#include <u.h>#include <libc.h>#include <auth.h>#include "authlocal.h" static char *ccmsg = "can't connect to AS"; intauthenticate(int fd, int afd){	int rv;	char trbuf[TICKREQLEN];	char tbuf[2*TICKETLEN]; 	if(fsession(fd, trbuf) < 0){		werrstr("fsession: %r");		return -1;	} 	/* no authentication required? */	memset(tbuf, 0, 2*TICKETLEN);	if(trbuf[0] == 0)		return 0; 	/* get a ticket from an auth server */	if(afd < 0){		afd = authdial();		if(afd < 0){			werrstr(ccmsg);			return -1;		}		rv = _asgetticket(afd, trbuf, tbuf);		close(afd);	} else		rv = _asgetticket(afd, trbuf, tbuf);	if(rv < 0)		return -1; 	/* pass ticket to kernel */	return fauth(fd, tbuf);}