From 52fbeb46ad4c84c93a0630a83a14340e2a9d56a6 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Tue, 28 Jun 2011 23:50:36 -0400
Subject: [PATCH] Fix a problem where, when ndhc is waiting for an arp packet,
 an arp packet is received that is discarded by ndhc's basic checks and
 provokes a busy loop in the main program loop because epoll_wait() constantly
 sees data that is never drained from the socket buffer since arp_offset
 exceeds the maximum size of an ARP packet and would overflow the packet
 buffer.

---
 ndhc/arp.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/ndhc/arp.c b/ndhc/arp.c
index 69d9f64..ce7086e 100644
--- a/ndhc/arp.c
+++ b/ndhc/arp.c
@@ -302,14 +302,15 @@ void handle_arp_response(struct client_state_t *cs)
             arpreply_offset += r;
     }
 
-    if (arpreply_offset < ARP_MSG_SIZE) {
-        log_warning("arp: Received short ARP message -- ignoring");
+
+    if (arpreply_offset < ARP_MSG_SIZE)
+        return;
+
+    if (!arp_validate(&arpreply)) {
+        arpreply_clear();
         return;
     }
 
-    if (!arp_validate(&arpreply))
-        return;
-
     ++arp_packet_num;
     switch (cs->dhcpState) {
     case DS_ARP_CHECK: