Subject: Re: [PATCH 1/2] xfrm: add SA information to the offloaded packet

From: Leon Romanovsky <[email-masked]>
Date: Tue, 5 Nov 2024 09:32:48 +0200

On Mon, Nov 04, 2024 at 03:32:51PM -0800, Feng Wang wrote:
> From: wangfe <[email-masked]>
> 
> In packet offload mode, append Security Association (SA) information
> to each packet, replicating the crypto offload implementation.
> The XFRM_XMIT flag is set to enable packet to be returned immediately
> from the validate_xmit_xfrm function, thus aligning with the existing
> code path for packet offload mode.
> 
> This SA info helps HW offload match packets to their correct security
> policies. The XFRM interface ID is included, which is used in setups
> with multiple XFRM interfaces where source/destination addresses alone
> can't pinpoint the right policy.
> 
> Enable packet offload mode on netdevsim and add code to check the XFRM
> interface ID.
> 
> Signed-off-by: wangfe <[email-masked]>

Something wrong with your git setup, lore shows only one patch.
https://lore.kernel.org/all/[email-masked]/

> ---
> v3: https://lore.kernel.org/all/[email-masked]/
>   - Add XFRM interface ID checking on netdevsim in the packet offload
>     mode.
> v2:
>   - Add why HW offload requires the SA info to the commit message
> v1: https://lore.kernel.org/all/[email-masked]/
> ---
> ---
>  drivers/net/netdevsim/ipsec.c     | 24 +++++++++++++++++++++++-
>  drivers/net/netdevsim/netdevsim.h |  1 +
>  net/xfrm/xfrm_output.c            | 21 +++++++++++++++++++++
>  3 files changed, 45 insertions(+), 1 deletion(-)

Don't you need to update current drivers who support packet offload with
if(x->if_id) check in their SA/policy validator to return an error to
the user? They don't support that flow.

> 
> diff --git a/drivers/net/netdevsim/ipsec.c b/drivers/net/netdevsim/ipsec.c
> index f0d58092e7e9..1ce7447dd269 100644
> --- a/drivers/net/netdevsim/ipsec.c
> +++ b/drivers/net/netdevsim/ipsec.c
> @@ -149,7 +149,8 @@ static int nsim_ipsec_add_sa(struct xfrm_state *xs,
>  		return -EINVAL;
>  	}
>  
> -	if (xs->xso.type != XFRM_DEV_OFFLOAD_CRYPTO) {
> +	if (xs->xso.type != XFRM_DEV_OFFLOAD_CRYPTO &&
> +	    xs->xso.type != XFRM_DEV_OFFLOAD_PACKET) {
>  		NL_SET_ERR_MSG_MOD(extack, "Unsupported ipsec offload type");
>  		return -EINVAL;
>  	}
> @@ -165,6 +166,7 @@ static int nsim_ipsec_add_sa(struct xfrm_state *xs,
>  	memset(&sa, 0, sizeof(sa));
>  	sa.used = true;
>  	sa.xs = xs;
> +	sa.if_id = xs->if_id;
>  
>  	if (sa.xs->id.proto & IPPROTO_ESP)
>  		sa.crypt = xs->ealg || xs->aead;
> @@ -224,10 +226,24 @@ static bool nsim_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
>  	return true;
>  }
>  
> +static int nsim_ipsec_add_policy(struct xfrm_policy *policy,
> +				 struct netlink_ext_ack *extack)
> +{
> +	return 0;
> +}
> +
> +static void nsim_ipsec_del_policy(struct xfrm_policy *policy)
> +{
> +}
> +
>  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,
> +
> +	.xdo_dev_policy_add     = nsim_ipsec_add_policy,
> +	.xdo_dev_policy_delete  = nsim_ipsec_del_policy,
> +
>  };
>  
>  bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
> @@ -272,6 +288,12 @@ bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
>  		return false;
>  	}
>  
> +	if (xs->if_id != tsa->if_id) {

if_id exists in policy and state, but you are checking only state.

> +		netdev_err(ns->netdev, "unmatched if_id %d %d\n",
> +			   xs->if_id, tsa->if_id);
> +		return false;
> +	}

It is worth to add check for having XFRM_XMIT flag here.

> +
>  	ipsec->tx++;
>  
>  	return true;
> diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
> index bf02efa10956..4941b6e46d0a 100644
> --- a/drivers/net/netdevsim/netdevsim.h
> +++ b/drivers/net/netdevsim/netdevsim.h
> @@ -41,6 +41,7 @@ struct nsim_sa {
>  	__be32 ipaddr[4];
>  	u32 key[4];
>  	u32 salt;
> +	u32 if_id;
>  	bool used;
>  	bool crypt;
>  	bool rx;
> diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
> index e5722c95b8bb..a12588e7b060 100644
> --- a/net/xfrm/xfrm_output.c
> +++ b/net/xfrm/xfrm_output.c
> @@ -706,6 +706,8 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
>  	struct xfrm_state *x = skb_dst(skb)->xfrm;
>  	int family;
>  	int err;
> +	struct xfrm_offload *xo;
> +	struct sec_path *sp;
>  
>  	family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
>  		: skb_dst(skb)->ops->family;
> @@ -728,6 +730,25 @@ int xfrm_output(struct sock *sk, struct sk_buff *skb)
>  			kfree_skb(skb);
>  			return -EHOSTUNREACH;
>  		}

I think that code below should be set under "if (x->if_id)".

Thanks

> +		sp = secpath_set(skb);
> +		if (!sp) {
> +			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
> +			kfree_skb(skb);
> +			return -ENOMEM;
> +		}
> +
> +		sp->olen++;
> +		sp->xvec[sp->len++] = x;
> +		xfrm_state_hold(x);
> +
> +		xo = xfrm_offload(skb);
> +		if (!xo) {
> +			secpath_reset(skb);
> +			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
> +			kfree_skb(skb);
> +			return -EINVAL;
> +		}
> +		xo->flags |= XFRM_XMIT;
>  
>  		return xfrm_output_resume(sk, skb, 0);
>  	}
> -- 
> 2.47.0.199.ga7371fff76-goog
> 
>