add carppeer; an option to specify a different multicast address or

even the unicast address of the remote carp peer. this especially
helps when the multicast carp advertisements are causing problems in
the network (some crappy switches don't do well with multicast), there
are conflicts with VRRP, or the policy of the network does not allow
multicast (most Internet eXchange points didn't allow carped OpenBGP
routers because of the multicast advertisements).

discussed with many
ok mpf@

2 files changed, 59 insertions, 28 deletions

diff --git a/sys/netinet/ip_carp.c b/sys/netinet/ip_carp.c
index ca82bcf5c9f..67868b7d243 100644
--- a/sys/netinet/ip_carp.c
+++ b/sys/netinet/ip_carp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_carp.c,v 1.166 2008/06/13 23:29:31 mpf Exp $	*/
+/*	$OpenBSD: ip_carp.c,v 1.167 2008/06/14 21:46:22 reyk Exp $	*/
 
 /*
  * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
@@ -167,6 +167,8 @@ struct carp_softc {
 	int sc_lscount;			/* # load sharing interfaces (max 32) */
 	int sc_delayed_arp;		/* delayed ARP request countdown */
 
+	struct in_addr sc_peer;
+
 	LIST_HEAD(__carp_mchead, carp_mc_entry)	carp_mc_listhead;
 	struct carp_vhost_entry *cur_vhe; /* current active vhe */
 };
@@ -201,7 +203,8 @@ void	carp_hmac_generate(struct carp_vhost_entry *, u_int32_t *,
 int	carp_hmac_verify(struct carp_vhost_entry *, u_int32_t *,
 	    unsigned char *);
 void	carp_setroute(struct carp_softc *, int);
-void	carp_proto_input_c(struct mbuf *, struct carp_header *, sa_family_t);
+void	carp_proto_input_c(struct mbuf *, struct carp_header *, int,
+	    sa_family_t);
 void	carpattach(int);
 void	carpdetach(struct carp_softc *);
 int	carp_prepare_ad(struct mbuf *, struct carp_vhost_entry *,
@@ -527,9 +530,10 @@ void
 carp_proto_input(struct mbuf *m, ...)
 {
 	struct ip *ip = mtod(m, struct ip *);
+	struct ifnet *ifp = m->m_pkthdr.rcvif;
 	struct carp_softc *sc = NULL;
 	struct carp_header *ch;
-	int iplen, len, hlen;
+	int iplen, len, hlen, ismulti;
 	va_list ap;
 
 	va_start(ap, m);
@@ -543,8 +547,11 @@ carp_proto_input(struct mbuf *m, ...)
 		return;
 	}
 
+	ismulti = IN_MULTICAST(ip->ip_dst.s_addr);
+
 	/* check if received on a valid carp interface */
-	if (m->m_pkthdr.rcvif->if_type != IFT_CARP) {
+	if (!((ifp->if_type == IFT_CARP && ismulti) ||
+	    (ifp->if_type != IFT_CARP && !ismulti && ifp->if_carp != NULL))) {
 		carpstats.carps_badif++;
 		CARP_LOG(LOG_INFO, sc, ("packet received on non-carp interface: %s",
 		    m->m_pkthdr.rcvif->if_xname));
@@ -593,7 +600,7 @@ carp_proto_input(struct mbuf *m, ...)
 	}
 	m->m_data -= iplen;
 
-	carp_proto_input_c(m, ch, AF_INET);
+	carp_proto_input_c(m, ch, ismulti, AF_INET);
 }
 
 #ifdef INET6
@@ -652,20 +659,30 @@ carp6_proto_input(struct mbuf **mp, int *offp, int proto)
 	}
 	m->m_data -= *offp;
 
-	carp_proto_input_c(m, ch, AF_INET6);
+	carp_proto_input_c(m, ch, 1, AF_INET6);
 	return (IPPROTO_DONE);
 }
 #endif /* INET6 */
 
 void
-carp_proto_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
+carp_proto_input_c(struct mbuf *m, struct carp_header *ch, int ismulti,
+    sa_family_t af)
 {
+	struct ifnet *ifp = m->m_pkthdr.rcvif;
 	struct carp_softc *sc;
 	struct carp_vhost_entry *vhe;
 	struct timeval sc_tv, ch_tv;
+	struct carp_if *cif;
+
+	if (ifp->if_type == IFT_CARP)
+		cif = (struct carp_if *)ifp->if_carpdev->if_carp;
+	else
+		cif = (struct carp_if *)ifp->if_carp;
 
-	TAILQ_FOREACH(sc, &((struct carp_if *)
-	    m->m_pkthdr.rcvif->if_carpdev->if_carp)->vhif_vrs, sc_list) {
+	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
+		if (af == AF_INET &&
+		    ismulti != IN_MULTICAST(sc->sc_peer.s_addr))
+			continue;
 		LIST_FOREACH(vhe, &sc->carp_vhosts, vhost_entries) {
 			if (vhe->vhid == ch->carp_vhid)
 				goto found;
@@ -1119,7 +1136,6 @@ carp_send_ad(void *v)
 		m->m_pkthdr.rcvif = NULL;
 		m->m_len = len;
 		MH_ALIGN(m, m->m_len);
-		m->m_flags |= M_MCAST;
 		ip = mtod(m, struct ip *);
 		ip->ip_v = IPVERSION;
 		ip->ip_hl = sizeof(*ip) >> 2;
@@ -1139,7 +1155,9 @@ carp_send_ad(void *v)
 		else
 			ip->ip_src.s_addr =
 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
-		ip->ip_dst.s_addr = INADDR_CARP_GROUP;
+		ip->ip_dst.s_addr = sc->sc_peer.s_addr;
+		if (IN_MULTICAST(ip->ip_dst.s_addr))
+			m->m_flags |= M_MCAST;
 
 		ch_ptr = (void *)ip + sizeof(*ip);
 		bcopy(&ch, ch_ptr, sizeof(ch));
@@ -1466,7 +1484,7 @@ carp_iamatch6(struct ifnet *ifp, u_char *src, struct sockaddr_dl **sdl)
 #endif /* INET6 */
 
 struct ifnet *
-carp_ourether(void *v, struct ether_header *eh, u_char iftype, int src)
+carp_ourether(void *v, struct ether_header *eh, int src)
 {
 	struct carp_if *cif = (struct carp_if *)v;
 	struct carp_softc *vh;
@@ -1537,7 +1555,7 @@ carp_input(struct mbuf *m, u_int8_t *shost, u_int8_t *dhost, u_int16_t etype)
 	bcopy(dhost, &eh.ether_dhost, sizeof(eh.ether_dhost));
 	eh.ether_type = etype;
 
-	if ((ifp = carp_ourether(cif, &eh, m->m_pkthdr.rcvif->if_type, 0)))
+	if ((ifp = carp_ourether(cif, &eh, 0)))
 		;
 	else if (m->m_flags & (M_BCAST|M_MCAST)) {
 		struct carp_softc *vh;
@@ -1925,18 +1943,22 @@ carp_addr_updated(void *v)
 		sc->sc_naddrs6 = new_naddrs6;
 
 		/* Re-establish multicast membership removed by in_control */
-		mc_addr.s_addr = INADDR_CARP_GROUP;
-		IN_LOOKUP_MULTI(mc_addr, &sc->sc_if, inm);
-		if (inm == NULL) {
-			struct in_multi **imm = sc->sc_imo.imo_membership;
-			u_int16_t maxmem = sc->sc_imo.imo_max_memberships;
-
-			bzero(&sc->sc_imo, sizeof(sc->sc_imo));
-			sc->sc_imo.imo_membership = imm;
-			sc->sc_imo.imo_max_memberships = maxmem;
-
-			if (sc->sc_carpdev != NULL && sc->sc_naddrs > 0)
-				carp_join_multicast(sc);
+		if (IN_MULTICAST(sc->sc_peer.s_addr)) {
+			mc_addr.s_addr = sc->sc_peer.s_addr;
+			IN_LOOKUP_MULTI(mc_addr, &sc->sc_if, inm);
+			if (inm == NULL) {
+				struct in_multi **imm =
+				    sc->sc_imo.imo_membership;
+				u_int16_t maxmem =
+				    sc->sc_imo.imo_max_memberships;
+
+				bzero(&sc->sc_imo, sizeof(sc->sc_imo));
+				sc->sc_imo.imo_membership = imm;
+				sc->sc_imo.imo_max_memberships = maxmem;
+
+				if (sc->sc_carpdev != NULL && sc->sc_naddrs > 0)
+					carp_join_multicast(sc);
+			}
 		}
 
 		if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) {
@@ -2024,7 +2046,10 @@ carp_join_multicast(struct carp_softc *sc)
 	struct in_multi *imm;
 	struct in_addr addr;
 
-	addr.s_addr = INADDR_CARP_GROUP;
+	if (!IN_MULTICAST(sc->sc_peer.s_addr))
+		return (0);
+
+	addr.s_addr = sc->sc_peer.s_addr;
 	if ((imm = in_addmulti(&addr, &sc->sc_if)) == NULL)
 		return (ENOBUFS);
 
@@ -2222,6 +2247,10 @@ carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
 		if (carpr.carpr_carpdev[0] != '\0' &&
 		    (cdev = ifunit(carpr.carpr_carpdev)) == NULL)
 			return (EINVAL);
+		if (carpr.carpr_peer.s_addr == 0)
+			sc->sc_peer.s_addr = INADDR_CARP_GROUP;
+		else
+			sc->sc_peer.s_addr = carpr.carpr_peer.s_addr;
 		if ((error = carp_set_ifp(sc, cdev)))
 			return (error);
 		if (vhe->state != INIT && carpr.carpr_state != vhe->state) {
@@ -2294,6 +2323,7 @@ carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
 		if (suser(p, p->p_acflag) == 0)
 			bcopy(sc->sc_key, carpr.carpr_key,
 			    sizeof(carpr.carpr_key));
+		carpr.carpr_peer.s_addr = sc->sc_peer.s_addr;
 		error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
 		break;
 
diff --git a/sys/netinet/ip_carp.h b/sys/netinet/ip_carp.h
index 857d8563c2b..145bc9d4023 100644
--- a/sys/netinet/ip_carp.h
+++ b/sys/netinet/ip_carp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_carp.h,v 1.26 2008/02/05 22:57:31 mpf Exp $	*/
+/*	$OpenBSD: ip_carp.h,v 1.27 2008/06/14 21:46:22 reyk Exp $	*/
 
 /*
  * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
@@ -142,6 +142,7 @@ struct carpreq {
 	u_int8_t	carpr_balancing;
 	int		carpr_advbase;
 	unsigned char	carpr_key[CARP_KEY_LEN];
+	struct in_addr	carpr_peer;
 };
 
 /*
@@ -170,7 +171,7 @@ int		 carp6_proto_input(struct mbuf **, int *, int);
 int		 carp_iamatch(struct in_ifaddr *, u_char *, u_int8_t **,
 		     u_int8_t **);
 int		 carp_iamatch6(struct ifnet *, u_char *, struct sockaddr_dl **);
-struct ifnet	*carp_ourether(void *, struct ether_header *, u_char, int);
+struct ifnet	*carp_ourether(void *, struct ether_header *, int);
 int		 carp_input(struct mbuf *, u_int8_t *, u_int8_t *, u_int16_t);
 int		 carp_output(struct ifnet *, struct mbuf *, struct sockaddr *,
 		     struct rtentry *);