[PATCH FYI 1/1] tools headers uapi: Update linux/in.h copy

[arnaldo.melo@gmail.com]

tldr; Just FYI, I'm carrying this on the perf tools tree.

- Arnaldo

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
  	[0] = "NORMAL",
  	[1] = "RANDOM",
  	[2] = "SEQUENTIAL",
  	[3] = "WILLNEED",
  	[4] = "DONTNEED",
  	[5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

---

To get the changes in:

  65b32f801bfbc54d ("uapi: move IPPROTO_L2TP to in.h")
  5854a09b49574da5 ("net/ipv4: Use __DECLARE_FLEX_ARRAY() helper")

That ends up automatically adding the new IPPROTO_L2TP to the socket
args beautifiers:

  $ tools/perf/trace/beauty/socket.sh > before
  $ cp include/uapi/linux/in.h tools/include/uapi/linux/in.h
  $ tools/perf/trace/beauty/socket.sh > after
  $ diff -u before after
  --- before	2022-10-25 12:17:02.577892416 -0300
  +++ after	2022-10-25 12:17:10.806113033 -0300
  @@ -20,6 +20,7 @@
   	[98] = "ENCAP",
   	[103] = "PIM",
   	[108] = "COMP",
  +	[115] = "L2TP",
   	[132] = "SCTP",
   	[136] = "UDPLITE",
   	[137] = "MPLS",
  $

Now 'perf trace' will decode that 115 into "L2TP" and it will also be
possible to use it in tracepoint filter expressions.

Addresses this tools/perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/in.h' differs from latest version at 'include/uapi/linux/in.h'
  diff -u tools/include/uapi/linux/in.h include/uapi/linux/in.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Wojciech Drewek <wojciech.drewek@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/include/uapi/linux/in.h | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/tools/include/uapi/linux/in.h b/tools/include/uapi/linux/in.h
index 14168225cecdc74c..f243ce665f74f82d 100644
--- a/tools/include/uapi/linux/in.h
+++ b/tools/include/uapi/linux/in.h
@@ -68,6 +68,8 @@ enum {
 #define IPPROTO_PIM		IPPROTO_PIM
   IPPROTO_COMP = 108,		/* Compression Header Protocol		*/
 #define IPPROTO_COMP		IPPROTO_COMP
+  IPPROTO_L2TP = 115,		/* Layer 2 Tunnelling Protocol		*/
+#define IPPROTO_L2TP		IPPROTO_L2TP
   IPPROTO_SCTP = 132,		/* Stream Control Transport Protocol	*/
 #define IPPROTO_SCTP		IPPROTO_SCTP
   IPPROTO_UDPLITE = 136,	/* UDP-Lite (RFC 3828)			*/
@@ -188,21 +190,13 @@ struct ip_mreq_source {
 };
 
 struct ip_msfilter {
+	__be32		imsf_multiaddr;
+	__be32		imsf_interface;
+	__u32		imsf_fmode;
+	__u32		imsf_numsrc;
 	union {
-		struct {
-			__be32		imsf_multiaddr_aux;
-			__be32		imsf_interface_aux;
-			__u32		imsf_fmode_aux;
-			__u32		imsf_numsrc_aux;
-			__be32		imsf_slist[1];
-		};
-		struct {
-			__be32		imsf_multiaddr;
-			__be32		imsf_interface;
-			__u32		imsf_fmode;
-			__u32		imsf_numsrc;
-			__be32		imsf_slist_flex[];
-		};
+		__be32		imsf_slist[1];
+		__DECLARE_FLEX_ARRAY(__be32, imsf_slist_flex);
 	};
 };
 
-- 
2.37.3