C ipv6 兼容 ipv4 的 socket 多线程 源代码

IPv6兼容IPv4的socket多线程通常涉及到网络编程中的双栈技术，即在一个程序中同时支持IPv4和IPv6。在C语言中，你可以通过设置socket选项`IPPROTO_IPV6`来启用IPv6套接字功能，并在需要的时候选择发送或接收IPv4或IPv6的数据。

下面是一个简单的多线程示例，展示了如何创建一个服务器，每个线程处理来自不同协议族的连接：

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>
#include <pthread.h>

#define PORT 8080

void* thread_func(void* arg) {
    int sock = *(int*)arg;
    struct sockaddr_storage addr;
    socklen_t addr_len = sizeof(addr);

    // 确保可以接收IPv4和IPv6
    int one = 1;
    setsockopt(sock, IPPROTO_IP, IP_TOS, &one, sizeof(one));
    setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));

    while (1) {
        // 接收连接请求
        if (accept(sock, (struct sockaddr*)&addr, &addr_len) < 0) {
            perror("accept failed");
            break;
        }

        // 根据地址类型决定协议
        if (AF_INET == addr.ss_family) {
            // IPv4处理
            char ip[INET_ADDRSTRLEN];
            inet_ntop(AF_INET, &((struct sockaddr_in*)&addr)->sin_addr, ip, sizeof(ip));
            printf("Received connection from IPv4: %s\n", ip);
            // 处理连接...
        } else if (AF_INET6 == addr.ss_family) {
            // IPv6处理
            char ip[INET6_ADDRSTRLEN];
            inet_ntop(AF_INET6, &((struct sockaddr_in6*)&addr)->sin6_addr, ip, sizeof(ip));
            printf("Received connection from IPv6: %s\n", ip);
            // 处理连接...
        }
    }
}

int main() {
    int server_fd, new_sock;
    struct sockaddr_in6 serv_addr6, cli_addr6;
    struct sockaddr_in serv_addr4;

    server_fd = socket(AF_UNSPEC, SOCK_STREAM, 0);
    if (-1 == server_fd) {
        perror("socket failed");
        return 1;
    }

    // 设置IPv4和IPv6双栈
    bind(server_fd, (struct sockaddr*)&serv_addr6, sizeof(serv_addr6));
    serv_addr6.sin6_family = AF_INET6;
    serv_addr6.sin6_port = htons(PORT);
    sin6_addr_zero(&serv_addr6.sin6_addr);
    if (bind(server_fd, (struct sockaddr*)&serv_addr4, sizeof(serv_addr4)) < 0) {
        perror("binding to IPv4 failed");
    }

    listen(server_fd, 5);
    pthread_t threads[MAX_THREADS];

    // 创建线程
    for (int i = 0; i < MAX_THREADS; i++) {
        new_sock = accept(server_fd, NULL, NULL);
        if (new_sock < 0) {
            perror("accepting failed");
            continue;
        }

        pthread_create(&threads[i], NULL, thread_func, (void*)&new_sock);
    }

    // 等待所有线程结束
    for (int i = 0; i < MAX_THREADS; i++) {
        pthread_join(threads[i], NULL);
    }

    close(server_fd);
    return 0;
}