openvswitch: add trace points

This makes openvswitch module use the event tracing framework
to log the upcall interface and action execution pipeline.  When
using openvswitch as the packet forwarding engine, some types of
debugging are made possible simply by using the ovs-vswitchd's
ofproto/trace command.  However, such a command has some
limitations:

  1. When trying to trace packets that go through the CT action,
     the state of the packet can't be determined, and probably
     would be potentially wrong.

  2. Deducing problem packets can sometimes be difficult as well
     even if many of the flows are known

  3. It's possible to use the openvswitch module even without
     the ovs-vswitchd (although, not common use).

Introduce the event tracing points here to make it possible for
working through these problems in kernel space.  The style is
copied from the mac80211 driver-trace / trace code for
consistency - this creates some checkpatch splats, but the
official 'guide' for adding tracepoints, as well as the existing
examples all add the same splats so it seems acceptable.
Signed-off-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/Makefile

@@ -13,6 +13,7 @@ openvswitch-y := \
 	flow_netlink.o \
 	flow_table.o \
 	meter.o \
+	openvswitch_trace.o \
 	vport.o \
 	vport-internal_dev.o \
 	vport-netdev.o
@@ -24,3 +25,5 @@ endif
 obj-$(CONFIG_OPENVSWITCH_VXLAN)+= vport-vxlan.o
 obj-$(CONFIG_OPENVSWITCH_GENEVE)+= vport-geneve.o
 obj-$(CONFIG_OPENVSWITCH_GRE)	+= vport-gre.o
+
+CFLAGS_openvswitch_trace.o = -I$(src)

net/openvswitch/actions.c

@@ -30,6 +30,7 @@
 #include "conntrack.h"
 #include "vport.h"
 #include "flow_netlink.h"
+#include "openvswitch_trace.h"
 
 struct deferred_action {
 	struct sk_buff *skb;
@@ -1242,6 +1243,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 	     a = nla_next(a, &rem)) {
 		int err = 0;
 
+		if (trace_ovs_do_execute_action_enabled())
+			trace_ovs_do_execute_action(dp, skb, key, a, rem);
+
 		switch (nla_type(a)) {
 		case OVS_ACTION_ATTR_OUTPUT: {
 			int port = nla_get_u32(a);

net/openvswitch/datapath.c

@@ -43,6 +43,7 @@
 #include "flow_table.h"
 #include "flow_netlink.h"
 #include "meter.h"
+#include "openvswitch_trace.h"
 #include "vport-internal_dev.h"
 #include "vport-netdev.h"
 
@@ -275,6 +276,9 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
 	struct dp_stats_percpu *stats;
 	int err;
 
+	if (trace_ovs_dp_upcall_enabled())
+		trace_ovs_dp_upcall(dp, skb, key, upcall_info);
+
 	if (upcall_info->portid == 0) {
 		err = -ENOTCONN;
 		goto err;

net/openvswitch/openvswitch_trace.c

+// SPDX-License-Identifier: GPL-2.0
+/* bug in tracepoint.h, it should include this */
+#include <linux/module.h>
+
+/* sparse isn't too happy with all macros... */
+#ifndef __CHECKER__
+#define CREATE_TRACE_POINTS
+#include "openvswitch_trace.h"
+
+#endif

net/openvswitch/openvswitch_trace.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM openvswitch
+
+#if !defined(_TRACE_OPENVSWITCH_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_OPENVSWITCH_H
+
+#include <linux/tracepoint.h>
+
+#include "datapath.h"
+
+TRACE_EVENT(ovs_do_execute_action,
+
+	TP_PROTO(struct datapath *dp, struct sk_buff *skb,
+		 struct sw_flow_key *key, const struct nlattr *a, int rem),
+
+	TP_ARGS(dp, skb, key, a, rem),
+
+	TP_STRUCT__entry(
+		__field(	void *,		dpaddr			)
+		__string(	dp_name,	ovs_dp_name(dp)		)
+		__string(	dev_name,	skb->dev->name		)
+		__field(	void *,		skbaddr			)
+		__field(	unsigned int,	len			)
+		__field(	unsigned int,	data_len		)
+		__field(	unsigned int,	truesize		)
+		__field(	u8,		nr_frags		)
+		__field(	u16,		gso_size		)
+		__field(	u16,		gso_type		)
+		__field(	u32,		ovs_flow_hash		)
+		__field(	u32,		recirc_id		)
+		__field(	void *,		keyaddr			)
+		__field(	u16,		key_eth_type		)
+		__field(	u8,		key_ct_state		)
+		__field(	u8,		key_ct_orig_proto	)
+		__field(	u16,		key_ct_zone		)
+		__field(	unsigned int,	flow_key_valid		)
+		__field(	u8,		action_type		)
+		__field(	unsigned int,	action_len		)
+		__field(	void *,		action_data		)
+		__field(	u8,		is_last			)
+	),
+
+	TP_fast_assign(
+		__entry->dpaddr = dp;
+		__assign_str(dp_name, ovs_dp_name(dp));
+		__assign_str(dev_name, skb->dev->name);
+		__entry->skbaddr = skb;
+		__entry->len = skb->len;
+		__entry->data_len = skb->data_len;
+		__entry->truesize = skb->truesize;
+		__entry->nr_frags = skb_shinfo(skb)->nr_frags;
+		__entry->gso_size = skb_shinfo(skb)->gso_size;
+		__entry->gso_type = skb_shinfo(skb)->gso_type;
+		__entry->ovs_flow_hash = key->ovs_flow_hash;
+		__entry->recirc_id = key->recirc_id;
+		__entry->keyaddr = key;
+		__entry->key_eth_type = key->eth.type;
+		__entry->key_ct_state = key->ct_state;
+		__entry->key_ct_orig_proto = key->ct_orig_proto;
+		__entry->key_ct_zone = key->ct_zone;
+		__entry->flow_key_valid = !(key->mac_proto & SW_FLOW_KEY_INVALID);
+		__entry->action_type = nla_type(a);
+		__entry->action_len = nla_len(a);
+		__entry->action_data = nla_data(a);
+		__entry->is_last = nla_is_last(a, rem);
+	),
+
+	TP_printk("dpaddr=%p dp_name=%s dev=%s skbaddr=%p len=%u data_len=%u truesize=%u nr_frags=%d gso_size=%d gso_type=%#x ovs_flow_hash=0x%08x recirc_id=0x%08x keyaddr=%p eth_type=0x%04x ct_state=%02x ct_orig_proto=%02x ct_Zone=%04x flow_key_valid=%d action_type=%u action_len=%u action_data=%p is_last=%d",
+		  __entry->dpaddr, __get_str(dp_name), __get_str(dev_name),
+		  __entry->skbaddr, __entry->len, __entry->data_len,
+		  __entry->truesize, __entry->nr_frags, __entry->gso_size,
+		  __entry->gso_type, __entry->ovs_flow_hash,
+		  __entry->recirc_id, __entry->keyaddr, __entry->key_eth_type,
+		  __entry->key_ct_state, __entry->key_ct_orig_proto,
+		  __entry->key_ct_zone,
+		  __entry->flow_key_valid,
+		  __entry->action_type, __entry->action_len,
+		  __entry->action_data, __entry->is_last)
+);
+
+TRACE_EVENT(ovs_dp_upcall,
+
+	TP_PROTO(struct datapath *dp, struct sk_buff *skb,
+		 const struct sw_flow_key *key,
+		 const struct dp_upcall_info *upcall_info),
+
+	TP_ARGS(dp, skb, key, upcall_info),
+
+	TP_STRUCT__entry(
+		__field(	void *,		dpaddr			)
+		__string(	dp_name,	ovs_dp_name(dp)		)
+		__string(	dev_name,	skb->dev->name		)
+		__field(	void *,		skbaddr			)
+		__field(	unsigned int,	len			)
+		__field(	unsigned int,	data_len		)
+		__field(	unsigned int,	truesize		)
+		__field(	u8,		nr_frags		)
+		__field(	u16,		gso_size		)
+		__field(	u16,		gso_type		)
+		__field(	u32,		ovs_flow_hash		)
+		__field(	u32,		recirc_id		)
+		__field(	const void *,	keyaddr			)
+		__field(	u16,		key_eth_type		)
+		__field(	u8,		key_ct_state		)
+		__field(	u8,		key_ct_orig_proto	)
+		__field(	u16,		key_ct_zone		)
+		__field(	unsigned int,	flow_key_valid		)
+		__field(	u8,		upcall_cmd		)
+		__field(	u32,		upcall_port		)
+		__field(	u16,		upcall_mru		)
+	),
+
+	TP_fast_assign(
+		__entry->dpaddr = dp;
+		__assign_str(dp_name, ovs_dp_name(dp));
+		__assign_str(dev_name, skb->dev->name);
+		__entry->skbaddr = skb;
+		__entry->len = skb->len;
+		__entry->data_len = skb->data_len;
+		__entry->truesize = skb->truesize;
+		__entry->nr_frags = skb_shinfo(skb)->nr_frags;
+		__entry->gso_size = skb_shinfo(skb)->gso_size;
+		__entry->gso_type = skb_shinfo(skb)->gso_type;
+		__entry->ovs_flow_hash = key->ovs_flow_hash;
+		__entry->recirc_id = key->recirc_id;
+		__entry->keyaddr = key;
+		__entry->key_eth_type = key->eth.type;
+		__entry->key_ct_state = key->ct_state;
+		__entry->key_ct_orig_proto = key->ct_orig_proto;
+		__entry->key_ct_zone = key->ct_zone;
+		__entry->flow_key_valid =  !(key->mac_proto & SW_FLOW_KEY_INVALID);
+		__entry->upcall_cmd = upcall_info->cmd;
+		__entry->upcall_port = upcall_info->portid;
+		__entry->upcall_mru = upcall_info->mru;
+	),
+
+	TP_printk("dpaddr=%p dp_name=%s dev=%s skbaddr=%p len=%u data_len=%u truesize=%u nr_frags=%d gso_size=%d gso_type=%#x ovs_flow_hash=0x%08x recirc_id=0x%08x keyaddr=%p eth_type=0x%04x ct_state=%02x ct_orig_proto=%02x ct_zone=%04x flow_key_valid=%d upcall_cmd=%u upcall_port=%u upcall_mru=%u",
+		  __entry->dpaddr, __get_str(dp_name), __get_str(dev_name),
+		  __entry->skbaddr, __entry->len, __entry->data_len,
+		  __entry->truesize, __entry->nr_frags, __entry->gso_size,
+		  __entry->gso_type, __entry->ovs_flow_hash,
+		  __entry->recirc_id, __entry->keyaddr, __entry->key_eth_type,
+		  __entry->key_ct_state, __entry->key_ct_orig_proto,
+		  __entry->key_ct_zone,
+		  __entry->flow_key_valid,
+		  __entry->upcall_cmd, __entry->upcall_port,
+		  __entry->upcall_mru)
+);
+
+#endif /* _TRACE_OPENVSWITCH_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE openvswitch_trace
+#include <trace/define_trace.h>