Re: let vlan(4) mtu be limited by the parents hardmtu instead of current mtu

[Chris Cappuccio]

ok chris@ 

David Gwynne [da...@gwynne.id.au] wrote:
> this lets you have networks on the "native" vlan on an interface
> at 1500, while setting a child vlan interfaces mtu to jumbos.
> 
> ok?
> 
> Index: if_vlan.c
> ===================================================================
> RCS file: /cvs/src/sys/net/if_vlan.c,v
> retrieving revision 1.108
> diff -u -p -r1.108 if_vlan.c
> --- if_vlan.c 12 Jul 2014 18:44:22 -0000      1.108
> +++ if_vlan.c 19 Aug 2014 23:52:15 -0000
> @@ -528,9 +528,9 @@ vlan_ioctl(struct ifnet *ifp, u_long cmd
>       case SIOCSIFMTU:
>               if (ifv->ifv_p != NULL) {
>                       if (ifv->ifv_p->if_capabilities & IFCAP_VLAN_MTU)
> -                             p_mtu = ifv->ifv_p->if_mtu;
> +                             p_mtu = ifv->ifv_p->if_hardmtu;
>                       else
> -                             p_mtu = ifv->ifv_p->if_mtu - EVL_ENCAPLEN;
> +                             p_mtu = ifv->ifv_p->if_hardmtu - EVL_ENCAPLEN;
>                       
>                       if (ifr->ifr_mtu > p_mtu || ifr->ifr_mtu < ETHERMIN)
>                               error = EINVAL;