1 files changed, 29 insertions, 2 deletions

diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
index c99c465..4631be5 100644
--- a/sys/netinet/if_ether.c
+++ b/sys/netinet/if_ether.c
@@ -80,6 +80,8 @@ SYSCTL_DECL(_net_link_ether);
 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, "");
 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, "");
 
+static VNET_DEFINE(int, arp_carp_mac) = 0;	/* default to disabled */
+
 /* timer values */
 static VNET_DEFINE(int, arpt_keep) = (20*60);	/* once resolved, good for 20
 						 * minutes */
@@ -98,12 +100,16 @@ VNET_PCPUSTAT_SYSUNINIT(arpstat);
 
 static VNET_DEFINE(int, arp_maxhold) = 1;
 
+#define	V_arp_carp_mac		VNET(arp_carp_mac)
 #define	V_arpt_keep		VNET(arpt_keep)
 #define	V_arpt_down		VNET(arpt_down)
 #define	V_arp_maxtries		VNET(arp_maxtries)
 #define	V_arp_proxyall		VNET(arp_proxyall)
 #define	V_arp_maxhold		VNET(arp_maxhold)
 
+SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, carp_mac, CTLFLAG_RW,
+	&VNET_NAME(arp_carp_mac), 0,
+	"Send CARP mac with replies to CARP ips");
 SYSCTL_VNET_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW,
 	&VNET_NAME(arpt_keep), 0,
 	"ARP entry lifetime in seconds");
@@ -931,6 +937,29 @@ reply:
 		/* default behaviour; never reply by broadcast. */
 		m->m_flags &= ~(M_BCAST|M_MCAST);
 	}
+#ifdef DEV_CARP
+	if (V_arp_carp_mac && carp_match) {
+		struct ether_header *eh = (struct ether_header *) sa.sa_data;
+		short type = htons(ETHERTYPE_ARP);
+
+		ah->ar_hrd = htons(ARPHRD_ETHER);
+
+		(void)memcpy(&eh->ether_type, &type,
+			sizeof(eh->ether_type));
+		(void)memcpy(eh->ether_dhost, ar_tha(ah),
+			sizeof (eh->ether_dhost));
+		(void)memcpy(eh->ether_shost, enaddr,
+			sizeof(eh->ether_shost));
+
+		sa.sa_family = pseudo_AF_HDRCMPLT;
+		sa.sa_len = sizeof(sa);
+	} else {
+#endif
+		sa.sa_family = AF_ARP;
+		sa.sa_len = 2;
+#ifdef DEV_CARP
+	}
+#endif
 	(void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln);
 	(void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln);
 	ah->ar_op = htons(ARPOP_REPLY);
@@ -938,8 +967,6 @@ reply:
 	m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln);
 	m->m_pkthdr.len = m->m_len;
 	m->m_pkthdr.rcvif = NULL;
-	sa.sa_family = AF_ARP;
-	sa.sa_len = 2;
 	m_clrprotoflags(m);	/* Avoid confusing lower layers. */
 	(*ifp->if_output)(ifp, m, &sa, NULL);
 	ARPSTAT_INC(txreplies);