Dr Rahul Deole -IT Expert -Tata Consulting Engineers Limited
LINUX SOCKE TPROGRAMMING SOURCE CODE USING
Source Code Linux- TCP/IP Client & TCP/IP Server Program
/* tcpServer.c */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h> /* close */
#define SUCCESS 0
#define ERROR 1
#define END_LINE 0x0A
#define SERVER_PORT 1500
#define MAX_MSG 100
/* function readline */
int read_line();
int main (int argc, char *argv[]) {
int sd, newSd, cliLen;
struct sockaddr_in cliAddr, servAddr ;
char line[MAX_MSG];
/* create socket */
sd = socket(AF_INET, SOCK_STREAM, 0);
if(sd<0) { perror("cannot open socket ");
return ERROR; }
/* bind server port */
servAddr.sin_family = AF_INET;
servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
servAddr.sin_port = htons(SERVER_PORT);
if(bind(sd, (struct sockaddr *) &servAddr, sizeof(servAddr))<0) {
perror("cannot bind port ");
return ERROR;
}
listen(sd,5);
while(1) {
printf("%s: waiting for data on port TCP %u\n",argv[0],SERVER_PORT);
cliLen = sizeof(cliAddr);
newSd = accept(sd, (struct sockaddr *) &cliAddr, &cliLen);
if(newSd<0) {
perror("cannot accept connection ");
return ERROR;
}
/* init line */
memset(line,0x0,MAX_MSG);
/* receive segments */
while(read_line(newSd,line)!=ERROR) {
printf("%s: received from %s:TCP%d : %s\n", argv[0],
inet_ntoa(cliAddr.sin_addr),
ntohs(cliAddr.sin_port), line);
/* init line */
memset(line,0x0,MAX_MSG);
} /* while(read_line) */
} /* while (1) */
}
//* You can set END_CHAR to whatever means endofline for you. (0x0A is \n)*/
/* read_lin returns the number of bytes returned in line_to_return */
int read_line(int newSd, char *line_to_return) {
static int rcv_ptr=0;
static char rcv_msg[MAX_MSG];
static int n;
int offset;
offset=0;
while(1) {
if(rcv_ptr==0) {
/* read data from socket */
memset(rcv_msg,0x0,MAX_MSG); /* init buffer */
n = recv(newSd, rcv_msg, MAX_MSG, 0); /* wait for data */
if (n<0) {
perror(" cannot receive data ");
return ERROR;
} else if (n==0) {
printf(" connection closed by client\n");
close(newSd);
return ERROR;
}
}
/* if new data read on socket */
/* OR */
/* if another line is still in buffer */
/* copy line into 'line_to_return' */
while(*(rcv_msg+rcv_ptr)!=END_LINE && rcv_ptr<n) {
memcpy(line_to_return+offset,rcv_msg+rcv_ptr,1);
offset++;
rcv_ptr++;
}
/* end of line + end of buffer => return line */
if(rcv_ptr==n-1) {
/* set last byte to END_LINE */
*(line_to_return+offset)=END_LINE;
rcv_ptr=0;
return ++offset;
}
/* end of line but still some data in buffer => return line */
if(rcv_ptr <n-1) {
/* set last byte to END_LINE */
*(line_to_return+offset)=END_LINE;
rcv_ptr++;
return ++offset;
}
/* end of buffer but line is not ended => */
/* wait for more data to arrive on socket */
if(rcv_ptr == n) {
rcv_ptr = 0;
}
} /* while */
}
=============================
/* tcpClient.c */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h> /* close */
#define SERVER_PORT 1500
#define MAX_MSG 100
int main (int argc, char *argv[]) {
int sd, rc, i;
struct sockaddr_in localAddr, servAddr;
struct hostent *h;
if(argc < 3) {
printf("usage: %s <server> <data1> <data2> ... <dataN>\n",argv[0]);
exit(1);
}
h = gethostbyname(argv[1]);
if(h==NULL) {
printf("%s: unknown host '%s'\n",argv[0],argv[1]);
exit(1);
}
servAddr.sin_family = h->h_addrtype;
memcpy((char *) &servAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
servAddr.sin_port = htons(SERVER_PORT);
/* create socket */
sd = socket(AF_INET, SOCK_STREAM, 0);
d<0) {
perror("cannot open socket ");
exit(1);
}
/* bindport number */
localAddr.sin_family = AF_INET;
localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
localAddr.sin_port = htons(0);
rc = bind(sd, (struct sockaddr *) &localAddr, sizeof(localAddr));
if(rc<0) {
printf("%s: cannot bind port TCP %u\n",argv[0],SERVER_PORT);
perror("error ");
exit(1);
}
/* connect to server */
rc = connect(sd, (struct sockaddr *) &servAddr, sizeof(servAddr));
if(rc<0) {
perror("cannot connect ");
exit(1);
}
for(i=2;i<argc;i++) {
rc = send(sd, argv[i], strlen(argv[i]) + 1, 0);
if(rc<0) {
perror("cannot send data ");
close(sd);
exit(1); }
printf("%s: data%u sent (%s)\n",argv[0],i-1,argv[i]);
}return 0; }
