From 3db149b42e5b0aadccb7f35519cde2c96bf2314b Mon Sep 17 00:00:00 2001
From: Henrik Persson <henrik.persson@securitas-direct.com>
Date: Wed, 5 Sep 2012 14:16:45 +0200
Subject: [PATCH] Fix corner case with dhcp timeouts

If t1 >= t2 timeout then only t2 timer should be scheduled. This can happen
when a sub 1 minute lease is received.
---
 src/core/dhcp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/core/dhcp.c b/src/core/dhcp.c
index 41acbfff..071190d6 100644
--- a/src/core/dhcp.c
+++ b/src/core/dhcp.c
@@ -962,6 +962,11 @@ dhcp_bind(struct netif *netif)
     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
   }
 
+  /* If we have sub 1 minute lease, t2 and t1 will kick in at the same time. */
+  if (dhcp->t1_timeout >= dhcp->t2_timeout && dhcp->t2_timeout > 0) {
+    dhcp->t1_timeout = 0;
+  }
+
   if (dhcp->subnet_mask_given) {
     /* copy offered network mask */
     ip_addr_copy(sn_mask, dhcp->offered_sn_mask);