Message-ID: <CAKgT0UcCgeOfebWdVB3Z5NNaVXXd917JUMRbignojMf8TZw2ow@mail.gmail.com>
Date:   Tue, 5 Dec 2017 09:26:04 -0800
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Shannon Nelson <shannon.nelson@...cle.com>
Cc:     intel-wired-lan <intel-wired-lan@...ts.osuosl.org>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Sowmini Varadhan <sowmini.varadhan@...cle.com>,
        Netdev <netdev@...r.kernel.org>
Subject: Re: [Intel-wired-lan] [next-queue 05/10] ixgbe: implement ipsec add
 and remove of offloaded SA

On Mon, Dec 4, 2017 at 9:35 PM, Shannon Nelson
<shannon.nelson@...cle.com> wrote:
> Add the functions for setting up and removing offloaded SAs (Security
> Associations) with the x540 hardware.  We set up the callback structure
> but we don't yet set the hardware feature bit to be sure the XFRM service
> won't actually try to use us for an offload yet.
>
> The software tables are made up to mimic the hardware tables to make it
> easier to track what's in the hardware, and the SA table index is used
> for the XFRM offload handle.  However, there is a hashing field in the
> Rx SA tracking that will be used to facilitate faster table searches in
> the Rx fast path.
>
> Signed-off-by: Shannon Nelson <shannon.nelson@...cle.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c | 377 +++++++++++++++++++++++++
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c  |   6 +
>  2 files changed, 383 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
> index 38a1a16..7b01d92 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c
> @@ -26,6 +26,8 @@
>   ******************************************************************************/
>
>  #include "ixgbe.h"
> +#include <net/xfrm.h>
> +#include <crypto/aead.h>
>
>  /**
>   * ixgbe_ipsec_set_tx_sa - set the Tx SA registers
> @@ -128,6 +130,7 @@ static void ixgbe_ipsec_set_rx_ip(struct ixgbe_hw *hw, u16 idx, u32 addr[])
>   **/
>  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;
> @@ -139,9 +142,11 @@ void ixgbe_ipsec_clear_hw_tables(struct ixgbe_adapter *adapter)
>         /* scrub the tables */
>         for (idx = 0; idx < IXGBE_IPSEC_MAX_SA_COUNT; idx++)
>                 ixgbe_ipsec_set_tx_sa(hw, idx, buf, 0);
> +       ipsec->num_tx_sa = 0;
>
>         for (idx = 0; idx < IXGBE_IPSEC_MAX_SA_COUNT; idx++)
>                 ixgbe_ipsec_set_rx_sa(hw, idx, 0, buf, 0, 0, 0);
> +       ipsec->num_rx_sa = 0;
>
>         for (idx = 0; idx < IXGBE_IPSEC_MAX_RX_IP_COUNT; idx++)
>                 ixgbe_ipsec_set_rx_ip(hw, idx, buf);
> @@ -287,11 +292,383 @@ static void ixgbe_ipsec_start_engine(struct ixgbe_adapter *adapter)
>  }
>
>  /**
> + * 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_rx_sa == IXGBE_IPSEC_MAX_SA_COUNT)
> +                       return -ENOSPC;

Should this bi num_tx_sa?

> +
> +               /* 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_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;
> +       char *aes_gcm_name = "rfc4106(gcm(aes))";

aes_gcm_name should probably be a static const char array instead of a pointer.

> +       int key_len;
> +
> +       if (xs->aead) {
> +               key_data = &xs->aead->alg_key[0];
> +               key_len = xs->aead->alg_key_len;
> +               alg_name = xs->aead->alg_name;
> +       } else {
> +               netdev_err(dev, "Unsupported IPsec algorithm\n");
> +               return -EINVAL;
> +       }
> +
> +       if (strcmp(alg_name, aes_gcm_name)) {
> +               netdev_err(dev, "Unsupported IPsec algorithm - please use %s\n",
> +                          aes_gcm_name);
> +               return -EINVAL;
> +       }
> +
> +       /* 160 accounts for 16 byte key and 4 byte salt */
> +       if (key_len == 128) {
> +               netdev_info(dev, "IPsec hw offload parameters missing 32 bit salt value\n");
> +       } else if (key_len != 160) {
> +               netdev_err(dev, "IPsec hw offload only supports keys up to 128 bits with a 32 bit salt\n");
> +               return -EINVAL;
> +       }
> +
> +       /* The key bytes come down in a bigendian array of bytes, and
> +        * salt is always the last 4 bytes of the key array.
> +        * We don't need to do any byteswapping.
> +        */
> +       memcpy(mykey, key_data, 16);
> +       if (key_len == 160)
> +               *mysalt = ((u32 *)key_data)[4];
> +       else
> +               *mysalt = 0;

You could combine these key_len checks into a single if/else set.
Basically just do something like the following:

/* 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;
}

 /* The key bytes come down in a bigendian array of bytes, and
  * salt is always the last 4 bytes of the key array.
  * We don't need to do any byteswapping.
  */
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->xso.flags & XFRM_OFFLOAD_IPV6)
> +                       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->xso.flags & XFRM_OFFLOAD_IPV6)
> +                       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);
> +       }
> +}
> +
> +static const struct xfrmdev_ops ixgbe_xfrmdev_ops = {
> +       .xdo_dev_state_add = ixgbe_ipsec_add_sa,
> +       .xdo_dev_state_delete = ixgbe_ipsec_del_sa,
> +};
> +
> +/**
>   * 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;
> +
> +       ipsec = kzalloc(sizeof(*ipsec), GFP_KERNEL);
> +       if (!ipsec)
> +               goto err;

I would say just add another label to skip over the if statement you
added below.

> +       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 err;
> +
> +       size = sizeof(struct tx_sa) * IXGBE_IPSEC_MAX_SA_COUNT;
> +       ipsec->tx_tbl = kzalloc(size, GFP_KERNEL);
> +       if (!ipsec->tx_tbl)
> +               goto err;
> +
> +       size = sizeof(struct rx_ip_sa) * IXGBE_IPSEC_MAX_RX_IP_COUNT;
> +       ipsec->ip_tbl = kzalloc(size, GFP_KERNEL);
> +       if (!ipsec->ip_tbl)
> +               goto err;

Do all these tables need to be allocated separately? I'm just
wondering if we can get away with doing something like what we did
with the ixgbe_q_vector structure where you just allocate this as one
physical block of memory and just split it up into multiple chunks
with a separate pointer to each chunk. Doing that would cut down on
the exception handling needed since it would be a single allocation
failure you would have to deal with.

> +       ipsec->num_rx_sa = 0;
> +       ipsec->num_tx_sa = 0;
> +
> +       adapter->ipsec = ipsec;
>         ixgbe_ipsec_clear_hw_tables(adapter);
>         ixgbe_ipsec_stop_engine(adapter);
> +
> +       return;
> +err:
> +       if (ipsec) {
> +               kfree(ipsec->ip_tbl);
> +               kfree(ipsec->rx_tbl);
> +               kfree(ipsec->tx_tbl);
> +               kfree(adapter->ipsec);
> +       }
> +       netdev_err(adapter->netdev, "Unable to allocate memory for SA tables");
>  }
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 51fb3cf..01fd89b 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -10542,6 +10542,12 @@ static void ixgbe_remove(struct pci_dev *pdev)
>         set_bit(__IXGBE_REMOVING, &adapter->state);
>         cancel_work_sync(&adapter->service_task);
>
> +#ifdef CONFIG_XFRM
> +       kfree(adapter->ipsec->ip_tbl);
> +       kfree(adapter->ipsec->rx_tbl);
> +       kfree(adapter->ipsec->tx_tbl);
> +       kfree(adapter->ipsec);
> +#endif /* CONFIG_XFRM */

It might be useful if you were to move this into a function of its
own. Also you should probably check for adapter->ipsec first,
otherwise you are going to cause NULL pointer dereference any time
adapter->ipsec isn't defined. because you are dereferencing it when
you go to free each of those tables.

>
>  #ifdef CONFIG_IXGBE_DCA
>         if (adapter->flags & IXGBE_FLAG_DCA_ENABLED) {
> --
> 2.7.4
>
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan@...osl.org
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