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/*
* BIRD -- Linux Routing Table Scanning
*
* (c) 1998 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <net/route.h>
#define LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "lib/timer.h"
#include "lib/unix.h"
#include "lib/krt.h"
#define SCANOPT struct krt_scan_params *p = &x->scanopt
static int krt_scan_fd = -1;
/* FIXME: Filtering */
static void
krt_magic_route(struct krt_proto *p, net *net, ip_addr gw)
{
neighbor *ng;
rta a, *t;
rte *e;
ng = neigh_find(&p->p, &gw, 0);
if (!ng)
{
log(L_ERR "Kernel told us to use non-neighbor %I for %I/%d\n", gw, net->n.prefix, net->n.pxlen);
return;
}
a.proto = &p->p;
a.source = RTS_INHERIT;
a.scope = SCOPE_UNIVERSE;
a.cast = RTC_UNICAST;
a.dest = RTD_ROUTER;
a.tos = 0;
a.flags = 0;
a.gw = gw;
a.from = IPA_NONE;
a.iface = ng->iface;
a.attrs = NULL;
t = rta_lookup(&a);
e = rte_get_temp(t);
e->net = net;
rte_update(net, &p->p, e);
}
static void
krt_parse_entry(byte *e, struct krt_proto *p)
{
u32 dest0, gw0, mask0;
ip_addr dest, gw, mask;
unsigned int flags;
int masklen;
net *net;
byte *iface = e;
if (sscanf(e, "%*s\t%x\t%x\t%x\t%*d\t%*d\t%*d\t%x\t", &dest0, &gw0, &flags, &mask0) != 4)
{
log(L_ERR "krt read: unable to parse `%s'", e);
return;
}
while (*e != '\t')
e++;
*e = 0;
dest = ipa_from_u32(dest0);
ipa_ntoh(dest);
gw = ipa_from_u32(gw0);
ipa_ntoh(gw);
mask = ipa_from_u32(mask0);
ipa_ntoh(mask);
if ((masklen = ipa_mklen(mask)) < 0)
{
log(L_ERR "krt read: invalid netmask %08x", mask0);
return;
}
DBG("Got %I/%d via %I flags %x\n", dest, masklen, gw, flags);
if (!(flags & RTF_UP))
return;
if (flags & RTF_HOST)
masklen = 32;
if (flags & (RTF_DYNAMIC | RTF_MODIFIED)) /* Redirect route */
{
log(L_WARN "krt: Ignoring redirect to %I/%d via %I", dest, masklen, gw);
return;
}
net = net_get(&master_table, 0, dest, masklen);
if (net->routes)
{
rte *e = net->routes;
rta *a = e->attrs;
int ok;
switch (a->dest)
{
case RTD_ROUTER:
ok = (flags & RTF_GATEWAY) && ipa_equal(gw, a->gw);
break;
case RTD_DEVICE:
#ifdef CONFIG_AUTO_ROUTES
ok = 1;
/* FIXME: What about static interface routes? */
#else
ok = !(flags & RTF_GATEWAY) && !strcmp(iface, a->iface->name);
#endif
break;
case RTD_UNREACHABLE:
ok = flags & RTF_REJECT;
break;
default:
ok = 0;
}
net->n.flags |= ok ? KRF_SEEN : KRF_UPDATE;
}
else
{
#ifdef CONFIG_AUTO_ROUTES
if (!(flags & RTF_GATEWAY)) /* It's a device route */
return;
#endif
DBG("krt_parse_entry: kernel reporting unknown route %I/%d\n", dest, masklen);
if (p->scanopt.learn)
{
if (flags & RTF_GATEWAY)
krt_magic_route(p, net, gw);
}
net->n.flags |= KRF_UPDATE;
}
}
static int
krt_scan_proc(struct krt_proto *p)
{
byte buf[32768];
int l, seen_hdr;
DBG("Scanning kernel table...\n");
if (krt_scan_fd < 0)
{
krt_scan_fd = open("/proc/net/route", O_RDONLY);
if (krt_scan_fd < 0)
die("/proc/net/route: %m");
}
else if (lseek(krt_scan_fd, 0, SEEK_SET) < 0)
{
log(L_ERR "krt seek: %m");
return 0;
}
seen_hdr = 0;
while ((l = read(krt_scan_fd, buf, sizeof(buf))) > 0)
{
byte *z = buf;
if (l & 127)
{
log(L_ERR "krt read: misaligned entry: l=%d", l);
return 0;
}
while (l >= 128)
{
if (seen_hdr++)
krt_parse_entry(z, p);
z += 128;
l -= 128;
}
}
if (l < 0)
{
log(L_ERR "krt read: %m");
return 0;
}
DBG("KRT scan done, seen %d lines\n", seen_hdr);
return 1;
}
static void
krt_prune(void)
{
struct rtable *t = &master_table;
struct fib_node *f;
DBG("Pruning routes...\n");
while (t && t->tos)
t = t->sibling;
if (!t)
return;
FIB_WALK(&t->fib, f)
{
net *n = (net *) f;
switch (f->flags)
{
case KRF_UPDATE:
DBG("krt_prune: removing %I/%d\n", n->n.prefix, n->n.pxlen);
krt_remove_route(n, NULL);
/* Fall-thru */
case 0:
if (n->routes)
{
DBG("krt_prune: reinstalling %I/%d\n", n->n.prefix, n->n.pxlen);
krt_add_route(n, n->routes);
}
break;
case KRF_SEEN:
break;
default:
die("krt_prune: invalid route status");
}
f->flags = 0;
}
FIB_WALK_END;
}
static void
krt_scan_fire(timer *t)
{
struct krt_proto *p = t->data;
if (krt_scan_proc(p))
krt_prune();
}
void
krt_scan_preconfig(struct krt_proto *x)
{
SCANOPT;
p->recurrence = 60;
p->learn = 0;
}
void
krt_scan_start(struct krt_proto *x)
{
SCANOPT;
timer *t = tm_new(x->p.pool);
p->timer = t;
t->hook = krt_scan_fire;
t->data = x;
t->recurrent = p->recurrence;
krt_scan_fire(t);
if (t->recurrent)
tm_start(t, t->recurrent);
}
void
krt_scan_shutdown(struct krt_proto *x)
{
SCANOPT;
tm_stop(p->timer);
/* FIXME: Remove all krt's? */
}
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