neighbour: fix base_reachable_time(_ms) not effective immediatly when changed
When setting base_reachable_time or base_reachable_time_ms on a
specific interface through sysctl or netlink, the reachable_time
value is not updated.
This means that neighbour entries will continue to be updated using the
old value until it is recomputed in neigh_period_work (which
recomputes the value every 300*HZ).
On systems with HZ equal to 1000 for instance, it means 5mins before
the change is effective.
This patch changes this behavior by recomputing reachable_time after
each set on base_reachable_time or base_reachable_time_ms.
The new value will become effective the next time the neighbour's timer
is triggered.
Changes are made in two places: the netlink code for set and the sysctl
handling code. For sysctl, I use a proc_handler. The ipv6 network
code does provide its own handler but it already refreshes
reachable_time correctly so it's not an issue.
Any other user of neighbour which provide its own handlers must
refresh reachable_time.
Signed-off-by: Jean-Francois Remy <jeff@melix.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 8e38f17..8d614c9 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2043,6 +2043,12 @@
case NDTPA_BASE_REACHABLE_TIME:
NEIGH_VAR_SET(p, BASE_REACHABLE_TIME,
nla_get_msecs(tbp[i]));
+ /* update reachable_time as well, otherwise, the change will
+ * only be effective after the next time neigh_periodic_work
+ * decides to recompute it (can be multiple minutes)
+ */
+ p->reachable_time =
+ neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
break;
case NDTPA_GC_STALETIME:
NEIGH_VAR_SET(p, GC_STALETIME,
@@ -2921,6 +2927,31 @@
return ret;
}
+static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos)
+{
+ struct neigh_parms *p = ctl->extra2;
+ int ret;
+
+ if (strcmp(ctl->procname, "base_reachable_time") == 0)
+ ret = neigh_proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
+ else if (strcmp(ctl->procname, "base_reachable_time_ms") == 0)
+ ret = neigh_proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
+ else
+ ret = -1;
+
+ if (write && ret == 0) {
+ /* update reachable_time as well, otherwise, the change will
+ * only be effective after the next time neigh_periodic_work
+ * decides to recompute it
+ */
+ p->reachable_time =
+ neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
+ }
+ return ret;
+}
+
#define NEIGH_PARMS_DATA_OFFSET(index) \
(&((struct neigh_parms *) 0)->data[index])
@@ -3047,6 +3078,19 @@
t->neigh_vars[NEIGH_VAR_RETRANS_TIME_MS].proc_handler = handler;
/* ReachableTime (in milliseconds) */
t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler = handler;
+ } else {
+ /* Those handlers will update p->reachable_time after
+ * base_reachable_time(_ms) is set to ensure the new timer starts being
+ * applied after the next neighbour update instead of waiting for
+ * neigh_periodic_work to update its value (can be multiple minutes)
+ * So any handler that replaces them should do this as well
+ */
+ /* ReachableTime */
+ t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler =
+ neigh_proc_base_reachable_time;
+ /* ReachableTime (in milliseconds) */
+ t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler =
+ neigh_proc_base_reachable_time;
}
/* Don't export sysctls to unprivileged users */
