Initial commit for dns cache per interface.
Added a type that holds a reference to a
cache and name of associated interface,
address of interface, name server(s)
associated with an interface etc.
New functions to set default interface,
address of name servers etc.
Change-Id: Ie991bc5592fd998409853d8bf77d7fe69035dac5
Use system property ro.net.dns_cache_size to set
the size of the cache. If the system property
is not set the default cache size is defined by
CONFIG_MAX_ENTRIES.
The number of entries in the hash table will be equal
to the number of max entries allowed in the cache.
Change-Id: I77d69d7c178937fa483d0b40512483ad29232d28
Use the the TTL of the answer as the time a query
shall remain in the resolver cache.
Added some debugging support as well, i.e.
parse answer and print a la dig.
Change-Id: I724d3392245032592f1912f3ca7a81a8987ebbac
The problem was that the 'defdname' field of res_state structure
was not properly initialized in __res_vinit(). This field is used
to store the default domain name, which is normally build from
calling gethostname() (see line 549 of res_init.c).
Unfortunately, in the typical Android case, gethostname() returns
an error (the hostname is configured) and a random stack string is
used later to build the DNS search list (see lines 556+ in res_init.c)
For the sake of illustration, let's say the search list is set to
a random value like 'xWLK'.
The end result is that when trying to result an unknown domain name
(e.g. 'www.ptn'), the query fails then the resolver tries to make a
new query with the DNS search list path(s) appended (e.g. 'www.ptn.xWLK').
The patch simply initializes 'defdname' to an empty string to avoid
this when the net.dns.search system property is not set.
Also contains whitespace/formatting fixes
