net sched actions: skbedit add support for mod-ing skb pkt_type

Extremely useful for setting packet type to host so i dont
have to modify the dst mac address using pedit (which requires
that i know the mac address)

Example usage:
tc filter add dev eth0 parent ffff: protocol ip pref 9 u32 \
match ip src 5.5.5.5/32 \
flowid 1:5 action skbedit ptype host

This will tag all packets incoming from 5.5.5.5 with type
PACKET_HOST
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tc_act/tc_skbedit.h

@@ -28,7 +28,7 @@ struct tcf_skbedit {
 	u32		priority;
 	u32		mark;
 	u16		queue_mapping;
-	/* XXX: 16-bit pad here? */
+	u16		ptype;
 };
 #define to_skbedit(a) \
 	container_of(a->priv, struct tcf_skbedit, common)

include/uapi/linux/tc_act/tc_skbedit.h

@@ -27,6 +27,7 @@
 #define SKBEDIT_F_PRIORITY		0x1
 #define SKBEDIT_F_QUEUE_MAPPING		0x2
 #define SKBEDIT_F_MARK			0x4
+#define SKBEDIT_F_PTYPE			0x8
 
 struct tc_skbedit {
 	tc_gen;
@@ -40,6 +41,7 @@ enum {
 	TCA_SKBEDIT_QUEUE_MAPPING,
 	TCA_SKBEDIT_MARK,
 	TCA_SKBEDIT_PAD,
+	TCA_SKBEDIT_PTYPE,
 	__TCA_SKBEDIT_MAX
 };
 #define TCA_SKBEDIT_MAX (__TCA_SKBEDIT_MAX - 1)

net/sched/act_skbedit.c

@@ -47,6 +47,8 @@ static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a,
 		skb_set_queue_mapping(skb, d->queue_mapping);
 	if (d->flags & SKBEDIT_F_MARK)
 		skb->mark = d->mark;
+	if (d->flags & SKBEDIT_F_PTYPE)
+		skb->pkt_type = d->ptype;
 
 	spin_unlock(&d->tcf_lock);
 	return d->tcf_action;
@@ -57,6 +59,7 @@ static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
 	[TCA_SKBEDIT_PRIORITY]		= { .len = sizeof(u32) },
 	[TCA_SKBEDIT_QUEUE_MAPPING]	= { .len = sizeof(u16) },
 	[TCA_SKBEDIT_MARK]		= { .len = sizeof(u32) },
+	[TCA_SKBEDIT_PTYPE]		= { .len = sizeof(u16) },
 };
 
 static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
@@ -68,7 +71,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 	struct tc_skbedit *parm;
 	struct tcf_skbedit *d;
 	u32 flags = 0, *priority = NULL, *mark = NULL;
-	u16 *queue_mapping = NULL;
+	u16 *queue_mapping = NULL, *ptype = NULL;
 	bool exists = false;
 	int ret = 0, err;
 
@@ -92,6 +95,13 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 		queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
 	}
 
+	if (tb[TCA_SKBEDIT_PTYPE] != NULL) {
+		ptype = nla_data(tb[TCA_SKBEDIT_PTYPE]);
+		if (!skb_pkt_type_ok(*ptype))
+			return -EINVAL;
+		flags |= SKBEDIT_F_PTYPE;
+	}
+
 	if (tb[TCA_SKBEDIT_MARK] != NULL) {
 		flags |= SKBEDIT_F_MARK;
 		mark = nla_data(tb[TCA_SKBEDIT_MARK]);
@@ -132,6 +142,8 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 		d->queue_mapping = *queue_mapping;
 	if (flags & SKBEDIT_F_MARK)
 		d->mark = *mark;
+	if (flags & SKBEDIT_F_PTYPE)
+		d->ptype = *ptype;
 
 	d->tcf_action = parm->action;
 
@@ -169,6 +181,10 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
 	    nla_put(skb, TCA_SKBEDIT_MARK, sizeof(d->mark),
 		    &d->mark))
 		goto nla_put_failure;
+	if ((d->flags & SKBEDIT_F_PTYPE) &&
+	    nla_put(skb, TCA_SKBEDIT_PTYPE, sizeof(d->ptype),
+		    &d->ptype))
+		goto nla_put_failure;
 
 	tcf_tm_dump(&t, &d->tcf_tm);
 	if (nla_put_64bit(skb, TCA_SKBEDIT_TM, sizeof(t), &t, TCA_SKBEDIT_PAD))