Subject: Check for remote IP duplicates in pptpd.conf
Origin: upstream, 1.4.0-16-g0c0ad67
Upstream-Author: Christoph Biedl <sourceforge.bnwi@manchmal.in-ulm.de>
Date: Fri Jul 8 13:51:42 2016 +1000

    At the moment, pptpd will happily process lines like
    
    	remoteip 192.168.0.234-234,192.168.0.234,192.168.0.234
    
    and afterwards state "MGR: Maximum of 3 connections available". While
    technically true, I guess this is never by intention but will result in
    interesting behaviour.  [...]
    
    The patch below worked for me.
    
    Signed-off-by: James Cameron <quozl@laptop.org>

--- a/pptpmanager.c
+++ b/pptpmanager.c
@@ -136,6 +136,13 @@
 void slot_set_remote(int i, char *ip)
 {
   struct slot *slot = &slots[i];
+  int j;
+  for (j = 0; j < slot_count; j++) {
+    if (!slots[j].remote || strcmp(slots[j].remote, ip))
+      continue;
+    syslog(LOG_ERR, "MGR: Remote IP address %s in config is a duplicate!", ip);
+    exit(1);
+  }
   if (slot->remote) free(slot->remote);
   slot->remote = strdup(ip);
 }