On Sat, May 1, 2010 at 10:13 AM, Johannes Berg
<johannes@xxxxxxxxxxxxxxxx> wrote:
> This allows drivers to add radiotap vendor data
> to any received frame, which will be simply
> passed into userspace and ignored by the kernel.
> Can be used by drivers to convey hw-specific
> information.
Thanks a lot for all your work on this area, on the standardization
part, mac80211 and even for providing a simple example, its really
appreciated! Some comments below.
> Note: 11n shouldn't be done there, in case somebody
> got ideas!!
Well you mean 802.11n standard stuff, I take it, because there are
vendor 802.11n specific stuff.
> Note: didn't test this after the paged RX changes
> ---
> drivers/net/wireless/mac80211_hwsim.c | 17 ++++++++++
> include/net/mac80211.h | 12 +++++++
> net/mac80211/rx.c | 53 ++++++++++++++++++++++++++++++----
> 3 files changed, 77 insertions(+), 5 deletions(-)
>
> --- wireless-testing.orig/include/net/mac80211.h 2010-05-01 08:46:26.000000000 +0200
> +++ wireless-testing/include/net/mac80211.h 2010-05-01 08:47:54.000000000 +0200
> @@ -565,6 +565,13 @@ enum mac80211_rx_flags {
> * @rate_idx: index of data rate into band's supported rates or MCS index if
> * HT rates are use (RX_FLAG_HT)
> * @flag: %RX_FLAG_*
> + * @vendor_radiotap_bitmap: radiotap vendor namespace presence bitmap
> + * @vendor_radiotap_len: radiotap vendor namespace length
> + * @vendor_radiotap_align: radiotap vendor namespace alignment. Note
> + * that the actual data must be at the start of the SKB data
> + * already.
I see your WARN_ON() on the alignment being set to 0 and set it to 1
then. Can you clarify a little more on this here. If there is no
strict alignment requirements why not just treat 0 as 1 then?
> + * @vendor_radiotap_oui: radiotap vendor namespace OUI
> + * @vendor_radiotap_subns: radiotap vendor sub namespace
> */
> struct ieee80211_rx_status {
> u64 mactime;
> @@ -575,6 +582,11 @@ struct ieee80211_rx_status {
> int antenna;
> int rate_idx;
> int flag;
> + u32 vendor_radiotap_bitmap;
> + u16 vendor_radiotap_len;
> + u8 vendor_radiotap_align;
> + u8 vendor_radiotap_oui[3];
> + u8 vendor_radiotap_subns;
> };
>
> /**
> --- wireless-testing.orig/net/mac80211/rx.c 2010-05-01 08:46:26.000000000 +0200
> +++ wireless-testing/net/mac80211/rx.c 2010-05-01 08:47:54.000000000 +0200
> @@ -37,6 +37,8 @@
> static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
> struct sk_buff *skb)
> {
> + struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
> +
> if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
> if (likely(skb->len > FCS_LEN))
> __pskb_trim(skb, skb->len - FCS_LEN);
> @@ -48,6 +50,9 @@ static struct sk_buff *remove_monitor_in
> }
> }
>
> + if (status->vendor_radiotap_len)
> + __pskb_pull(skb, status->vendor_radiotap_len);
> +
> return skb;
> }
>
> @@ -69,8 +74,8 @@ static inline int should_drop_frame(stru
> }
>
> static int
> -ieee80211_rx_radiotap_len(struct ieee80211_local *local,
> - struct ieee80211_rx_status *status)
> +ieee80211_rx_radiotap_space(struct ieee80211_local *local,
> + struct ieee80211_rx_status *status)
> {
> int len;
>
> @@ -87,6 +92,21 @@ ieee80211_rx_radiotap_len(struct ieee802
> if (len & 1) /* padding for RX_FLAGS if necessary */
> len++;
>
> + if (status->vendor_radiotap_len) {
> + /* allocate extra bitmap */
> + len += 4;
> +
> + if (WARN_ON(status->vendor_radiotap_align == 0))
> + status->vendor_radiotap_align = 1;
> + /* align standard part of vendor namespace */
> + len = ALIGN(len, 2);
> + /* allocate standard part of vendor namespace */
> + len += 6;
> + /* align vendor-defined part */
> + len = ALIGN(len, status->vendor_radiotap_align);
> + /* vendor-defined part is already in skb */
> + }
> +
> return len;
> }
>
> @@ -115,10 +135,18 @@ ieee80211_add_rx_radiotap_header(struct
> (1 << IEEE80211_RADIOTAP_CHANNEL) |
> (1 << IEEE80211_RADIOTAP_ANTENNA) |
> (1 << IEEE80211_RADIOTAP_RX_FLAGS));
> - rthdr->it_len = cpu_to_le16(rtap_len);
> + rthdr->it_len = cpu_to_le16(rtap_len + status->vendor_radiotap_len);
>
> pos = (unsigned char *)(rthdr+1);
>
> + if (status->vendor_radiotap_len) {
> + rthdr->it_present |=
> + cpu_to_le32(BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE)) |
> + cpu_to_le32(BIT(IEEE80211_RADIOTAP_EXT));
> + put_unaligned_le32(status->vendor_radiotap_bitmap, pos);
> + pos += 4;
> + }
> +
> /* the order of the following fields is important */
>
> /* IEEE80211_RADIOTAP_TSFT */
> @@ -190,11 +218,26 @@ ieee80211_add_rx_radiotap_header(struct
> /* IEEE80211_RADIOTAP_RX_FLAGS */
> /* ensure 2 byte alignment for the 2 byte field as required */
> if ((pos - (u8 *)rthdr) & 1)
> - pos++;
> + *pos++ = 0;
Why is this needed though? We already memset(rthdr, 0, rtap_len); above.
> if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
> rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
> put_unaligned_le16(rx_flags, pos);
> pos += 2;
> +
> + if (status->vendor_radiotap_len) {
> + /* ensure 2 byte alignment for the vendor field as required */
> + if ((pos - (u8 *)rthdr) & 1)
> + *pos++ = 0;
> + *pos++ = status->vendor_radiotap_oui[0];
> + *pos++ = status->vendor_radiotap_oui[1];
> + *pos++ = status->vendor_radiotap_oui[2];
> + *pos++ = status->vendor_radiotap_subns;
> + put_unaligned_le16(status->vendor_radiotap_len, pos);
> + pos += 2;
> + /* align the actual payload as requested */
> + while ((pos - (u8 *)rthdr) & (status->vendor_radiotap_align - 1))
> + *pos++ = 0;
> + }
> }
>
> /*
> @@ -223,7 +266,7 @@ ieee80211_rx_monitor(struct ieee80211_lo
> */
>
> /* room for the radiotap header based on driver features */
> - needed_headroom = ieee80211_rx_radiotap_len(local, status);
> + needed_headroom = ieee80211_rx_radiotap_space(local, status);
>
> if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
> present_fcs_len = FCS_LEN;
> --- wireless-testing.orig/drivers/net/wireless/mac80211_hwsim.c 2010-05-01 08:46:27.000000000 +0200
> +++ wireless-testing/drivers/net/wireless/mac80211_hwsim.c 2010-05-01 19:04:57.000000000 +0200
> @@ -484,6 +484,7 @@ static bool mac80211_hwsim_tx_frame(stru
> struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
> struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
> struct ieee80211_rx_status rx_status;
> + u8 *vendor_data;
>
> if (data->idle) {
> printk(KERN_DEBUG "%s: Trying to TX when idle - reject\n",
> @@ -509,6 +510,20 @@ static bool mac80211_hwsim_tx_frame(stru
> secpath_reset(skb);
> nf_reset(skb);
>
> + vendor_data = skb_push(skb, 4);
> + rx_status.vendor_radiotap_len = 4;
> + rx_status.vendor_radiotap_align = 4;
> + rx_status.vendor_radiotap_oui[0] = 0xff;
> + rx_status.vendor_radiotap_oui[1] = 0xff;
> + rx_status.vendor_radiotap_oui[2] = 0xff;
> + rx_status.vendor_radiotap_subns = 129;
> + rx_status.vendor_radiotap_bitmap = 0x1;
> +
> + *vendor_data++ = 1;
> + *vendor_data++ = 2;
> + *vendor_data++ = 3;
> + *vendor_data++ = 4;
> +
Heh nice, now we just need a sample radiotap vendor extension parser example.
Thanks!!!
Luis
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