bird/sysdep/linux/krt-scan.c
Martin Mares 2d14045224 Rewrote the kernel syncer. The old layering was horrible.
The new kernel syncer is cleanly split between generic UNIX module
and OS dependent submodules:

  -  krt.c (the generic part)
  -  krt-iface (low-level functions for interface handling)
  -  krt-scan (low-level functions for routing table scanning)
  -  krt-set (low-level functions for setting of kernel routes)

krt-set and krt-iface are common for all BSD-like Unices, krt-scan is heavily
system dependent (most Unices require /dev/kmem parsing, Linux uses /proc),
Netlink substitues all three modules.

We expect each UNIX port supports kernel routing table scanning, kernel
interface table scanning, kernel route manipulation and possibly also
asynchronous event notifications (new route, interface state change;
not implemented yet) and build the KRT protocol on the top of these
primitive operations.
1999-03-03 19:49:56 +00:00

190 lines
3.7 KiB
C

/*
* BIRD -- Linux Routing Table Scanning
*
* (c) 1998--1999 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 <ctype.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"
static int krt_scan_fd = -1;
struct iface *
krt_temp_iface(struct krt_proto *p, char *name)
{
struct iface *i;
WALK_LIST(i, p->scan.temp_ifs)
if (!strcmp(i->name, name))
return i;
i = mb_alloc(p->p.pool, sizeof(struct iface));
bzero(i, sizeof(*i));
strcpy(i->name, name);
add_tail(&p->scan.temp_ifs, &i->n);
return i;
}
static void
krt_parse_entry(byte *ent, struct krt_proto *p)
{
u32 dest0, gw0, mask0;
ip_addr dest, gw, mask;
unsigned int flags;
int masklen;
net *net;
byte *iface = ent;
rta a;
rte *e;
if (sscanf(ent, "%*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'", ent);
return;
}
while (*ent != '\t')
ent++;
*ent = 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))
{
DBG("Down.\n");
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);
a.proto = &p->p;
a.source = RTS_INHERIT;
a.scope = SCOPE_UNIVERSE;
a.cast = RTC_UNICAST;
a.tos = a.flags = a.aflags = 0;
a.from = IPA_NONE;
a.iface = NULL;
a.attrs = NULL;
if (flags & RTF_GATEWAY)
{
neighbor *ng = neigh_find(&p->p, &gw, 0);
if (ng)
a.iface = ng->iface;
else
/* FIXME: Remove this warning? */
log(L_WARN "Kernel told us to use non-neighbor %I for %I/%d", gw, net->n.prefix, net->n.pxlen);
a.dest = RTD_ROUTER;
a.gw = gw;
}
else if (flags & RTF_REJECT)
{
a.dest = RTD_UNREACHABLE;
a.gw = IPA_NONE;
}
else if (isalpha(iface[0]))
{
a.dest = RTD_DEVICE;
a.gw = IPA_NONE;
a.iface = krt_temp_iface(p, iface);
}
else
{
log(L_WARN "Kernel reporting unknown route type to %I/%d", net->n.prefix, net->n.pxlen);
return;
}
e = rte_get_temp(&a);
e->net = net;
krt_got_route(p, e);
}
void
krt_scan_fire(struct krt_proto *p)
{
byte buf[32768];
int l, seen_hdr;
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;
}
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;
}
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;
}
DBG("KRT scan done, seen %d lines\n", seen_hdr);
}
void
krt_scan_preconfig(struct krt_config *c)
{
}
void
krt_scan_start(struct krt_proto *x)
{
init_list(&x->scan.temp_ifs);
}
void
krt_scan_shutdown(struct krt_proto *x)
{
}