Android 网络配置-编程知识

adb root

adb shell

改变网卡网址

ifconfig eth0 192.168.0.167 up

添加虚拟网卡

ifconfig eth0:0 192.168.10.10 up

以上的命令就可以在eth0网卡上创建一个叫eth0:0的虚拟网卡,他的地址是:192.168.10.10

删除虚拟网卡

ifconfig eth0:0 down

ip route 查看路由表的内容

G8142:/ $ ip route
192.168.31.0/24 dev wlan0  proto kernel  scope link  src 192.168.31.165

ip rule 显示当前路由策略

Android设备中可以使用命令ip rule显示现有的路由策略，如下所示：rk3399_all:/ # ip rule
0:     from all lookup local
10000:  from all to 172.29.7.148 lookup eth0
10000:  from all fwmark 0xc0000/0xd0000 lookup legacy_system
10500:  from all iif lo oif dummy0 uidrange 0-0 lookup dummy0
10500:  from all iif lo oif eth0 uidrange 0-0 lookup eth0
13000:  from all fwmark 0x10063/0x1ffff iif lo lookup local_network
13000:  from all fwmark 0x10064/0x1ffff iif lo lookup eth0
14000:  from all iif lo oif dummy0 lookup dummy0
14000:  from all iif lo oif eth0 lookup eth0
15000:  from all fwmark 0x0/0x10000 lookup legacy_system
16000:  from all fwmark 0x0/0x10000 lookup legacy_network
17000:  from all fwmark 0x0/0x10000 lookup local_network
19000:  from all fwmark 0x64/0x1ffff iif lo lookup eth0
22000:  from all fwmark 0x0/0xffff iif lo lookup eth0
23000:  from all fwmark 0x0/0xffff uidrange 0-0 lookup main
32000:  from all unreachable
rk3399_all:/ #其中第一列表示策略号码（同时也是策略对应的索引值），可支持上万条策略，
策略号码数值越小表示该条策略的优先级越高。策略0为优先级最高的策略，
在数据包进行路由时，首先匹配该数据包是否满足策略0的规则，
即所有的数据包去 local路由表中去查找自己的路由方向，
没有找到则使用下一优先级的路由策略，这里为10000号策略，
即所有的数据包发往172.29.7.148的都从eth0网卡出去。rk3399_all:/ # ip route list table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 172.29.0.0 dev eth0 proto kernel scope link src 172.29.7.28
local 172.29.7.28 dev eth0 proto kernel scope host src 172.29.7.28
broadcast 172.29.255.255 dev eth0 proto kernel scope link src 172.29.7.28
rk3399_all:/ #

130|G8142:/ $ ip rule ls
0:      from all lookup local
10000:  from all fwmark 0xc0000/0xd0000 lookup 99
10500:  from all oif dummy0 uidrange 0-0 lookup 1003
10500:  from all oif wlan0 uidrange 0-0 lookup 1023
13000:  from all fwmark 0x10063/0x1ffff lookup 97
13000:  from all fwmark 0x10064/0x1ffff lookup 1023
14000:  from all oif dummy0 lookup 1003
14000:  from all oif wlan0 lookup 1023
15000:  from all fwmark 0x0/0x10000 lookup 99
16000:  from all fwmark 0x0/0x10000 lookup 98
17000:  from all fwmark 0x0/0x10000 lookup 97
19000:  from all fwmark 0x64/0x1ffff lookup 1023
22000:  from all fwmark 0x0/0xffff lookup 1023
23000:  from all fwmark 0x0/0xffff uidrange 0-0 lookup main
32000:  from all unreachable

路由策略数据库管理命令

G8142:/ $ ip route
192.168.31.0/24 dev wlan0  proto kernel  scope link  src 192.168.31.165G8142:/ $ ifconfig
wlan0     Link encap:UNSPEC    Driver icnssinet addr:192.168.31.165  Bcast:192.168.31.255  Mask:255.255.255.0inet6 addr: fe80::86c7:eaff:fe2d:b98/64 Scope: LinkUP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1RX packets:6644 errors:0 dropped:0 overruns:0 frame:0TX packets:6980 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:3000RX bytes:6001248 TX bytes:1155447

kuznet@amber:~ $ ip ru ls0: from all lookup local200: from 192.203.80.0/24 to 193.233.7.0/24 lookup main210: from 192.203.80.0/24 to 192.203.80.0/24 lookup main220: from 192.203.80.0/24 lookup inr.ruhep realms inr.ruhep/radio-msu300: from 193.233.7.83 to 193.233.7.0/24 lookup main310: from 193.233.7.83 to 192.203.80.0/24 lookup main320: from 193.233.7.83 lookup inr.ruhep map-to 192.203.80.14432766: from all lookup mainkuznet@amber:~ $每行第一部分的数字是规则的优先级，接着是选择符。关键词lookup后面接着路由表识别符。如果规则要进行网络地址转换，还需要一个关键词map-to设置转换以后的地址。上面的示例非常简单，192.203.80.0/24和193.233.7.0/24组成内部网络，但是它们向外发送数据包要通过不同的路由。主机193.233.7.83和外界会话时，地址需要转换为192.203.80.144。

查看路由表

最早的策略配置方式是写了个shell脚本，配置了如下策略，对于目的IP为77/78的都走eth0网卡。在init.rc中开启对应的服务ipruleservice，网卡启动或者链路有变化调用该服务配置策略，ipruleservice中命令如下

ip rule add to 192.168.1.78 table eth0
ip rule add to 192.168.1.77 table eth0

APP 实际应用

public static final int TRANSPORT_BLUETOOTH = 2;
public static final int TRANSPORT_CELLULAR = 0;
public static final int TRANSPORT_ETHERNET = 3;
public static final int TRANSPORT_LOWPAN = 6;
public static final int TRANSPORT_USB = 8;
public static final int TRANSPORT_VPN = 4;
public static final int TRANSPORT_WIFI = 1;
public static final int TRANSPORT_WIFI_AWARE = 5;

考虑一个特殊的需求，某app只能通过WIFI接口去传输数据，是否可以实现？较新版本的android已经支持了该功能，通过调用setProcessDefaultNetwork()可以指定某一进程的网络接口，

该进程在创建socket时(app首先调用setProcessDefaultNetwork())，android底层会利用setsockopt函数设置该socket的SO_MARK为netId（android有自己的管理逻辑，每个Network有对应的ID），以后利用该socket发送的数据都会被打上netId的标记(fwmark 值)