Konke obufuna ukukwazi mayelana nekheli le-MAC

Wonke umuntu uyazi ukuthi lawa mabhayithi ayisithupha, ngokuvamile aboniswa ngefomethi ye-hexadecimal, anikezwa ekhadini lenethiwekhi efektri, futhi abonakala ngokungahleliwe. Abanye abantu bayazi ukuthi amabhayithi amathathu okuqala ekheli ayi-ID yomkhiqizi, futhi amabhayithi amathathu asele abelwa wona. Kuyaziwa futhi ukuthi ungazibekela wena ngokunganaki ikheli. Abantu abaningi bezwe “ngamakheli angahleliwe” ku-Wi-Fi.

Ake sithole ukuthi kuyini.

Ikheli le-MAC (ikheli lokulawula ukufinyelela kwemidiya) liyisihlonzi esiyingqayizivele esinikezwe i-adaptha yenethiwekhi, esetshenziswa kumanethiwekhi wamazinga we-IEEE 802, ikakhulukazi i-Ethernet, i-Wi-Fi ne-Bluetooth. Ngokusemthethweni ibizwa ngokuthi "isihlonzi sohlobo lwe-EUI-48". Kusukela egameni kusobala ukuthi ikheli liyi-48 bits ubude, i.e. 6 amabhayithi. Alikho izinga elijwayelekile elamukelwayo lokubhala ikheli (ngokungafani nekheli le-IPv4, lapho ama-octet ehlala ehlukaniswa ngamachashazi). Ngokuvamile libhalwa njengezinombolo ze-hexadecimal eziyisithupha ezihlukaniswa ikholoni: 00:AB:CD:EF:11: 22, nakuba abanye abakhiqizi bemishini bekhetha i-notation 00 -AB-CD-EF-11-22 ngisho 00ab.cdef.1122.

Ngokomlando, amakheli ayefakwe ku-chipset ROM yekhadi lenethiwekhi futhi ayengenakushintshwa ngaphandle kohlelo lwe-flash, kodwa kulezi zinsuku ikheli lingashintshwa ngokohlelo kusuka ohlelweni lokusebenza. Ungazisetha ngesandla ikheli le-MAC lekhadi lenethiwekhi ku Linux kanye ne-MacOS (njalo), Windows (cishe njalo, uma umshayeli evuma), Android (kusekelwe kuphela); nge-iOS (ngaphandle kwempande) icebo elinjalo alinakwenzeka.

Isakhiwo sekheli

Ikheli liqukethe ingxenye yesihlonzi somkhiqizi, i-OUI, kanye nesihlonzi esinikezwe umenzi. Izihlonzi Zomsebenzi Wokunikezwa kwe-OUI (Izihlonzi Eziyingqayizivele Yenhlangano). wazibandakanya IEEE inhlangano. Eqinisweni, ubude bayo abukwazi ukuba ngamabhayithi angu-3 kuphela (amabhithi angu-24), kodwa amabhithi angama-28 noma angu-36, okuvimba kuwo amakheli ezinhlobo Ezinkulu (MA-L), Medium (MA-M) kanye ne-MAC Address Block. Amancane akhiwa (MA-S) ngokulandelana. Ubukhulu bebhulokhi ekhishiwe, kulokhu, kuzoba yi-24, 20, 12 bits noma izigidi ezingu-16, izigidi ezingu-1, amakheli angu-4 ayizinkulungwane. Okwamanje kunamabhulokhi angaba yizinkulungwane ezingama-38 asabalalisiwe, angabukwa kusetshenziswa amathuluzi amaningi aku-inthanethi, isibonelo. IEEE noma I-Wireshark.

Ubani umnikazi wamakheli?

Ukucubungula okulula okutholakala esidlangalaleni ukulayisha imininingwane I-IEEE inikeza ulwazi oluningi impela. Isibonelo, ezinye izinhlangano zizithathele amabhulokhi amaningi e-OUI. Nanka amaqhawe ethu:

Umthengisi
Inani lamabhulokhi/amarekhodi
Inombolo yamakheli, isigidi

I-Cisco Systems Inc
888
14208

Apple
772
12352

Samsung
636
10144

IHuawei Technologies Co.Ltd
606
9696

Intel Corporation
375
5776

Inkampani ARRIS Group Inc.
319
5104

INokia Corporation
241
3856

Private
232
2704

Texas Instruments
212
3392

Inkampani yezte
198
3168

I-IEEE Registration Authority
194
3072

Hewlett Packard
149
2384

Hon Hai Precision
136
2176

TP-LINK
134
2144

I-Dell Inc.
123
1968

Amanethiwekhi weJuniper
110
1760

I-Sagemcom Broadband SAS
97
1552

Inkampani Fiberhome Telecommunication Technologies Co., Ltd. LTD
97
1552

Inkampani Xiaomi Communications Co., Ltd
88
1408

I-Guangdong Oppo Mobile Telecommunications Corp.Ltd
82
1312

I-Google inama-40 kuphela kubo, futhi lokhu akumangazi: bona ngokwabo abakhiqizi amadivaysi amaningi enethiwekhi.

Amabhulokhi e-MA awanikezwa mahhala, angathengwa ngentengo efanelekile (ngaphandle kwenkokhelo yokubhalisa) nge-$ 3000, $ 1800 noma i-$ 755, ngokulandelanayo. Kuyathakazelisa ukuthi ngemali eyengeziwe (ngonyaka) ungathenga "ukufihla" kolwazi lomphakathi mayelana ne-block eyabiwe. Manje kunama-232 awo, njengoba kubonakala ngenhla.

Sizophelelwa nini amakheli e-MAC?

Sonke sikhathele yizindaba eseziqhubeke iminyaka eyi-10 zokuthi "amakheli e-IPv4 asezophela." Yebo, amabhulokhi amasha e-IPv4 akusatholakali kalula. Kuyaziwa ukuthi amakheli e-IP kusatshalaliswa ngokungalingani kakhulu; Kunamabhulokhi amakhulu futhi angasetshenziswa kancane aphethwe yizinkampani ezinkulu kanye nezinhlaka zikahulumeni wase-US, nokho, anethemba elincane lokuwasakaza kabusha kulabo abadinga usizo. Ukwanda kwe-NAT, CG-NAT kanye ne-IPv6 kwenze inkinga yokushoda kwamakheli omphakathi yancipha kakhulu.

Ikheli le-MAC linamabhithi angu-48, okungama-46 angabhekwa “njengosizo” (kungani? funda kuqhubeke), elinikeza amakheli angu-246 noma angu-1014, okuphindwe izikhathi ezingu-214 kunesikhala sekheli le-IPv4.
Njengamanje, cishe isigamu sesigidigidi samakheli asabalalisiwe, noma kuphela u-0.73% wevolumu iyonke. Sisekude kakhulu nokuphelelwa amakheli e-MAC.

Izingcezu ezingahleliwe

Kungacatshangwa ukuthi ama-OUI asakazwa ngokungahleliwe, futhi umthengisi aphinde anikeze ngokungahleliwe amakheli kumadivayisi enethiwekhi angawodwana. Ingabe kunjalo? Ake sibheke ukusatshalaliswa kwamabhithi kusizindalwazi samakheli e-MAC wamadivayisi angu-802.11 enginawo, aqoqwe amasistimu okugunyaza asebenzayo kumanethiwekhi angenantambo. WNAM. Amakheli angawamadivayisi angempela axhumeke ku-Wi-Fi eminyakeni embalwa emazweni amathathu. Ngaphezu kwalokho kukhona isizindalwazi esincane samadivayisi we-LAN anezintambo angu-802.3.

Ake sihlukanise ikheli le-MAC ngalinye (amabhayithi ayisithupha) esampula ngalinye libe amabhithi, ibhayithi ngebhayithi, futhi sibheke imvamisa yokwenzeka kwebhithi ethi “1” endaweni ngayinye kwezingu-48. Uma ibhithi isethwe ngendlela engafanele, khona-ke amathuba okuthola "1" kufanele abe ngu-50%.

Ukukhetha i-Wi-Fi No. 1 (RF)
Isampula ye-Wi-Fi No. 2 (Belarus)
Ukukhetha i-Wi-Fi No. 3 (Uzbekistan)
Isampula ye-LAN (RF)

Inombolo yamarekhodi kusizindalwazi
5929000
1274000
366000
1000

Inombolo encane:
% 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%

Kungani ukungabi nabulungisa okungaka ku-7 no-8 bits? Cishe njalo kukhona oziro.

Ngempela, indinganiso ichaza lezi zingcezu njengezikhethekile (I-Wikipedia):

Ibhithi yesishiyagalombili (kusukela ekuqaleni) yebhayithi yokuqala yekheli le-MAC ibizwa ngokuthi i-Unicast/Multicast bit futhi inquma ukuthi hlobo luni lohlaka (uhlaka) oluthunyelwa ngaleli kheli, elivamile (0) noma elisakazwayo (1) (i-multicast noma ukusakaza). Ekuxhumaneni okuvamile, kwe-adaptha yenethiwekhi ye-unicast, le bitana isethwe ukuze ithi “0” kuwo wonke amaphakethe athunyelwe kuyo.

Ibhithi yesikhombisa (kusukela ekuqaleni) yebhayithi yokuqala yekheli le-MAC ibizwa nge-U/L (Universal/Local) bit futhi inquma ukuthi ikheli lihlukile yini emhlabeni wonke (0), noma lihlukile endaweni (1). Ngokuzenzakalelayo, wonke amakheli “athungelwe umkhiqizi” ahlukile emhlabeni wonke, ngakho-ke iningi lamakheli e-MAC aqoqiwe aqukethe ibhithi yesikhombisa ebekwe ku-“0”. Kuthebula lezihlonzi ze-OUI ezinikeziwe, cishe okufakiwe okungu-130 kuphela okune-U/L bit "1", futhi ngokusobala lawa amabhulokhi amakheli e-MAC ezidingo ezikhethekile.

Kusukela kwesithupha kuya kweyokuqala yebhayithi yokuqala, amabhithi ebhayithi yesibili neyesithathu kuzihlonzi ze-OUI, futhi ngisho nangaphezulu amabhithi akubhayithi angu-4-6 ekheli elinikezwe umenzi asakazwa ngokulinganayo noma kancane ngokulinganayo. .

Ngakho, ekhelini langempela le-MAC le-adaptha yenethiwekhi, izingcezu ziyalingana futhi azinayo incazelo yezobuchwepheshe, ngaphandle kwezingcezu ezimbili zesevisi ye-byte ephezulu.

Ukuvama

Uyazibuza ukuthi yibaphi abakhiqizi bemishini engenantambo abadume kakhulu? Masihlanganise ukusesha kusizindalwazi se-OUI nedatha evela kusampula No. 1.

Umthengisi
Ukwabelana ngamadivayisi, %

Apple
26,09

Samsung
19,79

IHuawei Technologies Co. Ltd
7,80

Inkampani Xiaomi Communications Co., Ltd
6,83

I-Sony Mobile Communications Inc
3,29

I-LG Electronics (Ezokuxhumana Ngeselula)
2,76

Inkampani ASUSTek COMPUTER INC.
2,58

Inkampani TCT Mobile Ltd
2,13

Inkampani yezte
2,00

ayitholakali kusizindalwazi se-IEEE
1,92

Lenovo Mobile Communication Technology Ltd.
1,71

I-HTC Corporation
1,68

I-Murata Manufacturing
1,31

I-InPro Comm
1,26

Microsoft Corporation
1,11

Inkampani Shenzhen TINNO Mobile Technology Corp.
1,02

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

INokia Corporation
0,88

Inkampani ye-Shanghai Wind Technologies Co. Ltd
0,74

I-Lenovo Mobile Communication (Wuhan) Company Limited
0,71

Ukuzijwayeza kukhombisa ukuthi lapho kuchume kakhulu inani lababhalisi benethiwekhi engenantambo endaweni ethile, kuba sikhulu isabelo samadivayisi we-Apple.

Okuhlukile

Ingabe amakheli e-MAC ahlukile? Ngokombono, yebo, njengoba umkhiqizi wedivayisi ngayinye (umnikazi we-block ye-MA) kudingeka ukuthi anikeze ikheli eliyingqayizivele ku-adaptha yenethiwekhi ngayinye eyikhiqizayo. Nokho, abanye abakhiqizi be-chip, okungukuthi:

• 00:0A:F5 Airgo Networks, Inc. (manje i-Qualcomm)
• 00:08:22 I-InPro Comm (manje i-MediaTek)

setha amabhayithi amathathu okugcina ekheli le-MAC enombolweni engahleliwe, ngokusobala ngemva kokuqalisa kabusha idivayisi ngayinye. Kwakukhona amakheli anjalo ayizinkulungwane ezingu-1 kusampula yami No.

Yebo, ungazibekela ikheli lakwelinye izwe, elingelona elehlukile ngokulimisa ngamabomu “njengelikamakhelwane wakho”, ulihlonze ngomuntu ohogelayo, noma ulikhethe ngokungahleliwe. Kungenzeka futhi ukuthi ngephutha uzibekele ikheli elingelona elehlukile, ngokwesibonelo, ukubuyisela ukucushwa kwekhophi yasenqolobaneni yomzila njenge-Mikrotik noma i-OpenWrt.

Kuzokwenzekani uma kunamadivayisi amabili kunethiwekhi anekheli elifanayo le-MAC? Konke kuncike ku-logic yemishini yenethiwekhi (irutha enezintambo, isilawuli senethiwekhi engenantambo). Ngokunokwenzeka, womabili amadivaysi ngeke asebenze noma azosebenza ngezikhathi ezithile. Ngokombono wamazinga e-IEEE, ukuvikelwa ekuphangeni kwekheli le-MAC kuhlongozwa ukuthi kuxazululwe kusetshenziswa, isibonelo, i-MACsec noma i-802.1X.

Kuthiwani uma ufaka i-MAC ngebhithi yesikhombisa noma yesishiyagalombili isethwe ku-“1”, i.e. ikheli lendawo noma lokusakaza okuningi? Cishe, inethiwekhi yakho ngeke ikunake lokhu, kodwa ngokusemthethweni ikheli elinjalo ngeke lihambisane nesilinganiso, futhi kungcono ukungenzi kanjalo.

Indlela i-randomization isebenza ngayo

Siyazi ukuthi ukuze kuvinjelwe ukulandelela ukunyakaza kwabantu ngokuskena nokuqoqa amaza omoya, izinhlelo zokusebenza ze-smartphone MAC bezilokhu zisebenzisa ubuchwepheshe bokungahleliwe iminyaka eminingana. Ngokwethiyori, lapho iskena ama-airwaves ifuna amanethiwekhi aziwayo, i-smartphone ithumela iphakethe (iqembu lamaphakethe) lohlobo lwesicelo se-802.11 nekheli le-MAC njengomthombo:

I-randomization enikwe amandla ikuvumela ukuthi ungacacisi "elithungiwe", kodwa elinye ikheli lomthombo wephakethe, ukushintsha ngomjikelezo wokuskena ngamunye, ngokuhamba kwesikhathi, noma ngenye indlela. Ingabe iyasebenza? Ake sibheke izibalo zamakheli e-MAC aqoqwe emoyeni yilokho okubizwa ngokuthi “i-Wi-Fi Radar”:

Isampula yonke
Isampula kuphela ngoziro 7th bit

Inombolo yamarekhodi kusizindalwazi
3920000
305000

Inombolo encane:
% 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%

Isithombe sihluke ngokuphelele.

Ibhithi yesi-8 yebhayithi yokuqala yekheli le-MAC isahambisana nemvelo ye-Unicast yekheli le-SRC ephaketheni lesicelo sophenyo.

I-7th bit isethwe ku-Local in 92.2% yamacala, i.e. Ngezinga elifanele lokuzethemba, singacabanga ukuthi amakheli amaningi kangaka aqoqiwe awahleliwe, futhi angaphansi kuka-8% awangempela. Kulesi simo, ukusatshalaliswa kwamabhithi ku-OUI kulawo makheli angempela cishe kuqondana nedatha ekuthebula langaphambilini.

Imuphi umkhiqizi, ngokuya nge-OUI, ongumnikazi wamakheli angahleliwe (okungukuthi ngebhithi yesi-7 kokuthi “1”)?

Umkhiqizi yi-OUI
Yabelana phakathi kwawo wonke amakheli

ayitholakali kusizindalwazi se-IEEE
62.45%

Google Inc.
37.54%

phumula
0.01%

Ngaphezu kwalokho, wonke amakheli angahleliwe anikezwe i-Google awe-OUI efanayo nesiqalo DA:A1:19. Siyini lesi siqalo? Ake sibheke phakathi imithombo Android.

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

I-Stock Android isebenzisa i-OUI ekhethekile, ebhalisiwe lapho isesha amanethiwekhi angenawaya, okukodwa kwambalwa anesethi yebhithi yesikhombisa.

Bala i-MAC yangempela kusuka kokukodwa okungahleliwe

Ake sibone lapho:

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;
    }

Ikheli lonke, noma amabhayithi alo amathathu aphansi, ahlanzekile Okungahleliwe.nextLong()"Ukuvuselelwa kwe-MAC yangempela okunelungelo lobunikazi" kuwukukhwabanisa. Kungalindelwa ngokuqiniseka okukhulu ukuthi abakhiqizi AndroidAmanye ama-OUI angabhalisiwe nawo asetshenziswa kumafoni. Asinayo ikhodi yomthombo ye-iOS, kodwa kungenzeka ukuthi kusetshenziswa i-algorithm efanayo lapho.

Okungenhla akukhanseli umsebenzi wezinye izindlela zokuyekisa amagama ababhalisi be-Wi-Fi, ngokusekelwe ekuhlaziyweni kwezinye izinkambu zohlaka lwesicelo sophenyo, noma ukuhlotshaniswa kwemvamisa ehlobene yezicelo ezithunyelwa idivayisi. Nokho, ukulandelela ngokwethembekile obhalisile usebenzisa izindlela zangaphandle kuyinkinga kakhulu. Idatha eqoqiwe izofaneleka kakhulu ukuhlaziya isilinganiso/umthwalo ophezulu ngendawo nesikhathi, ngokusekelwe ezinombolweni ezinkulu, ngaphandle kokubhekisela kumadivayisi athile nabantu. Yilabo kuphela “abangaphakathi”, abakhiqizi be-OS yeselula ngokwabo, nezinhlelo zokusebenza ezifakiwe ezinedatha enembile.

Yini eyingozi ngomuntu ofunda ikheli le-MAC ledivayisi yakho? Ukuhlasela kokunqatshelwa kwesevisi kungaqaliswa kokubili kumanethiwekhi anezintambo kanye nangenantambo. Kudivayisi engenantambo, kukhona nethuba lokuthi ukuba khona kwayo endaweni yesensa kungatholakala. Ukukhwabanisa ikheli kungasetshenziswa ukuzenza idivayisi yakho, kodwa lokhu kuzosebenza kuphela uma izinyathelo zokuphepha ezengeziwe (ukugunyazwa kanye/noma ukubethela) zingekho. 99.9% Abantu lapha abanakho ukukhathazeka ngakho.

Ikheli le-MAC liyinkimbinkimbi kakhulu kunalokho elibonakala, kodwa lilula kunalokho obekungaba yikho.

Source: www.habr.com