#include <stdio.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <sys/types.h>#include <sys/socket.h>#include <pwd.h>#include "ipmsg.h"#include "udp_comm.h"#include "utils.h"int msg_sock_fd;int file_sock_fd;/*change here to send individually*/char broad_cast_addr[16]="255.255.255.255";void init_socket(){	struct sockaddr_in local_addr;	const int broadcast_on = 1;		msg_sock_fd = socket(AF_INET,SOCK_DGRAM,0);	local_addr.sin_family = AF_INET;	local_addr.sin_port = htons(IPMSG_DEFAULT_PORT);	local_addr.sin_addr.s_addr = htonl(INADDR_ANY);		if(setsockopt(msg_sock_fd,SOL_SOCKET,SO_BROADCAST,&broadcast_on,sizeof(broadcast_on)) < 0)	{		fprintf(stderr,"setsockopt() failed:%s\n",strerror(errno));		close(msg_sock_fd);		exit(1);	}		if(bind(msg_sock_fd,(struct sockaddr *)&local_addr,sizeof(local_addr)) < 0)	{		fprintf(stderr,"bind() failed:%s\n",strerror(errno));		close(msg_sock_fd);		exit(1);	}}int send_msg(int msg_sock_fd,struct msg_info *msg){	char msg_buf[LEN_DGRAM];	int ret;	socklen_t addr_len;		addr_len = sizeof(msg->peer);		if((msg_sock_fd < 0)||(msg == NULL)) {		printf("BAD arugment to call send_msg().\n");		return -1;	}	form_msg(msg_buf,LEN_DGRAM,msg);		ret = sendto(msg_sock_fd,msg_buf,sizeof(msg_buf),0,(struct sockaddr *)&msg->peer,addr_len);	if(ret < 0) {		perror("sendto()");	}	return ret;}	int recv_msg(int msg_sock_fd,struct msg_info *msg){	char msg_buf[LEN_DGRAM];	int ret;	socklen_t addr_len;	struct sockaddr_in peer_addr;		//bzero(msg_buf,sizeof(msg_buf));	addr_len = sizeof(peer_addr);	ret = recvfrom(msg_sock_fd,msg_buf,sizeof(msg_buf),0,(struct sockaddr *)&peer_addr,&addr_len);	//	printf("\nmsg from :%s\n",inet_ntoa(peer_addr.sin_addr));//	printf("received:%s\n",msg_buf);	if(ret < 0)		return -1;	parse_msg(msg_buf,sizeof(msg_buf),msg);	memcpy(&msg->peer,&peer_addr,sizeof(msg->peer));	return ret;}int login(){	struct msg_info msg;	init_msg(&msg,IPMSG_NOOPERATION);	msg.peer.sin_family = AF_INET;	msg.peer.sin_port = htons(IPMSG_DEFAULT_PORT);	if(inet_pton(AF_INET,broad_cast_addr,&msg.peer.sin_addr) < 0)		printf("login:%s\n",strerror(errno));			/*send IPMSG_NOOPERATION*/	send_command(msg_sock_fd,&msg,IPMSG_NOOPERATION);		/*send IPMSG_BR_ENTRY*/	strncpy(msg.extended,local_user->pw_name,LEN_MSG);	send_command(msg_sock_fd,&msg,IPMSG_BR_ENTRY|IPMSG_DIALUPOPT);	return 0;}int logout(){	struct msg_info msg;	init_msg(&msg, IPMSG_NOOPERATION);  	msg.peer.sin_family = AF_INET;	msg.peer.sin_port = htons(IPMSG_DEFAULT_PORT);  	if (inet_pton(AF_INET,broad_cast_addr , &msg.peer.sin_addr)<0)	printf("logout: error\n");	send_command(msg_sock_fd,&msg,IPMSG_NOOPERATION);	strncpy(msg.extended, local_user->pw_name, LEN_MSG);  	send_command(msg_sock_fd,&msg,IPMSG_BR_EXIT);	printf("Good Bye!\n");	return 0;}/*Use current msg_info struct to send COMMAND,unchange its original command flags*/void send_command(int msg_sock_fd,struct msg_info *msg,unsigned int commands){	unsigned int flags = msg->command;	msg->command &= IPMSG_NOOPERATION;	msg->command |= commands;	send_msg(msg_sock_fd,msg);	msg->command = flags;}