wi fi - How to share Android "Reverse-tethered" internet via Android WiFi?

Before going into main question, we do know that :

Now the question is :

"Is there a way to share the reverse-tethered internet (as we known connected via usb0 interface) via "Android WiFi Hotspot?"

To make it easier, here's the schema:

^{Schema of my setup (click image for larger variant)}

*Additional Notes :

• 
  

  Actually I don't give a limit which version of the Android (so if it's just compatible in higher version e.g. 4.2, it's okay for me), but I prefer it works on 2.3.x (Gingerbread)

  
  


• 
  

  Some explanations of how to make APN (Infrastructure Mode) on Android (just like Wireless Router/[netsh wlan hostednetwork] on Windows 7/8) might be really helpful too.

  
  


• And also some explanations about how to masquerade (internet sharing) between two interfaces in Android. (such as ICS in Windows or Masquerade/iptables thingy in Linux-based)

Answer

I managed to make it work. Here is an "OSI-like" diagram of my setup, if it makes sense:

 ____________________   ______________________________    ____________
|   LinuxVM <----+  |  |                              |  |            |
|  VirtualBox    |  |  |                              |  |            |
| Windows7(host) |  |  | +--> AndroidPhone <-------+  |  | +-->Laptop |
|  (USB)         +-------+   (USB)  (wifi-HotSpot) +-------+   (wifi) |
|___________________|  |______________________________|  |____________|

The script is located at the XDA forum: http://forum.xda-developers.com/showpost.php?p=50236807&postcount=9

## 0.a. Connect android-phone to PC through USB.
## 0.b Enable Settings|...|Tethering 
##  (so that the device gets detected by the PC's kernel, you should see the following with 'dmsg':
##         [    3.976599] rndis_host 1-1:1.0 usb0: register 'rndis_host' at usb-0000:00:0b.0-1, RNDIS device, 4e:d5:8c:7b:4f:5a
## Enable Settings|...|Wifi-Hotspot


## Setup usb reverse-tethering.
#  from: http://forum.xda-developers.com/show....php?t=2287494
#

#  Yours device might be 'rndis0' or something else.  Check by just typing 'netcfg'.
#
netcfg usb0 dhcp
busybox route add default gw 10.42.0.1 dev usb0


## Disable mobile-data.
#
busybox ifconfig rmnet_usb0  0.0.0.0



## Masquerade through USB.
#
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -F
iptables -t nat -A POSTROUTING -o usb0 -j MASQUERADE
iptables -P FORWARD ACCEPT


## Set DNS (if neccessary, ie google's 8.8.4.4).

#
setprop net.dns1 XX.YY.ZZ.WW