New convenience function stdnse.get_timeout

nselib/comm.lua

@@ -10,7 +10,7 @@
 -- * <code>bytes</code> - minimum number of bytes to read.
 -- * <code>lines</code> - minimum number of lines to read.
 -- * <code>proto</code> - string, protocol to use. Default <code>"tcp"</code>
--- * <code>timeout</code> - socket timeout in milliseconds. Default 8000
+-- * <code>timeout</code> - socket timeout in milliseconds. Default: same as <code>stdnse.get_timeout</code>
 -- * <code>connect_timeout</code> - override timeout for connection
 -- * <code>request_timeout</code> - override timeout for requests
 -- * <code>recv_before</code> - boolean, receive data before sending first payload
@@ -169,7 +169,7 @@ end
 -- request_timeout: specific timeout for requests
 -- recv_before: receive data before sending first payload
 --
--- Default timeout is set to 8000.
+-- Default timeout is result of stdnse.get_timeout
 --
 -- @param host The destination host IP
 -- @param port The destination host port
@@ -189,7 +189,7 @@ local function opencon(host, port, protocol, data, opts)
     elseif opts and opts.timeout then
         sd:set_timeout(opts.timeout)
     else
-        sd:set_timeout(8000)
+        sd:set_timeout(stdnse.get_timeout(host))
     end
 
     local status = sd:connect(host, port, protocol)
@@ -205,7 +205,7 @@ local function opencon(host, port, protocol, data, opts)
     elseif opts and opts.timeout then
         sd:set_timeout(opts.timeout)
     else
-        sd:set_timeout(8000)
+        sd:set_timeout(stdnse.get_timeout(host))
     end
 
     local response, early_resp;

nselib/rpc.lua

@@ -163,12 +163,7 @@ Comm = {
     if (not(status)) then
       return status, err
     end
-    timeout = timeout or (
-      -- Use host timeout value * 5 if available
-      (type(host) == "table" and host.times and host.times.timeout * 5)
-      or 10 -- default 10 seconds
-      ) * 1000 -- convert to ms
-    stdnse.debug1("Timeout: %d", timeout)
+    timeout = timeout or stdnse.get_timeout(host, 10000)
     local new_socket = function(...)
       local socket = nmap.new_socket(...)
       socket:set_timeout(timeout)

nselib/stdnse.lua

@@ -1363,5 +1363,40 @@ function contains(tab, item)
   return false, nil
 end
 
+--- Returns a conservative timeout for a host
+--
+-- If the host parameter is a NSE host table with a <code>times.timeout</code>
+-- attribute, then the return value is the host timeout scaled according to the
+-- max_timeout. The scaling factor is defined by a linear formula such that
+-- (max_timeout=8000, scale=2) and (max_timeout=1000, scale=1)
+--
+-- @param host The host object to base the timeout on. If this is anything but
+--             a host table, the max_timeout is returned.
+-- @param max_timeout The maximum timeout in milliseconds. This is the default
+--                    timeout used if there is no host.times.timeout. Default: 8000
+-- @param min_timeout The minimum timeout in milliseconds that will be
+--                    returned. Default: 1000
+-- @return The timeout in milliseconds, suitable for passing to set_timeout
+-- @usage
+-- assert(host.times.timeout == 1.3)
+--  assert(get_timeout() == 8000)
+--  assert(get_timeout(nil, 5000) == 5000)
+--  assert(get_timeout(host) == 2600)
+--  assert(get_timeout(host, 10000, 3000) == 3000)
+function get_timeout(host, max_timeout, min_timeout)
+  max_timeout = max_timeout or 8000
+  local t = type(host) == "table" and host.times and host.times.timeout
+  if not t then
+    return max_timeout
+  end
+  t = t * (max_timeout + 6000) / 7
+  min_timeout = min_timeout or 1000
+  if t < min_timeout then
+    return min_timeout
+  elseif t > max_timeout then
+    return max_timeout
+  end
+  return t
+end
 
 return _ENV;