--- /dev/null
+/*
+ * BIRD -- The Babel protocol
+ *
+ * Copyright (c) 2015--2016 Toke Hoiland-Jorgensen
+ *
+ * Can be freely distributed and used under the terms of the GNU GPL.
+ *
+ * This file contains the main routines for handling and sending TLVs, as
+ * well as timers and interaction with the nest.
+ */
+
+/**
+ * DOC: The Babel protocol
+ *
+ * Babel (RFC6126) is a loop-avoiding distance-vector routing protocol that is
+ * robust and efficient both in ordinary wired networks and in wireless mesh
+ * networks.
+ *
+ * The Babel protocol keeps state for each neighbour in a &babel_neighbor
+ * struct, tracking received Hello and I Heard You (IHU) messages. A
+ * &babel_interface struct keeps hello and update times for each interface, and
+ * a separate hello seqno is maintained for each interface.
+ *
+ * For each prefix, Babel keeps track of both the possible routes (with next hop
+ * and router IDs), as well as the feasibility distance for each prefix and
+ * router id. The prefix itself is tracked in a &babel_entry struct, while the
+ * possible routes for the prefix are tracked as &babel_route entries and the
+ * feasibility distance is maintained through &babel_source structures.
+ *
+ * The main route selection is done in babel_select_route(). This is called when
+ * an entry is updated by receiving updates from the network or when modified by
+ * internal timers. It performs feasibility checks on the available routes for
+ * the prefix and selects the one with the lowest metric to be announced to the
+ * core.
+ */
+
+#include <stdlib.h>
+#include "babel.h"
+
+
+#define OUR_ROUTE(r) (r->neigh == NULL)
+
+/*
+ * Is one number greater or equal than another mod 2^16? This is based on the
+ * definition of serial number space in RFC 1982. Note that arguments are of
+ * uint type to avoid integer promotion to signed integer.
+ */
+static inline int ge_mod64k(uint a, uint b)
+{ return (u16)(a - b) < 0x8000; }
+
+static void babel_dump_entry(struct babel_entry *e);
+static void babel_dump_route(struct babel_route *r);
+static void babel_select_route(struct babel_entry *e);
+static void babel_send_route_request(struct babel_entry *e, struct babel_neighbor *n);
+static void babel_send_wildcard_request(struct babel_iface *ifa);
+static int babel_cache_seqno_request(struct babel_proto *p, ip_addr prefix, u8 plen,
+ u64 router_id, u16 seqno);
+static void babel_trigger_iface_update(struct babel_iface *ifa);
+static void babel_trigger_update(struct babel_proto *p);
+static void babel_send_seqno_request(struct babel_entry *e);
+static inline void babel_kick_timer(struct babel_proto *p);
+static inline void babel_iface_kick_timer(struct babel_iface *ifa);
+
+
+/*
+ * Functions to maintain data structures
+ */
+
+static void
+babel_init_entry(struct fib_node *n)
+{
+ struct babel_entry *e = (void *) n;
+ e->proto = NULL;
+ e->selected_in = NULL;
+ e->selected_out = NULL;
+ e->updated = now;
+ init_list(&e->sources);
+ init_list(&e->routes);
+}
+
+static inline struct babel_entry *
+babel_find_entry(struct babel_proto *p, ip_addr prefix, u8 plen)
+{
+ return fib_find(&p->rtable, &prefix, plen);
+}
+
+static struct babel_entry *
+babel_get_entry(struct babel_proto *p, ip_addr prefix, u8 plen)
+{
+ struct babel_entry *e = fib_get(&p->rtable, &prefix, plen);
+ e->proto = p;
+ return e;
+}
+
+static struct babel_source *
+babel_find_source(struct babel_entry *e, u64 router_id)
+{
+ struct babel_source *s;
+
+ WALK_LIST(s, e->sources)
+ if (s->router_id == router_id)
+ return s;
+
+ return NULL;
+}
+
+static struct babel_source *
+babel_get_source(struct babel_entry *e, u64 router_id)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_source *s = babel_find_source(e, router_id);
+
+ if (s)
+ return s;
+
+ s = sl_alloc(p->source_slab);
+ s->router_id = router_id;
+ s->expires = now + BABEL_GARBAGE_INTERVAL;
+ s->seqno = 0;
+ s->metric = BABEL_INFINITY;
+ add_tail(&e->sources, NODE s);
+
+ return s;
+}
+
+static void
+babel_expire_sources(struct babel_entry *e)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_source *n, *nx;
+
+ WALK_LIST_DELSAFE(n, nx, e->sources)
+ {
+ if (n->expires && n->expires <= now)
+ {
+ rem_node(NODE n);
+ sl_free(p->source_slab, n);
+ }
+ }
+}
+
+static struct babel_route *
+babel_find_route(struct babel_entry *e, struct babel_neighbor *n)
+{
+ struct babel_route *r;
+
+ WALK_LIST(r, e->routes)
+ if (r->neigh == n)
+ return r;
+
+ return NULL;
+}
+
+static struct babel_route *
+babel_get_route(struct babel_entry *e, struct babel_neighbor *nbr)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_route *r = babel_find_route(e, nbr);
+
+ if (r)
+ return r;
+
+ r = sl_alloc(p->route_slab);
+ memset(r, 0, sizeof(*r));
+ r->e = e;
+ add_tail(&e->routes, NODE r);
+
+ if (nbr)
+ {
+ r->neigh = nbr;
+ r->expires = now + BABEL_GARBAGE_INTERVAL;
+ add_tail(&nbr->routes, NODE &r->neigh_route);
+ }
+
+ return r;
+}
+
+static void
+babel_flush_route(struct babel_route *r)
+{
+ struct babel_proto *p = r->e->proto;
+
+ DBG("Babel: Flush route %I/%d router_id %lR neigh %I\n",
+ r->e->n.prefix, r->e->n.pxlen, r->router_id, r->neigh ? r->neigh->addr : IPA_NONE);
+
+ rem_node(NODE r);
+
+ if (r->neigh)
+ rem_node(&r->neigh_route);
+
+ if (r->e->selected_in == r)
+ r->e->selected_in = NULL;
+
+ if (r->e->selected_out == r)
+ r->e->selected_out = NULL;
+
+ sl_free(p->route_slab, r);
+}
+
+static void
+babel_expire_route(struct babel_route *r)
+{
+ struct babel_proto *p = r->e->proto;
+ struct babel_entry *e = r->e;
+
+ TRACE(D_EVENTS, "Route expiry timer for %I/%d router-id %lR fired",
+ e->n.prefix, e->n.pxlen, r->router_id);
+
+ if (r->metric < BABEL_INFINITY)
+ {
+ r->metric = BABEL_INFINITY;
+ r->expires = now + r->expiry_interval;
+ }
+ else
+ {
+ babel_flush_route(r);
+ }
+}
+
+static void
+babel_refresh_route(struct babel_route *r)
+{
+ if (!OUR_ROUTE(r) && (r == r->e->selected_in))
+ babel_send_route_request(r->e, r->neigh);
+
+ r->refresh_time = 0;
+}
+
+static void
+babel_expire_routes(struct babel_proto *p)
+{
+ struct babel_entry *e;
+ struct babel_route *r, *rx;
+ struct fib_iterator fit;
+
+ FIB_ITERATE_INIT(&fit, &p->rtable);
+
+loop:
+ FIB_ITERATE_START(&p->rtable, &fit, n)
+ {
+ e = (struct babel_entry *) n;
+ int changed = 0;
+
+ WALK_LIST_DELSAFE(r, rx, e->routes)
+ {
+ if (r->refresh_time && r->refresh_time <= now)
+ babel_refresh_route(r);
+
+ if (r->expires && r->expires <= now)
+ {
+ babel_expire_route(r);
+ changed = 1;
+ }
+ }
+
+ if (changed)
+ {
+ /*
+ * We have to restart the iteration because there may be a cascade of
+ * synchronous events babel_select_route() -> nest table change ->
+ * babel_rt_notify() -> p->rtable change, invalidating hidden variables.
+ */
+
+ FIB_ITERATE_PUT(&fit, n);
+ babel_select_route(e);
+ goto loop;
+ }
+
+ babel_expire_sources(e);
+
+ /* Remove empty entries */
+ if (EMPTY_LIST(e->sources) && EMPTY_LIST(e->routes))
+ {
+ FIB_ITERATE_PUT(&fit, n);
+ fib_delete(&p->rtable, e);
+ goto loop;
+ }
+ }
+ FIB_ITERATE_END(n);
+}
+
+static struct babel_neighbor *
+babel_find_neighbor(struct babel_iface *ifa, ip_addr addr)
+{
+ struct babel_neighbor *nbr;
+
+ WALK_LIST(nbr, ifa->neigh_list)
+ if (ipa_equal(nbr->addr, addr))
+ return nbr;
+
+ return NULL;
+}
+
+static struct babel_neighbor *
+babel_get_neighbor(struct babel_iface *ifa, ip_addr addr)
+{
+ struct babel_neighbor *nbr = babel_find_neighbor(ifa, addr);
+
+ if (nbr)
+ return nbr;
+
+ nbr = mb_allocz(ifa->pool, sizeof(struct babel_neighbor));
+ nbr->ifa = ifa;
+ nbr->addr = addr;
+ nbr->txcost = BABEL_INFINITY;
+ init_list(&nbr->routes);
+ add_tail(&ifa->neigh_list, NODE nbr);
+
+ return nbr;
+}
+
+static void
+babel_flush_neighbor(struct babel_neighbor *nbr)
+{
+ struct babel_proto *p = nbr->ifa->proto;
+ node *n;
+
+ TRACE(D_EVENTS, "Flushing neighbor %I", nbr->addr);
+
+ WALK_LIST_FIRST(n, nbr->routes)
+ {
+ struct babel_route *r = SKIP_BACK(struct babel_route, neigh_route, n);
+ struct babel_entry *e = r->e;
+ int selected = (r == e->selected_in);
+
+ babel_flush_route(r);
+
+ if (selected)
+ babel_select_route(e);
+ }
+
+ rem_node(NODE nbr);
+ mb_free(nbr);
+}
+
+static void
+babel_expire_ihu(struct babel_neighbor *nbr)
+{
+ nbr->txcost = BABEL_INFINITY;
+}
+
+static void
+babel_expire_hello(struct babel_neighbor *nbr)
+{
+ nbr->hello_map <<= 1;
+
+ if (nbr->hello_cnt < 16)
+ nbr->hello_cnt++;
+
+ if (!nbr->hello_map)
+ babel_flush_neighbor(nbr);
+}
+
+static void
+babel_expire_neighbors(struct babel_proto *p)
+{
+ struct babel_iface *ifa;
+ struct babel_neighbor *nbr, *nbx;
+
+ WALK_LIST(ifa, p->interfaces)
+ {
+ WALK_LIST_DELSAFE(nbr, nbx, ifa->neigh_list)
+ {
+ if (nbr->ihu_expiry && nbr->ihu_expiry <= now)
+ babel_expire_ihu(nbr);
+
+ if (nbr->hello_expiry && nbr->hello_expiry <= now)
+ babel_expire_hello(nbr);
+ }
+ }
+}
+
+
+/*
+ * Best route selection
+ */
+
+/*
+ * From the RFC (section 3.5.1):
+ *
+ * a route advertisement carrying the quintuple (prefix, plen, router-id, seqno,
+ * metric) is feasible if one of the following conditions holds:
+ *
+ * - metric is infinite; or
+ *
+ * - no entry exists in the source table indexed by (id, prefix, plen); or
+ *
+ * - an entry (prefix, plen, router-id, seqno', metric') exists in the source
+ * table, and either
+ * - seqno' < seqno or
+ * - seqno = seqno' and metric < metric'.
+ */
+static inline int
+babel_is_feasible(struct babel_source *s, u16 seqno, u16 metric)
+{
+ return !s ||
+ (metric == BABEL_INFINITY) ||
+ (seqno > s->seqno) ||
+ ((seqno == s->seqno) && (metric < s->metric));
+}
+
+static u16
+babel_compute_rxcost(struct babel_neighbor *n)
+{
+ struct babel_iface *ifa = n->ifa;
+ u8 cnt, missed;
+ u16 map=n->hello_map;
+
+ if (!map) return BABEL_INFINITY;
+ cnt = u32_popcount(map); // number of bits set
+ missed = n->hello_cnt-cnt;
+
+ if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS)
+ {
+ /* ETX - Appendix 2.2 in the RFC.
+
+ beta = prob. of successful transmission.
+ rxcost = BABEL_RXCOST_WIRELESS/beta
+
+ Since: beta = 1-missed/n->hello_cnt = cnt/n->hello_cnt
+ Then: rxcost = BABEL_RXCOST_WIRELESS * n->hello_cnt / cnt
+ */
+ if (!cnt) return BABEL_INFINITY;
+ return BABEL_RXCOST_WIRELESS * n->hello_cnt / cnt;
+ }
+ else
+ {
+ /* k-out-of-j selection - Appendix 2.1 in the RFC. */
+ DBG("Babel: Missed %d hellos from %I\n", missed, n->addr);
+ /* Link is bad if more than half the expected hellos were lost */
+ return (missed > n->hello_cnt/2) ? BABEL_INFINITY : ifa->cf->rxcost;
+ }
+}
+
+
+static u16
+babel_compute_cost(struct babel_neighbor *n)
+{
+ struct babel_iface *ifa = n->ifa;
+ u16 rxcost = babel_compute_rxcost(n);
+ if (rxcost == BABEL_INFINITY) return rxcost;
+ else if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS)
+ {
+ /* ETX - Appendix 2.2 in the RFC */
+ return (MAX(n->txcost, BABEL_RXCOST_WIRELESS) * rxcost)/BABEL_RXCOST_WIRELESS;
+ }
+ else
+ {
+ /* k-out-of-j selection - Appendix 2.1 in the RFC. */
+ return n->txcost;
+ }
+}
+
+/* Simple additive metric - Appendix 3.1 in the RFC */
+static u16
+babel_compute_metric(struct babel_neighbor *n, uint metric)
+{
+ metric += babel_compute_cost(n);
+ return MIN(metric, BABEL_INFINITY);
+}
+
+
+/**
+ * babel_announce_rte - announce selected route to the core
+ * @p: Babel protocol instance
+ * @e: Babel route entry to announce
+ *
+ * This function announces a Babel entry to the core if it has a selected
+ * incoming path, and retracts it otherwise. If the selected entry has infinite
+ * metric, the route is announced as unreachable.
+ */
+static void
+babel_announce_rte(struct babel_proto *p, struct babel_entry *e)
+{
+ struct babel_route *r = e->selected_in;
+
+ if (r)
+ {
+ net *n = net_get(p->p.table, e->n.prefix, e->n.pxlen);
+ rta A = {
+ .src = p->p.main_source,
+ .source = RTS_BABEL,
+ .scope = SCOPE_UNIVERSE,
+ .cast = RTC_UNICAST,
+ .dest = r->metric == BABEL_INFINITY ? RTD_UNREACHABLE : RTD_ROUTER,
+ .flags = 0,
+ .from = r->neigh->addr,
+ .iface = r->neigh->ifa->iface,
+ };
+
+ if (r->metric < BABEL_INFINITY)
+ A.gw = r->next_hop;
+
+ rta *a = rta_lookup(&A);
+ rte *rte = rte_get_temp(a);
+ rte->u.babel.metric = r->metric;
+ rte->u.babel.router_id = r->router_id;
+ rte->net = n;
+ rte->pflags = 0;
+
+ rte_update(&p->p, n, rte);
+ }
+ else
+ {
+ /* Retraction */
+ net *n = net_find(p->p.table, e->n.prefix, e->n.pxlen);
+ rte_update(&p->p, n, NULL);
+ }
+}
+
+/**
+ * babel_select_route - select best route for given route entry
+ * @e: Babel entry to select the best route for
+ *
+ * Select the best feasible route for a given prefix among the routes received
+ * from peers, and propagate it to the nest. This just selects the feasible
+ * route with the lowest metric.
+ *
+ * If no feasible route is available for a prefix that previously had a route
+ * selected, a seqno request is sent to try to get a valid route. In the
+ * meantime, the route is marked as infeasible in the nest (to blackhole packets
+ * going to it, as per the RFC).
+ *
+ * If no feasible route is available, and no previous route is selected, the
+ * route is removed from the nest entirely.
+ */
+static void
+babel_select_route(struct babel_entry *e)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_route *r, *cur = e->selected_in;
+
+ /* try to find the best feasible route */
+ WALK_LIST(r, e->routes)
+ if (!OUR_ROUTE(r) && /* prevent propagating our own routes back to core */
+ (!cur || r->metric < cur->metric) &&
+ babel_is_feasible(babel_find_source(e, r->router_id), r->seqno, r->advert_metric))
+ cur = r;
+
+ if (cur && !OUR_ROUTE(cur) &&
+ ((!e->selected_in && cur->metric < BABEL_INFINITY) ||
+ (e->selected_in && cur->metric < e->selected_in->metric)))
+ {
+ TRACE(D_EVENTS, "Picked new route for prefix %I/%d: router id %lR metric %d",
+ e->n.prefix, e->n.pxlen, cur->router_id, cur->metric);
+
+ e->selected_in = cur;
+ e->updated = now;
+ babel_announce_rte(p, e);
+ }
+ else if (!cur || cur->metric == BABEL_INFINITY)
+ {
+ /* Couldn't find a feasible route. If we have a selected route, that means
+ it just became infeasible; so set it's metric to infinite and install it
+ (as unreachable), then send a seqno request.
+
+ babel_build_rte() will set the unreachable flag if the metric is BABEL_INFINITY.*/
+ if (e->selected_in)
+ {
+ TRACE(D_EVENTS, "Lost feasible route for prefix %I/%d",
+ e->n.prefix, e->n.pxlen);
+
+ e->selected_in->metric = BABEL_INFINITY;
+ e->updated = now;
+
+ babel_send_seqno_request(e);
+ babel_announce_rte(p, e);
+ }
+ else
+ {
+ /* No route currently selected, and no new one selected; this means we
+ don't have a route to this destination anymore (and were probably
+ called from an expiry timer). Remove the route from the nest. */
+ TRACE(D_EVENTS, "Flushing route for prefix %I/%d", e->n.prefix, e->n.pxlen);
+
+ e->selected_in = NULL;
+ e->updated = now;
+ babel_announce_rte(p, e);
+ }
+ }
+}
+
+/*
+ * Functions to send replies
+ */
+
+static void
+babel_send_ack(struct babel_iface *ifa, ip_addr dest, u16 nonce)
+{
+ struct babel_proto *p = ifa->proto;
+ union babel_msg msg = {};
+
+ TRACE(D_PACKETS, "Sending ACK to %I with nonce %d", dest, nonce);
+
+ msg.type = BABEL_TLV_ACK;
+ msg.ack.nonce = nonce;
+
+ babel_send_unicast(&msg, ifa, dest);
+}
+
+static void
+babel_build_ihu(union babel_msg *msg, struct babel_iface *ifa, struct babel_neighbor *n)
+{
+ struct babel_proto *p = ifa->proto;
+
+ msg->type = BABEL_TLV_IHU;
+ msg->ihu.addr = n->addr;
+ msg->ihu.rxcost = babel_compute_rxcost(n);
+ msg->ihu.interval = ifa->cf->ihu_interval;
+
+ TRACE(D_PACKETS, "Sending IHU for %I with rxcost %d interval %d",
+ msg->ihu.addr, msg->ihu.rxcost, msg->ihu.interval);
+}
+
+static void
+babel_send_ihu(struct babel_iface *ifa, struct babel_neighbor *n)
+{
+ union babel_msg msg = {};
+ babel_build_ihu(&msg, ifa, n);
+ babel_send_unicast(&msg, ifa, n->addr);
+}
+
+static void
+babel_send_ihus(struct babel_iface *ifa)
+{
+ struct babel_neighbor *n;
+ WALK_LIST(n, ifa->neigh_list)
+ {
+ union babel_msg msg = {};
+ babel_build_ihu(&msg, ifa, n);
+ babel_enqueue(&msg, ifa);
+ }
+}
+
+static void
+babel_send_hello(struct babel_iface *ifa, u8 send_ihu)
+{
+ struct babel_proto *p = ifa->proto;
+ union babel_msg msg = {};
+
+ msg.type = BABEL_TLV_HELLO;
+ msg.hello.seqno = ifa->hello_seqno++;
+ msg.hello.interval = ifa->cf->hello_interval;
+
+ TRACE(D_PACKETS, "Sending hello on %s with seqno %d interval %d",
+ ifa->ifname, msg.hello.seqno, msg.hello.interval);
+
+ babel_enqueue(&msg, ifa);
+
+ if (send_ihu)
+ babel_send_ihus(ifa);
+}
+
+static void
+babel_send_route_request(struct babel_entry *e, struct babel_neighbor *n)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_iface *ifa = n->ifa;
+ union babel_msg msg = {};
+
+ TRACE(D_PACKETS, "Sending route request for %I/%d to %I",
+ e->n.prefix, e->n.pxlen, n->addr);
+
+ msg.type = BABEL_TLV_ROUTE_REQUEST;
+ msg.route_request.prefix = e->n.prefix;
+ msg.route_request.plen = e->n.pxlen;
+
+ babel_send_unicast(&msg, ifa, n->addr);
+}
+
+static void
+babel_send_wildcard_request(struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ union babel_msg msg = {};
+
+ TRACE(D_PACKETS, "Sending wildcard route request on %s",
+ ifa->ifname);
+
+ msg.type = BABEL_TLV_ROUTE_REQUEST;
+ msg.route_request.full = 1;
+
+ babel_enqueue(&msg, ifa);
+}
+
+static void
+babel_send_seqno_request(struct babel_entry *e)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_route *r = e->selected_in;
+ struct babel_iface *ifa = NULL;
+ struct babel_source *s = NULL;
+ union babel_msg msg = {};
+
+ s = babel_find_source(e, r->router_id);
+ if (!s || !babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1))
+ return;
+
+ TRACE(D_PACKETS, "Sending seqno request for %I/%d router-id %lR seqno %d",
+ e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1);
+
+ msg.type = BABEL_TLV_SEQNO_REQUEST;
+ msg.seqno_request.plen = e->n.pxlen;
+ msg.seqno_request.seqno = s->seqno + 1;
+ msg.seqno_request.hop_count = BABEL_INITIAL_HOP_COUNT;
+ msg.seqno_request.router_id = r->router_id;
+ msg.seqno_request.prefix = e->n.prefix;
+
+ WALK_LIST(ifa, p->interfaces)
+ babel_enqueue(&msg, ifa);
+}
+
+static void
+babel_unicast_seqno_request(struct babel_route *r)
+{
+ struct babel_entry *e = r->e;
+ struct babel_proto *p = e->proto;
+ struct babel_iface *ifa = r->neigh->ifa;
+ struct babel_source *s = NULL;
+ union babel_msg msg = {};
+
+ s = babel_find_source(e, r->router_id);
+ if (!s || !babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1))
+ return;
+
+ TRACE(D_PACKETS, "Sending seqno request for %I/%d router-id %lR seqno %d",
+ e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1);
+
+ msg.type = BABEL_TLV_SEQNO_REQUEST;
+ msg.seqno_request.plen = e->n.pxlen;
+ msg.seqno_request.seqno = s->seqno + 1;
+ msg.seqno_request.hop_count = BABEL_INITIAL_HOP_COUNT;
+ msg.seqno_request.router_id = r->router_id;
+ msg.seqno_request.prefix = e->n.prefix;
+
+ babel_send_unicast(&msg, ifa, r->neigh->addr);
+}
+
+/**
+ * babel_send_update - send route table updates
+ * @ifa: Interface to transmit on
+ * @changed: Only send entries changed since this time
+ *
+ * This function produces update TLVs for all entries changed since the time
+ * indicated by the &changed parameter and queues them for transmission on the
+ * selected interface. During the process, the feasibility distance for each
+ * transmitted entry is updated.
+ */
+static void
+babel_send_update(struct babel_iface *ifa, bird_clock_t changed)
+{
+ struct babel_proto *p = ifa->proto;
+
+ FIB_WALK(&p->rtable, n)
+ {
+ struct babel_entry *e = (void *) n;
+ struct babel_route *r = e->selected_out;
+
+ if (!r)
+ continue;
+
+ /* Our own seqno might have changed, in which case we update the routes we
+ originate. */
+ if ((r->router_id == p->router_id) && (r->seqno < p->update_seqno))
+ {
+ r->seqno = p->update_seqno;
+ e->updated = now;
+ }
+
+ /* Skip routes that weren't updated since 'changed' time */
+ if (e->updated < changed)
+ continue;
+
+ TRACE(D_PACKETS, "Sending update for %I/%d router-id %lR seqno %d metric %d",
+ e->n.prefix, e->n.pxlen, r->router_id, r->seqno, r->metric);
+
+ union babel_msg msg = {};
+ msg.type = BABEL_TLV_UPDATE;
+ msg.update.plen = e->n.pxlen;
+ msg.update.interval = ifa->cf->update_interval;
+ msg.update.seqno = r->seqno;
+ msg.update.metric = r->metric;
+ msg.update.prefix = e->n.prefix;
+ msg.update.router_id = r->router_id;
+
+ /* Update feasibility distance */
+ struct babel_source *s = babel_get_source(e, r->router_id);
+ s->expires = now + BABEL_GARBAGE_INTERVAL;
+ if ((msg.update.seqno > s->seqno) ||
+ ((msg.update.seqno == s->seqno) && (msg.update.metric < s->metric)))
+ {
+ s->seqno = msg.update.seqno;
+ s->metric = msg.update.metric;
+ }
+ babel_enqueue(&msg, ifa);
+ }
+ FIB_WALK_END;
+}
+
+static void
+babel_trigger_iface_update(struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+
+ /* Interface not active or already scheduled */
+ if (!ifa->up || ifa->want_triggered)
+ return;
+
+ TRACE(D_EVENTS, "Scheduling triggered updates for %s seqno %d",
+ ifa->iface->name, p->update_seqno);
+
+ ifa->want_triggered = now;
+ babel_iface_kick_timer(ifa);
+}
+
+/* Sends and update on all interfaces. */
+static void
+babel_trigger_update(struct babel_proto *p)
+{
+ if (p->triggered)
+ return;
+
+ struct babel_iface *ifa;
+ WALK_LIST(ifa, p->interfaces)
+ babel_trigger_iface_update(ifa);
+
+ p->triggered = 1;
+}
+
+/* A retraction is an update with an infinite metric */
+static void
+babel_send_retraction(struct babel_iface *ifa, ip_addr prefix, int plen)
+{
+ struct babel_proto *p = ifa->proto;
+ union babel_msg msg = {};
+
+ TRACE(D_PACKETS, "Sending retraction for %I/%d router-id %lR seqno %d",
+ prefix, plen, p->router_id, p->update_seqno);
+
+ msg.type = BABEL_TLV_UPDATE;
+ msg.update.plen = plen;
+ msg.update.interval = ifa->cf->update_interval;
+ msg.update.seqno = p->update_seqno;
+ msg.update.metric = BABEL_INFINITY;
+ msg.update.prefix = prefix;
+ msg.update.router_id = p->router_id;
+
+ babel_enqueue(&msg, ifa);
+}
+
+
+/*
+ * TLV handler helpers
+ */
+
+/* Update hello history according to Appendix A1 of the RFC */
+static void
+babel_update_hello_history(struct babel_neighbor *n, u16 seqno, u16 interval)
+{
+ /*
+ * Compute the difference between expected and received seqno (modulo 2^16).
+ * If the expected and received seqnos are within 16 of each other, the modular
+ * difference is going to be less than 16 for one of the directions. Otherwise,
+ * the values differ too much, so just reset the state.
+ */
+
+ u16 delta = ((uint) seqno - (uint) n->next_hello_seqno);
+
+ if (delta == 0)
+ {
+ /* Do nothing */
+ }
+ else if (delta <= 16)
+ {
+ /* Sending node decreased interval; fast-forward */
+ n->hello_map <<= delta;
+ n->hello_cnt = MIN(n->hello_cnt + delta, 16);
+ }
+ else if (delta >= 0xfff0)
+ {
+ u8 diff = (0xffff - delta);
+ /* Sending node increased interval; undo history */
+ n->hello_map >>= diff;
+ n->hello_cnt = (diff < n->hello_cnt) ? n->hello_cnt - diff : 0;
+ }
+ else
+ {
+ /* Note state reset - flush entries */
+ n->hello_map = n->hello_cnt = 0;
+ }
+
+ /* Current entry */
+ n->hello_map = (n->hello_map << 1) | 1;
+ n->next_hello_seqno = seqno+1;
+ if (n->hello_cnt < 16) n->hello_cnt++;
+ n->hello_expiry = now + BABEL_HELLO_EXPIRY_FACTOR(interval);
+}
+
+static void
+babel_expire_seqno_requests(struct babel_proto *p)
+{
+ struct babel_seqno_request *n, *nx;
+ WALK_LIST_DELSAFE(n, nx, p->seqno_cache)
+ {
+ if ((n->updated + BABEL_SEQNO_REQUEST_EXPIRY) <= now)
+ {
+ rem_node(NODE n);
+ sl_free(p->seqno_slab, n);
+ }
+ }
+}
+
+/*
+ * Checks the seqno request cache for a matching request and returns failure if
+ * found. Otherwise, a new entry is stored in the cache.
+ */
+static int
+babel_cache_seqno_request(struct babel_proto *p, ip_addr prefix, u8 plen,
+ u64 router_id, u16 seqno)
+{
+ struct babel_seqno_request *r;
+
+ WALK_LIST(r, p->seqno_cache)
+ {
+ if (ipa_equal(r->prefix, prefix) && (r->plen == plen) &&
+ (r->router_id == router_id) && (r->seqno == seqno))
+ return 0;
+ }
+
+ /* no entries found */
+ r = sl_alloc(p->seqno_slab);
+ r->prefix = prefix;
+ r->plen = plen;
+ r->router_id = router_id;
+ r->seqno = seqno;
+ r->updated = now;
+ add_tail(&p->seqno_cache, NODE r);
+
+ return 1;
+}
+
+static void
+babel_forward_seqno_request(struct babel_entry *e,
+ struct babel_msg_seqno_request *in,
+ ip_addr sender)
+{
+ struct babel_proto *p = e->proto;
+ struct babel_route *r;
+
+ TRACE(D_PACKETS, "Forwarding seqno request for %I/%d router-id %lR seqno %d",
+ e->n.prefix, e->n.pxlen, in->router_id, in->seqno);
+
+ WALK_LIST(r, e->routes)
+ {
+ if ((r->router_id == in->router_id) &&
+ !OUR_ROUTE(r) &&
+ !ipa_equal(r->neigh->addr, sender))
+ {
+ if (!babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, in->router_id, in->seqno))
+ return;
+
+ union babel_msg msg = {};
+ msg.type = BABEL_TLV_SEQNO_REQUEST;
+ msg.seqno_request.plen = in->plen;
+ msg.seqno_request.seqno = in->seqno;
+ msg.seqno_request.hop_count = in->hop_count-1;
+ msg.seqno_request.router_id = in->router_id;
+ msg.seqno_request.prefix = e->n.prefix;
+
+ babel_send_unicast(&msg, r->neigh->ifa, r->neigh->addr);
+ return;
+ }
+ }
+}
+
+
+/*
+ * TLV handlers
+ */
+
+void
+babel_handle_ack_req(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_ack_req *msg = &m->ack_req;
+
+ TRACE(D_PACKETS, "Handling ACK request nonce %d interval %d",
+ msg->nonce, msg->interval);
+
+ babel_send_ack(ifa, msg->sender, msg->nonce);
+}
+
+void
+babel_handle_hello(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_hello *msg = &m->hello;
+
+ TRACE(D_PACKETS, "Handling hello seqno %d interval %d",
+ msg->seqno, msg->interval);
+
+ struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender);
+ babel_update_hello_history(n, msg->seqno, msg->interval);
+ if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS)
+ babel_send_ihu(ifa, n);
+}
+
+void
+babel_handle_ihu(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_ihu *msg = &m->ihu;
+
+ /* Ignore IHUs that are not about us */
+ if ((msg->ae != BABEL_AE_WILDCARD) && !ipa_equal(msg->addr, ifa->addr))
+ return;
+
+ TRACE(D_PACKETS, "Handling IHU rxcost %d interval %d",
+ msg->rxcost, msg->interval);
+
+ struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender);
+ n->txcost = msg->rxcost;
+ n->ihu_expiry = now + BABEL_IHU_EXPIRY_FACTOR(msg->interval);
+}
+
+/**
+ * babel_handle_update - handle incoming route updates
+ * @m: Incoming update TLV
+ * @ifa: Interface the update was received on
+ *
+ * This function is called as a handler for update TLVs and handles the updating
+ * and maintenance of route entries in Babel's internal routing cache. The
+ * handling follows the actions described in the Babel RFC, and at the end of
+ * each update handling, babel_select_route() is called on the affected entry to
+ * optionally update the selected routes and propagate them to the core.
+ */
+void
+babel_handle_update(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_update *msg = &m->update;
+
+ struct babel_neighbor *n;
+ struct babel_entry *e;
+ struct babel_source *s;
+ struct babel_route *r;
+ int feasible;
+
+ TRACE(D_PACKETS, "Handling update for %I/%d with seqno %d metric %d",
+ msg->prefix, msg->plen, msg->seqno, msg->metric);
+
+ n = babel_find_neighbor(ifa, msg->sender);
+ if (!n)
+ {
+ DBG("Babel: Haven't heard from neighbor %I; ignoring update.\n", msg->sender);
+ return;
+ }
+
+ if (msg->router_id == p->router_id)
+ {
+ DBG("Babel: Ignoring update for our own router ID.\n");
+ return;
+ }
+
+ /*
+ * RFC section 3.5.4:
+ *
+ * When a Babel node receives an update (id, prefix, seqno, metric) from a
+ * neighbour neigh with a link cost value equal to cost, it checks whether it
+ * already has a routing table entry indexed by (neigh, id, prefix).
+ *
+ * If no such entry exists:
+ *
+ * o if the update is unfeasible, it is ignored;
+ *
+ * o if the metric is infinite (the update is a retraction), the update is
+ * ignored;
+ *
+ * o otherwise, a new route table entry is created, indexed by (neigh, id,
+ * prefix), with seqno equal to seqno and an advertised metric equal to the
+ * metric carried by the update.
+ *
+ * If such an entry exists:
+ *
+ * o if the entry is currently installed and the update is unfeasible, then
+ * the behaviour depends on whether the router-ids of the two entries match.
+ * If the router-ids are different, the update is treated as though it were
+ * a retraction (i.e., as though the metric were FFFF hexadecimal). If the
+ * router-ids are equal, the update is ignored;
+ *
+ * o otherwise (i.e., if either the update is feasible or the entry is not
+ * currently installed), then the entry's sequence number, advertised
+ * metric, metric, and router-id are updated and, unless the advertised
+ * metric is infinite, the route's expiry timer is reset to a small multiple
+ * of the Interval value included in the update.
+ */
+
+ if (msg->metric == BABEL_INFINITY)
+ e = babel_find_entry(p, msg->prefix, msg->plen);
+ else
+ e = babel_get_entry(p, msg->prefix, msg->plen);
+
+ if (!e)
+ return;
+
+ s = babel_find_source(e, msg->router_id); /* for feasibility */
+ r = babel_find_route(e, n); /* the route entry indexed by neighbour */
+ feasible = babel_is_feasible(s, msg->seqno, msg->metric);
+
+ if (!r)
+ {
+ if (!feasible || (msg->metric == BABEL_INFINITY))
+ return;
+
+ r = babel_get_route(e, n);
+ r->advert_metric = msg->metric;
+ r->router_id = msg->router_id;
+ r->metric = babel_compute_metric(n, msg->metric);
+ r->next_hop = msg->next_hop;
+ r->seqno = msg->seqno;
+ }
+ else if (r == r->e->selected_in && !feasible)
+ {
+ /* Route is installed and update is infeasible - we may lose the route, so
+ send a unicast seqno request (section 3.8.2.2 second paragraph). */
+ babel_unicast_seqno_request(r);
+
+ if (msg->router_id == r->router_id) return;
+ r->metric = BABEL_INFINITY; /* retraction */
+ }
+ else
+ {
+ /* Last paragraph above - update the entry */
+ r->advert_metric = msg->metric;
+ r->metric = babel_compute_metric(n, msg->metric);
+ r->router_id = msg->router_id;
+ r->next_hop = msg->next_hop;
+ r->seqno = msg->seqno;
+
+ if (msg->metric != BABEL_INFINITY)
+ {
+ r->expiry_interval = BABEL_ROUTE_EXPIRY_FACTOR(msg->interval);
+ r->expires = now + r->expiry_interval;
+ if (r->expiry_interval > BABEL_ROUTE_REFRESH_INTERVAL)
+ r->refresh_time = now + r->expiry_interval - BABEL_ROUTE_REFRESH_INTERVAL;
+ }
+
+ /* If the route is not feasible at this point, it means it is from another
+ neighbour than the one currently selected; so send a unicast seqno
+ request to try to get a better route (section 3.8.2.2 last paragraph). */
+ if (!feasible)
+ babel_unicast_seqno_request(r);
+ }
+
+ babel_select_route(e);
+}
+
+void
+babel_handle_route_request(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_route_request *msg = &m->route_request;
+
+ /* RFC 6126 3.8.1.1 */
+
+ /* Wildcard request - full update on the interface */
+ if (msg->full)
+ {
+ TRACE(D_PACKETS, "Handling wildcard route request");
+ ifa->want_triggered = 1;
+ return;
+ }
+
+ TRACE(D_PACKETS, "Handling route request for %I/%d", msg->prefix, msg->plen);
+
+ /* Non-wildcard request - see if we have an entry for the route.
+ If not, send a retraction, otherwise send an update. */
+ struct babel_entry *e = babel_find_entry(p, msg->prefix, msg->plen);
+ if (!e)
+ {
+ babel_send_retraction(ifa, msg->prefix, msg->plen);
+ }
+ else
+ {
+ babel_trigger_iface_update(ifa);
+ e->updated = now;
+ }
+}
+
+
+void
+babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_seqno_request *msg = &m->seqno_request;
+
+ /* RFC 6126 3.8.1.2 */
+
+ TRACE(D_PACKETS, "Handling seqno request for %I/%d router-id %lR seqno %d hop count %d",
+ msg->prefix, msg->plen, msg->router_id, msg->seqno, msg->hop_count);
+
+ /* Ignore if we have no such entry or entry has infinite metric */
+ struct babel_entry *e = babel_find_entry(p, msg->prefix, msg->plen);
+ if (!e || !e->selected_out || (e->selected_out->metric == BABEL_INFINITY))
+ return;
+
+ /* Trigger update on incoming interface if we have a selected route with
+ different router id or seqno no smaller than requested */
+ struct babel_route *r = e->selected_out;
+ if ((r->router_id != msg->router_id) || ge_mod64k(r->seqno, msg->seqno))
+ {
+ babel_trigger_iface_update(ifa);
+ e->updated = now;
+ return;
+ }
+
+ /* Seqno is larger; check if we own the router id */
+ if (msg->router_id == p->router_id)
+ {
+ /* Ours; update seqno and trigger global update */
+ p->update_seqno++;
+ babel_trigger_update(p);
+ }
+ else
+ {
+ /* Not ours; forward if TTL allows it */
+ if (msg->hop_count > 1)
+ babel_forward_seqno_request(e, msg, msg->sender);
+ }
+}
+
+
+/*
+ * Babel interfaces
+ */
+
+/**
+ * babel_iface_timer - Babel interface timer handler
+ * @t: Timer
+ *
+ * This function is called by the per-interface timer and triggers sending of
+ * periodic Hello's and both triggered and periodic updates. Periodic Hello's
+ * and updates are simply handled by setting the next_{hello,regular} variables
+ * on the interface, and triggering an update (and resetting the variable)
+ * whenever 'now' exceeds that value.
+ *
+ * For triggered updates, babel_trigger_iface_update() will set the
+ * want_triggered field on the interface to a timestamp value. If this is set
+ * (and the next_triggered time has passed; this is a rate limiting mechanism),
+ * babel_send_update() will be called with this timestamp as the second
+ * parameter. This causes updates to be send consisting of only the routes that
+ * have changed since the time saved in want_triggered.
+ *
+ * Mostly when an update is triggered, the route being modified will be set to
+ * the value of 'now' at the time of the trigger; the >= comparison for
+ * selecting which routes to send in the update will make sure this is included.
+ */
+static void
+babel_iface_timer(timer *t)
+{
+ struct babel_iface *ifa = t->data;
+ struct babel_proto *p = ifa->proto;
+ bird_clock_t hello_period = ifa->cf->hello_interval;
+ bird_clock_t update_period = ifa->cf->update_interval;
+
+ if (now >= ifa->next_hello)
+ {
+ babel_send_hello(ifa, (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS ||
+ ifa->hello_seqno % BABEL_IHU_INTERVAL_FACTOR == 0));
+ ifa->next_hello += hello_period * (1 + (now - ifa->next_hello) / hello_period);
+ }
+
+ if (now >= ifa->next_regular)
+ {
+ TRACE(D_EVENTS, "Sending regular updates on %s", ifa->ifname);
+ babel_send_update(ifa, 0);
+ ifa->next_regular += update_period * (1 + (now - ifa->next_regular) / update_period);
+ ifa->want_triggered = 0;
+ p->triggered = 0;
+ }
+ else if (ifa->want_triggered && (now >= ifa->next_triggered))
+ {
+ TRACE(D_EVENTS, "Sending triggered updates on %s", ifa->ifname);
+ babel_send_update(ifa, ifa->want_triggered);
+ ifa->next_triggered = now + MIN(5, update_period / 2 + 1);
+ ifa->want_triggered = 0;
+ p->triggered = 0;
+ }
+
+ bird_clock_t next_event = MIN(ifa->next_hello, ifa->next_regular);
+ tm_start(ifa->timer, ifa->want_triggered ? 1 : (next_event - now));
+}
+
+static inline void
+babel_iface_kick_timer(struct babel_iface *ifa)
+{
+ if (ifa->timer->expires > (now + 1))
+ tm_start(ifa->timer, 1);
+}
+
+static void
+babel_iface_start(struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+
+ TRACE(D_EVENTS, "Starting interface %s", ifa->ifname);
+
+ ifa->next_hello = now + (random() % ifa->cf->hello_interval) + 1;
+ ifa->next_regular = now + (random() % ifa->cf->update_interval) + 1;
+ ifa->next_triggered = now + MIN(5, ifa->cf->update_interval / 2 + 1);
+ ifa->want_triggered = 0; /* We send an immediate update (below) */
+ tm_start(ifa->timer, 1);
+ ifa->up = 1;
+
+ babel_send_hello(ifa, 0);
+ babel_send_wildcard_request(ifa);
+ babel_send_update(ifa, 0); /* Full update */
+}
+
+static void
+babel_iface_stop(struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_neighbor *nbr;
+ struct babel_route *r;
+ node *n;
+
+ TRACE(D_EVENTS, "Stopping interface %s", ifa->ifname);
+
+ /*
+ * Rather than just flushing the neighbours, we set the metric of their routes
+ * to infinity. This allows us to keep the neighbour hello state for when the
+ * interface comes back up. The routes will also be kept until they expire.
+ */
+ WALK_LIST(nbr, ifa->neigh_list)
+ {
+ WALK_LIST(n, nbr->routes)
+ {
+ r = SKIP_BACK(struct babel_route, neigh_route, n);
+ r->metric = BABEL_INFINITY;
+ r->expires = now + r->expiry_interval;
+ babel_select_route(r->e);
+ }
+ }
+
+ tm_stop(ifa->timer);
+ ifa->up = 0;
+}
+
+static inline int
+babel_iface_link_up(struct babel_iface *ifa)
+{
+ return !ifa->cf->check_link || (ifa->iface->flags & IF_LINK_UP);
+}
+
+static void
+babel_iface_update_state(struct babel_iface *ifa)
+{
+ int up = ifa->sk && babel_iface_link_up(ifa);
+
+ if (up == ifa->up)
+ return;
+
+ if (up)
+ babel_iface_start(ifa);
+ else
+ babel_iface_stop(ifa);
+}
+
+static void
+babel_iface_update_buffers(struct babel_iface *ifa)
+{
+ if (!ifa->sk)
+ return;
+
+ uint mtu = MAX(BABEL_MIN_MTU, ifa->iface->mtu);
+ uint rbsize = ifa->cf->rx_buffer ?: mtu;
+ uint tbsize = ifa->cf->tx_length ?: mtu;
+ rbsize = MAX(rbsize, tbsize);
+
+ sk_set_rbsize(ifa->sk, rbsize);
+ sk_set_tbsize(ifa->sk, tbsize);
+
+ ifa->tx_length = tbsize - BABEL_OVERHEAD;
+}
+
+static struct babel_iface*
+babel_find_iface(struct babel_proto *p, struct iface *what)
+{
+ struct babel_iface *ifa;
+
+ WALK_LIST (ifa, p->interfaces)
+ if (ifa->iface == what)
+ return ifa;
+
+ return NULL;
+}
+
+static void
+babel_iface_locked(struct object_lock *lock)
+{
+ struct babel_iface *ifa = lock->data;
+ struct babel_proto *p = ifa->proto;
+
+ if (!babel_open_socket(ifa))
+ {
+ log(L_ERR "%s: Cannot open socket for %s", p->p.name, ifa->iface->name);
+ return;
+ }
+
+ babel_iface_update_buffers(ifa);
+ babel_iface_update_state(ifa);
+}
+
+static void
+babel_add_iface(struct babel_proto *p, struct iface *new, struct babel_iface_config *ic)
+{
+ struct babel_iface *ifa;
+
+ TRACE(D_EVENTS, "Adding interface %s", new->name);
+
+ pool *pool = rp_new(p->p.pool, new->name);
+
+ ifa = mb_allocz(pool, sizeof(struct babel_iface));
+ ifa->proto = p;
+ ifa->iface = new;
+ ifa->cf = ic;
+ ifa->pool = pool;
+ ifa->ifname = new->name;
+
+ add_tail(&p->interfaces, NODE ifa);
+
+ struct ifa *addr;
+ WALK_LIST(addr, new->addrs)
+ if (ipa_is_link_local(addr->ip))
+ ifa->addr = addr->ip;
+
+ if (ipa_zero(ifa->addr))
+ log(L_WARN "%s: Cannot find link-local addr on %s", p->p.name, new->name);
+
+ init_list(&ifa->neigh_list);
+ ifa->hello_seqno = 1;
+
+ ifa->timer = tm_new_set(ifa->pool, babel_iface_timer, ifa, 0, 0);
+
+ init_list(&ifa->msg_queue);
+ ifa->send_event = ev_new(ifa->pool);
+ ifa->send_event->hook = babel_send_queue;
+ ifa->send_event->data = ifa;
+
+ struct object_lock *lock = olock_new(ifa->pool);
+ lock->type = OBJLOCK_UDP;
+ lock->addr = IP6_BABEL_ROUTERS;
+ lock->port = ifa->cf->port;
+ lock->iface = ifa->iface;
+ lock->hook = babel_iface_locked;
+ lock->data = ifa;
+
+ olock_acquire(lock);
+}
+
+static void
+babel_remove_iface(struct babel_proto *p, struct babel_iface *ifa)
+{
+ TRACE(D_EVENTS, "Removing interface %s", ifa->iface->name);
+
+ struct babel_neighbor *n;
+ WALK_LIST_FIRST(n, ifa->neigh_list)
+ babel_flush_neighbor(n);
+
+ rem_node(NODE ifa);
+
+ rfree(ifa->pool); /* contains ifa itself, locks, socket, etc */
+}
+
+static void
+babel_if_notify(struct proto *P, unsigned flags, struct iface *iface)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_config *cf = (void *) P->cf;
+
+ if (iface->flags & IF_IGNORE)
+ return;
+
+ if (flags & IF_CHANGE_UP)
+ {
+ struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, iface->addr);
+
+ /* we only speak multicast */
+ if (!(iface->flags & IF_MULTICAST))
+ return;
+
+ if (ic)
+ babel_add_iface(p, iface, ic);
+
+ return;
+ }
+
+ struct babel_iface *ifa = babel_find_iface(p, iface);
+
+ if (!ifa)
+ return;
+
+ if (flags & IF_CHANGE_DOWN)
+ {
+ babel_remove_iface(p, ifa);
+ return;
+ }
+
+ if (flags & IF_CHANGE_MTU)
+ babel_iface_update_buffers(ifa);
+
+ if (flags & IF_CHANGE_LINK)
+ babel_iface_update_state(ifa);
+}
+
+static int
+babel_reconfigure_iface(struct babel_proto *p, struct babel_iface *ifa, struct babel_iface_config *new)
+{
+ struct babel_iface_config *old = ifa->cf;
+
+ /* Change of these options would require to reset the iface socket */
+ if ((new->port != old->port) ||
+ (new->tx_tos != old->tx_tos) ||
+ (new->tx_priority != old->tx_priority))
+ return 0;
+
+ TRACE(D_EVENTS, "Reconfiguring interface %s", ifa->iface->name);
+
+ ifa->cf = new;
+
+ if (ifa->next_regular > (now + new->update_interval))
+ ifa->next_regular = now + (random() % new->update_interval) + 1;
+
+ if ((new->tx_length != old->tx_length) || (new->rx_buffer != old->rx_buffer))
+ babel_iface_update_buffers(ifa);
+
+ if (new->check_link != old->check_link)
+ babel_iface_update_state(ifa);
+
+ if (ifa->up)
+ babel_iface_kick_timer(ifa);
+
+ return 1;
+}
+
+static void
+babel_reconfigure_ifaces(struct babel_proto *p, struct babel_config *cf)
+{
+ struct iface *iface;
+
+ WALK_LIST(iface, iface_list)
+ {
+ if (! (iface->flags & IF_UP))
+ continue;
+
+ struct babel_iface *ifa = babel_find_iface(p, iface);
+ struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
+
+ if (ifa && ic)
+ {
+ if (babel_reconfigure_iface(p, ifa, ic))
+ continue;
+
+ /* Hard restart */
+ log(L_INFO "%s: Restarting interface %s", p->p.name, ifa->iface->name);
+ babel_remove_iface(p, ifa);
+ babel_add_iface(p, iface, ic);
+ }
+
+ if (ifa && !ic)
+ babel_remove_iface(p, ifa);
+
+ if (!ifa && ic)
+ babel_add_iface(p, iface, ic);
+ }
+}
+
+
+/*
+ * Debugging and info output functions
+ */
+
+static void
+babel_dump_source(struct babel_source *s)
+{
+ debug("Source router_id %lR seqno %d metric %d expires %d\n",
+ s->router_id, s->seqno, s->metric, s->expires ? s->expires-now : 0);
+}
+
+static void
+babel_dump_route(struct babel_route *r)
+{
+ debug("Route neigh %I if %s seqno %d metric %d/%d router_id %lR expires %d\n",
+ r->neigh ? r->neigh->addr : IPA_NONE,
+ r->neigh ? r->neigh->ifa->ifname : "(none)",
+ r->seqno, r->advert_metric, r->metric,
+ r->router_id, r->expires ? r->expires-now : 0);
+}
+
+static void
+babel_dump_entry(struct babel_entry *e)
+{
+ struct babel_source *s;
+ struct babel_route *r;
+
+ debug("Babel: Entry %I/%d:\n", e->n.prefix, e->n.pxlen);
+
+ WALK_LIST(s,e->sources)
+ { debug(" "); babel_dump_source(s); }
+
+ WALK_LIST(r,e->routes)
+ {
+ debug(" ");
+ if (r == e->selected_out) debug("*");
+ if (r == e->selected_in) debug("+");
+ babel_dump_route(r);
+ }
+}
+
+static void
+babel_dump_neighbor(struct babel_neighbor *n)
+{
+ debug("Neighbor %I txcost %d hello_map %x next seqno %d expires %d/%d\n",
+ n->addr, n->txcost, n->hello_map, n->next_hello_seqno,
+ n->hello_expiry ? n->hello_expiry - now : 0,
+ n->ihu_expiry ? n->ihu_expiry - now : 0);
+}
+
+static void
+babel_dump_iface(struct babel_iface *ifa)
+{
+ struct babel_neighbor *n;
+
+ debug("Babel: Interface %s addr %I rxcost %d type %d hello seqno %d intervals %d %d\n",
+ ifa->ifname, ifa->addr, ifa->cf->rxcost, ifa->cf->type, ifa->hello_seqno,
+ ifa->cf->hello_interval, ifa->cf->update_interval);
+
+ WALK_LIST(n, ifa->neigh_list)
+ { debug(" "); babel_dump_neighbor(n); }
+}
+
+static void
+babel_dump(struct proto *P)
+{
+ struct babel_proto *p = (struct babel_proto *) P;
+ struct babel_iface *ifa;
+
+ debug("Babel: router id %lR update seqno %d\n", p->router_id, p->update_seqno);
+
+ WALK_LIST(ifa, p->interfaces)
+ babel_dump_iface(ifa);
+
+ FIB_WALK(&p->rtable, n)
+ {
+ babel_dump_entry((struct babel_entry *) n);
+ }
+ FIB_WALK_END;
+}
+
+static void
+babel_get_route_info(rte *rte, byte *buf, ea_list *attrs)
+{
+ buf += bsprintf(buf, " (%d/%d) [%lR]", rte->pref, rte->u.babel.metric, rte->u.babel.router_id);
+}
+
+static int
+babel_get_attr(eattr *a, byte *buf, int buflen UNUSED)
+{
+ switch (a->id)
+ {
+ case EA_BABEL_METRIC:
+ bsprintf(buf, "metric: %d", a->u.data);
+ return GA_FULL;
+
+ case EA_BABEL_ROUTER_ID:
+ {
+ u64 rid = 0;
+ memcpy(&rid, a->u.ptr->data, sizeof(u64));
+ bsprintf(buf, "router_id: %lR", rid);
+ return GA_FULL;
+ }
+
+ default:
+ return GA_UNKNOWN;
+ }
+}
+
+void
+babel_show_interfaces(struct proto *P, char *iff)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_iface *ifa = NULL;
+ struct babel_neighbor *nbr = NULL;
+
+ if (p->p.proto_state != PS_UP)
+ {
+ cli_msg(-1023, "%s: is not up", p->p.name);
+ cli_msg(0, "");
+ return;
+ }
+
+ cli_msg(-1023, "%s:", p->p.name);
+ cli_msg(-1023, "%-10s %-6s %7s %6s %6s",
+ "Interface", "State", "RX cost", "Nbrs", "Timer");
+
+ WALK_LIST(ifa, p->interfaces)
+ {
+ if (iff && !patmatch(iff, ifa->iface->name))
+ continue;
+
+ int nbrs = 0;
+ WALK_LIST(nbr, ifa->neigh_list)
+ nbrs++;
+
+ int timer = MIN(ifa->next_regular, ifa->next_hello) - now;
+ cli_msg(-1023, "%-10s %-6s %7u %6u %6u",
+ ifa->iface->name, (ifa->up ? "Up" : "Down"), ifa->cf->rxcost, nbrs, MAX(timer, 0));
+ }
+
+ cli_msg(0, "");
+}
+
+void
+babel_show_neighbors(struct proto *P, char *iff)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_iface *ifa = NULL;
+ struct babel_neighbor *n = NULL;
+ struct babel_route *r = NULL;
+
+ if (p->p.proto_state != PS_UP)
+ {
+ cli_msg(-1024, "%s: is not up", p->p.name);
+ cli_msg(0, "");
+ return;
+ }
+
+ cli_msg(-1024, "%s:", p->p.name);
+ cli_msg(-1024, "%-25s %-10s %6s %6s %10s",
+ "IP address", "Interface", "Metric", "Routes", "Next hello");
+
+ WALK_LIST(ifa, p->interfaces)
+ {
+ if (iff && !patmatch(iff, ifa->iface->name))
+ continue;
+
+ WALK_LIST(n, ifa->neigh_list)
+ {
+ int rts = 0;
+ WALK_LIST(r, n->routes)
+ rts++;
+
+ int timer = n->hello_expiry - now;
+ cli_msg(-1024, "%-25I %-10s %6u %6u %10u",
+ n->addr, ifa->iface->name, n->txcost, rts, MAX(timer, 0));
+ }
+ }
+
+ cli_msg(0, "");
+}
+
+void
+babel_show_entries(struct proto *P)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_entry *e = NULL;
+ struct babel_source *s = NULL;
+ struct babel_route *r = NULL;
+
+ char ipbuf[STD_ADDRESS_P_LENGTH+5];
+ char ridbuf[ROUTER_ID_64_LENGTH+1];
+
+ if (p->p.proto_state != PS_UP)
+ {
+ cli_msg(-1025, "%s: is not up", p->p.name);
+ cli_msg(0, "");
+ return;
+ }
+
+ cli_msg(-1025, "%s:", p->p.name);
+ cli_msg(-1025, "%-29s %-23s %6s %5s %7s %7s",
+ "Prefix", "Router ID", "Metric", "Seqno", "Expires", "Sources");
+
+ FIB_WALK(&p->rtable, n)
+ {
+ e = (struct babel_entry *) n;
+ r = e->selected_in ? e->selected_in : e->selected_out;
+
+ int srcs = 0;
+ WALK_LIST(s, e->sources)
+ srcs++;
+
+ bsprintf(ipbuf, "%I/%u", e->n.prefix, e->n.pxlen);
+
+ if (r)
+ {
+ if (r->router_id == p->router_id)
+ bsprintf(ridbuf, "%s", "<self>");
+ else
+ bsprintf(ridbuf, "%lR", r->router_id);
+
+ int time = r->expires ? r->expires - now : 0;
+ cli_msg(-1025, "%-29s %-23s %6u %5u %7u %7u",
+ ipbuf, ridbuf, r->metric, r->seqno, MAX(time, 0), srcs);
+ }
+ else
+ {
+ cli_msg(-1025, "%-29s %-44s %7u", ipbuf, "<pending>", srcs);
+ }
+ }
+ FIB_WALK_END;
+
+ cli_msg(0, "");
+}
+
+
+/*
+ * Babel protocol glue
+ */
+
+/**
+ * babel_timer - global timer hook
+ * @t: Timer
+ *
+ * This function is called by the global protocol instance timer and handles
+ * expiration of routes and neighbours as well as pruning of the seqno request
+ * cache.
+ */
+static void
+babel_timer(timer *t)
+{
+ struct babel_proto *p = t->data;
+
+ babel_expire_routes(p);
+ babel_expire_seqno_requests(p);
+ babel_expire_neighbors(p);
+}
+
+static inline void
+babel_kick_timer(struct babel_proto *p)
+{
+ if (p->timer->expires > (now + 1))
+ tm_start(p->timer, 1);
+}
+
+
+static struct ea_list *
+babel_prepare_attrs(struct linpool *pool, ea_list *next, uint metric, u64 router_id)
+{
+ struct ea_list *l = lp_alloc(pool, sizeof(struct ea_list) + 2*sizeof(eattr));
+ struct adata *rid = lp_alloc(pool, sizeof(struct adata) + sizeof(u64));
+ rid->length = sizeof(u64);
+ memcpy(&rid->data, &router_id, sizeof(u64));
+
+ l->next = next;
+ l->flags = EALF_SORTED;
+ l->count = 2;
+
+ l->attrs[0].id = EA_BABEL_METRIC;
+ l->attrs[0].flags = 0;
+ l->attrs[0].type = EAF_TYPE_INT | EAF_TEMP;
+ l->attrs[0].u.data = metric;
+
+ l->attrs[1].id = EA_BABEL_ROUTER_ID;
+ l->attrs[1].flags = 0;
+ l->attrs[1].type = EAF_TYPE_OPAQUE | EAF_TEMP;
+ l->attrs[1].u.ptr = rid;
+
+ return l;
+}
+
+
+static int
+babel_import_control(struct proto *P, struct rte **rt, struct ea_list **attrs, struct linpool *pool)
+{
+ struct babel_proto *p = (void *) P;
+
+ /* Prepare attributes with initial values */
+ if ((*rt)->attrs->source != RTS_BABEL)
+ *attrs = babel_prepare_attrs(pool, NULL, 0, p->router_id);
+
+ return 0;
+}
+
+static struct ea_list *
+babel_make_tmp_attrs(struct rte *rt, struct linpool *pool)
+{
+ return babel_prepare_attrs(pool, NULL, rt->u.babel.metric, rt->u.babel.router_id);
+}
+
+static void
+babel_store_tmp_attrs(struct rte *rt, struct ea_list *attrs)
+{
+ rt->u.babel.metric = ea_get_int(attrs, EA_BABEL_METRIC, 0);
+}
+
+/*
+ * babel_rt_notify - core tells us about new route (possibly our own),
+ * so store it into our data structures.
+ */
+static void
+babel_rt_notify(struct proto *P, struct rtable *table UNUSED, struct network *net,
+ struct rte *new, struct rte *old, struct ea_list *attrs)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_entry *e;
+ struct babel_route *r;
+
+ if (new)
+ {
+ /* Update */
+ e = babel_get_entry(p, net->n.prefix, net->n.pxlen);
+
+ if (new->attrs->src->proto != P)
+ {
+ r = babel_get_route(e, NULL);
+ r->seqno = p->update_seqno;
+ r->router_id = p->router_id;
+ r->metric = 0; /* FIXME: should be selectable */
+ }
+ else
+ r = e->selected_in;
+
+ if (r != e->selected_out)
+ {
+ e->selected_out = r;
+ e->updated = now;
+ babel_trigger_update(p);
+ }
+ }
+ else
+ {
+ /* Withdraw */
+ e = babel_find_entry(p, net->n.prefix, net->n.pxlen);
+ if (!e || !e->selected_out)
+ return;
+
+ if (OUR_ROUTE(e->selected_out))
+ {
+ /*
+ * We originate this route, so set its metric to infinity and set an
+ * expiry time. This causes a retraction to be sent, and later the route
+ * to be flushed once the hold time has passed.
+ */
+ e->selected_out->metric = BABEL_INFINITY;
+ e->selected_out->expires = now + BABEL_HOLD_TIME;
+ e->updated = now;
+ babel_trigger_update(p);
+ }
+ else
+ {
+ /*
+ * This is a route originating from someone else that was lost; presumably
+ * because an export filter was updated to filter it. This means we can't
+ * set the metric to infinity (it would be overridden on subsequent
+ * updates from the peer originating the route), so just clear the
+ * exported route.
+ *
+ * This causes peers to expire the route after a while (like if we just
+ * shut down), but it's the best we can do in these circumstances; and
+ * since export filters presumably aren't updated that often this is
+ * acceptable.
+ */
+ e->selected_out = NULL;
+ }
+ }
+}
+
+static int
+babel_rte_better(struct rte *new, struct rte *old)
+{
+ return new->u.babel.metric < old->u.babel.metric;
+}
+
+static int
+babel_rte_same(struct rte *new, struct rte *old)
+{
+ return ((new->u.babel.router_id == old->u.babel.router_id) &&
+ (new->u.babel.metric == old->u.babel.metric));
+}
+
+
+static struct proto *
+babel_init(struct proto_config *cfg)
+{
+ struct proto *P = proto_new(cfg, sizeof(struct babel_proto));
+
+ P->accept_ra_types = RA_OPTIMAL;
+ P->if_notify = babel_if_notify;
+ P->rt_notify = babel_rt_notify;
+ P->import_control = babel_import_control;
+ P->make_tmp_attrs = babel_make_tmp_attrs;
+ P->store_tmp_attrs = babel_store_tmp_attrs;
+ P->rte_better = babel_rte_better;
+ P->rte_same = babel_rte_same;
+
+ return P;
+}
+
+static int
+babel_start(struct proto *P)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_config *cf = (void *) P->cf;
+
+ fib_init(&p->rtable, P->pool, sizeof(struct babel_entry), 0, babel_init_entry);
+ init_list(&p->interfaces);
+ p->timer = tm_new_set(P->pool, babel_timer, p, 0, 1);
+ tm_start(p->timer, 2);
+ p->update_seqno = 1;
+ p->router_id = proto_get_router_id(&cf->c);
+
+ p->route_slab = sl_new(P->pool, sizeof(struct babel_route));
+ p->source_slab = sl_new(P->pool, sizeof(struct babel_source));
+ p->msg_slab = sl_new(P->pool, sizeof(struct babel_msg_node));
+ p->seqno_slab = sl_new(P->pool, sizeof(struct babel_seqno_request));
+ init_list(&p->seqno_cache);
+
+ p->log_pkt_tbf = (struct tbf){ .rate = 1, .burst = 5 };
+
+ return PS_UP;
+}
+
+static int
+babel_reconfigure(struct proto *P, struct proto_config *c)
+{
+ struct babel_proto *p = (void *) P;
+ struct babel_config *new = (void *) c;
+
+ TRACE(D_EVENTS, "Reconfiguring");
+
+ p->p.cf = c;
+ babel_reconfigure_ifaces(p, new);
+
+ babel_trigger_update(p);
+ babel_kick_timer(p);
+
+ return 1;
+}
+
+
+struct protocol proto_babel = {
+ .name = "Babel",
+ .template = "babel%d",
+ .attr_class = EAP_BABEL,
+ .preference = DEF_PREF_BABEL,
+ .config_size = sizeof(struct babel_config),
+ .init = babel_init,
+ .dump = babel_dump,
+ .start = babel_start,
+ .reconfigure = babel_reconfigure,
+ .get_route_info = babel_get_route_info,
+ .get_attr = babel_get_attr
+};
--- /dev/null
+/*
+ * BIRD -- The Babel protocol
+ *
+ * Copyright (c) 2015--2016 Toke Hoiland-Jorgensen
+ *
+ * Can be freely distributed and used under the terms of the GNU GPL.
+ *
+ * This file contains the packet and TLV handling code for the protocol.
+ */
+
+#include "babel.h"
+
+
+struct babel_pkt_header {
+ u8 magic;
+ u8 version;
+ u16 length;
+} PACKED;
+
+struct babel_tlv {
+ u8 type;
+ u8 length;
+ u8 value[0];
+} PACKED;
+
+struct babel_tlv_ack_req {
+ u8 type;
+ u8 length;
+ u16 reserved;
+ u16 nonce;
+ u16 interval;
+} PACKED;
+
+struct babel_tlv_ack {
+ u8 type;
+ u8 length;
+ u16 nonce;
+} PACKED;
+
+struct babel_tlv_hello {
+ u8 type;
+ u8 length;
+ u16 reserved;
+ u16 seqno;
+ u16 interval;
+} PACKED;
+
+struct babel_tlv_ihu {
+ u8 type;
+ u8 length;
+ u8 ae;
+ u8 reserved;
+ u16 rxcost;
+ u16 interval;
+ u8 addr[0];
+} PACKED;
+
+struct babel_tlv_router_id {
+ u8 type;
+ u8 length;
+ u16 reserved;
+ u64 router_id;
+} PACKED;
+
+struct babel_tlv_next_hop {
+ u8 type;
+ u8 length;
+ u8 ae;
+ u8 reserved;
+ u8 addr[0];
+} PACKED;
+
+struct babel_tlv_update {
+ u8 type;
+ u8 length;
+ u8 ae;
+ u8 flags;
+ u8 plen;
+ u8 omitted;
+ u16 interval;
+ u16 seqno;
+ u16 metric;
+ u8 addr[0];
+} PACKED;
+
+struct babel_tlv_route_request {
+ u8 type;
+ u8 length;
+ u8 ae;
+ u8 plen;
+ u8 addr[0];
+} PACKED;
+
+struct babel_tlv_seqno_request {
+ u8 type;
+ u8 length;
+ u8 ae;
+ u8 plen;
+ u16 seqno;
+ u8 hop_count;
+ u8 reserved;
+ u64 router_id;
+ u8 addr[0];
+} PACKED;
+
+
+#define BABEL_FLAG_DEF_PREFIX 0x80
+#define BABEL_FLAG_ROUTER_ID 0x40
+
+
+struct babel_parse_state {
+ struct babel_proto *proto;
+ struct babel_iface *ifa;
+ ip_addr saddr;
+ ip_addr next_hop;
+ u64 router_id; /* Router ID used in subsequent updates */
+ u8 def_ip6_prefix[16]; /* Implicit IPv6 prefix in network order */
+ u8 def_ip4_prefix[4]; /* Implicit IPv4 prefix in network order */
+ u8 router_id_seen; /* router_id field is valid */
+ u8 def_ip6_prefix_seen; /* def_ip6_prefix is valid */
+ u8 def_ip4_prefix_seen; /* def_ip4_prefix is valid */
+};
+
+enum parse_result {
+ PARSE_SUCCESS,
+ PARSE_ERROR,
+ PARSE_IGNORE,
+};
+
+struct babel_write_state {
+ u64 router_id;
+ u8 router_id_seen;
+// ip_addr next_hop;
+};
+
+
+#define DROP(DSC,VAL) do { err_dsc = DSC; err_val = VAL; goto drop; } while(0)
+#define DROP1(DSC) do { err_dsc = DSC; goto drop; } while(0)
+#define LOG_PKT(msg, args...) \
+ log_rl(&p->log_pkt_tbf, L_REMOTE "%s: " msg, p->p.name, args)
+
+#define FIRST_TLV(p) ((struct babel_tlv *) (((struct babel_pkt_header *) p) + 1))
+#define NEXT_TLV(t) ((struct babel_tlv *) (((byte *) t) + TLV_LENGTH(t)))
+#define TLV_LENGTH(t) (t->type == BABEL_TLV_PAD1 ? 1 : t->length + sizeof(struct babel_tlv))
+#define TLV_OPT_LENGTH(t) (t->length + sizeof(struct babel_tlv) - sizeof(*t))
+#define TLV_HDR(tlv,t,l) ({ tlv->type = t; tlv->length = l - sizeof(struct babel_tlv); })
+#define TLV_HDR0(tlv,t) TLV_HDR(tlv, t, tlv_data[t].min_length)
+
+
+static inline u16
+get_time16(const void *p)
+{
+ u16 v = get_u16(p) / BABEL_TIME_UNITS;
+ return MAX(1, v);
+}
+
+static inline void
+put_time16(void *p, u16 v)
+{
+ put_u16(p, v * BABEL_TIME_UNITS);
+}
+
+static inline ip6_addr
+get_ip6_px(const void *p, int plen)
+{
+ ip6_addr addr = IPA_NONE;
+ memcpy(&addr, p, (plen + 7) / 8);
+ return ip6_ntoh(addr);
+}
+
+static inline void
+put_ip6_px(void *p, ip6_addr addr, int plen)
+{
+ addr = ip6_hton(addr);
+ memcpy(p, &addr, (plen + 7) / 8);
+}
+
+static inline ip6_addr
+get_ip6_ll(const void *p)
+{
+ return ip6_build(0xfe800000, 0, get_u32(p+0), get_u32(p+4));
+}
+
+static inline void
+put_ip6_ll(void *p, ip6_addr addr)
+{
+ put_u32(p+0, _I2(addr));
+ put_u32(p+4, _I3(addr));
+}
+
+
+/*
+ * TLV read/write functions
+ */
+
+static int babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_router_id(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+static int babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
+
+static int babel_write_ack(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+static int babel_write_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+static int babel_write_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+static int babel_write_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+static int babel_write_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+static int babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, int max_len);
+
+struct babel_tlv_data {
+ u8 min_length;
+ int (*read_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_parse_state *state);
+ int (*write_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_write_state *state, int max_len);
+ void (*handle_tlv)(union babel_msg *m, struct babel_iface *ifa);
+};
+
+const static struct babel_tlv_data tlv_data[BABEL_TLV_MAX] = {
+ [BABEL_TLV_ACK_REQ] = {
+ sizeof(struct babel_tlv_ack_req),
+ babel_read_ack_req,
+ NULL,
+ babel_handle_ack_req
+ },
+ [BABEL_TLV_ACK] = {
+ sizeof(struct babel_tlv_ack),
+ NULL,
+ babel_write_ack,
+ NULL
+ },
+ [BABEL_TLV_HELLO] = {
+ sizeof(struct babel_tlv_hello),
+ babel_read_hello,
+ babel_write_hello,
+ babel_handle_hello
+ },
+ [BABEL_TLV_IHU] = {
+ sizeof(struct babel_tlv_ihu),
+ babel_read_ihu,
+ babel_write_ihu,
+ babel_handle_ihu
+ },
+ [BABEL_TLV_ROUTER_ID] = {
+ sizeof(struct babel_tlv_router_id),
+ babel_read_router_id,
+ NULL,
+ NULL
+ },
+ [BABEL_TLV_NEXT_HOP] = {
+ sizeof(struct babel_tlv_next_hop),
+ babel_read_next_hop,
+ NULL,
+ NULL
+ },
+ [BABEL_TLV_UPDATE] = {
+ sizeof(struct babel_tlv_update),
+ babel_read_update,
+ babel_write_update,
+ babel_handle_update
+ },
+ [BABEL_TLV_ROUTE_REQUEST] = {
+ sizeof(struct babel_tlv_route_request),
+ babel_read_route_request,
+ babel_write_route_request,
+ babel_handle_route_request
+ },
+ [BABEL_TLV_SEQNO_REQUEST] = {
+ sizeof(struct babel_tlv_seqno_request),
+ babel_read_seqno_request,
+ babel_write_seqno_request,
+ babel_handle_seqno_request
+ },
+};
+
+static int
+babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_ack_req *tlv = (void *) hdr;
+ struct babel_msg_ack_req *msg = &m->ack_req;
+
+ msg->type = BABEL_TLV_ACK_REQ;
+ msg->nonce = get_u16(&tlv->nonce);
+ msg->interval = get_time16(&tlv->interval);
+ msg->sender = state->saddr;
+
+ if (!msg->interval)
+ return PARSE_ERROR;
+
+ return PARSE_SUCCESS;
+}
+
+static int
+babel_write_ack(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_ack *tlv = (void *) hdr;
+ struct babel_msg_ack *msg = &m->ack;
+
+ TLV_HDR0(tlv, BABEL_TLV_ACK);
+ put_u16(&tlv->nonce, msg->nonce);
+
+ return sizeof(struct babel_tlv_ack);
+}
+
+static int
+babel_read_hello(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_hello *tlv = (void *) hdr;
+ struct babel_msg_hello *msg = &m->hello;
+
+ msg->type = BABEL_TLV_HELLO;
+ msg->seqno = get_u16(&tlv->seqno);
+ msg->interval = get_time16(&tlv->interval);
+ msg->sender = state->saddr;
+
+ return PARSE_SUCCESS;
+}
+
+static int
+babel_write_hello(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_hello *tlv = (void *) hdr;
+ struct babel_msg_hello *msg = &m->hello;
+
+ TLV_HDR0(tlv, BABEL_TLV_HELLO);
+ put_u16(&tlv->seqno, msg->seqno);
+ put_time16(&tlv->interval, msg->interval);
+
+ return sizeof(struct babel_tlv_hello);
+}
+
+static int
+babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_ihu *tlv = (void *) hdr;
+ struct babel_msg_ihu *msg = &m->ihu;
+
+ msg->type = BABEL_TLV_IHU;
+ msg->ae = tlv->ae;
+ msg->rxcost = get_u16(&tlv->rxcost);
+ msg->interval = get_time16(&tlv->interval);
+ msg->addr = IPA_NONE;
+ msg->sender = state->saddr;
+
+ if (msg->ae >= BABEL_AE_MAX)
+ return PARSE_IGNORE;
+
+ // We handle link-local IPs. In every other case, the addr field will be 0 but
+ // validation will succeed. The handler takes care of these cases.
+ if (msg->ae == BABEL_AE_IP6_LL)
+ {
+ if (TLV_OPT_LENGTH(tlv) < 8)
+ return PARSE_ERROR;
+
+ msg->addr = ipa_from_ip6(get_ip6_ll(&tlv->addr));
+ }
+
+ return PARSE_SUCCESS;
+}
+
+static int
+babel_write_ihu(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_ihu *tlv = (void *) hdr;
+ struct babel_msg_ihu *msg = &m->ihu;
+
+ if (ipa_is_link_local(msg->addr) && max_len < sizeof(struct babel_tlv_ihu) + 8)
+ return 0;
+
+ TLV_HDR0(tlv, BABEL_TLV_IHU);
+ put_u16(&tlv->rxcost, msg->rxcost);
+ put_time16(&tlv->interval, msg->interval);
+
+ if (!ipa_is_link_local(msg->addr))
+ {
+ tlv->ae = BABEL_AE_WILDCARD;
+ return sizeof(struct babel_tlv_ihu);
+ }
+ put_ip6_ll(&tlv->addr, msg->addr);
+ tlv->ae = BABEL_AE_IP6_LL;
+ hdr->length += 8;
+ return sizeof(struct babel_tlv_ihu) + 8;
+}
+
+static int
+babel_read_router_id(struct babel_tlv *hdr, union babel_msg *m UNUSED,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_router_id *tlv = (void *) hdr;
+
+ state->router_id = get_u64(&tlv->router_id);
+ state->router_id_seen = 1;
+
+ return PARSE_IGNORE;
+}
+
+/* This is called directly from babel_write_update() */
+static int
+babel_write_router_id(struct babel_tlv *hdr, u64 router_id,
+ struct babel_write_state *state, int max_len UNUSED)
+{
+ struct babel_tlv_router_id *tlv = (void *) hdr;
+
+ /* We still assume that first min_length bytes are available and zeroed */
+
+ TLV_HDR0(tlv, BABEL_TLV_ROUTER_ID);
+ put_u64(&tlv->router_id, router_id);
+
+ state->router_id = router_id;
+ state->router_id_seen = 1;
+
+ return sizeof(struct babel_tlv_router_id);
+}
+
+static int
+babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *m UNUSED,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_next_hop *tlv = (void *) hdr;
+
+ switch (tlv->ae)
+ {
+ case BABEL_AE_WILDCARD:
+ return PARSE_ERROR;
+
+ case BABEL_AE_IP4:
+ /* TODO */
+ return PARSE_IGNORE;
+
+ case BABEL_AE_IP6:
+ if (TLV_OPT_LENGTH(tlv) < sizeof(ip6_addr))
+ return PARSE_ERROR;
+
+ state->next_hop = ipa_from_ip6(get_ip6(&tlv->addr));
+ return PARSE_IGNORE;
+
+ case BABEL_AE_IP6_LL:
+ if (TLV_OPT_LENGTH(tlv) < 8)
+ return PARSE_ERROR;
+
+ state->next_hop = ipa_from_ip6(get_ip6_ll(&tlv->addr));
+ return PARSE_IGNORE;
+
+ default:
+ return PARSE_IGNORE;
+ }
+
+ return PARSE_IGNORE;
+}
+
+static int
+babel_read_update(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_update *tlv = (void *) hdr;
+ struct babel_msg_update *msg = &m->update;
+
+ msg->type = BABEL_TLV_UPDATE;
+ msg->ae = tlv->ae;
+ msg->interval = get_time16(&tlv->interval);
+ msg->seqno = get_u16(&tlv->seqno);
+ msg->metric = get_u16(&tlv->metric);
+
+ /* Length of received prefix data without omitted part */
+ int len = (tlv->plen + 7)/8 - (int) tlv->omitted;
+ u8 buf[16] = {};
+
+ if ((len < 0) || (len > TLV_OPT_LENGTH(tlv)))
+ return PARSE_ERROR;
+
+ switch (tlv->ae)
+ {
+ case BABEL_AE_WILDCARD:
+ if (tlv->plen > 0)
+ return PARSE_ERROR;
+
+ msg->prefix = IPA_NONE;
+ break;
+
+ case BABEL_AE_IP4:
+ /* TODO */
+ return PARSE_IGNORE;
+
+ case BABEL_AE_IP6:
+ if (tlv->plen > MAX_PREFIX_LENGTH)
+ return PARSE_ERROR;
+
+ /* Cannot omit data if there is no saved prefix */
+ if (tlv->omitted && !state->def_ip6_prefix_seen)
+ return PARSE_ERROR;
+
+ /* Merge saved prefix and received prefix parts */
+ memcpy(buf, state->def_ip6_prefix, tlv->omitted);
+ memcpy(buf + tlv->omitted, tlv->addr, len);
+
+ msg->plen = tlv->plen;
+ msg->prefix = ipa_from_ip6(get_ip6(buf));
+
+ if (tlv->flags & BABEL_FLAG_DEF_PREFIX)
+ {
+ put_ip6(state->def_ip6_prefix, msg->prefix);
+ state->def_ip6_prefix_seen = 1;
+ }
+
+ if (tlv->flags & BABEL_FLAG_ROUTER_ID)
+ {
+ state->router_id = ((u64) _I2(msg->prefix)) << 32 | _I3(msg->prefix);
+ state->router_id_seen = 1;
+ }
+ break;
+
+ case BABEL_AE_IP6_LL:
+ /* ??? */
+ return PARSE_IGNORE;
+
+ default:
+ return PARSE_IGNORE;
+ }
+
+ if (!state->router_id_seen)
+ {
+ DBG("Babel: No router ID seen before update\n");
+ return PARSE_ERROR;
+ }
+
+ msg->router_id = state->router_id;
+ msg->next_hop = state->next_hop;
+ msg->sender = state->saddr;
+
+ return PARSE_SUCCESS;
+}
+
+static int
+babel_write_update(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_update *tlv = (void *) hdr;
+ struct babel_msg_update *msg = &m->update;
+ int len0 = 0;
+
+ /*
+ * When needed, we write Router-ID TLV before Update TLV and return size of
+ * both of them. There is enough space for the Router-ID TLV, because
+ * sizeof(struct babel_tlv_router_id) == sizeof(struct babel_tlv_update).
+ */
+ if (!state->router_id_seen || (msg->router_id != state->router_id))
+ {
+ len0 = babel_write_router_id(hdr, msg->router_id, state, max_len);
+ tlv = (struct babel_tlv_update *) NEXT_TLV(tlv);
+ }
+
+ int len = sizeof(struct babel_tlv_update) + (msg->plen + 7)/8;
+
+ if (len0 + len > max_len)
+ return 0;
+
+ memset(tlv, 0, sizeof(struct babel_tlv_update));
+ TLV_HDR(tlv, BABEL_TLV_UPDATE, len);
+ tlv->ae = BABEL_AE_IP6;
+ tlv->plen = msg->plen;
+ put_time16(&tlv->interval, msg->interval);
+ put_u16(&tlv->seqno, msg->seqno);
+ put_u16(&tlv->metric, msg->metric);
+ put_ip6_px(tlv->addr, msg->prefix, msg->plen);
+
+ return len0 + len;
+}
+
+static int
+babel_read_route_request(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_route_request *tlv = (void *) hdr;
+ struct babel_msg_route_request *msg = &m->route_request;
+
+ msg->type = BABEL_TLV_ROUTE_REQUEST;
+
+ switch (tlv->ae)
+ {
+ case BABEL_AE_WILDCARD:
+ /* Wildcard requests must have plen 0 */
+ if (tlv->plen > 0)
+ return PARSE_ERROR;
+
+ msg->full = 1;
+ return PARSE_SUCCESS;
+
+ case BABEL_AE_IP4:
+ /* TODO */
+ return PARSE_IGNORE;
+
+ case BABEL_AE_IP6:
+ if (tlv->plen > MAX_PREFIX_LENGTH)
+ return PARSE_ERROR;
+
+ if (TLV_OPT_LENGTH(tlv) < (tlv->plen + 7)/8)
+ return PARSE_ERROR;
+
+ msg->plen = tlv->plen;
+ msg->prefix = get_ip6_px(tlv->addr, tlv->plen);
+ return PARSE_SUCCESS;
+
+ case BABEL_AE_IP6_LL:
+ return PARSE_ERROR;
+
+ default:
+ return PARSE_IGNORE;
+ }
+
+ return PARSE_IGNORE;
+}
+
+static int
+babel_write_route_request(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_route_request *tlv = (void *) hdr;
+ struct babel_msg_route_request *msg = &m->route_request;
+
+ int len = sizeof(struct babel_tlv_route_request) + (msg->plen + 7)/8;
+
+ if (len > max_len)
+ return 0;
+
+ TLV_HDR(tlv, BABEL_TLV_ROUTE_REQUEST, len);
+
+ if (msg->full)
+ {
+ tlv->ae = BABEL_AE_WILDCARD;
+ tlv->plen = 0;
+ }
+ else
+ {
+ tlv->ae = BABEL_AE_IP6;
+ tlv->plen = msg->plen;
+ put_ip6_px(tlv->addr, msg->prefix, msg->plen);
+ }
+
+ return len;
+}
+
+static int
+babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_parse_state *state)
+{
+ struct babel_tlv_seqno_request *tlv = (void *) hdr;
+ struct babel_msg_seqno_request *msg = &m->seqno_request;
+
+ msg->type = BABEL_TLV_SEQNO_REQUEST;
+ msg->seqno = get_u16(&tlv->seqno);
+ msg->hop_count = tlv->hop_count;
+ msg->router_id = get_u64(&tlv->router_id);
+ msg->sender = state->saddr;
+
+ if (tlv->hop_count == 0)
+ return PARSE_ERROR;
+
+ switch (tlv->ae)
+ {
+ case BABEL_AE_WILDCARD:
+ return PARSE_ERROR;
+
+ case BABEL_AE_IP4:
+ /* TODO */
+ return PARSE_IGNORE;
+
+ case BABEL_AE_IP6:
+ if (tlv->plen > MAX_PREFIX_LENGTH)
+ return PARSE_ERROR;
+
+ if (TLV_OPT_LENGTH(tlv) < (tlv->plen + 7)/8)
+ return PARSE_ERROR;
+
+ msg->plen = tlv->plen;
+ msg->prefix = get_ip6_px(tlv->addr, tlv->plen);
+ return PARSE_SUCCESS;
+
+ case BABEL_AE_IP6_LL:
+ return PARSE_ERROR;
+
+ default:
+ return PARSE_IGNORE;
+ }
+
+ return PARSE_IGNORE;
+}
+
+static int
+babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *m,
+ struct babel_write_state *state, int max_len)
+{
+ struct babel_tlv_seqno_request *tlv = (void *) hdr;
+ struct babel_msg_seqno_request *msg = &m->seqno_request;
+
+ int len = sizeof(struct babel_tlv_seqno_request) + (msg->plen + 7)/8;
+
+ if (len > max_len)
+ return 0;
+
+ TLV_HDR(tlv, BABEL_TLV_SEQNO_REQUEST, len);
+ tlv->ae = BABEL_AE_IP6;
+ tlv->plen = msg->plen;
+ put_u16(&tlv->seqno, msg->seqno);
+ tlv->hop_count = msg->hop_count;
+ put_u64(&tlv->router_id, msg->router_id);
+ put_ip6_px(tlv->addr, msg->prefix, msg->plen);
+
+ return len;
+}
+
+static inline int
+babel_read_tlv(struct babel_tlv *hdr,
+ union babel_msg *msg,
+ struct babel_parse_state *state)
+{
+ if ((hdr->type <= BABEL_TLV_PADN) ||
+ (hdr->type >= BABEL_TLV_MAX) ||
+ !tlv_data[hdr->type].read_tlv)
+ return PARSE_IGNORE;
+
+ if (TLV_LENGTH(hdr) < tlv_data[hdr->type].min_length)
+ return PARSE_ERROR;
+
+ memset(msg, 0, sizeof(*msg));
+ return tlv_data[hdr->type].read_tlv(hdr, msg, state);
+}
+
+static int
+babel_write_tlv(struct babel_tlv *hdr,
+ union babel_msg *msg,
+ struct babel_write_state *state,
+ int max_len)
+{
+ if ((msg->type <= BABEL_TLV_PADN) ||
+ (msg->type >= BABEL_TLV_MAX) ||
+ !tlv_data[msg->type].write_tlv)
+ return 0;
+
+ if (tlv_data[msg->type].min_length > max_len)
+ return 0;
+
+ memset(hdr, 0, tlv_data[msg->type].min_length);
+ return tlv_data[msg->type].write_tlv(hdr, msg, state, max_len);
+}
+
+
+/*
+ * Packet RX/TX functions
+ */
+
+static int
+babel_send_to(struct babel_iface *ifa, ip_addr dest)
+{
+ sock *sk = ifa->sk;
+ struct babel_pkt_header *hdr = (void *) sk->tbuf;
+ int len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header);
+
+ DBG("Babel: Sending %d bytes to %I\n", len, dest);
+ return sk_send_to(sk, len, dest, 0);
+}
+
+/**
+ * babel_write_queue - Write a TLV queue to a transmission buffer
+ * @ifa: Interface holding the transmission buffer
+ * @queue: TLV queue to write (containing internal-format TLVs)
+ *
+ * This function writes a packet to the interface transmission buffer with as
+ * many TLVs from the &queue as will fit in the buffer. It returns the number of
+ * bytes written (NOT counting the packet header). The function is called by
+ * babel_send_queue() and babel_send_unicast() to construct packets for
+ * transmission, and uses per-TLV helper functions to convert the
+ * internal-format TLVs to their wire representations.
+ *
+ * The TLVs in the queue are freed after they are written to the buffer.
+ */
+static int
+babel_write_queue(struct babel_iface *ifa, list *queue)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_write_state state = {};
+
+ if (EMPTY_LIST(*queue))
+ return 0;
+
+ byte *pos = ifa->sk->tbuf;
+ byte *end = pos + ifa->tx_length;
+
+ struct babel_pkt_header *pkt = (void *) pos;
+ pkt->magic = BABEL_MAGIC;
+ pkt->version = BABEL_VERSION;
+ pkt->length = 0;
+ pos += sizeof(struct babel_pkt_header);
+
+ struct babel_msg_node *msg;
+ WALK_LIST_FIRST(msg, *queue)
+ {
+ int len = babel_write_tlv((struct babel_tlv *) pos, &msg->msg, &state, end - pos);
+
+ if (!len)
+ break;
+
+ pos += len;
+ rem_node(NODE msg);
+ sl_free(p->msg_slab, msg);
+ }
+
+ int plen = pos - (byte *) pkt;
+ put_u16(&pkt->length, plen - sizeof(struct babel_pkt_header));
+
+ return plen;
+}
+
+void
+babel_send_queue(void *arg)
+{
+ struct babel_iface *ifa = arg;
+ while ((babel_write_queue(ifa, &ifa->msg_queue) > 0) &&
+ (babel_send_to(ifa, IP6_BABEL_ROUTERS) > 0));
+}
+
+static inline void
+babel_kick_queue(struct babel_iface *ifa)
+{
+ /*
+ * Only schedule send event if there is not already data in the socket buffer.
+ * Otherwise we may overwrite the data already in the buffer.
+ */
+
+ if ((ifa->sk->tpos == ifa->sk->tbuf) && !ev_active(ifa->send_event))
+ ev_schedule(ifa->send_event);
+}
+
+/**
+ * babel_send_unicast - send a single TLV via unicast to a destination
+ * @msg: TLV to send
+ * @ifa: Interface to send via
+ * @dest: Destination of the TLV
+ *
+ * This function is used to send a single TLV via unicast to a designated
+ * receiver. This is used for replying to certain incoming requests, and for
+ * sending unicast requests to refresh routes before they expire.
+ */
+void
+babel_send_unicast(union babel_msg *msg, struct babel_iface *ifa, ip_addr dest)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
+ list queue;
+
+ msgn->msg = *msg;
+ init_list(&queue);
+ add_tail(&queue, NODE msgn);
+ babel_write_queue(ifa, &queue);
+ babel_send_to(ifa, dest);
+
+ /* We could overwrite waiting packet here, we may have to kick TX queue */
+ if (!EMPTY_LIST(ifa->msg_queue))
+ babel_kick_queue(ifa);
+}
+
+/**
+ * babel_enqueue - enqueue a TLV for transmission on an interface
+ * @msg: TLV to enqueue (in internal TLV format)
+ * @ifa: Interface to enqueue to
+ *
+ * This function is called to enqueue a TLV for subsequent transmission on an
+ * interface. The transmission event is triggered whenever a TLV is enqueued;
+ * this ensures that TLVs will be transmitted in a timely manner, but that TLVs
+ * which are enqueued in rapid succession can be transmitted together in one
+ * packet.
+ */
+void
+babel_enqueue(union babel_msg *msg, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
+ msgn->msg = *msg;
+ add_tail(&ifa->msg_queue, NODE msgn);
+ babel_kick_queue(ifa);
+}
+
+/**
+ * babel_process_packet - process incoming data packet
+ * @pkt: Pointer to the packet data
+ * @len: Length of received packet
+ * @saddr: Address of packet sender
+ * @ifa: Interface packet was received on.
+ *
+ * This function is the main processing hook of incoming Babel packets. It
+ * checks that the packet header is well-formed, then processes the TLVs
+ * contained in the packet. This is done in two passes: First all TLVs are
+ * parsed into the internal TLV format. If a TLV parser fails, processing of the
+ * rest of the packet is aborted.
+ *
+ * After the parsing step, the TLV handlers are called for each parsed TLV in
+ * order.
+ */
+static void
+babel_process_packet(struct babel_pkt_header *pkt, int len,
+ ip_addr saddr, struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+ struct babel_tlv *tlv;
+ struct babel_msg_node *msg;
+ list msgs;
+ int res;
+
+ int plen = sizeof(struct babel_pkt_header) + get_u16(&pkt->length);
+ byte *pos;
+ byte *end = (byte *)pkt + plen;
+
+ struct babel_parse_state state = {
+ .proto = p,
+ .ifa = ifa,
+ .saddr = saddr,
+ .next_hop = saddr,
+ };
+
+ if ((pkt->magic != BABEL_MAGIC) || (pkt->version != BABEL_VERSION))
+ {
+ TRACE(D_PACKETS, "Strange packet from %I via %s - magic %d version %d",
+ saddr, ifa->iface->name, pkt->magic, pkt->version);
+ return;
+ }
+
+ if (plen > len)
+ {
+ LOG_PKT("Bad packet from %I via %s - %s (%u)",
+ saddr, ifa->iface->name, "length mismatch", plen);
+ return;
+ }
+
+ TRACE(D_PACKETS, "Packet received from %I via %s",
+ saddr, ifa->iface->name);
+
+ init_list(&msgs);
+
+ /* First pass through the packet TLV by TLV, parsing each into internal data
+ structures. */
+ for (tlv = FIRST_TLV(pkt);
+ (byte *)tlv < end;
+ tlv = NEXT_TLV(tlv))
+ {
+ /* Ugly special case */
+ if (tlv->type == BABEL_TLV_PAD1)
+ continue;
+
+ /* The end of the common TLV header */
+ pos = (byte *)tlv + sizeof(struct babel_tlv);
+ if ((pos > end) || (pos + tlv->length > end))
+ {
+ LOG_PKT("Bad TLV from %I via %s type %d pos %d - framing error",
+ saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
+ break;
+ }
+
+ msg = sl_alloc(p->msg_slab);
+ res = babel_read_tlv(tlv, &msg->msg, &state);
+ if (res == PARSE_SUCCESS)
+ {
+ add_tail(&msgs, NODE msg);
+ }
+ else if (res == PARSE_IGNORE)
+ {
+ DBG("Babel: Ignoring TLV of type %d\n", tlv->type);
+ sl_free(p->msg_slab, msg);
+ }
+ else /* PARSE_ERROR */
+ {
+ LOG_PKT("Bad TLV from %I via %s type %d pos %d - parse error",
+ saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
+ sl_free(p->msg_slab, msg);
+ break;
+ }
+ }
+
+ /* Parsing done, handle all parsed TLVs */
+ WALK_LIST_FIRST(msg, msgs)
+ {
+ if (tlv_data[msg->msg.type].handle_tlv)
+ tlv_data[msg->msg.type].handle_tlv(&msg->msg, ifa);
+ rem_node(NODE msg);
+ sl_free(p->msg_slab, msg);
+ }
+}
+
+static void
+babel_err_hook(sock *sk, int err)
+{
+ struct babel_iface *ifa = sk->data;
+ struct babel_proto *p = ifa->proto;
+
+ log(L_ERR "%s: Socket error on %s: %M", p->p.name, ifa->iface->name, err);
+ /* FIXME: Drop queued TLVs here? */
+}
+
+
+static void
+babel_tx_hook(sock *sk)
+{
+ struct babel_iface *ifa = sk->data;
+
+ DBG("Babel: TX hook called (iface %s, src %I, dst %I)\n",
+ sk->iface->name, sk->saddr, sk->daddr);
+
+ babel_send_queue(ifa);
+}
+
+
+static int
+babel_rx_hook(sock *sk, int len)
+{
+ struct babel_iface *ifa = sk->data;
+ struct babel_proto *p = ifa->proto;
+ const char *err_dsc = NULL;
+ uint err_val = 0;
+
+ if (sk->lifindex != ifa->iface->index)
+ return 1;
+
+ DBG("Babel: RX hook called (iface %s, src %I, dst %I)\n",
+ sk->iface->name, sk->faddr, sk->laddr);
+
+ /* Silently ignore my own packets */
+ if (ipa_equal(ifa->iface->addr->ip, sk->faddr))
+ return 1;
+
+ if (!ipa_is_link_local(sk->faddr))
+ DROP1("wrong src address");
+
+ if (sk->fport != ifa->cf->port)
+ DROP("wrong src port", sk->fport);
+
+ if (len < sizeof(struct babel_pkt_header))
+ DROP("too short", len);
+
+ if (sk->flags & SKF_TRUNCATED)
+ DROP("truncated", len);
+
+ babel_process_packet((struct babel_pkt_header *) sk->rbuf, len, sk->faddr, ifa);
+ return 1;
+
+drop:
+ LOG_PKT("Bad packet from %I via %s - %s (%u)",
+ sk->faddr, sk->iface->name, err_dsc, err_val);
+ return 1;
+}
+
+int
+babel_open_socket(struct babel_iface *ifa)
+{
+ struct babel_proto *p = ifa->proto;
+
+ sock *sk;
+ sk = sk_new(ifa->pool);
+ sk->type = SK_UDP;
+ sk->sport = ifa->cf->port;
+ sk->dport = ifa->cf->port;
+ sk->iface = ifa->iface;
+
+ sk->rx_hook = babel_rx_hook;
+ sk->tx_hook = babel_tx_hook;
+ sk->err_hook = babel_err_hook;
+ sk->data = ifa;
+
+ sk->tos = ifa->cf->tx_tos;
+ sk->priority = ifa->cf->tx_priority;
+ sk->ttl = 1;
+ sk->flags = SKF_LADDR_RX;
+
+ if (sk_open(sk) < 0)
+ goto err;
+
+ if (sk_setup_multicast(sk) < 0)
+ goto err;
+
+ if (sk_join_group(sk, IP6_BABEL_ROUTERS) < 0)
+ goto err;
+
+ ifa->sk = sk;
+ return 1;
+
+err:
+ sk_log_error(sk, p->p.name);
+ rfree(sk);
+ return 0;
+}
projects / thirdparty / bird.git / commitdiff
