net: rps: support PPPOE session messages

Inspect the payload of PPPOE session messages for the 4 tuples to generate
skb->rxhash.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -134,6 +134,7 @@
 #include <linux/inetdevice.h>
 #include <linux/cpu_rmap.h>
 #include <linux/if_tunnel.h>
+#include <linux/if_pppox.h>
 
 #include "net-sysfs.h"
 
@@ -2573,6 +2574,13 @@ again:
 		proto = vlan->h_vlan_encapsulated_proto;
 		nhoff += sizeof(*vlan);
 		goto again;
+	case __constant_htons(ETH_P_PPP_SES):
+		if (!pskb_may_pull(skb, PPPOE_SES_HLEN + nhoff))
+			goto done;
+		proto = *((__be16 *) (skb->data + nhoff +
+				      sizeof(struct pppoe_hdr)));
+		nhoff += PPPOE_SES_HLEN;
+		goto again;
 	default:
 		goto done;
 	}