+++ /dev/null
-/*
- * 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 "radiotap_iter.h"
-#include "platform.h"
-#if defined(ANDROID) || defined(__ANDROID__)
- #include "../byteorder.h"
-#endif
-
-/* function prototypes and related defs are in radiotap_iter.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, },
- [IEEE80211_RADIOTAP_MCS] = { .align = 1, .size = 3, },
- [IEEE80211_RADIOTAP_AMPDU_STATUS] = { .align = 4, .size = 8, },
- /*
- * 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
- * @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: parse.c
- */
-
-int ieee80211_radiotap_iterator_init(
- struct ieee80211_radiotap_iterator *iterator,
- struct ieee80211_radiotap_header *radiotap_header,
- int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
-{
- /* must at least have the radiotap header */
- if (max_length < (int)sizeof(struct ieee80211_radiotap_header))
- return -EINVAL;
-
- /* 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 < 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 = (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;
-#ifdef RADIOTAP_SUPPORT_OVERRIDES
- iterator->n_overrides = 0;
- iterator->overrides = NULL;
-#endif
-
- /* find payload start allowing for extended bitmap(s) */
-
- if (iterator->_bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT)) {
- if ((unsigned long)iterator->_arg -
- (unsigned long)iterator->_rtheader + sizeof(uint32_t) >
- (unsigned long)iterator->_max_length)
- return -EINVAL;
- while (get_unaligned_le32(iterator->_arg) &
- (1 << IEEE80211_RADIOTAP_EXT)) {
- iterator->_arg += sizeof(uint32_t);
-
- /*
- * check for insanity where the present bitmaps
- * keep claiming to extend up to or even beyond the
- * stated radiotap header length
- */
-
- if ((unsigned long)iterator->_arg -
- (unsigned long)iterator->_rtheader +
- sizeof(uint32_t) >
- (unsigned long)iterator->_max_length)
- return -EINVAL;
- }
-
- iterator->_arg += sizeof(uint32_t);
-
- /*
- * no need to check again for blowing past stated radiotap
- * header length, because ieee80211_radiotap_iterator_next
- * checks it before it is dereferenced
- */
- }
-
- iterator->this_arg = iterator->_arg;
-
- /* we are all initialized happily */
-
- return 0;
-}
-
-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;
- }
-}
-
-#ifdef RADIOTAP_SUPPORT_OVERRIDES
-static int find_override(struct ieee80211_radiotap_iterator *iterator,
- int *align, int *size)
-{
- int i;
-
- if (!iterator->overrides)
- return 0;
-
- for (i = 0; i < iterator->n_overrides; i++) {
- if (iterator->_arg_index == iterator->overrides[i].field) {
- *align = iterator->overrides[i].align;
- *size = iterator->overrides[i].size;
- if (!*align) /* erroneous override */
- return 0;
- return 1;
- }
- }
-
- return 0;
-}
-#endif
-
-
-/**
- * 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)
-{
- while (1) {
- int hit = 0;
- int pad, align, size, subns;
- uint32_t oui;
-
- /* 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:
-#ifdef RADIOTAP_SUPPORT_OVERRIDES
- if (find_override(iterator, &align, &size)) {
- /* all set */
- } else
-#endif
- 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
- *
- * 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.
- */
-
- pad = ((unsigned long)iterator->_arg -
- (unsigned long)iterator->_rtheader) & (align - 1);
-
- if (pad)
- iterator->_arg += align - pad;
-
- if (iterator->_arg_index % 32 == IEEE80211_RADIOTAP_VENDOR_NAMESPACE) {
- int vnslen;
-
- if ((unsigned long)iterator->_arg + size -
- (unsigned long)iterator->_rtheader >
- (unsigned long)iterator->_max_length)
- return -EINVAL;
-
- oui = (*iterator->_arg << 16) |
- (*(iterator->_arg + 1) << 8) |
- *(iterator->_arg + 2);
- subns = *(iterator->_arg + 3);
-
- find_ns(iterator, oui, subns);
-
- vnslen = get_unaligned_le16(iterator->_arg + 4);
- iterator->_next_ns_data = iterator->_arg + size + vnslen;
- if (!iterator->current_namespace)
- size += vnslen;
- }
-
- /*
- * 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;
- iterator->this_arg_size = size;
-
- /* internally move on the size of this arg */
- iterator->_arg += size;
-
- /*
- * 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 ((unsigned long)iterator->_arg -
- (unsigned long)iterator->_rtheader >
- (unsigned long)iterator->_max_length)
- return -EINVAL;
-
- /* these special ones are valid in each bitmap word */
- switch (iterator->_arg_index % 32) {
- case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
- iterator->_reset_on_ext = 1;
-
- iterator->is_radiotap_ns = 0;
- /*
- * If parser didn't register this vendor
- * namespace with us, allow it to show it
- * as 'raw. Do do that, set argument index
- * to vendor namespace.
- */
- iterator->this_arg_index =
- IEEE80211_RADIOTAP_VENDOR_NAMESPACE;
- if (!iterator->current_namespace)
- hit = 1;
- goto next_entry;
- case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
- iterator->_reset_on_ext = 1;
- iterator->current_namespace = &radiotap_ns;
- iterator->is_radiotap_ns = 1;
- goto next_entry;
- 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;
- }
-}
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