Android 4.2 Bluetooth and Network Internal Class (Inatel Embedded Software Specialization December - 2016) - Bluetooth - Wifi - Wandboard / IMX6

3. Apresentação da
Placa Wandboard

4. Wandboard
Processador Freescale i.MX6 Quad
Cores Quad Cortex-A9
Graphic Engine Vivante GC 2000 + Vivante GC 350 + Vivante GC
320
Memória RAM 2GB DDR3
Audio 1
HDMI 1 Output
Micro-SD Slot 2
Serial Port 1
USB 1
USB OTG 1
Gigabit LAN 1
Wifi (802.11n) 1
Bluetooth 4.1 1

5. Wandboard

6. Wandboard

7. Wandboard
HDMI
5V 2A
USB OTG
USB

8. Wandboard
http://www.wandboard.org

9. Arquitetura Wi-Fi Linux

10. Arquitetura
•cfg80211 – API de configuração para o padrão 802.11
•mac80211 – Implementação da camada MAC (Medium Access Control)
para SoftMAC
•Wireless Module Driver .ko
•Wireless Module Firmware
•Wireless Module configuration
Interfaces de I/O
•PCIe (Média / Alta Capacidade)
•SDIO – Secure Digital I/O (Baixa / Média Capacidade)
•USB (Baixa / Média Capacidade)
•Serial (Baixa Capacidade)

11. Linux Wi-Fi - SoftMAC
•Processamento do MAC em software (CPU)
•Fácil atualização
•Chips mais baratos
•Maior consumo de energia na CPU
•Menor desempenho
User Space
cfg80211
mac80211
Driver
Hardware

12. Linux Wi-Fi - FullMAC
•Processamento do MAC é realizado na Interface
•Atualização depende muito mais do fabricante
•Chips mais caros
•Menor consumo de CPU
•Maior Desempenho
User Space
cfg80211
Driver
Hardware

13. Linux Wi-Fi – Arquitetura
WEXT
Wireless Extension – Desenvolvido em 1997, foi a primeira
implementação de Wireless para Linux, algumas versões do
Utilizada em versões do Android anteriores a 4.2
O acesso ao driver é através de ioctl()
nl80211
Atual implementação para dispositivos Wireless no Linux
(cfg80211 / mac80211)
Realiza o acesso aos drivers através do protocolo netlink.
Possui retrocompatibilidade com WEXT.

14. Linux Wi-Fi – Arquitetura

15. Arquitetura de Rede Android

16. Tecnologias suportadas pelo Android
•Mobile: GSM / EDGE / HSDPA / LTE
•Wi-Fi
•Bluetooth
•Ethernet
•WiMax*

17. Arquitetura de Rede do Android
•Kernel Drivers (Ethernet, Wi-Fi, Bluetooth, WiMax...)
•Kernel TCP/IP Layer , POSIX user-space API support
•Android Hardware Abstraction Layer (HAL)
•Android Bionic C library
•Android libnetutils (Network Utilities)
•Android Netd (Network Daemon)
•Android ConnectivityManager e ConnectivityService
•Android Java Apps

18. Bionic C
O Android não implementa as configurações básicas de
interfaces de rede como conhecemos no Linux.
•/etc/network/interfaces
•/etc/resolv.conf
•Etc...
Todas essas informações estão disponíveis apenas através
dos comandos getprop / setprop

19. Bionic C
root@wandboard: # getprop | grep dhcp
[dhcp.eth0.pid]: [2684]
[dhcp.eth0.reason]: [PREINIT]
[dhcp.eth0.result]: [failed]
[dhcp.wlan0.dns1]: [192.168.1.1]
[dhcp.wlan0.dns2]: []
[dhcp.wlan0.dns3]: []
[dhcp.wlan0.dns4]: []
[dhcp.wlan0.domain]: [Home]
[dhcp.wlan0.gateway]: [192.168.1.1]
[dhcp.wlan0.ipaddress]: [192.168.1.5]
[dhcp.wlan0.leasetime]: [86400]
[dhcp.wlan0.mask]: [255.255.255.0]
[dhcp.wlan0.pid]: [4791]
[dhcp.wlan0.reason]: [REBOOT]
[dhcp.wlan0.result]: [failed]
[dhcp.wlan0.server]: [192.168.1.1]
[dhcp.wlan0.vendorInfo]: []

20. Netd / Libnetutils
Netd
•Responsável pelo gerenciamento das interfaces
•O Daemon é acessado através de Unix Socket.
• Pode ser controlado por apps ou através do comando ndc
Libnetutils
•Disponibiliza acesso baixo nível ao controle das interfaces
•Disponibiliza acesso a API para ifconfig / netcfg / route /
dhcpcd / dhcpc
•É utilizado pelo HAL e System Framework para controlar
as interfaces

21. Netd – Network Daemon
•Operação , Gerenciamento e Armazenamento de
informações das interfaces de rede
•Estatística de tráfego
•Controle de Banda (Quota)
•Gerenciamento das Tabelas de Roteamento
•Firewall
•NAT – Network Translation Address
•PAN – Personal Area Network
•Links PPP – Point to Point Protocol
•SoftAP (Hotspot)
•Tethering
•….

22. Netd – Network Daemon

23. Netd – Network Daemon
Documentação Oficial: Código Fonte
Netd
/system/netd
lib
/system/core/libsysutils/src
Framework
/frameworks/base/services/java/com/android/server/NetworkManagamentService.java
/frameworks/base/services/java/com/android/server/NativeDaemonConnector.java

24. Acessando o Netd através do command ndc
root@wandboard:/ # ndc
Usage: ndc [sockname] <monitor>|<cmd> [arg1] [arg2...]
root@wandboard:/ # ndc --help
500 0 Command not recognized
Como saber quais comandos utilizar ?

25. NDC – Network Daemon Command
NDC
/system/netd/ndc.cpp
/system/netd/CommandListener.cpp
Framework
/frameworks/base/services/java/com/android/server/NetworkManagamentService.java
CommandListener::CommandListener() :
FrameworkListener("netd", true) {
registerCmd(new InterfaceCmd());
registerCmd(new IpFwdCmd());
registerCmd(new TetherCmd());
registerCmd(new NatCmd());
registerCmd(new ListTtysCmd());
registerCmd(new PppdCmd());
registerCmd(new SoftapCmd());
registerCmd(new BandwidthControlCmd());
registerCmd(new IdletimerControlCmd());
registerCmd(new ResolverCmd());
registerCmd(new FirewallCmd());
registerCmd(new ClatdCmd());
event = mConnector.execute("interface", "getcfg", iface);
mConnector.execute("interface", "ipv6privacyextensions", iface, enable ? "enable" : "disable");
event = mConnector.execute("ipfwd", "status");
mConnector.execute("pppd", "attach", tty,
NetworkUtils.numericToInetAddress(localAddr).getHostAddress(),
NetworkUtils.numericToInetAddress(remoteAddr).getHostAddress(),
NetworkUtils.numericToInetAddress(dns1Addr).getHostAddress(),
NetworkUtils.numericToInetAddress(dns2Addr).getHostAddress());

26. NDC – Network Daemon Command

27. NDC – Network Daemon Command

28. Netd – Inicialização
Init.rc

29. Arquitetura Wi-Fi Android

30. Arquitetura Wi-Fi Android
O Android 4.3 suporta três modos de operação para
a interface Wi-Fi
•Cliente
•SoftAp
•P2P

31. Inicialização
Init.wandboard.rc
rc.wifi

32. Arquitetura Wi-Fi Android
A Arquitetura Wi-Fi do Android pode ser dividida em três
partes.
•Framework Java: (WifiManager, WifiMonitor, WifiSettings, WifiService,
WifiStateMachine, WifiNative...)
•HAL: wifi.c, wpa_supplicant, hostapd, netd…
•Kernel Space Modules: Wireless Stack, Wifi Drivers , Wifi Firmwares.

33. Arquitetura Wi-Fi Android

35. Arquitetura Wi-Fi Android – Framework Java
•WifiManager
Responsável por disponibilizar a API para outras
aplicações (Connectivity Manager) para que seja
possível gerenciar todos parâmetros de
conectividade da interface Wi-Fi.
lRealizar comunicação com o WifiServices através
do Binder.
lPath:
l/frameworks/base/wifi/java/android/net/wifi/WifiManager.java

36. Arquitetura Wi-Fi Android - Framework Java
•WifiService
Responsável por reportar os eventos da Interface
Wi-Fi e realizar a integração com o Binder (IPC).
Path:
/frameworks/base/services/java/com/android/server/WifiService.java

37. Arquitetura Wi-Fi Android - Framework Java
WifiStateMachine
Responsável realizar o gerenciamento do “ciclo de
do funcionamento” da interface Wi-Fi.
Três tipos de estados:
Enter(): executado quando entra no estado
Exit(): executando quando saí do estado atual
ProcessMessage(): executando quando é
recebido uma mensagem
Path:
/frameworks/base/wifi/java/android/net/wifi/WifiStateMachine.java

38. WifiStateMachine

39. Arquitetura Wi-Fi Android - Framework Java
WifiMonitor
•Responsável receber eventos e informações do
wpa_supplicant / hostapd / p2p
•Comunicação através de Sockets
WifiNative
•Responsável por enviar os comandos para a HAL
•Comunicação através do JNI
Path:
/frameworks/base/wifi/java/android/net/wifi/WifiMonitor.java
/frameworks/base/wifi/java/android/net/wifi/WifiNative.java

40. Arquitetura Wi-Fi Android - HAL
WifiJNI
•Realiza a interface de serviços Java e C/C++ (HAL)
Path:
/frameworks/base/core/jni/android_net_wifi_Wifi.cpp
/*
* JNI registration.
*/
static JNINativeMethod gWifiMethods[] = {
/* name, signature, funcPtr */
{ "loadDriver", "()Z", (void *)android_net_wifi_loadDriver },
{ "isDriverLoaded", "()Z", (void *)android_net_wifi_isDriverLoaded },
{ "unloadDriver", "()Z", (void *)android_net_wifi_unloadDriver },
{ "startSupplicant", "(Z)Z", (void *)android_net_wifi_startSupplicant },
{ "killSupplicant", "(Z)Z", (void *)android_net_wifi_killSupplicant },
{ "connectToSupplicant", "(Ljava/lang/String;)Z",
(void *)android_net_wifi_connectToSupplicant },
{ "closeSupplicantConnection", "(Ljava/lang/String;)V",
(void *)android_net_wifi_closeSupplicantConnection },
{ "waitForEvent", "(Ljava/lang/String;)Ljava/lang/String;",
(void*) android_net_wifi_waitForEvent },
{ "doBooleanCommand", "(Ljava/lang/String;Ljava/lang/String;)Z",
(void*) android_net_wifi_doBooleanCommand },
{ "doIntCommand", "(Ljava/lang/String;Ljava/lang/String;)I",
(void*) android_net_wifi_doIntCommand },
{ "doStringCommand", "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;",
(void*) android_net_wifi_doStringCommand },

41. Arquitetura Wi-Fi Android - HAL
HAL
•Camada de abstração
•Funcionalidades para carregar firmware
•Inicializar/Finalizar driver e serviços (dhcp,
wpa_supplicant,hostapd, dhcpc, dhcpd..)
•Preparar interface de controle dos serviços
•Criar arquivo de entropia
•Carregar arquivos de configuração dos serviços
A implementação desta camada é responsabilidade do
fabricante do driver do módulo Wifi
Path:
/hardware/libhardware_legacy/wifi/wifi.c
/hardware/broadcom/wlan/bcmdhd/*

42. WPA_SUPPLICANT / HOSTAPD
•Os serviços hostapd e wpa_supplicant possuem
interfaces de controle via socket.
•Após inicializados é possível controlar os serviços via
console/adb utilizando as ferramentas wpa_cli e
hostapd_cli.
•As ferramentas possuem help com a relação dos
comandos que podem ser utilizados
•Alguns comandos dependem da implementação do driver
Para saber mais sobre os comandos que o Android envia ao
HAL consulte o arquivo WifiNative.java

43. WifiNative – comandos
/**
* Format of results:
* =================
* id=1
* bssid=68:7f:74:d7:1b:6e
* freq=2412
* level=-43
* tsf=1344621975160944
* age=2623
* flags=[WPA2-PSK-CCMP][WPS][ESS]
* ssid=zubyb
* ====
*
* RANGE=ALL gets all scan results
* RANGE=ID- gets results from ID
* MASK=<N> see wpa_supplicant/src/common/wpa_ctrl.h for details
*/
public String scanResults(int sid) {
return doStringCommand("BSS RANGE=" + sid + "- MASK=0x21987");
}
public boolean startDriver() {
return doBooleanCommand("DRIVER START");
}
public boolean stopDriver() {
return doBooleanCommand("DRIVER STOP");
}

44. Arquivo de configuração - wpa_supplicant.conf
Target: data/misc/wifi/wpa_supplicant.conf
##### wpa_supplicant configuration file template #####
update_config=1
ctrl_interface=DIR=/data/system/wpa_supplicant GROUP=wifi
eapol_version=1
ap_scan=1
fast_reauth=1
config_methods=virtual_push_button physical_display keypad
p2p_listen_channel=11
p2p_listen_reg_class=81
network={
ssid="lab1"
psk="123456789a"
key_mgmt=WPA-PSK
priority=2
}

45. Connectivity Manager
•Monitorar conexões (Wi-Fi , GPRS, UMTS, etc)
•Informar alteração do status de rede (Intent Broadcast)
•“Fail Over” entre interfaces de rede
•Fornecer API para aplicações verificarem status e
disponibilidade da rede
•Disponibilizar API para permitir ao aplicativo selecionar
qual interface de rede será utilizada para envio/recebimento
de informações

46. Connectivity Manager

47. Arquitetura Bluetooth Android

48. Android Bluetooth
BlueZ
•Utilizado até a versão Android 4.1 (2012)
•Licença GPL
•O port do BlueZ para Android é mantido fora da AOSP
•https://01.org/bluez-android
Bluedroid
•Foi integrado na AOSP a partir da versão 4.2
•Toda Stack é executada em User Space
•Desenvolvida inicialmente pela Broadcom
•Necessidade de adequar ao licenciamento do Android
•Foi considerado estável apenas na versão Android 6.0
•Em sua versão inicial suporta apenas dispositivos com
interface serial

49. Bluetooth - Bluedroid
Distribuição do código fonte:
Application
/packages/apps/Settings/src/com/android/settings/bluetooth
Java Framework
/frameworks/base/core/java/android/bluetooth
JNI
/packages/apps/Bluetooth/jni/com_android_bluetooth_{profile}.cpp
HAL- (BTIF – Bluetooth Interface)
/hardware/libhardware/include/hardware/bt_*.h
Bluetooth App (BTA – Bluetooth Application)
/packages/apps/Bluetooth/src/com/android/bluetooth
BlueDroid
/external/bluetooth/bluedroid
/system/bluetooth (adaptation code)

50. Bluedroid - Arquitetura

51. Profiles Suportados pelo BlueDroid no Android 4.3
•HFP – Hands Free Profile
•A2DP – Advance Audio Distribution
•HDP – Health Device Profile
•SPP – Serial Port Profile
•HID – Human Interface Device Profile
•PAN – Personal Area Network
•SDAP – Service Discovery Application Protocol
•HFP – Hands Free Profile
•MAP – Message Access Profile
•OPP - Object Push Profile
•PABP – Phone Book Access Profile
•AVRCP – Audio/Video Remote Control Profile
•GATT – Generic Attribute Profile
https://developer.bluetooth.org/TechnologyOverview/Pages/Profiles.aspx

52. Os profiles são implementados na HAL, BlueDroid e
possuem conectores JNI.
/hardware/libhardware/include/hardware/bluetooth.h (HAL)
/hardware/libhardware/include/hardware/bt_{profile}.h
/packages/apps/Bluetooth/jni/com_android_bluetooth_{profile}.cpp
Bluetooth - Profiles

53. /* Bluetooth profile interface IDs */
#define BT_PROFILE_HANDSFREE_ID "handsfree"
#define BT_PROFILE_ADVANCED_AUDIO_ID "a2dp"
#define BT_PROFILE_HEALTH_ID "health"
#define BT_PROFILE_SOCKETS_ID "socket"
#define BT_PROFILE_HIDHOST_ID "hidhost"
#define BT_PROFILE_PAN_ID "pan"
#define BT_PROFILE_GATT_ID "gatt"
#define BT_PROFILE_AV_RC_ID "avrcp"
/* Bluetooth profile interface IDs */
#define BT_PROFILE_HANDSFREE_ID "handsfree"
#define BT_PROFILE_HANDSFREE_CLIENT_ID
"handsfree_client"
#define BT_PROFILE_ADVANCED_AUDIO_ID "a2dp"
#define BT_PROFILE_ADVANCED_AUDIO_SINK_ID
"a2dp_sink"
#define BT_PROFILE_HEALTH_ID "health"
#define BT_PROFILE_SOCKETS_ID "socket"
#define BT_PROFILE_HIDHOST_ID "hidhost"
#define BT_PROFILE_PAN_ID "pan"
#define BT_PROFILE_MAP_CLIENT_ID "map_client"
#define BT_PROFILE_SDP_CLIENT_ID "sdp"
#define BT_PROFILE_GATT_ID "gatt"
#define BT_PROFILE_AV_RC_ID "avrcp"
#define BT_PROFILE_AV_RC_CTRL_ID "avrcp_ctrl"
Android 4.3 Android 6.0
/hardware/libhardware/include/hardware/bluetooth.h
Bluetooth - HAL

54. ├── com_android_bluetooth_a2dp.cpp
├── com_android_bluetooth_avrcp.cpp
├── com_android_bluetooth_btservice_AdapterService.cpp
├── com_android_bluetooth_gatt.cpp
├── com_android_bluetooth.h
├── com_android_bluetooth_hdp.cpp
├── com_android_bluetooth_hfp.cpp
├── com_android_bluetooth_hid.cpp
└── com_android_bluetooth_pan.cpp
Android 4.3 Android 6.0
Bluetooth – HAL / JNI
/packages/apps/Bluetooth/jni
── com_android_bluetooth_a2dp.cpp
├── com_android_bluetooth_a2dp_sink.cpp
├── com_android_bluetooth_avrcp_controller.cpp
├── com_android_bluetooth_avrcp.cpp
├── com_android_bluetooth_btservice_AdapterServi
├── com_android_bluetooth_gatt.cpp
├── com_android_bluetooth.h
├── com_android_bluetooth_hdp.cpp
├── com_android_bluetooth_hfpclient.cpp
├── com_android_bluetooth_hfp.cpp
├── com_android_bluetooth_hid.cpp
├── com_android_bluetooth_pan.cpp
└── com_android_bluetooth_sdp.cpp

55. ├── bluetooth.h
├── bt_av.h
├── bt_gatt_client.h
├── bt_gatt.h
├── bt_gatt_server.h
├── bt_gatt_types.h
├── bt_hf.h
├── bt_hh.h
├── bt_hl.h
├── bt_pan.h
├── bt_rc.h
├── bt_sock.h
├── bluetooth.h
├── boot_control.h
├── bt_av.h
├── bt_common_types.h
├── bt_gatt_client.h
├── bt_gatt.h
├── bt_gatt_server.h
├── bt_gatt_types.h
├── bt_hf_client.h
├── bt_hf.h
├── bt_hh.h
├── bt_hl.h
├── bt_mce.h
├── bt_pan.h
├── bt_rc.h
├── bt_sdp.h
├── bt_sock.h
Android 4.3 Android 6.0
Bluetooth - HAL
/hardware/libhardware/include/hardware/

56. Android 4.3
Bluetooth - libbtvendor
fsl/
└── wandboard
├── Android.mk
└── bt_vendor.conf
hardware/broadcom/libbt/conf
.
├── bt_vendor_brcm.c
├── conf.c
├── hardware.c
├── upio.c
└── userial_vendor.c
hardware/broadcom/libbt/src
hardware/broadcom/libbt/include
├── bt_vendor_brcm.h
├── upio.h
├── userial_vendor.h
├── vnd_crespo4g.txt
├── vnd_crespo.txt
├── vnd_generic.txt
├── vnd_generic_x86.txt
├── vnd_grouper.txt
├── vnd_hammerhead.txt
├── vnd_maguro.txt
├── vnd_mako.txt
├── vnd_manta.txt
├── vnd_phantasm.txt
├── vnd_stingray.txt
├── vnd_tilapia.txt
├── vnd_toro.txt
├── vnd_tuna.txt
└── vnd_wingray.txt

57. Bluetooth – Arquivos de Configurações
wandboard.mk
Host: system/bluetooth/data/
Target: system/etc/bluetooth
├── audio.conf
├── auto_pairing.conf
├── blacklist.conf
├── input.conf
├── main.conf
├── main.le.conf
├── main.nonsmartphone.conf
├──
main.nonsmartphone.le.conf
└── network.conf

58. Dúvidas ?

59. Obrigado!
Caio Pereira – caiop@inatel.br

60. Referências Bibliográficas
[1] WPA Supplicant Devel - http://w1.fi/wpa_supplicant/wpa_supplicant-devel.pdf
[2] Android Wi-Fi Manager and Bluetooth - http://pt.slideshare.net/pohjus/android-wifi-manager-and-bluetooth-connection
[3] Android 4.1 Netd detailed analysis of a Overview and Applications http://blog.csdn.net/xiaokeweng/article/details/8130218
[4] BirdView of Wifi in Linux/Android - http://pt.slideshare.net/leohyang66/wifiswbirdviewv04-46410468?related=1
[5] Android Service Black Magic - http://pt.slideshare.net/marakana/android-services-black-magic-by-aleksandar-gargenta
[6] Android Lollipop : Bluetooth LE Matures - https://newcircle.com/s/post/1697/android_lollipop_bluetooth_andevcon
[7] CLAT - http://dan.drown.org/android/clat/
[8] Linux Wireless Linux Kernel Networking (4) Advanced Topics - http://www.haifux.org/lectures/206/wirelessLec.pdf
[9] Linux 802.11 Solutions for Mobile Platforms - http://elinux.org/images/d/da/Ortiz-elce-2009.pdf
[10] Comparison of Open Source Wireless Driver - https://en.wikipedia.org/wiki/Comparison_of_open-source_wireless_drivers
[11] mac80211 Overview - https://wireless.wiki.kernel.org/_media/en/developers/documentation/mac80211.pdf
[12] Android.net.wifi - http://developer.android.com/intl/pt-br/reference/android/net/wifi/package-summary.html
[13] Returning BlueZ to Android - https://lwn.net/Articles/597293/
[14]Android Bluetooth Stack - https://source.android.com/devices/bluetooth.html
[15] Dive Into Android Networking: Adding Ethernet Connectivity - http://pt.slideshare.net/gxben/abs-2013-dive-into-android-networking-
adding-ethernet-connectivity
[16] Android Kitkat Internals - http://events.linuxfoundation.org/sites/events/files/slides/ABS%202014%20-%20Kit%20Kat%20Internals.pdf
[17] How to Support New WiFI Card in Android - https://community.freescale.com/docs/DOC-93603
[18] How Android Wifi State Machine Works - http://jhshi.me/2014/04/25/how-android-wifi-state-machine-works/
[19] – Android Bluetooth Stack: Bluedroid: The analysis of A2DP Source - http://blog.csdn.net/wendell_gong/article/details/29841967
[20] – Android Bluetooth Stack: Bluedroid - http://blog.csdn.net/wendell_gong/article/details/9630311
[21] – Android – Bluetooth Entry - http://blog.csdn.net/sungang860820/article/details/40344623
[22] – Android Bluetooth Stack: Bluedroid: Enable Bluetooth - http://blog.csdn.net/wendell_gong/article/details/9716619
[23] – Android Bluetooth OPP File Transfer - http://blog.csdn.net/safrans/article/details/27403287
[24] – Android Bluetooth Architecture (BlueZ) - http://blog.csdn.net/adazone/article/details/41082457
[25] – Android Bluetooth Introduction: Basic Concept and Hardware Interface - http://blog.csdn.net/adazone/article/details/41082405
[26] – Android ConnectivityManager - http://developer.android.com/intl/pt-br/reference/android/net/ConnectivityManager.html
[27] – Determining and Monitoring the Connectivity Status - http://developer.android.com/intl/pt-br/training/monitoring-device-
state/connectivity-monitoring.html