Design And Implementation Of Data Capture System Software Based On PCI-E Interface

In recent years, with the rapid development of network technology, people's lives become increasingly close with the network. In order to protect network security, traffic on the network must be captured and analyzed. In general, the traffic is large, so there must be a mechanism to capture the traffic for the high-speed network. This thesis studies such a high-speed network data capture technology.In the field of network data capture, the traditional system is made up with NIC, network protocol stack and packet capture library. The traditional system use software to filter and capture data. Also, NIC is not optimized for data capture. So, in data capture, the performance of traditional system is poor. To meet the demand for high-speed network data capture, the system has made the following improvements, including: First, using a dedicated capture card, which is responsible for filtering the data, thus avoiding the performance loss caused by software; Second, the transmission unit is the data block, thereby effectively reducing the number of interrupts; Third, data transmission is not via the network protocol stack to avoid the performance loss; Fourth, use zero-copy mechanisms, dedicated card directly transmit data to the program's buffer zone, to avoid data replication. Based on these ideas, we constructed a high performance data capture system which is made up of a dedicated capture card and capture card softwares. According to the test, the system can meet the demand for high-speed network.This thesis mainly discusses the capture card software. This thesis analyzes the software design ideas, system design ideas, and key technologies of the system. Through testing, we conclude that the system can meet the actual demand.