[mirror_frr.git] / nhrpd / nhrp_shortcut.c

/* NHRP shortcut related functions
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "nhrpd.h"
#include "table.h"
#include "memory.h"
#include "thread.h"
#include "log.h"
#include "nhrp_protocol.h"

DEFINE_MTYPE_STATIC(NHRPD, NHRP_SHORTCUT, "NHRP shortcut")

static struct route_table *shortcut_rib[AFI_MAX];

static int nhrp_shortcut_do_purge(struct thread *t);
static void nhrp_shortcut_delete(struct nhrp_shortcut *s);
static void nhrp_shortcut_send_resolution_req(struct nhrp_shortcut *s);

static void nhrp_shortcut_check_use(struct nhrp_shortcut *s)
{
	char buf[PREFIX_STRLEN];

	if (s->expiring && s->cache && s->cache->used) {
		debugf(NHRP_DEBUG_ROUTE, "Shortcut %s used and expiring",
		       prefix2str(s->p, buf, sizeof(buf)));
		nhrp_shortcut_send_resolution_req(s);
	}
}

static int nhrp_shortcut_do_expire(struct thread *t)
{
	struct nhrp_shortcut *s = THREAD_ARG(t);

	s->t_timer = NULL;
	thread_add_timer(master, nhrp_shortcut_do_purge, s, s->holding_time / 3,
			 &s->t_timer);
	s->expiring = 1;
	nhrp_shortcut_check_use(s);

	return 0;
}

static void nhrp_shortcut_cache_notify(struct notifier_block *n,
				       unsigned long cmd)
{
	char buf[PREFIX_STRLEN];

	struct nhrp_shortcut *s =
		container_of(n, struct nhrp_shortcut, cache_notifier);

	switch (cmd) {
	case NOTIFY_CACHE_UP:
		if (!s->route_installed) {
			debugf(NHRP_DEBUG_ROUTE,
			       "Shortcut: route install %s nh (unspec) dev %s",
			       prefix2str(s->p, buf, sizeof(buf)),
			       s->cache->ifp->name);

			nhrp_route_announce(1, s->type, s->p, s->cache->ifp,
					    NULL, 0);
			s->route_installed = 1;
		}
		break;
	case NOTIFY_CACHE_USED:
		nhrp_shortcut_check_use(s);
		break;
	case NOTIFY_CACHE_DOWN:
	case NOTIFY_CACHE_DELETE:
		if (s->route_installed) {
			nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL,
					    NULL, 0);
			s->route_installed = 0;
		}
		if (cmd == NOTIFY_CACHE_DELETE)
			nhrp_shortcut_delete(s);
		break;
	}
}

static void nhrp_shortcut_update_binding(struct nhrp_shortcut *s,
					 enum nhrp_cache_type type,
					 struct nhrp_cache *c, int holding_time)
{
	char buf[2][PREFIX_STRLEN];

	s->type = type;
	if (c != s->cache) {
		if (s->cache) {
			nhrp_cache_notify_del(s->cache, &s->cache_notifier);
			s->cache = NULL;
		}
		s->cache = c;
		if (s->cache) {
			nhrp_cache_notify_add(s->cache, &s->cache_notifier,
					      nhrp_shortcut_cache_notify);
			if (s->cache->route_installed) {
				/* Force renewal of Zebra announce on prefix
				 * change */
				s->route_installed = 0;
				debugf(NHRP_DEBUG_ROUTE,
				       "Shortcut: forcing renewal of zebra announce on prefix change peer %s ht %u cur nbma %s dev %s",
				       sockunion2str(&s->cache->remote_addr,
						     buf[0], sizeof(buf[0])),
				       holding_time,
				       sockunion2str(
					       &s->cache->cur.remote_nbma_natoa,
					       buf[1], sizeof(buf[1])),
				       s->cache->ifp->name);
				nhrp_shortcut_cache_notify(&s->cache_notifier,
							   NOTIFY_CACHE_UP);
			}
		}
		if (!s->cache || !s->cache->route_installed) {
			debugf(NHRP_DEBUG_ROUTE,
			       "Shortcut: notify cache down because cache?%s or ri?%s",
			       s->cache ? "yes" : "no",
			       s->cache ? (s->cache->route_installed ? "yes"
								     : "no")
					: "n/a");
			nhrp_shortcut_cache_notify(&s->cache_notifier,
						   NOTIFY_CACHE_DOWN);
		}
	}
	if (s->type == NHRP_CACHE_NEGATIVE && !s->route_installed) {
		nhrp_route_announce(1, s->type, s->p, NULL, NULL, 0);
		s->route_installed = 1;
	} else if (s->type == NHRP_CACHE_INVALID && s->route_installed) {
		nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL, NULL, 0);
		s->route_installed = 0;
	}

	THREAD_OFF(s->t_timer);
	if (holding_time) {
		s->expiring = 0;
		s->holding_time = holding_time;
		thread_add_timer(master, nhrp_shortcut_do_expire, s,
				 2 * holding_time / 3, &s->t_timer);
	}
}

static void nhrp_shortcut_delete(struct nhrp_shortcut *s)
{
	struct route_node *rn;
	afi_t afi = family2afi(PREFIX_FAMILY(s->p));
	char buf[PREFIX_STRLEN];

	THREAD_OFF(s->t_timer);
	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);

	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s purged",
	       prefix2str(s->p, buf, sizeof(buf)));

	nhrp_shortcut_update_binding(s, NHRP_CACHE_INVALID, NULL, 0);

	/* Delete node */
	rn = route_node_lookup(shortcut_rib[afi], s->p);
	if (rn) {
		XFREE(MTYPE_NHRP_SHORTCUT, rn->info);
		rn->info = NULL;
		route_unlock_node(rn);
		route_unlock_node(rn);
	}
}

static int nhrp_shortcut_do_purge(struct thread *t)
{
	struct nhrp_shortcut *s = THREAD_ARG(t);
	s->t_timer = NULL;
	nhrp_shortcut_delete(s);
	return 0;
}

static struct nhrp_shortcut *nhrp_shortcut_get(struct prefix *p)
{
	struct nhrp_shortcut *s;
	struct route_node *rn;
	char buf[PREFIX_STRLEN];
	afi_t afi = family2afi(PREFIX_FAMILY(p));

	if (!shortcut_rib[afi])
		return 0;

	rn = route_node_get(shortcut_rib[afi], p);
	if (!rn->info) {
		s = rn->info = XCALLOC(MTYPE_NHRP_SHORTCUT,
				       sizeof(struct nhrp_shortcut));
		s->type = NHRP_CACHE_INVALID;
		s->p = &rn->p;

		debugf(NHRP_DEBUG_ROUTE, "Shortcut %s created",
		       prefix2str(s->p, buf, sizeof(buf)));
	} else {
		s = rn->info;
		route_unlock_node(rn);
	}
	return s;
}

static void nhrp_shortcut_recv_resolution_rep(struct nhrp_reqid *reqid,
					      void *arg)
{
	struct nhrp_packet_parser *pp = arg;
	struct nhrp_shortcut *s =
		container_of(reqid, struct nhrp_shortcut, reqid);
	struct nhrp_shortcut *ps;
	struct nhrp_extension_header *ext;
	struct nhrp_cie_header *cie;
	struct nhrp_cache *c = NULL;
	union sockunion *proto, cie_proto, *nbma, cie_nbma, nat_nbma;
	struct prefix prefix, route_prefix;
	struct zbuf extpl;
	char bufp[PREFIX_STRLEN], buf[4][SU_ADDRSTRLEN];
	int holding_time = pp->if_ad->holdtime;

	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	THREAD_OFF(s->t_timer);
	thread_add_timer(master, nhrp_shortcut_do_purge, s, 1, &s->t_timer);

	if (pp->hdr->type != NHRP_PACKET_RESOLUTION_REPLY) {
		if (pp->hdr->type == NHRP_PACKET_ERROR_INDICATION
		    && pp->hdr->u.error.code
			       == NHRP_ERROR_PROTOCOL_ADDRESS_UNREACHABLE) {
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: Resolution: Protocol address unreachable");
			nhrp_shortcut_update_binding(s, NHRP_CACHE_NEGATIVE,
						     NULL, holding_time);
		} else {
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: Resolution failed");
		}
		return;
	}

	/* Parse extensions */
	memset(&nat_nbma, 0, sizeof(nat_nbma));
	while ((ext = nhrp_ext_pull(&pp->extensions, &extpl)) != NULL) {
		switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
		case NHRP_EXTENSION_NAT_ADDRESS:
			nhrp_cie_pull(&extpl, pp->hdr, &nat_nbma, &cie_proto);
			break;
		}
	}

	/* Minor sanity check */
	prefix2sockunion(s->p, &cie_proto);
	if (!sockunion_same(&cie_proto, &pp->dst_proto)) {
		debugf(NHRP_DEBUG_COMMON,
		       "Shortcut: Warning dst_proto altered from %s to %s",
		       sockunion2str(&cie_proto, buf[0], sizeof(buf[0])),
		       sockunion2str(&pp->dst_proto, buf[1], sizeof(buf[1])));
	}

	/* One or more CIEs should be given as reply, we support only one */
	cie = nhrp_cie_pull(&pp->payload, pp->hdr, &cie_nbma, &cie_proto);
	if (!cie || cie->code != NHRP_CODE_SUCCESS) {
		debugf(NHRP_DEBUG_COMMON, "Shortcut: CIE code %d",
		       cie ? cie->code : -1);
		return;
	}

	proto = sockunion_family(&cie_proto) != AF_UNSPEC ? &cie_proto
							  : &pp->dst_proto;
	if (cie->holding_time)
		holding_time = htons(cie->holding_time);

	prefix = *s->p;
	prefix.prefixlen = cie->prefix_length;

	/* Sanity check prefix length */
	if (prefix.prefixlen >= 8 * prefix_blen(&prefix)
	    || prefix.prefixlen == 0) {
		prefix.prefixlen = 8 * prefix_blen(&prefix);
	} else if (nhrp_route_address(NULL, &pp->dst_proto, &route_prefix, NULL)
		   == NHRP_ROUTE_NBMA_NEXTHOP) {
		if (prefix.prefixlen < route_prefix.prefixlen)
			prefix.prefixlen = route_prefix.prefixlen;
	}

	debugf(NHRP_DEBUG_COMMON,
	       "Shortcut: %s is at proto %s dst_proto %s cie-nbma %s nat-nbma %s cie-holdtime %d",
	       prefix2str(&prefix, bufp, sizeof(bufp)),
	       sockunion2str(proto, buf[0], sizeof(buf[0])),
	       sockunion2str(&pp->dst_proto, buf[1], sizeof(buf[1])),
	       sockunion2str(&cie_nbma, buf[2], sizeof(buf[2])),
	       sockunion2str(&nat_nbma, buf[3], sizeof(buf[3])),
	       htons(cie->holding_time));

	/* Update cache entry for the protocol to nbma binding */
	if (sockunion_family(&nat_nbma) != AF_UNSPEC)
		nbma = &nat_nbma;
	else
		nbma = &cie_nbma;

	if (sockunion_family(nbma)) {
		c = nhrp_cache_get(pp->ifp, proto, 1);
		if (c) {
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: cache found, update binding");
			nhrp_cache_update_binding(c, NHRP_CACHE_DYNAMIC,
						  holding_time,
						  nhrp_peer_get(pp->ifp, nbma),
						  htons(cie->mtu), nbma);
		} else {
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: no cache for nbma %s", buf[2]);
		}
	}

	/* Update shortcut entry for subnet to protocol gw binding */
	if (c) {
		ps = nhrp_shortcut_get(&prefix);
		if (ps) {
			ps->addr = s->addr;
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: calling update_binding");
			nhrp_shortcut_update_binding(ps, NHRP_CACHE_DYNAMIC, c,
						     holding_time);
		} else {
			debugf(NHRP_DEBUG_COMMON,
			       "Shortcut: proto diff but no ps");
		}
	} else {
		debugf(NHRP_DEBUG_COMMON,
		       "NO Shortcut because c NULL?%s or same proto?%s",
		       c ? "no" : "yes",
		       proto && pp && sockunion_same(proto, &pp->dst_proto)
			       ? "yes"
			       : "no");
	}

	debugf(NHRP_DEBUG_COMMON, "Shortcut: Resolution reply handled");
}

static void nhrp_shortcut_send_resolution_req(struct nhrp_shortcut *s)
{
	struct zbuf *zb;
	struct nhrp_packet_header *hdr;
	struct interface *ifp;
	struct nhrp_interface *nifp;
	struct nhrp_afi_data *if_ad;
	struct nhrp_peer *peer;
	struct nhrp_cie_header *cie;

	if (nhrp_route_address(NULL, &s->addr, NULL, &peer)
	    != NHRP_ROUTE_NBMA_NEXTHOP)
		return;

	if (s->type == NHRP_CACHE_INVALID || s->type == NHRP_CACHE_NEGATIVE)
		s->type = NHRP_CACHE_INCOMPLETE;

	ifp = peer->ifp;
	nifp = ifp->info;

	/* Create request */
	zb = zbuf_alloc(1500);
	hdr = nhrp_packet_push(
		zb, NHRP_PACKET_RESOLUTION_REQUEST, &nifp->nbma,
		&nifp->afi[family2afi(sockunion_family(&s->addr))].addr,
		&s->addr);
	hdr->u.request_id =
		htonl(nhrp_reqid_alloc(&nhrp_packet_reqid, &s->reqid,
				       nhrp_shortcut_recv_resolution_rep));
	hdr->flags = htons(NHRP_FLAG_RESOLUTION_SOURCE_IS_ROUTER
			   | NHRP_FLAG_RESOLUTION_AUTHORATIVE
			   | NHRP_FLAG_RESOLUTION_SOURCE_STABLE);

	/* RFC2332 - One or zero CIEs, if CIE is present contains:
	 *  - Prefix length: widest acceptable prefix we accept (if U set, 0xff)
	 *  - MTU: MTU of the source station
	 *  - Holding Time: Max time to cache the source information
	 * */
	/* FIXME: push CIE for each local protocol address */
	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, NULL, NULL);
	cie->prefix_length = 0xff;
	if_ad = &nifp->afi[family2afi(sockunion_family(&s->addr))];
	cie->holding_time = htons(if_ad->holdtime);
	cie->mtu = htons(if_ad->mtu);
	debugf(NHRP_DEBUG_COMMON,
	       "Shortcut res_req: set cie ht to %u and mtu to %u. shortcut ht is %u",
	       ntohs(cie->holding_time), ntohs(cie->mtu), s->holding_time);

	nhrp_ext_request(zb, hdr, ifp);

	/* Cisco NAT detection extension */
	hdr->flags |= htons(NHRP_FLAG_RESOLUTION_NAT);
	nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);

	nhrp_packet_complete(zb, hdr);

	nhrp_peer_send(peer, zb);
	nhrp_peer_unref(peer);
	zbuf_free(zb);
}

void nhrp_shortcut_initiate(union sockunion *addr)
{
	struct prefix p;
	struct nhrp_shortcut *s;

	sockunion2hostprefix(addr, &p);
	s = nhrp_shortcut_get(&p);
	if (s && s->type != NHRP_CACHE_INCOMPLETE) {
		s->addr = *addr;
		THREAD_OFF(s->t_timer);
		thread_add_timer(master, nhrp_shortcut_do_purge, s, 30,
				 &s->t_timer);
		nhrp_shortcut_send_resolution_req(s);
	}
}

void nhrp_shortcut_init(void)
{
	shortcut_rib[AFI_IP] = route_table_init();
	shortcut_rib[AFI_IP6] = route_table_init();
}

void nhrp_shortcut_terminate(void)
{
	route_table_finish(shortcut_rib[AFI_IP]);
	route_table_finish(shortcut_rib[AFI_IP6]);
}

void nhrp_shortcut_foreach(afi_t afi,
			   void (*cb)(struct nhrp_shortcut *, void *),
			   void *ctx)
{
	struct route_table *rt = shortcut_rib[afi];
	struct route_node *rn;
	route_table_iter_t iter;

	if (!rt)
		return;

	route_table_iter_init(&iter, rt);
	while ((rn = route_table_iter_next(&iter)) != NULL) {
		if (rn->info)
			cb(rn->info, ctx);
	}
	route_table_iter_cleanup(&iter);
}

struct purge_ctx {
	const struct prefix *p;
	int deleted;
};

void nhrp_shortcut_purge(struct nhrp_shortcut *s, int force)
{
	THREAD_OFF(s->t_timer);
	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);

	if (force) {
		/* Immediate purge on route with draw or pending shortcut */
		thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 5,
				      &s->t_timer);
	} else {
		/* Soft expire - force immediate renewal, but purge
		 * in few seconds to make sure stale route is not
		 * used too long. In practice most purges are caused
		 * by hub bgp change, but target usually stays same.
		 * This allows to keep nhrp route up, and to not
		 * cause temporary rerouting via hubs causing latency
		 * jitter. */
		thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 3000,
				      &s->t_timer);
		s->expiring = 1;
		nhrp_shortcut_check_use(s);
	}
}

static void nhrp_shortcut_purge_prefix(struct nhrp_shortcut *s, void *ctx)
{
	struct purge_ctx *pctx = ctx;

	if (prefix_match(pctx->p, s->p))
		nhrp_shortcut_purge(s, pctx->deleted || !s->cache);
}

void nhrp_shortcut_prefix_change(const struct prefix *p, int deleted)
{
	struct purge_ctx pctx = {
		.p = p, .deleted = deleted,
	};
	nhrp_shortcut_foreach(family2afi(PREFIX_FAMILY(p)),
			      nhrp_shortcut_purge_prefix, &pctx);
}
Commit	Line	Data
2fb975da TT	1	/* NHRP shortcut related functions
	2	* Copyright (c) 2014-2015 Timo Teräs
	3	*
	4	* This file is free software: you may copy, redistribute and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation, either version 2 of the License, or
	7	* (at your option) any later version.
	8	*/
	9
b45ac5f5 DL	10	#ifdef HAVE_CONFIG_H
	11	#include "config.h"
	12	#endif
	13
2fb975da TT	14	#include "nhrpd.h"
	15	#include "table.h"
	16	#include "memory.h"
	17	#include "thread.h"
	18	#include "log.h"
	19	#include "nhrp_protocol.h"
	20
819dc8bb DL	21	DEFINE_MTYPE_STATIC(NHRPD, NHRP_SHORTCUT, "NHRP shortcut")
819dc8bb DL	22
2fb975da TT	23	static struct route_table *shortcut_rib[AFI_MAX];
	24
	25	static int nhrp_shortcut_do_purge(struct thread *t);
	26	static void nhrp_shortcut_delete(struct nhrp_shortcut *s);
	27	static void nhrp_shortcut_send_resolution_req(struct nhrp_shortcut *s);
	28
	29	static void nhrp_shortcut_check_use(struct nhrp_shortcut *s)
	30	{
	31	char buf[PREFIX_STRLEN];
	32
	33	if (s->expiring && s->cache && s->cache->used) {
	34	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s used and expiring",
0d6f7fd6	35	prefix2str(s->p, buf, sizeof(buf)));
2fb975da TT	36	nhrp_shortcut_send_resolution_req(s);
	37	}
	38	}
	39
	40	static int nhrp_shortcut_do_expire(struct thread *t)
	41	{
	42	struct nhrp_shortcut *s = THREAD_ARG(t);
	43
	44	s->t_timer = NULL;
996c9314 LB	45	thread_add_timer(master, nhrp_shortcut_do_purge, s, s->holding_time / 3,
996c9314 LB	46	&s->t_timer);
2fb975da TT	47	s->expiring = 1;
	48	nhrp_shortcut_check_use(s);
	49
	50	return 0;
	51	}
	52
996c9314 LB	53	static void nhrp_shortcut_cache_notify(struct notifier_block *n,
996c9314 LB	54	unsigned long cmd)
2fb975da	55	{
912c556b GN	56	char buf[PREFIX_STRLEN];
912c556b GN	57
996c9314 LB	58	struct nhrp_shortcut *s =
996c9314 LB	59	container_of(n, struct nhrp_shortcut, cache_notifier);
2fb975da TT	60
	61	switch (cmd) {
	62	case NOTIFY_CACHE_UP:
	63	if (!s->route_installed) {
912c556b	64	debugf(NHRP_DEBUG_ROUTE,
5f36c26c	65	"Shortcut: route install %s nh (unspec) dev %s",
912c556b GN	66	prefix2str(s->p, buf, sizeof(buf)),
	67	s->cache->ifp->name);
	68
	69	nhrp_route_announce(1, s->type, s->p, s->cache->ifp,
	70	NULL, 0);
2fb975da TT	71	s->route_installed = 1;
	72	}
	73	break;
	74	case NOTIFY_CACHE_USED:
	75	nhrp_shortcut_check_use(s);
	76	break;
	77	case NOTIFY_CACHE_DOWN:
	78	case NOTIFY_CACHE_DELETE:
	79	if (s->route_installed) {
996c9314 LB	80	nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL,
996c9314 LB	81	NULL, 0);
2fb975da TT	82	s->route_installed = 0;
	83	}
	84	if (cmd == NOTIFY_CACHE_DELETE)
	85	nhrp_shortcut_delete(s);
	86	break;
	87	}
	88	}
	89
996c9314 LB	90	static void nhrp_shortcut_update_binding(struct nhrp_shortcut *s,
	91	enum nhrp_cache_type type,
	92	struct nhrp_cache *c, int holding_time)
2fb975da	93	{
912c556b GN	94	char buf[2][PREFIX_STRLEN];
912c556b GN	95
2fb975da TT	96	s->type = type;
	97	if (c != s->cache) {
	98	if (s->cache) {
	99	nhrp_cache_notify_del(s->cache, &s->cache_notifier);
	100	s->cache = NULL;
	101	}
	102	s->cache = c;
	103	if (s->cache) {
996c9314 LB	104	nhrp_cache_notify_add(s->cache, &s->cache_notifier,
996c9314 LB	105	nhrp_shortcut_cache_notify);
2fb975da	106	if (s->cache->route_installed) {
996c9314 LB	107	/* Force renewal of Zebra announce on prefix
996c9314 LB	108	* change */
2fb975da	109	s->route_installed = 0;
912c556b	110	debugf(NHRP_DEBUG_ROUTE,
5f36c26c	111	"Shortcut: forcing renewal of zebra announce on prefix change peer %s ht %u cur nbma %s dev %s",
912c556b GN	112	sockunion2str(&s->cache->remote_addr,
	113	buf[0], sizeof(buf[0])),
	114	holding_time,
	115	sockunion2str(
	116	&s->cache->cur.remote_nbma_natoa,
	117	buf[1], sizeof(buf[1])),
	118	s->cache->ifp->name);
996c9314 LB	119	nhrp_shortcut_cache_notify(&s->cache_notifier,
996c9314 LB	120	NOTIFY_CACHE_UP);
2fb975da TT	121	}
2fb975da TT	122	}
912c556b GN	123	if (!s->cache \|\| !s->cache->route_installed) {
912c556b GN	124	debugf(NHRP_DEBUG_ROUTE,
5f36c26c	125	"Shortcut: notify cache down because cache?%s or ri?%s",
912c556b GN	126	s->cache ? "yes" : "no",
	127	s->cache ? (s->cache->route_installed ? "yes"
	128	: "no")
	129	: "n/a");
996c9314 LB	130	nhrp_shortcut_cache_notify(&s->cache_notifier,
996c9314 LB	131	NOTIFY_CACHE_DOWN);
912c556b	132	}
2fb975da TT	133	}
	134	if (s->type == NHRP_CACHE_NEGATIVE && !s->route_installed) {
	135	nhrp_route_announce(1, s->type, s->p, NULL, NULL, 0);
	136	s->route_installed = 1;
	137	} else if (s->type == NHRP_CACHE_INVALID && s->route_installed) {
	138	nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL, NULL, 0);
	139	s->route_installed = 0;
	140	}
	141
	142	THREAD_OFF(s->t_timer);
	143	if (holding_time) {
	144	s->expiring = 0;
	145	s->holding_time = holding_time;
ffa2c898 QY	146	thread_add_timer(master, nhrp_shortcut_do_expire, s,
ffa2c898 QY	147	2 * holding_time / 3, &s->t_timer);
2fb975da TT	148	}
	149	}
	150
	151	static void nhrp_shortcut_delete(struct nhrp_shortcut *s)
	152	{
	153	struct route_node *rn;
	154	afi_t afi = family2afi(PREFIX_FAMILY(s->p));
	155	char buf[PREFIX_STRLEN];
	156
	157	THREAD_OFF(s->t_timer);
	158	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	159
	160	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s purged",
0d6f7fd6	161	prefix2str(s->p, buf, sizeof(buf)));
2fb975da TT	162
	163	nhrp_shortcut_update_binding(s, NHRP_CACHE_INVALID, NULL, 0);
	164
	165	/* Delete node */
	166	rn = route_node_lookup(shortcut_rib[afi], s->p);
	167	if (rn) {
	168	XFREE(MTYPE_NHRP_SHORTCUT, rn->info);
912c556b	169	rn->info = NULL;
2fb975da TT	170	route_unlock_node(rn);
	171	route_unlock_node(rn);
	172	}
	173	}
	174
	175	static int nhrp_shortcut_do_purge(struct thread *t)
	176	{
	177	struct nhrp_shortcut *s = THREAD_ARG(t);
	178	s->t_timer = NULL;
	179	nhrp_shortcut_delete(s);
	180	return 0;
	181	}
	182
	183	static struct nhrp_shortcut nhrp_shortcut_get(struct prefix p)
	184	{
	185	struct nhrp_shortcut *s;
	186	struct route_node *rn;
	187	char buf[PREFIX_STRLEN];
	188	afi_t afi = family2afi(PREFIX_FAMILY(p));
	189
	190	if (!shortcut_rib[afi])
	191	return 0;
	192
	193	rn = route_node_get(shortcut_rib[afi], p);
	194	if (!rn->info) {
996c9314 LB	195	s = rn->info = XCALLOC(MTYPE_NHRP_SHORTCUT,
996c9314 LB	196	sizeof(struct nhrp_shortcut));
2fb975da TT	197	s->type = NHRP_CACHE_INVALID;
	198	s->p = &rn->p;
	199
	200	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s created",
0d6f7fd6	201	prefix2str(s->p, buf, sizeof(buf)));
2fb975da TT	202	} else {
	203	s = rn->info;
	204	route_unlock_node(rn);
	205	}
	206	return s;
	207	}
	208
996c9314 LB	209	static void nhrp_shortcut_recv_resolution_rep(struct nhrp_reqid *reqid,
996c9314 LB	210	void *arg)
2fb975da TT	211	{
2fb975da TT	212	struct nhrp_packet_parser *pp = arg;
996c9314 LB	213	struct nhrp_shortcut *s =
996c9314 LB	214	container_of(reqid, struct nhrp_shortcut, reqid);
2fb975da TT	215	struct nhrp_shortcut *ps;
	216	struct nhrp_extension_header *ext;
	217	struct nhrp_cie_header *cie;
	218	struct nhrp_cache *c = NULL;
912c556b	219	union sockunion proto, cie_proto, nbma, cie_nbma, nat_nbma;
2fb975da TT	220	struct prefix prefix, route_prefix;
2fb975da TT	221	struct zbuf extpl;
912c556b	222	char bufp[PREFIX_STRLEN], buf[4][SU_ADDRSTRLEN];
2fb975da TT	223	int holding_time = pp->if_ad->holdtime;
	224
	225	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	226	THREAD_OFF(s->t_timer);
ffa2c898	227	thread_add_timer(master, nhrp_shortcut_do_purge, s, 1, &s->t_timer);
2fb975da TT	228
2fb975da TT	229	if (pp->hdr->type != NHRP_PACKET_RESOLUTION_REPLY) {
996c9314 LB	230	if (pp->hdr->type == NHRP_PACKET_ERROR_INDICATION
	231	&& pp->hdr->u.error.code
	232	== NHRP_ERROR_PROTOCOL_ADDRESS_UNREACHABLE) {
	233	debugf(NHRP_DEBUG_COMMON,
	234	"Shortcut: Resolution: Protocol address unreachable");
	235	nhrp_shortcut_update_binding(s, NHRP_CACHE_NEGATIVE,
	236	NULL, holding_time);
2fb975da	237	} else {
996c9314 LB	238	debugf(NHRP_DEBUG_COMMON,
996c9314 LB	239	"Shortcut: Resolution failed");
2fb975da TT	240	}
	241	return;
	242	}
	243
	244	/* Parse extensions */
0d6f7fd6	245	memset(&nat_nbma, 0, sizeof(nat_nbma));
2fb975da TT	246	while ((ext = nhrp_ext_pull(&pp->extensions, &extpl)) != NULL) {
	247	switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
	248	case NHRP_EXTENSION_NAT_ADDRESS:
	249	nhrp_cie_pull(&extpl, pp->hdr, &nat_nbma, &cie_proto);
	250	break;
	251	}
	252	}
	253
	254	/* Minor sanity check */
	255	prefix2sockunion(s->p, &cie_proto);
	256	if (!sockunion_same(&cie_proto, &pp->dst_proto)) {
996c9314 LB	257	debugf(NHRP_DEBUG_COMMON,
996c9314 LB	258	"Shortcut: Warning dst_proto altered from %s to %s",
0d6f7fd6 DA	259	sockunion2str(&cie_proto, buf[0], sizeof(buf[0])),
0d6f7fd6 DA	260	sockunion2str(&pp->dst_proto, buf[1], sizeof(buf[1])));
2fb975da TT	261	}
	262
	263	/* One or more CIEs should be given as reply, we support only one */
	264	cie = nhrp_cie_pull(&pp->payload, pp->hdr, &cie_nbma, &cie_proto);
	265	if (!cie \|\| cie->code != NHRP_CODE_SUCCESS) {
996c9314 LB	266	debugf(NHRP_DEBUG_COMMON, "Shortcut: CIE code %d",
996c9314 LB	267	cie ? cie->code : -1);
2fb975da TT	268	return;
	269	}
	270
996c9314 LB	271	proto = sockunion_family(&cie_proto) != AF_UNSPEC ? &cie_proto
996c9314 LB	272	: &pp->dst_proto;
2fb975da TT	273	if (cie->holding_time)
	274	holding_time = htons(cie->holding_time);
	275
	276	prefix = *s->p;
	277	prefix.prefixlen = cie->prefix_length;
	278
	279	/* Sanity check prefix length */
996c9314 LB	280	if (prefix.prefixlen >= 8 * prefix_blen(&prefix)
	281	\|\| prefix.prefixlen == 0) {
	282	prefix.prefixlen = 8 * prefix_blen(&prefix);
	283	} else if (nhrp_route_address(NULL, &pp->dst_proto, &route_prefix, NULL)
	284	== NHRP_ROUTE_NBMA_NEXTHOP) {
2fb975da TT	285	if (prefix.prefixlen < route_prefix.prefixlen)
	286	prefix.prefixlen = route_prefix.prefixlen;
	287	}
	288
996c9314	289	debugf(NHRP_DEBUG_COMMON,
31384f92	290	"Shortcut: %s is at proto %s dst_proto %s cie-nbma %s nat-nbma %s cie-holdtime %d",
0d6f7fd6	291	prefix2str(&prefix, bufp, sizeof(bufp)),
912c556b GN	292	sockunion2str(proto, buf[0], sizeof(buf[0])),
	293	sockunion2str(&pp->dst_proto, buf[1], sizeof(buf[1])),
	294	sockunion2str(&cie_nbma, buf[2], sizeof(buf[2])),
	295	sockunion2str(&nat_nbma, buf[3], sizeof(buf[3])),
996c9314	296	htons(cie->holding_time));
2fb975da TT	297
2fb975da TT	298	/* Update cache entry for the protocol to nbma binding */
912c556b	299	if (sockunion_family(&nat_nbma) != AF_UNSPEC)
2fb975da	300	nbma = &nat_nbma;
912c556b	301	else
2fb975da	302	nbma = &cie_nbma;
912c556b	303
2fb975da TT	304	if (sockunion_family(nbma)) {
	305	c = nhrp_cache_get(pp->ifp, proto, 1);
	306	if (c) {
912c556b GN	307	debugf(NHRP_DEBUG_COMMON,
	308	"Shortcut: cache found, update binding");
	309	nhrp_cache_update_binding(c, NHRP_CACHE_DYNAMIC,
996c9314 LB	310	holding_time,
996c9314 LB	311	nhrp_peer_get(pp->ifp, nbma),
912c556b GN	312	htons(cie->mtu), nbma);
	313	} else {
	314	debugf(NHRP_DEBUG_COMMON,
	315	"Shortcut: no cache for nbma %s", buf[2]);
2fb975da TT	316	}
	317	}
	318
	319	/* Update shortcut entry for subnet to protocol gw binding */
912c556b	320	if (c) {
2fb975da TT	321	ps = nhrp_shortcut_get(&prefix);
	322	if (ps) {
	323	ps->addr = s->addr;
912c556b	324	debugf(NHRP_DEBUG_COMMON,
5f36c26c	325	"Shortcut: calling update_binding");
912c556b	326	nhrp_shortcut_update_binding(ps, NHRP_CACHE_DYNAMIC, c,
996c9314	327	holding_time);
912c556b GN	328	} else {
	329	debugf(NHRP_DEBUG_COMMON,
	330	"Shortcut: proto diff but no ps");
2fb975da	331	}
912c556b GN	332	} else {
912c556b GN	333	debugf(NHRP_DEBUG_COMMON,
5f36c26c	334	"NO Shortcut because c NULL?%s or same proto?%s",
912c556b GN	335	c ? "no" : "yes",
	336	proto && pp && sockunion_same(proto, &pp->dst_proto)
	337	? "yes"
	338	: "no");
2fb975da TT	339	}
	340
	341	debugf(NHRP_DEBUG_COMMON, "Shortcut: Resolution reply handled");
	342	}
	343
	344	static void nhrp_shortcut_send_resolution_req(struct nhrp_shortcut *s)
	345	{
	346	struct zbuf *zb;
	347	struct nhrp_packet_header *hdr;
	348	struct interface *ifp;
	349	struct nhrp_interface *nifp;
47d40757	350	struct nhrp_afi_data *if_ad;
2fb975da	351	struct nhrp_peer *peer;
47d40757	352	struct nhrp_cie_header *cie;
2fb975da	353
996c9314 LB	354	if (nhrp_route_address(NULL, &s->addr, NULL, &peer)
996c9314 LB	355	!= NHRP_ROUTE_NBMA_NEXTHOP)
2fb975da TT	356	return;
	357
	358	if (s->type == NHRP_CACHE_INVALID \|\| s->type == NHRP_CACHE_NEGATIVE)
	359	s->type = NHRP_CACHE_INCOMPLETE;
	360
	361	ifp = peer->ifp;
	362	nifp = ifp->info;
	363
	364	/* Create request */
	365	zb = zbuf_alloc(1500);
996c9314 LB	366	hdr = nhrp_packet_push(
	367	zb, NHRP_PACKET_RESOLUTION_REQUEST, &nifp->nbma,
	368	&nifp->afi[family2afi(sockunion_family(&s->addr))].addr,
	369	&s->addr);
	370	hdr->u.request_id =
	371	htonl(nhrp_reqid_alloc(&nhrp_packet_reqid, &s->reqid,
	372	nhrp_shortcut_recv_resolution_rep));
	373	hdr->flags = htons(NHRP_FLAG_RESOLUTION_SOURCE_IS_ROUTER
	374	\| NHRP_FLAG_RESOLUTION_AUTHORATIVE
	375	\| NHRP_FLAG_RESOLUTION_SOURCE_STABLE);
2fb975da TT	376
	377	/* RFC2332 - One or zero CIEs, if CIE is present contains:
	378	* - Prefix length: widest acceptable prefix we accept (if U set, 0xff)
	379	* - MTU: MTU of the source station
	380	* - Holding Time: Max time to cache the source information
	381	* */
47d40757 GN	382	/* FIXME: push CIE for each local protocol address */
	383	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, NULL, NULL);
	384	cie->prefix_length = 0xff;
	385	if_ad = &nifp->afi[family2afi(sockunion_family(&s->addr))];
	386	cie->holding_time = htons(if_ad->holdtime);
	387	cie->mtu = htons(if_ad->mtu);
	388	debugf(NHRP_DEBUG_COMMON,
5f36c26c	389	"Shortcut res_req: set cie ht to %u and mtu to %u. shortcut ht is %u",
47d40757	390	ntohs(cie->holding_time), ntohs(cie->mtu), s->holding_time);
2fb975da TT	391
	392	nhrp_ext_request(zb, hdr, ifp);
	393
	394	/* Cisco NAT detection extension */
	395	hdr->flags \|= htons(NHRP_FLAG_RESOLUTION_NAT);
	396	nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
	397
	398	nhrp_packet_complete(zb, hdr);
	399
	400	nhrp_peer_send(peer, zb);
	401	nhrp_peer_unref(peer);
	402	zbuf_free(zb);
	403	}
	404
	405	void nhrp_shortcut_initiate(union sockunion *addr)
	406	{
	407	struct prefix p;
	408	struct nhrp_shortcut *s;
	409
	410	sockunion2hostprefix(addr, &p);
	411	s = nhrp_shortcut_get(&p);
	412	if (s && s->type != NHRP_CACHE_INCOMPLETE) {
	413	s->addr = *addr;
	414	THREAD_OFF(s->t_timer);
ffa2c898 QY	415	thread_add_timer(master, nhrp_shortcut_do_purge, s, 30,
ffa2c898 QY	416	&s->t_timer);
2fb975da TT	417	nhrp_shortcut_send_resolution_req(s);
	418	}
	419	}
	420
	421	void nhrp_shortcut_init(void)
	422	{
	423	shortcut_rib[AFI_IP] = route_table_init();
	424	shortcut_rib[AFI_IP6] = route_table_init();
	425	}
	426
	427	void nhrp_shortcut_terminate(void)
	428	{
	429	route_table_finish(shortcut_rib[AFI_IP]);
	430	route_table_finish(shortcut_rib[AFI_IP6]);
	431	}
	432
996c9314 LB	433	void nhrp_shortcut_foreach(afi_t afi,
	434	void (cb)(struct nhrp_shortcut , void *),
	435	void *ctx)
2fb975da TT	436	{
	437	struct route_table *rt = shortcut_rib[afi];
	438	struct route_node *rn;
	439	route_table_iter_t iter;
	440
996c9314 LB	441	if (!rt)
996c9314 LB	442	return;
2fb975da TT	443
	444	route_table_iter_init(&iter, rt);
	445	while ((rn = route_table_iter_next(&iter)) != NULL) {
996c9314 LB	446	if (rn->info)
996c9314 LB	447	cb(rn->info, ctx);
2fb975da TT	448	}
	449	route_table_iter_cleanup(&iter);
	450	}
	451
	452	struct purge_ctx {
	453	const struct prefix *p;
	454	int deleted;
	455	};
	456
	457	void nhrp_shortcut_purge(struct nhrp_shortcut *s, int force)
	458	{
	459	THREAD_OFF(s->t_timer);
	460	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	461
	462	if (force) {
	463	/* Immediate purge on route with draw or pending shortcut */
ffa2c898 QY	464	thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 5,
ffa2c898 QY	465	&s->t_timer);
2fb975da TT	466	} else {
	467	/* Soft expire - force immediate renewal, but purge
	468	* in few seconds to make sure stale route is not
	469	* used too long. In practice most purges are caused
	470	* by hub bgp change, but target usually stays same.
	471	* This allows to keep nhrp route up, and to not
	472	* cause temporary rerouting via hubs causing latency
	473	* jitter. */
ffa2c898 QY	474	thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 3000,
ffa2c898 QY	475	&s->t_timer);
2fb975da TT	476	s->expiring = 1;
	477	nhrp_shortcut_check_use(s);
	478	}
	479	}
	480
	481	static void nhrp_shortcut_purge_prefix(struct nhrp_shortcut s, void ctx)
	482	{
	483	struct purge_ctx *pctx = ctx;
	484
	485	if (prefix_match(pctx->p, s->p))
	486	nhrp_shortcut_purge(s, pctx->deleted \|\| !s->cache);
	487	}
	488
	489	void nhrp_shortcut_prefix_change(const struct prefix *p, int deleted)
	490	{
	491	struct purge_ctx pctx = {
996c9314	492	.p = p, .deleted = deleted,
2fb975da	493	};
996c9314 LB	494	nhrp_shortcut_foreach(family2afi(PREFIX_FAMILY(p)),
996c9314 LB	495	nhrp_shortcut_purge_prefix, &pctx);
2fb975da	496	}