net/sched: flower: Add L2TPv3 filter

Add support for matching on L2TPv3 session ID.
Session ID can be specified only when ip proto was
set to IPPROTO_L2TP.

Example filter:
  # tc filter add dev $PF1 ingress prio 1 protocol ip \
      flower \
        ip_proto l2tp \
        l2tpv3_sid 1234 \
        skip_sw \
      action mirred egress redirect dev $VF1_PR
Acked-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/uapi/linux/pkt_cls.h

@@ -592,6 +592,8 @@ enum {
 	TCA_FLOWER_KEY_PPPOE_SID,	/* be16 */
 	TCA_FLOWER_KEY_PPP_PROTO,	/* be16 */
 
+	TCA_FLOWER_KEY_L2TPV3_SID,	/* be32 */
+
 	__TCA_FLOWER_MAX,
 };
 

net/sched/cls_flower.c

@@ -69,6 +69,7 @@ struct fl_flow_key {
 	struct flow_dissector_key_hash hash;
 	struct flow_dissector_key_num_of_vlans num_of_vlans;
 	struct flow_dissector_key_pppoe pppoe;
+	struct flow_dissector_key_l2tpv3 l2tpv3;
 } __aligned(BITS_PER_LONG / 8); /* Ensure that we can do comparisons as longs. */
 
 struct fl_flow_mask_range {
@@ -712,6 +713,7 @@ static const struct nla_policy fl_policy[TCA_FLOWER_MAX + 1] = {
 	[TCA_FLOWER_KEY_NUM_OF_VLANS]	= { .type = NLA_U8 },
 	[TCA_FLOWER_KEY_PPPOE_SID]	= { .type = NLA_U16 },
 	[TCA_FLOWER_KEY_PPP_PROTO]	= { .type = NLA_U16 },
+	[TCA_FLOWER_KEY_L2TPV3_SID]	= { .type = NLA_U32 },
 
 };
 
@@ -1790,6 +1792,11 @@ static int fl_set_key(struct net *net, struct nlattr **tb,
 		fl_set_key_val(tb, key->arp.tha, TCA_FLOWER_KEY_ARP_THA,
 			       mask->arp.tha, TCA_FLOWER_KEY_ARP_THA_MASK,
 			       sizeof(key->arp.tha));
+	} else if (key->basic.ip_proto == IPPROTO_L2TP) {
+		fl_set_key_val(tb, &key->l2tpv3.session_id,
+			       TCA_FLOWER_KEY_L2TPV3_SID,
+			       &mask->l2tpv3.session_id, TCA_FLOWER_UNSPEC,
+			       sizeof(key->l2tpv3.session_id));
 	}
 
 	if (key->basic.ip_proto == IPPROTO_TCP ||
@@ -1970,6 +1977,8 @@ static void fl_init_dissector(struct flow_dissector *dissector,
 			     FLOW_DISSECTOR_KEY_NUM_OF_VLANS, num_of_vlans);
 	FL_KEY_SET_IF_MASKED(mask, keys, cnt,
 			     FLOW_DISSECTOR_KEY_PPPOE, pppoe);
+	FL_KEY_SET_IF_MASKED(mask, keys, cnt,
+			     FLOW_DISSECTOR_KEY_L2TPV3, l2tpv3);
 
 	skb_flow_dissector_init(dissector, keys, cnt);
 }
@@ -3196,6 +3205,13 @@ static int fl_dump_key(struct sk_buff *skb, struct net *net,
 				  mask->arp.tha, TCA_FLOWER_KEY_ARP_THA_MASK,
 				  sizeof(key->arp.tha))))
 		goto nla_put_failure;
+	else if (key->basic.ip_proto == IPPROTO_L2TP &&
+		 fl_dump_key_val(skb, &key->l2tpv3.session_id,
+				 TCA_FLOWER_KEY_L2TPV3_SID,
+				 &mask->l2tpv3.session_id,
+				 TCA_FLOWER_UNSPEC,
+				 sizeof(key->l2tpv3.session_id)))
+		goto nla_put_failure;
 
 	if ((key->basic.ip_proto == IPPROTO_TCP ||
 	     key->basic.ip_proto == IPPROTO_UDP ||