/*
 * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#include <crypto/internal/geniv.h>
#include <crypto/aead.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/module.h>

#include "en.h"
#include "en_accel/ipsec.h"
#include "en_accel/ipsec_rxtx.h"


static struct mlx5e_ipsec_sa_entry *to_ipsec_sa_entry(struct xfrm_state *x)
{
	struct mlx5e_ipsec_sa_entry *sa;

	if (!x)
		return NULL;

	sa = (struct mlx5e_ipsec_sa_entry *)x->xso.offload_handle;
	if (!sa)
		return NULL;

	WARN_ON(sa->x != x);
	return sa;
}

struct xfrm_state *mlx5e_ipsec_sadb_rx_lookup(struct mlx5e_ipsec *ipsec,
					      unsigned int handle)
{
	struct mlx5e_ipsec_sa_entry *sa_entry;
	struct xfrm_state *ret = NULL;

	rcu_read_lock();
	hash_for_each_possible_rcu(ipsec->sadb_rx, sa_entry, hlist, handle)
		if (sa_entry->handle == handle) {
			ret = sa_entry->x;
			xfrm_state_hold(ret);
			break;
		}
	rcu_read_unlock();

	return ret;
}

static int mlx5e_ipsec_sadb_rx_add(struct mlx5e_ipsec_sa_entry *sa_entry)
{
	struct mlx5e_ipsec *ipsec = sa_entry->ipsec;
	unsigned long flags;
	int ret;

	ret = ida_simple_get(&ipsec->halloc, 1, 0, GFP_KERNEL);
	if (ret < 0)
		return ret;

	spin_lock_irqsave(&ipsec->sadb_rx_lock, flags);
	sa_entry->handle = ret;
	hash_add_rcu(ipsec->sadb_rx, &sa_entry->hlist, sa_entry->handle);
	spin_unlock_irqrestore(&ipsec->sadb_rx_lock, flags);

	return 0;
}

static void mlx5e_ipsec_sadb_rx_del(struct mlx5e_ipsec_sa_entry *sa_entry)
{
	struct mlx5e_ipsec *ipsec = sa_entry->ipsec;
	unsigned long flags;

	spin_lock_irqsave(&ipsec->sadb_rx_lock, flags);
	hash_del_rcu(&sa_entry->hlist);
	spin_unlock_irqrestore(&ipsec->sadb_rx_lock, flags);
}

static void mlx5e_ipsec_sadb_rx_free(struct mlx5e_ipsec_sa_entry *sa_entry)
{
	struct mlx5e_ipsec *ipsec = sa_entry->ipsec;

	/* xfrm already doing sync rcu between del and free callbacks */

	ida_simple_remove(&ipsec->halloc, sa_entry->handle);
}

static bool mlx5e_ipsec_update_esn_state(struct mlx5e_ipsec_sa_entry *sa_entry)
{
	struct xfrm_replay_state_esn *replay_esn;
	u32 seq_bottom;
	u8 overlap;
	u32 *esn;

	if (!(sa_entry->x->props.flags & XFRM_STATE_ESN)) {
		sa_entry->esn_state.trigger = 0;
		return false;
	}

	replay_esn = sa_entry->x->replay_esn;
	seq_bottom = replay_esn->seq - replay_esn->replay_window + 1;
	overlap = sa_entry->esn_state.overlap;

	sa_entry->esn_state.esn = xfrm_replay_seqhi(sa_entry->x,
						    htonl(seq_bottom));
	esn = &sa_entry->esn_state.esn;

	sa_entry->esn_state.trigger = 1;
	if (unlikely(overlap && seq_bottom < MLX5E_IPSEC_ESN_SCOPE_MID)) {
		++(*esn);
		sa_entry->esn_state.overlap = 0;
		return true;
	} else if (unlikely(!overlap &&
			    (seq_bottom >= MLX5E_IPSEC_ESN_SCOPE_MID))) {
		sa_entry->esn_state.overlap = 1;
		return true;
	}

	return false;
}

static void
mlx5e_ipsec_build_accel_xfrm_attrs(struct mlx5e_ipsec_sa_entry *sa_entry,
				   struct mlx5_accel_esp_xfrm_attrs *attrs)
{
	struct xfrm_state *x = sa_entry->x;
	struct aes_gcm_keymat *aes_gcm = &attrs->keymat.aes_gcm;
	struct aead_geniv_ctx *geniv_ctx;
	struct crypto_aead *aead;
	unsigned int crypto_data_len, key_len;
	int ivsize;

	memset(attrs, 0, sizeof(*attrs));

	/* key */
	crypto_data_len = (x->aead->alg_key_len + 7) / 8;
	key_len = crypto_data_len - 4; /* 4 bytes salt at end */

	memcpy(aes_gcm->aes_key, x->aead->alg_key, key_len);
	aes_gcm->key_len = key_len * 8;

	/* salt and seq_iv */
	aead = x->data;
	geniv_ctx = crypto_aead_ctx(aead);
	ivsize = crypto_aead_ivsize(aead);
	memcpy(&aes_gcm->seq_iv, &geniv_ctx->salt, ivsize);
	memcpy(&aes_gcm->salt, x->aead->alg_key + key_len,
	       sizeof(aes_gcm->salt));

	/* iv len */
	aes_gcm->icv_len = x->aead->alg_icv_len;

	/* esn */
	if (sa_entry->esn_state.trigger) {
		attrs->flags |= MLX5_ACCEL_ESP_FLAGS_ESN_TRIGGERED;
		attrs->esn = sa_entry->esn_state.esn;
		if (sa_entry->esn_state.overlap)
			attrs->flags |= MLX5_ACCEL_ESP_FLAGS_ESN_STATE_OVERLAP;
	}

	/* rx handle */
	attrs->sa_handle = sa_entry->handle;

	/* algo type */
	attrs->keymat_type = MLX5_ACCEL_ESP_KEYMAT_AES_GCM;

	/* action */
	attrs->action = (!(x->xso.flags & XFRM_OFFLOAD_INBOUND)) ?
			MLX5_ACCEL_ESP_ACTION_ENCRYPT :
			MLX5_ACCEL_ESP_ACTION_DECRYPT;
	/* flags */
	attrs->flags |= (x->props.mode == XFRM_MODE_TRANSPORT) ?
			MLX5_ACCEL_ESP_FLAGS_TRANSPORT :
			MLX5_ACCEL_ESP_FLAGS_TUNNEL;
}

static inline int mlx5e_xfrm_validate_state(struct xfrm_state *x)
{
	struct net_device *netdev = x->xso.dev;
	struct mlx5e_priv *priv;

	priv = netdev_priv(netdev);

	if (x->props.aalgo != SADB_AALG_NONE) {
		netdev_info(netdev, "Cannot offload authenticated xfrm states\n");
		return -EINVAL;
	}
	if (x->props.ealgo != SADB_X_EALG_AES_GCM_ICV16) {
		netdev_info(netdev, "Only AES-GCM-ICV16 xfrm state may be offloaded\n");
		return -EINVAL;
	}
	if (x->props.calgo != SADB_X_CALG_NONE) {
		netdev_info(netdev, "Cannot offload compressed xfrm states\n");
		return -EINVAL;
	}
	if (x->props.flags & XFRM_STATE_ESN &&
	    !(mlx5_accel_ipsec_device_caps(priv->mdev) &
	    MLX5_ACCEL_IPSEC_CAP_ESN)) {
		netdev_info(netdev, "Cannot offload ESN xfrm states\n");
		return -EINVAL;
	}
	if (x->props.family != AF_INET &&
	    x->props.family != AF_INET6) {
		netdev_info(netdev, "Only IPv4/6 xfrm states may be offloaded\n");
		return -EINVAL;
	}
	if (x->props.mode != XFRM_MODE_TRANSPORT &&
	    x->props.mode != XFRM_MODE_TUNNEL) {
		dev_info(&netdev->dev, "Only transport and tunnel xfrm states may be offloaded\n");
		return -EINVAL;
	}
	if (x->id.proto != IPPROTO_ESP) {
		netdev_info(netdev, "Only ESP xfrm state may be offloaded\n");
		return -EINVAL;
	}
	if (x->encap) {
		netdev_info(netdev, "Encapsulated xfrm state may not be offloaded\n");
		return -EINVAL;
	}
	if (!x->aead) {
		netdev_info(netdev, "Cannot offload xfrm states without aead\n");
		return -EINVAL;
	}
	if (x->aead->alg_icv_len != 128) {
		netdev_info(netdev, "Cannot offload xfrm states with AEAD ICV length other than 128bit\n");
		return -EINVAL;
	}
	if ((x->aead->alg_key_len != 128 + 32) &&
	    (x->aead->alg_key_len != 256 + 32)) {
		netdev_info(netdev, "Cannot offload xfrm states with AEAD key length other than 128/256 bit\n");
		return -EINVAL;
	}
	if (x->tfcpad) {
		netdev_info(netdev, "Cannot offload xfrm states with tfc padding\n");
		return -EINVAL;
	}
	if (!x->geniv) {
		netdev_info(netdev, "Cannot offload xfrm states without geniv\n");
		return -EINVAL;
	}
	if (strcmp(x->geniv, "seqiv")) {
		netdev_info(netdev, "Cannot offload xfrm states with geniv other than seqiv\n");
		return -EINVAL;
	}
	if (x->props.family == AF_INET6 &&
	    !(mlx5_accel_ipsec_device_caps(priv->mdev) &
	     MLX5_ACCEL_IPSEC_CAP_IPV6)) {
		netdev_info(netdev, "IPv6 xfrm state offload is not supported by this device\n");
		return -EINVAL;
	}
	return 0;
}

static int mlx5e_xfrm_add_state(struct xfrm_state *x)
{
	struct mlx5e_ipsec_sa_entry *sa_entry = NULL;
	struct net_device *netdev = x->xso.dev;
	struct mlx5_accel_esp_xfrm_attrs attrs;
	struct mlx5e_priv *priv;
	__be32 saddr[4] = {0}, daddr[4] = {0}, spi;
	bool is_ipv6 = false;
	int err;

	priv = netdev_priv(netdev);

	err = mlx5e_xfrm_validate_state(x);
	if (err)
		return err;

	sa_entry = kzalloc(sizeof(*sa_entry), GFP_KERNEL);
	if (!sa_entry) {
		err = -ENOMEM;
		goto out;
	}

	sa_entry->x = x;
	sa_entry->ipsec = priv->ipsec;

	/* Add the SA to handle processed incoming packets before the add SA
	 * completion was received
	 */
	if (x->xso.flags & XFRM_OFFLOAD_INBOUND) {
		err = mlx5e_ipsec_sadb_rx_add(sa_entry);
		if (err) {
			netdev_info(netdev, "Failed adding to SADB_RX: %d\n", err);
			goto err_entry;
		}
	} else {
		sa_entry->set_iv_op = (x->props.flags & XFRM_STATE_ESN) ?
				mlx5e_ipsec_set_iv_esn : mlx5e_ipsec_set_iv;
	}

	/* check esn */
	mlx5e_ipsec_update_esn_state(sa_entry);

	/* create xfrm */
	mlx5e_ipsec_build_accel_xfrm_attrs(sa_entry, &attrs);
	sa_entry->xfrm =
		mlx5_accel_esp_create_xfrm(priv->mdev, &attrs,
					   MLX5_ACCEL_XFRM_FLAG_REQUIRE_METADATA);
	if (IS_ERR(sa_entry->xfrm)) {
		err = PTR_ERR(sa_entry->xfrm);
		goto err_sadb_rx;
	}

	/* create hw context */
	if (x->props.family == AF_INET) {
		saddr[3] = x->props.saddr.a4;
		daddr[3] = x->id.daddr.a4;
	} else {
		memcpy(saddr, x->props.saddr.a6, sizeof(saddr));
		memcpy(daddr, x->id.daddr.a6, sizeof(daddr));
		is_ipv6 = true;
	}
	spi = x->id.spi;
	sa_entry->hw_context =
			mlx5_accel_esp_create_hw_context(priv->mdev,
							 sa_entry->xfrm,
							 saddr, daddr, spi,
							 is_ipv6);
	if (IS_ERR(sa_entry->hw_context)) {
		err = PTR_ERR(sa_entry->hw_context);
		goto err_xfrm;
	}

	x->xso.offload_handle = (unsigned long)sa_entry;
	goto out;

err_xfrm:
	mlx5_accel_esp_destroy_xfrm(sa_entry->xfrm);
err_sadb_rx:
	if (x->xso.flags & XFRM_OFFLOAD_INBOUND) {
		mlx5e_ipsec_sadb_rx_del(sa_entry);
		mlx5e_ipsec_sadb_rx_free(sa_entry);
	}
err_entry:
	kfree(sa_entry);
out:
	return err;
}

static void mlx5e_xfrm_del_state(struct xfrm_state *x)
{
	struct mlx5e_ipsec_sa_entry *sa_entry = to_ipsec_sa_entry(x);

	if (!sa_entry)
		return;

	if (x->xso.flags & XFRM_OFFLOAD_INBOUND)
		mlx5e_ipsec_sadb_rx_del(sa_entry);
}

static void mlx5e_xfrm_free_state(struct xfrm_state *x)
{
	struct mlx5e_ipsec_sa_entry *sa_entry = to_ipsec_sa_entry(x);

	if (!sa_entry)
		return;

	if (sa_entry->hw_context) {
		flush_workqueue(sa_entry->ipsec->wq);
		mlx5_accel_esp_free_hw_context(sa_entry->hw_context);
		mlx5_accel_esp_destroy_xfrm(sa_entry->xfrm);
	}

	if (x->xso.flags & XFRM_OFFLOAD_INBOUND)
		mlx5e_ipsec_sadb_rx_free(sa_entry);

	kfree(sa_entry);
}

int mlx5e_ipsec_init(struct mlx5e_priv *priv)
{
	struct mlx5e_ipsec *ipsec = NULL;

	if (!MLX5_IPSEC_DEV(priv->mdev)) {
		netdev_dbg(priv->netdev, "Not an IPSec offload device\n");
		return 0;
	}

	ipsec = kzalloc(sizeof(*ipsec), GFP_KERNEL);
	if (!ipsec)
		return -ENOMEM;

	hash_init(ipsec->sadb_rx);
	spin_lock_init(&ipsec->sadb_rx_lock);
	ida_init(&ipsec->halloc);
	ipsec->en_priv = priv;
	ipsec->en_priv->ipsec = ipsec;
	ipsec->no_trailer = !!(mlx5_accel_ipsec_device_caps(priv->mdev) &
			       MLX5_ACCEL_IPSEC_CAP_RX_NO_TRAILER);
	ipsec->wq = alloc_ordered_workqueue("mlx5e_ipsec: %s", 0,
					    priv->netdev->name);
	if (!ipsec->wq) {
		kfree(ipsec);
		return -ENOMEM;
	}
	netdev_dbg(priv->netdev, "IPSec attached to netdevice\n");
	return 0;
}

void mlx5e_ipsec_cleanup(struct mlx5e_priv *priv)
{
	struct mlx5e_ipsec *ipsec = priv->ipsec;

	if (!ipsec)
		return;

	drain_workqueue(ipsec->wq);
	destroy_workqueue(ipsec->wq);

	ida_destroy(&ipsec->halloc);
	kfree(ipsec);
	priv->ipsec = NULL;
}

static bool mlx5e_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
{
	if (x->props.family == AF_INET) {
		/* Offload with IPv4 options is not supported yet */
		if (ip_hdr(skb)->ihl > 5)
			return false;
	} else {
		/* Offload with IPv6 extension headers is not support yet */
		if (ipv6_ext_hdr(ipv6_hdr(skb)->nexthdr))
			return false;
	}

	return true;
}

struct mlx5e_ipsec_modify_state_work {
	struct work_struct		work;
	struct mlx5_accel_esp_xfrm_attrs attrs;
	struct mlx5e_ipsec_sa_entry	*sa_entry;
};

static void _update_xfrm_state(struct work_struct *work)
{
	int ret;
	struct mlx5e_ipsec_modify_state_work *modify_work =
		container_of(work, struct mlx5e_ipsec_modify_state_work, work);
	struct mlx5e_ipsec_sa_entry *sa_entry = modify_work->sa_entry;

	ret = mlx5_accel_esp_modify_xfrm(sa_entry->xfrm,
					 &modify_work->attrs);
	if (ret)
		netdev_warn(sa_entry->ipsec->en_priv->netdev,
			    "Not an IPSec offload device\n");

	kfree(modify_work);
}

static void mlx5e_xfrm_advance_esn_state(struct xfrm_state *x)
{
	struct mlx5e_ipsec_sa_entry *sa_entry = to_ipsec_sa_entry(x);
	struct mlx5e_ipsec_modify_state_work *modify_work;
	bool need_update;

	if (!sa_entry)
		return;

	need_update = mlx5e_ipsec_update_esn_state(sa_entry);
	if (!need_update)
		return;

	modify_work = kzalloc(sizeof(*modify_work), GFP_ATOMIC);
	if (!modify_work)
		return;

	mlx5e_ipsec_build_accel_xfrm_attrs(sa_entry, &modify_work->attrs);
	modify_work->sa_entry = sa_entry;

	INIT_WORK(&modify_work->work, _update_xfrm_state);
	WARN_ON(!queue_work(sa_entry->ipsec->wq, &modify_work->work));
}

static const struct xfrmdev_ops mlx5e_ipsec_xfrmdev_ops = {
	.xdo_dev_state_add	= mlx5e_xfrm_add_state,
	.xdo_dev_state_delete	= mlx5e_xfrm_del_state,
	.xdo_dev_state_free	= mlx5e_xfrm_free_state,
	.xdo_dev_offload_ok	= mlx5e_ipsec_offload_ok,
	.xdo_dev_state_advance_esn = mlx5e_xfrm_advance_esn_state,
};

void mlx5e_ipsec_build_netdev(struct mlx5e_priv *priv)
{
	struct mlx5_core_dev *mdev = priv->mdev;
	struct net_device *netdev = priv->netdev;

	if (!priv->ipsec)
		return;

	if (!(mlx5_accel_ipsec_device_caps(mdev) & MLX5_ACCEL_IPSEC_CAP_ESP) ||
	    !MLX5_CAP_ETH(mdev, swp)) {
		mlx5_core_dbg(mdev, "mlx5e: ESP and SWP offload not supported\n");
		return;
	}

	mlx5_core_info(mdev, "mlx5e: IPSec ESP acceleration enabled\n");
	netdev->xfrmdev_ops = &mlx5e_ipsec_xfrmdev_ops;
	netdev->features |= NETIF_F_HW_ESP;
	netdev->hw_enc_features |= NETIF_F_HW_ESP;

	if (!MLX5_CAP_ETH(mdev, swp_csum)) {
		mlx5_core_dbg(mdev, "mlx5e: SWP checksum not supported\n");
		return;
	}

	netdev->features |= NETIF_F_HW_ESP_TX_CSUM;
	netdev->hw_enc_features |= NETIF_F_HW_ESP_TX_CSUM;

	if (!(mlx5_accel_ipsec_device_caps(mdev) & MLX5_ACCEL_IPSEC_CAP_LSO) ||
	    !MLX5_CAP_ETH(mdev, swp_lso)) {
		mlx5_core_dbg(mdev, "mlx5e: ESP LSO not supported\n");
		return;
	}

	mlx5_core_dbg(mdev, "mlx5e: ESP GSO capability turned on\n");
	netdev->features |= NETIF_F_GSO_ESP;
	netdev->hw_features |= NETIF_F_GSO_ESP;
	netdev->hw_enc_features |= NETIF_F_GSO_ESP;
}