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45#include <linux/types.h>
46#include <linux/bitmap.h>
47#include <net/sctp/sctp.h>
48#include <net/sctp/sm.h>
49
50static void sctp_tsnmap_update(struct sctp_tsnmap *map);
51static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
52 __u16 len, __u16 *start, __u16 *end);
53static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap);
54
55
56struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *map, __u16 len,
57 __u32 initial_tsn, gfp_t gfp)
58{
59 if (!map->tsn_map) {
60 map->tsn_map = kzalloc(len>>3, gfp);
61 if (map->tsn_map == NULL)
62 return NULL;
63
64 map->len = len;
65 } else {
66 bitmap_zero(map->tsn_map, map->len);
67 }
68
69
70 map->base_tsn = initial_tsn;
71 map->cumulative_tsn_ack_point = initial_tsn - 1;
72 map->max_tsn_seen = map->cumulative_tsn_ack_point;
73 map->num_dup_tsns = 0;
74
75 return map;
76}
77
78void sctp_tsnmap_free(struct sctp_tsnmap *map)
79{
80 map->len = 0;
81 kfree(map->tsn_map);
82}
83
84
85
86
87
88
89
90int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn)
91{
92 u32 gap;
93
94
95 if (TSN_lte(tsn, map->cumulative_tsn_ack_point))
96 return 1;
97
98
99
100
101 if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
102 return -1;
103
104
105 gap = tsn - map->base_tsn;
106
107
108 if (gap < map->len && test_bit(gap, map->tsn_map))
109 return 1;
110 else
111 return 0;
112}
113
114
115
116int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn)
117{
118 u16 gap;
119
120 if (TSN_lt(tsn, map->base_tsn))
121 return 0;
122
123 gap = tsn - map->base_tsn;
124
125 if (gap >= map->len && !sctp_tsnmap_grow(map, gap))
126 return -ENOMEM;
127
128 if (!sctp_tsnmap_has_gap(map) && gap == 0) {
129
130
131
132
133 map->max_tsn_seen++;
134 map->cumulative_tsn_ack_point++;
135 map->base_tsn++;
136 } else {
137
138
139
140
141
142 if (TSN_lt(map->max_tsn_seen, tsn))
143 map->max_tsn_seen = tsn;
144
145
146 set_bit(gap, map->tsn_map);
147
148
149
150
151 sctp_tsnmap_update(map);
152 }
153
154 return 0;
155}
156
157
158
159SCTP_STATIC void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map,
160 struct sctp_tsnmap_iter *iter)
161{
162
163 iter->start = map->cumulative_tsn_ack_point + 1;
164}
165
166
167
168
169SCTP_STATIC int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map,
170 struct sctp_tsnmap_iter *iter,
171 __u16 *start, __u16 *end)
172{
173 int ended = 0;
174 __u16 start_ = 0, end_ = 0, offset;
175
176
177 if (TSN_lte(map->max_tsn_seen, iter->start))
178 return 0;
179
180 offset = iter->start - map->base_tsn;
181 sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len,
182 &start_, &end_);
183
184
185 if (start_ && !end_)
186 end_ = map->len - 1;
187
188
189
190
191 if (end_) {
192
193
194
195 *start = start_ + 1;
196 *end = end_ + 1;
197
198
199 iter->start = map->cumulative_tsn_ack_point + *end + 1;
200 ended = 1;
201 }
202
203 return ended;
204}
205
206
207void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn)
208{
209 u32 gap;
210
211 if (TSN_lt(tsn, map->base_tsn))
212 return;
213 if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
214 return;
215
216
217 if (TSN_lt(map->max_tsn_seen, tsn))
218 map->max_tsn_seen = tsn;
219
220 gap = tsn - map->base_tsn + 1;
221
222 map->base_tsn += gap;
223 map->cumulative_tsn_ack_point += gap;
224 if (gap >= map->len) {
225
226
227
228 bitmap_zero(map->tsn_map, map->len);
229 } else {
230
231
232
233 bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len);
234 sctp_tsnmap_update(map);
235 }
236}
237
238
239
240
241
242
243
244
245static void sctp_tsnmap_update(struct sctp_tsnmap *map)
246{
247 u16 len;
248 unsigned long zero_bit;
249
250
251 len = map->max_tsn_seen - map->cumulative_tsn_ack_point;
252 zero_bit = find_first_zero_bit(map->tsn_map, len);
253 if (!zero_bit)
254 return;
255
256 map->base_tsn += zero_bit;
257 map->cumulative_tsn_ack_point += zero_bit;
258
259 bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len);
260}
261
262
263
264__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
265{
266 __u32 cum_tsn = map->cumulative_tsn_ack_point;
267 __u32 max_tsn = map->max_tsn_seen;
268 __u32 base_tsn = map->base_tsn;
269 __u16 pending_data;
270 u32 gap, i;
271
272 pending_data = max_tsn - cum_tsn;
273 gap = max_tsn - base_tsn;
274
275 if (gap == 0 || gap >= map->len)
276 goto out;
277
278 for (i = 0; i < gap+1; i++) {
279 if (test_bit(i, map->tsn_map))
280 pending_data--;
281 }
282
283out:
284 return pending_data;
285}
286
287
288
289
290
291
292
293static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
294 __u16 len, __u16 *start, __u16 *end)
295{
296 int i = off;
297
298
299
300
301
302
303
304
305 i = find_next_bit(map, len, off);
306 if (i < len)
307 *start = i;
308
309
310 if (*start) {
311
312
313
314 i = find_next_zero_bit(map, len, i);
315 if (i < len)
316 *end = i - 1;
317 }
318}
319
320
321void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn)
322{
323 u32 gap;
324
325 if (TSN_lt(tsn, map->base_tsn))
326 return;
327
328 if (!TSN_lt(tsn, map->base_tsn + map->len))
329 return;
330
331 gap = tsn - map->base_tsn;
332
333
334 clear_bit(gap, map->tsn_map);
335}
336
337
338__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
339 struct sctp_gap_ack_block *gabs)
340{
341 struct sctp_tsnmap_iter iter;
342 int ngaps = 0;
343
344
345 if (sctp_tsnmap_has_gap(map)) {
346 __u16 start, end;
347 sctp_tsnmap_iter_init(map, &iter);
348 while (sctp_tsnmap_next_gap_ack(map, &iter,
349 &start,
350 &end)) {
351
352 gabs[ngaps].start = htons(start);
353 gabs[ngaps].end = htons(end);
354 ngaps++;
355 if (ngaps >= SCTP_MAX_GABS)
356 break;
357 }
358 }
359 return ngaps;
360}
361
362static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap)
363{
364 unsigned long *new;
365 unsigned long inc;
366 u16 len;
367
368 if (gap >= SCTP_TSN_MAP_SIZE)
369 return 0;
370
371 inc = ALIGN((gap - map->len),BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
372 len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);
373
374 new = kzalloc(len>>3, GFP_ATOMIC);
375 if (!new)
376 return 0;
377
378 bitmap_copy(new, map->tsn_map, map->max_tsn_seen - map->base_tsn);
379 kfree(map->tsn_map);
380 map->tsn_map = new;
381 map->len = len;
382
383 return 1;
384}
385