net/mlx5e: Add support for hw encapsulation of MPLS over UDP

MPLS over UDP is supported by adding a rule on a representor net device
which does tunnel_key set, push mpls and forward to a baredup device. At
the hardware level we use a packet_reformat_context object to do the
encapsulation of the packet.

The resulting packet looks as follows (left side transmitted first):
outer L2 | outer IP | UDP | MPLS | inner L3 and data |

Example usage:
  tc filter add dev $rep0 protocol ip prio 1 root flower skip_sw  \
     action tunnel_key set src_ip 8.8.8.21 dst_ip 8.8.8.24 id 555 \
     dst_port 6635 tos 4 ttl 6 csum action mpls push protocol 0x8847 \
     label 555 tc 3 action mirred egress redirect dev bareudp0

This is how the filter is shown with tc filter show:
tc filter show dev enp59s0f0_0 ingress
filter protocol ip pref 1 flower chain 0
filter protocol ip pref 1 flower chain 0 handle 0x1
  eth_type ipv4
  skip_sw
  in_hw in_hw_count 1
        action order 1: tunnel_key  set
        src_ip 8.8.8.21
        dst_ip 8.8.8.24
        key_id 555
        dst_port 6635
        csum
        tos 0x4
        ttl 6 pipe
         index 1 ref 1 bind 1

        action order 2: mpls  push protocol mpls_uc label 555 tc 3 ttl 255 pipe
         index 1 ref 1 bind 1

        action order 3: mirred (Egress Redirect to device bareudp0) stolen
        index 1 ref 1 bind 1

Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Eli Britstein <elibr@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_mplsoudp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_mplsoudp.c
new file mode 100644
index 000000000000..ff296c0a32c4
--- /dev/null
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_mplsoudp.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2018 Mellanox Technologies. */
+
+#include <net/bareudp.h>
+#include <net/mpls.h>
+#include "en/tc_tun.h"
+
+static bool can_offload(struct mlx5e_priv *priv)
+{
+	return MLX5_CAP_ESW_FLOWTABLE_FDB(priv->mdev, reformat_l3_tunnel_to_l2);
+}
+
+static int calc_hlen(struct mlx5e_encap_entry *e)
+{
+	return sizeof(struct udphdr) + MPLS_HLEN;
+}
+
+static int init_encap_attr(struct net_device *tunnel_dev,
+			   struct mlx5e_priv *priv,
+			   struct mlx5e_encap_entry *e,
+			   struct netlink_ext_ack *extack)
+{
+	e->tunnel = &mplsoudp_tunnel;
+	e->reformat_type = MLX5_REFORMAT_TYPE_L2_TO_L3_TUNNEL;
+	return 0;
+}
+
+static inline __be32 mpls_label_id_field(__be32 label, u8 tos, u8 ttl)
+{
+	u32 res;
+
+	/* mpls label is 32 bits long and construction as follows:
+	 * 20 bits label
+	 * 3 bits tos
+	 * 1 bit bottom of stack. Since we support only one label, this bit is
+	 *       always set.
+	 * 8 bits TTL
+	 */
+	res = be32_to_cpu(label) << 12 | 1 << 8 | (tos & 7) <<  9 | ttl;
+	return cpu_to_be32(res);
+}
+
+static int generate_ip_tun_hdr(char buf[],
+			       __u8 *ip_proto,
+			       struct mlx5e_encap_entry *r)
+{
+	const struct ip_tunnel_key *tun_key = &r->tun_info->key;
+	__be32 tun_id = tunnel_id_to_key32(tun_key->tun_id);
+	struct udphdr *udp = (struct udphdr *)(buf);
+	struct mpls_shim_hdr *mpls;
+
+	mpls = (struct mpls_shim_hdr *)(udp + 1);
+	*ip_proto = IPPROTO_UDP;
+
+	udp->dest = tun_key->tp_dst;
+	mpls->label_stack_entry = mpls_label_id_field(tun_id, tun_key->tos, tun_key->ttl);
+
+	return 0;
+}
+
+static int parse_udp_ports(struct mlx5e_priv *priv,
+			   struct mlx5_flow_spec *spec,
+			   struct flow_cls_offload *f,
+			   void *headers_c,
+			   void *headers_v)
+{
+	return mlx5e_tc_tun_parse_udp_ports(priv, spec, f, headers_c, headers_v);
+}
+
+static int parse_tunnel(struct mlx5e_priv *priv,
+			struct mlx5_flow_spec *spec,
+			struct flow_cls_offload *f,
+			void *headers_c,
+			void *headers_v)
+{
+	return 0;
+}
+
+struct mlx5e_tc_tunnel mplsoudp_tunnel = {
+	.tunnel_type          = MLX5E_TC_TUNNEL_TYPE_MPLSOUDP,
+	.match_level          = MLX5_MATCH_L4,
+	.can_offload          = can_offload,
+	.calc_hlen            = calc_hlen,
+	.init_encap_attr      = init_encap_attr,
+	.generate_ip_tun_hdr  = generate_ip_tun_hdr,
+	.parse_udp_ports      = parse_udp_ports,
+	.parse_tunnel         = parse_tunnel,
+};