From 72abd81b980ef7ffb83ecb4ac4a7627d9d575f50 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 17 Sep 2007 01:29:22 -0400 Subject: [PATCH] [MAC80211]: allow drivers to indicate failed FCS/PLCP checksum This patch allows drivers to indicate bad FCS/PLCP CRC to the stack and have the stack drop packets like that except for monitor interfaces. Signed-off-by: Johannes Berg Signed-off-by: Michael Wu Signed-off-by: John W. Linville Signed-off-by: David S. Miller --- include/net/mac80211.h | 6 ++++++ net/mac80211/rx.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 947f3c820e..7d9dc20ee4 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -235,6 +235,10 @@ struct ieee80211_tx_control { * @RX_FLAG_IV_STRIPPED: The IV/ICV are stripped from this frame. * If this flag is set, the stack cannot do any replay detection * hence the driver or hardware will have to do that. + * @RX_FLAG_FAILED_FCS_CRC: Set this flag if the FCS check failed on + * the frame. + * @RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on + * the frame. */ enum mac80211_rx_flags { RX_FLAG_MMIC_ERROR = 1<<0, @@ -242,6 +246,8 @@ enum mac80211_rx_flags { RX_FLAG_RADIOTAP = 1<<2, RX_FLAG_MMIC_STRIPPED = 1<<3, RX_FLAG_IV_STRIPPED = 1<<4, + RX_FLAG_FAILED_FCS_CRC = 1<<5, + RX_FLAG_FAILED_PLCP_CRC = 1<<6, }; /** diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index e9dcc6229c..cf2a72f89d 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -145,6 +145,8 @@ ieee80211_rx_monitor(struct net_device *dev, struct sk_buff *skb, __le16 chan_freq; __le16 chan_flags; u8 antsignal; + u8 padding_for_rxflags; + __le16 rx_flags; } __attribute__ ((packed)) *rthdr; skb->dev = dev; @@ -167,12 +169,21 @@ ieee80211_rx_monitor(struct net_device *dev, struct sk_buff *skb, cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) | (1 << IEEE80211_RADIOTAP_RATE) | (1 << IEEE80211_RADIOTAP_CHANNEL) | - (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL)); + (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) | + (1 << IEEE80211_RADIOTAP_RX_FLAGS)); rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ? IEEE80211_RADIOTAP_F_FCS : 0; + + /* FIXME: when radiotap gets a 'bad PLCP' flag use it here */ + rthdr->rx_flags = 0; + if (status->flag & + (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC)) + rthdr->rx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS); + rate = ieee80211_get_rate(local, status->phymode, status->rate); if (rate) rthdr->rate = rate->rate / 5; + rthdr->chan_freq = cpu_to_le16(status->freq); rthdr->chan_flags = status->phymode == MODE_IEEE80211A ? @@ -200,6 +211,15 @@ ieee80211_rx_h_monitor(struct ieee80211_txrx_data *rx) return TXRX_QUEUED; } + /* + * Drop frames with failed FCS/PLCP checksums here, they are only + * relevant for monitor mode, the rest of the stack should never + * see them. + */ + if (rx->u.rx.status->flag & + (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC)) + return TXRX_DROP; + if (rx->u.rx.status->flag & RX_FLAG_RADIOTAP) skb_pull(rx->skb, ieee80211_get_radiotap_len(rx->skb->data)); @@ -1360,6 +1380,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, struct ieee80211_sub_if_data *prev = NULL; struct sk_buff *skb_new; u8 *bssid; + int bogon; if (status->flag & RX_FLAG_RADIOTAP) { radiotap_len = ieee80211_get_radiotap_len(skb->data); @@ -1380,10 +1401,15 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, rx.u.rx.status = status; rx.fc = skb->len >= 2 ? le16_to_cpu(hdr->frame_control) : 0; type = rx.fc & IEEE80211_FCTL_FTYPE; - if (type == IEEE80211_FTYPE_DATA || type == IEEE80211_FTYPE_MGMT) + + bogon = status->flag & (RX_FLAG_FAILED_FCS_CRC | + RX_FLAG_FAILED_PLCP_CRC); + + if (!bogon && (type == IEEE80211_FTYPE_DATA || + type == IEEE80211_FTYPE_MGMT)) local->dot11ReceivedFragmentCount++; - if (skb->len >= 16) { + if (!bogon && skb->len >= 16) { sta = rx.sta = sta_info_get(local, hdr->addr2); if (sta) { rx.dev = rx.sta->dev; -- 2.39.5