VPN iyo TURN relay: kee baa dhab ahaan qaada wicitaanka WebRTC?
Tunnel-ku wuxuu beddelaa wadada ICE arko; waligiis ma qoondeeyo relay mana bixiyo signaling. Isbarbar dhig waxa VPN bixinta iyo TURN server kastaa bixiyaan.
Boggu wuxuu ku soo degaa VPN, laakiin wicitaanku waligiis ma xirmaan: laba cilladood oo kala duwan oo isku bar cinwaan ah. Tunnel-ku wuxuu beddelay wadada browser-ku isticmaalo; ma noqon adeeg signaling, STUN server ama relay, mana go'aaminayo labada musharrax ee ICE dooran doono. Kala saarista shaqada qayb kastaa qabato ayaa “WebRTC waa xanniban yahay” mugdiga ah u beddelaysa cillad cad.
Afar shaqo, tunnel-ku wuxuu taabtaa mid keliya
Application-ku wuxuu isdhaafsadaa macluumaadka fadhiga iyada oo loo marayo hab signaling ah, waana shaqada koowaad. ICE waxay ururisaa cinwaannada musharraxiinta oo ay tijaabisaa lammaane ilaa mid shaqeeyo, taasina waa tan labaad. STUN waxay u ogolaataa saaxiib inuu ogaado sida gaadiidkiisu dibadda uga muuqdo, TURN-na waxay u qoondeysaa relay xaaladaha aan jid toos ah jirin. Afartaas door waa kala duwan yihiin, VPN-na waxay saameyn ku leedahay cinwaannada iyo shaandhaynta ay la kulmaan halkii ay mid ka mid ah bixin lahayd.
Sidaas darteed gelitaan guuleysatay waxba kama sheegto wadada media-da. Signaling-ku wuxuu inta badan raacaa isla HTTPS-ka boggu horey u isticmaalo, dekedda 443, halka media-du ay ku socon karto UDP ilaa meel kale oo gebi ahaan ka duwan.
Cinwaannada gaarka ah waxay sii xumeeyaan jahawareerka. Cinwaanka tunnel-ku wuxuu faa'iido u leeyahay saaxiibka kaliya marka uu leeyahay jid ujeeddo leh oo dib ugu noqda; gaar ahaanshuhu ma aha caddeyn ku saabsan gaaritaanka labada dhinac, browsers-kuna sidaas uma tixgeliyaan marka ay tuuraan musharraxiin aan la tijaabin karin. Musharrax u muuqda mid maxalli ah adiga ayaa laga yaabaa in aan laga tijaabin karin dhinaca kale. Farqigaas waa in la tirtiraa ka hor inta aadan go'aansan in tunnel-ku media-da tuurayo.
Isbarbar dhig soo-baxa VPN iyo relay-ga TURN
Labaduba waxay gudbiyaan baakadaha, taasna waa sababta loo khaldo, shaxda isbarbardhigga ee kore waa in loo akhriyaa tiir-tiir halkii liis sifooyin ah. Qoondaynta relay waa shay fadhi kasta oo lagu abuuray codsi la xaqiijiyay; tunnel-ku waa jid. Mid waxay leedahay aqoonsi dhacaya, kan kalena wuxuu leeyahay cinwaan saaxiib oo ama la gaari karo ama aan la gaari karin.
| Component | What it contributes | What it needs to work | What it cannot do |
|---|---|---|---|
| VPN exit | Changes the observed mapping and the route packets take | A working tunnel and a policy that permits the media transport | Allocate a relay or supply signaling |
| STUN server | Reports the mapped address a peer appears to use | Reachability from the client, on its configured transport | Carry media when a direct path fails |
| TURN server | Relays media through an authenticated allocation | Valid credentials, an allowed transport and sufficient capacity | Fix a missing ICE policy or an unauthorized client |
| Signaling channel | Carries offers, answers and candidate lists | Both peers reaching the same application endpoint | Establish connectivity by itself |
Lambarka dekedaha ayaa farqiga ka dhigaya mid la taaban karo. TURN wuxuu caadi ahaan dhageystaa 3478 ee UDP iyo TCP iyo 5349 ee TLS, shabakad ogolaata 443 laakiin tuurta dekedahaas waxay ku guuldareysan doontaa wicitaannada relay-ga ah inta baaritaanku caadi u socdo. Beddelka dekedda VPN waxba kama habeyso taas, sababtoo ah dekedaha muhiimka ah waxaa iska leh adeegga relay, ma aha tunnel-ka.
Akhri ogaanshaha, ka dibna tijaabi wicitaanka
Browsers-ku waxay soo bandhigaan macluumaadka loo baahan yahay iyada oo aan baakad la qaban. Fur bogga ogaanshaha WebRTC ee browser-kaaga, samee wicitaanka, oo akhri lammaanaha musharraxa la doortay halkii liiska la ururiyay: noocyada musharraxa maxalli iyo fog ee la doortay, transport-ka iyo qoyska cinwaanka, iyo in jidku toos yahay ama relay ah.
Laba akhris waa in horey loo ogaadaa. Haddii lammaanaha la doortay uu yahay host-to-host cinwaanno gaar ah, media-du waxay ku sii socotaa jid la sababayn karo; haddii uu yahay relay-to-relay, wicitaanku wuxuu isticmaalaa awoodda relay wuxuuna ku xiran yahay helitaanka adeeggaas. Cillad ku hakata “la hubinayaa” iyada oo aan lammaane la dooran macneheedu waa musharraxiinta la ururiyay laakiin midkoodna ma gudbin hubinta xiriirka.
Ka dib isbarbar dhig labada geesood ee isla wicitaanka iyada oo la beddelayo hal shuruud oo la ansixiyay, oo natiijada ku aqbal media ama xog laba-geesood ah, ma aha tilmaame “xiran”. Ururinta musharraxiinta waxay ku guuleysataa xaalado badan oo aan qaadin hal frame oo cod ah. Ku celi wicitaanka dhinaca kale ee isbeddelka oo kaydi labada qoraal ogaanshaha, sababtoo ah isbarbardhigga laba socod ayaa ka wax badan sheegaya akhriska midkood keliya. Isla geesaha, isla codec-ka, hal doorsoome oo la beddelay.
Application-ku si ula kac ah u dhigayaa siyaasadda transport-ka ICE ee relay waxay dalbanaysaa musharraxiinta relay oo keliya. Dejintaas ma abuurto relay mana hagaajiso aqoonsiga maqan; waxay caddeynaysaa shuruudda, taas oo faa'iido leh marka qof VPN ku eedeeyo siyaasad ay goobtu dooratay.
Hayso sheegashada asturnaanta iyo inta caddayntu ogolaato oo kaliya
Soo-gaadhista musharraxiinta waxay ku xiran tahay siyaasadda browser-ka iyo application-ka, ma aha oo kaliya xaaladda tunnel-ka, oo qeexitaanka W3C ee xiriirka saaxiibka wuxuu u arkaa maaraynta IP arrin u gaar ah. Sidaas darteed VPN xiran waa saldhig daciif ah oo lagu ballan qaadayo in wicitaanku uu daaha ka qaadayo hal cinwaan oo la doortay oo keliya. Xitaa laba saaxiib oo ka dambeeya isla tunnel waxay dooran karaan jid aan waligii ka bixin host-ka, taas oo isku mar ah horumar asturnaanta iyo xaddidid xiriirka.
Waxa si sax ah u sheegi karto waa ka cidhiidhi badan oo ka faa'iido badan: lammaanaha musharraxa ee la doortay, transport-ka qaaday, iyo in jidkaas uu ku sii jiray tunnel-ka gudihiisa. Qor saddexda xaqiiqo wicitaan shaqeeya iyo mid guuldareystay, farqiguna inta badan magacaabaa qaybta la hagaajinayo.
Marka xiriirku shaqeeyo, kala sooc waxqabadka iyo gaaritaanka. Lumis, daahid, saf iyo MTU dhammaantood waxay ka hooseeyaan lammaane musharrax oo sax ah, oo wicitaan googo'an u qaadashada cillad xiriir waxay dib ugu celinaysaa liiska musharraxiinta sabab la'aan.