Start up icmp protocol; handle ICMP EchoReplies and also handle non-replies.

diff --git a/server/dhcpd.c b/server/dhcpd.c
index b99b44e4c2ab4e571fb6dde3c3d94cc6f94ebe52..36c7d23b4557973d4e7779e59721bb9c2d1f75e9 100644 (file)
--- a/server/dhcpd.c
+++ b/server/dhcpd.c
@@ -42,7 +42,7 @@
 
 #ifndef lint
 static char ocopyright[] =
-"$Id: dhcpd.c,v 1.39 1997/03/06 07:02:54 mellon Exp $ Copyright 1995, 1996 The Internet Software Consortium.";
+"$Id: dhcpd.c,v 1.40 1997/03/06 18:41:36 mellon Exp $ Copyright 1995, 1996 The Internet Software Consortium.";
 #endif
 
 static char copyright[] =
@@ -215,6 +215,9 @@ int main (argc, argv, envp)
        /* Discover all the network interfaces and initialize them. */
        discover_interfaces (1);
 
+       /* Initialize icmp support... */
+       icmp_startup (1, lease_pinged);
+
 #ifndef DEBUG
        /* If we were requested to log to stdout on the command line,
           keep doing so; otherwise, stop. */
@@ -268,3 +271,49 @@ static void usage ()
 void cleanup ()
 {
 }
+
+void lease_pinged (from, packet, length)
+       struct iaddr from;
+       u_int8_t *packet;
+       int length;
+{
+       struct lease *lp;
+
+       /* Don't try to look up a pinged lease if we aren't trying to
+          ping one - otherwise somebody could easily make us churn by
+          just forging repeated ICMP EchoReply packets for us to look
+          up. */
+       if (!outstanding_pings)
+               return;
+
+       lp = find_lease_by_ip_addr (from);
+
+       if (!lp) {
+               note ("unexpected ICMP Echo Reply from %s", piaddr (from));
+               return;
+       }
+
+       if (!lp -> state) {
+               warn ("ICMP Echo Reply for %s arrived late or is spurious.\n",
+                     piaddr (from));
+               return;
+       }
+
+       /* At this point it looks like we pinged a lease and got a
+          response, which shouldn't have happened. */
+       free_lease_state (lp -> state, "lease_pinged");
+       lp -> state = (struct lease_state *)0;
+
+       abandon_lease (lp, "pinged before offer");
+       cancel_timeout (lease_ping_timeout, lp);
+       --outstanding_pings;
+}
+
+void lease_ping_timeout (vlp)
+       void *vlp;
+{
+       struct lease *lp = vlp;
+
+       --outstanding_pings;
+       dhcp_reply (lp);
+}