Add nmap.clock() for providing scripts with the current time in floating

point seconds since the epoch, and add clock_ms() and clock_us() to stdnse
for convenience (millisecond and microsecond).

qscan.nse now provides microsecond resolution.

CHANGELOG

@@ -3,9 +3,16 @@
 o [NSE] When receiving raw packets from Pcap, the packet capture time
   is now available to scripts as an additional return value from
   pcap_receive().  It is returned as the floating point number of
-  seconds since the epoch.  The qscan.nse script was updated to use
-  this more accurate data instead of using the clock_ms() function
-  (which returns the current time). [Kris]
+  seconds since the epoch. [Kris]
+
+o [NSE] Added the nmap.clock() function which returns the current time
+  as floating point seconds since the epoch.  Convenience functions
+  clock_ms() and clock_us() were added to stdnse to return the current
+  time in milliseconds and microseconds, respectively. [Kris]
+
+o [NSE] The qscan.nse script was updated to use the more accurate
+  timing data from pcap_receive() and clock() to provide microsecond
+  resolution for round-trip times. [Kris]
 
 o [Zenmap] Fixed a crash that would happen after opening the search
   window, entering a relative date criterion such as "after:-7", and

nse_nmaplib.cc

@@ -177,6 +177,15 @@ static int l_clock_ms (lua_State *L)
   return 1;
 }
 
+static int l_clock (lua_State *L)
+{
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  /* floating point seconds since Epoch */
+  lua_pushnumber(L, TIMEVAL_SECS(tv));
+  return 1;
+}
+
 /* The actual mutex returned by the nmap.mutex function.
  * This function has 4 upvalues:
  * (1) Table (array) of waiting threads.
@@ -672,6 +681,7 @@ int luaopen_nmap (lua_State *L)
     {"new_dnet", l_dnet_new},
     {"get_interface_link", l_dnet_get_interface_link},
     {"clock_ms", l_clock_ms},
+    {"clock", l_clock},
     {"log_write", l_log_write},
     {"new_try", l_new_try},
     {"verbosity", l_get_verbosity},

nse_nsock.cc

@@ -1823,7 +1823,7 @@ int ncap_restore_lua(ncap_request * nr)
     lua_pushnumber(L, nr->packetsz);
     lua_pushlstring(L, (char *) nr->r_layer2, nr->r_layer2_len);
     lua_pushlstring(L, (char *) nr->r_layer3, nr->r_layer3_len);
-    lua_pushnumber(L, (double) nr->recvtime.tv_sec + (double) nr->recvtime.tv_usec / 1000000);
+    lua_pushnumber(L, TIMEVAL_SECS(nr->recvtime));
   } else
   {
     lua_pushnil(L);

nselib/nmap.luadoc

@@ -146,6 +146,12 @@ function set_port_state(host, port, state)
 -- <code>"tcpwrapped"</code>, or <code>"incomplete"</code>.
 function set_port_version(host, port, probestate)
 
+--- Returns the current date and time in seconds.
+-- @return The number of seconds since the epoch (on most systems this is
+-- 01/01/1970) as a floating point value.
+-- @usage local now = nmap.clock()
+function clock()
+
 --- Returns the current date and time in milliseconds.
 -- @return The number of milliseconds since the epoch (on most systems this is
 -- 01/01/1970).

nselib/stdnse.lua

@@ -389,6 +389,18 @@ function format_difftime(t2, t1)
   return sign .. s
 end
 
+--- Returns the current time in milliseconds since the epoch
+-- @return The current time in milliseconds since the epoch
+function clock_ms()
+	return nmap.clock() * 1000
+end
+
+--- Returns the current time in microseconds since the epoch
+-- @return The current time in microseconds since the epoch
+function clock_us()
+	return nmap.clock() * 1000000
+end
+
 ---Get the indentation symbols at a given level. 
 local function format_get_indent(indent, at_end)
 	local str = ""

scripts/qscan.nse

@@ -29,13 +29,14 @@ description = [[
 --
 -- @output
 -- | qscan:
--- | PORT  FAMILY  MEAN (ms)  STDDEV  LOSS (%)
--- | 21    0       2.70       1.25    0.0%
--- | 22    0       2.50       0.53    0.0%
--- | 23    1       4.80       0.63    0.0%
--- | 25    0       2.40       0.52    0.0%
--- | 80    0       2.40       0.70    0.0%
--- |_443   0       2.40       0.52    0.0%
+-- | PORT  FAMILY  MEAN (us)  STDDEV  LOSS (%)
+-- | 21    0       2082.70    460.72  0.0%
+-- | 22    0       2211.70    886.69  0.0%
+-- | 23    1       4631.90    606.67  0.0%
+-- | 24    0       1922.40    336.90  0.0%
+-- | 25    0       2017.30    404.31  0.0%
+-- | 80    1       4180.80    856.98  0.0%
+-- |_443   0       2013.30    368.91  0.0%
 -- 
 
 -- 03/17/2010
@@ -46,6 +47,7 @@ license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
 
 categories = {"safe", "discovery"}
 
+require 'stdnse'
 require 'bin'
 require 'packet'
 require 'tab'
@@ -229,7 +231,7 @@ local report = function(stats)
 
 	tab.add(outtab, 1, "PORT")
 	tab.add(outtab, 2, "FAMILY")
-	tab.add(outtab, 3, "MEAN (ms)")
+	tab.add(outtab, 3, "MEAN (us)")
 	tab.add(outtab, 4, "STDDEV")
 	tab.add(outtab, 5, "LOSS (%)")
 
@@ -404,7 +406,7 @@ action = function(host)
 
 			pcap:pcap_register(bin.pack('AA=S=S', tcp.ip_bin_src, tcp.ip_bin_dst, tcp.tcp_sport, tcp.tcp_dport))
 
-			start = nmap.clock_ms()
+			start = stdnse.clock_us()
 
 			try(sock:ip_send(tcp.buf))
 
@@ -414,10 +416,10 @@ action = function(host)
 
 			if not stop then
 				-- probably a timeout, just grab current time
-				stop = nmap.clock_ms()
+				stop = stdnse.clock_us()
 			else
-				-- we gotta use msecs
-				stop = stop * 1000
+				-- we use usecs
+				stop = stop * 1000000
 			end
 
 			rtt = stop - start