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? )

Change-Id: I6766678a288da959498a4736fc3f95bf239c3e94
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/include/instrumentation/events/skb.h b/include/instrumentation/events/skb.h
index d6579363b55866e7ec4c3b81a2c49576d21d92b0..c6d7095dbb589b98ff443926c028550e34f1220f 100644 (file)
--- 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,