TFTP in PSEUDO CODE


use simple server to create and bind socket

while(true)//start listening
{
use receivefrom or read command on socket to listen for data
	 read data into a buffer of size 516 bytes
	 read will wait for this to occur (blocking)

examine the first 4 bytes to get the opcode
     if opcode == RRQ
	       extract file name
	       tries=0;//set flag
	       while(not end of file)	
			 {
			 while(tries < max_retries)
			 {
				fill in header (4 bytes) of buffer[516]
				     give packet sequential number
				read 512 bytes from file
				     (deal with case of exactly 512 bytes)
				insert data into end of buffer[516]
				write buffer[516]to socket
				listen on socket (read[516] )
				if( select()== 2 minutes)  //to implement timeout
					     continue;//resend
				examine the first 4 bytes to get the opcode
				if opcode == AKN
				   if number == sequential number
					     break;
			           else
				     tries++
				     continue;
				else
			            error (ignore it! or exit loop, your choice)
				    continue;
  			  }      			 	       
			  }

     if opcode == WRQ

		  similar to above RRQ



     else
      error;	
      continue while loop//conitiue listening for some new request
}