From 31ef04179f144d972f66306374aaa439b661e118 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

---
 include/tools.h               |  9 +++++++++
 src/server/internalServer.cpp |  5 +++++
 src/tools/networkTools.cpp    | 12 ++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/include/tools.h b/include/tools.h
index f68fe9cdf..5c6c2a58a 100644
--- a/include/tools.h
+++ b/include/tools.h
@@ -225,6 +225,15 @@ IpAddress getBestPublicIps(IpMode mode);
  */
 std::string getBestPublicIp();
 
+/** Checks if IP address is available
+ *
+ * Check if the given IP address is configured on any network interface of the system
+ *
+ * @param addr the IP address to check.
+ * @return true if the IP address is available on the system.
+ */
+bool ipAvailable(const IpAddress& addr);
+
 /** Converts file size to human readable format.
  *
  * This function will convert a number to its equivalent size using units.
diff --git a/src/server/internalServer.cpp b/src/server/internalServer.cpp
index de20f73cc..800275bb8 100644
--- a/src/server/internalServer.cpp
+++ b/src/server/internalServer.cpp
@@ -474,6 +474,11 @@ bool InternalServer::start() {
       std::cerr << "IP address " << addr << " is not valid" << std::endl;
       return false;
     }
+
+    if (!ipAvailable(m_addr)) {
+      std::cerr << "IP address " << (m_addr.addr.empty() ? m_addr.addr6 : m_addr.addr) << " is not available on this system" << std::endl;
+      return false;
+    }
   }
 
   if (m_ipMode == IpMode::ALL) {
diff --git a/src/tools/networkTools.cpp b/src/tools/networkTools.cpp
index 152802b5d..e55afde16 100644
--- a/src/tools/networkTools.cpp
+++ b/src/tools/networkTools.cpp
@@ -246,4 +246,16 @@ std::string getBestPublicIp()
   return getBestPublicIps(IpMode::ipv4).addr;
 }
 
+bool ipAvailable(const IpAddress& addr) 
+{
+  auto interfaces = kiwix::getNetworkInterfacesIPv4Or6();
+  for (const auto& interface : interfaces) {
+    IpAddress interfaceIps = interface.second;
+    if (!interfaceIps.addr.empty() && interfaceIps.addr == addr.addr) return true;
+    if (!interfaceIps.addr6.empty() && interfaceIps.addr6 == addr.addr6) return true;
+  }
+
+  return false;
+}
+
 } // namespace kiwix