From 2200b68aff24f146574c71200c73c4e48a6ab30b Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Fri, 4 Apr 2014 03:55:32 -0400
Subject: [PATCH] Print a warning if the BPF is not installed for an ARP
 socket.

---
 ndhc/arp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ndhc/arp.c b/ndhc/arp.c
index 50b0274..4bd1cca 100644
--- a/ndhc/arp.c
+++ b/ndhc/arp.c
@@ -151,6 +151,9 @@ static void arp_set_bpf_basic(int fd)
     };
     using_arp_bpf = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &sfp_arp,
                                sizeof sfp_arp) != -1;
+    if (!using_arp_bpf)
+        log_warning("%s: Failed to set BPF for ARP socket: %s",
+                    client_config.interface, strerror(errno));
 }
 
 static void arp_set_bpf_defense(struct client_state_t *cs, int fd)