contiki/core/net/ipv6/uip-ds6-route.c
Timofei Istomin 65ef375bdb Re-create a routing table entry if the next hop is changed.
The next-hop address did not get updated in the routing table
in case an entry for the destination already existed.

This patch resolves the issue by removing the entry and
having it re-created from scratch.

The issue causes a routing error triggering reconstruction of
the DODAG through version increase.

In case of somewhat frequent downward traffic in not (yet) stabilized DODAG
a vicious circle is formed: unstable topology means churn, downward
routing under churn causes reconstruction of DODAG. In this situation
the network does not have chance to stabilize.

We encountered a constant churn caused by this bug
in a network of 50 nodes and a periodic traffic (a packet every 5
seconds) generated at the root.

More info and a PCAP demonstrating the issue can be found here:
https://github.com/contiki-os/contiki/issues/496
2014-06-13 13:31:15 +02:00

629 lines
19 KiB
C

/*
* Copyright (c) 2012, Thingsquare, http://www.thingsquare.com/.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "net/ipv6/uip-ds6.h"
#include "net/ip/uip.h"
#include "lib/list.h"
#include "lib/memb.h"
#include "net/nbr-table.h"
#if UIP_CONF_IPV6
#include <string.h>
/* The nbr_routes holds a neighbor table to be able to maintain
information about what routes go through what neighbor. This
neighbor table is registered with the central nbr-table repository
so that it will be maintained along with the rest of the neighbor
tables in the system. */
NBR_TABLE(struct uip_ds6_route_neighbor_routes, nbr_routes);
MEMB(neighborroutememb, struct uip_ds6_route_neighbor_route, UIP_DS6_ROUTE_NB);
/* Each route is repressented by a uip_ds6_route_t structure and
memory for each route is allocated from the routememb memory
block. These routes are maintained on the routelist. */
LIST(routelist);
MEMB(routememb, uip_ds6_route_t, UIP_DS6_ROUTE_NB);
/* Default routes are held on the defaultrouterlist and their
structures are allocated from the defaultroutermemb memory block.*/
LIST(defaultrouterlist);
MEMB(defaultroutermemb, uip_ds6_defrt_t, UIP_DS6_DEFRT_NB);
#if UIP_DS6_NOTIFICATIONS
LIST(notificationlist);
#endif
static int num_routes = 0;
#undef DEBUG
#define DEBUG DEBUG_NONE
#include "net/ip/uip-debug.h"
static void rm_routelist_callback(nbr_table_item_t *ptr);
/*---------------------------------------------------------------------------*/
#if DEBUG != DEBUG_NONE
static void
assert_nbr_routes_list_sane(void)
{
uip_ds6_route_t *r;
int count;
/* Check if the route list has an infinite loop. */
for(r = uip_ds6_route_head(),
count = 0;
r != NULL &&
count < UIP_DS6_ROUTE_NB * 2;
r = uip_ds6_route_next(r),
count++);
if(count > UIP_DS6_ROUTE_NB) {
printf("uip-ds6-route.c: assert_nbr_routes_list_sane route list is in infinite loop\n");
}
/* Make sure that the route list has as many entries as the
num_routes vairable. */
if(count < num_routes) {
printf("uip-ds6-route.c: assert_nbr_routes_list_sane too few entries on route list: should be %d, is %d, max %d\n",
num_routes, count, UIP_CONF_MAX_ROUTES);
}
}
#endif /* DEBUG != DEBUG_NONE */
/*---------------------------------------------------------------------------*/
#if UIP_DS6_NOTIFICATIONS
static void
call_route_callback(int event, uip_ipaddr_t *route,
uip_ipaddr_t *nexthop)
{
int num;
struct uip_ds6_notification *n;
for(n = list_head(notificationlist);
n != NULL;
n = list_item_next(n)) {
if(event == UIP_DS6_NOTIFICATION_DEFRT_ADD ||
event == UIP_DS6_NOTIFICATION_DEFRT_RM) {
num = list_length(defaultrouterlist);
} else {
num = num_routes;
}
n->callback(event, route, nexthop, num);
}
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_notification_add(struct uip_ds6_notification *n,
uip_ds6_notification_callback c)
{
if(n != NULL && c != NULL) {
n->callback = c;
list_add(notificationlist, n);
}
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_notification_rm(struct uip_ds6_notification *n)
{
list_remove(notificationlist, n);
}
#endif
/*---------------------------------------------------------------------------*/
void
uip_ds6_route_init(void)
{
memb_init(&routememb);
list_init(routelist);
nbr_table_register(nbr_routes,
(nbr_table_callback *)rm_routelist_callback);
memb_init(&defaultroutermemb);
list_init(defaultrouterlist);
#if UIP_DS6_NOTIFICATIONS
list_init(notificationlist);
#endif
}
/*---------------------------------------------------------------------------*/
static uip_lladdr_t *
uip_ds6_route_nexthop_lladdr(uip_ds6_route_t *route)
{
if(route != NULL) {
return (uip_lladdr_t *)nbr_table_get_lladdr(nbr_routes,
route->neighbor_routes);
} else {
return NULL;
}
}
/*---------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_ds6_route_nexthop(uip_ds6_route_t *route)
{
if(route != NULL) {
return uip_ds6_nbr_ipaddr_from_lladdr(uip_ds6_route_nexthop_lladdr(route));
} else {
return NULL;
}
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_head(void)
{
return list_head(routelist);
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_next(uip_ds6_route_t *r)
{
if(r != NULL) {
uip_ds6_route_t *n = list_item_next(r);
return n;
}
return NULL;
}
/*---------------------------------------------------------------------------*/
int
uip_ds6_route_num_routes(void)
{
return num_routes;
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_lookup(uip_ipaddr_t *addr)
{
uip_ds6_route_t *r;
uip_ds6_route_t *found_route;
uint8_t longestmatch;
PRINTF("uip-ds6-route: Looking up route for ");
PRINT6ADDR(addr);
PRINTF("\n");
found_route = NULL;
longestmatch = 0;
for(r = uip_ds6_route_head();
r != NULL;
r = uip_ds6_route_next(r)) {
if(r->length >= longestmatch &&
uip_ipaddr_prefixcmp(addr, &r->ipaddr, r->length)) {
longestmatch = r->length;
found_route = r;
}
}
if(found_route != NULL) {
PRINTF("uip-ds6-route: Found route: ");
PRINT6ADDR(addr);
PRINTF(" via ");
PRINT6ADDR(uip_ds6_route_nexthop(found_route));
PRINTF("\n");
} else {
PRINTF("uip-ds6-route: No route found\n");
}
if(found_route != NULL) {
/* If we found a route, we put it at the end of the routeslist
list. The list is ordered by how recently we looked them up:
the least recently used route will be at the start of the
list. */
list_remove(routelist, found_route);
list_add(routelist, found_route);
}
return found_route;
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_add(uip_ipaddr_t *ipaddr, uint8_t length,
uip_ipaddr_t *nexthop)
{
uip_ds6_route_t *r;
struct uip_ds6_route_neighbor_route *nbrr;
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
/* Get link-layer address of next hop, make sure it is in neighbor table */
const uip_lladdr_t *nexthop_lladdr = uip_ds6_nbr_lladdr_from_ipaddr(nexthop);
if(nexthop_lladdr == NULL) {
PRINTF("uip_ds6_route_add: neighbor link-local address unknown for ");
PRINT6ADDR(nexthop);
PRINTF("\n");
return NULL;
}
/* First make sure that we don't add a route twice. If we find an
existing route for our destination, we'll delete the old
one first. */
r = uip_ds6_route_lookup(ipaddr);
if(r != NULL) {
PRINTF("uip_ds6_route_add: old route for ");
PRINT6ADDR(ipaddr);
PRINTF(" found, deleting it\n");
uip_ds6_route_rm(r);
}
{
struct uip_ds6_route_neighbor_routes *routes;
/* If there is no routing entry, create one. We first need to
check if we have room for this route. If not, we remove the
least recently used one we have. */
if(uip_ds6_route_num_routes() == UIP_DS6_ROUTE_NB) {
/* Removing the oldest route entry from the route table. The
least recently used route is the first route on the list. */
uip_ds6_route_t *oldest;
oldest = uip_ds6_route_head();
PRINTF("uip_ds6_route_add: dropping route to ");
PRINT6ADDR(&oldest->ipaddr);
PRINTF("\n");
uip_ds6_route_rm(oldest);
}
/* Every neighbor on our neighbor table holds a struct
uip_ds6_route_neighbor_routes which holds a list of routes that
go through the neighbor. We add our route entry to this list.
We first check to see if we already have this neighbor in our
nbr_route table. If so, the neighbor already has a route entry
list.
*/
routes = nbr_table_get_from_lladdr(nbr_routes,
(linkaddr_t *)nexthop_lladdr);
if(routes == NULL) {
/* If the neighbor did not have an entry in our neighbor table,
we create one. The nbr_table_add_lladdr() function returns a
pointer to a pointer that we may use for our own purposes. We
initialize this pointer with the list of routing entries that
are attached to this neighbor. */
routes = nbr_table_add_lladdr(nbr_routes,
(linkaddr_t *)nexthop_lladdr);
if(routes == NULL) {
/* This should not happen, as we explicitly deallocated one
route table entry above. */
PRINTF("uip_ds6_route_add: could not allocate neighbor table entry\n");
return NULL;
}
LIST_STRUCT_INIT(routes, route_list);
}
/* Allocate a routing entry and populate it. */
r = memb_alloc(&routememb);
if(r == NULL) {
/* This should not happen, as we explicitly deallocated one
route table entry above. */
PRINTF("uip_ds6_route_add: could not allocate route\n");
return NULL;
}
list_add(routelist, r);
nbrr = memb_alloc(&neighborroutememb);
if(nbrr == NULL) {
/* This should not happen, as we explicitly deallocated one
route table entry above. */
PRINTF("uip_ds6_route_add: could not allocate neighbor route list entry\n");
memb_free(&routememb, r);
return NULL;
}
nbrr->route = r;
/* Add the route to this neighbor */
list_add(routes->route_list, nbrr);
r->neighbor_routes = routes;
num_routes++;
PRINTF("uip_ds6_route_add num %d\n", num_routes);
}
uip_ipaddr_copy(&(r->ipaddr), ipaddr);
r->length = length;
#ifdef UIP_DS6_ROUTE_STATE_TYPE
memset(&r->state, 0, sizeof(UIP_DS6_ROUTE_STATE_TYPE));
#endif
PRINTF("uip_ds6_route_add: adding route: ");
PRINT6ADDR(ipaddr);
PRINTF(" via ");
PRINT6ADDR(nexthop);
PRINTF("\n");
ANNOTATE("#L %u 1;blue\n", nexthop->u8[sizeof(uip_ipaddr_t) - 1]);
#if UIP_DS6_NOTIFICATIONS
call_route_callback(UIP_DS6_NOTIFICATION_ROUTE_ADD, ipaddr, nexthop);
#endif
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
return r;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_route_rm(uip_ds6_route_t *route)
{
struct uip_ds6_route_neighbor_route *neighbor_route;
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
if(route != NULL && route->neighbor_routes != NULL) {
PRINTF("uip_ds6_route_rm: removing route: ");
PRINT6ADDR(&route->ipaddr);
PRINTF("\n");
/* Remove the neighbor from the route list */
list_remove(routelist, route);
/* Find the corresponding neighbor_route and remove it. */
for(neighbor_route = list_head(route->neighbor_routes->route_list);
neighbor_route != NULL && neighbor_route->route != route;
neighbor_route = list_item_next(neighbor_route));
if(neighbor_route == NULL) {
PRINTF("uip_ds6_route_rm: neighbor_route was NULL for ");
uip_debug_ipaddr_print(&route->ipaddr);
PRINTF("\n");
}
list_remove(route->neighbor_routes->route_list, neighbor_route);
if(list_head(route->neighbor_routes->route_list) == NULL) {
/* If this was the only route using this neighbor, remove the
neibhor from the table */
PRINTF("uip_ds6_route_rm: removing neighbor too\n");
nbr_table_remove(nbr_routes, route->neighbor_routes->route_list);
}
memb_free(&routememb, route);
memb_free(&neighborroutememb, neighbor_route);
num_routes--;
PRINTF("uip_ds6_route_rm num %d\n", num_routes);
#if UIP_DS6_NOTIFICATIONS
call_route_callback(UIP_DS6_NOTIFICATION_ROUTE_RM,
&route->ipaddr, uip_ds6_route_nexthop(route));
#endif
#if 0 //(DEBUG & DEBUG_ANNOTATE) == DEBUG_ANNOTATE
/* we need to check if this was the last route towards "nexthop" */
/* if so - remove that link (annotation) */
uip_ds6_route_t *r;
for(r = uip_ds6_route_head();
r != NULL;
r = uip_ds6_route_next(r)) {
uip_ipaddr_t *nextr, *nextroute;
nextr = uip_ds6_route_nexthop(r);
nextroute = uip_ds6_route_nexthop(route);
if(nextr != NULL &&
nextroute != NULL &&
uip_ipaddr_cmp(nextr, nextroute)) {
/* we found another link using the specific nexthop, so keep the #L */
return;
}
}
ANNOTATE("#L %u 0\n", uip_ds6_route_nexthop(route)->u8[sizeof(uip_ipaddr_t) - 1]);
#endif
}
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
return;
}
/*---------------------------------------------------------------------------*/
static void
rm_routelist(struct uip_ds6_route_neighbor_routes *routes)
{
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
PRINTF("uip_ds6_route_rm_routelist\n");
if(routes != NULL && routes->route_list != NULL) {
struct uip_ds6_route_neighbor_route *r;
r = list_head(routes->route_list);
while(r != NULL) {
uip_ds6_route_rm(r->route);
r = list_head(routes->route_list);
}
nbr_table_remove(nbr_routes, routes);
}
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
}
/*---------------------------------------------------------------------------*/
static void
rm_routelist_callback(nbr_table_item_t *ptr)
{
rm_routelist((struct uip_ds6_route_neighbor_routes *)ptr);
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_route_rm_by_nexthop(uip_ipaddr_t *nexthop)
{
/* Get routing entry list of this neighbor */
const uip_lladdr_t *nexthop_lladdr;
struct uip_ds6_route_neighbor_routes *routes;
nexthop_lladdr = uip_ds6_nbr_lladdr_from_ipaddr(nexthop);
routes = nbr_table_get_from_lladdr(nbr_routes,
(linkaddr_t *)nexthop_lladdr);
rm_routelist(routes);
}
/*---------------------------------------------------------------------------*/
uip_ds6_defrt_t *
uip_ds6_defrt_add(uip_ipaddr_t *ipaddr, unsigned long interval)
{
uip_ds6_defrt_t *d;
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
PRINTF("uip_ds6_defrt_add\n");
d = uip_ds6_defrt_lookup(ipaddr);
if(d == NULL) {
d = memb_alloc(&defaultroutermemb);
if(d == NULL) {
PRINTF("uip_ds6_defrt_add: could not add default route to ");
PRINT6ADDR(ipaddr);
PRINTF(", out of memory\n");
return NULL;
} else {
PRINTF("uip_ds6_defrt_add: adding default route to ");
PRINT6ADDR(ipaddr);
PRINTF("\n");
}
list_push(defaultrouterlist, d);
}
uip_ipaddr_copy(&d->ipaddr, ipaddr);
if(interval != 0) {
stimer_set(&d->lifetime, interval);
d->isinfinite = 0;
} else {
d->isinfinite = 1;
}
ANNOTATE("#L %u 1\n", ipaddr->u8[sizeof(uip_ipaddr_t) - 1]);
#if UIP_DS6_NOTIFICATIONS
call_route_callback(UIP_DS6_NOTIFICATION_DEFRT_ADD, ipaddr, ipaddr);
#endif
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
return d;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_defrt_rm(uip_ds6_defrt_t *defrt)
{
uip_ds6_defrt_t *d;
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
/* Make sure that the defrt is in the list before we remove it. */
for(d = list_head(defaultrouterlist);
d != NULL;
d = list_item_next(d)) {
if(d == defrt) {
PRINTF("Removing default route\n");
list_remove(defaultrouterlist, defrt);
memb_free(&defaultroutermemb, defrt);
ANNOTATE("#L %u 0\n", defrt->ipaddr.u8[sizeof(uip_ipaddr_t) - 1]);
#if UIP_DS6_NOTIFICATIONS
call_route_callback(UIP_DS6_NOTIFICATION_DEFRT_RM,
&defrt->ipaddr, &defrt->ipaddr);
#endif
return;
}
}
#if DEBUG != DEBUG_NONE
assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
}
/*---------------------------------------------------------------------------*/
uip_ds6_defrt_t *
uip_ds6_defrt_lookup(uip_ipaddr_t *ipaddr)
{
uip_ds6_defrt_t *d;
for(d = list_head(defaultrouterlist);
d != NULL;
d = list_item_next(d)) {
if(uip_ipaddr_cmp(&d->ipaddr, ipaddr)) {
return d;
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_ds6_defrt_choose(void)
{
uip_ds6_defrt_t *d;
uip_ds6_nbr_t *bestnbr;
uip_ipaddr_t *addr;
addr = NULL;
for(d = list_head(defaultrouterlist);
d != NULL;
d = list_item_next(d)) {
PRINTF("Defrt, IP address ");
PRINT6ADDR(&d->ipaddr);
PRINTF("\n");
bestnbr = uip_ds6_nbr_lookup(&d->ipaddr);
if(bestnbr != NULL && bestnbr->state != NBR_INCOMPLETE) {
PRINTF("Defrt found, IP address ");
PRINT6ADDR(&d->ipaddr);
PRINTF("\n");
return &d->ipaddr;
} else {
addr = &d->ipaddr;
PRINTF("Defrt INCOMPLETE found, IP address ");
PRINT6ADDR(&d->ipaddr);
PRINTF("\n");
}
}
return addr;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_defrt_periodic(void)
{
uip_ds6_defrt_t *d;
d = list_head(defaultrouterlist);
while(d != NULL) {
if(!d->isinfinite &&
stimer_expired(&d->lifetime)) {
PRINTF("uip_ds6_defrt_periodic: defrt lifetime expired\n");
uip_ds6_defrt_rm(d);
d = list_head(defaultrouterlist);
} else {
d = list_item_next(d);
}
}
}
/*---------------------------------------------------------------------------*/
#endif /* UIP_CONF_IPV6 */