(*
    Set MTU © RickoKid 2008
    Version 0.1

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*)

set resultList to {}
set curMTU to ""
set OSVer to (do shell script "sw_vers -productVersion")
set tigerSupport to false
set legacySupport to false

if OSVer contains "10.4" or OSVer contains "10.3" or OSVer contains "10.2" or OSVer contains "10.1" or OSVer contains "10.1" then
  if OSVer contains "10.4" then
    set tigerSupport to true
  else
    display dialog "This script has only been tested on Mac OS X 10.4 and above.  You may encounter errors and/or crashes in earlier versions of Mac OS X" buttons {"OK"} default button "OK"
    set legacySupport to true
  end if
  
  set interfaceList to {}
  
  repeat with theInterface in words of (do shell script "ifconfig -lu")
    if theInterface contains "lo0" then
      set interfaceList to interfaceList & {"lo0 Loopback"}
    else if theInterface contains "en1" then
      set interfaceList to interfaceList & {"en1 (AirPort?)"}
    else if theInterface contains "en" then
      set interfaceList to interfaceList & {theInterface & " (Ethernet?)"}
    else if theInterface contains "fw" then
      set interfaceList to interfaceList & {theInterface & " (Firewire?)"}
    else
      set interfaceList to interfaceList & {theInterface}
    end if
  end repeat
else
  -- set interfaceList to paragraphs of (do shell script "networksetup -listallhardwareports | grep -e 'Hardware Port:' | sed 's/^.*: //'")
  tell application "System Events" to set interfaceList to name of every interface of network preferences
end if

set chosenInterface to choose from list interfaceList with prompt ¬
  "Please select the network interface(s) you would like to set the MTU for (or just click OK to select all interfaces):" with title ¬
  "Select Network Interface" with multiple selections allowed and empty selection allowed
if chosenInterface is not false then -- if something is chosen, but not if cancel is clicked.
  if chosenInterface is {} then set chosenInterface to interfaceList
  if (count of chosenInterface) is not 1 then
    set AppleScript's text item delimiters to return
    set newMTU to text returned of (display dialog "Please enter the new MTU value for these interfaces:" & return & return & chosenInterface with title "Set MTU" default answer curMTU)
  end if
  
  repeat with theInterface in chosenInterface
    if legacySupport or tigerSupport then
      set netid to word 1 of theInterface
    else
      set netid to (do shell script "networksetup -listallhardwareports | grep -A1 'Hardware Port: " & theInterface & "$'| tail -n1| sed 's/^.*: //'")
    end if
    if (count of chosenInterface) is 1 then
      set curMTU to last word of (do shell script "ifconfig " & netid & " |grep mtu")
      set newMTU to text returned of (display dialog "Please enter the new MTU value for " & theInterface & ":" with title "Set MTU" default answer curMTU)
    end if
    
    try
      do shell script "ifconfig " & netid & " mtu " & newMTU with administrator privileges and password
      --set theIP to the result
      set resultList to resultList & {"" & theInterface & ":" & tab & "MTU set to " & newMTU & "."}
    on error errorText
      set resultList to resultList & {"" & theInterface & ":" & tab & "Failed to set MTU."}
      --  display dialog ".  Make sure you are connected to the network via " & theInterface & "." with title "DHCP Lookup failure" buttons {"OK"} cancel button "OK" default button "OK"
    end try
    --  display dialog "" & theInterface & " DHCP server: " & theIP buttons {"OK"} default button "OK" with icon 1
  end repeat
  set AppleScript's text item delimiters to return
  if legacySupport then
    display dialog (resultList as text) with title "Set MTU" buttons {"OK"} default button "OK"
  else
    display alert "Set MTU" as informational message (resultList as text) buttons {"OK"} default button "OK"
  end if
end if