From 7176a85cd48d37bc068312ffa79f254305cf4511 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Mon, 14 Mar 2016 17:57:22 +0100 Subject: [PATCH] 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 --- 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 f046a3b79..31bc11dc0 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) {