implement Transport; include "common.m";include "transport.m"; # local copies from CUsys: Sys;U: Url;	Parsedurl: import U;S: String;CU: CharonUtils;	Netconn, ByteSource, Header, config: import CU; FTPPORT: con 21; # Return codesExtra, Success, Incomplete, TempFail, PermFail : con (1+iota); cmdbuf := array[200] of byte;dbg := 0; init(c: CharonUtils){	CU = c;	sys = load Sys Sys->PATH;	S = load String String->PATH;	U = load Url Url->PATH;	if (U != nil)		U->init();	dbg = int (CU->config).dbg['n'];} connect(nc: ref Netconn, bs: ref ByteSource){	port := nc.port;	if(port == 0)		port = FTPPORT;	addr := "tcp!" + nc.host + "!" + string port;	if(dbg)		sys->print("ftp %d: dialing %s\n", nc.id, addr);	err := "";	ctlfd : ref sys->FD = nil;	rv : int;	(rv, nc.conn) = sys->dial(addr, nil);	if(rv < 0) {		syserr := sys->sprint("%r");		if(S->prefix("cs: dialup", syserr))			err = syserr[4:];		else if(S->prefix("cs: dns: no translation found", syserr))			err = "unknown host";		else			err = sys->sprint("couldn't connect: %s", syserr);	}	else {		if(dbg)			sys->print("ftp %d: connected\n", nc.id);		ctlfd = nc.conn.dfd;		# use cfd to hold control connection so can use dfd to hold data connection		nc.conn.cfd = ctlfd;		nc.conn.dfd = nil; 		# look for Hello		(code, msg) := getreply(nc, ctlfd);		if(code != Success)			err = "instead of hello: " + msg;		else {			# logon			err = sendrequest(nc, ctlfd, "USER anonymous");			if(err == "") {				(code, msg) = getreply(nc, ctlfd);				if(code == Incomplete) {					# need password					err = sendrequest(nc, ctlfd, "PASS webget@webget.com");					if(err == "")						(code, msg) = getreply(nc, ctlfd);				}				if(err == "") {					if(code != Success)						err =  "login failed: " + msg; 					# image type					err = sendrequest(nc, ctlfd, "TYPE I");					if(err == "") {						(code, msg) = getreply(nc, ctlfd);						if(code != Success)							err =  "can't set type I: " + msg;					}				}			}		}	}	if(err == "") {		nc.connected = 1;		nc.state = CU->NCgethdr;	}	else {		if(dbg)			sys->print("ftp %d: connection failed: %s\n", nc.id, err);		bs.err = err;		closeconn(nc);	}} # Ask ftp server on ctlfd for passive port and dial itdialdata(nc: ref Netconn, ctlfd: ref sys->FD) : string{	# put in passive mode	sendrequest(nc, ctlfd, "PASV");	(code, msg) := getreply(nc, ctlfd);	if(code != Success)		return "can't use passive mode: " + msg;	(paddr, pport) := passvap(msg);	if(paddr == "")		return "passive mode protocol botch: " + msg;	# dial data port	daddr := "tcp!" + paddr + "!" + pport;	if(dbg)		sys->print("ftp %d: dialing data %s", nc.id, daddr);	(ok, dnet) := sys->dial(daddr, nil);	if(ok < 0)		return "data dial error";	nc.conn.dfd = dnet.dfd;	return "";} writereq(nc: ref Netconn, bs: ref ByteSource){	ctlfd := nc.conn.cfd;	CU->assert(ctlfd != nil);	err := dialdata(nc, ctlfd);	if(err == "") {		# tell remote to send file		err = sendrequest(nc, ctlfd, "RETR " + bs.req.url.path);	}	if(err != "") {		if(dbg)			sys->print("ftp %d: error: %s\n", nc.id, err);		bs.err = err;		closeconn(nc);	}} gethdr(nc: ref Netconn, bs: ref ByteSource){	hdr := Header.new();	bs.hdr = hdr;	err := "";	ctlfd := nc.conn.cfd;	dfd := nc.conn.dfd;	CU->assert(ctlfd != nil && dfd != nil);	(code, msg) := getreply(nc, ctlfd);	if(code != Extra) {		if(dbg)			sys->print("ftp %d: retrieve failed: %s\n",				nc.id, msg);		hdr.code = CU->HCNotFound;		hdr.msg = "Not found";	}	else {		hdr.code = CU->HCOk; 		# try to guess media type before returning header		buf := array[sys->ATOMICIO] of byte;		n := sys->read(dfd, buf, len buf);		if(dbg)			sys->print("ftp %d: read %d bytes\n", nc.id, n);		if(n < 0)			err = "error reading data";		else {			if(n > 0)				nc.tbuf = buf[0:n];			else				nc.tbuf = nil;			hdr.setmediatype(bs.req.url.path, nc.tbuf);			hdr.actual = bs.req.url;			hdr.base = hdr.actual;			hdr.length = -1;			hdr.msg = "Ok";		}	}	if(err != "") {		if(dbg)			sys->print("ftp %d: error %s\n", nc.id, err);		bs.err = err;		closeconn(nc);	}} getdata(nc: ref Netconn, bs: ref ByteSource): int{	dfd := nc.conn.dfd;	CU->assert(dfd != nil);	if (bs.data == nil || bs.edata >= len bs.data) {		closeconn(nc);		return 0;	}	buf := bs.data[bs.edata:];	n := len buf;	if (nc.tbuf != nil) {		# initial overread of header		if (n >= len nc.tbuf) {			n = len nc.tbuf;			buf[:] = nc.tbuf;			nc.tbuf = nil;			return n;		}		buf[:] = nc.tbuf[:n];		nc.tbuf = nc.tbuf[n:];		return n;	}	n = sys->read(dfd, buf, n);	if(dbg > 1)		sys->print("ftp %d: read %d bytes\n", nc.id, n);	if(n <= 0) {		bs.err = "eof";		closeconn(nc);	}	return n;} # Send ftp request cmd along fd; return "" if OK else error string.sendrequest(nc: ref Netconn, fd: ref sys->FD, cmd: string) : string{	if(dbg > 1)		sys->print("ftp %d: send request: %s\n", nc.id, cmd);	cmd = cmd + "\r\n";	buf := array of byte cmd;	n := len buf;	if(sys->write(fd, buf, n) != n)		return sys->sprint("write error: %r");	return "";} # Get reply to ftp request along fd.# Reply may be more than one line ("commentary")# but ends with a line that has a status code in the first# three characters (a number between 100 and 600)# followed by a blank and a possible message.# If OK, return the hundreds digit of the status (which will# mean one of Extra, Success, etc.), and the whole# last line; else return (-1, "").getreply(nc: ref Netconn, fd: ref sys->FD) : (int, string){	# Reply might contain more than one line,	# because there might be "commentary" lines.	i := 0;	j := 0;	aline: array of byte;	eof := 0;	for(;;) {		(aline, eof, i, j) = CU->getline(fd, cmdbuf, i, j);		if(eof)			break;		line := string aline;		n := len line;		if(n == 0)			break;		if(dbg > 1)			sys->print("ftp %d: got reply: %s\n", nc.id, line);		rv := int line;		if(rv >= 100 && rv < 600) {			# if line is like '123-stuff'			# then there will be more lines until			# '123 stuff'			if(len line<4 || line[3]==' ')				return (rv/100, line);		}	}	return (-1, "");} # Parse reply to PASSV to find address and port numbers.# This is AI because extant agents aren't good at following# the standard.passvap(s: string) : (string, string){	addr := "";	port := "";	(nil, v) := S->splitl(s, "(");	if(v != "")		s = v[1:];	else		(nil, s) = S->splitl(s, "0123456789");	if(s != "") {		(n, l) := sys->tokenize(s, ",");		if(n >= 6) {			addr = hd l + ".";			l = tl l;			addr += hd l + ".";			l = tl l;			addr += hd l + ".";			l = tl l;			addr += hd l;			l = tl l;			p1 := int hd l;			p2 := int hd tl l;			port = string (((p1&255)<<8)|(p2&255));		}	}	return (addr, port);} defaultport(nil: string) : int{	return FTPPORT;} closeconn(nc: ref Netconn){	nc.conn.dfd = nil;	nc.conn.cfd = nil;	nc.conn.dir = "";	nc.connected = 0;}