[PATCH net-next 2/7] xdp: tracepoint xdp_redirect also need a map argument

[Jesper Dangaard Brouer <brouer@redhat.com>]

To make sense of the map index, the tracepoint user also need to know
that map we are talking about.  Supply the map pointer but only expose
the map->id.

The 'to_index' is renamed 'to_ifindex'.  In the xdp_redirect_map case,
this is the result of the devmap lookup. The map lookup key is exposed
as map_index, which is needed to troubleshoot in case the lookup failed.
The 'to_ifindex' is placed after 'err' to keep TP_STRUCT as common as
possible.

This also keeps the TP_STRUCT similar enough, that userspace can write
a monitor program, that doesn't need to care about whether
bpf_redirect or bpf_redirect_map were used.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
 include/trace/events/xdp.h |   38 ++++++++++++++++++++++++++++++--------
 net/core/filter.c          |    6 +++---
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index f684f3b36bca..573dcfa1aeaa 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -49,20 +49,23 @@ TRACE_EVENT(xdp_exception,
 		  __entry->ifindex)
 );
 
-TRACE_EVENT(xdp_redirect,
+DECLARE_EVENT_CLASS(xdp_redirect_template,
 
 	TP_PROTO(const struct net_device *dev,
 		 const struct bpf_prog *xdp,
-		 int to_index, int err),
+		 int to_ifindex, int err,
+		 const struct bpf_map *map, u32 map_index),
 
-	TP_ARGS(dev, xdp, to_index, err),
+	TP_ARGS(dev, xdp, to_ifindex, err, map, map_index),
 
 	TP_STRUCT__entry(
 		__array(u8, prog_tag, 8)
 		__field(u32, act)
 		__field(int, ifindex)
-		__field(int, to_index)
 		__field(int, err)
+		__field(int, to_ifindex)
+		__field(u32, map_id)
+		__field(int, map_index)
 	),
 
 	TP_fast_assign(
@@ -70,16 +73,35 @@ TRACE_EVENT(xdp_redirect,
 		memcpy(__entry->prog_tag, xdp->tag, sizeof(xdp->tag));
 		__entry->act		= XDP_REDIRECT;
 		__entry->ifindex	= dev->ifindex;
-		__entry->to_index	= to_index;
 		__entry->err		= err;
+		__entry->to_ifindex	= to_ifindex;
+		__entry->map_id		= map ? map->id : 0;
+		__entry->map_index	= map_index;
 	),
 
-	TP_printk("prog=%s action=%s ifindex=%d to_index=%d err=%d",
+	TP_printk("prog=%s action=%s ifindex=%d to_ifindex=%d err=%d"
+		  " map_id=%d map_index=%d",
 		  __print_hex_str(__entry->prog_tag, 8),
 		  __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB),
-		  __entry->ifindex, __entry->to_index,
-		  __entry->err)
+		  __entry->ifindex, __entry->to_ifindex,
+		  __entry->err,
+		  __entry->map_id, __entry->map_index)
 );
+
+DEFINE_EVENT(xdp_redirect_template, xdp_redirect,
+	TP_PROTO(const struct net_device *dev,
+		 const struct bpf_prog *xdp,
+		 int to_ifindex, int err,
+		 const struct bpf_map *map, u32 map_index),
+	TP_ARGS(dev, xdp, to_ifindex, err, map, map_index)
+);
+
+#define _trace_xdp_redirect(dev, xdp, to, err)	\
+	 trace_xdp_redirect(dev, xdp, to, err, NULL, 0);
+
+#define trace_xdp_redirect_map(dev, xdp, fwd, err, map, idx)	\
+	trace_xdp_redirect(dev, xdp, fwd ? fwd->ifindex : 0, err, map, idx);
+
 #endif /* _TRACE_XDP_H */
 
 #include <trace/define_trace.h>
diff --git a/net/core/filter.c b/net/core/filter.c
index de31fb684ad4..31eab77cc842 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2524,7 +2524,7 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
 	if (likely(!err))
 		ri->map_to_flush = map;
 out:
-	trace_xdp_redirect(dev, xdp_prog, index, err);
+	trace_xdp_redirect_map(dev, xdp_prog, fwd, err, map, index);
 	return err;
 }
 
@@ -2548,7 +2548,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
 
 	err = __bpf_tx_xdp(fwd, NULL, xdp, 0);
 out:
-	trace_xdp_redirect(dev, xdp_prog, index, err);
+	_trace_xdp_redirect(dev, xdp_prog, index, err);
 	return err;
 }
 EXPORT_SYMBOL_GPL(xdp_do_redirect);
@@ -2582,7 +2582,7 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
 
 	skb->dev = fwd;
 out:
-	trace_xdp_redirect(dev, xdp_prog, index, err);
+	_trace_xdp_redirect(dev, xdp_prog, index, err);
 	return err;
 }
 EXPORT_SYMBOL_GPL(xdp_do_generic_redirect);