net: sched: introduce a TRAP control action

There is need to instruct the HW offloaded path to push certain matched
packets to cpu/kernel for further analysis. So this patch introduces a
new TRAP control action to TC.

For kernel datapath, this action does not make much sense. So with the
same logic as in HW, new TRAP behaves similar to STOLEN. The skb is just
dropped in the datapath (and virtually ejected to an upper level, which
does not exist in case of kernel).

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_cls.h

@@ -37,6 +37,13 @@ enum {
 #define TC_ACT_QUEUED		5
 #define TC_ACT_REPEAT		6
 #define TC_ACT_REDIRECT		7
+#define TC_ACT_TRAP		8 /* For hw path, this means "trap to cpu"
+				   * and don't further process the frame
+				   * in hardware. For sw path, this is
+				   * equivalent of TC_ACT_STOLEN - drop
+				   * the skb and act like everything
+				   * is alright.
+				   */
 
 /* There is a special kind of actions called "extended actions",
  * which need a value parameter. These have a local opcode located in

net/core/dev.c

@@ -3269,6 +3269,7 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
 		return NULL;
 	case TC_ACT_STOLEN:
 	case TC_ACT_QUEUED:
+	case TC_ACT_TRAP:
 		*ret = NET_XMIT_SUCCESS;
 		consume_skb(skb);
 		return NULL;
@@ -4038,6 +4039,7 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
 		return NULL;
 	case TC_ACT_STOLEN:
 	case TC_ACT_QUEUED:
+	case TC_ACT_TRAP:
 		consume_skb(skb);
 		return NULL;
 	case TC_ACT_REDIRECT:

net/sched/cls_bpf.c

@@ -70,6 +70,7 @@ static int cls_bpf_exec_opcode(int code)
 	case TC_ACT_OK:
 	case TC_ACT_SHOT:
 	case TC_ACT_STOLEN:
+	case TC_ACT_TRAP:
 	case TC_ACT_REDIRECT:
 	case TC_ACT_UNSPEC:
 		return code;

net/sched/sch_atm.c

@@ -406,6 +406,7 @@ done:
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			__qdisc_drop(skb, to_free);
 			return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:

net/sched/sch_cbq.c

@@ -254,6 +254,7 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_drr.c

@@ -339,6 +339,7 @@ static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_dsmark.c

@@ -243,6 +243,7 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 #ifdef CONFIG_NET_CLS_ACT
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			__qdisc_drop(skb, to_free);
 			return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 

net/sched/sch_fq_codel.c

@@ -103,6 +103,7 @@ static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
 		switch (result) {
 		case TC_ACT_STOLEN:
 		case TC_ACT_QUEUED:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return 0;

net/sched/sch_hfsc.c

@@ -1155,6 +1155,7 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_htb.c

@@ -238,6 +238,7 @@ static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_multiq.c

@@ -52,6 +52,7 @@ multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 	switch (err) {
 	case TC_ACT_STOLEN:
 	case TC_ACT_QUEUED:
+	case TC_ACT_TRAP:
 		*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 	case TC_ACT_SHOT:
 		return NULL;

net/sched/sch_prio.c

@@ -48,6 +48,7 @@ prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 		switch (err) {
 		case TC_ACT_STOLEN:
 		case TC_ACT_QUEUED:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_qfq.c

@@ -726,6 +726,7 @@ static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
 		switch (result) {
 		case TC_ACT_QUEUED:
 		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return NULL;

net/sched/sch_sfb.c

@@ -266,6 +266,7 @@ static bool sfb_classify(struct sk_buff *skb, struct tcf_proto *fl,
 		switch (result) {
 		case TC_ACT_STOLEN:
 		case TC_ACT_QUEUED:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return false;

net/sched/sch_sfq.c

@@ -187,6 +187,7 @@ static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
 		switch (result) {
 		case TC_ACT_STOLEN:
 		case TC_ACT_QUEUED:
+		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 		case TC_ACT_SHOT:
 			return 0;