Likarolo tse fapaneng tsa ts'ebetso ea DNS li se li 'nile tsa angoa khafetsa ke mongoli ka palo ea e hatisitsoeng e le karolo ea blog. Ka nako e ts'oanang, khatiso e kholo e 'nile ea e-ba ho ntlafatsa ts'ireletso ea ts'ebeletso ena ea bohlokoa ea Inthanete.
Ho fihlela morao tjena, ho sa tsotellehe ts'oaetso e totobetseng ea sephethephethe sa DNS, e ntseng e fetisoa ka mokhoa o hlakileng, ho liketso tse lonya ka lehlakoreng la bafani ba batlang ho eketsa chelete ea bona ka ho kenya lipapatso ka litaba, mekhatlo ea ts'ireletso ea 'muso le censorship, hammoho le linokoane feela, ts'ebetso , ho sa tsotellehe boteng ba mekhoa e fapaneng ea theknoloji e kang DNSSEC/DANE, DNScrypt, DNS-over-TLS le DNS-over-HTTPS, e ile ea ema. 'Me haeba litharollo tsa seva,' me tse ling tsa tsona li bile teng ka nako e telele, li tsebahala haholo ebile li fumaneha, tšehetso ea bona ho tsoa ho software ea bareki e siea ho hongata ho sa lokelang.
Ka lehlohonolo, boemo boa fetoha. Haholo-holo, baetsi ba sebatli se tsebahalang sa Firefox mabapi le merero ea ho nolofalletsa mokhoa oa ts'ehetso ka kamehla (DoH) haufinyane. Sena se lokela ho thusa ho sireletsa sephethephethe sa DNS sa mosebelisi oa WWW litšokelong tse kaholimo, empa se ka hlahisa tse ncha.
1. Mathata a DNS-over-HTTPS
Ha u habanya feela, ho hlahisoa ha bongata ba DNS-over-HTTPS ho software ea Marang-rang ho baka karabelo e ntle feela. Leha ho le joalo, diabolose, joalo ka ha ba re, o ka lintlha.
Bothata ba pele bo fokotsang boholo ba tšebeliso e pharalletseng ea DoH ke ho tsepamisa maikutlo ho sephethephethe sa marang-rang feela. Ehlile, HTTP protocol le mofuta oa eona oa hajoale oa HTTP/2, oo DoH e thehiloeng holim'a eona, ke motheo oa WWW. Empa Marang-rang ha se websaete feela. Ho na le lits'ebeletso tse ngata tse tsebahalang, joalo ka lengolo-tsoibila, manqosa a fapaneng a hang-hang, litsamaiso tsa phetisetso ea lifaele, phallo ea multimedia, joalo-joalo, tse sa sebeliseng HTTP. Kahoo, ho sa tsotellehe maikutlo a mangata a DoH e le phekolo, ho bonahala e le ntho e sa sebetseng ntle le boiteko bo eketsehileng (le bo sa hlokahaleng) bakeng sa eng kapa eng ntle le mahlale a sebatli. Ka tsela, DNS-over-TLS e shebahala e le mokhethoa ea tšoanelehang haholoanyane bakeng sa karolo ena, e kenyang ts'ebetso ea sephethephethe sa DNS se tloaelehileng protocol e sireletsehileng ea TLS.
Bothata ba bobeli, boo e ka bang ba bohlokoa ho feta ba pele, ke ho lahloa ha puso ea DNS ka tlhaho molemong oa ho sebelisa seva e le 'ngoe ea DoH e boletsoeng litlhophisong tsa sebatli. Haholo-holo, Mozilla e fana ka maikutlo a ho sebelisa tšebeletso e tsoang ho Cloudflare. Ts'ebeletso e ts'oanang le eona e ile ea qalisoa ke batho ba bang ba hlahelletseng ba Marang-rang, haholo-holo Google. Hoa etsahala hore ts'ebetsong ea DNS-over-HTTPS ka mokhoa oo e reriloeng hona joale e eketsa ho itšetleha ha basebelisi ba ho qetela litšebeletsong tse kholo ka ho fetisisa. Ha se lekunutu hore tlhaiso-leseling eo tlhahlobo ea lipotso tsa DNS e ka fanang ka eona e ka bokella lintlha tse ngata ka eona, hammoho le ho eketsa ho nepahala le bohlokoa ba eona.
Ntlheng ena, mongoli e ne e le motšehetsi oa ts'ebetsong ea bongata eseng ea DNS-over-HTTPS, empa ea DNS-over-TLS hammoho le DNSSEC / DANE e le mokhoa oa bokahohleng, o sireletsehileng le o sa lokelang ho tsoela pele ho kenyelletsa mekhoa ea Inthanete. bakeng sa ho netefatsa polokeho ea sephethephethe sa DNS. Ka bomalimabe, ka mabaka a totobetseng, motho a ke ke a lebella kenyelletso e potlakileng ea tšehetso ea bongata bakeng sa mefuta e meng ea DoH ho software ea bareki, 'me e ntse e le sebaka sa ba chesehelang theknoloji ea ts'ireletso.
Empa kaha joale re na le DoH, ke hobane'ng ha re sa e sebelise ka mor'a ho baleha ho behoa leihlo ke lik'hamphani ka li-server tsa bona ho ea ho seva sa rona sa DNS-over-HTTPS?
2. Protocol ea DNS-over-HTTPS
Haeba u sheba maemo ho hlalosa protocol ea DNS-over-HTTPS, u ka bona hore ha e le hantle, ke API ea websaete e u lumellang hore u kenyelle sephutheloana sa DNS se tloaelehileng ho protocol ea HTTP/2. Sena se sebelisoa ka lihlooho tse khethehileng tsa HTTP, hammoho le phetoho ea sebopeho sa binary sa data e fetisitsoeng ea DNS (bona. le litokomane tse latelang) ka foromo e u lumellang hore u li fetise le ho li amohela, hammoho le ho sebetsa ka metadata e hlokahalang.
Ho latela maemo, ke HTTP/2 feela le khokahano e sireletsehileng ea TLS e tšehetsoeng.
Ho romela kopo ea DNS ho ka etsoa ho sebelisoa mekhoa e tloaelehileng ea GET le POST. Tabeng ea pele, kopo e fetoloa khoele ea base64URL-encoded, 'me ea bobeli, ka' mele oa kopo ea POST ka mokhoa oa binary. Tabeng ena, ho sebelisoa mofuta o khethehileng oa data oa MIME nakong ea kopo le karabo ea DNS application/dns-message.
root@eprove:~ # curl -H 'accept: application/dns-message' 'https://my.domaint/dns-query?dns=q80BAAABAAAAAAAAB2V4YW1wbGUDY29tAAABAAE' -v
* Trying 2001:100:200:300::400:443...
* TCP_NODELAY set
* Connected to eprove.net (2001:100:200:300::400) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /usr/local/share/certs/ca-root-nss.crt
CApath: none
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use h2
* Server certificate:
* subject: CN=my.domain
* start date: Jul 22 00:07:13 2019 GMT
* expire date: Oct 20 00:07:13 2019 GMT
* subjectAltName: host "my.domain" matched cert's "my.domain"
* issuer: C=US; O=Let's Encrypt; CN=Let's Encrypt Authority X3
* SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x801441000)
> GET /dns-query?dns=q80BAAABAAAAAAAAB2V4YW1wbGUDY29tAAABAAE HTTP/2
> Host: eprove.net
> User-Agent: curl/7.65.3
> accept: application/dns-message
>
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* Connection state changed (MAX_CONCURRENT_STREAMS == 100)!
< HTTP/2 200
< server: h2o/2.3.0-beta2
< content-type: application/dns-message
< cache-control: max-age=86274
< date: Thu, 12 Sep 2019 13:07:25 GMT
< strict-transport-security: max-age=15768000; includeSubDomains; preload
< content-length: 45
<
Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.
* Failed writing body (0 != 45)
* stopped the pause stream!
* Connection #0 to host eprove.net left intactHape ela hloko sehlooho Cache-control: karabong e tsoang ho seva sa tepo. Ka parameter lilemo tse ngata e na le boleng ba TTL bakeng sa rekoto ea DNS e khutlisoang (kapa boleng bo tlase haeba sete ea tsona e khutlisoa).
Ho ipapisitsoe le tse kaholimo, ts'ebetso ea seva ea DoH e na le mekhahlelo e mengata.
- Fumana kopo ea HTTP. Haeba sena e le GET, joale khetha pakete ho tloha ho base64URL encoding.
- Romella pakete ena ho seva sa DNS.
- Fumana karabo ho tsoa ho seva sa DNS
- Fumana bonyane ba boleng ba TTL lirekotong tse amohetsoeng.
- Khutlisa karabo ho moreki ka HTTP.
3. Seva ea hau ea DNS-over-HTTPS
Mokhoa o bonolo, o potlakileng le o sebetsang oa ho tsamaisa seva ea hau ea DNS-over-HTTPS ke ho sebelisa HTTP/2 web server. , eo mongoli a seng a ngotse ka eona hakhutšoanyane (sheba “").
Khetho ena e tšehetsoa ke taba ea hore khoutu eohle ea seva sa hau sa DoH e ka kenngoa ts'ebetsong ka botlalo ho sebelisa toloko e kopantsoeng le H2O ka boeona. . Ntle le lilaebrari tse tloaelehileng, ho fapanyetsana data le seva sa DNS, u hloka (mrbgem) laebrari ea Socket, eo, ka lehlohonolo, e seng e kenyelelitsoe phetolelong ea morao-rao ea H2O 2.3.0-beta2 likoung tsa FreeBSD. Leha ho le joalo, ha ho thata ho e kenyelletsa ho mofuta ofe kapa ofe o fetileng ka ho kopanya polokelo ho lethathamong la libuka /deps pele ho kopanngoa.
root@beta:~ # uname -v
FreeBSD 12.0-RELEASE-p10 GENERIC
root@beta:~ # cd /usr/ports/www/h2o
root@beta:/usr/ports/www/h2o # make extract
===> License MIT BSD2CLAUSE accepted by the user
===> h2o-2.2.6 depends on file: /usr/local/sbin/pkg - found
===> Fetching all distfiles required by h2o-2.2.6 for building
===> Extracting for h2o-2.2.6.
=> SHA256 Checksum OK for h2o-h2o-v2.2.6_GH0.tar.gz.
===> h2o-2.2.6 depends on file: /usr/local/bin/ruby26 - found
root@beta:/usr/ports/www/h2o # cd work/h2o-2.2.6/deps/
root@beta:/usr/ports/www/h2o/work/h2o-2.2.6/deps # git clone https://github.com/iij/mruby-socket.git
Клонирование в «mruby-socket»…
remote: Enumerating objects: 385, done.
remote: Total 385 (delta 0), reused 0 (delta 0), pack-reused 385
Получение объектов: 100% (385/385), 98.02 KiB | 647.00 KiB/s, готово.
Определение изменений: 100% (208/208), готово.
root@beta:/usr/ports/www/h2o/work/h2o-2.2.6/deps # ll
total 181
drwxr-xr-x 9 root wheel 18 12 авг. 16:09 brotli/
drwxr-xr-x 2 root wheel 4 12 авг. 16:09 cloexec/
drwxr-xr-x 2 root wheel 5 12 авг. 16:09 golombset/
drwxr-xr-x 4 root wheel 35 12 авг. 16:09 klib/
drwxr-xr-x 2 root wheel 5 12 авг. 16:09 libgkc/
drwxr-xr-x 4 root wheel 26 12 авг. 16:09 libyrmcds/
drwxr-xr-x 13 root wheel 32 12 авг. 16:09 mruby/
drwxr-xr-x 5 root wheel 11 12 авг. 16:09 mruby-digest/
drwxr-xr-x 5 root wheel 10 12 авг. 16:09 mruby-dir/
drwxr-xr-x 5 root wheel 10 12 авг. 16:09 mruby-env/
drwxr-xr-x 4 root wheel 9 12 авг. 16:09 mruby-errno/
drwxr-xr-x 5 root wheel 14 12 авг. 16:09 mruby-file-stat/
drwxr-xr-x 5 root wheel 10 12 авг. 16:09 mruby-iijson/
drwxr-xr-x 5 root wheel 11 12 авг. 16:09 mruby-input-stream/
drwxr-xr-x 6 root wheel 11 12 авг. 16:09 mruby-io/
drwxr-xr-x 5 root wheel 10 12 авг. 16:09 mruby-onig-regexp/
drwxr-xr-x 4 root wheel 10 12 авг. 16:09 mruby-pack/
drwxr-xr-x 5 root wheel 10 12 авг. 16:09 mruby-require/
drwxr-xr-x 6 root wheel 10 12 сент. 16:10 mruby-socket/
drwxr-xr-x 2 root wheel 9 12 авг. 16:09 neverbleed/
drwxr-xr-x 2 root wheel 13 12 авг. 16:09 picohttpparser/
drwxr-xr-x 2 root wheel 4 12 авг. 16:09 picotest/
drwxr-xr-x 9 root wheel 16 12 авг. 16:09 picotls/
drwxr-xr-x 4 root wheel 8 12 авг. 16:09 ssl-conservatory/
drwxr-xr-x 8 root wheel 18 12 авг. 16:09 yaml/
drwxr-xr-x 2 root wheel 8 12 авг. 16:09 yoml/
root@beta:/usr/ports/www/h2o/work/h2o-2.2.6/deps # cd ../../..
root@beta:/usr/ports/www/h2o # make install clean
...Tokiso ea seva ea webo hangata e tloaelehile.
root@beta:/usr/ports/www/h2o # cd /usr/local/etc/h2o/
root@beta:/usr/local/etc/h2o # cat h2o.conf
# this sample config gives you a feel for how h2o can be used
# and a high-security configuration for TLS and HTTP headers
# see https://h2o.examp1e.net/ for detailed documentation
# and h2o --help for command-line options and settings
# v.20180207 (c)2018 by Max Kostikov http://kostikov.co e-mail: [email protected]
user: www
pid-file: /var/run/h2o.pid
access-log:
path: /var/log/h2o/h2o-access.log
format: "%h %v %l %u %t "%r" %s %b "%{Referer}i" "%{User-agent}i""
error-log: /var/log/h2o/h2o-error.log
expires: off
compress: on
file.dirlisting: off
file.send-compressed: on
file.index: [ 'index.html', 'index.php' ]
listen:
port: 80
listen:
port: 443
ssl:
cipher-suite: ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS
cipher-preference: server
dh-file: /etc/ssl/dhparams.pem
certificate-file: /usr/local/etc/letsencrypt/live/eprove.net/fullchain.pem
key-file: /usr/local/etc/letsencrypt/live/my.domain/privkey.pem
hosts:
"*.my.domain":
paths: &go_tls
"/":
redirect:
status: 301
url: https://my.domain/
"my.domain:80":
paths: *go_tls
"my.domain:443":
header.add: "Strict-Transport-Security: max-age=15768000; includeSubDomains; preload"
paths:
"/dns-query":
mruby.handler-file: /usr/local/etc/h2o/h2odoh.rbMokhelo feela ke sebatli sa URL /dns-query eo seva ea rona ea DNS-over-HTTPS, e ngotsoeng ka mruby mme e bitsoa ka khetho ea mohlokomeli, e hlile e ikarabella. mruby.motshwari-faele.
root@beta:/usr/local/etc/h2o # cat h2odoh.rb
# H2O HTTP/2 web server as DNS-over-HTTP service
# v.20190908 (c)2018-2019 Max Kostikov https://kostikov.co e-mail: [email protected]
proc {|env|
if env['HTTP_ACCEPT'] == "application/dns-message"
case env['REQUEST_METHOD']
when "GET"
req = env['QUERY_STRING'].gsub(/^dns=/,'')
# base64URL decode
req = req.tr("-_", "+/")
if !req.end_with?("=") && req.length % 4 != 0
req = req.ljust((req.length + 3) & ~3, "=")
end
req = req.unpack1("m")
when "POST"
req = env['rack.input'].read
else
req = ""
end
if req.empty?
[400, { 'content-type' => 'text/plain' }, [ "Bad Request" ]]
else
# --- ask DNS server
sock = UDPSocket.new
sock.connect("localhost", 53)
sock.send(req, 0)
str = sock.recv(4096)
sock.close
# --- find lowest TTL in response
nans = str[6, 2].unpack1('n') # number of answers
if nans > 0 # no DNS failure
shift = 12
ttl = 0
while nans > 0
# process domain name compression
if str[shift].unpack1("C") < 192
shift = str.index("x00", shift) + 5
if ttl == 0 # skip question section
next
end
end
shift += 6
curttl = str[shift, 4].unpack1('N')
shift += str[shift + 4, 2].unpack1('n') + 6 # responce data size
if ttl == 0 or ttl > curttl
ttl = curttl
end
nans -= 1
end
cc = 'max-age=' + ttl.to_s
else
cc = 'no-cache'
end
[200, { 'content-type' => 'application/dns-message', 'content-length' => str.size, 'cache-control' => cc }, [ str ] ]
end
else
[415, { 'content-type' => 'text/plain' }, [ "Unsupported Media Type" ]]
end
}Ka kopo hlokomela hore seva sa caching sa lehae se ikarabella bakeng sa ho sebetsana le lipakete tsa DNS, tabeng ena ho tsoa ho kabo e tloaelehileng ea FreeBSD. Ho latela pono ea ts'ireletso, ena ke eona tharollo e nepahetseng. Leha ho le joalo, ha ho letho le u thibelang ho nka sebaka Localhost ho atereseng e fapaneng ea DNS eo u ikemiselitseng ho e sebelisa.
root@beta:/usr/local/etc/h2o # local-unbound verison
usage: local-unbound [options]
start unbound daemon DNS resolver.
-h this help
-c file config file to read instead of /var/unbound/unbound.conf
file format is described in unbound.conf(5).
-d do not fork into the background.
-p do not create a pidfile.
-v verbose (more times to increase verbosity)
Version 1.8.1
linked libs: mini-event internal (it uses select), OpenSSL 1.1.1a-freebsd 20 Nov 2018
linked modules: dns64 respip validator iterator
BSD licensed, see LICENSE in source package for details.
Report bugs to [email protected]
root@eprove:/usr/local/etc/h2o # sockstat -46 | grep unbound
unbound local-unbo 69749 3 udp6 ::1:53 *:*
unbound local-unbo 69749 4 tcp6 ::1:53 *:*
unbound local-unbo 69749 5 udp4 127.0.0.1:53 *:*
unbound local-unbo 69749 6 tcp4 127.0.0.1:53 *:*Sohle se setseng ke ho qala H2O bocha le ho bona hore na ho tla eng ka eona.
root@beta:/usr/local/etc/h2o # service h2o restart
Stopping h2o.
Waiting for PIDS: 69871.
Starting h2o.
start_server (pid:70532) starting now...4. Teko
Kahoo, a re hlahlobeng liphetho ka ho romela kopo ea teko hape le ho sheba sephethephethe sa marang-rang se sebelisang thuso tcpdump.
root@beta/usr/local/etc/h2o # curl -H 'accept: application/dns-message' 'https://my.domain/dns-query?dns=q80BAAABAAAAAAAAB2V4YW1wbGUDY29tAAABAAE'
Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.
...
root@beta:~ # tcpdump -n -i lo0 udp port 53 -xx -XX -vv
tcpdump: listening on lo0, link-type NULL (BSD loopback), capture size 262144 bytes
16:32:40.420831 IP (tos 0x0, ttl 64, id 37575, offset 0, flags [none], proto UDP (17), length 57, bad cksum 0 (->e9ea)!)
127.0.0.1.21070 > 127.0.0.1.53: [bad udp cksum 0xfe38 -> 0x33e3!] 43981+ A? example.com. (29)
0x0000: 0200 0000 4500 0039 92c7 0000 4011 0000 ....E..9....@...
0x0010: 7f00 0001 7f00 0001 524e 0035 0025 fe38 ........RN.5.%.8
0x0020: abcd 0100 0001 0000 0000 0000 0765 7861 .............exa
0x0030: 6d70 6c65 0363 6f6d 0000 0100 01 mple.com.....
16:32:40.796507 IP (tos 0x0, ttl 64, id 37590, offset 0, flags [none], proto UDP (17), length 73, bad cksum 0 (->e9cb)!)
127.0.0.1.53 > 127.0.0.1.21070: [bad udp cksum 0xfe48 -> 0x43fa!] 43981 q: A? example.com. 1/0/0 example.com. A 93.184.216.34 (45)
0x0000: 0200 0000 4500 0049 92d6 0000 4011 0000 ....E..I....@...
0x0010: 7f00 0001 7f00 0001 0035 524e 0035 fe48 .........5RN.5.H
0x0020: abcd 8180 0001 0001 0000 0000 0765 7861 .............exa
0x0030: 6d70 6c65 0363 6f6d 0000 0100 01c0 0c00 mple.com........
0x0040: 0100 0100 0151 8000 045d b8d8 22 .....Q...].."
^C
2 packets captured
23 packets received by filter
0 packets dropped by kernelSephetho se bontša kamoo kopo ea ho rarolla aterese mohlala.com e amohetsoe mme ea sebetsoa ka katleho ke seva sa DNS.
Hona joale se setseng ke ho kenya seva ea rona ho sebatli sa Firefox. Ho etsa sena, o hloka ho fetola litlhophiso tse 'maloa maqepheng a tlhophiso mabapi le: config.
Taba ea pele, ena ke aterese ea API ea rona moo sebatli se tla kopa tlhahisoleseling ea DNS ho eona marangrang.trr.uri. E boetse e khothaletsoa ho hlakisa domain name IP ho tsoa ho URL ena bakeng sa tharollo e sireletsehileng ea IP u sebelisa sebatli ka bosona ntle le ho kena ho DNS network.trr.bootstrapAddress. 'Me qetellong, parameter ka boeona network.trr.mode ho kenyeletsa le tshebediso ya DoH. Ho beha boleng ho "3" ho tla qobella sebatli ho sebelisa DNS-over-HTTPS feela bakeng sa ho rarolla mabitso, athe "2" e tšepahalang le e sireletsehileng haholoanyane e tla etelletsa pele DoH, e siea tlhahlobo e tloaelehileng ea DNS e le khetho e ka morao.
5. MOLEMO!
Na sehlooho see se thusitse? Joale ka kopo u se ke ua ba lihlong le ho tšehetsa ka chelete ka foromo ea monehelo (ka tlase).
Source: www.habr.com