flow: Fix using pointer to member of packed struct icmp6_hdr.

OVS has no structure definition for ICMPv6 header with additional
data. More precisely, it has, but this structure named as
'icmp6_error_header' and only suitable to store error related
extended information.  'flow_compose_l4' stores additional
information in reserved bits by using system defined structure
'icmp6_hdr', which is marked as 'packed' and this leads to
build failure with gcc >= 9:

  lib/flow.c:3041:34: error:
    taking address of packed member of 'struct icmp6_hdr' may result
    in an unaligned pointer value [-Werror=address-of-packed-member]

        uint32_t *reserved = &icmp->icmp6_dataun.icmp6_un_data32[0];
                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix that by renaming 'icmp6_error_header' to 'icmp6_data_header'
and allowing it to store not only errors, but any type of additional
information by analogue with 'struct icmp6_hdr'.
All the usages of 'struct icmp6_hdr' replaced with this new structure.
Removed redundant conversions between network and host representations.
Now fields are always in be.

This also, probably, makes flow_compose_l4 more robust by avoiding
possible unaligned accesses to 32 bit value.

Fixes: 9b2b84973db7 ("Support for match & set ICMPv6 reserved and options type fields")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: William Tu <u9012063@gmail.com>
Acked-by: Ben Pfaff <blp@ovn.org>

0 files changed, 0 insertions, 0 deletions