mlxsw: spectrum_router: Support IPv4 overlay encap

This introduces some common code for tracking of offloaded IP-in-IP
tunnels, and support for offloading IPv4 overlay encapsulating routes in
particular. A follow-up patch will introduce IPv6 overlay as well.

Offloaded tunnels are kept in a linked list of mlxsw_sp_ipip_entry
objects hooked up in mlxsw_sp_router. A network device that represents
the tunnel is used as a key to look up the corresponding IPIP entry.
Note that in the future, more general keying mechanism will be needed,
because parts of the tunnel information can be provided by the route.

IPIP entries are reference counted, because several next hops may end up
using the same tunnel, and we only want to offload it once.

Encapsulation path hooks into next hop handling. Routes that forward to
a tunnel are now considered gateway routes, thus giving them the same
treatment that other remote routes get. An IPIP next hop type is
introduced.

Details of individual tunnel types are kept in an array of
mlxsw_sp_ipip_ops objects. If a tunnel type doesn't match any of the
known tunnel types, the next-hop is not considered an IPIP next hop.

The list of IPIP tunnel types is currently empty, follow-up patches will
add support for GRE. Traffic to IPIP tunnel types that are not
explicitly recognized by the driver traps and is handled in slow path.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 257 insertions, 1 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h
index 65eb493129d9..7b40aa2b049a 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h
@@ -41,9 +41,29 @@ enum mlxsw_sp_ipip_type {
 	MLXSW_SP_IPIP_TYPE_MAX,
 };
 
+struct mlxsw_sp_ipip_entry {
+	enum mlxsw_sp_ipip_type ipipt;
+	struct net_device *ol_dev; /* Overlay. */
+	struct mlxsw_sp_rif_ipip_lb *ol_lb;
+	unsigned int ref_count; /* Number of next hops using the tunnel. */
+	struct list_head ipip_list_node;
+};
+
 struct mlxsw_sp_ipip_ops {
 	int dev_type;
 	enum mlxsw_sp_l3proto ul_proto; /* Underlay. */
+
+	int (*nexthop_update)(struct mlxsw_sp *mlxsw_sp, u32 adj_index,
+			      struct mlxsw_sp_ipip_entry *ipip_entry);
+
+	bool (*can_offload)(const struct mlxsw_sp *mlxsw_sp,
+			    const struct net_device *ol_dev,
+			    enum mlxsw_sp_l3proto ol_proto);
+
+	/* Return a configuration for creating an overlay loopback RIF. */
+	struct mlxsw_sp_rif_ipip_lb_config
+	(*ol_loopback_config)(struct mlxsw_sp *mlxsw_sp,
+			      const struct net_device *ol_dev);
 };
 
 extern const struct mlxsw_sp_ipip_ops *mlxsw_sp_ipip_ops_arr[];
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 53bdd0fdc176..231b597c8c8e 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -89,6 +89,7 @@ struct mlxsw_sp_router {
 	struct delayed_work nexthop_probe_dw;
 #define MLXSW_SP_UNRESOLVED_NH_PROBE_INTERVAL 5000 /* ms */
 	struct list_head nexthop_neighs_list;
+	struct list_head ipip_list;
 	bool aborted;
 	struct notifier_block fib_nb;
 	const struct mlxsw_sp_rif_ops **rif_ops_arr;
@@ -915,6 +916,170 @@ static u32 mlxsw_sp_ipip_dev_ul_tb_id(const struct net_device *ol_dev)
 		return l3mdev_fib_table(ol_dev) ? : RT_TABLE_MAIN;
 }
 
+static struct mlxsw_sp_rif *
+mlxsw_sp_rif_create(struct mlxsw_sp *mlxsw_sp,
+		    const struct mlxsw_sp_rif_params *params);
+
+static struct mlxsw_sp_rif_ipip_lb *
+mlxsw_sp_ipip_ol_ipip_lb_create(struct mlxsw_sp *mlxsw_sp,
+				enum mlxsw_sp_ipip_type ipipt,
+				struct net_device *ol_dev)
+{
+	struct mlxsw_sp_rif_params_ipip_lb lb_params;
+	const struct mlxsw_sp_ipip_ops *ipip_ops;
+	struct mlxsw_sp_rif *rif;
+
+	ipip_ops = mlxsw_sp->router->ipip_ops_arr[ipipt];
+	lb_params = (struct mlxsw_sp_rif_params_ipip_lb) {
+		.common.dev = ol_dev,
+		.common.lag = false,
+		.lb_config = ipip_ops->ol_loopback_config(mlxsw_sp, ol_dev),
+	};
+
+	rif = mlxsw_sp_rif_create(mlxsw_sp, &lb_params.common);
+	if (IS_ERR(rif))
+		return ERR_CAST(rif);
+	return container_of(rif, struct mlxsw_sp_rif_ipip_lb, common);
+}
+
+static struct mlxsw_sp_ipip_entry *
+mlxsw_sp_ipip_entry_alloc(struct mlxsw_sp *mlxsw_sp,
+			  enum mlxsw_sp_ipip_type ipipt,
+			  struct net_device *ol_dev)
+{
+	struct mlxsw_sp_ipip_entry *ipip_entry;
+	struct mlxsw_sp_ipip_entry *ret = NULL;
+
+	ipip_entry = kzalloc(sizeof(*ipip_entry), GFP_KERNEL);
+	if (!ipip_entry)
+		return ERR_PTR(-ENOMEM);
+
+	ipip_entry->ol_lb = mlxsw_sp_ipip_ol_ipip_lb_create(mlxsw_sp, ipipt,
+							    ol_dev);
+	if (IS_ERR(ipip_entry->ol_lb)) {
+		ret = ERR_CAST(ipip_entry->ol_lb);
+		goto err_ol_ipip_lb_create;
+	}
+
+	ipip_entry->ipipt = ipipt;
+	ipip_entry->ol_dev = ol_dev;
+
+	return ipip_entry;
+
+err_ol_ipip_lb_create:
+	kfree(ipip_entry);
+	return ret;
+}
+
+static void
+mlxsw_sp_ipip_entry_destroy(struct mlxsw_sp_ipip_entry *ipip_entry)
+{
+	WARN_ON(ipip_entry->ref_count > 0);
+	mlxsw_sp_rif_destroy(&ipip_entry->ol_lb->common);
+	kfree(ipip_entry);
+}
+
+static __be32
+mlxsw_sp_ipip_netdev_saddr4(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return tun->parms.iph.saddr;
+}
+
+union mlxsw_sp_l3addr
+mlxsw_sp_ipip_netdev_saddr(enum mlxsw_sp_l3proto proto,
+			   const struct net_device *ol_dev)
+{
+	switch (proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		return (union mlxsw_sp_l3addr) {
+			.addr4 = mlxsw_sp_ipip_netdev_saddr4(ol_dev),
+		};
+	case MLXSW_SP_L3_PROTO_IPV6:
+		break;
+	};
+
+	WARN_ON(1);
+	return (union mlxsw_sp_l3addr) {
+		.addr4 = 0,
+	};
+}
+
+static bool mlxsw_sp_l3addr_eq(const union mlxsw_sp_l3addr *addr1,
+			       const union mlxsw_sp_l3addr *addr2)
+{
+	return !memcmp(addr1, addr2, sizeof(*addr1));
+}
+
+static bool
+mlxsw_sp_ipip_entry_saddr_matches(struct mlxsw_sp *mlxsw_sp,
+				  const enum mlxsw_sp_l3proto ul_proto,
+				  union mlxsw_sp_l3addr saddr,
+				  u32 ul_tb_id,
+				  struct mlxsw_sp_ipip_entry *ipip_entry)
+{
+	u32 tun_ul_tb_id = mlxsw_sp_ipip_dev_ul_tb_id(ipip_entry->ol_dev);
+	enum mlxsw_sp_ipip_type ipipt = ipip_entry->ipipt;
+	union mlxsw_sp_l3addr tun_saddr;
+
+	if (mlxsw_sp->router->ipip_ops_arr[ipipt]->ul_proto != ul_proto)
+		return false;
+
+	tun_saddr = mlxsw_sp_ipip_netdev_saddr(ul_proto, ipip_entry->ol_dev);
+	return tun_ul_tb_id == ul_tb_id &&
+	       mlxsw_sp_l3addr_eq(&tun_saddr, &saddr);
+}
+
+static struct mlxsw_sp_ipip_entry *
+mlxsw_sp_ipip_entry_get(struct mlxsw_sp *mlxsw_sp,
+			enum mlxsw_sp_ipip_type ipipt,
+			struct net_device *ol_dev)
+{
+	u32 ul_tb_id = mlxsw_sp_ipip_dev_ul_tb_id(ol_dev);
+	struct mlxsw_sp_router *router = mlxsw_sp->router;
+	struct mlxsw_sp_ipip_entry *ipip_entry;
+	enum mlxsw_sp_l3proto ul_proto;
+	union mlxsw_sp_l3addr saddr;
+
+	list_for_each_entry(ipip_entry, &mlxsw_sp->router->ipip_list,
+			    ipip_list_node) {
+		if (ipip_entry->ol_dev == ol_dev)
+			goto inc_ref_count;
+
+		/* The configuration where several tunnels have the same local
+		 * address in the same underlay table needs special treatment in
+		 * the HW. That is currently not implemented in the driver.
+		 */
+		ul_proto = router->ipip_ops_arr[ipip_entry->ipipt]->ul_proto;
+		saddr = mlxsw_sp_ipip_netdev_saddr(ul_proto, ol_dev);
+		if (mlxsw_sp_ipip_entry_saddr_matches(mlxsw_sp, ul_proto, saddr,
+						      ul_tb_id, ipip_entry))
+			return ERR_PTR(-EEXIST);
+	}
+
+	ipip_entry = mlxsw_sp_ipip_entry_alloc(mlxsw_sp, ipipt, ol_dev);
+	if (IS_ERR(ipip_entry))
+		return ipip_entry;
+
+	list_add_tail(&ipip_entry->ipip_list_node,
+		      &mlxsw_sp->router->ipip_list);
+
+inc_ref_count:
+	++ipip_entry->ref_count;
+	return ipip_entry;
+}
+
+static void
+mlxsw_sp_ipip_entry_put(struct mlxsw_sp *mlxsw_sp,
+			struct mlxsw_sp_ipip_entry *ipip_entry)
+{
+	if (--ipip_entry->ref_count == 0) {
+		list_del(&ipip_entry->ipip_list_node);
+		mlxsw_sp_ipip_entry_destroy(ipip_entry);
+	}
+}
+
 struct mlxsw_sp_neigh_key {
 	struct neighbour *n;
 };
@@ -1654,6 +1819,7 @@ static void mlxsw_sp_neigh_rif_gone_sync(struct mlxsw_sp *mlxsw_sp,
 
 enum mlxsw_sp_nexthop_type {
 	MLXSW_SP_NEXTHOP_TYPE_ETH,
+	MLXSW_SP_NEXTHOP_TYPE_IPIP,
 };
 
 struct mlxsw_sp_nexthop_key {
@@ -1683,6 +1849,7 @@ struct mlxsw_sp_nexthop {
 	enum mlxsw_sp_nexthop_type type;
 	union {
 		struct mlxsw_sp_neigh_entry *neigh_entry;
+		struct mlxsw_sp_ipip_entry *ipip_entry;
 	};
 };
 
@@ -1970,6 +2137,16 @@ static int mlxsw_sp_nexthop_mac_update(struct mlxsw_sp *mlxsw_sp, u32 adj_index,
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ratr), ratr_pl);
 }
 
+static int mlxsw_sp_nexthop_ipip_update(struct mlxsw_sp *mlxsw_sp,
+					u32 adj_index,
+					struct mlxsw_sp_nexthop *nh)
+{
+	const struct mlxsw_sp_ipip_ops *ipip_ops;
+
+	ipip_ops = mlxsw_sp->router->ipip_ops_arr[nh->ipip_entry->ipipt];
+	return ipip_ops->nexthop_update(mlxsw_sp, adj_index, nh->ipip_entry);
+}
+
 static int
 mlxsw_sp_nexthop_group_update(struct mlxsw_sp *mlxsw_sp,
 			      struct mlxsw_sp_nexthop_group *nh_grp,
@@ -1994,6 +2171,10 @@ mlxsw_sp_nexthop_group_update(struct mlxsw_sp *mlxsw_sp,
 				err = mlxsw_sp_nexthop_mac_update
 					    (mlxsw_sp, adj_index, nh);
 				break;
+			case MLXSW_SP_NEXTHOP_TYPE_IPIP:
+				err = mlxsw_sp_nexthop_ipip_update
+					    (mlxsw_sp, adj_index, nh);
+				break;
 			}
 			if (err)
 				return err;
@@ -2297,6 +2478,46 @@ static bool mlxsw_sp_netdev_ipip_type(const struct mlxsw_sp *mlxsw_sp,
 	return false;
 }
 
+static int mlxsw_sp_nexthop_ipip_init(struct mlxsw_sp *mlxsw_sp,
+				      enum mlxsw_sp_ipip_type ipipt,
+				      struct mlxsw_sp_nexthop *nh,
+				      struct net_device *ol_dev)
+{
+	if (!nh->nh_grp->gateway || nh->ipip_entry)
+		return 0;
+
+	nh->ipip_entry = mlxsw_sp_ipip_entry_get(mlxsw_sp, ipipt, ol_dev);
+	if (IS_ERR(nh->ipip_entry))
+		return PTR_ERR(nh->ipip_entry);
+
+	__mlxsw_sp_nexthop_neigh_update(nh, false);
+	return 0;
+}
+
+static void mlxsw_sp_nexthop_ipip_fini(struct mlxsw_sp *mlxsw_sp,
+				       struct mlxsw_sp_nexthop *nh)
+{
+	struct mlxsw_sp_ipip_entry *ipip_entry = nh->ipip_entry;
+
+	if (!ipip_entry)
+		return;
+
+	__mlxsw_sp_nexthop_neigh_update(nh, true);
+	mlxsw_sp_ipip_entry_put(mlxsw_sp, ipip_entry);
+	nh->ipip_entry = NULL;
+}
+
+static bool mlxsw_sp_nexthop4_ipip_type(const struct mlxsw_sp *mlxsw_sp,
+					const struct fib_nh *fib_nh,
+					enum mlxsw_sp_ipip_type *p_ipipt)
+{
+	struct net_device *dev = fib_nh->nh_dev;
+
+	return dev &&
+	       fib_nh->nh_parent->fib_type == RTN_UNICAST &&
+	       mlxsw_sp_netdev_ipip_type(mlxsw_sp, dev, p_ipipt);
+}
+
 static void mlxsw_sp_nexthop_type_fini(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh)
 {
@@ -2305,6 +2526,9 @@ static void mlxsw_sp_nexthop_type_fini(struct mlxsw_sp *mlxsw_sp,
 		mlxsw_sp_nexthop_neigh_fini(mlxsw_sp, nh);
 		mlxsw_sp_nexthop_rif_fini(nh);
 		break;
+	case MLXSW_SP_NEXTHOP_TYPE_IPIP:
+		mlxsw_sp_nexthop_ipip_fini(mlxsw_sp, nh);
+		break;
 	}
 }
 
@@ -2312,10 +2536,19 @@ static int mlxsw_sp_nexthop4_type_init(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh,
 				       struct fib_nh *fib_nh)
 {
+	struct mlxsw_sp_router *router = mlxsw_sp->router;
 	struct net_device *dev = fib_nh->nh_dev;
+	enum mlxsw_sp_ipip_type ipipt;
 	struct mlxsw_sp_rif *rif;
 	int err;
 
+	if (mlxsw_sp_nexthop4_ipip_type(mlxsw_sp, fib_nh, &ipipt) &&
+	    router->ipip_ops_arr[ipipt]->can_offload(mlxsw_sp, dev,
+						     MLXSW_SP_L3_PROTO_IPV4)) {
+		nh->type = MLXSW_SP_NEXTHOP_TYPE_IPIP;
+		return mlxsw_sp_nexthop_ipip_init(mlxsw_sp, ipipt, nh, dev);
+	}
+
 	nh->type = MLXSW_SP_NEXTHOP_TYPE_ETH;
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
 	if (!rif)
@@ -2421,7 +2654,8 @@ static void mlxsw_sp_nexthop_rif_gone_sync(struct mlxsw_sp *mlxsw_sp,
 static bool mlxsw_sp_fi_is_gateway(const struct mlxsw_sp *mlxsw_sp,
 				   const struct fib_info *fi)
 {
-	return fi->fib_nh->nh_scope == RT_SCOPE_LINK;
+	return fi->fib_nh->nh_scope == RT_SCOPE_LINK ||
+	       mlxsw_sp_nexthop4_ipip_type(mlxsw_sp, fi->fib_nh, NULL);
 }
 
 static struct mlxsw_sp_nexthop_group *
@@ -5411,11 +5645,13 @@ static void mlxsw_sp_rifs_fini(struct mlxsw_sp *mlxsw_sp)
 static int mlxsw_sp_ipips_init(struct mlxsw_sp *mlxsw_sp)
 {
 	mlxsw_sp->router->ipip_ops_arr = mlxsw_sp_ipip_ops_arr;
+	INIT_LIST_HEAD(&mlxsw_sp->router->ipip_list);
 	return 0;
 }
 
 static void mlxsw_sp_ipips_fini(struct mlxsw_sp *mlxsw_sp)
 {
+	WARN_ON(!list_empty(&mlxsw_sp->router->ipip_list));
 }
 
 static void mlxsw_sp_router_fib_dump_flush(struct notifier_block *nb)