/*******************************************************************************
 *
 * Intel 10 Gigabit PCI Express Linux driver
 * Copyright(c) 2017 Oracle and/or its affiliates. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * Linux NICS <linux.nics@intel.com>
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 ******************************************************************************/

#include "ixgbe.h"
#include <net/xfrm.h>
#include <crypto/aead.h>

/**
 * ixgbe_ipsec_set_tx_sa - set the Tx SA registers
 * @hw: hw specific details
 * @idx: register index to write
 * @key: key byte array
 * @salt: salt bytes
 **/
static void ixgbe_ipsec_set_tx_sa(struct ixgbe_hw *hw, u16 idx,
                                  u32 key[], u32 salt)
{
        u32 reg;
        int i;

        for (i = 0; i < 4; i++)
                IXGBE_WRITE_REG(hw, IXGBE_IPSTXKEY(i), cpu_to_be32(key[3 - i]));
        IXGBE_WRITE_REG(hw, IXGBE_IPSTXSALT, cpu_to_be32(salt));
        IXGBE_WRITE_FLUSH(hw);

        reg = IXGBE_READ_REG(hw, IXGBE_IPSTXIDX);
        reg &= IXGBE_RXTXIDX_IPS_EN;
        reg |= idx << IXGBE_RXTXIDX_IDX_SHIFT | IXGBE_RXTXIDX_WRITE;
        IXGBE_WRITE_REG(hw, IXGBE_IPSTXIDX, reg);
        IXGBE_WRITE_FLUSH(hw);
}

/**
 * ixgbe_ipsec_set_rx_item - set an Rx table item
 * @hw: hw specific details
 * @idx: register index to write
 * @tbl: table selector
 *
 * Trigger the device to store into a particular Rx table the
 * data that has already been loaded into the input register
 **/
static void ixgbe_ipsec_set_rx_item(struct ixgbe_hw *hw, u16 idx,
                                    enum ixgbe_ipsec_tbl_sel tbl)
{
        u32 reg;

        reg = IXGBE_READ_REG(hw, IXGBE_IPSRXIDX);
        reg &= IXGBE_RXTXIDX_IPS_EN;
        reg |= tbl << IXGBE_RXIDX_TBL_SHIFT |
               idx << IXGBE_RXTXIDX_IDX_SHIFT |
               IXGBE_RXTXIDX_WRITE;
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXIDX, reg);
        IXGBE_WRITE_FLUSH(hw);
}

/**
 * ixgbe_ipsec_set_rx_sa - set up the register bits to save SA info
 * @hw: hw specific details
 * @idx: register index to write
 * @spi: security parameter index
 * @key: key byte array
 * @salt: salt bytes
 * @mode: rx decrypt control bits
 * @ip_idx: index into IP table for related IP address
 **/
static void ixgbe_ipsec_set_rx_sa(struct ixgbe_hw *hw, u16 idx, __be32 spi,
                                  u32 key[], u32 salt, u32 mode, u32 ip_idx)
{
        int i;

        /* store the SPI (in bigendian) and IPidx */
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXSPI, cpu_to_le32(spi));
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXIPIDX, ip_idx);
        IXGBE_WRITE_FLUSH(hw);

        ixgbe_ipsec_set_rx_item(hw, idx, ips_rx_spi_tbl);

        /* store the key, salt, and mode */
        for (i = 0; i < 4; i++)
                IXGBE_WRITE_REG(hw, IXGBE_IPSRXKEY(i), cpu_to_be32(key[3 - i]));
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXSALT, cpu_to_be32(salt));
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXMOD, mode);
        IXGBE_WRITE_FLUSH(hw);

        ixgbe_ipsec_set_rx_item(hw, idx, ips_rx_key_tbl);
}

/**
 * ixgbe_ipsec_set_rx_ip - set up the register bits to save SA IP addr info
 * @hw: hw specific details
 * @idx: register index to write
 * @addr: IP address byte array
 **/
static void ixgbe_ipsec_set_rx_ip(struct ixgbe_hw *hw, u16 idx, __be32 addr[])
{
        int i;

        /* store the ip address */
        for (i = 0; i < 4; i++)
                IXGBE_WRITE_REG(hw, IXGBE_IPSRXIPADDR(i), cpu_to_le32(addr[i]));
        IXGBE_WRITE_FLUSH(hw);

        ixgbe_ipsec_set_rx_item(hw, idx, ips_rx_ip_tbl);
}

/**
 * ixgbe_ipsec_clear_hw_tables - because some tables don't get cleared on reset
 * @adapter: board private structure
 **/
static void ixgbe_ipsec_clear_hw_tables(struct ixgbe_adapter *adapter)
{
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct ixgbe_hw *hw = &adapter->hw;
        u32 buf[4] = {0, 0, 0, 0};
        u16 idx;

        /* disable Rx and Tx SA lookup */
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXIDX, 0);
        IXGBE_WRITE_REG(hw, IXGBE_IPSTXIDX, 0);

        /* scrub the tables - split the loops for the max of the IP table */
        for (idx = 0; idx < IXGBE_IPSEC_MAX_RX_IP_COUNT; idx++) {
                ixgbe_ipsec_set_tx_sa(hw, idx, buf, 0);
                ixgbe_ipsec_set_rx_sa(hw, idx, 0, buf, 0, 0, 0);
                ixgbe_ipsec_set_rx_ip(hw, idx, (__be32 *)buf);
        }
        for (; idx < IXGBE_IPSEC_MAX_SA_COUNT; idx++) {
                ixgbe_ipsec_set_tx_sa(hw, idx, buf, 0);
                ixgbe_ipsec_set_rx_sa(hw, idx, 0, buf, 0, 0, 0);
        }

        ipsec->num_rx_sa = 0;
        ipsec->num_tx_sa = 0;
}

/**
 * ixgbe_ipsec_stop_data
 * @adapter: board private structure
 **/
static void ixgbe_ipsec_stop_data(struct ixgbe_adapter *adapter)
{
        struct ixgbe_hw *hw = &adapter->hw;
        bool link = adapter->link_up;
        u32 t_rdy, r_rdy;
        u32 limit;
        u32 reg;

        /* halt data paths */
        reg = IXGBE_READ_REG(hw, IXGBE_SECTXCTRL);
        reg |= IXGBE_SECTXCTRL_TX_DIS;
        IXGBE_WRITE_REG(hw, IXGBE_SECTXCTRL, reg);

        reg = IXGBE_READ_REG(hw, IXGBE_SECRXCTRL);
        reg |= IXGBE_SECRXCTRL_RX_DIS;
        IXGBE_WRITE_REG(hw, IXGBE_SECRXCTRL, reg);

        IXGBE_WRITE_FLUSH(hw);

        /* If the tx fifo doesn't have link, but still has data,
         * we can't clear the tx sec block.  Set the MAC loopback
         * before block clear
         */
        if (!link) {
                reg = IXGBE_READ_REG(hw, IXGBE_MACC);
                reg |= IXGBE_MACC_FLU;
                IXGBE_WRITE_REG(hw, IXGBE_MACC, reg);

                reg = IXGBE_READ_REG(hw, IXGBE_HLREG0);
                reg |= IXGBE_HLREG0_LPBK;
                IXGBE_WRITE_REG(hw, IXGBE_HLREG0, reg);

                IXGBE_WRITE_FLUSH(hw);
                mdelay(3);
        }

        /* wait for the paths to empty */
        limit = 20;
        do {
                mdelay(10);
                t_rdy = IXGBE_READ_REG(hw, IXGBE_SECTXSTAT) &
                        IXGBE_SECTXSTAT_SECTX_RDY;
                r_rdy = IXGBE_READ_REG(hw, IXGBE_SECRXSTAT) &
                        IXGBE_SECRXSTAT_SECRX_RDY;
        } while (!t_rdy && !r_rdy && limit--);

        /* undo loopback if we played with it earlier */
        if (!link) {
                reg = IXGBE_READ_REG(hw, IXGBE_MACC);
                reg &= ~IXGBE_MACC_FLU;
                IXGBE_WRITE_REG(hw, IXGBE_MACC, reg);

                reg = IXGBE_READ_REG(hw, IXGBE_HLREG0);
                reg &= ~IXGBE_HLREG0_LPBK;
                IXGBE_WRITE_REG(hw, IXGBE_HLREG0, reg);

                IXGBE_WRITE_FLUSH(hw);
        }
}

/**
 * ixgbe_ipsec_stop_engine
 * @adapter: board private structure
 **/
static void ixgbe_ipsec_stop_engine(struct ixgbe_adapter *adapter)
{
        struct ixgbe_hw *hw = &adapter->hw;
        u32 reg;

        ixgbe_ipsec_stop_data(adapter);

        /* disable Rx and Tx SA lookup */
        IXGBE_WRITE_REG(hw, IXGBE_IPSTXIDX, 0);
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXIDX, 0);

        /* disable the Rx and Tx engines and full packet store-n-forward */
        reg = IXGBE_READ_REG(hw, IXGBE_SECTXCTRL);
        reg |= IXGBE_SECTXCTRL_SECTX_DIS;
        reg &= ~IXGBE_SECTXCTRL_STORE_FORWARD;
        IXGBE_WRITE_REG(hw, IXGBE_SECTXCTRL, reg);

        reg = IXGBE_READ_REG(hw, IXGBE_SECRXCTRL);
        reg |= IXGBE_SECRXCTRL_SECRX_DIS;
        IXGBE_WRITE_REG(hw, IXGBE_SECRXCTRL, reg);

        /* restore the "tx security buffer almost full threshold" to 0x250 */
        IXGBE_WRITE_REG(hw, IXGBE_SECTXBUFFAF, 0x250);

        /* Set minimum IFG between packets back to the default 0x1 */
        reg = IXGBE_READ_REG(hw, IXGBE_SECTXMINIFG);
        reg = (reg & 0xfffffff0) | 0x1;
        IXGBE_WRITE_REG(hw, IXGBE_SECTXMINIFG, reg);

        /* final set for normal (no ipsec offload) processing */
        IXGBE_WRITE_REG(hw, IXGBE_SECTXCTRL, IXGBE_SECTXCTRL_SECTX_DIS);
        IXGBE_WRITE_REG(hw, IXGBE_SECRXCTRL, IXGBE_SECRXCTRL_SECRX_DIS);

        IXGBE_WRITE_FLUSH(hw);
}

/**
 * ixgbe_ipsec_start_engine
 * @adapter: board private structure
 *
 * NOTE: this increases power consumption whether being used or not
 **/
static void ixgbe_ipsec_start_engine(struct ixgbe_adapter *adapter)
{
        struct ixgbe_hw *hw = &adapter->hw;
        u32 reg;

        ixgbe_ipsec_stop_data(adapter);

        /* Set minimum IFG between packets to 3 */
        reg = IXGBE_READ_REG(hw, IXGBE_SECTXMINIFG);
        reg = (reg & 0xfffffff0) | 0x3;
        IXGBE_WRITE_REG(hw, IXGBE_SECTXMINIFG, reg);

        /* Set "tx security buffer almost full threshold" to 0x15 so that the
         * almost full indication is generated only after buffer contains at
         * least an entire jumbo packet.
         */
        reg = IXGBE_READ_REG(hw, IXGBE_SECTXBUFFAF);
        reg = (reg & 0xfffffc00) | 0x15;
        IXGBE_WRITE_REG(hw, IXGBE_SECTXBUFFAF, reg);

        /* restart the data paths by clearing the DISABLE bits */
        IXGBE_WRITE_REG(hw, IXGBE_SECRXCTRL, 0);
        IXGBE_WRITE_REG(hw, IXGBE_SECTXCTRL, IXGBE_SECTXCTRL_STORE_FORWARD);

        /* enable Rx and Tx SA lookup */
        IXGBE_WRITE_REG(hw, IXGBE_IPSTXIDX, IXGBE_RXTXIDX_IPS_EN);
        IXGBE_WRITE_REG(hw, IXGBE_IPSRXIDX, IXGBE_RXTXIDX_IPS_EN);

        IXGBE_WRITE_FLUSH(hw);
}

/**
 * ixgbe_ipsec_restore - restore the ipsec HW settings after a reset
 * @adapter: board private structure
 **/
void ixgbe_ipsec_restore(struct ixgbe_adapter *adapter)
{
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct ixgbe_hw *hw = &adapter->hw;
        int i;

        if (!(adapter->flags2 & IXGBE_FLAG2_IPSEC_ENABLED))
                return;

        /* clean up and restart the engine */
        ixgbe_ipsec_stop_engine(adapter);
        ixgbe_ipsec_clear_hw_tables(adapter);
        ixgbe_ipsec_start_engine(adapter);

        /* reload the IP addrs */
        for (i = 0; i < IXGBE_IPSEC_MAX_RX_IP_COUNT; i++) {
                struct rx_ip_sa *ipsa = &ipsec->ip_tbl[i];

                if (ipsa->used)
                        ixgbe_ipsec_set_rx_ip(hw, i, ipsa->ipaddr);
        }

        /* reload the Rx and Tx keys */
        for (i = 0; i < IXGBE_IPSEC_MAX_SA_COUNT; i++) {
                struct rx_sa *rsa = &ipsec->rx_tbl[i];
                struct tx_sa *tsa = &ipsec->tx_tbl[i];

                if (rsa->used)
                        ixgbe_ipsec_set_rx_sa(hw, i, rsa->xs->id.spi,
                                              rsa->key, rsa->salt,
                                              rsa->mode, rsa->iptbl_ind);

                if (tsa->used)
                        ixgbe_ipsec_set_tx_sa(hw, i, tsa->key, tsa->salt);
        }
}

/**
 * ixgbe_ipsec_find_empty_idx - find the first unused security parameter index
 * @ipsec: pointer to ipsec struct
 * @rxtable: true if we need to look in the Rx table
 *
 * Returns the first unused index in either the Rx or Tx SA table
 **/
static int ixgbe_ipsec_find_empty_idx(struct ixgbe_ipsec *ipsec, bool rxtable)
{
        u32 i;

        if (rxtable) {
                if (ipsec->num_rx_sa == IXGBE_IPSEC_MAX_SA_COUNT)
                        return -ENOSPC;

                /* search rx sa table */
                for (i = 0; i < IXGBE_IPSEC_MAX_SA_COUNT; i++) {
                        if (!ipsec->rx_tbl[i].used)
                                return i;
                }
        } else {
                if (ipsec->num_tx_sa == IXGBE_IPSEC_MAX_SA_COUNT)
                        return -ENOSPC;

                /* search tx sa table */
                for (i = 0; i < IXGBE_IPSEC_MAX_SA_COUNT; i++) {
                        if (!ipsec->tx_tbl[i].used)
                                return i;
                }
        }

        return -ENOSPC;
}

/**
 * ixgbe_ipsec_find_rx_state - find the state that matches
 * @ipsec: pointer to ipsec struct
 * @daddr: inbound address to match
 * @proto: protocol to match
 * @spi: SPI to match
 * @ip4: true if using an ipv4 address
 *
 * Returns a pointer to the matching SA state information
 **/
static struct xfrm_state *ixgbe_ipsec_find_rx_state(struct ixgbe_ipsec *ipsec,
                                                    __be32 *daddr, u8 proto,
                                                    __be32 spi, bool ip4)
{
        struct rx_sa *rsa;
        struct xfrm_state *ret = NULL;

        rcu_read_lock();
        hash_for_each_possible_rcu(ipsec->rx_sa_list, rsa, hlist, spi)
                if (spi == rsa->xs->id.spi &&
                    ((ip4 && *daddr == rsa->xs->id.daddr.a4) ||
                      (!ip4 && !memcmp(daddr, &rsa->xs->id.daddr.a6,
                                       sizeof(rsa->xs->id.daddr.a6)))) &&
                    proto == rsa->xs->id.proto) {
                        ret = rsa->xs;
                        xfrm_state_hold(ret);
                        break;
                }
        rcu_read_unlock();
        return ret;
}

/**
 * ixgbe_ipsec_parse_proto_keys - find the key and salt based on the protocol
 * @xs: pointer to xfrm_state struct
 * @mykey: pointer to key array to populate
 * @mysalt: pointer to salt value to populate
 *
 * This copies the protocol keys and salt to our own data tables.  The
 * 82599 family only supports the one algorithm.
 **/
static int ixgbe_ipsec_parse_proto_keys(struct xfrm_state *xs,
                                        u32 *mykey, u32 *mysalt)
{
        struct net_device *dev = xs->xso.dev;
        unsigned char *key_data;
        char *alg_name = NULL;
        const char aes_gcm_name[] = "rfc4106(gcm(aes))";
        int key_len;

        if (!xs->aead) {
                netdev_err(dev, "Unsupported IPsec algorithm\n");
                return -EINVAL;
        }

        if (xs->aead->alg_icv_len != IXGBE_IPSEC_AUTH_BITS) {
                netdev_err(dev, "IPsec offload requires %d bit authentication\n",
                           IXGBE_IPSEC_AUTH_BITS);
                return -EINVAL;
        }

        key_data = &xs->aead->alg_key[0];
        key_len = xs->aead->alg_key_len;
        alg_name = xs->aead->alg_name;

        if (strcmp(alg_name, aes_gcm_name)) {
                netdev_err(dev, "Unsupported IPsec algorithm - please use %s\n",
                           aes_gcm_name);
                return -EINVAL;
        }

        /* The key bytes come down in a bigendian array of bytes, so
         * we don't need to do any byteswapping.
         * 160 accounts for 16 byte key and 4 byte salt
         */
        if (key_len == 160) {
                *mysalt = ((u32 *)key_data)[4];
        } else if (key_len != 128) {
                netdev_err(dev, "IPsec hw offload only supports keys up to 128 bits with a 32 bit salt\n");
                return -EINVAL;
        } else {
                netdev_info(dev, "IPsec hw offload parameters missing 32 bit salt value\n");
                *mysalt = 0;
        }
        memcpy(mykey, key_data, 16);

        return 0;
}

/**
 * ixgbe_ipsec_add_sa - program device with a security association
 * @xs: pointer to transformer state struct
 **/
static int ixgbe_ipsec_add_sa(struct xfrm_state *xs)
{
        struct net_device *dev = xs->xso.dev;
        struct ixgbe_adapter *adapter = netdev_priv(dev);
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct ixgbe_hw *hw = &adapter->hw;
        int checked, match, first;
        u16 sa_idx;
        int ret;
        int i;

        if (xs->id.proto != IPPROTO_ESP && xs->id.proto != IPPROTO_AH) {
                netdev_err(dev, "Unsupported protocol 0x%04x for ipsec offload\n",
                           xs->id.proto);
                return -EINVAL;
        }

        if (xs->xso.flags & XFRM_OFFLOAD_INBOUND) {
                struct rx_sa rsa;

                if (xs->calg) {
                        netdev_err(dev, "Compression offload not supported\n");
                        return -EINVAL;
                }

                /* find the first unused index */
                ret = ixgbe_ipsec_find_empty_idx(ipsec, true);
                if (ret < 0) {
                        netdev_err(dev, "No space for SA in Rx table!\n");
                        return ret;
                }
                sa_idx = (u16)ret;

                memset(&rsa, 0, sizeof(rsa));
                rsa.used = true;
                rsa.xs = xs;

                if (rsa.xs->id.proto & IPPROTO_ESP)
                        rsa.decrypt = xs->ealg || xs->aead;

                /* get the key and salt */
                ret = ixgbe_ipsec_parse_proto_keys(xs, rsa.key, &rsa.salt);
                if (ret) {
                        netdev_err(dev, "Failed to get key data for Rx SA table\n");
                        return ret;
                }

                /* get ip for rx sa table */
                if (xs->props.family == AF_INET6)
                        memcpy(rsa.ipaddr, &xs->id.daddr.a6, 16);
                else
                        memcpy(&rsa.ipaddr[3], &xs->id.daddr.a4, 4);

                /* The HW does not have a 1:1 mapping from keys to IP addrs, so
                 * check for a matching IP addr entry in the table.  If the addr
                 * already exists, use it; else find an unused slot and add the
                 * addr.  If one does not exist and there are no unused table
                 * entries, fail the request.
                 */

                /* Find an existing match or first not used, and stop looking
                 * after we've checked all we know we have.
                 */
                checked = 0;
                match = -1;
                first = -1;
                for (i = 0;
                     i < IXGBE_IPSEC_MAX_RX_IP_COUNT &&
                     (checked < ipsec->num_rx_sa || first < 0);
                     i++) {
                        if (ipsec->ip_tbl[i].used) {
                                if (!memcmp(ipsec->ip_tbl[i].ipaddr,
                                            rsa.ipaddr, sizeof(rsa.ipaddr))) {
                                        match = i;
                                        break;
                                }
                                checked++;
                        } else if (first < 0) {
                                first = i;  /* track the first empty seen */
                        }
                }

                if (ipsec->num_rx_sa == 0)
                        first = 0;

                if (match >= 0) {
                        /* addrs are the same, we should use this one */
                        rsa.iptbl_ind = match;
                        ipsec->ip_tbl[match].ref_cnt++;

                } else if (first >= 0) {
                        /* no matches, but here's an empty slot */
                        rsa.iptbl_ind = first;

                        memcpy(ipsec->ip_tbl[first].ipaddr,
                               rsa.ipaddr, sizeof(rsa.ipaddr));
                        ipsec->ip_tbl[first].ref_cnt = 1;
                        ipsec->ip_tbl[first].used = true;

                        ixgbe_ipsec_set_rx_ip(hw, rsa.iptbl_ind, rsa.ipaddr);

                } else {
                        /* no match and no empty slot */
                        netdev_err(dev, "No space for SA in Rx IP SA table\n");
                        memset(&rsa, 0, sizeof(rsa));
                        return -ENOSPC;
                }

                rsa.mode = IXGBE_RXMOD_VALID;
                if (rsa.xs->id.proto & IPPROTO_ESP)
                        rsa.mode |= IXGBE_RXMOD_PROTO_ESP;
                if (rsa.decrypt)
                        rsa.mode |= IXGBE_RXMOD_DECRYPT;
                if (rsa.xs->props.family == AF_INET6)
                        rsa.mode |= IXGBE_RXMOD_IPV6;

                /* the preparations worked, so save the info */
                memcpy(&ipsec->rx_tbl[sa_idx], &rsa, sizeof(rsa));

                ixgbe_ipsec_set_rx_sa(hw, sa_idx, rsa.xs->id.spi, rsa.key,
                                      rsa.salt, rsa.mode, rsa.iptbl_ind);
                xs->xso.offload_handle = sa_idx + IXGBE_IPSEC_BASE_RX_INDEX;

                ipsec->num_rx_sa++;

                /* hash the new entry for faster search in Rx path */
                hash_add_rcu(ipsec->rx_sa_list, &ipsec->rx_tbl[sa_idx].hlist,
                             rsa.xs->id.spi);
        } else {
                struct tx_sa tsa;

                /* find the first unused index */
                ret = ixgbe_ipsec_find_empty_idx(ipsec, false);
                if (ret < 0) {
                        netdev_err(dev, "No space for SA in Tx table\n");
                        return ret;
                }
                sa_idx = (u16)ret;

                memset(&tsa, 0, sizeof(tsa));
                tsa.used = true;
                tsa.xs = xs;

                if (xs->id.proto & IPPROTO_ESP)
                        tsa.encrypt = xs->ealg || xs->aead;

                ret = ixgbe_ipsec_parse_proto_keys(xs, tsa.key, &tsa.salt);
                if (ret) {
                        netdev_err(dev, "Failed to get key data for Tx SA table\n");
                        memset(&tsa, 0, sizeof(tsa));
                        return ret;
                }

                /* the preparations worked, so save the info */
                memcpy(&ipsec->tx_tbl[sa_idx], &tsa, sizeof(tsa));

                ixgbe_ipsec_set_tx_sa(hw, sa_idx, tsa.key, tsa.salt);

                xs->xso.offload_handle = sa_idx + IXGBE_IPSEC_BASE_TX_INDEX;

                ipsec->num_tx_sa++;
        }

        /* enable the engine if not already warmed up */
        if (!(adapter->flags2 & IXGBE_FLAG2_IPSEC_ENABLED)) {
                ixgbe_ipsec_start_engine(adapter);
                adapter->flags2 |= IXGBE_FLAG2_IPSEC_ENABLED;
        }

        return 0;
}

/**
 * ixgbe_ipsec_del_sa - clear out this specific SA
 * @xs: pointer to transformer state struct
 **/
static void ixgbe_ipsec_del_sa(struct xfrm_state *xs)
{
        struct net_device *dev = xs->xso.dev;
        struct ixgbe_adapter *adapter = netdev_priv(dev);
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct ixgbe_hw *hw = &adapter->hw;
        u32 zerobuf[4] = {0, 0, 0, 0};
        u16 sa_idx;

        if (xs->xso.flags & XFRM_OFFLOAD_INBOUND) {
                struct rx_sa *rsa;
                u8 ipi;

                sa_idx = xs->xso.offload_handle - IXGBE_IPSEC_BASE_RX_INDEX;
                rsa = &ipsec->rx_tbl[sa_idx];

                if (!rsa->used) {
                        netdev_err(dev, "Invalid Rx SA selected sa_idx=%d offload_handle=%lu\n",
                                   sa_idx, xs->xso.offload_handle);
                        return;
                }

                ixgbe_ipsec_set_rx_sa(hw, sa_idx, 0, zerobuf, 0, 0, 0);
                hash_del_rcu(&rsa->hlist);

                /* if the IP table entry is referenced by only this SA,
                 * i.e. ref_cnt is only 1, clear the IP table entry as well
                 */
                ipi = rsa->iptbl_ind;
                if (ipsec->ip_tbl[ipi].ref_cnt > 0) {
                        ipsec->ip_tbl[ipi].ref_cnt--;

                        if (!ipsec->ip_tbl[ipi].ref_cnt) {
                                memset(&ipsec->ip_tbl[ipi], 0,
                                       sizeof(struct rx_ip_sa));
                                ixgbe_ipsec_set_rx_ip(hw, ipi, zerobuf);
                        }
                }

                memset(rsa, 0, sizeof(struct rx_sa));
                ipsec->num_rx_sa--;
        } else {
                sa_idx = xs->xso.offload_handle - IXGBE_IPSEC_BASE_TX_INDEX;

                if (!ipsec->tx_tbl[sa_idx].used) {
                        netdev_err(dev, "Invalid Tx SA selected sa_idx=%d offload_handle=%lu\n",
                                   sa_idx, xs->xso.offload_handle);
                        return;
                }

                ixgbe_ipsec_set_tx_sa(hw, sa_idx, zerobuf, 0);
                memset(&ipsec->tx_tbl[sa_idx], 0, sizeof(struct tx_sa));
                ipsec->num_tx_sa--;
        }

        /* if there are no SAs left, stop the engine to save energy */
        if (ipsec->num_rx_sa == 0 && ipsec->num_tx_sa == 0) {
                adapter->flags2 &= ~IXGBE_FLAG2_IPSEC_ENABLED;
                ixgbe_ipsec_stop_engine(adapter);
        }
}

/**
 * ixgbe_ipsec_offload_ok - can this packet use the xfrm hw offload
 * @skb: current data packet
 * @xs: pointer to transformer state struct
 **/
static bool ixgbe_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
{
        if (xs->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;
}

static const struct xfrmdev_ops ixgbe_xfrmdev_ops = {
        .xdo_dev_state_add = ixgbe_ipsec_add_sa,
        .xdo_dev_state_delete = ixgbe_ipsec_del_sa,
        .xdo_dev_offload_ok = ixgbe_ipsec_offload_ok,
};

/**
 * ixgbe_ipsec_tx - setup Tx flags for ipsec offload
 * @tx_ring: outgoing context
 * @first: current data packet
 * @itd: ipsec Tx data for later use in building context descriptor
 **/
int ixgbe_ipsec_tx(struct ixgbe_ring *tx_ring,
                   struct ixgbe_tx_buffer *first,
                   struct ixgbe_ipsec_tx_data *itd)
{
        struct ixgbe_adapter *adapter = netdev_priv(tx_ring->netdev);
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct xfrm_state *xs;
        struct tx_sa *tsa;

        if (unlikely(!first->skb->sp->len)) {
                netdev_err(tx_ring->netdev, "%s: no xfrm state len = %d\n",
                           __func__, first->skb->sp->len);
                return 0;
        }

        xs = xfrm_input_state(first->skb);
        if (unlikely(!xs)) {
                netdev_err(tx_ring->netdev, "%s: no xfrm_input_state() xs = %p\n",
                           __func__, xs);
                return 0;
        }

        itd->sa_idx = xs->xso.offload_handle - IXGBE_IPSEC_BASE_TX_INDEX;
        if (unlikely(itd->sa_idx > IXGBE_IPSEC_MAX_SA_COUNT)) {
                netdev_err(tx_ring->netdev, "%s: bad sa_idx=%d handle=%lu\n",
                           __func__, itd->sa_idx, xs->xso.offload_handle);
                return 0;
        }

        tsa = &ipsec->tx_tbl[itd->sa_idx];
        if (unlikely(!tsa->used)) {
                netdev_err(tx_ring->netdev, "%s: unused sa_idx=%d\n",
                           __func__, itd->sa_idx);
                return 0;
        }

        first->tx_flags |= IXGBE_TX_FLAGS_IPSEC | IXGBE_TX_FLAGS_CC;

        if (xs->id.proto == IPPROTO_ESP) {

                itd->flags |= IXGBE_ADVTXD_TUCMD_IPSEC_TYPE_ESP |
                              IXGBE_ADVTXD_TUCMD_L4T_TCP;
                if (first->protocol == htons(ETH_P_IP))
                        itd->flags |= IXGBE_ADVTXD_TUCMD_IPV4;

                /* The actual trailer length is authlen (16 bytes) plus
                 * 2 bytes for the proto and the padlen values, plus
                 * padlen bytes of padding.  This ends up not the same
                 * as the static value found in xs->props.trailer_len (21).
                 *
                 * ... but if we're doing GSO, don't bother as the stack
                 * doesn't add a trailer for those.
                 */
                if (!skb_is_gso(first->skb)) {
                        /* The "correct" way to get the auth length would be
                         * to use
                         *    authlen = crypto_aead_authsize(xs->data);
                         * but since we know we only have one size to worry
                         * about * we can let the compiler use the constant
                         * and save us a few CPU cycles.
                         */
                        const int authlen = IXGBE_IPSEC_AUTH_BITS / 8;
                        struct sk_buff *skb = first->skb;
                        u8 padlen;
                        int ret;

                        ret = skb_copy_bits(skb, skb->len - (authlen + 2),
                                            &padlen, 1);
                        if (unlikely(ret))
                                return 0;
                        itd->trailer_len = authlen + 2 + padlen;
                }
        }
        if (tsa->encrypt)
                itd->flags |= IXGBE_ADVTXD_TUCMD_IPSEC_ENCRYPT_EN;

        return 1;
}

/**
 * ixgbe_ipsec_rx - decode ipsec bits from Rx descriptor
 * @rx_ring: receiving ring
 * @rx_desc: receive data descriptor
 * @skb: current data packet
 *
 * Determine if there was an ipsec encapsulation noticed, and if so set up
 * the resulting status for later in the receive stack.
 **/
void ixgbe_ipsec_rx(struct ixgbe_ring *rx_ring,
                    union ixgbe_adv_rx_desc *rx_desc,
                    struct sk_buff *skb)
{
        struct ixgbe_adapter *adapter = netdev_priv(rx_ring->netdev);
        __le16 pkt_info = rx_desc->wb.lower.lo_dword.hs_rss.pkt_info;
        __le16 ipsec_pkt_types = cpu_to_le16(IXGBE_RXDADV_PKTTYPE_IPSEC_AH |
                                             IXGBE_RXDADV_PKTTYPE_IPSEC_ESP);
        struct ixgbe_ipsec *ipsec = adapter->ipsec;
        struct xfrm_offload *xo = NULL;
        struct xfrm_state *xs = NULL;
        struct ipv6hdr *ip6 = NULL;
        struct iphdr *ip4 = NULL;
        void *daddr;
        __be32 spi;
        u8 *c_hdr;
        u8 proto;

        /* Find the ip and crypto headers in the data.
         * We can assume no vlan header in the way, b/c the
         * hw won't recognize the IPsec packet and anyway the
         * currently vlan device doesn't support xfrm offload.
         */
        if (pkt_info & cpu_to_le16(IXGBE_RXDADV_PKTTYPE_IPV4)) {
                ip4 = (struct iphdr *)(skb->data + ETH_HLEN);
                daddr = &ip4->daddr;
                c_hdr = (u8 *)ip4 + ip4->ihl * 4;
        } else if (pkt_info & cpu_to_le16(IXGBE_RXDADV_PKTTYPE_IPV6)) {
                ip6 = (struct ipv6hdr *)(skb->data + ETH_HLEN);
                daddr = &ip6->daddr;
                c_hdr = (u8 *)ip6 + sizeof(struct ipv6hdr);
        } else {
                return;
        }

        switch (pkt_info & ipsec_pkt_types) {
        case cpu_to_le16(IXGBE_RXDADV_PKTTYPE_IPSEC_AH):
                spi = ((struct ip_auth_hdr *)c_hdr)->spi;
                proto = IPPROTO_AH;
                break;
        case cpu_to_le16(IXGBE_RXDADV_PKTTYPE_IPSEC_ESP):
                spi = ((struct ip_esp_hdr *)c_hdr)->spi;
                proto = IPPROTO_ESP;
                break;
        default:
                return;
        }

        xs = ixgbe_ipsec_find_rx_state(ipsec, daddr, proto, spi, !!ip4);
        if (unlikely(!xs))
                return;

        skb->sp = secpath_dup(skb->sp);
        if (unlikely(!skb->sp))
                return;

        skb->sp->xvec[skb->sp->len++] = xs;
        skb->sp->olen++;
        xo = xfrm_offload(skb);
        xo->flags = CRYPTO_DONE;
        xo->status = CRYPTO_SUCCESS;

        adapter->rx_ipsec++;
}

/**
 * ixgbe_init_ipsec_offload - initialize security registers for IPSec operation
 * @adapter: board private structure
 **/
void ixgbe_init_ipsec_offload(struct ixgbe_adapter *adapter)
{
        struct ixgbe_ipsec *ipsec;
        size_t size;

        if (adapter->hw.mac.type == ixgbe_mac_82598EB)
                return;

        ipsec = kzalloc(sizeof(*ipsec), GFP_KERNEL);
        if (!ipsec)
                goto err1;
        hash_init(ipsec->rx_sa_list);

        size = sizeof(struct rx_sa) * IXGBE_IPSEC_MAX_SA_COUNT;
        ipsec->rx_tbl = kzalloc(size, GFP_KERNEL);
        if (!ipsec->rx_tbl)
                goto err2;

        size = sizeof(struct tx_sa) * IXGBE_IPSEC_MAX_SA_COUNT;
        ipsec->tx_tbl = kzalloc(size, GFP_KERNEL);
        if (!ipsec->tx_tbl)
                goto err2;

        size = sizeof(struct rx_ip_sa) * IXGBE_IPSEC_MAX_RX_IP_COUNT;
        ipsec->ip_tbl = kzalloc(size, GFP_KERNEL);
        if (!ipsec->ip_tbl)
                goto err2;

        ipsec->num_rx_sa = 0;
        ipsec->num_tx_sa = 0;

        adapter->ipsec = ipsec;
        ixgbe_ipsec_stop_engine(adapter);
        ixgbe_ipsec_clear_hw_tables(adapter);

        adapter->netdev->xfrmdev_ops = &ixgbe_xfrmdev_ops;

#define IXGBE_ESP_FEATURES      (NETIF_F_HW_ESP | \
                                 NETIF_F_HW_ESP_TX_CSUM | \
                                 NETIF_F_GSO_ESP)

        adapter->netdev->features |= IXGBE_ESP_FEATURES;
        adapter->netdev->hw_enc_features |= IXGBE_ESP_FEATURES;

        return;

err2:
        kfree(ipsec->ip_tbl);
        kfree(ipsec->rx_tbl);
        kfree(ipsec->tx_tbl);
        kfree(ipsec);
err1:
        netdev_err(adapter->netdev, "Unable to allocate memory for SA tables");
}

/**
 * ixgbe_stop_ipsec_offload - tear down the ipsec offload
 * @adapter: board private structure
 **/
void ixgbe_stop_ipsec_offload(struct ixgbe_adapter *adapter)
{
        struct ixgbe_ipsec *ipsec = adapter->ipsec;

        adapter->ipsec = NULL;
        if (ipsec) {
                kfree(ipsec->ip_tbl);
                kfree(ipsec->rx_tbl);
                kfree(ipsec->tx_tbl);
                kfree(ipsec);
        }
}