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;
}
}
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;
}
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_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 void callback(void *arg, int status, int timeouts,
unsigned char *abuf, int alen)
{
char *name = (char *) arg;
int id, qr, opcode, aa, tc, rd, ra, rcode;
unsigned int qdcount, ancount, nscount, arcount, i;
const unsigned char *aptr;
(void) timeouts;
/* Display the query name if given. */
if (name)
printf("Answer for query %s:\n", name);
/* Display an error message if there was an error, but only stop if
* we actually didn't get an answer buffer.
*/
if (status != ARES_SUCCESS)
{
printf("%s\n", ares_strerror(status));
if (!abuf)
return;
}
/* Won't happen, but check anyway, for safety. */
if (alen < HFIXEDSZ)
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);
/* Display the answer header. */
printf("id: %d\n", id);
printf("flags: %s%s%s%s%s\n",
qr ? "qr " : "",
aa ? "aa " : "",
tc ? "tc " : "",
rd ? "rd " : "",
ra ? "ra " : "");
printf("opcode: %d %s\n", opcode, opcodes[opcode]);
printf("rcode: %d %s\n", rcode, rcodes[rcode]);
printf("qdcount: %d\n", qdcount);
printf("ancount: %d\n", ancount);
printf("nscount: %d\n", nscount);
printf("arcount: %d\n", arcount);
/* Display the questions. */
printf("Questions:\n");
aptr = abuf + HFIXEDSZ;
for (i = 0; i < qdcount; i++)
{
aptr = display_question(aptr, abuf, alen);
if (aptr == NULL)
return;
}
/* Display the answers. */
printf("Answers:\n");
for (i = 0; i < ancount; i++)
{
aptr = display_rr(aptr, abuf, alen);
if (aptr == NULL)
return;
}
/* Display the NS records. */
printf("NS records:\n");
for (i = 0; i < nscount; i++)
{
aptr = display_rr(aptr, abuf, alen);
if (aptr == NULL)
return;
}
/* Display the additional records. */
printf("Additional records:\n");
for (i = 0; i < arcount; i++)
{
aptr = display_rr(aptr, abuf, alen);
if (aptr == NULL)
return;
}
}
void LLQueryResponder::queryResult(const char *buf, size_t len)
{
const char *pos = buf;
int qdcount = DNS_HEADER_QDCOUNT(pos);
int ancount = DNS_HEADER_ANCOUNT(pos);
int nscount = DNS_HEADER_NSCOUNT(pos);
int arcount = DNS_HEADER_ARCOUNT(pos);
int ret;
if (qdcount == 0 || ancount + nscount + arcount == 0)
{
ret = ARES_ENODATA;
goto bail;
}
pos += NS_HFIXEDSZ;
for (int i = 0; i < qdcount; i++)
{
std::string ignore;
size_t enclen;
ret = LLAres::expandName(pos, buf, len, i == 0 ? mQuery : ignore,
enclen);
if (ret != ARES_SUCCESS)
{
goto bail;
}
pos += enclen;
if (i == 0)
{
int t = DNS_QUESTION_TYPE(pos);
switch (t)
{
case RES_A:
case RES_NS:
case RES_CNAME:
case RES_PTR:
case RES_AAAA:
case RES_SRV:
mType = (LLResType) t;
break;
default:
LL_INFOS() << "Cannot grok query type " << t << LL_ENDL;
ret = ARES_EBADQUERY;
goto bail;
}
}
pos += NS_QFIXEDSZ;
if (pos > buf + len)
{
ret = ARES_EBADRESP;
goto bail;
}
}
ret = parseSection(buf, len, ancount, pos, mAnswers);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, nscount, pos, mAuthorities);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, arcount, pos, mAdditional);
bail:
mResult = ret;
if (mResult == ARES_SUCCESS)
{
querySuccess();
} else {
queryError(mResult);
}
}
void dns_detail_callback(void *arg, int status, int timeouts, unsigned char *abuf, int alen)
{
int id, qr, opcode, aa, tc, rd, ra, rcode;
unsigned int qdcount, ancount, nscount, arcount, i;
const unsigned char *aptr;
dns_resp_t *response = (dns_resp_t *) arg;
clearstrbuffer(response->msgbuf);
response->msgstatus = status;
/*
* Display an error message if there was an error, but only stop if
* we actually didn't get an answer buffer.
*/
switch (status) {
case ARES_SUCCESS:
break;
case ARES_ENODATA:
addtobuffer(response->msgbuf, "No data returned from server\n");
if (!abuf) return;
break;
case ARES_EFORMERR:
addtobuffer(response->msgbuf, "Server could not understand query\n");
if (!abuf) return;
break;
case ARES_ESERVFAIL:
addtobuffer(response->msgbuf, "Server failed\n");
if (!abuf) return;
break;
case ARES_ENOTFOUND:
addtobuffer(response->msgbuf, "Name not found\n");
if (!abuf) return;
break;
case ARES_ENOTIMP:
addtobuffer(response->msgbuf, "Not implemented\n");
if (!abuf) return;
break;
case ARES_EREFUSED:
addtobuffer(response->msgbuf, "Server refused query\n");
if (!abuf) return;
break;
case ARES_EBADNAME:
addtobuffer(response->msgbuf, "Invalid name in query\n");
if (!abuf) return;
break;
case ARES_ETIMEOUT:
addtobuffer(response->msgbuf, "Timeout\n");
if (!abuf) return;
break;
case ARES_ECONNREFUSED:
addtobuffer(response->msgbuf, "Server unavailable\n");
if (!abuf) return;
break;
case ARES_ENOMEM:
addtobuffer(response->msgbuf, "Out of memory\n");
if (!abuf) return;
break;
case ARES_EDESTRUCTION:
addtobuffer(response->msgbuf, "Timeout (channel destroyed)\n");
if (!abuf) return;
break;
default:
addtobuffer(response->msgbuf, "Undocumented ARES return code\n");
if (!abuf) return;
break;
}
/* Won't happen, but check anyway, for safety. */
if (alen < HFIXEDSZ) 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);
/* Display the answer header. */
sprintf(msg, "id: %d\n", id);
addtobuffer(response->msgbuf, msg);
sprintf(msg, "flags: %s%s%s%s%s\n",
qr ? "qr " : "",
aa ? "aa " : "",
tc ? "tc " : "",
rd ? "rd " : "",
ra ? "ra " : "");
addtobuffer(response->msgbuf, msg);
sprintf(msg, "opcode: %s\n", opcodes[opcode]);
addtobuffer(response->msgbuf, msg);
sprintf(msg, "rcode: %s\n", rcodes[rcode]);
addtobuffer(response->msgbuf, msg);
/* Display the questions. */
addtobuffer(response->msgbuf, "Questions:\n");
aptr = abuf + HFIXEDSZ;
for (i = 0; i < qdcount; i++) {
aptr = display_question(aptr, abuf, alen, response);
if (aptr == NULL) return;
}
/* Display the answers. */
addtobuffer(response->msgbuf, "Answers:\n");
for (i = 0; i < ancount; i++) {
aptr = display_rr(aptr, abuf, alen, response);
if (aptr == NULL) return;
}
/* Display the NS records. */
addtobuffer(response->msgbuf, "NS records:\n");
for (i = 0; i < nscount; i++) {
aptr = display_rr(aptr, abuf, alen, response);
if (aptr == NULL) return;
}
/* Display the additional records. */
addtobuffer(response->msgbuf, "Additional records:\n");
for (i = 0; i < arcount; i++) {
aptr = display_rr(aptr, abuf, alen, response);
if (aptr == NULL) return;
}
return;
}
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;
}
int
ares_parse_soa_reply(const unsigned char *abuf, int alen,
struct ares_soa_reply **soa_out)
{
const unsigned char *aptr;
long len;
char *qname = NULL, *rr_name = NULL;
struct ares_soa_reply *soa = NULL;
int qdcount, ancount;
int status;
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* parse message header */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1 || ancount != 1)
return ARES_EBADRESP;
aptr = abuf + HFIXEDSZ;
/* query name */
status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* skip qtype & qclass */
if (aptr + QFIXEDSZ > abuf + alen)
goto failed;
aptr += QFIXEDSZ;
/* rr_name */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* skip rr_type, rr_class, rr_ttl, rr_rdlen */
if (aptr + RRFIXEDSZ > abuf + alen)
goto failed;
aptr += RRFIXEDSZ;
/* allocate result struct */
soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
if (!soa)
{
status = ARES_ENOMEM;
goto failed_stat;
}
/* nsname */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* hostmaster */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->hostmaster, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* integer fields */
if (aptr + 5 * 4 > abuf + alen)
goto failed;
soa->serial = DNS__32BIT(aptr + 0 * 4);
soa->refresh = DNS__32BIT(aptr + 1 * 4);
soa->retry = DNS__32BIT(aptr + 2 * 4);
soa->expire = DNS__32BIT(aptr + 3 * 4);
soa->minttl = DNS__32BIT(aptr + 4 * 4);
free(qname);
free(rr_name);
*soa_out = soa;
return ARES_SUCCESS;
failed:
status = ARES_EBADRESP;
failed_stat:
ares_free_data(soa);
if (qname)
free(qname);
if (rr_name)
free(rr_name);
return status;
}
int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
struct hostent **host, struct ares_addr6ttl *addrttls,
int *naddrttls)
{
unsigned int qdcount, ancount;
int status, i, rr_type, rr_class, rr_len, rr_ttl, naddrs;
int cname_ttl = INT_MAX; /* the TTL imposed by the CNAME chain */
int naliases;
long len;
const unsigned char *aptr;
char *hostname, *rr_name, *rr_data, **aliases;
struct ares_in6_addr *addrs;
struct hostent *hostent;
const int max_addr_ttls = (addrttls && naddrttls) ? *naddrttls : 0;
/* Set *host to NULL for all failure cases. */
if (host)
*host = NULL;
/* Same with *naddrttls. */
if (naddrttls)
*naddrttls = 0;
/* 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_for_response(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 addresses and aliases; ancount gives an upper bound for both. */
if (host)
{
addrs = malloc(ancount * sizeof(struct ares_in6_addr));
if (!addrs)
{
free(hostname);
return ARES_ENOMEM;
}
aliases = malloc((ancount + 1) * sizeof(char *));
if (!aliases)
{
free(hostname);
free(addrs);
return ARES_ENOMEM;
}
}
else
{
addrs = NULL;
aliases = NULL;
}
naddrs = 0;
naliases = 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_for_response(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);
rr_ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
if (rr_class == C_IN && rr_type == T_AAAA
&& rr_len == sizeof(struct ares_in6_addr)
&& strcasecmp(rr_name, hostname) == 0)
{
if (addrs)
{
if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
memcpy(&addrs[naddrs], aptr, sizeof(struct ares_in6_addr));
}
if (naddrs < max_addr_ttls)
{
struct ares_addr6ttl * const at = &addrttls[naddrs];
if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
memcpy(&at->ip6addr, aptr, sizeof(struct ares_in6_addr));
at->ttl = rr_ttl;
}
naddrs++;
status = ARES_SUCCESS;
}
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Record the RR name as an alias. */
if (aliases)
aliases[naliases] = rr_name;
else
free(rr_name);
naliases++;
/* Decode the RR data and replace the hostname with it. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
break;
free(hostname);
hostname = rr_data;
/* Take the min of the TTLs we see in the CNAME chain. */
if (cname_ttl > rr_ttl)
cname_ttl = rr_ttl;
}
else
free(rr_name);
aptr += rr_len;
if (aptr > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
}
if (status == ARES_SUCCESS && naddrs == 0)
status = ARES_ENODATA;
if (status == ARES_SUCCESS)
{
/* We got our answer. */
if (naddrttls)
{
const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;
for (i = 0; i < n; i++)
{
/* Ensure that each A TTL is no larger than the CNAME TTL. */
if (addrttls[i].ttl > cname_ttl)
addrttls[i].ttl = cname_ttl;
}
*naddrttls = n;
}
if (aliases)
aliases[naliases] = NULL;
if (host)
{
/* Allocate memory to build the host entry. */
hostent = malloc(sizeof(struct hostent));
if (hostent)
{
hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *));
if (hostent->h_addr_list)
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
hostent->h_aliases = aliases;
hostent->h_addrtype = AF_INET6;
hostent->h_length = sizeof(struct ares_in6_addr);
for (i = 0; i < naddrs; i++)
hostent->h_addr_list[i] = (char *) &addrs[i];
hostent->h_addr_list[naddrs] = NULL;
*host = hostent;
return ARES_SUCCESS;
}
free(hostent);
}
status = ARES_ENOMEM;
}
}
if (aliases)
{
for (i = 0; i < naliases; i++)
free(aliases[i]);
free(aliases);
}
free(addrs);
free(hostname);
return status;
}
/* parse reply record */
int evdns_parse_reply(unsigned char *buf, int nbuf, HOSTENT *hostent)
{
unsigned char *p = NULL, *end = NULL, *s = NULL, *ps = NULL;
int i = 0, qdcount = 0, ancount = 0, nscount = 0, arcount = 0,
qr = 0, opcode = 0, aa = 0, tc = 0, rd = 0,
ra = 0, rcode = 0, type = 0, dnsclass = 0, ttl = 0, rrlen = 0;
if(buf && nbuf > HFIXEDSZ)
{
hostent->naddrs = 0;
hostent->nalias = 0;
p = buf;
end = buf + nbuf;
hostent->qid = DNS_HEADER_QID(p);
qr = DNS_HEADER_QR(p);
opcode = DNS_HEADER_OPCODE(p);
aa = DNS_HEADER_AA(p);
tc = DNS_HEADER_TC(p);
rd = DNS_HEADER_RD(p);
ra = DNS_HEADER_RA(p);
rcode = DNS_HEADER_RCODE(p);
qdcount = DNS_HEADER_QDCOUNT(p);
ancount = DNS_HEADER_ANCOUNT(p);
nscount = DNS_HEADER_NSCOUNT(p);
arcount = DNS_HEADER_ARCOUNT(p);
p += HFIXEDSZ;
/* Display the answer header. */
/*
printf("id: %d\n", id);
printf("flags: %s%s%s%s%s\n",
qr ? "qr " : "",
aa ? "aa " : "",
tc ? "tc " : "",
rd ? "rd " : "",
ra ? "ra " : "");
printf("opcode: %s\n", opcodes[opcode]);
printf("rcode: %s\n", rcodes[rcode]);
fprintf(stdout, "qdcount:%d\nancount:%d\nnscount:%d\narcount:%d\n",
qdcount, ancount, nscount, arcount);
*/
/* parse question */
for(i = 0; i < qdcount; i++)
{
ps = (unsigned char *)hostent->name;
p = evdns_expand_name(p, buf, end, ps);
/* Parse the question type and class. */
type = DNS_QUESTION_TYPE(p);
dnsclass = DNS_QUESTION_CLASS(p);
p += QFIXEDSZ;
/*
fprintf(stdout, "qname:%-15s", name);
fprintf(stdout, "\tqtype:%d", type);
fprintf(stdout, "\tqclass:%d\r\n", dnsclass);
*/
}
/* parse A name */
for(i = 0; i < ancount; i++)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
p = evdns_expand_name(p, buf, end, ps);
type = DNS_RR_TYPE(p);
dnsclass = DNS_RR_CLASS(p);
ttl = DNS_RR_TTL(p);
rrlen = DNS_RR_LEN(p);
p += RRFIXEDSZ;
/*
fprintf(stdout, "name:%s type:%d dnsclass:%d ttl:%d rrlen:%d ",
name, type, dnsclass, ttl, rrlen);
*/
/* addr name */
if(type == TYPE_ANAME)
{
hostent->addrs[hostent->naddrs++] = *((int *)p);
}
/* Canonical name */
else if(type == TYPE_CNAME)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
s = evdns_expand_name(p, buf, end, ps);
//fprintf(stdout, "cname:%s ", cname);
}
/* pointer */
else if(type == TYPE_PTR)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
s = evdns_expand_name(p, buf, end, ps);
//fprintf(stdout, "pointer:%s ", cname);
}
//fprintf(stdout, "\r\n");
p += rrlen;
}
return 0;
}
return -1;
}
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;
}
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, rr_type, rr_class, rr_len;
long len;
const unsigned char *aptr;
char *ptrname, *hostname, *rr_name, *rr_data;
struct hostent *hostent;
int aliascnt = 0;
int alias_alloc = 8;
char ** aliases;
/* 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_for_response(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;
aliases = malloc(alias_alloc * sizeof(char *));
if (!aliases)
{
free(ptrname);
return ARES_ENOMEM;
}
for (i = 0; i < (int)ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
break;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
free(rr_name);
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_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
{
free(rr_name);
break;
}
if (hostname)
free(hostname);
hostname = rr_data;
aliases[aliascnt] = malloc((strlen(rr_data)+1) * sizeof(char));
if (!aliases[aliascnt])
{
free(rr_name);
status = ARES_ENOMEM;
break;
}
strncpy(aliases[aliascnt], rr_data, strlen(rr_data)+1);
aliascnt++;
if (aliascnt >= alias_alloc) {
char **ptr;
alias_alloc *= 2;
ptr = realloc(aliases, alias_alloc * sizeof(char *));
if(!ptr) {
free(rr_name);
status = ARES_ENOMEM;
break;
}
aliases = ptr;
}
}
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Decode the RR data and replace ptrname with it. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
{
free(rr_name);
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((aliascnt+1) * sizeof (char *));
if (hostent->h_aliases)
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
for (i=0 ; i<aliascnt ; i++)
hostent->h_aliases[i] = aliases[i];
hostent->h_aliases[aliascnt] = NULL;
hostent->h_addrtype = aresx_sitoss(family);
hostent->h_length = aresx_sitoss(addrlen);
memcpy(hostent->h_addr_list[0], addr, addrlen);
hostent->h_addr_list[1] = NULL;
*host = hostent;
free(aliases);
free(ptrname);
return ARES_SUCCESS;
}
free(hostent->h_addr_list[0]);
}
free(hostent->h_addr_list);
}
free(hostent);
}
status = ARES_ENOMEM;
}
for (i=0 ; i<aliascnt ; i++)
if (aliases[i])
free(aliases[i]);
free(aliases);
if (hostname)
free(hostname);
free(ptrname);
return status;
}
