dev: always advertise rx_flags changes via netlink

When flags IFF_PROMISC and IFF_ALLMULTI are changed, netlink messages are not
consistent. For example, if a multicast daemon is running (flag IFF_ALLMULTI
set in dev->flags but not dev->gflags, ie not exported to userspace) and then a
user sets it via netlink (flag IFF_ALLMULTI set in dev->flags and dev->gflags, ie
exported to userspace), no netlink message is sent.
Same for IFF_PROMISC and because dev->promiscuity is exported via
IFLA_PROMISCUITY, we may send a netlink message after each change of this
counter.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 23 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 594a6b0ab3da..81340ed7f0f4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4988,7 +4988,7 @@ static void dev_change_rx_flags(struct net_device *dev, int flags)
                 ops->ndo_change_rx_flags(dev, flags);
 }
 
-static int __dev_set_promiscuity(struct net_device *dev, int inc)
+static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify)
 {
         unsigned int old_flags = dev->flags;
         kuid_t uid;
@@ -5031,6 +5031,8 @@ static int __dev_set_promiscuity(struct net_device *dev, int inc)
 
                 dev_change_rx_flags(dev, IFF_PROMISC);
         }
+        if (notify)
+                __dev_notify_flags(dev, old_flags, IFF_PROMISC);
         return 0;
 }
 
@@ -5050,7 +5052,7 @@ int dev_set_promiscuity(struct net_device *dev, int inc)
         unsigned int old_flags = dev->flags;
         int err;
 
-        err = __dev_set_promiscuity(dev, inc);
+        err = __dev_set_promiscuity(dev, inc, true);
         if (err < 0)
                 return err;
         if (dev->flags != old_flags)
@@ -5059,22 +5061,9 @@ int dev_set_promiscuity(struct net_device *dev, int inc)
 }
 EXPORT_SYMBOL(dev_set_promiscuity);
 
-/**
- *      dev_set_allmulti        - update allmulti count on a device
- *      @dev: device
- *      @inc: modifier
- *
- *      Add or remove reception of all multicast frames to a device. While the
- *      count in the device remains above zero the interface remains listening
- *      to all interfaces. Once it hits zero the device reverts back to normal
- *      filtering operation. A negative @inc value is used to drop the counter
- *      when releasing a resource needing all multicasts.
- *      Return 0 if successful or a negative errno code on error.
- */
-
-int dev_set_allmulti(struct net_device *dev, int inc)
+static int __dev_set_allmulti(struct net_device *dev, int inc, bool notify)
 {
-        unsigned int old_flags = dev->flags;
+        unsigned int old_flags = dev->flags, old_gflags = dev->gflags;
 
         ASSERT_RTNL();
 
@@ -5097,9 +5086,30 @@ int dev_set_allmulti(struct net_device *dev, int inc)
         if (dev->flags ^ old_flags) {
                 dev_change_rx_flags(dev, IFF_ALLMULTI);
                 dev_set_rx_mode(dev);
+                if (notify)
+                        __dev_notify_flags(dev, old_flags,
+                                           dev->gflags ^ old_gflags);
         }
         return 0;
 }
+
+/**
+ *      dev_set_allmulti        - update allmulti count on a device
+ *      @dev: device
+ *      @inc: modifier
+ *
+ *      Add or remove reception of all multicast frames to a device. While the
+ *      count in the device remains above zero the interface remains listening
+ *      to all interfaces. Once it hits zero the device reverts back to normal
+ *      filtering operation. A negative @inc value is used to drop the counter
+ *      when releasing a resource needing all multicasts.
+ *      Return 0 if successful or a negative errno code on error.
+ */
+
+int dev_set_allmulti(struct net_device *dev, int inc)
+{
+        return __dev_set_allmulti(dev, inc, true);
+}
 EXPORT_SYMBOL(dev_set_allmulti);
 
 /*
@@ -5124,10 +5134,10 @@ void __dev_set_rx_mode(struct net_device *dev)
                  * therefore calling __dev_set_promiscuity here is safe.
                  */
                 if (!netdev_uc_empty(dev) && !dev->uc_promisc) {
-                        __dev_set_promiscuity(dev, 1);
+                        __dev_set_promiscuity(dev, 1, false);
                         dev->uc_promisc = true;
                 } else if (netdev_uc_empty(dev) && dev->uc_promisc) {
-                        __dev_set_promiscuity(dev, -1);
+                        __dev_set_promiscuity(dev, -1, false);
                         dev->uc_promisc = false;
                 }
         }
@@ -5216,9 +5226,13 @@ int __dev_change_flags(struct net_device *dev, unsigned int flags)
 
         if ((flags ^ dev->gflags) & IFF_PROMISC) {
                 int inc = (flags & IFF_PROMISC) ? 1 : -1;
+                unsigned int old_flags = dev->flags;
 
                 dev->gflags ^= IFF_PROMISC;
-                dev_set_promiscuity(dev, inc);
+
+                if (__dev_set_promiscuity(dev, inc, false) >= 0)
+                        if (dev->flags != old_flags)
+                                dev_set_rx_mode(dev);
         }
 
         /* NOTE: order of synchronization of IFF_PROMISC and IFF_ALLMULTI
@@ -5229,7 +5243,7 @@ int __dev_change_flags(struct net_device *dev, unsigned int flags)
                 int inc = (flags & IFF_ALLMULTI) ? 1 : -1;
 
                 dev->gflags ^= IFF_ALLMULTI;
-                dev_set_allmulti(dev, inc);
+                __dev_set_allmulti(dev, inc, false);
         }
 
         return ret;
@@ -5271,13 +5285,13 @@ void __dev_notify_flags(struct net_device *dev, unsigned int old_flags,
 int dev_change_flags(struct net_device *dev, unsigned int flags)
 {
         int ret;
-        unsigned int changes, old_flags = dev->flags;
+        unsigned int changes, old_flags = dev->flags, old_gflags = dev->gflags;
 
         ret = __dev_change_flags(dev, flags);
         if (ret < 0)
                 return ret;
 
-        changes = old_flags ^ dev->flags;
+        changes = (old_flags ^ dev->flags) | (old_gflags ^ dev->gflags);
         __dev_notify_flags(dev, old_flags, changes);
         return ret;
 }