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ServerMCP.c
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ServerMCP.c
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// Server
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<netdb.h>
#define PORT 4950
#define BUFSIZE 1024
void send_to_all(int j, int i, int sockfd, int nbytes_recvd, char *recv_buf, fd_set *master)
{
if(FD_ISSET(j,master)){A
if(j != sockfd && j != i){
if(send(j,recv_buf, nbytes_recvd,0)==-1){
perror("send");
}
}
}
}
void send_recv(int i, fd_set *master, int sockfd, int fdmax)
{
int nbytes_recvd, j;
char recv_buf[BUFSIZE], buf[BUFSIZE];
if((nbytes_recvd = recv(i, recv_buf, BUFSIZE, 0)) <= 0){
if(nbytes_recvd ==0){
printf("socket %d hung up\n", i);
}
else{
perror("recv");
}
close(i);
FD_CLR(i, master);
}
else{
recv_buf[nbytes_recvd]='\0';
printf("%s\n", recv_buf);
for(j=0;j<=fdmax;j++){
send_to_all(j,i,sockfd, nbytes_recvd, recv_buf, master);
}
}
}
void connection_accept(fd_set *master, int *fdmax, int sockfd, struct sockaddr_in *client_addr)
{
socklen_t addrlen;
int newsockfd;
addrlen = sizeof(struct sockaddr_in);
if((newsockfd = accept(sockfd, (struct sockaddr *)client_addr, &addrlen)) ==-1)
{
perror("accept");
exit(1);
}
else
{
FD_SET(newsockfd, master);
if(newsockfd > *fdmax)
{
*fdmax = newsockfd;
}
printf("new connection from %s on port %d \n",inet_ntoa(client_addr->sin_addr), ntohs(client_addr->sin_port));
}
}
void connect_request(int *sockfd, struct sockaddr_in *my_addr)
{
int yes = 1;
if((*sockfd = socket(AF_INET, SOCK_STREAM, 0))==-1){
perror("socket");
exit(1);
}
my_addr->sin_family = AF_INET;
my_addr->sin_port = htons(4950);
my_addr->sin_addr.s_addr = INADDR_ANY;
memset(my_addr->sin_zero, '\0',sizeof my_addr->sin_zero);
//code to reuse the port. wait for 1 minute and code is not required.
if(setsockopt(*sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1)
{
perror("setsockopt");
exit(1);
}
if(bind(*sockfd, (struct sockaddr *)my_addr, sizeof(struct sockaddr)) == -1)
{
perror("Unable to bind");
}
if(listen(*sockfd, 10) == -1)
{
perror("listen");
exit(1);
}
printf("\n TCPServer waiting for client on port 4950\n");
fflush(stdout);
}
int main()
{
fd_set master;
fd_set read_fds;
int fdmax, i;
int sockfd= 0;
struct sockaddr_in my_addr, client_addr;
FD_ZERO(&master);
FD_ZERO(&read_fds);
connect_request(&sockfd, &my_addr);
FD_SET(sockfd, &master);
fdmax=sockfd;
printf("Fdmax before while=%d\n", fdmax);
while(1){
read_fds=master;
if(select(fdmax+1, &read_fds, NULL, NULL, NULL)==-1){
perror("select");
exit(4);
}
for(i=0; i<=fdmax; i++){
//printf("Fdmax inside for =%d\n", fdmax);
if(FD_ISSET(i, &read_fds)){
if(i==sockfd){
connection_accept(&master, &fdmax, sockfd, &client_addr);}
else{
send_recv(i, &master, sockfd, fdmax);}
}
}
}
return 0;
}