bird/sysdep/unix/krt.c

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/*
* BIRD -- UNIX Kernel Synchronization
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Kernel synchronization
*
* This system dependent module implements the Kernel and Device protocol,
* that is synchronization of interface lists and routing tables with the
* OS kernel.
*
* The whole kernel synchronization is a bit messy and touches some internals
* of the routing table engine, because routing table maintenance is a typical
* example of the proverbial compatibility between different Unices and we want
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* to keep the overhead of our KRT business as low as possible and avoid maintaining
* a local routing table copy.
*
* The kernel syncer can work in three different modes (according to system config header):
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* Either with a single routing table and single KRT protocol [traditional UNIX]
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* or with many routing tables and separate KRT protocols for all of them
* or with many routing tables, but every scan including all tables, so we start
* separate KRT protocols which cooperate with each other [Linux].
* In this case, we keep only a single scan timer.
*
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* We use FIB node flags in the routing table to keep track of route
* synchronization status. We also attach temporary &rte's to the routing table,
* but it cannot do any harm to the rest of BIRD since table synchronization is
* an atomic process.
*
* When starting up, we cheat by looking if there is another
* KRT instance to be initialized later and performing table scan
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* only once for all the instances.
*
* The code uses OS-dependent parts for kernel updates and scans. These parts are
* in more specific sysdep directories (e.g. sysdep/linux) in functions krt_sys_*
* and kif_sys_* (and some others like krt_replace_rte()) and krt-sys.h header file.
* This is also used for platform specific protocol options and route attributes.
*
* There was also an old code that used traditional UNIX ioctls for these tasks.
* It was unmaintained and later removed. For reference, see sysdep/krt-* files
* in commit 396dfa9042305f62da1f56589c4b98fac57fc2f6
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*/
/*
* If you are brave enough, continue now. You cannot say you haven't been warned.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "filter/filter.h"
#include "conf/conf.h"
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#include "lib/string.h"
#include "lib/timer.h"
#include "unix.h"
#include "krt.h"
/*
* Global resources
*/
pool *krt_pool;
static linpool *krt_filter_lp;
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static list krt_proto_list;
void
krt_io_init(void)
{
krt_pool = rp_new(&root_pool, "Kernel Syncer");
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krt_filter_lp = lp_new_default(krt_pool);
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init_list(&krt_proto_list);
krt_sys_io_init();
}
/*
* Interfaces
*/
struct kif_proto *kif_proto;
static struct kif_config *kif_cf;
static timer *kif_scan_timer;
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static btime kif_last_shot;
static struct kif_iface_config kif_default_iface = {};
struct kif_iface_config *
kif_get_iface_config(struct iface *iface)
{
struct kif_config *cf = (void *) (kif_proto->p.cf);
struct kif_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
return ic ?: &kif_default_iface;
}
static void
kif_scan(timer *t)
{
struct kif_proto *p = t->data;
KRT_TRACE(p, D_EVENTS, "Scanning interfaces");
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kif_last_shot = current_time();
kif_do_scan(p);
}
static void
kif_force_scan(void)
{
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if (kif_proto && ((kif_last_shot + 2 S) < current_time()))
{
kif_scan(kif_scan_timer);
tm_start(kif_scan_timer, ((struct kif_config *) kif_proto->p.cf)->scan_time);
}
}
void
kif_request_scan(void)
{
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if (kif_proto && (kif_scan_timer->expires > (current_time() + 1 S)))
tm_start(kif_scan_timer, 1 S);
}
static struct proto *
kif_init(struct proto_config *c)
{
struct kif_proto *p = proto_new(c);
kif_sys_init(p);
return &p->p;
}
static int
kif_start(struct proto *P)
{
struct kif_proto *p = (struct kif_proto *) P;
kif_proto = p;
kif_sys_start(p);
/* Start periodic interface scanning */
kif_scan_timer = tm_new_init(P->pool, kif_scan, p, KIF_CF->scan_time, 0);
kif_scan(kif_scan_timer);
tm_start(kif_scan_timer, KIF_CF->scan_time);
return PS_UP;
}
static int
kif_shutdown(struct proto *P)
{
struct kif_proto *p = (struct kif_proto *) P;
tm_stop(kif_scan_timer);
kif_sys_shutdown(p);
kif_proto = NULL;
return PS_DOWN;
}
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static int
kif_reconfigure(struct proto *p, struct proto_config *new)
{
struct kif_config *o = (struct kif_config *) p->cf;
struct kif_config *n = (struct kif_config *) new;
if (!kif_sys_reconfigure((struct kif_proto *) p, n, o))
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return 0;
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if (o->scan_time != n->scan_time)
{
tm_stop(kif_scan_timer);
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kif_scan_timer->recurrent = n->scan_time;
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kif_scan(kif_scan_timer);
tm_start(kif_scan_timer, n->scan_time);
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}
if (!EMPTY_LIST(o->iface_list) || !EMPTY_LIST(n->iface_list))
{
/* This is hack, we have to update a configuration
* to the new value just now, because it is used
* for recalculation of preferred addresses.
*/
p->cf = new;
if_recalc_all_preferred_addresses();
}
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return 1;
}
static void
kif_preconfig(struct protocol *P UNUSED, struct config *c)
{
kif_cf = NULL;
kif_sys_preconfig(c);
}
struct proto_config *
kif_init_config(int class)
{
if (kif_cf)
cf_error("Kernel device protocol already defined");
kif_cf = (struct kif_config *) proto_config_new(&proto_unix_iface, class);
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kif_cf->scan_time = 60 S;
init_list(&kif_cf->iface_list);
kif_sys_init_config(kif_cf);
return (struct proto_config *) kif_cf;
}
static void
kif_copy_config(struct proto_config *dest, struct proto_config *src)
{
struct kif_config *d = (struct kif_config *) dest;
struct kif_config *s = (struct kif_config *) src;
/* Copy interface config list */
cfg_copy_list(&d->iface_list, &s->iface_list, sizeof(struct kif_iface_config));
/* Fix sysdep parts */
kif_sys_copy_config(d, s);
}
struct protocol proto_unix_iface = {
.name = "Device",
.template = "device%d",
.class = PROTOCOL_DEVICE,
.proto_size = sizeof(struct kif_proto),
.config_size = sizeof(struct kif_config),
.preconfig = kif_preconfig,
.init = kif_init,
.start = kif_start,
.shutdown = kif_shutdown,
.reconfigure = kif_reconfigure,
.copy_config = kif_copy_config
};
/*
* Tracing of routes
*/
static inline void
krt_trace_in(struct krt_proto *p, rte *e, char *msg)
{
if (p->p.debug & D_PACKETS)
log(L_TRACE "%s: %N: %s", p->p.name, e->net->n.addr, msg);
}
static inline void
krt_trace_in_rl(struct tbf *f, struct krt_proto *p, rte *e, char *msg)
{
if (p->p.debug & D_PACKETS)
log_rl(f, L_TRACE "%s: %N: %s", p->p.name, e->net->n.addr, msg);
}
/*
* Inherited Routes
*/
#ifdef KRT_ALLOW_LEARN
static struct tbf rl_alien = TBF_DEFAULT_LOG_LIMITS;
/*
* krt_same_key() specifies what (aside from the net) is the key in
* kernel routing tables. It should be OS-dependent, this is for
* Linux. It is important for asynchronous alien updates, because a
* positive update is implicitly a negative one for any old route with
* the same key.
*/
static inline int
krt_same_key(rte *a, rte *b)
{
return a->u.krt.metric == b->u.krt.metric;
}
static inline int
krt_uptodate(rte *a, rte *b)
{
if (a->attrs != b->attrs)
return 0;
if (a->u.krt.proto != b->u.krt.proto)
return 0;
return 1;
}
static void
krt_learn_announce_update(struct krt_proto *p, rte *e)
{
net *n = e->net;
rta *aa = rta_clone(e->attrs);
rte *ee = rte_get_temp(aa);
ee->pflags = EA_ID_FLAG(EA_KRT_SOURCE) | EA_ID_FLAG(EA_KRT_METRIC);
ee->u.krt = e->u.krt;
rte_update(&p->p, n->n.addr, ee);
}
static void
krt_learn_announce_delete(struct krt_proto *p, net *n)
{
rte_update(&p->p, n->n.addr, NULL);
}
/* Called when alien route is discovered during scan */
static void
krt_learn_scan(struct krt_proto *p, rte *e)
{
net *n0 = e->net;
net *n = net_get(&p->krt_table, n0->n.addr);
rte *m, **mm;
e->attrs = rta_lookup(e->attrs);
for(mm=&n->routes; m = *mm; mm=&m->next)
if (krt_same_key(m, e))
break;
if (m)
{
if (krt_uptodate(m, e))
{
krt_trace_in_rl(&rl_alien, p, e, "[alien] seen");
rte_free(e);
m->u.krt.seen = 1;
}
else
{
krt_trace_in(p, e, "[alien] updated");
*mm = m->next;
rte_free(m);
m = NULL;
}
}
else
krt_trace_in(p, e, "[alien] created");
if (!m)
{
e->next = n->routes;
n->routes = e;
e->u.krt.seen = 1;
}
}
static void
krt_learn_prune(struct krt_proto *p)
{
struct fib *fib = &p->krt_table.fib;
struct fib_iterator fit;
KRT_TRACE(p, D_EVENTS, "Pruning inherited routes");
FIB_ITERATE_INIT(&fit, fib);
again:
FIB_ITERATE_START(fib, &fit, net, n)
{
rte *e, **ee, *best, **pbest, *old_best;
/*
* Note that old_best may be NULL even if there was an old best route in
* the previous step, because it might be replaced in krt_learn_scan().
* But in that case there is a new valid best route.
*/
old_best = NULL;
best = NULL;
pbest = NULL;
ee = &n->routes;
while (e = *ee)
{
if (e->u.krt.best)
old_best = e;
if (!e->u.krt.seen)
{
*ee = e->next;
rte_free(e);
continue;
}
if (!best || best->u.krt.metric > e->u.krt.metric)
{
best = e;
pbest = ee;
}
e->u.krt.seen = 0;
e->u.krt.best = 0;
ee = &e->next;
}
if (!n->routes)
{
DBG("%I/%d: deleting\n", n->n.prefix, n->n.pxlen);
if (old_best)
krt_learn_announce_delete(p, n);
FIB_ITERATE_PUT(&fit);
fib_delete(fib, n);
goto again;
}
best->u.krt.best = 1;
*pbest = best->next;
best->next = n->routes;
n->routes = best;
if ((best != old_best) || p->reload)
{
DBG("%I/%d: announcing (metric=%d)\n", n->n.prefix, n->n.pxlen, best->u.krt.metric);
krt_learn_announce_update(p, best);
}
else
DBG("%I/%d: uptodate (metric=%d)\n", n->n.prefix, n->n.pxlen, best->u.krt.metric);
}
FIB_ITERATE_END;
p->reload = 0;
}
static void
krt_learn_async(struct krt_proto *p, rte *e, int new)
{
net *n0 = e->net;
net *n = net_get(&p->krt_table, n0->n.addr);
rte *g, **gg, *best, **bestp, *old_best;
e->attrs = rta_lookup(e->attrs);
old_best = n->routes;
for(gg=&n->routes; g = *gg; gg = &g->next)
if (krt_same_key(g, e))
break;
if (new)
{
if (g)
{
if (krt_uptodate(g, e))
{
krt_trace_in(p, e, "[alien async] same");
rte_free(e);
return;
}
krt_trace_in(p, e, "[alien async] updated");
*gg = g->next;
rte_free(g);
}
else
krt_trace_in(p, e, "[alien async] created");
e->next = n->routes;
n->routes = e;
}
else if (!g)
{
krt_trace_in(p, e, "[alien async] delete failed");
rte_free(e);
return;
}
else
{
krt_trace_in(p, e, "[alien async] removed");
*gg = g->next;
rte_free(e);
rte_free(g);
}
best = n->routes;
bestp = &n->routes;
for(gg=&n->routes; g=*gg; gg=&g->next)
{
if (best->u.krt.metric > g->u.krt.metric)
{
best = g;
bestp = gg;
}
g->u.krt.best = 0;
}
if (best)
{
best->u.krt.best = 1;
*bestp = best->next;
best->next = n->routes;
n->routes = best;
}
if (best != old_best)
{
DBG("krt_learn_async: distributing change\n");
if (best)
krt_learn_announce_update(p, best);
else
krt_learn_announce_delete(p, n);
}
}
static void
krt_learn_init(struct krt_proto *p)
{
if (KRT_CF->learn)
{
struct rtable_config *cf = mb_allocz(p->p.pool, sizeof(struct rtable_config));
cf->name = "Inherited";
cf->addr_type = p->p.net_type;
rt_setup(p->p.pool, &p->krt_table, cf);
}
}
static void
krt_dump(struct proto *P)
{
struct krt_proto *p = (struct krt_proto *) P;
if (!KRT_CF->learn)
return;
debug("KRT: Table of inheritable routes\n");
rt_dump(&p->krt_table);
}
static void
krt_dump_attrs(rte *e)
{
debug(" [m=%d,p=%d]", e->u.krt.metric, e->u.krt.proto);
}
#endif
/*
* Routes
*/
static void
krt_flush_routes(struct krt_proto *p)
{
struct rtable *t = p->p.main_channel->table;
KRT_TRACE(p, D_EVENTS, "Flushing kernel routes");
FIB_WALK(&t->fib, net, n)
{
rte *e = n->routes;
if (rte_is_valid(e) && (n->n.flags & KRF_INSTALLED))
{
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/* FIXME: this does not work if gw is changed in export filter */
krt_replace_rte(p, e->net, NULL, e);
2012-05-03 20:04:56 +08:00
n->n.flags &= ~KRF_INSTALLED;
}
}
FIB_WALK_END;
}
static struct rte *
krt_export_net(struct krt_proto *p, net *net, rte **rt_free)
{
struct channel *c = p->p.main_channel;
const struct filter *filter = c->out_filter;
rte *rt;
if (c->ra_mode == RA_MERGED)
return rt_export_merged(c, net, rt_free, krt_filter_lp, 1);
rt = net->routes;
*rt_free = NULL;
if (!rte_is_valid(rt))
return NULL;
if (filter == FILTER_REJECT)
return NULL;
rte_make_tmp_attrs(&rt, krt_filter_lp, NULL);
Terminology cleanup: The import_control hook is now called preexport. Once upon a time, far far away, there were the old Bird developers discussing what direction of route flow shall be called import and export. They decided to say "import to protocol" and "export to table" when speaking about a protocol. When speaking about a table, they spoke about "importing to table" and "exporting to protocol". The latter terminology was adopted in configuration, then also the bird CLI in commit ea2ae6dd0 started to use it (in year 2009). Now it's 2018 and the terminology is the latter. Import is from protocol to table, export is from table to protocol. Anyway, there was still an import_control hook which executed right before route export. One thing is funny. There are two commits in April 1999 with just two minutes between them. The older announces the final settlement on config terminology, the newer uses the other definition. Let's see their commit messages as the git-log tool shows them (the newer first): commit 9e0e485e50ea74c4f1c5cb65bdfe6ce819c2cee2 Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:17:59 1999 +0000 Added some new protocol hooks (look at the comments for better explanation): make_tmp_attrs Convert inline attributes to ea_list store_tmp_attrs Convert ea_list to inline attributes import_control Pre-import decisions commit 5056c559c4eb253a4eee10cf35b694faec5265eb Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:15:31 1999 +0000 Changed syntax of attaching filters to protocols to hopefully the final version: EXPORT <filter-spec> for outbound routes (i.e., those announced by BIRD to the rest of the world). IMPORT <filter-spec> for inbound routes (i.e., those imported by BIRD from the rest of the world). where <filter-spec> is one of: ALL pass all routes NONE drop all routes FILTER <name> use named filter FILTER { <filter> } use explicitly defined filter For all protocols, the default is IMPORT ALL, EXPORT NONE. This includes the kernel protocol, so that you need to add EXPORT ALL to get the previous configuration of kernel syncer (as usually, see doc/bird.conf.example for a bird.conf example :)). Let's say RIP to this almost 19-years-old inconsistency. For now, if you import a route, it is always from protocol to table. If you export a route, it is always from table to protocol. And they lived happily ever after.
2018-02-14 20:42:53 +08:00
/* We could run krt_preexport() here, but it is already handled by KRF_INSTALLED */
if (filter == FILTER_ACCEPT)
goto accept;
if (f_run(filter, &rt, krt_filter_lp, FF_SILENT) > F_ACCEPT)
goto reject;
accept:
if (rt != net->routes)
*rt_free = rt;
return rt;
reject:
if (rt != net->routes)
rte_free(rt);
return NULL;
}
static int
krt_same_dest(rte *k, rte *e)
{
rta *ka = k->attrs, *ea = e->attrs;
if (ka->dest != ea->dest)
return 0;
if (ka->dest == RTD_UNICAST)
return nexthop_same(&(ka->nh), &(ea->nh));
return 1;
}
/*
* This gets called back when the low-level scanning code discovers a route.
* We expect that the route is a temporary rte and its attributes are uncached.
*/
void
krt_got_route(struct krt_proto *p, rte *e)
{
net *net = e->net;
int verdict;
#ifdef KRT_ALLOW_LEARN
switch (e->u.krt.src)
{
case KRT_SRC_KERNEL:
verdict = KRF_IGNORE;
goto sentenced;
case KRT_SRC_REDIRECT:
verdict = KRF_DELETE;
goto sentenced;
case KRT_SRC_ALIEN:
if (KRT_CF->learn)
krt_learn_scan(p, e);
else
{
krt_trace_in_rl(&rl_alien, p, e, "[alien] ignored");
rte_free(e);
}
return;
}
#endif
/* The rest is for KRT_SRC_BIRD (or KRT_SRC_UNKNOWN) */
if (net->n.flags & KRF_VERDICT_MASK)
{
/* Route to this destination was already seen. Strange, but it happens... */
krt_trace_in(p, e, "already seen");
rte_free(e);
return;
}
if (!p->ready)
{
/* We wait for the initial feed to have correct KRF_INSTALLED flag */
verdict = KRF_IGNORE;
goto sentenced;
}
if (net->n.flags & KRF_INSTALLED)
{
rte *new, *rt_free;
new = krt_export_net(p, net, &rt_free);
/* TODO: There also may be changes in route eattrs, we ignore that for now. */
if (!new)
verdict = KRF_DELETE;
else if ((net->n.flags & KRF_SYNC_ERROR) || !krt_same_dest(e, new))
verdict = KRF_UPDATE;
else
verdict = KRF_SEEN;
if (rt_free)
rte_free(rt_free);
lp_flush(krt_filter_lp);
}
else
verdict = KRF_DELETE;
sentenced:
krt_trace_in(p, e, ((char *[]) { "?", "seen", "will be updated", "will be removed", "ignored" }) [verdict]);
net->n.flags = (net->n.flags & ~KRF_VERDICT_MASK) | verdict;
if (verdict == KRF_UPDATE || verdict == KRF_DELETE)
{
/* Get a cached copy of attributes and temporarily link the route */
rta *a = e->attrs;
a->source = RTS_DUMMY;
e->attrs = rta_lookup(a);
e->next = net->routes;
net->routes = e;
}
else
rte_free(e);
}
static void
krt_prune(struct krt_proto *p)
{
struct rtable *t = p->p.main_channel->table;
KRT_TRACE(p, D_EVENTS, "Pruning table %s", t->name);
FIB_WALK(&t->fib, net, n)
{
int verdict = n->n.flags & KRF_VERDICT_MASK;
rte *new, *old, *rt_free = NULL;
if (verdict == KRF_UPDATE || verdict == KRF_DELETE)
{
/* Get a dummy route from krt_got_route() */
old = n->routes;
n->routes = old->next;
}
else
old = NULL;
if (verdict == KRF_CREATE || verdict == KRF_UPDATE)
{
/* We have to run export filter to get proper 'new' route */
new = krt_export_net(p, n, &rt_free);
if (!new)
verdict = (verdict == KRF_CREATE) ? KRF_IGNORE : KRF_DELETE;
}
else
new = NULL;
switch (verdict)
{
case KRF_CREATE:
if (new && (n->n.flags & KRF_INSTALLED))
{
krt_trace_in(p, new, "reinstalling");
krt_replace_rte(p, n, new, NULL);
}
break;
case KRF_SEEN:
case KRF_IGNORE:
/* Nothing happens */
break;
case KRF_UPDATE:
krt_trace_in(p, new, "updating");
krt_replace_rte(p, n, new, old);
break;
case KRF_DELETE:
krt_trace_in(p, old, "deleting");
krt_replace_rte(p, n, NULL, old);
break;
default:
bug("krt_prune: invalid route status");
}
if (old)
rte_free(old);
if (rt_free)
rte_free(rt_free);
lp_flush(krt_filter_lp);
n->n.flags &= ~KRF_VERDICT_MASK;
}
FIB_WALK_END;
#ifdef KRT_ALLOW_LEARN
if (KRT_CF->learn)
krt_learn_prune(p);
#endif
if (p->ready)
p->initialized = 1;
}
void
krt_got_route_async(struct krt_proto *p, rte *e, int new)
{
net *net = e->net;
switch (e->u.krt.src)
{
case KRT_SRC_BIRD:
/* Should be filtered by the back end */
bug("BIRD originated routes should not get here.");
case KRT_SRC_REDIRECT:
if (new)
{
krt_trace_in(p, e, "[redirect] deleting");
krt_replace_rte(p, net, NULL, e);
}
/* If !new, it is probably echo of our deletion */
break;
#ifdef KRT_ALLOW_LEARN
case KRT_SRC_ALIEN:
if (KRT_CF->learn)
{
krt_learn_async(p, e, new);
return;
}
#endif
}
rte_free(e);
}
/*
* Periodic scanning
*/
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#ifdef CONFIG_ALL_TABLES_AT_ONCE
static timer *krt_scan_timer;
static int krt_scan_count;
static void
krt_scan(timer *t UNUSED)
{
struct krt_proto *p;
kif_force_scan();
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/* We need some node to decide whether to print the debug messages or not */
p = SKIP_BACK(struct krt_proto, krt_node, HEAD(krt_proto_list));
KRT_TRACE(p, D_EVENTS, "Scanning routing table");
krt_do_scan(NULL);
void *q;
WALK_LIST(q, krt_proto_list)
{
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p = SKIP_BACK(struct krt_proto, krt_node, q);
krt_prune(p);
}
}
static void
krt_scan_timer_start(struct krt_proto *p)
{
if (!krt_scan_count)
krt_scan_timer = tm_new_init(krt_pool, krt_scan, NULL, KRT_CF->scan_time, 0);
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krt_scan_count++;
tm_start(krt_scan_timer, 1 S);
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}
static void
krt_scan_timer_stop(struct krt_proto *p UNUSED)
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{
krt_scan_count--;
if (!krt_scan_count)
{
rfree(krt_scan_timer);
krt_scan_timer = NULL;
}
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}
static void
krt_scan_timer_kick(struct krt_proto *p UNUSED)
{
tm_start(krt_scan_timer, 0);
}
#else
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static void
krt_scan(timer *t)
{
struct krt_proto *p = t->data;
kif_force_scan();
KRT_TRACE(p, D_EVENTS, "Scanning routing table");
krt_do_scan(p);
krt_prune(p);
}
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static void
krt_scan_timer_start(struct krt_proto *p)
{
p->scan_timer = tm_new_init(p->p.pool, krt_scan, p, KRT_CF->scan_time, 0);
tm_start(p->scan_timer, 1 S);
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}
static void
krt_scan_timer_stop(struct krt_proto *p)
{
tm_stop(p->scan_timer);
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}
static void
krt_scan_timer_kick(struct krt_proto *p)
{
tm_start(p->scan_timer, 0);
}
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#endif
/*
* Updates
*/
static void
krt_make_tmp_attrs(struct rte *rt, struct linpool *pool)
{
rte_init_tmp_attrs(rt, pool, 2);
rte_make_tmp_attr(rt, EA_KRT_SOURCE, EAF_TYPE_INT, rt->u.krt.proto);
rte_make_tmp_attr(rt, EA_KRT_METRIC, EAF_TYPE_INT, rt->u.krt.metric);
}
static void
krt_store_tmp_attrs(struct rte *rt, struct linpool *pool)
{
rte_init_tmp_attrs(rt, pool, 2);
rt->u.krt.proto = rte_store_tmp_attr(rt, EA_KRT_SOURCE);
rt->u.krt.metric = rte_store_tmp_attr(rt, EA_KRT_METRIC);
}
static int
Terminology cleanup: The import_control hook is now called preexport. Once upon a time, far far away, there were the old Bird developers discussing what direction of route flow shall be called import and export. They decided to say "import to protocol" and "export to table" when speaking about a protocol. When speaking about a table, they spoke about "importing to table" and "exporting to protocol". The latter terminology was adopted in configuration, then also the bird CLI in commit ea2ae6dd0 started to use it (in year 2009). Now it's 2018 and the terminology is the latter. Import is from protocol to table, export is from table to protocol. Anyway, there was still an import_control hook which executed right before route export. One thing is funny. There are two commits in April 1999 with just two minutes between them. The older announces the final settlement on config terminology, the newer uses the other definition. Let's see their commit messages as the git-log tool shows them (the newer first): commit 9e0e485e50ea74c4f1c5cb65bdfe6ce819c2cee2 Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:17:59 1999 +0000 Added some new protocol hooks (look at the comments for better explanation): make_tmp_attrs Convert inline attributes to ea_list store_tmp_attrs Convert ea_list to inline attributes import_control Pre-import decisions commit 5056c559c4eb253a4eee10cf35b694faec5265eb Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:15:31 1999 +0000 Changed syntax of attaching filters to protocols to hopefully the final version: EXPORT <filter-spec> for outbound routes (i.e., those announced by BIRD to the rest of the world). IMPORT <filter-spec> for inbound routes (i.e., those imported by BIRD from the rest of the world). where <filter-spec> is one of: ALL pass all routes NONE drop all routes FILTER <name> use named filter FILTER { <filter> } use explicitly defined filter For all protocols, the default is IMPORT ALL, EXPORT NONE. This includes the kernel protocol, so that you need to add EXPORT ALL to get the previous configuration of kernel syncer (as usually, see doc/bird.conf.example for a bird.conf example :)). Let's say RIP to this almost 19-years-old inconsistency. For now, if you import a route, it is always from protocol to table. If you export a route, it is always from table to protocol. And they lived happily ever after.
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krt_preexport(struct proto *P, rte **new, struct linpool *pool UNUSED)
{
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// struct krt_proto *p = (struct krt_proto *) P;
rte *e = *new;
if (e->attrs->src->proto == P)
{
#ifdef CONFIG_SINGLE_ROUTE
/*
* Implicit withdraw - when the imported kernel route becomes the best one,
* we know that the previous one exported to the kernel was already removed,
* but if we processed the update as usual, we would send withdraw to the
* kernel, which would remove the new imported route instead.
*
* We will remove KRT_INSTALLED flag, which stops such withdraw to be
* processed in krt_rt_notify() and krt_replace_rte().
*/
if (e == e->net->routes)
e->net->n.flags &= ~KRF_INSTALLED;
#endif
return -1;
}
if (!krt_capable(e))
return -1;
return 0;
}
static void
krt_rt_notify(struct proto *P, struct channel *ch UNUSED, net *net,
rte *new, rte *old)
{
struct krt_proto *p = (struct krt_proto *) P;
if (config->shutdown)
return;
if (!(net->n.flags & KRF_INSTALLED))
old = NULL;
if (new)
net->n.flags |= KRF_INSTALLED;
else
net->n.flags &= ~KRF_INSTALLED;
if (p->initialized) /* Before first scan we don't touch the routes */
krt_replace_rte(p, net, new, old);
}
static void
krt_if_notify(struct proto *P, uint flags, struct iface *iface UNUSED)
{
struct krt_proto *p = (struct krt_proto *) P;
/*
* When interface went down, we should remove routes to it. In the ideal world,
* OS kernel would send us route removal notifications in such cases, but we
* cannot rely on it as it is often not true. E.g. Linux kernel removes related
* routes when an interface went down, but it does not notify userspace about
* that. To be sure, we just schedule a scan to ensure synchronization.
*/
if ((flags & IF_CHANGE_DOWN) && KRT_CF->learn)
krt_scan_timer_kick(p);
}
static void
krt_reload_routes(struct channel *C)
{
struct krt_proto *p = (void *) C->proto;
/* Although we keep learned routes in krt_table, we rather schedule a scan */
if (KRT_CF->learn)
{
p->reload = 1;
krt_scan_timer_kick(p);
}
}
static void
krt_feed_end(struct channel *C)
{
struct krt_proto *p = (void *) C->proto;
p->ready = 1;
krt_scan_timer_kick(p);
}
static int
krt_rte_same(rte *a, rte *b)
{
/* src is always KRT_SRC_ALIEN and type is irrelevant */
return (a->u.krt.proto == b->u.krt.proto) && (a->u.krt.metric == b->u.krt.metric);
}
/*
* Protocol glue
*/
struct krt_config *krt_cf;
static void
krt_preconfig(struct protocol *P UNUSED, struct config *c)
{
krt_cf = NULL;
krt_sys_preconfig(c);
}
static void
krt_postconfig(struct proto_config *CF)
{
struct krt_config *cf = (void *) CF;
if (EMPTY_LIST(CF->channels))
cf_error("Channel not specified");
#ifdef CONFIG_ALL_TABLES_AT_ONCE
if (krt_cf->scan_time != cf->scan_time)
cf_error("All kernel syncers must use the same table scan interval");
#endif
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struct channel_config *cc = proto_cf_main_channel(CF);
struct rtable_config *tab = cc->table;
if (tab->krt_attached)
cf_error("Kernel syncer (%s) already attached to table %s", tab->krt_attached->name, tab->name);
tab->krt_attached = CF;
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if (cf->merge_paths)
{
cc->ra_mode = RA_MERGED;
cc->merge_limit = cf->merge_paths;
}
krt_sys_postconfig(cf);
}
static struct proto *
krt_init(struct proto_config *CF)
{
struct krt_proto *p = proto_new(CF);
// struct krt_config *cf = (void *) CF;
p->p.main_channel = proto_add_channel(&p->p, proto_cf_main_channel(CF));
Terminology cleanup: The import_control hook is now called preexport. Once upon a time, far far away, there were the old Bird developers discussing what direction of route flow shall be called import and export. They decided to say "import to protocol" and "export to table" when speaking about a protocol. When speaking about a table, they spoke about "importing to table" and "exporting to protocol". The latter terminology was adopted in configuration, then also the bird CLI in commit ea2ae6dd0 started to use it (in year 2009). Now it's 2018 and the terminology is the latter. Import is from protocol to table, export is from table to protocol. Anyway, there was still an import_control hook which executed right before route export. One thing is funny. There are two commits in April 1999 with just two minutes between them. The older announces the final settlement on config terminology, the newer uses the other definition. Let's see their commit messages as the git-log tool shows them (the newer first): commit 9e0e485e50ea74c4f1c5cb65bdfe6ce819c2cee2 Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:17:59 1999 +0000 Added some new protocol hooks (look at the comments for better explanation): make_tmp_attrs Convert inline attributes to ea_list store_tmp_attrs Convert ea_list to inline attributes import_control Pre-import decisions commit 5056c559c4eb253a4eee10cf35b694faec5265eb Author: Martin Mares <mj@ucw.cz> Date: Mon Apr 5 20:15:31 1999 +0000 Changed syntax of attaching filters to protocols to hopefully the final version: EXPORT <filter-spec> for outbound routes (i.e., those announced by BIRD to the rest of the world). IMPORT <filter-spec> for inbound routes (i.e., those imported by BIRD from the rest of the world). where <filter-spec> is one of: ALL pass all routes NONE drop all routes FILTER <name> use named filter FILTER { <filter> } use explicitly defined filter For all protocols, the default is IMPORT ALL, EXPORT NONE. This includes the kernel protocol, so that you need to add EXPORT ALL to get the previous configuration of kernel syncer (as usually, see doc/bird.conf.example for a bird.conf example :)). Let's say RIP to this almost 19-years-old inconsistency. For now, if you import a route, it is always from protocol to table. If you export a route, it is always from table to protocol. And they lived happily ever after.
2018-02-14 20:42:53 +08:00
p->p.preexport = krt_preexport;
p->p.rt_notify = krt_rt_notify;
p->p.if_notify = krt_if_notify;
p->p.reload_routes = krt_reload_routes;
p->p.feed_end = krt_feed_end;
p->p.make_tmp_attrs = krt_make_tmp_attrs;
p->p.store_tmp_attrs = krt_store_tmp_attrs;
p->p.rte_same = krt_rte_same;
krt_sys_init(p);
return &p->p;
}
static int
krt_start(struct proto *P)
{
struct krt_proto *p = (struct krt_proto *) P;
switch (p->p.net_type)
{
case NET_IP4: p->af = AF_INET; break;
case NET_IP6: p->af = AF_INET6; break;
case NET_IP6_SADR: p->af = AF_INET6; break;
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#ifdef AF_MPLS
case NET_MPLS: p->af = AF_MPLS; break;
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#endif
default: log(L_ERR "KRT: Tried to start with strange net type: %d", p->p.net_type); return PS_START; break;
}
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add_tail(&krt_proto_list, &p->krt_node);
#ifdef KRT_ALLOW_LEARN
krt_learn_init(p);
#endif
if (!krt_sys_start(p))
{
rem_node(&p->krt_node);
return PS_START;
}
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krt_scan_timer_start(p);
if (p->p.gr_recovery && KRT_CF->graceful_restart)
p->p.main_channel->gr_wait = 1;
return PS_UP;
}
static int
krt_shutdown(struct proto *P)
{
struct krt_proto *p = (struct krt_proto *) P;
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krt_scan_timer_stop(p);
/* FIXME we should flush routes even when persist during reconfiguration */
if (p->initialized && !KRT_CF->persist)
krt_flush_routes(p);
p->ready = 0;
p->initialized = 0;
if (p->p.proto_state == PS_START)
return PS_DOWN;
krt_sys_shutdown(p);
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rem_node(&p->krt_node);
return PS_DOWN;
}
static int
krt_reconfigure(struct proto *p, struct proto_config *CF)
{
struct krt_config *o = (void *) p->cf;
struct krt_config *n = (void *) CF;
if (!proto_configure_channel(p, &p->main_channel, proto_cf_main_channel(CF)))
return 0;
if (!krt_sys_reconfigure((struct krt_proto *) p, n, o))
return 0;
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/* persist, graceful restart need not be the same */
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return o->scan_time == n->scan_time && o->learn == n->learn;
}
struct proto_config *
krt_init_config(int class)
{
#ifndef CONFIG_MULTIPLE_TABLES
if (krt_cf)
cf_error("Kernel protocol already defined");
#endif
krt_cf = (struct krt_config *) proto_config_new(&proto_unix_kernel, class);
2017-06-14 19:15:35 +08:00
krt_cf->scan_time = 60 S;
krt_sys_init_config(krt_cf);
return (struct proto_config *) krt_cf;
}
static void
krt_copy_config(struct proto_config *dest, struct proto_config *src)
{
struct krt_config *d = (struct krt_config *) dest;
struct krt_config *s = (struct krt_config *) src;
/* Fix sysdep parts */
krt_sys_copy_config(d, s);
}
static int
krt_get_attr(eattr *a, byte *buf, int buflen)
{
switch (a->id)
{
case EA_KRT_SOURCE:
bsprintf(buf, "source");
return GA_NAME;
2012-03-23 08:17:02 +08:00
case EA_KRT_METRIC:
bsprintf(buf, "metric");
return GA_NAME;
default:
return krt_sys_get_attr(a, buf, buflen);
}
}
#ifdef CONFIG_IP6_SADR_KERNEL
#define MAYBE_IP6_SADR NB_IP6_SADR
#else
#define MAYBE_IP6_SADR 0
#endif
#ifdef HAVE_MPLS_KERNEL
#define MAYBE_MPLS NB_MPLS
#else
#define MAYBE_MPLS 0
#endif
struct protocol proto_unix_kernel = {
.name = "Kernel",
.template = "kernel%d",
.class = PROTOCOL_KERNEL,
.preference = DEF_PREF_INHERITED,
.channel_mask = NB_IP | MAYBE_IP6_SADR | MAYBE_MPLS,
.proto_size = sizeof(struct krt_proto),
.config_size = sizeof(struct krt_config),
.preconfig = krt_preconfig,
.postconfig = krt_postconfig,
.init = krt_init,
.start = krt_start,
.shutdown = krt_shutdown,
.reconfigure = krt_reconfigure,
.copy_config = krt_copy_config,
.get_attr = krt_get_attr,
#ifdef KRT_ALLOW_LEARN
.dump = krt_dump,
.dump_attrs = krt_dump_attrs,
#endif
};