net/wireless/radiotap.c

58  * ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
59  * @iterator: radiotap_iterator to initialize
66  * This function initializes an opaque iterator struct which can then
72  * call __ieee80211_radiotap_iterator_init() to init a semi-opaque iterator
77  * The iterator's @this_arg member points to the start of the argument
79  * found in the iterator's @this_arg_index member.  This arg index corresponds
84  * iterator->max_length after executing ieee80211_radiotap_iterator_init()
88  * You must take care when dereferencing iterator.this_arg
90  * get_unaligned((type *)iterator.this_arg) to dereference
91  * iterator.this_arg for type "type" safely on all arches.
98 	struct ieee80211_radiotap_iterator *iterator,
114 	iterator->_rtheader = radiotap_header;
115 	iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
116 	iterator->_arg_index = 0;
117 	iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
118 	iterator->_arg = (uint8_t *)radiotap_header->it_optional;
119 	iterator->_reset_on_ext = 0;
120 	iterator->_next_bitmap = radiotap_header->it_optional;
121 	iterator->_vns = vns;
122 	iterator->current_namespace = &radiotap_ns;
123 	iterator->is_radiotap_ns = 1;
127 	if (iterator->_bitmap_shifter & (BIT(IEEE80211_RADIOTAP_EXT))) {
128 		if ((unsigned long)iterator->_arg -
129 		    (unsigned long)iterator->_rtheader + sizeof(uint32_t) >
130 		    (unsigned long)iterator->_max_length)
132 		while (get_unaligned_le32(iterator->_arg) &
134 			iterator->_arg += sizeof(uint32_t);
142 			if ((unsigned long)iterator->_arg -
143 			    (unsigned long)iterator->_rtheader +
145 			    (unsigned long)iterator->_max_length)
149 		iterator->_arg += sizeof(uint32_t);
158 	iterator->this_arg = iterator->_arg;
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];
190  * ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
191  * @iterator: radiotap_iterator to move to next arg (if any)
206  * You must take care when dereferencing iterator.this_arg
208  * get_unaligned((type *)iterator.this_arg) to dereference
209  * iterator.this_arg for type "type" safely on all arches.
213 	struct ieee80211_radiotap_iterator *iterator)
221 		if ((iterator->_arg_index % 32) == IEEE80211_RADIOTAP_EXT &&
222 		    !(iterator->_bitmap_shifter & 1))
225 		if (!(iterator->_bitmap_shifter & 1))
229 		switch (iterator->_arg_index % 32) {
240 			if (!iterator->current_namespace ||
241 			    iterator->_arg_index >= iterator->current_namespace->n_bits) {
242 				if (iterator->current_namespace == &radiotap_ns)
246 				align = iterator->current_namespace->align_size[iterator->_arg_index].align;
247 				size = iterator->current_namespace->align_size[iterator->_arg_index].size;
251 				iterator->_arg = iterator->_next_ns_data;
253 				iterator->current_namespace = NULL;
271 		pad = ((unsigned long)iterator->_arg -
272 		       (unsigned long)iterator->_rtheader) & (align - 1);
275 			iterator->_arg += align - pad;
277 		if (iterator->_arg_index % 32 == IEEE80211_RADIOTAP_VENDOR_NAMESPACE) {
280 			if ((unsigned long)iterator->_arg + size -
281 			    (unsigned long)iterator->_rtheader >
282 			    (unsigned long)iterator->_max_length)
285 			oui = (*iterator->_arg << 16) |
286 				(*(iterator->_arg + 1) << 8) |
287 				*(iterator->_arg + 2);
288 			subns = *(iterator->_arg + 3);
290 			find_ns(iterator, oui, subns);
292 			vnslen = get_unaligned_le16(iterator->_arg + 4);
293 			iterator->_next_ns_data = iterator->_arg + size + vnslen;
294 			if (!iterator->current_namespace)
302 		iterator->this_arg_index = iterator->_arg_index;
303 		iterator->this_arg = iterator->_arg;
304 		iterator->this_arg_size = size;
307 		iterator->_arg += size;
316 		if ((unsigned long)iterator->_arg -
317 		    (unsigned long)iterator->_rtheader >
318 		    (unsigned long)iterator->_max_length)
322 		switch (iterator->_arg_index % 32) {
324 			iterator->_reset_on_ext = 1;
326 			iterator->is_radiotap_ns = 0;
333 			iterator->this_arg_index =
335 			if (!iterator->current_namespace)
339 			iterator->_reset_on_ext = 1;
340 			iterator->current_namespace = &radiotap_ns;
341 			iterator->is_radiotap_ns = 1;
348 			iterator->_bitmap_shifter =
349 				get_unaligned_le32(iterator->_next_bitmap);
350 			iterator->_next_bitmap++;
351 			if (iterator->_reset_on_ext)
352 				iterator->_arg_index = 0;
354 				iterator->_arg_index++;
355 			iterator->_reset_on_ext = 0;
361 			iterator->_bitmap_shifter >>= 1;
362 			iterator->_arg_index++;