[PATCH V2 2/3] brcmfmac: handle monitor mode marked msgbuf packets

["Rafał Miłecki" <zajec5@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

New Broadcom firmwares mark monitor mode packets using a newly defined
bit in the flags field. Use it to filter them out and pass to the
monitor interface. These defines were found in bcmmsgbuf.h from SDK.

As not every firmware generates radiotap header this commit introduces
BRCMF_FEAT_MON_FMT_RADIOTAP that has to be set per firmware version. If
not present brcmf_netif_mon_rx() assumed packet being a raw 802.11 frame
and prepends it with an empty radiotap header.

It's limited to the msgbuf protocol. Adding support for SDIO/USB devices
will require some extra research.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
V2: Use cpu_to_le16 when setting it_len
---
 .../wireless/broadcom/brcm80211/brcmfmac/core.c    | 24 ++++++++++++++++++++++
 .../wireless/broadcom/brcm80211/brcmfmac/core.h    |  2 ++
 .../wireless/broadcom/brcm80211/brcmfmac/feature.h |  6 +++++-
 .../wireless/broadcom/brcm80211/brcmfmac/msgbuf.c  | 17 +++++++++++++++
 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index 72954fd6df3b..c9e1f6fcc57b 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -21,6 +21,7 @@
 #include <net/cfg80211.h>
 #include <net/rtnetlink.h>
 #include <net/addrconf.h>
+#include <net/ieee80211_radiotap.h>
 #include <net/ipv6.h>
 #include <brcmu_utils.h>
 #include <brcmu_wifi.h>
@@ -404,6 +405,29 @@ void brcmf_netif_rx(struct brcmf_if *ifp, struct sk_buff *skb)
 		netif_rx_ni(skb);
 }
 
+void brcmf_netif_mon_rx(struct brcmf_if *ifp, struct sk_buff *skb)
+{
+	if (brcmf_feat_is_enabled(ifp, BRCMF_FEAT_MON_FMT_RADIOTAP)) {
+		/* Do nothing */
+	} else {
+		struct ieee80211_radiotap_header *radiotap;
+
+		radiotap = skb_push(skb, sizeof(*radiotap));
+		memset(radiotap, 0, sizeof(*radiotap));
+		radiotap->it_len = cpu_to_le16(sizeof(*radiotap));
+
+		/* TODO: what are these extra 4 bytes? */
+		skb->len -= 4;
+	}
+
+	skb->dev = ifp->ndev;
+	skb_reset_mac_header(skb);
+	skb->pkt_type = PACKET_OTHERHOST;
+	skb->protocol = htons(ETH_P_802_2);
+
+	brcmf_netif_rx(ifp, skb);
+}
+
 static int brcmf_rx_hdrpull(struct brcmf_pub *drvr, struct sk_buff *skb,
 			    struct brcmf_if **ifp)
 {
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
index 401f50458686..dcf6e27cc16f 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
@@ -121,6 +121,7 @@ struct brcmf_pub {
 
 	struct brcmf_if *iflist[BRCMF_MAX_IFS];
 	s32 if2bss[BRCMF_MAX_IFS];
+	struct brcmf_if *mon_if;
 
 	struct mutex proto_block;
 	unsigned char proto_buf[BRCMF_DCMD_MAXLEN];
@@ -216,6 +217,7 @@ void brcmf_txflowblock_if(struct brcmf_if *ifp,
 			  enum brcmf_netif_stop_reason reason, bool state);
 void brcmf_txfinalize(struct brcmf_if *ifp, struct sk_buff *txp, bool success);
 void brcmf_netif_rx(struct brcmf_if *ifp, struct sk_buff *skb);
+void brcmf_netif_mon_rx(struct brcmf_if *ifp, struct sk_buff *skb);
 void brcmf_net_setcarrier(struct brcmf_if *ifp, bool on);
 int __init brcmf_core_init(void);
 void __exit brcmf_core_exit(void);
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.h
index d1193825e559..6e417d104b7f 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/feature.h
@@ -33,6 +33,8 @@
  * MFP: 802.11w Management Frame Protection.
  * GSCAN: enhanced scan offload feature.
  * FWSUP: Firmware supplicant.
+ * MON_802_11_FLAG: monitor packets flagged as 802.11
+ * MON_FMT_RADIOTAP: monitor packets include radiotap header
  */
 #define BRCMF_FEAT_LIST \
 	BRCMF_FEAT_DEF(MBSS) \
@@ -48,7 +50,9 @@
 	BRCMF_FEAT_DEF(WOWL_ARP_ND) \
 	BRCMF_FEAT_DEF(MFP) \
 	BRCMF_FEAT_DEF(GSCAN) \
-	BRCMF_FEAT_DEF(FWSUP)
+	BRCMF_FEAT_DEF(FWSUP) \
+	BRCMF_FEAT_DEF(MON_802_11_FLAG) \
+	BRCMF_FEAT_DEF(MON_FMT_RADIOTAP)
 
 /*
  * Quirks:
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
index 49d37ad96958..47a9318cccb8 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/msgbuf.c
@@ -69,6 +69,8 @@
 #define BRCMF_MSGBUF_MAX_EVENTBUF_POST		8
 
 #define BRCMF_MSGBUF_PKT_FLAGS_FRAME_802_3	0x01
+#define BRCMF_MSGBUF_PKT_FLAGS_FRAME_802_11	0x02
+#define BRCMF_MSGBUF_PKT_FLAGS_FRAME_MASK	0x07
 #define BRCMF_MSGBUF_PKT_FLAGS_PRIO_SHIFT	5
 
 #define BRCMF_MSGBUF_TX_FLUSH_CNT1		32
@@ -1128,6 +1130,7 @@ brcmf_msgbuf_process_rx_complete(struct brcmf_msgbuf *msgbuf, void *buf)
 	struct sk_buff *skb;
 	u16 data_offset;
 	u16 buflen;
+	u16 flags;
 	u32 idx;
 	struct brcmf_if *ifp;
 
@@ -1137,6 +1140,7 @@ brcmf_msgbuf_process_rx_complete(struct brcmf_msgbuf *msgbuf, void *buf)
 	data_offset = le16_to_cpu(rx_complete->data_offset);
 	buflen = le16_to_cpu(rx_complete->data_len);
 	idx = le32_to_cpu(rx_complete->msg.request_id);
+	flags = le16_to_cpu(rx_complete->flags);
 
 	skb = brcmf_msgbuf_get_pktid(msgbuf->drvr->bus_if->dev,
 				     msgbuf->rx_pktids, idx);
@@ -1150,6 +1154,19 @@ brcmf_msgbuf_process_rx_complete(struct brcmf_msgbuf *msgbuf, void *buf)
 
 	skb_trim(skb, buflen);
 
+	if ((flags & BRCMF_MSGBUF_PKT_FLAGS_FRAME_MASK) ==
+	    BRCMF_MSGBUF_PKT_FLAGS_FRAME_802_11) {
+		ifp = msgbuf->drvr->mon_if;
+
+		if (!ifp) {
+			brcmf_err("Received unexpected monitor pkt\n");
+			brcmu_pkt_buf_free_skb(skb);
+		}
+
+		brcmf_netif_mon_rx(ifp, skb);
+		return;
+	}
+
 	ifp = brcmf_get_ifp(msgbuf->drvr, rx_complete->msg.ifidx);
 	if (!ifp || !ifp->ndev) {
 		brcmf_err("Received pkt for invalid ifidx %d\n",
-- 
2.13.6