Unix域套接字入门

来源：互联网发布：大数据平台搭建编辑：程序博客网时间：2024/05/14 08:28

#include <sys/un.h>#include <sys/socket.h>#include <stdio.h>#include <stdlib.h>#include <unistd.h>intmain(int argc, char **argv){        int sockfd；        socklen_t len;  // unistd.h          struct sockaddr_un addr1, addr2;        if (argc != 2){                printf("usage: unixbind <pathname>\n");                exit(1);        }        if((sockfd = socket(PF_UNIX, SOCK_STREAM, 0))<0){                printf("socket error!\n");                exit(1);        }        unlink(argv[1]);                //删除防止存在        bzero(&addr1, sizeof(addr1));        addr1.sun_family = PF_UNIX;        strncpy(addr1.sun_path, argv[1], sizeof(addr1.sun_path)-1);        bind(sockfd, (struct sockaddr *) &addr1, SUN_LEN(&addr1));         //len =  (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))                len = sizeof(addr2);        getsockname(sockfd, (struct sockaddr *) &addr2, &len);//获得刚绑定的路径名，值-结果参数；        printf("bound name = %s, returned len = %d\n", addr2.sun_path, len);        exit(0);}

通用套接字地址结构 (sys/socket.h)：

typedef unsigned short sa_family_t; //2 B
struct sockaddr {
sa_family_t sa_family; /* address family, AF_xxx */
char sa_data[14]; /* 14 bytes of protocol address */

IPv4 套接字地址结构（netinet/in.h）：

/* Structure describing an Internet socket address. */
struct sockaddr_in
{
    __SOCKADDR_COMMON (sin_);
    in_port_t sin_port;                     /* Port number. */
    struct in_addr sin_addr;            /* Internet address. */

    /* Pad to size of `struct sockaddr'. */
    unsigned char sin_zero[sizeof (struct sockaddr) - __SOCKADDR_COMMON_SIZE - sizeof (in_port_t) - sizeof (struct in_addr)]; //sin_zero[8]
                           /* 字符数组sin_zero[8]的存在是为了保证结构体struct sockaddr_in的大小和结构体struct sockaddr的大小相等 */
};
下面是struct sockaddr_in中用到两个数据类型，具体定义如下：
/* Type to represent a port. */
typedef uint16_t in_port_t;

struct in_addr其实就是32位IP地址
struct in_addr {
        unsigned long s_addr;
};

Unix domain socket地址结构：

struct sockaddr_un{

sa_family_t sun_family;

char sun_path[104]; //所以需要macro SUN_LEN来得到真正的长度。

};

getsocketname(int sockfd, struct sockaddr *localaddr, socklen_t *addrlen)

获得与某个套接字关联的本地协议地址结构。

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