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60c778b2 | 1 | /* SCTP kernel implementation |
1da177e4 LT |
2 | * (C) Copyright IBM Corp. 2001, 2004 |
3 | * Copyright (c) 1999-2000 Cisco, Inc. | |
4 | * Copyright (c) 1999-2001 Motorola, Inc. | |
5 | * Copyright (c) 2001 Intel Corp. | |
6 | * | |
60c778b2 | 7 | * This file is part of the SCTP kernel implementation |
1da177e4 LT |
8 | * |
9 | * These functions manipulate sctp tsn mapping array. | |
10 | * | |
60c778b2 | 11 | * This SCTP implementation is free software; |
1da177e4 LT |
12 | * you can redistribute it and/or modify it under the terms of |
13 | * the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2, or (at your option) | |
15 | * any later version. | |
16 | * | |
60c778b2 | 17 | * This SCTP implementation is distributed in the hope that it |
1da177e4 LT |
18 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
19 | * ************************ | |
20 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
21 | * See the GNU General Public License for more details. | |
22 | * | |
23 | * You should have received a copy of the GNU General Public License | |
24 | * along with GNU CC; see the file COPYING. If not, write to | |
25 | * the Free Software Foundation, 59 Temple Place - Suite 330, | |
26 | * Boston, MA 02111-1307, USA. | |
27 | * | |
28 | * Please send any bug reports or fixes you make to the | |
29 | * email address(es): | |
30 | * lksctp developers <lksctp-developers@lists.sourceforge.net> | |
31 | * | |
32 | * Or submit a bug report through the following website: | |
33 | * http://www.sf.net/projects/lksctp | |
34 | * | |
35 | * Written or modified by: | |
36 | * La Monte H.P. Yarroll <piggy@acm.org> | |
37 | * Jon Grimm <jgrimm@us.ibm.com> | |
38 | * Karl Knutson <karl@athena.chicago.il.us> | |
39 | * Sridhar Samudrala <sri@us.ibm.com> | |
40 | * | |
41 | * Any bugs reported given to us we will try to fix... any fixes shared will | |
42 | * be incorporated into the next SCTP release. | |
43 | */ | |
44 | ||
5a0e3ad6 | 45 | #include <linux/slab.h> |
1da177e4 | 46 | #include <linux/types.h> |
8e1ee18c | 47 | #include <linux/bitmap.h> |
1da177e4 LT |
48 | #include <net/sctp/sctp.h> |
49 | #include <net/sctp/sm.h> | |
50 | ||
51 | static void sctp_tsnmap_update(struct sctp_tsnmap *map); | |
8e1ee18c VY |
52 | static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off, |
53 | __u16 len, __u16 *start, __u16 *end); | |
54 | static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap); | |
1da177e4 LT |
55 | |
56 | /* Initialize a block of memory as a tsnmap. */ | |
57 | struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *map, __u16 len, | |
8e1ee18c | 58 | __u32 initial_tsn, gfp_t gfp) |
1da177e4 | 59 | { |
8e1ee18c VY |
60 | if (!map->tsn_map) { |
61 | map->tsn_map = kzalloc(len>>3, gfp); | |
62 | if (map->tsn_map == NULL) | |
63 | return NULL; | |
64 | ||
65 | map->len = len; | |
66 | } else { | |
67 | bitmap_zero(map->tsn_map, map->len); | |
68 | } | |
1da177e4 LT |
69 | |
70 | /* Keep track of TSNs represented by tsn_map. */ | |
71 | map->base_tsn = initial_tsn; | |
1da177e4 LT |
72 | map->cumulative_tsn_ack_point = initial_tsn - 1; |
73 | map->max_tsn_seen = map->cumulative_tsn_ack_point; | |
1da177e4 LT |
74 | map->num_dup_tsns = 0; |
75 | ||
76 | return map; | |
77 | } | |
78 | ||
8e1ee18c VY |
79 | void sctp_tsnmap_free(struct sctp_tsnmap *map) |
80 | { | |
81 | map->len = 0; | |
82 | kfree(map->tsn_map); | |
83 | } | |
84 | ||
1da177e4 LT |
85 | /* Test the tracking state of this TSN. |
86 | * Returns: | |
87 | * 0 if the TSN has not yet been seen | |
88 | * >0 if the TSN has been seen (duplicate) | |
89 | * <0 if the TSN is invalid (too large to track) | |
90 | */ | |
91 | int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn) | |
92 | { | |
8e1ee18c VY |
93 | u32 gap; |
94 | ||
95 | /* Check to see if this is an old TSN */ | |
96 | if (TSN_lte(tsn, map->cumulative_tsn_ack_point)) | |
97 | return 1; | |
98 | ||
99 | /* Verify that we can hold this TSN and that it will not | |
100 | * overlfow our map | |
101 | */ | |
102 | if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE)) | |
103 | return -1; | |
1da177e4 LT |
104 | |
105 | /* Calculate the index into the mapping arrays. */ | |
106 | gap = tsn - map->base_tsn; | |
107 | ||
8e1ee18c VY |
108 | /* Check to see if TSN has already been recorded. */ |
109 | if (gap < map->len && test_bit(gap, map->tsn_map)) | |
110 | return 1; | |
1da177e4 | 111 | else |
8e1ee18c | 112 | return 0; |
1da177e4 LT |
113 | } |
114 | ||
115 | ||
116 | /* Mark this TSN as seen. */ | |
8e1ee18c | 117 | int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn) |
1da177e4 | 118 | { |
8e1ee18c | 119 | u16 gap; |
1da177e4 | 120 | |
1da177e4 | 121 | if (TSN_lt(tsn, map->base_tsn)) |
8e1ee18c | 122 | return 0; |
1da177e4 | 123 | |
1da177e4 LT |
124 | gap = tsn - map->base_tsn; |
125 | ||
8e1ee18c VY |
126 | if (gap >= map->len && !sctp_tsnmap_grow(map, gap)) |
127 | return -ENOMEM; | |
1da177e4 | 128 | |
8e1ee18c VY |
129 | if (!sctp_tsnmap_has_gap(map) && gap == 0) { |
130 | /* In this case the map has no gaps and the tsn we are | |
131 | * recording is the next expected tsn. We don't touch | |
132 | * the map but simply bump the values. | |
133 | */ | |
134 | map->max_tsn_seen++; | |
135 | map->cumulative_tsn_ack_point++; | |
136 | map->base_tsn++; | |
137 | } else { | |
138 | /* Either we already have a gap, or about to record a gap, so | |
139 | * have work to do. | |
140 | * | |
141 | * Bump the max. | |
142 | */ | |
143 | if (TSN_lt(map->max_tsn_seen, tsn)) | |
144 | map->max_tsn_seen = tsn; | |
145 | ||
146 | /* Mark the TSN as received. */ | |
147 | set_bit(gap, map->tsn_map); | |
148 | ||
149 | /* Go fixup any internal TSN mapping variables including | |
150 | * cumulative_tsn_ack_point. | |
151 | */ | |
152 | sctp_tsnmap_update(map); | |
153 | } | |
154 | ||
155 | return 0; | |
1da177e4 LT |
156 | } |
157 | ||
158 | ||
159 | /* Initialize a Gap Ack Block iterator from memory being provided. */ | |
160 | SCTP_STATIC void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map, | |
161 | struct sctp_tsnmap_iter *iter) | |
162 | { | |
163 | /* Only start looking one past the Cumulative TSN Ack Point. */ | |
164 | iter->start = map->cumulative_tsn_ack_point + 1; | |
165 | } | |
166 | ||
167 | /* Get the next Gap Ack Blocks. Returns 0 if there was not another block | |
168 | * to get. | |
169 | */ | |
170 | SCTP_STATIC int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map, | |
171 | struct sctp_tsnmap_iter *iter, | |
172 | __u16 *start, __u16 *end) | |
173 | { | |
8e1ee18c VY |
174 | int ended = 0; |
175 | __u16 start_ = 0, end_ = 0, offset; | |
1da177e4 LT |
176 | |
177 | /* If there are no more gap acks possible, get out fast. */ | |
178 | if (TSN_lte(map->max_tsn_seen, iter->start)) | |
179 | return 0; | |
180 | ||
8e1ee18c VY |
181 | offset = iter->start - map->base_tsn; |
182 | sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len, | |
183 | &start_, &end_); | |
1da177e4 | 184 | |
8e1ee18c VY |
185 | /* The Gap Ack Block happens to end at the end of the map. */ |
186 | if (start_ && !end_) | |
187 | end_ = map->len - 1; | |
1da177e4 LT |
188 | |
189 | /* If we found a Gap Ack Block, return the start and end and | |
190 | * bump the iterator forward. | |
191 | */ | |
8e1ee18c | 192 | if (end_) { |
1da177e4 | 193 | /* Fix up the start and end based on the |
8e1ee18c | 194 | * Cumulative TSN Ack which is always 1 behind base. |
1da177e4 | 195 | */ |
8e1ee18c VY |
196 | *start = start_ + 1; |
197 | *end = end_ + 1; | |
1da177e4 LT |
198 | |
199 | /* Move the iterator forward. */ | |
200 | iter->start = map->cumulative_tsn_ack_point + *end + 1; | |
8e1ee18c | 201 | ended = 1; |
1da177e4 LT |
202 | } |
203 | ||
204 | return ended; | |
205 | } | |
206 | ||
207 | /* Mark this and any lower TSN as seen. */ | |
208 | void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn) | |
209 | { | |
8e1ee18c | 210 | u32 gap; |
1da177e4 | 211 | |
1da177e4 LT |
212 | if (TSN_lt(tsn, map->base_tsn)) |
213 | return; | |
8e1ee18c | 214 | if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE)) |
1da177e4 LT |
215 | return; |
216 | ||
217 | /* Bump the max. */ | |
218 | if (TSN_lt(map->max_tsn_seen, tsn)) | |
219 | map->max_tsn_seen = tsn; | |
220 | ||
1da177e4 LT |
221 | gap = tsn - map->base_tsn + 1; |
222 | ||
8e1ee18c VY |
223 | map->base_tsn += gap; |
224 | map->cumulative_tsn_ack_point += gap; | |
225 | if (gap >= map->len) { | |
226 | /* If our gap is larger then the map size, just | |
227 | * zero out the map. | |
228 | */ | |
229 | bitmap_zero(map->tsn_map, map->len); | |
230 | } else { | |
025dfdaf | 231 | /* If the gap is smaller than the map size, |
8e1ee18c VY |
232 | * shift the map by 'gap' bits and update further. |
233 | */ | |
234 | bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len); | |
235 | sctp_tsnmap_update(map); | |
1da177e4 | 236 | } |
1da177e4 LT |
237 | } |
238 | ||
239 | /******************************************************************** | |
240 | * 2nd Level Abstractions | |
241 | ********************************************************************/ | |
242 | ||
243 | /* This private helper function updates the tsnmap buffers and | |
244 | * the Cumulative TSN Ack Point. | |
245 | */ | |
246 | static void sctp_tsnmap_update(struct sctp_tsnmap *map) | |
247 | { | |
8e1ee18c VY |
248 | u16 len; |
249 | unsigned long zero_bit; | |
250 | ||
251 | ||
252 | len = map->max_tsn_seen - map->cumulative_tsn_ack_point; | |
253 | zero_bit = find_first_zero_bit(map->tsn_map, len); | |
254 | if (!zero_bit) | |
255 | return; /* The first 0-bit is bit 0. nothing to do */ | |
256 | ||
257 | map->base_tsn += zero_bit; | |
258 | map->cumulative_tsn_ack_point += zero_bit; | |
1da177e4 | 259 | |
8e1ee18c | 260 | bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len); |
1da177e4 LT |
261 | } |
262 | ||
263 | /* How many data chunks are we missing from our peer? | |
264 | */ | |
265 | __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map) | |
266 | { | |
267 | __u32 cum_tsn = map->cumulative_tsn_ack_point; | |
268 | __u32 max_tsn = map->max_tsn_seen; | |
269 | __u32 base_tsn = map->base_tsn; | |
270 | __u16 pending_data; | |
8e1ee18c | 271 | u32 gap, i; |
1da177e4 LT |
272 | |
273 | pending_data = max_tsn - cum_tsn; | |
274 | gap = max_tsn - base_tsn; | |
275 | ||
8e1ee18c | 276 | if (gap == 0 || gap >= map->len) |
1da177e4 LT |
277 | goto out; |
278 | ||
8e1ee18c VY |
279 | for (i = 0; i < gap+1; i++) { |
280 | if (test_bit(i, map->tsn_map)) | |
1da177e4 LT |
281 | pending_data--; |
282 | } | |
283 | ||
1da177e4 LT |
284 | out: |
285 | return pending_data; | |
286 | } | |
287 | ||
288 | /* This is a private helper for finding Gap Ack Blocks. It searches a | |
289 | * single array for the start and end of a Gap Ack Block. | |
290 | * | |
291 | * The flags "started" and "ended" tell is if we found the beginning | |
292 | * or (respectively) the end of a Gap Ack Block. | |
293 | */ | |
8e1ee18c VY |
294 | static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off, |
295 | __u16 len, __u16 *start, __u16 *end) | |
1da177e4 LT |
296 | { |
297 | int i = off; | |
298 | ||
299 | /* Look through the entire array, but break out | |
300 | * early if we have found the end of the Gap Ack Block. | |
301 | */ | |
302 | ||
303 | /* Also, stop looking past the maximum TSN seen. */ | |
304 | ||
305 | /* Look for the start. */ | |
8e1ee18c VY |
306 | i = find_next_bit(map, len, off); |
307 | if (i < len) | |
308 | *start = i; | |
1da177e4 LT |
309 | |
310 | /* Look for the end. */ | |
8e1ee18c | 311 | if (*start) { |
1da177e4 LT |
312 | /* We have found the start, let's find the |
313 | * end. If we find the end, break out. | |
314 | */ | |
8e1ee18c VY |
315 | i = find_next_zero_bit(map, len, i); |
316 | if (i < len) | |
317 | *end = i - 1; | |
1da177e4 LT |
318 | } |
319 | } | |
320 | ||
321 | /* Renege that we have seen a TSN. */ | |
322 | void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn) | |
323 | { | |
8e1ee18c | 324 | u32 gap; |
1da177e4 LT |
325 | |
326 | if (TSN_lt(tsn, map->base_tsn)) | |
327 | return; | |
8e1ee18c VY |
328 | /* Assert: TSN is in range. */ |
329 | if (!TSN_lt(tsn, map->base_tsn + map->len)) | |
1da177e4 LT |
330 | return; |
331 | ||
1da177e4 LT |
332 | gap = tsn - map->base_tsn; |
333 | ||
334 | /* Pretend we never saw the TSN. */ | |
8e1ee18c | 335 | clear_bit(gap, map->tsn_map); |
1da177e4 LT |
336 | } |
337 | ||
338 | /* How many gap ack blocks do we have recorded? */ | |
02015180 VY |
339 | __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map, |
340 | struct sctp_gap_ack_block *gabs) | |
1da177e4 LT |
341 | { |
342 | struct sctp_tsnmap_iter iter; | |
02015180 | 343 | int ngaps = 0; |
1da177e4 LT |
344 | |
345 | /* Refresh the gap ack information. */ | |
346 | if (sctp_tsnmap_has_gap(map)) { | |
9f81bcd9 | 347 | __u16 start, end; |
1da177e4 LT |
348 | sctp_tsnmap_iter_init(map, &iter); |
349 | while (sctp_tsnmap_next_gap_ack(map, &iter, | |
9f81bcd9 AV |
350 | &start, |
351 | &end)) { | |
1da177e4 | 352 | |
02015180 VY |
353 | gabs[ngaps].start = htons(start); |
354 | gabs[ngaps].end = htons(end); | |
355 | ngaps++; | |
356 | if (ngaps >= SCTP_MAX_GABS) | |
1da177e4 LT |
357 | break; |
358 | } | |
359 | } | |
02015180 | 360 | return ngaps; |
1da177e4 | 361 | } |
8e1ee18c VY |
362 | |
363 | static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap) | |
364 | { | |
365 | unsigned long *new; | |
366 | unsigned long inc; | |
367 | u16 len; | |
368 | ||
369 | if (gap >= SCTP_TSN_MAP_SIZE) | |
370 | return 0; | |
371 | ||
372 | inc = ALIGN((gap - map->len),BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT; | |
373 | len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE); | |
374 | ||
375 | new = kzalloc(len>>3, GFP_ATOMIC); | |
376 | if (!new) | |
377 | return 0; | |
378 | ||
379 | bitmap_copy(new, map->tsn_map, map->max_tsn_seen - map->base_tsn); | |
380 | kfree(map->tsn_map); | |
381 | map->tsn_map = new; | |
382 | map->len = len; | |
383 | ||
384 | return 1; | |
385 | } |