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- /* 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.
- */
- #include "nhrpd.h"
- #include "table.h"
- #include "memory.h"
- #include "thread.h"
- #include "log.h"
- #include "nhrp_protocol.h"
- 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_TIMER_ON(master, s->t_timer, nhrp_shortcut_do_purge, s, s->holding_time/3);
- 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_TIMER_ON(master, s->t_timer, nhrp_shortcut_do_expire, s, 2*holding_time/3);
- }
- }
- 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_TIMER_ON(master, s->t_timer, nhrp_shortcut_do_purge, s, 1);
- 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_TIMER_ON(master, s->t_timer, nhrp_shortcut_do_purge, s, 30);
- 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_TIMER_MSEC_ON(master, s->t_timer, nhrp_shortcut_do_purge, s, 5);
- } 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_TIMER_MSEC_ON(master, s->t_timer, nhrp_shortcut_do_purge, s, 3000);
- 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);
- }
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