nfp: flower vxlan neighbour keep-alive

Periodically receive messages containing the destination IPs of tunnels
that have recently forwarded traffic. Update the neighbour entries 'used'
value for these IPs next hop.

This prevents the neighbour entry from expiring on timeout but rather
signals an ARP to verify the connection. From an NFP perspective, packets
will not fall back mid-flow unless the link is verified to be down.

Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/cmsg.c

@@ -184,6 +184,9 @@ nfp_flower_cmsg_process_one_rx(struct nfp_app *app, struct sk_buff *skb)
 	case NFP_FLOWER_CMSG_TYPE_NO_NEIGH:
 		nfp_tunnel_request_route(app, skb);
 		break;
+	case NFP_FLOWER_CMSG_TYPE_ACTIVE_TUNS:
+		nfp_tunnel_keep_alive(app, skb);
+		break;
 	case NFP_FLOWER_CMSG_TYPE_TUN_NEIGH:
 		/* Acks from the NFP that the route is added - ignore. */
 		break;

drivers/net/ethernet/netronome/nfp/flower/cmsg.h

@@ -319,6 +319,7 @@ enum nfp_flower_cmsg_type_port {
 	NFP_FLOWER_CMSG_TYPE_PORT_MOD =		8,
 	NFP_FLOWER_CMSG_TYPE_NO_NEIGH =		10,
 	NFP_FLOWER_CMSG_TYPE_TUN_MAC =		11,
+	NFP_FLOWER_CMSG_TYPE_ACTIVE_TUNS =	12,
 	NFP_FLOWER_CMSG_TYPE_TUN_NEIGH =	13,
 	NFP_FLOWER_CMSG_TYPE_TUN_IPS =		14,
 	NFP_FLOWER_CMSG_TYPE_FLOW_STATS =	15,

drivers/net/ethernet/netronome/nfp/flower/main.h

@@ -196,5 +196,6 @@ void nfp_tunnel_write_macs(struct nfp_app *app);
 void nfp_tunnel_del_ipv4_off(struct nfp_app *app, __be32 ipv4);
 void nfp_tunnel_add_ipv4_off(struct nfp_app *app, __be32 ipv4);
 void nfp_tunnel_request_route(struct nfp_app *app, struct sk_buff *skb);
+void nfp_tunnel_keep_alive(struct nfp_app *app, struct sk_buff *skb);
 
 #endif

drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c

@@ -36,12 +36,36 @@
 #include <net/netevent.h>
 #include <linux/idr.h>
 #include <net/dst_metadata.h>
+#include <net/arp.h>
 
 #include "cmsg.h"
 #include "main.h"
 #include "../nfp_net_repr.h"
 #include "../nfp_net.h"
 
+#define NFP_FL_MAX_ROUTES               32
+
+/**
+ * struct nfp_tun_active_tuns - periodic message of active tunnels
+ * @seq:		sequence number of the message
+ * @count:		number of tunnels report in message
+ * @flags:		options part of the request
+ * @ipv4:		dest IPv4 address of active route
+ * @egress_port:	port the encapsulated packet egressed
+ * @extra:		reserved for future use
+ * @tun_info:		tunnels that have sent traffic in reported period
+ */
+struct nfp_tun_active_tuns {
+	__be32 seq;
+	__be32 count;
+	__be32 flags;
+	struct route_ip_info {
+		__be32 ipv4;
+		__be32 egress_port;
+		__be32 extra[2];
+	} tun_info[];
+};
+
 /**
  * struct nfp_tun_neigh - neighbour/route entry on the NFP
  * @dst_ipv4:	destination IPv4 address
@@ -147,6 +171,46 @@ struct nfp_tun_mac_non_nfp_idx {
 	struct list_head list;
 };
 
+void nfp_tunnel_keep_alive(struct nfp_app *app, struct sk_buff *skb)
+{
+	struct nfp_tun_active_tuns *payload;
+	struct net_device *netdev;
+	int count, i, pay_len;
+	struct neighbour *n;
+	__be32 ipv4_addr;
+	u32 port;
+
+	payload = nfp_flower_cmsg_get_data(skb);
+	count = be32_to_cpu(payload->count);
+	if (count > NFP_FL_MAX_ROUTES) {
+		nfp_flower_cmsg_warn(app, "Tunnel keep-alive request exceeds max routes.\n");
+		return;
+	}
+
+	pay_len = nfp_flower_cmsg_get_data_len(skb);
+	if (pay_len != sizeof(struct nfp_tun_active_tuns) +
+	    sizeof(struct route_ip_info) * count) {
+		nfp_flower_cmsg_warn(app, "Corruption in tunnel keep-alive message.\n");
+		return;
+	}
+
+	for (i = 0; i < count; i++) {
+		ipv4_addr = payload->tun_info[i].ipv4;
+		port = be32_to_cpu(payload->tun_info[i].egress_port);
+		netdev = nfp_app_repr_get(app, port);
+		if (!netdev)
+			continue;
+
+		n = neigh_lookup(&arp_tbl, &ipv4_addr, netdev);
+		if (!n)
+			continue;
+
+		/* Update the used timestamp of neighbour */
+		neigh_event_send(n, NULL);
+		neigh_release(n);
+	}
+}
+
 static bool nfp_tun_is_netdev_to_offload(struct net_device *netdev)
 {
 	if (!netdev->rtnl_link_ops)