Subject: v3 [PATCH net-next 5/7] ipv4: Check return of dev_set_allmulti

From: Wang Chen <[email-masked]>
Date: Wed, 02 Jul 2008 16:24:18 +0800

v2->v3
  Do some unwind work when error happen.

allmulti might overflow.
Commit: "netdevice: Fix promiscuity and allmulti overflow" in net-next makes
dev_set_promiscuity/allmulti return error number if overflow happened.

Here, we check the positive increment for allmulti to get error return.

Signed-off-by: Wang Chen <[email-masked]>
---
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 11700a4..b1916d2 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -244,6 +244,13 @@ failure:
 	unregister_netdevice(dev);
 	return NULL;
 }
+
+static void ipmr_unreg_vif(struct net_device *dev)
+{
+	dev_close(dev);
+	unregister_netdevice(dev);
+	free_netdev(dev);
+}
 #endif
 
 /*
@@ -398,6 +405,7 @@ static int vif_add(struct vifctl *vifc, int mrtsock)
 	struct vif_device *v = &vif_table[vifi];
 	struct net_device *dev;
 	struct in_device *in_dev;
+	int err;
 
 	/* Is vif busy ? */
 	if (VIF_EXISTS(vifi))
@@ -415,18 +423,31 @@ static int vif_add(struct vifctl *vifc, int mrtsock)
 		dev = ipmr_reg_vif();
 		if (!dev)
 			return -ENOBUFS;
+		err = dev_set_allmulti(dev, 1);
+		if (err) {
+			ipmr_unreg_vif(dev);
+			return err;
+		}
 		break;
 #endif
 	case VIFF_TUNNEL:
 		dev = ipmr_new_tunnel(vifc);
 		if (!dev)
 			return -ENOBUFS;
+		err = dev_set_allmulti(dev, 1);
+		if (err) {
+			dev_close(dev);
+			return err;
+		}
 		break;
 	case 0:
 		dev = ip_dev_find(&init_net, vifc->vifc_lcl_addr.s_addr);
 		if (!dev)
 			return -EADDRNOTAVAIL;
 		dev_put(dev);
+		err = dev_set_allmulti(dev, 1);
+		if (err)
+			return err;
 		break;
 	default:
 		return -EINVAL;
@@ -435,7 +456,6 @@ static int vif_add(struct vifctl *vifc, int mrtsock)
 	if ((in_dev = __in_dev_get_rtnl(dev)) == NULL)
 		return -EADDRNOTAVAIL;
 	IPV4_DEVCONF(in_dev->cnf, MC_FORWARDING)++;
-	dev_set_allmulti(dev, +1);
 	ip_rt_multicast_event(in_dev);
 
 	/*