[PATCH v2 09/10] net: lib: add ether_addr_inc() helper

[Ahmad Fatoum]

On 04.10.23 08:41, Sascha Hauer wrote:
> On Mon, Oct 02, 2023 at 12:16:53PM +0200, Oleksij Rempel wrote:
>> Add helper function to calculate Ethernet address by incriminating it.
>> This helper can be used for multiport devices like switches to generate
>> address for each port based on one stored address.
>>
>> Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
>> ---
>>  include/net.h |  1 +
>>  net/lib.c     | 25 +++++++++++++++++++++++++
>>  2 files changed, 26 insertions(+)
>>
>> diff --git a/include/net.h b/include/net.h
>> index a0ef8bee04..fe82451cc9 100644
>> --- a/include/net.h
>> +++ b/include/net.h
>> @@ -360,6 +360,7 @@ int setenv_ip(const char *name, IPaddr_t ip);
>>  
>>  int string_to_ethaddr(const char *str, u8 enetaddr[6]);
>>  void ethaddr_to_string(const u8 enetaddr[6], char *str);
>> +void ether_addr_inc(u8 *dst_addr, const u8 *src_addr, u32 increment);
>>  
>>  #ifdef CONFIG_NET_RESOLV
>>  int resolv(const char *host, IPaddr_t *ip);
>> diff --git a/net/lib.c b/net/lib.c
>> index d4536441bd..dc7d83bc6d 100644
>> --- a/net/lib.c
>> +++ b/net/lib.c
>> @@ -44,6 +44,31 @@ void ethaddr_to_string(const u8 enetaddr[ETH_ALEN], char *str)
>>  		 enetaddr[4], enetaddr[5]);
>>  }
>>  
>> +/**
>> + * ether_addr_inc - Increment an Ethernet address.
>> + * @dst_addr: Destination address to store the incremented address.
>> + * @src_addr: Source address to be incremented.
>> + * @increment: Value by which to increment the source address.
>> + *
>> + * This function increments the given source Ethernet address by
>> + * the specified increment value, storing the result in the
>> + * destination address.
>> + */
>> +void ether_addr_inc(u8 *dst_addr, const u8 *src_addr, u32 increment)
>> +{
>> +	u32 value;
>> +	int i;
>> +
>> +	for(i = 0; i < 6; ++i)
>> +		dst_addr[i] = src_addr[i];
>> +
>> +	for(i = 5; i >= 0 && increment; --i) {
>> +		value = dst_addr[i] + increment;
>> +		dst_addr[i] = value & 0xFF;
>> +		increment = value >> 8;
>> +	}
>> +}
> 
> The Kernel already has eth_addr_add() and more helpers. How about
> adopting these instead?

I had copied them over here: https://lore.barebox.org/barebox/20230911155927.3786335-2-a.fatoum@pengutronix.de/
They got reverted along with patch 1/3 in that series, but they have no dependency, so could be reinstated.


> 
> Sascha
> 

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