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neighbour: fix base_reachable_time(_ms) not effective immediatly when changed

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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>
This commit is contained in:
Jean-Francois Remy 2015-01-14 04:22:39 +01:00 committed by David S. Miller
parent 3d125f9c91
commit 4bf6980dd0
1 changed files with 44 additions and 0 deletions
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44
net/core/neighbour.c
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@ -2043,6 +2043,12 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
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 @@ static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
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 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
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 */