adding if_dev member to struct ifnet

[Vincent Jardin]

> > messier BD>example is in the new ATM code where interfaces are looked up
> > by name.
> >
> > Where is this?
>
> One example would be in sys/netatm/atm_if.c around line 1081.

Do you mean pif_name and pif_unit ?

This code could be updated. It uses pif_unit and pif_name that could become 
pif_xname.

     for (pip = atm_interface_head; pip; pip = pip->pif_next) {
             if (strcmp(pip->pif_xname, n) == 0)
                     break;
     }

instead of
     for (pip = atm_interface_head; pip; pip = pip->pif_next) {
             if ((pip->pif_unit == unit) && (strcmp(pip->pif_name, n) == 0))
                     break;
     }

Moreover, a PIF (Physical IF) is not an ifnet. It is the ATM device. The ATM 
PVC are the NIF (Network IF -> ifnet). They are many NIF (PVC) over a single 
PIF (ATM device).

With the ATM stack, the main issue is related to AIOCS_SET_NIF. It sets the 
ifp's if_name to the NIF's nif_name and the ifp's if_unit to a regular 
counter.

In fact we could change the following code
                    strcpy ( nip->nif_name, asr->asr_nif_pref );
                    nip->nif_sel = count;

                    ifp->if_name = nip->nif_name;
                    ifp->if_unit = count;

   to

                    snprintf(nip->nif_xname, sizeof(nip->nif_xname), "%s%d",
                       asr->asr_nif_pref, count);
                    nip->nif_sel = count; /* we need to keep a selector to 
build the UNI ATM address  */

                    ifp->if_xname = nip->nif_xname;
#if 0
                    ifp->if_unit = count; /* it is not required anymore */
#endif

Regards,
  Vincent