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wireless: update radiotap parser 

Upstream radiotap has adopted the namespace
proposal David Young made and I then took care
of, for which I had adapted the radiotap parser
as a library outside the kernel. This brings
the in-kernel parser up to speed.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2010-02-03 10:24:30 +01:00 committed by John W. Linville
parent 690680360c
commit 33e5a2f776
4 changed files with 272 additions and 131 deletions
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85
include/net/cfg80211.h
View File

@ -1561,37 +1561,82 @@ ieee80211_get_response_rate(struct ieee80211_supported_band *sband,
* Documentation in Documentation/networking/radiotap-headers.txt
*/
struct radiotap_align_size {
uint8_t align:4, size:4;
};
struct ieee80211_radiotap_namespace {
const struct radiotap_align_size *align_size;
int n_bits;
uint32_t oui;
uint8_t subns;
};
struct ieee80211_radiotap_vendor_namespaces {
const struct ieee80211_radiotap_namespace *ns;
int n_ns;
};
/**
* struct ieee80211_radiotap_iterator - tracks walk thru present radiotap args
* @rtheader: pointer to the radiotap header we are walking through
* @max_length: length of radiotap header in cpu byte ordering
* @this_arg_index: IEEE80211_RADIOTAP_... index of current arg
* @this_arg: pointer to current radiotap arg
* @arg_index: internal next argument index
* @arg: internal next argument pointer
* @next_bitmap: internal pointer to next present u32
* @bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present
* @this_arg_index: index of current arg, valid after each successful call
* to ieee80211_radiotap_iterator_next()
* @this_arg: pointer to current radiotap arg; it is valid after each
* call to ieee80211_radiotap_iterator_next() but also after
* ieee80211_radiotap_iterator_init() where it will point to
* the beginning of the actual data portion
* @this_arg_size: length of the current arg, for convenience
* @current_namespace: pointer to the current namespace definition
* (or internally %NULL if the current namespace is unknown)
* @is_radiotap_ns: indicates whether the current namespace is the default
* radiotap namespace or not
*
* @overrides: override standard radiotap fields
* @n_overrides: number of overrides
*
* @_rtheader: pointer to the radiotap header we are walking through
* @_max_length: length of radiotap header in cpu byte ordering
* @_arg_index: next argument index
* @_arg: next argument pointer
* @_next_bitmap: internal pointer to next present u32
* @_bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present
* @_vns: vendor namespace definitions
* @_next_ns_data: beginning of the next namespace's data
* @_reset_on_ext: internal; reset the arg index to 0 when going to the
* next bitmap word
*
* Describes the radiotap parser state. Fields prefixed with an underscore
* must not be used by users of the parser, only by the parser internally.
*/
struct ieee80211_radiotap_iterator {
struct ieee80211_radiotap_header *rtheader;
int max_length;
int this_arg_index;
u8 *this_arg;
struct ieee80211_radiotap_header *_rtheader;
const struct ieee80211_radiotap_vendor_namespaces *_vns;
const struct ieee80211_radiotap_namespace *current_namespace;
int arg_index;
u8 *arg;
__le32 *next_bitmap;
u32 bitmap_shifter;
unsigned char *_arg, *_next_ns_data;
uint32_t *_next_bitmap;
unsigned char *this_arg;
int this_arg_index;
int this_arg_size;
int is_radiotap_ns;
int _max_length;
int _arg_index;
uint32_t _bitmap_shifter;
int _reset_on_ext;
};
extern int ieee80211_radiotap_iterator_init(
struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header,
int max_length);
struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header,
int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns);
extern int ieee80211_radiotap_iterator_next(
struct ieee80211_radiotap_iterator *iterator);
struct ieee80211_radiotap_iterator *iterator);
extern const unsigned char rfc1042_header[6];
extern const unsigned char bridge_tunnel_header[6];

4
include/net/ieee80211_radiotap.h
View File

@ -198,6 +198,10 @@ enum ieee80211_radiotap_type {
IEEE80211_RADIOTAP_TX_FLAGS = 15,
IEEE80211_RADIOTAP_RTS_RETRIES = 16,
IEEE80211_RADIOTAP_DATA_RETRIES = 17,
/* valid in every it_present bitmap, even vendor namespaces */
IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
IEEE80211_RADIOTAP_VENDOR_NAMESPACE = 30,
IEEE80211_RADIOTAP_EXT = 31
};

9
net/mac80211/tx.c
View File

@ -1010,7 +1010,8 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
(struct ieee80211_radiotap_header *) skb->data;
struct ieee80211_supported_band *sband;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
NULL);
sband = tx->local->hw.wiphy->bands[tx->channel->band];
@ -1046,7 +1047,7 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
* because it will be recomputed and added
* on transmission
*/
if (skb->len < (iterator.max_length + FCS_LEN))
if (skb->len < (iterator._max_length + FCS_LEN))
return false;
skb_trim(skb, skb->len - FCS_LEN);
@ -1073,10 +1074,10 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
/*
* remove the radiotap header
* iterator->max_length was sanity-checked against
* iterator->_max_length was sanity-checked against
* skb->len by iterator init
*/
skb_pull(skb, iterator.max_length);
skb_pull(skb, iterator._max_length);
return true;
}

305
net/wireless/radiotap.c
View File

@ -2,6 +2,16 @@
* Radiotap parser
*
* Copyright 2007 Andy Green <andy@warmcat.com>
* Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See COPYING for more details.
*/
#include <net/cfg80211.h>
@ -10,6 +20,35 @@
/* function prototypes and related defs are in include/net/cfg80211.h */
static const struct radiotap_align_size rtap_namespace_sizes[] = {
[IEEE80211_RADIOTAP_TSFT] = { .align = 8, .size = 8, },
[IEEE80211_RADIOTAP_FLAGS] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_RATE] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_CHANNEL] = { .align = 2, .size = 4, },
[IEEE80211_RADIOTAP_FHSS] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_DBM_ANTNOISE] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_LOCK_QUALITY] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_TX_ATTENUATION] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_DBM_TX_POWER] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_ANTENNA] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_DB_ANTSIGNAL] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_DB_ANTNOISE] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_RX_FLAGS] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_TX_FLAGS] = { .align = 2, .size = 2, },
[IEEE80211_RADIOTAP_RTS_RETRIES] = { .align = 1, .size = 1, },
[IEEE80211_RADIOTAP_DATA_RETRIES] = { .align = 1, .size = 1, },
/*
* add more here as they are defined in radiotap.h
*/
};
static const struct ieee80211_radiotap_namespace radiotap_ns = {
.n_bits = sizeof(rtap_namespace_sizes) / sizeof(rtap_namespace_sizes[0]),
.align_size = rtap_namespace_sizes,
};
/**
* ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
* @iterator: radiotap_iterator to initialize
@ -50,9 +89,9 @@
*/
int ieee80211_radiotap_iterator_init(
struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header,
int max_length)
struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header,
int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
{
/* Linux only supports version 0 radiotap format */
if (radiotap_header->it_version)
@ -62,19 +101,24 @@ int ieee80211_radiotap_iterator_init(
if (max_length < get_unaligned_le16(&radiotap_header->it_len))
return -EINVAL;
iterator->rtheader = radiotap_header;
iterator->max_length = get_unaligned_le16(&radiotap_header->it_len);
iterator->arg_index = 0;
iterator->bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header);
iterator->this_arg = NULL;
iterator->_rtheader = radiotap_header;
iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
iterator->_arg_index = 0;
iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
iterator->_reset_on_ext = 0;
iterator->_next_bitmap = &radiotap_header->it_present;
iterator->_next_bitmap++;
iterator->_vns = vns;
iterator->current_namespace = &radiotap_ns;
iterator->is_radiotap_ns = 1;
/* find payload start allowing for extended bitmap(s) */
if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) {
while (get_unaligned_le32(iterator->arg) &
(1 << IEEE80211_RADIOTAP_EXT)) {
iterator->arg += sizeof(u32);
if (iterator->_bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT)) {
while (get_unaligned_le32(iterator->_arg) &
(1 << IEEE80211_RADIOTAP_EXT)) {
iterator->_arg += sizeof(uint32_t);
/*
* check for insanity where the present bitmaps
@ -82,12 +126,13 @@ int ieee80211_radiotap_iterator_init(
* stated radiotap header length
*/
if (((ulong)iterator->arg -
(ulong)iterator->rtheader) > iterator->max_length)
if ((unsigned long)iterator->_arg -
(unsigned long)iterator->_rtheader >
(unsigned long)iterator->_max_length)
return -EINVAL;
}
iterator->arg += sizeof(u32);
iterator->_arg += sizeof(uint32_t);
/*
* no need to check again for blowing past stated radiotap
@ -96,12 +141,36 @@ int ieee80211_radiotap_iterator_init(
*/
}
iterator->this_arg = iterator->_arg;
/* we are all initialized happily */
return 0;
}
EXPORT_SYMBOL(ieee80211_radiotap_iterator_init);
static void find_ns(struct ieee80211_radiotap_iterator *iterator,
uint32_t oui, uint8_t subns)
{
int i;
iterator->current_namespace = NULL;
if (!iterator->_vns)
return;
for (i = 0; i < iterator->_vns->n_ns; i++) {
if (iterator->_vns->ns[i].oui != oui)
continue;
if (iterator->_vns->ns[i].subns != subns)
continue;
iterator->current_namespace = &iterator->_vns->ns[i];
break;
}
}
/**
* ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
@ -127,99 +196,80 @@ EXPORT_SYMBOL(ieee80211_radiotap_iterator_init);
*/
int ieee80211_radiotap_iterator_next(
struct ieee80211_radiotap_iterator *iterator)
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,
[IEEE80211_RADIOTAP_RX_FLAGS] = 0x22,
[IEEE80211_RADIOTAP_TX_FLAGS] = 0x22,
[IEEE80211_RADIOTAP_RTS_RETRIES] = 0x11,
[IEEE80211_RADIOTAP_DATA_RETRIES] = 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)) {
while (1) {
int hit = 0;
int pad;
int pad, align, size, subns, vnslen;
uint32_t oui;
if (!(iterator->bitmap_shifter & 1))
/* if no more EXT bits, that's it */
if ((iterator->_arg_index % 32) == IEEE80211_RADIOTAP_EXT &&
!(iterator->_bitmap_shifter & 1))
return -ENOENT;
if (!(iterator->_bitmap_shifter & 1))
goto next_entry; /* arg not present */
/* get alignment/size of data */
switch (iterator->_arg_index % 32) {
case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
case IEEE80211_RADIOTAP_EXT:
align = 1;
size = 0;
break;
case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
align = 2;
size = 6;
break;
default:
if (!iterator->current_namespace ||
iterator->_arg_index >= iterator->current_namespace->n_bits) {
if (iterator->current_namespace == &radiotap_ns)
return -ENOENT;
align = 0;
} else {
align = iterator->current_namespace->align_size[iterator->_arg_index].align;
size = iterator->current_namespace->align_size[iterator->_arg_index].size;
}
if (!align) {
/* skip all subsequent data */
iterator->_arg = iterator->_next_ns_data;
/* give up on this namespace */
iterator->current_namespace = NULL;
goto next_entry;
}
break;
}
/*
* 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
* Note that 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.
*
* the above is why get_unaligned() is used to dereference
* multibyte elements from the radiotap area
* The above is why get_unaligned() is used to dereference
* multibyte elements from the radiotap area.
*/
pad = (((ulong)iterator->arg) -
((ulong)iterator->rtheader)) &
((rt_sizes[iterator->arg_index] >> 4) - 1);
pad = ((unsigned long)iterator->_arg -
(unsigned long)iterator->_rtheader) & (align - 1);
if (pad)
iterator->arg +=
(rt_sizes[iterator->arg_index] >> 4) - pad;
iterator->_arg += align - pad;
/*
* 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;
iterator->this_arg_index = iterator->_arg_index;
iterator->this_arg = iterator->_arg;
iterator->this_arg_size = size;
/* internally move on the size of this arg */
iterator->arg += rt_sizes[iterator->arg_index] & 0x0f;
iterator->_arg += size;
/*
* check for insanity where we are given a bitmap that
@ -228,32 +278,73 @@ int ieee80211_radiotap_iterator_next(
* max_length on the last arg, never exceeding it.
*/
if (((ulong)iterator->arg - (ulong)iterator->rtheader) >
iterator->max_length)
if ((unsigned long)iterator->_arg -
(unsigned long)iterator->_rtheader >
(unsigned long)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 =
get_unaligned_le32(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;
/* these special ones are valid in each bitmap word */
switch (iterator->_arg_index % 32) {
case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
iterator->_bitmap_shifter >>= 1;
iterator->_arg_index++;
iterator->_reset_on_ext = 1;
vnslen = get_unaligned_le16(iterator->this_arg + 4);
iterator->_next_ns_data = iterator->_arg + vnslen;
oui = (*iterator->this_arg << 16) |
(*(iterator->this_arg + 1) << 8) |
*(iterator->this_arg + 2);
subns = *(iterator->this_arg + 3);
find_ns(iterator, oui, subns);
iterator->is_radiotap_ns = 0;
/* allow parsers to show this information */
iterator->this_arg_index =
IEEE80211_RADIOTAP_VENDOR_NAMESPACE;
iterator->this_arg_size += vnslen;
if ((unsigned long)iterator->this_arg +
iterator->this_arg_size -
(unsigned long)iterator->_rtheader >
(unsigned long)(unsigned long)iterator->_max_length)
return -EINVAL;
hit = 1;
break;
case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
iterator->_bitmap_shifter >>= 1;
iterator->_arg_index++;
iterator->_reset_on_ext = 1;
iterator->current_namespace = &radiotap_ns;
iterator->is_radiotap_ns = 1;
break;
case IEEE80211_RADIOTAP_EXT:
/*
* bit 31 was set, there is more
* -- move to next u32 bitmap
*/
iterator->_bitmap_shifter =
get_unaligned_le32(iterator->_next_bitmap);
iterator->_next_bitmap++;
if (iterator->_reset_on_ext)
iterator->_arg_index = 0;
else
iterator->_arg_index++;
iterator->_reset_on_ext = 0;
break;
default:
/* we've got a hit! */
hit = 1;
next_entry:
iterator->_bitmap_shifter >>= 1;
iterator->_arg_index++;
}
/* if we found a valid arg earlier, return it now */
if (hit)
return 0;
}
/* we don't know how to handle any more args, we're done */
return -ENOENT;
}
EXPORT_SYMBOL(ieee80211_radiotap_iterator_next);