www.pudn.com > Linux_serial_network_src.rar > server.c
/* server.c ed server
* Copy Right 2003 Li Suke , Software School of Peking University.
* This program's task is to read data from /dev/ed_tx
* and write data into /dev/ed_rec. /dev/ed_tx is for the
* network driver to store the tx data; /dev/ed_rec is for
* the network driver to get the data.
* Attention: we use SLIP protocol's END ESC to pack the packet.
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "ed_ioctl.h"
#define BUFFER_SIZE 2048
/* These defination is from SLIP protocol. */
#define END 0300
#define ESC 0333
#define ESC_END 0334
#define ESC_ESC 0335
/* open the ttyS0 serial port */
int open_port(void)
{
int fd;
fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY );
if (fd == -1)
{
perror("open_port: Unable to open /dev/ttyS0 - ");
return -1;
}
else
fcntl(fd, F_SETFL, 0);
return (fd);
}
/* set up the options for serial port */
int setup_com(int fd){
struct termios options;
tcgetattr(fd, &options);
/*
* Set the baud rates to 19200...
*/
cfsetispeed(&options, B38400);
cfsetospeed(&options, B38400);
/*
* Enable the receiver and set local mode...
*/
options.c_cflag |= (CLOCAL | CREAD);
/*
* Set global options.
*/
options.c_cflag |= PARENB;
options.c_cflag &= ~PARODD;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
/* set the input options */
options.c_iflag &=~(IXON | IXOFF | IXANY);
options.c_iflag &=~(INLCR | IGNCR | ICRNL);
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
/* set the output options */
options.c_oflag &= ~OPOST;
/* set the timeout options */
options.c_cc[VMIN] = 0;
options.c_cc[VTIME] = 10;
tcsetattr(fd, TCSANOW, &options);
return 1;
}
int open_dev(char *file_name){
int fd;
fd = open(file_name ,O_RDWR);
if(fd < 0)
{
perror("Open ed_rec device error:");
return -1;
}
return fd;
}
void close_dev(int fd){
close(fd);
}
/*
* pack the frame and prepare for sending the packets.
*/
int frame_pack(unsigned char *src, unsigned char *des, int len)
{
unsigned char *ptr = des;
unsigned char c;
*ptr++ = END;
while (len-- > 0) {
switch(c = *src++) {
case END:
*ptr++ = ESC;
*ptr++ = ESC_END;
break;
case ESC:
*ptr++ = ESC;
*ptr++ = ESC_ESC;
break;
default:
*ptr++ = c;
break;
}
}
*ptr++ = END;
return (ptr - des );
}
/*
* unpack the frame.
*/
int frame_unpack(unsigned char *src, unsigned char *des)
{
unsigned char *ptr = des;
unsigned char c;
int count = 0;
int esc_flag = 0;
if(*src++ != END)
return 0;
while( ((c=*src++) != END) && (count < BUFFER_SIZE))
{
switch(c){
case ESC_END:
if(esc_flag == 1){
*ptr++ = END;
esc_flag = 0;
}
else
*ptr++ = c;
break;
case ESC_ESC:
if(esc_flag ==1){
*ptr++ = ESC;
esc_flag = 0;
}
break;
case END:
esc_flag = 0;
break;
case ESC:
esc_flag = 1;
break;
default:
*ptr++ = c;
esc_flag = 0;
break;
}
}
if(count >= BUFFER_SIZE){
printf("some error happen in frame unpack().\n");
return BUFFER_SIZE;
}
return (ptr - des);
}
int main(int argc ,char *argv[]){
int fd;
int fd_rec;
int fd_tx;
unsigned char buffer_rec[BUFFER_SIZE];
unsigned char buffer_tx[BUFFER_SIZE];
unsigned char buffer_tx_pack[BUFFER_SIZE];
unsigned char buffer[BUFFER_SIZE];
unsigned char *buffer_ptr;
unsigned char *rec_ptr;
unsigned char *tx_ptr;
int flag;
int nbytes;
pid_t pid;
int tx_length;
int rec_length;
int i;
rec_ptr = buffer_rec;
tx_ptr = buffer_tx;
buffer_ptr = buffer;
int rec_count;
int tx_count;
fd_rec = open_dev("/dev/ed_rec");
fd_tx = open_dev("/dev/ed_tx");
if(fd_rec <0 || fd_tx <0)
{
close(fd);
return 0;
}
fd = open_port();
if(fd < 0)
return 0;
setup_com(fd);
pid = fork();
if(pid < 0){
printf("Can not creat the process\n");
close(fd);
close(fd_rec);
close(fd_tx);
return 0;
}
if(pid ==0){
/* read process */
for (;;)
{
/* read data from /dev/ttyS0, and write the data into buffer_rec,wait for the
kernel to get the data.
*/
flag = 0;
rec_count = 0;
buffer_ptr = buffer;
while ((nbytes = read(fd, rec_ptr, BUFFER_SIZE-1)) > 0){
rec_length = 0;
for(i=0;i< nbytes;i++){
rec_count += 1;
rec_length = rec_length +1;
if((buffer_rec[i])== END){
flag = flag +1;
if(flag ==2)
break;
}
}
if(rec_count < BUFFER_SIZE){
memcpy(buffer_ptr,rec_ptr,rec_length);
buffer_ptr += rec_length;
rec_length = 0;
}
/* we recieve two ENDs */
if(flag == 2){
flag = 0;
buffer_ptr = buffer;
memset(buffer_rec,0,sizeof(buffer_rec));
rec_ptr = buffer_rec;
rec_count =frame_unpack(buffer_ptr,rec_ptr);
#ifdef _DEBUG
printf("\n Service recieve :\n");
for(i=0;i0){
int length;
/* write process */
for (;;)
{
/* read data from /dev/ttyS0, and write the data into buffer_rec,wait for the
kernel to get the data.
*/
tx_ptr = buffer_tx;
ioctl(fd_tx,IOCTL_SET_BUSY,1);
if((nbytes = read(fd_tx, tx_ptr, BUFFER_SIZE-1)) > 0)
{
tx_count = frame_pack(tx_ptr,buffer_tx_pack,nbytes);
#ifdef _DEBUG
printf("\nSend bytes:%d\n",nbytes);
printf("\nServer send\n");
for(i=0;i