Re: [PATCH nf-next v2] netfilter:nft_meta: add NFT_META_VLAN support

[Nikolay Aleksandrov <nikolay@cumulusnetworks.com>]

On 05/07/2019 16:16, wenxu@ucloud.cn wrote:
> From: wenxu <wenxu@ucloud.cn>
> 
> This patch provide a meta vlan to set the vlan tag of the packet.
> 
> for q-in-q outer vlan id 20:
> meta vlan set 0x88a8:20
> 
> set the default 0x8100 vlan type with vlan id 20
> meta vlan set 20
> 
> Signed-off-by: wenxu <wenxu@ucloud.cn>
> ---
>  include/net/netfilter/nft_meta.h         |  5 ++++-
>  include/uapi/linux/netfilter/nf_tables.h |  4 ++++
>  net/netfilter/nft_meta.c                 | 25 +++++++++++++++++++++++++
>  3 files changed, 33 insertions(+), 1 deletion(-)
> 

The patch looks fine, just a note: you'll only be able to work with the
outer tag, so guessing to achieve a double-tagged frame you'll have to
add another NFT_META_VLAN_INNER(?) and will have to organize them one
after another.

Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

> diff --git a/include/net/netfilter/nft_meta.h b/include/net/netfilter/nft_meta.h
> index 5c69e9b..cb0f1e8 100644
> --- a/include/net/netfilter/nft_meta.h
> +++ b/include/net/netfilter/nft_meta.h
> @@ -6,7 +6,10 @@ struct nft_meta {
>  	enum nft_meta_keys	key:8;
>  	union {
>  		enum nft_registers	dreg:8;
> -		enum nft_registers	sreg:8;
> +		struct {
> +			enum nft_registers	sreg:8;
> +			enum nft_registers	sreg2:8;
> +		};
>  	};
>  };
>  
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index a0d1dbd..699524a 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -797,6 +797,7 @@ enum nft_exthdr_attributes {
>   * @NFT_META_OIFKIND: packet output interface kind name (dev->rtnl_link_ops->kind)
>   * @NFT_META_BRI_IIFPVID: packet input bridge port pvid
>   * @NFT_META_BRI_IIFVPROTO: packet input bridge vlan proto
> + * @NFT_META_VLAN: packet vlan metadata
>   */
>  enum nft_meta_keys {
>  	NFT_META_LEN,
> @@ -829,6 +830,7 @@ enum nft_meta_keys {
>  	NFT_META_OIFKIND,
>  	NFT_META_BRI_IIFPVID,
>  	NFT_META_BRI_IIFVPROTO,
> +	NFT_META_VLAN,
>  };
>  
>  /**
> @@ -895,12 +897,14 @@ enum nft_hash_attributes {
>   * @NFTA_META_DREG: destination register (NLA_U32)
>   * @NFTA_META_KEY: meta data item to load (NLA_U32: nft_meta_keys)
>   * @NFTA_META_SREG: source register (NLA_U32)
> + * @NFTA_META_SREG2: source register (NLA_U32)
>   */
>  enum nft_meta_attributes {
>  	NFTA_META_UNSPEC,
>  	NFTA_META_DREG,
>  	NFTA_META_KEY,
>  	NFTA_META_SREG,
> +	NFTA_META_SREG2,
>  	__NFTA_META_MAX
>  };
>  #define NFTA_META_MAX		(__NFTA_META_MAX - 1)
> diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
> index 18a848b..fb3d12e 100644
> --- a/net/netfilter/nft_meta.c
> +++ b/net/netfilter/nft_meta.c
> @@ -271,6 +271,20 @@ void nft_meta_set_eval(const struct nft_expr *expr,
>  		skb->secmark = value;
>  		break;
>  #endif
> +	case NFT_META_VLAN: {
> +		u32 *sreg2 = &regs->data[meta->sreg2];
> +		u16 vlan_proto;
> +		u16 vlan_tci;
> +
> +		vlan_tci = nft_reg_load16(sreg);
> +		vlan_proto = nft_reg_load16(sreg2);
> +
> +		if (vlan_proto != ETH_P_8021Q && vlan_proto != ETH_P_8021AD)
> +			return;
> +
> +		__vlan_hwaccel_put_tag(skb, htons(vlan_proto), vlan_tci & VLAN_VID_MASK);
> +		break;
> +	}
>  	default:
>  		WARN_ON(1);
>  	}
> @@ -281,6 +295,7 @@ void nft_meta_set_eval(const struct nft_expr *expr,
>  	[NFTA_META_DREG]	= { .type = NLA_U32 },
>  	[NFTA_META_KEY]		= { .type = NLA_U32 },
>  	[NFTA_META_SREG]	= { .type = NLA_U32 },
> +	[NFTA_META_SREG2]	= { .type = NLA_U32 },
>  };
>  EXPORT_SYMBOL_GPL(nft_meta_policy);
>  
> @@ -432,6 +447,13 @@ int nft_meta_set_init(const struct nft_ctx *ctx,
>  	case NFT_META_PKTTYPE:
>  		len = sizeof(u8);
>  		break;
> +	case NFT_META_VLAN:
> +		len = sizeof(u16);
> +		priv->sreg2 = nft_parse_register(tb[NFTA_META_SREG2]);
> +		err = nft_validate_register_load(priv->sreg2, len);
> +		if (err < 0)
> +			return err;
> +		break;
>  	default:
>  		return -EOPNOTSUPP;
>  	}
> @@ -457,6 +479,9 @@ int nft_meta_get_dump(struct sk_buff *skb,
>  		goto nla_put_failure;
>  	if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
>  		goto nla_put_failure;
> +	if (priv->key == NFT_META_VLAN &&
> +	    nft_dump_register(skb, NFTA_META_SREG2, priv->sreg2))
> +		goto nla_put_failure;
>  	return 0;
>  
>  nla_put_failure:
>