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Date: Fri, 22 Jun 2018 21:07:08 -0700
From: Jakub Kicinski <jakub.kicinski@...ronome.com>
To: Shannon Nelson <shannon.nelson@...cle.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org,
anders.roxell@...aro.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next 3/4] netdevsim: add ipsec offload testing
On Fri, 22 Jun 2018 17:31:37 -0700, Shannon Nelson wrote:
> Implement the IPsec/XFRM offload API for testing.
>
> Signed-off-by: Shannon Nelson <shannon.nelson@...cle.com>
Thanks for the patch! Just a number of stylistic nit picks.
> diff --git a/drivers/net/netdevsim/ipsec.c b/drivers/net/netdevsim/ipsec.c
> new file mode 100644
> index 0000000..ad64266
> --- /dev/null
> +++ b/drivers/net/netdevsim/ipsec.c
> @@ -0,0 +1,345 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright(c) 2018 Oracle and/or its affiliates. All rights reserved. */
> +
> +#include <net/xfrm.h>
> +#include <crypto/aead.h>
> +#include <linux/debugfs.h>
> +#include "netdevsim.h"
Other files in the driver sort headers alphabetically and put an empty
line between global and local headers.
> +#define NSIM_IPSEC_AUTH_BITS 128
> +
> +/**
> + * nsim_ipsec_dbg_read - read for ipsec data
> + * @filp: the opened file
> + * @buffer: where to write the data for the user to read
> + * @count: the size of the user's buffer
> + * @ppos: file position offset
> + **/
> +static ssize_t nsim_dbg_netdev_ops_read(struct file *filp,
Doesn't match the kdoc. Please run
./scripts/kernel-doc -none $file
if you want kdoc. Although IMHO you may as well drop the kdoc, your
code is quite self explanatory and local.
> + char __user *buffer,
> + size_t count, loff_t *ppos)
> +{
> + struct netdevsim *ns = filp->private_data;
> + struct nsim_ipsec *ipsec = &ns->ipsec;
> + size_t bufsize;
> + char *buf, *p;
> + int len;
> + int i;
> +
> + /* don't allow partial reads */
> + if (*ppos != 0)
> + return 0;
> +
> + /* the buffer needed is
> + * (num SAs * 3 lines each * ~60 bytes per line) + one more line
> + */
> + bufsize = (ipsec->count * 4 * 60) + 60;
> + buf = kzalloc(bufsize, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + p = buf;
> + p += snprintf(p, bufsize - (p - buf),
> + "SA count=%u tx=%u\n",
> + ipsec->count, ipsec->tx);
> +
> + for (i = 0; i < NSIM_IPSEC_MAX_SA_COUNT; i++) {
> + struct nsim_sa *sap = &ipsec->sa[i];
> +
> + if (!sap->used)
> + continue;
> +
> + p += snprintf(p, bufsize - (p - buf),
> + "sa[%i] %cx ipaddr=0x%08x %08x %08x %08x\n",
> + i, (sap->rx ? 'r' : 't'), sap->ipaddr[0],
> + sap->ipaddr[1], sap->ipaddr[2], sap->ipaddr[3]);
> + p += snprintf(p, bufsize - (p - buf),
> + "sa[%i] spi=0x%08x proto=0x%x salt=0x%08x crypt=%d\n",
> + i, be32_to_cpu(sap->xs->id.spi),
> + sap->xs->id.proto, sap->salt, sap->crypt);
> + p += snprintf(p, bufsize - (p - buf),
> + "sa[%i] key=0x%08x %08x %08x %08x\n",
> + i, sap->key[0], sap->key[1],
> + sap->key[2], sap->key[3]);
> + }
> +
> + len = simple_read_from_buffer(buffer, count, ppos, buf, p - buf);
Why not seq_file for this?
> + kfree(buf);
> + return len;
> +}
> +
> +static const struct file_operations ipsec_dbg_fops = {
> + .owner = THIS_MODULE,
> + .open = simple_open,
> + .read = nsim_dbg_netdev_ops_read,
> +};
> +
> +/**
> + * nsim_ipsec_find_empty_idx - find the first unused security parameter index
> + * @ipsec: pointer to ipsec struct
> + **/
> +static int nsim_ipsec_find_empty_idx(struct nsim_ipsec *ipsec)
> +{
> + u32 i;
> +
> + if (ipsec->count == NSIM_IPSEC_MAX_SA_COUNT)
> + return -ENOSPC;
> +
> + /* search sa table */
> + for (i = 0; i < NSIM_IPSEC_MAX_SA_COUNT; i++) {
> + if (!ipsec->sa[i].used)
> + return i;
> + }
> +
> + return -ENOSPC;
FWIW I personally find bitmaps and find_first_zero_bit() etc. nice and
concise for a small ID allocator, but no objection to open coding.
> +}
> +
> +/**
> + * nsim_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.
82599 is a fine chip, it's not netdevsim tho? ;)
> + **/
> +static int nsim_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;
reverse xmas tree please
> +
> + if (!xs->aead) {
> + netdev_err(dev, "Unsupported IPsec algorithm\n");
> + return -EINVAL;
> + }
> +
> + if (xs->aead->alg_icv_len != NSIM_IPSEC_AUTH_BITS) {
> + netdev_err(dev, "IPsec offload requires %d bit authentication\n",
> + NSIM_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.
Why the mention of bigendian? 82599 needs big endian? -.^
> + * 160 accounts for 16 byte key and 4 byte salt
> + */
> + if (key_len > 128) {
s/128/NSIM_IPSEC_AUTH_BITS/ ?
> + *mysalt = ((u32 *)key_data)[4];
Is alignment guaranteed? There are the unaligned helpers if you need
them..
> + } else if (key_len == 128) {
> + *mysalt = 0;
> + } else {
> + netdev_err(dev, "IPsec hw offload only supports 128 bit keys with optional 32 bit salt\n");
> + return -EINVAL;
> + }
> + memcpy(mykey, key_data, 16);
> +
> + return 0;
> +}
> +
> +/**
> + * nsim_ipsec_add_sa - program device with a security association
> + * @xs: pointer to transformer state struct
> + **/
> +static int nsim_ipsec_add_sa(struct xfrm_state *xs)
> +{
> + struct net_device *dev = xs->xso.dev;
> + struct netdevsim *ns = netdev_priv(dev);
> + struct nsim_ipsec *ipsec = &ns->ipsec;
xmas tree again (initialize out of line if you have to)
> + struct nsim_sa sa;
> + u16 sa_idx;
> + int ret;
> +
> + 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->calg) {
> + netdev_err(dev, "Compression offload not supported\n");
> + return -EINVAL;
> + }
> +
> + /* find the first unused index */
> + ret = nsim_ipsec_find_empty_idx(ipsec);
> + if (ret < 0) {
> + netdev_err(dev, "No space for SA in Rx table!\n");
> + return ret;
> + }
> + sa_idx = (u16)ret;
> +
> + memset(&sa, 0, sizeof(sa));
> + sa.used = true;
> + sa.xs = xs;
> +
> + if (sa.xs->id.proto & IPPROTO_ESP)
> + sa.crypt = xs->ealg || xs->aead;
> +
> + /* get the key and salt */
> + ret = nsim_ipsec_parse_proto_keys(xs, sa.key, &sa.salt);
> + if (ret) {
> + netdev_err(dev, "Failed to get key data for SA table\n");
> + return ret;
> + }
> +
> + if (xs->xso.flags & XFRM_OFFLOAD_INBOUND) {
> + sa.rx = true;
> +
> + if (xs->props.family == AF_INET6)
> + memcpy(sa.ipaddr, &xs->id.daddr.a6, 16);
> + else
> + memcpy(&sa.ipaddr[3], &xs->id.daddr.a4, 4);
> + }
> +
> + /* the preparations worked, so save the info */
> + memcpy(&ipsec->sa[sa_idx], &sa, sizeof(sa));
> +
> + /* the XFRM stack doesn't like offload_handle == 0,
> + * so add a bitflag in case our array index is 0
> + */
> + xs->xso.offload_handle = sa_idx | NSIM_IPSEC_VALID;
> + ipsec->count++;
> +
> + return 0;
> +}
> +
> +/**
> + * nsim_ipsec_del_sa - clear out this specific SA
> + * @xs: pointer to transformer state struct
> + **/
> +static void nsim_ipsec_del_sa(struct xfrm_state *xs)
> +{
> + struct net_device *dev = xs->xso.dev;
> + struct netdevsim *ns = netdev_priv(dev);
> + struct nsim_ipsec *ipsec = &ns->ipsec;
> + u16 sa_idx;
> +
> + sa_idx = xs->xso.offload_handle & ~NSIM_IPSEC_VALID;
> + if (!ipsec->sa[sa_idx].used) {
> + netdev_err(dev, "Invalid SA for delete sa_idx=%d\n", sa_idx);
> + return;
> + }
> +
> + memset(&ipsec->sa[sa_idx], 0, sizeof(struct nsim_sa));
> + ipsec->count--;
> +}
> +
> +/**
> + * nsim_ipsec_offload_ok - can this packet use the xfrm hw offload
> + * @skb: current data packet
> + * @xs: pointer to transformer state struct
> + **/
> +static bool nsim_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
> +{
> + struct net_device *dev = xs->xso.dev;
> + struct netdevsim *ns = netdev_priv(dev);
> + struct nsim_ipsec *ipsec = &ns->ipsec;
> +
> + ipsec->ok++;
> +
> + return true;
> +}
> +
> +static const struct xfrmdev_ops nsim_xfrmdev_ops = {
> + .xdo_dev_state_add = nsim_ipsec_add_sa,
> + .xdo_dev_state_delete = nsim_ipsec_del_sa,
> + .xdo_dev_offload_ok = nsim_ipsec_offload_ok,
Please align the initializers by adding tabs before '='.
> +};
> +
> +/**
> + * nsim_ipsec_tx - check Tx packet for ipsec offload
> + * @ns: pointer to ns structure
> + * @skb: current data packet
> + **/
> +int nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
> +{
> + struct nsim_ipsec *ipsec = &ns->ipsec;
> + struct xfrm_state *xs;
> + struct nsim_sa *tsa;
> + u32 sa_idx;
> +
> + /* do we even need to check this packet? */
> + if (!skb->sp)
> + return 1;
> +
> + if (unlikely(!skb->sp->len)) {
> + netdev_err(ns->netdev, "%s: no xfrm state len = %d\n",
> + __func__, skb->sp->len);
Hmm.. __func__ started appearing in errors? Perhaps either always or
never add it?
Also, I know this is not a real device, but please always use rate
limited print functions on the data path.
> + return 0;
> + }
> +
> + xs = xfrm_input_state(skb);
> + if (unlikely(!xs)) {
> + netdev_err(ns->netdev, "%s: no xfrm_input_state() xs = %p\n",
> + __func__, xs);
> + return 0;
> + }
> +
> + sa_idx = xs->xso.offload_handle & ~NSIM_IPSEC_VALID;
> + if (unlikely(sa_idx > NSIM_IPSEC_MAX_SA_COUNT)) {
> + netdev_err(ns->netdev, "%s: bad sa_idx=%d max=%d\n",
> + __func__, sa_idx, NSIM_IPSEC_MAX_SA_COUNT);
> + return 0;
> + }
> +
> + tsa = &ipsec->sa[sa_idx];
> + if (unlikely(!tsa->used)) {
> + netdev_err(ns->netdev, "%s: unused sa_idx=%d\n",
> + __func__, sa_idx);
> + return 0;
> + }
> +
> + if (xs->id.proto != IPPROTO_ESP && xs->id.proto != IPPROTO_AH) {
> + netdev_err(ns->netdev, "%s: unexpected proto=%d\n",
> + __func__, xs->id.proto);
> + return 0;
> + }
> +
> + ipsec->tx++;
> +
> + return 1;
> +}
Looks like the function should return bool?
> +
> +/**
> + * nsim_ipsec_init - initialize security registers for IPSec operation
> + * @ns: board private structure
"board"? Yes, the kdoc may be best removed ;)
> + **/
> +void nsim_ipsec_init(struct netdevsim *ns)
> +{
> + ns->netdev->xfrmdev_ops = &nsim_xfrmdev_ops;
> +
> +#define NSIM_ESP_FEATURES (NETIF_F_HW_ESP | \
> + NETIF_F_HW_ESP_TX_CSUM | \
> + NETIF_F_GSO_ESP)
> +
> + ns->netdev->features |= NSIM_ESP_FEATURES;
> + ns->netdev->hw_enc_features |= NSIM_ESP_FEATURES;
> +
> + ns->ipsec.pfile = debugfs_create_file("ipsec", 0400, ns->ddir, ns,
> + &ipsec_dbg_fops);
> +}
> +
> +void nsim_ipsec_teardown(struct netdevsim *ns)
> +{
> + struct nsim_ipsec *ipsec = &ns->ipsec;
> +
> + if (ipsec->count)
> + netdev_err(ns->netdev, "%s: tearing down IPsec offload with %d SAs left\n",
> + __func__, ipsec->count);
> + debugfs_remove_recursive(ipsec->pfile);
> +}
> diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
> index ec68f38..6ce8604d 100644
> --- a/drivers/net/netdevsim/netdev.c
> +++ b/drivers/net/netdevsim/netdev.c
> @@ -171,6 +171,8 @@ static int nsim_init(struct net_device *dev)
> if (err)
> goto err_unreg_dev;
>
> + nsim_ipsec_init(ns);
> +
> return 0;
>
> err_unreg_dev:
> @@ -186,6 +188,7 @@ static void nsim_uninit(struct net_device *dev)
> {
> struct netdevsim *ns = netdev_priv(dev);
>
> + nsim_ipsec_teardown(ns);
> nsim_devlink_teardown(ns);
> debugfs_remove_recursive(ns->ddir);
> nsim_bpf_uninit(ns);
> @@ -203,11 +206,15 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
> {
> struct netdevsim *ns = netdev_priv(dev);
>
> + if (!nsim_ipsec_tx(ns, skb))
> + goto out;
> +
> u64_stats_update_begin(&ns->syncp);
> ns->tx_packets++;
> ns->tx_bytes += skb->len;
> u64_stats_update_end(&ns->syncp);
>
> +out:
> dev_kfree_skb(skb);
>
> return NETDEV_TX_OK;
> diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
> index 3a8581a..1708dee 100644
> --- a/drivers/net/netdevsim/netdevsim.h
> +++ b/drivers/net/netdevsim/netdevsim.h
> @@ -29,6 +29,29 @@ struct bpf_prog;
> struct dentry;
> struct nsim_vf_config;
>
> +#if IS_ENABLED(CONFIG_XFRM_OFFLOAD)
> +#define NSIM_IPSEC_MAX_SA_COUNT 33
33 caught my eye - out of curiosity is it 2^5 + 1 to catch some type of
bug or failure mode?
> +#define NSIM_IPSEC_VALID BIT(31)
> +
> +struct nsim_sa {
> + struct xfrm_state *xs;
> + __be32 ipaddr[4];
> + u32 key[4];
> + u32 salt;
> + bool used;
> + bool crypt;
> + bool rx;
> +};
> +
> +struct nsim_ipsec {
> + struct nsim_sa sa[NSIM_IPSEC_MAX_SA_COUNT];
> + struct dentry *pfile;
> + u32 count;
> + u32 tx;
> + u32 ok;
> +};
> +#endif
No need to wrap struct definitions in #if/#endif.
> struct netdevsim {
> struct net_device *netdev;
>
> @@ -67,6 +90,9 @@ struct netdevsim {
> #if IS_ENABLED(CONFIG_NET_DEVLINK)
> struct devlink *devlink;
> #endif
> +#if IS_ENABLED(CONFIG_XFRM_OFFLOAD)
> + struct nsim_ipsec ipsec;
> +#endif
> };
>
> extern struct dentry *nsim_ddir;
> @@ -147,6 +173,17 @@ static inline void nsim_devlink_exit(void)
> }
> #endif
>
> +#if IS_ENABLED(CONFIG_XFRM_OFFLOAD)
> +void nsim_ipsec_init(struct netdevsim *ns);
> +void nsim_ipsec_teardown(struct netdevsim *ns);
> +int nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb);
> +#else
> +static inline void nsim_ipsec_init(struct netdevsim *ns) {};
> +static inline void nsim_ipsec_teardown(struct netdevsim *ns) {};
> +static inline int nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
> + { return 1; };
Please use the same formatting for static inlines as the rest of the
file. The ';' are also unnecessary.
Other than those formatting nit picks looks good to me :)
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