From 6e9d0d578fdf90901507dd9f9929d0e6fcdd3211 Mon Sep 17 00:00:00 2001
From: Michael Jeanson <mjeanson@efficios.com>
Date: Wed, 26 Jan 2022 14:49:11 -0500
Subject: [PATCH 6/7] fix: net: skb: introduce kfree_skb_reason() (v5.17)

See upstream commit :

  commit c504e5c2f9648a1e5c2be01e8c3f59d394192bd3
  Author: Menglong Dong <imagedong@tencent.com>
  Date:   Sun Jan 9 14:36:26 2022 +0800

    net: skb: introduce kfree_skb_reason()

    Introduce the interface kfree_skb_reason(), which is able to pass
    the reason why the skb is dropped to 'kfree_skb' tracepoint.

    Add the 'reason' field to 'trace_kfree_skb', therefor user can get
    more detail information about abnormal skb with 'drop_monitor' or
    eBPF.

    All drop reasons are defined in the enum 'skb_drop_reason', and
    they will be print as string in 'kfree_skb' tracepoint in format
    of 'reason: XXX'.

    ( Maybe the reasons should be defined in a uapi header file, so that
    user space can use them? )

Upstream-Status: Backport [lttng-modules commit 6e9d0d578fdf90901507dd9f9929d0e6fcdd3211]

Change-Id: I6766678a288da959498a4736fc3f95bf239c3e94
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 include/instrumentation/events/skb.h | 31 ++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/include/instrumentation/events/skb.h b/include/instrumentation/events/skb.h
index d6579363..c6d7095d 100644
--- a/include/instrumentation/events/skb.h
+++ b/include/instrumentation/events/skb.h
@@ -13,6 +13,36 @@
 /*
  * Tracepoint for free an sk_buff:
  */
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,17,0))
+LTTNG_TRACEPOINT_ENUM(skb_drop_reason,
+	TP_ENUM_VALUES(
+		ctf_enum_value("NOT_SPECIFIED",	SKB_DROP_REASON_NOT_SPECIFIED)
+		ctf_enum_value("NO_SOCKET",	SKB_DROP_REASON_NO_SOCKET)
+		ctf_enum_value("PKT_TOO_SMALL",	SKB_DROP_REASON_PKT_TOO_SMALL)
+		ctf_enum_value("TCP_CSUM",	SKB_DROP_REASON_TCP_CSUM)
+		ctf_enum_value("TCP_FILTER",	SKB_DROP_REASON_TCP_FILTER)
+		ctf_enum_value("UDP_CSUM",	SKB_DROP_REASON_UDP_CSUM)
+		ctf_enum_value("MAX",		SKB_DROP_REASON_MAX)
+	)
+)
+
+LTTNG_TRACEPOINT_EVENT_MAP(kfree_skb,
+
+	skb_kfree,
+
+	TP_PROTO(struct sk_buff *skb, void *location,
+		enum skb_drop_reason reason),
+
+	TP_ARGS(skb, location, reason),
+
+	TP_FIELDS(
+		ctf_integer_hex(void *, skbaddr, skb)
+		ctf_integer_hex(void *, location, location)
+		ctf_integer_network(unsigned short, protocol, skb->protocol)
+		ctf_enum(skb_drop_reason, uint8_t, reason, reason)
+	)
+)
+#else
 LTTNG_TRACEPOINT_EVENT_MAP(kfree_skb,
 
 	skb_kfree,
@@ -27,6 +57,7 @@ LTTNG_TRACEPOINT_EVENT_MAP(kfree_skb,
 		ctf_integer_network(unsigned short, protocol, skb->protocol)
 	)
 )
+#endif
 
 LTTNG_TRACEPOINT_EVENT_MAP(consume_skb,
 
-- 
2.19.1