Imported Upstream version 1.17.1upstream/1.17.1

Change-Id: Ifb18ec521bbeaf8bac560e0588657f136ca93e5d

1 files changed, 59 insertions, 0 deletions

diff --git a/src/lib/ares_fds.c b/src/lib/ares_fds.c
new file mode 100644
index 0000000..f405fc0
--- /dev/null
+++ b/src/lib/ares_fds.c
@@ -0,0 +1,59 @@
+
+/* Copyright 1998 by the Massachusetts Institute of Technology.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting
+ * documentation, and that the name of M.I.T. not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ */
+
+#include "ares_setup.h"
+
+#include "ares.h"
+#include "ares_nowarn.h"
+#include "ares_private.h"
+
+int ares_fds(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
+{
+  struct server_state *server;
+  ares_socket_t nfds;
+  int i;
+
+  /* Are there any active queries? */
+  int active_queries = !ares__is_list_empty(&(channel->all_queries));
+
+  nfds = 0;
+  for (i = 0; i < channel->nservers; i++)
+    {
+      server = &channel->servers[i];
+      /* We only need to register interest in UDP sockets if we have
+       * outstanding queries.
+       */
+      if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
+        {
+          FD_SET(server->udp_socket, read_fds);
+          if (server->udp_socket >= nfds)
+            nfds = server->udp_socket + 1;
+        }
+      /* We always register for TCP events, because we want to know
+       * when the other side closes the connection, so we don't waste
+       * time trying to use a broken connection.
+       */
+      if (server->tcp_socket != ARES_SOCKET_BAD)
+       {
+         FD_SET(server->tcp_socket, read_fds);
+         if (server->qhead)
+           FD_SET(server->tcp_socket, write_fds);
+         if (server->tcp_socket >= nfds)
+           nfds = server->tcp_socket + 1;
+	}
+    }
+  return (int)nfds;
+}