Re: [PATCH net-next,v3 11/11] netfilter: nf_tables: add hardware offload support

Jiri Pirko
2019-07-09T06:21:02Z

Tue, Jul 09, 2019 at 03:44:37AM CEST, jakub.kicinski@netronome.com wrote:
>On Mon, 8 Jul 2019 18:06:13 +0200, Pablo Neira Ayuso wrote:
>> This patch adds hardware offload support for nftables through the
>> existing netdev_ops->ndo_setup_tc() interface, the TC_SETUP_CLSFLOWER
>> classifier and the flow rule API. This hardware offload support is
>> available for the NFPROTO_NETDEV family and the ingress hook.
>>
>> Each nftables expression has a new ->offload interface, that is used to
>> populate the flow rule object that is attached to the transaction
>> object.
>>
>> There is a new per-table NFT_TABLE_F_HW flag, that is set on to offload
>> an entire table, including all of its chains.
>>
>> This patch supports for basic metadata (layer 3 and 4 protocol numbers),
>> 5-tuple payload matching and the accept/drop actions; this also includes
>> basechain hardware offload only.
>>
>> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
>
>Any particular reason to not fence this off with a device feature
>(ethtool -k)? Then you wouldn't need that per-driver list abomination
>until drivers start advertising it.. IDK if we want the per-device
>offload enable flags or not in general, it seems like a good idea in
>general for admin to be able to disable offload per device 🤷
>
>> +static int nft_flow_offload_rule(struct nft_trans *trans,
>> + enum tc_fl_command command)
>> +{
>> + struct nft_flow_rule *flow = nft_trans_flow_rule(trans);
>> + struct nft_rule *rule = nft_trans_rule(trans);
>> + struct tc_cls_flower_offload cls_flower = {};
>> + struct nft_base_chain *basechain;
>> + struct netlink_ext_ack extack;
>> + __be16 proto = ETH_P_ALL;
>> +
>> + if (!nft_is_base_chain(trans->ctx.chain))
>> + return -EOPNOTSUPP;
>> +
>> + basechain = nft_base_chain(trans->ctx.chain);
>> +
>> + if (flow)
>> + proto = flow->proto;
>> +
>> + nft_flow_offload_common_init(&cls_flower.common, proto, &extack);
>> + cls_flower.command = command;
>> + cls_flower.cookie = (unsigned long) rule;
>> + if (flow)
>> + cls_flower.rule = flow->rule;
>> +
>> + return nft_setup_cb_call(basechain, TC_SETUP_CLSFLOWER, &cls_flower);
>> +}
>
>Are we 100% okay with using TC cls_flower structures and defines in nft
>code?

Yeah, your right. Should be renamed and moved to "flow offload" as well.