Commit cfe34a31 authored by Ondřej Zajíček's avatar Ondřej Zajíček

Implements hostcache and recursive next hops.

Hostcache is a structure for monitoring changes in a routing table that
is used for routes with dynamic/recursive next hops. This is needed for
proper iBGP next hop handling.
parent 824de84d
......@@ -577,10 +577,8 @@ proto_fell_down(struct proto *p)
bzero(&p->stats, sizeof(struct proto_stats));
rt_unlock_table(p->table);
#ifdef CONFIG_PIPE
if (proto_is_pipe(p))
rt_unlock_table(pipe_get_peer_table(p));
#endif
if (p->proto->cleanup)
p->proto->cleanup(p);
proto_rethink_goal(p);
}
......
......@@ -48,6 +48,7 @@ struct protocol {
void (*dump_attrs)(struct rte *); /* Dump protocol-dependent attributes */
int (*start)(struct proto *); /* Start the instance */
int (*shutdown)(struct proto *); /* Stop the instance */
void (*cleanup)(struct proto *); /* Called after shutdown when protocol became hungry/down */
void (*get_status)(struct proto *, byte *buf); /* Get instance status (for `show protocols' command) */
void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
int (*get_attr)(struct eattr *, byte *buf, int buflen); /* ASCIIfy dynamic attribute (returns GA_*) */
......
......@@ -129,14 +129,19 @@ typedef struct rtable {
list hooks; /* List of announcement hooks */
int pipe_busy; /* Pipe loop detection */
int use_count; /* Number of protocols using this table */
struct hostcache *hostcache;
struct rtable_config *config; /* Configuration of this table */
struct config *deleted; /* Table doesn't exist in current configuration,
* delete as soon as use_count becomes 0 and remove
* obstacle from this routing table.
*/
struct event *gc_event; /* Garbage collector event */
struct event *rt_event; /* Routing table event */
int gc_counter; /* Number of operations since last GC */
bird_clock_t gc_time; /* Time of last GC */
byte gc_scheduled; /* GC is scheduled */
byte hcu_scheduled; /* Hostcache update is scheduled */
byte nhu_state; /* Next Hop Update state */
struct fib_iterator nhu_fit; /* Next Hop Update FIB iterator */
} rtable;
typedef struct network {
......@@ -144,6 +149,23 @@ typedef struct network {
struct rte *routes; /* Available routes for this network */
} net;
struct hostcache {
struct fib htable;
list hostentries;
byte update_hostcache;
};
struct hostentry {
struct fib_node fn;
node ln;
unsigned uc; /* Use count */
struct iface *iface; /* Chosen outgoing interface */
ip_addr gw; /* Chosen next hop */
byte dest; /* Chosen route destination type (RTD_...) */
byte pxlen; /* Pxlen from net that matches route */
struct rtable *tab;
};
typedef struct rte {
struct rte *next;
net *net; /* Network this RTE belongs to */
......@@ -207,7 +229,6 @@ void rt_dump(rtable *);
void rt_dump_all(void);
int rt_feed_baby(struct proto *p);
void rt_feed_baby_abort(struct proto *p);
void rt_prune(rtable *tab);
void rt_prune_all(void);
struct rtable_config *rt_new_table(struct symbol *s);
......@@ -248,6 +269,7 @@ typedef struct rta {
u16 hash_key; /* Hash over important fields */
ip_addr gw; /* Next hop */
ip_addr from; /* Advertising router */
struct hostentry *hostentry; /* Hostentry for recursive next-hops */
struct iface *iface; /* Outgoing interface */
struct ea_list *eattrs; /* Extended Attribute chain */
} rta;
......@@ -357,6 +379,25 @@ static inline void rta_free(rta *r) { if (r && !--r->uc) rta__free(r); }
void rta_dump(rta *);
void rta_dump_all(void);
void rta_show(struct cli *, rta *, ea_list *);
void rta_set_recursive_next_hop(rtable *dep, rta *a, rtable *tab, ip_addr *gw);
/*
* rta_set_recursive_next_hop() acquires hostentry from hostcache and
* fills rta->hostentry field. New hostentry has zero use
* count. Cached rta locks its hostentry (increases its use count),
* uncached rta does not lock it. Hostentry with zero use count is
* removed asynchronously during host cache update, therefore it is
* safe to hold such hostentry temorarily. There is no need to hold
* a lock for hostentry->dep table, because that table contains routes
* responsible for that hostentry, and therefore is non-empty if given
* hostentry has non-zero use count. The protocol responsible for routes
* with recursive next hops should also hold a lock for a table governing
* that routes (argument tab to rta_set_recursive_next_hop()).
*/
static inline void rt_lock_hostentry(struct hostentry *he) { if (he) he->uc++; }
static inline void rt_unlock_hostentry(struct hostentry *he) { if (he) he->uc--; }
extern struct protocol *attr_class_to_protocol[EAP_MAX];
......
......@@ -671,6 +671,7 @@ rta_lookup(rta *o)
r = rta_copy(o);
r->hash_key = h;
r->aflags = RTAF_CACHED;
rt_lock_hostentry(r->hostentry);
rta_insert(r);
if (++rta_cache_count > rta_cache_limit)
......@@ -688,6 +689,7 @@ rta__free(rta *a)
if (a->next)
a->next->pprev = a->pprev;
a->aflags = 0; /* Poison the entry */
rt_unlock_hostentry(a->hostentry);
ea_free(a->eattrs);
sl_free(rta_slab, a);
}
......
......@@ -51,6 +51,13 @@ static linpool *rte_update_pool;
static list routing_tables;
static void rt_format_via(rte *e, byte *via);
static void rt_free_hostcache(rtable *tab);
static void rt_notify_hostcache(rtable *tab, net *net);
static void rt_update_hostcache(rtable *tab);
static void rt_next_hop_update(rtable *tab);
static void rt_prune(rtable *tab);
static inline void rt_schedule_gc(rtable *tab);
static void
rte_init(struct fib_node *N)
......@@ -210,7 +217,7 @@ do_rte_announce(struct announce_hook *a, int type UNUSED, net *net, rte *new, rt
* This is a tricky part - we don't know whether route 'old' was
* exported to protocol 'p' or was filtered by the export filter.
* We try tu run the export filter to know this to have a correct
* value in 'old' argument of rt_update (and proper filter value)
* value in 'old' argument of rte_update (and proper filter value)
*
* FIXME - this is broken because 'configure soft' may change
* filters but keep routes. Refeed is expected to be called after
......@@ -327,6 +334,9 @@ rte_announce(rtable *tab, unsigned type, net *net, rte *new, rte *old, ea_list *
new->attrs->proto->stats.pref_routes++;
if (old)
old->attrs->proto->stats.pref_routes--;
if (tab->hostcache)
rt_notify_hostcache(tab, net);
}
WALK_LIST(a, tab->hooks)
......@@ -337,6 +347,7 @@ rte_announce(rtable *tab, unsigned type, net *net, rte *new, rte *old, ea_list *
}
}
static inline int
rte_validate(rte *e)
{
......@@ -469,7 +480,6 @@ rte_recalculate(rtable *table, net *net, struct proto *p, struct proto *src, rte
rte_announce(table, RA_ANY, net, new, old, tmpa);
if (new && rte_better(new, old_best))
{
/* The first case - the new route is cleary optimal, we link it
......@@ -523,7 +533,7 @@ rte_recalculate(rtable *table, net *net, struct proto *p, struct proto *src, rte
}
else if (table->gc_counter++ >= table->config->gc_max_ops &&
table->gc_time + table->config->gc_min_time <= now)
ev_schedule(table->gc_event);
rt_schedule_gc(table);
}
else if (new)
{
......@@ -688,6 +698,21 @@ drop:
rte_update_unlock();
}
/* Independent call to rte_announce(), used from next hop
recalculation, outside of rte_update(). new must be non-NULL */
static inline void
rte_announce_i(rtable *tab, unsigned type, net *n, rte *new, rte *old)
{
struct proto *src;
ea_list *tmpa;
rte_update_lock();
src = new->attrs->proto;
tmpa = src->make_tmp_attrs ? src->make_tmp_attrs(new, rte_update_pool) : NULL;
rte_announce(tab, type, n, new, old, tmpa);
rte_update_unlock();
}
void
rte_discard(rtable *t, rte *old) /* Non-filtered route deletion, used during garbage collection */
{
......@@ -760,14 +785,49 @@ rt_dump_all(void)
rt_dump(t);
}
static inline void
rt_schedule_gc(rtable *tab)
{
if (tab->gc_scheduled)
return;
tab->gc_scheduled = 1;
ev_schedule(tab->rt_event);
}
static inline void
rt_schedule_hcu(rtable *tab)
{
if (tab->hcu_scheduled)
return;
tab->hcu_scheduled = 1;
ev_schedule(tab->rt_event);
}
static inline void
rt_schedule_nhu(rtable *tab)
{
if (tab->nhu_state == 0)
ev_schedule(tab->rt_event);
/* state change 0->1, 2->3 */
tab->nhu_state |= 1;
}
static void
rt_gc(void *tab)
rt_event(void *ptr)
{
rtable *t = tab;
rtable *tab = ptr;
if (tab->hcu_scheduled)
rt_update_hostcache(tab);
if (tab->nhu_state)
rt_next_hop_update(tab);
DBG("Entered routing table garbage collector for %s after %d seconds and %d deletes\n",
t->name, (int)(now - t->gc_time), t->gc_counter);
rt_prune(t);
if (tab->gc_scheduled)
rt_prune(tab);
}
void
......@@ -780,9 +840,9 @@ rt_setup(pool *p, rtable *t, char *name, struct rtable_config *cf)
init_list(&t->hooks);
if (cf)
{
t->gc_event = ev_new(p);
t->gc_event->hook = rt_gc;
t->gc_event->data = t;
t->rt_event = ev_new(p);
t->rt_event->hook = rt_event;
t->rt_event->data = t;
t->gc_time = now;
}
}
......@@ -811,7 +871,7 @@ rt_init(void)
* the routing table and removes all routes belonging to inactive
* protocols and also stale network entries.
*/
void
static void
rt_prune(rtable *tab)
{
struct fib_iterator fit;
......@@ -852,6 +912,7 @@ again:
#endif
tab->gc_counter = 0;
tab->gc_time = now;
tab->gc_scheduled = 0;
}
/**
......@@ -868,6 +929,151 @@ rt_prune_all(void)
rt_prune(t);
}
void
rt_preconfig(struct config *c)
{
struct symbol *s = cf_find_symbol("master");
init_list(&c->tables);
c->master_rtc = rt_new_table(s);
}
/*
* Some functions for handing internal next hop updates
* triggered by rt_schedule_nhu().
*/
static inline int
hostentry_diff(struct hostentry *he, struct iface *iface, ip_addr gw, byte dest)
{
return (he->iface != iface) || !ipa_equal(he->gw, gw) || (he->dest != dest);
}
static inline int
rta_next_hop_outdated(rta *a)
{
struct hostentry *he = a->hostentry;
return he && hostentry_diff(he, a->iface, a->gw, a->dest);
}
static inline void
rta_apply_hostentry(rta *a, struct hostentry *he)
{
a->hostentry = he;
a->iface = he->iface;
a->gw = he->gw;
a->dest = he->dest;
}
static inline rte *
rt_next_hop_update_rte(rtable *tab, rte *old)
{
rta a;
memcpy(&a, old->attrs, sizeof(rta));
rta_apply_hostentry(&a, old->attrs->hostentry);
a.aflags = 0;
rte *e = sl_alloc(rte_slab);
memcpy(e, old, sizeof(rte));
e->attrs = rta_lookup(&a);
return e;
}
static inline int
rt_next_hop_update_net(rtable *tab, net *n)
{
rte **k, *e, *new, *old_best, **new_best;
int count = 0;
int free_old_best = 0;
old_best = n->routes;
if (!old_best)
return 0;
new_best = NULL;
for (k = &n->routes; e = *k; k = &e->next)
{
if (rta_next_hop_outdated(e->attrs))
{
new = rt_next_hop_update_rte(tab, e);
*k = new;
rte_announce_i(tab, RA_ANY, n, new, e);
rte_trace_in(D_ROUTES, new->sender, new, "updated");
if (e != old_best)
rte_free_quick(e);
else /* Freeing of the old best rte is postponed */
free_old_best = 1;
e = new;
count++;
}
if (!new_best || rte_better(e, *new_best))
new_best = k;
}
/* Relink the new best route to the first position */
new = *new_best;
if (new != n->routes)
{
*new_best = new->next;
new->next = n->routes;
n->routes = new;
}
/* Announce the new best route */
if (new != old_best)
{
rte_announce_i(tab, RA_OPTIMAL, n, new, old_best);
rte_trace_in(D_ROUTES, new->sender, new, "updated [best]");
}
if (free_old_best)
rte_free_quick(old_best);
return count;
}
static void
rt_next_hop_update(rtable *tab)
{
struct fib_iterator *fit = &tab->nhu_fit;
int max_feed = 32;
if (tab->nhu_state == 0)
return;
if (tab->nhu_state == 1)
{
FIB_ITERATE_INIT(fit, &tab->fib);
tab->nhu_state = 2;
}
FIB_ITERATE_START(&tab->fib, fit, fn)
{
if (max_feed <= 0)
{
FIB_ITERATE_PUT(fit, fn);
ev_schedule(tab->rt_event);
return;
}
max_feed -= rt_next_hop_update_net(tab, (net *) fn);
}
FIB_ITERATE_END(fn);
/* state change 2->0, 3->1 */
tab->nhu_state &= 1;
if (tab->nhu_state > 0)
ev_schedule(tab->rt_event);
}
struct rtable_config *
rt_new_table(struct symbol *s)
{
......@@ -881,15 +1087,6 @@ rt_new_table(struct symbol *s)
return c;
}
void
rt_preconfig(struct config *c)
{
struct symbol *s = cf_find_symbol("master");
init_list(&c->tables);
c->master_rtc = rt_new_table(s);
}
/**
* rt_lock_table - lock a routing table
* @r: routing table to be locked
......@@ -919,8 +1116,11 @@ rt_unlock_table(rtable *r)
{
struct config *conf = r->deleted;
DBG("Deleting routing table %s\n", r->name);
if (r->hostcache)
rt_free_hostcache(r);
rem_node(&r->n);
fib_free(&r->fib);
rfree(r->rt_event);
mb_free(r);
config_del_obstacle(conf);
}
......@@ -1087,6 +1287,178 @@ rt_feed_baby_abort(struct proto *p)
}
}
static void
hostentry_init(struct fib_node *fn)
{
((struct hostentry *) fn)->uc = 0;
((struct hostentry *) fn)->tab = NULL;
}
static void
rt_init_hostcache(rtable *tab)
{
struct hostcache *hc = mb_allocz(rt_table_pool, sizeof(struct hostcache));
init_list(&hc->hostentries);
fib_init(&hc->htable, rt_table_pool, sizeof(struct hostentry), 0, hostentry_init);
tab->hostcache = hc;
}
static void
rt_free_hostcache(rtable *tab)
{
struct hostcache *hc = tab->hostcache;
node *n;
WALK_LIST(n, hc->hostentries)
{
struct hostentry *he = SKIP_BACK(struct hostentry, ln, n);
if (he->uc)
log(L_ERR "Hostcache is not empty in table %s", tab->name);
}
fib_free(&hc->htable);
mb_free(hc);
}
static void
rt_notify_hostcache(rtable *tab, net *net)
{
struct hostcache *hc = tab->hostcache;
if (tab->hcu_scheduled)
return;
node *n;
WALK_LIST(n, hc->hostentries)
{
struct hostentry *he = SKIP_BACK(struct hostentry, ln, n);
if (ipa_in_net(he->fn.prefix, net->n.prefix, net->n.pxlen) &&
(he->pxlen <= net->n.pxlen))
{
rt_schedule_hcu(tab);
return;
}
}
}
static int
if_local_addr(ip_addr a, struct iface *i)
{
struct ifa *b;
WALK_LIST(b, i->addrs)
if (ipa_equal(a, b->ip))
return 1;
return 0;
}
static int
rt_update_hostentry(rtable *tab, struct hostentry *he)
{
struct iface *old_iface = he->iface;
ip_addr old_gw = he->gw;
byte old_dest = he->dest;
net *n = fib_route(&tab->fib, he->fn.prefix, MAX_PREFIX_LENGTH);
if (n && n->routes)
{
rta *a = n->routes->attrs;
if (a->dest == RTD_DEVICE)
{
if (if_local_addr(he->fn.prefix, a->iface))
{
/* The host address is a local address, this is not valid */
log(L_WARN "Next hop address %I is a local address of iface %s",
he->fn.prefix, a->iface->name);
he->iface = NULL;
he->gw = IPA_NONE;
he->dest = RTD_UNREACHABLE;
}
else
{
/* The host is directly reachable, us it as a gateway */
he->iface = a->iface;
he->gw = he->fn.prefix;
he->dest = RTD_ROUTER;
}
}
else
{
/* The host is reachable through some route entry */
he->iface = a->iface;
he->gw = a->gw;
he->dest = a->dest;
}
he->pxlen = n->n.pxlen;
}
else
{
/* The host is unreachable */
he->iface = NULL;
he->gw = IPA_NONE;
he->dest = RTD_UNREACHABLE;
he->pxlen = 0;
}
return hostentry_diff(he, old_iface, old_gw, old_dest);
}
static void
rt_update_hostcache(rtable *tab)
{
struct hostcache *hc = tab->hostcache;
struct hostentry *he;
node *n, *x;
WALK_LIST_DELSAFE(n, x, hc->hostentries)
{
he = SKIP_BACK(struct hostentry, ln, n);
if (!he->uc)
{
/* Delete a hostentry */
rem_node(&he->ln);
fib_delete(&hc->htable, he);
continue;
}
if (rt_update_hostentry(tab, he))
rt_schedule_nhu(he->tab);
}
tab->hcu_scheduled = 0;
}
static struct hostentry *
rt_find_hostentry(rtable *tab, ip_addr *a, rtable *dep)
{
struct hostentry *he;
if (!tab->hostcache)
rt_init_hostcache(tab);
he = fib_get(&tab->hostcache->htable, a, MAX_PREFIX_LENGTH);
if (!he->tab)
{
/* New entry */
add_tail(&tab->hostcache->hostentries, &he->ln);
he->tab = dep;
rt_update_hostentry(tab, he);
}
return he;
}
void
rta_set_recursive_next_hop(rtable *dep, rta *a, rtable *tab, ip_addr *gw)
{
rta_apply_hostentry(a, rt_find_hostentry(tab, gw, dep));
}
/*
* CLI commands
*/
......
......@@ -1265,15 +1265,13 @@ bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct lin
ea_list *ea;
struct adata *ad;
bzero(a, sizeof(rta));
a->proto = &bgp->p;
a->source = RTS_BGP;
a->scope = SCOPE_UNIVERSE;
a->cast = RTC_UNICAST;
a->dest = RTD_ROUTER;
a->flags = 0;
a->aflags = 0;
/* a->dest = RTD_ROUTER; -- set in bgp_set_next_hop() */
a->from = bgp->cf->remote_ip;
a->eattrs = NULL;
/* Parse the attributes */
bzero(seen, sizeof(seen));
......
......@@ -786,6 +786,8 @@ bgp_start(struct proto *P)
p->incoming_conn.state = BS_IDLE;
p->neigh = NULL;
rt_lock_table(p->igp_table);
p->event = ev_new(p->p.pool);
p->event->hook = bgp_decision;
p->event->data = p;
......@@ -837,6 +839,19 @@ bgp_shutdown(struct proto *P)
return p->p.proto_state;
}
static void
bgp_cleanup(struct proto *P)
{
struct bgp_proto *p = (struct bgp_proto *) P;
rt_unlock_table(p->igp_table);
}
static rtable *
get_igp_table(struct bgp_config *cf)
{
return cf->igp_table ? cf->igp_table->table : cf->c.table->table;
}
static struct proto *
bgp_init(struct proto_config *C)
{
......@@ -854,6 +869,7 @@ bgp_init(struct proto_config *C)
p->local_as = c->local_as;
p->remote_as = c->remote_as;
p->is_internal = (c->local_as == c->remote_as);
p->igp_table = get_igp_table(c);
return P;
}
......@@ -1065,7 +1081,8 @@ bgp_reconfigure(struct proto *P, struct proto_config *C)
// password item is last and must be checked separately
OFFSETOF(struct bgp_config, password) - sizeof(struct proto_config))
&& ((!old->password && !new->password)
|| (old->password && new->password && !strcmp(old->password, new->password)));
|| (old->password && new->password && !strcmp(old->password, new->password)))
&& (get_igp_table(old) == get_igp_table(new));
/* We should update our copy of configuration ptr as old configuration will be freed */
if (same)
......@@ -1081,6 +1098,7 @@ struct protocol proto_bgp = {
init: bgp_init,
start: bgp_start,
shutdown: bgp_shutdown,
cleanup: bgp_cleanup,
reconfigure: bgp_reconfigure,
get_status: bgp_get_status,
get_attr: bgp_get_attr,
......
......@@ -47,6 +47,7 @@ struct bgp_config {
unsigned error_delay_time_max;
unsigned disable_after_error; /* Disable the protocol when error is detected */
char *password; /* Password used for MD5 authentication */
struct rtable_config *igp_table; /* Table used for recursive next hop lookups */
};
#define MLL_SELF 1
......@@ -92,6 +93,7 @@ struct bgp_proto {
struct neighbor *neigh; /* Neighbor entry corresponding to next_hop */
ip_addr local_addr; /* Address of the local end of the link to next_hop */
ip_addr source_addr; /* Address used as advertised next hop, usually local_addr */
rtable *igp_table; /* Table used for recursive next hop lookups */
struct event *event; /* Event for respawning and shutting process */
struct timer *startup_timer; /* Timer used to delay protocol startup due to previous errors (startup_delay) */
struct bgp_bucket **bucket_hash; /* Hash table of attribute buckets */
......
......@@ -24,7 +24,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
PASSWORD, RR, RS, CLIENT, CLUSTER, ID, AS4, ADVERTISE, IPV4,
CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER, MISSING, LLADDR,
DROP, IGNORE, ROUTE, REFRESH, INTERPRET, COMMUNITIES,
BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST)
BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP, TABLE)
CF_GRAMMAR
......@@ -89,6 +89,7 @@ bgp_proto:
| bgp_proto ROUTE LIMIT expr ';' { BGP_CFG->route_limit = $4; }
| bgp_proto PASSIVE bool ';' { BGP_CFG->passive = $3; }
| bgp_proto INTERPRET COMMUNITIES bool ';' { BGP_CFG->interpret_communities = $4; }
| bgp_proto IGP TABLE rtable ';' { BGP_CFG->igp_table = $4; }
;
CF_ADDTO(dynamic_attr, BGP_ORIGIN
......
......@@ -802,26 +802,26 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)