[IPV4]: Add default config support after inetdev_init

Previously once inetdev_init has been called on a device any changes
made to ipv4_devconf_dflt would have no effect on that device's
configuration.

This creates a problem since we have moved the point where
inetdev_init is called from when an address is added to where the
device is registered.

This patch is the first half of a set that tries to mimic the old
behaviour while still calling inetdev_init.

It propagates any changes to ipv4_devconf_dflt to those devices that
have not had the corresponding attribute set.

The next patch will forcibly set all values at the point where
inetdev_init was previously called.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 98 insertions, 35 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 00940660739f..e19734795a7b 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1244,6 +1244,91 @@ errout:
 
 #ifdef CONFIG_SYSCTL
 
+static void devinet_copy_dflt_conf(int i)
+{
+        struct net_device *dev;
+
+        read_lock(&dev_base_lock);
+        for_each_netdev(dev) {
+                struct in_device *in_dev;
+                rcu_read_lock();
+                in_dev = __in_dev_get_rcu(dev);
+                if (in_dev && !test_bit(i, in_dev->cnf.state))
+                        in_dev->cnf.data[i] = ipv4_devconf_dflt.data[i];
+                rcu_read_unlock();
+        }
+        read_unlock(&dev_base_lock);
+}
+
+static int devinet_conf_proc(ctl_table *ctl, int write,
+                             struct file* filp, void __user *buffer,
+                             size_t *lenp, loff_t *ppos)
+{
+        int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
+
+        if (write) {
+                struct ipv4_devconf *cnf = ctl->extra1;
+                int i = (int *)ctl->data - cnf->data;
+
+                set_bit(i, cnf->state);
+
+                if (cnf == &ipv4_devconf_dflt)
+                        devinet_copy_dflt_conf(i);
+        }
+
+        return ret;
+}
+
+static int devinet_conf_sysctl(ctl_table *table, int __user *name, int nlen,
+                               void __user *oldval, size_t __user *oldlenp,
+                               void __user *newval, size_t newlen)
+{
+        struct ipv4_devconf *cnf;
+        int *valp = table->data;
+        int new;
+        int i;
+
+        if (!newval || !newlen)
+                return 0;
+
+        if (newlen != sizeof(int))
+                return -EINVAL;
+
+        if (get_user(new, (int __user *)newval))
+                return -EFAULT;
+
+        if (new == *valp)
+                return 0;
+
+        if (oldval && oldlenp) {
+                size_t len;
+
+                if (get_user(len, oldlenp))
+                        return -EFAULT;
+
+                if (len) {
+                        if (len > table->maxlen)
+                                len = table->maxlen;
+                        if (copy_to_user(oldval, valp, len))
+                                return -EFAULT;
+                        if (put_user(len, oldlenp))
+                                return -EFAULT;
+                }
+        }
+
+        *valp = new;
+
+        cnf = table->extra1;
+        i = (int *)table->data - cnf->data;
+
+        set_bit(i, cnf->state);
+
+        if (cnf == &ipv4_devconf_dflt)
+                devinet_copy_dflt_conf(i);
+
+        return 1;
+}
+
 void inet_forward_change(void)
 {
         struct net_device *dev;
@@ -1302,40 +1387,13 @@ int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
                                   void __user *oldval, size_t __user *oldlenp,
                                   void __user *newval, size_t newlen)
 {
-        int *valp = table->data;
-        int new;
-
-        if (!newval || !newlen)
-                return 0;
-
-        if (newlen != sizeof(int))
-                return -EINVAL;
+        int ret = devinet_conf_sysctl(table, name, nlen, oldval, oldlenp,
+                                      newval, newlen);
 
-        if (get_user(new, (int __user *)newval))
-                return -EFAULT;
-
-        if (new == *valp)
-                return 0;
-
-        if (oldval && oldlenp) {
-                size_t len;
-
-                if (get_user(len, oldlenp))
-                        return -EFAULT;
-
-                if (len) {
-                        if (len > table->maxlen)
-                                len = table->maxlen;
-                        if (copy_to_user(oldval, valp, len))
-                                return -EFAULT;
-                        if (put_user(len, oldlenp))
-                                return -EFAULT;
-                }
-        }
+        if (ret == 1)
+                rt_cache_flush(0);
 
-        *valp = new;
-        rt_cache_flush(0);
-        return 1;
+        return ret;
 }
 
 
@@ -1349,13 +1407,16 @@ int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
                 .mode           = mval, \
                 .proc_handler   = proc, \
                 .strategy       = sysctl, \
+                .extra1         = &ipv4_devconf, \
         }
 
 #define DEVINET_SYSCTL_RW_ENTRY(attr, name) \
-        DEVINET_SYSCTL_ENTRY(attr, name, 0644, &proc_dointvec, NULL)
+        DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc, \
+                             devinet_conf_sysctl)
 
 #define DEVINET_SYSCTL_RO_ENTRY(attr, name) \
-        DEVINET_SYSCTL_ENTRY(attr, name, 0444, &proc_dointvec, NULL)
+        DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc, \
+                             devinet_conf_sysctl)
 
 #define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc, sysctl) \
         DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc, sysctl)
@@ -1374,7 +1435,8 @@ static struct devinet_sysctl_table {
 } devinet_sysctl = {
         .devinet_vars = {
                 DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
-                                             devinet_sysctl_forward, NULL),
+                                             devinet_sysctl_forward,
+                                             devinet_conf_sysctl),
                 DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
 
                 DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
@@ -1448,6 +1510,7 @@ static void devinet_sysctl_register(struct in_device *in_dev,
                 return;
         for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
                 t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
+                t->devinet_vars[i].extra1 = p;
         }
 
         if (dev) {