%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1997-2016. 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. %% You may obtain a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, software %% distributed under the License is distributed on an "AS IS" BASIS, %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %% See the License for the specific language governing permissions and %% limitations under the License. %% %% %CopyrightEnd% %% -module(inet_db). %% Store info about ip addresses, names, aliases host files resolver %% options %% If the macro DEBUG is defined during compilation, %% debug printouts are done through erlang:display/1. %% Activate this feature by starting the compiler %% with> erlc -DDEBUG ... %% or by> setenv ERL_COMPILER_FLAGS DEBUG %% before running make (in the OTP make system) %% (the example is for tcsh) %% External exports -export([start/0, start_link/0, stop/0, reset/0, clear_cache/0]). -export([add_rr/1,add_rr/5,del_rr/4]). -export([add_ns/1,add_ns/2, ins_ns/1, ins_ns/2, del_ns/2, del_ns/1, del_ns/0]). -export([add_alt_ns/1,add_alt_ns/2, ins_alt_ns/1, ins_alt_ns/2, del_alt_ns/2, del_alt_ns/1, del_alt_ns/0]). -export([add_search/1,ins_search/1,del_search/1, del_search/0]). -export([set_lookup/1, set_recurse/1]). -export([set_socks_server/1, set_socks_port/1, add_socks_methods/1, del_socks_methods/1, del_socks_methods/0, add_socks_noproxy/1, del_socks_noproxy/1]). -export([set_cache_size/1, set_cache_refresh/1]). -export([set_timeout/1, set_retry/1, set_inet6/1, set_usevc/1]). -export([set_edns/1, set_udp_payload_size/1]). -export([set_resolv_conf/1, set_hosts_file/1, get_hosts_file/0]). -export([tcp_module/0, set_tcp_module/1]). -export([udp_module/0, set_udp_module/1]). -export([sctp_module/0,set_sctp_module/1]). -export([register_socket/2, unregister_socket/1, lookup_socket/1]). %% Host name & domain -export([set_hostname/1, set_domain/1]). -export([gethostname/0]). %% file interface -export([add_host/2, del_host/1, clear_hosts/0, add_hosts/1]). -export([add_resolv/1]). -export([add_rc/1, add_rc_bin/1, add_rc_list/1, get_rc/0]). -export([res_option/1, res_option/2, res_check_option/2]). -export([socks_option/1]). -export([getbyname/2, get_searchlist/0]). -export([gethostbyaddr/1]). -export([res_gethostbyaddr/2,res_hostent_by_domain/3]). -export([res_update_conf/0, res_update_hosts/0]). %% inet help functions -export([tolower/1]). -ifdef(DEBUG). -define(dbg(Fmt, Args), io:format(Fmt, Args)). -else. -define(dbg(Fmd, Args), ok). -endif. -include_lib("kernel/include/file.hrl"). %% gen_server callbacks -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2]). -record(state, {db, %% resolver data cache, %% bag of resource records hosts_byname, %% hosts table hosts_byaddr, %% hosts table hosts_file_byname, %% hosts table from system file hosts_file_byaddr, %% hosts table from system file cache_timer %% timer reference for refresh }). -type state() :: #state{}. -include("inet.hrl"). -include("inet_int.hrl"). -include("inet_res.hrl"). -include("inet_dns.hrl"). -include("inet_config.hrl"). %%%---------------------------------------------------------------------- %%% API %%%---------------------------------------------------------------------- start() -> case gen_server:start({local, inet_db}, inet_db, [], []) of {ok, _Pid}=Ok -> inet_config:init(), Ok; Error -> Error end. start_link() -> case gen_server:start_link({local, inet_db}, inet_db, [], []) of {ok, _Pid}=Ok -> inet_config:init(), Ok; Error -> Error end. call(Req) -> gen_server:call(inet_db, Req, infinity). stop() -> call(stop). reset() -> call(reset). %% insert all resolve options from this file (MAY GO) add_resolv(File) -> case inet_parse:resolv(File) of {ok, Res} -> add_rc_list(Res); Error -> Error end. %% add all aliases from this hosts file (MAY GO) add_hosts(File) -> case inet_parse:hosts(File) of {ok, Res} -> lists:foreach( fun({IP, Name, Aliases}) -> add_host(IP, [Name|Aliases]) end, Res); Error -> Error end. add_host(IP, Names) -> call({add_host, IP, Names}). del_host(IP) -> call({del_host, IP}). clear_hosts() -> call(clear_hosts). %% add to the end of name server list add_ns(IP) -> add_ns(IP,?NAMESERVER_PORT). add_ns(IP,Port) -> call({listop, nameservers, add, {IP,Port}}). %% insert at head of name server list ins_ns(IP) -> ins_ns(IP, ?NAMESERVER_PORT). ins_ns(IP,Port) -> call({listop, nameservers, ins, {IP,Port}}). %% delete this name server entry (delete all ns having this ip) del_ns(IP) -> del_ns(IP, ?NAMESERVER_PORT). del_ns(IP, Port) -> call({listop, nameservers, del, {IP,Port}}). del_ns() -> call({listdel, nameservers}). %% ALTERNATIVE NAME SERVER %% add to the end of name server list add_alt_ns(IP) -> add_alt_ns(IP, ?NAMESERVER_PORT). add_alt_ns(IP,Port) -> call({listop, alt_nameservers, add, {IP,Port}}). %% insert at head of name server list ins_alt_ns(IP) -> ins_alt_ns(IP, ?NAMESERVER_PORT). ins_alt_ns(IP,Port) -> call({listop, alt_nameservers, ins, {IP,Port}}). %% delete this name server entry del_alt_ns(IP) -> del_alt_ns(IP, ?NAMESERVER_PORT). del_alt_ns(IP, Port) -> call({listop, alt_nameservers, del, {IP,Port}}). del_alt_ns() -> call({listdel, alt_nameservers}). %% add this domain to the search list add_search(Domain) when is_list(Domain) -> call({listop, search, add, Domain}). ins_search(Domain) when is_list(Domain) -> call({listop, search, ins, Domain}). del_search(Domain) -> call({listop, search, del, Domain}). del_search() -> call({listdel, search}). %% set host name used by inet %% Should only be used by inet_config at startup! set_hostname(Name) -> call({set_hostname, Name}). %% set default domain set_domain(Domain) -> res_option(domain, Domain). %% set lookup methods set_lookup(Methods) -> res_option(lookup, Methods). %% resolver set_recurse(Flag) -> res_option(recurse, Flag). set_timeout(Time) -> res_option(timeout, Time). set_retry(N) -> res_option(retry, N). set_inet6(Bool) -> res_option(inet6, Bool). set_usevc(Bool) -> res_option(usevc, Bool). set_edns(Version) -> res_option(edns, Version). set_udp_payload_size(Size) -> res_option(udp_payload_size, Size). set_resolv_conf(Fname) -> res_option(resolv_conf, Fname). set_hosts_file(Fname) -> res_option(hosts_file, Fname). get_hosts_file() -> get_rc_hosts([], [], inet_hosts_file_byname). %% set socks options set_socks_server(Server) -> call({set_socks_server, Server}). set_socks_port(Port) -> call({set_socks_port, Port}). add_socks_methods(Ms) -> call({add_socks_methods,Ms}). del_socks_methods(Ms) -> call({del_socks_methods,Ms}). del_socks_methods() -> call(del_socks_methods). add_socks_noproxy({Net,Mask}) -> call({add_socks_noproxy, {Net,Mask}}). del_socks_noproxy(Net) -> call({del_socks_noproxy, Net}). %% cache options set_cache_size(Limit) -> call({set_cache_size, Limit}). set_cache_refresh(Time) -> call({set_cache_refresh, Time}). clear_cache() -> call(clear_cache). set_tcp_module(Module) -> call({set_tcp_module, Module}). tcp_module() -> db_get(tcp_module). set_udp_module(Module) -> call({set_udp_module, Module}). udp_module() -> db_get(udp_module). set_sctp_module(Family)-> call({set_sctp_module,Family}). sctp_module()-> db_get(sctp_module). %% Add an inetrc file add_rc(File) -> case file:consult(File) of {ok, List} -> add_rc_list(List); Error -> Error end. %% Add an inetrc binary term must be a rc list add_rc_bin(Bin) -> case catch binary_to_term(Bin) of List when is_list(List) -> add_rc_list(List); _ -> {error, badarg} end. add_rc_list(List) -> call({add_rc_list, List}). %% All kind of flavors ! translate_lookup(["bind" | Ls]) -> [dns | translate_lookup(Ls)]; translate_lookup(["dns" | Ls]) -> [dns | translate_lookup(Ls)]; translate_lookup(["hosts" | Ls]) -> [file | translate_lookup(Ls)]; translate_lookup(["files" | Ls]) -> [file | translate_lookup(Ls)]; translate_lookup(["file" | Ls]) -> [file | translate_lookup(Ls)]; translate_lookup(["yp" | Ls]) -> [yp | translate_lookup(Ls)]; translate_lookup(["nis" | Ls]) -> [nis | translate_lookup(Ls)]; translate_lookup(["nisplus" | Ls]) -> [nisplus | translate_lookup(Ls)]; translate_lookup(["native" | Ls]) -> [native | translate_lookup(Ls)]; translate_lookup([M | Ls]) when is_atom(M) -> translate_lookup([atom_to_list(M) | Ls]); translate_lookup([_ | Ls]) -> translate_lookup(Ls); translate_lookup([]) -> []. valid_lookup() -> [dns, file, yp, nis, nisplus, native]. %% Reconstruct an inetrc sturcture from inet_db get_rc() -> get_rc([hosts, domain, nameservers, search, alt_nameservers, timeout, retry, inet6, usevc, edns, udp_payload_size, resolv_conf, hosts_file, socks5_server, socks5_port, socks5_methods, socks5_noproxy, udp, sctp, tcp, host, cache_size, cache_refresh, lookup], []). get_rc([K | Ks], Ls) -> case K of hosts -> get_rc_hosts(Ks, Ls, inet_hosts_byname); domain -> get_rc(domain, res_domain, "", Ks, Ls); nameservers -> get_rc_ns(db_get(res_ns),nameservers,Ks,Ls); alt_nameservers -> get_rc_ns(db_get(res_alt_ns),alt_nameservers,Ks,Ls); search -> get_rc(search, res_search, [], Ks, Ls); timeout -> get_rc(timeout,res_timeout,?RES_TIMEOUT, Ks,Ls); retry -> get_rc(retry, res_retry, ?RES_RETRY, Ks, Ls); inet6 -> get_rc(inet6, res_inet6, false, Ks, Ls); usevc -> get_rc(usevc, res_usevc, false, Ks, Ls); edns -> get_rc(edns, res_edns, false, Ks, Ls); udp_payload_size -> get_rc(udp_payload_size, res_udp_payload_size, ?DNS_UDP_PAYLOAD_SIZE, Ks, Ls); resolv_conf -> get_rc(resolv_conf, res_resolv_conf, undefined, Ks, Ls); hosts_file -> get_rc(hosts_file, res_hosts_file, undefined, Ks, Ls); tcp -> get_rc(tcp, tcp_module, ?DEFAULT_TCP_MODULE, Ks, Ls); udp -> get_rc(udp, udp_module, ?DEFAULT_UDP_MODULE, Ks, Ls); sctp -> get_rc(sctp, sctp_module, ?DEFAULT_SCTP_MODULE, Ks, Ls); lookup -> get_rc(lookup, res_lookup, [native,file], Ks, Ls); cache_size -> get_rc(cache_size, cache_size, ?CACHE_LIMIT, Ks, Ls); cache_refresh -> get_rc(cache_refresh, cache_refresh_interval,?CACHE_REFRESH,Ks,Ls); socks5_server -> get_rc(socks5_server, socks5_server, "", Ks, Ls); socks5_port -> get_rc(socks5_port,socks5_port,?IPPORT_SOCKS,Ks,Ls); socks5_methods -> get_rc(socks5_methods,socks5_methods,[none],Ks,Ls); socks5_noproxy -> case db_get(socks5_noproxy) of [] -> get_rc(Ks, Ls); NoProxy -> get_rc_noproxy(NoProxy, Ks, Ls) end; _ -> get_rc(Ks, Ls) end; get_rc([], Ls) -> lists:reverse(Ls). get_rc(Name, Key, Default, Ks, Ls) -> case db_get(Key) of Default -> get_rc(Ks, Ls); Value -> get_rc(Ks, [{Name, Value} | Ls]) end. get_rc_noproxy([{Net,Mask} | Ms], Ks, Ls) -> get_rc_noproxy(Ms, Ks, [{socks5_noproxy, Net, Mask} | Ls]); get_rc_noproxy([], Ks, Ls) -> get_rc(Ks, Ls). get_rc_ns([{IP,?NAMESERVER_PORT} | Ns], Tag, Ks, Ls) -> get_rc_ns(Ns, Tag, Ks, [{Tag, IP} | Ls]); get_rc_ns([{IP,Port} | Ns], Tag, Ks, Ls) -> get_rc_ns(Ns, Tag, Ks, [{Tag, IP, Port} | Ls]); get_rc_ns([], _Tag, Ks, Ls) -> get_rc(Ks, Ls). get_rc_hosts(Ks, Ls, Tab) -> case lists:keysort(3, ets:tab2list(Tab)) of [] -> get_rc(Ks, Ls); [{N,_,IP}|Hosts] -> get_rc_hosts(Ks, Ls, IP, Hosts, [N]) end. get_rc_hosts(Ks, Ls, IP, [], Ns) -> get_rc(Ks, [{host,IP,lists:reverse(Ns)}|Ls]); get_rc_hosts(Ks, Ls, IP, [{N,_,IP}|Hosts], Ns) -> get_rc_hosts(Ks, Ls, IP, Hosts, [N|Ns]); get_rc_hosts(Ks, Ls, IP, [{N,_,NewIP}|Hosts], Ns) -> [{host,IP,lists:reverse(Ns)}|get_rc_hosts(Ks, Ls, NewIP, Hosts, [N])]. %% %% Resolver options %% res_option(next_id) -> Cnt = ets:update_counter(inet_db, res_id, 1), case Cnt band 16#ffff of 0 -> ets:update_counter(inet_db, res_id, -Cnt), 0; Id -> Id end; res_option(Option) -> case res_optname(Option) of undefined -> erlang:error(badarg, [Option]); ResOptname -> db_get(ResOptname) end. res_option(Option, Value) -> case res_optname(Option) of undefined -> erlang:error(badarg, [Option,Value]); _ -> call({res_set,Option,Value}) end. res_optname(nameserver) -> res_ns; %% Legacy res_optname(alt_nameserver) -> res_alt_ns; %% Legacy res_optname(nameservers) -> res_ns; res_optname(alt_nameservers) -> res_alt_ns; res_optname(domain) -> res_domain; res_optname(lookup) -> res_lookup; res_optname(recurse) -> res_recurse; res_optname(search) -> res_search; res_optname(retry) -> res_retry; res_optname(timeout) -> res_timeout; res_optname(inet6) -> res_inet6; res_optname(usevc) -> res_usevc; res_optname(edns) -> res_edns; res_optname(udp_payload_size) -> res_udp_payload_size; res_optname(resolv_conf) -> res_resolv_conf; res_optname(resolv_conf_name) -> res_resolv_conf; res_optname(hosts_file) -> res_hosts_file; res_optname(hosts_file_name) -> res_hosts_file; res_optname(_) -> undefined. res_check_option(nameserver, NSs) -> %% Legacy res_check_list(NSs, fun res_check_ns/1); res_check_option(alt_nameserver, NSs) -> %% Legacy res_check_list(NSs, fun res_check_ns/1); res_check_option(nameservers, NSs) -> res_check_list(NSs, fun res_check_ns/1); res_check_option(alt_nameservers, NSs) -> res_check_list(NSs, fun res_check_ns/1); res_check_option(domain, Dom) -> inet_parse:visible_string(Dom); res_check_option(lookup, Methods) -> try lists_subtract(Methods, valid_lookup()) of [] -> true; _ -> false catch error:_ -> false end; res_check_option(recurse, R) when R =:= 0; R =:= 1 -> true; %% Legacy res_check_option(recurse, R) when is_boolean(R) -> true; res_check_option(search, SearchList) -> res_check_list(SearchList, fun res_check_search/1); res_check_option(retry, N) when is_integer(N), N > 0 -> true; res_check_option(timeout, T) when is_integer(T), T > 0 -> true; res_check_option(inet6, Bool) when is_boolean(Bool) -> true; res_check_option(usevc, Bool) when is_boolean(Bool) -> true; res_check_option(edns, V) when V =:= false; V =:= 0 -> true; res_check_option(udp_payload_size, S) when is_integer(S), S >= 512 -> true; res_check_option(resolv_conf, "") -> true; res_check_option(resolv_conf, F) -> res_check_option_absfile(F); res_check_option(resolv_conf_name, "") -> true; res_check_option(resolv_conf_name, F) -> res_check_option_absfile(F); res_check_option(hosts_file, "") -> true; res_check_option(hosts_file, F) -> res_check_option_absfile(F); res_check_option(hosts_file_name, "") -> true; res_check_option(hosts_file_name, F) -> res_check_option_absfile(F); res_check_option(_, _) -> false. res_check_option_absfile(F) -> try filename:pathtype(F) of absolute -> true; _ -> false catch _:_ -> false end. res_check_list([], _Fun) -> true; res_check_list([H|T], Fun) -> Fun(H) andalso res_check_list(T, Fun); res_check_list(_, _Fun) -> false. res_check_ns({{A,B,C,D,E,F,G,H}, Port}) when ?ip6(A,B,C,D,E,F,G,H), Port band 65535 =:= Port -> true; res_check_ns({{A,B,C,D}, Port}) when ?ip(A,B,C,D), Port band 65535 =:= Port -> true; res_check_ns(_) -> false. res_check_search("") -> true; res_check_search(Dom) -> inet_parse:visible_string(Dom). socks_option(server) -> db_get(socks5_server); socks_option(port) -> db_get(socks5_port); socks_option(methods) -> db_get(socks5_methods); socks_option(noproxy) -> db_get(socks5_noproxy). gethostname() -> db_get(hostname). res_update_conf() -> res_update(res_resolv_conf, res_resolv_conf_tm, res_resolv_conf_info, set_resolv_conf_tm, fun set_resolv_conf/1). res_update_hosts() -> res_update(res_hosts_file, res_hosts_file_tm, res_hosts_file_info, set_hosts_file_tm, fun set_hosts_file/1). res_update(Tag, TagTm, TagInfo, TagSetTm, SetFun) -> case db_get(TagTm) of undefined -> ok; TM -> case times() of Now when Now >= TM + ?RES_FILE_UPDATE_TM -> case db_get(Tag) of undefined -> SetFun(""); "" -> SetFun(""); File -> case erl_prim_loader:read_file_info(File) of {ok, Finfo0} -> Finfo = Finfo0#file_info{access = undefined, atime = undefined}, case db_get(TagInfo) of Finfo -> call({TagSetTm, Now}); _ -> SetFun(File) end; _ -> call({TagSetTm, Now}), error end end; _ -> ok end end. db_get(Name) -> case ets:lookup(inet_db, Name) of [] -> undefined; [{_,Val}] -> Val end. add_rr(RR) -> call({add_rr, RR}). add_rr(Domain, Class, Type, TTL, Data) -> call({add_rr, #dns_rr { domain = Domain, class = Class, type = Type, ttl = TTL, data = Data}}). del_rr(Domain, Class, Type, Data) -> call({del_rr, #dns_rr { domain = Domain, class = Class, type = Type, cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_', data = Data}}). res_cache_answer(Rec) -> lists:foreach( fun(RR) -> add_rr(RR) end, Rec#dns_rec.anlist). %% %% getbyname (cache version) %% %% This function and inet_res:res_getbyname/3 must look up names %% in the same manner, but not from the same places. %% getbyname(Name, Type) -> {EmbeddedDots, TrailingDot} = inet_parse:dots(Name), Dot = if TrailingDot -> ""; true -> "." end, if TrailingDot -> hostent_by_domain(Name, Type); EmbeddedDots =:= 0 -> getbysearch(Name, Dot, get_searchlist(), Type, {error,nxdomain}); true -> case hostent_by_domain(Name, Type) of {error,_}=Error -> getbysearch(Name, Dot, get_searchlist(), Type, Error); Other -> Other end end. getbysearch(Name, Dot, [Dom | Ds], Type, _) -> case hostent_by_domain(Name ++ Dot ++ Dom, Type) of {ok, _HEnt}=Ok -> Ok; Error -> getbysearch(Name, Dot, Ds, Type, Error) end; getbysearch(_Name, _Dot, [], _Type, Error) -> Error. %% %% get_searchlist %% get_searchlist() -> case res_option(search) of [] -> [res_option(domain)]; L -> L end. make_hostent(Name, Addrs, Aliases, ?S_A) -> #hostent { h_name = Name, h_addrtype = inet, h_length = 4, h_addr_list = Addrs, h_aliases = Aliases }; make_hostent(Name, Addrs, Aliases, ?S_AAAA) -> #hostent { h_name = Name, h_addrtype = inet6, h_length = 16, h_addr_list = Addrs, h_aliases = Aliases }; make_hostent(Name, Datas, Aliases, Type) -> %% Use #hostent{} for other Types as well ! #hostent { h_name = Name, h_addrtype = Type, h_length = length(Datas), h_addr_list = Datas, h_aliases = Aliases }. hostent_by_domain(Domain, Type) -> ?dbg("hostent_by_domain: ~p~n", [Domain]), hostent_by_domain(stripdot(Domain), [], [], Type). hostent_by_domain(Domain, Aliases, LAliases, Type) -> case lookup_type(Domain, Type) of [] -> case lookup_cname(Domain) of [] -> {error, nxdomain}; [CName | _] -> LDomain = tolower(Domain), case lists:member(CName, [LDomain | LAliases]) of true -> {error, nxdomain}; false -> hostent_by_domain(CName, [Domain | Aliases], [LDomain | LAliases], Type) end end; Addrs -> {ok, make_hostent(Domain, Addrs, Aliases, Type)} end. %% lookup address record lookup_type(Domain, Type) -> [R#dns_rr.data || R <- lookup_rr(Domain, in, Type) ]. %% lookup canonical name lookup_cname(Domain) -> [R#dns_rr.data || R <- lookup_rr(Domain, in, ?S_CNAME) ]. %% Have to do all lookups (changes to the db) in the %% process in order to make it possible to refresh the cache. lookup_rr(Domain, Class, Type) -> call({lookup_rr, Domain, Class, Type}). %% %% hostent_by_domain (newly resolved version) %% match data field directly and cache RRs. %% res_hostent_by_domain(Domain, Type, Rec) -> RRs = lists:map(fun lower_rr/1, Rec#dns_rec.anlist), res_cache_answer(Rec#dns_rec{anlist = RRs}), ?dbg("res_hostent_by_domain: ~p - ~p~n", [Domain, RRs]), res_hostent_by_domain(stripdot(Domain), [], [], Type, RRs). res_hostent_by_domain(Domain, Aliases, LAliases, Type, RRs) -> LDomain = tolower(Domain), case res_lookup_type(LDomain, Type, RRs) of [] -> case res_lookup_type(LDomain, ?S_CNAME, RRs) of [] -> {error, nxdomain}; [CName | _] -> case lists:member(tolower(CName), [LDomain | LAliases]) of true -> {error, nxdomain}; false -> res_hostent_by_domain(CName, [Domain | Aliases], [LDomain | LAliases], Type, RRs) end end; Addrs -> {ok, make_hostent(Domain, Addrs, Aliases, Type)} end. %% newly resolved lookup address record res_lookup_type(Domain,Type,RRs) -> [R#dns_rr.data || R <- RRs, R#dns_rr.domain =:= Domain, R#dns_rr.type =:= Type]. %% %% gethostbyaddr (cache version) %% match data field directly %% gethostbyaddr(IP) -> case dnip(IP) of {ok, {IP1, HType, HLen, DnIP}} -> RRs = match_rr(#dns_rr { domain = DnIP, class = in, type = ptr, cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_', data = '_' }), ent_gethostbyaddr(RRs, IP1, HType, HLen); Error -> Error end. %% %% res_gethostbyaddr (newly resolved version) %% match data field directly and cache RRs. %% res_gethostbyaddr(IP, Rec) -> {ok, {IP1, HType, HLen}} = dnt(IP), RRs = lists:map(fun lower_rr/1, Rec#dns_rec.anlist), res_cache_answer(Rec#dns_rec{anlist = RRs}), ent_gethostbyaddr(Rec#dns_rec.anlist, IP1, HType, HLen). ent_gethostbyaddr(RRs, IP, AddrType, Length) -> case RRs of [] -> {error, nxdomain}; [RR|TR] -> %% debug if TR =/= [] -> ?dbg("gethostbyaddr found extra=~p~n", [TR]); true -> ok end, Domain = RR#dns_rr.data, H = #hostent { h_name = Domain, h_aliases = lookup_cname(Domain), h_addr_list = [IP], h_addrtype = AddrType, h_length = Length }, {ok, H} end. dnip(IP) -> case dnt(IP) of {ok,{IP1 = {A,B,C,D}, inet, HLen}} -> {ok,{IP1, inet, HLen, dn_in_addr_arpa(A,B,C,D)}}; {ok,{IP1 = {A,B,C,D,E,F,G,H}, inet6, HLen}} -> {ok,{IP1, inet6, HLen, dn_ip6_int(A,B,C,D,E,F,G,H)}}; _ -> {error, formerr} end. dnt(IP = {A,B,C,D}) when ?ip(A,B,C,D) -> {ok, {IP, inet, 4}}; dnt({0,0,0,0,0,16#ffff,G,H}) when is_integer(G+H) -> A = G div 256, B = G rem 256, C = H div 256, D = H rem 256, {ok, {{A,B,C,D}, inet, 4}}; dnt(IP = {A,B,C,D,E,F,G,H}) when ?ip6(A,B,C,D,E,F,G,H) -> {ok, {IP, inet6, 16}}; dnt(_) -> {error, formerr}. %% %% Register socket Modules %% register_socket(Socket, Module) when is_port(Socket), is_atom(Module) -> try erlang:port_set_data(Socket, Module) catch error:badarg -> false end. unregister_socket(Socket) when is_port(Socket) -> ok. %% not needed any more lookup_socket(Socket) when is_port(Socket) -> try erlang:port_get_data(Socket) of Module when is_atom(Module) -> {ok,Module}; _ -> {error,closed} catch error:badarg -> {error,closed} end. %%%---------------------------------------------------------------------- %%% Callback functions from gen_server %%%---------------------------------------------------------------------- %%---------------------------------------------------------------------- %% Func: init/1 %% Returns: {ok, State} | %% {ok, State, Timeout} | %% {stop, Reason} %%---------------------------------------------------------------------- %% INET DB ENTRY TYPES: %% %% KEY VALUE - DESCRIPTION %% %% hostname String - SHORT host name %% %% Resolver options %% ---------------- %% res_ns [Nameserver] - list of name servers %% res_alt_ns [AltNameServer] - list of alternate name servers (nxdomain) %% res_search [Domain] - list of domains for short names %% res_domain Domain - local domain for short names %% res_recurse Bool - recursive query %% res_usevc Bool - use tcp only %% res_id Integer - NS query identifier %% res_retry Integer - Retry count for UDP query %% res_timeout Integer - UDP query timeout before retry %% res_inet6 Bool - address family inet6 for gethostbyname/1 %% res_usevc Bool - use Virtual Circuit (TCP) %% res_edns false|Integer - false or EDNS version %% res_udp_payload_size Integer - size for EDNS, both query and reply %% res_resolv_conf Filename - file to watch for resolver config i.e %% {res_ns, res_search} %% res_hosts_file Filename - file to watch for hosts config %% %% Socks5 options %% -------------- %% socks5_server Server - IP address of the socks5 server %% socks5_port Port - TCP port of the socks5 server %% socks5_methods Ls - List of authentication methods %% socks5_noproxy IPs - List of {Net,Subnetmask} %% %% Generic tcp/udp options %% ----------------------- %% tcp_module Module - The default gen_tcp module %% udp_module Module - The default gen_udp module %% sctp_module Module - The default gen_sctp module %% %% Distribution options %% -------------------- %% {node_auth,N} Ls - List of authentication for node N %% {node_crypt,N} Ls - List of encryption methods for node N %% node_auth Ls - Default authenication %% node_crypt Ls - Default encryption %% -spec init([]) -> {'ok', state()}. init([]) -> process_flag(trap_exit, true), Db = ets:new(inet_db, [public, named_table]), reset_db(Db), CacheOpts = [public, bag, {keypos,#dns_rr.domain}, named_table], Cache = ets:new(inet_cache, CacheOpts), BynameOpts = [protected, bag, named_table, {keypos,1}], ByaddrOpts = [protected, bag, named_table, {keypos,3}], HostsByname = ets:new(inet_hosts_byname, BynameOpts), HostsByaddr = ets:new(inet_hosts_byaddr, ByaddrOpts), HostsFileByname = ets:new(inet_hosts_file_byname, BynameOpts), HostsFileByaddr = ets:new(inet_hosts_file_byaddr, ByaddrOpts), {ok, #state{db = Db, cache = Cache, hosts_byname = HostsByname, hosts_byaddr = HostsByaddr, hosts_file_byname = HostsFileByname, hosts_file_byaddr = HostsFileByaddr, cache_timer = init_timer() }}. reset_db(Db) -> ets:insert(Db, {hostname, []}), ets:insert(Db, {res_ns, []}), ets:insert(Db, {res_alt_ns, []}), ets:insert(Db, {res_search, []}), ets:insert(Db, {res_domain, ""}), ets:insert(Db, {res_lookup, []}), ets:insert(Db, {res_recurse, true}), ets:insert(Db, {res_usevc, false}), ets:insert(Db, {res_id, 0}), ets:insert(Db, {res_retry, ?RES_RETRY}), ets:insert(Db, {res_timeout, ?RES_TIMEOUT}), ets:insert(Db, {res_inet6, false}), ets:insert(Db, {res_edns, false}), ets:insert(Db, {res_udp_payload_size, ?DNS_UDP_PAYLOAD_SIZE}), ets:insert(Db, {cache_size, ?CACHE_LIMIT}), ets:insert(Db, {cache_refresh_interval,?CACHE_REFRESH}), ets:insert(Db, {socks5_server, ""}), ets:insert(Db, {socks5_port, ?IPPORT_SOCKS}), ets:insert(Db, {socks5_methods, [none]}), ets:insert(Db, {socks5_noproxy, []}), ets:insert(Db, {tcp_module, ?DEFAULT_TCP_MODULE}), ets:insert(Db, {udp_module, ?DEFAULT_UDP_MODULE}), ets:insert(Db, {sctp_module, ?DEFAULT_SCTP_MODULE}). %%---------------------------------------------------------------------- %% Func: handle_call/3 %% Returns: {reply, Reply, State} | %% {reply, Reply, State, Timeout} | %% {noreply, State} | %% {noreply, State, Timeout} | %% {stop, Reason, Reply, State} | (terminate/2 is called) %% {stop, Reason, Reply, State} (terminate/2 is called) %%---------------------------------------------------------------------- -spec handle_call(term(), {pid(), term()}, state()) -> {'reply', term(), state()} | {'stop', 'normal', 'ok', state()}. handle_call(Request, From, #state{db=Db}=State) -> case Request of {load_hosts_file,IPNmAs} when is_list(IPNmAs) -> NIPs = lists:flatten( [ [{N, if tuple_size(IP) =:= 4 -> inet; tuple_size(IP) =:= 8 -> inet6 end,IP} || N <- [Nm|As]] || {IP,Nm,As} <- IPNmAs]), Byname = State#state.hosts_file_byname, Byaddr = State#state.hosts_file_byaddr, ets:delete_all_objects(Byname), ets:delete_all_objects(Byaddr), %% Byname has lowercased names while Byaddr keep the name casing. %% This is to be able to reconstruct the original %% /etc/hosts entry. ets:insert(Byname, [{tolower(N),Type,IP} || {N,Type,IP} <- NIPs]), ets:insert(Byaddr, NIPs), {reply, ok, State}; {add_host,{A,B,C,D}=IP,[N|As]=Names} when ?ip(A,B,C,D), is_list(N), is_list(As) -> do_add_host(State#state.hosts_byname, State#state.hosts_byaddr, Names, inet, IP), {reply, ok, State}; {add_host,{A,B,C,D,E,F,G,H}=IP,[N|As]=Names} when ?ip6(A,B,C,D,E,F,G,H), is_list(N), is_list(As) -> do_add_host(State#state.hosts_byname, State#state.hosts_byaddr, Names, inet6, IP), {reply, ok, State}; {del_host,{A,B,C,D}=IP} when ?ip(A,B,C,D) -> do_del_host(State#state.hosts_byname, State#state.hosts_byaddr, IP), {reply, ok, State}; {del_host,{A,B,C,D,E,F,G,H}=IP} when ?ip6(A,B,C,D,E,F,G,H) -> do_del_host(State#state.hosts_byname, State#state.hosts_byaddr, 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}; {del_rr, RR} when is_record(RR, dns_rr) -> %% note. del_rr will handle wildcards !!! Cache = State#state.cache, ets:match_delete(Cache, RR), {reply, ok, State}; {lookup_rr, Domain, Class, Type} -> {reply, do_lookup_rr(Domain, Class, Type), State}; {listop, Opt, Op, E} -> El = [E], case res_check_option(Opt, El) of true -> Optname = res_optname(Opt), [{_,Es}] = ets:lookup(Db, Optname), NewEs = case Op of ins -> [E | lists_delete(E, Es)]; add -> lists_delete(E, Es) ++ El; del -> lists_delete(E, Es) end, ets:insert(Db, {Optname, NewEs}), {reply,ok,State}; false -> {reply,error,State} end; {listdel, Opt} -> ets:insert(Db, {res_optname(Opt), []}), {reply, ok, State}; {set_hostname, Name} -> case inet_parse:visible_string(Name) of true -> ets:insert(Db, {hostname, Name}), {reply, ok, State}; false -> {reply, error, State} end; {res_set, hosts_file_name=Option, Fname} -> handle_set_file( Option, Fname, res_hosts_file_tm, res_hosts_file_info, undefined, From, State); {res_set, resolv_conf_name=Option, Fname} -> handle_set_file( Option, Fname, res_resolv_conf_tm, res_resolv_conf_info, undefined, From, State); {res_set, hosts_file=Option, Fname} -> handle_set_file( Option, Fname, res_hosts_file_tm, res_hosts_file_info, fun (Bin) -> case inet_parse:hosts( Fname, {chars,Bin}) of {ok,Opts} -> [{load_hosts_file,Opts}]; _ -> error end end, From, State); %% {res_set, resolv_conf=Option, Fname} -> handle_set_file( Option, Fname, res_resolv_conf_tm, res_resolv_conf_info, fun (Bin) -> case inet_parse:resolv( Fname, {chars,Bin}) of {ok,Opts} -> Search = lists:foldl( fun ({search,L}, _) -> L; ({domain,""}, S) -> S; ({domain,D}, _) -> [D]; (_, S) -> S end, [], Opts), [del_ns, clear_search, clear_cache, {search,Search} |[Opt || {nameserver,_}=Opt <- Opts]]; _ -> error end end, From, State); %% {res_set, Opt, Value} -> case res_optname(Opt) of undefined -> {reply, error, State}; Optname -> case res_check_option(Opt, Value) of true -> ets:insert(Db, {Optname, Value}), {reply, ok, State}; false -> {reply, error, State} end end; {set_resolv_conf_tm, TM} -> ets:insert(Db, {res_resolv_conf_tm, TM}), {reply, ok, State}; {set_hosts_file_tm, TM} -> ets:insert(Db, {res_hosts_file_tm, TM}), {reply, ok, State}; {set_socks_server, {A,B,C,D}} when ?ip(A,B,C,D) -> ets:insert(Db, {socks5_server, {A,B,C,D}}), {reply, ok, State}; {set_socks_port, Port} when is_integer(Port) -> ets:insert(Db, {socks5_port, Port}), {reply, ok, State}; {add_socks_methods, Ls} -> [{_,As}] = ets:lookup(Db, socks5_methods), As1 = lists_subtract(As, Ls), ets:insert(Db, {socks5_methods, As1 ++ Ls}), {reply, ok, State}; {del_socks_methods, Ls} -> [{_,As}] = ets:lookup(Db, socks5_methods), As1 = lists_subtract(As, Ls), case lists:member(none, As1) of false -> ets:insert(Db, {socks5_methods, As1 ++ [none]}); true -> ets:insert(Db, {socks5_methods, As1}) end, {reply, ok, State}; del_socks_methods -> ets:insert(Db, {socks5_methods, [none]}), {reply, ok, State}; {add_socks_noproxy, {{A,B,C,D},{MA,MB,MC,MD}}} when ?ip(A,B,C,D), ?ip(MA,MB,MC,MD) -> [{_,As}] = ets:lookup(Db, socks5_noproxy), ets:insert(Db, {socks5_noproxy, As++[{{A,B,C,D},{MA,MB,MC,MD}}]}), {reply, ok, State}; {del_socks_noproxy, {A,B,C,D}=IP} when ?ip(A,B,C,D) -> [{_,As}] = ets:lookup(Db, socks5_noproxy), ets:insert(Db, {socks5_noproxy, lists_keydelete(IP, 1, As)}), {reply, ok, State}; {set_tcp_module, Mod} when is_atom(Mod) -> ets:insert(Db, {tcp_module, Mod}), %% check/load module ? {reply, ok, State}; {set_udp_module, Mod} when is_atom(Mod) -> ets:insert(Db, {udp_module, Mod}), %% check/load module ? {reply, ok, State}; {set_sctp_module, Fam} when is_atom(Fam) -> ets:insert(Db, {sctp_module, Fam}), %% check/load module ? {reply, ok, State}; {set_cache_size, Size} when is_integer(Size), Size >= 0 -> ets:insert(Db, {cache_size, Size}), {reply, ok, State}; {set_cache_refresh, Time} when is_integer(Time), Time > 0 -> Time1 = ((Time+999) div 1000)*1000, %% round up ets:insert(Db, {cache_refresh_interval, Time1}), _ = stop_timer(State#state.cache_timer), {reply, ok, State#state{cache_timer = init_timer()}}; clear_hosts -> ets:delete_all_objects(State#state.hosts_byname), ets:delete_all_objects(State#state.hosts_byaddr), {reply, ok, State}; clear_cache -> ets:match_delete(State#state.cache, '_'), {reply, ok, State}; reset -> reset_db(Db), _ = stop_timer(State#state.cache_timer), {reply, ok, State#state{cache_timer = init_timer()}}; {add_rc_list, List} -> handle_rc_list(List, From, State); stop -> {stop, normal, ok, State}; _ -> {reply, error, State} end. %%---------------------------------------------------------------------- %% Func: handle_cast/2 %% Returns: {noreply, State} | %% {noreply, State, Timeout} | %% {stop, Reason, State} (terminate/2 is called) %%---------------------------------------------------------------------- -spec handle_cast(term(), state()) -> {'noreply', state()}. handle_cast(_Msg, State) -> {noreply, State}. %%---------------------------------------------------------------------- %% Func: handle_info/2 %% Returns: {noreply, State} | %% {noreply, State, Timeout} | %% {stop, Reason, State} (terminate/2 is called) %%---------------------------------------------------------------------- -spec handle_info(term(), state()) -> {'noreply', state()}. handle_info(refresh_timeout, State) -> do_refresh_cache(State#state.cache), {noreply, State#state{cache_timer = init_timer()}}; handle_info(_Info, State) -> {noreply, State}. %%---------------------------------------------------------------------- %% Func: terminate/2 %% Purpose: Shutdown the server %% Returns: any (ignored by gen_server) %%---------------------------------------------------------------------- -spec terminate(term(), state()) -> 'ok'. terminate(_Reason, State) -> _ = stop_timer(State#state.cache_timer), ok. %%%---------------------------------------------------------------------- %%% Internal functions %%%---------------------------------------------------------------------- handle_set_file(Option, Fname, TagTm, TagInfo, ParseFun, From, #state{db=Db}=State) -> case res_check_option(Option, Fname) of true when Fname =:= "" -> ets:insert(Db, {res_optname(Option), Fname}), ets:delete(Db, TagInfo), ets:delete(Db, TagTm), handle_set_file(ParseFun, <<>>, From, State); true when ParseFun =:= undefined -> File = filename:flatten(Fname), ets:insert(Db, {res_optname(Option), File}), ets:insert(Db, {TagInfo, undefined}), TimeZero = - (?RES_FILE_UPDATE_TM + 1), % Early enough ets:insert(Db, {TagTm, TimeZero}), {reply,ok,State}; true -> File = filename:flatten(Fname), ets:insert(Db, {res_optname(Option), File}), Bin = case erl_prim_loader:read_file_info(File) of {ok, Finfo0} -> Finfo = Finfo0#file_info{access = undefined, atime = undefined}, ets:insert(Db, {TagInfo, Finfo}), ets:insert(Db, {TagTm, times()}), case erl_prim_loader:get_file(File) of {ok, B, _} -> B; _ -> <<>> end; _ -> <<>> end, handle_set_file(ParseFun, Bin, From, State); false -> {reply,error,State} end. handle_set_file(ParseFun, Bin, From, State) -> case ParseFun(Bin) of error -> {reply,error,State}; Opts -> handle_rc_list(Opts, From, State) end. %% Byname has lowercased names while Byaddr keep the name casing. %% This is to be able to reconstruct the original /etc/hosts entry. do_add_host(Byname, Byaddr, Names, Type, IP) -> do_del_host(Byname, Byaddr, IP), ets:insert(Byname, [{tolower(N),Type,IP} || N <- Names]), ets:insert(Byaddr, [{N,Type,IP} || N <- Names]), ok. do_del_host(Byname, Byaddr, IP) -> _ = [ets:delete_object(Byname, {tolower(Name),Type,Addr}) || {Name,Type,Addr} <- ets:lookup(Byaddr, IP)], ets:delete(Byaddr, IP), ok. %% Loop over .inetrc option list and call handle_call/3 for each %% handle_rc_list([], _From, State) -> {reply, ok, State}; handle_rc_list([Opt|Opts], From, State) -> case rc_opt_req(Opt) of undefined -> {reply, {error,{badopt,Opt}}, State}; Req -> case handle_calls(Req, From, State) of {reply, ok, NewState} -> handle_rc_list(Opts, From, NewState); Result -> Result end end; handle_rc_list(_, _From, State) -> {reply, error, State}. handle_calls([], _From, State) -> {reply, ok, State}; handle_calls([Req|Reqs], From, State) -> case handle_call(Req, From, State) of {reply, ok, NewState} -> handle_calls(Reqs, From, NewState); {reply, _, NewState} -> {reply, error, NewState} %% {noreply,_} is currently not returned by handle_call/3 end; handle_calls(Req, From, State) -> handle_call(Req, From, State). %% Translate .inetrc option into gen_server request %% rc_opt_req({nameserver, Ns}) -> {listop,nameservers,add,{Ns,?NAMESERVER_PORT}}; rc_opt_req({nameserver, Ns, Port}) -> {listop,nameservers,add,{Ns,Port}}; rc_opt_req({alt_nameserver, Ns}) -> {listop,alt_nameservers,add,{Ns,?NAMESERVER_PORT}}; rc_opt_req({alt_nameserver, Ns, Port}) -> {listop,alt_nameservers,add,{Ns,Port}}; rc_opt_req({socks5_noproxy, IP, Mask}) -> {add_socks_noproxy, {IP, Mask}}; rc_opt_req({search, Ds}) when is_list(Ds) -> try [{listop,search,add,D} || D <- Ds] catch error:_ -> undefined end; rc_opt_req({host, IP, Aliases}) -> {add_host, IP, Aliases}; rc_opt_req({load_hosts_file, _}=Req) -> Req; rc_opt_req({lookup, Ls}) -> try {res_set, lookup, translate_lookup(Ls)} catch error:_ -> undefined end; rc_opt_req({Name,Arg}) -> case rc_reqname(Name) of undefined -> case is_res_set(Name) of true -> {res_set,Name,Arg}; false -> undefined end; Req -> {Req, Arg} end; rc_opt_req(del_ns) -> {listdel,nameservers}; rc_opt_req(del_alt_ns) -> {listdel,alt_nameservers}; rc_opt_req(clear_ns) -> [{listdel,nameservers},{listdel,alt_nameservers}]; rc_opt_req(clear_search) -> {listdel,search}; rc_opt_req(Opt) when is_atom(Opt) -> case is_reqname(Opt) of true -> Opt; false -> undefined end; rc_opt_req(_) -> undefined. %% rc_reqname(socks5_server) -> set_socks_server; rc_reqname(socks5_port) -> set_socks_port; rc_reqname(socks5_methods) -> set_socks_methods; rc_reqname(cache_refresh) -> set_cache_refresh; rc_reqname(cache_size) -> set_cache_size; rc_reqname(udp) -> set_udp_module; rc_reqname(sctp) -> set_sctp_module; rc_reqname(tcp) -> set_tcp_module; rc_reqname(_) -> undefined. %% is_res_set(domain) -> true; is_res_set(lookup) -> true; is_res_set(timeout) -> true; is_res_set(retry) -> true; is_res_set(inet6) -> true; is_res_set(usevc) -> true; is_res_set(edns) -> true; is_res_set(udp_payload_size) -> true; is_res_set(resolv_conf) -> true; is_res_set(hosts_file) -> true; is_res_set(_) -> false. %% is_reqname(reset) -> true; is_reqname(clear_cache) -> true; is_reqname(clear_hosts) -> true; is_reqname(_) -> false. %% Add a resource record to the cache if there are space left. %% If the cache is full this function first deletes old entries, %% i.e. entries with oldest latest access time. %% #dns_rr.cnt is used to store the access time instead of number of %% accesses. do_add_rr(RR, Db, State) -> CacheDb = State#state.cache, TM = times(), case alloc_entry(Db, CacheDb, TM) of true -> cache_rr(Db, CacheDb, RR#dns_rr{tm = TM, cnt = TM}); _ -> false end. cache_rr(_Db, Cache, RR) -> %% delete possible old entry ets:match_delete(Cache, RR#dns_rr{cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_'}), ets:insert(Cache, RR). times() -> erlang:convert_time_unit(erlang:monotonic_time() - erlang:system_info(start_time),native,seconds). %% lookup and remove old entries do_lookup_rr(Domain, Class, Type) -> match_rr(#dns_rr{domain = tolower(Domain), class = Class,type = Type, cnt = '_', tm = '_', ttl = '_', bm = '_', func = '_', data = '_'}). match_rr(RR) -> filter_rr(ets:match_object(inet_cache, RR), times()). %% filter old resource records and update access count filter_rr([RR | RRs], Time) when RR#dns_rr.ttl =:= 0 -> %% at least once ets:match_delete(inet_cache, RR), [RR | filter_rr(RRs, Time)]; filter_rr([RR | RRs], Time) when RR#dns_rr.tm + RR#dns_rr.ttl < Time -> ets:match_delete(inet_cache, RR), filter_rr(RRs, Time); filter_rr([RR | RRs], Time) -> ets:match_delete(inet_cache, RR), ets:insert(inet_cache, RR#dns_rr { cnt = Time }), [RR | filter_rr(RRs, Time)]; filter_rr([], _Time) -> []. %% Lower case the domain name before storage. %% lower_rr(#dns_rr{domain=Domain}=RR) when is_list(Domain) -> RR#dns_rr { domain = tolower(Domain) }; lower_rr(RR) -> RR. %% %% Case fold upper-case to lower-case according to RFC 4343 %% "Domain Name System (DNS) Case Insensitivity Clarification". %% %% NOTE: this code is in kernel and we don't want to relay %% to much on stdlib. Furthermore string:to_lower/1 %% does not follow RFC 4343. %% tolower([]) -> []; tolower([C|Cs]) when is_integer(C) -> if C >= $A, C =< $Z -> [(C-$A)+$a|tolower(Cs)]; true -> [C|tolower(Cs)] end. 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". 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". dnib(X) -> [hex(X), $., hex(X bsr 4), $., hex(X bsr 8), $., hex(X bsr 12), $.]. hex(X) -> X4 = (X band 16#f), if X4 < 10 -> X4 + $0; true -> (X4-10) + $a end. %% Strip trailing dot, do not produce garbage unless necessary. %% stripdot(Name) -> case stripdot_1(Name) of false -> Name; N -> N end. %% stripdot_1([$.]) -> []; stripdot_1([]) -> false; stripdot_1([H|T]) -> case stripdot_1(T) of false -> false; N -> [H|N] end. %% ------------------------------------------------------------------- %% Refresh cache at regular intervals, i.e. delete expired #dns_rr's. %% ------------------------------------------------------------------- init_timer() -> erlang:send_after(cache_refresh(), self(), refresh_timeout). stop_timer(undefined) -> undefined; stop_timer(Timer) -> erlang:cancel_timer(Timer). cache_refresh() -> case db_get(cache_refresh_interval) of undefined -> ?CACHE_REFRESH; Val -> Val end. %% Delete all entries with expired TTL. %% Returns the access time of the entry with the oldest access time %% in the cache. do_refresh_cache(CacheDb) -> Now = times(), do_refresh_cache(ets:first(CacheDb), CacheDb, Now, Now). do_refresh_cache('$end_of_table', _, _, OldestT) -> OldestT; do_refresh_cache(Key, CacheDb, Now, OldestT) -> Fun = fun(RR, T) when RR#dns_rr.tm + RR#dns_rr.ttl < Now -> ets:match_delete(CacheDb, RR), T; (#dns_rr{cnt = C}, T) when C < T -> C; (_, T) -> T end, Next = ets:next(CacheDb, Key), OldT = lists:foldl(Fun, OldestT, ets:lookup(CacheDb, Key)), do_refresh_cache(Next, CacheDb, Now, OldT). %% ------------------------------------------------------------------- %% Allocate room for a new entry in the cache. %% Deletes entries with expired TTL and all entries with latest %% access time older than %% trunc((TM - OldestTM) * 0.3) + OldestTM from the cache if it %% is full. Does not delete more than 10% of the entries in the cache %% though, unless they there deleted due to expired TTL. %% Returns: true if space for a new entry otherwise false. %% ------------------------------------------------------------------- alloc_entry(Db, CacheDb, TM) -> CurSize = ets:info(CacheDb, size), case ets:lookup(Db, cache_size) of [{cache_size, Size}] when Size =< CurSize, Size > 0 -> alloc_entry(CacheDb, CurSize, TM, trunc(Size * 0.1) + 1); [{cache_size, Size}] when Size =< 0 -> false; _ -> true end. alloc_entry(CacheDb, OldSize, TM, N) -> OldestTM = do_refresh_cache(CacheDb), % Delete timedout entries case ets:info(CacheDb, size) of OldSize -> %% No entrys timedout delete_n_oldest(CacheDb, TM, OldestTM, N); _ -> true end. delete_n_oldest(CacheDb, TM, OldestTM, N) -> DelTM = trunc((TM - OldestTM) * 0.3) + OldestTM, delete_older(CacheDb, DelTM, N) =/= 0. %% Delete entries with latest access time older than TM. %% Delete max N number of entries. %% Returns the number of deleted entries. delete_older(CacheDb, TM, N) -> delete_older(ets:first(CacheDb), CacheDb, TM, N, 0). delete_older('$end_of_table', _, _, _, M) -> M; delete_older(_, _, _, N, M) when N =< M -> M; delete_older(Domain, CacheDb, TM, N, M) -> Next = ets:next(CacheDb, Domain), Fun = fun(RR, MM) when RR#dns_rr.cnt =< TM -> ets:match_delete(CacheDb, RR), MM + 1; (_, MM) -> MM end, M1 = lists:foldl(Fun, M, ets:lookup(CacheDb, Domain)), delete_older(Next, CacheDb, TM, N, M1). %% as lists:delete/2, but delete all exact matches %% lists_delete(_, []) -> []; lists_delete(E, [E|Es]) -> lists_delete(E, Es); lists_delete(E, [X|Es]) -> [X|lists_delete(E, Es)]. %% as '--'/2 aka lists:subtract/2 but delete all exact matches lists_subtract(As0, Bs) -> lists:foldl(fun (E, As) -> lists_delete(E, As) end, As0, Bs). %% as lists:keydelete/3, but delete all _exact_ key matches lists_keydelete(_, _, []) -> []; lists_keydelete(K, N, [T|Ts]) when element(N, T) =:= K -> lists_keydelete(K, N, Ts); lists_keydelete(K, N, [X|Ts]) -> [X|lists_keydelete(K, N, Ts)].