--- -- Buffered network I/O helper functions. -- -- The functions in this module can be used for delimiting data received by the -- nmap.receive_buf function in the Network I/O API (which see). -- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html local stdnse = require "stdnse" local find = (require "string").find _ENV = stdnse.module("match", stdnse.seeall) --various functions for use with NSE's nsock:receive_buf - function -- e.g. -- sock:receive_buf(numbytes(80), true) - is the buffered version of -- sock:receive_bytes(80) - i.e. it -- returns exactly 80 bytes and no more --- Return a function that allows delimiting at a certain number of bytes. -- -- This function can be used to get a buffered version of -- sock:receive_bytes(n) in case a script requires more than one -- fixed-size chunk, as the unbuffered version may return more bytes than -- requested and thus would require you to do the parsing on your own. -- -- The keeppattern parameter to receive_buf should be set to -- true, otherwise the string returned will be 1 less than -- num -- @param num Number of bytes. -- @usage sock:receive_buf(match.numbytes(80), true) -- @see nmap.receive_buf numbytes = function(num) local n = num return function(buf) if(#buf >=n) then return n, n end return nil end end --- Search for a pattern within a set number of bytes -- -- This function behaves just like passing a pattern to receive_buf, but it -- will only receive a predefined number of bytes before returning the buffer. -- @param pattern The pattern to search for -- @param within The number of bytes to consume -- @usage sock:receive_buf(match.pattern_limit("\r\n", 80), true) pattern_limit = function (pattern, within) local n = within return function(buf) local left, right = find(buf, pattern) if left then return left, right elseif #buf >= n then return n, n end return nil end end return _ENV;