When a DHCP server sends an invalid T1 or T2 default back to the default

values as specified in RFC2131 section 4.4.5. Allows my Comtrend VI-3223u
to work.

OK florian@

diff --git a/sbin/dhcpleased/engine.c b/sbin/dhcpleased/engine.c
index a98dc3d..e301c20 100644 (file)
--- a/sbin/dhcpleased/engine.c
+++ b/sbin/dhcpleased/engine.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: engine.c,v 1.11 2021/03/22 15:34:07 otto Exp $        */
+/*     $OpenBSD: engine.c,v 1.12 2021/04/09 14:46:39 martijn Exp $     */
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -972,23 +972,24 @@ parse_dhcp(struct dhcpleased_iface *iface, struct imsg_dhcp *dhcp)
                }
 
                /* RFC 2131 4.4.5 */
+               /* Ignore invalid T1/T2 options */
+               if (renewal_time >= rebinding_time) {
+                       log_warnx("%s: renewal_time(%u) >= rebinding_time(%u) "
+                           "from %s: using defaults",
+                           __func__, renewal_time, rebinding_time, from);
+                       renewal_time = rebinding_time = 0;
+               } else if (rebinding_time >= lease_time) {
+                       log_warnx("%s: rebinding_time(%u) >= lease_time(%u) "
+                           "from %s: using defaults",
+                           __func__, rebinding_time, lease_time, from);
+                       renewal_time = rebinding_time = 0;
+               }
+
                if(renewal_time == 0)
                        renewal_time = lease_time / 2;
                if (rebinding_time == 0)
                        rebinding_time = lease_time - (lease_time / 8);
 
-               if (renewal_time >= rebinding_time) {
-                       log_warnx("%s: renewal_time >= rebinding_time "
-                           "(%u >= %u) from %s", __func__, renewal_time,
-                           rebinding_time, from);
-                       return;
-               }
-               if (rebinding_time >= lease_time) {
-                       log_warnx("%s: rebinding_time >= lease_time"
-                           "(%u >= %u) from %s", __func__, rebinding_time,
-                           lease_time, from);
-                       return;
-               }
                clock_gettime(CLOCK_MONOTONIC, &iface->request_time);
                iface->server_identifier.s_addr = server_identifier.s_addr;
                iface->requested_ip.s_addr = dhcp_hdr->yiaddr.s_addr;