static void next_lookup(struct host_query *hquery)
{
int status;
const char *p;
struct hostent *host;
for (p = hquery->remaining_lookups; *p; p++)
{
switch (*p)
{
case 'b':
/* DNS lookup */
hquery->remaining_lookups = p + 1;
ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
hquery);
return;
case 'f':
/* Host file lookup */
status = file_lookup(hquery->name, &host);
if (status != ARES_ENOTFOUND)
{
end_hquery(hquery, status, host);
return;
}
break;
}
}
end_hquery(hquery, ARES_ENOTFOUND, NULL);
}
static void host_callback(void *arg, int status, int timeouts,
unsigned char *abuf, int alen)
{
struct host_query *hquery = (struct host_query *) arg;
ares_channel channel = hquery->channel;
struct hostent *host = NULL;
hquery->timeouts += timeouts;
if (status == ARES_SUCCESS)
{
if (hquery->sent_family == AF_INET)
{
status = ares_parse_a_reply(abuf, alen, &host, NULL, NULL);
if (host && channel->nsort)
sort_addresses(host, channel->sortlist, channel->nsort);
}
else if (hquery->sent_family == AF_INET6)
{
status = ares_parse_aaaa_reply(abuf, alen, &host, NULL, NULL);
if ((status == ARES_ENODATA || status == ARES_EBADRESP ||
(status == ARES_SUCCESS && host && host->h_addr_list[0] == NULL)) &&
hquery->want_family == AF_UNSPEC) {
/* The query returned something but either there were no AAAA
records (e.g. just CNAME) or the response was malformed. Try
looking up A instead. */
if (host)
ares_free_hostent(host);
hquery->sent_family = AF_INET;
ares_search(hquery->channel, hquery->name, C_IN, T_A,
host_callback, hquery);
return;
}
if (host && channel->nsort)
sort6_addresses(host, channel->sortlist, channel->nsort);
}
end_hquery(hquery, status, host);
}
else if ((status == ARES_ENODATA || status == ARES_EBADRESP ||
status == ARES_ETIMEOUT) && (hquery->sent_family == AF_INET6 &&
hquery->want_family == AF_UNSPEC))
{
/* The AAAA query yielded no useful result. Now look up an A instead. */
hquery->sent_family = AF_INET;
ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
hquery);
}
else if (status == ARES_EDESTRUCTION)
end_hquery(hquery, status, NULL);
else
next_lookup(hquery, status);
}
static void next_lookup(struct host_query *hquery, int status_code)
{
const char *p;
struct hostent *host;
int status = status_code;
for (p = hquery->remaining_lookups; *p; p++)
{
switch (*p)
{
case 'b':
/* DNS lookup */
hquery->remaining_lookups = p + 1;
if ((hquery->want_family == AF_INET6) ||
(hquery->want_family == AF_UNSPEC)) {
/* if inet6 or unspec, start out with AAAA */
hquery->sent_family = AF_INET6;
ares_search(hquery->channel, hquery->name, C_IN, T_AAAA,
host_callback, hquery);
}
else {
hquery->sent_family = AF_INET;
ares_search(hquery->channel, hquery->name, C_IN, T_A,
host_callback, hquery);
}
return;
case 'f':
/* Host file lookup */
status = file_lookup(hquery->name, hquery->want_family, &host);
/* this status check below previously checked for !ARES_ENOTFOUND,
but we should not assume that this single error code is the one
that can occur, as that is in fact no longer the case */
if (status == ARES_SUCCESS)
{
end_hquery(hquery, status, host);
return;
}
status = status_code; /* Use original status code */
break;
}
}
end_hquery(hquery, status, NULL);
}
static void host_callback(void *arg, int status, unsigned char *abuf, int alen)
{
struct host_query *hquery = (struct host_query *) arg;
ares_channel channel = hquery->channel;
struct hostent *host;
if (status == ARES_SUCCESS)
{
status = ares_parse_a_reply(abuf, alen, &host);
if (host && channel->nsort)
sort_addresses(host, channel->sortlist, channel->nsort);
end_hquery(hquery, status, host);
}
else if (status == ARES_EDESTRUCTION)
end_hquery(hquery, status, NULL);
else
next_lookup(hquery);
}
