Commit b7d7599c authored by Ondřej Zajíček's avatar Ondřej Zajíček
Browse files

BGP: implement Adj-RIB-Out

The patch implements optional internal export table to a channel and
hooks it to BGP so it can be used as Adj-RIB-Out. When enabled, all
exported (post-filtered) routes are stored there. An export table can be
examined using e.g. 'show route export table bgp1.ipv4'.
parent dfe63ed8
......@@ -2705,6 +2705,16 @@ be used in explicit configuration.
be examined later by <cf/show route/, and can be used to reconfigure
import filters without full route refresh. Default: off.
<tag><label id="bgp-export-table">export table <m/switch/</tag>
A BGP export table contains all routes sent to given BGP neighbor, after
application of export filters. It is also called <em/Adj-RIB-Out/ in BGP
terminology. BIRD BGP by default operates without export tables, in
which case routes from master table are just processed by export filters
and then announced by BGP. Enabling <cf/export table/ allows to store
routes after export filter processing, so they can be examined later by
<cf/show route/, and can be used to eliminate unnecessary updates or
withdraws. Default: off.
<tag><label id="bgp-secondary">secondary <m/switch/</tag>
Usually, if an export filter rejects a selected route, no other route is
propagated for that network. This option allows to try the next route in
......
......@@ -567,6 +567,17 @@ r_args:
rt_show_add_table($$, c->in_table);
$$->tables_defined_by = RSD_TDB_DIRECT;
}
| r_args EXPORT TABLE CF_SYM_KNOWN '.' r_args_channel {
cf_assert_symbol($4, SYM_PROTO);
$$ = $1;
struct proto_config *cf = $4->proto;
if (!cf->proto) cf_error("%s is not a protocol", $4->name);
struct channel *c = proto_find_channel_by_name(cf->proto, $6);
if (!c) cf_error("Channel %s.%s not found", $4->name, $6);
if (!c->out_table) cf_error("No export table in channel %s.%s", $4->name, $6);
rt_show_add_table($$, c->out_table);
$$->tables_defined_by = RSD_TDB_DIRECT;
}
| r_args FILTER filter {
$$ = $1;
if ($$->filter != FILTER_ACCEPT) cf_error("Filter specified twice");
......
......@@ -317,6 +317,13 @@ channel_reset_import(struct channel *c)
rt_prune_sync(c->in_table, 1);
}
static void
channel_reset_export(struct channel *c)
{
/* Just free the routes */
rt_prune_sync(c->out_table, 1);
}
/* Called by protocol to activate in_table */
void
channel_setup_in_table(struct channel *c)
......@@ -331,6 +338,18 @@ channel_setup_in_table(struct channel *c)
c->reload_event = ev_new_init(c->proto->pool, channel_reload_loop, c);
}
/* Called by protocol to activate out_table */
void
channel_setup_out_table(struct channel *c)
{
struct rtable_config *cf = mb_allocz(c->proto->pool, sizeof(struct rtable_config));
cf->name = "export";
cf->addr_type = c->net_type;
c->out_table = mb_allocz(c->proto->pool, sizeof(struct rtable));
rt_setup(c->proto->pool, c->out_table, cf);
}
static void
channel_do_start(struct channel *c)
......@@ -376,6 +395,7 @@ channel_do_down(struct channel *c)
c->in_table = NULL;
c->reload_event = NULL;
c->out_table = NULL;
CALL(c->channel->cleanup, c);
......@@ -411,6 +431,9 @@ channel_set_state(struct channel *c, uint state)
if (c->in_table && (cs == CS_UP))
channel_reset_import(c);
if (c->out_table && (cs == CS_UP))
channel_reset_export(c);
break;
case CS_UP:
......@@ -433,6 +456,9 @@ channel_set_state(struct channel *c, uint state)
if (c->in_table && (cs == CS_UP))
channel_reset_import(c);
if (c->out_table && (cs == CS_UP))
channel_reset_export(c);
channel_do_flush(c);
break;
......
......@@ -539,6 +539,8 @@ struct channel {
struct event *reload_event; /* Event responsible for reloading from in_table */
struct fib_iterator reload_fit; /* Iterator in in_table used during reloading */
u8 reload_active; /* Iterator reload_fit is linked */
struct rtable *out_table; /* Internal table for exported routes */
};
......@@ -607,6 +609,7 @@ int proto_configure_channel(struct proto *p, struct channel **c, struct channel_
void channel_set_state(struct channel *c, uint state);
void channel_setup_in_table(struct channel *c);
void channel_setup_out_table(struct channel *c);
void channel_schedule_reload(struct channel *c);
static inline void channel_init(struct channel *c) { channel_set_state(c, CS_START); }
......
......@@ -320,6 +320,7 @@ int rte_update_in(struct channel *c, const net_addr *n, rte *new, struct rte_src
int rt_reload_channel(struct channel *c);
void rt_reload_channel_abort(struct channel *c);
void rt_prune_sync(rtable *t, int all);
int rte_update_out(struct channel *c, const net_addr *n, rte *new, rte *old0, int refeed);
struct rtable_config *rt_new_table(struct symbol *s, uint addr_type);
......
......@@ -633,7 +633,6 @@ do_rt_notify(struct channel *c, net *net, rte *new, rte *old, int refeed)
struct proto *p = c->proto;
struct proto_stats *stats = &c->stats;
/*
* First, apply export limit.
*
......@@ -679,6 +678,8 @@ do_rt_notify(struct channel *c, net *net, rte *new, rte *old, int refeed)
}
}
if (c->out_table && !rte_update_out(c, net->n.addr, new, old, refeed))
return;
if (new)
stats->exp_updates_accepted++;
......@@ -2507,6 +2508,10 @@ rt_feed_channel_abort(struct channel *c)
}
/*
* Import table
*/
int
rte_update_in(struct channel *c, const net_addr *n, rte *new, struct rte_src *src)
{
......@@ -2668,6 +2673,89 @@ rt_prune_sync(rtable *t, int all)
}
/*
* Export table
*/
int
rte_update_out(struct channel *c, const net_addr *n, rte *new, rte *old0, int refeed)
{
struct rtable *tab = c->out_table;
struct rte_src *src;
rte *old, **pos;
net *net;
if (new)
{
net = net_get(tab, n);
src = new->attrs->src;
}
else
{
net = net_find(tab, n);
src = old0->attrs->src;
if (!net)
goto drop_withdraw;
}
/* Find the old rte */
for (pos = &net->routes; old = *pos; pos = &old->next)
if (old->attrs->src == src)
{
if (new && rte_same(old, new))
{
/* REF_STALE / REF_DISCARD not used in export table */
/*
if (old->flags & (REF_STALE | REF_DISCARD | REF_MODIFY))
{
old->flags &= ~(REF_STALE | REF_DISCARD | REF_MODIFY);
return 1;
}
*/
goto drop_update;
}
/* Remove the old rte */
*pos = old->next;
rte_free_quick(old);
tab->rt_count--;
break;
}
if (!new)
{
if (!old)
goto drop_withdraw;
return 1;
}
/* Insert the new rte */
rte *e = rte_do_cow(new);
e->flags |= REF_COW;
e->net = net;
e->sender = c;
e->lastmod = current_time();
e->next = *pos;
*pos = e;
tab->rt_count++;
return 1;
drop_update:
return refeed;
drop_withdraw:
return 0;
}
/*
* Hostcache
*/
static inline u32
hc_hash(ip_addr a, rtable *dep)
{
......
......@@ -1721,6 +1721,9 @@ bgp_channel_start(struct channel *C)
if (c->cf->import_table)
channel_setup_in_table(C);
if (c->cf->export_table)
channel_setup_out_table(C);
c->stale_timer = tm_new_init(c->pool, bgp_long_lived_stale_timeout, c, 0, 0);
c->next_hop_addr = c->cf->next_hop_addr;
......@@ -2067,6 +2070,7 @@ bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *impor
(new->ext_next_hop != old->ext_next_hop) ||
(new->add_path != old->add_path) ||
(new->import_table != old->import_table) ||
(new->export_table != old->export_table) ||
(IGP_TABLE(new, ip4) != IGP_TABLE(old, ip4)) ||
(IGP_TABLE(new, ip6) != IGP_TABLE(old, ip6)))
return 0;
......
......@@ -150,6 +150,7 @@ struct bgp_channel_config {
u8 ext_next_hop; /* Allow both IPv4 and IPv6 next hops */
u8 add_path; /* Use ADD-PATH extension [RFC 7911] */
u8 import_table; /* Use c.in_table as Adj-RIB-In */
u8 export_table; /* Use c.out_table as Adj-RIB-Out */
struct rtable_config *igp_table_ip4; /* Table for recursive IPv4 next hop lookups */
struct rtable_config *igp_table_ip6; /* Table for recursive IPv6 next hop lookups */
......
......@@ -255,6 +255,7 @@ bgp_channel_item:
| ADD PATHS TX { BGP_CC->add_path = BGP_ADD_PATH_TX; }
| ADD PATHS bool { BGP_CC->add_path = $3 ? BGP_ADD_PATH_FULL : 0; }
| IMPORT TABLE bool { BGP_CC->import_table = $3; }
| EXPORT TABLE bool { BGP_CC->export_table = $3; }
| IGP TABLE rtable {
if (BGP_CC->desc->no_igp)
cf_error("IGP table not allowed here");
......
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