On Wednesday 14 March 2007 21:13, Andy Green wrote: > This patch adds the monitor mode packet injection stuff that was talked > about a week or so ago to mac80211. Using a radiotap header prepended > to the injection payload was felt to be a reasonable way forward. > It seems rather odd to inject with radiotap headers when capturing with AVS headers. I've attached a patch which switches mac80211 to using radiotap. It's pretty much the same patch I posted a while ago, except all support for AVS on monitor interfaces was removed. Drivers need to implement radiotap for best results, but if it isn't implemented, the stack fills in a minimal radiotap header. The minimal radiotap header filling code is new in this version of the patch and I haven't had a chance to test it yet. The rate filling part might be wrong. Anyway, I recommend basing your patch on top of this one. Aside from the new default radiotap filling code, the rest is fairly solid AFAIK. I had a corresponding patch to hook up radiotap support in zd1211rw-mac80211 but it seems like I've lost it. I'll put together a new one tomorrow. Thanks, -Michael Wu
mac80211: Add radiotap support
From: Michael Wu <flamingice@xxxxxxxxxxxx>
---
include/net/mac80211.h | 3 ++
net/mac80211/ieee80211.c | 69 +++++++++++++++++++++++++++++++++-------
net/mac80211/ieee80211_iface.c | 2 +
3 files changed, 61 insertions(+), 13 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 916b21b..050f126 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -529,6 +529,9 @@ struct ieee80211_hw {
* per-packet RC4 key with each TX frame when doing hwcrypto */
#define IEEE80211_HW_TKIP_REQ_PHASE2_KEY (1<<14)
+ /* Driver supports radiotap. Temporary until all drivers support it. */
+#define IEEE80211_HW_RADIOTAP_SUPPORTED (1<<20)
+
u32 flags; /* hardware flags defined above */
/* Set to the size of a needed device specific skb headroom for TX skbs. */
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 0b7cb35..c3a9f0e 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -8,6 +8,7 @@
*/
#include <net/mac80211.h>
+#include <net/ieee80211_radiotap.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
@@ -286,6 +287,14 @@ int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
+static int ieee80211_get_radiotap_len(struct sk_buff *skb)
+{
+ struct ieee80211_radiotap_header *hdr =
+ (struct ieee80211_radiotap_header *) skb->data;
+
+ return le16_to_cpu(hdr->it_len);
+}
+
#ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP
static void ieee80211_dump_frame(const char *ifname, const char *title,
const struct sk_buff *skb)
@@ -2741,26 +2750,50 @@ ieee80211_rx_monitor(struct net_device *dev, struct sk_buff *skb,
struct ieee80211_rx_status *status)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
- struct ieee80211_frame_info *fi;
struct ieee80211_sub_if_data *sdata;
- const size_t hlen = sizeof(struct ieee80211_frame_info)
- - sizeof(fi->msg_type);
+ struct ieee80211_rtap_hdr {
+ struct ieee80211_radiotap_header hdr;
+ u8 flags;
+ u8 pad0;
+ u8 rate;
+ u8 pad1;
+ __le16 chan_freq;
+ __le16 chan_flags;
+ u8 antsignal;
+ } __attribute__ ((packed)) *rthdr;
skb->dev = dev;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
- if (skb_headroom(skb) < hlen) {
- I802_DEBUG_INC(local->rx_expand_skb_head);
- if (pskb_expand_head(skb, hlen, 0, GFP_ATOMIC)) {
- dev_kfree_skb(skb);
- return;
+ if (!(local->hw.flags & IEEE80211_HW_RADIOTAP_SUPPORTED)) {
+ if (skb_headroom(skb) < sizeof(*rthdr)) {
+ I802_DEBUG_INC(local->rx_expand_skb_head);
+ if (pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC)) {
+ dev_kfree_skb(skb);
+ return;
+ }
}
- }
- fi = (struct ieee80211_frame_info *) skb_push(skb, hlen);
+ rthdr = (struct ieee80211_rtap_hdr *) skb_push(skb, sizeof(*rthdr));
+ memset(rthdr, 0, sizeof(*rthdr));
+ rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
+ rthdr->hdr.it_present =
+ cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) ||
+ (1 << IEEE80211_RADIOTAP_RATE) ||
+ (1 << IEEE80211_RADIOTAP_CHANNEL) ||
+ (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL));
+ rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
+ IEEE80211_RADIOTAP_F_FCS : 0;
+ rthdr->rate = status->rate / 5;
+ rthdr->chan_freq = cpu_to_le16(status->freq);
+ rthdr->chan_flags =
+ status->phymode == MODE_IEEE80211A ?
+ cpu_to_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ) :
+ cpu_to_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ);
+ rthdr->antsignal = status->ssi;
+ }
- ieee80211_fill_frame_info(local, fi, status);
sdata->stats.rx_packets++;
sdata->stats.rx_bytes += skb->len;
@@ -3164,6 +3197,10 @@ ieee80211_rx_h_monitor(struct ieee80211_txrx_data *rx)
return TXRX_QUEUED;
}
+ if (rx->local->monitors &&
+ rx->local->hw.flags & IEEE80211_HW_RADIOTAP_SUPPORTED)
+ skb_pull(rx->skb, ieee80211_get_radiotap_len(rx->skb));
+
return TXRX_CONTINUE;
}
@@ -3731,6 +3768,13 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
struct ieee80211_txrx_data rx;
u16 type;
int multicast;
+ int radiotap_len = 0;
+
+ if (local->monitors &&
+ local->hw.flags & IEEE80211_HW_RADIOTAP_SUPPORTED) {
+ radiotap_len = ieee80211_get_radiotap_len(skb);
+ skb_pull(skb, radiotap_len);
+ }
hdr = (struct ieee80211_hdr *) skb->data;
memset(&rx, 0, sizeof(rx));
@@ -3767,6 +3811,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
goto end;
skb = rx.skb;
+ skb_push(skb, radiotap_len);
if (sta && !sta->assoc_ap && !(sta->flags & WLAN_STA_WDS) &&
!local->iff_promiscs && !multicast) {
rx.u.rx.ra_match = 1;
@@ -3775,7 +3820,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
} else {
struct ieee80211_sub_if_data *prev = NULL;
struct sk_buff *skb_new;
- u8 *bssid = ieee80211_get_bssid(hdr, skb->len);
+ u8 *bssid = ieee80211_get_bssid(hdr, skb->len - radiotap_len);
list_for_each_entry(sdata, &local->sub_if_list, list) {
rx.u.rx.ra_match = 1;
diff --git a/net/mac80211/ieee80211_iface.c b/net/mac80211/ieee80211_iface.c
index 3e0b4fa..51197b1 100644
--- a/net/mac80211/ieee80211_iface.c
+++ b/net/mac80211/ieee80211_iface.c
@@ -199,7 +199,7 @@ void ieee80211_if_set_type(struct net_device *dev, int type)
break;
}
case IEEE80211_IF_TYPE_MNTR:
- dev->type = ARPHRD_IEEE80211_PRISM;
+ dev->type = ARPHRD_IEEE80211_RADIOTAP;
break;
default:
printk(KERN_WARNING "%s: %s: Unknown interface type 0x%x",
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