From ef246a1480cc484cd2aeda75737cb0848616ddf3 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 20 Sep 2023 21:25:26 +0300 Subject: wifi: mac80211: support antenna control in injection Support antenna control for injection by parsing the antenna radiotap field (which may be presented multiple times) and telling the driver about the resulting antenna bitmap. Of course there's no guarantee the driver will actually honour this, just like any other injection control. If misconfigured, i.e. the injected HT/VHT MCS needs more chains than antennas are configured, the bitmap is reset to zero, indicating no selection. For now this is only set up for two anntenas so we keep more free bits, but that can be trivially extended if any driver implements support for it that can deal with hardware with more antennas. Signed-off-by: Johannes Berg Signed-off-by: Gregory Greenman Link: https://lore.kernel.org/r/20230920211508.f71001aa4da9.I00ccb762a806ea62bc3d728fa3a0d29f4f285eeb@changeid Signed-off-by: Johannes Berg --- include/linux/ieee80211.h | 2 ++ include/net/mac80211.h | 6 +++++- net/mac80211/tx.c | 14 ++++++++++++++ 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index f2965ff3d7c1..3b02f038d509 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -1705,6 +1705,8 @@ struct ieee80211_mcs_info { #define IEEE80211_HT_MCS_TX_MAX_STREAMS 4 #define IEEE80211_HT_MCS_TX_UNEQUAL_MODULATION 0x10 +#define IEEE80211_HT_MCS_CHAINS(mcs) ((mcs) == 32 ? 1 : (1 + ((mcs) >> 3))) + /* * 802.11n D5.0 20.3.5 / 20.6 says: * - indices 0 to 7 and 32 are single spatial stream diff --git a/include/net/mac80211.h b/include/net/mac80211.h index d4ef2a605cb4..72375eceb786 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1178,7 +1178,11 @@ struct ieee80211_tx_info { u8 use_cts_prot:1; u8 short_preamble:1; u8 skip_table:1; - /* 2 bytes free */ + + /* for injection only (bitmap) */ + u8 antennas:2; + + /* 14 bits free */ }; /* only needed before rate control */ unsigned long jiffies; diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 932516f8cc13..a984fc54644e 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2162,6 +2162,11 @@ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb, rate_found = true; break; + case IEEE80211_RADIOTAP_ANTENNA: + /* this can appear multiple times, keep a bitmap */ + info->control.antennas |= BIT(*iterator.this_arg); + break; + case IEEE80211_RADIOTAP_DATA_RETRIES: rate_retries = *iterator.this_arg; break; @@ -2256,8 +2261,17 @@ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb, } if (rate_flags & IEEE80211_TX_RC_MCS) { + /* reset antennas if not enough */ + if (IEEE80211_HT_MCS_CHAINS(rate) > + hweight8(info->control.antennas)) + info->control.antennas = 0; + info->control.rates[0].idx = rate; } else if (rate_flags & IEEE80211_TX_RC_VHT_MCS) { + /* reset antennas if not enough */ + if (vht_nss > hweight8(info->control.antennas)) + info->control.antennas = 0; + ieee80211_rate_set_vht(info->control.rates, vht_mcs, vht_nss); } else if (sband) { -- cgit v1.2.3-70-g09d2