ftp.c

proxy源代码,linux下的ftp 代理的源代码,大家多多支持啊

	return (line);
}

int cfputs(ftp_t *x, char *line)
{
	char	buffer[310];

	if (debug)
		fprintf (stderr, ">>> CLI: %s\n", line);

	snprintf (buffer, sizeof(buffer) - 2, "%s\r\n", line);
	write(1, buffer, strlen(buffer));

	return (0);
}


char *sfgets(ftp_t *x, char *line, int size)
{
	char *p;

	*line = 0;
	if ((p = readline_fd(x, x->fd.server, line, size)) == NULL)
		return (NULL);
	else if (debug != 0)
		fprintf (stderr, "SVR >>>: %s\n", p);

	return (line);
}

int sfputs(ftp_t *x, char *format, ...)
{
	int	len;
	char	buffer[310];
	va_list	ap;

	va_start(ap, format);
	vsnprintf (buffer, sizeof(buffer) - 10, format, ap);
	va_end(ap);

	if (debug)
		fprintf (stderr, ">>> SVR: %s\n", buffer);

	/*
	 * There are firewalls that don't like command to be split in
	 * two packets.  Notice: the `- 10' above is really important
	 * to protect the proxy against buffer overflows.
	 */

	strcat(buffer, "\r\n");
	len = strlen(buffer);

	/*
	 * SIGPIPE is catched but then ignored, we have to handle it
	 * one our own now -- 24APR02asg
	 */

	if (write(x->fd.server, buffer, len) != len) {
		syslog(LOG_NOTICE, "-ERR: error writing control connect, error= %s", strerror(errno));
		exit (1);
		}

/*
 *	write(x->fd.server, buffer, strlen(buffer));
 *	write(x->fd.server, "\r\n", 2);
 */
	return (0);
}

int sfputc(ftp_t *x, char *command, char *parameter, char *line, int size, char **here)
{
	int	rc;
	char	*p, buffer[300];

	if (command != NULL  &&  *command != 0) {
		if (parameter != NULL  &&  *parameter != 0)
			snprintf (buffer, sizeof(buffer) - 2, "%s %s", command, skip_ws(parameter));
		else
			copy_string(buffer, command, sizeof(buffer));

		sfputs(x, "%s", buffer);
		}
	
	if (sfgets(x, line, size) == NULL) {
		if (debug != 0)
			fprintf (stderr, "server disappered in sfputc(), pos #1\n");

		return (-1);
		}
	else if (strlen(line) < 3) {
		if (debug != 0)
			fprintf (stderr, "short server reply in sfputc()\n");

		return (-1);
		}

	rc = atoi(line);
	if (line[3] != ' '  &&  line[3] != 0) {
        	while (1) {
                	if (sfgets(x, line, size) == NULL) {
				syslog(LOG_NOTICE, "-ERR: lost server while reading client greeting: %s", x->server.name);
				exit (1);
				}

			if (strlen(line) < 3)
				/* line too short to be response's last line */ ;
			else if (line[3] != ' '  &&  line[3] != 0)
				/* neither white space nor EOL at position #4 */ ;
			else if (line[0] >= '0'  &&  line[0] <= '9'  &&  atoi(line) == rc)
                       		break;		/* status code followed by EOL or blank detected */
			}
        	}

	if (here != NULL) {
		p = skip_ws(&line[3]);
		*here = p;
		}

	return (rc);
}



int doquit(ftp_t *x)
{
	int	rc;
	char	resp[200];

	if ((rc = sfputc(x, "QUIT", "", resp, sizeof(resp), NULL)) != 221)
		syslog(LOG_NOTICE, "unexpected resonse to QUIT: %s", resp);

	cfputs(x, "221 goodbye");
	syslog(LOG_NOTICE, "%d QUIT", rc);
	
	return (0);
}


char *_getipnum(char *line, char **here, char *ip, int size)
{
	int	c, i, k;

	copy_string(ip, line, size);
	k = 0;
	for (i=0; (c = ip[i]) != 0; i++) {
		if (c == ',') {
			if (k < 3) {
				ip[i] = '.';
				k++;
				}
			else {
				ip[i++] = 0;
				break;
				}
			}
		}

	if (here != NULL)
		*here = &line[i];

	return (ip);
}

unsigned long _getport(char *line, char **here)
{
	unsigned long port;
	char	*p;

	p = line;
	port = strtoul(p, &p, 10);
	if (*p != ',')
		return (0);

	p++;
	port = (port << 8) + strtoul(p, &p, 10);
	if (here != NULL)
		*here = p;

	return (port);
}

int doport(ftp_t *x, char *command, char *par)
{
	int	c, rc;
	char	*p, line[200];
	dtc_t	*ch;

	ch = &x->ch;
	_getipnum(par, &p, ch->client.ipnum, sizeof(ch->client.ipnum));
	ch->client.port = _getport(p, &p);
	if (debug)
		fprintf (stderr, "client listens on %s:%u\n", ch->client.ipnum, ch->client.port);

	get_interface_info(x->fd.server, ch->outside.ipnum, sizeof(ch->outside.ipnum));
	ch->osock = bind_to_port(ch->outside.ipnum, 0);
	ch->outside.port = get_interface_info(ch->osock, line, sizeof(line));
	if (debug)
		fprintf (stderr, "listening on %s:%u\n", ch->outside.ipnum, ch->outside.port);

	copy_string(line, ch->outside.ipnum, sizeof(line));
	for (p=line; (c = *p) != 0; p++) {
		if (c == '.')
			*p = ',';
		}

	*p++ = ',';
	snprintf (p, 20, "%u,%u", ch->outside.port >> 8, ch->outside.port & 0xFF);


	/* Open port first */		
	ch->isock     = -1;
	ch->mode      = MODE_PORT;
	ch->state     = PORT_LISTEN;

	/* then send PORT cmd */
	rc = sfputc(x, "PORT", line, line, sizeof(line), &p);

	/* check return code */
	if (rc != 200){
		cfputs(x, "500 not accepted");
		close_ch(x, &x->ch);
		}
	else 
		cfputs(x, "200 ok, port allocated");



/*	if (rc != 200)
		cfputs(x, "500 not accepted");
	else {
		cfputs(x, "200 ok, port allocated");

		ch->isock  = -1;
		ch->mode   = MODE_PORT;
		ch->state  = PORT_LISTEN;
		}
*/

	*ch->command = 0;
	return (rc);
}

int dopasv(ftp_t *x, char *command, char *par)
{
	int	c, k, rc;
	char	*p, line[200];
	dtc_t	*ch;

	ch = &x->ch;
	rc = sfputc(x, "PASV", "", line, sizeof(line), &p);
	if (rc != 227) {
		cfputs(x, "500 not accepted");
		return (0);
		}


	/*
	 * Ende der Port-Koordinaten im Server-Response suchen.
	 */

	k = strlen(line);
	while (k > 0  &&  isdigit(line[k-1]) == 0)
		k--;

	if (isdigit(line[k-1])) {
		line[k--] = 0;
		while (k > 0  &&  (isdigit(line[k-1])  ||  line[k-1] == ','))
			k--;
		}

	/*
	 * line[k] sollte jetzt auf die erste Ziffer des PASV Response
	 * zeigen.
	 */

	if (isdigit(line[k]) == 0) {
		syslog(LOG_NOTICE, "can't locate passive response: %s", line);
		cfputs(x, "500 not accepted");
		return (0);
		}

	/*
	 * Auslesen der PASV IP-Nummer und des Ports.
	 */

	p = &line[k];
	_getipnum(p, &p, ch->server.ipnum, sizeof(ch->server.ipnum));
	ch->server.port = _getport(p, &p);
	if (debug)
		fprintf (stderr, "server listens on %s:%u\n", ch->server.ipnum, ch->server.port);

	get_interface_info(0, ch->inside.ipnum, sizeof(ch->inside.ipnum));
	ch->isock = bind_to_port(ch->inside.ipnum, 0);
	ch->inside.port = get_interface_info(ch->isock, line, sizeof(line));
	if (debug)
		fprintf (stderr, "listening on %s:%u\n", ch->inside.ipnum, ch->inside.port);

	snprintf (line, sizeof(line) - 2, "227 Entering Passive Mode (%s,%u,%u)",
			ch->inside.ipnum,
			ch->inside.port >> 8, ch->inside.port & 0xFF);
	for (p=line; (c = *p) != 0; p++) {
		if (c == '.')
			*p = ',';
		}

	cfputs(x, line);
	ch->osock = -1;
	ch->mode  = MODE_PASSIVE;
	ch->state = PORT_LISTEN;

	*ch->command = 0;
	ch->operation = 0;

	return (rc);
}


int dofeat(ftp_t *x)
{
	/*
	 * Not so easy because we have to align with the server response. 
	 */

	int	rc;
	char	*p, word[80], serverfeature[80], line[300];
	static char *proxyfeatlist = "SIZE:MDTM";

	sfputs(x, "%s", "FEAT");
	if (sfgets(x, line, sizeof(line)) == NULL) {
		syslog(LOG_NOTICE, "monitor: server not responding");
		exit (1);
		}

	rc = atoi(line);
	if (rc != 211) {
		/* kein FEAT Support */ ;
		cfputs(x, "502 command not implemented");
		return (1);
		}


	cfputs(x, "211-feature list follows");
	while (1) {
		if (sfgets(x, line, sizeof(line)) == NULL) {
			syslog(LOG_NOTICE, "lost server in FEAT response");
			exit (1);
			}
		else if (*line != ' ') { 

			/*
			 * RFC2389 specifies exactly one space in this
			 * multi-line response.  Nothing else.
			 */

			break;
			}


		/* Get feature from server response ...
		 */

		copy_string(serverfeature, line, sizeof(serverfeature));
		strupr(serverfeature);


		/* ... and compare it against our feature list
		 */


		p = proxyfeatlist;
		while (*get_quoted(&p, ':', word, sizeof(word)) != 0) {
			if (strcmp(word, serverfeature) == 0) {
				snprintf (line, sizeof(line) - 4, " %s", word);
				cfputs(x, line);
				break;
				}
			}
		}

	cfputs(x, "211 end");
	return (0);
}

int setvar(ftp_t *x, char *var, char *value)
{
	char	varname[200];

	#if defined SOLARIS
	snprintf (varname, sizeof(varname) - 2, "%s%s=%s", x->config->varname, var, value != NULL? value: "");
	putenv(varname);
	#else
	snprintf (varname, sizeof(varname) - 2, "%s%s", x->config->varname, var);
	setenv(varname, value != NULL? value: "", 1);
	#endif

	return (0);
}

int set_variables(ftp_t *x)
{
	char	val[200];

	setvar(x, "INTERFACE", x->interface);
	snprintf (val, sizeof(val) - 2, "%u", x->port);
	setvar(x, "PORT", val);

	setvar(x, "CLIENT", x->client_ip);
	setvar(x, "CLIENTNAME", x->client);

	setvar(x, "SERVER", x->server.ipnum);
	snprintf (val, sizeof(val) - 2, "%u", x->server.port);
	setvar(x, "SERVERPORT", val);

	setvar(x, "SERVERNAME", x->server.name);
	setvar(x, "SERVERLOGIN", x->username);
	setvar(x, "USERNAME", x->local.username);
	setvar(x, "PASSWD", x->local.password);

	return (0);
}

int run_acp(ftp_t *x)
{
	int	rc, pid, pfd[2];
	char	line[300];
	
	if (*x->config->acp == 0)
		return (0);

	rc = 0;
	if (pipe(pfd) != 0) {
		syslog(LOG_NOTICE, "-ERR: can't pipe: %s", strerror(errno));
		exit (1);
		}
	else if ((pid = fork()) < 0) {
		syslog(LOG_NOTICE, "-ERR: can't fork acp: %s", strerror(errno));
		exit (1);
		}
	else if (pid == 0) {
		int	argc;
		char	*argv[32];

		close(0);		/* Das acp kann nicht vom client lesen. */
		dup2(pfd[1], 2);	/* stderr wird vom parent gelesen. */
		close(pfd[0]);
		set_variables(x);
		
		copy_string(line, x->config->acp, sizeof(line));
		argc = split(line, argv, ' ', 30);
		argv[argc] = NULL;
		execvp(argv[0], argv);

		syslog(LOG_NOTICE, "-ERR: can't exec acp %s: %s", argv[0], strerror(errno));
		exit (1);
		}
	else {
		int	len;
		char	message[300];

		close(pfd[1]);
		*message = 0;
		if ((len = read(pfd[0], message, sizeof(message) - 2)) < 0)
			len = 0;

		message[len] = 0;
		noctrl(message);
		close(pfd[0]);

		if (waitpid(pid, &rc, 0) < 0) {
			syslog(LOG_NOTICE, "-ERR: error while waiting for acp: %s", strerror(errno));
			exit (1);
			}

		rc = WIFEXITED(rc) != 0? WEXITSTATUS(rc): 1;
		if (*message == 0)
			copy_string(message, rc == 0? "access granted": "access denied", sizeof(message));

		if (*message != 0)
			syslog(LOG_NOTICE, "%s (rc= %d)", message, rc);
		}
		
	return (rc);
}

static char *getvarname(char **here, char *var, int size)
{
	int	c, k;

	size = size - 2;
	k = 0;
	while ((c = **here) != 0) {
		*here += 1;
		if (c == ' '  ||  c == '\t'  ||  c == '=')
			break;

		if (k < size)
			var[k++] = c;
		}

	var[k] = 0;
	strupr(var);
	*here = skip_ws(*here);

	return (var);
}