diff options
Diffstat (limited to 'nhrpd/nhrp_shortcut.c')
| -rw-r--r-- | nhrpd/nhrp_shortcut.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/nhrpd/nhrp_shortcut.c b/nhrpd/nhrp_shortcut.c new file mode 100644 index 00000000..421f2886 --- /dev/null +++ b/nhrpd/nhrp_shortcut.c @@ -0,0 +1,402 @@ +/* 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 = 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); +} + |