Subject: Re: [RFC PATCH net-next v4 2/4] net/sched: flower: Add PPPoE filter

From: Guillaume Nault <[email-masked]>
Date: Fri, 8 Jul 2022 21:22:53 +0200

On Fri, Jul 08, 2022 at 02:24:19PM +0200, Marcin Szycik wrote:
> From: Wojciech Drewek <[email-masked]>
> 
> Add support for PPPoE specific fields for tc-flower.
> Those fields can be provided only when protocol was set
> to ETH_P_PPP_SES. Defines, dump, load and set are being done here.
> 
> Overwrite basic.n_proto only in case of PPP_IP and PPP_IPV6,

... and PPP_MPLS_UC/PPP_MPLS_MC in this new patch version.

> otherwise leave it as ETH_P_PPP_SES.
> 
> Signed-off-by: Wojciech Drewek <[email-masked]>
> ---
> v4:
>   * support of MPLS inner fields
>   * session_id stored in __be16
> 
>  include/uapi/linux/pkt_cls.h |  3 ++
>  net/sched/cls_flower.c       | 61 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 64 insertions(+)
> 
> diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
> index 9a2ee1e39fad..c142c0f8ed8a 100644
> --- a/include/uapi/linux/pkt_cls.h
> +++ b/include/uapi/linux/pkt_cls.h
> @@ -589,6 +589,9 @@ enum {
>  
>  	TCA_FLOWER_KEY_NUM_OF_VLANS,    /* u8 */
>  
> +	TCA_FLOWER_KEY_PPPOE_SID,	/* be16 */
> +	TCA_FLOWER_KEY_PPP_PROTO,	/* be16 */
> +
>  	__TCA_FLOWER_MAX,
>  };
>  
> diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
> index dcca70144dff..2a0ebad0e61c 100644
> --- a/net/sched/cls_flower.c
> +++ b/net/sched/cls_flower.c
> @@ -16,6 +16,7 @@
>  #include <linux/in6.h>
>  #include <linux/ip.h>
>  #include <linux/mpls.h>
> +#include <linux/ppp_defs.h>
>  
>  #include <net/sch_generic.h>
>  #include <net/pkt_cls.h>
> @@ -73,6 +74,7 @@ struct fl_flow_key {
>  	struct flow_dissector_key_ct ct;
>  	struct flow_dissector_key_hash hash;
>  	struct flow_dissector_key_num_of_vlans num_of_vlans;
> +	struct flow_dissector_key_pppoe pppoe;
>  } __aligned(BITS_PER_LONG / 8); /* Ensure that we can do comparisons as longs. */
>  
>  struct fl_flow_mask_range {
> @@ -714,6 +716,8 @@ static const struct nla_policy fl_policy[TCA_FLOWER_MAX + 1] = {
>  	[TCA_FLOWER_KEY_HASH]		= { .type = NLA_U32 },
>  	[TCA_FLOWER_KEY_HASH_MASK]	= { .type = NLA_U32 },
>  	[TCA_FLOWER_KEY_NUM_OF_VLANS]	= { .type = NLA_U8 },
> +	[TCA_FLOWER_KEY_PPPOE_SID]	= { .type = NLA_U16 },
> +	[TCA_FLOWER_KEY_PPP_PROTO]	= { .type = NLA_U16 },
>  
>  };
>  
> @@ -1041,6 +1045,50 @@ static void fl_set_key_vlan(struct nlattr **tb,
>  	}
>  }
>  
> +static void fl_set_key_pppoe(struct nlattr **tb,
> +			     struct flow_dissector_key_pppoe *key_val,
> +			     struct flow_dissector_key_pppoe *key_mask,
> +			     struct fl_flow_key *key,
> +			     struct fl_flow_key *mask)
> +{
> +	/* key_val::type must be set to ETH_P_PPP_SES
> +	 * because ETH_P_PPP_SES was stored in basic.n_proto
> +	 * which might get overwritten by ppp_proto
> +	 * or might be set to 0, the role of key_val::type
> +	 * is simmilar to vlan_key::tpid

Didn't you mean "vlan_tpid"?

> +	 */
> +	key_val->type = htons(ETH_P_PPP_SES);
> +	key_mask->type = cpu_to_be16(~0);
> +
> +	if (tb[TCA_FLOWER_KEY_PPPOE_SID]) {
> +		key_val->session_id =
> +			nla_get_be16(tb[TCA_FLOWER_KEY_PPPOE_SID]);
> +		key_mask->session_id = cpu_to_be16(~0);
> +	}
> +	if (tb[TCA_FLOWER_KEY_PPP_PROTO]) {
> +		key_val->ppp_proto =
> +			nla_get_be16(tb[TCA_FLOWER_KEY_PPP_PROTO]);
> +		key_mask->ppp_proto = cpu_to_be16(~0);
> +
> +		if (key_val->ppp_proto == htons(PPP_IP)) {
> +			key->basic.n_proto = htons(ETH_P_IP);
> +			mask->basic.n_proto = cpu_to_be16(~0);
> +		} else if (key_val->ppp_proto == htons(PPP_IPV6)) {
> +			key->basic.n_proto = htons(ETH_P_IPV6);
> +			mask->basic.n_proto = cpu_to_be16(~0);
> +		} else if (key_val->ppp_proto == htons(PPP_MPLS_UC)) {
> +			key->basic.n_proto = htons(ETH_P_MPLS_UC);
> +			mask->basic.n_proto = cpu_to_be16(~0);
> +		} else if (key_val->ppp_proto == htons(PPP_MPLS_MC)) {
> +			key->basic.n_proto = htons(ETH_P_MPLS_MC);
> +			mask->basic.n_proto = cpu_to_be16(~0);
> +		}
> +	} else {
> +		key->basic.n_proto = 0;
> +		mask->basic.n_proto = cpu_to_be16(0);
> +	}
> +}
> +
>  static void fl_set_key_flag(u32 flower_key, u32 flower_mask,
>  			    u32 *dissector_key, u32 *dissector_mask,
>  			    u32 flower_flag_bit, u32 dissector_flag_bit)
> @@ -1651,6 +1699,9 @@ static int fl_set_key(struct net *net, struct nlattr **tb,
>  		}
>  	}
>  
> +	if (key->basic.n_proto == htons(ETH_P_PPP_SES))
> +		fl_set_key_pppoe(tb, &key->pppoe, &mask->pppoe, key, mask);
> +
>  	if (key->basic.n_proto == htons(ETH_P_IP) ||
>  	    key->basic.n_proto == htons(ETH_P_IPV6)) {
>  		fl_set_key_val(tb, &key->basic.ip_proto, TCA_FLOWER_KEY_IP_PROTO,
> @@ -1923,6 +1974,8 @@ static void fl_init_dissector(struct flow_dissector *dissector,
>  			     FLOW_DISSECTOR_KEY_HASH, hash);
>  	FL_KEY_SET_IF_MASKED(mask, keys, cnt,
>  			     FLOW_DISSECTOR_KEY_NUM_OF_VLANS, num_of_vlans);
> +	FL_KEY_SET_IF_MASKED(mask, keys, cnt,
> +			     FLOW_DISSECTOR_KEY_PPPOE, pppoe);
>  
>  	skb_flow_dissector_init(dissector, keys, cnt);
>  }
> @@ -3051,6 +3104,14 @@ static int fl_dump_key(struct sk_buff *skb, struct net *net,
>  	    fl_dump_key_ip(skb, false, &key->ip, &mask->ip)))
>  		goto nla_put_failure;
>  
> +	if (mask->pppoe.session_id &&
> +	    nla_put_be16(skb, TCA_FLOWER_KEY_PPPOE_SID, key->pppoe.session_id))
> +		goto nla_put_failure;
> +
> +	if (mask->basic.n_proto && mask->pppoe.ppp_proto &&
> +	    nla_put_be16(skb, TCA_FLOWER_KEY_PPP_PROTO, key->pppoe.ppp_proto))
> +		goto nla_put_failure;
> +
>  	if (key->control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS &&
>  	    (fl_dump_key_val(skb, &key->ipv4.src, TCA_FLOWER_KEY_IPV4_SRC,
>  			     &mask->ipv4.src, TCA_FLOWER_KEY_IPV4_SRC_MASK,
> -- 
> 2.35.1
>