diff options
Diffstat (limited to 'lib/kernel/src/inet_res.erl')
| -rw-r--r-- | lib/kernel/src/inet_res.erl | 330 |
1 files changed, 202 insertions, 128 deletions
diff --git a/lib/kernel/src/inet_res.erl b/lib/kernel/src/inet_res.erl index 4e71944492..4e7809564c 100644 --- a/lib/kernel/src/inet_res.erl +++ b/lib/kernel/src/inet_res.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1997-2021. All Rights Reserved. +%% Copyright Ericsson AB 1997-2022. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. @@ -71,7 +71,7 @@ -type dns_name() :: string(). --type rr_type() :: a | aaaa | caa | cname | gid | hinfo | ns | mb | md | mg +-type dns_rr_type() :: a | aaaa | caa | cname | gid | hinfo | ns | mb | md | mg | mf | minfo | mx | naptr | null | ptr | soa | spf | srv | txt | uid | uinfo | unspec | uri | wks. @@ -109,7 +109,7 @@ -spec resolve(Name, Class, Type) -> {ok, dns_msg()} | Error when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Error :: {error, Reason} | {error,{Reason,dns_msg()}}, Reason :: inet:posix() | res_error(). @@ -120,7 +120,7 @@ resolve(Name, Class, Type) -> {ok, dns_msg()} | Error when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Opts :: [Opt], Opt :: res_option() | verbose | atom(), Error :: {error, Reason} | {error,{Reason,dns_msg()}}, @@ -133,7 +133,7 @@ resolve(Name, Class, Type, Opts) -> {ok, dns_msg()} | Error when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Opts :: [Opt], Opt :: res_option() | verbose | atom(), Timeout :: timeout(), @@ -147,7 +147,7 @@ resolve(Name, Class, Type, Opts, Timeout) -> Res = res_query(Nm, Class, Type, Opts, Timer), _ = inet:stop_timer(Timer), Res; - Error -> + {error, _} = Error -> Error end. @@ -160,7 +160,7 @@ resolve(Name, Class, Type, Opts, Timeout) -> -spec lookup(Name, Class, Type) -> [dns_data()] when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(). + Type :: dns_rr_type(). lookup(Name, Class, Type) -> lookup(Name, Class, Type, []). @@ -168,7 +168,7 @@ lookup(Name, Class, Type) -> -spec lookup(Name, Class, Type, Opts) -> [dns_data()] when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Opts :: [res_option() | verbose]. lookup(Name, Class, Type, Opts) -> @@ -177,7 +177,7 @@ lookup(Name, Class, Type, Opts) -> -spec lookup(Name, Class, Type, Opts, Timeout) -> [dns_data()] when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Opts :: [res_option() | verbose], Timeout :: timeout(). @@ -203,7 +203,7 @@ lookup_filter({error,_}, _, _) -> []. -spec nslookup(Name, Class, Type) -> {ok, dns_msg()} | {error, Reason} when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Reason :: inet:posix() | res_error(). nslookup(Name, Class, Type) -> @@ -213,14 +213,14 @@ nslookup(Name, Class, Type) -> {ok, dns_msg()} | {error, Reason} when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Timeout :: timeout(), Reason :: inet:posix() | res_error(); (Name, Class, Type, Nameservers) -> {ok, dns_msg()} | {error, Reason} when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Nameservers :: [nameserver()], Reason :: inet:posix() | res_error(). @@ -233,7 +233,7 @@ nslookup(Name, Class, Type, NSs) -> % For backwards compatibility {ok, dns_msg()} | {error, Reason} when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Nameservers :: [nameserver()], Reason :: inet:posix(). @@ -244,7 +244,7 @@ nnslookup(Name, Class, Type, NSs) -> {ok, dns_msg()} | {error, Reason} when Name :: dns_name() | inet:ip_address(), Class :: dns_class(), - Type :: rr_type(), + Type :: dns_rr_type(), Timeout :: timeout(), Nameservers :: [nameserver()], Reason :: inet:posix(). @@ -355,40 +355,42 @@ gethostbyaddr(IP,Timeout) -> _ = inet:stop_timer(Timer), Res. -gethostbyaddr_tm({A,B,C,D} = IP, Timer) when ?ip(A,B,C,D) -> - inet_db:res_update_conf(), - case inet_db:gethostbyaddr(IP) of - {ok, HEnt} -> {ok, HEnt}; - _ -> res_gethostbyaddr(dn_in_addr_arpa(A,B,C,D), IP, Timer) - end; -gethostbyaddr_tm({A,B,C,D,E,F,G,H} = IP, Timer) when ?ip6(A,B,C,D,E,F,G,H) -> - inet_db:res_update_conf(), - case inet_db:gethostbyaddr(IP) of - {ok, HEnt} -> {ok, HEnt}; - _ -> res_gethostbyaddr(dn_ip6_int(A,B,C,D,E,F,G,H), IP, Timer) - end; -gethostbyaddr_tm(Addr,Timer) when is_list(Addr) -> +gethostbyaddr_tm(Addr, Timer) when is_atom(Addr) -> + gethostbyaddr_tm(atom_to_list(Addr), Timer); +gethostbyaddr_tm(Addr, Timer) when is_list(Addr) -> case inet_parse:address(Addr) of - {ok, IP} -> gethostbyaddr_tm(IP,Timer); + {ok, IP} -> gethostbyaddr_tm(IP, Timer); _Error -> {error, formerr} end; -gethostbyaddr_tm(Addr,Timer) when is_atom(Addr) -> - gethostbyaddr_tm(atom_to_list(Addr),Timer); -gethostbyaddr_tm(_,_) -> {error, formerr}. - -%% -%% Send the gethostbyaddr query to: -%% 1. the list of normal names servers -%% 2. the list of alternative name servers -%% -res_gethostbyaddr(Addr, IP, Timer) -> - case res_query(Addr, in, ptr, [], Timer) of - {ok, Rec} -> - inet_db:res_gethostbyaddr(IP, Rec); - {error,{qfmterror,_}} -> {error,einval}; - {error,{Reason,_}} -> {error,Reason}; - Error -> - Error +gethostbyaddr_tm(IP, Timer) -> + %% The call to norm_ip/1 here translates a lookup of + %% ::ffff:A.B.C.D (AAAA in ...ip6.arpa) into a plain + %% A.B.C.D (A in ...in-addr.arpa) lookup, and pretends + %% the result as if it was from the original IPv6 lookup + %% + case dn_ip(norm_ip(IP)) of + {error, _} = Error -> + Error; + {ok, Name} -> + %% Try cached first + inet_db:res_update_conf(), + case inet_db:gethostbyaddr(Name, IP) of + {ok, _HEnt} = Result -> + Result; + {error, nxdomain} -> + %% Do a resolver lookup + case res_query(Name, in, ?S_PTR, [], Timer) of + {ok, Rec} -> + %% Process and cache DNS Record + inet_db:res_gethostbyaddr(Name, IP, Rec); + {error,{qfmterror,_}} -> + {error,einval}; + {error,{Reason,_}} -> + {error,Reason}; + Error -> + Error + end + end end. %% -------------------------------------------------------------------------- @@ -453,10 +455,20 @@ gethostbyname_tm(_Name, _Family, _Timer) -> %% Caches the answer. %% -------------------------------------------------------------------------- +%% Duplicate of inet.hrl: #hostent{}, but with DNS RR types in h_addrtype +%% and dns_data() in h_addr_list. +-type hostent() :: + {'hostent', + H_name :: inet:hostname(), + H_aliases :: [inet:hostname()], + H_addrtype :: dns_rr_type(), + H_length :: non_neg_integer(), + H_addr_list :: [dns_data()]}. + -spec getbyname(Name, Type) -> {ok, Hostent} | {error, Reason} when Name :: dns_name(), - Type :: rr_type(), - Hostent :: inet:hostent(), + Type :: dns_rr_type(), + Hostent :: inet:hostent() | hostent(), Reason :: inet:posix() | res_error(). getbyname(Name, Type) -> @@ -464,9 +476,9 @@ getbyname(Name, Type) -> -spec getbyname(Name, Type, Timeout) -> {ok, Hostent} | {error, Reason} when Name :: dns_name(), - Type :: rr_type(), + Type :: dns_rr_type(), Timeout :: timeout(), - Hostent :: inet:hostent(), + Hostent :: inet:hostent() | hostent(), Reason :: inet:posix() | res_error(). getbyname(Name, Type, Timeout) -> @@ -479,12 +491,17 @@ getbyname_tm(Name, Type, Timer) when is_list(Name) -> case type_p(Type) of true -> case inet_parse:visible_string(Name) of - false -> {error, formerr}; + false -> + {error, formerr}; true -> + %% Try cached first inet_db:res_update_conf(), case inet_db:getbyname(Name, Type) of - {ok, HEnt} -> {ok, HEnt}; - _ -> res_getbyname(Name, Type, Timer) + {ok, HEnt} -> + {ok, HEnt}; + _ -> + %% Do a resolver lookup + res_getbyname(Name, Type, Timer) end end; false -> @@ -577,6 +594,7 @@ res_getby_search(_Name, [], Reason,_,_) -> res_getby_query(Name, Type, Timer) -> case res_query(Name, in, Type, [], Timer) of {ok, Rec} -> + %% Process and cache DNS Record inet_db:res_hostent_by_domain(Name, Type, Rec); {error,{qfmterror,_}} -> {error,einval}; {error,{Reason,_}} -> {error,Reason}; @@ -586,6 +604,7 @@ res_getby_query(Name, Type, Timer) -> res_getby_query(Name, Type, Timer, NSs) -> case res_query(Name, in, Type, [], Timer, NSs) of {ok, Rec} -> + %% Process and cache DNS Record inet_db:res_hostent_by_domain(Name, Type, Rec); {error,{qfmterror,_}} -> {error,einval}; {error,{Reason,_}} -> {error,Reason}; @@ -649,6 +668,7 @@ make_query(Dname, Class, Type, Opts) -> make_query(Dname, Class, Type, Options, Edns) -> Id = inet_db:res_option(next_id), Recurse = Options#options.recurse, + RD = Recurse =:= 1 orelse Recurse =:= true, % (0 | 1 | true | false) ARList = case Edns of false -> []; _ -> @@ -656,17 +676,18 @@ make_query(Dname, Class, Type, Options, Edns) -> [#dns_rr_opt{udp_payload_size=PSz, version=Edns}] end, - Msg = #dns_rec{header=#dns_header{id=Id, + Msg = #dns_rec{header=#dns_header{id=Id, + qr=false, opcode='query', - rd=Recurse, + rd=RD, rcode=?NOERROR}, - qdlist=[#dns_query{domain=Dname, - type=Type, - class=Class}], + qdlist=[#dns_query{domain=Dname, + type=Type, + class=Class}], arlist=ARList}, ?verbose(Options#options.verbose, "Query: ~p~n", [dns_msg(Msg)]), Buffer = inet_dns:encode(Msg), - {Id, Buffer}. + {Msg, Buffer}. %% -------------------------------------------------------------------------- %% socket helpers @@ -727,7 +748,7 @@ do_udp_recv(I, IP, Port, Timeout, Decode, Time, PollCnt) -> {ok,Reply} -> case Decode(Reply) of false when Timeout =:= 0 -> - %% This is a compromize between the hard way i.e + %% This is a compromise between the hard way i.e %% in the clause below if Timeout becomes 0 bailout %% immediately and risk that the right reply lies %% ahead after some bad id replies, and the @@ -820,13 +841,13 @@ query_nss_edns( #q{options = #options{ udp_payload_size = PSz}=Options, - edns = {Id,Buffer}}=Q, + edns = EDNSQuery}=Q, [NsSpec|NSs], Timer, Retry, I, S_0, Reason, RetryNSs) -> %% {IP,Port} = NS = servfail_retry_wait(NsSpec), {S,Result} = query_ns( - S_0, Id, Buffer, IP, Port, Timer, Retry, I, Options, PSz), + S_0, EDNSQuery, IP, Port, Timer, Retry, I, Options, PSz), case Result of {error,{E,_}} when E =:= qfmterror; @@ -848,19 +869,21 @@ query_nss_edns( end. query_nss_dns( - #q{dns = Qdns}=Q_0, + #q{dns = DNSQuery_0}=Q_0, [NsSpec|NSs], Timer, Retry, I, S_0, Reason, RetryNSs) -> %% {IP,Port} = NS = servfail_retry_wait(NsSpec), #q{options = Options, - dns = {Id,Buffer}}=Q = + dns = DNSQuery}=Q = if - is_function(Qdns, 0) -> Q_0#q{dns=Qdns()}; - true -> Q_0 + is_function(DNSQuery_0, 0) -> + Q_0#q{dns=DNSQuery_0()}; + true -> + Q_0 end, {S,Result} = query_ns( - S_0, Id, Buffer, IP, Port, Timer, Retry, I, Options, ?PACKETSZ), + S_0, DNSQuery, IP, Port, Timer, Retry, I, Options, ?PACKETSZ), query_nss_result( Q, NSs, Timer, Retry, I, S, Reason, RetryNSs, NS, Result). @@ -952,14 +975,14 @@ query_retries_error(#q{options=#options{nxdomain_reply=NxReply}}, S, Reason) -> end. -query_ns(S0, Id, Buffer, IP, Port, Timer, Retry, I, +query_ns(S0, {Msg, Buffer}, IP, Port, Timer, Retry, I, #options{timeout=Tm,usevc=UseVC,verbose=Verbose}, PSz) -> case UseVC orelse iolist_size(Buffer) > PSz of true -> TcpTimeout = inet:timeout(Tm*5, Timer), {S0, - query_tcp(TcpTimeout, Id, Buffer, IP, Port, Verbose)}; + query_tcp(TcpTimeout, Msg, Buffer, IP, Port, Verbose)}; false -> case udp_open(S0, IP) of {ok,S} -> @@ -967,13 +990,13 @@ query_ns(S0, Id, Buffer, IP, Port, Timer, Retry, I, inet:timeout( (Tm * (1 bsl I)) div Retry, Timer), case query_udp( - S, Id, Buffer, IP, Port, UdpTimeout, Verbose) + S, Msg, Buffer, IP, Port, UdpTimeout, Verbose) of {ok,#dns_rec{header=H}} when H#dns_header.tc -> TcpTimeout = inet:timeout(Tm*5, Timer), {S, query_tcp( - TcpTimeout, Id, Buffer, IP, Port, Verbose)}; + TcpTimeout, Msg, Buffer, IP, Port, Verbose)}; {error, econnrefused} = Err -> ok = udp_close(S), {#sock{}, Err}; @@ -984,9 +1007,9 @@ query_ns(S0, Id, Buffer, IP, Port, Timer, Retry, I, end end. -query_udp(_S, _Id, _Buffer, _IP, _Port, 0, _Verbose) -> +query_udp(_S, _Msg, _Buffer, _IP, _Port, 0, _Verbose) -> timeout; -query_udp(S, Id, Buffer, IP, Port, Timeout, Verbose) -> +query_udp(S, Msg, Buffer, IP, Port, Timeout, Verbose) -> ?verbose(Verbose, "Try UDP server : ~p:~p (timeout=~w)\n", [IP,Port,Timeout]), case @@ -999,7 +1022,7 @@ query_udp(S, Id, Buffer, IP, Port, Timeout, Verbose) -> Decode = fun ({RecIP,RecPort,Answer}) when RecIP =:= IP, RecPort =:= Port -> - case decode_answer(Answer, Id, Verbose) of + case decode_answer(Answer, Msg, Verbose) of {error,badid} -> false; Reply -> @@ -1020,9 +1043,9 @@ query_udp(S, Id, Buffer, IP, Port, Timeout, Verbose) -> {error,econnrefused} end. -query_tcp(0, _Id, _Buffer, _IP, _Port, _Verbose) -> +query_tcp(0, _Msg, _Buffer, _IP, _Port, _Verbose) -> timeout; -query_tcp(Timeout, Id, Buffer, IP, Port, Verbose) -> +query_tcp(Timeout, Msg, Buffer, IP, Port, Verbose) -> ?verbose(Verbose, "Try TCP server : ~p:~p (timeout=~w)\n", [IP, Port, Timeout]), Family = case IP of @@ -1038,7 +1061,7 @@ query_tcp(Timeout, Id, Buffer, IP, Port, Verbose) -> case gen_tcp:recv(S, 0, Timeout) of {ok, Answer} -> gen_tcp:close(S), - case decode_answer(Answer, Id, Verbose) of + case decode_answer(Answer, Msg, Verbose) of {ok, _} = OK -> OK; {error, badid} -> {error, servfail}; Error -> Error @@ -1062,96 +1085,147 @@ query_tcp(Timeout, Id, Buffer, IP, Port, Verbose) -> _:_ -> {error, einval} end. -decode_answer(Answer, Id, Verbose) -> +decode_answer(Answer, Q_Msg, Verbose) -> case inet_dns:decode(Answer) of - {ok, Msg} -> + {ok, #dns_rec{header = H, arlist = ARList} = Msg} -> ?verbose(Verbose, "Got reply: ~p~n", [dns_msg(Msg)]), - E = case lists:keyfind(dns_rr_opt, 1, Msg#dns_rec.arlist) of + E = case lists:keyfind(dns_rr_opt, 1, ARList) of false -> 0; #dns_rr_opt{ext_rcode=ExtRCode} -> ExtRCode end, - H = Msg#dns_rec.header, RCode = (E bsl 4) bor H#dns_header.rcode, case RCode of - ?NOERROR -> - if H#dns_header.id =/= Id -> - {error,badid}; - length(Msg#dns_rec.qdlist) =/= 1 -> - {error,{noquery,Msg}}; - true -> - {ok, Msg} - end; + ?NOERROR -> decode_answer_noerror(Q_Msg, Msg, H); ?FORMERR -> {error,{qfmterror,Msg}}; ?SERVFAIL -> {error,{servfail,Msg}}; ?NXDOMAIN -> {error,{nxdomain,Msg}}; ?NOTIMP -> {error,{notimp,Msg}}; ?REFUSED -> {error,{refused,Msg}}; ?BADVERS -> {error,{badvers,Msg}}; - _ -> {error,{unknown,Msg}} + _ -> {error,{unknown,Msg}} end; {error, formerr} = Error -> ?verbose(Verbose, "Got reply: decode format error~n", []), Error end. +decode_answer_noerror( + #dns_rec{header = Q_H, qdlist = [Q_RR]}, + #dns_rec{qdlist = QDList} = Msg, + H) -> + %% Validate the reply + if + H#dns_header.id =/= Q_H#dns_header.id -> + {error,badid}; + H#dns_header.qr =/= true; + H#dns_header.opcode =/= Q_H#dns_header.opcode; + H#dns_header.rd =/= Q_H#dns_header.rd -> + {error,{unknown,Msg}}; + true -> + case QDList of + [RR] -> + case + (RR#dns_query.class =:= Q_RR#dns_query.class) + andalso + (RR#dns_query.type =:= Q_RR#dns_query.type) + andalso + inet_db:eq_domains( + RR#dns_query.domain, Q_RR#dns_query.domain) + of + true -> + {ok, Msg}; + false -> + {error,{noquery,Msg}} + end; + _ when is_list(QDList) -> + {error,{noquery,Msg}} + end + end. + %% %% Transform domain name or address %% 1. "a.b.c" => %% "a.b.c" %% 2. "1.2.3.4" => -%% "4.3.2.1.IN-ADDR.ARPA" +%% "4.3.2.1.in-addr.arpa" %% 3. "4321:0:1:2:3:4:567:89ab" => -%% "b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.1.2.3.4.IP6.ARPA" +%% "b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.1.2.3.4.ip6.arpa" %% 4. {1,2,3,4} => as 2. %% 5. {1,2,3,4,5,6,7,8} => as 3. +%% 6. Atom -> Recurse(String(Atom)) +%% 7. Term => {error, formerr} %% -nsdname({A,B,C,D}) -> - {ok, dn_in_addr_arpa(A,B,C,D)}; -nsdname({A,B,C,D,E,F,G,H}) -> - {ok, dn_ip6_int(A,B,C,D,E,F,G,H)}; +nsdname(Name) when is_atom(Name) -> + nsdname(atom_to_list(Name)); nsdname(Name) when is_list(Name) -> case inet_parse:visible_string(Name) of true -> case inet_parse:address(Name) of - {ok, Addr} -> - nsdname(Addr); + {ok, IP} -> + dn_ip(IP); _ -> {ok, Name} end; _ -> {error, formerr} end; -nsdname(Name) when is_atom(Name) -> - nsdname(atom_to_list(Name)); -nsdname(_) -> {error, formerr}. - -dn_in_addr_arpa(A,B,C,D) -> - integer_to_list(D) ++ - ("." ++ integer_to_list(C) ++ - ("." ++ integer_to_list(B) ++ - ("." ++ integer_to_list(A) ++ ".IN-ADDR.ARPA"))). - -dn_ip6_int(A,B,C,D,E,F,G,H) -> - dnib(H) ++ - (dnib(G) ++ - (dnib(F) ++ - (dnib(E) ++ - (dnib(D) ++ - (dnib(C) ++ - (dnib(B) ++ - (dnib(A) ++ "IP6.ARPA"))))))). - - - --compile({inline, [dnib/1, dnib/3]}). -dnib(X) -> - L = erlang:integer_to_list(X, 16), - dnib(4-length(L), L, []). +nsdname(IP) -> + dn_ip(IP). + +%% Return the domain name for a PTR lookup of +%% the argument IP address +%% +dn_ip({A,B,C,D}) when ?ip(A,B,C,D) -> + dn_ipv4([A,B,C,D], "in-addr.arpa"); +dn_ip({A,B,C,D,E,F,G,H}) when ?ip6(A,B,C,D,E,F,G,H) -> + dn_ipv6([A,B,C,D,E,F,G,H], "ip6.arpa"); +dn_ip(_) -> + {error, formerr}. + +dn_ipv4([], Dn) -> + {ok, Dn}; +dn_ipv4([A | As], Dn_0) when is_integer(A), A =< 255 -> + Dn = [$. | Dn_0], + if + A < 10 -> + dn_ipv4(As, dn_dec(A, Dn)); + A < 100 -> + dn_ipv4(As, dn_dec(A div 10, dn_dec(A rem 10, Dn))); + true -> + B = A rem 100, + dn_ipv4( + As, + dn_dec(A div 100, dn_dec(B div 10, dn_dec(B rem 10, Dn)))) + end. + +dn_ipv6([], Dn) -> + {ok, Dn}; +dn_ipv6([W | Ws], Dn) when is_integer(W), W =< 16#ffff -> + D = W band 16#f, W_1 = W bsr 4, + C = W_1 band 16#f, W_2 = W_1 bsr 4, + B = W_2 band 16#f, + A = W_2 bsr 4, + dn_ipv6(Ws, dn_hex(D, dn_hex(C, dn_hex(B, dn_hex(A, Dn))))). + +-compile({inline, [dn_dec/2, dn_hex/2]}). +dn_dec(N, Tail) when is_integer(N) -> + [N + $0 | Tail]. + +dn_hex(N, Tail) when is_integer(N) -> + if + N < 10 -> + [N + $0, $. | Tail]; + true -> + [(N - 10) + $a, $. | Tail] +end. + +%% Normalize an IPv4-compatible IPv6 address +%% into a plain IPv4 address %% -dnib(0, [], Acc) -> Acc; -dnib(0, [C|Cs], Acc) -> - dnib(0, Cs, [C,$.|Acc]); -dnib(N, Cs, Acc) -> - dnib(N-1, Cs, [$0,$.|Acc]). +norm_ip({0,0,0,0,0,16#ffff,G,H}) -> + A = G bsr 8, B = G band 16#ff, C = H bsr 8, D = H band 16#ff, + {A,B,C,D}; +norm_ip(IP) -> + IP. |