Commit 54ca7d8c authored by Steinar H. Gunderson's avatar Steinar H. Gunderson
Browse files

Don't skip a server if it's the only one. (Bugfix from the Google tree.)

parent 0819c3a8

ares/ares_process.c

+23 −5
Original line number Diff line number Diff line
@@ -65,6 +65,8 @@ static void process_timeouts(ares_channel channel, time_t now); 
static void process_answer(ares_channel channel, unsigned char *abuf,

                           int alen, int whichserver, int tcp, time_t now);

static void handle_error(ares_channel channel, int whichserver, time_t now);

static void skip_server(ares_channel channel, struct query *query,

                        int whichserver);

static struct query *next_server(ares_channel channel, struct query *query, time_t now);

static int open_tcp_socket(ares_channel channel, struct server_state *server);

static int open_udp_socket(ares_channel channel, struct server_state *server);
@@ -474,7 +476,7 @@ static void process_answer(ares_channel channel, unsigned char *abuf, 
    {

      if (rcode == SERVFAIL || rcode == NOTIMP || rcode == REFUSED)

        {

          query->skip_server[whichserver] = 1;

          skip_server(channel, query, whichserver);

          if (query->server == whichserver)

            next_server(channel, query, now);

          return;
@@ -506,12 +508,28 @@ static void handle_error(ares_channel channel, int whichserver, time_t now) 
      next = query->next;

      if (query->server == whichserver)

        {

          query->skip_server[whichserver] = 1;

          skip_server(channel, query, whichserver);

          next = next_server(channel, query, now);

        }

    }

}



static void skip_server(ares_channel channel, struct query *query,

                        int whichserver) {

  /* The given server gave us problems with this query, so if we have

   * the luxury of using other servers, then let's skip the

   * potentially broken server and just use the others. If we only

   * have one server and we need to retry then we should just go ahead

   * and re-use that server, since it's our only hope; perhaps we

   * just got unlucky, and retrying will work (eg, the server timed

   * out our TCP connection just as we were sending another request).

   */

  if (channel->nservers > 1)

    {

      query->skip_server[whichserver] = 1;

    }

}



static struct query *next_server(ares_channel channel, struct query *query, time_t now)

{

  /* Advance to the next server or try. */
@@ -553,7 +571,7 @@ void ares__send_query(ares_channel channel, struct query *query, time_t now) 
        {

          if (open_tcp_socket(channel, server) == -1)

            {

              query->skip_server[query->server] = 1;

              skip_server(channel, query, query->server);

              next_server(channel, query, now);

              return;

            }
@@ -583,7 +601,7 @@ void ares__send_query(ares_channel channel, struct query *query, time_t now) 
        {

          if (open_udp_socket(channel, server) == -1)

            {

              query->skip_server[query->server] = 1;

              skip_server(channel, query, query->server);

              next_server(channel, query, now);

              return;

            }
@@ -591,7 +609,7 @@ void ares__send_query(ares_channel channel, struct query *query, time_t now) 
      if (swrite(server->udp_socket, query->qbuf, query->qlen) == -1)

        {

          /* FIXME: Handle EAGAIN here since it likely can happen. */

          query->skip_server[query->server] = 1;

          skip_server(channel, query, query->server);

          next_server(channel, query, now);

          return;

        }