Re: [PATCH RFC] brcmfmac: support deleting MBSS AP interfaces

On 1 June 2016 at 21:00, Arend van Spriel [off-list ref] wrote:

On 01-06-16 16:36, Rafał Miłecki wrote:

quoted

We already support adding extra (AP) interfaces so it also makes an
obvious sense to allow deleting them.

Adding a new interface is implemented by sending request to firmware for
creating a new BSS and waiting for a proper event. Ideally deleting
interface should be handled in a similar way. There should be a request
to firmware for deleting BSS and firmware should respond with an event.

Unfortunately it doesn't seem to work with recent firmwares. They never
seem to delete BSS and never send BRCMF_E_IF_DEL. As a workaround this
patch deletes Linux interface while keeping a track of BSSes present in
a firmware. If there is request for adding a new interface this code is
capable of reusing existing BSS-es.

It is not so much an issue of recent firmware. Actually, on recent
firmware 7.x.y.z and higher there are other command to create *and*
delete additional interfaces. On the other hand we aim to support a
large number of devices going back to bcm4329 so we have to come up with
a scheme to use the new commands or fallback to old api. Let's hope we
can reuse much of this effort you put in.

You gave me a complex puzzle there :D It took me a while to find out
what API you meant.

Finally I found an interesting wlioctl.h in SDK 9.10.178.27 that gave
me some clue. I got this SDK from ASUS RT-AC1200G+ open souce tarball.
There are 2 interesting structs:

typedef struct wl_interface_create {
        uint16 ver; /* version of this struct */
        uint32  flags; /* flags that defines the operation */
        struct ether_addr   mac_addr; /* Optional Mac address */
        uint32  wlc_index; /* Optional wlc index */
} wl_interface_create_t;

typedef struct wl_interface_info {
        uint16 ver; /* version of this struct */
        struct ether_addr    mac_addr; /* MAC address of the interface */
        char ifname[BCM_MSG_IFNAME_MAX]; /* name of interface */
        uint8 bsscfgidx; /* source bsscfg index */
} wl_interface_info_t;

I couldn't find any corresponding WLC_* in wlioctl_defs.h, so I guess
I should use WLC_SET_VAR (or WLC_SET_VAR as you prefer) with some
string. Any tip what would it be? Something like
"wl_interface_create"? Can you reveal such a small secret?

Also can you share any tip on removing interface? I don't see any
struct for that. Is that handled by some special value in
"wl_interface_create_t" or by separated string used with WLC_SET_VAR?