resolve.c

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/*
 * Copyright (c) 1995 - 2006 Kungliga Tekniska H鰃skolan
 * (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];