/*  * 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 <bio.h>#include <ndb.h>#include <fcall.h> enum{	Maxpath=	128,}; typedef struct Endpoints Endpoints;struct Endpoints{	char 	*net;	char	*lsys;	char	*lserv;	char	*rsys;	char	*rserv;}; void		xfer(int, int);void		xfer9p(int, int);Endpoints*	getendpoints(char*);void		freeendpoints(Endpoints*);char*		iptomac(char*, char*);int		macok(char*); voidusage(void){	fprint(2, "usage: trampoline [-9] [-a addr] [-m netdir] addr\n");	exits("usage");} voidmain(int argc, char **argv){	char *altaddr, *checkmac, *mac;	int fd, fd0, fd1;	void (*x)(int, int);	Endpoints *ep; 	checkmac = nil;	altaddr = nil;	x = xfer;	ARGBEGIN{	case '9':		x = xfer9p;		break;	case 'a':		altaddr = EARGF(usage());		break;	case 'm':		checkmac = EARGF(usage());		break;	default:		usage();	}ARGEND; 	if(argc != 1)		usage(); 	if(checkmac){		ep = getendpoints(checkmac);		mac = iptomac(ep->rsys, ep->net);		if(!macok(mac)){			syslog(0, "trampoline", "badmac %s from %s!%s for %s!%s on %s",				mac, ep->rsys, ep->rserv, ep->lsys, ep->lserv, ep->net);			exits("bad mac");		}	}		fd0 = 0;	fd1 = 1;	if(altaddr){		fd0 = dial(altaddr, 0, 0, 0);		if(fd0 < 0)			sysfatal("dial %s: %r", altaddr);		fd1 = fd0;	}	fd = dial(argv[0], 0, 0, 0);	if(fd < 0)		sysfatal("dial %s: %r", argv[0]); 	rfork(RFNOTEG);	switch(fork()){	case -1:		fprint(2, "%s: fork: %r\n", argv0);		exits("dial");	case 0:		(*x)(fd0, fd);		break;	default:		(*x)(fd, fd1);		break;	}	postnote(PNGROUP, getpid(), "die yankee pig dog");	exits(0);} voidxfer(int from, int to){	char buf[12*1024];	int n; 	while((n = read(from, buf, sizeof buf)) > 0)		if(write(to, buf, n) < 0)			break;} voidxfer9p(int from, int to){	uchar *buf;	uint nbuf;	int n; 	nbuf = 256;	buf = malloc(nbuf);	if(buf == nil)		sysfatal("xfer: malloc %ud: %r", nbuf); 	for(;;){		if(readn(from, buf, 4) != 4)			break;		n = GBIT32(buf);		if(n > nbuf){			nbuf = n+8192;			buf = realloc(buf, nbuf);			if(buf == nil)				sysfatal("xfer: realloc %ud: %r", nbuf);		}		if(readn(from, buf+4, n-4) != n-4)			break;		if(write(to, buf, n) != n){			sysfatal("oops: %r");			break;		}	}} voidgetendpoint(char *dir, char *file, char **sysp, char **servp){	int fd, n;	char buf[Maxpath];	char *sys, *serv; 	sys = serv = 0; 	snprint(buf, sizeof buf, "%s/%s", dir, file);	fd = open(buf, OREAD);	if(fd >= 0){		n = read(fd, buf, sizeof(buf)-1);		if(n>0){			buf[n-1] = 0;			serv = strchr(buf, '!');			if(serv){				*serv++ = 0;				serv = strdup(serv);			}			sys = strdup(buf);		}		close(fd);	}	if(serv == 0)		serv = strdup("unknown");	if(sys == 0)		sys = strdup("unknown");	*servp = serv;	*sysp = sys;} Endpoints *getendpoints(char *dir){	Endpoints *ep;	char *p; 	ep = malloc(sizeof(*ep));	ep->net = strdup(dir);	p = strchr(ep->net+1, '/');	if(p == nil){		free(ep->net);		ep->net = "/net";	} else		*p = 0;	getendpoint(dir, "local", &ep->lsys, &ep->lserv);	getendpoint(dir, "remote", &ep->rsys, &ep->rserv);	return ep;} voidfreeendpoints(Endpoints *ep){	free(ep->lsys);	free(ep->rsys);	free(ep->lserv);	free(ep->rserv);	free(ep);} char*iptomac(char *ip, char *net){	char file[Maxpath];	Biobuf *b;	char *p;	char *f[5]; 	snprint(file, sizeof(file), "%s/arp", net);	b = Bopen(file, OREAD);	if(b == nil)		return nil;	while((p = Brdline(b, '\n')) != nil){		p[Blinelen(b)-1] = 0;		if(tokenize(p, f, nelem(f)) < 4)			continue;		if(strcmp(f[1], "OK") == 0		&& strcmp(f[2], ip) == 0){			p = strdup(f[3]);			Bterm(b);			return p;		}	}	Bterm(b);	return nil;} intmacok(char *mac){	char *p; 	if(mac == nil)		return 0;	free(p = csgetvalue("/net", "ether", mac, "trampok", nil));	return !(p == nil);}