Linux本地socket通信--AF_UNIX

        我们熟知的sockek通信一般都是基于IP的，最近见到了本机客户端与服务端通信的方法（虽然lo地址也可以本机通信），写了一些程序做实验，主要实现客户端和服务端套接字的连接、各自创建收发线程进行通信。由于功能没有优化，纠结了很久才贴上来，重点是AF_UNIX的功能已经实现了。其实AF_UNIX和AF_INET交互的流程是一样的，只不过创建套接字的宏不一样，以及数据结构的填充不一样。这种机制对Linux C编程模块化非常有用，尤其是两个进程间通信。
1、AF_UNIX对应的结构体。

struct socketaddr_un

{

 _SOCKADDR_COMMON(sun_);  // __SOCKADDR_COMMON(sun_) 宏定义对应的定义为 sa_family_t sun_family

 char sun_path[108];

};

        struct sockaddr_un是UNIX环境下套接字的地址形式，一般情况下，需要把sockaddr_un结构强制转换成sockaddr结构再传入系统调用函数中。

 

2、客户端代码。

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>

#define SERVER_SOCK_PATH "server_socket"

void *send_data(void *param);
void *recv_data(void *param);
int main(int argc, char *argv[])
{
struct sockaddr_un address;
int sockfd;
int len;
int i, bytes;
int result;
pthread_t send_id, recv_id;

sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (-1 == sockfd)
{
perror("socket");
exit(-1);
}

address.sun_family = AF_UNIX;
strcpy(address.sun_path, SERVER_SOCK_PATH);
len = sizeof(address);

result = connect(sockfd, (struct sockaddr *)&address, len);
if (-1 == result)
{
perror("connect");
close(sockfd);
exit(-1);
}

pthread_create(&send_id, NULL, send_data, &sockfd);
pthread_create(&recv_id, NULL, recv_data, &sockfd);

pthread_join(send_id,NULL);
pthread_join(recv_id,NULL);

close(sockfd);
return 0;
}
void *send_data(void *param)
{
int sock = 0;
int ret = 0;
int send_len = 0;
fd_set sendfd;
struct timeval timeout={1,0};
char string_send[128] = {0};

sock = *(int *)param;

while(1)
{
printf("Please enter string to send:\r\n");
memset(string_send, 0, sizeof(string_send));
scanf("%s", string_send);

FD_ZERO(&sendfd);
FD_SET(sock, &sendfd);
ret = select(sock + 1, NULL, &sendfd, NULL, &timeout);
if (ret <= 0)
{
continue;
}

if (FD_ISSET(sock, &sendfd))
{
send_len = send(sock, string_send, strlen(string_send), 0);
if (strlen(string_send) != send_len)
{
printf("send string fail!\r\n");
continue;
}
}
}

return;
}

void *recv_data(void *param)
{
int sock = 0;
int ret = 0;
int recv_len = 0;
fd_set recvfd;
struct timeval timeout={1,0};
char string_recv[128] = {0};

sock = *(int *)param;

while(1)
{
FD_ZERO(&recvfd);
FD_SET(sock, &recvfd);
ret = select(sock + 1, &recvfd, NULL, NULL, &timeout);
if (ret <= 0)
{
continue;
}

if (FD_ISSET(sock, &recvfd))
{
recv_len = recv(sock, string_recv, sizeof(string_recv), 0);
if (recv_len <= 0)
{
printf("recv string fail!\r\n");
continue;
}

printf("recv string:%s\r\n", string_recv);
}
}

return;
}

 

3、服务端代码。

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

#define SERVER_SOCK_PATH "server_socket"
void *send_data(void *param);
void *recv_data(void *param);
int main(int argc, char *argv[])
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_un server_address;
struct sockaddr_un client_address;
int i, bytes;
char ch_send, ch_recv;
pthread_t send_id, recv_id;

unlink(SERVER_SOCK_PATH);

server_sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (-1 == server_sockfd)
{
perror("socket");
exit(-1);
}

server_address.sun_family = AF_UNIX;
strcpy(server_address.sun_path, SERVER_SOCK_PATH);
server_len = sizeof(server_address);

bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
listen(server_sockfd, 5);

client_len = sizeof(client_address);

client_sockfd = accept(server_sockfd, (struct sockaddr *)&server_address, (socklen_t *)&client_len);

if (client_sockfd == -1)
{
perror("accept");
close (server_sockfd);
exit(-1);
}

pthread_create(&send_id, NULL, send_data, &client_sockfd);
pthread_create(&recv_id, NULL, recv_data, &client_sockfd);

pthread_join(send_id,NULL);
pthread_join(recv_id,NULL);

close(client_sockfd);
return 0;
}

void *send_data(void *param)
{
int sock = 0;
int ret = 0;
int send_len = 0;
fd_set sendfd;
struct timeval timeout={1,0};
char string_send[128] = {0};

sock = *(int *)param;

while(1)
{
printf("Please enter string to send:\r\n");
memset(string_send, 0, sizeof(string_send));
scanf("%s", string_send);

FD_ZERO(&sendfd);
FD_SET(sock, &sendfd);
ret = select(sock + 1, NULL, &sendfd, NULL, &timeout);
if (ret <= 0)
{
continue;
}

if (FD_ISSET(sock, &sendfd))
{
send_len = send(sock, string_send, strlen(string_send), 0);
if (strlen(string_send) != send_len)
{
printf("send string fail!\r\n");
continue;
}
}
}

return;
}

void *recv_data(void *param)
{
int sock = 0;
int ret = 0;
int recv_len = 0;
fd_set recvfd;
struct timeval timeout={1,0};
char string_recv[128] = {0};

sock = *(int *)param;

while(1)
{
FD_ZERO(&recvfd);
FD_SET(sock, &recvfd);
ret = select(sock + 1, &recvfd, NULL, NULL, &timeout);
if (ret <= 0)
{
continue;
}

if (FD_ISSET(sock, &recvfd))
{
recv_len = recv(sock, string_recv, sizeof(string_recv), 0);
if (recv_len <= 0)
{
printf("recv string fail!\r\n");
continue;
}

printf("recv string:%s\r\n", string_recv);
}

}

return;
}

 

4、测试结果。

略（功能可以保证已经实现，公司网络不能上传图片，&…#*%&*…（@￥…&）。