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Diffstat (limited to 'package/hostapd/files/radiotap.c')
| -rw-r--r-- | package/hostapd/files/radiotap.c | 287 |
1 files changed, 0 insertions, 287 deletions
diff --git a/package/hostapd/files/radiotap.c b/package/hostapd/files/radiotap.c deleted file mode 100644 index 804473f..0000000 --- a/package/hostapd/files/radiotap.c +++ /dev/null @@ -1,287 +0,0 @@ -/* - * Radiotap parser - * - * Copyright 2007 Andy Green <andy@warmcat.com> - * - * 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 README and COPYING for more details. - * - * - * Modified for userspace by Johannes Berg <johannes@sipsolutions.net> - * I only modified some things on top to ease syncing should bugs be found. - */ - -#include "includes.h" - -#include "common.h" -#include "radiotap_iter.h" - -#define le16_to_cpu le_to_host16 -#define le32_to_cpu le_to_host32 -#define __le32 uint32_t -#define ulong unsigned long -#define unlikely(cond) (cond) -#define get_unaligned(p) \ -({ \ - struct packed_dummy_struct { \ - typeof(*(p)) __val; \ - } __attribute__((packed)) *__ptr = (void *) (p); \ - \ - __ptr->__val; \ -}) - -/* function prototypes and related defs are in radiotap_iter.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 or a negative error code if there is a problem. - * - * 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. - * - * How to use: - * call __ieee80211_radiotap_iterator_init() to init a semi-opaque iterator - * struct ieee80211_radiotap_iterator (no need to init the struct beforehand) - * checking for a good 0 return code. Then loop calling - * __ieee80211_radiotap_iterator_next()... it returns either 0, - * -ENOENT if there are no more args to parse, or -EINVAL if there is a problem. - * The iterator's @this_arg member points to the start of the argument - * associated with the current argument index that is present, which can be - * found in the iterator's @this_arg_index member. This arg index corresponds - * to the IEEE80211_RADIOTAP_... defines. - * - * Radiotap header length: - * You can find the CPU-endian total radiotap header length in - * iterator->max_length after executing ieee80211_radiotap_iterator_init() - * successfully. - * - * Alignment Gotcha: - * You must take care when dereferencing iterator.this_arg - * for multibyte types... the pointer is not aligned. Use - * get_unaligned((type *)iterator.this_arg) to dereference - * iterator.this_arg for type "type" safely on all arches. - * - * Example code: - * See Documentation/networking/radiotap-headers.txt - */ - -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(get_unaligned(&radiotap_header->it_len))) - return -EINVAL; - - iterator->rtheader = radiotap_header; - iterator->max_length = le16_to_cpu(get_unaligned( - &radiotap_header->it_len)); - iterator->arg_index = 0; - iterator->bitmap_shifter = le32_to_cpu(get_unaligned( - &radiotap_header->it_present)); - iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header); - iterator->this_arg = NULL; - - /* find payload start allowing for extended bitmap(s) */ - - if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) { - while (le32_to_cpu(get_unaligned((__le32 *)iterator->arg)) & - (1<<IEEE80211_RADIOTAP_EXT)) { - iterator->arg += sizeof(u32); - - /* - * check for insanity where the present bitmaps - * keep claiming to extend up to or even beyond the - * stated radiotap header length - */ - - if (((ulong)iterator->arg - (ulong)iterator->rtheader) - > (ulong)iterator->max_length) - return -EINVAL; - } - - iterator->arg += sizeof(u32); - - /* - * no need to check again for blowing past stated radiotap - * header length, because ieee80211_radiotap_iterator_next - * checks it before it is dereferenced - */ - } - - /* we are all initialized happily */ - - return 0; -} - - -/** - * ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg - * @iterator: radiotap_iterator to move to next arg (if any) - * - * Returns: 0 if there is an argument to handle, - * -ENOENT if there are no more args or -EINVAL - * if there is something else wrong. - * - * This function provides the next radiotap arg index (IEEE80211_RADIOTAP_*) - * in @this_arg_index and sets @this_arg to point to the - * payload for the field. It takes care of alignment handling and extended - * present fields. @this_arg can be changed by the caller (eg, - * incremented to move inside a compound argument like - * IEEE80211_RADIOTAP_CHANNEL). The args pointed to are in - * little-endian format whatever the endianess of your CPU. - * - * Alignment Gotcha: - * You must take care when dereferencing iterator.this_arg - * for multibyte types... the pointer is not aligned. Use - * get_unaligned((type *)iterator.this_arg) to dereference - * iterator.this_arg for type "type" safely on all arches. - */ - -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, - [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 < (int) sizeof(rt_sizes)) { - int hit = 0; - int pad; - - 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. - * - * 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); - - if (pad) - iterator->arg += - (rt_sizes[iterator->arg_index] >> 4) - 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; - - /* 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 (((ulong)iterator->arg - (ulong)iterator->rtheader) > - (ulong) 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( - get_unaligned(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 0; - } - - /* we don't know how to handle any more args, we're done */ - return -ENOENT; -} |