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

	switch (cmd) {
	case NOTIFY_CACHE_UP:
		if (!s->route_installed) {
			nhrp_route_announce(1, s->type, s->p, NULL,
					    &s->cache->remote_addr, 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)
{
	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;
				nhrp_shortcut_cache_notify(&s->cache_notifier,
							   NOTIFY_CACHE_UP);
			}
		}
		if (!s->cache || !s->cache->route_installed)
			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, *nbma_natoa, cie_nbma,
		nat_nbma;
	struct prefix prefix, route_prefix;
	struct zbuf extpl;
	char bufp[PREFIX_STRLEN], buf[3][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 cie-nbma %s nat-nbma %s cie-holdtime %d",
	       prefix2str(&prefix, bufp, sizeof bufp),
	       sockunion2str(proto, buf[0], sizeof buf[0]),
	       sockunion2str(&cie_nbma, buf[1], sizeof buf[1]),
	       sockunion2str(&nat_nbma, buf[2], sizeof buf[2]),
	       htons(cie->holding_time));

	/* Update cache entry for the protocol to nbma binding */
	if (sockunion_family(&nat_nbma) != AF_UNSPEC) {
		nbma = &nat_nbma;
		nbma_natoa = &cie_nbma;
	} else {
		nbma = &cie_nbma;
		nbma_natoa = NULL;
	}
	if (sockunion_family(nbma)) {
		c = nhrp_cache_get(pp->ifp, proto, 1);
		if (c) {
			nhrp_cache_update_binding(c, NHRP_CACHE_CACHED,
						  holding_time,
						  nhrp_peer_get(pp->ifp, nbma),
						  htons(cie->mtu), nbma_natoa);
		}
	}

	/* Update shortcut entry for subnet to protocol gw binding */
	if (c && !sockunion_same(proto, &pp->dst_proto)) {
		ps = nhrp_shortcut_get(&prefix);
		if (ps) {
			ps->addr = s->addr;
			nhrp_shortcut_update_binding(ps, NHRP_CACHE_CACHED, c,
						     holding_time);
		}
	}

	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_peer *peer;

	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: Send holding time, and MTU */

	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",
996c9314	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	{
996c9314 LB	56	struct nhrp_shortcut *s =
996c9314 LB	57	container_of(n, struct nhrp_shortcut, cache_notifier);
2fb975da TT	58
	59	switch (cmd) {
	60	case NOTIFY_CACHE_UP:
	61	if (!s->route_installed) {
996c9314 LB	62	nhrp_route_announce(1, s->type, s->p, NULL,
996c9314 LB	63	&s->cache->remote_addr, 0);
2fb975da TT	64	s->route_installed = 1;
	65	}
	66	break;
	67	case NOTIFY_CACHE_USED:
	68	nhrp_shortcut_check_use(s);
	69	break;
	70	case NOTIFY_CACHE_DOWN:
	71	case NOTIFY_CACHE_DELETE:
	72	if (s->route_installed) {
996c9314 LB	73	nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL,
996c9314 LB	74	NULL, 0);
2fb975da TT	75	s->route_installed = 0;
	76	}
	77	if (cmd == NOTIFY_CACHE_DELETE)
	78	nhrp_shortcut_delete(s);
	79	break;
	80	}
	81	}
	82
996c9314 LB	83	static void nhrp_shortcut_update_binding(struct nhrp_shortcut *s,
	84	enum nhrp_cache_type type,
	85	struct nhrp_cache *c, int holding_time)
2fb975da TT	86	{
	87	s->type = type;
	88	if (c != s->cache) {
	89	if (s->cache) {
	90	nhrp_cache_notify_del(s->cache, &s->cache_notifier);
	91	s->cache = NULL;
	92	}
	93	s->cache = c;
	94	if (s->cache) {
996c9314 LB	95	nhrp_cache_notify_add(s->cache, &s->cache_notifier,
996c9314 LB	96	nhrp_shortcut_cache_notify);
2fb975da	97	if (s->cache->route_installed) {
996c9314 LB	98	/* Force renewal of Zebra announce on prefix
996c9314 LB	99	* change */
2fb975da	100	s->route_installed = 0;
996c9314 LB	101	nhrp_shortcut_cache_notify(&s->cache_notifier,
996c9314 LB	102	NOTIFY_CACHE_UP);
2fb975da TT	103	}
	104	}
	105	if (!s->cache \|\| !s->cache->route_installed)
996c9314 LB	106	nhrp_shortcut_cache_notify(&s->cache_notifier,
996c9314 LB	107	NOTIFY_CACHE_DOWN);
2fb975da TT	108	}
	109	if (s->type == NHRP_CACHE_NEGATIVE && !s->route_installed) {
	110	nhrp_route_announce(1, s->type, s->p, NULL, NULL, 0);
	111	s->route_installed = 1;
	112	} else if (s->type == NHRP_CACHE_INVALID && s->route_installed) {
	113	nhrp_route_announce(0, NHRP_CACHE_INVALID, s->p, NULL, NULL, 0);
	114	s->route_installed = 0;
	115	}
	116
	117	THREAD_OFF(s->t_timer);
	118	if (holding_time) {
	119	s->expiring = 0;
	120	s->holding_time = holding_time;
ffa2c898 QY	121	thread_add_timer(master, nhrp_shortcut_do_expire, s,
ffa2c898 QY	122	2 * holding_time / 3, &s->t_timer);
2fb975da TT	123	}
	124	}
	125
	126	static void nhrp_shortcut_delete(struct nhrp_shortcut *s)
	127	{
	128	struct route_node *rn;
	129	afi_t afi = family2afi(PREFIX_FAMILY(s->p));
	130	char buf[PREFIX_STRLEN];
	131
	132	THREAD_OFF(s->t_timer);
	133	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	134
	135	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s purged",
996c9314	136	prefix2str(s->p, buf, sizeof buf));
2fb975da TT	137
	138	nhrp_shortcut_update_binding(s, NHRP_CACHE_INVALID, NULL, 0);
	139
	140	/* Delete node */
	141	rn = route_node_lookup(shortcut_rib[afi], s->p);
	142	if (rn) {
	143	XFREE(MTYPE_NHRP_SHORTCUT, rn->info);
	144	rn->info = NULL;
	145	route_unlock_node(rn);
	146	route_unlock_node(rn);
	147	}
	148	}
	149
	150	static int nhrp_shortcut_do_purge(struct thread *t)
	151	{
	152	struct nhrp_shortcut *s = THREAD_ARG(t);
	153	s->t_timer = NULL;
	154	nhrp_shortcut_delete(s);
	155	return 0;
	156	}
	157
	158	static struct nhrp_shortcut nhrp_shortcut_get(struct prefix p)
	159	{
	160	struct nhrp_shortcut *s;
	161	struct route_node *rn;
	162	char buf[PREFIX_STRLEN];
	163	afi_t afi = family2afi(PREFIX_FAMILY(p));
	164
	165	if (!shortcut_rib[afi])
	166	return 0;
	167
	168	rn = route_node_get(shortcut_rib[afi], p);
	169	if (!rn->info) {
996c9314 LB	170	s = rn->info = XCALLOC(MTYPE_NHRP_SHORTCUT,
996c9314 LB	171	sizeof(struct nhrp_shortcut));
2fb975da TT	172	s->type = NHRP_CACHE_INVALID;
	173	s->p = &rn->p;
	174
	175	debugf(NHRP_DEBUG_ROUTE, "Shortcut %s created",
996c9314	176	prefix2str(s->p, buf, sizeof buf));
2fb975da TT	177	} else {
	178	s = rn->info;
	179	route_unlock_node(rn);
	180	}
	181	return s;
	182	}
	183
996c9314 LB	184	static void nhrp_shortcut_recv_resolution_rep(struct nhrp_reqid *reqid,
996c9314 LB	185	void *arg)
2fb975da TT	186	{
2fb975da TT	187	struct nhrp_packet_parser *pp = arg;
996c9314 LB	188	struct nhrp_shortcut *s =
996c9314 LB	189	container_of(reqid, struct nhrp_shortcut, reqid);
2fb975da TT	190	struct nhrp_shortcut *ps;
	191	struct nhrp_extension_header *ext;
	192	struct nhrp_cie_header *cie;
	193	struct nhrp_cache *c = NULL;
996c9314 LB	194	union sockunion proto, cie_proto, nbma, *nbma_natoa, cie_nbma,
996c9314 LB	195	nat_nbma;
2fb975da TT	196	struct prefix prefix, route_prefix;
	197	struct zbuf extpl;
	198	char bufp[PREFIX_STRLEN], buf[3][SU_ADDRSTRLEN];
	199	int holding_time = pp->if_ad->holdtime;
	200
	201	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	202	THREAD_OFF(s->t_timer);
ffa2c898	203	thread_add_timer(master, nhrp_shortcut_do_purge, s, 1, &s->t_timer);
2fb975da TT	204
2fb975da TT	205	if (pp->hdr->type != NHRP_PACKET_RESOLUTION_REPLY) {
996c9314 LB	206	if (pp->hdr->type == NHRP_PACKET_ERROR_INDICATION
	207	&& pp->hdr->u.error.code
	208	== NHRP_ERROR_PROTOCOL_ADDRESS_UNREACHABLE) {
	209	debugf(NHRP_DEBUG_COMMON,
	210	"Shortcut: Resolution: Protocol address unreachable");
	211	nhrp_shortcut_update_binding(s, NHRP_CACHE_NEGATIVE,
	212	NULL, holding_time);
2fb975da	213	} else {
996c9314 LB	214	debugf(NHRP_DEBUG_COMMON,
996c9314 LB	215	"Shortcut: Resolution failed");
2fb975da TT	216	}
	217	return;
	218	}
	219
	220	/* Parse extensions */
	221	memset(&nat_nbma, 0, sizeof nat_nbma);
	222	while ((ext = nhrp_ext_pull(&pp->extensions, &extpl)) != NULL) {
	223	switch (htons(ext->type) & ~NHRP_EXTENSION_FLAG_COMPULSORY) {
	224	case NHRP_EXTENSION_NAT_ADDRESS:
	225	nhrp_cie_pull(&extpl, pp->hdr, &nat_nbma, &cie_proto);
	226	break;
	227	}
	228	}
	229
	230	/* Minor sanity check */
	231	prefix2sockunion(s->p, &cie_proto);
	232	if (!sockunion_same(&cie_proto, &pp->dst_proto)) {
996c9314 LB	233	debugf(NHRP_DEBUG_COMMON,
	234	"Shortcut: Warning dst_proto altered from %s to %s",
	235	sockunion2str(&cie_proto, buf[0], sizeof buf[0]),
	236	sockunion2str(&pp->dst_proto, buf[1], sizeof buf[1]));
2fb975da TT	237	}
	238
	239	/* One or more CIEs should be given as reply, we support only one */
	240	cie = nhrp_cie_pull(&pp->payload, pp->hdr, &cie_nbma, &cie_proto);
	241	if (!cie \|\| cie->code != NHRP_CODE_SUCCESS) {
996c9314 LB	242	debugf(NHRP_DEBUG_COMMON, "Shortcut: CIE code %d",
996c9314 LB	243	cie ? cie->code : -1);
2fb975da TT	244	return;
	245	}
	246
996c9314 LB	247	proto = sockunion_family(&cie_proto) != AF_UNSPEC ? &cie_proto
996c9314 LB	248	: &pp->dst_proto;
2fb975da TT	249	if (cie->holding_time)
	250	holding_time = htons(cie->holding_time);
	251
	252	prefix = *s->p;
	253	prefix.prefixlen = cie->prefix_length;
	254
	255	/* Sanity check prefix length */
996c9314 LB	256	if (prefix.prefixlen >= 8 * prefix_blen(&prefix)
	257	\|\| prefix.prefixlen == 0) {
	258	prefix.prefixlen = 8 * prefix_blen(&prefix);
	259	} else if (nhrp_route_address(NULL, &pp->dst_proto, &route_prefix, NULL)
	260	== NHRP_ROUTE_NBMA_NEXTHOP) {
2fb975da TT	261	if (prefix.prefixlen < route_prefix.prefixlen)
	262	prefix.prefixlen = route_prefix.prefixlen;
	263	}
	264
996c9314 LB	265	debugf(NHRP_DEBUG_COMMON,
	266	"Shortcut: %s is at proto %s cie-nbma %s nat-nbma %s cie-holdtime %d",
	267	prefix2str(&prefix, bufp, sizeof bufp),
	268	sockunion2str(proto, buf[0], sizeof buf[0]),
	269	sockunion2str(&cie_nbma, buf[1], sizeof buf[1]),
	270	sockunion2str(&nat_nbma, buf[2], sizeof buf[2]),
	271	htons(cie->holding_time));
2fb975da TT	272
	273	/* Update cache entry for the protocol to nbma binding */
	274	if (sockunion_family(&nat_nbma) != AF_UNSPEC) {
	275	nbma = &nat_nbma;
	276	nbma_natoa = &cie_nbma;
	277	} else {
	278	nbma = &cie_nbma;
	279	nbma_natoa = NULL;
	280	}
	281	if (sockunion_family(nbma)) {
	282	c = nhrp_cache_get(pp->ifp, proto, 1);
	283	if (c) {
996c9314 LB	284	nhrp_cache_update_binding(c, NHRP_CACHE_CACHED,
	285	holding_time,
	286	nhrp_peer_get(pp->ifp, nbma),
	287	htons(cie->mtu), nbma_natoa);
2fb975da TT	288	}
	289	}
	290
	291	/* Update shortcut entry for subnet to protocol gw binding */
	292	if (c && !sockunion_same(proto, &pp->dst_proto)) {
	293	ps = nhrp_shortcut_get(&prefix);
	294	if (ps) {
	295	ps->addr = s->addr;
996c9314 LB	296	nhrp_shortcut_update_binding(ps, NHRP_CACHE_CACHED, c,
996c9314 LB	297	holding_time);
2fb975da TT	298	}
	299	}
	300
	301	debugf(NHRP_DEBUG_COMMON, "Shortcut: Resolution reply handled");
	302	}
	303
	304	static void nhrp_shortcut_send_resolution_req(struct nhrp_shortcut *s)
	305	{
	306	struct zbuf *zb;
	307	struct nhrp_packet_header *hdr;
	308	struct interface *ifp;
	309	struct nhrp_interface *nifp;
	310	struct nhrp_peer *peer;
	311
996c9314 LB	312	if (nhrp_route_address(NULL, &s->addr, NULL, &peer)
996c9314 LB	313	!= NHRP_ROUTE_NBMA_NEXTHOP)
2fb975da TT	314	return;
	315
	316	if (s->type == NHRP_CACHE_INVALID \|\| s->type == NHRP_CACHE_NEGATIVE)
	317	s->type = NHRP_CACHE_INCOMPLETE;
	318
	319	ifp = peer->ifp;
	320	nifp = ifp->info;
	321
	322	/* Create request */
	323	zb = zbuf_alloc(1500);
996c9314 LB	324	hdr = nhrp_packet_push(
	325	zb, NHRP_PACKET_RESOLUTION_REQUEST, &nifp->nbma,
	326	&nifp->afi[family2afi(sockunion_family(&s->addr))].addr,
	327	&s->addr);
	328	hdr->u.request_id =
	329	htonl(nhrp_reqid_alloc(&nhrp_packet_reqid, &s->reqid,
	330	nhrp_shortcut_recv_resolution_rep));
	331	hdr->flags = htons(NHRP_FLAG_RESOLUTION_SOURCE_IS_ROUTER
	332	\| NHRP_FLAG_RESOLUTION_AUTHORATIVE
	333	\| NHRP_FLAG_RESOLUTION_SOURCE_STABLE);
2fb975da TT	334
	335	/* RFC2332 - One or zero CIEs, if CIE is present contains:
	336	* - Prefix length: widest acceptable prefix we accept (if U set, 0xff)
	337	* - MTU: MTU of the source station
	338	* - Holding Time: Max time to cache the source information
	339	* */
	340	/* FIXME: Send holding time, and MTU */
	341
	342	nhrp_ext_request(zb, hdr, ifp);
	343
	344	/* Cisco NAT detection extension */
	345	hdr->flags \|= htons(NHRP_FLAG_RESOLUTION_NAT);
	346	nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
	347
	348	nhrp_packet_complete(zb, hdr);
	349
	350	nhrp_peer_send(peer, zb);
	351	nhrp_peer_unref(peer);
	352	zbuf_free(zb);
	353	}
	354
	355	void nhrp_shortcut_initiate(union sockunion *addr)
	356	{
	357	struct prefix p;
	358	struct nhrp_shortcut *s;
	359
	360	sockunion2hostprefix(addr, &p);
	361	s = nhrp_shortcut_get(&p);
	362	if (s && s->type != NHRP_CACHE_INCOMPLETE) {
	363	s->addr = *addr;
	364	THREAD_OFF(s->t_timer);
ffa2c898 QY	365	thread_add_timer(master, nhrp_shortcut_do_purge, s, 30,
ffa2c898 QY	366	&s->t_timer);
2fb975da TT	367	nhrp_shortcut_send_resolution_req(s);
	368	}
	369	}
	370
	371	void nhrp_shortcut_init(void)
	372	{
	373	shortcut_rib[AFI_IP] = route_table_init();
	374	shortcut_rib[AFI_IP6] = route_table_init();
	375	}
	376
	377	void nhrp_shortcut_terminate(void)
	378	{
	379	route_table_finish(shortcut_rib[AFI_IP]);
	380	route_table_finish(shortcut_rib[AFI_IP6]);
	381	}
	382
996c9314 LB	383	void nhrp_shortcut_foreach(afi_t afi,
	384	void (cb)(struct nhrp_shortcut , void *),
	385	void *ctx)
2fb975da TT	386	{
	387	struct route_table *rt = shortcut_rib[afi];
	388	struct route_node *rn;
	389	route_table_iter_t iter;
	390
996c9314 LB	391	if (!rt)
996c9314 LB	392	return;
2fb975da TT	393
	394	route_table_iter_init(&iter, rt);
	395	while ((rn = route_table_iter_next(&iter)) != NULL) {
996c9314 LB	396	if (rn->info)
996c9314 LB	397	cb(rn->info, ctx);
2fb975da TT	398	}
	399	route_table_iter_cleanup(&iter);
	400	}
	401
	402	struct purge_ctx {
	403	const struct prefix *p;
	404	int deleted;
	405	};
	406
	407	void nhrp_shortcut_purge(struct nhrp_shortcut *s, int force)
	408	{
	409	THREAD_OFF(s->t_timer);
	410	nhrp_reqid_free(&nhrp_packet_reqid, &s->reqid);
	411
	412	if (force) {
	413	/* Immediate purge on route with draw or pending shortcut */
ffa2c898 QY	414	thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 5,
ffa2c898 QY	415	&s->t_timer);
2fb975da TT	416	} else {
	417	/* Soft expire - force immediate renewal, but purge
	418	* in few seconds to make sure stale route is not
	419	* used too long. In practice most purges are caused
	420	* by hub bgp change, but target usually stays same.
	421	* This allows to keep nhrp route up, and to not
	422	* cause temporary rerouting via hubs causing latency
	423	* jitter. */
ffa2c898 QY	424	thread_add_timer_msec(master, nhrp_shortcut_do_purge, s, 3000,
ffa2c898 QY	425	&s->t_timer);
2fb975da TT	426	s->expiring = 1;
	427	nhrp_shortcut_check_use(s);
	428	}
	429	}
	430
	431	static void nhrp_shortcut_purge_prefix(struct nhrp_shortcut s, void ctx)
	432	{
	433	struct purge_ctx *pctx = ctx;
	434
	435	if (prefix_match(pctx->p, s->p))
	436	nhrp_shortcut_purge(s, pctx->deleted \|\| !s->cache);
	437	}
	438
	439	void nhrp_shortcut_prefix_change(const struct prefix *p, int deleted)
	440	{
	441	struct purge_ctx pctx = {
996c9314	442	.p = p, .deleted = deleted,
2fb975da	443	};
996c9314 LB	444	nhrp_shortcut_foreach(family2afi(PREFIX_FAMILY(p)),
996c9314 LB	445	nhrp_shortcut_purge_prefix, &pctx);
2fb975da	446	}