bird/proto/static/static.c
2012-01-09 03:21:45 +01:00

571 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)
return;
DBG("Installing static route %I/%d, rtd=%d\n", r->net, r->masklen, r->dest);
bzero(&a, sizeof(a));
a.proto = p;
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->table, n, p, p, 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\n", r->net, r->masklen);
n = net_find(p->table, r->net, r->masklen);
if (n)
rte_update(p->table, n, p, p, 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);
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)
{
c->c.preference = DEF_PREF_STATIC;
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))
{
t->installed = r->installed && static_same_dest(r, t);
return;
}
WALK_LIST(t, n->other_routes)
if (static_same_net(r, t))
{
t->installed = r->installed && static_same_dest(r, t);
return;
}
static_remove(p, r);
}
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))
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",
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, "");
}