From db5ed32b0eb8374ccfd9660d089bd17bb57a9709 Mon Sep 17 00:00:00 2001
Message-Id: <db5ed32b0eb8374ccfd9660d089bd17bb57a9709.1283957680.git.jdenemar@redhat.com>
From: Stefan Berger <stefanb@us.ibm.com>
Date: Fri, 13 Aug 2010 16:41:39 -0400
Subject: [PATCH] nwfilter: Discard class D,E IP addresses when sniffing pkts

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=630574

When sniffing the network traffic, discard class D and E IP addresses
when sniffing traffic. This was a reason why filters were not correctly
rebuilt on VMs on the local 192.* network when libvirt was restarted and
those VMs did not use a DHCP request to get its IP address.
(cherry picked from commit 753d76e0cd3554acb6c087d1ce3a2aa6f1dda203)
---
 src/nwfilter/nwfilter_learnipaddr.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c
index 71dc240..b4536a8 100644
--- a/src/nwfilter/nwfilter_learnipaddr.c
+++ b/src/nwfilter/nwfilter_learnipaddr.c
@@ -546,9 +546,11 @@ learnIPAddressThread(void *arg)
                     struct iphdr *iphdr = (struct iphdr*)(packet +
                                                           ethHdrSize);
                     vmaddr = iphdr->saddr;
-                    // skip eth. bcast and mcast addresses,
-                    // and zero address in DHCP Requests
-                    if ((ntohl(vmaddr) & 0xc0000000) || vmaddr == 0) {
+                    // skip mcast addresses (224.0.0.0 - 239.255.255.255),
+                    // class E (240.0.0.0 - 255.255.255.255, includes eth.
+                    // bcast) and zero address in DHCP Requests
+                    if ( (ntohl(vmaddr) & 0xe0000000) == 0xe0000000 ||
+                         vmaddr == 0) {
                         vmaddr = 0;
                         continue;
                     }
-- 
1.7.2.2