Linux客户端网口输入转串口输出

概要与环境

使用socket通信方式，建立连接，在服务端将获取到的数据调用串口发送即可

服务端为Linux，客户端为Linux或Windows

测试过程中请：使用iptables -F，免得让人感觉不好。

另外，在Linux下的C语言头文件一部分不可以在Windows系统上运行，可能导致一些不便。

socket通信

参阅：https://www.cnblogs.com/wuyepeng/p/9717236.html

要真正实现合适的通信，仍然需要加之修改。在本例测试过程中，发送端的输出数据在接收端会多出两个字节长度。相信是在发送端造成的。

C客户端的测试代码基本相同：

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
 
#define MYPORT  8887
#define BUFFER_SIZE 1024
 
int main()
{
    ///定义sockfd
    int sock_cli = socket(AF_INET,SOCK_STREAM, 0);
 
    ///定义sockaddr_in
    struct sockaddr_in servaddr;
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(MYPORT);  ///服务器端口
    servaddr.sin_addr.s_addr = inet_addr("xxxxxx");  ///服务器ip
 
    ///连接服务器，成功返回0，错误返回-1
    if (connect(sock_cli, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0)
    {
        perror("connect");
        exit(1);
    }
 
    char sendbuf[BUFFER_SIZE];
    char recvbuf[BUFFER_SIZE];
    while (fgets(sendbuf, sizeof(sendbuf), stdin) != NULL)
    {
//    int len = strlen(sendbuf);
//    if(sendbuf[len-1] == '
'){sendbuf[len--]=0;}
    printf("send:%s",sendbuf);
        send(sock_cli, sendbuf, strlen(sendbuf),0); ///发送
        recv(sock_cli, recvbuf, strlen(recvbuf),0); ///接收
        fputs(recvbuf, stdout);
        memset(sendbuf, 0, sizeof(sendbuf));
        memset(recvbuf, 0, sizeof(recvbuf));
    }
    close(sock_cli);
    return 0;
}

C服务端的测试代码：该代码存在致命的缺陷未修正。运行以后，在客户一端敲入几次回车即可显示。

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <asm/termios.h>
#define DEV_NAME  "/dev/pts/1"
#define MYPORT  8887
#define QUEUE   20
#define BUFFER_SIZE 1024

int mainFunction()
{
    int fd;//serial port
    ///定义sockfd
    int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);

    ///定义sockaddr_in
    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(MYPORT);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
    if(fd < 0) 
    {
            perror(DEV_NAME);
            return -1;
    }
    printf("%d port is ready
");
    ///bind，成功返回0，出错返回-1
    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1)
    {;
    }

    ///listen，成功返回0，出错返回-1
    if(listen(server_sockfd,QUEUE) == -1)
    {
        perror("listen error
");
        return;
    }

    ///客户端套接字
    char buffer[BUFFER_SIZE];
    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);

    ///成功返回非负描述字，出错返回-1
    int conn = accept(server_sockfd, (struct sockaddr*)&client_addr, &length);
    if(conn<0)
    {
        perror("connect error
");
        return;
    }

    while(1)
    {
        memset(buffer,0,sizeof(buffer));
        int len = recv(conn, buffer, sizeof(buffer),0);
        if(len<=0)
        {
            printf("maybe disconnected... restart:
");
            break;
        }
        fputs(buffer, stdout);
        send(conn, strcat("send message success:",buffer), len, 0);
    }
    close(conn);
    close(server_sockfd);

}
void main()
{
    while(1)
    {
        mainFunction();
    }
}

python实现通信参阅：https://blog.csdn.net/su_bao/article/details/80380465

python实现的通信更加方便。阅读链接信息即可。该python的客户端程序，修改参数可以直接与C语言的socket服务端通信。通信过程中，接收端和发送的字节数相同。

该代码在python2中可能输入数据需要添加双引号，

串口控制

串口部分可以参阅：周立功【开发指南】M6G2C&A6G2C;系列核心板软件开发指南。

该指南中，在第16章，有详细的串口发送案例。其中也详细的书写了一些自定义参数的函数，可供使用。

以下是基本相同的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <asm/termios.h>
#define DEV_NAME  "/dev/pts/1"
int main (int argc, char *argv[])
{
    int fd;
    int len, i,ret;
    char buf[] = "hello ZLG!";

    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
    if(fd < 0) {
            perror(DEV_NAME);
            return -1;
    }
    printf("%d",fd);
    len = write(fd, buf, sizeof(buf));
    if (len < 0) {
        printf("write data error 
");
    }
    printf("%s", buf);
    return(0);
}

另外需要测试的是串口控制，则需要使用虚拟串口。

这里可以采用他人python写的一个虚拟串口脚本，建立两个互通的串口？：https://blog.csdn.net/qq_42973043/article/details/82888075

这里可以做出一些删减后的代码，基本相同如下：

import pty
import os
import select

def mkpty():
    #
    master1, slave = pty.openpty()
    slaveName1 = os.ttyname(slave)
    master2, slave = pty.openpty()
    slaveName2 = os.ttyname(slave)
    print '/nslave device names: ', slaveName1, slaveName2
    return master1, master2

if __name__ == "__main__":

    master1, master2 = mkpty()
    while True:        
        rl, wl, el = select.select([master1,master2], [], [], 1)
        for master in rl:
            data = os.read(master, 128)
            if master==master1:
                print "master1 receive data: %d data:" % len(data)
                print data
            else:
                print "master2 receive data: %d data:" % len(data)
                print data

测试方式相同。

综合

修正部分如下，该部分去掉了一些错误。

    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1)
    {
        
    ;
    }

C语言服务端完整代码如下

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <asm/termios.h>
#define DEV_NAME  "/dev/pts/1"
#define MYPORT  8887
#define QUEUE   20
#define BUFFER_SIZE 1024

int mainFunction()
{
    int fd;//serial port
    ///定义sockfd
    int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);

    ///定义sockaddr_in
    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(MYPORT);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
	if(fd < 0) 
	{
			perror(DEV_NAME);
			return -1;
	}
    printf("port is ready
");
    cfsetispeed(fd,115200);
    cfsetospeed(fd,115200);
    //bind，成功返回0，出错返回-1
    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1)
    {
        
	;
    }
    ///listen，成功返回0，出错返回-1
    if(listen(server_sockfd,QUEUE) == -1)
    {
        perror("listen error
");
	return;
    }
    ///客户端套接字
    char buffer[BUFFER_SIZE];
    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);

    ///成功返回非负描述字，出错返回-1
    int conn = accept(server_sockfd, (struct sockaddr*)&client_addr, &length);
    if(conn<0)
    {
        perror("connect error
");
	return;
    }

    while(1)
    {
        memset(buffer,0,sizeof(buffer));
        int len = recv(conn, buffer, sizeof(buffer),0);
	if(len<=0)
        {
            printf("maybe disconnected... restart:
");
            break;
        }
//	if(buffer[0]=='
')
//	{
//	    printf("end by user");
//	    break;
//	}
	len = write(fd, buffer,len);
	if (len < 0) {
		printf("write data error 
");
		break;
	}
        send(conn,buffer, len, 0);
    }
    close(conn);
    close(server_sockfd);

}
void main()
{
    while(1)
    {
        mainFunction();
    }
}

当然啦，一个用户还可以，要是多个用户，那就用多线程喽

代码折起不会长

 编译命令：gcc -lpthread server.c -o server

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <asm/termios.h>
#include <pthread.h>
#define DEV_NAME  "/dev/pts/1"
#define MYPORT  8887
#define QUEUE   20
#define BUFFER_SIZE 1024

int fd;//serial port
void * recvMsg(void *con)
{
    char buffer[BUFFER_SIZE];
    int conn=(int)*(int *)con;
    int len;
    while(1)
    {
        memset(buffer,0,sizeof(buffer));
        len=recv(conn, buffer, sizeof(buffer),0);

        if( len<=0 ){printf("maybe disconnected... 
");break;}
        if( write(fd, buffer,len)< 0 ) {printf("write data error 
");break;}

        send(conn,buffer, len, 0);
    }
    close(conn);
    pthread_exit(NULL);
}

int mainFunction()
{

    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
    if(fd < 0) 
    {
            printf("DEV_NAME ERROR!");
            return -1;
    }
    printf("port is ready
");
    cfsetispeed(fd,115200);
    cfsetospeed(fd,115200);

    int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);

    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(MYPORT);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1);
    if(listen(server_sockfd,QUEUE) == -1){return;}

    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);

    while(1)
    {
        int conn = accept(server_sockfd, (struct sockaddr*)&client_addr, &length);if(conn<0){continue;}
        pthread_t recv_thread;
        pthread_create(&recv_thread, NULL, recvMsg,(void *)&conn);
    }
    close(server_sockfd);

}
void main()
{
    while(1)
    {
        mainFunction();
    }
}

　　

单用户的异步双向转发

服务端的C

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <asm/termios.h>
#include <pthread.h>
#define DEV_NAME  "/dev/ttyS2"
#define MYPORT  8887
#define QUEUE   20
#define BUFFER_SIZE 1024

int fd;//serial port


void * recvCom(void *con)
{
    int len;
    char buffer[BUFFER_SIZE];
    int conn=(int)*(int *)con;
    while(1)
    {
        len=read(fd, buffer, sizeof(buffer));
        if(len>0)
        {
            printf("receive:%s",buffer);
            send(conn,"you receive:", 12, MSG_DONTWAIT);
            send(conn,buffer, len, MSG_DONTWAIT);
        }
    }

}

void * recvSocket(void *con)
{
    char buffer[BUFFER_SIZE];
    int conn=(int)*(int *)con;
    int len;
    printf("connected
");
    pthread_t recv_comm;
    pthread_create(&recv_comm, NULL, recvCom,(void *)&conn);
    while(1)
    {
        memset(buffer,0,sizeof(buffer));
        len=recv(conn, buffer, sizeof(buffer),0);
 
        if( len<=0 ){printf("maybe disconnected... 
");pthread_cancel(recv_comm);break;}
        if( write(fd, buffer,len)< 0 ) {printf("write data error 
");break;}
        send(conn,"you send:", 9, 0);
        send(conn,buffer, len, 0);
    }
    close(conn);
    //pthread_exit(NULL);
}


void * socketAndSerial(void *con)
{
    int conn=(int)*(int *)con;
    recvSocket((void *)&conn);
}
int mainFunction()
{
 
    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
    if(fd < 0) 
    {
            printf("DEV_NAME ERROR!");
            return -1;
    }
    printf("port is ready
");
    cfsetispeed(fd,115200);
    cfsetospeed(fd,115200);
 
    int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);
    
    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(MYPORT);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 
    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1);
    if(listen(server_sockfd,QUEUE) == -1){return;}
 
    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);
 
    int conn=-1;
    while((conn = accept(server_sockfd, (struct sockaddr*)&client_addr, &length))<0);
    close(server_sockfd);
    socketAndSerial((void *)&conn);
}
void main()
{
    while(1)
    {
        mainFunction();
    }
}

客户端的Python

from socket import *
import threading
import ctypes
import inspect
HOST = '192.168.0.78' # or 'localhost'
PORT = 8887
BUFSIZ =1024
ADDR = (HOST,PORT)

tcpCliSock = socket(AF_INET,SOCK_STREAM)
tcpCliSock.connect(ADDR)

def _async_raise(tid, exctype):
    tid = ctypes.c_long(tid)
    if not inspect.isclass(exctype):
        exctype = type(exctype)
    res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, ctypes.py_object(exctype))
    if res == 0:
        raise ValueError("invalid thread id")
    elif res != 1:
        ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, None)
        raise SystemError("PyThreadState_SetAsyncExc failed")

def readBuffer():
    while True:
        data1 = tcpCliSock.recv(BUFSIZ)
        print(data1.decode('utf-8'))


a=threading.Thread(target=readBuffer,args=())
a.start()
                 
while True:
     data1 = input('>')
     #data = str(data)
     if not data1:
        _async_raise(a.ident, SystemExit)
        break
     tcpCliSock.send((data1).encode())

tcpCliSock.close()


 

　　

更正可使用的16进制转发，用户完全传输

服务端

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <asm/termios.h>
#include <pthread.h>
#define DEV_NAME  "/dev/ttyS2"
#define MYPORT  8887
#define QUEUE   20
#define BUFFER_SIZE 1024

int fd;//serial port


void * recvCom(void *con)
{
    int len;
    char buffer[BUFFER_SIZE];
    int conn=(int)*(int *)con;
    int i;
    while(1)
    {
        len=read(fd, buffer, sizeof(buffer));
        if(len>0)
        {
            char *p=buffer;
            printf("serial msg:");
            for(i=0;i<len;i++)
                    printf("%2x ",buffer[i]);
            printf("
");
            send(conn,"you receive:", 12, MSG_DONTWAIT);
            send(conn,buffer, len, MSG_DONTWAIT);
        }
    }

}

void * recvSocket(void *con)
{
    char buffer[BUFFER_SIZE];
    int conn=(int)*(int *)con;
    int len;
    int i;
    printf("connected
");
    pthread_t recv_comm;
    pthread_create(&recv_comm, NULL, recvCom,(void *)&conn);
    while(1)
    {
        memset(buffer,0,sizeof(buffer));
        len=recv(conn, buffer, sizeof(buffer),0);
        printf("socket msg:");
        for(i=0;i<len;i++)
                printf("%2x ",buffer[i]);
        printf("
");
        if( len<=0 ){printf("maybe disconnected... 
");pthread_cancel(recv_comm);break;}
        if( write(fd, buffer,len)< 0 ) {printf("write data error 
");break;}
        send(conn,"you send:", 9, 0);
        send(conn,buffer, len, 0);
    }
    close(conn);
    //pthread_exit(NULL);
}


void * socketAndSerial(void *con)
{
    int conn=(int)*(int *)con;
    recvSocket((void *)&conn);
}
int mainFunction()
{
 
    fd = open(DEV_NAME, O_RDWR | O_NOCTTY);
    if(fd < 0) 
    {
            printf("DEV_NAME ERROR!");
            return -1;
    }
    printf("port is ready
");
    cfsetispeed(fd,115200);
    cfsetospeed(fd,115200);
 
    int server_sockfd = socket(AF_INET,SOCK_STREAM, 0);
    
    struct sockaddr_in server_sockaddr;
    server_sockaddr.sin_family = AF_INET;
    server_sockaddr.sin_port = htons(MYPORT);
    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 
    while(bind(server_sockfd,(struct sockaddr *)&server_sockaddr,sizeof(server_sockaddr))==-1);
    if(listen(server_sockfd,QUEUE) == -1){return;}
 
    struct sockaddr_in client_addr;
    socklen_t length = sizeof(client_addr);
 
    int conn=-1;
    while((conn = accept(server_sockfd, (struct sockaddr*)&client_addr, &length))<0);
    close(server_sockfd);
 
    socketAndSerial((void *)&conn);
    
}
void main()
{
    while(1)
    {
        mainFunction();
    }
}

用户端

from socket import *
import threading
import ctypes
import inspect
HOST = '192.168.0.78' # or 'localhost'
PORT = 8887
BUFSIZ =1024
ADDR = (HOST,PORT)

tcpCliSock = socket(AF_INET,SOCK_STREAM)
tcpCliSock.connect(ADDR)

def _async_raise(tid, exctype):
    tid = ctypes.c_long(tid)
    if not inspect.isclass(exctype):
        exctype = type(exctype)
    res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, ctypes.py_object(exctype))
    if res == 0:
        raise ValueError("invalid thread id")
    elif res != 1:
        ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, None)
        raise SystemError("PyThreadState_SetAsyncExc failed")

def readBuffer():
    while True:
        data1 = tcpCliSock.recv(BUFSIZ)
        print(data1)


a=threading.Thread(target=readBuffer,args=())
a.start()
                 
while True:
     data1 = input('>')
     #data = str(data)
     if not data1:
        break
     tcpCliSock.send((data1).encode())
     
_async_raise(a.ident, SystemExit)
tcpCliSock.close()