bird/proto/static/static.c

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/*
* 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.
*/
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/**
* DOC: Static
*
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* The Static protocol is implemented in a straightforward way. It keeps
* two lists of static routes: one containing interface routes and one
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* holding the remaining ones. Interface routes are inserted and removed according
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* to interface events received from the core via the if_notify() hook. Routes
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* pointing to a neighboring router use a sticky node in the neighbor cache
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* to be notified about gaining or losing the neighbor. Special
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* routes like black holes or rejects are inserted all the time.
*
* The only other thing worth mentioning is that when asked for reconfiguration,
* Static not only compares the two configurations, but it also calculates
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* difference between the lists of static routes and it just inserts the
* newly added routes and removes the obsolete ones.
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*/
#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 "static.h"
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;
aa = rta_lookup(&a);
n = net_get(p->table, r->net, r->masklen);
e = rte_get_temp(aa);
e->net = n;
e->pflags = 0;
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rte_update(p->table, n, p, p, e);
r->installed = 1;
}
static int
static_decide(struct static_config *cf, struct static_route *r)
{
struct iface *ifa = r->neigh->iface;
if (!ifa)
return 0;
if (cf->check_link && !(ifa->flags & IF_LINK_UP))
return 0;
return 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)
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rte_update(p->table, n, p, p, NULL);
r->installed = 0;
}
static void
static_add(struct proto *p, struct static_config *cf, struct static_route *r)
{
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DBG("static_add(%I/%d,%d)\n", r->net, r->masklen, r->dest);
switch (r->dest)
{
case RTD_ROUTER:
{
struct neighbor *n = neigh_find(p, &r->via, 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);
break;
}
case RTD_DEVICE:
break;
default:
static_install(p, r, NULL);
}
}
static int
static_start(struct proto *p)
{
struct static_config *c = (void *) p->cf;
struct static_route *r;
DBG("Static: take off!\n");
WALK_LIST(r, c->other_routes)
static_add(p, c, r);
return PS_UP;
}
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static int
static_shutdown(struct proto *p)
{
struct static_config *c = (void *) p->cf;
struct static_route *r;
/* Just reset the flag, the routes will be flushed by the nest */
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WALK_LIST(r, c->iface_routes)
r->installed = 0;
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WALK_LIST(r, c->other_routes)
r->installed = 0;
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return PS_DOWN;
}
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)
if (static_decide((struct static_config *) p->cf, r))
static_install(p, r, n->iface);
else
static_remove(p, r);
}
static void
static_dump_rt(struct static_route *r)
{
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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)
{
return (x->dest == y->dest)
&& (x->dest != RTD_ROUTER || ipa_equal(x->via, y->via))
&& (x->dest != RTD_DEVICE || !strcmp(x->if_name, y->if_name));
}
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 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;
/* 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;
}
struct protocol proto_static = {
name: "Static",
template: "static%d",
init: static_init,
dump: static_dump,
start: static_start,
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shutdown: static_shutdown,
reconfigure: static_reconfigure,
};
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", r->via); 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;
default: bsprintf(via, "???");
}
cli_msg(-1009, "%I/%d %s%s", r->net, r->masklen, via, r->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, "");
}