/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <ctype.h> static int	nettrans(char*, char*, int na, char*, int); enum{	Maxpath=	256,}; /* *  announce a network service. */intannounce(char *addr, char *dir){	int ctl, n, m;	char buf[Maxpath];	char buf2[Maxpath];	char netdir[Maxpath];	char naddr[Maxpath];	char *cp; 	/*	 *  translate the address	 */	if(nettrans(addr, naddr, sizeof(naddr), netdir, sizeof(netdir)) < 0)		return -1; 	/*	 * get a control channel	 */	ctl = open(netdir, ORDWR);	if(ctl<0){		werrstr("announce opening %s: %r", netdir);		return -1;	}	cp = strrchr(netdir, '/');	if(cp == nil){		werrstr("announce arg format %s", netdir);		close(ctl);		return -1;	}	*cp = 0; 	/*	 *  find out which line we have	 */	n = snprint(buf, sizeof(buf), "%s/", netdir);	m = read(ctl, &buf[n], sizeof(buf)-n-1);	if(m <= 0){		werrstr("announce reading %s: %r", netdir);		close(ctl);		return -1;	}	buf[n+m] = 0; 	/*	 *  make the call	 */	n = snprint(buf2, sizeof(buf2), "announce %s", naddr);	if(write(ctl, buf2, n)!=n){		werrstr("announce writing %s: %r", netdir);		close(ctl);		return -1;	} 	/*	 *  return directory etc.	 */	if(dir){		strncpy(dir, buf, NETPATHLEN);		dir[NETPATHLEN-1] = 0;	}	return ctl;} /* *  listen for an incoming call */intlisten(char *dir, char *newdir){	int ctl, n, m;	char buf[Maxpath];	char *cp; 	/*	 *  open listen, wait for a call	 */	snprint(buf, sizeof(buf), "%s/listen", dir);	ctl = open(buf, ORDWR);	if(ctl < 0){		werrstr("listen opening %s: %r", buf);		return -1;	} 	/*	 *  find out which line we have	 */	strncpy(buf, dir, sizeof(buf) - 1);	buf[sizeof(buf) - 1] = 0;	cp = strrchr(buf, '/');	if(cp == nil){		close(ctl);		werrstr("listen arg format %s", dir);		return -1;	}	*++cp = 0;	n = cp-buf;	m = read(ctl, cp, sizeof(buf) - n - 1);	if(m <= 0){		close(ctl);		werrstr("listen reading %s/listen: %r", dir);		return -1;	}	buf[n+m] = 0; 	/*	 *  return directory etc.	 */	if(newdir){		strncpy(newdir, buf, NETPATHLEN);		newdir[NETPATHLEN-1] = 0;	}	return ctl; } /* *  accept a call, return an fd to the open data file */intaccept(int ctl, char *dir){	char buf[Maxpath];	char *num;	long n; 	num = strrchr(dir, '/');	if(num == nil)		num = dir;	else		num++; 	n = snprint(buf, sizeof(buf), "accept %s", num);	write(ctl, buf, n); /* ignore return value, network might not need accepts */ 	snprint(buf, sizeof(buf), "%s/data", dir);	return open(buf, ORDWR);} /* *  reject a call, tell device the reason for the rejection */intreject(int ctl, char *dir, char *cause){	char buf[Maxpath];	char *num;	long n; 	num = strrchr(dir, '/');	if(num == 0)		num = dir;	else		num++;	snprint(buf, sizeof(buf), "reject %s %s", num, cause);	n = strlen(buf);	if(write(ctl, buf, n) != n)		return -1;	return 0;} /* *  perform the identity translation (in case we can't reach cs) */static intidenttrans(char *netdir, char *addr, char *naddr, int na, char *file, int nf){	char proto[Maxpath];	char *p; 	USED(nf); 	/* parse the protocol */	strncpy(proto, addr, sizeof(proto));	proto[sizeof(proto)-1] = 0;	p = strchr(proto, '!');	if(p)		*p++ = 0; 	snprint(file, nf, "%s/%s/clone", netdir, proto);	strncpy(naddr, p, na);	naddr[na-1] = 0; 	return 1;} /* *  call up the connection server and get a translation */static intnettrans(char *addr, char *naddr, int na, char *file, int nf){	int i, fd;	char buf[Maxpath];	char netdir[Maxpath];	char *p, *p2;	long n; 	/*	 *  parse, get network directory	 */	p = strchr(addr, '!');	if(p == 0){		werrstr("bad dial string: %s", addr);		return -1;	}	if(*addr != '/'){		strncpy(netdir, "/net", sizeof(netdir));		netdir[sizeof(netdir) - 1] = 0;	} else {		for(p2 = p; *p2 != '/'; p2--)			;		i = p2 - addr;		if(i == 0 || i >= sizeof(netdir)){			werrstr("bad dial string: %s", addr);			return -1;		}		strncpy(netdir, addr, i);		netdir[i] = 0;		addr = p2 + 1;	} 	/*	 *  ask the connection server	 */	snprint(buf, sizeof(buf), "%s/cs", netdir);	fd = open(buf, ORDWR);	if(fd < 0)		return identtrans(netdir, addr, naddr, na, file, nf);	if(write(fd, addr, strlen(addr)) < 0){		close(fd);		return -1;	}	seek(fd, 0, 0);	n = read(fd, buf, sizeof(buf)-1);	close(fd);	if(n <= 0)		return -1;	buf[n] = 0; 	/*	 *  parse the reply	 */	p = strchr(buf, ' ');	if(p == 0)		return -1;	*p++ = 0;	strncpy(naddr, p, na);	naddr[na-1] = 0; 	if(buf[0] == '/'){		p = strchr(buf+1, '/');		if(p == nil)			p = buf;		else 			p++;	}	snprint(file, nf, "%s/%s", netdir, p);	return 0;}