server-api-bind

原型

用于绑定一个本地地址到套接字

函数原型

// sockfd:要绑定的套接字
// addr:要绑定的地址信息
// addrlen:地址信息长度
//
// return:
//      On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.
//      成功返回0,失败返回-1且会设置errno的值
//
// error:
//      EACCES
//          The address is protected, and the user is not the superuser.
//          权限不足
//      EADDRINUSE
//          The given address is already in use.
//      EBADF
//          sockfd is not a valid descriptor.
//          参数sockfd 非合法socket处理代码。
//      EINVAL
//          The socket is already bound to an address.
//      ENOTSOCK
//          sockfd is a descriptor for a file, not a socket.
//          参数sockfd为一文件描述词，非socket。
//
//      The following errors are specific to UNIX domain (AF_UNIX) sockets:
//      EACCES
//          Search permission is denied on a component of the path prefix.  (See also path_resolution(7).)
//      EADDRNOTAVAIL
//          A nonexistent interface was requested or the requested address was not local.
//      EFAULT
//          addr points outside the user's accessible address space.
//      EINVAL
//          The addrlen is wrong, or the socket was not in the AF_UNIX family.
//      ELOOP
//          Too many symbolic links were encountered in resolving addr.
//      ENAMETOOLONG
//          addr is too long.
//      ENOENT
//          The file does not exist.
//      ENOMEM
//          Insufficient kernel memory was available.
//      ENOTDIR
//          A component of the path prefix is not a directory.
//      EROFS
//          The socket inode would reside on a read-only file system.
int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);

使用参考

支持一个客户端的回射服务器

#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#include<stdlib.h>
#include<stdio.h>
#include<errno.h>
#include<string.h>

#define ERR_EXIT(m)\
    do\
    {\
        perror(m); \
        exit(EXIT_FAILURE); \
    }while (0)

int main(void)
{
    int listenfd;
    /*if ((listenfd = socket(PF_INET, SOCK_STREAM, 0))<0)*/
    if ((listenfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
        ERR_EXIT("socket");

    struct sockaddr_in servaddr;
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(5188);
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    /*servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");*/
    /*inet_aton("127.0.0.1", &servaddr.sin_addr);*/

    int on = 1;
    if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
        ERR_EXIT("SETSOCKOPT") ;

    if (bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)
        ERR_EXIT("BIND");

    if (listen(listenfd, SOMAXCONN) < 0)
        ERR_EXIT("LISTEN");

    struct sockaddr_in peeraddr;
    socklen_t peerlen = sizeof(peeraddr);
    int conn;
    if ((conn = accept(listenfd, (struct sockaddr*)&peeraddr, &peerlen)) < 0)
        ERR_EXIT("ACCEPT");

    printf("ip=%s port=%d\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port));

    char recvbuf[1024];
    while (1)
    {
        memset(recvbuf, 0, sizeof(recvbuf));
        int ret = read(conn, recvbuf, sizeof(recvbuf));
        fputs(recvbuf, stdout);
        write(conn, recvbuf, ret);
    }

    close(conn);
    close(listenfd) ;

    return 0;
}