svn commit: r336628 - head/sys/net

[O. Hartmann]

On Mon, 23 Jul 2018 07:11:58 +0000 (UTC)
Eugene Grosbein <eugen at FreeBSD.org> wrote:

> Author: eugen
> Date: Mon Jul 23 07:11:58 2018
> New Revision: 336628
> URL: https://svnweb.freebsd.org/changeset/base/336628
> 
> Log:
>   epair(4): make sure we do not duplicate MAC addresses
>   in case of reused if_index.
>   
>   PR:		229957
>   Tested by:	O. Hartmann <ohartmann at walstatt.org>
>   Approved by:	avg (mentor)
> 
> Modified:
>   head/sys/net/if_epair.c
> 
> Modified: head/sys/net/if_epair.c
> ==============================================================================
> --- head/sys/net/if_epair.c	Mon Jul 23 06:38:48 2018	(r336627)
> +++ head/sys/net/if_epair.c	Mon Jul 23 07:11:58 2018	(r336628)
> @@ -107,6 +107,7 @@ static int epair_clone_create(struct if_clone *, char 
>  static int epair_clone_destroy(struct if_clone *, struct ifnet *);
>  
>  static const char epairname[] = "epair";
> +static unsigned int next_index = 0;
>  
>  /* Netisr related definitions and sysctl. */
>  static struct netisr_handler epair_nh = {
> @@ -843,12 +844,22 @@ epair_clone_create(struct if_clone *ifc, char *name, s
>  
>  	/*
>  	 * Calculate the etheraddr hashing the hostid and the
> -	 * interface index. The result would be hopefully unique
> +	 * interface index. The result would be hopefully unique.
> +	 * Note that the "a" component of an epair instance may get moved
> +	 * to a different VNET after creation. In that case its index
> +	 * will be freed and the index can get reused by new epair instance.
> +	 * Make sure we do not create same etheraddr again.
>  	 */
>  	getcredhostid(curthread->td_ucred, (unsigned long *)&hostid);
>  	if (hostid == 0) 
>  		arc4rand(&hostid, sizeof(hostid), 0);
> -	key[0] = (uint32_t)ifp->if_index;
> +
> +	if (ifp->if_index > next_index)
> +		next_index = ifp->if_index;
> +	else
> +		next_index++;
> +
> +	key[0] = (uint32_t)next_index;
>  	key[1] = (uint32_t)(hostid & 0xffffffff);
>  	key[2] = (uint32_t)((hostid >> 32) & 0xfffffffff);
>  	hash = jenkins_hash32(key, 3, 0);
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Thank you very much for the pretty fast patch!

Regards,
oh