// ip.clickpat

// Patterns for the Click pattern optimizer (click-xform) that change
// common sequences of IP-related elements into single combination elements.

// To transform a router configuration according to these patterns, run
//     % click-xform -p ip.clickpat ROUTER > TRANSFORMED-ROUTER

elementclass IPOutput {
  input -> DropBroadcasts
	-> cp :: PaintTee($paint)
	-> gw :: IPGWOptions($my_ip)
	-> FixIPSrc($my_ip)
	-> dt :: DecIPTTL
	-> fr :: IPFragmenter($mtu)
	-> output;
  cp[1] -> [1]output;
  gw[1] -> [2]output;
  dt[1] -> [3]output;
  fr[1] -> [4]output;
}

elementclass IPOutput_Replacement {
  input -> combo :: IPOutputCombo($paint, $my_ip, $mtu) -> output;
  combo[1] -> [1]output;
  combo[2] -> [2]output;
  combo[3] -> [3]output;
  combo[4] -> fr :: IPFragmenter($mtu) -> [0]output;
  fr[1] -> [4]output;
}


// remove redundant GetIPAddresses
elementclass RedundantGetIPAddress {
  input -> CheckIPHeader($bad_addrs)
	-> GetIPAddress(16)
	-> output;
}

elementclass RedundantGetIPAddress_Replacement {
  input -> CheckIPHeader($bad_addrs)
	-> output;
}


// first, case where no one else gets in at the Strip
elementclass IPInput {
  input -> Paint($paint)
	-> Strip(14)
	-> CheckIPHeader($bad_addrs)
	-> output;
}

elementclass IPInput_Replacement {
  input -> IPInputCombo($paint, $bad_addrs) -> output;
}


// second, case where someone does get in at the Strip
elementclass IPInput2 {
  input -> Paint($paint)
	-> s :: Strip(14)
	-> CheckIPHeader($bad_addrs)
	-> output;
  input[1] -> s;
}

elementclass IPInput2_Replacement {
  input -> IPInputCombo($paint, $bad_addrs) -> output;
  input[1] -> Strip(14)
	-> CheckIPHeader($bad_addrs)
	-> GetIPAddress(16)
	-> output;
}