src/utils/radiotap.c

53  * ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
54  * @iterator: radiotap_iterator to initialize
60  * This function initializes an opaque iterator struct which can then
66  * call __ieee80211_radiotap_iterator_init() to init a semi-opaque iterator
71  * The iterator's @this_arg member points to the start of the argument
73  * found in the iterator's @this_arg_index member.  This arg index corresponds
78  * iterator->max_length after executing ieee80211_radiotap_iterator_init()
82  * You must take care when dereferencing iterator.this_arg
84  * get_unaligned((type *)iterator.this_arg) to dereference
85  * iterator.this_arg for type "type" safely on all arches.
91 	struct ieee80211_radiotap_iterator *iterator,
107 	iterator->_rtheader = radiotap_header;
108 	iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
109 	iterator->_arg_index = 0;
110 	iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
111 	iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
112 	iterator->_next_ns_data = NULL;
113 	iterator->_reset_on_ext = 0;
114 	iterator->_next_bitmap = (le32 *) (((u8 *) radiotap_header) + offsetof(struct ieee80211_radiotap_header, it_present));
115 	iterator->_next_bitmap++;
116 	iterator->_vns = vns;
117 	iterator->current_namespace = &radiotap_ns;
118 	iterator->is_radiotap_ns = 1;
120 	iterator->n_overrides = 0;
121 	iterator->overrides = NULL;
126 	if (iterator->_bitmap_shifter & BIT(IEEE80211_RADIOTAP_EXT)) {
127 		if ((unsigned long)iterator->_arg -
128 		    (unsigned long)iterator->_rtheader + sizeof(uint32_t) >
129 		    (unsigned long)iterator->_max_length)
131 		while (get_unaligned_le32(iterator->_arg) &
133 			iterator->_arg += sizeof(uint32_t);
141 			if ((unsigned long)iterator->_arg -
142 			    (unsigned long)iterator->_rtheader +
144 			    (unsigned long)iterator->_max_length)
148 		iterator->_arg += sizeof(uint32_t);
157 	iterator->this_arg = iterator->_arg;
158 	iterator->this_arg_index = 0;
159 	iterator->this_arg_size = 0;
166 static void find_ns(struct ieee80211_radiotap_iterator *iterator,
171 	iterator->current_namespace = NULL;
173 	if (!iterator->_vns)
176 	for (i = 0; i < iterator->_vns->n_ns; i++) {
177 		if (iterator->_vns->ns[i].oui != oui)
179 		if (iterator->_vns->ns[i].subns != subns)
182 		iterator->current_namespace = &iterator->_vns->ns[i];
188 static int find_override(struct ieee80211_radiotap_iterator *iterator,
193 	if (!iterator->overrides)
196 	for (i = 0; i < iterator->n_overrides; i++) {
197 		if (iterator->_arg_index == iterator->overrides[i].field) {
198 			*align = iterator->overrides[i].align;
199 			*size = iterator->overrides[i].size;
212  * ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
213  * @iterator: radiotap_iterator to move to next arg (if any)
228  * You must take care when dereferencing iterator.this_arg
230  * get_unaligned((type *)iterator.this_arg) to dereference
231  * iterator.this_arg for type "type" safely on all arches.
235 	struct ieee80211_radiotap_iterator *iterator)
243 		if ((iterator->_arg_index % 32) == IEEE80211_RADIOTAP_EXT &&
244 		    !(iterator->_bitmap_shifter & 1))
247 		if (!(iterator->_bitmap_shifter & 1))
251 		switch (iterator->_arg_index % 32) {
263 			if (find_override(iterator, &align, &size)) {
267 			if (!iterator->current_namespace ||
268 			    iterator->_arg_index >= iterator->current_namespace->n_bits) {
269 				if (iterator->current_namespace == &radiotap_ns)
273 				align = iterator->current_namespace->align_size[iterator->_arg_index].align;
274 				size = iterator->current_namespace->align_size[iterator->_arg_index].size;
278 				iterator->_arg = iterator->_next_ns_data;
280 				iterator->current_namespace = NULL;
298 		pad = ((unsigned long)iterator->_arg -
299 		       (unsigned long)iterator->_rtheader) & (align - 1);
302 			iterator->_arg += align - pad;
304 		if (iterator->_arg_index % 32 == IEEE80211_RADIOTAP_VENDOR_NAMESPACE) {
307 			if ((unsigned long)iterator->_arg + size -
308 			    (unsigned long)iterator->_rtheader >
309 			    (unsigned long)iterator->_max_length)
312 			oui = (*iterator->_arg << 16) |
313 				(*(iterator->_arg + 1) << 8) |
314 				*(iterator->_arg + 2);
315 			subns = *(iterator->_arg + 3);
317 			find_ns(iterator, oui, subns);
319 			vnslen = get_unaligned_le16(iterator->_arg + 4);
320 			iterator->_next_ns_data = iterator->_arg + size + vnslen;
321 			if (!iterator->current_namespace)
329 		iterator->this_arg_index = iterator->_arg_index;
330 		iterator->this_arg = iterator->_arg;
331 		iterator->this_arg_size = size;
334 		iterator->_arg += size;
343 		if ((unsigned long)iterator->_arg -
344 		    (unsigned long)iterator->_rtheader >
345 		    (unsigned long)iterator->_max_length)
349 		switch (iterator->_arg_index % 32) {
351 			iterator->_reset_on_ext = 1;
353 			iterator->is_radiotap_ns = 0;
360 			iterator->this_arg_index =
362 			if (!iterator->current_namespace)
366 			iterator->_reset_on_ext = 1;
367 			iterator->current_namespace = &radiotap_ns;
368 			iterator->is_radiotap_ns = 1;
375 			iterator->_bitmap_shifter =
376 				get_unaligned_le32(iterator->_next_bitmap);
377 			iterator->_next_bitmap++;
378 			if (iterator->_reset_on_ext)
379 				iterator->_arg_index = 0;
381 				iterator->_arg_index++;
382 			iterator->_reset_on_ext = 0;
388 			iterator->_bitmap_shifter >>= 1;
389 			iterator->_arg_index++;