nhrpd/nhrp_nhs.c - quagga - Gitiles

 /* NHRP NHC nexthop server functions (registration)
  * Copyright (c) 2014-2015 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 "zebra.h"
 #include "zbuf.h"
 #include "memory.h"
 #include "thread.h"
 #include "nhrpd.h"
 #include "nhrp_protocol.h"

 static int nhrp_nhs_resolve(struct thread *t);

 struct nhrp_registration {
 	struct list_head reglist_entry;
 	struct thread *t_register;
 	struct nhrp_nhs *nhs;
 	struct nhrp_reqid reqid;
 	unsigned int timeout;
 	unsigned mark : 1;
 	union sockunion proto_addr;
 	struct nhrp_peer *peer;
 	struct notifier_block peer_notifier;
 };

 static int nhrp_reg_send_req(struct thread *t);

 static void nhrp_reg_reply(struct nhrp_reqid *reqid, void *arg)
 {
 	struct nhrp_packet_parser *p = arg;
 	struct nhrp_registration *r = container_of(reqid, struct nhrp_registration, reqid);
 	struct nhrp_nhs *nhs = r->nhs;
 	struct interface *ifp = nhs->ifp;
 	struct nhrp_interface *nifp = ifp->info;
 	struct nhrp_extension_header *ext;
 	struct nhrp_cie_header *cie;
 	struct nhrp_cache *c;
 	struct zbuf extpl;
 	union sockunion cie_nbma, cie_proto, *proto;
 	char buf[64];
 	int ok = 0, holdtime;

 	nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);

 	if (p->hdr->type != NHRP_PACKET_REGISTRATION_REPLY) {
 		debugf(NHRP_DEBUG_COMMON, "NHS: Registration failed");
 		return;
 	}

 	debugf(NHRP_DEBUG_COMMON, "NHS: Reg.reply received");

 	ok = 1;
 	while ((cie = nhrp_cie_pull(&p->payload, p->hdr, &cie_nbma, &cie_proto)) != NULL) {
 		proto = sockunion_family(&cie_proto) != AF_UNSPEC ? &cie_proto : &p->src_proto;
 		debugf(NHRP_DEBUG_COMMON, "NHS: CIE registration: %s: %d",
 			sockunion2str(proto, buf, sizeof(buf)),
 			cie->code);
 		if (!((cie->code == NHRP_CODE_SUCCESS) ||
                       (cie->code == NHRP_CODE_ADMINISTRATIVELY_PROHIBITED && nhs->hub)))
 			ok = 0;
 	}

 	if (!ok)
 		return;

 	/* Parse extensions */
 	sockunion_family(&nifp->nat_nbma) = AF_UNSPEC;
 	while ((ext = nhrp_ext_pull(&p->extensions, &extpl)) != NULL) {
 		switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
 		case NHRP_EXTENSION_NAT_ADDRESS:
 			/* NHS adds second CIE if NAT is detected */
 			if (nhrp_cie_pull(&extpl, p->hdr, &cie_nbma, &cie_proto) &&
 			    nhrp_cie_pull(&extpl, p->hdr, &cie_nbma, &cie_proto)) {
 				nifp->nat_nbma = cie_nbma;
 				debugf(NHRP_DEBUG_IF, "%s: NAT detected, real NBMA address: %s",
 					ifp->name, sockunion2str(&nifp->nbma, buf, sizeof(buf)));
 			}
 			break;
 		}
 	}

 	/* Success - schedule next registration, and route NHS */
 	r->timeout = 2;
 	holdtime = nifp->afi[nhs->afi].holdtime;
 	THREAD_OFF(r->t_register);

 	/* RFC 2332 5.2.3 - Registration is recommend to be renewed
 	 * every one third of holdtime */
 	THREAD_TIMER_ON(master, r->t_register, nhrp_reg_send_req, r, holdtime / 3);

 	r->proto_addr = p->dst_proto;
 	c = nhrp_cache_get(ifp, &p->dst_proto, 1);
 	if (c) nhrp_cache_update_binding(c, NHRP_CACHE_NHS, holdtime, nhrp_peer_ref(r->peer), 0, NULL);
 }

 static int nhrp_reg_timeout(struct thread *t)
 {
 	struct nhrp_registration *r = THREAD_ARG(t);
 	struct nhrp_cache *c;

 	r->t_register = NULL;

 	if (r->timeout >= 16 && sockunion_family(&r->proto_addr) != AF_UNSPEC) {
 		nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);
 		c = nhrp_cache_get(r->nhs->ifp, &r->proto_addr, 0);
 		if (c) nhrp_cache_update_binding(c, NHRP_CACHE_NHS, -1, NULL, 0, NULL);
 		sockunion_family(&r->proto_addr) = AF_UNSPEC;
 	}

 	r->timeout <<= 1;
 	if (r->timeout > 64) r->timeout = 2;
 	THREAD_TIMER_MSEC_ON(master, r->t_register, nhrp_reg_send_req, r, 10);

 	return 0;
 }

 static void nhrp_reg_peer_notify(struct notifier_block *n, unsigned long cmd)
 {
 	struct nhrp_registration *r = container_of(n, struct nhrp_registration, peer_notifier);
 	char buf[SU_ADDRSTRLEN];

 	switch (cmd) {
 	case NOTIFY_PEER_UP:
 	case NOTIFY_PEER_DOWN:
 	case NOTIFY_PEER_IFCONFIG_CHANGED:
 	case NOTIFY_PEER_MTU_CHANGED:
 		debugf(NHRP_DEBUG_COMMON, "NHS: Flush timer for %s",
 			sockunion2str(&r->peer->vc->remote.nbma, buf, sizeof buf));
 		THREAD_TIMER_OFF(r->t_register);
 		THREAD_TIMER_MSEC_ON(master, r->t_register, nhrp_reg_send_req, r, 10);
 		break;
 	}
 }

 static int nhrp_reg_send_req(struct thread *t)
 {
 	struct nhrp_registration *r = THREAD_ARG(t);
 	struct nhrp_nhs *nhs = r->nhs;
 	char buf1[SU_ADDRSTRLEN], buf2[SU_ADDRSTRLEN];
 	struct interface *ifp = nhs->ifp;
 	struct nhrp_interface *nifp = ifp->info;
 	struct nhrp_afi_data *if_ad = &nifp->afi[nhs->afi];
 	union sockunion *dst_proto;
 	struct zbuf *zb;
 	struct nhrp_packet_header *hdr;
 	struct nhrp_extension_header *ext;
 	struct nhrp_cie_header *cie;

 	r->t_register = NULL;
 	if (!nhrp_peer_check(r->peer, 2)) {
 		debugf(NHRP_DEBUG_COMMON, "NHS: Waiting link for %s",
 			sockunion2str(&r->peer->vc->remote.nbma, buf1, sizeof buf1));
 		THREAD_TIMER_ON(master, r->t_register, nhrp_reg_send_req, r, 120);
 		return 0;
 	}

 	THREAD_TIMER_ON(master, r->t_register, nhrp_reg_timeout, r, r->timeout);

 	/* RFC2332 5.2.3 NHC uses it's own address as dst if NHS is unknown */
 	dst_proto = &nhs->proto_addr;
 	if (sockunion_family(dst_proto) == AF_UNSPEC)
 		dst_proto = &if_ad->addr;

 	sockunion2str(&if_ad->addr, buf1, sizeof(buf1));
 	sockunion2str(dst_proto, buf2, sizeof(buf2));
 	debugf(NHRP_DEBUG_COMMON, "NHS: Register %s -> %s (timeout %d)", buf1, buf2, r->timeout);

 	/* No protocol address configured for tunnel interface */
 	if (sockunion_family(&if_ad->addr) == AF_UNSPEC)
 		return 0;

 	zb = zbuf_alloc(1400);
 	hdr = nhrp_packet_push(zb, NHRP_PACKET_REGISTRATION_REQUEST, &nifp->nbma, &if_ad->addr, dst_proto);
 	hdr->hop_count = 0;
 	if (!(if_ad->flags & NHRP_IFF_REG_NO_UNIQUE))
 		hdr->flags |= htons(NHRP_FLAG_REGISTRATION_UNIQUE);

 	hdr->u.request_id = htonl(nhrp_reqid_alloc(&nhrp_packet_reqid, &r->reqid, nhrp_reg_reply));

 	/* FIXME: push CIE for each local protocol address */
 	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, NULL, NULL);
 	cie->prefix_length = 0xff;
 	cie->holding_time = htons(if_ad->holdtime);
 	cie->mtu = htons(if_ad->mtu);

 	nhrp_ext_request(zb, hdr, ifp);

 	/* Cisco NAT detection extension */
 	hdr->flags |= htons(NHRP_FLAG_REGISTRATION_NAT);
 	ext = nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
 	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, &nifp->nbma, &if_ad->addr);
 	cie->prefix_length = 8 * sockunion_get_addrlen(&nifp->nbma);
 	nhrp_ext_complete(zb, ext);

 	nhrp_packet_complete(zb, hdr);
 	nhrp_peer_send(r->peer, zb);
 	zbuf_free(zb);

 	return 0;
 }

 static void nhrp_reg_delete(struct nhrp_registration *r)
 {
 	nhrp_peer_notify_del(r->peer, &r->peer_notifier);
 	nhrp_peer_unref(r->peer);
 	list_del(&r->reglist_entry);
 	THREAD_OFF(r->t_register);
 	XFREE(MTYPE_NHRP_REGISTRATION, r);
 }

 static struct nhrp_registration *nhrp_reg_by_nbma(struct nhrp_nhs *nhs, const union sockunion *nbma_addr)
 {
 	struct nhrp_registration *r;

 	list_for_each_entry(r, &nhs->reglist_head, reglist_entry)
 		if (sockunion_same(&r->peer->vc->remote.nbma, nbma_addr))
 			return r;
 	return NULL;
 }

 static void nhrp_nhs_resolve_cb(struct resolver_query *q, int n, union sockunion *addrs)
 {
 	struct nhrp_nhs *nhs = container_of(q, struct nhrp_nhs, dns_resolve);
 	struct nhrp_interface *nifp = nhs->ifp->info;
 	struct nhrp_registration *reg, *regn;
 	int i;

 	nhs->t_resolve = NULL;
 	if (n < 0) {
 		/* Failed, retry in a moment */
 		THREAD_TIMER_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 5);
 		return;
 	}

 	THREAD_TIMER_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 2*60*60);

 	list_for_each_entry(reg, &nhs->reglist_head, reglist_entry)
 		reg->mark = 1;

 	nhs->hub = 0;
 	for (i = 0; i < n; i++) {
 		if (sockunion_same(&addrs[i], &nifp->nbma)) {
 			nhs->hub = 1;
 			continue;
 		}

 		reg = nhrp_reg_by_nbma(nhs, &addrs[i]);
 		if (reg) {
 			reg->mark = 0;
 			continue;
 		}

 		reg = XCALLOC(MTYPE_NHRP_REGISTRATION, sizeof(*reg));
 		reg->peer = nhrp_peer_get(nhs->ifp, &addrs[i]);
 		reg->nhs = nhs;
 		reg->timeout = 1;
 		list_init(&reg->reglist_entry);
 		list_add_tail(&reg->reglist_entry, &nhs->reglist_head);
 		nhrp_peer_notify_add(reg->peer, &reg->peer_notifier, nhrp_reg_peer_notify);
 		THREAD_TIMER_MSEC_ON(master, reg->t_register, nhrp_reg_send_req, reg, 50);
 	}

 	list_for_each_entry_safe(reg, regn, &nhs->reglist_head, reglist_entry) {
 		if (reg->mark)
 			nhrp_reg_delete(reg);
 	}
 }

 static int nhrp_nhs_resolve(struct thread *t)
 {
 	struct nhrp_nhs *nhs = THREAD_ARG(t);

 	resolver_resolve(&nhs->dns_resolve, AF_INET, nhs->nbma_fqdn, nhrp_nhs_resolve_cb);

 	return 0;
 }

 int nhrp_nhs_add(struct interface *ifp, afi_t afi, union sockunion *proto_addr, const char *nbma_fqdn)
 {
 	struct nhrp_interface *nifp = ifp->info;
 	struct nhrp_nhs *nhs;

 	if (sockunion_family(proto_addr) != AF_UNSPEC &&
 	    sockunion_family(proto_addr) != afi2family(afi))
 		return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;

 	list_for_each_entry(nhs, &nifp->afi[afi].nhslist_head, nhslist_entry) {
 		if (sockunion_family(&nhs->proto_addr) != AF_UNSPEC &&
 		    sockunion_family(proto_addr) != AF_UNSPEC &&
 		    sockunion_same(&nhs->proto_addr, proto_addr))
 			return NHRP_ERR_ENTRY_EXISTS;

 		if (strcmp(nhs->nbma_fqdn, nbma_fqdn) == 0)
 			return NHRP_ERR_ENTRY_EXISTS;
 	}

 	nhs = XMALLOC(MTYPE_NHRP_NHS, sizeof(struct nhrp_nhs));
 	if (!nhs) return NHRP_ERR_NO_MEMORY;

 	*nhs = (struct nhrp_nhs) {
 		.afi = afi,
 		.ifp = ifp,
 		.proto_addr = *proto_addr,
 		.nbma_fqdn = strdup(nbma_fqdn),
 		.reglist_head = LIST_INITIALIZER(nhs->reglist_head),
 	};
 	list_add_tail(&nhs->nhslist_entry, &nifp->afi[afi].nhslist_head);
 	THREAD_TIMER_MSEC_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 1000);

 	return NHRP_OK;
 }

 int nhrp_nhs_del(struct interface *ifp, afi_t afi, union sockunion *proto_addr, const char *nbma_fqdn)
 {
 	struct nhrp_interface *nifp = ifp->info;
 	struct nhrp_nhs *nhs, *nnhs;
 	int ret = NHRP_ERR_ENTRY_NOT_FOUND;

 	if (sockunion_family(proto_addr) != AF_UNSPEC &&
 	    sockunion_family(proto_addr) != afi2family(afi))
 		return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;

 	list_for_each_entry_safe(nhs, nnhs, &nifp->afi[afi].nhslist_head, nhslist_entry) {
 		if (!sockunion_same(&nhs->proto_addr, proto_addr))
 			continue;
 		if (strcmp(nhs->nbma_fqdn, nbma_fqdn) != 0)
 			continue;

 		nhrp_nhs_free(nhs);
 		ret = NHRP_OK;
 	}

 	return ret;
 }

 int nhrp_nhs_free(struct nhrp_nhs *nhs)
 {
 	struct nhrp_registration *r, *rn;

 	list_for_each_entry_safe(r, rn, &nhs->reglist_head, reglist_entry)
 		nhrp_reg_delete(r);
 	THREAD_OFF(nhs->t_resolve);
 	list_del(&nhs->nhslist_entry);
 	free((void*) nhs->nbma_fqdn);
 	XFREE(MTYPE_NHRP_NHS, nhs);
 	return 0;
 }

 void nhrp_nhs_terminate(void)
 {
 	struct interface *ifp;
 	struct nhrp_interface *nifp;
 	struct nhrp_nhs *nhs, *tmp;
 	struct listnode *node;
 	afi_t afi;

 	for (ALL_LIST_ELEMENTS_RO(iflist, node, ifp)) {
 		nifp = ifp->info;
 		for (afi = 0; afi < AFI_MAX; afi++) {
 			list_for_each_entry_safe(nhs, tmp, &nifp->afi[afi].nhslist_head, nhslist_entry)
 				nhrp_nhs_free(nhs);
 		}
 	}
 }
	/* NHRP NHC nexthop server functions (registration)
	* Copyright (c) 2014-2015 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 "zebra.h"
	#include "zbuf.h"
	#include "memory.h"
	#include "thread.h"
	#include "nhrpd.h"
	#include "nhrp_protocol.h"

	static int nhrp_nhs_resolve(struct thread *t);

	struct nhrp_registration {
	struct list_head reglist_entry;
	struct thread *t_register;
	struct nhrp_nhs *nhs;
	struct nhrp_reqid reqid;
	unsigned int timeout;
	unsigned mark : 1;
	union sockunion proto_addr;
	struct nhrp_peer *peer;
	struct notifier_block peer_notifier;
	};

	static int nhrp_reg_send_req(struct thread *t);

	static void nhrp_reg_reply(struct nhrp_reqid reqid, void arg)
	{
	struct nhrp_packet_parser *p = arg;
	struct nhrp_registration *r = container_of(reqid, struct nhrp_registration, reqid);
	struct nhrp_nhs *nhs = r->nhs;
	struct interface *ifp = nhs->ifp;
	struct nhrp_interface *nifp = ifp->info;
	struct nhrp_extension_header *ext;
	struct nhrp_cie_header *cie;
	struct nhrp_cache *c;
	struct zbuf extpl;
	union sockunion cie_nbma, cie_proto, *proto;
	char buf[64];
	int ok = 0, holdtime;

	nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);

	if (p->hdr->type != NHRP_PACKET_REGISTRATION_REPLY) {
	debugf(NHRP_DEBUG_COMMON, "NHS: Registration failed");
	return;
	}

	debugf(NHRP_DEBUG_COMMON, "NHS: Reg.reply received");

	ok = 1;
	while ((cie = nhrp_cie_pull(&p->payload, p->hdr, &cie_nbma, &cie_proto)) != NULL) {
	proto = sockunion_family(&cie_proto) != AF_UNSPEC ? &cie_proto : &p->src_proto;
	debugf(NHRP_DEBUG_COMMON, "NHS: CIE registration: %s: %d",
	sockunion2str(proto, buf, sizeof(buf)),
	cie->code);
	if (!((cie->code == NHRP_CODE_SUCCESS) \|\|
	(cie->code == NHRP_CODE_ADMINISTRATIVELY_PROHIBITED && nhs->hub)))
	ok = 0;
	}

	if (!ok)
	return;

	/* Parse extensions */
	sockunion_family(&nifp->nat_nbma) = AF_UNSPEC;
	while ((ext = nhrp_ext_pull(&p->extensions, &extpl)) != NULL) {
	switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
	case NHRP_EXTENSION_NAT_ADDRESS:
	/* NHS adds second CIE if NAT is detected */
	if (nhrp_cie_pull(&extpl, p->hdr, &cie_nbma, &cie_proto) &&
	nhrp_cie_pull(&extpl, p->hdr, &cie_nbma, &cie_proto)) {
	nifp->nat_nbma = cie_nbma;
	debugf(NHRP_DEBUG_IF, "%s: NAT detected, real NBMA address: %s",
	ifp->name, sockunion2str(&nifp->nbma, buf, sizeof(buf)));
	}
	break;
	}
	}

	/* Success - schedule next registration, and route NHS */
	r->timeout = 2;
	holdtime = nifp->afi[nhs->afi].holdtime;
	THREAD_OFF(r->t_register);

	/* RFC 2332 5.2.3 - Registration is recommend to be renewed
	* every one third of holdtime */
	THREAD_TIMER_ON(master, r->t_register, nhrp_reg_send_req, r, holdtime / 3);

	r->proto_addr = p->dst_proto;
	c = nhrp_cache_get(ifp, &p->dst_proto, 1);
	if (c) nhrp_cache_update_binding(c, NHRP_CACHE_NHS, holdtime, nhrp_peer_ref(r->peer), 0, NULL);
	}

	static int nhrp_reg_timeout(struct thread *t)
	{
	struct nhrp_registration *r = THREAD_ARG(t);
	struct nhrp_cache *c;

	r->t_register = NULL;

	if (r->timeout >= 16 && sockunion_family(&r->proto_addr) != AF_UNSPEC) {
	nhrp_reqid_free(&nhrp_packet_reqid, &r->reqid);
	c = nhrp_cache_get(r->nhs->ifp, &r->proto_addr, 0);
	if (c) nhrp_cache_update_binding(c, NHRP_CACHE_NHS, -1, NULL, 0, NULL);
	sockunion_family(&r->proto_addr) = AF_UNSPEC;
	}

	r->timeout <<= 1;
	if (r->timeout > 64) r->timeout = 2;
	THREAD_TIMER_MSEC_ON(master, r->t_register, nhrp_reg_send_req, r, 10);

	return 0;
	}

	static void nhrp_reg_peer_notify(struct notifier_block *n, unsigned long cmd)
	{
	struct nhrp_registration *r = container_of(n, struct nhrp_registration, peer_notifier);
	char buf[SU_ADDRSTRLEN];

	switch (cmd) {
	case NOTIFY_PEER_UP:
	case NOTIFY_PEER_DOWN:
	case NOTIFY_PEER_IFCONFIG_CHANGED:
	case NOTIFY_PEER_MTU_CHANGED:
	debugf(NHRP_DEBUG_COMMON, "NHS: Flush timer for %s",
	sockunion2str(&r->peer->vc->remote.nbma, buf, sizeof buf));
	THREAD_TIMER_OFF(r->t_register);
	THREAD_TIMER_MSEC_ON(master, r->t_register, nhrp_reg_send_req, r, 10);
	break;
	}
	}

	static int nhrp_reg_send_req(struct thread *t)
	{
	struct nhrp_registration *r = THREAD_ARG(t);
	struct nhrp_nhs *nhs = r->nhs;
	char buf1[SU_ADDRSTRLEN], buf2[SU_ADDRSTRLEN];
	struct interface *ifp = nhs->ifp;
	struct nhrp_interface *nifp = ifp->info;
	struct nhrp_afi_data *if_ad = &nifp->afi[nhs->afi];
	union sockunion *dst_proto;
	struct zbuf *zb;
	struct nhrp_packet_header *hdr;
	struct nhrp_extension_header *ext;
	struct nhrp_cie_header *cie;

	r->t_register = NULL;
	if (!nhrp_peer_check(r->peer, 2)) {
	debugf(NHRP_DEBUG_COMMON, "NHS: Waiting link for %s",
	sockunion2str(&r->peer->vc->remote.nbma, buf1, sizeof buf1));
	THREAD_TIMER_ON(master, r->t_register, nhrp_reg_send_req, r, 120);
	return 0;
	}

	THREAD_TIMER_ON(master, r->t_register, nhrp_reg_timeout, r, r->timeout);

	/* RFC2332 5.2.3 NHC uses it's own address as dst if NHS is unknown */
	dst_proto = &nhs->proto_addr;
	if (sockunion_family(dst_proto) == AF_UNSPEC)
	dst_proto = &if_ad->addr;

	sockunion2str(&if_ad->addr, buf1, sizeof(buf1));
	sockunion2str(dst_proto, buf2, sizeof(buf2));
	debugf(NHRP_DEBUG_COMMON, "NHS: Register %s -> %s (timeout %d)", buf1, buf2, r->timeout);

	/* No protocol address configured for tunnel interface */
	if (sockunion_family(&if_ad->addr) == AF_UNSPEC)
	return 0;

	zb = zbuf_alloc(1400);
	hdr = nhrp_packet_push(zb, NHRP_PACKET_REGISTRATION_REQUEST, &nifp->nbma, &if_ad->addr, dst_proto);
	hdr->hop_count = 0;
	if (!(if_ad->flags & NHRP_IFF_REG_NO_UNIQUE))
	hdr->flags \|= htons(NHRP_FLAG_REGISTRATION_UNIQUE);

	hdr->u.request_id = htonl(nhrp_reqid_alloc(&nhrp_packet_reqid, &r->reqid, nhrp_reg_reply));

	/* FIXME: push CIE for each local protocol address */
	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, NULL, NULL);
	cie->prefix_length = 0xff;
	cie->holding_time = htons(if_ad->holdtime);
	cie->mtu = htons(if_ad->mtu);

	nhrp_ext_request(zb, hdr, ifp);

	/* Cisco NAT detection extension */
	hdr->flags \|= htons(NHRP_FLAG_REGISTRATION_NAT);
	ext = nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, &nifp->nbma, &if_ad->addr);
	cie->prefix_length = 8 * sockunion_get_addrlen(&nifp->nbma);
	nhrp_ext_complete(zb, ext);

	nhrp_packet_complete(zb, hdr);
	nhrp_peer_send(r->peer, zb);
	zbuf_free(zb);

	return 0;
	}

	static void nhrp_reg_delete(struct nhrp_registration *r)
	{
	nhrp_peer_notify_del(r->peer, &r->peer_notifier);
	nhrp_peer_unref(r->peer);
	list_del(&r->reglist_entry);
	THREAD_OFF(r->t_register);
	XFREE(MTYPE_NHRP_REGISTRATION, r);
	}

	static struct nhrp_registration nhrp_reg_by_nbma(struct nhrp_nhs nhs, const union sockunion *nbma_addr)
	{
	struct nhrp_registration *r;

	list_for_each_entry(r, &nhs->reglist_head, reglist_entry)
	if (sockunion_same(&r->peer->vc->remote.nbma, nbma_addr))
	return r;
	return NULL;
	}

	static void nhrp_nhs_resolve_cb(struct resolver_query q, int n, union sockunion addrs)
	{
	struct nhrp_nhs *nhs = container_of(q, struct nhrp_nhs, dns_resolve);
	struct nhrp_interface *nifp = nhs->ifp->info;
	struct nhrp_registration reg, regn;
	int i;

	nhs->t_resolve = NULL;
	if (n < 0) {
	/* Failed, retry in a moment */
	THREAD_TIMER_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 5);
	return;
	}

	THREAD_TIMER_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 26060);

	list_for_each_entry(reg, &nhs->reglist_head, reglist_entry)
	reg->mark = 1;

	nhs->hub = 0;
	for (i = 0; i < n; i++) {
	if (sockunion_same(&addrs[i], &nifp->nbma)) {
	nhs->hub = 1;
	continue;
	}

	reg = nhrp_reg_by_nbma(nhs, &addrs[i]);
	if (reg) {
	reg->mark = 0;
	continue;
	}

	reg = XCALLOC(MTYPE_NHRP_REGISTRATION, sizeof(*reg));
	reg->peer = nhrp_peer_get(nhs->ifp, &addrs[i]);
	reg->nhs = nhs;
	reg->timeout = 1;
	list_init(&reg->reglist_entry);
	list_add_tail(&reg->reglist_entry, &nhs->reglist_head);
	nhrp_peer_notify_add(reg->peer, &reg->peer_notifier, nhrp_reg_peer_notify);
	THREAD_TIMER_MSEC_ON(master, reg->t_register, nhrp_reg_send_req, reg, 50);
	}

	list_for_each_entry_safe(reg, regn, &nhs->reglist_head, reglist_entry) {
	if (reg->mark)
	nhrp_reg_delete(reg);
	}
	}

	static int nhrp_nhs_resolve(struct thread *t)
	{
	struct nhrp_nhs *nhs = THREAD_ARG(t);

	resolver_resolve(&nhs->dns_resolve, AF_INET, nhs->nbma_fqdn, nhrp_nhs_resolve_cb);

	return 0;
	}

	int nhrp_nhs_add(struct interface ifp, afi_t afi, union sockunion proto_addr, const char *nbma_fqdn)
	{
	struct nhrp_interface *nifp = ifp->info;
	struct nhrp_nhs *nhs;

	if (sockunion_family(proto_addr) != AF_UNSPEC &&
	sockunion_family(proto_addr) != afi2family(afi))
	return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;

	list_for_each_entry(nhs, &nifp->afi[afi].nhslist_head, nhslist_entry) {
	if (sockunion_family(&nhs->proto_addr) != AF_UNSPEC &&
	sockunion_family(proto_addr) != AF_UNSPEC &&
	sockunion_same(&nhs->proto_addr, proto_addr))
	return NHRP_ERR_ENTRY_EXISTS;

	if (strcmp(nhs->nbma_fqdn, nbma_fqdn) == 0)
	return NHRP_ERR_ENTRY_EXISTS;
	}

	nhs = XMALLOC(MTYPE_NHRP_NHS, sizeof(struct nhrp_nhs));
	if (!nhs) return NHRP_ERR_NO_MEMORY;

	*nhs = (struct nhrp_nhs) {
	.afi = afi,
	.ifp = ifp,
	.proto_addr = *proto_addr,
	.nbma_fqdn = strdup(nbma_fqdn),
	.reglist_head = LIST_INITIALIZER(nhs->reglist_head),
	};
	list_add_tail(&nhs->nhslist_entry, &nifp->afi[afi].nhslist_head);
	THREAD_TIMER_MSEC_ON(master, nhs->t_resolve, nhrp_nhs_resolve, nhs, 1000);

	return NHRP_OK;
	}

	int nhrp_nhs_del(struct interface ifp, afi_t afi, union sockunion proto_addr, const char *nbma_fqdn)
	{
	struct nhrp_interface *nifp = ifp->info;
	struct nhrp_nhs nhs, nnhs;
	int ret = NHRP_ERR_ENTRY_NOT_FOUND;

	if (sockunion_family(proto_addr) != AF_UNSPEC &&
	sockunion_family(proto_addr) != afi2family(afi))
	return NHRP_ERR_PROTOCOL_ADDRESS_MISMATCH;

	list_for_each_entry_safe(nhs, nnhs, &nifp->afi[afi].nhslist_head, nhslist_entry) {
	if (!sockunion_same(&nhs->proto_addr, proto_addr))
	continue;
	if (strcmp(nhs->nbma_fqdn, nbma_fqdn) != 0)
	continue;

	nhrp_nhs_free(nhs);
	ret = NHRP_OK;
	}

	return ret;
	}

	int nhrp_nhs_free(struct nhrp_nhs *nhs)
	{
	struct nhrp_registration r, rn;

	list_for_each_entry_safe(r, rn, &nhs->reglist_head, reglist_entry)
	nhrp_reg_delete(r);
	THREAD_OFF(nhs->t_resolve);
	list_del(&nhs->nhslist_entry);
	free((void*) nhs->nbma_fqdn);
	XFREE(MTYPE_NHRP_NHS, nhs);
	return 0;
	}

	void nhrp_nhs_terminate(void)
	{
	struct interface *ifp;
	struct nhrp_interface *nifp;
	struct nhrp_nhs nhs, tmp;
	struct listnode *node;
	afi_t afi;

	for (ALL_LIST_ELEMENTS_RO(iflist, node, ifp)) {
	nifp = ifp->info;
	for (afi = 0; afi < AFI_MAX; afi++) {
	list_for_each_entry_safe(nhs, tmp, &nifp->afi[afi].nhslist_head, nhslist_entry)
	nhrp_nhs_free(nhs);
	}
	}
	}