File 0365-Store-normalized-domain-in-unused-field.patch of Package erlang
From 1006fe5b101adee7a6bad699df60b95e002457c3 Mon Sep 17 00:00:00 2001
From: Raimo Niskanen <raimo@erlang.org>
Date: Thu, 17 Jun 2021 18:04:45 +0200
Subject: [PATCH 5/8] Store normalized domain in unused field
---
lib/kernel/src/inet_db.erl | 154 ++++++++++++++++++++++--------------
lib/kernel/src/inet_dns.hrl | 8 +-
2 files changed, 98 insertions(+), 64 deletions(-)
diff --git a/lib/kernel/src/inet_db.erl b/lib/kernel/src/inet_db.erl
index 2741810360..0a749030ef 100644
--- a/lib/kernel/src/inet_db.erl
+++ b/lib/kernel/src/inet_db.erl
@@ -584,19 +584,32 @@ db_get(Name) ->
end.
add_rr(RR) ->
- call({add_rr, RR}).
+ %% Questionable if we need to support this;
+ %% not used by OTP
+ %%
+ res_cache_answer([RR]).
add_rr(Domain, Class, Type, TTL, Data) ->
- call({add_rr, dns_rr_add(Domain, Class, Type, TTL, Data)}).
+ %% Only used from a test suite within OTP,
+ %% can be optimized to create the whole record inline
+ %% and call {add_rrs, [RR]} directly
+ RR =
+ #dns_rr{
+ domain = Domain, class = Class, type = Type,
+ ttl = TTL, data = Data},
+ res_cache_answer([RR]).
del_rr(Domain, Class, Type, Data) ->
- call({del_rr, dns_rr_match(Domain, Class, Type, Data)}).
-
-res_cache_answer(RRs) ->
- lists:foreach(fun add_rr/1, RRs).
+ call({del_rr, dns_rr_match(tolower(Domain), Class, Type, Data)}).
-
+res_cache_answer(RRs) ->
+ TM = times(),
+ call(
+ {add_rrs,
+ [RR#dns_rr{
+ bm = tolower(RR#dns_rr.domain), tm = TM, cnt = TM}
+ || RR <- RRs]}).
%%
%% getbyname (cache version)
@@ -706,7 +719,7 @@ lookup_rr(Domain, Class, Type) ->
%%
res_hostent_by_domain(Domain, Type, Rec) ->
RRs =
- [RR#dns_rr{domain = tolower(N)} ||
+ [RR#dns_rr{bm = tolower(N)} ||
#dns_rr{
domain = N,
class = in,
@@ -717,21 +730,22 @@ res_hostent_by_domain(Domain, Type, Rec) ->
Domain_1 = stripdot(Domain),
res_hostent_by_domain(Domain_1, tolower(Domain_1), [], [], Type, RRs).
-res_hostent_by_domain(Domain, LDomain, Aliases, LAliases, Type, RRs) ->
- case res_lookup_type(LDomain, Type, RRs) of
+res_hostent_by_domain(Domain, LcDomain, Aliases, LcAliases, Type, RRs) ->
+ case res_lookup_type(LcDomain, Type, RRs) of
[] ->
- case res_lookup_type(LDomain, ?S_CNAME, RRs) of
+ case res_lookup_type(LcDomain, ?S_CNAME, RRs) of
[] ->
{error, nxdomain};
[CName | _] ->
- LCName = tolower(CName),
- case lists:member(LCName, [LDomain | LAliases]) of
- true ->
+ LcCName = tolower(CName),
+ case lists:member(LcCName, [LcDomain | LcAliases]) of
+ true ->
+ %% CNAME loop
{error, nxdomain};
false ->
res_hostent_by_domain(
- CName, LCName,
- [Domain | Aliases], [LDomain | LAliases],
+ CName, LcCName,
+ [Domain | Aliases], [LcDomain | LcAliases],
Type, RRs)
end
end;
@@ -740,9 +754,9 @@ res_hostent_by_domain(Domain, LDomain, Aliases, LAliases, Type, RRs) ->
end.
%% newly resolved lookup address record
-res_lookup_type(Domain,Type,RRs) ->
+res_lookup_type(LcDomain, Type, RRs) ->
[R#dns_rr.data || R <- RRs,
- R#dns_rr.domain =:= Domain,
+ R#dns_rr.bm =:= LcDomain,
R#dns_rr.type =:= Type].
%%
@@ -763,7 +777,7 @@ gethostbyaddr(IP, HType, HLen, DnIP, DnIPs) ->
case lookup_cname(DnIP) of
[#dns_rr{data = DnIP_1} | _] ->
DnIPs_1 = [DnIP | DnIPs],
- %% CName loop protection
+ %% CNAME loop protection
case lists:member(DnIP_1, DnIPs_1) of
true ->
{error, nxdomain};
@@ -784,7 +798,7 @@ gethostbyaddr(IP, HType, HLen, DnIP, DnIPs) ->
res_gethostbyaddr(IP, Rec) ->
{ok, {IP1, HType, HLen}} = dnt(IP),
RRs =
- [RR#dns_rr{domain = tolower(N)} ||
+ [RR#dns_rr{bm = tolower(N)} ||
#dns_rr{
domain = N,
class = in,
@@ -810,7 +824,7 @@ ent_gethostbyaddr([RR|RRs], IP, AddrType, Length) ->
h_name = Domain,
%% Since a PTR record should point to
%% the canonical name, this Domain should
- %% have no canonical name, so it this really reasonable?
+ %% have no CNAME record, so is this really reasonable?
h_aliases = lookup_cname(Domain),
h_addr_list = [IP],
h_addrtype = AddrType,
@@ -942,7 +956,7 @@ init([]) ->
end,
Db = ets:new(inet_db, [public, named_table]),
reset_db(Db),
- CacheOpts = [public, bag, {keypos,#dns_rr.domain}, named_table],
+ CacheOpts = [public, bag, {keypos,#dns_rr.bm}, named_table],
Cache = ets:new(inet_cache, CacheOpts),
HostsByname = ets:new(inet_hosts_byname, [named_table]),
HostsByaddr = ets:new(inet_hosts_byaddr, [named_table]),
@@ -1030,10 +1044,9 @@ handle_call(Request, From, #state{db=Db}=State) ->
IP),
{reply, ok, State};
- {add_rr, RR} when is_record(RR, dns_rr) ->
- ?dbg("add_rr: ~p~n", [RR]),
- do_add_rr(RR, Db, State),
- {reply, ok, State};
+ {add_rrs, RRs} ->
+ ?dbg("add_rrs: ~p~n", [RRs]),
+ {reply, do_add_rrs(RRs, Db, State), State};
{del_rr, RR} when is_record(RR, dns_rr) ->
Cache = State#state.cache,
@@ -1677,35 +1690,40 @@ is_reqname(_) -> false.
%% #dns_rr.cnt is used to store the access time
%% instead of number of accesses.
%%
-do_add_rr(RR, Db, State) ->
+do_add_rrs(RRs, Db, State) ->
CacheDb = State#state.cache,
- TM = times(),
- case alloc_entry(Db, CacheDb, TM) of
+ do_add_rrs(RRs, Db, State, CacheDb).
+
+do_add_rrs([], _Db, _State, _CacheDb) ->
+ ok;
+do_add_rrs([RR | RRs], Db, State, CacheDb) ->
+ case alloc_entry(Db, CacheDb, #dns_rr.tm) of
true ->
%% Add to cache
+ %%
#dns_rr{
- domain = Domain, class = Class, type = Type,
+ bm = LcDomain, class = Class, type = Type,
data = Data} = RR,
DeleteRRs =
ets:match_object(
- CacheDb, dns_rr_match(Domain, Class, Type, Data)),
- InsertRR = RR#dns_rr{tm = TM, cnt = TM},
+ CacheDb, dns_rr_match(LcDomain, Class, Type, Data)),
%% Insert before delete to always have an RR present.
%% Watch out to not delete what we insert.
- case lists:member(InsertRR, DeleteRRs) of
+ case lists:member(RR, DeleteRRs) of
true ->
_ = [ets:delete_object(CacheDb, DelRR) ||
DelRR <- DeleteRRs,
- DelRR =/= InsertRR],
- true;
+ DelRR =/= RR],
+ ok;
false ->
- ets:insert(CacheDb, InsertRR),
+ ets:insert(CacheDb, RR),
_ = [ets:delete_object(CacheDb, DelRR) ||
DelRR <- DeleteRRs],
- true
- end;
+ ok
+ end,
+ do_add_rrs(RRs, Db, State, CacheDb);
false ->
- false
+ ok
end.
@@ -1729,23 +1747,15 @@ dns_rr_match_cnt(Cnt) ->
domain = '_', class = '_', type = '_', data = '_',
cnt = Cnt, tm = '_', ttl = '_', bm = '_', func = '_'}.
%%
-dns_rr_match(Domain, Class, Type) ->
+dns_rr_match(LcDomain, Class, Type) ->
#dns_rr{
- domain = Domain, class = Class, type = Type, data = '_',
- cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_'}.
+ domain = '_', class = Class, type = Type, data = '_',
+ cnt = '_', tm = '_', ttl = '_', bm = LcDomain, func = '_'}.
%%
-dns_rr_match(Domain, Class, Type, Data) ->
+dns_rr_match(LcDomain, Class, Type, Data) ->
#dns_rr{
- domain = Domain, class = Class, type = Type, data = Data,
- cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_'}.
-
-%% RR creation
--compile({inline, [dns_rr_add/5]}).
-%%
-dns_rr_add(Domain, Class, Type, TTL, Data) ->
- #dns_rr{
- domain = Domain, class = Class, type = Type,
- ttl = TTL, data = Data}.
+ domain = '_', class = Class, type = Type, data = Data,
+ cnt = '_', tm = '_', ttl = '_', bm = LcDomain, func = '_'}.
%% We are simultaneously updating the table from all clients
@@ -1805,8 +1815,8 @@ match_rr(CacheDb, [RR | RRs], Time, ResultRRs, InsertRRs, DeleteRRs) ->
-compile({inline, [match_rr_key/1]}).
match_rr_key(
- #dns_rr{domain = Domain, class = Class, type = Type, data = Data}) ->
- {Domain, Class, Type, Data}.
+ #dns_rr{bm = LcDomain, class = Class, type = Type, data = Data}) ->
+ {LcDomain, Class, Type, Data}.
%%
@@ -1817,14 +1827,36 @@ match_rr_key(
%% to much on stdlib. Furthermore string:to_lower/1
%% does not follow RFC 4343.
%%
-tolower([]) -> [];
-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)]
+tolower(Domain) ->
+ case rfc_4343_lc(Domain) of
+ ok ->
+ %% Optimization for already lowercased domain
+ Domain;
+ LcDomain ->
+ LcDomain
end.
+rfc_4343_lc([]) -> ok; % Optimization for already lowercased domain
+rfc_4343_lc([C | Cs]) when is_integer(C), 0 =< C, C =< 16#10FFFF ->
+ if
+ $A =< C, C =< $Z ->
+ [(C - $A) + $a |
+ case rfc_4343_lc(Cs) of
+ ok ->
+ Cs;
+ LCs ->
+ LCs
+ end];
+ true ->
+ case rfc_4343_lc(Cs) of
+ ok ->
+ ok;
+ LCs ->
+ [C | LCs]
+ end
+ 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.
diff --git a/lib/kernel/src/inet_dns.hrl b/lib/kernel/src/inet_dns.hrl
index 04ccb15b93..0b313f3bef 100644
--- a/lib/kernel/src/inet_dns.hrl
+++ b/lib/kernel/src/inet_dns.hrl
@@ -190,9 +190,11 @@
cnt = 0, %% access count
ttl = 0, %% time to live
data = [], %% raw data
- %%
+ %%
tm, %% creation time
- bm = [], %% Bitmap storing domain character case information.
+ bm = "", %% Used to be defined as:
+ %% Bitmap storing domain character case information
+ %% but now; Case normalized domain
func = false %% Was: Optional function calculating the data field.
%% Now: cache-flush Class flag from mDNS RFC 6762
}).
--
2.31.1
