Commit e2dc2f30 authored by Martin Mareš's avatar Martin Mareš

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.
parent 9e0e485e
/*
* BIRD Internet Routing Daemon -- Routing Table
*
* (c) 1998 Martin Mares <mj@ucw.cz>
* (c) 1998--1999 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
......@@ -150,6 +150,8 @@ typedef struct rte {
} u;
} rte;
#define REF_COW 1 /* Copy this rte on write */
extern rtable master_table;
void rt_init(void);
......@@ -162,6 +164,8 @@ void rte_update(net *net, struct proto *p, rte *new);
void rte_discard(rte *old);
void rte_dump(rte *);
void rte_free(rte *);
rte *rte_do_cow(rte *);
static inline rte * rte_cow(rte *r) { return (r->flags & REF_COW) ? rte_do_cow(r) : r; }
void rt_dump(rtable *);
void rt_dump_all(void);
void rt_feed_baby(struct proto *p);
......
......@@ -19,6 +19,7 @@
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
......@@ -95,6 +96,17 @@ rte_get_temp(rta *a)
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)
{
......@@ -114,21 +126,42 @@ rte_better(rte *new, rte *old)
}
static inline void
do_rte_announce(struct proto *p, net *net, rte *new, rte *old)
do_rte_announce(struct proto *p, net *net, rte *new, rte *old, ea_list *tmpa)
{
if (p->out_filter)
rte *new0 = new;
rte *old0 = old;
if (new)
{
if (old && f_run(p->out_filter, old, NULL) != F_ACCEPT)
old = NULL;
if (new && f_run(p->out_filter, new, NULL) != F_ACCEPT)
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);
}
void
rte_announce(net *net, rte *new, rte *old)
static void
rte_announce(net *net, rte *new, rte *old, ea_list *tmpa)
{
struct proto *p;
......@@ -136,7 +169,7 @@ rte_announce(net *net, rte *new, rte *old)
{
ASSERT(p->core_state == FS_HAPPY);
if (p->rt_notify)
do_rte_announce(p, net, new, old);
do_rte_announce(p, net, new, old, tmpa);
}
}
......@@ -155,7 +188,12 @@ rt_feed_baby(struct proto *p)
net *n = (net *) fn;
rte *e;
for(e=n->routes; e; e=e->next)
do_rte_announce(p, n, e, NULL);
{
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;
......@@ -209,24 +247,13 @@ rte_free_quick(rte *e)
sl_free(rte_slab, e);
}
void
rte_update(net *net, struct proto *p, rte *new)
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;
if (new)
{
if (!rte_validate(new) || p->in_filter && f_run(p->in_filter, new, NULL) != F_ACCEPT)
{
rte_free(new);
return;
}
if (!(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)
{
......@@ -240,7 +267,7 @@ rte_update(net *net, struct proto *p, rte *new)
if (new && rte_better(new, old_best)) /* It's a new optimal route => announce and relink it */
{
rte_announce(net, new, old_best);
rte_announce(net, new, old_best, tmpa);
new->next = net->routes;
net->routes = new;
}
......@@ -252,7 +279,7 @@ rte_update(net *net, struct proto *p, rte *new)
for(s=net->routes; s; s=s->next)
if (rte_better(s, r))
r = s;
rte_announce(net, r, old_best);
rte_announce(net, r, old_best, tmpa);
if (r) /* Re-link the new optimal route */
{
k = &net->routes;
......@@ -291,10 +318,60 @@ rte_update(net *net, struct proto *p, rte *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(old->net, old->attrs->proto, NULL);
rte_update_lock();
rte_recalculate(old->net, old->attrs->proto, NULL, NULL);
rte_update_unlock();
}
void
......@@ -357,6 +434,7 @@ 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;
......
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