189 lines
3.5 KiB
C
189 lines
3.5 KiB
C
/*
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* BIRD -- Linux Routing Table Scanning
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*
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* (c) 1998 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include <string.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <net/route.h>
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#define LOCAL_DEBUG
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#include "nest/bird.h"
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#include "nest/route.h"
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#include "nest/protocol.h"
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#include "nest/iface.h"
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#include "lib/timer.h"
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#include "lib/unix.h"
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#include "lib/krt.h"
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#define SCANOPT struct krt_scan_params *p = &x->scanopt
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static int krt_scan_fd = -1;
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static void
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krt_parse_entry(byte *e)
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{
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u32 dest0, gw0, mask0;
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ip_addr dest, gw, mask;
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unsigned int flags;
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int masklen;
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net *net;
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byte *iface = e;
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if (sscanf(e, "%*s\t%x\t%x\t%x\t%*d\t%*d\t%*d\t%x\t", &dest0, &gw0, &flags, &mask0) != 4)
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{
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log(L_ERR "krt read: unable to parse `%s'", e);
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return;
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}
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while (*e != '\t')
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e++;
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*e = 0;
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dest = ipa_from_u32(dest0);
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ipa_ntoh(dest);
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gw = ipa_from_u32(gw0);
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ipa_ntoh(gw);
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mask = ipa_from_u32(mask0);
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ipa_ntoh(mask);
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if ((masklen = ipa_mklen(mask)) < 0)
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{
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log(L_ERR "krt read: invalid netmask %08x", mask0);
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return;
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}
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DBG("Got %I/%d via %I flags %x\n", dest, masklen, gw, flags);
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if (!(flags & RTF_UP))
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return;
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if (flags & RTF_HOST)
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masklen = 32;
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if (flags & (RTF_DYNAMIC | RTF_MODIFIED)) /* Redirect route */
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{
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log(L_WARN "krt: Ignoring redirect to %I/%d via %I", dest, masklen, gw);
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return;
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}
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net = net_get(&master_table, 0, dest, masklen);
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if (net->routes)
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{
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rte *e = net->routes;
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rta *a = e->attrs;
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int ok;
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switch (a->dest)
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{
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case RTD_ROUTER:
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ok = (flags & RTF_GATEWAY) && ipa_equal(gw, a->gw);
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break;
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case RTD_DEVICE:
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#ifdef CONFIG_AUTO_ROUTES
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ok = 1;
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#else
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ok = !(flags & RTF_GATEWAY) && !strcmp(iface, a->iface->name);
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#endif
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break;
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case RTD_UNREACHABLE:
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ok = flags & RTF_REJECT;
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default:
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ok = 0;
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}
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net->n.flags |= ok ? KRF_SEEN : KRF_UPDATE;
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}
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else
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{
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#ifdef CONFIG_AUTO_ROUTES
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if (!(flags & RTF_GATEWAY)) /* It's a device route */
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return;
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#endif
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net->n.flags |= KRF_UPDATE;
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}
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}
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static int
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krt_scan_proc(void)
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{
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byte buf[32768];
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int l, seen_hdr;
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if (krt_scan_fd < 0)
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{
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krt_scan_fd = open("/proc/net/route", O_RDONLY);
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if (krt_scan_fd < 0)
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die("/proc/net/route: %m");
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}
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else if (lseek(krt_scan_fd, 0, SEEK_SET) < 0)
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{
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log(L_ERR "krt seek: %m");
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return 0;
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}
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seen_hdr = 0;
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while ((l = read(krt_scan_fd, buf, sizeof(buf))) > 0)
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{
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byte *z = buf;
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if (l & 127)
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{
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log(L_ERR "krt read: misaligned entry: l=%d", l);
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return 0;
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}
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while (l >= 128)
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{
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if (seen_hdr++)
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krt_parse_entry(z);
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z += 128;
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l -= 128;
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}
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}
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if (l < 0)
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{
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log(L_ERR "krt read: %m");
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return 0;
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}
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DBG("KRT scan done, seen %d lines\n", seen_hdr);
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return 1;
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}
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static void
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krt_scan_fire(timer *t)
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{
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struct krt_proto *x = t->data;
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SCANOPT;
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DBG("Scanning kernel table...\n");
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if (!krt_scan_proc())
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return;
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}
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void
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krt_scan_preconfig(struct krt_proto *x)
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{
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SCANOPT;
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p->recurrence = 10; /* FIXME: use reasonable default value */
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}
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void
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krt_scan_start(struct krt_proto *x)
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{
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SCANOPT;
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timer *t = tm_new(x->p.pool);
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p->timer = t;
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t->hook = krt_scan_fire;
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t->data = x;
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t->recurrent = p->recurrence;
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krt_scan_fire(t);
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if (t->recurrent)
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tm_start(t, t->recurrent);
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}
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void
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krt_scan_shutdown(struct krt_proto *x)
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{
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SCANOPT;
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tm_stop(p->timer);
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}
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