The current DNS caching logic is not aware of the IP address version.
If there is a cached address for a query, the caller of
dns_get_addr_info() will receive that address, even if it is not the
same version as the caller requested. For example:
- dns_get_addr_info() is called to resolve an IPv4 address
- the DNS client caches the IPv4 address that was received
- dns_get_addr_info() is called to resolve an IPv6 address
- the DNS client sees that there is a cached IPv4 address for the
given query
- the DNS client does not check that the cached address is of the
requested version (IPv6)
- the cached IPv4 address is returned from dns_get_addr_info()
This changes the DNS client to check IP address version when searching
cached addresses.
Signed-off-by: Noah Olson <noah@wavelynx.com>
In order to reduce dns resolve requests when using the dns
resolver an optional cache was introduced. This cache
retains query requests for the TTL duration and therefore
prevents premature refetching of DNS RRs.
Signed-off-by: Carlo Kirchmeier <carlo.kirchmeier@zuehlke.com>
