sysctl: fix neighbour table sysctls.

- In ipv6 ndisc_ifinfo_syctl_change so it doesn't depend on binary
  sysctl names for a function that works with proc.

- In neighbour.c reorder the table to put the possibly unused entries
  at the end so we can remove them by terminating the table early.

- In neighbour.c kill the entries with questionable binary sysctl
  handling behavior.

- In neighbour.c if we don't have a strategy routine remove the
  binary path.  So we don't the default sysctl strategy routine
  on data that is not ready for it.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/core/neighbour.c

@@ -2496,7 +2496,6 @@ static struct neigh_sysctl_table {
 			.proc_handler	= &proc_dointvec,
 		},
 		{
-			.ctl_name	= NET_NEIGH_RETRANS_TIME,
 			.procname	= "retrans_time",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
@@ -2541,26 +2540,39 @@ static struct neigh_sysctl_table {
 			.proc_handler	= &proc_dointvec,
 		},
 		{
-			.ctl_name	= NET_NEIGH_ANYCAST_DELAY,
 			.procname	= "anycast_delay",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
 			.proc_handler	= &proc_dointvec_userhz_jiffies,
 		},
 		{
-			.ctl_name	= NET_NEIGH_PROXY_DELAY,
 			.procname	= "proxy_delay",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
 			.proc_handler	= &proc_dointvec_userhz_jiffies,
 		},
 		{
-			.ctl_name	= NET_NEIGH_LOCKTIME,
 			.procname	= "locktime",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
 			.proc_handler	= &proc_dointvec_userhz_jiffies,
 		},
+		{
+			.ctl_name	= NET_NEIGH_RETRANS_TIME_MS,
+			.procname	= "retrans_time_ms",
+			.maxlen		= sizeof(int),
+			.mode		= 0644,
+			.proc_handler	= &proc_dointvec_ms_jiffies,
+			.strategy	= &sysctl_ms_jiffies,
+		},
+		{
+			.ctl_name	= NET_NEIGH_REACHABLE_TIME_MS,
+			.procname	= "base_reachable_time_ms",
+			.maxlen		= sizeof(int),
+			.mode		= 0644,
+			.proc_handler	= &proc_dointvec_ms_jiffies,
+			.strategy	= &sysctl_ms_jiffies,
+		},
 		{
 			.ctl_name	= NET_NEIGH_GC_INTERVAL,
 			.procname	= "gc_interval",
@@ -2590,22 +2602,7 @@ static struct neigh_sysctl_table {
 			.mode		= 0644,
 			.proc_handler	= &proc_dointvec,
 		},
-		{
-			.ctl_name	= NET_NEIGH_RETRANS_TIME_MS,
-			.procname	= "retrans_time_ms",
-			.maxlen		= sizeof(int),
-			.mode		= 0644,
-			.proc_handler	= &proc_dointvec_ms_jiffies,
-			.strategy	= &sysctl_ms_jiffies,
-		},
-		{
-			.ctl_name	= NET_NEIGH_REACHABLE_TIME_MS,
-			.procname	= "base_reachable_time_ms",
-			.maxlen		= sizeof(int),
-			.mode		= 0644,
-			.proc_handler	= &proc_dointvec_ms_jiffies,
-			.strategy	= &sysctl_ms_jiffies,
-		},
+		{}
 	},
 	.neigh_dev = {
 		{
@@ -2658,42 +2655,48 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
 	t->neigh_vars[9].data  = &p->anycast_delay;
 	t->neigh_vars[10].data = &p->proxy_delay;
 	t->neigh_vars[11].data = &p->locktime;
+	t->neigh_vars[12].data  = &p->retrans_time;
+	t->neigh_vars[13].data  = &p->base_reachable_time;
 
 	if (dev) {
 		dev_name_source = dev->name;
 		t->neigh_dev[0].ctl_name = dev->ifindex;
-		t->neigh_vars[12].procname = NULL;
-		t->neigh_vars[13].procname = NULL;
-		t->neigh_vars[14].procname = NULL;
-		t->neigh_vars[15].procname = NULL;
+		/* Terminate the table early */
+		memset(&t->neigh_vars[14], 0, sizeof(t->neigh_vars[14]));
 	} else {
 		dev_name_source = t->neigh_dev[0].procname;
-		t->neigh_vars[12].data = (int *)(p + 1);
-		t->neigh_vars[13].data = (int *)(p + 1) + 1;
-		t->neigh_vars[14].data = (int *)(p + 1) + 2;
-		t->neigh_vars[15].data = (int *)(p + 1) + 3;
+		t->neigh_vars[14].data = (int *)(p + 1);
+		t->neigh_vars[15].data = (int *)(p + 1) + 1;
+		t->neigh_vars[16].data = (int *)(p + 1) + 2;
+		t->neigh_vars[17].data = (int *)(p + 1) + 3;
 	}
 
-	t->neigh_vars[16].data  = &p->retrans_time;
-	t->neigh_vars[17].data  = &p->base_reachable_time;
 
 	if (handler || strategy) {
 		/* RetransTime */
 		t->neigh_vars[3].proc_handler = handler;
 		t->neigh_vars[3].strategy = strategy;
 		t->neigh_vars[3].extra1 = dev;
+		if (!strategy)
+			t->neigh_vars[3].ctl_name = CTL_UNNUMBERED;
 		/* ReachableTime */
 		t->neigh_vars[4].proc_handler = handler;
 		t->neigh_vars[4].strategy = strategy;
 		t->neigh_vars[4].extra1 = dev;
+		if (!strategy)
+			t->neigh_vars[4].ctl_name = CTL_UNNUMBERED;
 		/* RetransTime (in milliseconds)*/
-		t->neigh_vars[16].proc_handler = handler;
-		t->neigh_vars[16].strategy = strategy;
-		t->neigh_vars[16].extra1 = dev;
+		t->neigh_vars[12].proc_handler = handler;
+		t->neigh_vars[12].strategy = strategy;
+		t->neigh_vars[12].extra1 = dev;
+		if (!strategy)
+			t->neigh_vars[12].ctl_name = CTL_UNNUMBERED;
 		/* ReachableTime (in milliseconds) */
-		t->neigh_vars[17].proc_handler = handler;
-		t->neigh_vars[17].strategy = strategy;
-		t->neigh_vars[17].extra1 = dev;
+		t->neigh_vars[13].proc_handler = handler;
+		t->neigh_vars[13].strategy = strategy;
+		t->neigh_vars[13].extra1 = dev;
+		if (!strategy)
+			t->neigh_vars[13].ctl_name = CTL_UNNUMBERED;
 	}
 
 	dev_name = kstrdup(dev_name_source, GFP_KERNEL);

net/ipv6/ndisc.c

@@ -1658,30 +1658,26 @@ int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, struct file * f
 	struct inet6_dev *idev;
 	int ret;
 
-	if (ctl->ctl_name == NET_NEIGH_RETRANS_TIME ||
-	    ctl->ctl_name == NET_NEIGH_REACHABLE_TIME)
+	if ((strcmp(ctl->procname, "retrans_time") == 0) ||
+	    (strcmp(ctl->procname, "base_reachable_time") == 0))
 		ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
 
-	switch (ctl->ctl_name) {
-	case NET_NEIGH_RETRANS_TIME:
+	if (strcmp(ctl->procname, "retrans_time") == 0)
 		ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
-		break;
-	case NET_NEIGH_REACHABLE_TIME:
+
+	else if (strcmp(ctl->procname, "base_reachable_time") == 0)
 		ret = proc_dointvec_jiffies(ctl, write,
 					    filp, buffer, lenp, ppos);
-		break;
-	case NET_NEIGH_RETRANS_TIME_MS:
-	case NET_NEIGH_REACHABLE_TIME_MS:
+
+	else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
+		 (strcmp(ctl->procname, "base_reacable_time_ms") == 0))
 		ret = proc_dointvec_ms_jiffies(ctl, write,
 					       filp, buffer, lenp, ppos);
-		break;
-	default:
+	else
 		ret = -1;
-	}
 
 	if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
-		if (ctl->ctl_name == NET_NEIGH_REACHABLE_TIME ||
-		    ctl->ctl_name == NET_NEIGH_REACHABLE_TIME_MS)
+		if (ctl->data == &idev->nd_parms->base_reachable_time)
 			idev->nd_parms->reachable_time = neigh_rand_reach_time(idev->nd_parms->base_reachable_time);
 		idev->tstamp = jiffies;
 		inet6_ifinfo_notify(RTM_NEWLINK, idev);