bird/proto/static/static.c
Ondrej Zajicek d40c26594c Fixes issues with static protocol reconfiguration.
The old static route was not removed when the nexthop changed and the
new one was not viable (no neighbor).

Thanks to Pierluigi Rolando for the original patch.
2014-02-26 16:01:20 +01:00

579 lines
14 KiB
C

/*
* BIRD -- Static Route Generator
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Static
*
* The Static protocol is implemented in a straightforward way. It keeps
* two lists of static routes: one containing interface routes and one
* holding the remaining ones. Interface routes are inserted and removed according
* to interface events received from the core via the if_notify() hook. Routes
* pointing to a neighboring router use a sticky node in the neighbor cache
* to be notified about gaining or losing the neighbor. Special
* routes like black holes or rejects are inserted all the time.
*
* Multipath routes are tricky. Because these routes depends on
* several neighbors we need to integrate that to the neighbor
* notification handling, we use dummy static_route nodes, one for
* each nexthop. Therefore, a multipath route consists of a master
* static_route node (of dest RTD_MULTIPATH), which specifies prefix
* and is used in most circumstances, and a list of dummy static_route
* nodes (of dest RTD_NONE), which stores info about nexthops and are
* connected to neighbor entries and neighbor notifications. Dummy
* nodes are chained using mp_next, they aren't in other_routes list,
* and abuse some fields (masklen, if_name) for other purposes.
*
* The only other thing worth mentioning is that when asked for reconfiguration,
* Static not only compares the two configurations, but it also calculates
* difference between the lists of static routes and it just inserts the
* newly added routes and removes the obsolete ones.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "nest/cli.h"
#include "conf/conf.h"
#include "lib/string.h"
#include "lib/alloca.h"
#include "static.h"
static inline rtable *
p_igp_table(struct proto *p)
{
struct static_config *cf = (void *) p->cf;
return cf->igp_table ? cf->igp_table->table : p->table;
}
static void
static_install(struct proto *p, struct static_route *r, struct iface *ifa)
{
net *n;
rta a, *aa;
rte *e;
if (r->installed > 0)
return;
DBG("Installing static route %I/%d, rtd=%d\n", r->net, r->masklen, r->dest);
bzero(&a, sizeof(a));
a.src = p->main_source;
a.source = (r->dest == RTD_DEVICE) ? RTS_STATIC_DEVICE : RTS_STATIC;
a.scope = SCOPE_UNIVERSE;
a.cast = RTC_UNICAST;
a.dest = r->dest;
a.gw = r->via;
a.iface = ifa;
if (r->dest == RTD_MULTIPATH)
{
struct static_route *r2;
struct mpnh *nhs = NULL;
struct mpnh **nhp = &nhs;
for (r2 = r->mp_next; r2; r2 = r2->mp_next)
if (r2->installed)
{
struct mpnh *nh = alloca(sizeof(struct mpnh));
nh->gw = r2->via;
nh->iface = r2->neigh->iface;
nh->weight = r2->masklen; /* really */
nh->next = NULL;
*nhp = nh;
nhp = &(nh->next);
}
/* There is at least one nexthop */
if (!nhs->next)
{
/* Fallback to unipath route for exactly one nexthop */
a.dest = RTD_ROUTER;
a.gw = nhs->gw;
a.iface = nhs->iface;
}
else
a.nexthops = nhs;
}
if (r->dest == RTDX_RECURSIVE)
rta_set_recursive_next_hop(p->table, &a, p_igp_table(p), &r->via, &r->via);
aa = rta_lookup(&a);
n = net_get(p->table, r->net, r->masklen);
e = rte_get_temp(aa);
e->net = n;
e->pflags = 0;
rte_update(p, n, e);
r->installed = 1;
}
static void
static_remove(struct proto *p, struct static_route *r)
{
net *n;
if (!r->installed)
return;
DBG("Removing static route %I/%d via %I\n", r->net, r->masklen, r->via);
n = net_find(p->table, r->net, r->masklen);
rte_update(p, n, NULL);
r->installed = 0;
}
static int
static_decide(struct static_config *cf, struct static_route *r)
{
/* r->dest != RTD_MULTIPATH, but may be RTD_NONE (part of multipath route)
the route also have to be valid (r->neigh != NULL) */
if (r->neigh->scope < 0)
return 0;
if (cf->check_link && !(r->neigh->iface->flags & IF_LINK_UP))
return 0;
return 1;
}
static void
static_add(struct proto *p, struct static_config *cf, struct static_route *r)
{
DBG("static_add(%I/%d,%d)\n", r->net, r->masklen, r->dest);
switch (r->dest)
{
case RTD_ROUTER:
{
struct neighbor *n = neigh_find2(p, &r->via, r->via_if, NEF_STICKY);
if (n)
{
r->chain = n->data;
n->data = r;
r->neigh = n;
if (static_decide(cf, r))
static_install(p, r, n->iface);
else
static_remove(p, r);
}
else
{
log(L_ERR "Static route destination %I is invalid. Ignoring.", r->via);
static_remove(p, r);
}
break;
}
case RTD_DEVICE:
break;
case RTD_MULTIPATH:
{
int count = 0;
struct static_route *r2;
for (r2 = r->mp_next; r2; r2 = r2->mp_next)
{
struct neighbor *n = neigh_find2(p, &r2->via, r2->via_if, NEF_STICKY);
if (n)
{
r2->chain = n->data;
n->data = r2;
r2->neigh = n;
r2->installed = static_decide(cf, r2);
count += r2->installed;
}
else
{
log(L_ERR "Static route destination %I is invalid. Ignoring.", r2->via);
r2->installed = 0;
}
}
if (count)
static_install(p, r, NULL);
else
static_remove(p, r);
break;
}
default:
static_install(p, r, NULL);
}
}
static int
static_start(struct proto *p)
{
struct static_config *cf = (void *) p->cf;
struct static_route *r;
DBG("Static: take off!\n");
if (cf->igp_table)
rt_lock_table(cf->igp_table->table);
/* We have to go UP before routes could be installed */
proto_notify_state(p, PS_UP);
WALK_LIST(r, cf->other_routes)
static_add(p, cf, r);
return PS_UP;
}
static int
static_shutdown(struct proto *p)
{
struct static_config *cf = (void *) p->cf;
struct static_route *r;
/* Just reset the flag, the routes will be flushed by the nest */
WALK_LIST(r, cf->iface_routes)
r->installed = 0;
WALK_LIST(r, cf->other_routes)
r->installed = 0;
return PS_DOWN;
}
static void
static_cleanup(struct proto *p)
{
struct static_config *cf = (void *) p->cf;
if (cf->igp_table)
rt_unlock_table(cf->igp_table->table);
}
static void
static_neigh_notify(struct neighbor *n)
{
struct proto *p = n->proto;
struct static_route *r;
DBG("Static: neighbor notify for %I: iface %p\n", n->addr, n->iface);
for(r=n->data; r; r=r->chain)
switch (r->dest)
{
case RTD_ROUTER:
if (static_decide((struct static_config *) p->cf, r))
static_install(p, r, n->iface);
else
static_remove(p, r);
break;
case RTD_NONE: /* a part of multipath route */
{
int decision = static_decide((struct static_config *) p->cf, r);
if (decision == r->installed)
break; /* no change */
r->installed = decision;
struct static_route *r1, *r2;
int count = 0;
r1 = (void *) r->if_name; /* really */
for (r2 = r1->mp_next; r2; r2 = r2->mp_next)
count += r2->installed;
if (count)
{
/* Set of nexthops changed - force reinstall */
r1->installed = 0;
static_install(p, r1, NULL);
}
else
static_remove(p, r1);
break;
}
}
}
static void
static_dump_rt(struct static_route *r)
{
debug("%-1I/%2d: ", r->net, r->masklen);
switch (r->dest)
{
case RTD_ROUTER:
debug("via %I\n", r->via);
break;
case RTD_DEVICE:
debug("dev %s\n", r->if_name);
break;
default:
debug("rtd %d\n", r->dest);
break;
}
}
static void
static_dump(struct proto *p)
{
struct static_config *c = (void *) p->cf;
struct static_route *r;
debug("Independent static routes:\n");
WALK_LIST(r, c->other_routes)
static_dump_rt(r);
debug("Device static routes:\n");
WALK_LIST(r, c->iface_routes)
static_dump_rt(r);
}
static void
static_if_notify(struct proto *p, unsigned flags, struct iface *i)
{
struct static_route *r;
struct static_config *c = (void *) p->cf;
if (flags & IF_CHANGE_UP)
{
WALK_LIST(r, c->iface_routes)
if (!strcmp(r->if_name, i->name))
static_install(p, r, i);
}
else if (flags & IF_CHANGE_DOWN)
{
WALK_LIST(r, c->iface_routes)
if (!strcmp(r->if_name, i->name))
static_remove(p, r);
}
}
void
static_init_config(struct static_config *c)
{
init_list(&c->iface_routes);
init_list(&c->other_routes);
}
static struct proto *
static_init(struct proto_config *c)
{
struct proto *p = proto_new(c, sizeof(struct proto));
p->neigh_notify = static_neigh_notify;
p->if_notify = static_if_notify;
return p;
}
static inline int
static_same_net(struct static_route *x, struct static_route *y)
{
return ipa_equal(x->net, y->net) && (x->masklen == y->masklen);
}
static inline int
static_same_dest(struct static_route *x, struct static_route *y)
{
if (x->dest != y->dest)
return 0;
switch (x->dest)
{
case RTD_ROUTER:
return ipa_equal(x->via, y->via) && (x->via_if == y->via_if);
case RTD_DEVICE:
return !strcmp(x->if_name, y->if_name);
case RTD_MULTIPATH:
for (x = x->mp_next, y = y->mp_next;
x && y;
x = x->mp_next, y = y->mp_next)
if (!ipa_equal(x->via, y->via) || (x->via_if != y->via_if))
return 0;
return !x && !y;
case RTDX_RECURSIVE:
return ipa_equal(x->via, y->via);
default:
return 1;
}
}
static void
static_match(struct proto *p, struct static_route *r, struct static_config *n)
{
struct static_route *t;
/*
* For given old route *r we find whether a route to the same
* network is also in the new route list. In that case, we keep the
* route and possibly update the route later if destination changed.
* Otherwise, we remove the route.
*/
if (r->neigh)
r->neigh->data = NULL;
WALK_LIST(t, n->iface_routes)
if (static_same_net(r, t))
goto found;
WALK_LIST(t, n->other_routes)
if (static_same_net(r, t))
goto found;
static_remove(p, r);
return;
found:
/* If destination is different, force reinstall */
if ((r->installed > 0) && !static_same_dest(r, t))
t->installed = -1;
else
t->installed = r->installed;
}
static inline rtable *
cf_igp_table(struct static_config *cf)
{
return cf->igp_table ? cf->igp_table->table : NULL;
}
static int
static_reconfigure(struct proto *p, struct proto_config *new)
{
struct static_config *o = (void *) p->cf;
struct static_config *n = (void *) new;
struct static_route *r;
if (cf_igp_table(o) != cf_igp_table(n))
return 0;
/* Delete all obsolete routes and reset neighbor entries */
WALK_LIST(r, o->iface_routes)
static_match(p, r, n);
WALK_LIST(r, o->other_routes)
static_match(p, r, n);
/* Now add all new routes, those not changed will be ignored by static_install() */
WALK_LIST(r, n->iface_routes)
{
struct iface *ifa;
if ((ifa = if_find_by_name(r->if_name)) && (ifa->flags & IF_UP))
static_install(p, r, ifa);
}
WALK_LIST(r, n->other_routes)
static_add(p, n, r);
return 1;
}
static void
static_copy_routes(list *dlst, list *slst)
{
struct static_route *dr, *sr;
init_list(dlst);
WALK_LIST(sr, *slst)
{
/* copy one route */
dr = cfg_alloc(sizeof(struct static_route));
memcpy(dr, sr, sizeof(struct static_route));
/* This fn is supposed to be called on fresh src routes, which have 'live'
fields (like .chain, .neigh or .installed) zero, so no need to zero them */
/* We need to copy multipath chain, because there are backptrs in 'if_name' */
if (dr->dest == RTD_MULTIPATH)
{
struct static_route *md, *ms, **mp_last;
mp_last = &(dr->mp_next);
for (ms = sr->mp_next; ms; ms = ms->mp_next)
{
md = cfg_alloc(sizeof(struct static_route));
memcpy(md, ms, sizeof(struct static_route));
md->if_name = (void *) dr; /* really */
*mp_last = md;
mp_last = &(md->mp_next);
}
*mp_last = NULL;
}
add_tail(dlst, (node *) dr);
}
}
static void
static_copy_config(struct proto_config *dest, struct proto_config *src)
{
struct static_config *d = (struct static_config *) dest;
struct static_config *s = (struct static_config *) src;
/* Shallow copy of everything */
proto_copy_rest(dest, src, sizeof(struct static_config));
/* Copy route lists */
static_copy_routes(&d->iface_routes, &s->iface_routes);
static_copy_routes(&d->other_routes, &s->other_routes);
}
struct protocol proto_static = {
name: "Static",
template: "static%d",
preference: DEF_PREF_STATIC,
init: static_init,
dump: static_dump,
start: static_start,
shutdown: static_shutdown,
cleanup: static_cleanup,
reconfigure: static_reconfigure,
copy_config: static_copy_config
};
static void
static_show_rt(struct static_route *r)
{
byte via[STD_ADDRESS_P_LENGTH + 16];
switch (r->dest)
{
case RTD_ROUTER: bsprintf(via, "via %I%J", r->via, r->via_if); break;
case RTD_DEVICE: bsprintf(via, "dev %s", r->if_name); break;
case RTD_BLACKHOLE: bsprintf(via, "blackhole"); break;
case RTD_UNREACHABLE: bsprintf(via, "unreachable"); break;
case RTD_PROHIBIT: bsprintf(via, "prohibited"); break;
case RTD_MULTIPATH: bsprintf(via, "multipath"); break;
case RTDX_RECURSIVE: bsprintf(via, "recursive %I", r->via); break;
default: bsprintf(via, "???");
}
cli_msg(-1009, "%I/%d %s%s", r->net, r->masklen, via, r->installed ? "" : " (dormant)");
struct static_route *r2;
if (r->dest == RTD_MULTIPATH)
for (r2 = r->mp_next; r2; r2 = r2->mp_next)
cli_msg(-1009, "\tvia %I%J weight %d%s", r2->via, r2->via_if, r2->masklen + 1, /* really */
r2->installed ? "" : " (dormant)");
}
void
static_show(struct proto *P)
{
struct static_config *c = (void *) P->cf;
struct static_route *r;
WALK_LIST(r, c->other_routes)
static_show_rt(r);
WALK_LIST(r, c->iface_routes)
static_show_rt(r);
cli_msg(0, "");
}