CN111726201A - A solution for AIRT-ROS virtual network card packet loss - Google Patents

Abstract

The invention discloses a solution for packet loss of an AIRT-ROS virtual network card, which comprises the following steps: when an application program sends a data packet to a virtual network card through an AIRT-ROS, when a receiving queue of the virtual network card exceeds a maximum transmission unit value, a flag bit is set and upper-layer application is informed to slow down the sending speed; when the virtual network card sends a data packet to an application program through the AIRT-ROS and a sending queue of the virtual network card exceeds a maximum transmission unit value, setting a flag bit and informing an upper layer application to slow down the sending speed; the invention has the advantages that: by setting the flag bit and informing the upper layer application or the remote application to adjust the sending speed, the problem of packet loss caused by inconsistent sending speeds of the upper layer application and the virtual network card is relieved.

Description

A solution for AIRT-ROS virtual network card packet loss

technical field

The invention relates to the field of packet loss of a virtual network card, and more particularly to a solution method for packet loss of an AIRT-ROS virtual network card.

Background technique

At present, most virtual network cards lose data packets can be divided into the following categories: host connection failures include disconnection between the host and the virtual connection (virtual connection), the host cannot directly connect through VIC (virtual Internet Connection, virtual Internet connection) or SSH (Secure Shell, Secure Protocol Shell) connection, virtual machine network loss after failover/failback. Packet loss caused by kernel or driver faults during vSwitch switching, including network blockage of some virtual machines, or network blockage of all virtual machines and host management ports. VNIC packet loss scenarios may include: when the virtual NIC fails, the upper-layer application does not know the status of the virtual NIC and still sends packets normally, resulting in packet loss; after the host fails, the upper-layer application defaults to the virtual NIC already sent and fails to detect Whether the data packet is actually sent successfully; the upper-layer application packet transmission rate exceeds the transmission rate of the virtual NIC driver, the virtual NIC reports the packet loss to the operating system, and then the operating system notifies the upper-layer application that the packet has been lost, and the upper-layer application makes corresponding adjustments. The entire message chain Some packets have been lost in the process of transmitting packet loss messages.

By analyzing the above phenomena, the main reasons for the packet loss of the virtual network card are the loss of data packets caused by the failure of the virtual network card or the host, and the fact that the forwarding capability of the virtual network card cannot meet the rate at which the upper-layer application sends and receives data packets. The sending and receiving packet rates of the virtual network card and the upper-layer application are not synchronized.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention lies in the problem of packet loss caused by asynchronous transmission and reception of data packet rates between the virtual network card and the upper-layer application program in the prior art.

The present invention solves the above technical problems through the following technical solutions: a solution method for AIRT-ROS virtual network card packet loss, the method includes:

When the application sends data packets to the virtual network card through AIRT-ROS (Artificial Intelligence Real Time-Robot Operating System), when the receiving queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified Slow down the sending speed; when the virtual network card sends data packets to the application through AIRT-ROS, when the sending queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified to slow down the sending speed.

Preferably, the AIRT-ROS is a multi-core dual operating system based on AMP architecture, one operating system is Linux, and the other operating system is RTERS real-time operating system, the AIRT-ROS includes a Linux kernel and an RTERS kernel, the Linux The kernel includes a robot operating system, a first hypertext transfer protocol, a file transfer protocol, and a first local advanced programmable interrupt controller, the RTERS kernel includes a robot real-time operating system, a second hypertext transfer protocol, and a second local advanced programmable interrupt controller Interrupt controller, the Linux kernel and the RTERS kernel are connected through an IPI interface, the robot operating system and the robot real-time operating system are virtually connected through a virtual switch, and the first local advanced programmable interrupt controller is connected through the first local advanced programmable interrupt controller. An I/O advanced programmable interrupt controller is connected to the non-real-time device and the virtual network card, the second local advanced programmable interrupt controller is connected to the real-time device through the second I/O advanced programmable interrupt controller, and the virtual network card is connected to the real-time device through the AIRT- ROS sends data packets to the application, or the virtual network card receives the data packets sent by the application through AIRT-ROS.

Preferably, the driver of the virtual network card is divided into a four-layer structure, namely a network protocol interface layer, a network device interface layer, a network driver interface layer, and a device media layer. By setting hooks in the network protocol interface layer and the network driver interface layer The function, which pre-determines the status of the receiving queue or the sending queue of the virtual network card, and notifies the upper-layer application to control the transmission packet rate.

Compared with the prior art, the present invention has the following advantages:

(1) In order to solve the packet loss problem of the virtual network card, the present invention proposes an AIRT-ROS virtual network card packet loss solution. By setting hook functions in the network protocol interface layer and the network driver interface layer, the state of the sending queue or Receive the status of the queue, set the flag bit and notify the upper-layer application or the remote application to adjust the sending speed, so as to alleviate the packet loss caused by the inconsistent sending speed between the upper-layer application and the virtual network card.

(2) Provide a multi-core dual operating system AIRT-ROS based on the AMP architecture. One of the operating systems of AIRT-ROS is Linux, and the other operating system is the RTERS real-time operating system. The Linux and RTERS operating systems respectively execute non-real-time processes and Real-time process; respond to non-real-time device interrupt and real-time device interrupt respectively; support communication between non-real-time process and real-time process; integrate many Linux drivers, which greatly reduces the workload of driving general external devices.

Description of drawings

1 is an architecture diagram of a virtual network card of an AIRT-ROS virtual network card packet loss solution provided by an embodiment of the present invention;

2 is a flowchart of a virtual network card receiving message driver segment of an AIRT-ROS virtual network card packet loss solution provided by an embodiment of the present invention;

3 is a flowchart of a protocol stack stage of a virtual network card receiving a packet of an AIRT-ROS virtual network card packet loss solution provided by an embodiment of the present invention;

4 is a flowchart of a virtual network card sending data packets of a solution method for AIRT-ROS virtual network card packet loss provided by an embodiment of the present invention;

FIG. 5 is an architecture diagram of AIRT-ROS according to an AIRT-ROS virtual network card packet loss solution provided by an embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following implementation. example.

The AIRT-ROS virtual network card packet loss solution of the present invention respectively includes a packet loss solution in the process of sending data packets by the virtual network card and a packet loss solution in the process of receiving data packets by the virtual network card, which are described in detail below through examples.

An AIRT-ROS virtual network card packet loss solution, the method includes:

When the application sends data packets to the virtual network card through AIRT-ROS (Artificial Intelligence Real Time-Robot Operating System), when the receiving queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified Slow down the sending speed; specifically, as shown in Figure 1, it is the architecture diagram of the virtual network card, and the driver of the virtual network card is divided into four-layer structure, namely the network protocol interface layer, the network device interface layer, the network driver interface layer, The device media layer, by setting hook functions in the network protocol interface layer and the network driver interface layer, pre-determines the status of the receiving queue of the virtual network card, and notifies the upper-layer application to control the transmission rate of the message. According to the flow direction of network packets, the hook function is executed before the packet is routed, the hook function is executed before the packet is transferred to another network interface, the hook function is executed before the packet flows out, and the inflowing local packet is executed after routing. The hook function and the hook function are executed before the outgoing routing of the local packet, so as to pre-determine whether the receiving and sending rates of the virtual network card can meet the requirements of the upper-layer application during the entire data transmission process. After the hook function is processed, it will return one of the following: continue normal packet processing, discard the packet, process the packet by the hook function, do not continue to transmit, queue the packet, usually handed over to the user program Process and call the hook function again to inform the AIRT-ROS core code of the processing result, so as to take corresponding actions on the message.

The process of receiving data packets by the virtual network card is divided into two stages. The first stage receives the message driver segment process, and the second stage receives the message protocol stack stage process. First, the process of receiving the message driver segment is introduced. As shown in Figure 2, the flow chart of the driver segment for receiving the message for the virtual network card, the data packet arrives, the interrupt service routine is started, the receiving function is AIRT_rx(), the buffer data structure is allocated and generated, that is, the skb structure, and then the public message is called. The receiving function puts the buffered data structure into the CPU network data queue, sets the soft interrupt, calls the hook function to judge whether the message rate exceeds the maximum transmission unit value, and sets the flag bit to wait for the CPU to schedule.

The second stage receives the message protocol stack stage process. As shown in Figure 3, it is the flow chart of the protocol stack stage for the virtual network card to receive packets. First, the scheduler processes all protocol packets according to the registered network packet interruption behavior, and sends the packets to the IP layer for processing. The validity check is pending. After that, execute the AIRT_HOOK(ip_rcv_finish) hook function to judge the packet rate, set the flag bit, and judge whether it is a multicast packet according to the route. If it is multicast, call the multicast forwarding function. If it is a unicast packet, call unicast forwarding. The function collects IP fragments according to the IP packet serial number, calls the ip_local_deliver_finish hook function, rebuilds the buffer data structure, strips the IP header, sends it to the CPU for processing, restarts receiving packets, and exits after receiving all the packets.

When the virtual network card sends data packets to the application through AIRT-ROS, when the sending queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified to slow down the sending speed. As shown in Figure 1, the driver of the virtual network card is divided into a four-layer structure, namely the network protocol interface layer, the network device interface layer, the network driver interface layer, and the device media layer. Set a hook function in the NIC to pre-determine the status of the sending queue of the virtual network card. The setting and execution process of the hook function are the same as above, and will not be repeated here.

The flow chart of the virtual network card sending data packets is shown in Figure 4. First, create a packet sending interface, then determine the routing information, rebuild the buffer area for sending and receiving packets, that is, rebuild the buffer data structure, add a new IP header to the original packet header, and return according to the route. As a result, the IP header is set, the LOCALOUT hook function is called to judge the packet rate, the flag bit is set, the forwarding status of the current packet is set, the subsequent steps of sending packets are performed after the status is marked, and the packet and the maximum transmission unit (MTU) are judged. ) relationship, if the buffered data structure is greater than or equal to the MTU, the packet will be fragmented, and if it is less than the MTU, the packet does not need to be fragmented, and finally the sending request enters the buffer queue of the network card and waits for scheduling to be sent.

The virtual network card of the present invention is applied to AIRT-ROS, and the virtual network card sends data packets and receives data packets based on AIRT-ROS. The following 5 introduces AIRT-ROS in detail, as shown in Figure 5, for AIRT-ROS Architecture diagram, the AIRT-ROS is a multi-core dual operating system based on the AMP architecture, one operating system is Linux, the other operating system is the RTERS real-time operating system, the AIRT-ROS includes the Linux kernel and the RTERS kernel, the Linux The kernel includes a Robot Operating System (ROS, Robot Operating System), the first Hyper Text Transfer Protocol (HTTP, Hyper Text Transfer Protocol), the File Transfer Protocol (FTP, File Transfer Protocol), and the first Local Advanced Programmable Interrupt Controller (LAPIC, Local Advanced Programmable Interrupt Controller), the RTERS kernel includes a robot real-time operating system (RT-ROS, Real Time-Robot Operating System), a second hypertext transfer protocol (HTTP, Hyper Text Transfer Protocol) and a second local advanced programmable Interrupt controller (LAPIC, Local Advanced Programmable Interrupt Controller), the Linux kernel and the RTERS kernel are connected through an IPI interface, and the robot operating system and the robot real-time operating system are virtualized through a virtual switch (vSwitch, Virtual Switch). connection, the first local advanced programmable interrupt controller is connected to the non-real-time device and the virtual network card through the first input and output advanced programmable interrupt controller, and the second local advanced programmable interrupt controller is connected through the second input and output advanced programmable interrupt controller. The programming interrupt controller is connected to the real-time device, and the virtual network card sends data packets to the application program through AIRT-ROS, or the virtual network card receives data packets sent by the application program through AIRT-ROS.

Through the above technical solutions, a solution method for AIRT-ROS virtual network card packet loss provided by the present invention can solve the problem of virtual network card data packet loss, and the virtual network card of the present invention sends and receives data packets on the AIRT-ROS system. The system allows Linux and RTERS operating systems to execute non-real-time processes and real-time processes respectively; respond to non-real-time device interrupts and real-time device interrupts respectively; support communication between non-real-time processes and real-time processes; It reduces the workload of driving general-purpose external devices. AIRT-ROS will not affect the execution speed of RTERS for real-time processes when the Linux system is under heavy load. On the other hand, AIRT-ROS communicates with Linux in the RTERS kernel, so that the robot control algorithm packaged in ROS can be easily called in the real-time system, which greatly reduces the workload of developing robot control algorithms.

In a specific implementation of the embodiment of the present invention, when the virtual network card A sends a data packet to the target virtual network card X, the data packet starts from the virtual network card A, passes through the device B, the device C and the device D in sequence to the target virtual network card X. .

When the sending queue of virtual network card A exceeds the maximum transmission unit value, virtual network card A first sends a bandwidth query command to each forwarding node on the data packet transmission link, that is, virtual network card A sends a bandwidth query command to device B, and device B sends a bandwidth query command to device B. Returns the remaining bandwidth to virtual NIC A.

After receiving the remaining bandwidth of device B on the link, virtual network card A determines whether the remaining bandwidth of device B on the link is greater than the data volume of the data packet to be sent. Send to device B, if not, set the flag and notify the upper application to slow down the sending speed. After receiving the data packet, device B sends a bandwidth query command to device C, and device C returns its remaining bandwidth to device B. After receiving the remaining bandwidth of device C on the link, device B determines the remaining bandwidth of device C on the link. Whether the remaining bandwidth is greater than the data volume of the data packet to be sent, if so, device B uses the backup link to send the data packet to device C; if not, sets the flag and informs device B to slow down the sending speed; device C receives the data After receiving the packet, it sends a bandwidth inquiry command to device D, and device D returns its remaining bandwidth to device C. After receiving the remaining bandwidth of device D on the link, device C determines whether the remaining bandwidth of device D on the link is equal. It is larger than the data volume of the data packet to be sent. If yes, device C uses the backup link to send the data packet to device D. If not, it sets the flag and informs device C to slow down the sending speed; Network card X sends a bandwidth query command, and virtual network card X returns its remaining bandwidth to device D. After receiving the remaining bandwidth of virtual network card X on the link, device D determines whether the remaining bandwidth of virtual network card X on the link is greater than or equal to The data volume of the data packet to be sent. If yes, device D uses the backup link to send the data packet to virtual network card X. If not, it sets the flag and informs device D to slow down the sending speed.

Applying the above embodiments of the present invention, when the remaining bandwidth of each device on the data packet transmission link meets the requirements, the transmission speed of the data packet is not slowed down; only when the remaining bandwidth of each device does not meet the requirements. It will slow down the sending speed of data packets and ensure the real-time performance of data packets sent by the virtual network card.

Further, when the data volume of the data packets in the sending queue of the virtual network card A reaches a preset number of times of the maximum transmission unit, the virtual network card A first sends a bandwidth inquiry instruction to the forwarding node on the data packet transmission link, and The preset number is less than 1. If virtual network card A receives the remaining bandwidth of the device at the next level on the link, it determines whether the remaining bandwidth of the device on the link is greater than the data volume of the data packet to be sent. If virtual network card A uses the backup link The channel sends the data packet to its next-level device, if not, sets the flag bit and informs the upper-layer application to slow down the sending speed.

For example, the data packet sending speed of the upper-layer application is 15/second. When the data volume of the data packets in the sending queue reaches 0.8 times the maximum transmission unit, the data packet sending speed of the upper-layer application is reduced to 12/second, and then Sending data packets, because the upper-layer application needs a process to respond to the command, during this process, the sending queue will also receive the data packets at the original speed, and the remaining capacity of the maximum transmission unit is used to store the data packets generated in the process, and then can To avoid the problem of packet loss caused by the fact that the upper-layer application still sends data packets at the original speed when the maximum transmission queue is full, the maximum transmission queue cannot store the data packets.

It should be emphasized that the situation that the maximum transmission queue is full means that the sending queue of the virtual network card exceeds the maximum transmission unit value.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (3)

1. an AIRT-ROS virtual network card packet loss solution, characterized in that the method comprises: When the application sends data packets to the virtual network card through AIRT-ROS, when the receiving queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified to slow down the sending speed; the virtual network card sends data to the application through AIRT-ROS When the sending queue of the virtual network card exceeds the maximum transmission unit value, the flag is set and the upper-layer application is notified to slow down the sending speed. 2. a kind of AIRT-ROS virtual network card packet loss solution method according to claim 1 is characterized in that, described AIRT-ROS is a multi-core dual operating system based on AMP architecture, wherein one operating system is Linux, and the other is operating The system is RTERS real-time operating system, the AIRT-ROS includes a Linux kernel and an RTERS kernel, and the Linux kernel includes a robot operating system, a first hypertext transfer protocol, a file transfer protocol, and a first local advanced programmable interrupt controller, so The RTERS kernel includes a robot real-time operating system, a second hypertext transfer protocol and a second local advanced programmable interrupt controller, the Linux kernel is connected to the RTERS kernel through an IPI interface, and the robot operating system is connected to the robot in real time. The operating system performs virtual connection through the virtual switch, the first local advanced programmable interrupt controller is connected to the non-real-time device and the virtual network card through the first input and output advanced programmable interrupt controller, and the second local advanced programmable interrupt controller is connected. The real-time device is connected through the second input and output advanced programmable interrupt controller, the virtual network card sends data packets to the application program through AIRT-ROS, or the virtual network card receives data packets sent by the application program through AIRT-ROS. 3. a kind of AIRT-ROS virtual network card packet loss solution method according to claim 1, is characterized in that, the driver of described virtual network card is divided into four-layer structure, namely network protocol interface layer, network device interface layer, network The driver interface layer and the device media layer, by setting hook functions in the network protocol interface layer and the network driver interface layer, pre-determine the status of the receiving queue or the sending queue of the virtual network card, and notify the upper-layer application to control the transmission message rate.

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