From 4bf6980dd0328530783fd657c776e3719b421d30 Mon Sep 17 00:00:00 2001 From: Jean-Francois Remy Date: Wed, 14 Jan 2015 04:22:39 +0100 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/core/neighbour.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 8e38f17288d3..8d614c93f86a 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -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 */ -- 2.20.1