mlxsw: spectrum_router: Support GRE tunnels

This patch introduces callbacks and tunnel type to offload GRE tunnels.
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>

drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.c

@@ -32,7 +32,183 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <net/ip_tunnels.h>
+
 #include "spectrum_ipip.h"
 
+static bool
+mlxsw_sp_ipip_netdev_has_ikey(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return !!(tun->parms.i_flags & TUNNEL_KEY);
+}
+
+static bool
+mlxsw_sp_ipip_netdev_has_okey(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return !!(tun->parms.o_flags & TUNNEL_KEY);
+}
+
+static u32 mlxsw_sp_ipip_netdev_ikey(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return mlxsw_sp_ipip_netdev_has_ikey(ol_dev) ?
+		be32_to_cpu(tun->parms.i_key) : 0;
+}
+
+static u32 mlxsw_sp_ipip_netdev_okey(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return mlxsw_sp_ipip_netdev_has_okey(ol_dev) ?
+		be32_to_cpu(tun->parms.o_key) : 0;
+}
+
+static int
+mlxsw_sp_ipip_nexthop_update_gre4(struct mlxsw_sp *mlxsw_sp, u32 adj_index,
+				  struct mlxsw_sp_ipip_entry *ipip_entry)
+{
+	u16 rif_index = mlxsw_sp_ipip_lb_rif_index(ipip_entry->ol_lb);
+	__be32 daddr4 = mlxsw_sp_ipip_netdev_daddr4(ipip_entry->ol_dev);
+	char ratr_pl[MLXSW_REG_RATR_LEN];
+
+	mlxsw_reg_ratr_pack(ratr_pl, MLXSW_REG_RATR_OP_WRITE_WRITE_ENTRY,
+			    true, MLXSW_REG_RATR_TYPE_IPIP,
+			    adj_index, rif_index);
+	mlxsw_reg_ratr_ipip4_entry_pack(ratr_pl, be32_to_cpu(daddr4));
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ratr), ratr_pl);
+}
+
+static int
+mlxsw_sp_ipip_fib_entry_op_gre4_rtdp(struct mlxsw_sp *mlxsw_sp,
+				     u32 tunnel_index,
+				     struct mlxsw_sp_ipip_entry *ipip_entry)
+{
+	bool has_ikey = mlxsw_sp_ipip_netdev_has_ikey(ipip_entry->ol_dev);
+	u16 rif_index = mlxsw_sp_ipip_lb_rif_index(ipip_entry->ol_lb);
+	u32 ikey = mlxsw_sp_ipip_netdev_ikey(ipip_entry->ol_dev);
+	char rtdp_pl[MLXSW_REG_RTDP_LEN];
+	unsigned int type_check;
+	u32 daddr4;
+
+	mlxsw_reg_rtdp_pack(rtdp_pl, MLXSW_REG_RTDP_TYPE_IPIP, tunnel_index);
+
+	type_check = has_ikey ?
+		MLXSW_REG_RTDP_IPIP_TYPE_CHECK_ALLOW_GRE_KEY :
+		MLXSW_REG_RTDP_IPIP_TYPE_CHECK_ALLOW_GRE;
+
+	/* Linux demuxes tunnels based on packet SIP (which must match tunnel
+	 * remote IP). Thus configure decap so that it filters out packets that
+	 * are not IPv4 or have the wrong SIP. IPIP_DECAP_ERROR trap is
+	 * generated for packets that fail this criterion. Linux then handles
+	 * such packets in slow path and generates ICMP destination unreachable.
+	 */
+	daddr4 = be32_to_cpu(mlxsw_sp_ipip_netdev_daddr4(ipip_entry->ol_dev));
+	mlxsw_reg_rtdp_ipip4_pack(rtdp_pl, rif_index,
+				  MLXSW_REG_RTDP_IPIP_SIP_CHECK_FILTER_IPV4,
+				  type_check, has_ikey, daddr4, ikey);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(rtdp), rtdp_pl);
+}
+
+static int
+mlxsw_sp_ipip_fib_entry_op_gre4_ralue(struct mlxsw_sp *mlxsw_sp,
+				      u32 dip, u8 prefix_len, u16 ul_vr_id,
+				      enum mlxsw_reg_ralue_op op,
+				      u32 tunnel_index)
+{
+	char ralue_pl[MLXSW_REG_RALUE_LEN];
+
+	mlxsw_reg_ralue_pack4(ralue_pl, MLXSW_REG_RALXX_PROTOCOL_IPV4, op,
+			      ul_vr_id, prefix_len, dip);
+	mlxsw_reg_ralue_act_ip2me_tun_pack(ralue_pl, tunnel_index);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
+}
+
+static int mlxsw_sp_ipip_fib_entry_op_gre4(struct mlxsw_sp *mlxsw_sp,
+					struct mlxsw_sp_ipip_entry *ipip_entry,
+					enum mlxsw_reg_ralue_op op,
+					u32 tunnel_index)
+{
+	u16 ul_vr_id = mlxsw_sp_ipip_lb_ul_vr_id(ipip_entry->ol_lb);
+	__be32 dip;
+	int err;
+
+	err = mlxsw_sp_ipip_fib_entry_op_gre4_rtdp(mlxsw_sp, tunnel_index,
+						   ipip_entry);
+	if (err)
+		return err;
+
+	dip = mlxsw_sp_ipip_netdev_saddr(MLXSW_SP_L3_PROTO_IPV4,
+					 ipip_entry->ol_dev).addr4;
+	return mlxsw_sp_ipip_fib_entry_op_gre4_ralue(mlxsw_sp, be32_to_cpu(dip),
+						     32, ul_vr_id, op,
+						     tunnel_index);
+}
+
+static bool mlxsw_sp_ipip_tunnel_complete(enum mlxsw_sp_l3proto proto,
+					  const struct net_device *ol_dev)
+{
+	union mlxsw_sp_l3addr saddr = mlxsw_sp_ipip_netdev_saddr(proto, ol_dev);
+	union mlxsw_sp_l3addr daddr = mlxsw_sp_ipip_netdev_daddr(proto, ol_dev);
+	union mlxsw_sp_l3addr naddr = {0};
+
+	/* Tunnels with unset local or remote address are valid in Linux and
+	 * used for lightweight tunnels (LWT) and Non-Broadcast Multi-Access
+	 * (NBMA) tunnels. In principle these can be offloaded, but the driver
+	 * currently doesn't support this. So punt.
+	 */
+	return memcmp(&saddr, &naddr, sizeof(naddr)) &&
+	       memcmp(&daddr, &naddr, sizeof(naddr));
+}
+
+static bool mlxsw_sp_ipip_can_offload_gre4(const struct mlxsw_sp *mlxsw_sp,
+					   const struct net_device *ol_dev,
+					   enum mlxsw_sp_l3proto ol_proto)
+{
+	struct ip_tunnel *tunnel = netdev_priv(ol_dev);
+	__be16 okflags = TUNNEL_KEY; /* We can't offload any other features. */
+	bool inherit_ttl = tunnel->parms.iph.ttl == 0;
+	bool inherit_tos = tunnel->parms.iph.tos & 0x1;
+
+	return (tunnel->parms.i_flags & ~okflags) == 0 &&
+	       (tunnel->parms.o_flags & ~okflags) == 0 &&
+	       inherit_ttl && inherit_tos &&
+	       mlxsw_sp_ipip_tunnel_complete(MLXSW_SP_L3_PROTO_IPV4, ol_dev);
+}
+
+static struct mlxsw_sp_rif_ipip_lb_config
+mlxsw_sp_ipip_ol_loopback_config_gre4(struct mlxsw_sp *mlxsw_sp,
+				      const struct net_device *ol_dev)
+{
+	enum mlxsw_reg_ritr_loopback_ipip_type lb_ipipt;
+
+	lb_ipipt = mlxsw_sp_ipip_netdev_has_okey(ol_dev) ?
+		MLXSW_REG_RITR_LOOPBACK_IPIP_TYPE_IP_IN_GRE_KEY_IN_IP :
+		MLXSW_REG_RITR_LOOPBACK_IPIP_TYPE_IP_IN_GRE_IN_IP;
+	return (struct mlxsw_sp_rif_ipip_lb_config){
+		.lb_ipipt = lb_ipipt,
+		.okey = mlxsw_sp_ipip_netdev_okey(ol_dev),
+		.ul_protocol = MLXSW_SP_L3_PROTO_IPV4,
+		.saddr = mlxsw_sp_ipip_netdev_saddr(MLXSW_SP_L3_PROTO_IPV4,
+						    ol_dev),
+	};
+}
+
+static const struct mlxsw_sp_ipip_ops mlxsw_sp_ipip_gre4_ops = {
+	.dev_type = ARPHRD_IPGRE,
+	.ul_proto = MLXSW_SP_L3_PROTO_IPV4,
+	.nexthop_update = mlxsw_sp_ipip_nexthop_update_gre4,
+	.fib_entry_op = mlxsw_sp_ipip_fib_entry_op_gre4,
+	.can_offload = mlxsw_sp_ipip_can_offload_gre4,
+	.ol_loopback_config = mlxsw_sp_ipip_ol_loopback_config_gre4,
+};
+
 const struct mlxsw_sp_ipip_ops *mlxsw_sp_ipip_ops_arr[] = {
+	[MLXSW_SP_IPIP_TYPE_GRE4] = &mlxsw_sp_ipip_gre4_ops,
 };

drivers/net/ethernet/mellanox/mlxsw/spectrum_ipip.h

@@ -39,6 +39,7 @@
 #include <net/ip_fib.h>
 
 enum mlxsw_sp_ipip_type {
+	MLXSW_SP_IPIP_TYPE_GRE4,
 	MLXSW_SP_IPIP_TYPE_MAX,
 };
 

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -1020,6 +1020,32 @@ mlxsw_sp_ipip_netdev_saddr(enum mlxsw_sp_l3proto proto,
 	};
 }
 
+__be32 mlxsw_sp_ipip_netdev_daddr4(const struct net_device *ol_dev)
+{
+	struct ip_tunnel *tun = netdev_priv(ol_dev);
+
+	return tun->parms.iph.daddr;
+}
+
+union mlxsw_sp_l3addr
+mlxsw_sp_ipip_netdev_daddr(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_daddr4(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)
 {

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.h

@@ -103,5 +103,9 @@ bool mlxsw_sp_neigh_ipv6_ignore(struct mlxsw_sp_neigh_entry *neigh_entry);
 union mlxsw_sp_l3addr
 mlxsw_sp_ipip_netdev_saddr(enum mlxsw_sp_l3proto proto,
 			   const struct net_device *ol_dev);
+union mlxsw_sp_l3addr
+mlxsw_sp_ipip_netdev_daddr(enum mlxsw_sp_l3proto proto,
+			   const struct net_device *ol_dev);
+__be32 mlxsw_sp_ipip_netdev_daddr4(const struct net_device *ol_dev);
 
 #endif /* _MLXSW_ROUTER_H_*/