above method for sending and receiving RTP data is also applicable to sending and receiving RTCP data.

The above are only preferred embodiments of the present invention, and are not intended to limit the implementation and protection scope of the present invention. For those skilled in the art, they should be able to realize the equivalent replacement and The solutions obtained by obvious changes shall all be included in the protection scope of the present invention.

Claims (8)

1. the gateway device of RTP data transmit-receives is carried out based on kernel, it is characterised in that

The gateway device includes a drive module, and the drive module includes RTP receiving submodules and RTP reads submodule Block；The interface of the drive module and RTP application programs includes creating interface, modification interface and down interface；

The RTP receiving submodules are connected with the socket of the kernel and the RTP reading submodules respectively, and the RTP is read Submodule is taken to be connected with a DSP module；The RTP receiving submodules and the RTP reading submodules pass through data queue synchronization Lock simultaneously operating；

The drive module receives network RTP bags by the RTP receiving submodules from the socket of the kernel, and by institute State RTP bags and be sent into system cache queue；The drive module is by the RTP reading submodules from the system cache queue The RTP bags are read, and the RTP bags are sent to the DSP module.

2. the gateway device of RTP data transmit-receives is carried out based on kernel as claimed in claim 1, it is characterised in that

The drive module also includes RTP sending submodules, and the RTP sending submodules are connected with the DSP module；

The drive module receives RTP payloads by the RTP sending submodules from the DSP module, is packaged into IP bag forms, And it is sent out by the physical interface of the gateway device.

3. the gateway device of RTP data transmit-receives is carried out based on kernel as claimed in claim 1, it is characterised in that

The instruction for creating interface and being used to receive one rtp streaming of the RTP application programs establishment, and set the rtp streaming to join Number；The modification interface is used to change the rtp streaming parameter；The down interface is used to receive the RTP closing application programs The instruction of the rtp streaming, and free system resources.

4. the gateway device of RTP data transmit-receives is carried out based on kernel as claimed in claim 3, it is characterised in that

The parameter includes DSP channel numbers, local port, local IP, remote port, far-end IP and media direction.

5. the gateway device that RTP data transmit-receives are carried out based on kernel as described in claim 1 to any one of claim 4, its It is characterised by, transmitting-receiving of the drive module to the RTP data is equally applicable to the transmitting-receiving to RTCP data.

6. the method for RTP data transmit-receives is carried out based on kernel, it is characterised in that pass through any one of such as above-mentioned claim 1 to 5 institute The gateway device stated carries out RTP data transmit-receives, and methods described specifically comprises the following steps：

Establishment interfaces of the step S1. in client layer by the RTP application programs, a rtp streaming is created, and created in system kernel Build RTP corresponding with the rtp streaming and receive kernel thread, RTP reading kernel threads and RTP transmission kernel threads；

RTP described in step S2. receives kernel thread and RTP bags is received from kernel socket, and is sent to system cache queue； Also include in the step S2：

After RTP receptions kernel thread receives RTP bags from kernel socket described in step S2.1, a data queue synchronization is obtained Lock；

RTP described in step S2.2 receives kernel thread and the RTP bags is added into buffer queue, and discharges data available bag signal Amount, while discharge the data queue synchronization lock；

RTP described in step S3. reads kernel thread and the RTP bags is read from the system cache queue, and utilizes DSP module Interface, be sent in the message queue of the DSP module；Also include in the step S3：

RTP described in step S3.1 reads kernel thread and continuously attempts to obtain data packet signal amount, when the RTP reads kernel thread The data packet signal amount can not be obtained, the RTP reads kernel thread sleep, and is called out by the timer timing of system kernel Wake up；

Step S3.2 obtains the data packet signal amount when the RTP reads kernel thread, and the RTP reads kernel and just goes to take institute Data queue synchronization lock is stated, and after RTP bags are obtained from the buffer queue, discharges the data queue synchronization lock.

7. the method for RTP data transmit-receives is carried out based on kernel as claimed in claim 6, it is characterised in that methods described is also wrapped Include：

RTP described in step S4. sends kernel thread and receives the RTP payloads from the DSP module, and is packaged into IP packet forms, Sent from the physical interface of the gateway device.

8. the method that RTP data transmit-receives are carried out based on kernel as described in claim 6 to any one of claim 7, same suitable For the transmitting-receiving to RTCP data.