[PATCH 2/2] vlan: Centralize handling of hardware acceleration

[Zhu Yanjun]

2.6.x kernels require a similar logic change as commit 4fba4ca4
[vlan: Centralize handling of hardware acceleration] introduces
for newer kernels.

Since there is something wrong with sending/receiving vlan packets
of tun/tap of kernel 2.6.x. In kernel(3.0+), sending/receiving
vlan packets is centralize handling in kernel. But in kernel 2.6.x,
inserting/extraction vlan tag is still based on nic hardware. Thus,
tun/tap nic driver can not support vlan packets. It is necessary
to centralize handling of hardware acceleration and simulate vlan
rx extraction in tun/tap nic driver to make tun/tap support vlan
packets sending/receiving in kernel 2.6.x.

Signed-off-by: Zhu Yanjun <Yanjun.Zhu@xxxxxxxxxxxxx>
---
 include/linux/if_vlan.h   |    4 +-
 include/linux/netdevice.h |    1 -
 net/8021q/vlan.c          |   47 +++++++++++++++++++
 net/8021q/vlan_core.c     |  110 +++++----------------------------------------
 net/core/dev.c            |   45 +++++++------------
 5 files changed, 74 insertions(+), 133 deletions(-)

diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 7ff9af1..5538dda 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -114,7 +114,7 @@ extern u16 vlan_dev_vlan_id(const struct net_device *dev);
 
 extern int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
 			     u16 vlan_tci, int polling);
-extern int vlan_hwaccel_do_receive(struct sk_buff *skb);
+extern bool vlan_hwaccel_do_receive(struct sk_buff **skb);
 extern int vlan_gro_receive(struct napi_struct *napi, struct vlan_group *grp,
 			    unsigned int vlan_tci, struct sk_buff *skb);
 extern int vlan_gro_frags(struct napi_struct *napi, struct vlan_group *grp,
@@ -140,7 +140,7 @@ static inline int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
 	return NET_XMIT_SUCCESS;
 }
 
-static inline int vlan_hwaccel_do_receive(struct sk_buff *skb)
+static inline bool vlan_hwaccel_do_receive(struct sk_buff **skb)
 {
 	return 0;
 }
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 04c659b..bdb6b82 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1490,7 +1490,6 @@ static inline void napi_free_frags(struct napi_struct *napi)
 	napi->skb = NULL;
 }
 
-extern void		netif_nit_deliver(struct sk_buff *skb);
 extern int		dev_valid_name(const char *name);
 extern int		dev_ioctl(struct net *net, unsigned int cmd, void __user *);
 extern int		dev_ethtool(struct net *net, struct ifreq *);
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index a29c5ab..64c081b 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -92,6 +92,52 @@ struct net_device *__find_vlan_dev(struct net_device *real_dev, u16 vlan_id)
 	return NULL;
 }
 
+bool vlan_hwaccel_do_receive(struct sk_buff **skbp)
+{
+	struct sk_buff *skb = *skbp;
+	u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
+	struct net_device *vlan_dev;
+	struct net_device_stats *stats;
+
+	vlan_dev = __find_vlan_dev(skb->dev, vlan_id);
+	if (!vlan_dev) {
+		if (vlan_id)
+			skb->pkt_type = PACKET_OTHERHOST;
+		return false;
+	}
+
+	skb = *skbp = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return false;
+
+	skb->dev = vlan_dev;
+	skb->priority = vlan_get_ingress_priority(vlan_dev, skb->vlan_tci);
+	skb->vlan_tci = 0;
+
+	stats = &vlan_dev->stats;
+	stats->rx_packets++;
+	stats->rx_bytes += skb->len;
+
+	switch (skb->pkt_type) {
+	case PACKET_BROADCAST:
+		break;
+	case PACKET_MULTICAST:
+		stats->multicast++;
+		break;
+	case PACKET_OTHERHOST:
+		/* Our lower layer thinks this is not local, let's make sure.
+		 * This allows the VLAN to have a different MAC than the
+		 * underlying device, and still route correctly. */
+		if (!compare_ether_addr(eth_hdr(skb)->h_dest,
+					vlan_dev->dev_addr))
+			skb->pkt_type = PACKET_HOST;
+			break;
+	};
+
+	return true;
+}
+extern bool (*__vlan_do_receive)(struct sk_buff **skbp);
+
 static void vlan_group_free(struct vlan_group *grp)
 {
 	int i;
@@ -744,6 +790,7 @@ static int __init vlan_proto_init(void)
 
 	dev_add_pack(&vlan_packet_type);
 	vlan_ioctl_set(vlan_ioctl_handler);
+	__vlan_do_receive = vlan_hwaccel_do_receive;
 	return 0;
 
 err4:
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 7f7de1a..c679535 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -4,64 +4,6 @@
 #include <linux/netpoll.h>
 #include "vlan.h"
 
-/* VLAN rx hw acceleration helper.  This acts like netif_{rx,receive_skb}(). */
-int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
-		      u16 vlan_tci, int polling)
-{
-	if (netpoll_rx(skb))
-		return NET_RX_DROP;
-
-	if (skb_bond_should_drop(skb))
-		goto drop;
-
-	skb->vlan_tci = vlan_tci;
-	skb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);
-
-	if (!skb->dev)
-		goto drop;
-
-	return (polling ? netif_receive_skb(skb) : netif_rx(skb));
-
-drop:
-	dev_kfree_skb_any(skb);
-	return NET_RX_DROP;
-}
-EXPORT_SYMBOL(__vlan_hwaccel_rx);
-
-int vlan_hwaccel_do_receive(struct sk_buff *skb)
-{
-	struct net_device *dev = skb->dev;
-	struct net_device_stats *stats;
-
-	skb->dev = vlan_dev_info(dev)->real_dev;
-	netif_nit_deliver(skb);
-
-	skb->dev = dev;
-	skb->priority = vlan_get_ingress_priority(dev, skb->vlan_tci);
-	skb->vlan_tci = 0;
-
-	stats = &dev->stats;
-	stats->rx_packets++;
-	stats->rx_bytes += skb->len;
-
-	switch (skb->pkt_type) {
-	case PACKET_BROADCAST:
-		break;
-	case PACKET_MULTICAST:
-		stats->multicast++;
-		break;
-	case PACKET_OTHERHOST:
-		/* Our lower layer thinks this is not local, let's make sure.
-		 * This allows the VLAN to have a different MAC than the
-		 * underlying device, and still route correctly. */
-		if (!compare_ether_addr(eth_hdr(skb)->h_dest,
-					dev->dev_addr))
-			skb->pkt_type = PACKET_HOST;
-		break;
-	};
-	return 0;
-}
-
 struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 {
 	return vlan_dev_info(dev)->real_dev;
@@ -74,59 +16,27 @@ u16 vlan_dev_vlan_id(const struct net_device *dev)
 }
 EXPORT_SYMBOL(vlan_dev_vlan_id);
 
-static int vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
-			   unsigned int vlan_tci, struct sk_buff *skb)
+/* VLAN rx hw acceleration helper.  This acts like netif_{rx,receive_skb}(). */
+int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
+			u16 vlan_tci, int polling)
 {
-	struct sk_buff *p;
-
-	if (skb_bond_should_drop(skb))
-		goto drop;
-
-	skb->vlan_tci = vlan_tci;
-	skb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);
-
-	if (!skb->dev)
-		goto drop;
-
-	for (p = napi->gro_list; p; p = p->next) {
-		NAPI_GRO_CB(p)->same_flow =
-			p->dev == skb->dev && !compare_ether_header(
-				skb_mac_header(p), skb_gro_mac_header(skb));
-		NAPI_GRO_CB(p)->flush = 0;
-	}
-
-	return dev_gro_receive(napi, skb);
-
-drop:
-	return GRO_DROP;
+	__vlan_hwaccel_put_tag(skb, vlan_tci);
+	return polling ? netif_receive_skb(skb) : netif_rx(skb); 
 }
+EXPORT_SYMBOL(__vlan_hwaccel_rx);
 
 int vlan_gro_receive(struct napi_struct *napi, struct vlan_group *grp,
 		     unsigned int vlan_tci, struct sk_buff *skb)
 {
-	if (netpoll_rx_on(skb))
-		return vlan_hwaccel_receive_skb(skb, grp, vlan_tci);
-
-	skb_gro_reset_offset(skb);
-
-	return napi_skb_finish(vlan_gro_common(napi, grp, vlan_tci, skb), skb);
+	__vlan_hwaccel_put_tag(skb, vlan_tci);
+	return napi_gro_receive(napi, skb);
 }
 EXPORT_SYMBOL(vlan_gro_receive);
 
 int vlan_gro_frags(struct napi_struct *napi, struct vlan_group *grp,
 		   unsigned int vlan_tci)
 {
-	struct sk_buff *skb = napi_frags_skb(napi);
-
-	if (!skb)
-		return NET_RX_DROP;
-
-	if (netpoll_rx_on(skb)) {
-		skb->protocol = eth_type_trans(skb, skb->dev);
-		return vlan_hwaccel_receive_skb(skb, grp, vlan_tci);
-	}
-
-	return napi_frags_finish(napi, skb,
-				 vlan_gro_common(napi, grp, vlan_tci, skb));
+	__vlan_hwaccel_put_tag(napi->skb, vlan_tci);
+	return napi_gro_frags(napi);
 }
 EXPORT_SYMBOL(vlan_gro_frags);
diff --git a/net/core/dev.c b/net/core/dev.c
index a3802ca..c58520a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2272,33 +2272,8 @@ out:
 }
 #endif
 
-/*
- * 	netif_nit_deliver - deliver received packets to network taps
- * 	@skb: buffer
- *
- * 	This function is used to deliver incoming packets to network
- * 	taps. It should be used when the normal netif_receive_skb path
- * 	is bypassed, for example because of VLAN acceleration.
- */
-void netif_nit_deliver(struct sk_buff *skb)
-{
-	struct packet_type *ptype;
-
-	if (list_empty(&ptype_all))
-		return;
-
-	skb_reset_network_header(skb);
-	skb_reset_transport_header(skb);
-	skb->mac_len = skb->network_header - skb->mac_header;
-
-	rcu_read_lock();
-	list_for_each_entry_rcu(ptype, &ptype_all, list) {
-		if (!ptype->dev || ptype->dev == skb->dev)
-			deliver_skb(skb, ptype, skb->dev);
-	}
-	rcu_read_unlock();
-}
-
+bool (*__vlan_do_receive)(struct sk_buff **skbp) = NULL;
+EXPORT_SYMBOL(__vlan_do_receive);
 /**
  *	netif_receive_skb - process receive buffer from network
  *	@skb: buffer to process
@@ -2325,9 +2300,6 @@ int netif_receive_skb(struct sk_buff *skb)
 	if (!skb->tstamp.tv64)
 		net_timestamp(skb);
 
-	if (skb->vlan_tci && vlan_hwaccel_do_receive(skb))
-		return NET_RX_SUCCESS;
-
 	/* if we've gotten here through NAPI, check netpoll */
 	if (netpoll_receive_skb(skb))
 		return NET_RX_DROP;
@@ -2354,6 +2326,8 @@ int netif_receive_skb(struct sk_buff *skb)
 
 	rcu_read_lock();
 
+another_round:
+
 #ifdef CONFIG_NET_CLS_ACT
 	if (skb->tc_verd & TC_NCLS) {
 		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
@@ -2377,6 +2351,17 @@ int netif_receive_skb(struct sk_buff *skb)
 ncls:
 #endif
 
+	if (vlan_tx_tag_present(skb)) {
+		if (pt_prev) {
+			ret = deliver_skb(skb, pt_prev, orig_dev);
+			pt_prev = NULL;
+		}
+		if (__vlan_do_receive && __vlan_do_receive(&skb)) {
+			goto another_round;
+		} else if (unlikely(!skb))
+			goto out;
+	}
+
 	skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
 	if (!skb)
 		goto out;
-- 
1.7.9.5


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