Fix the first round of HTTP pipeline requests. The pipeline makes an

initial request to get a value stored in the Keep-Alive header, which is
the size of the pipeline. It then iterates, doignt hat many requests at
once until the list of requests is exhausted. The prbolem was that in
the first round, it didn't count its initial Keep-Alive probe. So if the
server said it was good for 40 requests, we would send 41 before closing
the connection. Even worse was when the initial probe returned a
"Connection: close"; the pipeline would try another request before
closing the connection for the first time.

nselib/http.lua

@@ -1141,21 +1141,21 @@ pipeline = function(host, port, allReqs)
   responses[#responses + 1] = response
 
   local limit = getPipelineMax(response)
+  local count = 1
   stdnse.print_debug("Number of requests allowed by pipeline: " .. limit)
 
   while #responses < #allReqs do
-    local j, batch_begin, batch_end
+    local j, batch_end
     -- we build a big string with many requests, upper limited by the var "limit"
     local requests = ""
 
-    batch_begin = #responses + 1
     if #responses + limit < #allReqs then
       batch_end = #responses + limit
     else
       batch_end = #allReqs
     end
 
-    j = batch_begin
+    j = #responses + 1
     while j <= batch_end do
       if j == batch_end then
         allReqs[j].opts.header["Connection"] = "close"
@@ -1165,9 +1165,10 @@ pipeline = function(host, port, allReqs)
     end
 
     -- Connect to host and send all the requests at once!
-    if not socket:get_info() then
+    if count >= limit or not socket:get_info() then
       socket:connect(host.ip, port.number, bopt)
       partial = ""
+      count = 0
     end
     socket:set_timeout(10000)
     socket:send(requests)
@@ -1177,18 +1178,18 @@ pipeline = function(host, port, allReqs)
       if not response then
         break
       end
+      count = count + 1
       responses[#responses + 1] = response
     end
 
     socket:close()
-    partial = ""
 
-    if #responses + 1 == batch_begin then
+    if count == 0 then
       stdnse.print_debug("Received 0 of %d expected reponses.\nGiving up on pipeline.", limit);
       break
-    elseif #responses < batch_end then
-      stdnse.print_debug("Received only %d of %d expected reponses.\nDecreasing max pipelined requests to %d.", #responses + 1 - batch_begin, limit, #responses + 1 - batch_begin)
-      limit = #responses + 1 - batch_begin
+    elseif count < limit then
+      stdnse.print_debug("Received only %d of %d expected reponses.\nDecreasing max pipelined requests to %d.", count, limit, count)
+      limit = count
     end
   end