bird/nest/rt-table.c
Martin Mares 5996da6a1d Implemented garbage collection of routing tables to delete orphaned network
nodes having no routes attached. Such cleanup must be done from event handler
since most functions manipulating the routing tables expect network entries
won't disappear from under their hands and it's also probably faster when
done asynchronously.
1999-02-13 21:29:01 +00:00

349 lines
6.5 KiB
C

/*
* BIRD -- Routing Table
*
* (c) 1998 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <string.h>
#define LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "lib/resource.h"
#include "lib/event.h"
rtable master_table;
static slab *rte_slab;
#define RT_GC_MIN_TIME 5 /* FIXME: Make configurable */
#define RT_GC_MIN_COUNT 100
static pool *rt_table_pool;
static event *rt_gc_event;
static bird_clock_t rt_last_gc;
static int rt_gc_counter;
static void
rte_init(struct fib_node *N)
{
net *n = (net *) N;
N->flags = 0;
n->routes = NULL;
}
void
rt_setup(rtable *t, char *name)
{
bzero(t, sizeof(*t));
fib_init(&t->fib, &root_pool, sizeof(rte), 0, rte_init);
t->name = name;
}
net *
net_find(rtable *tab, unsigned tos, ip_addr mask, unsigned len)
{
while (tab && tab->tos != tos)
tab = tab->sibling;
if (!tab)
return NULL;
return (net *) fib_find(&tab->fib, &mask, len);
}
net *
net_get(rtable *tab, unsigned tos, ip_addr mask, unsigned len)
{
rtable *t = tab;
while (t && t->tos != tos)
t = t->sibling;
if (!t)
{
while (tab->sibling)
tab = tab->sibling;
t = mb_alloc(&root_pool, sizeof(rtable));
rt_setup(t, NULL);
tab->sibling = t;
t->tos = tos;
}
return (net *) fib_get(&t->fib, &mask, len);
}
rte *
rte_find(net *net, struct proto *p)
{
rte *e = net->routes;
while (e && e->attrs->proto != p)
e = e->next;
return e;
}
rte *
rte_get_temp(rta *a)
{
rte *e = sl_alloc(rte_slab);
e->attrs = a;
e->flags = 0;
e->pref = a->proto->preference;
return e;
}
static int /* Actually better or at least as good as */
rte_better(rte *new, rte *old)
{
int (*better)(rte *, rte *);
if (!old)
return 1;
if (new->pref > old->pref)
return 1;
if (new->pref < old->pref)
return 0;
if (new->attrs->proto != old->attrs->proto)
{
/* FIXME!!! */
bug("Different protocols, but identical preferences => oops");
}
if (better = new->attrs->proto->rte_better)
return better(new, old);
return 0;
}
void
rte_announce(net *net, rte *new, rte *old)
{
struct proto *p;
WALK_LIST(p, proto_list)
{
ASSERT(p->core_state == FS_HAPPY);
if (p->rt_notify)
p->rt_notify(p, net, new, old);
}
}
void
rt_feed_baby(struct proto *p)
{
rtable *t = &master_table;
if (!p->rt_notify)
return;
debug("Announcing routes to new protocol %s\n", p->name);
while (t)
{
FIB_WALK(&t->fib, fn)
{
net *n = (net *) fn;
rte *e;
for(e=n->routes; e; e=e->next)
p->rt_notify(p, n, e, NULL);
}
FIB_WALK_END;
t = t->sibling;
}
}
void
rte_free(rte *e)
{
if (e->attrs->aflags & RTAF_CACHED)
rta_free(e->attrs);
sl_free(rte_slab, e);
}
static inline void
rte_free_quick(rte *e)
{
rta_free(e->attrs);
sl_free(rte_slab, e);
}
void
rte_update(net *net, struct proto *p, rte *new)
{
rte *old_best = net->routes;
rte *old = NULL;
rte **k, *r, *s;
if (new && !(new->attrs->aflags & RTAF_CACHED)) /* Need to copy attributes */
new->attrs = rta_lookup(new->attrs);
k = &net->routes; /* Find and remove original route from the same protocol */
while (old = *k)
{
if (old->attrs->proto == p)
{
*k = old->next;
break;
}
k = &old->next;
}
if (new && rte_better(new, old_best)) /* It's a new optimal route => announce and relink it */
{
rte_announce(net, new, old_best);
new->next = net->routes;
net->routes = new;
}
else
{
if (old == old_best) /* It has _replaced_ the old optimal route */
{
r = new; /* Find new optimal route and announce it */
for(s=net->routes; s; s=s->next)
if (rte_better(s, r))
r = s;
rte_announce(net, r, old_best);
if (r) /* Re-link the new optimal route */
{
k = &net->routes;
while (s = *k)
{
if (s == r)
{
*k = r->next;
break;
}
k = &s->next;
}
r->next = net->routes;
net->routes = r;
if (!r && rt_gc_counter++ >= RT_GC_MIN_COUNT && rt_last_gc + RT_GC_MIN_TIME <= now)
ev_schedule(rt_gc_event);
}
}
if (new) /* Link in the new non-optimal route */
{
new->next = old_best->next;
old_best->next = new;
}
}
if (old)
{
if (p->rte_remove)
p->rte_remove(net, old);
rte_free_quick(old);
}
if (new)
{
new->lastmod = now;
if (p->rte_insert)
p->rte_insert(net, new);
}
}
void
rte_discard(rte *old) /* Non-filtered route deletion, used during garbage collection */
{
rte_update(old->net, old->attrs->proto, NULL);
}
void
rte_dump(rte *e)
{
net *n = e->net;
if (n)
debug("%1I/%2d ", n->n.prefix, n->n.pxlen);
else
debug("??? ");
debug("PF=%02x pref=%d lm=%d ", e->pflags, e->pref, now-e->lastmod);
rta_dump(e->attrs);
if (e->flags & REF_CHOSEN)
debug(" [*]");
debug("\n");
}
void
rt_dump(rtable *t)
{
rte *e;
net *n;
debug("Dump of routing table <%s>\n", t->name);
while (t)
{
debug("Routes for TOS %02x:\n", t->tos);
#ifdef DEBUGGING
fib_check(&t->fib);
#endif
FIB_WALK(&t->fib, fn)
{
n = (net *) fn;
for(e=n->routes; e; e=e->next)
rte_dump(e);
}
FIB_WALK_END;
t = t->sibling;
}
debug("\n");
}
void
rt_dump_all(void)
{
rt_dump(&master_table);
}
static void
rt_gc(void *unused)
{
DBG("Entered routing table garbage collector after %d seconds and %d deletes\n", (int)(now - rt_last_gc), rt_gc_counter);
rt_prune(&master_table);
rt_last_gc = now;
rt_gc_counter = 0;
}
void
rt_init(void)
{
rta_init();
rt_table_pool = rp_new(&root_pool, "Routing tables");
rt_setup(&master_table, "master");
rte_slab = sl_new(rt_table_pool, sizeof(rte));
rt_last_gc = now;
rt_gc_event = ev_new(rt_table_pool);
rt_gc_event->hook = rt_gc;
}
void
rt_prune(rtable *tab)
{
struct fib_iterator fit;
int rcnt = 0, rdel = 0, ncnt = 0, ndel = 0;
DBG("Pruning route table %s\n", tab->name);
while (tab)
{
FIB_ITERATE_INIT(&fit, &tab->fib);
again:
FIB_ITERATE_START(&tab->fib, &fit, f)
{
net *n = (net *) f;
rte *e;
ncnt++;
for (e=n->routes; e; e=e->next, rcnt++)
if (e->attrs->proto->core_state != FS_HAPPY)
{
rte_discard(e);
rdel++;
}
if (!n->routes) /* Orphaned FIB entry? */
{
FIB_ITERATE_PUT(&fit, f);
fib_delete(&tab->fib, f);
ndel++;
goto again;
}
}
FIB_ITERATE_END(f);
tab = tab->sibling;
}
DBG("Pruned %d of %d routes and %d of %d networks\n", rcnt, rdel, ncnt, ndel);
}