ipvlan: implement VEPA mode

This is very similar to the Macvlan VEPA mode, however, there is some
difference. IPvlan uses the mac-address of the lower device, so the VEPA
mode has implications of ICMP-redirects for packets destined for its
immediate neighbors sharing same master since the packets will have same
source and dest mac. The external switch/router will send redirect msg.

Having said that, this will be useful tool in terms of debugging
since IPvlan will not switch packets within its slaves and rely completely
on the external entity as intended in 802.1Qbg.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 36 insertions, 9 deletions

diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index 9941851..5166575 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -139,6 +139,21 @@ static inline void ipvlan_clear_private(struct ipvl_port *port)
 	port->flags &= ~IPVLAN_F_PRIVATE;
 }
 
+static inline bool ipvlan_is_vepa(const struct ipvl_port *port)
+{
+	return !!(port->flags & IPVLAN_F_VEPA);
+}
+
+static inline void ipvlan_mark_vepa(struct ipvl_port *port)
+{
+	port->flags |= IPVLAN_F_VEPA;
+}
+
+static inline void ipvlan_clear_vepa(struct ipvl_port *port)
+{
+	port->flags &= ~IPVLAN_F_VEPA;
+}
+
 void ipvlan_init_secret(void);
 unsigned int ipvlan_mac_hash(const unsigned char *addr);
 rx_handler_result_t ipvlan_handle_frame(struct sk_buff **pskb);
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 72fd56d..034ae4c 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -514,13 +514,15 @@ static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev)
 	if (!lyr3h)
 		goto out;
 
-	addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
-	if (addr) {
-		if (ipvlan_is_private(ipvlan->port)) {
-			consume_skb(skb);
-			return NET_XMIT_DROP;
+	if (!ipvlan_is_vepa(ipvlan->port)) {
+		addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
+		if (addr) {
+			if (ipvlan_is_private(ipvlan->port)) {
+				consume_skb(skb);
+				return NET_XMIT_DROP;
+			}
+			return ipvlan_rcv_frame(addr, &skb, true);
 		}
-		return ipvlan_rcv_frame(addr, &skb, true);
 	}
 out:
 	ipvlan_skb_crossing_ns(skb, ipvlan->phy_dev);
@@ -535,7 +537,8 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
 	void *lyr3h;
 	int addr_type;
 
-	if (ether_addr_equal(eth->h_dest, eth->h_source)) {
+	if (!ipvlan_is_vepa(ipvlan->port) &&
+	    ether_addr_equal(eth->h_dest, eth->h_source)) {
 		lyr3h = ipvlan_get_L3_hdr(skb, &addr_type);
 		if (lyr3h) {
 			addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 4368afb..a266aa4 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -478,6 +478,11 @@ static int ipvlan_nl_changelink(struct net_device *dev,
 			ipvlan_mark_private(port);
 		else
 			ipvlan_clear_private(port);
+
+		if (flags & IPVLAN_F_VEPA)
+			ipvlan_mark_vepa(port);
+		else
+			ipvlan_clear_vepa(port);
 	}
 
 	return err;
@@ -506,8 +511,12 @@ static int ipvlan_nl_validate(struct nlattr *tb[], struct nlattr *data[],
 	if (data[IFLA_IPVLAN_FLAGS]) {
 		u16 flags = nla_get_u16(data[IFLA_IPVLAN_FLAGS]);
 
-		/* Only one bit is used at this moment. */
-		if (flags & ~IPVLAN_F_PRIVATE)
+		/* Only two bits are used at this moment. */
+		if (flags & ~(IPVLAN_F_PRIVATE | IPVLAN_F_VEPA))
+			return -EINVAL;
+		/* Also both flags can't be active at the same time. */
+		if ((flags & (IPVLAN_F_PRIVATE | IPVLAN_F_VEPA)) ==
+		    (IPVLAN_F_PRIVATE | IPVLAN_F_VEPA))
 			return -EINVAL;
 	}