Commit cacdc27f authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

low-speed-limit: avoid timeout flood 

Introducing Curl_expire_latest(). To be used when we the code flow only
wants to get called at a later time that is "no later than X" so that
something can be checked (and another timeout be added).

The low-speed logic for example could easily be made to set very many
expire timeouts if it would be called faster or sooner than what it had
set its own timer and this goes for a few other timers too that aren't
explictiy checked for timer expiration in the code.

If there's no condition the code that says if(time-passed >= TIME), then
Curl_expire_latest() is preferred to Curl_expire().

If there exists such a condition, it is on the other hand important that
Curl_expire() is used and not the other.

Bug: http://curl.haxx.se/mail/lib-2014-06/0235.html
Reported-by: Florian Weimer
parent 09b5a998

lib/asyn-ares.c

+1 −1
Original line number Diff line number Diff line
@@ -235,7 +235,7 @@ int Curl_resolver_getsock(struct connectdata *conn, 
  milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000);

  if(milli == 0)

    milli += 10;

  Curl_expire(conn->data, milli);

  Curl_expire_latest(conn->data, milli);



  return max;

}

lib/asyn-thread.c

+1 −1
Original line number Diff line number Diff line
@@ -541,7 +541,7 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn, 
      td->poll_interval = 250;



    td->interval_end = elapsed + td->poll_interval;

    Curl_expire(conn->data, td->poll_interval);

    Curl_expire_latest(conn->data, td->poll_interval);

  }



  return CURLE_OK;

lib/connect.c

+1 −1
Original line number Diff line number Diff line
@@ -1054,7 +1054,7 @@ singleipconnect(struct connectdata *conn, 


  conn->connecttime = Curl_tvnow();

  if(conn->num_addr > 1)

    Curl_expire(data, conn->timeoutms_per_addr);

    Curl_expire_latest(data, conn->timeoutms_per_addr);



  /* Connect TCP sockets, bind UDP */

  if(!isconnected && (conn->socktype == SOCK_STREAM)) {

lib/multi.c

+43 −3
Original line number Diff line number Diff line
@@ -1491,7 +1491,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi, 
                           data->set.buffer_size : BUFSIZE);

        timeout_ms = Curl_sleep_time(data->set.max_send_speed,

                                     data->progress.ulspeed, buffersize);

        Curl_expire(data, timeout_ms);

        Curl_expire_latest(data, timeout_ms);

        break;

      }
@@ -1507,7 +1507,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi, 
                           data->set.buffer_size : BUFSIZE);

        timeout_ms = Curl_sleep_time(data->set.max_recv_speed,

                                     data->progress.dlspeed, buffersize);

        Curl_expire(data, timeout_ms);

        Curl_expire_latest(data, timeout_ms);

        break;

      }
@@ -1569,7 +1569,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi, 


        /* expire the new receiving pipeline head */

        if(data->easy_conn->recv_pipe->head)

          Curl_expire(data->easy_conn->recv_pipe->head->ptr, 1);

          Curl_expire_latest(data->easy_conn->recv_pipe->head->ptr, 1);



        /* Check if we can move pending requests to send pipe */

        Curl_multi_process_pending_handles(multi);
@@ -2682,6 +2682,46 @@ void Curl_expire(struct SessionHandle *data, long milli) 
#endif

}



/*

 * Curl_expire_latest()

 *

 * This is like Curl_expire() but will only add a timeout node to the list of

 * timers if there is no timeout that will expire before the given time.

 *

 * Use this function if the code logic risks calling this function many times

 * or if there's no particular conditional wait in the code for this specific

 * time-out period to expire.

 *

 */

void Curl_expire_latest(struct SessionHandle *data, long milli)

{

  struct timeval *exp = &data->state.expiretime;



  struct timeval set;



  set = Curl_tvnow();

  set.tv_sec += milli/1000;

  set.tv_usec += (milli%1000)*1000;



  if(set.tv_usec >= 1000000) {

    set.tv_sec++;

    set.tv_usec -= 1000000;

  }



  if(exp->tv_sec || exp->tv_usec) {

    /* This means that the struct is added as a node in the splay tree.

       Compare if the new time is earlier, and only remove-old/add-new if it

         is. */

    long diff = curlx_tvdiff(set, *exp);

    if(diff > 0)

      /* the new expire time was later than the top time, so just skip this */

      return;

  }



  /* Just add the timeout like normal */

  Curl_expire(data, milli);

}



CURLMcode curl_multi_assign(CURLM *multi_handle,

                            curl_socket_t s, void *hashp)

{

lib/multiif.h

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
 * Prototypes for library-wide functions provided by multi.c

 */

void Curl_expire(struct SessionHandle *data, long milli);

void Curl_expire_latest(struct SessionHandle *data, long milli);



bool Curl_multi_pipeline_enabled(const struct Curl_multi* multi);

void Curl_multi_handlePipeBreak(struct SessionHandle *data);