树莓派zero,连接手机USB共享网络
树莓派zero，不像zeroW，具有板载wifi可以直接接入网络。当然也可以用usb无线网卡。
如果没有usb网卡，也可以用Android手机接入usb-host，进行usb网络共享，让树莓派zero接入网络！
RNDIS是指Remote NDIS，基于USB实现RNDIS实际上就是TCP/IP over USB，就是在USB设备上跑TCP/IP，让USB设备看上去像一块网卡。
基于buildroot
一、linux kernel 配置
buildroot 默认是开启RNDIS模块的，如果没有开启，则需要进行手动配置，make kinux-menuconfig
进入如下目录
> Device Drivers > Network device support > USB Network Adapters
重点三项设置
{*} Multi-purpose USB Networking Framework
{M} CDC Ethernet support (smart devices such as cable modems)
{M} Host for RNDIS and ActiveSync devices
二、查看已经加载的模块lsmod
[root@buildroot ~]#lsmod
Module Size Used by Not tainted
ipv6 446464 10 [permanent]
目前系统仅加载了ipv6模块，而没有rndis_host
手动加载：modprobe rndis_host
[root@buildroot ~]#modprobe rndis_host
[ 1322.908781] usbcore: registered new interface driver cdc_ether
[ 1322.928632] rndis_host 1-1:1.0 eth0: register 'rndis_host' at usb-20980000.usb-1, RNDIS device, 00:00:00:00:00:00
[ 1322.946885] usbcore: registered new interface driver rndis_host
[root@buildroot ~]#lsmod
Module Size Used by Not tainted
rndis_host 16384 0
cdc_ether 16384 1 rndis_host
ipv6 446464 10 [permanent]
手动加载完成，可以看到rndis_host、cdc_ether
三、将Android手机，接入树莓派0 usb-host接口
同时手机端，需要打开USB 网络共享
[root@buildroot ~]#[ 1485.716551] Indeed it is in host mode hprt0 = 00021501
[ 1485.936457] usb 1-1: new high-speed USB device number 3 using dwc_otg
[ 1485.947337] Indeed it is in host mode hprt0 = 00001101
[ 1486.199099] usb 1-1: New USB device found, idVendor=04e8, idProduct=6860, bcdDevice= 4.00
[ 1486.215091] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1486.226310] usb 1-1: Product: SAMSUNG_Android
[ 1486.234578] usb 1-1: Manufacturer: SAMSUNG
[ 1486.242461] usb 1-1: SerialNumber: b6a47799
[ 1489.516650] usb 1-1: USB disconnect, device number 3
[ 1489.726539] Indeed it is in host mode hprt0 = 00021501
[ 1489.936459] usb 1-1: new high-speed USB device number 4 using dwc_otg
[ 1489.947237] Indeed it is in host mode hprt0 = 00001101
[ 1490.198290] usb 1-1: New USB device found, idVendor=04e8, idProduct=6863, bcdDevice= 4.00
[ 1490.214325] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1490.225674] usb 1-1: Product: SAMSUNG_Android
[ 1490.234194] usb 1-1: Manufacturer: SAMSUNG
[ 1490.242332] usb 1-1: SerialNumber: b6a47799
[ 1490.257713] rndis_host 1-1:1.0 eth0: register 'rndis_host' at usb-20980000.usb-1, RNDIS device, 00:00:00:00:00:00
[root@buildroot ~]#
系统log可以看到，rndis_host 1-1:1.0 eth0，已经加载！并且已经识别到手机类型：三星
不同的手机，识别出来可能不一样，也可能是eth1,或者usb0之类！
也可以通过 dmesg 命令查看！
如果没有看到rndis_host 1-1:1.0 eth0字样，说明rndis设备没有被正确识别！
四、查看网络配置ifconfig
[root@buildroot ~]#ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
如果没有看到 eth0或usb0，再查看 ifconfig -a
[root@buildroot ~]#ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
ifconfig -a，可以看到 eth0 已经识别了，但MAC地址没有正确读出来
HWaddr 00:00:00:00:00:00
udhcpc -i eth0 ，提示ifconfig: SIOCSIFFLAGS: Cannot assign requested address
[root@buildroot /etc/network]#udhcpc -i eth0
udhcpc: started, v1.31.1
ifconfig: SIOCSIFFLAGS: Cannot assign requested address
ifconfig: SIOCSIFFLAGS: Cannot assign requested address
udhcpc: sending discover
udhcpc: sendto: Network is down
udhcpc: read error: Network is down, reopening socket
udhcpc: sending discover
udhcpc: sendto: Network is down
udhcpc: read error: Network is down, reopening socket
udhcpc: sending discover
udhcpc: sendto: Network is down
udhcpc: read error: Network is down, reopening socket
udhcpc: read error: Network is down, reopening socket
其实，这是三星手机的问题，需要手动设置mac地址。换华为手机，到这一步就可以正常上网！
五、设置MAC地址
两种方式设置MAC地址：
1、命令设置
ifconfig eth0 down
ifconfig eth0 hw ether AA:BB:CC:DD:EE:FF
ifconfig eth0 up
2、修改文件/etc/network/interfaces。此方式，重启也可以生效
[root@buildroot /etc/network]#vi interfaces
增加eth0相关描述
# interface file auto-generated by buildroot
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
hwaddress ether AA:BB:CC:DD:EE:FF
# address 192.168.2.2
# netmask 255.255.255.0
# network 192.168.2.0
# broadcast 192.168.2.255
# gateway 192.168.2.1
重新初始化网络，/etc/init.d/
[root@buildroot /etc/init.d]#./S40network restart
执行完成后，即可看到eth0已经生效！
[root@buildroot /etc/network]#ifconfig eth0 down
[root@buildroot /etc/network]#ifconfig eth0 hw ether AA:BB:CC:DD:EE:FF
[root@buildroot /etc/network]#ifconfig eth0 up
[root@buildroot /etc/network]#
[root@buildroot /etc/network]#
[root@buildroot /etc/network]#ifconfig
eth0 Link encap:Ethernet HWaddr AA:BB:CC:DD:EE:FF
inet6 addr: fe80::a8bb:ccff:fedd:eeff/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:26 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:5894 (5.7 KiB) TX bytes:780 (780.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
但此时还不能上网，因为还没有获取到正确的IP地址！执行udhcpc -i eth0
[root@buildroot /etc/network]#udhcpc -i eth0
udhcpc: started, v1.31.1
udhcpc: sending discover
udhcpc: sending discover
udhcpc: sending select for 192.168.42.132
udhcpc: lease of 192.168.42.132 obtained, lease time 3600
deleting routers
adding dns 192.168.42.129
获取到正确的IP地址后！ping www.baidu.com 测试！
[root@buildroot /etc/network]#ping www.baidu.com
PING www.baidu.com (180.101.49.11): 56 data bytes
64 bytes from 180.101.49.11: seq=0 ttl=51 time=14.582 ms
64 bytes from 180.101.49.11: seq=1 ttl=51 time=21.231 ms
64 bytes from 180.101.49.11: seq=2 ttl=51 time=20.914 ms
64 bytes from 180.101.49.11: seq=3 ttl=51 time=20.953 ms
^C
--- www.baidu.com ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 14.582/19.420/21.231 ms
此时网络已经接通！
六、设置开机自动加载rndis_host模块
以上设置比较繁琐，，并且每次开机都要重新设置！
/etc/init.d下新建文件S10modules
#!/bin/sh
# Load other user-defined modules
for file in /etc/init.d/*.modules ; do
[ -x $file ] && $file
done
# Load modules (for backward compatibility with VARs)
if [ -f /etc/init.d/rc.modules ]; then
/etc/init.d/rc.modules
fi
/etc/init.d下新建文件rndis_host.modules
#!/bin/sh
modprobe rndis_host.ko
设置权限755
[root@buildroot /etc/init.d]#chmod 755 S10modules
[root@buildroot /etc/init.d]#chmod 755 rndis_host.modules
重启reboot
[ 2.929930] usb 1-1: new high-speed USB device number 2 using dwc_otg
[ 2.941021] Indeed it is in host mode hprt0 = 00001101
[ 3.131470] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[ 3.213589] usb 1-1: New USB device found, idVendor=04e8, idProduct=6863, bcdDevice= 4.00
[ 3.229033] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3.240050] usb 1-1: Product: SAMSUNG_Android
[ 3.248262] usb 1-1: Manufacturer: SAMSUNG
[ 3.256080] usb 1-1: SerialNumber: b6a47799
Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
[ 3.578345] usbcore: registered new interface driver cdc_ether
[ 3.596246] rndis_host 1-1:1.0 eth0: register 'rndis_host' at usb-20980000.usb-1, RNDIS device, 00:00:00:00:00:00
[ 3.615653] usbcore: registered new interface driver rndis_host
hello world
Initializing random number generator: OK
Saving random seed: [ 3.742622] random: dd: uninitialized urandom read (512 bytes read)
OK
Starting network: [ 4.116974] NET: Registered protocol family 10
[ 4.128752] Segment Routing with IPv6
udhcpc: started, v1.31.1
[ 4.257709] random: mktemp: uninitialized urandom read (6 bytes read)
udhcpc: sending discover
udhcpc: sending select for 192.168.42.132
udhcpc: lease of 192.168.42.132 obtained, lease time 3600
deleting routers
[ 4.440324] random: mktemp: uninitialized urandom read (6 bytes read)
adding dns 192.168.42.129
OK
Welcome to Buildroot for eric
buildroot login: root
Password:
[root@buildroot ~]#
[root@buildroot ~]#
[root@buildroot ~]#ping www.baidu.com
PING www.baidu.com (180.101.49.12): 56 data bytes
64 bytes from 180.101.49.12: seq=0 ttl=51 time=19.564 ms
64 bytes from 180.101.49.12: seq=1 ttl=51 time=14.150 ms
64 bytes from 180.101.49.12: seq=2 ttl=51 time=19.795 ms
^C
--- www.baidu.com ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 14.150/17.836/19.795 ms
[root@buildroot ~]#
可以看到，开机后自动加载rndis_host 模块！
也可以，将rndis驱动，在内核编译的时候，设置成静态编译，就不需要动态加载。
还不支持热插拔，重新接入手机，需要再次初始化网络
[root@buildroot /etc/init.d]#./S40network restart
改进：
以上做法，只是手动配置加载rndis_host模块，buildroot是支持动态自动加载模块的，只是默认并未打开！打开后，就不需要手动创建S10modules了！
1、打开动态加载模块功能
make meunconfig
System configuration —>/dev management
选择
Dynamic using devtmpfs + mdev
/dev management (Dynamic using devtmpfs + mdev) --->
2、重新编译packet，make busybox。builtroot output/target/etc/init.d目录自动生成S10mdev
eric@eric-PC:~/Documents/work/linux-c/buildroot-2020.02.1/output/target/etc/init.d$ ls
rcK rcS S01syslogd S02klogd S02sysctl S10mdev S20urandom S40network S50userstart
3、重新编译生成镜像
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