Server/Client C program to work under Fedora Core Linux 6.

/******************************************libraries declarations******************/

#include <stdio.h>

#include <netdb.h> //for network

#include <sys/types.h> //for system calls,socket data types

#include <sys/socket.h> //structures for sockets

#include <stdlib.h>

#include <netinet/in.h> //structures for internet domain addresses

#include <string.h>

// Linux server port, Win server port and ip

#define PORT 1117

#define SERVER_PORT 5001

#define SERVER_IPv4 "172.24.1.37"

/*******************************************main***********************************/

int main(void)

{

struct sockaddr_in6 servaddr; //IPv6 structure for the server

struct sockaddr_in6 claddr; // IPv6 structure for the client

struct sockaddr_in clientaddr;//IPv4 structure for the client

//struct sockaddr_in serveraddr;//ipv4 structure for the server

int sock_ipv6_server, newsocketfd, cllen;

char mess[2048];

char comm[256], dest[2048], tmp[2048], v1[256], v2[1024];

char RecvComm[256];

int retval;

FILE *fp;

int i, j;

char buf[1024];

int sock_ipv4_client, servlen;

char mail[256];

// create connection to Win client

sock_ipv6_server = socket(AF_INET6, SOCK_STREAM, 0);

if (sock_ipv6_server == -1)

{

printf("Cannot create socket!!!");

exit(0);

}

printf("We managed to create the socket with the number: %d\n",sock_ipv6_server);

//bzero((char*)&servaddr,sizeof(servaddr));

memset((char *)&servaddr, 0, sizeof(servaddr));

memset((char *) &claddr,0,sizeof(claddr));

// vals for IPv6 address

servaddr.sin6_family = AF_INET6;

servaddr.sin6_port = htons(PORT);

servaddr.sin6_addr=in6addr_any;//accept any IP address defined on that machine

// actual connection step 1

retval = bind(sock_ipv6_server, (struct sockaddr *)&servaddr,sizeof(servaddr));

if (retval == -1)

{

printf ("ERROR on binding\n");

exit(0);

}

//step 2

retval = listen(sock_ipv6_server,1);

if(retval == -1)

{

printf("ERROR on listen()\n");

exit(0);

}

// step 3

cllen = sizeof(claddr);

newsocketfd = accept(sock_ipv6_server,(struct sockaddr *) &claddr,&cllen) ;

if (newsocketfd == -1) printf("ERROR on accept");

// read user list to file

system("who -q >users.txt");

//open file for read

fp=fopen("users.txt","r");

//count all

i=1;

do

{

//get one user

fscanf(fp,"%s ",v1);

i++;

}while(!feof(fp));

fclose(fp);

//read actual users

fp=fopen("users.txt","r");

for(j=1; j < i-2; j++)

{

fscanf(fp,"%s ",v1);

sprintf( v2, "%d.%s\r\n", j, v1);

strcat(tmp, v2);

}

// close file

fclose(fp);

//delete temp file

system("rm users.txt");

// test

printf(tmp);

//send message to win client

mess[0]='\0';

strcat(mess, "Bun venit!\r\n");

strcat(mess, tmp);

//debug

printf("================mess====================== ");

printf(mess);

//actual send

send(newsocketfd,mess,sizeof(mess),0) ;

// receive *COMMyy*email* from Win client

if (recv(newsocketfd,RecvComm,sizeof(RecvComm),0) == -1)

{

//means we have errors in receiving the command from the client

//we treat these errors

printf("Conection failed\n");

if (shutdown(newsocketfd,2)<0)

{

printf("We have error on closing the connection");

exit(EXIT_FAILURE);

}

printf("Connection shutdown\n");

if (close(newsocketfd)<0)

{

printf("Error on closing the socket\n");

exit(EXIT_FAILURE);

}

printf("Close connection\n");

exit(0);

}

// ok receive

printf("ok RecvComm\n");

//debug

printf("================received======================\n ");

printf(RecvComm);

printf("====================================== \n");

// Send command to Win server

//parse command

// write message to file recvComm.txt, to be able to exec cut

fp = fopen("recvComm.txt", "w");

fprintf( fp, "%s", RecvComm );

fclose(fp);

//get Comm value

system("cut -d* -f2 recvComm.txt > tmp.txt" );

fp = fopen("tmp.txt", "r");

fscanf( fp, "%s", comm);

fclose(fp);

system("cut -d* -f3 recvComm.txt > tmp.txt" );

fp = fopen("tmp.txt", "r");

fscanf( fp, "%s", mail);

fclose(fp);

//delete temp files

system("rm tmp.txt recvComm.txt");

sscanf( RecvComm, "*%s*%s", comm, mail);

printf("comm=%s email=%s\n",comm, mail);

if(strcmp(comm,"COMM01")==0)

{

// the right command

//connect to Win server

//0. create socket

sock_ipv4_client=socket(AF_INET,SOCK_STREAM,0);

if (sock_ipv4_client==-1)

{

printf("Cannot create socket!!!");

exit(0);

}

printf("We managed to create the socket with the number%d\n",sock_ipv4_client);

clientaddr.sin_family = AF_INET;

clientaddr.sin_port = htons(SERVER_PORT);

clientaddr.sin_addr.s_addr = inet_addr(SERVER_IPv4);

//step 1

retval=connect(sock_ipv4_client,(struct sockaddr*)&clientaddr,sizeof(clientaddr));

if (retval==-1)

{

printf("Error on connection to the server \n");

exit(0);

}

else

{

printf("All OK\n");

//send the command to the Win server

send(sock_ipv4_client,"netsh interface ip show address",30,0);

//receive result from Win server

retval=recv(sock_ipv4_client,buf,sizeof(buf),0);

if (retval==-1)

{

printf("ERoare mare: result from win server missing!!!!!\n");

exit(0);

}else

{

printf("BINe!\n");

//send result to Win client

send(newsocketfd,buf,sizeof(buf),0);

//write result to file

//open file for write

fp=fopen("result.txt","w");

fprintf(fp, "%s\n", buf);

//send mail

sprintf( tmp, "mail < result.txt %s", mail);

system( tmp );

}

}//else retval==-1

}// if COMM1

else

{

printf("Wrong command");

//send message to Win client

send(newsocketfd,"Command not implemented.", 24, 0);

}

//close all socket

close(newsocketfd);

close(sock_ipv6_server);

close(sock_ipv4_client);

}//main