Merge pull request #8153 from reubendowle/nhrp-multicast

nhrp, ospf: add nhrp multicast for OSPF DMVPN

9 files changed, 451 insertions, 28 deletions

diff --git a/nhrpd/linux.c b/nhrpd/linux.c
index 9cabdbf06..bcf97f030 100644
--- a/nhrpd/linux.c
+++ b/nhrpd/linux.c
@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <string.h>
+#include <errno.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/types.h>
@@ -31,6 +32,11 @@
 #include "os.h"
 #include "netlink.h"
 
+#ifndef HAVE_STRLCPY
+size_t strlcpy(char *__restrict dest,
+	       const char *__restrict src, size_t destsize);
+#endif
+
 static int nhrp_socket_fd = -1;
 
 int os_socket(void)
@@ -42,7 +48,7 @@ int os_socket(void)
 }
 
 int os_sendmsg(const uint8_t *buf, size_t len, int ifindex, const uint8_t *addr,
-	       size_t addrlen)
+	       size_t addrlen, uint16_t protocol)
 {
 	struct sockaddr_ll lladdr;
 	struct iovec iov = {
@@ -61,16 +67,16 @@ int os_sendmsg(const uint8_t *buf, size_t len, int ifindex, const uint8_t *addr,
 
 	memset(&lladdr, 0, sizeof(lladdr));
 	lladdr.sll_family = AF_PACKET;
-	lladdr.sll_protocol = htons(ETH_P_NHRP);
+	lladdr.sll_protocol = htons(protocol);
 	lladdr.sll_ifindex = ifindex;
 	lladdr.sll_halen = addrlen;
 	memcpy(lladdr.sll_addr, addr, addrlen);
 
-	status = sendmsg(nhrp_socket_fd, &msg, 0);
+	status = sendmsg(os_socket(), &msg, 0);
 	if (status < 0)
-		return -1;
+		return -errno;
 
-	return 0;
+	return status;
 }
 
 int os_recvmsg(uint8_t *buf, size_t *len, int *ifindex, uint8_t *addr,
@@ -111,7 +117,7 @@ static int linux_configure_arp(const char *iface, int on)
 {
 	struct ifreq ifr;
 
-	strncpy(ifr.ifr_name, iface, IFNAMSIZ - 1);
+	strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
 	if (ioctl(nhrp_socket_fd, SIOCGIFFLAGS, &ifr))
 		return -1;
 
diff --git a/nhrpd/netlink.h b/nhrpd/netlink.h
index 74cb81daa..5e971cabf 100644
--- a/nhrpd/netlink.h
+++ b/nhrpd/netlink.h
@@ -13,6 +13,7 @@ union sockunion;
 struct interface;
 
 extern int netlink_nflog_group;
+extern int netlink_mcast_nflog_group;
 extern int netlink_req_fd;
 
 void netlink_init(void);
diff --git a/nhrpd/nhrp_interface.c b/nhrpd/nhrp_interface.c
index f6d89b141..402ffe9a2 100644
--- a/nhrpd/nhrp_interface.c
+++ b/nhrpd/nhrp_interface.c
@@ -42,6 +42,7 @@ static int nhrp_if_new_hook(struct interface *ifp)
 		struct nhrp_afi_data *ad = &nifp->afi[afi];
 		ad->holdtime = NHRPD_DEFAULT_HOLDTIME;
 		list_init(&ad->nhslist_head);
+		list_init(&ad->mcastlist_head);
 	}
 
 	return 0;
@@ -55,6 +56,7 @@ static int nhrp_if_delete_hook(struct interface *ifp)
 
 	nhrp_cache_interface_del(ifp);
 	nhrp_nhs_interface_del(ifp);
+	nhrp_multicast_interface_del(ifp);
 	nhrp_peer_interface_del(ifp);
 
 	if (nifp->ipsec_profile)
diff --git a/nhrpd/nhrp_multicast.c b/nhrpd/nhrp_multicast.c
new file mode 100644
index 000000000..b78afda2c
--- /dev/null
+++ b/nhrpd/nhrp_multicast.c
@@ -0,0 +1,305 @@
+/* NHRP Multicast Support
+ * Copyright (c) 2020-2021 4RF Limited
+ *
+ * This file is free software: you may copy, redistribute and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <fcntl.h>
+#include <net/if.h>
+#include <net/ethernet.h>
+#include <netinet/if_ether.h>
+#include <linux/netlink.h>
+#include <linux/neighbour.h>
+#include <linux/netfilter/nfnetlink_log.h>
+#include <linux/if_packet.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "thread.h"
+#include "nhrpd.h"
+#include "netlink.h"
+#include "znl.h"
+#include "os.h"
+
+DEFINE_MTYPE_STATIC(NHRPD, NHRP_MULTICAST, "NHRP Multicast");
+
+int netlink_mcast_nflog_group;
+static int netlink_mcast_log_fd = -1;
+static struct thread *netlink_mcast_log_thread;
+
+struct mcast_ctx {
+	struct interface *ifp;
+	struct zbuf *pkt;
+};
+
+static void nhrp_multicast_send(struct nhrp_peer *p, struct zbuf *zb)
+{
+	size_t addrlen;
+	int ret;
+
+	addrlen = sockunion_get_addrlen(&p->vc->remote.nbma);
+	ret = os_sendmsg(zb->head, zbuf_used(zb), p->ifp->ifindex,
+			 sockunion_get_addr(&p->vc->remote.nbma), addrlen,
+			 addrlen == 4 ? ETH_P_IP : ETH_P_IPV6);
+
+	debugf(NHRP_DEBUG_COMMON,
+	       "Multicast Packet: %pSU -> %pSU, ret = %d, size = %zu, addrlen = %zu",
+	       &p->vc->local.nbma, &p->vc->remote.nbma, ret, zbuf_used(zb),
+	       addrlen);
+}
+
+static void nhrp_multicast_forward_nbma(union sockunion *nbma_addr,
+					struct interface *ifp, struct zbuf *pkt)
+{
+	struct nhrp_peer *p = nhrp_peer_get(ifp, nbma_addr);
+
+	if (p && p->online) {
+		/* Send packet */
+		nhrp_multicast_send(p, pkt);
+	}
+	nhrp_peer_unref(p);
+}
+
+static void nhrp_multicast_forward_cache(struct nhrp_cache *c, void *pctx)
+{
+	struct mcast_ctx *ctx = (struct mcast_ctx *)pctx;
+
+	if (c->cur.type == NHRP_CACHE_DYNAMIC && c->cur.peer)
+		nhrp_multicast_forward_nbma(&c->cur.peer->vc->remote.nbma,
+					    ctx->ifp, ctx->pkt);
+}
+
+static void nhrp_multicast_forward(struct nhrp_multicast *mcast, void *pctx)
+{
+	struct mcast_ctx *ctx = (struct mcast_ctx *)pctx;
+	struct nhrp_interface *nifp = ctx->ifp->info;
+
+	if (!nifp->enabled)
+		return;
+
+	/* dynamic */
+	if (sockunion_family(&mcast->nbma_addr) == AF_UNSPEC) {
+		nhrp_cache_foreach(ctx->ifp, nhrp_multicast_forward_cache,
+				   pctx);
+		return;
+	}
+
+	/* Fixed IP Address */
+	nhrp_multicast_forward_nbma(&mcast->nbma_addr, ctx->ifp, ctx->pkt);
+}
+
+static void netlink_mcast_log_handler(struct nlmsghdr *msg, struct zbuf *zb)
+{
+	struct nfgenmsg *nf;
+	struct rtattr *rta;
+	struct zbuf rtapl;
+	uint32_t *out_ndx = NULL;
+	afi_t afi;
+	struct mcast_ctx ctx;
+
+	nf = znl_pull(zb, sizeof(*nf));
+	if (!nf)
+		return;
+
+	ctx.pkt = NULL;
+	while ((rta = znl_rta_pull(zb, &rtapl)) != NULL) {
+		switch (rta->rta_type) {
+		case NFULA_IFINDEX_OUTDEV:
+			out_ndx = znl_pull(&rtapl, sizeof(*out_ndx));
+			break;
+		case NFULA_PAYLOAD:
+			ctx.pkt = &rtapl;
+			break;
+			/* NFULA_HWHDR exists and is supposed to contain source
+			 * hardware address. However, for ip_gre it seems to be
+			 * the nexthop destination address if the packet matches
+			 * route.
+			 */
+		}
+	}
+
+	if (!out_ndx || !ctx.pkt)
+		return;
+
+	ctx.ifp = if_lookup_by_index(htonl(*out_ndx), VRF_DEFAULT);
+	if (!ctx.ifp)
+		return;
+
+	debugf(NHRP_DEBUG_COMMON,
+	       "Intercepted multicast packet leaving %s len %zu",
+	       ctx.ifp->name, zbuf_used(ctx.pkt));
+
+	for (afi = 0; afi < AFI_MAX; afi++) {
+		nhrp_multicast_foreach(ctx.ifp, afi, nhrp_multicast_forward,
+				       (void *)&ctx);
+	}
+}
+
+static int netlink_mcast_log_recv(struct thread *t)
+{
+	uint8_t buf[65535]; /* Max OSPF Packet size */
+	int fd = THREAD_FD(t);
+	struct zbuf payload, zb;
+	struct nlmsghdr *n;
+
+	netlink_mcast_log_thread = NULL;
+
+	zbuf_init(&zb, buf, sizeof(buf), 0);
+	while (zbuf_recv(&zb, fd) > 0) {
+		while ((n = znl_nlmsg_pull(&zb, &payload)) != NULL) {
+			debugf(NHRP_DEBUG_COMMON,
+			       "Netlink-mcast-log: Received msg_type %u, msg_flags %u",
+			       n->nlmsg_type, n->nlmsg_flags);
+			switch (n->nlmsg_type) {
+			case (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_PACKET:
+				netlink_mcast_log_handler(n, &payload);
+				break;
+			}
+		}
+	}
+
+	thread_add_read(master, netlink_mcast_log_recv, 0, netlink_mcast_log_fd,
+			&netlink_mcast_log_thread);
+
+	return 0;
+}
+
+static void netlink_mcast_log_register(int fd, int group)
+{
+	struct nlmsghdr *n;
+	struct nfgenmsg *nf;
+	struct nfulnl_msg_config_cmd cmd;
+	struct zbuf *zb = zbuf_alloc(512);
+
+	n = znl_nlmsg_push(zb, (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG,
+			   NLM_F_REQUEST | NLM_F_ACK);
+	nf = znl_push(zb, sizeof(*nf));
+	*nf = (struct nfgenmsg){
+		.nfgen_family = AF_UNSPEC,
+		.version = NFNETLINK_V0,
+		.res_id = htons(group),
+	};
+	cmd.command = NFULNL_CFG_CMD_BIND;
+	znl_rta_push(zb, NFULA_CFG_CMD, &cmd, sizeof(cmd));
+	znl_nlmsg_complete(zb, n);
+
+	zbuf_send(zb, fd);
+	zbuf_free(zb);
+}
+
+void netlink_mcast_set_nflog_group(int nlgroup)
+{
+	if (netlink_mcast_log_fd >= 0) {
+		THREAD_OFF(netlink_mcast_log_thread);
+		close(netlink_mcast_log_fd);
+		netlink_mcast_log_fd = -1;
+		debugf(NHRP_DEBUG_COMMON, "De-register nflog group");
+	}
+	netlink_mcast_nflog_group = nlgroup;
+	if (nlgroup) {
+		netlink_mcast_log_fd = znl_open(NETLINK_NETFILTER, 0);
+		if (netlink_mcast_log_fd < 0)
+			return;
+
+		netlink_mcast_log_register(netlink_mcast_log_fd, nlgroup);
+		thread_add_read(master, netlink_mcast_log_recv, 0,
+				netlink_mcast_log_fd,
+				&netlink_mcast_log_thread);
+		debugf(NHRP_DEBUG_COMMON, "Register nflog group: %d",
+		       netlink_mcast_nflog_group);
+	}
+}
+
+static int nhrp_multicast_free(struct interface *ifp,
+			       struct nhrp_multicast *mcast)
+{
+	list_del(&mcast->list_entry);
+	XFREE(MTYPE_NHRP_MULTICAST, mcast);
+	return 0;
+}
+
+int nhrp_multicast_add(struct interface *ifp, afi_t afi,
+		       union sockunion *nbma_addr)
+{
+	struct nhrp_interface *nifp = ifp->info;
+	struct nhrp_multicast *mcast;
+
+	list_for_each_entry(mcast, &nifp->afi[afi].mcastlist_head, list_entry)
+	{
+		if (sockunion_same(&mcast->nbma_addr, nbma_addr))
+			return NHRP_ERR_ENTRY_EXISTS;
+	}
+
+	mcast = XMALLOC(MTYPE_NHRP_MULTICAST, sizeof(struct nhrp_multicast));
+
+	*mcast = (struct nhrp_multicast){
+		.afi = afi, .ifp = ifp, .nbma_addr = *nbma_addr,
+	};
+	list_add_tail(&mcast->list_entry, &nifp->afi[afi].mcastlist_head);
+
+	debugf(NHRP_DEBUG_COMMON, "Adding multicast entry (%pSU)", nbma_addr);
+
+	return NHRP_OK;
+}
+
+int nhrp_multicast_del(struct interface *ifp, afi_t afi,
+		       union sockunion *nbma_addr)
+{
+	struct nhrp_interface *nifp = ifp->info;
+	struct nhrp_multicast *mcast, *tmp;
+
+	list_for_each_entry_safe(mcast, tmp, &nifp->afi[afi].mcastlist_head,
+				 list_entry)
+	{
+		if (!sockunion_same(&mcast->nbma_addr, nbma_addr))
+			continue;
+
+		debugf(NHRP_DEBUG_COMMON, "Deleting multicast entry (%pSU)",
+		       nbma_addr);
+
+		nhrp_multicast_free(ifp, mcast);
+
+		return NHRP_OK;
+	}
+
+	return NHRP_ERR_ENTRY_NOT_FOUND;
+}
+
+void nhrp_multicast_interface_del(struct interface *ifp)
+{
+	struct nhrp_interface *nifp = ifp->info;
+	struct nhrp_multicast *mcast, *tmp;
+	afi_t afi;
+
+	for (afi = 0; afi < AFI_MAX; afi++) {
+		debugf(NHRP_DEBUG_COMMON,
+		       "Cleaning up multicast entries (%d)",
+		       !list_empty(&nifp->afi[afi].mcastlist_head));
+
+		list_for_each_entry_safe(
+			mcast, tmp, &nifp->afi[afi].mcastlist_head, list_entry)
+		{
+			nhrp_multicast_free(ifp, mcast);
+		}
+	}
+}
+
+void nhrp_multicast_foreach(struct interface *ifp, afi_t afi,
+			    void (*cb)(struct nhrp_multicast *, void *),
+			    void *ctx)
+{
+	struct nhrp_interface *nifp = ifp->info;
+	struct nhrp_multicast *mcast;
+
+	list_for_each_entry(mcast, &nifp->afi[afi].mcastlist_head, list_entry)
+	{
+		cb(mcast, ctx);
+	}
+}
diff --git a/nhrpd/nhrp_peer.c b/nhrpd/nhrp_peer.c
index a44190d29..5a7da703a 100644
--- a/nhrpd/nhrp_peer.c
+++ b/nhrpd/nhrp_peer.c
@@ -376,7 +376,7 @@ void nhrp_peer_send(struct nhrp_peer *p, struct zbuf *zb)
 
 	os_sendmsg(zb->head, zbuf_used(zb), p->ifp->ifindex,
 		   sockunion_get_addr(&p->vc->remote.nbma),
-		   sockunion_get_addrlen(&p->vc->remote.nbma));
+		   sockunion_get_addrlen(&p->vc->remote.nbma), ETH_P_NHRP);
 	zbuf_reset(zb);
 }
 
diff --git a/nhrpd/nhrp_vty.c b/nhrpd/nhrp_vty.c
index 4358605e2..420ea12ec 100644
--- a/nhrpd/nhrp_vty.c
+++ b/nhrpd/nhrp_vty.c
@@ -187,6 +187,9 @@ static int nhrp_config_write(struct vty *vty)
 	if (netlink_nflog_group) {
 		vty_out(vty, "nhrp nflog-group %d\n", netlink_nflog_group);
 	}
+	if (netlink_mcast_nflog_group)
+		vty_out(vty, "nhrp multicast-nflog-group %d\n",
+			netlink_mcast_nflog_group);
 
 	return 0;
 }
@@ -257,6 +260,31 @@ DEFUN(no_nhrp_nflog_group, no_nhrp_nflog_group_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(nhrp_multicast_nflog_group, nhrp_multicast_nflog_group_cmd,
+	"nhrp multicast-nflog-group (1-65535)",
+	NHRP_STR
+	"Specify NFLOG group number for Multicast Packets\n"
+	"NFLOG group number\n")
+{
+	uint32_t nfgroup;
+
+	nfgroup = strtoul(argv[2]->arg, NULL, 10);
+	netlink_mcast_set_nflog_group(nfgroup);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_nhrp_multicast_nflog_group, no_nhrp_multicast_nflog_group_cmd,
+	"no nhrp multicast-nflog-group [(1-65535)]",
+	NO_STR
+	NHRP_STR
+	"Specify NFLOG group number\n"
+	"NFLOG group number\n")
+{
+	netlink_mcast_set_nflog_group(0);
+	return CMD_SUCCESS;
+}
+
 DEFUN(tunnel_protection, tunnel_protection_cmd,
 	"tunnel protection vici profile PROFILE [fallback-profile FALLBACK]",
 	"NHRP/GRE integration\n"
@@ -570,6 +598,53 @@ DEFUN(if_no_nhrp_map, if_no_nhrp_map_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(if_nhrp_map_multicast, if_nhrp_map_multicast_cmd,
+	AFI_CMD " nhrp map multicast <A.B.C.D|X:X::X:X|dynamic>",
+	AFI_STR
+	NHRP_STR
+	"Multicast NBMA Configuration\n"
+	"Use this NBMA mapping for multicasts\n"
+	"IPv4 NBMA address\n"
+	"IPv6 NBMA address\n"
+	"Dynamically learn destinations from client registrations on hub\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	afi_t afi = cmd_to_afi(argv[0]);
+	union sockunion nbma_addr;
+	int ret;
+
+	if (str2sockunion(argv[4]->arg, &nbma_addr) < 0)
+		sockunion_family(&nbma_addr) = AF_UNSPEC;
+
+	ret = nhrp_multicast_add(ifp, afi, &nbma_addr);
+
+	return nhrp_vty_return(vty, ret);
+}
+
+DEFUN(if_no_nhrp_map_multicast, if_no_nhrp_map_multicast_cmd,
+	"no " AFI_CMD " nhrp map multicast <A.B.C.D|X:X::X:X|dynamic>",
+	NO_STR
+	AFI_STR
+	NHRP_STR
+	"Multicast NBMA Configuration\n"
+	"Use this NBMA mapping for multicasts\n"
+	"IPv4 NBMA address\n"
+	"IPv6 NBMA address\n"
+	"Dynamically learn destinations from client registrations on hub\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	afi_t afi = cmd_to_afi(argv[1]);
+	union sockunion nbma_addr;
+	int ret;
+
+	if (str2sockunion(argv[5]->arg, &nbma_addr) < 0)
+		sockunion_family(&nbma_addr) = AF_UNSPEC;
+
+	ret = nhrp_multicast_del(ifp, afi, &nbma_addr);
+
+	return nhrp_vty_return(vty, ret);
+}
+
 DEFUN(if_nhrp_nhs, if_nhrp_nhs_cmd,
 	AFI_CMD " nhrp nhs <A.B.C.D|X:X::X:X|dynamic> nbma <A.B.C.D|FQDN>",
 	AFI_STR
@@ -732,8 +807,8 @@ static void show_ip_nhrp_nhs(struct nhrp_nhs *n, struct nhrp_registration *reg,
 	ctx->count++;
 
 	if (reg && reg->peer)
-		sockunion2str(&reg->peer->vc->remote.nbma,
-			      buf[0], sizeof(buf[0]));
+		sockunion2str(&reg->peer->vc->remote.nbma, buf[0],
+			      sizeof(buf[0]));
 	else
 		snprintf(buf[0], sizeof(buf[0]), "-");
 	sockunion2str(reg ? &reg->proto_addr : &n->proto_addr, buf[1],
@@ -1047,19 +1122,20 @@ struct write_map_ctx {
 	const char *aficmd;
 };
 
-static void interface_config_write_nhrp_map(struct nhrp_cache_config *c, void *data)
+static void interface_config_write_nhrp_map(struct nhrp_cache_config *c,
+					    void *data)
 {
 	struct write_map_ctx *ctx = data;
 	struct vty *vty = ctx->vty;
-	char buf[2][SU_ADDRSTRLEN];
 
 	if (sockunion_family(&c->remote_addr) != ctx->family)
 		return;
 
-	vty_out(vty, " %s nhrp map %s %s\n", ctx->aficmd,
-		sockunion2str(&c->remote_addr, buf[0], sizeof(buf[0])),
-		c->type == NHRP_CACHE_LOCAL
-		? "local" : sockunion2str(&c->nbma, buf[1], sizeof(buf[1])));
+	vty_out(vty, " %s nhrp map %pSU ", ctx->aficmd, &c->remote_addr);
+	if (c->type == NHRP_CACHE_LOCAL)
+		vty_out(vty, "local\n");
+	else
+		vty_out(vty, "%pSU\n", &c->nbma);
 }
 
 static int interface_config_write(struct vty *vty)
@@ -1069,9 +1145,9 @@ static int interface_config_write(struct vty *vty)
 	struct interface *ifp;
 	struct nhrp_interface *nifp;
 	struct nhrp_nhs *nhs;
+	struct nhrp_multicast *mcast;
 	const char *aficmd;
 	afi_t afi;
-	char buf[SU_ADDRSTRLEN];
 	int i;
 
 	FOR_ALL_INTERFACES (vrf, ifp) {
@@ -1122,21 +1198,31 @@ static int interface_config_write(struct vty *vty)
 				.family = afi2family(afi),
 				.aficmd = aficmd,
 			};
-			nhrp_cache_config_foreach(ifp, interface_config_write_nhrp_map,
-						  &mapctx);
+			nhrp_cache_config_foreach(
+				ifp, interface_config_write_nhrp_map, &mapctx);
 
 			list_for_each_entry(nhs, &ad->nhslist_head,
 					    nhslist_entry)
 			{
-				vty_out(vty, " %s nhrp nhs %s nbma %s\n",
-					aficmd,
-					sockunion_family(&nhs->proto_addr)
-							== AF_UNSPEC
-						? "dynamic"
-						: sockunion2str(
-							  &nhs->proto_addr, buf,
-							  sizeof(buf)),
-					nhs->nbma_fqdn);
+				vty_out(vty, " %s nhrp nhs ", aficmd);
+				if (sockunion_family(&nhs->proto_addr)
+				   == AF_UNSPEC)
+					vty_out(vty, "dynamic");
+				else
+					vty_out(vty, "%pSU", &nhs->proto_addr);
+				vty_out(vty, "nbma %s\n", nhs->nbma_fqdn);
+			}
+
+			list_for_each_entry(mcast, &ad->mcastlist_head,
+					    list_entry)
+			{
+				vty_out(vty, " %s nhrp map multicast ", aficmd);
+				if (sockunion_family(&mcast->nbma_addr)
+				   == AF_UNSPEC)
+					vty_out(vty, "dynamic\n");
+				else
+					vty_out(vty, "%pSU\n",
+						&mcast->nbma_addr);
 			}
 		}
 
@@ -1171,6 +1257,8 @@ void nhrp_config_init(void)
 	install_element(CONFIG_NODE, &no_nhrp_event_socket_cmd);
 	install_element(CONFIG_NODE, &nhrp_nflog_group_cmd);
 	install_element(CONFIG_NODE, &no_nhrp_nflog_group_cmd);
+	install_element(CONFIG_NODE, &nhrp_multicast_nflog_group_cmd);
+	install_element(CONFIG_NODE, &no_nhrp_multicast_nflog_group_cmd);
 
 	/* interface specific commands */
 	install_node(&nhrp_interface_node);
@@ -1192,6 +1280,8 @@ void nhrp_config_init(void)
 	install_element(INTERFACE_NODE, &if_no_nhrp_reg_flags_cmd);
 	install_element(INTERFACE_NODE, &if_nhrp_map_cmd);
 	install_element(INTERFACE_NODE, &if_no_nhrp_map_cmd);
+	install_element(INTERFACE_NODE, &if_nhrp_map_multicast_cmd);
+	install_element(INTERFACE_NODE, &if_no_nhrp_map_multicast_cmd);
 	install_element(INTERFACE_NODE, &if_nhrp_nhs_cmd);
 	install_element(INTERFACE_NODE, &if_no_nhrp_nhs_cmd);
 }
diff --git a/nhrpd/nhrpd.h b/nhrpd/nhrpd.h
index 136f855df..730f9b7d1 100644
--- a/nhrpd/nhrpd.h
+++ b/nhrpd/nhrpd.h
@@ -269,6 +269,13 @@ struct nhrp_nhs {
 	struct list_head reglist_head;
 };
 
+struct nhrp_multicast {
+	struct interface *ifp;
+	struct list_head list_entry;
+	afi_t afi;
+	union sockunion nbma_addr; /* IP-address */
+};
+
 struct nhrp_registration {
 	struct list_head reglist_entry;
 	struct thread *t_register;
@@ -314,6 +321,7 @@ struct nhrp_interface {
 		unsigned short mtu;
 		unsigned int holdtime;
 		struct list_head nhslist_head;
+		struct list_head mcastlist_head;
 	} afi[AFI_MAX];
 };
 
@@ -356,6 +364,16 @@ void nhrp_nhs_foreach(struct interface *ifp, afi_t afi,
 		      void *ctx);
 void nhrp_nhs_interface_del(struct interface *ifp);
 
+int nhrp_multicast_add(struct interface *ifp, afi_t afi,
+		       union sockunion *nbma_addr);
+int nhrp_multicast_del(struct interface *ifp, afi_t afi,
+		       union sockunion *nbma_addr);
+void nhrp_multicast_interface_del(struct interface *ifp);
+void nhrp_multicast_foreach(struct interface *ifp, afi_t afi,
+			    void (*cb)(struct nhrp_multicast *, void *),
+			    void *ctx);
+void netlink_mcast_set_nflog_group(int nlgroup);
+
 void nhrp_route_update_nhrp(const struct prefix *p, struct interface *ifp);
 void nhrp_route_announce(int add, enum nhrp_cache_type type,
 			 const struct prefix *p, struct interface *ifp,
diff --git a/nhrpd/os.h b/nhrpd/os.h
index dd65d3cbe..2b9e07fa6 100644
--- a/nhrpd/os.h
+++ b/nhrpd/os.h
@@ -1,7 +1,7 @@
 
 int os_socket(void);
 int os_sendmsg(const uint8_t *buf, size_t len, int ifindex, const uint8_t *addr,
-	       size_t addrlen);
+	       size_t addrlen, uint16_t protocol);
 int os_recvmsg(uint8_t *buf, size_t *len, int *ifindex, uint8_t *addr,
 	       size_t *addrlen);
 int os_configure_dmvpn(unsigned int ifindex, const char *ifname, int af);
diff --git a/nhrpd/subdir.am b/nhrpd/subdir.am
index 61b1fe31b..d00aecc1e 100644
--- a/nhrpd/subdir.am
+++ b/nhrpd/subdir.am
@@ -22,6 +22,7 @@ nhrpd_nhrpd_SOURCES = \
 	nhrpd/nhrp_nhs.c \
 	nhrpd/nhrp_packet.c \
 	nhrpd/nhrp_peer.c \
+	nhrpd/nhrp_multicast.c \
 	nhrpd/nhrp_route.c \
 	nhrpd/nhrp_shortcut.c \
 	nhrpd/nhrp_vc.c \