From 183b6468bf928353909883718108ad7581c483e9 Mon Sep 17 00:00:00 2001
From: Fabian Keil <fk@fabiankeil.de>
Date: Fri, 11 Sep 2020 12:30:10 +0200
Subject: [PATCH] Add connection_detail_matches() as helper function for
 connection_destination_matches()

Unlike the code it replaces it properly detects a mismatch
if only one detail is set.
---
 gateway.c | 52 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/gateway.c b/gateway.c
index 4207cb7c..f1de5380 100644
--- a/gateway.c
+++ b/gateway.c
@@ -336,6 +336,42 @@ void forget_connection(jb_socket sfd)
 
 
 #ifdef FEATURE_CONNECTION_KEEP_ALIVE
+/*********************************************************************
+ *
+ * Function    :  connection_detail_matches
+ *
+ * Description :  Helper function for connection_destination_matches().
+ *                Compares strings which can be NULL.
+ *
+ * Parameters  :
+ *          1  :  connection_detail = The connection detail to compare.
+ *          2  :  fowarder_detail = The forwarder detail to compare.
+ *
+ * Returns     :  TRUE for yes, FALSE otherwise.
+ *
+ *********************************************************************/
+static int connection_detail_matches(const char *connection_detail,
+                                     const char *forwarder_detail)
+{
+   if (connection_detail == NULL && forwarder_detail == NULL)
+   {
+      /* Both details are unset. */
+      return TRUE;
+   }
+
+   if ((connection_detail == NULL && forwarder_detail != NULL)
+    || (connection_detail != NULL && forwarder_detail == NULL))
+   {
+      /* Only one detail isn't set. */
+      return FALSE;
+   }
+
+   /* Both details are set, but do they match? */
+   return(!strcmpic(connection_detail, forwarder_detail));
+
+}
+
+
 /*********************************************************************
  *
  * Function    :  connection_destination_matches
@@ -364,25 +400,21 @@ int connection_destination_matches(const struct reusable_connection *connection,
       return FALSE;
    }
 
-   if ((    (NULL != connection->gateway_host)
-         && (NULL != fwd->gateway_host)
-         && strcmpic(connection->gateway_host, fwd->gateway_host))
-       && (connection->gateway_host != fwd->gateway_host))
+   if (!connection_detail_matches(connection->gateway_host, fwd->gateway_host))
    {
       log_error(LOG_LEVEL_CONNECT,
          "Gateway mismatch. Previous gateway: %s. Current gateway: %s",
-         connection->gateway_host, fwd->gateway_host);
+         connection->gateway_host != NULL ? connection->gateway_host : "none",
+         fwd->gateway_host != NULL ? fwd->gateway_host : "none");
       return FALSE;
    }
 
-   if ((    (NULL != connection->forward_host)
-         && (NULL != fwd->forward_host)
-         && strcmpic(connection->forward_host, fwd->forward_host))
-      && (connection->forward_host != fwd->forward_host))
+   if (!connection_detail_matches(connection->forward_host, fwd->forward_host))
    {
       log_error(LOG_LEVEL_CONNECT,
          "Forwarding proxy mismatch. Previous proxy: %s. Current proxy: %s",
-         connection->forward_host, fwd->forward_host);
+         connection->forward_host != NULL ? connection->forward_host : "none",
+         fwd->forward_host != NULL ? fwd->forward_host : "none");
       return FALSE;
    }
 
-- 
2.39.2