From 26cbd4f43f1f4dad878c02d0a095c2fe9731c44a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stanis=C5=82aw=20Macia=C5=9B?=
 <stanislaw.macias@appeartv.com>
Date: Wed, 23 Dec 2020 12:32:16 +0100
Subject: [PATCH] if_nametoindex function is now used when available

---
 CMakeLists.txt               |  2 ++
 builds/cmake/platform.hpp.in |  1 +
 configure.ac                 | 19 +++++++++++++++++++
 src/ip_resolver.cpp          |  4 ++--
 src/udp_address.cpp          |  3 +--
 5 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 74dd99ae..8b548302 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -546,11 +546,13 @@ if(ZMQ_HAVE_WINDOWS)
 
   set(CMAKE_REQUIRED_LIBRARIES "iphlpapi.lib")
   check_cxx_symbol_exists(GetAdaptersAddresses "winsock2.h;iphlpapi.h" HAVE_IPHLAPI)
+  check_cxx_symbol_exists(if_nametoindex "iphlpapi.h" HAVE_IF_NAMETOINDEX)
 
   set(CMAKE_REQUIRED_LIBRARIES "")
   # TODO: This not the symbol we're looking for. What is the symbol?
   check_library_exists(ws2 fopen "" HAVE_WS2)
 else()
+  check_cxx_symbol_exists(if_nametoindex net/if.h HAVE_IF_NAMETOINDEX)
   check_cxx_symbol_exists(SO_PEERCRED sys/socket.h ZMQ_HAVE_SO_PEERCRED)
   check_cxx_symbol_exists(LOCAL_PEERCRED sys/socket.h ZMQ_HAVE_LOCAL_PEERCRED)
 endif()
diff --git a/builds/cmake/platform.hpp.in b/builds/cmake/platform.hpp.in
index ff75ecfb..4b69606d 100644
--- a/builds/cmake/platform.hpp.in
+++ b/builds/cmake/platform.hpp.in
@@ -73,6 +73,7 @@
 #cmakedefine SODIUM_STATIC
 #cmakedefine ZMQ_USE_GNUTLS
 #cmakedefine ZMQ_USE_RADIX_TREE
+#cmakedefine HAVE_IF_NAMETOINDEX
 
 #ifdef _AIX
   #define ZMQ_HAVE_AIX
diff --git a/configure.ac b/configure.ac
index a7a1609a..c486615b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -788,6 +788,25 @@ AC_COMPILE_IFELSE(
 		AC_MSG_RESULT([no])
 ])
 
+AC_MSG_CHECKING([whether if_nametoindex is available])
+AC_COMPILE_IFELSE(
+    [AC_LANG_PROGRAM([[
+        #ifdef _WIN32
+        #include <iphlpapi.h>
+        #else
+        #include <sys/types.h>
+        #include <sys/socket.h>
+        #include <net/if.h>
+        #endif]], [[
+        if_nametoindex("");
+    ]])],[
+        AC_MSG_RESULT([yes])
+        AC_DEFINE(HAVE_IF_NAMETOINDEX, [1],
+        [if_nametoindex is available])
+    ],[
+        AC_MSG_RESULT([no])
+])
+
 AC_ARG_ENABLE([libbsd],
     [AS_HELP_STRING([--enable-libbsd],
         [enable libbsd [default=auto]])],
diff --git a/src/ip_resolver.cpp b/src/ip_resolver.cpp
index 535096d8..97d87b21 100644
--- a/src/ip_resolver.cpp
+++ b/src/ip_resolver.cpp
@@ -726,10 +726,10 @@ void zmq::ip_resolver_t::do_freeaddrinfo (struct addrinfo *res_)
     freeaddrinfo (res_);
 }
 
+
 unsigned int zmq::ip_resolver_t::do_if_nametoindex (const char *ifname_)
 {
-#if _WIN32_WINNT > _WIN32_WINNT_WINXP && !defined ZMQ_HAVE_WINDOWS_UWP         \
-  && !defined ZMQ_HAVE_VXWORKS
+#ifdef HAVE_IF_NAMETOINDEX
     return if_nametoindex (ifname_);
 #else
     LIBZMQ_UNUSED (ifname_);
diff --git a/src/udp_address.cpp b/src/udp_address.cpp
index 76d4bac4..41e4770d 100644
--- a/src/udp_address.cpp
+++ b/src/udp_address.cpp
@@ -104,8 +104,7 @@ int zmq::udp_address_t::resolve (const char *name_, bool bind_, bool ipv6_)
         if (src_name == "*") {
             _bind_interface = 0;
         } else {
-#if _WIN32_WINNT > _WIN32_WINNT_WINXP && !defined ZMQ_HAVE_WINDOWS_UWP         \
-  && !defined ZMQ_HAVE_VXWORKS
+#ifdef HAVE_IF_NAMETOINDEX
             _bind_interface = if_nametoindex (src_name.c_str ());
             if (_bind_interface == 0) {
                 //  Error, probably not an interface name.