/* $NetBSD: res_mkupdate.c,v 1.1.1.2 2012/09/09 16:08:09 christos Exp $ */

/* $NetBSD: res_mkupdate.c,v 1.1.1.2 2012/09/09 16:08:09 christos Exp $ */

/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/*! \file
* \brief
* Based on the Dynamic DNS reference implementation by Viraj Bais
* <[email protected]>
*/

#if !defined(lint) && !defined(SABER)
static const char rcsid[] = "Id: res_mkupdate.c,v 1.10 2008/12/11 09:59:00 marka Exp ";
#endif /* not lint */

#include "port_before.h"

#include <sys/types.h>
#include <sys/param.h>

#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>

#include <errno.h>
#include <limits.h>
#include <netdb.h>
#include <resolv.h>
#include <res_update.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>

#include "port_after.h"

/* Options. Leave them on. */
#define DEBUG
#define MAXPORT 1024

static int getnum_str(u_char **, u_char *);
static int gethexnum_str(u_char **, u_char *);
static int getword_str(char *, int, u_char **, u_char *);
static int getstr_str(char *, int, u_char **, u_char *);

#define ShrinkBuffer(x) if ((buflen -= x) < 0) return (-2);

/* Forward. */

int res_protocolnumber(const char *);
int res_servicenumber(const char *);

/*%
* Form update packets.
* Returns the size of the resulting packet if no error
*
* On error,
* returns
*\li -1 if error in reading a word/number in rdata
* portion for update packets
*\li -2 if length of buffer passed is insufficient
*\li -3 if zone section is not the first section in
* the linked list, or section order has a problem
*\li -4 on a number overflow
*\li -5 unknown operation or no records
*/
int
res_nmkupdate(res_state statp, ns_updrec *rrecp_in, u_char *buf, int buflen) {
ns_updrec *rrecp_start = rrecp_in;
HEADER *hp;
u_char *cp, *sp2, *startp, *endp;
int n, i, soanum, multiline;
ns_updrec *rrecp;
struct in_addr ina;
struct in6_addr in6a;
char buf2[MAXDNAME];
u_char buf3[MAXDNAME];
int section, numrrs = 0, counts[ns_s_max];
u_int16_t rtype, rclass;
u_int32_t n1, rttl;
u_char *dnptrs[20], **dpp, **lastdnptr;
int siglen, keylen, certlen;

/*
* Initialize header fields.
*/
if ((buf == NULL) || (buflen < HFIXEDSZ))
return (-1);
memset(buf, 0, HFIXEDSZ);
hp = (HEADER *) buf;
statp->id = res_nrandomid(statp);
hp->id = htons(statp->id);
hp->opcode = ns_o_update;
hp->rcode = NOERROR;
cp = buf + HFIXEDSZ;
buflen -= HFIXEDSZ;
dpp = dnptrs;
*dpp++ = buf;
*dpp++ = NULL;
lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];

if (rrecp_start == NULL)
return (-5);
else if (rrecp_start->r_section != S_ZONE)
return (-3);

memset(counts, 0, sizeof counts);
for (rrecp = rrecp_start; rrecp; rrecp = NEXT(rrecp, r_glink)) {
numrrs++;
section = rrecp->r_section;
if (section < 0 || section >= ns_s_max)
return (-1);
counts[section]++;
for (i = section + 1; i < ns_s_max; i++)
if (counts[i])
return (-3);
rtype = rrecp->r_type;
rclass = rrecp->r_class;
rttl = rrecp->r_ttl;
/* overload class and type */
if (section == S_PREREQ) {
rttl = 0;
switch (rrecp->r_opcode) {
case YXDOMAIN:
rclass = C_ANY;
rtype = T_ANY;
rrecp->r_size = 0;
break;
case NXDOMAIN:
rclass = C_NONE;
rtype = T_ANY;
rrecp->r_size = 0;
break;
case NXRRSET:
rclass = C_NONE;
rrecp->r_size = 0;
break;
case YXRRSET:
if (rrecp->r_size == 0)
rclass = C_ANY;
break;
default:
fprintf(stderr,
"res_mkupdate: incorrect opcode: %d\n",
rrecp->r_opcode);
fflush(stderr);
return (-1);
}
} else if (section == S_UPDATE) {
switch (rrecp->r_opcode) {
case DELETE:
rclass = rrecp->r_size == 0 ? C_ANY : C_NONE;
break;
case ADD:
break;
default:
fprintf(stderr,
"res_mkupdate: incorrect opcode: %d\n",
rrecp->r_opcode);
fflush(stderr);
return (-1);
}
}

/*
* XXX appending default domain to owner name is omitted,
* fqdn must be provided
*/
if ((n = dn_comp(rrecp->r_dname, cp, buflen, dnptrs,
lastdnptr)) < 0)
return (-1);
cp += n;
ShrinkBuffer(n + 2*INT16SZ);
PUTSHORT(rtype, cp);
PUTSHORT(rclass, cp);
if (section == S_ZONE) {
if (numrrs != 1 || rrecp->r_type != T_SOA)
return (-3);
continue;
}
ShrinkBuffer(INT32SZ + INT16SZ);
PUTLONG(rttl, cp);
sp2 = cp; /*%< save pointer to length byte */
cp += INT16SZ;
if (rrecp->r_size == 0) {
if (section == S_UPDATE && rclass != C_ANY)
return (-1);
else {
PUTSHORT(0, sp2);
continue;
}
}
startp = rrecp->r_data;
endp = startp + rrecp->r_size - 1;
/* XXX this should be done centrally. */
switch (rrecp->r_type) {
case T_A:
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
if (!inet_aton(buf2, &ina))
return (-1);
n1 = ntohl(ina.s_addr);
ShrinkBuffer(INT32SZ);
PUTLONG(n1, cp);
break;
case T_CNAME:
case T_MB:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
case ns_t_dname:
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
break;
case T_MINFO:
case T_SOA:
case T_RP:
for (i = 0; i < 2; i++) {
if (!getword_str(buf2, sizeof buf2, &startp,
endp))
return (-1);
n = dn_comp(buf2, cp, buflen,
dnptrs, lastdnptr);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
}
if (rrecp->r_type == T_SOA) {
ShrinkBuffer(5 * INT32SZ);
while (isspace(*startp) || !*startp)
startp++;
if (*startp == '(') {
multiline = 1;
startp++;
} else
multiline = 0;
/* serial, refresh, retry, expire, minimum */
for (i = 0; i < 5; i++) {
soanum = getnum_str(&startp, endp);
if (soanum < 0)
return (-1);
PUTLONG(soanum, cp);
}
if (multiline) {
while (isspace(*startp) || !*startp)
startp++;
if (*startp != ')')
return (-1);
}
}
break;
case T_MX:
case T_AFSDB:
case T_RT:
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
break;
case T_SRV:
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);

n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);

n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);

if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, NULL, NULL);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
break;
case T_PX:
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
PUTSHORT(n, cp);
ShrinkBuffer(INT16SZ);
for (i = 0; i < 2; i++) {
if (!getword_str(buf2, sizeof buf2, &startp,
endp))
return (-1);
n = dn_comp(buf2, cp, buflen, dnptrs,
lastdnptr);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
}
break;
case T_WKS: {
char bm[MAXPORT/8];
unsigned int maxbm = 0;

if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
if (!inet_aton(buf2, &ina))
return (-1);
n1 = ntohl(ina.s_addr);
ShrinkBuffer(INT32SZ);
PUTLONG(n1, cp);

if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
if ((i = res_protocolnumber(buf2)) < 0)
return (-1);
ShrinkBuffer(1);
*cp++ = i & 0xff;

for (i = 0; i < MAXPORT/8 ; i++)
bm[i] = 0;

while (getword_str(buf2, sizeof buf2, &startp, endp)) {
if ((n = res_servicenumber(buf2)) <= 0)
return (-1);

if (n < MAXPORT) {
bm[n/8] |= (0x80>>(n%8));
if ((unsigned)n > maxbm)
maxbm = n;
} else
return (-1);
}
maxbm = maxbm/8 + 1;
ShrinkBuffer(maxbm);
memcpy(cp, bm, maxbm);
cp += maxbm;
break;
}
case T_HINFO:
for (i = 0; i < 2; i++) {
if ((n = getstr_str(buf2, sizeof buf2,
&startp, endp)) < 0)
return (-1);
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
}
break;
case T_TXT:
for (;;) {
if ((n = getstr_str(buf2, sizeof buf2,
&startp, endp)) < 0) {
if (cp != (sp2 + INT16SZ))
break;
return (-1);
}
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
}
break;
case T_X25:
/* RFC1183 */
if ((n = getstr_str(buf2, sizeof buf2, &startp,
endp)) < 0)
return (-1);
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
break;
case T_ISDN:
/* RFC1183 */
if ((n = getstr_str(buf2, sizeof buf2, &startp,
endp)) < 0)
return (-1);
if ((n > 255) || (n == 0))
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
if ((n = getstr_str(buf2, sizeof buf2, &startp,
endp)) < 0)
n = 0;
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
break;
case T_NSAP:
if ((n = inet_nsap_addr((char *)startp, (u_char *)buf2, sizeof(buf2))) != 0) {
ShrinkBuffer(n);
memcpy(cp, buf2, n);
cp += n;
} else {
return (-1);
}
break;
case T_LOC:
if ((n = loc_aton((char *)startp, (u_char *)buf2)) != 0) {
ShrinkBuffer(n);
memcpy(cp, buf2, n);
cp += n;
} else
return (-1);
break;
case ns_t_sig:
{
int sig_type, success, dateerror;
u_int32_t exptime, timesigned;

/* type */
if ((n = getword_str(buf2, sizeof buf2,
&startp, endp)) < 0)
return (-1);
sig_type = sym_ston(__p_type_syms, buf2, &success);
if (!success || sig_type == ns_t_any)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(sig_type, cp);
/* alg */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(1);
*cp++ = n;
/* labels */
n = getnum_str(&startp, endp);
if (n <= 0 || n > 255)
return (-1);
ShrinkBuffer(1);
*cp++ = n;
/* ottl & expire */
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
exptime = ns_datetosecs(buf2, &dateerror);
if (!dateerror) {
ShrinkBuffer(INT32SZ);
PUTLONG(rttl, cp);
}
else {
char *ulendp;
u_int32_t ottl;

errno = 0;
ottl = strtoul(buf2, &ulendp, 10);
if (errno != 0 ||
(ulendp != NULL && *ulendp != '\0'))
return (-1);
ShrinkBuffer(INT32SZ);
PUTLONG(ottl, cp);
if (!getword_str(buf2, sizeof buf2, &startp,
endp))
return (-1);
exptime = ns_datetosecs(buf2, &dateerror);
if (dateerror)
return (-1);
}
/* expire */
ShrinkBuffer(INT32SZ);
PUTLONG(exptime, cp);
/* timesigned */
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
timesigned = ns_datetosecs(buf2, &dateerror);
if (!dateerror) {
ShrinkBuffer(INT32SZ);
PUTLONG(timesigned, cp);
}
else
return (-1);
/* footprint */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* signer name */
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
/* sig */
if ((n = getword_str(buf2, sizeof buf2,
&startp, endp)) < 0)
return (-1);
siglen = b64_pton(buf2, buf3, sizeof(buf3));
if (siglen < 0)
return (-1);
ShrinkBuffer(siglen);
memcpy(cp, buf3, siglen);
cp += siglen;
break;
}
case ns_t_key:
/* flags */
n = gethexnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* proto */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(1);
*cp++ = n;
/* alg */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(1);
*cp++ = n;
/* key */
if ((n = getword_str(buf2, sizeof buf2,
&startp, endp)) < 0)
return (-1);
keylen = b64_pton(buf2, buf3, sizeof(buf3));
if (keylen < 0)
return (-1);
ShrinkBuffer(keylen);
memcpy(cp, buf3, keylen);
cp += keylen;
break;
case ns_t_nxt:
{
int success, nxt_type;
u_char data[32];
int maxtype;

/* next name */
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, NULL, NULL);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
maxtype = 0;
memset(data, 0, sizeof data);
for (;;) {
if (!getword_str(buf2, sizeof buf2, &startp,
endp))
break;
nxt_type = sym_ston(__p_type_syms, buf2,
&success);
if (!success || !ns_t_rr_p(nxt_type))
return (-1);
NS_NXT_BIT_SET(nxt_type, data);
if (nxt_type > maxtype)
maxtype = nxt_type;
}
n = maxtype/NS_NXT_BITS+1;
ShrinkBuffer(n);
memcpy(cp, data, n);
cp += n;
break;
}
case ns_t_cert:
/* type */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* key tag */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* alg */
n = getnum_str(&startp, endp);
if (n < 0)
return (-1);
ShrinkBuffer(1);
*cp++ = n;
/* cert */
if ((n = getword_str(buf2, sizeof buf2,
&startp, endp)) < 0)
return (-1);
certlen = b64_pton(buf2, buf3, sizeof(buf3));
if (certlen < 0)
return (-1);
ShrinkBuffer(certlen);
memcpy(cp, buf3, certlen);
cp += certlen;
break;
case ns_t_aaaa:
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
if (inet_pton(AF_INET6, buf2, &in6a) <= 0)
return (-1);
ShrinkBuffer(NS_IN6ADDRSZ);
memcpy(cp, &in6a, NS_IN6ADDRSZ);
cp += NS_IN6ADDRSZ;
break;
case ns_t_naptr:
/* Order Preference Flags Service Replacement Regexp */
/* Order */
n = getnum_str(&startp, endp);
if (n < 0 || n > 65535)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* Preference */
n = getnum_str(&startp, endp);
if (n < 0 || n > 65535)
return (-1);
ShrinkBuffer(INT16SZ);
PUTSHORT(n, cp);
/* Flags */
if ((n = getstr_str(buf2, sizeof buf2,
&startp, endp)) < 0) {
return (-1);
}
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
/* Service Classes */
if ((n = getstr_str(buf2, sizeof buf2,
&startp, endp)) < 0) {
return (-1);
}
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
/* Pattern */
if ((n = getstr_str(buf2, sizeof buf2,
&startp, endp)) < 0) {
return (-1);
}
if (n > 255)
return (-1);
ShrinkBuffer(n+1);
*cp++ = n;
memcpy(cp, buf2, n);
cp += n;
/* Replacement */
if (!getword_str(buf2, sizeof buf2, &startp, endp))
return (-1);
n = dn_comp(buf2, cp, buflen, NULL, NULL);
if (n < 0)
return (-1);
cp += n;
ShrinkBuffer(n);
break;
default:
return (-1);
} /*switch*/
n = (u_int16_t)((cp - sp2) - INT16SZ);
PUTSHORT(n, sp2);
} /*for*/

hp->qdcount = htons(counts[0]);
hp->ancount = htons(counts[1]);
hp->nscount = htons(counts[2]);
hp->arcount = htons(counts[3]);
return (cp - buf);
}

/*%
* Get a whitespace delimited word from a string (not file)
* into buf. modify the start pointer to point after the
* word in the string.
*/
static int
getword_str(char *buf, int size, u_char **startpp, u_char *endp) {
char *cp;
int c;

for (cp = buf; *startpp <= endp; ) {
c = **startpp;
if (isspace(c) || c == '\0') {
if (cp != buf) /*%< trailing whitespace */
break;
else { /*%< leading whitespace */
(*startpp)++;
continue;
}
}
(*startpp)++;
if (cp >= buf+size-1)
break;
*cp++ = (u_char)c;
}
*cp = '\0';
return (cp != buf);
}

/*%
* get a white spae delimited string from memory. Process quoted strings
* and \\DDD escapes. Return length or -1 on error. Returned string may
* contain nulls.
*/
static char digits[] = "0123456789";
static int
getstr_str(char *buf, int size, u_char **startpp, u_char *endp) {
char *cp;
int c, c1 = 0;
int inquote = 0;
int seen_quote = 0;
int escape = 0;
int dig = 0;

for (cp = buf; *startpp <= endp; ) {
if ((c = **startpp) == '\0')
break;
/* leading white space */
if ((cp == buf) && !seen_quote && isspace(c)) {
(*startpp)++;
continue;
}

switch (c) {
case '\\':
if (!escape) {
escape = 1;
dig = 0;
c1 = 0;
(*startpp)++;
continue;
}
goto do_escape;
case '"':
if (!escape) {
inquote = !inquote;
seen_quote = 1;
(*startpp)++;
continue;
}
/* fall through */
default:
do_escape:
if (escape) {
switch (c) {
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
c1 = c1 * 10 +
(strchr(digits, c) - digits);

if (++dig == 3) {
c = c1 &0xff;
break;
}
(*startpp)++;
continue;
}
escape = 0;
} else if (!inquote && isspace(c))
goto done;
if (cp >= buf+size-1)
goto done;
*cp++ = (u_char)c;
(*startpp)++;
}
}
done:
*cp = '\0';
return ((cp == buf)? (seen_quote? 0: -1): (cp - buf));
}

/*%
* Get a whitespace delimited base 16 number from a string (not file) into buf
* update the start pointer to point after the number in the string.
*/
static int
gethexnum_str(u_char **startpp, u_char *endp) {
int c, n;
int seendigit = 0;
int m = 0;

if (*startpp + 2 >= endp || strncasecmp((char *)*startpp, "0x", 2) != 0)
return getnum_str(startpp, endp);
(*startpp)+=2;
for (n = 0; *startpp <= endp; ) {
c = **startpp;
if (isspace(c) || c == '\0') {
if (seendigit) /*%< trailing whitespace */
break;
else { /*%< leading whitespace */
(*startpp)++;
continue;
}
}
if (c == ';') {
while ((*startpp <= endp) &&
((c = **startpp) != '\n'))
(*startpp)++;
if (seendigit)
break;
continue;
}
if (!isxdigit(c)) {
if (c == ')' && seendigit) {
(*startpp)--;
break;
}
return (-1);
}
(*startpp)++;
if (isdigit(c))
n = n * 16 + (c - '0');
else
n = n * 16 + (tolower(c) - 'a' + 10);
seendigit = 1;
}
return (n + m);
}

/*%
* Get a whitespace delimited base 10 number from a string (not file) into buf
* update the start pointer to point after the number in the string.
*/
static int
getnum_str(u_char **startpp, u_char *endp) {
int c, n;
int seendigit = 0;
int m = 0;

for (n = 0; *startpp <= endp; ) {
c = **startpp;
if (isspace(c) || c == '\0') {
if (seendigit) /*%< trailing whitespace */
break;
else { /*%< leading whitespace */
(*startpp)++;
continue;
}
}
if (c == ';') {
while ((*startpp <= endp) &&
((c = **startpp) != '\n'))
(*startpp)++;
if (seendigit)
break;
continue;
}
if (!isdigit(c)) {
if (c == ')' && seendigit) {
(*startpp)--;
break;
}
return (-1);
}
(*startpp)++;
n = n * 10 + (c - '0');
seendigit = 1;
}
return (n + m);
}

/*%
* Allocate a resource record buffer & save rr info.
*/
ns_updrec *
res_mkupdrec(int section, const char *dname,
u_int class, u_int type, u_long ttl) {
ns_updrec *rrecp = (ns_updrec *)calloc(1, sizeof(ns_updrec));

if (!rrecp || !(rrecp->r_dname = strdup(dname))) {
if (rrecp)
free((char *)rrecp);
return (NULL);
}
INIT_LINK(rrecp, r_link);
INIT_LINK(rrecp, r_glink);
rrecp->r_class = (ns_class)class;
rrecp->r_type = (ns_type)type;
rrecp->r_ttl = ttl;
rrecp->r_section = (ns_sect)section;
return (rrecp);
}

/*%
* Free a resource record buffer created by res_mkupdrec.
*/
void
res_freeupdrec(ns_updrec *rrecp) {
/* Note: freeing r_dp is the caller's responsibility. */
if (rrecp->r_dname != NULL)
free(rrecp->r_dname);
free(rrecp);
}

struct valuelist {
struct valuelist * next;
struct valuelist * prev;
char * name;
char * proto;
int port;
};
static struct valuelist *servicelist, *protolist;

static void
res_buildservicelist() {
struct servent *sp;
struct valuelist *slp;

#ifdef MAYBE_HESIOD
setservent(0);
#else
setservent(1);
#endif
while ((sp = getservent()) != NULL) {
slp = (struct valuelist *)malloc(sizeof(struct valuelist));
if (!slp)
break;
slp->name = strdup(sp->s_name);
slp->proto = strdup(sp->s_proto);
if ((slp->name == NULL) || (slp->proto == NULL)) {
if (slp->name) free(slp->name);
if (slp->proto) free(slp->proto);
free(slp);
break;
}
slp->port = ntohs((u_int16_t)sp->s_port); /*%< host byt order */
slp->next = servicelist;
slp->prev = NULL;
if (servicelist)
servicelist->prev = slp;
servicelist = slp;
}
endservent();
}

void
res_destroyservicelist() {
struct valuelist *slp, *slp_next;

for (slp = servicelist; slp != NULL; slp = slp_next) {
slp_next = slp->next;
free(slp->name);
free(slp->proto);
free(slp);
}
servicelist = (struct valuelist *)0;
}

void
res_buildprotolist(void) {
struct protoent *pp;
struct valuelist *slp;

#ifdef MAYBE_HESIOD
setprotoent(0);
#else
setprotoent(1);
#endif
while ((pp = getprotoent()) != NULL) {
slp = (struct valuelist *)malloc(sizeof(struct valuelist));
if (!slp)
break;
slp->name = strdup(pp->p_name);
if (slp->name == NULL) {
free(slp);
break;
}
slp->port = pp->p_proto; /*%< host byte order */
slp->next = protolist;
slp->prev = NULL;
if (protolist)
protolist->prev = slp;
protolist = slp;
}
endprotoent();
}

void
res_destroyprotolist(void) {
struct valuelist *plp, *plp_next;

for (plp = protolist; plp != NULL; plp = plp_next) {
plp_next = plp->next;
free(plp->name);
free(plp);
}
protolist = (struct valuelist *)0;
}

static int
findservice(const char *s, struct valuelist **list) {
struct valuelist *lp = *list;
int n;

for (; lp != NULL; lp = lp->next)
if (strcasecmp(lp->name, s) == 0) {
if (lp != *list) {
lp->prev->next = lp->next;
if (lp->next)
lp->next->prev = lp->prev;
(*list)->prev = lp;
lp->next = *list;
*list = lp;
}
return (lp->port); /*%< host byte order */
}
if (sscanf(s, "%d", &n) != 1 || n <= 0)
n = -1;
return (n);
}

/*%
* Convert service name or (ascii) number to int.
*/
int
res_servicenumber(const char *p) {
if (servicelist == (struct valuelist *)0)
res_buildservicelist();
return (findservice(p, &servicelist));
}

/*%
* Convert protocol name or (ascii) number to int.
*/
int
res_protocolnumber(const char *p) {
if (protolist == (struct valuelist *)0)
res_buildprotolist();
return (findservice(p, &protolist));
}

static struct servent *
cgetservbyport(u_int16_t port, const char *proto) { /*%< Host byte order. */
struct valuelist **list = &servicelist;
struct valuelist *lp = *list;
static struct servent serv;

port = ntohs(port);
for (; lp != NULL; lp = lp->next) {
if (port != (u_int16_t)lp->port) /*%< Host byte order. */
continue;
if (strcasecmp(lp->proto, proto) == 0) {
if (lp != *list) {
lp->prev->next = lp->next;
if (lp->next)
lp->next->prev = lp->prev;
(*list)->prev = lp;
lp->next = *list;
*list = lp;
}
serv.s_name = lp->name;
serv.s_port = htons((u_int16_t)lp->port);
serv.s_proto = lp->proto;
return (&serv);
}
}
return (0);
}

static struct protoent *
cgetprotobynumber(int proto) { /*%< Host byte order. */
struct valuelist **list = &protolist;
struct valuelist *lp = *list;
static struct protoent prot;

for (; lp != NULL; lp = lp->next)
if (lp->port == proto) { /*%< Host byte order. */
if (lp != *list) {
lp->prev->next = lp->next;
if (lp->next)
lp->next->prev = lp->prev;
(*list)->prev = lp;
lp->next = *list;
*list = lp;
}
prot.p_name = lp->name;
prot.p_proto = lp->port; /*%< Host byte order. */
return (&prot);
}
return (0);
}

const char *
res_protocolname(int num) {
static char number[8];
struct protoent *pp;

if (protolist == (struct valuelist *)0)
res_buildprotolist();
pp = cgetprotobynumber(num);
if (pp == 0) {
(void) sprintf(number, "%d", num);
return (number);
}
return (pp->p_name);
}

const char *
res_servicename(u_int16_t port, const char *proto) { /*%< Host byte order. */
static char number[8];
struct servent *ss;

if (servicelist == (struct valuelist *)0)
res_buildservicelist();
ss = cgetservbyport(htons(port), proto);
if (ss == 0) {
(void) sprintf(number, "%d", port);
return (number);
}
return (ss->s_name);
}