nfp: flower vxlan neighbour offload

Receive a request when the NFP does not know the next hop for a packet
that is to be encapsulated in a VXLAN tunnel. Do a route lookup, determine
the next hop entry and update neighbour table on NFP. Monitor the kernel
neighbour table for link changes and update NFP with relevant information.
Overwrite routes with zero values on the NFP when they expire.

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

@@ -181,6 +181,12 @@ nfp_flower_cmsg_process_one_rx(struct nfp_app *app, struct sk_buff *skb)
 	case NFP_FLOWER_CMSG_TYPE_FLOW_STATS:
 		nfp_flower_rx_flow_stats(app, skb);
 		break;
+	case NFP_FLOWER_CMSG_TYPE_NO_NEIGH:
+		nfp_tunnel_request_route(app, skb);
+		break;
+	case NFP_FLOWER_CMSG_TYPE_TUN_NEIGH:
+		/* Acks from the NFP that the route is added - ignore. */
+		break;
 	default:
 		nfp_flower_cmsg_warn(app, "Cannot handle invalid repr control type %u\n",
 				     type);

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

@@ -317,7 +317,9 @@ enum nfp_flower_cmsg_type_port {
 	NFP_FLOWER_CMSG_TYPE_FLOW_DEL =		2,
 	NFP_FLOWER_CMSG_TYPE_MAC_REPR =		7,
 	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_TUN_NEIGH =	13,
 	NFP_FLOWER_CMSG_TYPE_TUN_IPS =		14,
 	NFP_FLOWER_CMSG_TYPE_FLOW_STATS =	15,
 	NFP_FLOWER_CMSG_TYPE_PORT_ECHO =	16,

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

@@ -87,12 +87,15 @@ struct nfp_fl_stats_id {
  * @nfp_mac_off_list:	List of MAC addresses to offload
  * @nfp_mac_index_list:	List of unique 8-bit indexes for non NFP netdevs
  * @nfp_ipv4_off_list:	List of IPv4 addresses to offload
+ * @nfp_neigh_off_list:	List of neighbour offloads
  * @nfp_mac_off_lock:	Lock for the MAC address list
  * @nfp_mac_index_lock:	Lock for the MAC index list
  * @nfp_ipv4_off_lock:	Lock for the IPv4 address list
+ * @nfp_neigh_off_lock:	Lock for the neighbour address list
  * @nfp_mac_off_ids:	IDA to manage id assignment for offloaded macs
  * @nfp_mac_off_count:	Number of MACs in address list
  * @nfp_tun_mac_nb:	Notifier to monitor link state
+ * @nfp_tun_neigh_nb:	Notifier to monitor neighbour state
  */
 struct nfp_flower_priv {
 	struct nfp_app *app;
@@ -108,12 +111,15 @@ struct nfp_flower_priv {
 	struct list_head nfp_mac_off_list;
 	struct list_head nfp_mac_index_list;
 	struct list_head nfp_ipv4_off_list;
+	struct list_head nfp_neigh_off_list;
 	struct mutex nfp_mac_off_lock;
 	struct mutex nfp_mac_index_lock;
 	struct mutex nfp_ipv4_off_lock;
+	struct mutex nfp_neigh_off_lock;
 	struct ida nfp_mac_off_ids;
 	int nfp_mac_off_count;
 	struct notifier_block nfp_tun_mac_nb;
+	struct notifier_block nfp_tun_neigh_nb;
 };
 
 struct nfp_fl_key_ls {
@@ -189,5 +195,6 @@ void nfp_tunnel_config_stop(struct nfp_app *app);
 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);
 
 #endif

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

@@ -33,6 +33,7 @@
 
 #include <linux/etherdevice.h>
 #include <linux/inetdevice.h>
+#include <net/netevent.h>
 #include <linux/idr.h>
 #include <net/dst_metadata.h>
 
@@ -41,6 +42,44 @@
 #include "../nfp_net_repr.h"
 #include "../nfp_net.h"
 
+/**
+ * struct nfp_tun_neigh - neighbour/route entry on the NFP
+ * @dst_ipv4:	destination IPv4 address
+ * @src_ipv4:	source IPv4 address
+ * @dst_addr:	destination MAC address
+ * @src_addr:	source MAC address
+ * @port_id:	NFP port to output packet on - associated with source IPv4
+ */
+struct nfp_tun_neigh {
+	__be32 dst_ipv4;
+	__be32 src_ipv4;
+	u8 dst_addr[ETH_ALEN];
+	u8 src_addr[ETH_ALEN];
+	__be32 port_id;
+};
+
+/**
+ * struct nfp_tun_req_route_ipv4 - NFP requests a route/neighbour lookup
+ * @ingress_port:	ingress port of packet that signalled request
+ * @ipv4_addr:		destination ipv4 address for route
+ * @reserved:		reserved for future use
+ */
+struct nfp_tun_req_route_ipv4 {
+	__be32 ingress_port;
+	__be32 ipv4_addr;
+	__be32 reserved[2];
+};
+
+/**
+ * struct nfp_ipv4_route_entry - routes that are offloaded to the NFP
+ * @ipv4_addr:	destination of route
+ * @list:	list pointer
+ */
+struct nfp_ipv4_route_entry {
+	__be32 ipv4_addr;
+	struct list_head list;
+};
+
 #define NFP_FL_IPV4_ADDRS_MAX        32
 
 /**
@@ -137,6 +176,197 @@ nfp_flower_xmit_tun_conf(struct nfp_app *app, u8 mtype, u16 plen, void *pdata)
 	return 0;
 }
 
+static bool nfp_tun_has_route(struct nfp_app *app, __be32 ipv4_addr)
+{
+	struct nfp_flower_priv *priv = app->priv;
+	struct nfp_ipv4_route_entry *entry;
+	struct list_head *ptr, *storage;
+
+	mutex_lock(&priv->nfp_neigh_off_lock);
+	list_for_each_safe(ptr, storage, &priv->nfp_neigh_off_list) {
+		entry = list_entry(ptr, struct nfp_ipv4_route_entry, list);
+		if (entry->ipv4_addr == ipv4_addr) {
+			mutex_unlock(&priv->nfp_neigh_off_lock);
+			return true;
+		}
+	}
+	mutex_unlock(&priv->nfp_neigh_off_lock);
+	return false;
+}
+
+static void nfp_tun_add_route_to_cache(struct nfp_app *app, __be32 ipv4_addr)
+{
+	struct nfp_flower_priv *priv = app->priv;
+	struct nfp_ipv4_route_entry *entry;
+	struct list_head *ptr, *storage;
+
+	mutex_lock(&priv->nfp_neigh_off_lock);
+	list_for_each_safe(ptr, storage, &priv->nfp_neigh_off_list) {
+		entry = list_entry(ptr, struct nfp_ipv4_route_entry, list);
+		if (entry->ipv4_addr == ipv4_addr) {
+			mutex_unlock(&priv->nfp_neigh_off_lock);
+			return;
+		}
+	}
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry) {
+		mutex_unlock(&priv->nfp_neigh_off_lock);
+		nfp_flower_cmsg_warn(app, "Mem error when storing new route.\n");
+		return;
+	}
+
+	entry->ipv4_addr = ipv4_addr;
+	list_add_tail(&entry->list, &priv->nfp_neigh_off_list);
+	mutex_unlock(&priv->nfp_neigh_off_lock);
+}
+
+static void nfp_tun_del_route_from_cache(struct nfp_app *app, __be32 ipv4_addr)
+{
+	struct nfp_flower_priv *priv = app->priv;
+	struct nfp_ipv4_route_entry *entry;
+	struct list_head *ptr, *storage;
+
+	mutex_lock(&priv->nfp_neigh_off_lock);
+	list_for_each_safe(ptr, storage, &priv->nfp_neigh_off_list) {
+		entry = list_entry(ptr, struct nfp_ipv4_route_entry, list);
+		if (entry->ipv4_addr == ipv4_addr) {
+			list_del(&entry->list);
+			kfree(entry);
+			break;
+		}
+	}
+	mutex_unlock(&priv->nfp_neigh_off_lock);
+}
+
+static void
+nfp_tun_write_neigh(struct net_device *netdev, struct nfp_app *app,
+		    struct flowi4 *flow, struct neighbour *neigh)
+{
+	struct nfp_tun_neigh payload;
+
+	/* Only offload representor IPv4s for now. */
+	if (!nfp_netdev_is_nfp_repr(netdev))
+		return;
+
+	memset(&payload, 0, sizeof(struct nfp_tun_neigh));
+	payload.dst_ipv4 = flow->daddr;
+
+	/* If entry has expired send dst IP with all other fields 0. */
+	if (!(neigh->nud_state & NUD_VALID)) {
+		nfp_tun_del_route_from_cache(app, payload.dst_ipv4);
+		/* Trigger ARP to verify invalid neighbour state. */
+		neigh_event_send(neigh, NULL);
+		goto send_msg;
+	}
+
+	/* Have a valid neighbour so populate rest of entry. */
+	payload.src_ipv4 = flow->saddr;
+	ether_addr_copy(payload.src_addr, netdev->dev_addr);
+	neigh_ha_snapshot(payload.dst_addr, neigh, netdev);
+	payload.port_id = cpu_to_be32(nfp_repr_get_port_id(netdev));
+	/* Add destination of new route to NFP cache. */
+	nfp_tun_add_route_to_cache(app, payload.dst_ipv4);
+
+send_msg:
+	nfp_flower_xmit_tun_conf(app, NFP_FLOWER_CMSG_TYPE_TUN_NEIGH,
+				 sizeof(struct nfp_tun_neigh),
+				 (unsigned char *)&payload);
+}
+
+static int
+nfp_tun_neigh_event_handler(struct notifier_block *nb, unsigned long event,
+			    void *ptr)
+{
+	struct nfp_flower_priv *app_priv;
+	struct netevent_redirect *redir;
+	struct flowi4 flow = {};
+	struct neighbour *n;
+	struct nfp_app *app;
+	struct rtable *rt;
+	int err;
+
+	switch (event) {
+	case NETEVENT_REDIRECT:
+		redir = (struct netevent_redirect *)ptr;
+		n = redir->neigh;
+		break;
+	case NETEVENT_NEIGH_UPDATE:
+		n = (struct neighbour *)ptr;
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	flow.daddr = *(__be32 *)n->primary_key;
+
+	/* Only concerned with route changes for representors. */
+	if (!nfp_netdev_is_nfp_repr(n->dev))
+		return NOTIFY_DONE;
+
+	app_priv = container_of(nb, struct nfp_flower_priv, nfp_tun_neigh_nb);
+	app = app_priv->app;
+
+	/* Only concerned with changes to routes already added to NFP. */
+	if (!nfp_tun_has_route(app, flow.daddr))
+		return NOTIFY_DONE;
+
+#if IS_ENABLED(CONFIG_INET)
+	/* Do a route lookup to populate flow data. */
+	rt = ip_route_output_key(dev_net(n->dev), &flow);
+	err = PTR_ERR_OR_ZERO(rt);
+	if (err)
+		return NOTIFY_DONE;
+#else
+	return NOTIFY_DONE;
+#endif
+
+	flow.flowi4_proto = IPPROTO_UDP;
+	nfp_tun_write_neigh(n->dev, app, &flow, n);
+
+	return NOTIFY_OK;
+}
+
+void nfp_tunnel_request_route(struct nfp_app *app, struct sk_buff *skb)
+{
+	struct nfp_tun_req_route_ipv4 *payload;
+	struct net_device *netdev;
+	struct flowi4 flow = {};
+	struct neighbour *n;
+	struct rtable *rt;
+	int err;
+
+	payload = nfp_flower_cmsg_get_data(skb);
+
+	netdev = nfp_app_repr_get(app, be32_to_cpu(payload->ingress_port));
+	if (!netdev)
+		goto route_fail_warning;
+
+	flow.daddr = payload->ipv4_addr;
+	flow.flowi4_proto = IPPROTO_UDP;
+
+#if IS_ENABLED(CONFIG_INET)
+	/* Do a route lookup on same namespace as ingress port. */
+	rt = ip_route_output_key(dev_net(netdev), &flow);
+	err = PTR_ERR_OR_ZERO(rt);
+	if (err)
+		goto route_fail_warning;
+#else
+	goto route_fail_warning;
+#endif
+
+	/* Get the neighbour entry for the lookup */
+	n = dst_neigh_lookup(&rt->dst, &flow.daddr);
+	ip_rt_put(rt);
+	if (!n)
+		goto route_fail_warning;
+	nfp_tun_write_neigh(n->dev, app, &flow, n);
+	neigh_release(n);
+	return;
+
+route_fail_warning:
+	nfp_flower_cmsg_warn(app, "Requested route not found.\n");
+}
+
 static void nfp_tun_write_ipv4_list(struct nfp_app *app)
 {
 	struct nfp_flower_priv *priv = app->priv;
@@ -434,10 +664,19 @@ int nfp_tunnel_config_start(struct nfp_app *app)
 	mutex_init(&priv->nfp_ipv4_off_lock);
 	INIT_LIST_HEAD(&priv->nfp_ipv4_off_list);
 
+	/* Initialise priv data for neighbour offloading. */
+	mutex_init(&priv->nfp_neigh_off_lock);
+	INIT_LIST_HEAD(&priv->nfp_neigh_off_list);
+	priv->nfp_tun_neigh_nb.notifier_call = nfp_tun_neigh_event_handler;
+
 	err = register_netdevice_notifier(&priv->nfp_tun_mac_nb);
 	if (err)
 		goto err_free_mac_ida;
 
+	err = register_netevent_notifier(&priv->nfp_tun_neigh_nb);
+	if (err)
+		goto err_unreg_mac_nb;
+
 	/* Parse netdevs already registered for MACs that need offloaded. */
 	rtnl_lock();
 	for_each_netdev(&init_net, netdev)
@@ -446,6 +685,8 @@ int nfp_tunnel_config_start(struct nfp_app *app)
 
 	return 0;
 
+err_unreg_mac_nb:
+	unregister_netdevice_notifier(&priv->nfp_tun_mac_nb);
 err_free_mac_ida:
 	ida_destroy(&priv->nfp_mac_off_ids);
 	return err;
@@ -455,11 +696,13 @@ void nfp_tunnel_config_stop(struct nfp_app *app)
 {
 	struct nfp_tun_mac_offload_entry *mac_entry;
 	struct nfp_flower_priv *priv = app->priv;
+	struct nfp_ipv4_route_entry *route_entry;
 	struct nfp_tun_mac_non_nfp_idx *mac_idx;
 	struct nfp_ipv4_addr_entry *ip_entry;
 	struct list_head *ptr, *storage;
 
 	unregister_netdevice_notifier(&priv->nfp_tun_mac_nb);
+	unregister_netevent_notifier(&priv->nfp_tun_neigh_nb);
 
 	/* Free any memory that may be occupied by MAC list. */
 	mutex_lock(&priv->nfp_mac_off_lock);
@@ -491,4 +734,14 @@ void nfp_tunnel_config_stop(struct nfp_app *app)
 		kfree(ip_entry);
 	}
 	mutex_unlock(&priv->nfp_ipv4_off_lock);
+
+	/* Free any memory that may be occupied by the route list. */
+	mutex_lock(&priv->nfp_neigh_off_lock);
+	list_for_each_safe(ptr, storage, &priv->nfp_neigh_off_list) {
+		route_entry = list_entry(ptr, struct nfp_ipv4_route_entry,
+					 list);
+		list_del(&route_entry->list);
+		kfree(route_entry);
+	}
+	mutex_unlock(&priv->nfp_neigh_off_lock);
 }