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mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-09-20 04:15:19 +00:00
bird/nest/rt-show.c
Maria Matejka f0507f05ce Route sources have an explicit owner
This commit prevents use-after-free of routes belonging to protocols
which have been already destroyed, delaying also all the protocols'
shutdown until all of their routes have been finally propagated through
all the pipes down to the appropriate exports.

The use-after-free was somehow hypothetic yet theoretically possible in
rare conditions, when one BGP protocol authors a lot of routes and the
user deletes that protocol by reconfiguring in the same time as next hop
update is requested, causing rte_better() to be called on a
not-yet-pruned network prefix while the owner protocol has been already
freed.

In parallel execution environments, this would happen an inter-thread
use-after-free, causing possible heisenbugs or other nasty problems.
2021-11-22 19:05:44 +01:00

464 lines
11 KiB
C

/*
* BIRD -- Route Display Routines
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
* (c) 2017 Jan Moskyto Matejka <mq@jmq.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/cli.h"
#include "nest/iface.h"
#include "filter/filter.h"
#include "sysdep/unix/krt.h"
static void
rt_show_table(struct cli *c, struct rt_show_data *d)
{
/* No table blocks in 'show route count' */
if (d->stats == 2)
return;
if (d->last_table) cli_printf(c, -1007, "");
cli_printf(c, -1007, "Table %s:", d->tab->table->name);
d->last_table = d->tab;
}
static inline struct krt_proto *
rt_show_get_kernel(struct rt_show_data *d)
{
struct proto_config *krt = d->tab->table->config->krt_attached;
return krt ? (struct krt_proto *) krt->proto : NULL;
}
static void
rt_show_rte(struct cli *c, byte *ia, rte *e, struct rt_show_data *d, int primary)
{
byte from[IPA_MAX_TEXT_LENGTH+8];
byte tm[TM_DATETIME_BUFFER_SIZE], info[256];
rta *a = e->attrs;
int sync_error = d->kernel ? krt_get_sync_error(d->kernel, e) : 0;
void (*get_route_info)(struct rte *, byte *buf);
struct nexthop *nh;
tm_format_time(tm, &config->tf_route, e->lastmod);
if (ipa_nonzero(a->from) && !ipa_equal(a->from, a->nh.gw))
bsprintf(from, " from %I", a->from);
else
from[0] = 0;
/* Need to normalize the extended attributes */
if (d->verbose && !rta_is_cached(a) && a->eattrs)
ea_normalize(a->eattrs);
get_route_info = e->src->owner->class ? e->src->owner->class->get_route_info : NULL;
if (get_route_info)
get_route_info(e, info);
else
bsprintf(info, " (%d)", a->pref);
if (d->last_table != d->tab)
rt_show_table(c, d);
cli_printf(c, -1007, "%-20s %s [%s %s%s]%s%s", ia, rta_dest_name(a->dest),
e->src->owner->name, tm, from, primary ? (sync_error ? " !" : " *") : "", info);
if (a->dest == RTD_UNICAST)
for (nh = &(a->nh); nh; nh = nh->next)
{
char mpls[MPLS_MAX_LABEL_STACK*12 + 5], *lsp = mpls;
char *onlink = (nh->flags & RNF_ONLINK) ? " onlink" : "";
char weight[16] = "";
if (nh->labels)
{
lsp += bsprintf(lsp, " mpls %d", nh->label[0]);
for (int i=1;i<nh->labels; i++)
lsp += bsprintf(lsp, "/%d", nh->label[i]);
}
*lsp = '\0';
if (a->nh.next)
bsprintf(weight, " weight %d", nh->weight + 1);
if (ipa_nonzero(nh->gw))
cli_printf(c, -1007, "\tvia %I on %s%s%s%s",
nh->gw, nh->iface->name, mpls, onlink, weight);
else
cli_printf(c, -1007, "\tdev %s%s%s",
nh->iface->name, mpls, onlink, weight);
}
if (d->verbose)
{
cli_printf(c, -1008, "\tInternal route ID: %uL %uG %uS", e->src->private_id, e->src->global_id, e->stale_cycle);
rta_show(c, a);
}
}
static uint
rte_feed_count(net *n)
{
uint count = 0;
for (struct rte_storage *e = n->routes; e; e = e->next)
if (rte_is_valid(RTES_OR_NULL(e)))
count++;
return count;
}
static void
rte_feed_obtain(net *n, rte **feed, uint count)
{
uint i = 0;
for (struct rte_storage *e = n->routes; e; e = e->next)
if (rte_is_valid(RTES_OR_NULL(e)))
{
ASSERT_DIE(i < count);
feed[i++] = &e->rte;
}
ASSERT_DIE(i == count);
}
static void
rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
{
byte ia[NET_MAX_TEXT_LENGTH+1];
struct channel *ec = d->tab->export_channel;
/* The Clang static analyzer complains that ec may be NULL.
* It should be ensured to be not NULL by rt_show_prepare_tables() */
ASSUME(!d->export_mode || ec);
int first = 1;
int pass = 0;
bsnprintf(ia, sizeof(ia), "%N", n->n.addr);
for (struct rte_storage *er = n->routes; er; er = er->next)
{
if (rte_is_filtered(&er->rte) != d->filtered)
continue;
d->rt_counter++;
d->net_counter += first;
first = 0;
if (pass)
continue;
struct rte e = er->rte;
/* Export channel is down, do not try to export routes to it */
if (ec && !ec->out_req.hook)
goto skip;
if (d->export_mode == RSEM_EXPORTED)
{
if (!bmap_test(&ec->export_map, e.id))
goto skip;
// if (ec->ra_mode != RA_ANY)
// pass = 1;
}
else if ((d->export_mode == RSEM_EXPORT) && (ec->ra_mode == RA_MERGED))
{
/* Special case for merged export */
pass = 1;
uint count = rte_feed_count(n);
if (!count)
goto skip;
rte **feed = alloca(count * sizeof(rte *));
rte_feed_obtain(n, feed, count);
rte *em = rt_export_merged(ec, feed, count, c->show_pool, 1);
if (em)
e = *em;
else
goto skip;
}
else if (d->export_mode)
{
struct proto *ep = ec->proto;
int ic = ep->preexport ? ep->preexport(ec, &e) : 0;
if (ec->ra_mode == RA_OPTIMAL || ec->ra_mode == RA_MERGED)
pass = 1;
if (ic < 0)
goto skip;
if (d->export_mode > RSEM_PREEXPORT)
{
/*
* FIXME - This shows what should be exported according to current
* filters, but not what was really exported. 'configure soft'
* command may change the export filter and do not update routes.
*/
int do_export = (ic > 0) ||
(f_run(ec->out_filter, &e, c->show_pool, FF_SILENT) <= F_ACCEPT);
if (do_export != (d->export_mode == RSEM_EXPORT))
goto skip;
if ((d->export_mode == RSEM_EXPORT) && (ec->ra_mode == RA_ACCEPTED))
pass = 1;
}
}
if (d->show_protocol && (&d->show_protocol->sources != e.src->owner))
goto skip;
if (f_run(d->filter, &e, c->show_pool, 0) > F_ACCEPT)
goto skip;
if (d->stats < 2)
rt_show_rte(c, ia, &e, d, (n->routes == er));
d->show_counter++;
ia[0] = 0;
skip:
lp_flush(c->show_pool);
if (d->primary_only)
break;
}
}
static void
rt_show_cleanup(struct cli *c)
{
struct rt_show_data *d = c->rover;
struct rt_show_data_rtable *tab;
/* Unlink the iterator */
if (d->table_open)
fit_get(&d->tab->table->fib, &d->fit);
/* Unlock referenced tables */
WALK_LIST(tab, d->tables)
rt_unlock_table(tab->table);
}
static void
rt_show_cont(struct cli *c)
{
struct rt_show_data *d = c->rover;
#ifdef DEBUGGING
unsigned max = 4;
#else
unsigned max = 64;
#endif
struct fib *fib = &d->tab->table->fib;
struct fib_iterator *it = &d->fit;
if (d->running_on_config && (d->running_on_config != config))
{
cli_printf(c, 8004, "Stopped due to reconfiguration");
goto done;
}
if (!d->table_open)
{
FIB_ITERATE_INIT(&d->fit, &d->tab->table->fib);
d->table_open = 1;
d->table_counter++;
d->kernel = rt_show_get_kernel(d);
d->show_counter_last = d->show_counter;
d->rt_counter_last = d->rt_counter;
d->net_counter_last = d->net_counter;
if (d->tables_defined_by & RSD_TDB_SET)
rt_show_table(c, d);
}
FIB_ITERATE_START(fib, it, net, n)
{
if (!max--)
{
FIB_ITERATE_PUT(it);
return;
}
rt_show_net(c, n, d);
}
FIB_ITERATE_END;
if (d->stats)
{
if (d->last_table != d->tab)
rt_show_table(c, d);
cli_printf(c, -1007, "%d of %d routes for %d networks in table %s",
d->show_counter - d->show_counter_last, d->rt_counter - d->rt_counter_last,
d->net_counter - d->net_counter_last, d->tab->table->name);
}
d->kernel = NULL;
d->table_open = 0;
d->tab = NODE_NEXT(d->tab);
if (NODE_VALID(d->tab))
return;
if (d->stats && (d->table_counter > 1))
{
if (d->last_table) cli_printf(c, -1007, "");
cli_printf(c, 14, "Total: %d of %d routes for %d networks in %d tables",
d->show_counter, d->rt_counter, d->net_counter, d->table_counter);
}
else
cli_printf(c, 0, "");
done:
rt_show_cleanup(c);
c->cont = c->cleanup = NULL;
}
struct rt_show_data_rtable *
rt_show_add_table(struct rt_show_data *d, rtable *t)
{
struct rt_show_data_rtable *tab = cfg_allocz(sizeof(struct rt_show_data_rtable));
tab->table = t;
add_tail(&(d->tables), &(tab->n));
return tab;
}
static inline void
rt_show_get_default_tables(struct rt_show_data *d)
{
struct channel *c;
struct rt_show_data_rtable *tab;
if (d->export_channel)
{
c = d->export_channel;
tab = rt_show_add_table(d, c->table);
tab->export_channel = c;
return;
}
if (d->export_protocol)
{
WALK_LIST(c, d->export_protocol->channels)
{
if (!c->out_req.hook)
continue;
tab = rt_show_add_table(d, c->table);
tab->export_channel = c;
}
return;
}
if (d->show_protocol)
{
WALK_LIST(c, d->show_protocol->channels)
rt_show_add_table(d, c->table);
return;
}
for (int i=1; i<NET_MAX; i++)
if (config->def_tables[i] && config->def_tables[i]->table)
rt_show_add_table(d, config->def_tables[i]->table);
}
static inline void
rt_show_prepare_tables(struct rt_show_data *d)
{
struct rt_show_data_rtable *tab, *tabx;
/* Add implicit tables if no table is specified */
if (EMPTY_LIST(d->tables))
rt_show_get_default_tables(d);
WALK_LIST_DELSAFE(tab, tabx, d->tables)
{
/* Ensure there is defined export_channel for each table */
if (d->export_mode)
{
if (!tab->export_channel && d->export_channel &&
(tab->table == d->export_channel->table))
tab->export_channel = d->export_channel;
if (!tab->export_channel && d->export_protocol)
tab->export_channel = proto_find_channel_by_table(d->export_protocol, tab->table);
if (!tab->export_channel)
{
if (d->tables_defined_by & RSD_TDB_NMN)
cf_error("No export channel for table %s", tab->table->name);
rem_node(&(tab->n));
continue;
}
}
/* Ensure specified network is compatible with each table */
if (d->addr && (tab->table->addr_type != d->addr->type))
{
if (d->tables_defined_by & RSD_TDB_NMN)
cf_error("Incompatible type of prefix/ip for table %s", tab->table->name);
rem_node(&(tab->n));
continue;
}
}
/* Ensure there is at least one table */
if (EMPTY_LIST(d->tables))
cf_error("No valid tables");
}
void
rt_show(struct rt_show_data *d)
{
struct rt_show_data_rtable *tab;
net *n;
/* Filtered routes are neither exported nor have sensible ordering */
if (d->filtered && (d->export_mode || d->primary_only))
cf_error("Incompatible show route options");
rt_show_prepare_tables(d);
if (!d->addr)
{
WALK_LIST(tab, d->tables)
rt_lock_table(tab->table);
/* There is at least one table */
d->tab = HEAD(d->tables);
this_cli->cont = rt_show_cont;
this_cli->cleanup = rt_show_cleanup;
this_cli->rover = d;
}
else
{
WALK_LIST(tab, d->tables)
{
d->tab = tab;
d->kernel = rt_show_get_kernel(d);
if (d->show_for)
n = net_route(tab->table, d->addr);
else
n = net_find(tab->table, d->addr);
if (n)
rt_show_net(this_cli, n, d);
}
if (d->rt_counter)
cli_msg(0, "");
else
cli_msg(8001, "Network not found");
}
}