Add CARP (Common Address Redundancy Protocol), which allows multiple

hosts to share an IP address, providing high availability and load
balancing.

Original work on CARP done by Michael Shalayeff, with many
additions by Marco Pfatschbacher and Ryan McBride.

FreeBSD port done solely by Max Laier.

Patch by:	mlaier
Obtained from:	OpenBSD (mickey, mcbride)

1 files changed, 11 insertions, 0 deletions

diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 3021285..ecf79ae 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -35,6 +35,7 @@
 #include "opt_ipstealth.h"
 #include "opt_ipsec.h"
 #include "opt_mac.h"
+#include "opt_carp.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -66,6 +67,9 @@
 #include <netinet/ip_var.h>
 #include <netinet/ip_icmp.h>
 #include <machine/in_cksum.h>
+#ifdef DEV_CARP
+#include <netinet/ip_carp.h>
+#endif
 
 #include <sys/socketvar.h>
 
@@ -509,10 +513,17 @@ passin:
 	 * XXX - Checking is incompatible with IP aliases added
 	 * to the loopback interface instead of the interface where
 	 * the packets are received.
+	 *
+	 * XXX - This is the case for carp vhost IPs as well so we
+	 * insert a workaround. If the packet got here, we already
+	 * checked with carp_iamatch() and carp_forus().
 	 */
 	checkif = ip_checkinterface && (ipforwarding == 0) && 
 	    m->m_pkthdr.rcvif != NULL &&
 	    ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
+#ifdef DEV_CARP
+	    !m->m_pkthdr.rcvif->if_carp &&
+#endif
 	    (dchg == 0);
 
 	/*