Yonke into obufuna ukuyazi malunga nedilesi ye-MAC

Wonke umntu uyazi ukuba ezi bhayithi zintandathu, zihlala ziboniswa kwifomathi ye-hexadecimal, zinikezelwe kwikhadi lenethiwekhi kumzi-mveliso, kwaye zibonakala zingenamkhethe. Abanye abantu bayazi ukuba ii-byte ezintathu zokuqala zedilesi yi-ID yomenzi, kwaye ii-bytes ezintathu eziseleyo zabelwe zona. Kwaziwa kwakhona ukuba unokuzibeka ngokungenasizathu idilesi. Abantu abaninzi bavile “ngeedilesi ezingaqhelekanga” kwi-Wi-Fi.

Makhe sifumanise ukuba yintoni na.

Idilesi ye-MAC (idilesi yolawulo lokufikelela kwimidiya) sisichongi esikhethekileyo esabelwe i-adapter yenethiwekhi, esetyenziswa kuthungelwano lwemigangatho ye-IEEE 802, ikakhulu i-Ethernet, i-Wi-Fi kunye neBluetooth. Ngokusemthethweni ibizwa ngokuba "yi-EUI-48 uhlobo lokuchonga". Ukususela kwigama kuyacaca ukuba idilesi i-48 bits ubude, okt. iibyte ezi-6. Akukho mgangatho wamkelweyo jikelele wokubhala idilesi (ngokuchaseneyo nedilesi ye-IPv4, apho ii-octets zihlala zohlulwe ngamachaphaza) Ngokuqhelekileyo ibhalwa njengamanani ama-hexadecimal amathandathu ahlulwe ngekholoni: 00:AB:CD:EF:11: 22, nangona abanye abavelisi bezixhobo bakhetha i-notation 00 -AB-CD-EF-11-22 kunye nokuba 00ab.cdef.1122.

Ngokwembali, iidilesi zaye zadanyaza kwi-ROM ye-chipset yekhadi lenethiwekhi ngaphandle kokukwazi ukuziguqula ngaphandle komdwelisi we-flash, kodwa namhlanje idilesi inokutshintshwa ngokucwangcisiweyo kwinkqubo yokusebenza. Unokwenza ngesandla idilesi ye-MAC yekhadi lenethiwekhi kwi-Linux kunye ne-MacOS (rhoqo), iWindows (phantse rhoqo, ukuba umqhubi uvumela), i-Android (ingcambu kuphela); Nge-iOS (ngaphandle kweengcambu) iqhinga elinjalo alinakwenzeka.

Ubume beedilesi

Idilesi inenxalenye yesazisi somenzi, i-OUI, kunye nesazisi esinikwe umenzi. Isabelo se-OUI (Isazisi esahlukileyo kuMbutho) ukuzibandakanya IEEE umbutho. Enyanisweni, ubude bayo bungabi ngama-bytes angama-3 kuphela (ama-24 bits), kodwa i-28 okanye i-36 bits, apho iibhloko (i-Block yedilesi ye-MAC, i-MA) yeedilesi zeentlobo ezinkulu (MA-L), Medium (MA-M) kunye Amancinci akhiwa (MA-S) ngokulandelelana. Ubungakanani bebhloko ekhutshiweyo, kule meko, iya kuba yi-24, 20, 12 bits okanye i-16 yezigidi, i-1 yezigidi, iidilesi ezingamawaka amane. Ngoku kukho malunga nama-4 amawaka eebhloko ezisasaziweyo, zinokujongwa kusetyenziswa izixhobo ezininzi ze-intanethi, umzekelo. IEEE okanye IWireshark.

Ngoobani iidilesi?

Ukusetyenzwa lula kokufumaneka esidlangalaleni ukukhulula ugcino lwedatha IEEE ibonelela ngolwazi oluninzi. Umzekelo, eminye imibutho izithathele iibhloko ezininzi ze-OUI. Nanga amaqhawe ethu:

Umthengisi
Inani leebhloko/iirekhodi
Inani leedilesi, izigidi

Cisco Systems Inc
888
14208

iapile
772
12352

Samsung
636
10144

IHuawei Technologies Co.Ltd
606
9696

Intel Corporation
375
5776

Iqela le-ARRIS INC.
319
5104

INokia Corporation
241
3856

lwaBucala
232
2704

Texas Instruments
212
3392

zte corporation
198
3168

UGunyaziwe woBhaliso we-IEEE
194
3072

Hewlett Packard
149
2384

Hon Hai Precision
136
2176

I-TP-LINK
134
2144

Dell Inc.
123
1968

Inethiwekhi yeJuniper
110
1760

Sagemcom Broadband SAS
97
1552

IFiberhome Telecommunication Technologies Co. LTD
97
1552

UXiaomi Communications Co Ltd
88
1408

Guangdong Oppo Mobile Telecommunications Corp.Ltd
82
1312

UGoogle unama-40 kuphela kubo, kwaye oku akumangalisi: bona ngokwabo abavelisi izixhobo ezininzi zenethiwekhi.

Iibhloko ze-MA azibonelelwanga mahhala, zingathengwa ngexabiso elifanelekileyo (ngaphandle komrhumo wokubhalisa) kwi-$ 3000, i-$ 1800 okanye i-$ 755, ngokulandelanayo. Kuyathakazelisa ukuba imali eyongezelelweyo (ngonyaka) unokuthenga "ukufihla" kolwazi loluntu malunga nebhloko eyabelwe. Ngoku kukho ama-232 kubo, njengoko kunokubonwa ngasentla.

Siza kuphelelwa nini iidilesi ze-MAC?

Sonke sidiniwe ngamabali ebeqhubeka iminyaka eli-10 yokuba "iidilesi ze-IPv4 sele ziza kuphelelwa." Ewe, iibhloko ezintsha ze-IPv4 akusekho lula ukuzifumana. Kuyaziwa ukuba iidilesi ze-IP isasazwe ngokungalinganiyo ngokugqithisileyo; Kukho iibhloko ezinkulu kunye nezingasetyenziswanga kakuhle ezizezamashishini amakhulu kunye neearhente zikarhulumente wase-US, nangona kunjalo, ngethemba elincinci lokuzinikezela kwabo basweleyo. Ukwanda kwe-NAT, CG-NAT kunye ne-IPv6 yenze ukuba ingxaki yokunqongophala kweedilesi zoluntu ingabi mbi kakhulu.

Idilesi ye-MAC inamabhithi angama-48, apho i-46 ingathathwa njenge "luncedo" (kutheni? funda phambili), enika iidilesi ze-246 okanye ze-1014, eziphindwe ngama-214 ngaphezu kwendawo yedilesi ye-IPv4.
Ngoku, malunga nesiqingatha setriliyoni yeedilesi ezisasaziweyo, okanye kuphela i-0.73% yomthamo opheleleyo. Sisekude kakhulu ekuphelelweni ziidilesi ze-MAC.

Amasuntswana angaqhelekanga

Kunokucingelwa ukuba ii-OUIs zisasazwa ngokungacwangciswanga, kwaye umthengisi emva koko ukwabela ngokungenamkhethe iidilesi kwisixhobo sothungelwano ngasinye. Ngaba kunjalo? Makhe sijonge ukuhanjiswa kweebhithi kugcino lweenkcukacha zeedilesi ze-MAC ze-802.11 izixhobo endinazo, eziqokelelwe ziinkqubo zogunyaziso olusebenzayo kwiinethiwekhi ezingenazingcingo. WNAM. Iidilesi zezezixhobo zokwenyani eziqhagamshelwe kwi-Wi-Fi kwiminyaka eliqela kumazwe amathathu. Ukongeza kukho i-database encinci ye-802.3 yezixhobo ze-LAN ezinocingo.

Masicazulule idilesi nganye ye-MAC (iibyte ezintandathu) kwisampulu nganye ibe ngamasuntswana, i-byte nge-byte, kwaye sijonge ukwenzeka rhoqo kwebit ka-“1” kwindawo nganye kwezingama-48. Ukuba i-bit ibekwe ngendlela engafanelekanga ngokupheleleyo, ngoko ke amathuba okufumana "1" kufuneka abe ngama-50%.

Ukukhetha i-Wi-Fi inombolo 1 (RF)
Isampulu ye-Wi-Fi enguNombolo 2 (eBelarus)
Ukukhetha i-Wi-Fi enguNombolo 3 (eUzbekistan)
Iisampulu zeLAN (RF)

Inani leerekhodi kuvimba weenkcukacha
5929000
1274000
366000
1000

Inombolo encinci:
% bit "1"
% bit "1"
% bit "1"
% bit "1"

1
48.6%
49.2%
50.7%
28.7%

2
44.8%
49.1%
47.7%
30.7%

3
46.7%
48.3%
46.8%
35.8%

4
48.0%
48.6%
49.8%
37.1%

5
45.7%
46.9%
47.0%
32.3%

6
46.6%
46.7%
47.8%
27.1%

7
0.3%
0.3%
0.2%
0.7%

8
0.0%
0.0%
0.0%
0.0%

9
48.1%
50.6%
49.4%
38.1%

10
49.1%
50.2%
47.4%
42.7%

11
50.8%
50.0%
50.6%
42.9%

12
49.0%
48.4%
48.2%
53.7%

13
47.6%
47.0%
46.3%
48.5%

14
47.5%
47.4%
51.7%
46.8%

15
48.3%
47.5%
48.7%
46.1%

16
50.6%
50.4%
51.2%
45.3%

17
49.4%
50.4%
54.3%
38.2%

18
49.8%
50.5%
51.5%
51.9%

19
51.6%
53.3%
53.9%
42.6%

20
46.6%
46.1%
45.5%
48.4%

21
51.7%
52.9%
47.7%
48.9%

22
49.2%
49.6%
41.6%
49.8%

23
51.2%
50.9%
47.0%
41.9%

24
49.5%
50.2%
50.1%
47.5%

25
47.1%
47.3%
47.7%
44.2%

26
48.6%
48.6%
49.2%
43.9%

27
49.8%
49.0%
49.7%
48.9%

28
49.3%
49.3%
49.7%
55.1%

29
49.5%
49.4%
49.8%
49.8%

30
49.8%
49.8%
49.7%
52.1%

31
49.5%
49.7%
49.6%
46.6%

32
49.4%
49.7%
49.5%
47.5%

33
49.4%
49.8%
49.7%
48.3%

34
49.7%
50.0%
49.6%
44.9%

35
49.9%
50.0%
50.0%
50.6%

36
49.9%
49.9%
49.8%
49.1%

37
49.8%
50.0%
49.9%
51.4%

38
50.0%
50.0%
49.8%
51.8%

39
49.9%
50.0%
49.9%
55.7%

40
50.0%
50.0%
50.0%
49.5%

41
49.9%
50.0%
49.9%
52.2%

42
50.0%
50.0%
50.0%
53.9%

43
50.1%
50.0%
50.3%
56.1%

44
50.1%
50.0%
50.1%
45.8%

45
50.0%
50.0%
50.1%
50.1%

46
50.0%
50.0%
50.1%
49.5%

47
49.2%
49.4%
49.7%
45.2%

48
49.9%
50.1%
50.7%
54.6%

Kutheni kungekho sikweni ngolu hlobo kwiibhithi ezisi-7 nezisi-8? Phantse kukho ooziro.

Ngokwenene, umgangatho uchaza ezi bits njengezikhethekileyo (Wikipedia):

Eyesibhozo (ukususela ekuqaleni) isuntswana lebyte yokuqala yedilesi yeMAC ibizwa ngokuba yi Unicast/Multicast bit kwaye imisela ukuba loluphi uhlobo lwesakhelo (isakhelo) esihanjiswa ngale dilesi, rhoqo (0) okanye kusasazo (1) (imulticast okanye kusasaza). Ngokwesiqhelo, unxibelelwano lweadaptha yenethiwekhi ye-unicast, le bit imiselwe ku- "0" kuzo zonke iipakethi ezithunyelwe kuyo.

Eyesixhenxe (ukususela ekuqaleni) bit yebyte yokuqala yedilesi ye-MAC ibizwa ngokuba yi-U/L (Universal/Local) bit kwaye imisela ukuba idilesi iyodwa na yehlabathi (0), okanye yodwa ekuhlaleni (1). Ngokungagqibekanga, zonke iidilesi "ezithungelwe ngumenzi" zizodwa kwihlabathi, ngoko ke uninzi lweedilesi eziqokelelweyo ze-MAC ziqulathe iseti yesixhenxe ku-"0". Kwitheyibhile yezazisi ze-OUI ezabelweyo, kuphela malunga namangeno ali-130 ane-U/L bit ye-"1", kwaye ngokucacileyo ezi ziibhloko zeedilesi ze-MAC kwiimfuno ezizodwa.

Ukusuka kweyesithandathu ukuya kweyokuqala ibiyithi yebhayithi yokuqala, amasuntswana ebyte yesibini neyesithathu kwizichazi ze-OUI, kwaye nangakumbi iibits ezikwi-4-6 bytes zedilesi eyabelwe umenzi zisasazwa ngaphezulu okanye ngaphantsi ngokulinganayo. .

Ngaloo ndlela, kwidilesi yokwenyani ye-MAC ye-adapter yenethiwekhi, ii-bits ngokwenene zilingana kwaye azinayo intsingiselo yezobuchwepheshe, ngaphandle kweebhithi ezimbini zenkonzo ye-byte ephezulu.

Indawo yangaphambili

Ngaba uyazibuza ukuba ngabaphi abavelisi bezixhobo ezingenazingcingo zezona zidumileyo? Masidibanise ukukhangela kwi-database ye-OUI kunye nedatha evela kwisampulu yeNombolo ye-1.

Umthengisi
Ukwahlulwa kwezixhobo, %

iapile
26,09

Samsung
19,79

IHuawei Technologies Co. Ltd
7,80

UXiaomi Communications Co Ltd
6,83

Sony Mobile Communications Inc
3,29

I-LG Electronics (uNxibelelwano lweMobile)
2,76

IAustustek IComputer Inc.
2,58

TCT mobile ltd
2,13

zte corporation
2,00

ayifumanekanga kwidatabase ye-IEEE
1,92

Lenovo Mobile Communication Technology Ltd.
1,71

IHTC Corporation
1,68

Murata Manufacturing
1,31

InPro Comm
1,26

Microsoft Corporation
1,11

IShenzhen TINNO Mobile Technology Corp.
1,02

Motorola (Wuhan) Mobility Technologies Communication Co. Ltd.
0,93

INokia Corporation
0,88

IShanghai Wind Technologies Co. Ltd
0,74

Lenovo Mobile Communication (Wuhan) Company Limited
0,71

Uqheliselo lubonisa ukuba okukhona kuphumelela ngakumbi ukubandakanyeka kwababhalisi benethiwekhi engenazingcingo kwindawo ethile, kokukhona isabelo sikhulu sezixhobo ze-Apple.

Ukwahluka

Ngaba iidilesi ze-MAC zodwa? Kwithiyori, ewe, ekubeni umenzi ngamnye wesixhobo (umnini-bhloko we-MA) ufuneka ukuba anike idilesi ekhethekileyo kwi-adapter nganye yenethiwekhi eyivelisayo. Nangona kunjalo, abanye abavelisi be-chip, abanga:

• 00:0A:F5 Airgo Networks, Inc. (ngoku eyiQualcomm)
• 00:08:22 I-InPro Comm (ngoku iMediaTek)

seta iibhayithi ezintathu zokugqibela zedilesi ye-MAC kwinani elingakhethiyo, ngokucacileyo emva kokuba isixhobo ngasinye siqale ngokutsha. Kwakukho iidilesi ezingamawaka angama-1 kwisampulu yam ye-82.

Unako, ngokuqinisekileyo, ukuzibeka idilesi yangaphandle, engeyiyo yodwa ngokuyibeka ngenjongo "njengommelwane wakho", ukuyichonga nge-sniffer, okanye ukuyikhetha ngokungaqhelekanga. Kwakhona kunokwenzeka ukuba uzenzele ngempazamo idilesi engeyiyo yodwa, umzekelo, ukubuyisela ubumbeko logcino lwendlela efana neMikrotik okanye i-OpenWrt.

Kuya kwenzeka ntoni ukuba kukho izixhobo ezibini kwinethiwekhi ezinedilesi efanayo ye-MAC? Konke kuxhomekeke kwingqiqo yezixhobo zenethiwekhi (i-router enentambo, umlawuli wenethiwekhi engenazintambo). Okunokwenzeka, zombini izixhobo aziyi kusebenza okanye ziya kusebenza rhoqo. Ukusuka kwimbono yemigangatho ye-IEEE, ukukhuselwa kwi-spoofing yedilesi ye-MAC kucetywayo ukuba isombululwe kusetyenziswa, umzekelo, i-MACsec okanye i-802.1X.

Kuthekani ukuba ufaka i-MAC nge-bit yesixhenxe okanye yesibhozo kwi-"1", i.e. idilesi yendawo okanye yosasazo oluninzi? Okunokwenzeka ukuba, inethiwekhi yakho ayiyi kuqwalasela oku, kodwa ngokusemthethweni idilesi enjalo ayiyi kuhambelana nomgangatho, kwaye kungcono ukuba ungenzi njalo.

Isebenza njani i-randomization

Siyazi ukuba ukunqanda ukulandelwa kweentshukumo zabantu ngokuskena kunye nokuqokelela amaza omoya, iinkqubo zokusebenza ze-MAC ze-smartphone bezisoloko zisebenzisa itekhnoloji ye-randomization iminyaka eliqela. Ngokwethiyori, xa uskena amaza omoya kukhangelo lweenethiwekhi ezaziwayo, i-smartphone ithumela ipakethi (iqela leepakethi) yohlobo lwesicelo se-802.11 kunye nedilesi ye-MAC njengomthombo:

Ukwenziwa kwe-randomization kukuvumela ukuba ukhankanye “eyathungwayo” enye, kodwa enye idilesi yomthombo wepakethi, itshintsha kumjikelo ngamnye wokuskena, ekuhambeni kwexesha, okanye ngenye indlela. Ngaba iyasebenza? Makhe sijonge izibalo zeedilesi ze-MAC eziqokelelwe emoyeni ngento ebizwa ngokuba yi "Wi-Fi Radar":

Isampulu iyonke
Isampulu kuphela ngo-zero 7th bit

Inani leerekhodi kuvimba weenkcukacha
3920000
305000

Inombolo encinci:
% bit "1"
% bit "1"

1
66.1%
43.3%

2
66.5%
43.4%

3
31.7%
43.8%

4
66.6%
46.4%

5
66.7%
45.7%

6
31.9%
46.4%

7
92.2%
0.0%

8
0.0%
0.0%

9
67.2%
47.5%

10
32.3%
45.6%

11
66.9%
45.3%

12
32.3%
46.8%

13
32.6%
50.1%

14
33.0%
56.1%

15
32.5%
45.0%

16
67.2%
48.3%

17
33.2%
56.9%

18
33.3%
56.8%

19
33.3%
56.3%

20
66.8%
43.2%

21
67.0%
46.4%

22
32.6%
50.1%

23
32.9%
51.2%

24
67.6%
52.2%

25
49.8%
47.8%

26
50.0%
50.0%

27
50.0%
50.2%

28
50.0%
49.8%

29
50.0%
49.4%

30
50.0%
50.0%

31
50.0%
49.7%

32
50.0%
49.9%

33
50.0%
49.7%

34
50.0%
49.6%

35
50.0%
50.1%

36
50.0%
49.5%

37
50.0%
49.9%

38
50.0%
49.8%

39
50.0%
49.9%

40
50.0%
50.1%

41
50.0%
50.2%

42
50.0%
50.2%

43
50.0%
50.1%

44
50.0%
50.1%

45
50.0%
50.0%

46
50.0%
49.8%

47
50.0%
49.8%

48
50.1%
50.9%

Umfanekiso uhluke ngokupheleleyo.

I-8th bit ye-byte yokuqala yedilesi ye-MAC isahambelana nobume be-Unicast yedilesi ye-SRC kwipakethi yesicelo seprobe.

Ibhithi ye-7 imiselwe kwiNdawo kwi-92.2% yamatyala, oko kukuthi. Ngeqondo elifanelekileyo lokuzithemba, sinokucinga ukuba ngokuchanekileyo uninzi lweedilesi eziqokelelweyo azinakwenzeka, kwaye ngaphantsi kwe-8% ziyinyani. Kule meko, unikezelo lweebhithi kwi-OUI kwiidilesi zokwenyani ezinjalo malunga nokuhambelana nedatha kwitheyibhile yangaphambili.

Ngowuphi umenzi, ngokwe-OUI, umnikazi weedilesi ezingahleliwe (oko kukuthi nge-7 bit ku-"1")?

Umvelisi yi-OUI
Yabelana phakathi kwazo zonke iidilesi

ayifumanekanga kwidatabase ye-IEEE
62.45%

Google Inc.
37.54%

phumla
0.01%

Ngaphaya koko, zonke iidilesi ezingakhethi cala ezabelwe uGoogle zeze-OUI enye kunye nesimaphambili DA:A1:19. Yintoni esi simaphambili? Masijonge ngaphakathi Imithombo ye-Android.

private static final MacAddress BASE_GOOGLE_MAC = MacAddress.fromString("da:a1:19:0:0:0");

I-Stock Android isebenzisa i-OUI ekhethekileyo, ebhalisiweyo xa ifuna iinethiwekhi ezingenazintambo, enye yeembalwa ezinesethi yesixhenxe.

Bala i-MAC yokwenyani ukusuka kwi-random enye

Makhe sibone apho:

private static final long VALID_LONG_MASK = (1L << 48) - 1;
private static final long LOCALLY_ASSIGNED_MASK = MacAddress.fromString("2:0:0:0:0:0").mAddr;
private static final long MULTICAST_MASK = MacAddress.fromString("1:0:0:0:0:0").mAddr;

public static @NonNull MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
        long addr;
        if (base == null) {
            addr = r.nextLong() & VALID_LONG_MASK;
        } else {
            addr = (base.mAddr & OUI_MASK) | (NIC_MASK & r.nextLong());
        }
        addr |= LOCALLY_ASSIGNED_MASK;
        addr &= ~MULTICAST_MASK;
        MacAddress mac = new MacAddress(addr);
        if (mac.equals(DEFAULT_MAC_ADDRESS)) {
            return createRandomUnicastAddress(base, r);
        }
        return mac;
    }

Idilesi yonke, okanye iibhayithi zayo ezintathu ezisezantsi, zimsulwa Random.NextLong(). "Ukubuyiswa kobumnini be-MAC yokwenyani" bubuqhophololo. Ngeqondo eliphezulu lokuzithemba, sinokulindela ukuba abavelisi beefowuni ze-Android basebenzise ezinye, ii-OUI ezingabhaliswanga. Asinayo ikhowudi yomthombo we-iOS, kodwa kusenokwenzeka ukuba i-algorithm efanayo iyasetyenziswa apho.

Oku kungasentla akuwurhoxisi umsebenzi wezinye iindlela zokungachazi amagama ababhalisi be-Wi-Fi, ngokusekelwe kuhlalutyo lweminye imimandla yesakhelo sesicelo sophando, okanye ulungelelwaniso lokuphindaphindwa kwezicelo ezithunyelwe sisixhobo. Nangona kunjalo, ukulandelela ngokuthembekileyo umrhumi usebenzisa iindlela zangaphandle kuyingxaki kakhulu. Idatha eqokelelweyo iya kulungeleka ngakumbi ukuhlalutya i-avareji / i-peak load ngendawo kunye nexesha, ngokusekelwe kumanani amakhulu, ngaphandle kokubhekisela kwizixhobo ezithile kunye nabantu. Kuphela abo "ngaphakathi", abavelisi be-OS beselula ngokwabo, kunye nezicelo ezifakiweyo zinedatha echanekileyo.

Yintoni enokuba yingozi malunga nomnye umntu owaziyo idilesi ye-MAC yesixhobo sakho? Ukwala uhlaselo lwenkonzo lunokuqaliswa kwiinethiwekhi ezineengcingo kunye nezingenazingcingo. Kwisixhobo esingenazintambo, ngaphezu koko, ngokunokwenzeka kunokwenzeka ukurekhoda umzuzu wokubonakala kwayo kwindawo apho inzwa ifakwe khona. Ngokubhuqa idilesi, unokuzama "ukwenza ngathi" isixhobo sakho, esinokuthi sisebenze kuphela ukuba akukho manyathelo ongezelelweyo okhuseleko asetyenziswayo (ugunyaziso kunye / okanye ufihlo). I-99.9% yabantu apha abananto yokukhathazeka ngayo.

Idilesi ye-MAC inzima kakhulu kunokuba ibonakala, kodwa ilula kunokuba inokuba njalo.

umthombo: www.habr.com