Some DNS response may be valid from a protocol point of view but may not
contain any IP addresses.
This patch gives a new flag to the function dns_get_ip_from_response to
report such case.
It's up to the upper layer to decide what to do with this information.
Some DNS responses may be valid from a protocol point of view, but may
not contain any information considered as interested by the requester..
Purpose of the flag DNS_RESP_NO_EXPECTED_RECORD introduced by this patch is
to allow reporting such situation.
When this happens, a new DNS query is sent with a new query type.
For now, the function only expect A and AAAA query types which is enough
to cover current cases.
In a next future, it will be up to the caller to tell the function which
query types are expected.
This patch introduces a new internal response state about the analysis
of a DNS response received by a server.
It is dedicated to report to above layer that the response is
'truncated'.
This patch updates the dns_nameserver structure to integrate a counter
dedicated to 'truncated' response sent by servers.
Such response are important to track, since HAProxy is supposed to
replay its request.
Current DNS client code implementation doesn't take care of response
flags setup by the server.
This patch introduces a couple of bitmasks one can use to retrieve the
truncated flag and the reply code available in the 2-bytes flag field.
3 variables of the dns_resolution structure are set to 'time_t' type.
Since they are all set by 'now_ms' and used as 'ticks' in HAProxy's
internal, it is safer to set them to the same type than now_ms:
'unsigned int'.
Implementation of a DNS client in HAProxy to perform name resolution to
IP addresses.
It relies on the freshly created UDP client to perform the DNS
resolution. For now, all UDP socket calls are performed in the
DNS layer, but this might change later when the protocols are
extended to be more suited to datagram mode.
A new section called 'resolvers' is introduced thanks to this patch. It
is used to describe DNS servers IP address and also many parameters.
