Implementing TCP data transmission based on DPDK

Implementing TCP data transmission based on DPDK

Based on DPDK (Data Plane Development Kit), use C language to develop efficient TCP data transmission functions, implement the basic TCP three-way handshake, and develop the server side.

Preparation for development

1. Installation of DPDK and related dependencies:
   a. To install DPDK, refer to the official DPDK documentation for installation: https://core.dpdk.org /doc/guides/linux_gsg/index.html
   b. Install the necessary C language development tool chain and libraries.
2. DPDK initialization and port configuration:
   a. Initialize the network card and use the dpdk-devbind command to bind the network card that needs to be bound to dpdk;
   b. Configure huge page memory;

Possible problems and solutions

1. Incompatible network card driver: Make sure the network card driver used is compatible with DPDK. Refer to the supported network card list in the DPDK documentation.
2. Insufficient memory: DPDK requires a lot of memory to improve performance. During initialization, try to allocate more memory to DPDK, or optimize the memory pool configuration.
3. Poor performance: Optimize CPU affinity settings to ensure DPDK threads run on dedicated CPU cores. Also, adjust mbuf and memory pool sizes to suit different workloads.
4. Packet loss and transmission delay: Optimize the congestion control algorithm and adjust it according to actual network conditions. At the same time, a more efficient data packet reassembly and retransmission mechanism is achieved.
5. System stability: Fully test the code to ensure that the system can work normally under various abnormal conditions.

Develop code

#include <stdio.h>
#include <stdbool.h>
#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_mbuf.h>
#include <rte_cycles.h>

// 定义 DPDK 配置参数
#define RX_RING_SIZE 128
#define TX_RING_SIZE 512
#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
#define BURST_SIZE 32

// TCP 头部结构
struct tcp_header {
    
    
    uint16_t src_port;
    uint16_t dest_port;
    uint32_t seq_num;
    uint32_t ack_num;
    uint8_t data_offset;
    uint8_t flags;
    uint16_t window_size;
    uint16_t checksum;
    uint16_t urgent_ptr;
} __attribute__((packed));

// TCP 状态枚举
enum tcp_state {
    
    
    CLOSED,
    SYN_SENT,
    SYN_RECEIVED,
    ESTABLISHED
};

// TCP 连接结构
struct tcp_connection {
    
    
    struct tcp_header header;
    enum tcp_state state;
};

// 定义 TCP 标志
#define SYN 0x02
#define ACK 0x10

// DPDK 网卡端口默认配置
static const struct rte_eth_conf port_conf_default = {
    
    
    .rxmode = {
    
     .max_rx_pkt_len = ETHER_MAX_LEN }
};

// 初始化网卡端口
static inline int
port_init(uint16_t port, struct rte_mempool *mbuf_pool)
{
    
    
    struct rte_eth_conf port_conf = port_conf_default;
    const uint16_t rx_rings = 1, tx_rings = 1;
    uint16_t nb_rxd = RX_RING_SIZE;
    uint16_t nb_txd = TX_RING_SIZE;
    int ret;

    // 检查端口是否有效
    if (port >= rte_eth_dev_count_avail()) {
    
    
        return -1;
    }

    // 配置网卡端口
    ret = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
    if (ret != 0) {
    
    
        return ret;
    }

    // 调整接收和发送描述符数量
    ret = rte_eth_dev_adjust_nb_rx_tx_desc(port, &nb_rxd, &nb_txd);
    if (ret != 0) {
    
    
        return ret;
    }

    // 设置接收队列
    ret = rte_eth_rx_queue_setup(port, 0, nb_rxd,
        rte_eth_dev_socket_id(port), NULL, mbuf_pool);
    if (ret < 0) {
    
    
        return ret;
    }

    // 设置发送队列
    ret = rte_eth_tx_queue_setup(port, 0, nb_txd,
        rte_eth_dev_socket_id(port), NULL);
    if (ret < 0) {
    
    
        return ret;
    }

    // 启动网卡端口
    ret = rte_eth_dev_start(port);
    if (ret < 0) {
    
    
        return ret;
    }

    // 开启端口混杂模式 //需要开启，否则可能收不到数据包
    rte_eth_promiscuous_enable(port);

    return 0;
}

// 主函数
int main(int argc, char *argv[])
{
    
    
	// 初始化 DPDK 环境
    int ret = rte_eal_init(argc, argv);
    if (ret < 0) {
    
    
        rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
    }

    struct rte_mempool *mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL",
        NUM_MBUFS, MBUF_CACHE_SIZE, 0, RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());
    if (mbuf_pool == NULL) {
    
    
        rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
    }

    uint16_t port_id = 0;
    if (port_init(port_id, mbuf_pool) != 0) {
    
    
        rte_exit(EXIT    FAILURE, "Cannot init port %" PRIu16 "\n", port_id);
	}
	
	printf("TCP handshake simulation with DPDK\n");
	
	struct tcp_connection conn;
	conn.state = CLOSED;
	conn.header.src_port = 12345;
	conn.header.dest_port = 80;
	
	// Send SYN
	conn.header.flags = SYN;
	conn.header.seq_num = 1000;
	printf("Sending SYN packet\n");
	
	// Receive SYN-ACK (simulate)
	conn.header.flags = SYN | ACK;
	conn.header.ack_num = conn.header.seq_num + 1;
	printf("Receiving SYN-ACK packet\n");
	
	// Send ACK
	conn.header.flags = ACK;
	conn.header.seq_num++;
	printf("Sending ACK packet\n");
	
	conn.state = ESTABLISHED;
	printf("Connection established\n");
	
	// Cleanup
	rte_eth_dev_stop(port_id);
	rte_eth_dev_close(port_id);
	
	printf("Finished\n");
	return 0;
}

DPDK framework diagram

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Please refer to dpdk information (including the original mind of the above framework diagram):DPDK reference material