File 7351-Add-inet_dns-decode-2-and-inet_dns-encode-2.patch of Package erlang
From 1843057b974e5a856024923a8405e9ce27399624 Mon Sep 17 00:00:00 2001
From: Raimo Niskanen <raimo@erlang.org>
Date: Fri, 24 Nov 2023 14:00:24 +0100
Subject: [PATCH] Add `inet_dns:decode/2` and `inet_dns:encode/2`
Add new functions that take an option to indicate
if encode/decode should be for mDNS, since it affects
the value range for the CLASS to 15 or 16 bits.
---
lib/kernel/src/inet_dns.erl | 167 ++++++++++++++-----------
lib/kernel/src/inet_dns_record_adts.pl | 8 +-
lib/kernel/src/inet_res.erl | 4 +-
lib/kernel/test/inet_res_SUITE.erl | 81 +++++++++++-
4 files changed, 180 insertions(+), 80 deletions(-)
diff --git a/lib/kernel/src/inet_dns.erl b/lib/kernel/src/inet_dns.erl
index c65546a7e5..94598905be 100644
--- a/lib/kernel/src/inet_dns.erl
+++ b/lib/kernel/src/inet_dns.erl
@@ -35,7 +35,7 @@
%% RFC 7553: The Uniform Resource Identifier (URI) DNS Resource Record
%% RFC 8945: Secret Key Transaction Authentication for DNS (TSIG)
--export([decode/1, encode/1]).
+-export([decode/1, decode/2, encode/1, encode/2]).
-export([decode_algname/1, encode_algname/1]).
-import(lists, [reverse/1]).
@@ -148,8 +148,10 @@ lists_member(H, [_|T]) -> lists_member(H, T).
throw(?DECODE_ERROR)
end).
-decode(Buffer) when is_binary(Buffer) ->
- try do_decode(Buffer) of
+decode(Buffer) -> decode(Buffer, true). % Backwards compatible
+%%
+decode(Buffer, Mdns) when is_binary(Buffer), is_boolean(Mdns) ->
+ try do_decode(Buffer, Mdns) of
DnsRec ->
{ok,DnsRec}
catch
@@ -161,11 +163,14 @@ do_decode(<<Id:16,
QR:1,Opcode:4,AA:1,TC:1,RD:1,
RA:1,PR:1,_:2,Rcode:4,
QdCount:16,AnCount:16,NsCount:16,ArCount:16,
- QdBuf/binary>>=Buffer) ->
- {AnBuf,QdList,QdTC} = decode_query_section(QdBuf,QdCount,Buffer),
- {NsBuf,AnList,AnTC} = decode_rr_section(Opcode,AnBuf,AnCount,Buffer),
- {ArBuf,NsList,NsTC} = decode_rr_section(Opcode,NsBuf,NsCount,Buffer),
- {Rest,ArList,ArTC} = decode_rr_section(Opcode,ArBuf,ArCount,Buffer),
+ QdBuf/binary>>=Buffer, Mdns) ->
+ {AnBuf,QdList,QdTC} = decode_query_section(QdBuf,QdCount,Buffer,Mdns),
+ {NsBuf,AnList,AnTC} =
+ decode_rr_section(AnBuf,AnCount,Buffer,{Opcode,Mdns}),
+ {ArBuf,NsList,NsTC} =
+ decode_rr_section(NsBuf,NsCount,Buffer,{Opcode,Mdns}),
+ {Rest,ArList,ArTC} =
+ decode_rr_section(ArBuf,ArCount,Buffer,{Opcode,Mdns}),
?MATCH_ELSE_DECODE_ERROR(
Rest,
<<>>,
@@ -197,40 +202,40 @@ do_decode(<<Id:16,
arlist=ArList}
end)
end);
-do_decode(_) ->
+do_decode(_, _) ->
%% DNS message does not even match header
throw(?DECODE_ERROR).
-decode_query_section(Bin, N, Buffer) ->
- decode_query_section(Bin, N, Buffer, []).
+decode_query_section(Bin, N, Buffer, Mdns) ->
+ decode_query_section(Bin, N, Buffer, Mdns, []).
-decode_query_section(<<>>=Rest, N, _Buffer, Qs) ->
+decode_query_section(<<>>=Rest, N, _Buffer, _Mdns, Qs) ->
{Rest,reverse(Qs),N =/= 0};
-decode_query_section(Rest, 0, _Buffer, Qs) ->
+decode_query_section(Rest, 0, _Buffer, _Mdns, Qs) ->
{Rest,reverse(Qs),false};
-decode_query_section(Bin, N, Buffer, Qs) ->
+decode_query_section(Bin, N, Buffer, Mdns, Qs) ->
?MATCH_ELSE_DECODE_ERROR(
decode_name(Bin, Buffer),
{<<T:16,C:16,Rest/binary>>,Name},
begin
- {Class,UnicastResponse} = decode_class(C),
+ {Class,UnicastResponse} = decode_class(C, Mdns),
DnsQuery =
#dns_query{
domain = Name,
type = decode_type(T),
class = Class,
unicast_response = UnicastResponse},
- decode_query_section(Rest, N-1, Buffer, [DnsQuery|Qs])
+ decode_query_section(Rest, N-1, Buffer, Mdns, [DnsQuery|Qs])
end).
-decode_rr_section(Opcode, Bin, N, Buffer) ->
- decode_rr_section(Opcode, Bin, N, Buffer, []).
-
-decode_rr_section(_Opcode, <<>>=Rest, N, _Buffer, RRs) ->
+decode_rr_section(Bin, N, Buffer, Opts) ->
+ decode_rr_section(Bin, N, Buffer, Opts, []).
+%%
+decode_rr_section(<<>>=Rest, N, _Buffer, _Opts, RRs) ->
{Rest,reverse(RRs),N =/= 0};
-decode_rr_section(_Opcode, Rest, 0, _Buffer, RRs) ->
+decode_rr_section(Rest, 0, _Buffer, _Opts, RRs) ->
{Rest,reverse(RRs),false};
-decode_rr_section(Opcode, Bin, N, Buffer, RRs) ->
+decode_rr_section(Bin, N, Buffer, {Opcode,Mdns} = Opts, RRs) ->
?MATCH_ELSE_DECODE_ERROR(
decode_name(Bin, Buffer),
{<<T:16/unsigned,C:16/unsigned,TTL:4/binary,
@@ -278,14 +283,8 @@ decode_rr_section(Opcode, Bin, N, Buffer, RRs) ->
error = Error,
other_data = OtherData});
_ ->
- {Class,CacheFlush} = decode_class(C),
- Data = if
- %% RFC 2136: 2.4. Allow length zero data for UPDATE
- Opcode == ?UPDATE, D == <<>> ->
- #dns_rr{}#dns_rr.data;
- true ->
- decode_data(D, Class, Type, Buffer)
- end,
+ {Class,CacheFlush} = decode_class(C, Mdns),
+ Data = decode_data(D, Class, Type, Buffer, Opcode),
<<TimeToLive:32/signed>> = TTL,
#dns_rr{
domain = Name,
@@ -295,25 +294,31 @@ decode_rr_section(Opcode, Bin, N, Buffer, RRs) ->
data = Data,
func = CacheFlush}
end,
- decode_rr_section(Opcode, Rest, N-1, Buffer, [RR|RRs])
+ decode_rr_section(Rest, N-1, Buffer, Opts, [RR|RRs])
end).
%%
%% Encode a user query
%%
-encode(Q) ->
- QdCount = length(Q#dns_rec.qdlist),
- AnCount = length(Q#dns_rec.anlist),
- NsCount = length(Q#dns_rec.nslist),
- ArCount = length(Q#dns_rec.arlist),
- OC = Q#dns_rec.header#dns_header.opcode,
- B0 = encode_header(Q#dns_rec.header, QdCount, AnCount, NsCount, ArCount),
+encode(Q) -> encode(Q, true). % Backwards compatible
+%%
+encode(
+ #dns_rec{
+ header = Header,
+ qdlist = QdList, anlist = AnList, nslist = NsList, arlist = ArList },
+ Mdns)
+ when is_boolean(Mdns) ->
+ B0 =
+ encode_header(
+ Header,
+ length(QdList), length(AnList), length(NsList), length(ArList)),
+ Opcode = Header#dns_header.opcode,
C0 = gb_trees:empty(),
- {B1,C1} = encode_query_section(B0, C0, Q#dns_rec.qdlist),
- {B2,C2} = encode_res_section(OC, B1, C1, Q#dns_rec.anlist),
- {B3,C3} = encode_res_section(OC, B2, C2, Q#dns_rec.nslist),
- {B,_} = encode_res_section(OC, B3, C3, Q#dns_rec.arlist),
+ {B1,C1} = encode_query_section(B0, Mdns, C0, QdList),
+ {B2,C2} = encode_res_section(B1, {Opcode,Mdns}, C1, AnList),
+ {B3,C3} = encode_res_section(B2, {Opcode,Mdns}, C2, NsList),
+ {B,_} = encode_res_section(B3, {Opcode,Mdns}, C3, ArList),
B.
@@ -335,19 +340,20 @@ encode_header(#dns_header{id=Id}=H, QdCount, AnCount, NsCount, ArCount) ->
%% RFC 1035: 4.1.2. Question section format
%%
-encode_query_section(Bin, Comp, []) -> {Bin,Comp};
-encode_query_section(Bin0, Comp0, [#dns_query{domain=DName}=Q | Qs]) ->
+encode_query_section(Bin, _Mdns, Comp, []) -> {Bin,Comp};
+encode_query_section(Bin0, Mdns, Comp0, [#dns_query{domain=DName}=Q | Qs]) ->
T = encode_type(Q#dns_query.type),
- C = encode_class(Q#dns_query.class, Q#dns_query.unicast_response),
+ C = encode_class(
+ Q#dns_query.class, Mdns andalso Q#dns_query.unicast_response),
{Bin,Comp} = encode_name(Bin0, Comp0, byte_size(Bin0), DName),
- encode_query_section(<<Bin/binary,T:16,C:16>>, Comp, Qs).
+ encode_query_section(<<Bin/binary,T:16,C:16>>, Mdns, Comp, Qs).
%% RFC 1035: 4.1.3. Resource record format
%% RFC 6891: 6.1.2, 6.1.3, 6.2.3 Opt RR format
%%
-encode_res_section(_Opcode, Bin, Comp, []) -> {Bin,Comp};
+encode_res_section(Bin, _Opts, Comp, []) -> {Bin,Comp};
encode_res_section(
- Opcode, Bin, Comp,
+ Bin, Opts, Comp,
[#dns_rr{
domain = DName,
type = Type,
@@ -356,10 +362,10 @@ encode_res_section(
ttl = TTL,
data = Data} | Rs]) ->
encode_res_section_rr(
- Opcode, Bin, Comp, Rs, DName, Type, Class, CacheFlush,
+ Bin, Opts, Comp, Rs, DName, Type, Class, CacheFlush,
<<TTL:32/signed>>, Data);
encode_res_section(
- Opcode, Bin, Comp,
+ Bin, Opts, Comp,
[#dns_rr_opt{
domain = DName,
udp_payload_size = UdpPayloadSize,
@@ -370,10 +376,10 @@ encode_res_section(
do = DnssecOk} | Rs]) ->
DO = case DnssecOk of true -> 1; false -> 0 end,
encode_res_section_rr(
- Opcode, Bin, Comp, Rs, DName, ?S_OPT, UdpPayloadSize, false,
+ Bin, Opts, Comp, Rs, DName, ?S_OPT, UdpPayloadSize, false,
<<ExtRCode,Version,DO:1,Z:15>>, Data);
encode_res_section(
- Opcode, Bin, Comp,
+ Bin, Opts, Comp,
[#dns_rr_tsig{
domain = DName,
algname = AlgName,
@@ -385,26 +391,21 @@ encode_res_section(
other_data = OtherData}]) ->
Data = {AlgName,Now,Fudge,MAC,OriginalId,Error,OtherData},
encode_res_section_rr(
- Opcode, Bin, Comp, [], DName, ?S_TSIG, ?S_ANY, false,
+ Bin, Opts, Comp, [], DName, ?S_TSIG, ?S_ANY, false,
<<0:32/signed>>, Data).
encode_res_section_rr(
- Opcode, Bin0, Comp0, Rs, DName, Type, Class, CacheFlush, TTL, Data) ->
+ Bin0, {Opcode,Mdns} = Opts, Comp0, Rs,
+ DName, Type, Class, CacheFlush, TTL, Data) ->
T = encode_type(Type),
- C = encode_class(Class, CacheFlush),
+ C = encode_class(Class, Mdns and CacheFlush),
{Bin,Comp1} = encode_name(Bin0, Comp0, byte_size(Bin0), DName),
Pos = byte_size(Bin)+(2+2)+byte_size(TTL)+2,
- {DataBin,Comp} = if
- Opcode == update, Data == #dns_rr{}#dns_rr.data ->
- {<<>>,Comp1};
- true ->
- encode_data(Comp1, Pos, Type, Class, Data)
- end,
+ {DataBin,Comp} = encode_data(Comp1, Pos, Type, Class, Data, Opcode),
DataSize = byte_size(DataBin),
encode_res_section(
- Opcode,
<<Bin/binary,T:16,C:16,TTL/binary,DataSize:16,DataBin/binary>>,
- Comp, Rs).
+ Opts, Comp, Rs).
%%
%% Resource types
@@ -497,21 +498,25 @@ encode_type(Type) ->
%% Resource classes
%%
-decode_class(C0) ->
+decode_class(C, false) ->
+ {decode_class(C),false};
+decode_class(C0, true) ->
FlagBit = 16#8000,
C = C0 band (bnot FlagBit),
- Class =
- case C of
- ?C_IN -> in;
- ?C_CHAOS -> chaos;
- ?C_HS -> hs;
- ?C_NONE -> none;
- ?C_ANY -> any;
- _ -> C %% raw unknown class
- end,
+ Class = decode_class(C),
Flag = (C0 band FlagBit) =/= 0,
{Class,Flag}.
+decode_class(C) ->
+ case C of
+ ?C_IN -> in;
+ ?C_CHAOS -> chaos;
+ ?C_HS -> hs;
+ ?C_NONE -> none;
+ ?C_ANY -> any;
+ _ -> C %% raw unknown class
+ end.
+
encode_class(Class, Flag) ->
C = encode_class(Class),
@@ -558,7 +563,14 @@ encode_boolean(B) when is_integer(B) -> B.
decode_boolean(0) -> false;
decode_boolean(I) when is_integer(I) -> true.
-
+decode_data(Data, Class, Type, Buffer, Opcode) ->
+ if
+ %% RFC 2136: 2.4. Allow length zero data for UPDATE
+ Opcode == ?UPDATE, Data == <<>> ->
+ #dns_rr{}#dns_rr.data;
+ true ->
+ decode_data(Data, Class, Type, Buffer)
+ end.
%%
%% Data field -> term() content representation
%%
@@ -771,6 +783,13 @@ decode_name_label(Label, Name, N) ->
erlang:error(badarg, [Label,Name,N])
end.
+encode_data(Comp, Pos, Type, Class, Data, Opcode) ->
+ if
+ Opcode == update, Data == #dns_rr{}#dns_rr.data ->
+ {<<>>,Comp};
+ true ->
+ encode_data(Comp, Pos, Type, Class, Data)
+ end.
%%
%% Data field -> {binary(),NewCompressionTable}
%%
diff --git a/lib/kernel/src/inet_dns_record_adts.pl b/lib/kernel/src/inet_dns_record_adts.pl
index f3331222fc..0adc2285b9 100644
--- a/lib/kernel/src/inet_dns_record_adts.pl
+++ b/lib/kernel/src/inet_dns_record_adts.pl
@@ -24,16 +24,18 @@ use strict;
# for internal records.
#
# The following defines which ADT function sets that will be generated
-# and which record fields that will be exponated.
+# and which record fields that will be exposed.
#
# (FunctionBaseName => [RecordName, FieldName ...], ...)
my %Names = ('msg' => ['dns_rec', 'header', 'qdlist',
'anlist', 'nslist', 'arlist'],
- 'dns_rr' => ['dns_rr', 'domain', 'type', 'class', 'ttl', 'data'],
+ 'dns_rr' => ['dns_rr', 'domain', 'type', 'class', 'ttl', 'data',
+ 'func'],
'dns_rr_opt' => ['dns_rr_opt', 'domain', 'type',
'udp_payload_size', 'ext_rcode', 'version',
'z', 'data', 'do'],
- 'dns_query' => ['dns_query', 'domain', 'type', 'class'],
+ 'dns_query' => ['dns_query', 'domain', 'type', 'class',
+ 'unicast_response'],
'header' => ['dns_header', 'id', 'qr', 'opcode', 'aa', 'tc',
'rd', 'ra', 'pr', 'rcode']);
# The functions are defined in the __DATA__ section at the end.
diff --git a/lib/kernel/src/inet_res.erl b/lib/kernel/src/inet_res.erl
index 091ebef91c..c2b5b3be77 100644
--- a/lib/kernel/src/inet_res.erl
+++ b/lib/kernel/src/inet_res.erl
@@ -691,7 +691,7 @@ make_query(Dname, Class, Type, Options, Edns) ->
class=Class}],
arlist=ARList},
?verbose(Options#options.verbose, "Query: ~p~n", [dns_msg(Msg)]),
- Buffer = inet_dns:encode(Msg),
+ Buffer = inet_dns:encode(Msg, false),
{Msg, Buffer}.
%% --------------------------------------------------------------------------
@@ -1091,7 +1091,7 @@ query_tcp(Timeout, Msg, Buffer, IP, Port, Verbose) ->
end.
decode_answer(Answer, Q_Msg, Verbose) ->
- case inet_dns:decode(Answer) of
+ case inet_dns:decode(Answer, false) of
{ok, #dns_rec{header = H, arlist = ARList} = Msg} ->
?verbose(Verbose, "Got reply: ~p~n", [dns_msg(Msg)]),
T = case lists:keyfind(dns_rr_tsig, 1, ARList) of
diff --git a/lib/kernel/test/inet_res_SUITE.erl b/lib/kernel/test/inet_res_SUITE.erl
index 045fdcc83b..3a0f2bd05a 100644
--- a/lib/kernel/test/inet_res_SUITE.erl
+++ b/lib/kernel/test/inet_res_SUITE.erl
@@ -35,7 +35,8 @@
edns0/1, edns0_multi_formerr/1, txt_record/1, files_monitor/1,
nxdomain_reply/1, last_ms_answer/1, intermediate_error/1,
servfail_retry_timeout_default/1, servfail_retry_timeout_1000/1,
- label_compression_limit/1, update/1, tsig_client/1, tsig_server/1
+ label_compression_limit/1, update/1, tsig_client/1, tsig_server/1,
+ mdns_encode_decode/1
]).
-export([
gethostbyaddr/0, gethostbyaddr/1,
@@ -78,6 +79,7 @@ all() ->
intermediate_error,
servfail_retry_timeout_default, servfail_retry_timeout_1000,
label_compression_limit, update, tsig_client, tsig_server,
+ mdns_encode_decode,
gethostbyaddr, gethostbyaddr_v6, gethostbyname,
gethostbyname_v6, getaddr, getaddr_v6, ipv4_to_ipv6,
host_and_addr].
@@ -1661,6 +1663,83 @@ tsig_server(Domain, TS0, Sock) ->
ok = gen_tcp:send(Sock, PktR3S).
+%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% inet_dns encode/decode specials
+%% Should maybe be a suite of its own.
+
+mdns_encode_decode(Config) when is_list(Config) ->
+ Id = 4711,
+ Opcode = 'query',
+ Class = in,
+ Type = txt,
+ Domain = "test.local",
+ Text = ["abc", "123"],
+ BinText = <<3,$a,$b,$c, 3,$1,$2,$3>>, % Wire format for Text
+ IN_h = 32769, % Class IN with high bit set
+ %%
+ %% Create a unicast-response to a mDNS query
+ %% with cache-flush bit on the RR record (func field),
+ %% which sets the class fields high bit when encoded
+ Header =
+ inet_dns:make_header(
+ [{id, Id}, {qr, true}, {opcode, Opcode},
+ {aa, false}, {tc, false}, {rd, false}, {ra, false}, {pr, false}]),
+ Query =
+ inet_dns:make_dns_query(
+ [{class, Class}, {type, Type}, {domain, Domain},
+ {unicast_response, true}]), % High bit 1
+ TxtRR =
+ inet_dns:make_rr(
+ [{domain, Domain}, {class, Class}, {type, Type},
+ {data, Text},
+ {func, true}]), % High bit 1
+ Msg =
+ inet_dns:make_msg(
+ [{header, Header}, {qdlist, [Query]}, {anlist, [TxtRR]}]),
+ %%
+ %% Encode and verify decode
+ Buffer = inet_dns:encode(Msg),
+ {{ok, Msg}, Msg} = {inet_dns:decode(Buffer), Msg},
+ %%
+ %% Decode as if not mDNS, which exposes the high class field bit,
+ %% and doesn't decode the RR data
+ Query2 =
+ inet_dns:make_dns_query(
+ Query,
+ [{class,IN_h},
+ {unicast_response,false}]), % High bit 0
+ TxtRR2 =
+ inet_dns:make_rr(
+ TxtRR,
+ [{class,IN_h},
+ {data,BinText}, % Raw, encoded
+ {func,false}]), % High bit 0
+ Msg2 = inet_dns:make_msg(Msg, [{qdlist, [Query2]}, {anlist, [TxtRR2]}]),
+ {{ok, Msg2}, Msg2} = {inet_dns:decode(Buffer, false), Msg2},
+ %%
+ %% Encode non-mDNS which ignores the high class bit flags
+ %% in #dns_query.unicast_response and #dns_rr.func
+ Buffer3 = inet_dns:encode(Msg, false),
+ %%
+ %% Decode non-mDNS and verify
+ Query3 =
+ inet_dns:make_dns_query(Query, unicast_response, false), % High bit 0
+ TxtRR3 = inet_dns:make_rr(TxtRR, func, false), % High bit 0
+ Msg3 = inet_dns:make_msg(Msg, [{qdlist, [Query3]}, {anlist, [TxtRR3]}]),
+ {{ok, Msg3}, Msg3} = {inet_dns:decode(Buffer3, false), Msg3},
+ %%
+ %% Decode mDNS should give the same answer since the high bits
+ %% in the class fields are encoded as zero
+ {{ok, Msg3}, Msg3} = {inet_dns:decode(Buffer3, true), Msg3},
+ %%
+ %% Encode non-mDNS with class >= 32768
+ Buffer4 = inet_dns:encode(Msg2, false),
+ {{ok, Msg2}, Msg2} = {inet_dns:decode(Buffer4, false), Msg2},
+ %%
+ %% Decoding for mDNS should set the high class field flags
+ {{ok, Msg}, Msg} = {inet_dns:decode(Buffer4, true), Msg},
+ ok.
+
%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Compatibility tests. Call the inet_SUITE tests, but with
%% lookup = [file,dns] instead of [native]
--
2.35.3
