diff --git a/nhrpd/netlink_gre.c b/nhrpd/netlink_gre.c
new file mode 100644
index 0000000..7cd30aa
--- /dev/null
+++ b/nhrpd/netlink_gre.c
@@ -0,0 +1,141 @@
+/* NHRP netlink/GRE tunnel configuration code
+ * Copyright (c) 2014-2016 Timo Teräs
+ *
+ * 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.
+ */
+
+#include <netinet/in.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/if_tunnel.h>
+
+#include "debug.h"
+#include "netlink.h"
+#include "znl.h"
+
+static int __netlink_gre_get_data(struct zbuf *zb, struct zbuf *data, int ifindex)
+{
+	struct nlmsghdr *n;
+	struct ifinfomsg *ifi;
+	struct zbuf payload, rtapayload;
+	struct rtattr *rta;
+
+	debugf(NHRP_DEBUG_KERNEL, "netlink-link-gre: get-info %u", ifindex);
+
+	n = znl_nlmsg_push(zb, RTM_GETLINK, NLM_F_REQUEST);
+	ifi = znl_push(zb, sizeof(*ifi));
+	*ifi = (struct ifinfomsg) {
+		.ifi_index = ifindex,
+	};
+	znl_nlmsg_complete(zb, n);
+
+	if (zbuf_send(zb, netlink_req_fd) < 0 ||
+	    zbuf_recv(zb, netlink_req_fd) < 0)
+		return -1;
+
+	n = znl_nlmsg_pull(zb, &payload);
+	if (!n) return -1;
+
+	if (n->nlmsg_type != RTM_NEWLINK)
+		return -1;
+
+	ifi = znl_pull(&payload, sizeof(struct ifinfomsg));
+	if (!ifi)
+		return -1;
+
+	debugf(NHRP_DEBUG_KERNEL, "netlink-link-gre: ifindex %u, receive msg_type %u, msg_flags %u",
+		ifi->ifi_index, n->nlmsg_type, n->nlmsg_flags);
+
+	if (ifi->ifi_index != ifindex)
+		return -1;
+
+	while ((rta = znl_rta_pull(&payload, &rtapayload)) != NULL)
+		if (rta->rta_type == IFLA_LINKINFO)
+			break;
+	if (!rta) return -1;
+
+	payload = rtapayload;
+	while ((rta = znl_rta_pull(&payload, &rtapayload)) != NULL)
+		if (rta->rta_type == IFLA_INFO_DATA)
+			break;
+	if (!rta) return -1;
+
+	*data = rtapayload;
+	return 0;
+}
+
+void netlink_gre_get_info(unsigned int ifindex, uint32_t *gre_key, unsigned int *link_index, struct in_addr *saddr)
+{
+	struct zbuf *zb = zbuf_alloc(8192), data, rtapl;
+	struct rtattr *rta;
+
+	*link_index = 0;
+	*gre_key = 0;
+	saddr->s_addr = 0;
+
+	if (__netlink_gre_get_data(zb, &data, ifindex) < 0)
+		goto err;
+
+	while ((rta = znl_rta_pull(&data, &rtapl)) != NULL) {
+		switch (rta->rta_type) {
+		case IFLA_GRE_LINK:
+			*link_index = zbuf_get32(&rtapl);
+			break;
+		case IFLA_GRE_IKEY:
+		case IFLA_GRE_OKEY:
+			*gre_key = zbuf_get32(&rtapl);
+			break;
+		case IFLA_GRE_LOCAL:
+			saddr->s_addr = zbuf_get32(&rtapl);
+			break;
+		}
+	}
+err:
+	zbuf_free(zb);
+}
+
+void netlink_gre_set_link(unsigned int ifindex, unsigned int link_index)
+{
+	struct nlmsghdr *n;
+	struct ifinfomsg *ifi;
+	struct rtattr *rta_info, *rta_data, *rta;
+	struct zbuf *zr = zbuf_alloc(8192), data, rtapl;
+	struct zbuf *zb = zbuf_alloc(8192);
+	size_t len;
+
+	if (__netlink_gre_get_data(zr, &data, ifindex) < 0)
+		goto err;
+
+	n = znl_nlmsg_push(zb, RTM_NEWLINK, NLM_F_REQUEST);
+	ifi = znl_push(zb, sizeof(*ifi));
+	*ifi = (struct ifinfomsg) {
+		.ifi_index = ifindex,
+	};
+	rta_info = znl_rta_nested_push(zb, IFLA_LINKINFO);
+	znl_rta_push(zb, IFLA_INFO_KIND, "gre", 3);
+	rta_data = znl_rta_nested_push(zb, IFLA_INFO_DATA);
+
+	znl_rta_push_u32(zb, IFLA_GRE_LINK, link_index);
+	while ((rta = znl_rta_pull(&data, &rtapl)) != NULL) {
+		if (rta->rta_type == IFLA_GRE_LINK)
+			continue;
+		len = zbuf_used(&rtapl);
+		znl_rta_push(zb, rta->rta_type, zbuf_pulln(&rtapl, len), len);
+	}
+
+	znl_rta_nested_complete(zb, rta_data);
+	znl_rta_nested_complete(zb, rta_info);
+
+	znl_nlmsg_complete(zb, n);
+	zbuf_send(zb, netlink_req_fd);
+	zbuf_recv(zb, netlink_req_fd);
+err:
+	zbuf_free(zb);
+	zbuf_free(zr);
+}