erldns

%% Copyright (c) 2012-2018, DNSimple Corporation
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

%% Functions related to DNS records.
-module(erldns_records).

-include("erldns.hrl").
-include_lib("dns_erlang/include/dns.hrl").
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.

-export([optionally_convert_wildcard/2, wildcard_qname/1]).
-export([default_ttl/1, default_priority/1, name_type/1, root_hints/0]).
-export([minimum_soa_ttl/2, rewrite_soa_ttl/1]).
-export([match_name/1, match_type/1, match_name_and_type/2, match_types/1, match_wildcard/0, match_delegation/1, match_type_covered/1]).
-export([replace_name/1]).

%% If the name returned from the DB is a wildcard name then the
%% Original Qname needs to be returned in its place.
optionally_convert_wildcard(Name, Qname) ->
  [Head|_] = dns:dname_to_labels(Name),
  case Head of
    <<"*">> -> Qname;
    _ -> Name
  end.

%% @doc Get a wildcard variation of a Qname. Replaces the leading
%% label with an asterisk for wildcard lookup.
-spec wildcard_qname(dns:dname()) -> dns:dname().
wildcard_qname(Qname) ->
  [_|Rest] = dns:dname_to_labels(Qname),
  dns:labels_to_dname([<<"*">>] ++ Rest).

%% @doc Return the TTL value or 3600 if it is undefined.
default_ttl(TTL) ->
  case TTL of
    undefined -> 3600;
    Value -> Value
  end.

%% @doc Return the Priority value or 0 if it is undefined.
default_priority(Priority) ->
  case Priority of
    undefined -> 0;
    Value -> Value
  end.

%% @doc Applies a minimum TTL based on the SOA minumum value.
%%
%% The first argument is the Record that is being updated.
%% The second argument is the SOA RR Data.
-spec minimum_soa_ttl(dns:dns_rr(), dns:dns_rrdata_soa()) -> dns:dns_rr().
minimum_soa_ttl(Record, Data) when is_record(Data, dns_rrdata_soa) -> Record#dns_rr{ttl = erlang:min(Data#dns_rrdata_soa.minimum, Record#dns_rr.ttl)};
minimum_soa_ttl(Record, _) -> Record.

%% According to RFC 2308 the TTL for the SOA record in an NXDOMAIN response
%% must be set to the value of the minimum field in the SOA content.
rewrite_soa_ttl(Message) -> rewrite_soa_ttl(Message, Message#dns_message.authority, []).
rewrite_soa_ttl(Message, [], NewAuthority) -> Message#dns_message{authority = NewAuthority};
rewrite_soa_ttl(Message, [R|Rest], NewAuthority) -> rewrite_soa_ttl(Message, Rest, NewAuthority ++ [minimum_soa_ttl(R, R#dns_rr.data)]).


%% Various matching functions.
match_name(Name) ->
  fun(R) when is_record(R, dns_rr) ->
      R#dns_rr.name =:= Name
  end.

match_type(Type) ->
  fun(R) when is_record(R, dns_rr) ->
      R#dns_rr.type =:= Type
  end.

match_name_and_type(Name, Type) ->
  fun(R) when is_record(R, dns_rr) ->
      (R#dns_rr.name =:= Name) and (R#dns_rr.type =:= Type)
  end.

match_types(Types) ->
  fun(R) when is_record(R, dns_rr) ->
      lists:any(fun(T) -> R#dns_rr.type =:= T end, Types)
  end.

match_wildcard() ->
  fun(R) when is_record(R, dns_rr) ->
      lists:any(match_wildcard_label(), dns:dname_to_labels(R#dns_rr.name))
  end.

match_wildcard_label() ->
  fun(L) ->
      L =:= <<"*">>
  end.

match_delegation(Name) ->
  fun(R) when is_record(R, dns_rr) ->
      R#dns_rr.data =:= #dns_rrdata_ns{dname=Name}
  end.

-spec(match_type_covered(dns:type()) -> fun((dns:rr()) -> boolean())).
match_type_covered(Qtype) ->
  fun(RRSig) ->
      RRSig#dns_rr.data#dns_rrdata_rrsig.type_covered =:= Qtype
  end.


%% Replacement functions.
replace_name(Name) -> fun(R) when is_record(R, dns_rr) -> R#dns_rr{name = Name} end.

%% @doc Returns the type value given a binary string.
-spec name_type(binary()) -> dns:type() | 'undefined'.
name_type(Type) when is_binary(Type) ->
  case Type of
    ?DNS_TYPE_A_BSTR -> ?DNS_TYPE_A_NUMBER;
    ?DNS_TYPE_NS_BSTR -> ?DNS_TYPE_NS_NUMBER;
    ?DNS_TYPE_MD_BSTR -> ?DNS_TYPE_MD_NUMBER;
    ?DNS_TYPE_MF_BSTR -> ?DNS_TYPE_MF_NUMBER;
    ?DNS_TYPE_CNAME_BSTR -> ?DNS_TYPE_CNAME_NUMBER;
    ?DNS_TYPE_SOA_BSTR -> ?DNS_TYPE_SOA_NUMBER;
    ?DNS_TYPE_MB_BSTR -> ?DNS_TYPE_MB_NUMBER;
    ?DNS_TYPE_MG_BSTR -> ?DNS_TYPE_MG_NUMBER;
    ?DNS_TYPE_MR_BSTR -> ?DNS_TYPE_MR_NUMBER;
    ?DNS_TYPE_NULL_BSTR -> ?DNS_TYPE_NULL_NUMBER;
    ?DNS_TYPE_WKS_BSTR -> ?DNS_TYPE_WKS_NUMBER;
    ?DNS_TYPE_PTR_BSTR -> ?DNS_TYPE_PTR_NUMBER;
    ?DNS_TYPE_HINFO_BSTR -> ?DNS_TYPE_HINFO_NUMBER;
    ?DNS_TYPE_MINFO_BSTR -> ?DNS_TYPE_MINFO_NUMBER;
    ?DNS_TYPE_MX_BSTR -> ?DNS_TYPE_MX_NUMBER;
    ?DNS_TYPE_TXT_BSTR -> ?DNS_TYPE_TXT_NUMBER;
    ?DNS_TYPE_RP_BSTR -> ?DNS_TYPE_RP_NUMBER;
    ?DNS_TYPE_AFSDB_BSTR -> ?DNS_TYPE_AFSDB_NUMBER;
    ?DNS_TYPE_X25_BSTR -> ?DNS_TYPE_X25_NUMBER;
    ?DNS_TYPE_ISDN_BSTR -> ?DNS_TYPE_ISDN_NUMBER;
    ?DNS_TYPE_RT_BSTR -> ?DNS_TYPE_RT_NUMBER;
    ?DNS_TYPE_NSAP_BSTR -> ?DNS_TYPE_NSAP_NUMBER;
    ?DNS_TYPE_SIG_BSTR -> ?DNS_TYPE_SIG_NUMBER;
    ?DNS_TYPE_KEY_BSTR -> ?DNS_TYPE_KEY_NUMBER;
    ?DNS_TYPE_PX_BSTR -> ?DNS_TYPE_PX_NUMBER;
    ?DNS_TYPE_GPOS_BSTR -> ?DNS_TYPE_GPOS_NUMBER;
    ?DNS_TYPE_AAAA_BSTR -> ?DNS_TYPE_AAAA_NUMBER;
    ?DNS_TYPE_LOC_BSTR -> ?DNS_TYPE_LOC_NUMBER;
    ?DNS_TYPE_NXT_BSTR -> ?DNS_TYPE_NXT_NUMBER;
    ?DNS_TYPE_EID_BSTR -> ?DNS_TYPE_EID_NUMBER;
    ?DNS_TYPE_NIMLOC_BSTR -> ?DNS_TYPE_NIMLOC_NUMBER;
    ?DNS_TYPE_SRV_BSTR -> ?DNS_TYPE_SRV_NUMBER;
    ?DNS_TYPE_ATMA_BSTR -> ?DNS_TYPE_ATMA_NUMBER;
    ?DNS_TYPE_NAPTR_BSTR -> ?DNS_TYPE_NAPTR_NUMBER;
    ?DNS_TYPE_KX_BSTR -> ?DNS_TYPE_KX_NUMBER;
    ?DNS_TYPE_CERT_BSTR -> ?DNS_TYPE_CERT_NUMBER;
    ?DNS_TYPE_DNAME_BSTR -> ?DNS_TYPE_DNAME_NUMBER;
    ?DNS_TYPE_SINK_BSTR -> ?DNS_TYPE_SINK_NUMBER;
    ?DNS_TYPE_OPT_BSTR -> ?DNS_TYPE_OPT_NUMBER;
    ?DNS_TYPE_APL_BSTR -> ?DNS_TYPE_APL_NUMBER;
    ?DNS_TYPE_DS_BSTR -> ?DNS_TYPE_DS_NUMBER;
    ?DNS_TYPE_CDS_BSTR -> ?DNS_TYPE_CDS_NUMBER;
    ?DNS_TYPE_SSHFP_BSTR -> ?DNS_TYPE_SSHFP_NUMBER;
    ?DNS_TYPE_IPSECKEY_BSTR -> ?DNS_TYPE_IPSECKEY_NUMBER;
    ?DNS_TYPE_RRSIG_BSTR -> ?DNS_TYPE_RRSIG_NUMBER;
    ?DNS_TYPE_NSEC_BSTR -> ?DNS_TYPE_NSEC_NUMBER;
    ?DNS_TYPE_DNSKEY_BSTR -> ?DNS_TYPE_DNSKEY_NUMBER;
    ?DNS_TYPE_CDNSKEY_BSTR -> ?DNS_TYPE_CDNSKEY_NUMBER;
    ?DNS_TYPE_NSEC3_BSTR -> ?DNS_TYPE_NSEC3_NUMBER;
    ?DNS_TYPE_NSEC3PARAM_BSTR -> ?DNS_TYPE_NSEC3PARAM_NUMBER;
    ?DNS_TYPE_DHCID_BSTR -> ?DNS_TYPE_DHCID_NUMBER;
    ?DNS_TYPE_HIP_BSTR -> ?DNS_TYPE_HIP_NUMBER;
    ?DNS_TYPE_NINFO_BSTR -> ?DNS_TYPE_NINFO_NUMBER;
    ?DNS_TYPE_RKEY_BSTR -> ?DNS_TYPE_RKEY_NUMBER;
    ?DNS_TYPE_TALINK_BSTR -> ?DNS_TYPE_TALINK_NUMBER;
    ?DNS_TYPE_SPF_BSTR -> ?DNS_TYPE_SPF_NUMBER;
    ?DNS_TYPE_UINFO_BSTR -> ?DNS_TYPE_UINFO_NUMBER;
    ?DNS_TYPE_UID_BSTR -> ?DNS_TYPE_UID_NUMBER;
    ?DNS_TYPE_GID_BSTR -> ?DNS_TYPE_GID_NUMBER;
    ?DNS_TYPE_UNSPEC_BSTR -> ?DNS_TYPE_UNSPEC_NUMBER;
    ?DNS_TYPE_TKEY_BSTR -> ?DNS_TYPE_TKEY_NUMBER;
    ?DNS_TYPE_TSIG_BSTR -> ?DNS_TYPE_TSIG_NUMBER;
    ?DNS_TYPE_IXFR_BSTR -> ?DNS_TYPE_IXFR_NUMBER;
    ?DNS_TYPE_AXFR_BSTR -> ?DNS_TYPE_AXFR_NUMBER;
    ?DNS_TYPE_MAILB_BSTR -> ?DNS_TYPE_MAILB_NUMBER;
    ?DNS_TYPE_MAILA_BSTR -> ?DNS_TYPE_MAILA_NUMBER;
    ?DNS_TYPE_ANY_BSTR -> ?DNS_TYPE_ANY_NUMBER;
    ?DNS_TYPE_CAA_BSTR -> ?DNS_TYPE_CAA_NUMBER;
    ?DNS_TYPE_DLV_BSTR -> ?DNS_TYPE_DLV_NUMBER;
    _ -> undefined
  end.

root_hints() ->
  {
   [
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"a.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"b.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"c.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"d.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"e.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"f.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"g.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"h.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"i.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"j.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"k.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"l.root-servers.net">>}},
    #dns_rr{name = <<"">>, type=?DNS_TYPE_NS, ttl=518400, data = #dns_rrdata_ns{dname = <<"m.root-servers.net">>}}
   ],
   [
    #dns_rr{name = <<"a.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {198,41,0,4}}},
    #dns_rr{name = <<"b.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,228,79,201}}},
    #dns_rr{name = <<"c.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,33,4,12}}},
    #dns_rr{name = <<"d.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {128,8,10,90}}},
    #dns_rr{name = <<"e.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,203,230,10}}},
    #dns_rr{name = <<"f.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,5,5,241}}},
    #dns_rr{name = <<"g.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,112,36,4}}},
    #dns_rr{name = <<"h.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {128,63,2,53}}},
    #dns_rr{name = <<"i.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,36,148,17}}},
    #dns_rr{name = <<"j.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {192,58,128,30}}},
    #dns_rr{name = <<"k.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {193,0,14,129}}},
    #dns_rr{name = <<"l.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {198,32,64,12}}},
    #dns_rr{name = <<"m.root-servers.net">>, type=?DNS_TYPE_A, ttl=3600000, data = #dns_rrdata_a{ip = {202,12,27,33}}}
   ]
  }.



-ifdef(TEST).

wildcard_qname_test_() ->
  ?_assertEqual(<<"*.b.example.com">>, wildcard_qname(<<"a.b.example.com">>)).

minimum_soa_ttl_test_() ->
  [
   ?_assertMatch(#dns_rr{ttl = 3600}, minimum_soa_ttl(#dns_rr{ttl = 3600}, #dns_rrdata_a{})),
   ?_assertMatch(#dns_rr{ttl = 30}, minimum_soa_ttl(#dns_rr{ttl = 3600}, #dns_rrdata_soa{minimum = 30})),
   ?_assertMatch(#dns_rr{ttl = 30}, minimum_soa_ttl(#dns_rr{ttl = 30}, #dns_rrdata_soa{minimum = 3600}))
  ].

replace_name_test_() ->
  [
   ?_assertEqual([], lists:map(replace_name(<<"example">>), [])),
   ?_assertMatch([#dns_rr{name = <<"example">>}], lists:map(replace_name(<<"example">>), [#dns_rr{name = <<"test.com">>}]))
  ].

match_name_test_() ->
  [
   ?_assert(lists:any(match_name(<<"example.com">>), [#dns_rr{name = <<"example.com">>}])),
   ?_assertNot(lists:any(match_name(<<"example.com">>), [#dns_rr{name = <<"example.net">>}]))
  ].

match_type_test_() ->
  [
   ?_assert(lists:any(match_type(?DNS_TYPE_A), [#dns_rr{type = ?DNS_TYPE_A}])),
   ?_assertNot(lists:any(match_type(?DNS_TYPE_CNAME), [#dns_rr{type = ?DNS_TYPE_A}]))
  ].

match_types_test_() ->
  [
   ?_assert(lists:any(match_types([?DNS_TYPE_A]), [#dns_rr{type = ?DNS_TYPE_A}])),
   ?_assert(lists:any(match_types([?DNS_TYPE_A, ?DNS_TYPE_CNAME]), [#dns_rr{type = ?DNS_TYPE_A}])),
   ?_assertNot(lists:any(match_types([?DNS_TYPE_CNAME]), [#dns_rr{type = ?DNS_TYPE_A}]))
  ].

match_wildcard_test_() ->
  [
   ?_assert(lists:any(match_wildcard(), [#dns_rr{name = <<"*.example.com">>}])),
   ?_assertNot(lists:any(match_wildcard(), [#dns_rr{name = <<"www.example.com">>}]))
  ].

match_delegation_test_() ->
  [
   ?_assert(lists:any(match_delegation(<<"ns1.example.com">>), [#dns_rr{data = #dns_rrdata_ns{dname = <<"ns1.example.com">>}}])),
   ?_assertNot(lists:any(match_delegation(<<"ns1.example.com">>), [#dns_rr{data = #dns_rrdata_ns{dname = <<"ns2.example.com">>}}]))
  ].

match_wildcard_label_test_() ->
  [
   ?_assert(lists:any(match_wildcard_label(), dns:dname_to_labels(<<"*.example.com">>))),
   ?_assertNot(lists:any(match_wildcard_label(), dns:dname_to_labels(<<"www.example.com">>)))
  ].

-endif.