lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

wireless: update radiotap parser

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

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 * 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 * struct ieee80211_radiotap_iterator - tracks walk thru present radiotap args
* @rtheader: pointer to the radiotap header we are walking through * @this_arg_index: index of current arg, valid after each successful call
* @max_length: length of radiotap header in cpu byte ordering * to ieee80211_radiotap_iterator_next()
* @this_arg_index: IEEE80211_RADIOTAP_... index of current arg * @this_arg: pointer to current radiotap arg; it is valid after each
* @this_arg: pointer to current radiotap arg * call to ieee80211_radiotap_iterator_next() but also after
* @arg_index: internal next argument index * ieee80211_radiotap_iterator_init() where it will point to
* @arg: internal next argument pointer * the beginning of the actual data portion
* @next_bitmap: internal pointer to next present u32 * @this_arg_size: length of the current arg, for convenience
* @bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present * @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_iterator {
struct ieee80211_radiotap_header *rtheader; struct ieee80211_radiotap_header *_rtheader;
int max_length; const struct ieee80211_radiotap_vendor_namespaces *_vns;
int this_arg_index; const struct ieee80211_radiotap_namespace *current_namespace;
u8 *this_arg;
int arg_index; unsigned char *_arg, *_next_ns_data;
u8 *arg; uint32_t *_next_bitmap;
__le32 *next_bitmap;
u32 bitmap_shifter; 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( extern int ieee80211_radiotap_iterator_init(
struct ieee80211_radiotap_iterator *iterator, struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header, struct ieee80211_radiotap_header *radiotap_header,
int max_length); int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns);
extern int ieee80211_radiotap_iterator_next( 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 rfc1042_header[6];
extern const unsigned char bridge_tunnel_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_TX_FLAGS = 15,
IEEE80211_RADIOTAP_RTS_RETRIES = 16, IEEE80211_RADIOTAP_RTS_RETRIES = 16,
IEEE80211_RADIOTAP_DATA_RETRIES = 17, 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 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_radiotap_header *) skb->data;
struct ieee80211_supported_band *sband; struct ieee80211_supported_band *sband;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 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]; 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 * because it will be recomputed and added
* on transmission * on transmission
*/ */
if (skb->len < (iterator.max_length + FCS_LEN)) if (skb->len < (iterator._max_length + FCS_LEN))
return false; return false;
skb_trim(skb, skb->len - FCS_LEN); 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 * remove the radiotap header
* iterator->max_length was sanity-checked against * iterator->_max_length was sanity-checked against
* skb->len by iterator init * skb->len by iterator init
*/ */
skb_pull(skb, iterator.max_length); skb_pull(skb, iterator._max_length);
return true; return true;
} }

305
net/wireless/radiotap.c
View File

@@ -2,6 +2,16 @@
* Radiotap parser * Radiotap parser
* *
* Copyright 2007 Andy Green <andy@warmcat.com> * 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> #include <net/cfg80211.h>
@@ -10,6 +20,35 @@
/* function prototypes and related defs are in include/net/cfg80211.h */ /* 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 * ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
* @iterator: radiotap_iterator to initialize * @iterator: radiotap_iterator to initialize
@@ -50,9 +89,9 @@
*/ */
int ieee80211_radiotap_iterator_init( int ieee80211_radiotap_iterator_init(
struct ieee80211_radiotap_iterator *iterator, struct ieee80211_radiotap_iterator *iterator,
struct ieee80211_radiotap_header *radiotap_header, struct ieee80211_radiotap_header *radiotap_header,
int max_length) int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
{ {
/* Linux only supports version 0 radiotap format */ /* Linux only supports version 0 radiotap format */
if (radiotap_header->it_version) if (radiotap_header->it_version)
@@ -62,19 +101,24 @@ int ieee80211_radiotap_iterator_init(
if (max_length < get_unaligned_le16(&radiotap_header->it_len)) if (max_length < get_unaligned_le16(&radiotap_header->it_len))
return -EINVAL; return -EINVAL;
iterator->rtheader = radiotap_header; iterator->_rtheader = radiotap_header;
iterator->max_length = get_unaligned_le16(&radiotap_header->it_len); iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
iterator->arg_index = 0; iterator->_arg_index = 0;
iterator->bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present); iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header); iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
iterator->this_arg = NULL; 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) */ /* find payload start allowing for extended bitmap(s) */
if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) { if (iterator->_bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT)) {
while (get_unaligned_le32(iterator->arg) & while (get_unaligned_le32(iterator->_arg) &
(1 << IEEE80211_RADIOTAP_EXT)) { (1 << IEEE80211_RADIOTAP_EXT)) {
iterator->arg += sizeof(u32); iterator->_arg += sizeof(uint32_t);
/* /*
* check for insanity where the present bitmaps * check for insanity where the present bitmaps
@@ -82,12 +126,13 @@ int ieee80211_radiotap_iterator_init(
* stated radiotap header length * stated radiotap header length
*/ */
if (((ulong)iterator->arg - if ((unsigned long)iterator->_arg -
(ulong)iterator->rtheader) > iterator->max_length) (unsigned long)iterator->_rtheader >
(unsigned long)iterator->_max_length)
return -EINVAL; return -EINVAL;
} }
iterator->arg += sizeof(u32); iterator->_arg += sizeof(uint32_t);
/* /*
* no need to check again for blowing past stated radiotap * 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 */ /* we are all initialized happily */
return 0; return 0;
} }
EXPORT_SYMBOL(ieee80211_radiotap_iterator_init); 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 * 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( int ieee80211_radiotap_iterator_next(
struct ieee80211_radiotap_iterator *iterator) struct ieee80211_radiotap_iterator *iterator)
{ {
while (1) {
/*
* 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)) {
int hit = 0; 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 */ 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 * 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 * Note that these alignments are relative to the start
* elements inside arg, so we use upper nybble of length * of the radiotap header. There is no guarantee
* 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 * that the radiotap header itself is aligned on any
* kind of boundary. * kind of boundary.
* *
* the above is why get_unaligned() is used to dereference * The above is why get_unaligned() is used to dereference
* multibyte elements from the radiotap area * multibyte elements from the radiotap area.
*/ */
pad = (((ulong)iterator->arg) - pad = ((unsigned long)iterator->_arg -
((ulong)iterator->rtheader)) & (unsigned long)iterator->_rtheader) & (align - 1);
((rt_sizes[iterator->arg_index] >> 4) - 1);
if (pad) if (pad)
iterator->arg += iterator->_arg += align - pad;
(rt_sizes[iterator->arg_index] >> 4) - pad;
/* /*
* this is what we will return to user, but we need to * this is what we will return to user, but we need to
* move on first so next call has something fresh to test * move on first so next call has something fresh to test
*/ */
iterator->this_arg_index = iterator->arg_index; iterator->this_arg_index = iterator->_arg_index;
iterator->this_arg = iterator->arg; iterator->this_arg = iterator->_arg;
hit = 1; iterator->this_arg_size = size;
/* internally move on the size of this arg */ /* 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 * 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. * max_length on the last arg, never exceeding it.
*/ */
if (((ulong)iterator->arg - (ulong)iterator->rtheader) > if ((unsigned long)iterator->_arg -
iterator->max_length) (unsigned long)iterator->_rtheader >
(unsigned long)iterator->_max_length)
return -EINVAL; return -EINVAL;
next_entry: /* these special ones are valid in each bitmap word */
iterator->arg_index++; switch (iterator->_arg_index % 32) {
if (unlikely((iterator->arg_index & 31) == 0)) { case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
/* completed current u32 bitmap */ iterator->_bitmap_shifter >>= 1;
if (iterator->bitmap_shifter & 1) { iterator->_arg_index++;
/* b31 was set, there is more */
/* move to next u32 bitmap */ iterator->_reset_on_ext = 1;
iterator->bitmap_shifter =
get_unaligned_le32(iterator->next_bitmap); vnslen = get_unaligned_le16(iterator->this_arg + 4);
iterator->next_bitmap++; iterator->_next_ns_data = iterator->_arg + vnslen;
} else oui = (*iterator->this_arg << 16) |
/* no more bitmaps: end */ (*(iterator->this_arg + 1) << 8) |
iterator->arg_index = sizeof(rt_sizes); *(iterator->this_arg + 2);
} else /* just try the next bit */ subns = *(iterator->this_arg + 3);
iterator->bitmap_shifter >>= 1;
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 we found a valid arg earlier, return it now */
if (hit) if (hit)
return 0; return 0;
} }
/* we don't know how to handle any more args, we're done */
return -ENOENT;
} }
EXPORT_SYMBOL(ieee80211_radiotap_iterator_next); EXPORT_SYMBOL(ieee80211_radiotap_iterator_next);