| Current Path : /usr/src/crypto/heimdal/lib/roken/ |
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| Current File : //usr/src/crypto/heimdal/lib/roken/resolve.c |
/*
* Copyright (c) 1995 - 2006 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* 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 Institute 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 INSTITUTE 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 INSTITUTE 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.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "roken.h"
#ifdef HAVE_ARPA_NAMESER_H
#include <arpa/nameser.h>
#endif
#ifdef HAVE_RESOLV_H
#include <resolv.h>
#endif
#include "resolve.h"
#include <assert.h>
RCSID("$Id: resolve.c 19869 2007-01-12 16:03:14Z lha $");
#ifdef _AIX /* AIX have broken res_nsearch() in 5.1 (5.0 also ?) */
#undef HAVE_RES_NSEARCH
#endif
#define DECL(X) {#X, rk_ns_t_##X}
static struct stot{
const char *name;
int type;
}stot[] = {
DECL(a),
DECL(aaaa),
DECL(ns),
DECL(cname),
DECL(soa),
DECL(ptr),
DECL(mx),
DECL(txt),
DECL(afsdb),
DECL(sig),
DECL(key),
DECL(srv),
DECL(naptr),
DECL(sshfp),
DECL(ds),
{NULL, 0}
};
int _resolve_debug = 0;
int ROKEN_LIB_FUNCTION
dns_string_to_type(const char *name)
{
struct stot *p = stot;
for(p = stot; p->name; p++)
if(strcasecmp(name, p->name) == 0)
return p->type;
return -1;
}
const char * ROKEN_LIB_FUNCTION
dns_type_to_string(int type)
{
struct stot *p = stot;
for(p = stot; p->name; p++)
if(type == p->type)
return p->name;
return NULL;
}
#if (defined(HAVE_RES_SEARCH) || defined(HAVE_RES_NSEARCH)) && defined(HAVE_DN_EXPAND)
static void
dns_free_rr(struct resource_record *rr)
{
if(rr->domain)
free(rr->domain);
if(rr->u.data)
free(rr->u.data);
free(rr);
}
void ROKEN_LIB_FUNCTION
dns_free_data(struct dns_reply *r)
{
struct resource_record *rr;
if(r->q.domain)
free(r->q.domain);
for(rr = r->head; rr;){
struct resource_record *tmp = rr;
rr = rr->next;
dns_free_rr(tmp);
}
free (r);
}
static int
parse_record(const unsigned char *data, const unsigned char *end_data,
const unsigned char **pp, struct resource_record **ret_rr)
{
struct resource_record *rr;
int type, class, ttl, size;
int status;
char host[MAXDNAME];
const unsigned char *p = *pp;
*ret_rr = NULL;
status = dn_expand(data, end_data, p, host, sizeof(host));
if(status < 0)
return -1;
if (p + status + 10 > end_data)
return -1;
p += status;
type = (p[0] << 8) | p[1];
p += 2;
class = (p[0] << 8) | p[1];
p += 2;
ttl = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
p += 4;
size = (p[0] << 8) | p[1];
p += 2;
if (p + size > end_data)
return -1;
rr = calloc(1, sizeof(*rr));
if(rr == NULL)
return -1;
rr->domain = strdup(host);
if(rr->domain == NULL) {
dns_free_rr(rr);
return -1;
}
rr->type = type;
rr->class = class;
rr->ttl = ttl;
rr->size = size;
switch(type){
case rk_ns_t_ns:
case rk_ns_t_cname:
case rk_ns_t_ptr:
status = dn_expand(data, end_data, p, host, sizeof(host));
if(status < 0) {
dns_free_rr(rr);
return -1;
}
rr->u.txt = strdup(host);
if(rr->u.txt == NULL) {
dns_free_rr(rr);
return -1;
}
break;
case rk_ns_t_mx:
case rk_ns_t_afsdb:{
size_t hostlen;
status = dn_expand(data, end_data, p + 2, host, sizeof(host));
if(status < 0){
dns_free_rr(rr);
return -1;
}
if (status + 2 > size) {
dns_free_rr(rr);
return -1;
}
hostlen = strlen(host);
rr->u.mx = (struct mx_record*)malloc(sizeof(struct mx_record) +
hostlen);
if(rr->u.mx == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.mx->preference = (p[0] << 8) | p[1];
strlcpy(rr->u.mx->domain, host, hostlen + 1);
break;
}
case rk_ns_t_srv:{
size_t hostlen;
status = dn_expand(data, end_data, p + 6, host, sizeof(host));
if(status < 0){
dns_free_rr(rr);
return -1;
}
if (status + 6 > size) {
dns_free_rr(rr);
return -1;
}
hostlen = strlen(host);
rr->u.srv =
(struct srv_record*)malloc(sizeof(struct srv_record) +
hostlen);
if(rr->u.srv == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.srv->priority = (p[0] << 8) | p[1];
rr->u.srv->weight = (p[2] << 8) | p[3];
rr->u.srv->port = (p[4] << 8) | p[5];
strlcpy(rr->u.srv->target, host, hostlen + 1);
break;
}
case rk_ns_t_txt:{
if(size == 0 || size < *p + 1) {
dns_free_rr(rr);
return -1;
}
rr->u.txt = (char*)malloc(*p + 1);
if(rr->u.txt == NULL) {
dns_free_rr(rr);
return -1;
}
strncpy(rr->u.txt, (const char*)(p + 1), *p);
rr->u.txt[*p] = '\0';
break;
}
case rk_ns_t_key : {
size_t key_len;
if (size < 4) {
dns_free_rr(rr);
return -1;
}
key_len = size - 4;
rr->u.key = malloc (sizeof(*rr->u.key) + key_len - 1);
if (rr->u.key == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.key->flags = (p[0] << 8) | p[1];
rr->u.key->protocol = p[2];
rr->u.key->algorithm = p[3];
rr->u.key->key_len = key_len;
memcpy (rr->u.key->key_data, p + 4, key_len);
break;
}
case rk_ns_t_sig : {
size_t sig_len, hostlen;
if(size <= 18) {
dns_free_rr(rr);
return -1;
}
status = dn_expand (data, end_data, p + 18, host, sizeof(host));
if (status < 0) {
dns_free_rr(rr);
return -1;
}
if (status + 18 > size) {
dns_free_rr(rr);
return -1;
}
/* the signer name is placed after the sig_data, to make it
easy to free this structure; the size calculation below
includes the zero-termination if the structure itself.
don't you just love C?
*/
sig_len = size - 18 - status;
hostlen = strlen(host);
rr->u.sig = malloc(sizeof(*rr->u.sig)
+ hostlen + sig_len);
if (rr->u.sig == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.sig->type = (p[0] << 8) | p[1];
rr->u.sig->algorithm = p[2];
rr->u.sig->labels = p[3];
rr->u.sig->orig_ttl = (p[4] << 24) | (p[5] << 16)
| (p[6] << 8) | p[7];
rr->u.sig->sig_expiration = (p[8] << 24) | (p[9] << 16)
| (p[10] << 8) | p[11];
rr->u.sig->sig_inception = (p[12] << 24) | (p[13] << 16)
| (p[14] << 8) | p[15];
rr->u.sig->key_tag = (p[16] << 8) | p[17];
rr->u.sig->sig_len = sig_len;
memcpy (rr->u.sig->sig_data, p + 18 + status, sig_len);
rr->u.sig->signer = &rr->u.sig->sig_data[sig_len];
strlcpy(rr->u.sig->signer, host, hostlen + 1);
break;
}
case rk_ns_t_cert : {
size_t cert_len;
if (size < 5) {
dns_free_rr(rr);
return -1;
}
cert_len = size - 5;
rr->u.cert = malloc (sizeof(*rr->u.cert) + cert_len - 1);
if (rr->u.cert == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.cert->type = (p[0] << 8) | p[1];
rr->u.cert->tag = (p[2] << 8) | p[3];
rr->u.cert->algorithm = p[4];
rr->u.cert->cert_len = cert_len;
memcpy (rr->u.cert->cert_data, p + 5, cert_len);
break;
}
case rk_ns_t_sshfp : {
size_t sshfp_len;
if (size < 2) {
dns_free_rr(rr);
return -1;
}
sshfp_len = size - 2;
rr->u.sshfp = malloc (sizeof(*rr->u.sshfp) + sshfp_len - 1);
if (rr->u.sshfp == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.sshfp->algorithm = p[0];
rr->u.sshfp->type = p[1];
rr->u.sshfp->sshfp_len = sshfp_len;
memcpy (rr->u.sshfp->sshfp_data, p + 2, sshfp_len);
break;
}
case rk_ns_t_ds: {
size_t digest_len;
if (size < 4) {
dns_free_rr(rr);
return -1;
}
digest_len = size - 4;
rr->u.ds = malloc (sizeof(*rr->u.ds) + digest_len - 1);
if (rr->u.ds == NULL) {
dns_free_rr(rr);
return -1;
}
rr->u.ds->key_tag = (p[0] << 8) | p[1];
rr->u.ds->algorithm = p[2];
rr->u.ds->digest_type = p[3];
rr->u.ds->digest_len = digest_len;
memcpy (rr->u.ds->digest_data, p + 4, digest_len);
break;
}
default:
rr->u.data = (unsigned char*)malloc(size);
if(size != 0 && rr->u.data == NULL) {
dns_free_rr(rr);
return -1;
}
if (size)
memcpy(rr->u.data, p, size);
}
*pp = p + size;
*ret_rr = rr;
return 0;
}
#ifndef TEST_RESOLVE
static
#endif
struct dns_reply*
parse_reply(const unsigned char *data, size_t len)
{
const unsigned char *p;
int status;
int i;
char host[MAXDNAME];
const unsigned char *end_data = data + len;
struct dns_reply *r;
struct resource_record **rr;
r = calloc(1, sizeof(*r));
if (r == NULL)
return NULL;
p = data;
r->h.id = (p[0] << 8) | p[1];
r->h.flags = 0;
if (p[2] & 0x01)
r->h.flags |= rk_DNS_HEADER_RESPONSE_FLAG;
r->h.opcode = (p[2] >> 1) & 0xf;
if (p[2] & 0x20)
r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
if (p[2] & 0x40)
r->h.flags |= rk_DNS_HEADER_TRUNCATED_MESSAGE;
if (p[2] & 0x80)
r->h.flags |= rk_DNS_HEADER_RECURSION_DESIRED;
if (p[3] & 0x01)
r->h.flags |= rk_DNS_HEADER_RECURSION_AVAILABLE;
if (p[3] & 0x04)
r->h.flags |= rk_DNS_HEADER_AUTHORITIVE_ANSWER;
if (p[3] & 0x08)
r->h.flags |= rk_DNS_HEADER_CHECKING_DISABLED;
r->h.response_code = (p[3] >> 4) & 0xf;
r->h.qdcount = (p[4] << 8) | p[5];
r->h.ancount = (p[6] << 8) | p[7];
r->h.nscount = (p[8] << 8) | p[9];
r->h.arcount = (p[10] << 8) | p[11];
p += 12;
if(r->h.qdcount != 1) {
free(r);
return NULL;
}
status = dn_expand(data, end_data, p, host, sizeof(host));
if(status < 0){
dns_free_data(r);
return NULL;
}
r->q.domain = strdup(host);
if(r->q.domain == NULL) {
dns_free_data(r);
return NULL;
}
if (p + status + 4 > end_data) {
dns_free_data(r);
return NULL;
}
p += status;
r->q.type = (p[0] << 8 | p[1]);
p += 2;
r->q.class = (p[0] << 8 | p[1]);
p += 2;
rr = &r->head;
for(i = 0; i < r->h.ancount; i++) {
if(parse_record(data, end_data, &p, rr) != 0) {
dns_free_data(r);
return NULL;
}
rr = &(*rr)->next;
}
for(i = 0; i < r->h.nscount; i++) {
if(parse_record(data, end_data, &p, rr) != 0) {
dns_free_data(r);
return NULL;
}
rr = &(*rr)->next;
}
for(i = 0; i < r->h.arcount; i++) {
if(parse_record(data, end_data, &p, rr) != 0) {
dns_free_data(r);
return NULL;
}
rr = &(*rr)->next;
}
*rr = NULL;
return r;
}
#ifdef HAVE_RES_NSEARCH
#ifdef HAVE_RES_NDESTROY
#define rk_res_free(x) res_ndestroy(x)
#else
#define rk_res_free(x) res_nclose(x)
#endif
#endif
static struct dns_reply *
dns_lookup_int(const char *domain, int rr_class, int rr_type)
{
struct dns_reply *r;
unsigned char *reply = NULL;
int size;
int len;
#ifdef HAVE_RES_NSEARCH
struct __res_state state;
memset(&state, 0, sizeof(state));
if(res_ninit(&state))
return NULL; /* is this the best we can do? */
#elif defined(HAVE__RES)
u_long old_options = 0;
#endif
size = 0;
len = 1000;
do {
if (reply) {
free(reply);
reply = NULL;
}
if (size <= len)
size = len;
if (_resolve_debug) {
#ifdef HAVE_RES_NSEARCH
state.options |= RES_DEBUG;
#elif defined(HAVE__RES)
old_options = _res.options;
_res.options |= RES_DEBUG;
#endif
fprintf(stderr, "dns_lookup(%s, %d, %s), buffer size %d\n", domain,
rr_class, dns_type_to_string(rr_type), size);
}
reply = malloc(size);
if (reply == NULL) {
#ifdef HAVE_RES_NSEARCH
rk_res_free(&state);
#endif
return NULL;
}
#ifdef HAVE_RES_NSEARCH
len = res_nsearch(&state, domain, rr_class, rr_type, reply, size);
#else
len = res_search(domain, rr_class, rr_type, reply, size);
#endif
if (_resolve_debug) {
#if defined(HAVE__RES) && !defined(HAVE_RES_NSEARCH)
_res.options = old_options;
#endif
fprintf(stderr, "dns_lookup(%s, %d, %s) --> %d\n",
domain, rr_class, dns_type_to_string(rr_type), len);
}
if (len < 0) {
#ifdef HAVE_RES_NSEARCH
rk_res_free(&state);
#endif
free(reply);
return NULL;
}
} while (size < len && len < rk_DNS_MAX_PACKET_SIZE);
#ifdef HAVE_RES_NSEARCH
rk_res_free(&state);
#endif
len = min(len, size);
r = parse_reply(reply, len);
free(reply);
return r;
}
struct dns_reply * ROKEN_LIB_FUNCTION
dns_lookup(const char *domain, const char *type_name)
{
int type;
type = dns_string_to_type(type_name);
if(type == -1) {
if(_resolve_debug)
fprintf(stderr, "dns_lookup: unknown resource type: `%s'\n",
type_name);
return NULL;
}
return dns_lookup_int(domain, C_IN, type);
}
static int
compare_srv(const void *a, const void *b)
{
const struct resource_record *const* aa = a, *const* bb = b;
if((*aa)->u.srv->priority == (*bb)->u.srv->priority)
return ((*aa)->u.srv->weight - (*bb)->u.srv->weight);
return ((*aa)->u.srv->priority - (*bb)->u.srv->priority);
}
#ifndef HAVE_RANDOM
#define random() rand()
#endif
/* try to rearrange the srv-records by the algorithm in RFC2782 */
void ROKEN_LIB_FUNCTION
dns_srv_order(struct dns_reply *r)
{
struct resource_record **srvs, **ss, **headp;
struct resource_record *rr;
int num_srv = 0;
#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
int state[256 / sizeof(int)];
char *oldstate;
#endif
for(rr = r->head; rr; rr = rr->next)
if(rr->type == rk_ns_t_srv)
num_srv++;
if(num_srv == 0)
return;
srvs = malloc(num_srv * sizeof(*srvs));
if(srvs == NULL)
return; /* XXX not much to do here */
/* unlink all srv-records from the linked list and put them in
a vector */
for(ss = srvs, headp = &r->head; *headp; )
if((*headp)->type == rk_ns_t_srv) {
*ss = *headp;
*headp = (*headp)->next;
(*ss)->next = NULL;
ss++;
} else
headp = &(*headp)->next;
/* sort them by priority and weight */
qsort(srvs, num_srv, sizeof(*srvs), compare_srv);
#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
oldstate = initstate(time(NULL), (char*)state, sizeof(state));
#endif
headp = &r->head;
for(ss = srvs; ss < srvs + num_srv; ) {
int sum, rnd, count;
struct resource_record **ee, **tt;
/* find the last record with the same priority and count the
sum of all weights */
for(sum = 0, tt = ss; tt < srvs + num_srv; tt++) {
assert(*tt != NULL);
if((*tt)->u.srv->priority != (*ss)->u.srv->priority)
break;
sum += (*tt)->u.srv->weight;
}
ee = tt;
/* ss is now the first record of this priority and ee is the
first of the next */
while(ss < ee) {
rnd = random() % (sum + 1);
for(count = 0, tt = ss; ; tt++) {
if(*tt == NULL)
continue;
count += (*tt)->u.srv->weight;
if(count >= rnd)
break;
}
assert(tt < ee);
/* insert the selected record at the tail (of the head) of
the list */
(*tt)->next = *headp;
*headp = *tt;
headp = &(*tt)->next;
sum -= (*tt)->u.srv->weight;
*tt = NULL;
while(ss < ee && *ss == NULL)
ss++;
}
}
#if defined(HAVE_INITSTATE) && defined(HAVE_SETSTATE)
setstate(oldstate);
#endif
free(srvs);
return;
}
#else /* NOT defined(HAVE_RES_SEARCH) && defined(HAVE_DN_EXPAND) */
struct dns_reply * ROKEN_LIB_FUNCTION
dns_lookup(const char *domain, const char *type_name)
{
return NULL;
}
void ROKEN_LIB_FUNCTION
dns_free_data(struct dns_reply *r)
{
}
void ROKEN_LIB_FUNCTION
dns_srv_order(struct dns_reply *r)
{
}
#endif