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| author | Raimo Niskanen <raimo@erlang.org> | 2021-04-23 16:23:17 +0200 |
|---|---|---|
| committer | Raimo Niskanen <raimo@erlang.org> | 2021-07-02 12:33:01 +0200 |
| commit | d5f0138841ccc48592ac68283c5383297a986381 (patch) | |
| tree | f1efdaa806c0bd0d875c63f709065061d2913df4 | |
| parent | 0edbe63c02d0362ebcfe3b1c3bfbdce47d2d146f (diff) | |
| download | erlang-d5f0138841ccc48592ac68283c5383297a986381.tar.gz | |
Use case insensitive domain compare
| -rw-r--r-- | lib/kernel/src/inet_db.erl | 39 | ||||
| -rw-r--r-- | lib/kernel/src/inet_res.erl | 4 |
2 files changed, 39 insertions, 4 deletions
diff --git a/lib/kernel/src/inet_db.erl b/lib/kernel/src/inet_db.erl index 90e2f66365..2741810360 100644 --- a/lib/kernel/src/inet_db.erl +++ b/lib/kernel/src/inet_db.erl @@ -71,7 +71,7 @@ -export([res_gethostbyaddr/2,res_hostent_by_domain/3]). -export([res_update_conf/0, res_update_hosts/0]). %% inet help functions --export([tolower/1]). +-export([tolower/1, eq_domains/2]). -ifdef(DEBUG). -define(dbg(Fmt, Args), io:format(Fmt, Args)). -else. @@ -1818,13 +1818,48 @@ match_rr_key( %% does not follow RFC 4343. %% tolower([]) -> []; -tolower([C|Cs]) when is_integer(C) -> +tolower([C|Cs]) when is_integer(C), 0 =< C, C =< 16#10FFFF -> if C >= $A, C =< $Z -> [(C-$A)+$a|tolower(Cs)]; true -> [C|tolower(Cs)] end. +%% Case insensitive domain name comparison according to RFC 4343 +%% "Domain Name System (DNS) Case Insensitivity Clarification", +%% i.e regard $a through $z as equal to $A through $Z. +%% +eq_domains([A | As], [B | Bs]) -> + if + is_integer(A), 0 =< A, A =< 16#10FFFF, + is_integer(B), 0 =< B, B =< 16#10FFFF -> + %% An upper bound of 255 would be right right now, + %% but this algorithm works for any integer. That + %% guard just gives the compiler the opportuinity + %% to optimize bit operations for machine word size, + %% so we might as well use the Unicode upper bound instead. + Xor = (A bxor B), + if + Xor =:= 0 -> + eq_domains(As, Bs); + Xor =:= ($A bxor $a) -> + And = (A band B), + if + ($A band $a) =< And, And =< ($Z band $z) -> + eq_domains(As, Bs); + true -> + false + end; + true -> + false + end + end; +eq_domains([], []) -> + true; +eq_domains(As, Bs) when is_list(As), is_list(Bs) -> + false. + + 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.int". diff --git a/lib/kernel/src/inet_res.erl b/lib/kernel/src/inet_res.erl index 1b6344f372..e238cfd2a1 100644 --- a/lib/kernel/src/inet_res.erl +++ b/lib/kernel/src/inet_res.erl @@ -1110,8 +1110,8 @@ decode_answer_noerror( andalso (RR#dns_query.type =:= Q_RR#dns_query.type) andalso - (inet_db:tolower(RR#dns_query.domain) =:= - inet_db:tolower(Q_RR#dns_query.domain)) + inet_db:eq_domains( + RR#dns_query.domain, Q_RR#dns_query.domain) of true -> {ok, Msg}; |