dpdk进行tcp会话重组代码-DPDK中文网

以下是一个简单的DPDK TCP会话重组代码示例：

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <rte_mbuf.h>
#include <rte_tcp.h>

#define MAX_SESSIONS 1024

struct tcp_session {
    uint32_t src_ip;
    uint16_t src_port;
    uint32_t dst_ip;
    uint16_t dst_port;
    uint32_t seq;
    uint32_t ack;
    uint16_t window;
    char *buf;
    uint32_t len;
    bool complete;
};

struct tcp_session sessions[MAX_SESSIONS];

int find_session_index(struct rte_tcp_hdr *tcp_hdr)
{
    int i;

    for (i = 0; i < MAX_SESSIONS; i++) {
        if (!sessions[i].complete &&
            sessions[i].src_ip == tcp_hdr->src_addr &&
            sessions[i].src_port == tcp_hdr->src_port &&
            sessions[i].dst_ip == tcp_hdr->dst_addr &&
            sessions[i].dst_port == tcp_hdr->dst_port &&
            sessions[i].seq + sessions[i].len == tcp_hdr->sent_seq) {
            return i;
        }
    }

    return -1;
}

void process_packet(struct rte_mbuf *pkt)
{
    struct rte_ipv4_hdr *ip_hdr = rte_pktmbuf_mtod_offset(pkt, struct rte_ipv4_hdr *, 0);
    struct rte_tcp_hdr *tcp_hdr = rte_pktmbuf_mtod_offset(pkt, struct rte_tcp_hdr *, sizeof(struct rte_ipv4_hdr));
    int session_idx;
    uint32_t payload_len;

    if (tcp_hdr->tcp_flags & RTE_TCP_ACK_FLAG) {
        session_idx = find_session_index(tcp_hdr);
        if (session_idx < 0) {
            // Start a new session
            session_idx = 0;
            while (sessions[session_idx].complete)
                session_idx++;
            sessions[session_idx].src_ip = tcp_hdr->src_addr;
            sessions[session_idx].src_port = tcp_hdr->src_port;
            sessions[session_idx].dst_ip = tcp_hdr->dst_addr;
            sessions[session_idx].dst_port = tcp_hdr->dst_port;
            sessions[session_idx].seq = tcp_hdr->sent_seq;
            sessions[session_idx].ack = tcp_hdr->recv_ack;
            sessions[session_idx].window = tcp_hdr->rx_win;
            sessions[session_idx].buf = malloc(sizeof(char) * rte_pktmbuf_pkt_len(pkt));
            memcpy(sessions[session_idx].buf, rte_pktmbuf_mtod(pkt, char *), rte_pktmbuf_pkt_len(pkt));
            sessions[session_idx].len = rte_pktmbuf_pkt_len(pkt);
        } else {
            // Continue existing session
            payload_len = rte_pktmbuf_pkt_len(pkt) - sizeof(struct rte_ipv4_hdr) - sizeof(struct rte_tcp_hdr);
            memcpy(sessions[session_idx].buf + sessions[session_idx].len,
                   rte_pktmbuf_mtod_offset(pkt, char *, sizeof(struct rte_ipv4_hdr) + sizeof(struct rte_tcp_hdr)),
                   payload_len);
            sessions[session_idx].len += payload_len;
            sessions[session_idx].ack = tcp_hdr->recv_ack;
            sessions[session_idx].window = tcp_hdr->rx_win;
        }

        if (tcp_hdr->tcp_flags & RTE_TCP_FIN_FLAG) {
            sessions[session_idx].complete = true;
            printf("Session %d completed\n", session_idx);
        }
    }
}

int main(int argc, char *argv[])
{
    struct rte_mbuf *pkt;

    // Initialize DPDK here

    while (true) {
        // Receive packets here
        // ...

        pkt = receive_packet();

        if (pkt != NULL) {
            process_packet(pkt);
            rte_pktmbuf_free(pkt);
        }
    }

    return 0;
}

这个例子使用一个简单的会话数组来存储TCP会话，每当收到一个ACK包时，它会检查是否已经有一个与该包匹配的会话存在。如果找不到，则创建一个新会话并将数据包缓冲区复制到会话缓冲区中。如果找到了一个现有的会话，则在现有缓冲区的末尾追加数据包缓冲区，并更新ACK和窗口大小字段。如果收到FIN标志，则会话被标记为完成。

请注意，此代码仅处理TCP会话重组，不涉及任何其他协议或功能。在实际应用中，可能需要添加错误处理、超时机制、流量控制等额外特性。