openwrt/target/linux/generic/pending-4.9/680-NET-skip-GRO-for-foreign-MAC-addresses.patch

From: Felix Fietkau <nbd@nbd.name>
Subject: net: replace GRO optimization patch with a new one that supports VLANs/bridges with different MAC addresses

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 include/linux/netdevice.h |  2 ++
 include/linux/skbuff.h    |  3 ++-
 net/core/dev.c            | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 net/ethernet/eth.c        | 18 +++++++++++++++++-
 4 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 780e7171f548..6b738c662bc1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1749,6 +1749,8 @@ struct net_device {
 	struct netdev_hw_addr_list	mc;
 	struct netdev_hw_addr_list	dev_addrs;
 
+	unsigned char		local_addr_mask[MAX_ADDR_LEN];
+
 #ifdef CONFIG_SYSFS
 	struct kset		*queues_kset;
 #endif
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5f3343ae25ef..3a04baab9b28 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -742,7 +742,8 @@ struct sk_buff {
 #ifdef CONFIG_NET_SWITCHDEV
 	__u8			offload_fwd_mark:1;
 #endif
-	/* 2, 4 or 5 bit hole */
+	__u8			gro_skip:1;
+	/* 1, 3 or 4 bit hole */
 
 #ifdef CONFIG_NET_SCHED
 	__u16			tc_index;	/* traffic control index */
diff --git a/net/core/dev.c b/net/core/dev.c
index 2e04fd188081..c7c96308bc84 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4512,6 +4512,9 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 	enum gro_result ret;
 	int grow;
 
+	if (skb->gro_skip)
+		goto normal;
+
 	if (!(skb->dev->features & NETIF_F_GRO))
 		goto normal;
 
@@ -5789,6 +5792,48 @@ static void __netdev_adjacent_dev_unlink_neighbour(struct net_device *dev,
 					   &upper_dev->adj_list.lower);
 }
 
+static void __netdev_addr_mask(unsigned char *mask, const unsigned char *addr,
+			       struct net_device *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->addr_len; i++)
+		mask[i] |= addr[i] ^ dev->dev_addr[i];
+}
+
+static void __netdev_upper_mask(unsigned char *mask, struct net_device *dev,
+				struct net_device *lower)
+{
+	struct net_device *cur;
+	struct list_head *iter;
+
+	netdev_for_each_upper_dev_rcu(dev, cur, iter) {
+		__netdev_addr_mask(mask, cur->dev_addr, lower);
+		__netdev_upper_mask(mask, cur, lower);
+	}
+}
+
+static void __netdev_update_addr_mask(struct net_device *dev)
+{
+	unsigned char mask[MAX_ADDR_LEN];
+	struct net_device *cur;
+	struct list_head *iter;
+
+	memset(mask, 0, sizeof(mask));
+	__netdev_upper_mask(mask, dev, dev);
+	memcpy(dev->local_addr_mask, mask, dev->addr_len);
+
+	netdev_for_each_lower_dev(dev, cur, iter)
+		__netdev_update_addr_mask(cur);
+}
+
+static void netdev_update_addr_mask(struct net_device *dev)
+{
+	rcu_read_lock();
+	__netdev_update_addr_mask(dev);
+	rcu_read_unlock();
+}
+
 static int __netdev_upper_dev_link(struct net_device *dev,
 				   struct net_device *upper_dev, bool master,
 				   void *upper_priv, void *upper_info)
@@ -5987,6 +6032,8 @@ void netdev_upper_dev_unlink(struct net_device *dev,
 	list_for_each_entry(i, &upper_dev->all_adj_list.upper, list)
 		__netdev_adjacent_dev_unlink(dev, i->dev, i->ref_nr);
 
+	netdev_update_addr_mask(dev);
+	netdev_update_addr_mask(dev);
 	call_netdevice_notifiers_info(NETDEV_CHANGEUPPER, dev,
 				      &changeupper_info.info);
 }
@@ -6587,6 +6634,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
 	if (err)
 		return err;
 	dev->addr_assign_type = NET_ADDR_SET;
+	netdev_update_addr_mask(dev);
 	call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 	add_device_randomness(dev->dev_addr, dev->addr_len);
 	return 0;
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index fbf1de965a9a..6a6d90b9a880 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -143,6 +143,18 @@ u32 eth_get_headlen(void *data, unsigned int len)
 }
 EXPORT_SYMBOL(eth_get_headlen);
 
+static inline bool
+eth_check_local_mask(const void *addr1, const void *addr2, const void *mask)
+{
+	const u16 *a1 = addr1;
+	const u16 *a2 = addr2;
+	const u16 *m = mask;
+
+	return (((a1[0] ^ a2[0]) & ~m[0]) |
+		((a1[1] ^ a2[1]) & ~m[1]) |
+		((a1[2] ^ a2[2]) & ~m[2]));
+}
+
 /**
  * eth_type_trans - determine the packet's protocol ID.
  * @skb: received socket data
@@ -171,8 +183,12 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
 			skb->pkt_type = PACKET_MULTICAST;
 	}
 	else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
-						   dev->dev_addr)))
+						   dev->dev_addr))) {
 		skb->pkt_type = PACKET_OTHERHOST;
+		if (eth_check_local_mask(eth->h_dest, dev->dev_addr,
+					 dev->local_addr_mask))
+			skb->gro_skip = 1;
+	}
 
 	/*
 	 * Some variants of DSA tagging don't have an ethertype field
-- 
2.11.0