tcp支持ipv6例程

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本篇为记录linux socket支持ipv6的学习笔记，ipv6的tcp socket编程与ipv4并无过多差别，主要有两点：
1、在协议结构体上面有些差别；
2、tcp的客户端必须用setsockopt进行绑定网卡才能成功发送消息。
详细的请看代码。

tcp服务端程序：

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <arpa/inet.h>
#define MAXBUF 1024  
int main(int argc, char **argv)
{
    int sockfd, new_fd;
    socklen_t len;

    struct sockaddr_in6 my_addr, their_addr;

    unsigned int myport, lisnum;
    char buf[MAXBUF + 1];

    myport = 8888;
    lisnum = 2;

    if ((sockfd = socket(AF_INET6, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    } else
        printf("socket created\n");

    bzero(&my_addr, sizeof(my_addr));
    my_addr.sin6_family = AF_INET6;
    my_addr.sin6_port = htons(myport);
    if (argv[1])
        inet_pton(AF_INET6, argv[1], &my_addr.sin6_addr);
    else
        my_addr.sin6_addr = in6addr_any;

    if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr_in6))== -1) {
        perror("bind");
        exit(1);
    } else
        printf("binded\n");

    if (listen(sockfd, lisnum) == -1) {
        perror("listen");
        exit(1);
    } else
        printf("begin listen\n");
    while (1) {
        len = sizeof(struct sockaddr_in6);
        if ((new_fd = accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1) {
            perror("accept");
            exit(errno);
        } else
        {
            char buf_r[1024] ="";
            inet_ntop(AF_INET6, &their_addr.sin6_addr, buf_r, sizeof(buf_r));
            printf("server: connection from [%s], port %d, socket %d\n",  buf_r, their_addr.sin6_port, new_fd);
        }
        bzero(buf, MAXBUF + 1);
        strcpy(buf, "hello!!");
        /* 发消息给客户端 */
        len = send(new_fd, buf, strlen(buf), 0);
        if (len < 0)
            printf("send failed [%s], [%d]  [%s]\n",buf, errno, strerror(errno));
        else
            printf("send success [%s] [%d]\n", buf, len);

        bzero(buf, MAXBUF + 1);
        /* 接收客户端的消息 */
        len = recv(new_fd, buf, MAXBUF, 0);
        if (len > 0)
            printf("recv success  [%s] [%d]\n",   buf, len);
        else
            printf("recv fail! [%d]，[%s]\n", errno, strerror(errno));
    }

    close(sockfd);
    return 0;
}

tcp客户端程序：

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
#define MAXBUF 1024  
int main(int argc, char **argv)
{
    int sockfd, len;
    struct sockaddr_in6 dest;
    char buffer[MAXBUF + 1];
    char buf[1024] = "";
    if ((sockfd = socket(AF_INET6, SOCK_STREAM, 0)) < 0) {
        perror("Socket failed");
        exit(errno);
    }
    printf("socket created\n");
    //绑定网卡eth0
    setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", sizeof("eth0"));
    bzero(&dest, sizeof(dest));
    dest.sin6_family = AF_INET6;
    dest.sin6_port = htons(8888);
    if ( inet_pton(AF_INET6, argv[1], &dest.sin6_addr) < 0 ) {
        perror(argv[1]);
        exit(errno);
    }
    inet_ntop(AF_INET6, &dest.sin6_addr, buf, sizeof(buf));
    printf("%s\n", buf);

    printf("address created\n");

    /* 连接服务器 */
    if (connect(sockfd, (struct sockaddr *)&dest, sizeof(dest)) != 0) {
        printf("fail.[%s], [%d] sockfd is %d\n",strerror(errno), errno, sockfd);
        exit(errno);
    }
    printf("server connected\n");

    bzero(buffer, MAXBUF + 1);
    /* 接收服务器来的消息 */
    len = recv(sockfd, buffer, MAXBUF, 0);
    if (len > 0)
        printf("recv success  [%s] [%d]\n",  buffer, len);
    else
        printf("recv fail! [%d]，[%s]\n", errno, strerror(errno));

    bzero(buffer, MAXBUF + 1);
    strcpy(buffer, "how old are you");
    /* 发消息给服务器 */
    len = send(sockfd, buffer, strlen(buffer), 0);
    if (len < 0)
        printf
            ("send [%s] fail  [%d] [%s]\n",  buffer, errno, strerror(errno));
    else
        printf("send success [%s]  [%d]\n",  buffer, len);

    close(sockfd);
    return 0;
}