tftp RRQ basics - can send a file but not retries & ACKS are ignored

git-svn-id: http://svn.code.sf.net/p/netboot65/code@10 93682198-c243-4bdb-bd91-e943c89aac3b

server/netboot65_server.rb

@@ -5,16 +5,17 @@
 # 
 #
 
+Thread.abort_on_exception=true
 
 def log_msg(msg)
-  puts "#{Time.now} #{msg}"
+  puts "#{Time.now.strftime("%Y-%m-%d %H:%M:%S")} #{msg}"
 end
 
 $:.unshift(File.dirname(__FILE__)) unless
 	$:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))
 require 'netboot65_tftp'
 
-bootfile_dir=File.expand_path(File.dirname(__FILE__)+"//..//clients")
+bootfile_dir=File.expand_path(File.dirname(__FILE__)+"//..//boot")
 tftp_server=Netboot65TFTPServer.new(bootfile_dir)
 
 tftp_server.start

server/netboot65_tftp.rb

@@ -7,14 +7,55 @@
 
 require 'socket'
 class Netboot65TFTPServer
+
+  TFTP_OPCODES={
+    1=>'RRQ', #read request
+    2=>'WRQ', #write request
+    3=>'DATA',
+    4=>'ACK',
+    5=>'ERROR',
+  }
+  
+  TFTP_ERRORCODES={
+   1  =>'File not found.',
+   2 =>'Access violation.',
+   3 =>'Disk full or allocation exceeded.',
+   4  =>'Illegal TFTP operation.',
+   5  =>'Unknown transfer ID.',
+   6  =>'File already exists.',
+   7  =>'No such user.',
+  }
+  TFTP_MAX_RESENDS=10
   
   attr_reader :bootfile_dir,:port,:server_thread
-  def initialize(bootfile_dir,port=6969)
+  def initialize(bootfile_dir,port=69)
     @bootfile_dir=bootfile_dir
     @port=port
     @server_thread=nil
+    
   end
   
+  def send_error(client_ip,client_port,error_code,error_msg)
+    packet=[5,error_code,error_msg,0].pack("nnA#{error_msg.length}c")
+    socket=UDPSocket.open.send(packet,0,client_ip,client_port)
+    log_msg("sent error #{error_code}:'#{error_msg}' to #{client_ip}:#{client_port}")
+  end
+  
+  def send_file(client_ip,client_port,filename)
+    
+    client_sock=UDPSocket.open
+    client_sock.connect(client_ip,client_port)
+    data_to_send=File.open(filename,"rb").read
+    blocks_to_send=(data_to_send.length.to_f/512.0).ceil    
+    log_msg("sending #{filename} to #{client_ip}:#{client_port} (#{blocks_to_send} blocks)")
+    blocks_to_send.times do |block_number|
+      block_data=data_to_send[block_number*512,512]
+      packet=[3,block_number+1,block_data].pack("nnA*")
+      log_msg("sending block #{block_number+1}/#{blocks_to_send} to #{client_ip}:#{client_port} - #{block_data.length} bytes")
+      client_sock.send(packet,0,client_ip,client_port)
+    end
+  end
+
   def start()
     log_msg "TFTP: serving #{bootfile_dir} on port #{port}"
     Socket.do_not_reverse_lookup = true
@@ -27,12 +68,33 @@ class Netboot65TFTPServer
         socket.bind(nil,port)
         data,addr_info=socket.recvfrom(4096)
         client_ip=addr_info[3]
-        client_port=addr_info[1]
-        log_msg "TFTP: connect from #{client_ip}:#{client_port}"
+        client_port=addr_info[1]        
+        opcode=data[0,2].unpack("n")[0]
+        opcode_description=TFTP_OPCODES[opcode]
+        opcode_description="[UNK]" if opcode_description.nil?
+        log_msg "TFTP: connect from #{client_ip}:#{client_port} - opcode #{opcode} : #{opcode_description}"
+        case opcode
+          when 1 : #READ REQUEST
+           opcode,filename_and_mode=data.unpack("nA*")
+           filename,mode=filename_and_mode.split(0.chr)
+           log_msg "RRQ for #{filename} (#{mode})"
+           if filename=~/^\./ || filename=~/\.\./ then #looks like something dodgy - either a dotfile or a directory traversal attempt
+            send_error(client_ip,client_port,1,"'#{filename}' invalid") 
+           else
+             full_filename="#{bootfile_dir}/#{filename}"
+             if File.file?(full_filename) then
+               send_file(client_ip,client_port,full_filename)
+            else
+              send_error(client_ip,client_port,1,"'#{filename}' not found") 
+            end
+          end
+          else
+            send_error(client_ip,client_port,4,"opcode #{opcode} not supported")
+          end
         socket.close
       end    
     end
-    #server_thread.join
+#    @server_thread.join
   end
   
   def shutdown()