Implement second fallback mode for DNS requests.

There is some more shardware/software out there which has problems
if two DNS requests are sent using the same tuple

  (source addr, source port, dest addr, dest port)

This can range from firewalls to load balancers.  Some of the vendors
already fixed it in response to this problem.  Still, we need a way
to make glibc work with broken environments.  The single-request-reopen
flag can be used or we fall back automatically to this mode.

1 files changed, 11 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 28b8455569..ff4e26ad67 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2009-06-26  Ulrich Drepper  <drepper@redhat.com>
+
+	* resolv/resolv.h: Define RES_SNGLKUPREOP.
+	* resolv/res_init.c (res_setoptions): Recognize single-request-reopen
+	option.
+	* resolv/res_send.c (reopen): New function.  Broken out of...
+	(send_dg): ... here.  Recognize RES_SNGLKUPREOP.  Implement second
+	fallback mechanism.  If single-request fails switch to
+	single-request-reopen mode which opens a new socket for the second
+	request.
+
 2009-06-25  Andreas Schwab  <aschwab@redhat.com>
 
 	* sysdeps/powerpc/powerpc32/____longjmp_chk.S (LOAD_ARG): Define.