ripd: allow to enable/disable the ECMP feature
Introduce a new command "[no] allow-ecmp" to enable/disable the
ECMP feature in RIP. By default, ECMP is not allowed.
Once ECMP is disabled, only one route entry can exist in the list.
* rip_zebra.c: adjust a debugging information, which shows the number
of nexthops according to whether ECMP is enabled.
* ripd.c: rip_ecmp_add() will reject the new route if ECMP is not
allowed and some entry already exists.
A new configurable command "allow-ecmp" is added to control
whether ECMP is allowed.
When ECMP is disabled, rip_ecmp_disable() is called to
remove the multiple nexthops.
* ripd.h: Add a new member "ecmp" to "struct rip", indicating whether
ECMP is allowed or not.
Signed-off-by: Feng Lu <lu.feng@6wind.com>
Reviewed-by: Alain Ritoux <alain.ritoux@6wind.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ripd/rip_zebra.c b/ripd/rip_zebra.c
index 8b1c64d..b005ece 100644
--- a/ripd/rip_zebra.c
+++ b/ripd/rip_zebra.c
@@ -92,10 +92,18 @@
(struct prefix_ipv4 *)&rp->p, &api);
if (IS_RIP_DEBUG_ZEBRA)
- zlog_debug ("%s: %s/%d nexthops %d",
- (cmd == ZEBRA_IPV4_ROUTE_ADD) ? \
- "Install into zebra" : "Delete from zebra",
- inet_ntoa (rp->p.u.prefix4), rp->p.prefixlen, count);
+ {
+ if (rip->ecmp)
+ zlog_debug ("%s: %s/%d nexthops %d",
+ (cmd == ZEBRA_IPV4_ROUTE_ADD) ? \
+ "Install into zebra" : "Delete from zebra",
+ inet_ntoa (rp->p.u.prefix4), rp->p.prefixlen, count);
+ else
+ zlog_debug ("%s: %s/%d",
+ (cmd == ZEBRA_IPV4_ROUTE_ADD) ? \
+ "Install into zebra" : "Delete from zebra",
+ inet_ntoa (rp->p.u.prefix4), rp->p.prefixlen);
+ }
rip_global_route_changes++;
}
diff --git a/ripd/ripd.c b/ripd/ripd.c
index b00241c..c69ef7f 100644
--- a/ripd/ripd.c
+++ b/ripd/ripd.c
@@ -155,7 +155,8 @@
static void rip_timeout_update (struct rip_info *rinfo);
/* Add new route to the ECMP list.
- * RETURN: the new entry added in the list
+ * RETURN: the new entry added in the list, or NULL if it is not the first
+ * entry and ECMP is not allowed.
*/
struct rip_info *
rip_ecmp_add (struct rip_info *rinfo_new)
@@ -168,6 +169,11 @@
rp->info = list_new ();
list = (struct list *)rp->info;
+ /* If ECMP is not allowed and some entry already exists in the list,
+ * do nothing. */
+ if (listcount (list) && !rip->ecmp)
+ return NULL;
+
rinfo = rip_info_new ();
memcpy (rinfo, rinfo_new, sizeof (struct rip_info));
listnode_add (list, rinfo);
@@ -3448,6 +3454,80 @@
return CMD_SUCCESS;
}
+/* Update ECMP routes to zebra when ECMP is disabled. */
+static void
+rip_ecmp_disable (void)
+{
+ struct route_node *rp;
+ struct rip_info *rinfo, *tmp_rinfo;
+ struct list *list;
+ struct listnode *node, *nextnode;
+
+ if (!rip)
+ return;
+
+ for (rp = route_top (rip->table); rp; rp = route_next (rp))
+ if ((list = rp->info) != NULL && listcount (list) > 1)
+ {
+ rinfo = listgetdata (listhead (list));
+ if (!rip_route_rte (rinfo))
+ continue;
+
+ /* Drop all other entries, except the first one. */
+ for (ALL_LIST_ELEMENTS (list, node, nextnode, tmp_rinfo))
+ if (tmp_rinfo != rinfo)
+ {
+ RIP_TIMER_OFF (tmp_rinfo->t_timeout);
+ RIP_TIMER_OFF (tmp_rinfo->t_garbage_collect);
+ list_delete_node (list, node);
+ rip_info_free (tmp_rinfo);
+ }
+
+ /* Update zebra. */
+ rip_zebra_ipv4_add (rp);
+
+ /* Set the route change flag. */
+ SET_FLAG (rinfo->flags, RIP_RTF_CHANGED);
+
+ /* Signal the output process to trigger an update. */
+ rip_event (RIP_TRIGGERED_UPDATE, 0);
+ }
+}
+
+DEFUN (rip_allow_ecmp,
+ rip_allow_ecmp_cmd,
+ "allow-ecmp",
+ "Allow Equal Cost MultiPath\n")
+{
+ if (rip->ecmp)
+ {
+ vty_out (vty, "ECMP is already enabled.%s", VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+
+ rip->ecmp = 1;
+ zlog_info ("ECMP is enabled.");
+ return CMD_SUCCESS;
+}
+
+DEFUN (no_rip_allow_ecmp,
+ no_rip_allow_ecmp_cmd,
+ "no allow-ecmp",
+ NO_STR
+ "Allow Equal Cost MultiPath\n")
+{
+ if (!rip->ecmp)
+ {
+ vty_out (vty, "ECMP is already disabled.%s", VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+
+ rip->ecmp = 0;
+ zlog_info ("ECMP is disabled.");
+ rip_ecmp_disable ();
+ return CMD_SUCCESS;
+}
+
/* Print out routes update time. */
static void
rip_vty_out_uptime (struct vty *vty, struct rip_info *rinfo)
@@ -3755,6 +3835,10 @@
rdistance->access_list ? rdistance->access_list : "",
VTY_NEWLINE);
+ /* ECMP configuration. */
+ if (rip->ecmp)
+ vty_out (vty, " allow-ecmp%s", VTY_NEWLINE);
+
/* RIP static route configuration. */
for (rn = route_top (rip->route); rn; rn = route_next (rn))
if (rn->info)
@@ -4092,6 +4176,8 @@
install_element (RIP_NODE, &no_rip_distance_source_cmd);
install_element (RIP_NODE, &rip_distance_source_access_list_cmd);
install_element (RIP_NODE, &no_rip_distance_source_access_list_cmd);
+ install_element (RIP_NODE, &rip_allow_ecmp_cmd);
+ install_element (RIP_NODE, &no_rip_allow_ecmp_cmd);
/* Debug related init. */
rip_debug_init ();
diff --git a/ripd/ripd.h b/ripd/ripd.h
index 0f0e216..4f40e79 100644
--- a/ripd/ripd.h
+++ b/ripd/ripd.h
@@ -143,6 +143,9 @@
u_char distance;
struct route_table *distance_table;
+ /* RIP ECMP flag */
+ unsigned int ecmp;
+
/* For redistribute route map. */
struct
{