From 849a8075c586418645072e99693ba1245fadb4b3 Mon Sep 17 00:00:00 2001
From: Koichiro IWAO <meta@vmeta.jp>
Date: Fri, 28 Oct 2016 17:07:39 +0900
Subject: [PATCH] common: If IPv6 not supported, fall back to IPv4

The system to run xrdp does not necessarily support IPv6 even though
it is compiled with IPv6.

Fixes #432.
---
 common/os_calls.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/common/os_calls.c b/common/os_calls.c
index df08b9e3b4..d8e711b887 100644
--- a/common/os_calls.c
+++ b/common/os_calls.c
@@ -416,11 +416,27 @@ g_tcp_socket(void)
 
 #if defined(XRDP_ENABLE_IPV6)
     rv = (int)socket(AF_INET6, SOCK_STREAM, 0);
+    if (rv < 0)
+    {
+        log_message(LOG_LEVEL_ERROR, "g_tcp_socket: %s", g_get_strerror());
+
+        switch (errno)
+        {
+            case EAFNOSUPPORT: /* if IPv6 not supported, retry IPv4 */
+                log_message(LOG_LEVEL_INFO, "IPv6 not supported, falling back to IPv4");
+                rv = (int)socket(AF_INET, SOCK_STREAM, 0);
+                break;
+
+            default:
+                return -1;
+        }
+    }
 #else
     rv = (int)socket(AF_INET, SOCK_STREAM, 0);
 #endif
     if (rv < 0)
     {
+        log_message(LOG_LEVEL_ERROR, "g_tcp_socket: %s", g_get_strerror());
         return -1;
     }
 #if defined(XRDP_ENABLE_IPV6)