1 files changed, 32 insertions, 12 deletions

diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index 8d17a543cc9f..762ceec3e6f6 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 #include <linux/rtnetlink.h>
+#include <net/inet_ecn.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/pkt_cls.h>
@@ -21,15 +22,13 @@
 static unsigned int skbmod_net_id;
 static struct tc_action_ops act_skbmod_ops;
 
-#define MAX_EDIT_LEN ETH_HLEN
 static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a,
 			  struct tcf_result *res)
 {
 	struct tcf_skbmod *d = to_skbmod(a);
-	int action;
+	int action, max_edit_len, err;
 	struct tcf_skbmod_params *p;
 	u64 flags;
-	int err;
 
 	tcf_lastuse_update(&d->tcf_tm);
 	bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
@@ -38,19 +37,34 @@ static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a,
 	if (unlikely(action == TC_ACT_SHOT))
 		goto drop;
 
-	if (!skb->dev || skb->dev->type != ARPHRD_ETHER)
-		return action;
+	max_edit_len = skb_mac_header_len(skb);
+	p = rcu_dereference_bh(d->skbmod_p);
+	flags = p->flags;
+
+	/* tcf_skbmod_init() guarantees "flags" to be one of the following:
+	 *	1. a combination of SKBMOD_F_{DMAC,SMAC,ETYPE}
+	 *	2. SKBMOD_F_SWAPMAC
+	 *	3. SKBMOD_F_ECN
+	 * SKBMOD_F_ECN only works with IP packets; all other flags only work with Ethernet
+	 * packets.
+	 */
+	if (flags == SKBMOD_F_ECN) {
+		switch (skb_protocol(skb, true)) {
+		case cpu_to_be16(ETH_P_IP):
+		case cpu_to_be16(ETH_P_IPV6):
+			max_edit_len += skb_network_header_len(skb);
+			break;
+		default:
+			goto out;
+		}
+	} else if (!skb->dev || skb->dev->type != ARPHRD_ETHER) {
+		goto out;
+	}
 
-	/* XXX: if you are going to edit more fields beyond ethernet header
-	 * (example when you add IP header replacement or vlan swap)
-	 * then MAX_EDIT_LEN needs to change appropriately
-	*/
-	err = skb_ensure_writable(skb, MAX_EDIT_LEN);
+	err = skb_ensure_writable(skb, max_edit_len);
 	if (unlikely(err)) /* best policy is to drop on the floor */
 		goto drop;
 
-	p = rcu_dereference_bh(d->skbmod_p);
-	flags = p->flags;
 	if (flags & SKBMOD_F_DMAC)
 		ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst);
 	if (flags & SKBMOD_F_SMAC)
@@ -66,6 +80,10 @@ static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a,
 		ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr);
 	}
 
+	if (flags & SKBMOD_F_ECN)
+		INET_ECN_set_ce(skb);
+
+out:
 	return action;
 
 drop:
@@ -129,6 +147,8 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	index = parm->index;
 	if (parm->flags & SKBMOD_F_SWAPMAC)
 		lflags = SKBMOD_F_SWAPMAC;
+	if (parm->flags & SKBMOD_F_ECN)
+		lflags = SKBMOD_F_ECN;
 
 	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)