netdev - Re: [PATCH net-next v6 02/10] eth: Move IPv4/IPv6 multicast address bases to their own symbols

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Message-ID: <03660271-c04c-4872-8483-b3a1bfa568ef@intel.com>
Date: Tue, 9 Apr 2024 11:07:20 +0200
From: Alexander Lobakin <aleksander.lobakin@...el.com>
To: Diogo Ivo <diogo.ivo@...mens.com>
CC: <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <netdev@...r.kernel.org>, <andrew@...n.ch>,
	<danishanwar@...com>, <rogerq@...nel.org>, <vigneshr@...com>,
	<jan.kiszka@...mens.com>
Subject: Re: [PATCH net-next v6 02/10] eth: Move IPv4/IPv6 multicast address
 bases to their own symbols

From: Diogo Ivo <diogo.ivo@...mens.com>
Date: Wed,  3 Apr 2024 11:48:12 +0100

> As these addresses can be useful outside of checking if an address
> is a multicast address (for example in device drivers) make them
> accessible to users of etherdevice.h to avoid code duplication.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@...mens.com>
> Reviewed-by: MD Danish Anwar <danishanwar@...com>
> ---
> Changes in v5: 
>  - Added Reviewed-by tag from Danish 
> 
>  include/linux/etherdevice.h | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
> index 224645f17c33..8d6daf828427 100644
> --- a/include/linux/etherdevice.h
> +++ b/include/linux/etherdevice.h
> @@ -71,6 +71,12 @@ static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
>  { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
>  #define eth_stp_addr eth_reserved_addr_base
>  
> +static const u8 eth_ipv4_mcast_addr_base[ETH_ALEN] __aligned(2) =
> +{ 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
> +
> +static const u8 eth_ipv6_mcast_addr_base[ETH_ALEN] __aligned(2) =
> +{ 0x33, 0x33, 0x00, 0x00, 0x00, 0x00 };

I see this is applied already, but I don't like static symbols in header
files. This will make a local copy of every used symbol each time it's
referenced.
We usually make such symbols global consts and export them. Could you
please send a follow-up?

> +
>  /**
>   * is_link_local_ether_addr - Determine if given Ethernet address is link-local
>   * @addr: Pointer to a six-byte array containing the Ethernet address
> @@ -430,18 +436,16 @@ static inline bool ether_addr_equal_masked(const u8 *addr1, const u8 *addr2,
>  
>  static inline bool ether_addr_is_ipv4_mcast(const u8 *addr)
>  {
> -	u8 base[ETH_ALEN] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
>  	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0xff, 0x80, 0x00, 0x00 };
>  
> -	return ether_addr_equal_masked(addr, base, mask);
> +	return ether_addr_equal_masked(addr, eth_ipv4_mcast_addr_base, mask);
>  }
>  
>  static inline bool ether_addr_is_ipv6_mcast(const u8 *addr)
>  {
> -	u8 base[ETH_ALEN] = { 0x33, 0x33, 0x00, 0x00, 0x00, 0x00 };
>  	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
>  
> -	return ether_addr_equal_masked(addr, base, mask);
> +	return ether_addr_equal_masked(addr, eth_ipv6_mcast_addr_base, mask);
>  }
>  
>  static inline bool ether_addr_is_ip_mcast(const u8 *addr)

Thanks,
Olek