Ad-hoc wifi

iwconfig eth0 mode ad-hoc
iwconfig eth0 essid whatever
ifconfig eth0 192.168.0.1

on property:init.svc.wpa_supplicant=stopped
    stop dhcpcd

on property:init.svc.dhcpcd=stopped
        dhcpcd -k eth0
# end of wifi

# lsmod
ipt_MASQUERADE 2912 1 - Live 0xbf067000
iptable_nat 4936 1 - Live 0xbf064000
nf_nat 15894 2 ipt_MASQUERADE,iptable_nat, Live 0xbf05f000
nf_conntrack_ipv4 13900 3 iptable_nat,nf_nat, Live 0xbf05a000
nf_conntrack 54912 4 ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4, Live 0xbf04b000
ipt_REJECT 3136 1 - Live 0xbf026000
xt_multiport 3360 0 - Live 0xbf024000
xt_owner 2944 1 - Live 0xbf022000
iptable_filter 3040 1 - Live 0xbf020000
ip_tables 10928 2 iptable_nat,iptable_filter, Live 0xbf01c000
x_tables 13896 6 ipt_MASQUERADE,iptable_nat,ipt_REJECT,xt_multiport,xt_owner,ip_tables, Live 0xbf017000

(Standard-Module:)
bcm4325 135600 0 - Live 0xbf028000
multipdp 13408 2 - Live 0xbf012000
dpram 67384 6 - Live 0xbf000000

cat /etc/iftab
wlan mac xx:xx:xx:xx:xx:xx

ifconfig eth0 down
ifrename
iwconfig wlan mode ad-hoc
iwconfig wlan essid whatever
ifconfig wlan 192.168.0.1
echo 1 >/proc/sys/net/ipv4/ip_forward

Edit: natürlich das wichtigste vergessen...
iptables -t nat -A POSTROUTING -j MASQUERADE

$ su -c "/system/bin/wpa_cli -p /data/misc/wifi/"
wpa_cli v0.5.10                                  
Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi> and contributors

This program is free software. You can distribute it and/or modify it
under the terms of the GNU General Public License version 2.         

Alternatively, this software may be distributed under the terms of the
BSD license. See README and COPYING for more details.                 


Selected interface 'eth0'

Interactive mode

> 
<2>CTRL-EVENT-SCAN-RESULTS  Ready
scan_results                     
bssid / frequency / signal level / flags / ssid
00:16:38:e6:38:31       2412    -49     [WPA2-PSK-TKIP+CCMP]    Sven-Ola
00:16:38:e6:38:31       2412    -50     [WPA2-PSK-TKIP+CCMP]    Sven-Ola
02:ca:ff:ee:ba:be       2457    -40     [IBSS]          olsr.freifunk.net
>                                                                        
<2>CTRL-EVENT-SCAN-RESULTS  Ready                                        
add_network                                                              
2                                                                        
>                                                                        
<2>CTRL-EVENT-SCAN-RESULTS  Ready                                        
set_network 2 mode 1                                                     
OK                                                                       
> set_network 2 ssid "olsr.freifunk.net"                                 
OK                                                                       
> set_network 2 bssid 02:ca:ff:ee:ba:be                                  
OK                                                                       
> set_network 2 frequency 2457                                           
OK                                                                       
> set_network 2 key_mgmt NONE                                            
OK                                                                       
> enable_network 2                                                       
OK                                                                       
> ap_scan 2                                                              
<2>CTRL-EVENT-SCAN-RESULTS  Ready                                        
OK                                                                       
> select_network 2                                                       
OK                                                                       
<2>CTRL-EVENT-STATE-CHANGE id=1 state=0                                  
>
<2>CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
<2>CTRL-EVENT-STATE-CHANGE id=-1 state=0
<2>CTRL-EVENT-STATE-CHANGE id=-1 state=2
<2>Trying to associate with SSID 'olsr.freifunk.net'
<2>CTRL-EVENT-STATE-CHANGE id=-1 state=3
<2>CTRL-EVENT-STATE-CHANGE id=2 state=4
<2>Associated with 02:ca:ff:ee:ba:be
<2>CTRL-EVENT-STATE-CHANGE id=2 state=7
<2>CTRL-EVENT-CONNECTED - Connection to 02:ca:ff:ee:ba:be completed (reauth) [id=2 id_str=]

<2>CTRL-EVENT-SCAN-RESULTS  Ready

<2>CTRL-EVENT-STATE-CHANGE id=2 state=8
<2>CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
<2>CTRL-EVENT-STATE-CHANGE id=-1 state=8

<2>CTRL-EVENT-STATE-CHANGE id=-1 state=2

<2>CTRL-EVENT-SCAN-RESULTS  Ready

<2>CTRL-EVENT-SCAN-RESULTS  Ready

root@galaxy:/# ifconfig eth0 104.198.65.66
root@galaxy:/# iwconfig
lo        no wireless extensions.

eth0      IEEE 802.11-DS  ESSID:"olsr.freifunk.net"  Nickname:""
          Mode:Ad-Hoc  Frequency:2.457 GHz  Cell: 02:CA:FF:EE:BA:BE
          Bit Rate=54 Mb/s   Tx-Power:32 dBm
          Retry min limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Managementmode:All packets received
          Link Quality=5/5  Signal level=-39 dBm  Noise level=-92 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

root@galaxy:/# ping 104.198.65.65
PING 104.198.65.65 (104.198.65.65) 56(84) bytes of data.
64 bytes from 104.198.65.65: icmp_seq=1 ttl=64 time=19.1 ms
^C
--- 104.198.65.65 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 1ms
rtt min/avg/max/mdev = 19.190/19.190/19.190/0.000 ms
root@galaxy:/# wget -O /dev/null http://104.198.65.65/cgi-bin-dev-zero.bin
--2009-09-13 10:27:19--  http://104.198.65.65/cgi-bin-dev-zero.bin
Connecting to 104.198.65.65:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/octet-stream]
Saving to: `/dev/null'

    [                 <=>                   ] 13,269,256  1.21M/s              ^C

#!/system/bin/sh

# Fixed IP config, use ADR=dhcp otherwise
ADR=104.198.65.66
MSK=255.0.0.0
DNS=67.223.248.57

# Wifi config, BSSID seems to be required. Use "r" command to show scan_results
# Do "iwlist wlan0 freq" on PC for channel list, ch1=2412, ch11=2462, ch13=2472
ESSID="olsr.freifunk.net"
BSSID="02:ca:ff:ee:ba:be"
FREQU=2457

# Neighbour for ping test ("P" command)
NEIGH=104.198.65.65

DEV=eth0

# Note: the /system/bin/sh has no test command
# so we use "case;easc" instead of "if;then;fi"

timer () {
  case "$time" in
    0)return 1;;
  esac
  time=$((time-1))
}

pidof () {
  for cmd in /proc/*/cmdline
  do
    case "$(cat $cmd)" in
      $1*)
        pid=${cmd#/proc/}
        echo ${pid%%/*}
	return
      ;;
    esac
  done
}

state () {
  for i in $(wpa_cli -i $DEV -p /data/misc/wifi status)
  do
    case "$i" in
      wpa_state=*)echo ${i#*=};;
    esac
  done
}

# returns network number, creates new entry if ssid unknown

getnetnum () {
  ssid=$1
  net=none
  IFS="
"
  for i in $(wpa_cli -i $DEV -p /data/misc/wifi list_network)
  do
    unset IFS
    set $i
    case "$2" in
      $ssid)net=$1;;
    esac
  done
  case "$net" in
    none)
      net=$(wpa_cli -i $DEV -p /data/misc/wifi add_network)
    ;;
  esac
  echo $net
}

# ssid bssid frequency

adhoc () {
  net=$(getnetnum $1)
  pid=$(getprop dhcp.$DEV.pid)
  cmd=$(cat /proc/$pid/cmdline 2>&-)

  # Note: saved /data/misc/wifi/bcm_supp.conf not sufficient for function
  # We always need to (re-)set the parameters with the following commands.

  wpa_cli -i $DEV -p /data/misc/wifi set_network $net mode 1 >&-
  wpa_cli -i $DEV -p /data/misc/wifi set_network $net ssid \"$1\" >&-
  wpa_cli -i $DEV -p /data/misc/wifi set_network $net bssid $2 >&-
  wpa_cli -i $DEV -p /data/misc/wifi set_network $net frequency $3 >&-
  wpa_cli -i $DEV -p /data/misc/wifi set_network $net key_mgmt NONE >&-
  wpa_cli -i $DEV -p /data/misc/wifi enable_network $net >&-
  wpa_cli -i $DEV -p /data/misc/wifi ap_scan 2 >&-
  wpa_cli -i $DEV -p /data/misc/wifi select_network $net >&-

  time=5
  while timer
  do
    state=$(state)
    case "$state" in
      COMPLETED)time=0;;
      DISCONNECTED|ASSOCIATING)sleep 1;;
      *)
        echo "Error: state is $state" 2>&-
        exit 1
      ;;
    esac
  done

  echo $state
  case "$state" in
    COMPLETED);;
    *)exit 1;;
  esac

  case "$ADR" in
    dhcp|DHCP);;
    *)
      # Using a fixed IP config
      case "$cmd" in
        /system/bin/dhcpcd-*)
          # Active dhcpcd, wpa_supp starts new dhcpcd, wait for that
          time=5
          while timer
          do
            case "$(getprop dhcp.$DEV.pid)" in
              $pid)sleep 1;;
              *)time=0;;
            esac
          done
        ;;
      esac

      case "$(cat /proc/$(getprop dhcp.$DEV.pid)/cmdline 2>&-)" in
        /system/bin/dhcpcd-*)
          echo "Stopping dhcpcd ($(getprop dhcp.$DEV.pid))"
          kill $(getprop dhcp.$DEV.pid)
        ;;
      esac

      # Fake a running dhcpcd
      setprop dhcp.$DEV.pid $(pidof /system/bin/wpa_supplicant)
      setprop init.svc.dhcpcd running

      setprop dhcp.$DEV.ipaddress $ADR
      setprop dhcp.$DEV.mask $MSK
      setprop dhcp.$DEV.dns1 $DNS
      ifconfig $DEV $(getprop dhcp.$DEV.ipaddress) netmask $(getprop dhcp.$DEV.mask)
      setprop dhcp.$DEV.reason BOUND
      setprop dhcp.$DEV.result ok
    ;;
  esac
  echo "Ok."
}

case "$1" in
  l)
    wpa_cli -i $DEV -p /data/misc/wifi list_network
  ;;
  o)
    shift
    /data/local/bin/olsrd $*
  ;;
  O)
    kill $(pidof /data/local/bin/olsrd)
    kill -9 $(pidof /data/local/bin/olsrd)
  ;;
  p)
    ping 151.1.1.1
  ;;
  P)
    ping $NEIGH
  ;;
  s)
    wpa_cli -i $DEV -p /data/misc/wifi status
  ;;
  S)
    wpa_cli -i $DEV -p /data/misc/wifi config_save
  ;;
  [0-9])
    wpa_cli -i $DEV -p /data/misc/wifi select_network $1
  ;;
  w)
    wpa_cli -i $DEV -p /data/misc/wifi
  ;;
  h)
    cat<<EOF
Script to connect to wireless lan in ad-hoc (IBSS) mode.
The following single char commands are available:

l	lists configured network entries
o	starts olsrd (ad-hoc routing daemon)
O	stops olsrd (ad-hoc routing daemon)
p	ping test to internet (ctrl-c to stop)
P	ping test to neighbour (ctrl-c to stop)
s	shows current wpa_supplicant status
S	save config, adds adhoc entry to java wifi settings
[num]	manually activate network by number
w	interactively use wpa_cli command line
h	show this help.
(empty)	start ad-hoc wifi mode

You need to switch Wifi off/on to return to normal operation.

You need superuser rights ("root access") to execute. For this,
you may create a script in /system/bin to callup this script,
e.g. su -c "$0 \$*" (with quotes as shown!)
EOF
  ;;
  *)
    adhoc $ESSID $BSSID $FREQU
  ;;
esac

exit 0

ifrename
iwconfig wlan mode ad-hoc
iwconfig wlan essid whatever