From: "Gustavo A. R. Silva" <gustavo...@kernel.org>
Date: Tue, 15 Oct 2024 18:32:43 -0600
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
>
> Address the following warnings by changing the type of the middle struct
> members in a couple of composite structs, which are currently causing
> trouble, from `struct sockaddr` to `struct sockaddr_legacy`. Note that
> the latter struct doesn't contain a flexible-array member.
>
> include/uapi/linux/if_arp.h:118:25: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
> include/uapi/linux/if_arp.h:119:25: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
> include/uapi/linux/if_arp.h:121:25: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
> include/uapi/linux/if_arp.h:126:25: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
> include/uapi/linux/if_arp.h:127:25: warning: structure containing a flexible
> array member is not at the end of another structure
> [-Wflex-array-member-not-at-end]
>
> Also, update some related code, accordingly.
>
> No binary differences are present after these changes.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
> ---
> include/uapi/linux/if_arp.h | 18 +++++++++---------
> net/ipv4/arp.c | 2 +-
> 2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/include/uapi/linux/if_arp.h b/include/uapi/linux/if_arp.h
> index 4783af9fe520..cb6813f7783a 100644
> --- a/include/uapi/linux/if_arp.h
> +++ b/include/uapi/linux/if_arp.h
> @@ -115,18 +115,18 @@
>
> /* ARP ioctl request. */
> struct arpreq {
> - struct sockaddr arp_pa; /* protocol address */
> - struct sockaddr arp_ha; /* hardware address */
> - int arp_flags; /* flags */
> - struct sockaddr arp_netmask; /* netmask (only for proxy arps) */
> - char arp_dev[IFNAMSIZ];
> + struct sockaddr_legacy arp_pa; /* protocol address
> */
> + struct sockaddr_legacy arp_ha; /* hardware address
> */
> + int arp_flags; /* flags
> */
> + struct sockaddr_legacy arp_netmask; /* netmask (only for proxy
> arps) */
> + char arp_dev[IFNAMSIZ];
> };
>
> struct arpreq_old {
> - struct sockaddr arp_pa; /* protocol address */
> - struct sockaddr arp_ha; /* hardware address */
> - int arp_flags; /* flags */
> - struct sockaddr arp_netmask; /* netmask (only for proxy arps) */
> + struct sockaddr_legacy arp_pa; /* protocol address
> */
> + struct sockaddr_legacy arp_ha; /* hardware address
> */
> + int arp_flags; /* flags
> */
> + struct sockaddr arp_netmask; /* netmask (only for proxy
> arps) */
I think we can use _legacy here too, 14 bytes are enough for ARP.
But whichever is fine to me because arpreq_old is not used in
kernel, so
Reviewed-by: Kuniyuki Iwashima <kun...@amazon.com>
> };
>
> /* ARP Flag values. */
> diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
> index 11c1519b3699..3a97efe1587b 100644
> --- a/net/ipv4/arp.c
> +++ b/net/ipv4/arp.c
> @@ -1185,7 +1185,7 @@ static int arp_req_get(struct net *net, struct arpreq
> *r)
>
> read_lock_bh(&neigh->lock);
> memcpy(r->arp_ha.sa_data, neigh->ha,
> - min(dev->addr_len, sizeof(r->arp_ha.sa_data_min)));
> + min(dev->addr_len, sizeof(r->arp_ha.sa_data)));
> r->arp_flags = arp_state_to_flags(neigh);
> read_unlock_bh(&neigh->lock);
>
> --
> 2.34.1
