linux-stable/include/uapi/linux/seg6.h
Gustavo A. R. Silva 94dfc73e7c treewide: uapi: Replace zero-length arrays with flexible-array members
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:

../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
		strcpy(de3->name, ".");
		^

Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2022-06-28 21:26:05 +02:00

55 lines
1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
* SR-IPv6 implementation
*
* Author:
* David Lebrun <david.lebrun@uclouvain.be>
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _UAPI_LINUX_SEG6_H
#define _UAPI_LINUX_SEG6_H
#include <linux/types.h>
#include <linux/in6.h> /* For struct in6_addr. */
/*
* SRH
*/
struct ipv6_sr_hdr {
__u8 nexthdr;
__u8 hdrlen;
__u8 type;
__u8 segments_left;
__u8 first_segment; /* Represents the last_entry field of SRH */
__u8 flags;
__u16 tag;
struct in6_addr segments[];
};
#define SR6_FLAG1_PROTECTED (1 << 6)
#define SR6_FLAG1_OAM (1 << 5)
#define SR6_FLAG1_ALERT (1 << 4)
#define SR6_FLAG1_HMAC (1 << 3)
#define SR6_TLV_INGRESS 1
#define SR6_TLV_EGRESS 2
#define SR6_TLV_OPAQUE 3
#define SR6_TLV_PADDING 4
#define SR6_TLV_HMAC 5
#define sr_has_hmac(srh) ((srh)->flags & SR6_FLAG1_HMAC)
struct sr6_tlv {
__u8 type;
__u8 len;
__u8 data[0];
};
#endif