[NETNS][IPV6] ip6_fib - add net to gc timer parameter

The fib tables are now relative to the network namespace. When the
garbage collector timer expires, we must have a network namespace
parameter in order to retrieve the tables. For now this is the
init_net, but we should be able to have a timer per namespace and use
the timer callback parameter to pass the network namespace from the
expired timer.

The timer callback, fib6_run_gc, is actually used to be called
synchronously by some functions and asynchronously when the timer
expires.

When the timer expires, the delay specified for fib6_run_gc parameter
is always zero. So, I changed fib6_run_gc to not be a timer callback
but a function called by the timer callback and I added a timer
callback where its work is just to retrieve from the data arg of the
timer the network namespace and call fib6_run_gc with zero expiring
time and the network namespace parameters. That makes the code cleaner
for the fib6_run_gc callers.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_fib.h

@@ -209,7 +209,8 @@ extern int			fib6_del(struct rt6_info *rt,
 extern void			inet6_rt_notify(int event, struct rt6_info *rt,
 						struct nl_info *info);
 
-extern void			fib6_run_gc(unsigned long dummy);
+extern void			fib6_run_gc(unsigned long expires,
+					    struct net *net);
 
 extern void			fib6_gc_cleanup(void);
 

net/ipv6/ip6_fib.c

@@ -93,7 +93,10 @@ static int fib6_walk_continue(struct fib6_walker_t *w);
 
 static __u32 rt_sernum;
 
-static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0);
+static void fib6_gc_timer_cb(unsigned long arg);
+
+static DEFINE_TIMER(ip6_fib_timer, fib6_gc_timer_cb, 0,
+		    (unsigned long)&init_net);
 
 static struct fib6_walker_t fib6_walker_list = {
 	.prev	= &fib6_walker_list,
@@ -1432,12 +1435,12 @@ static int fib6_age(struct rt6_info *rt, void *arg)
 
 static DEFINE_SPINLOCK(fib6_gc_lock);
 
-void fib6_run_gc(unsigned long dummy)
+void fib6_run_gc(unsigned long expires, struct net *net)
 {
-	if (dummy != ~0UL) {
+	if (expires != ~0UL) {
 		spin_lock_bh(&fib6_gc_lock);
-		gc_args.timeout = dummy ? (int)dummy :
-			init_net.ipv6.sysctl.ip6_rt_gc_interval;
+		gc_args.timeout = expires ? (int)expires :
+			net->ipv6.sysctl.ip6_rt_gc_interval;
 	} else {
 		local_bh_disable();
 		if (!spin_trylock(&fib6_gc_lock)) {
@@ -1445,17 +1448,17 @@ void fib6_run_gc(unsigned long dummy)
 			local_bh_enable();
 			return;
 		}
-		gc_args.timeout = init_net.ipv6.sysctl.ip6_rt_gc_interval;
+		gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
 	}
 	gc_args.more = 0;
 
 	icmp6_dst_gc(&gc_args.more);
 
-	fib6_clean_all(&init_net, fib6_age, 0, NULL);
+	fib6_clean_all(net, fib6_age, 0, NULL);
 
 	if (gc_args.more)
 		mod_timer(&ip6_fib_timer, jiffies +
-			  init_net.ipv6.sysctl.ip6_rt_gc_interval);
+			  net->ipv6.sysctl.ip6_rt_gc_interval);
 	else {
 		del_timer(&ip6_fib_timer);
 		ip6_fib_timer.expires = 0;
@@ -1463,6 +1466,11 @@ void fib6_run_gc(unsigned long dummy)
 	spin_unlock_bh(&fib6_gc_lock);
 }
 
+static void fib6_gc_timer_cb(unsigned long arg)
+{
+	fib6_run_gc(0, (struct net *)arg);
+}
+
 static int fib6_net_init(struct net *net)
 {
 	int ret;

net/ipv6/ndisc.c

@@ -1598,6 +1598,7 @@ int ndisc_rcv(struct sk_buff *skb)
 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
 	struct net_device *dev = ptr;
+	struct net *net = dev->nd_net;
 
 	if (dev->nd_net != &init_net)
 		return NOTIFY_DONE;
@@ -1605,11 +1606,11 @@ static int ndisc_netdev_event(struct notifier_block *this, unsigned long event,
 	switch (event) {
 	case NETDEV_CHANGEADDR:
 		neigh_changeaddr(&nd_tbl, dev);
-		fib6_run_gc(~0UL);
+		fib6_run_gc(~0UL, net);
 		break;
 	case NETDEV_DOWN:
 		neigh_ifdown(&nd_tbl, dev);
-		fib6_run_gc(~0UL);
+		fib6_run_gc(~0UL, net);
 		break;
 	default:
 		break;

net/ipv6/route.c

@@ -40,6 +40,7 @@
 #include <linux/if_arp.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/nsproxy.h>
 #include <net/net_namespace.h>
 #include <net/snmp.h>
 #include <net/ipv6.h>
@@ -995,7 +996,7 @@ static int ip6_dst_gc(struct dst_ops *ops)
 		goto out;
 
 	expire++;
-	fib6_run_gc(expire);
+	fib6_run_gc(expire, &init_net);
 	last_gc = now;
 	if (atomic_read(&ip6_dst_ops.entries) < ip6_dst_ops.gc_thresh)
 		expire = init_net.ipv6.sysctl.ip6_rt_gc_timeout>>1;
@@ -2413,10 +2414,11 @@ static
 int ipv6_sysctl_rtcache_flush(ctl_table *ctl, int write, struct file * filp,
 			      void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-	int delay = init_net.ipv6.sysctl.flush_delay;
+	struct net *net = current->nsproxy->net_ns;
+	int delay = net->ipv6.sysctl.flush_delay;
 	if (write) {
 		proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
-		fib6_run_gc(delay <= 0 ? ~0UL : (unsigned long)delay);
+		fib6_run_gc(delay <= 0 ? ~0UL : (unsigned long)delay, net);
 		return 0;
 	} else
 		return -EINVAL;