Re: [PATCH net-next 2/2] cls_flower: add support for matching MPLS labels

[Jiri Pirko <jiri@resnulli.us>]

Mon, Mar 27, 2017 at 08:16:02PM CEST, benjamin.lahaise@netronome.com wrote:
>Add support to tc flower to match based on fields in MPLS labels (TTL, 
>Bottom of Stack, TC field, Label).

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>
>Signed-off-by: Benjamin LaHaise <benjamin.lahaise@netronome.com>
>Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
>Reviewed-by: Simon Horman <simon.horman@netronome.com>
>Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>
>diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h
>index 7a69f2a..f1129e3 100644
>--- a/include/uapi/linux/pkt_cls.h
>+++ b/include/uapi/linux/pkt_cls.h
>@@ -432,6 +432,11 @@ enum {
> 	TCA_FLOWER_KEY_ARP_THA,		/* ETH_ALEN */
> 	TCA_FLOWER_KEY_ARP_THA_MASK,	/* ETH_ALEN */
> 
>+	TCA_FLOWER_KEY_MPLS_TTL,	/* u8 - 8 bits */
>+	TCA_FLOWER_KEY_MPLS_BOS,	/* u8 - 1 bit */
>+	TCA_FLOWER_KEY_MPLS_TC,		/* u8 - 3 bits */
>+	TCA_FLOWER_KEY_MPLS_LABEL,	/* be32 - 20 bits */
>+
> 	__TCA_FLOWER_MAX,
> };
> 
>diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
>index 9d0c99d..24619f9 100644
>--- a/net/sched/cls_flower.c
>+++ b/net/sched/cls_flower.c
>@@ -18,6 +18,7 @@
> #include <linux/if_ether.h>
> #include <linux/in6.h>
> #include <linux/ip.h>
>+#include <linux/mpls.h>
> 
> #include <net/sch_generic.h>
> #include <net/pkt_cls.h>
>@@ -47,6 +48,7 @@ struct fl_flow_key {
> 		struct flow_dissector_key_ipv6_addrs enc_ipv6;
> 	};
> 	struct flow_dissector_key_ports enc_tp;
>+	struct flow_dissector_key_mpls mpls;
> } __aligned(BITS_PER_LONG / 8); /* Ensure that we can do comparisons as longs. */
> 
> struct fl_flow_mask_range {
>@@ -423,6 +425,10 @@ static const struct nla_policy fl_policy[TCA_FLOWER_MAX + 1] = {
> 	[TCA_FLOWER_KEY_ARP_SHA_MASK]	= { .len = ETH_ALEN },
> 	[TCA_FLOWER_KEY_ARP_THA]	= { .len = ETH_ALEN },
> 	[TCA_FLOWER_KEY_ARP_THA_MASK]	= { .len = ETH_ALEN },
>+	[TCA_FLOWER_KEY_MPLS_TTL]	= { .type = NLA_U8 },
>+	[TCA_FLOWER_KEY_MPLS_BOS]	= { .type = NLA_U8 },
>+	[TCA_FLOWER_KEY_MPLS_TC]	= { .type = NLA_U8 },
>+	[TCA_FLOWER_KEY_MPLS_LABEL]	= { .type = NLA_U32 },
> };
> 
> static void fl_set_key_val(struct nlattr **tb,
>@@ -438,6 +444,36 @@ static void fl_set_key_val(struct nlattr **tb,
> 		memcpy(mask, nla_data(tb[mask_type]), len);
> }
> 
>+static void fl_set_key_mpls(struct nlattr **tb,
>+			    struct flow_dissector_key_mpls *key_val,
>+			    struct flow_dissector_key_mpls *key_mask)
>+{
>+#define MPLS_TTL_MASK	(MPLS_LS_TTL_MASK >> MPLS_LS_TTL_SHIFT)
>+#define MPLS_BOS_MASK	(MPLS_LS_S_MASK >> MPLS_LS_S_SHIFT)
>+#define MPLS_TC_MASK	(MPLS_LS_TC_MASK >> MPLS_LS_TC_SHIFT)
>+#define MPLS_LABEL_MASK	(MPLS_LS_LABEL_MASK >> MPLS_LS_LABEL_SHIFT)
>+
>+	if (tb[TCA_FLOWER_KEY_MPLS_TTL]) {
>+		key_val->mpls_ttl = nla_get_u8(tb[TCA_FLOWER_KEY_MPLS_TTL]);
>+		key_mask->mpls_ttl = MPLS_TTL_MASK;
>+	}
>+	if (tb[TCA_FLOWER_KEY_MPLS_BOS]) {
>+		key_val->mpls_bos = nla_get_u8(tb[TCA_FLOWER_KEY_MPLS_BOS]);
>+		key_mask->mpls_bos = MPLS_BOS_MASK;
>+	}
>+	if (tb[TCA_FLOWER_KEY_MPLS_TC]) {
>+		key_val->mpls_tc =
>+			nla_get_u8(tb[TCA_FLOWER_KEY_MPLS_TC]) & MPLS_TC_MASK;
>+		key_mask->mpls_tc = MPLS_TC_MASK;
>+	}
>+	if (tb[TCA_FLOWER_KEY_MPLS_LABEL]) {
>+		key_val->mpls_label =
>+			nla_get_u32(tb[TCA_FLOWER_KEY_MPLS_LABEL]) &
>+			MPLS_LABEL_MASK;
>+		key_mask->mpls_label = MPLS_LABEL_MASK;
>+	}
>+}
>+
> static void fl_set_key_vlan(struct nlattr **tb,
> 			    struct flow_dissector_key_vlan *key_val,
> 			    struct flow_dissector_key_vlan *key_mask)
>@@ -594,6 +630,9 @@ static int fl_set_key(struct net *net, struct nlattr **tb,
> 			       &mask->icmp.code,
> 			       TCA_FLOWER_KEY_ICMPV6_CODE_MASK,
> 			       sizeof(key->icmp.code));
>+	} else if (key->basic.n_proto == htons(ETH_P_MPLS_UC) ||
>+		   key->basic.n_proto == htons(ETH_P_MPLS_MC)) {
>+		fl_set_key_mpls(tb, &key->mpls, &mask->mpls);
> 	} else if (key->basic.n_proto == htons(ETH_P_ARP) ||
> 		   key->basic.n_proto == htons(ETH_P_RARP)) {
> 		fl_set_key_val(tb, &key->arp.sip, TCA_FLOWER_KEY_ARP_SIP,
>@@ -730,6 +769,8 @@ static void fl_init_dissector(struct cls_fl_head *head,
> 	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
> 			     FLOW_DISSECTOR_KEY_ARP, arp);
> 	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
>+			     FLOW_DISSECTOR_KEY_MPLS, mpls);
>+	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
> 			     FLOW_DISSECTOR_KEY_VLAN, vlan);
> 	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
> 			     FLOW_DISSECTOR_KEY_ENC_KEYID, enc_key_id);
>@@ -994,6 +1035,41 @@ static int fl_dump_key_val(struct sk_buff *skb,
> 	return 0;
> }
> 
>+static int fl_dump_key_mpls(struct sk_buff *skb,
>+			    struct flow_dissector_key_mpls *mpls_key,
>+			    struct flow_dissector_key_mpls *mpls_mask)
>+{
>+	int err;
>+
>+	if (!memchr_inv(mpls_mask, 0, sizeof(*mpls_mask)))
>+		return 0;
>+	if (mpls_mask->mpls_ttl) {
>+		err = nla_put_u8(skb, TCA_FLOWER_KEY_MPLS_TTL,
>+				 mpls_key->mpls_ttl);
>+		if (err)
>+			return err;
>+	}
>+	if (mpls_mask->mpls_tc) {
>+		err = nla_put_u8(skb, TCA_FLOWER_KEY_MPLS_TC,
>+				 mpls_key->mpls_tc);
>+		if (err)
>+			return err;
>+	}
>+	if (mpls_mask->mpls_label) {
>+		err = nla_put_u32(skb, TCA_FLOWER_KEY_MPLS_LABEL,
>+				  mpls_key->mpls_label);
>+		if (err)
>+			return err;
>+	}
>+	if (mpls_mask->mpls_bos) {
>+		err = nla_put_u8(skb, TCA_FLOWER_KEY_MPLS_BOS,
>+				 mpls_key->mpls_bos);
>+		if (err)
>+			return err;
>+	}
>+	return 0;
>+}
>+
> static int fl_dump_key_vlan(struct sk_buff *skb,
> 			    struct flow_dissector_key_vlan *vlan_key,
> 			    struct flow_dissector_key_vlan *vlan_mask)
>@@ -1099,6 +1175,9 @@ static int fl_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
> 			    sizeof(key->basic.n_proto)))
> 		goto nla_put_failure;
> 
>+	if (fl_dump_key_mpls(skb, &key->mpls, &mask->mpls))
>+		goto nla_put_failure;
>+
> 	if (fl_dump_key_vlan(skb, &key->vlan, &mask->vlan))
> 		goto nla_put_failure;
> 
>