reuse_port.c

#include <stdio.h>
#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char **argv) {
    int listenfd, connfd;
    socklen_t clilen;
    struct sockaddr_in cliaddr, servaddr;

    listenfd = socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(9000);

    // sockfd为需要端口复用的套接字
    int opt = 1;
    setsockopt(listenfd, SOL_SOCKET, SO_REUSEPORT, (const void *)&opt, sizeof(opt));

    /* bind到本地地址，端口为9000 */
    int err = bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
    printf("%d\n", err);

    /* listen的backlog为1024 */
    listen(listenfd, 1024);

    /* 循环处理用户请求 */
    for (;;) {
        clilen = sizeof(cliaddr);
        connfd = accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
        printf("done\n");
        close(connfd);          /* 关闭连接套接字，注意不是监听套接字*/
    }
}