bird/nest/rt-table.c
Martin Mares e2dc2f30ef Routing table core changes to support full route filtering:
o  Introduced rte_cow() which should be used for copying on write the
   rte's in filters. Each rte now carries a flag saying whether it's
   a real route (possessing table linkage and other insignia) or a local
   copy. This function can be expected to be fast since its fast-path
   is inlined.
o  Introduced rte_update_pool which is a linear memory pool used for
   all temporary data during rte_update. You should not reference it directly
   -- instead use a pool pointer passed to all related functions.
o  Split rte_update to three functions:

	rte_update	The front end: handles all checking, inbound
			filtering and calls rte_recalculate() for the
			final version of the route.
	rte_recalculate	Update the table according to already filtered route.
	rte_announce	Announce routing table changes to all protocols,
			passing them through export filters and so on.

   The interface has _not_ changed -- still call rte_update() and it will
   do the rest for you automagically.
o  Use new filtering semantics to be explained in a separate mail.
1999-04-05 20:25:03 +00:00

481 lines
9.9 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"
#include "filter/filter.h"
rtable master_table;
static slab *rte_slab;
static linpool *rte_update_pool;
#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(pool *p, rtable *t, char *name)
{
bzero(t, sizeof(*t));
fib_init(&t->fib, p, 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(&root_pool, t, NULL); /* FIXME: Either delete all the TOS logic or use the right pool */
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;
}
rte *
rte_do_cow(rte *r)
{
rte *e = sl_alloc(rte_slab);
memcpy(e, r, sizeof(rte));
e->attrs = rta_clone(r->attrs);
e->flags = 0;
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->proto != old->attrs->proto->proto)
bug("Different protocols, but identical preferences => oops"); /* FIXME */
if (better = new->attrs->proto->rte_better)
return better(new, old);
return 0;
}
static inline void
do_rte_announce(struct proto *p, net *net, rte *new, rte *old, ea_list *tmpa)
{
rte *new0 = new;
rte *old0 = old;
if (new)
{
int ok = p->import_control ? p->import_control(p, &new, &tmpa, rte_update_pool) : 0;
if (ok < 0 ||
(!ok && (p->out_filter == FILTER_REJECT ||
p->out_filter && f_run(p->out_filter, &new, &tmpa, rte_update_pool) > F_MODIFY)
)
)
new = NULL;
}
if (old && p->out_filter)
{
/* FIXME: Do we really need to filter old routes? */
if (p->out_filter == FILTER_REJECT)
old = NULL;
else
{
ea_list *tmpb = p->make_tmp_attrs ? p->make_tmp_attrs(old, rte_update_pool) : NULL;
if (f_run(p->out_filter, &old, &tmpb, rte_update_pool) > F_MODIFY)
old = NULL;
}
}
if (new || old)
p->rt_notify(p, net, new, old);
if (new && new != new0) /* Discard temporary rte's */
rte_free(new);
if (old && old != old0)
rte_free(old);
}
static void
rte_announce(net *net, rte *new, rte *old, ea_list *tmpa)
{
struct proto *p;
WALK_LIST(p, proto_list)
{
ASSERT(p->core_state == FS_HAPPY);
if (p->rt_notify)
do_rte_announce(p, net, new, old, tmpa);
}
}
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)
{
struct proto *q = e->attrs->proto;
ea_list *tmpa = q->make_tmp_attrs ? q->make_tmp_attrs(e, rte_update_pool) : NULL;
do_rte_announce(p, n, e, NULL, tmpa);
lp_flush(rte_update_pool);
}
}
FIB_WALK_END;
t = t->sibling;
}
}
static inline int
rte_validate(rte *e)
{
int c;
net *n = e->net;
ASSERT(!ipa_nonzero(ipa_and(n->n.prefix, ipa_not(ipa_mkmask(n->n.pxlen)))));
if (n->n.pxlen)
{
c = ipa_classify(n->n.prefix);
if (c < 0 || !(c & IADDR_HOST))
{
if (!ipa_nonzero(n->n.prefix) && n->n.pxlen <= 1)
return 1; /* Default route and half-default route is OK */
log(L_WARN "Ignoring bogus route %I/%d received from %I via %s",
n->n.prefix, n->n.pxlen, e->attrs->from, e->attrs->proto->name);
return 0;
}
if ((c & IADDR_SCOPE_MASK) == SCOPE_HOST)
{
int s = e->attrs->source;
if (s != RTS_STATIC && s != RTS_DEVICE && s != RTS_STATIC_DEVICE)
{
log(L_WARN "Ignoring host scope route %I/%d received from %I via %s",
n->n.prefix, n->n.pxlen, e->attrs->from, e->attrs->proto->name);
return 0;
}
}
}
return 1;
}
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);
}
static void
rte_recalculate(net *net, struct proto *p, rte *new, ea_list *tmpa)
{
rte *old_best = net->routes;
rte *old = NULL;
rte **k, *r, *s;
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, tmpa);
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, tmpa);
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);
}
}
static int rte_update_nest_cnt; /* Nesting counter to allow recursive updates */
static inline void
rte_update_lock(void)
{
rte_update_nest_cnt++;
}
static inline void
rte_update_unlock(void)
{
if (!--rte_update_nest_cnt)
lp_flush(rte_update_pool);
}
void
rte_update(net *net, struct proto *p, rte *new)
{
ea_list *tmpa = NULL;
rte_update_lock();
if (new)
{
if (!rte_validate(new) || p->in_filter == FILTER_REJECT)
goto drop;
if (p->make_tmp_attrs)
tmpa = p->make_tmp_attrs(new, rte_update_pool);
if (p->in_filter)
{
int fr = f_run(p->in_filter, &new, &tmpa, rte_update_pool);
if (fr > F_MODIFY)
goto drop;
if (fr == F_MODIFY && p->store_tmp_attrs)
p->store_tmp_attrs(new, tmpa);
}
if (!(new->attrs->aflags & RTAF_CACHED)) /* Need to copy attributes */
new->attrs = rta_lookup(new->attrs);
new->flags |= REF_COW;
}
rte_recalculate(net, p, new, tmpa);
rte_update_unlock();
return;
drop:
rte_free(new);
rte_update_unlock();
}
void
rte_discard(rte *old) /* Non-filtered route deletion, used during garbage collection */
{
rte_update_lock();
rte_recalculate(old->net, old->attrs->proto, NULL, NULL);
rte_update_unlock();
}
void
rte_dump(rte *e)
{
net *n = e->net;
if (n)
debug("%1I/%2d ", n->n.prefix, n->n.pxlen);
else
debug("??? ");
debug("KF=%02x PF=%02x pref=%d lm=%d ", n->n.flags, e->pflags, e->pref, now-e->lastmod);
rta_dump(e->attrs);
if (e->attrs->proto->proto->dump_attrs)
e->attrs->proto->proto->dump_attrs(e);
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");
rte_update_pool = lp_new(rt_table_pool, 4080);
rt_setup(rt_table_pool, &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++;
rescan:
for (e=n->routes; e; e=e->next, rcnt++)
if (e->attrs->proto->core_state != FS_HAPPY)
{
rte_discard(e);
rdel++;
goto rescan;
}
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);
}