openwrt/target/linux/generic/patches-4.0/680-NET-skip-GRO-for-foreign-MAC-addresses.patch

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Subject: NET: skip GRO for foreign MAC addresses
For network drivers using napi_gro_receive, packets are run through GRO,
even when the destination MAC address does not match, and they're supposed
to be delivered to another host behind a different bridge port.
This can be very expensive, because for drivers without TSO or scatter-
gather, this can only be undone by copying the skb and checksumming it
again.
To be able to track foreign MAC addresses in an inexpensive way, create
a mask of changed bits in MAC addresses of upper devices. This allows
handling VLANs and bridge devices with different addresses (as long as
they are not too different).
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4005,6 +4005,9 @@ static enum gro_result dev_gro_receive(s
enum gro_result ret;
int grow;
+ if (skb->gro_skip)
+ goto normal;
+
if (!(skb->dev->features & NETIF_F_GRO))
goto normal;
@@ -5152,6 +5155,48 @@ static void __netdev_adjacent_dev_unlink
&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 *private)
@@ -5212,6 +5257,7 @@ static int __netdev_upper_dev_link(struc
goto rollback_lower_mesh;
}
+ netdev_update_addr_mask(dev);
call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
return 0;
@@ -5329,6 +5375,7 @@ void netdev_upper_dev_unlink(struct net_
list_for_each_entry(i, &upper_dev->all_adj_list.upper, list)
__netdev_adjacent_dev_unlink(dev, i->dev);
+ netdev_update_addr_mask(dev);
call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
}
EXPORT_SYMBOL(netdev_upper_dev_unlink);
@@ -5868,6 +5915,7 @@ int dev_set_mac_address(struct net_devic
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;
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1589,6 +1589,8 @@ 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
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -609,7 +609,8 @@ struct sk_buff {
__u8 ipvs_property:1;
__u8 inner_protocol_type:1;
__u8 remcsum_offload:1;
- /* 3 or 5 bit hole */
+ __u8 gro_skip:1;
+ /* 2 or 4 bit hole */
#ifdef CONFIG_NET_SCHED
__u16 tc_index; /* traffic control index */
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -172,6 +172,18 @@ u32 eth_get_headlen(void *data, unsigned
}
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
@@ -199,8 +211,12 @@ __be16 eth_type_trans(struct sk_buff *sk
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