From 893ddcf61b06a8104e6122b2eb270a9654c251c4 Mon Sep 17 00:00:00 2001
From: stoklund <stoklund>
Date: Thu, 23 Jul 2009 08:59:13 +0000
Subject: [PATCH] Implement exponential backoff in dhcp.c

---
 src/core/dhcp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/core/dhcp.c b/src/core/dhcp.c
index f5b7a9da..df0f9788 100644
--- a/src/core/dhcp.c
+++ b/src/core/dhcp.c
@@ -298,7 +298,7 @@ dhcp_select(struct netif *netif)
     LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_select: could not allocate DHCP request\n"));
   }
   dhcp->tries++;
-  msecs = dhcp->tries < 4 ? dhcp->tries * 1000 : 4 * 1000;
+  msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_select(): set request timeout %"U16_F" msecs\n", msecs));
   return result;
@@ -828,7 +828,7 @@ dhcp_discover(struct netif *netif)
     autoip_start(netif);
   }
 #endif /* LWIP_DHCP_AUTOIP_COOP */
-  msecs = dhcp->tries < 4 ? (dhcp->tries + 1) * 1000 : 10 * 1000;
+  msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
   dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
   LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
   return result;