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[newlib-cygwin] cygwin_getaddrinfo: workaround Winsock getaddrinfo issue with broken DNS
- From: Corinna Vinschen <corinna at sourceware dot org>
- To: cygwin-cvs at sourceware dot org
- Date: 14 Mar 2016 16:57:38 -0000
- Subject: [newlib-cygwin] cygwin_getaddrinfo: workaround Winsock getaddrinfo issue with broken DNS
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=7176a85cd48d37bc068312ffa79f254305cf4511
commit 7176a85cd48d37bc068312ffa79f254305cf4511
Author: Corinna Vinschen <corinna@vinschen.de>
Date: Mon Mar 14 17:57:22 2016 +0100
cygwin_getaddrinfo: workaround Winsock getaddrinfo issue with broken DNS
Add experimental code to workaround the issue described in the thread
starting at
https://cygwin.com/ml/cygwin/2015-07/msg00350.html
There's a hint in https://communities.vmware.com/message/2577858#2577858
that this problem is related to using the AI_ALL flag.
This patch checks if GetAddrInfoW returned with WSANO_RECOVERY and if
the AI_ALL flag was set, it retries GetAddrInfo without the AI_ALL flag.
* net.cc (cygwin_getaddrinfo): Add experimental code to retry
GetAddrInfoW without AI_ALL flag if it returned with WSANO_RECOVERY.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Diff:
---
winsup/cygwin/net.cc | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/winsup/cygwin/net.cc b/winsup/cygwin/net.cc
index f046a3b..31bc11d 100644
--- a/winsup/cygwin/net.cc
+++ b/winsup/cygwin/net.cc
@@ -3595,7 +3595,16 @@ cygwin_getaddrinfo (const char *hostname, const char *servname,
}
/* Disable automatic IDN conversion on W8 and later. */
whints.ai_flags |= AI_DISABLE_IDN_ENCODING;
- ret = w32_to_gai_err (GetAddrInfoW (whost, wserv, &whints, &wres));
+ ret = GetAddrInfoW (whost, wserv, &whints, &wres);
+ /* Try to workaround an apparent shortcoming in Winsock's getaddrinfo
+ implementation. See this link for details:
+ https://communities.vmware.com/message/2577858#2577858 */
+ if (ret == WSANO_RECOVERY && (whints.ai_flags & AI_ALL))
+ {
+ whints.ai_flags &= ~AI_ALL;
+ ret = GetAddrInfoW (whost, wserv, &whints, &wres);
+ }
+ ret = w32_to_gai_err (ret);
/* Always copy over to self-allocated memory. */
if (!ret)
{