/* Like ares_expand_name but returns EBADRESP in case of invalid input. */
int ares__expand_name_for_response(const unsigned char *encoded,
const unsigned char *abuf, int alen,
char **s, long *enclen)
{
int status = ares_expand_name(encoded, abuf, alen, s, enclen);
if (status == ARES_EBADNAME)
status = ARES_EBADRESP;
return status;
}
void DNSTaskResolvCallback(void *arg, int status, int timeouts, unsigned char *abuf, int alen) {
struct DNSTask *dnstask = (struct DNSTask *) arg;
char *query;
int id, qr, opcode, aa, tc, rd, ra, rcode;
long len;
unsigned int qdcount, ancount, nscount, arcount, i;
const unsigned char *aptr;
debug("LobjId:%d, Hostname %s", dnstask->task->LObjId, dnstask->task->Record.HostName);
if (status != ARES_SUCCESS and status != ARES_ENODATA) {
return;
}
/* Parse the answer header. */
id = DNS_HEADER_QID(abuf);
qr = DNS_HEADER_QR(abuf);
opcode = DNS_HEADER_OPCODE(abuf);
aa = DNS_HEADER_AA(abuf);
tc = DNS_HEADER_TC(abuf);
rd = DNS_HEADER_RD(abuf);
ra = DNS_HEADER_RA(abuf);
rcode = DNS_HEADER_RCODE(abuf);
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
nscount = DNS_HEADER_NSCOUNT(abuf);
arcount = DNS_HEADER_ARCOUNT(abuf);
aptr = abuf + HFIXEDSZ;
ares_expand_name(aptr, abuf, alen, &query, &len);
for (i = 0; i < qdcount; i++) {
aptr = skip_question(aptr, abuf, alen);
if (aptr == NULL) return;
}
dnstask->task->code = STATE_ERROR;
switch (dnstask->role) {
case DNS_TASK:
for (i = 0; i < ancount; i++) {
debug("try %d %d ", dnstask->task->LObjId, ancount);
aptr = CheckPatternAfterParseAnswer(dnstask, aptr, abuf, alen);
if (aptr == NULL) break;
}
dnstask->task->callback(dnstask->task);
break;
}
}
static const unsigned char *skip_query(const unsigned char *aptr, const unsigned char *abuf, int alen) {
int status;
long len;
char *name;
dbg("skipping query section...\n");
status = ares_expand_name(aptr, abuf, alen, &name, &len);
aptr += len;
aptr += NS_QFIXEDSZ;
free(name);
return aptr;
}
static const unsigned char *skip_rr(const unsigned char *aptr, const unsigned char *abuf, int alen) {
int status, dlen;
long len;
char *name;
dbg("skipping rr section...\n");
status = ares_expand_name(aptr, abuf, alen, &name, &len);
aptr += len;
dlen = DNS_RR_LEN(aptr);
aptr += NS_RRFIXEDSZ;
aptr += dlen;
free(name);
return aptr;
}
int LLAres::expandName(const char *encoded, const char *abuf, size_t alen,
std::string &s, size_t &enclen)
{
char *t;
int ret;
long e;
ret = ares_expand_name((const unsigned char *) encoded,
(const unsigned char *) abuf, alen, &t, &e);
if (ret == ARES_SUCCESS)
{
s.assign(t);
enclen = e;
ares_free_string(t);
}
return ret;
}
static const unsigned char *display_question(const unsigned char *aptr,
const unsigned char *abuf, int alen,
dns_resp_t *response)
{
char *name;
int type, dnsclass, status;
long len;
/* Parse the question name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
aptr += len;
/* Make sure there's enough data after the name for the fixed part
* of the question.
*/
if (aptr + QFIXEDSZ > abuf + alen) {
xfree(name);
return NULL;
}
/* Parse the question type and class. */
type = DNS_QUESTION_TYPE(aptr);
dnsclass = DNS_QUESTION_CLASS(aptr);
aptr += QFIXEDSZ;
/*
* Display the question, in a format sort of similar to how we will
* display RRs.
*/
sprintf(msg, "\t%-15s.\t", name);
addtobuffer(response->msgbuf, msg);
if (dnsclass != C_IN) {
sprintf(msg, "\t%s", class_name(dnsclass));
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\t%s\n", type_name(type));
addtobuffer(response->msgbuf, msg);
xfree(name);
return aptr;
}
int ares_parse_ns_reply( const unsigned char* abuf, int alen,
struct hostent** host )
{
unsigned int qdcount, ancount;
int status, i, rr_type, rr_class, rr_len;
int nameservers_num;
long len;
const unsigned char *aptr;
char* hostname, *rr_name, *rr_data, **nameservers;
struct hostent *hostent;
/* Set *host to NULL for all failure cases. */
*host = NULL;
/* Give up if abuf doesn't have room for a header. */
if ( alen < HFIXEDSZ )
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT( abuf );
ancount = DNS_HEADER_ANCOUNT( abuf );
if ( qdcount != 1 )
return ARES_EBADRESP;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name( aptr, abuf, alen, &hostname, &len );
if ( status != ARES_SUCCESS )
return status;
if ( aptr + len + QFIXEDSZ > abuf + alen )
{
free( hostname );
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Allocate nameservers array; ancount gives an upper bound */
nameservers = malloc( ( ancount + 1 ) * sizeof( char * ) );
if ( !nameservers )
{
free( hostname );
return ARES_ENOMEM;
}
nameservers_num = 0;
/* Examine each answer resource record (RR) in turn. */
for ( i = 0; i < ( int ) ancount; i++ )
{
/* Decode the RR up to the data field. */
status = ares_expand_name( aptr, abuf, alen, &rr_name, &len );
if ( status != ARES_SUCCESS )
break;
aptr += len;
if ( aptr + RRFIXEDSZ > abuf + alen )
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE( aptr );
rr_class = DNS_RR_CLASS( aptr );
rr_len = DNS_RR_LEN( aptr );
aptr += RRFIXEDSZ;
if ( rr_class == C_IN && rr_type == T_NS )
{
/* Decode the RR data and add it to the nameservers list */
status = ares_expand_name( aptr, abuf, alen, &rr_data, &len );
if ( status != ARES_SUCCESS )
{
break;
}
nameservers[nameservers_num] = malloc(strlen(rr_data)+1);
if (nameservers[nameservers_num]==NULL)
{
free(rr_name);
free(rr_data);
status=ARES_ENOMEM;
break;
}
strcpy(nameservers[nameservers_num],rr_data);
free(rr_data);
nameservers_num++;
}
free( rr_name );
aptr += rr_len;
if ( aptr > abuf + alen )
{
status = ARES_EBADRESP;
break;
}
}
if ( status == ARES_SUCCESS && nameservers_num == 0 )
{
status = ARES_ENODATA;
}
if ( status == ARES_SUCCESS )
{
/* We got our answer. Allocate memory to build the host entry. */
nameservers[nameservers_num] = NULL;
hostent = malloc( sizeof( struct hostent ) );
if ( hostent )
{
hostent->h_addr_list = malloc( 1 * sizeof( char * ) );
if ( hostent->h_addr_list )
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
hostent->h_aliases = nameservers;
hostent->h_addrtype = AF_INET;
hostent->h_length = sizeof( struct in_addr );
hostent->h_addr_list[0] = NULL;
*host = hostent;
return ARES_SUCCESS;
}
free( hostent );
}
status = ARES_ENOMEM;
}
for ( i = 0; i < nameservers_num; i++ )
free( nameservers[i] );
free( nameservers );
free( hostname );
return status;
}
static const unsigned char *display_rr(const unsigned char *aptr,
const unsigned char *abuf, int alen)
{
const unsigned char *p;
int type, dnsclass, ttl, dlen, status;
long len;
char addr[46];
union {
unsigned char * as_uchar;
char * as_char;
} name;
/* Parse the RR name. */
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
aptr += len;
/* Make sure there is enough data after the RR name for the fixed
* part of the RR.
*/
if (aptr + RRFIXEDSZ > abuf + alen)
{
ares_free_string(name.as_char);
return NULL;
}
/* Parse the fixed part of the RR, and advance to the RR data
* field. */
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen)
{
ares_free_string(name.as_char);
return NULL;
}
/* Display the RR name, class, and type. */
printf("\t%-15s.\t%d", name.as_char, ttl);
if (dnsclass != C_IN)
printf("\t%s", class_name(dnsclass));
printf("\t%s", type_name(type));
ares_free_string(name.as_char);
/* Display the RR data. Don't touch aptr. */
switch (type)
{
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
/* For these types, the RR data is just a domain name. */
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
p += len;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_MX:
/* The RR data is two bytes giving a preference ordering, and
* then a domain name.
*/
if (dlen < 2)
return NULL;
printf("\t%d", DNS__16BIT(aptr));
status = ares_expand_name(aptr + 2, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_SOA:
/* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s.\n", name.as_char);
ares_free_string(name.as_char);
p += len;
if (p + 20 > aptr + dlen)
return NULL;
printf("\t\t\t\t\t\t( %lu %lu %lu %lu %lu )",
(unsigned long)DNS__32BIT(p), (unsigned long)DNS__32BIT(p+4),
(unsigned long)DNS__32BIT(p+8), (unsigned long)DNS__32BIT(p+12),
(unsigned long)DNS__32BIT(p+16));
break;
case T_TXT:
/* The RR data is one or more length-counted character
* strings. */
p = aptr;
while (p < aptr + dlen)
{
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
p += len;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
if (dlen != 4)
return NULL;
printf("\t%s", ares_inet_ntop(AF_INET,aptr,addr,sizeof(addr)));
break;
case T_AAAA:
/* The RR data is a 16-byte IPv6 address. */
if (dlen != 16)
return NULL;
printf("\t%s", ares_inet_ntop(AF_INET6,aptr,addr,sizeof(addr)));
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
printf("\t%d", DNS__16BIT(aptr));
printf(" %d", DNS__16BIT(aptr + 2));
printf(" %d", DNS__16BIT(aptr + 4));
status = ares_expand_name(aptr + 6, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_NAPTR:
printf("\t%d", DNS__16BIT(aptr)); /* order */
printf(" %d\n", DNS__16BIT(aptr + 2)); /* preference */
p = aptr + 4;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s", name.as_char);
ares_free_string(name.as_char);
break;
default:
printf("\t[Unknown RR; cannot parse]");
break;
}
printf("\n");
return aptr + dlen;
}
static const unsigned char *display_rr(const unsigned char *aptr,
const unsigned char *abuf, int alen,
dns_resp_t *response)
{
const unsigned char *p;
char *name;
int type, dnsclass, ttl, dlen, status;
long len;
struct in_addr addr;
/* Parse the RR name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
aptr += len;
/* Make sure there is enough data after the RR name for the fixed
* part of the RR.
*/
if (aptr + RRFIXEDSZ > abuf + alen) {
xfree(name);
return NULL;
}
/* Parse the fixed part of the RR, and advance to the RR data field. */
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
xfree(name);
return NULL;
}
/* Display the RR name, class, and type. */
sprintf(msg, "\t%-15s.\t%d", name, ttl);
addtobuffer(response->msgbuf, msg);
if (dnsclass != C_IN) {
sprintf(msg, "\t%s", class_name(dnsclass));
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\t%s", type_name(type));
addtobuffer(response->msgbuf, msg);
xfree(name);
/* Display the RR data. Don't touch aptr. */
switch (type) {
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
/* For these types, the RR data is just a domain name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int) len, p + 1);
addtobuffer(response->msgbuf, msg);
p += len + 1;
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int) len, p + 1);
addtobuffer(response->msgbuf, msg);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_MX:
/* The RR data is two bytes giving a preference ordering, and then a domain name. */
if (dlen < 2) return NULL;
sprintf(msg, "\t%d", (aptr[0] << 8) | aptr[1]);
addtobuffer(response->msgbuf, msg);
status = ares_expand_name(aptr + 2, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_SOA:
/*
* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.\n", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t\t\t\t\t\t%s.\n", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
if (p + 20 > aptr + dlen) return NULL;
sprintf(msg, "\t\t\t\t\t\t( %d %d %d %d %d )",
(p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3],
(p[4] << 24) | (p[5] << 16) | (p[6] << 8) | p[7],
(p[8] << 24) | (p[9] << 16) | (p[10] << 8) | p[11],
(p[12] << 24) | (p[13] << 16) | (p[14] << 8) | p[15],
(p[16] << 24) | (p[17] << 16) | (p[18] << 8) | p[19]);
addtobuffer(response->msgbuf, msg);
break;
case T_TXT:
/* The RR data is one or more length-counted character strings. */
p = aptr;
while (p < aptr + dlen) {
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int)len, p + 1);
addtobuffer(response->msgbuf, msg);
p += len + 1;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
if (dlen != 4) return NULL;
memcpy(&addr, aptr, sizeof(struct in_addr));
sprintf(msg, "\t%s", inet_ntoa(addr));
addtobuffer(response->msgbuf, msg);
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/*
* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
sprintf(msg, "\t%d", DNS__16BIT(aptr));
addtobuffer(response->msgbuf, msg);
sprintf(msg, " %d", DNS__16BIT(aptr + 2));
addtobuffer(response->msgbuf, msg);
sprintf(msg, " %d", DNS__16BIT(aptr + 4));
addtobuffer(response->msgbuf, msg);
status = ares_expand_name(aptr + 6, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
default:
sprintf(msg, "\t[Unknown RR; cannot parse]");
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\n");
addtobuffer(response->msgbuf, msg);
return aptr + dlen;
}
int
ares_parse_txt_reply (const unsigned char *abuf, int alen,
struct ares_txt_reply **txt_out)
{
size_t substr_len;
unsigned int qdcount, ancount, i;
const unsigned char *aptr;
const unsigned char *strptr;
int status, rr_type, rr_class, rr_len;
long len;
char *hostname = NULL, *rr_name = NULL;
struct ares_txt_reply *txt_head = NULL;
struct ares_txt_reply *txt_last = NULL;
struct ares_txt_reply *txt_curr;
/* Set *txt_out to NULL for all failure cases. */
*txt_out = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT (abuf);
ancount = DNS_HEADER_ANCOUNT (abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_ENODATA;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free (hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
{
break;
}
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE (aptr);
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
/* Check if we are really looking at a TXT record */
if (rr_class == C_IN && rr_type == T_TXT)
{
/*
* There may be multiple substrings in a single TXT record. Each
* substring may be up to 255 characters in length, with a
* "length byte" indicating the size of the substring payload.
* RDATA contains both the length-bytes and payloads of all
* substrings contained therein.
*/
strptr = aptr;
while (strptr < (aptr + rr_len))
{
substr_len = (unsigned char)*strptr;
if (strptr + substr_len + 1 > aptr + rr_len)
{
status = ARES_EBADRESP;
break;
}
/* Allocate storage for this TXT answer appending it to the list */
txt_curr = ares_malloc_data(ARES_DATATYPE_TXT_REPLY);
if (!txt_curr)
{
status = ARES_ENOMEM;
break;
}
if (txt_last)
{
txt_last->next = txt_curr;
}
else
{
txt_head = txt_curr;
}
txt_last = txt_curr;
txt_curr->record_start = strptr == aptr;
txt_curr->length = substr_len;
txt_curr->txt = malloc (substr_len + 1/* Including null byte */);
if (txt_curr->txt == NULL)
{
status = ARES_ENOMEM;
break;
}
++strptr;
memcpy ((char *) txt_curr->txt, strptr, substr_len);
/* Make sure we NULL-terminate */
txt_curr->txt[substr_len] = 0;
strptr += substr_len;
}
}
/* Don't lose memory in the next iteration */
free (rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
/* clean up on error */
if (status != ARES_SUCCESS)
{
if (txt_head)
ares_free_data (txt_head);
return status;
}
/* everything looks fine, return the data */
*txt_out = txt_head;
return ARES_SUCCESS;
}
inline static const unsigned char *CheckPatternAfterParseAnswer(struct DNSTask *dnstask, const unsigned char *aptr, const unsigned char *abuf, int alen) {
const unsigned char *p;
int type, dnsclass, ttl, dlen, status;
long len;
char addr[46];
/*
if (task->LObjId == 1148) raise(SIGTRAP);
*/
union {
unsigned char * as_uchar;
char * as_char;
} name;
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen) {
ares_free_string(name.as_char);
return NULL;
}
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
ares_free_string(name.as_char);
return NULL;
}
ares_free_string(name.as_char);
switch (type) {
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS) {
debug("error T_%s compare, %s andd ttl %d error - %d", type_name(type), dnstask->taskPattern, dnstask->taskTTL, status);
return NULL;
}
debug("T_%s compare, %s:%08x on %s and ttl %d on %d", type_name(type), dnstask->taskPattern, dnstask->taskPattern, name.as_char, ttl, dnstask->taskTTL);
if ((dnstask->taskPattern[0] == 0 or !memcmp(name.as_char, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
ares_free_string(name.as_char);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
debug("\t%.*s", (int) len, p + 1);
p += len + 1;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
debug("\t%.*s", (int) len, p + 1);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_MX:
if (dlen < 2) {
return NULL;
}
status = ares_expand_name(aptr + 2, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS) {
return NULL;
}
debug("T_MX compare %s on %s and ttl %d on %d\n", dnstask->taskPattern, name.as_char, ttl, dnstask->taskTTL);
if ((dnstask->taskPattern[0] = 0 or !memcmp(name.as_char, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
ares_free_string(name.as_char);
break;
case T_SOA:
/* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t\t\t\t\t\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
if (p + 20 > aptr + dlen)
return NULL;
debug("\t\t\t\t\t\t( %lu %lu %lu %lu %lu )",
(unsigned long) DNS__32BIT(p), (unsigned long) DNS__32BIT(p + 4),
(unsigned long) DNS__32BIT(p + 8), (unsigned long) DNS__32BIT(p + 12),
(unsigned long) DNS__32BIT(p + 16));
break;
case T_TXT:
/* The RR data is one or more length-counted character
* strings. */
p = aptr;
while (p < aptr + dlen) {
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
//printf("\t%.*s", (int) len, p + 1);
debug("T_TXT compare %s on %s and ttl %d on %d", dnstask->taskPattern, p + 1, ttl, dnstask->taskTTL);
if (!memcmp(p + 1, dnstask->taskPattern, dnstask->taskPatternLen) and ttl == dnstask->taskTTL) {
dnstask->task->code = STATE_DONE;
}
p += len + 1;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
inet_ntop(AF_INET, aptr, addr, sizeof (addr));
debug("T_A compare %s on %s (size %d) and ttl %d on %d", dnstask->taskPattern, addr, dnstask->taskPatternLen, ttl, dnstask->taskTTL);
/*
if (dnstask->task->LObjId == 1056) raise(SIGSEGV);
*/
if (dlen == 4 and(dnstask->taskPattern[0] == 0 or !memcmp(addr, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
break;
case T_AAAA:
/* The RR data is a 16-byte IPv6 address. */
if (dlen != 16)
return NULL;
debug("\t%s", inet_ntop(AF_INET6, aptr, addr, sizeof (addr)));
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
printf("\t%d", DNS__16BIT(aptr));
printf(" %d", DNS__16BIT(aptr + 2));
printf(" %d", DNS__16BIT(aptr + 4));
status = ares_expand_name(aptr + 6, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_NAPTR:
printf("\t%d", DNS__16BIT(aptr)); /* order */
printf(" %d\n", DNS__16BIT(aptr + 2)); /* preference */
p = aptr + 4;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s", name.as_char);
ares_free_string(name.as_char);
break;
default:
printf("\t[Unknown RR; cannot parse]");
break;
}
if (dnstask->task->code != STATE_DONE) {
return aptr + dlen;
} else {
return NULL;
}
}
static const unsigned char *parse_rr(const unsigned char *aptr, const unsigned char *abuf, int alen) {
char *name;
long len;
int status, type, dnsclass, dlen;
struct in_addr addr;
dbg("ca_tmpname: %s\n", ca_tmpname);
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand query name\n");
exit_code(2, __PRETTY_FUNCTION__, "failed to expand query name");
}
aptr += len;
if (aptr + NS_RRFIXEDSZ > abuf + alen) {
printf("error: not enough data in DNS answer 1\n");
free(name);
return NULL;
}
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += NS_RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
printf("error: not enough data in DNS answer 2\n");
free(name);
return NULL;
}
if (dnsclass != CARES_CLASS_C_IN) {
printf("error: unsupported dnsclass (%i) in DNS answer\n", dnsclass);
free(name);
return NULL;
}
if (type != CARES_TYPE_SRV && type != CARES_TYPE_A && type != CARES_TYPE_CNAME) {
printf("error: unsupported DNS response type (%i)\n", type);
free(name);
return NULL;
}
if (type == CARES_TYPE_SRV) {
free(name);
caport = DNS__16BIT(aptr + 4);
dbg("caport: %i\n", caport);
status = ares_expand_name(aptr + 6, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand SRV name\n");
return NULL;
}
dbg("SRV name: %s\n", name);
if (is_ip(name)) {
caadr = inet_addr(name);
free(name);
}
else {
ca_tmpname = name;
}
}
else if (type == CARES_TYPE_CNAME) {
if ((ca_tmpname != NULL) &&
(STRNCASECMP(ca_tmpname, name, strlen(ca_tmpname)) == 0)) {
ca_tmpname = malloc(strlen(name));
if (ca_tmpname == NULL) {
printf("error: failed to allocate memory\n");
exit_code(2, __PRETTY_FUNCTION__, "memory allocation failure");
}
strcpy(ca_tmpname, name);
free(name);
}
else {
free(name);
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand CNAME\n");
return NULL;
}
dbg("CNAME: %s\n", name);
if (is_ip(name)) {
caadr = inet_addr(name);
free(name);
}
else {
ca_tmpname = name;
}
}
}
else if (type == CARES_TYPE_A) {
if (dlen == 4 && STRNCASECMP(ca_tmpname, name, strlen(ca_tmpname)) == 0) {
memcpy(&addr, aptr, sizeof(struct in_addr));
caadr = addr.s_addr;
}
free(name);
}
return aptr + dlen;
}
int getaddress(char *host, int rport, int transport, struct addrinfo *ret) {
struct addrinfo *result;
struct addrinfo *res;
int error;
struct addrinfo hints = {
.ai_family = AF_UNSPEC,
.ai_socktype = transport == SIP_TCP_TRANSPORT ? SOCK_STREAM : SOCK_DGRAM
};
if (rport) {
char strport[INT_DIGITS10];
snprintf(strport, INT_DIGITS10, "%i", rport);
error = getaddrinfo(host, strport, &hints, &result);
} else {
error = getaddrinfo(host, "sip", &hints, &result);
}
/* resolve the domain name into a list of addresses */
if (error != 0) {
if (error == EAI_SYSTEM) {
perror("getaddrinfo");
} else {
fprintf(stderr, "error in getaddrinfo for %s: %s\n", host, gai_strerror(error));
}
return -1;
}
/* loop over all returned results and do inverse lookup */
for (res = result; res != NULL; res = res->ai_next) {
char hostname[NI_MAXHOST];
error = getnameinfo(res->ai_addr, res->ai_addrlen, hostname, NI_MAXHOST, NULL, 0, 0);
if (error != 0) {
fprintf(stderr, "error in getnameinfo: %s\n", gai_strerror(error));
continue;
} if (*hostname != '\0') {
memset(ret, 0, sizeof(struct addrinfo));
memcpy(ret, res, sizeof(struct addrinfo));
ret->ai_addr = malloc(res->ai_addrlen);
memcpy(ret->ai_addr, res->ai_addr, res->ai_addrlen);
break;
}
}
freeaddrinfo(result);
return 0;
}
#ifdef HAVE_CARES_H
static const unsigned char *parse_rr(const unsigned char *aptr, const unsigned char *abuf, int alen) {
char *name;
long len;
int status, type, dnsclass, dlen;
struct in_addr addr;
dbg("ca_tmpname: %s\n", ca_tmpname);
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand query name\n");
exit_code(2, __PRETTY_FUNCTION__, "failed to expand query name");
}
aptr += len;
if (aptr + NS_RRFIXEDSZ > abuf + alen) {
printf("error: not enough data in DNS answer 1\n");
free(name);
return NULL;
}
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += NS_RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
printf("error: not enough data in DNS answer 2\n");
free(name);
return NULL;
}
if (dnsclass != CARES_CLASS_C_IN) {
printf("error: unsupported dnsclass (%i) in DNS answer\n", dnsclass);
free(name);
return NULL;
}
if ((ca_tmpname == NULL && type != CARES_TYPE_SRV) ||
(ca_tmpname != NULL &&
(type != CARES_TYPE_A && type != CARES_TYPE_CNAME))) {
printf("error: unsupported DNS response type (%i)\n", type);
free(name);
return NULL;
}
if (type == CARES_TYPE_SRV) {
free(name);
caport = DNS__16BIT(aptr + 4);
dbg("caport: %i\n", caport);
status = ares_expand_name(aptr + 6, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand SRV name\n");
return NULL;
}
dbg("SRV name: %s\n", name);
if (is_ip(name)) {
caadr = inet_addr(name);
free(name);
}
else {
ca_tmpname = name;
}
}
else if (type == CARES_TYPE_CNAME) {
if ((ca_tmpname != NULL) &&
(STRNCASECMP(ca_tmpname, name, strlen(ca_tmpname)) == 0)) {
ca_tmpname = malloc(strlen(name));
if (ca_tmpname == NULL) {
printf("error: failed to allocate memory\n");
exit_code(2, __PRETTY_FUNCTION__, "memory allocation failure");
}
strcpy(ca_tmpname, name);
free(name);
}
else {
free(name);
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) {
printf("error: failed to expand CNAME\n");
return NULL;
}
dbg("CNAME: %s\n", name);
if (is_ip(name)) {
caadr = inet_addr(name);
free(name);
}
else {
ca_tmpname = name;
}
}
}
else if (type == CARES_TYPE_A) {
if (dlen == 4 && STRNCASECMP(ca_tmpname, name, strlen(ca_tmpname)) == 0) {
memcpy(&addr, aptr, sizeof(struct in_addr));
caadr = addr.s_addr;
}
free(name);
}
return aptr + dlen;
}
static int same_questions(const unsigned char *qbuf, int qlen,
const unsigned char *abuf, int alen)
{
struct {
const unsigned char *p;
int qdcount;
char *name;
long int namelen;
int type;
int dnsclass;
} q, a;
int i, j;
if (qlen < HFIXEDSZ || alen < HFIXEDSZ)
return 0;
/* Extract qdcount from the request and reply buffers and compare them. */
q.qdcount = DNS_HEADER_QDCOUNT(qbuf);
a.qdcount = DNS_HEADER_QDCOUNT(abuf);
if (q.qdcount != a.qdcount)
return 0;
/* For each question in qbuf, find it in abuf. */
q.p = qbuf + HFIXEDSZ;
for (i = 0; i < q.qdcount; i++)
{
/* Decode the question in the query. */
if (ares_expand_name(q.p, qbuf, qlen, &q.name, &q.namelen)
!= ARES_SUCCESS)
return 0;
q.p += q.namelen;
if (q.p + QFIXEDSZ > qbuf + qlen)
{
free(q.name);
return 0;
}
q.type = DNS_QUESTION_TYPE(q.p);
q.dnsclass = DNS_QUESTION_CLASS(q.p);
q.p += QFIXEDSZ;
/* Search for this question in the answer. */
a.p = abuf + HFIXEDSZ;
for (j = 0; j < a.qdcount; j++)
{
/* Decode the question in the answer. */
if (ares_expand_name(a.p, abuf, alen, &a.name, &a.namelen)
!= ARES_SUCCESS)
{
free(q.name);
return 0;
}
a.p += a.namelen;
if (a.p + QFIXEDSZ > abuf + alen)
{
free(q.name);
free(a.name);
return 0;
}
a.type = DNS_QUESTION_TYPE(a.p);
a.dnsclass = DNS_QUESTION_CLASS(a.p);
a.p += QFIXEDSZ;
/* Compare the decoded questions. */
if (strcasecmp(q.name, a.name) == 0 && q.type == a.type
&& q.dnsclass == a.dnsclass)
{
free(a.name);
break;
}
free(a.name);
}
free(q.name);
if (j == a.qdcount)
return 0;
}
return 1;
}
static int
ev_ares_parse_a_reply (const unsigned char *abuf, int alen,
struct ev_ares_a_reply **a_out)
{
unsigned int qdcount, ancount, i;
const unsigned char *aptr, *vptr;
int status, rr_type, rr_class, rr_len, rr_ttl, cname_ttl = INT_MAX;
int naddrs = 0, naliases = 0;
long len;
char *hostname = NULL, *rr_name = NULL, *rr_data = NULL;
struct ev_ares_a_reply *a_head = NULL;
struct ev_ares_a_reply *a_last = NULL;
struct ev_ares_a_reply *a_curr;
/* Set *a_out to NULL for all failure cases. */
*a_out = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT (abuf);
ancount = DNS_HEADER_ANCOUNT (abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_ENODATA;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free (hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
//cwarn("expanded name: %s",rr_name);
if (status != ARES_SUCCESS)
{
break;
}
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE (aptr);
rr_class = DNS_RR_CLASS (aptr);
rr_ttl = DNS_RR_TTL (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
/* Check if we are really looking at a A record */
if (rr_class == C_IN && rr_type == T_A) {
if ( rr_len == sizeof(struct in_addr) && strcasecmp(rr_name, hostname) == 0 ) {
if (aptr + sizeof(struct in_addr) > abuf + alen) {
status = ARES_EBADRESP;
break;
}
a_curr = calloc(1,sizeof(struct ev_ares_a_reply));
if (!a_curr)
{
status = ARES_ENOMEM;
break;
}
if (a_last)
{
a_last->next = a_curr;
}
else
{
a_head = a_curr;
}
a_last = a_curr;
a_curr->ttl = rr_ttl;
a_curr->host = rr_name;
rr_name = NULL;
memcpy(&a_curr->ip, aptr, sizeof(struct in_addr));
naddrs++;
}
}
else
if (rr_class == C_IN && rr_type == T_CNAME) {
naliases++;
status = ares_expand_name(aptr, abuf, alen, &rr_data, &len);
if (status != ARES_SUCCESS)
break;
if (cname_ttl > rr_ttl)
cname_ttl = rr_ttl;
free(hostname);
hostname = rr_data;
}
if (rr_name)
free(rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
if (status == ARES_SUCCESS && naddrs == 0 && naliases == 0)
/* the check for naliases to be zero is to make sure CNAME responses
don't get caught here */
status = ARES_ENODATA;
/* clean up on error */
if (status == ARES_SUCCESS)
{
if (naliases > 0) {
for (a_curr = a_head;a_curr;a_curr = a_curr->next)
{
if (a_curr->ttl > cname_ttl)
a_curr->ttl = cname_ttl;
}
}
}
else
{
if (a_head)
ev_ares_free_a_reply (a_head);
return status;
}
/* everything looks fine, return the data */
*a_out = a_head;
return ARES_SUCCESS;
}
int
ares_parse_mx_reply (const unsigned char *abuf, int alen,
struct ares_mx_reply **mx_out)
{
unsigned int qdcount, ancount, i;
const unsigned char *aptr, *vptr;
int status, rr_type, rr_class, rr_len;
long len;
char *hostname = NULL, *rr_name = NULL;
struct ares_mx_reply *mx_head = NULL;
struct ares_mx_reply *mx_last = NULL;
struct ares_mx_reply *mx_curr;
/* Set *mx_out to NULL for all failure cases. */
*mx_out = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT (abuf);
ancount = DNS_HEADER_ANCOUNT (abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_ENODATA;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free (hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
{
break;
}
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE (aptr);
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
/* Check if we are really looking at a MX record */
if (rr_class == C_IN && rr_type == T_MX)
{
/* parse the MX record itself */
if (rr_len < 2)
{
status = ARES_EBADRESP;
break;
}
/* Allocate storage for this MX answer appending it to the list */
mx_curr = ares_malloc_data(ARES_DATATYPE_MX_REPLY);
if (!mx_curr)
{
status = ARES_ENOMEM;
break;
}
if (mx_last)
{
mx_last->next = mx_curr;
}
else
{
mx_head = mx_curr;
}
mx_last = mx_curr;
vptr = aptr;
mx_curr->priority = DNS__16BIT(vptr);
vptr += sizeof(unsigned short);
status = ares_expand_name (vptr, abuf, alen, &mx_curr->host, &len);
if (status != ARES_SUCCESS)
break;
}
/* Don't lose memory in the next iteration */
free (rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
/* clean up on error */
if (status != ARES_SUCCESS)
{
if (mx_head)
ares_free_data (mx_head);
return status;
}
/* everything looks fine, return the data */
*mx_out = mx_head;
return ARES_SUCCESS;
}
int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
int addrlen, int family, struct hostent **host)
{
unsigned int qdcount, ancount;
int status, i, len, rr_type, rr_class, rr_len;
const unsigned char *aptr;
char *ptrname, *hostname, *rr_name, *rr_data;
struct hostent *hostent;
/* Set *host to NULL for all failure cases. */
*host = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1)
return ARES_EBADRESP;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name(aptr, abuf, alen, &ptrname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free(ptrname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
hostname = NULL;
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
break;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE(aptr);
rr_class = DNS_RR_CLASS(aptr);
rr_len = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (rr_class == C_IN && rr_type == T_PTR
&& strcasecmp(rr_name, ptrname) == 0)
{
/* Decode the RR data and set hostname to it. */
status = ares_expand_name(aptr, abuf, alen, &rr_data, &len);
if (status != ARES_SUCCESS)
break;
if (hostname)
free(hostname);
hostname = rr_data;
}
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Decode the RR data and replace ptrname with it. */
status = ares_expand_name(aptr, abuf, alen, &rr_data, &len);
if (status != ARES_SUCCESS)
break;
free(ptrname);
ptrname = rr_data;
}
free(rr_name);
aptr += rr_len;
if (aptr > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
}
if (status == ARES_SUCCESS && !hostname)
status = ARES_ENODATA;
if (status == ARES_SUCCESS)
{
/* We got our answer. Allocate memory to build the host entry. */
hostent = malloc(sizeof(struct hostent));
if (hostent)
{
hostent->h_addr_list = malloc(2 * sizeof(char *));
if (hostent->h_addr_list)
{
hostent->h_addr_list[0] = malloc(addrlen);
if (hostent->h_addr_list[0])
{
hostent->h_aliases = malloc(sizeof (char *));
if (hostent->h_aliases)
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
hostent->h_aliases[0] = NULL;
hostent->h_addrtype = family;
hostent->h_length = addrlen;
memcpy(hostent->h_addr_list[0], addr, addrlen);
hostent->h_addr_list[1] = NULL;
*host = hostent;
free(ptrname);
return ARES_SUCCESS;
}
free(hostent->h_addr_list[0]);
}
free(hostent->h_addr_list);
}
free(hostent);
}
status = ARES_ENOMEM;
}
if (hostname)
free(hostname);
free(ptrname);
return status;
}
