From d71a005ce9183d67e45a9e6012042faa7f006e64 Mon Sep 17 00:00:00 2001
From: sgourdas <jim31700@gmail.com>
Date: Mon, 23 Sep 2024 19:18:57 +0300
Subject: [PATCH] Add ip availability check in server start

---
 src/server/internalServer.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/server/internalServer.cpp b/src/server/internalServer.cpp
index e51d2ed4d..2ecdb7ff7 100644
--- a/src/server/internalServer.cpp
+++ b/src/server/internalServer.cpp
@@ -85,6 +85,16 @@ namespace kiwix {
 namespace
 {
 
+bool ipAvailable(const std::string addr)
+{
+  auto interfaces = kiwix::getNetworkInterfacesIPv4Or6();
+
+  for (const auto& [_, interfaceIps] : interfaces)
+    if ((interfaceIps.addr == addr) || (interfaceIps.addr6 == addr)) return true;
+
+  return false;
+}
+
 inline std::string normalizeRootUrl(std::string rootUrl)
 {
   while ( !rootUrl.empty() && rootUrl.back() == '/' )
@@ -483,6 +493,10 @@ bool InternalServer::start() {
       std::cerr << "IP address " << addr << " is not a valid ip address." << std::endl;
       return false;
     } 
+    if (!ipAvailable(addr)) {
+      std::cerr << "IP address " << addr << " is not available on this system." << std::endl;
+      return false;
+    }
 
     m_ipMode = !m_addr.addr.empty() ? IpMode::IPV4 : IpMode::IPV6; 
   }