On 2016-10-13 07:41, Michael Braun wrote:
> According to IEEE 802.11-2012 section 8.3.2 table 8-19, the outer SA/DA
> of A-MSDU frames need to be changed depending on FromDS/ToDS values.
>
> Signed-off-by: Michael Braun <michael-dev@xxxxxxxxxxxxx>
>
> --
> v4:
> - h_80211_src/dst has been memmove'd and thus needs to be fixed
> v3:
> - write to outer 802.11 header instead of inner amsdu subframe header
> v2:
> - avoid the extra write to amsdu_hdr
> - avoid copy of asmdu_hdr into skb, use ptr instead
> ---
> net/mac80211/tx.c | 46 ++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 36 insertions(+), 10 deletions(-)
>
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index 5023966..5f80b94 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -3058,19 +3059,44 @@ static bool ieee80211_amsdu_prepare_head(struct ieee80211_sub_if_data *sdata,
> if (info->control.flags & IEEE80211_TX_CTRL_AMSDU)
> return true;
>
> - if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(amsdu_hdr),
> + if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(*amsdu_hdr),
> &subframe_len))
> return false;
>
> - amsdu_hdr.h_proto = cpu_to_be16(subframe_len);
> - memcpy(amsdu_hdr.h_source, skb->data + fast_tx->sa_offs, ETH_ALEN);
> - memcpy(amsdu_hdr.h_dest, skb->data + fast_tx->da_offs, ETH_ALEN);
> + data = skb_push(skb, sizeof(*amsdu_hdr));
> + memmove(data, data + sizeof(*amsdu_hdr), hdr_len);
> + hdr = data;
> + amsdu_hdr = data + hdr_len;
> + /* h_80211_src/dst is addr* field within hdr */
> + h_80211_src = data + fast_tx->sa_offs;
> + h_80211_dst = data + fast_tx->da_offs;
> +
> + amsdu_hdr->h_proto = cpu_to_be16(subframe_len);
> + memcpy(amsdu_hdr->h_source, h_80211_src, ETH_ALEN);
> + memcpy(amsdu_hdr->h_dest, h_80211_dst, ETH_ALEN);
> +
> + /* according to IEEE 802.11-2012 8.3.2 table 8-19, the outer SA/DA
> + * fields needs to be changed to BSSID for A-MSDU frames depending
> + * on FromDS/ToDS values.
> + */
> + switch (sdata->vif.type) {
> + case NL80211_IFTYPE_STATION:
> + bssid = sdata->u.mgd.bssid;
> + break;
> + case NL80211_IFTYPE_AP:
> + case NL80211_IFTYPE_AP_VLAN:
> + bssid = sdata->vif.addr;
> + break;
> + default:
> + bssid = NULL;
> + }
>
> - data = skb_push(skb, sizeof(amsdu_hdr));
> - memmove(data, data + sizeof(amsdu_hdr), hdr_len);
> - memcpy(data + hdr_len, &amsdu_hdr, sizeof(amsdu_hdr));
> + if (bssid && ieee80211_has_fromds(hdr->frame_control))
> + memcpy(h_80211_src, bssid, ETH_ALEN);
> +
> + if (bssid && ieee80211_has_tods(hdr->frame_control))
> + memcpy(h_80211_dst, bssid, ETH_ALEN);
I think this is probably wrong for 4-addr, since there both FromDS and
ToDS are set. Maybe you should use !ieee80211_has_tods instead of
ieee80211_has_fromds and vice versa.
- Felix
