summaryrefslogtreecommitdiff
path: root/babeld/neighbour.c
diff options
context:
space:
mode:
Diffstat (limited to 'babeld/neighbour.c')
-rw-r--r--babeld/neighbour.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/babeld/neighbour.c b/babeld/neighbour.c
new file mode 100644
index 00000000..5a327dfe
--- /dev/null
+++ b/babeld/neighbour.c
@@ -0,0 +1,343 @@
+/*
+ * This file is free software: you may copy, redistribute and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+Copyright (c) 2007, 2008 by Juliusz Chroboczek
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include <zebra.h>
+#include "if.h"
+
+#include "babel_main.h"
+#include "babeld.h"
+#include "util.h"
+#include "babel_interface.h"
+#include "neighbour.h"
+#include "source.h"
+#include "route.h"
+#include "message.h"
+#include "resend.h"
+
+struct neighbour *neighs = NULL;
+
+static struct neighbour *
+find_neighbour_nocreate(const unsigned char *address, struct interface *ifp)
+{
+ struct neighbour *neigh;
+ FOR_ALL_NEIGHBOURS(neigh) {
+ if(memcmp(address, neigh->address, 16) == 0 &&
+ neigh->ifp == ifp)
+ return neigh;
+ }
+ return NULL;
+}
+
+void
+flush_neighbour(struct neighbour *neigh)
+{
+ flush_neighbour_routes(neigh);
+ if(unicast_neighbour == neigh)
+ flush_unicast(1);
+ flush_resends(neigh);
+
+ if(neighs == neigh) {
+ neighs = neigh->next;
+ } else {
+ struct neighbour *previous = neighs;
+ while(previous->next != neigh)
+ previous = previous->next;
+ previous->next = neigh->next;
+ }
+ free(neigh);
+}
+
+struct neighbour *
+find_neighbour(const unsigned char *address, struct interface *ifp)
+{
+ struct neighbour *neigh;
+ const struct timeval zero = {0, 0};
+
+ neigh = find_neighbour_nocreate(address, ifp);
+ if(neigh)
+ return neigh;
+
+ debugf(BABEL_DEBUG_COMMON,"Creating neighbour %s on %s.",
+ format_address(address), ifp->name);
+
+ neigh = malloc(sizeof(struct neighbour));
+ if(neigh == NULL) {
+ zlog_err("malloc(neighbour): %s", safe_strerror(errno));
+ return NULL;
+ }
+
+ neigh->hello_seqno = -1;
+ memcpy(neigh->address, address, 16);
+ neigh->reach = 0;
+ neigh->txcost = INFINITY;
+ neigh->ihu_time = babel_now;
+ neigh->hello_time = zero;
+ neigh->hello_interval = 0;
+ neigh->ihu_interval = 0;
+ neigh->ifp = ifp;
+ neigh->next = neighs;
+ neighs = neigh;
+ send_hello(ifp);
+ return neigh;
+}
+
+/* Recompute a neighbour's rxcost. Return true if anything changed.
+ This does not call local_notify_neighbour, see update_neighbour_metric. */
+int
+update_neighbour(struct neighbour *neigh, int hello, int hello_interval)
+{
+ int missed_hellos;
+ int rc = 0;
+
+ if(hello < 0) {
+ if(neigh->hello_interval <= 0)
+ return rc;
+ missed_hellos =
+ ((int)timeval_minus_msec(&babel_now, &neigh->hello_time) -
+ neigh->hello_interval * 7) /
+ (neigh->hello_interval * 10);
+ if(missed_hellos <= 0)
+ return rc;
+ timeval_add_msec(&neigh->hello_time, &neigh->hello_time,
+ missed_hellos * neigh->hello_interval * 10);
+ } else {
+ if(neigh->hello_seqno >= 0 && neigh->reach > 0) {
+ missed_hellos = seqno_minus(hello, neigh->hello_seqno) - 1;
+ if(missed_hellos < -8) {
+ /* Probably a neighbour that rebooted and lost its seqno.
+ Reboot the universe. */
+ neigh->reach = 0;
+ missed_hellos = 0;
+ rc = 1;
+ } else if(missed_hellos < 0) {
+ if(hello_interval > neigh->hello_interval) {
+ /* This neighbour has increased its hello interval,
+ and we didn't notice. */
+ neigh->reach <<= -missed_hellos;
+ missed_hellos = 0;
+ } else {
+ /* Late hello. Probably due to the link layer buffering
+ packets during a link outage. Ignore it, but reset
+ the expected seqno. */
+ neigh->hello_seqno = hello;
+ hello = -1;
+ missed_hellos = 0;
+ }
+ rc = 1;
+ }
+ } else {
+ missed_hellos = 0;
+ }
+ neigh->hello_time = babel_now;
+ neigh->hello_interval = hello_interval;
+ }
+
+ if(missed_hellos > 0) {
+ neigh->reach >>= missed_hellos;
+ neigh->hello_seqno = seqno_plus(neigh->hello_seqno, missed_hellos);
+ missed_hellos = 0;
+ rc = 1;
+ }
+
+ if(hello >= 0) {
+ neigh->hello_seqno = hello;
+ neigh->reach >>= 1;
+ neigh->reach |= 0x8000;
+ if((neigh->reach & 0xFC00) != 0xFC00)
+ rc = 1;
+ }
+
+ /* Make sure to give neighbours some feedback early after association */
+ if((neigh->reach & 0xBF00) == 0x8000) {
+ /* A new neighbour */
+ send_hello(neigh->ifp);
+ } else {
+ /* Don't send hellos, in order to avoid a positive feedback loop. */
+ int a = (neigh->reach & 0xC000);
+ int b = (neigh->reach & 0x3000);
+ if((a == 0xC000 && b == 0) || (a == 0 && b == 0x3000)) {
+ /* Reachability is either 1100 or 0011 */
+ send_self_update(neigh->ifp);
+ }
+ }
+
+ if((neigh->reach & 0xFC00) == 0xC000) {
+ /* This is a newish neighbour, let's request a full route dump.
+ We ought to avoid this when the network is dense */
+ send_unicast_request(neigh, NULL, 0);
+ send_ihu(neigh, NULL);
+ }
+ return rc;
+}
+
+static int
+reset_txcost(struct neighbour *neigh)
+{
+ unsigned delay;
+
+ delay = timeval_minus_msec(&babel_now, &neigh->ihu_time);
+
+ if(neigh->ihu_interval > 0 && delay < neigh->ihu_interval * 10U * 3U)
+ return 0;
+
+ /* If we're losing a lot of packets, we probably lost an IHU too */
+ if(delay >= 180000 || (neigh->reach & 0xFFF0) == 0 ||
+ (neigh->ihu_interval > 0 &&
+ delay >= neigh->ihu_interval * 10U * 10U)) {
+ neigh->txcost = INFINITY;
+ neigh->ihu_time = babel_now;
+ return 1;
+ }
+
+ return 0;
+}
+
+unsigned
+neighbour_txcost(struct neighbour *neigh)
+{
+ return neigh->txcost;
+}
+
+unsigned
+check_neighbours()
+{
+ struct neighbour *neigh;
+ int changed, rc;
+ unsigned msecs = 50000;
+
+ debugf(BABEL_DEBUG_COMMON,"Checking neighbours.");
+
+ neigh = neighs;
+ while(neigh) {
+ changed = update_neighbour(neigh, -1, 0);
+
+ if(neigh->reach == 0 ||
+ neigh->hello_time.tv_sec > babel_now.tv_sec || /* clock stepped */
+ timeval_minus_msec(&babel_now, &neigh->hello_time) > 300000) {
+ struct neighbour *old = neigh;
+ neigh = neigh->next;
+ flush_neighbour(old);
+ continue;
+ }
+
+ rc = reset_txcost(neigh);
+ changed = changed || rc;
+
+ update_neighbour_metric(neigh, changed);
+
+ if(neigh->hello_interval > 0)
+ msecs = MIN(msecs, neigh->hello_interval * 10U);
+ if(neigh->ihu_interval > 0)
+ msecs = MIN(msecs, neigh->ihu_interval * 10U);
+ neigh = neigh->next;
+ }
+
+ return msecs;
+}
+
+unsigned
+neighbour_rxcost(struct neighbour *neigh)
+{
+ unsigned delay;
+ unsigned short reach = neigh->reach;
+
+ delay = timeval_minus_msec(&babel_now, &neigh->hello_time);
+
+ if((reach & 0xFFF0) == 0 || delay >= 180000) {
+ return INFINITY;
+ } else if(babel_get_if_nfo(neigh->ifp)->flags & BABEL_IF_LQ) {
+ int sreach =
+ ((reach & 0x8000) >> 2) +
+ ((reach & 0x4000) >> 1) +
+ (reach & 0x3FFF);
+ /* 0 <= sreach <= 0x7FFF */
+ int cost = (0x8000 * babel_get_if_nfo(neigh->ifp)->cost) / (sreach + 1);
+ /* cost >= interface->cost */
+ if(delay >= 40000)
+ cost = (cost * (delay - 20000) + 10000) / 20000;
+ return MIN(cost, INFINITY);
+ } else {
+ /* To lose one hello is a misfortune, to lose two is carelessness. */
+ if((reach & 0xC000) == 0xC000)
+ return babel_get_if_nfo(neigh->ifp)->cost;
+ else if((reach & 0xC000) == 0)
+ return INFINITY;
+ else if((reach & 0x2000))
+ return babel_get_if_nfo(neigh->ifp)->cost;
+ else
+ return INFINITY;
+ }
+}
+
+unsigned
+neighbour_cost(struct neighbour *neigh)
+{
+ unsigned a, b;
+
+ if(!if_up(neigh->ifp))
+ return INFINITY;
+
+ a = neighbour_txcost(neigh);
+
+ if(a >= INFINITY)
+ return INFINITY;
+
+ b = neighbour_rxcost(neigh);
+ if(b >= INFINITY)
+ return INFINITY;
+
+ if(!(babel_get_if_nfo(neigh->ifp)->flags & BABEL_IF_LQ)
+ || (a < 256 && b < 256)) {
+ return a;
+ } else {
+ /* a = 256/alpha, b = 256/beta, where alpha and beta are the expected
+ probabilities of a packet getting through in the direct and reverse
+ directions. */
+ a = MAX(a, 256);
+ b = MAX(b, 256);
+ /* 1/(alpha * beta), which is just plain ETX. */
+ /* Since a and b are capped to 16 bits, overflow is impossible. */
+ return (a * b + 128) >> 8;
+ }
+}