/*
 * Copyright (c) 1989 Jan-Simon Pendry
 * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)info_hes.c	8.1 (Berkeley) 6/6/93
 *	$Id: info_hes.c,v 1.12 2003/06/02 23:36:51 millert Exp $
 */

/*
 * Get info from Hesiod
 *
 * Zone transfer code from Bruce Cole <cole@cs.wisc.edu>
 */

#include "am.h"

#ifdef HAS_HESIOD_MAPS
#include <hesiod.h>

#define	HES_PREFIX	"hesiod."
#define	HES_PREFLEN	7

#ifdef HAS_HESIOD_RELOAD
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/uio.h>
#include <netdb.h>

/*
 * Patch up broken system include files
 */
#ifndef C_HS
#define C_HS	4
#endif
#ifndef T_TXT
#define	T_TXT	16
#endif

static int soacnt;
static struct timeval hs_timeout;
static int servernum;
#endif /* HAS_HESIOD_RELOAD */

/*
 * No easy way to probe the server - check the map name begins with "hesiod."
 */
int
hesiod_init(char *map, time_t *tp)
{
#ifdef DEBUG
	dlog("hesiod_init(%s)", map);
#endif
	*tp = 0;
	return strncmp(map, HES_PREFIX, HES_PREFLEN) == 0 ? 0 : ENOENT;
}


/*
 * Make Hesiod name.  Skip past the "hesiod."
 * at the start of the map name and append
 * ".automount".  The net effect is that a lookup
 * of /defaults in hesiod.home will result in a
 * call to hes_resolve("/defaults", "home.automount");
 */
#ifdef notdef
#define MAKE_HES_NAME(dest, src) snprintf(dest, sizeof(dest), \
    "%s%s", src + HES_PREFLEN, ".automount")
#endif

/*
 * Do a Hesiod nameserver call.
 * Modify time is ignored by Hesiod - XXX
 */
int
hesiod_search(mnt_map *m, char *map, char **pval, time_t *tp)
{
	int error;
	char hes_key[MAXPATHLEN];
	char **rvec;

#ifdef DEBUG
	dlog("hesiod_search(m=%x, map=%s, key=%s, pval=%x tp=%x)",
	    m, map, key, pval, tp);
#endif
	/*MAKE_HES_NAME(hes_map, map);*/
	snprintf(hes_key, sizeof(hes_key), "%s.%s", key, map+HES_PREFLEN);

	/*
	 * Call the resolver
	 */
#ifdef DEBUG
	dlog("hesiod_search: hes_resolve(%s, %s)", hes_key, "automount");
#ifdef HAS_HESIOD_RELOAD
	if (debug_flags & D_FULL)
		_res.options |= RES_DEBUG;
#endif
#endif
	rvec = hes_resolve(hes_key, "automount");
	/*
	 * If a reply was forthcoming then return
	 * it (and free subsequent replies)
	 */
	if (rvec && *rvec) {
		*pval = *rvec;
		while (*++rvec)
			free(*rvec);
		return 0;
	}

	/*
	 * Otherwise reflect the hesiod error into a Un*x error
	 */
#ifdef DEBUG
	dlog("hesiod_search: Error: %d", hes_error());
#endif
	switch (hes_error()) {
	case HES_ER_NOTFOUND:	error = ENOENT; break;
	case HES_ER_CONFIG:	error = EIO; break;
	case HES_ER_NET:	error = ETIMEDOUT; break;
	default:		error = EINVAL; break;
	}
#ifdef DEBUG
	dlog("hesiod_search: Returning: %d", error);
#endif
	return error;
}

#ifdef HAS_HESIOD_RELOAD
/*
 * Zone transfer...
 */

#define MAXHSNS 8
#define MAX_NSADDR 16

static char *hs_domain;
static mnt_map *hs_map;
static int hs_nscount;
static char nsaddr_list[MAX_NSADDR][sizeof(struct in_addr)];

int
hesiod_reload(mnt_map *m, char *map, void (*fn)())
{
	char *zone_name, *cp;
	short domainlen;
	int status;

#ifdef DEBUG
	dlog("hesiod_reload (%x %s %x)", m, map, fn);
#endif /* DEBUG */
	if (status = res_init()) {
#ifdef DEBUG
		dlog("hesiod_reload: res_init failed with %d", status);
#endif
		return(status);
	}
	_res.retrans = 90;
	hs_map = m;
	domainlen = strlen(hostdomain);
	zone_name = hes_to_bind(map+HES_PREFLEN, "automount");
	if (*zone_name == '.')
		zone_name++;
	hs_domain = zone_name;
	/* Traverse the DNS tree until we find an SOA we can transfer from.
	 (Our initial zone_name is likely to just be a subtree of a
	 real zone). */
	do {
		/* If we can't find any NS records, go up a level in the
		   DNS tree */
		if (hs_get_ns_list(zone_name) == 0 &&
		    hs_zone_transfer(zone_name) == 0)
			return(0);
		/* Move up DNS tree by one component */
		if (cp = strchr(zone_name, '.'))
			zone_name = ++cp;
		else
			break;
	} while (strlen(zone_name) >= domainlen);
#ifdef DEBUG
	dlog("hesiod_reload: Giving up on %s", hs_domain);
#endif
	return(-1);
}

int
hs_zone_transfer(char *domain)
{
	int status, len;
	char buf[PACKETSZ];
	/* Want to make sure ansbuf is well alligned */
	u_int32_t ansbuf[PACKETSZ/sizeof(u_int32_t)];

#ifdef DEBUG
	dlog("hs_zone_transfer (%s)", domain);
#endif
	if ((len = res_mkquery(QUERY, domain, C_HS, T_AXFR,
	    (char *)NULL, 0, NULL, buf, PACKETSZ)) == -1) {
#ifdef DEBUG
		dlog("hs_zone_transfer: res_mkquery failed");
#endif
		errno = 0;
		return(-1);
	}
	if ((status = hs_res_send(buf, len, (char *)ansbuf, PACKETSZ)) == -1) {
#ifdef DEBUG
	    dlog("hs_zone_transfer: hs_res_send failed.  status %d errno %d",
		 status, errno);
#endif
		errno = 0;
		return(-1);
	}
	return(0);
}

#define hs_server_addr(ns) ((struct in_addr *) nsaddr_list[ns])

int
hs_res_send(char *buf, int buflen, char *answer, int anslen)
{
	int retry, ns;
	u_short id, len;
	HEADER *hp = (HEADER *) buf;
	struct iovec iov[2];
	static int s = -1;
	int status;
	struct sockaddr_in server;

	soacnt = 0;
	id = hp->id;
	/*
	 * Send request, RETRY times, or until successful
	 */
	for (retry = _res.retry; retry > 0; retry--) {
		for (ns = 0; ns < hs_nscount; ns++) {
			hs_timeout.tv_sec =
				(_res.retrans << (_res.retry - retry))
				/ hs_nscount;
			if (hs_timeout.tv_sec <= 0)
				hs_timeout.tv_sec = 1;
			hs_timeout.tv_usec = 0;
			if (s < 0) {
				s = socket(AF_INET, SOCK_STREAM, 0);
				if (s < 0) {
					continue;
				}
				servernum = ns;
				bcopy(hs_server_addr(ns), &server.sin_addr,
				    sizeof(struct in_addr));
				server.sin_family = AF_INET;
				server.sin_port = htons(NAMESERVER_PORT);

				if (connect(s, &server,
					    sizeof(struct sockaddr)) < 0) {
					(void) close(s);
					s = -1;
					continue;
				}
			}
			/*
			 * Send length & message
			 */
			len = htons((u_short)buflen);
			iov[0].iov_base = (caddr_t)&len;
			iov[0].iov_len = sizeof(len);
			iov[1].iov_base = buf;
			iov[1].iov_len = buflen;
			if (writev(s, iov, 2) != sizeof(len) + buflen) {
				(void) close(s);
				s = -1;
				continue;
			}
			status = 0;
			while (s != -1 && soacnt < 2 && status != -2) {
				if ((status =
				    hs_readresp(s, answer, anslen)) == -1) {
					(void) close(s);
					s = -1;
					continue;
				}
			}
			if (status == -2) {
				/* There was a permanent error transfering this
				   zone.  Give up. */
				if (s != -1) {
					(void) close(s);
					s = -1;
				}
				return(-1);
			}
			if (s == -1)
				continue;
			return (0);
		}
	}
	if (errno == 0)
		errno = ETIMEDOUT;
	return (-1);
}

/* Returns:
   0: Success
   -1: Error
   -2: Permanent failure
*/
int
hs_readresp(int s, char *answer, int anslen)
{
	int len, n;
	char *cp;

	cp = answer;
	len = sizeof(short);
	while (len != 0 &&
	    (n = hs_res_vcread(s, (char *)cp, (int)len, &hs_timeout)) > 0) {
		cp += n;
		len -= n;
	}
	if (n <= 0)
		return(-1);
	cp = answer;
	if ((len = _getshort(cp)) > anslen) {
#ifdef DEBUG
		dlog("hs_readresp: response too long: %d", len);
#endif
		return(-1);
	}
	while (len != 0 &&
	    (n = hs_res_vcread(s, (char *)cp, (int)len, &hs_timeout)) > 0) {
		cp += n;
		len -= n;
	}
	if (n <= 0)
		return(-1);
	return(hs_parse(answer, answer+PACKETSZ));
}

int
hs_res_vcread(int sock, char *buf, int buflen, struct timeval *timeout)
{
	int n;

	if ((n = hs_res_selwait(sock, timeout)) > 0)
		return(read(sock, buf, buflen));
	else
		return(n);
}

int
hs_res_selwait(int sock, struct timeval timeout)
{
	fd_set *fdsp;
	int fdsn;
	int n;

	/*
	 * Wait for reply
	 */
	fdsn = howmany(sock+1, NFDBITS) * sizeof(fd_mask);
	if ((fdsp = (fd_set *)malloc(fdsn)) == NULL)
		return(0);
	memset(fdsp, 0, fdsn);

	FD_SET(sock, fdsp);
	n = select(sock+1, fdsp, NULL, NULL, timeout);
	free(fdsp);
	return(n);
}

/* Returns:
   0: Success
   -1: Error
   -2: Permanent failure
*/
int
hs_parse(char *msg, char *eom)
{
	char *cp;
	HEADER *hp;
	int n, len;
	int qdcount, ancount;
	char key[PACKETSZ];
	char *key_cpy, *value, *hs_make_value();
	int16_t type;

	hp = (HEADER *)msg;
	if (hp->rcode != NOERROR || hp->opcode != QUERY) {
		char dq[20];
#ifdef DEBUG
		dlog("Bad response (%d) from nameserver %s",
		    hp->rcode, inet_dquad(dq, sizeof(dq),
		    hs_server_addr(servernum)->s_addr));
#endif /* DEBUG */
		return(-1);
	}
	cp = msg + sizeof(HEADER);
	ancount = ntohs(hp->ancount);
	qdcount = ntohs(hp->qdcount);
	while (qdcount-- > 0)
		cp += dn_skipname(cp, eom) + QFIXEDSZ;
	if (soacnt == 0 && ancount == 0) {
		/* XXX We should look for NS records to find SOA */
#ifdef DEBUG
		dlog("No SOA found");
#endif
		return(-2);
	}
	while (ancount-- > 0 && cp < eom) {
		if ((n = dn_expand(msg, eom, cp, key, PACKETSZ)) < 0)
			break;
		cp += n;
		if ((type = _getshort(cp)) == T_SOA) {
			soacnt++;
		}
		cp += 2*sizeof(u_int16_t) + sizeof(u_int32_t);
		len = _getshort(cp);
		cp += sizeof(u_int16_t);
		/* Check to see if key is in our domain */
		if (type == T_TXT && hs_strip_our_domain(key)) {
			value = hs_make_value(cp, len);
			if (value == NULL)
				return(-1);
			key_cpy = strdup(key);
#ifdef DEBUG
			dlog("hs_parse: Parsed key: %s, value: %s", key,
			    value);
#endif
			mapc_add_kv(hs_map, key_cpy, value);
		}
		cp += len;
		errno = 0;
	}
	return(0);
}

/* Check to see if the domain name in the supplied argument matches
   hs_domain.  Strip hs_domain from supplied argument if so. */
int
hs_strip_our_domain(char *name)
{
	char *end_pos;
	short targ_len, cur_len;

	targ_len = strlen(hs_domain);
	cur_len = strlen(name);
	if (cur_len <= targ_len)
		return(0);
	end_pos = &name[cur_len - targ_len];
	if (strcmp(end_pos, hs_domain) != 0)
		return(0);
	if (*--end_pos != '.')
		return(0);
	*end_pos = '\0';
	return(1);
}

#define MAXDATA 8*1024

char *
hs_make_value(chr *cp, int len)
{
	char *value, *cpcpy, *valuep;
	int cnt, nextcnt, totalcnt, lencpy;
#ifdef DEBUG
	char *dbgname;

	dbgname = &cp[1];
#endif /* DEBUG */

	lencpy = len;
	cpcpy = cp;
	totalcnt = 0;
	cnt = *cpcpy++;
	while (cnt) {
		totalcnt += cnt;
		lencpy -= cnt+1;
		if (lencpy == 0)
			break;
		nextcnt = cpcpy[cnt];
		cpcpy = &cpcpy[cnt+1];
		cnt = nextcnt;
	}
	if (totalcnt < 1 || totalcnt > MAXDATA || totalcnt > len) {
#ifdef DEBUG
		dlog("TXT RR not of expected length (%d %d): %s", totalcnt,
		    len, dbgname);
#endif /* DEBUG */
		return(NULL);
	}
	/* Allocate null terminated string */
	value = (char *) xmalloc(totalcnt+1);
	value[totalcnt] = '\0';
	cnt = *cp++;
	valuep = value;
	while (cnt) {
		bcopy(cp, valuep, cnt);
		len -= cnt+1;
		if (len == 0)
			break;
		valuep = &valuep[cnt];
		nextcnt = cp[cnt];
		cp = &cp[cnt+1];
		cnt = nextcnt;
	}
	return(value);
}

int
hs_make_ns_query(char *domain, char *ansbuf)
{
	int status, len;
	char buf[PACKETSZ];

	if ((len = res_mkquery(QUERY, domain, C_HS, T_NS,
	    (char *)NULL, 0, NULL, buf, PACKETSZ)) == -1) {
#ifdef DEBUG
		dlog("hs_get_ns_list: res_mkquery failed");
#endif
		errno = 0;
		return(-1);
	}
	if ((status = res_send(buf, len, (char *)ansbuf, PACKETSZ)) == -1) {
#ifdef DEBUG
		dlog("hs_get_ns_list: res_send failed.  status %d errno %d",
		    status, errno);
#endif
		errno = 0;
		return(-1);
	}
	return(0);
}

static void
add_address(struct in_addr *addr)
{
	char dq[20];

	bcopy((char *)addr, nsaddr_list[hs_nscount++], sizeof(struct in_addr));
#ifdef DEBUG
	dlog("Adding NS address %s", inet_dquad(dq, sizeof(dq), addr->s_addr));
#endif /* DEBUG */
}

int
hs_get_ns_list(char *domain)
{
	HEADER *hp;
	int qdcount, nscount;
	char *cp;
	int n, len;
	char key[PACKETSZ], name[PACKETSZ], msg[PACKETSZ], *eom;
	u_int32_t **hptr;
	struct hostent *ghp;
	int numns;
	char nsname[MAXHSNS][MAXDATA];
	int nshaveaddr[MAXHSNS], i;
	short type;

	if (hs_make_ns_query(domain, msg) == -1)
		return(-1);
	numns = hs_nscount = 0;
	eom = &msg[PACKETSZ];
	bzero(nsname, sizeof(nsname));
	hp = (HEADER *)msg;
	if (hp->rcode != NOERROR || hp->opcode != QUERY) {
#ifdef DEBUG
		dlog("Bad response (%d) from nameserver %#x", hp->rcode,
		    hs_server_addr(servernum)->s_addr);
#endif /* DEBUG */
		return(-1);
	}
	cp = msg + sizeof(HEADER);
	qdcount = ntohs(hp->qdcount);
	while (qdcount-- > 0)
		cp += dn_skipname(cp, eom) + QFIXEDSZ;
	nscount = ntohs(hp->ancount) + ntohs(hp->nscount) + ntohs(hp->arcount);
#ifdef DEBUG
	dlog("hs_get_ns_list: Processing %d response records", nscount);
#endif
	for (;nscount; nscount--) {
		if ((n = dn_expand(msg, eom, cp, key, PACKETSZ)) < 0)
			break;
		cp += n;
		type = _getshort(cp);
		cp += 2*sizeof(u_short) + sizeof(u_int32_t);
		len = _getshort(cp);
		cp += sizeof(u_short);
#ifdef DEBUG
		dlog("hs_get_ns_list: Record type: %d", type);
#endif
		switch (type) {
		case T_NS:
			if (numns >= MAXHSNS || strcasecmp(domain, key) != 0)
				break;
			if ((n = dn_expand(msg, eom, cp, name, PACKETSZ)) < 0)
				break;
#ifdef DEBUG
			dlog("hs_get_ns_list: NS name: %s", name);
#endif
			for (i = 0; i < numns; i++)
				if (strcasecmp(nsname[i], name) == 0)
					break;
			if (i == numns) {
#ifdef DEBUG
				dlog("hs_get_ns_list: Saving name %s", name);
#endif
				strlcpy(nsname[numns], name,
				    sizeof(nsname[numns]));
				nshaveaddr[numns] = 0;
				numns++;
			}
			break;
		case T_A:
			if (hs_nscount == MAX_NSADDR)
				break;
			for (i = 0; i < numns; i++) {
				if (strcasecmp(nsname[i], domain) == 0) {
					nshaveaddr[i]++;
					add_address((struct in_addr *) cp);
					break;
				}
			}
			break;
		default:
			break;
		}
		if (hs_nscount == MAX_NSADDR)
			break;
		cp += len;
		errno = 0;
	}
#ifdef  DEBUG
	dlog("hs_get_ns_list: Found %d NS records", numns);
#endif
	for (i = 0; i < numns; i++) {
		if (nshaveaddr[i])
			continue;
		if ((ghp = gethostbyname(nsname[i])) == 0)
			continue;
		for (hptr = (in_addr_t **)ghp->h_addr_list;
		    *hptr && hs_nscount < MAX_NSADDR; hptr++) {
			add_address((struct in_addr *) *hptr);
		}
	}
	if (hs_nscount)
		return(0);
#ifdef DEBUG
	dlog("No NS records found for %s", domain);
	return(-1);
#endif /* DEBUG */
}
#endif /* HAS_HESIOD_RELOAD */
#endif /* HAS_HESIOD_MAPS */