TFTP Server?

Ok, got the enconding figured out (I ripped it straight from the Tcl wiki). Here's the latest version.

  
 when CLIENT_ACCEPTED {   
      log local0. "Client connected from [IP::client_addr]"   
           binary scan [UDP::payload] xc opcode   
      log local0. "Opcode is $opcode"   
  
 if { $opcode == 1 } {   
      binary scan [UDP::payload] xxa* string   
      log local0. "String is $string"   
      set stringlist [split $string \000]   
      set file [lindex $stringlist 0]   
      set mode [lindex $stringlist 1]   
      log local0. "File is $file, Mode is $mode"   
  
      if { $mode != "octet" && $mode != "netascii" } {   
           reject   
  
      } else {   
           log local0. "Send the file!"   
  
           set data [binary format xcSa* 3  1 [string range $::tftp_file 0 511]]  
           log local0. "data = $data"  
           UDP::respond $data  
           }    
      } else { reject }   
 }  
 

So - incrementing the block ID (the "1" in the format command above) along with moving to the next 512 bytes is all that's left, modulo the changes citizen_elah has added that improve the protocol handling. This is pretty close. This will hopefully let us avoid having to embed the file into the actual rule.