Chilichonse chomwe mukufuna kudziwa za adilesi ya MAC

Aliyense amadziwa kuti ma byte asanu ndi limodzi awa, omwe nthawi zambiri amawonetsedwa mumtundu wa hexadecimal, amaperekedwa ku netiweki khadi pafakitale, ndipo amawoneka mwachisawawa. Anthu ena amadziwa kuti ma byte atatu oyamba a adilesi ndi ID ya wopanga, ndipo ma byte atatu otsala amapatsidwa kwa iwo. Zimadziwikanso kuti mutha kudziyika nokha mwachisawawa adilesi. Anthu ambiri amvapo za "maadiresi achisawawa" mu Wi-Fi.

Tiyeni tiwone chomwe icho chiri.

Adilesi ya MAC (media access control adilesi) ndi chizindikiritso chapadera chomwe chimaperekedwa ku adaputala ya netiweki, yogwiritsidwa ntchito pamanetiweki a miyezo ya IEEE 802, makamaka Ethernet, Wi-Fi ndi Bluetooth. Mwalamulo amatchedwa "EUI-48 Type Identifier". Kuchokera pa dzinali n'zoonekeratu kuti adiresi ndi 48 bits yaitali, i.e. 6 bati. Palibe mulingo wovomerezeka wolembera adilesi (kusiyana ndi adilesi ya IPv4, pomwe ma octets amasiyanitsidwa ndi madontho). Nthawi zambiri amalembedwa ngati manambala asanu ndi limodzi a hexadecimal olekanitsidwa ndi colon: 00:AB:CD:EF:11: 22, ngakhale ena opanga zida amakonda notation 00 -AB-CD-EF-11-22 komanso 00ab.cdef.1122.

M'mbuyomu, maadiresi adawunikira mu ROM ya chipset cha khadi la netiweki popanda kutha kuwasintha popanda pulogalamu yowunikira, koma masiku ano adilesiyo imatha kusinthidwa mwadongosolo kuchokera pamakina opangira. Mutha kukhazikitsa pamanja adilesi ya MAC ya khadi yapaintaneti ku Linux ndi MacOS (nthawi zonse), Windows (pafupifupi nthawi zonse, ngati dalaivala amalola), Android (yokhazikika mizu); Ndi iOS (popanda mizu) chinyengo choterocho sichingatheke.

Kapangidwe ka ma adilesi

Adilesi ili ndi gawo la chizindikiritso cha wopanga, OUI, ndi chizindikiritso choperekedwa ndi wopanga. Zozindikiritsa Zapadera za OUI (Organizationally Unique Identifier). amachita Bungwe la IEEE. M'malo mwake, kutalika kwake sikungakhale 3 mabayiti (24 bits), koma 28 kapena 36 bits, komwe kumatchinga (MAC Address Block, MA) ya maadiresi amitundu Yaikulu (MA-L), Medium (MA-M) ndi Zing'onozing'ono zimapangidwa (MA-S) motsatira. Kukula kwa chipika chomwe chinaperekedwa, pakadali pano, chidzakhala 24, 20, 12 bits kapena 16 miliyoni, 1 miliyoni, maadiresi 4 zikwi. Pakali pano pali midadada 38 yogawidwa, imatha kuwonedwa pogwiritsa ntchito zida zambiri zapaintaneti, mwachitsanzo. IEEE kapena Wireshark.

Eni ake ake ndi ndani?

Kukonza kosavuta kopezeka pagulu kutsitsa ma database IEEE imapereka zidziwitso zambiri. Mwachitsanzo, mabungwe ena adzitengera okha mabatani a OUI ambiri. Nawa ngwazi zathu:

Wogulitsa
Chiwerengero cha midadada/zolemba
Chiwerengero cha ma adilesi, miliyoni

Cisco Systems Inc
888
14208

apulo
772
12352

Samsung
636
10144

Malingaliro a kampani Huawei Technologies Co.Ltd
606
9696

Intel Corporation
375
5776

ARRIS Gulu Inc.
319
5104

Malingaliro a kampani Nokia Corporation
241
3856

Private
232
2704

Zida za Texas
212
3392

zte makampani
198
3168

IEEE Registration Authority
194
3072

Hewlett Packard
149
2384

Hon Hai Precision
136
2176

TP-KULUMIKIZANA
134
2144

Dell Inc.
123
1968

Mitundu Yopanga Mphungu
110
1760

Sagemcom Broadband SAS
97
1552

Malingaliro a kampani Fiberhome Telecommunication Technologies Co., Ltd. LTD
97
1552

Malingaliro a kampani Xiaomi Communications Co., Ltd
88
1408

Malingaliro a kampani Guangdong Oppo Mobile Telecommunications Corp.Ltd
82
1312

Google ili ndi 40 okha, ndipo izi sizosadabwitsa: iwowo samapanga zida zambiri zapaintaneti.

Ma block a MA saperekedwa kwaulere, amatha kugulidwa pamtengo wokwanira (popanda malipiro olembetsa) kwa $ 3000, $ 1800 kapena $ 755, motsatana. Chochititsa chidwi n'chakuti, pa ndalama zowonjezera (pachaka) mukhoza kugula "kubisa" kwa chidziwitso cha anthu za chipika chomwe chaperekedwa. Tsopano pali 232 a iwo, monga tawonera pamwambapa.

Kodi ma adilesi a MAC tidzatha liti?

Tonse tatopa kwambiri ndi nkhani zomwe zakhala zikuchitika kwa zaka 10 zoti "maadiresi a IPv4 atsala pang'ono kutha." Inde, midadada yatsopano ya IPv4 sikhalanso yosavuta kupeza. Zimadziwika kuti ma adilesi a IP kugawidwa mosiyanasiyana kwambiri; Pali midadada ikuluikulu komanso yosagwiritsidwa ntchito mokwanira yamakampani akulu ndi mabungwe aboma la US, komabe, opanda chiyembekezo chogawanso kwa omwe akufunika. Kuchulukirachulukira kwa NAT, CG-NAT ndi IPv6 kwapangitsa kuti vuto la kuchepa kwa maadiresi a anthu lisavutike kwambiri.

Adilesi ya MAC ili ndi ma bits 48, omwe 46 angatengedwe ngati "othandiza" (chifukwa chiyani? werengani), omwe amapereka ma adilesi 246 kapena 1014, omwe ndi 214 nthawi zambiri kuposa malo a adiresi a IPv4.
Pakali pano, pafupifupi theka la maadiresi thililiyoni agawidwa, kapena 0.73% yokha ya voliyumu yonse. Tidakali kutali kwambiri ndikusowa ma adilesi a MAC.

Zochita mwachisawawa

Zitha kuganiziridwa kuti ma OUI amagawidwa mwachisawawa, ndipo wogulitsa amagawiranso ma adilesi kuzipangizo zapaintaneti. Ndi choncho? Tiyeni tiwone kugawidwa kwa ma bits mu nkhokwe za ma adilesi a MAC a zida za 802.11 zomwe ndili nazo, zosonkhanitsidwa ndi machitidwe ovomerezeka ogwirira ntchito pamanetiweki opanda zingwe. WNAM. Ma adilesi ndi a zida zenizeni zomwe zimalumikizidwa ndi Wi-Fi pazaka zingapo m'maiko atatu. Kuphatikiza apo pali database yaying'ono ya zida za 802.3 zamawaya za LAN.

Tiyeni tidutse adilesi iliyonse ya MAC (ma byte asanu ndi limodzi) a zitsanzozo kukhala ma bits, byte byte, ndikuwona kuchuluka kwa "1" bit pagawo lililonse la 48. Ngati pang'onoyo idakhazikitsidwa mosasamala, ndiye kuti mwayi wopeza "1" uyenera kukhala 50%.

Kusankha kwa Wi-Fi No. 1 (RF)
Chitsanzo cha Wi-Fi nambala 2 (ku Belarus)
Kusankha kwa Wi-Fi nambala 3 (Uzbekistan)
LAN Sampling (RF)

Chiwerengero cha zolembedwa munkhokwe
5929000
1274000
366000
1000

Pang'ono nambala:
% pang'ono "1"
% pang'ono "1"
% pang'ono "1"
% pang'ono "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%

Chifukwa chiyani kupanda chilungamo koteroko mu 7 ndi 8 bits? Pali pafupifupi nthawi zonse ziro.

Zowonadi, muyezo umatanthauzira ma bits awa ngati apadera (Wikipedia):

Gawo lachisanu ndi chitatu (kuyambira pachiyambi) la byte yoyamba ya adilesi ya MAC limatchedwa Unicast/Multicast bit ndipo limatsimikizira mtundu wa chimango (chimango) chomwe chimaperekedwa ndi adilesi iyi, nthawi zonse (0) kapena kuwulutsa (1) (multicast kapena kufalitsa). Pakulankhulana kwabwinobwino, kwa unicast network adaputala, pang'ono iyi imayikidwa ku "0" m'mapaketi onse otumizidwako.

Gawo lachisanu ndi chiwiri (kuyambira pachiyambi) la baiti yoyamba ya adilesi ya MAC limatchedwa U/L (Universal/Local) ndipo limatsimikizira ngati adilesiyo ndi yapadera padziko lonse lapansi (0), kapena yapadera kwanuko (1). Mwachikhazikitso, maadiresi onse "opangidwa ndi opanga" ndi apadera padziko lonse lapansi, kotero kuti ma adilesi ambiri a MAC omwe asonkhanitsidwa amakhala ndi gawo lachisanu ndi chiwiri la "0". Pagome la zozindikiritsa za OUI, zolembedwa pafupifupi 130 zokha zili ndi U/L pang'ono "1", ndipo mwachiwonekere awa ndi midadada ya ma adilesi a MAC pazosowa zapadera.

Kuchokera pa chisanu ndi chimodzi kufika pa ma bitti oyambirira a byte yoyamba, ma byte achiwiri ndi achitatu mu zozindikiritsa za OUI, ndipo makamaka ma bitti a 4-6 mabaiti a adilesi yomwe wopanga amagawira amagawidwa mocheperapo kapena mocheperapo. .

Chifukwa chake, mu adilesi yeniyeni ya MAC ya adapter ya netiweki, ma bits ndi ofanana ndipo alibe tanthauzo laukadaulo, kupatula ma bits awiri amtundu wamtundu wapamwamba.

Kuchuluka

Mukudabwa kuti ndi opanga zida ziti opanda zingwe omwe ali otchuka kwambiri? Tiyeni tiphatikize kusaka munkhokwe ya OUI ndi data yachitsanzo Nambala 1.

Wogulitsa
Kugawana kwa zida, %

apulo
26,09

Samsung
19,79

Malingaliro a kampani Huawei Technologies Co. Ltd
7,80

Malingaliro a kampani Xiaomi Communications Co., Ltd
6,83

Malingaliro a kampani Sony Mobile Communications Inc
3,29

LG Electronics (Mobile Communications)
2,76

Mtengo wa magawo ASUSTEK COMPUTER INC.
2,58

Malingaliro a kampani TCT Mobile Ltd
2,13

zte makampani
2,00

sichipezeka mu database ya IEEE
1,92

Malingaliro a kampani Lenovo Mobile Communication Technology Limited
1,71

Malingaliro a kampani HTC Corporation
1,68

Murata Manufacturing
1,31

InPro Comm
1,26

Microsoft Corporation
1,11

Malingaliro a kampani Shenzhen TINNO Mobile Technology Corp.
1,02

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

Malingaliro a kampani Nokia Corporation
0,88

Malingaliro a kampani Shanghai Wind Technologies Co., Ltd. Ltd
0,74

Lenovo Mobile Communication (Wuhan) Company Limited
0,71

Zoyeserera zikuwonetsa kuti kutukuka kwa omwe amalembetsa ma netiweki opanda zingwe pamalo enaake, kumapangitsa kuti zida za Apple zichuluke.

Zapadera

Kodi ma adilesi a MAC ndi apadera? Mwachidziwitso, inde, popeza aliyense wopanga chipangizo (MA block eni) amayenera kupereka adilesi yapadera pa ma adapter amtundu uliwonse omwe amapanga. Komabe, ena opanga chip, omwe ndi:

• 00:0A:F5 Airgo Networks, Inc. (tsopano Qualcomm)
• 00:08:22 InPro Comm (tsopano MediaTek)

ikani ma byte atatu omaliza a adilesi ya MAC ku nambala yachisawawa, mwachiwonekere chipangizo chilichonse chikayambiranso. Panali 1 zikwi maadiresi oterowo mu chitsanzo changa No.

Mukhoza, ndithudi, kudzikhazikitsira adiresi yachilendo, yosakhala yachilendo poyiyika mwadala "monga mnzako", kuzindikiritsa ndi sniffer, kapena kusankha mwachisawawa. Ndikothekanso kudzipangira mwangozi adilesi yosakhala yapadera, mwachitsanzo, kubwezeretsa kasinthidwe ka rauta ngati Mikrotik kapena OpenWrt.

Kodi chingachitike ndi chiyani ngati pali zida ziwiri pamaneti zomwe zili ndi adilesi yomweyo ya MAC? Zonse zimatengera malingaliro a zida zamaneti (wired rauta, wowongolera opanda zingwe). Mwachidziwikire, zida zonsezi sizingagwire ntchito kapena zizigwira ntchito modukizadukiza. Kuchokera pamalingaliro amiyezo ya IEEE, chitetezo ku kuwononga adilesi ya MAC chikufunsidwa kuti chithetsedwe pogwiritsa ntchito, mwachitsanzo, MACsec kapena 802.1X.

Bwanji ngati muyika MAC yokhala ndi gawo lachisanu ndi chiwiri kapena lachisanu ndi chitatu kukhala "1", i.e. kwanuko kapena ma adilesi ambiri? Mwachidziwikire, maukonde anu sangalabadire izi, koma mwamwayi ma adilesi oterowo sangagwirizane ndi muyezo, ndipo ndi bwino kusatero.

Momwe randomisation imagwirira ntchito

Tikudziwa kuti pofuna kupewa kutsata mayendedwe a anthu posanthula ndi kusonkhanitsa ma airwaves, makina opangira ma smartphone a MAC akhala akugwiritsa ntchito ukadaulo wa randomisation kwa zaka zingapo. Mwamwayi, poyang'ana ma airwaves posaka maukonde odziwika, foni yamakono imatumiza paketi (gulu la mapaketi) amtundu wa pempho la 802.11 ndi adilesi ya MAC monga gwero:

Kutsegula mwachisawawa kumakupatsani mwayi kuti musatchule "yosokedwa", koma adilesi ina ya paketi, kusintha ndikusanthula kulikonse, pakapita nthawi, kapena mwanjira ina. Kodi zimagwira ntchito? Tiyeni tiwone ziwerengero zamaadiresi a MAC omwe amasonkhanitsidwa kuchokera mlengalenga ndi omwe amatchedwa "Wi-Fi Radar":

Chitsanzo chonse
Chitsanzo chokha ndi zero 7th bit

Chiwerengero cha zolembedwa munkhokwe
3920000
305000

Pang'ono nambala:
% pang'ono "1"
% pang'ono "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%

Chithunzicho ndi chosiyana kwambiri.

Gawo lachisanu ndi chitatu la adilesi yoyamba ya adilesi ya MAC limafananabe ndi mtundu wa Unicast wa adilesi ya SRC mu paketi yofunsira.

Gawo la 7 limayikidwa ku Local mu 92.2% ya milandu, i.e. Pokhala ndi chidaliro chokwanira, titha kuganiza kuti ma adilesi osonkhanitsidwa ndendende ndi osasinthika, ndipo ochepera 8% ndi enieni. Pamenepa, kugawidwa kwa ma bits mu OUI kwa ma adilesi enieni oterowo pafupifupi kumagwirizana ndi zomwe zili mu tebulo lapitalo.

Ndi wopanga uti, malinga ndi OUI, yemwe ali ndi ma adilesi osasinthika (ie ndi 7th bit mu "1")?

Wopanga ndi OUI
Gawani pakati pa ma adilesi onse

sichipezeka mu database ya IEEE
62.45%

Google Inc.
37.54%

kupuma
0.01%

Komanso, maadiresi onse osankhidwa mwachisawawa omwe amaperekedwa ku Google ndi a OUI yomweyi ndi mawu oyamba DA:A1:19. Kodi mawu oyambawa ndi chiyani? Tiyeni tione mkati Magwero a Android.

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

Stock Android imagwiritsa ntchito OUI yapadera, yolembetsedwa pofufuza maukonde opanda zingwe, imodzi mwa ochepa omwe ali ndi seti yachisanu ndi chiwiri.

Werengerani MAC yeniyeni kuchokera kumodzi mwachisawawa

Tiyeni tiwone pamenepo:

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;
    }

Adilesi yonse, kapena ma byte atatu otsika, ndi oyera Random.nextLong(). "Kubwezeretsanso kwa MAC yeniyeni" ndichinyengo. Ndi chidaliro chachikulu, titha kuyembekezera kuti opanga mafoni a Android agwiritse ntchito ma OUI ena osalembetsedwa. Tilibe code source source ya iOS, koma nthawi zambiri ma algorithm ofanana amagwiritsidwa ntchito pamenepo.

Zomwe zili pamwambazi siziletsa ntchito ya njira zina zodziwikiratu olembetsa a Wi-Fi, kutengera kuwunika kwa magawo ena a kafukufuku wofunsira, kapena kulumikizana pafupipafupi kwa zopempha zomwe zimatumizidwa ndi chipangizocho. Komabe, kutsatira modalirika wolembetsa pogwiritsa ntchito njira zakunja ndikovuta kwambiri. Deta yomwe yasonkhanitsidwa idzakhala yoyenera kuwunika kuchuluka kwa kuchuluka / kuchuluka kwa katundu ndi malo ndi nthawi, kutengera kuchuluka kwa anthu, osatengera zida ndi anthu. Okhawo "mkati", opanga mafoni a OS okha, ndi mapulogalamu omwe adayikidwa ali ndi deta yolondola.

Ndi chiyani chomwe chingakhale chowopsa ngati wina akudziwa adilesi ya MAC ya chipangizo chanu? Kukanidwa kwa ntchito kutha kukhazikitsidwa pamanetiweki opanda zingwe komanso opanda zingwe. Kwa chipangizo chopanda zingwe, komanso, ndi mwayi wina ndizotheka kulemba nthawi ya maonekedwe ake pamalo omwe sensor imayikidwa. Mwa kuwononga adilesi, mungayesere "kudziyesa" ngati chipangizo chanu, chomwe chingagwire ntchito ngati palibe njira zowonjezera zotetezera zomwe zimagwiritsidwa ntchito (chilolezo ndi / kapena kubisa). 99.9% ya anthu pano alibe chodetsa nkhawa.

Adilesi ya MAC ndi yovuta kuposa momwe ikuwonekera, koma yosavuta kuposa momwe ingakhalire.

Source: www.habr.com