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|
//A TCP server asking for every clients
//on it's network to send their
//logfiles
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <time.h>
#define MSGSIZE 256
#define UDPPORT 12346
#define TCPPORT 12347
main(int argc, char **argv){
int sockfd, ok, addr_in_size, optval = 1, timeout = 1*60, cc, pid;
u_short portnum = UDPPORT;
struct sockaddr_in *to, *from; //target/source
struct hostent *toinfo;
char ask[] = "ENQ\0", go[] = "ACK\0", msg[MSGSIZE];//Enquiring all the clients (ENQ)/clear to send (ACK)
char* htoname = "255.255.255.255";//broadcasting (initially)
u_long toaddr, fromaddr;
time_t end;
to = (struct sockaddr_in *)malloc(sizeof(struct sockaddr_in));
from = (struct sockaddr_in *)malloc(addr_in_size);
if((toinfo = gethostbyname(htoname)) == NULL){
fprintf(stderr,"Error %d in gethostbyname: %s\n",
errno,sys_errlist[errno]);
exit(errno);
};
toaddr = *(u_long *)toinfo->h_addr_list[0];
addr_in_size = sizeof(struct sockaddr_in);
memset((char *)to,(char)0,addr_in_size);
to->sin_family = AF_INET;
to->sin_addr.s_addr = INADDR_BROADCAST;
to->sin_port = htons(portnum);
if((sockfd = socket (PF_INET, SOCK_DGRAM, 0)) == -1){
fprintf(stderr,"Error %d in socket: %s\n",errno,sys_errlist[errno]);
exit(errno);
};
if(setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, (char*)&optval, sizeof(optval))!=0){
fprintf(stderr,"Error %d in setting socket option: %s\n",errno,sys_errlist[errno]);
exit(errno);
}
ok = 1;
printf("Broadcasting logfiles query\n");
if(sendto(sockfd,ask,strlen(ask),0,(struct sockaddr *)to,
addr_in_size) == -1){
fprintf(stderr,"Error %d in sendto: %s\n",errno,sys_errlist[errno]);
exit(errno);
}
printf("Waiting for answers for %d seconds...\n", timeout);
end = time(NULL)+timeout;
while(time(NULL) < end){
if((cc = recvfrom (sockfd,msg,MSGSIZE,0,(struct sockaddr *)from,
&addr_in_size)) == -1){
fprintf(stderr,"Error %d in recvfrom: %s\n",
errno,sys_errlist[errno]);
exit(errno);
}
fromaddr = from->sin_addr.s_addr;
msg[cc] = '\0';
if(strcmp(msg, go) == 0){
pid = fork();
switch(pid){
case 0:
//we are ready to get the file
printf("%s clear to send\n", gethostbyaddr((char *)&fromaddr,
sizeof(fromaddr),
AF_INET));
if(sendto(sockfd,ask,strlen(ask),0,(struct sockaddr *)to,
addr_in_size) == -1){
fprintf(stderr,"Error %d in sendto: %s\n",errno,sys_errlist[errno]);
exit(errno);
}
//Client ready for sending
getFileFromClient(gethostbyaddr((char *)&fromaddr, sizeof(fromaddr), AF_INET));
break;
case -1:
fprintf(stderr,"Error %d in fork: %s\n",errno,sys_errlist[errno]);
exit(errno);
break;
default:
break;
}
}else {
fprintf(stderr, "Error in client answer: %s answered %s, expecting %s\n", gethostbyaddr((char *)&fromaddr,
sizeof(fromaddr),
AF_INET), msg, go);
}
fprintf(stdout,"From %s port %d: %s\n",
(gethostbyaddr((char *)&fromaddr,
sizeof(fromaddr),
AF_INET))->h_name,
from->sin_port,msg);
}
}
int getFileFromClient(const char* from){
int listenfd,connfd,n;
struct sockaddr_in servaddr,cliaddr;
socklen_t clilen;
char mesg[MSGSIZE];
listenfd=socket(AF_INET,SOCK_STREAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
servaddr.sin_port=htons(32000);
bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));
listen(listenfd, TCPPORT);
//Got one client connected
clilen=sizeof(cliaddr);
connfd = accept(listenfd,(struct sockaddr *)&cliaddr,&clilen);
close (listenfd);
for(;;)
{
n = recvfrom(connfd,mesg,1000,0,(struct sockaddr *)&cliaddr,&clilen);
sendto(connfd,mesg,n,0,(struct sockaddr *)&cliaddr,sizeof(cliaddr));
printf("-------------------------------------------------------\n");
mesg[n] = 0;
printf("Received the following:\n");
printf("%s",mesg);
printf("-------------------------------------------------------\n");
}
close(connfd);
return 0;
} |
