Re: [RFC net-next 14/15] net/mlx5e: Add Rx data path offload

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Jakub Kicinski wrote:
> From: Raed Salem <raeds@nvidia.com>
> 
> On receive flow inspect received packets for PSP offload indication using
> the cqe, for PSP offloaded packets set SKB PSP metadata i.e spi, header
> length and key generation number to stack for further processing.
> 
> Signed-off-by: Raed Salem <raeds@nvidia.com>
> Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  .../mellanox/mlx5/core/en_accel/ipsec_rxtx.h  |  2 +-
>  .../mellanox/mlx5/core/en_accel/nisp_rxtx.c   | 79 +++++++++++++++++++
>  .../mellanox/mlx5/core/en_accel/nisp_rxtx.h   | 28 +++++++
>  .../net/ethernet/mellanox/mlx5/core/en_rx.c   | 10 +++
>  4 files changed, 118 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.h b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.h
> index 82064614846f..9f025c80a6ef 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.h
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.h
> @@ -40,7 +40,7 @@
>  #include "en/txrx.h"
>  
>  /* Bit31: IPsec marker, Bit30: reserved, Bit29-24: IPsec syndrome, Bit23-0: IPsec obj id */
> -#define MLX5_IPSEC_METADATA_MARKER(metadata)  (((metadata) >> 31) & 0x1)
> +#define MLX5_IPSEC_METADATA_MARKER(metadata)  ((((metadata) >> 30) & 0x3) == 0x2)
>  #define MLX5_IPSEC_METADATA_SYNDROM(metadata) (((metadata) >> 24) & GENMASK(5, 0))
>  #define MLX5_IPSEC_METADATA_HANDLE(metadata)  ((metadata) & GENMASK(23, 0))
>  
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/nisp_rxtx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/nisp_rxtx.c
> index c719b2916677..17f42b8d9fd8 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/nisp_rxtx.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/nisp_rxtx.c
> @@ -15,6 +15,12 @@
>  #include "en_accel/nisp.h"
>  #include "lib/psp_defs.h"
>  
> +enum {
> +	MLX5E_NISP_OFFLOAD_RX_SYNDROME_DECRYPTED,
> +	MLX5E_NISP_OFFLOAD_RX_SYNDROME_AUTH_FAILED,
> +	MLX5E_NISP_OFFLOAD_RX_SYNDROME_BAD_TRAILER,
> +};
> +
>  static void mlx5e_nisp_set_swp(struct sk_buff *skb,
>  			       struct mlx5e_accel_tx_nisp_state *nisp_st,
>  			       struct mlx5_wqe_eth_seg *eseg)
> @@ -114,6 +120,79 @@ static bool mlx5e_nisp_set_state(struct mlx5e_priv *priv,
>  	return ret;
>  }
>  
> +void mlx5e_nisp_csum_complete(struct net_device *netdev, struct sk_buff *skb)
> +{
> +	pskb_trim(skb, skb->len - PSP_TRL_SIZE);
> +}
> +
> +/* Receive handler for PSP packets.
> + *
> + * Presently it accepts only already-authenticated packets and does not
> + * support optional fields, such as virtualization cookies.
> + */
> +static int psp_rcv(struct sk_buff *skb)
> +{
> +	const struct psphdr *psph;
> +	int depth = 0, end_depth;
> +	struct psp_skb_ext *pse;
> +	struct ipv6hdr *ipv6h;
> +	struct ethhdr *eth;
> +	__be16 proto;
> +	u32 spi;
> +
> +	eth = (struct ethhdr *)(skb->data);
> +	proto = __vlan_get_protocol(skb, eth->h_proto, &depth);
> +	if (proto != htons(ETH_P_IPV6))
> +		return -EINVAL;
> +
> +	ipv6h = (struct ipv6hdr *)(skb->data + depth);
> +	depth += sizeof(*ipv6h);
> +	end_depth = depth + sizeof(struct udphdr) + sizeof(struct psphdr);
> +
> +	if (unlikely(end_depth > skb_headlen(skb)))
> +		return -EINVAL;
> +
> +	pse = skb_ext_add(skb, SKB_EXT_PSP);
> +	if (!pse)
> +		return -EINVAL;
> +
> +	psph = (const struct psphdr *)(skb->data + depth + sizeof(struct udphdr));
> +	pse->spi = psph->spi;
> +	spi = ntohl(psph->spi);
> +	pse->generation = 0;
> +	pse->version = FIELD_GET(PSPHDR_VERFL_VERSION, psph->verfl);
> +
> +	ipv6h->nexthdr = psph->nexthdr;
> +	ipv6h->payload_len =
> +		htons(ntohs(ipv6h->payload_len) - PSP_ENCAP_HLEN - PSP_TRL_SIZE);
> +
> +	memmove(skb->data + PSP_ENCAP_HLEN, skb->data, depth);
> +	skb_pull(skb, PSP_ENCAP_HLEN);
> +
> +	return 0;
> +}
> +
> +void mlx5e_nisp_offload_handle_rx_skb(struct net_device *netdev, struct sk_buff *skb,
> +				      struct mlx5_cqe64 *cqe)
> +{
> +	u32 nisp_meta_data = be32_to_cpu(cqe->ft_metadata);
> +
> +	/* TBD: report errors as SW counters to ethtool, any further handling ? */
> +	switch (MLX5_NISP_METADATA_SYNDROM(nisp_meta_data)) {
> +	case MLX5E_NISP_OFFLOAD_RX_SYNDROME_DECRYPTED:
> +		if (psp_rcv(skb))
> +			netdev_warn_once(netdev, "PSP handling failed");
> +		skb->decrypted = 1;

Do not set skb->decrypted if psp_rcv failed? But drop the packet and
account the drop, likely.

> +		break;
> +	case MLX5E_NISP_OFFLOAD_RX_SYNDROME_AUTH_FAILED:
> +		break;
> +	case MLX5E_NISP_OFFLOAD_RX_SYNDROME_BAD_TRAILER:
> +		break;
> +	default:
> +		break;
> +	}
> +}