* [PATCH 1/5] mac80211:Change Radiotap to little-endian (Pavel Roskin)
2007-03-29 13:38 [PATCH 0/5] Try #6: Radiotap on Monitor Mode interfaces for rx and tx andy
@ 2007-03-29 13:38 ` andy
2007-03-29 13:38 ` [PATCH 2/5] mac80211: Add radiotap support for Monitor mode RX andy
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: andy @ 2007-03-29 13:38 UTC (permalink / raw)
To: linux-wireless; +Cc: Pavel Roskin
Meddled with by Andy Green since signed-off: made it apply to current
wireless-dev, took out comments for radiotap types not in current wireless-dev
Document that all fields must be little endian. Use annotated types
even in the comments. Consistently use shorter type names (u8, s8).
Realign the comments.
Signed-off-by: Pavel Roskin <proski@gnu.org>
diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index 429b738..7dbf9fb 100644
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -66,7 +66,9 @@
*/
#define IEEE80211_RADIOTAP_HDRLEN 64
-/* The radio capture header precedes the 802.11 header. */
+/* The radio capture header precedes the 802.11 header.
+ * All data in the header is little endian on all platforms.
+ */
struct ieee80211_radiotap_header {
u8 it_version; /* Version 0. Only increases
* for drastic changes,
@@ -74,12 +76,12 @@ struct ieee80211_radiotap_header {
* new fields does not count.
*/
u8 it_pad;
- u16 it_len; /* length of the whole
+ __le16 it_len; /* length of the whole
* header in bytes, including
* it_version, it_pad,
* it_len, and data fields.
*/
- u32 it_present; /* A bitmap telling which
+ __le32 it_present; /* A bitmap telling which
* fields are present. Set bit 31
* (0x80000000) to extend the
* bitmap by another 32 bits.
@@ -91,84 +93,84 @@ struct ieee80211_radiotap_header {
/* Name Data type Units
* ---- --------- -----
*
- * IEEE80211_RADIOTAP_TSFT u64 microseconds
+ * IEEE80211_RADIOTAP_TSFT __le64 microseconds
*
* Value in microseconds of the MAC's 64-bit 802.11 Time
* Synchronization Function timer when the first bit of the
* MPDU arrived at the MAC. For received frames, only.
*
- * IEEE80211_RADIOTAP_CHANNEL 2 x u16 MHz, bitmap
+ * IEEE80211_RADIOTAP_CHANNEL 2 x __le16 MHz, bitmap
*
* Tx/Rx frequency in MHz, followed by flags (see below).
*
- * IEEE80211_RADIOTAP_FHSS u16 see below
+ * IEEE80211_RADIOTAP_FHSS __le16 see below
*
* For frequency-hopping radios, the hop set (first byte)
* and pattern (second byte).
*
- * IEEE80211_RADIOTAP_RATE u8 500kb/s
+ * IEEE80211_RADIOTAP_RATE u8 500kb/s
*
* Tx/Rx data rate
*
- * IEEE80211_RADIOTAP_DBM_ANTSIGNAL int8_t decibels from
+ * IEEE80211_RADIOTAP_DBM_ANTSIGNAL s8 decibels from
* one milliwatt (dBm)
*
* RF signal power at the antenna, decibel difference from
* one milliwatt.
*
- * IEEE80211_RADIOTAP_DBM_ANTNOISE int8_t decibels from
+ * IEEE80211_RADIOTAP_DBM_ANTNOISE s8 decibels from
* one milliwatt (dBm)
*
* RF noise power at the antenna, decibel difference from one
* milliwatt.
*
- * IEEE80211_RADIOTAP_DB_ANTSIGNAL u8 decibel (dB)
+ * IEEE80211_RADIOTAP_DB_ANTSIGNAL u8 decibel (dB)
*
* RF signal power at the antenna, decibel difference from an
* arbitrary, fixed reference.
*
- * IEEE80211_RADIOTAP_DB_ANTNOISE u8 decibel (dB)
+ * IEEE80211_RADIOTAP_DB_ANTNOISE u8 decibel (dB)
*
* RF noise power at the antenna, decibel difference from an
* arbitrary, fixed reference point.
*
- * IEEE80211_RADIOTAP_LOCK_QUALITY u16 unitless
+ * IEEE80211_RADIOTAP_LOCK_QUALITY __le16 unitless
*
* Quality of Barker code lock. Unitless. Monotonically
* nondecreasing with "better" lock strength. Called "Signal
* Quality" in datasheets. (Is there a standard way to measure
* this?)
*
- * IEEE80211_RADIOTAP_TX_ATTENUATION u16 unitless
+ * IEEE80211_RADIOTAP_TX_ATTENUATION __le16 unitless
*
* Transmit power expressed as unitless distance from max
* power set at factory calibration. 0 is max power.
* Monotonically nondecreasing with lower power levels.
*
- * IEEE80211_RADIOTAP_DB_TX_ATTENUATION u16 decibels (dB)
+ * IEEE80211_RADIOTAP_DB_TX_ATTENUATION __le16 decibels (dB)
*
* Transmit power expressed as decibel distance from max power
* set at factory calibration. 0 is max power. Monotonically
* nondecreasing with lower power levels.
*
- * IEEE80211_RADIOTAP_DBM_TX_POWER int8_t decibels from
+ * IEEE80211_RADIOTAP_DBM_TX_POWER s8 decibels from
* one milliwatt (dBm)
*
* Transmit power expressed as dBm (decibels from a 1 milliwatt
* reference). This is the absolute power level measured at
* the antenna port.
*
- * IEEE80211_RADIOTAP_FLAGS u8 bitmap
+ * IEEE80211_RADIOTAP_FLAGS u8 bitmap
*
* Properties of transmitted and received frames. See flags
* defined below.
*
- * IEEE80211_RADIOTAP_ANTENNA u8 antenna index
+ * IEEE80211_RADIOTAP_ANTENNA u8 antenna index
*
* Unitless indication of the Rx/Tx antenna for this packet.
* The first antenna is antenna 0.
*
- * IEEE80211_RADIOTAP_FCS u32 data
+ * IEEE80211_RADIOTAP_FCS __le32 data
*
* FCS from frame in network byte order.
*/
--
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/5] mac80211: Add radiotap support for Monitor mode RX
2007-03-29 13:38 [PATCH 0/5] Try #6: Radiotap on Monitor Mode interfaces for rx and tx andy
2007-03-29 13:38 ` [PATCH 1/5] mac80211:Change Radiotap to little-endian (Pavel Roskin) andy
@ 2007-03-29 13:38 ` andy
2007-03-29 13:38 ` [PATCH 3/5] mac80211: Monitor mode radiotap injection docs andy
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: andy @ 2007-03-29 13:38 UTC (permalink / raw)
To: linux-wireless
Try #2
- Fix radiotap bitmap generation (Andy Green)
- Fix radiotap padding (Michael Wu)
From: Michael Wu <flamingice@sourmilk.net>
---
include/net/mac80211.h | 3 ++
net/mac80211/ieee80211.c | 67 +++++++++++++++++++++++++++++++++-------
net/mac80211/ieee80211_iface.c | 2 +
3 files changed, 59 insertions(+), 13 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 916b21b..27cffdc 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -518,6 +518,9 @@ struct ieee80211_hw {
* normal operation. */
#define IEEE80211_HW_MONITOR_DURING_OPER (1<<9)
+ /* Driver supports radiotap. */
+#define IEEE80211_HW_RADIOTAP_SUPPORTED (1<<10)
+
/* please fill this gap when adding new flags */
/* calculate Michael MIC for an MSDU when doing hwcrypto */
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 0b7cb35..6bffc29 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 +2750,48 @@ 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 rate;
+ __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 +3195,10 @@ 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 +3766,13 @@ 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 +3809,7 @@ 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 +3818,7 @@ 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",
--
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/5] mac80211: Monitor mode radiotap injection docs
2007-03-29 13:38 [PATCH 0/5] Try #6: Radiotap on Monitor Mode interfaces for rx and tx andy
2007-03-29 13:38 ` [PATCH 1/5] mac80211:Change Radiotap to little-endian (Pavel Roskin) andy
2007-03-29 13:38 ` [PATCH 2/5] mac80211: Add radiotap support for Monitor mode RX andy
@ 2007-03-29 13:38 ` andy
2007-03-29 13:38 ` [PATCH 4/5] cfg80211:Radiotap parser andy
2007-03-29 13:38 ` [PATCH 5/5] mac80211: Monitor mode radiotap-based packet injection andy
4 siblings, 0 replies; 6+ messages in thread
From: andy @ 2007-03-29 13:38 UTC (permalink / raw)
To: linux-wireless
From: Andy Green <andy@warmcat.com>
diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt
new file mode 100644
index 0000000..53ef7a0
--- /dev/null
+++ b/Documentation/networking/mac80211-injection.txt
@@ -0,0 +1,59 @@
+How to use packet injection with mac80211
+=========================================
+
+mac80211 now allows arbitrary packets to be injected down any Monitor Mode
+interface from userland. The packet you inject needs to be composed in the
+following format:
+
+ [ radiotap header ]
+ [ ieee80211 header ]
+ [ payload ]
+
+The radiotap format is discussed in
+./Documentation/networking/radiotap-headers.txt.
+
+Despite 13 radiotap argument types are currently defined, most only make sense
+to appear on received packets. Currently three kinds of argument are used by
+the injection code, although it knows to skip any other arguments that are
+present (facilitating replay of captured radiotap headers directly):
+
+ - IEEE80211_RADIOTAP_RATE - u8 arg in 500kbps units (0x02 --> 1Mbps)
+
+ - IEEE80211_RADIOTAP_ANTENNA - u8 arg, 0x00 = ant1, 0x01 = ant2
+
+ - IEEE80211_RADIOTAP_DBM_TX_POWER - u8 arg, dBm
+
+Here is an example valid radiotap header defining these three parameters
+
+ 0x00, 0x00, // <-- radiotap version
+ 0x0b, 0x00, // <- radiotap header length
+ 0x04, 0x0c, 0x00, 0x00, // <-- bitmap
+ 0x6c, // <-- rate
+ 0x0c, //<-- tx power
+ 0x01 //<-- antenna
+
+The ieee80211 header follows immediately afterwards, looking for example like
+this:
+
+ 0x08, 0x01, 0x00, 0x00,
+ 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+ 0x13, 0x22, 0x33, 0x44, 0x55, 0x66,
+ 0x13, 0x22, 0x33, 0x44, 0x55, 0x66,
+ 0x10, 0x86
+
+Then lastly there is the payload.
+
+After composing the packet contents, it is sent by send()-ing it to a logical
+mac80211 interface that is in Monitor mode. Libpcap can also be used,
+(which is easier than doing the work to bind the socket to the right
+interface), along the following lines:
+
+ ppcap = pcap_open_live(szInterfaceName, 800, 1, 20, szErrbuf);
+...
+ r = pcap_inject(ppcap, u8aSendBuffer, nLength);
+
+You can also find sources for a complete inject test applet here:
+
+http://penumbra.warmcat.com/_twk/tiki-index.php?page=packetspammer
+
+Andy Green <andy@warmcat.com>
diff --git a/Documentation/networking/radiotap-headers.txt b/Documentation/networking/radiotap-headers.txt
new file mode 100644
index 0000000..0d2207a
--- /dev/null
+++ b/Documentation/networking/radiotap-headers.txt
@@ -0,0 +1,79 @@
+How to use radiotap headers
+===========================
+
+Pointer to the radiotap include file
+------------------------------------
+
+Radiotap headers are variable-length and extensible, you can get most of the
+information you need to know on them from:
+
+./include/net/ieee80211_radiotap.h
+
+This document gives an overview and warns on some corner cases.
+
+
+Structure of the header
+-----------------------
+
+There is a fixed portion at the start which contains a u32 bitmap that defines
+if the possible argument associated with that bit is present or not. So if b0
+of the it_present member of ieee80211_radiotap_header is set, it means that
+the header for argument index 0 (IEEE80211_RADIOTAP_TSFT) is present in the
+argument area.
+
+ < 8-byte ieee80211_radiotap_header >
+ [ <possible argument bitmap extensions ... > ]
+ [ <argument> ... ]
+
+At the moment there are only 13 possible argument indexes defined, but in case
+we run out of space in the u32 it_present member, it is defined that b31 set
+indicates that there is another u32 bitmap following (shown as "possible
+argument bitmap extensions..." above), and the start of the arguments is moved
+forward 4 bytes each time.
+
+Note also that the it_len member __le16 is set to the total number of bytes
+covered by the ieee80211_radiotap_header and any arguments following.
+
+
+Requirements for arguments
+--------------------------
+
+After the fixed part of the header, the arguments follow for each argument
+index whose matching bit is set in the it_present member of
+ieee80211_radiotap_header.
+
+ - the arguments are all stored little-endian!
+
+ - the argument payload for a given argument index has a fixed size. So
+ IEEE80211_RADIOTAP_TSFT being present always indicates an 8-byte argument is
+ present. See the comments in ./include/net/ieee80211_radiotap.h for a nice
+ breakdown of all the argument sizes
+
+ - the arguments must be aligned to a boundary of the argument size using
+ padding. So a u16 argument must start on the next u16 boundary if it isn't
+ already on one, a u32 must start on the next u32 boundary and so on.
+
+ - "alignment" is relative to the start of the ieee80211_radiotap_header, ie,
+ the first byte of the radiotap header. The absolute alignment of that first
+ byte isn't defined. So even if the whole radiotap header is starting at, eg,
+ address 0x00000003, still the first byte of the radiotap header is treated as
+ 0 for alignment purposes.
+
+ - The arguments for a given argument index can be a compound of multiple types
+ together. For example IEEE80211_RADIOTAP_CHANNEL has an argument payload
+ consisting of two u16s of total length 4. When this happens, the padding
+ rule is applied dealing with a u16, NOT dealing with a 4-byte single entity.
+
+
+Example valid radiotap header
+-----------------------------
+
+ 0x00, 0x00, // <-- radiotap version + pad byte
+ 0x0b, 0x00, // <- radiotap header length
+ 0x04, 0x0c, 0x00, 0x00, // <-- bitmap
+ 0x6c, // <-- rate (in 500kHz units)
+ 0x0c, //<-- tx power
+ 0x01 //<-- antenna
+
+
+Andy Green <andy@warmcat.com>
--
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/5] cfg80211:Radiotap parser
2007-03-29 13:38 [PATCH 0/5] Try #6: Radiotap on Monitor Mode interfaces for rx and tx andy
` (2 preceding siblings ...)
2007-03-29 13:38 ` [PATCH 3/5] mac80211: Monitor mode radiotap injection docs andy
@ 2007-03-29 13:38 ` andy
2007-03-29 13:38 ` [PATCH 5/5] mac80211: Monitor mode radiotap-based packet injection andy
4 siblings, 0 replies; 6+ messages in thread
From: andy @ 2007-03-29 13:38 UTC (permalink / raw)
To: linux-wireless
From: Andy Green <andy@warmcat.com>
Try #1
- Based on Johannes Berg's comments, broke out the radiotap parsing into
its own file as part of cfg80211
- From same comments, added mask constant for b31 of arg presence bitfield
to ieee80211_radiotap.h
- Fixed subtle but nasty bug with alignment: args in the radiotap area are
aligned *relative to the start of the header* now. The header is not
guaranteed to align to anything (it is randomly in an skb data area).
===================================================
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 47e4544..098d4b6 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -74,6 +74,41 @@ struct key_params {
u32 cipher;
};
+
+/* Radiotap header iteration
+ * implemented in net/wireless/radiotap.c
+ *
+ * call __ieee80211_radiotap_iterator_init() to init the opaque iterator
+ * (no need to init anything in there beforehand)
+ * then loop calling __ieee80211_radiotap_iterator_next()... it returns -1
+ * if there are no more args in the header, or the next argument type index
+ * that is present. The iterator's this_arg member points to the start of the
+ * argument associated with the current argument type that is present,
+ * which can be found in the iterator's this_arg_index member.
+ */
+
+struct ieee80211_radiotap_iterator {
+ struct ieee80211_radiotap_header *rtheader;
+ int max_length; /* copy of max length we can scan over */
+ int this_arg_index; /* IEEE80211_RADIOTAP_* index for caller */
+ u8 * this_arg; /* current arg start position, caller can change */
+
+ int arg_index; /* internal: arg index b0 of bitmap_shifter represents */
+ u8 * arg; /* internal: points to the next arg start position */
+ __le32 *next_bitmap; /* internal */
+ u32 bitmap_shifter; /* internal */
+};
+
+extern int ieee80211_radiotap_iterator_init(
+ struct ieee80211_radiotap_iterator * iterator,
+ struct ieee80211_radiotap_header * radiotap_header,
+ int max_length
+);
+
+extern int ieee80211_radiotap_iterator_next(
+ struct ieee80211_radiotap_iterator * iterator);
+
+
/* from net/wireless.h */
struct wiphy;
diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index 7dbf9fb..b73c665 100644
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -59,6 +59,9 @@
* use sufficiently weaselly language ("is a monotonically nondecreasing
* function of...") that I cannot set false expectations for lawyerly
* readers.
+ *
+ * All arguments and fields in the struct at the start are
+ * Little-endian
*/
/* XXX tcpdump/libpcap do not tolerate variable-length headers,
@@ -90,6 +93,8 @@ struct ieee80211_radiotap_header {
*/
};
+#define IEEE80211_RADIOTAP_PRESENT_EXTEND_MASK 0x80000000
+
/* Name Data type Units
* ---- --------- -----
*
@@ -230,4 +235,7 @@ enum ieee80211_radiotap_type {
(((x) == 14) ? 2484 : ((x) * 5) + 2407) : \
((x) + 1000) * 5)
-#endif /* IEEE80211_RADIOTAP_H */
+#endif
+
+
+/* IEEE80211_RADIOTAP_H */
diff --git a/net/wireless/Makefile b/net/wireless/Makefile
index 507a028..26f815a 100644
--- a/net/wireless/Makefile
+++ b/net/wireless/Makefile
@@ -1,6 +1,6 @@
obj-$(CONFIG_CFG80211) += cfg80211.o
-cfg80211-y += core.o sysfs.o
+cfg80211-y += core.o sysfs.o radiotap.o
cfg80211-$(CONFIG_NL80211) += nl80211.o
cfg80211-$(CONFIG_CFG80211_WEXT_COMPAT) += wext-compat.o
diff --git a/net/wireless/radiotap.c b/net/wireless/radiotap.c
new file mode 100644
index 0000000..2275e8e
--- /dev/null
+++ b/net/wireless/radiotap.c
@@ -0,0 +1,213 @@
+/*
+ * Radiotap parser
+ *
+ * Copyright 2007 Andy Green <andy@warmcat.com>
+ */
+
+#include <linux/if.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <net/genetlink.h>
+#include <net/cfg80211.h>
+#include <net/wireless.h>
+#include "nl80211.h"
+#include "core.h"
+#include <net/ieee80211_radiotap.h>
+
+
+/**
+ * ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
+ * @iterator: radiotap_iterator to initialize
+ * @radiotap_header: radiotap header to parse
+ * @max_length: total length we can parse into (eg, whole packet length)
+ *
+ * Returns: 0 on success or negative if sanity check fails
+ *
+ * This function initializes an opaque iterator struct which can then
+ * be passed to ieee80211_radiotap_iterator_next() to visit every radiotap
+ * argument which is present in the header. It knows about extended
+ * present headers and handles them.
+ */
+
+int ieee80211_radiotap_iterator_init(
+ struct ieee80211_radiotap_iterator * iterator,
+ struct ieee80211_radiotap_header * radiotap_header,
+ int max_length)
+{
+
+ /* Linux only supports version 0 radiotap format */
+
+ if (radiotap_header->it_version)
+ return -EINVAL;
+
+ /* sanity check for allowed length and radiotap length field */
+
+ if (max_length < (le16_to_cpu(radiotap_header->it_len)))
+ return -EINVAL;
+
+ iterator->rtheader = radiotap_header;
+ iterator->max_length = le16_to_cpu(radiotap_header->it_len);
+ iterator->arg_index = 0;
+ iterator->bitmap_shifter = le32_to_cpu(radiotap_header->it_present);
+ iterator->arg = ((u8 *)radiotap_header) +
+ sizeof(struct ieee80211_radiotap_header);
+ iterator->this_arg = 0;
+
+ /* find payload start allowing for extended bitmap(s) */
+
+ if (iterator->bitmap_shifter & IEEE80211_RADIOTAP_PRESENT_EXTEND_MASK) {
+ while (le32_to_cpu(*((u32 *)iterator->arg)) &
+ IEEE80211_RADIOTAP_PRESENT_EXTEND_MASK)
+ iterator->arg += sizeof(u32);
+ iterator->arg += sizeof(u32);
+ }
+
+ /* we are all initialized happily */
+
+ return 0;
+}
+
+EXPORT_SYMBOL(ieee80211_radiotap_iterator_init);
+
+
+/**
+ * ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
+ * @iterator: radiotap_iterator to move to next arg (if any)
+ *
+ * Returns: next present arg index on success or negative if no more or error
+ *
+ * This function returns the next radiotap arg index (IEEE80211_RADIOTAP_*)
+ * and sets iterator->this_arg to point to the payload for the arg. It takes
+ * care of alignment handling and extended present fields. interator->this_arg
+ * can be changed by the caller. The args pointed to are in little-endian
+ * format.
+ */
+
+int ieee80211_radiotap_iterator_next(
+ struct ieee80211_radiotap_iterator * iterator)
+{
+
+ /* small length lookup table for all radiotap types we heard of
+ * starting from b0 in the bitmap, so we can walk the payload
+ * area of the radiotap header
+ *
+ * There is a requirement to pad args, so that args
+ * of a given length must begin at a boundary of that length
+ * -- but note that compound args are allowed (eg, 2 x u16
+ * for IEEE80211_RADIOTAP_CHANNEL) so total arg length is not
+ * a reliable indicator of alignment requirement.
+ *
+ * upper nybble: content alignment for arg
+ * lower nybble: content length for arg
+ */
+
+ static const u8 rt_sizes[] = {
+ [IEEE80211_RADIOTAP_TSFT] = 0x88,
+ [IEEE80211_RADIOTAP_FLAGS] = 0x11,
+ [IEEE80211_RADIOTAP_RATE] = 0x11,
+ [IEEE80211_RADIOTAP_CHANNEL] = 0x24,
+ [IEEE80211_RADIOTAP_FHSS] = 0x22,
+ [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = 0x11,
+ [IEEE80211_RADIOTAP_DBM_ANTNOISE] = 0x11,
+ [IEEE80211_RADIOTAP_LOCK_QUALITY] = 0x22,
+ [IEEE80211_RADIOTAP_TX_ATTENUATION] = 0x22,
+ [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = 0x22,
+ [IEEE80211_RADIOTAP_DBM_TX_POWER] = 0x11,
+ [IEEE80211_RADIOTAP_ANTENNA] = 0x11,
+ [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = 0x11,
+ [IEEE80211_RADIOTAP_DB_ANTNOISE] = 0x11
+ /* add more here as they are defined in
+ * include/net/ieee80211_radiotap.h
+ */
+ };
+
+ /* for every radiotap entry we can at
+ * least skip (by knowing the length)...
+ */
+
+ while (iterator->arg_index < sizeof(rt_sizes)) {
+ int hit=0;
+
+ if (!(iterator->bitmap_shifter & 1))
+ goto next_entry; /* arg not present */
+
+ /* arg is present, account for alignment padding
+ * 8-bit args can be at any alignment
+ * 16-bit args must start on 16-bit boundary
+ * 32-bit args must start on 32-bit boundary
+ * 64-bit args must start on 64-bit boundary
+ *
+ * note that total arg size can differ from alignment of
+ * elements inside arg, so we use upper nybble of length
+ * table to base alignment on
+ *
+ * also note: these alignments are ** relative to the
+ * start of the radiotap header **. There is no guarantee
+ * that the radiotap header itself is aligned on any
+ * kind of boundary.
+ */
+
+ if ((((int)iterator->arg)-((int)iterator->rtheader)) &
+ ((rt_sizes[iterator->arg_index] >> 4) - 1))
+ iterator->arg_index +=
+ (rt_sizes[iterator->arg_index] >> 4) -
+ ((((int)iterator->arg) -
+ ((int)iterator->rtheader)) &
+ ((rt_sizes[iterator->arg_index] >> 4) - 1));
+
+ /* this is what we will return to user, but we need to
+ * move on first so next call has something fresh to test
+ */
+
+ iterator->this_arg_index = iterator->arg_index;
+ iterator->this_arg = iterator->arg;
+ hit = 1;
+
+ /* internally move on the size of this arg */
+
+ iterator->arg += rt_sizes[iterator->arg_index] & 0x0f;
+
+ /* check for insanity where we are given a bitmap that
+ * claims to have more arg content than the length of the
+ * radiotap section. We will normally end up equalling this
+ * max_length on the last arg, never exceeding it.
+ */
+
+ if((((int)iterator->arg) - ((int)iterator->rtheader)) >
+ iterator->max_length)
+ return -EINVAL;
+
+ next_entry:
+
+ iterator->arg_index++;
+ if (unlikely((iterator->arg_index & 31) == 0)) {
+ /* completed current u32 bitmap */
+ if (iterator->bitmap_shifter & 1) {
+ /* b31 was set, there is more */
+ /* move to next u32 bitmap */
+ iterator->bitmap_shifter = le32_to_cpu(
+ *iterator->next_bitmap);
+ iterator->next_bitmap++;
+ } else {
+ /* no more bitmaps: end */
+ iterator->arg_index = sizeof(rt_sizes);
+ }
+ } else { /* just try the next bit */
+ iterator->bitmap_shifter >>= 1;
+ }
+
+ /* if we found a valid arg earlier, return it now */
+
+ if (hit)
+ return iterator->this_arg_index;
+
+ }
+
+ /* we don't know how to handle any more args, we're done */
+
+ return -1;
+}
+
+EXPORT_SYMBOL(ieee80211_radiotap_iterator_next);
+
--
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 5/5] mac80211: Monitor mode radiotap-based packet injection
2007-03-29 13:38 [PATCH 0/5] Try #6: Radiotap on Monitor Mode interfaces for rx and tx andy
` (3 preceding siblings ...)
2007-03-29 13:38 ` [PATCH 4/5] cfg80211:Radiotap parser andy
@ 2007-03-29 13:38 ` andy
4 siblings, 0 replies; 6+ messages in thread
From: andy @ 2007-03-29 13:38 UTC (permalink / raw)
To: linux-wireless
From: Andy Green <andy@warmcat.com>
Try #6
- Accounted for various comments from Johannes Berg
- Radiotap parsing is moved to cfg80211 as requested in a separate patch
Try #5
- De-indent last few indented comments
Try #4
- All from Michael Wu's feedback: further style heresies removed
- took account of radiotap arg alignment requirement. n-byte arg must be
placed on n-byte boundary using padding where necessary
Try #3
- moved to Michael Wu's method of tracking if we came in on a
monitor interface by using ifindex
- removed older proposed monitor interface tracking method and flags
- style fixes
- removed duped #include that is present in Michael Wu's patch already
Try #2
- took Michael Wu's advice about better tools and basing on wireless-dev
- took Luis Rodriguez's advice about coding style makeover
- took Pavel Roskin's advice about little-endian radiotap
===================================================
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index e6a0a0e..95b041e 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -1070,7 +1070,111 @@ ieee80211_tx_h_ps_buf(struct ieee80211_txrx_data *tx)
}
-static void inline
+/* deal with packet injection down monitor interface
+ * with Radiotap Header -- only called for monitor mode interface
+ */
+
+static ieee80211_txrx_result
+__ieee80211_convert_radiotap_to_control_and_remove(
+ struct ieee80211_txrx_data *tx,
+ struct sk_buff *skb, struct ieee80211_tx_control *control)
+{
+ /* this is the moment to interpret and discard the radiotap header that
+ * must be at the start of the packet injected in Monitor mode
+ *
+ * Need to take some care with endian-ness since radiotap
+ * args are little-endian
+ */
+
+ struct ieee80211_radiotap_iterator iterator;
+ struct ieee80211_radiotap_header *rthdr =
+ (struct ieee80211_radiotap_header *) skb->data;
+ struct ieee80211_hw_mode *hw_mode=tx->local->hw.conf.mode;
+
+ /* this can fail some sanity checks, drop packet if it does so */
+
+ if (ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len) < 0)
+ return TXRX_DROP;
+
+ /* default control situation for all injected packets
+ * FIXME: this does not suit all usage cases, expand to allow control
+ */
+
+ control->retry_limit = 1; /* no retry */
+ control->key_idx = -1; /* no encryption key */
+ control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS |
+ IEEE80211_TXCTL_USE_CTS_PROTECT);
+ control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT |
+ IEEE80211_TXCTL_NO_ACK;
+ control->antenna_sel_tx = 0; /* default to default antenna */
+
+ /* for every radiotap entry that is present (returns -ve on end or
+ * on error)
+ */
+
+ while (ieee80211_radiotap_iterator_next(&iterator) >= 0) {
+ int i, target_rate;
+
+ /* see if this argument is something we can use */
+
+ switch (iterator.this_arg_index) {
+
+ case IEEE80211_RADIOTAP_RATE:
+ /* radiotap "rate" u8 is in
+ * 500kbps units, eg, 0x02=1Mbps
+ * ieee80211 "rate" int is
+ * in 100kbps units, eg, 0x0a=1Mbps
+ */
+ target_rate = (*iterator.this_arg) * 5;
+ for (i = 0; i < hw_mode->num_rates; i++) {
+ struct ieee80211_rate *r = &hw_mode->rates[i];
+
+ if (r->rate > target_rate)
+ continue;
+
+ control->rate = r;
+
+ if (r->flags & IEEE80211_RATE_PREAMBLE2)
+ control->tx_rate = r->val2;
+ else
+ control->tx_rate = r->val;
+
+ /* end on exact match */
+ if (r->rate == target_rate)
+ i = hw_mode->num_rates;
+
+ }
+ break;
+
+ case IEEE80211_RADIOTAP_ANTENNA:
+ /* radiotap uses 0 for 1st ant,
+ * mac80211 is 1 for 1st ant
+ * absence of IEEE80211_RADIOTAP_ANTENNA
+ * gives default/diversity
+ */
+ control->antenna_sel_tx = (*iterator.this_arg) + 1;
+ break;
+
+ case IEEE80211_RADIOTAP_DBM_TX_POWER:
+ control->power_level = *iterator.this_arg;
+ break;
+
+ default:
+ break;
+ }
+
+ }
+
+ /* remove the radiotap header
+ * rthdr->it_len was sanity-checked against skb->len by iterator init
+ */
+ skb_pull(skb, le16_to_cpu(rthdr->it_len));
+
+ return TXRX_CONTINUE;
+}
+
+
+static ieee80211_txrx_result inline
__ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
struct sk_buff *skb,
struct net_device *dev,
@@ -1078,6 +1182,9 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct ieee80211_sub_if_data *sdata;
+ ieee80211_txrx_result res = TXRX_CONTINUE;
+
int hdrlen;
memset(tx, 0, sizeof(*tx));
@@ -1087,7 +1194,32 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
tx->sdata = IEEE80211_DEV_TO_SUB_IF(dev);
tx->sta = sta_info_get(local, hdr->addr1);
tx->fc = le16_to_cpu(hdr->frame_control);
+
+ /* set defaults for things that can be set by
+ * injected radiotap headers
+ */
+
control->power_level = local->hw.conf.power_level;
+ control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
+ if (local->sta_antenna_sel != STA_ANTENNA_SEL_AUTO && tx->sta)
+ control->antenna_sel_tx = tx->sta->antenna_sel_tx;
+
+ /* process and remove the injection radiotap header */
+
+ sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ if (unlikely(sdata->type == IEEE80211_IF_TYPE_MNTR)) {
+ if (__ieee80211_convert_radiotap_to_control_and_remove(
+ tx, skb, control) == TXRX_DROP) {
+ return TXRX_DROP;
+ }
+ /* we removed the radiotap header after this point,
+ * we filled control with what we could use
+ * set to the actual ieee header now
+ */
+ hdr = (struct ieee80211_hdr *) skb->data;
+ res = TXRX_QUEUED; /* indication it was monitor packet */
+ }
+
tx->u.tx.control = control;
tx->u.tx.unicast = !is_multicast_ether_addr(hdr->addr1);
if (is_multicast_ether_addr(hdr->addr1))
@@ -1104,9 +1236,6 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
tx->sta->clear_dst_mask = 0;
}
- control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
- if (local->sta_antenna_sel != STA_ANTENNA_SEL_AUTO && tx->sta)
- control->antenna_sel_tx = tx->sta->antenna_sel_tx;
hdrlen = ieee80211_get_hdrlen(tx->fc);
if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
@@ -1114,6 +1243,7 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
}
control->flags |= IEEE80211_TXCTL_FIRST_FRAGMENT;
+ return res;
}
static int inline is_ieee80211_device(struct net_device *dev,
@@ -1221,7 +1351,7 @@ static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
struct sta_info *sta;
ieee80211_tx_handler *handler;
struct ieee80211_txrx_data tx;
- ieee80211_txrx_result res = TXRX_DROP;
+ ieee80211_txrx_result res = TXRX_DROP, res_prepare;
int ret, i;
WARN_ON(__ieee80211_queue_pending(local, control->queue));
@@ -1231,15 +1361,26 @@ static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
return 0;
}
- __ieee80211_tx_prepare(&tx, skb, dev, control);
+ res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
+
+ if (res_prepare == TXRX_DROP) {
+ dev_kfree_skb(skb);
+ return 0;
+ }
+
sta = tx.sta;
tx.u.tx.mgmt_interface = mgmt;
tx.u.tx.mode = local->hw.conf.mode;
- for (handler = local->tx_handlers; *handler != NULL; handler++) {
- res = (*handler)(&tx);
- if (res != TXRX_CONTINUE)
- break;
+ if (res_prepare == TXRX_QUEUED) { /* if it was an injected packet */
+ res = TXRX_CONTINUE;
+ } else {
+ for (handler = local->tx_handlers; *handler != NULL;
+ handler++) {
+ res = (*handler)(&tx);
+ if (res != TXRX_CONTINUE)
+ break;
+ }
}
skb = tx.skb; /* handlers are allowed to change skb */
@@ -1473,6 +1614,51 @@ static int ieee80211_subif_start_xmit(struct sk_buff *skb,
goto fail;
}
+ if (unlikely(sdata->type == IEEE80211_IF_TYPE_MNTR)) {
+ struct ieee80211_radiotap_header * prthdr =
+ (struct ieee80211_radiotap_header *)skb->data;
+
+ /* there must be a radiotap header at the
+ * start in this case
+ */
+
+ if (unlikely(prthdr->it_version)) {
+ /* only version 0 is supported */
+ ret = 0;
+ goto fail;
+ }
+
+ skb->dev = local->mdev;
+
+ pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
+ memset(pkt_data, 0, sizeof(struct ieee80211_tx_packet_data));
+ pkt_data->ifindex = sdata->dev->ifindex;
+ pkt_data->mgmt_iface = 0;
+ pkt_data->do_not_encrypt = 1;
+
+ /* above needed because we set skb device to master */
+
+ /* fix up the pointers accounting for the radiotap
+ * header still being in there. We are being given
+ * a precooked IEEE80211 header so no need for
+ * normal processing
+ */
+
+ skb->mac.raw = skb->data+prthdr->it_len;
+ skb->nh.raw = skb->data+prthdr->it_len+
+ sizeof(struct ieee80211_hdr);
+ skb->h.raw = skb->data+prthdr->it_len+
+ sizeof(struct ieee80211_hdr);
+
+ /* pass the radiotap header up to
+ * the next stage intact
+ */
+
+ dev_queue_xmit(skb);
+
+ return 0;
+ }
+
nh_pos = skb->nh.raw - skb->data;
h_pos = skb->h.raw - skb->data;
--
^ permalink raw reply related [flat|nested] 6+ messages in thread