vs_send.c

/*----------------------------------------------------------------------------
  File:   vs_send.c
  Description: Simple RUDP sender that can be used to transfer files.
               Arguments: destination address * (dot quadded or host.domain),  
               remote port number, and a list of files
  Author: Chaitanya Dandugula
 
  This is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This softare is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  *--------------------------------------------------------------------------*/

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "rudp_api.h"
#include "event.h"
#include "vsftp.h"

#define MAXPEERS 32			/* Max number of remote peers */
#define MAXPEERNAMELEN 256		/* Max length of peer name */
/* 
 * Prototypes 
 */

int usage();
int filesender(int fd, void *arg);
void send_file(char *filename);
int eventhandler(rudp_socket_t rsocket, rudp_event_t event, struct sockaddr_in *remote);

/* 
 * Global variables
 */

int debug = 0;			/* Debug flag */
struct sockaddr_in peers[MAXPEERS];	/* IP address and port */
int npeers = 0;			/* Number of elements in peers */

/* 
 * usage: how to use program
 */

int usage() {
	fprintf(stderr, "Usage: vs_send [-d] host1:port1 [host2:port2] ... file1 [file2]... \n");
	exit(1);
}

int main(int argc, char* argv[]) {
	int port;
	char *hoststr;
	struct hostent* hp;
	struct in_addr *addr;
	int c;
	int i;

	/* 
	 * Parse and collect arguments
	 */
	opterr = 0;

	while ((c = getopt(argc, argv, "d")) != -1) {
		if (c == 'd') {
			debug = 1;
		}
		else 
			usage();
	}

	for (i = optind; i < argc; i++) {
		/* found last host:port? */
		if (strchr(argv[i], ':') == NULL)
			break;
		/* Make a copy of argument string that we can modify  */
		hoststr = (char *) malloc(strlen(argv[i]) + 1);
		if (hoststr == NULL) {
			fprintf(stderr, "vs_send: malloc failed\n");
			exit(1);
		}
		strcpy(hoststr, argv[i]);
		port = atoi(strchr(hoststr, ':') + 1);
		if (port <= 0) {
			fprintf(stderr, "Bad destination port: %d\n", 
				atoi(strchr(hoststr, ':') + 1));
			exit(1);
		}
		*strchr(hoststr, ':') = '\0';
		if ((hp = gethostbyname(hoststr)) == NULL || 
		    (addr = (struct in_addr *)hp->h_addr) == NULL) {
			fprintf(stderr,"Can't locate host \"%s\"\n", hoststr); 
			return(0);
		}
		memset((char *)&peers[npeers], 0, sizeof(struct sockaddr_in));
		peers[npeers].sin_family = AF_INET;
		peers[npeers].sin_port = htons(port);
		memcpy(&peers[npeers].sin_addr, addr, sizeof(struct in_addr));
		npeers++;
		free(hoststr);
	}
	/* Need at least one peer */
	if (npeers == 0)
		usage();

	if (optind >= argc) {
		usage();
	}

	/* Launch senders for each file */
	while (i < argc) { 
		send_file(argv[i++]);
	}

	eventloop(0);
	return 0;
}

/* 
 * eventhandler: callback function for RUDP events
 */

int eventhandler(rudp_socket_t rsocket, rudp_event_t event, struct sockaddr_in *remote) {
	
	switch (event) {
	case RUDP_EVENT_TIMEOUT:
		if (remote) {
			fprintf(stderr, "rudp_sender: time out in communication with %s:%d\n",
				inet_ntoa(remote->sin_addr),
				ntohs(remote->sin_port));
		}
		else {
			fprintf(stderr, "rudp_sender: time out\n");
		}
		exit(1);
		break;
	case RUDP_EVENT_CLOSED:
		if (debug) {
			fprintf(stderr, "rudp_sender: socket closed\n");
		}
		break;
	}
	return 0;
}

/*
 * send_file: initiate sending of a file. 
 * Create a RUDP socket for sending. Send the file name to the VS receiver.
 * Register a handler for input event, which will take care of sending
 * file data
 */

void send_file(char *filename) {
	struct vsftp vs;
	int vslen;
	char *filename1;
	int namelen;
	int file = 0;
	int p;
	rudp_socket_t rsock;

	if ((file = open(filename, O_RDONLY)) < 0) {
		perror("vs_sender: open");
		exit(-1);
	}
	rsock = rudp_socket(0);
	if (rsock == NULL) {
		fprintf(stderr, "vs_send: rudp_socket() failed\n");
		exit(1);
	}
	rudp_event_handler(rsock, eventhandler);

	vs.vs_type = htonl(VS_TYPE_BEGIN);

	/* strip of any leading path name */
	filename1 = filename;
	if (strrchr(filename1, '/'))
		filename1 = strrchr(filename1, '/') + 1;
	
	/* Copy file name into VS data */
	namelen = strlen(filename1) < VS_FILENAMELENGTH  ? strlen(filename1) : VS_FILENAMELENGTH;
	strncpy(vs.vs_info.vs_filename, filename1, namelen);

	vslen = sizeof(vs.vs_type) + namelen;
	for (p = 0; p < npeers; p++) {
		if (debug) {
			fprintf(stderr, "vs_send: send BEGIN \"%s\" (%d bytes) to %s:%d\n",
				filename, vslen, 
				inet_ntoa(peers[p].sin_addr), ntohs(peers[p].sin_port));
		}
		if (rudp_sendto(rsock, (char *) &vs, vslen, &peers[p]) < 0) {
			fprintf(stderr,"rudp_sender: send failure\n");
			rudp_close(rsock);		
			return;
		}
	}
	event_fd(file, filesender, rsock, "filesender");
}

/*
 * filesender: callback function for handling sending of the file.
 * Will be called when data is available on the file (which is always
 * true, until the file is closed...). 
 * Send file data. Detect end of file and tell VS peers that transfer is
 * complete
 */

int filesender(int file, void *arg) {
    rudp_socket_t rsock = 	(rudp_socket_t) arg;
    int bytes;
    struct vsftp vs;
    int vslen;
    int p;

    bytes = read(file, &vs.vs_info.vs_data,VS_MAXDATA);
    if (bytes < 0) {
	perror("filesender: read");
	event_fd_delete(filesender, rsock);
	rudp_close(rsock);		
    }
    else if (bytes == 0) {
	vs.vs_type = htonl(VS_TYPE_END);
	vslen = sizeof(vs.vs_type);
	for (p = 0; p < npeers; p++) {
	    if (debug) {
		fprintf(stderr, "vs_send: send END (%d bytes) to %s:%d\n", 
			vslen, inet_ntoa(peers[p].sin_addr), htons(peers[p].sin_port));
	    }
	    if (rudp_sendto(rsock, (char *) &vs, vslen, &peers[p]) < 0) {
		fprintf(stderr,"rudp_sender: send failure\n");
		break;
	    }
	}
	event_fd_delete(filesender, rsock);
	rudp_close(rsock);		
    }
    else {
	vs.vs_type = htonl(VS_TYPE_DATA);
	vslen = sizeof(vs.vs_type) + bytes;
	for (p = 0; p < npeers; p++) {
	    if (debug) {
		fprintf(stderr, "vs_send: send DATA (%d bytes) to %s:%d\n", 
			vslen, inet_ntoa(peers[p].sin_addr), htons(peers[p].sin_port));				
	    }
	    if (rudp_sendto(rsock, (char *) &vs, vslen, &peers[p]) < 0) {
		fprintf(stderr,"rudp_sender: send failure\n");
		event_fd_delete(filesender, rsock);
		rudp_close(rsock);		
		break;
	    }
	}
    }
    return 0;
}