1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Copyright (C) B.A.T.M.A.N. contributors: |
3 | * |
4 | * Edo Monticelli, Antonio Quartulli |
5 | */ |
6 | |
7 | #include "tp_meter.h" |
8 | #include "main.h" |
9 | |
10 | #include <linux/atomic.h> |
11 | #include <linux/build_bug.h> |
12 | #include <linux/byteorder/generic.h> |
13 | #include <linux/cache.h> |
14 | #include <linux/compiler.h> |
15 | #include <linux/container_of.h> |
16 | #include <linux/err.h> |
17 | #include <linux/etherdevice.h> |
18 | #include <linux/gfp.h> |
19 | #include <linux/if_ether.h> |
20 | #include <linux/init.h> |
21 | #include <linux/jiffies.h> |
22 | #include <linux/kref.h> |
23 | #include <linux/kthread.h> |
24 | #include <linux/limits.h> |
25 | #include <linux/list.h> |
26 | #include <linux/minmax.h> |
27 | #include <linux/netdevice.h> |
28 | #include <linux/param.h> |
29 | #include <linux/printk.h> |
30 | #include <linux/random.h> |
31 | #include <linux/rculist.h> |
32 | #include <linux/rcupdate.h> |
33 | #include <linux/sched.h> |
34 | #include <linux/skbuff.h> |
35 | #include <linux/slab.h> |
36 | #include <linux/spinlock.h> |
37 | #include <linux/stddef.h> |
38 | #include <linux/string.h> |
39 | #include <linux/timer.h> |
40 | #include <linux/wait.h> |
41 | #include <linux/workqueue.h> |
42 | #include <uapi/linux/batadv_packet.h> |
43 | #include <uapi/linux/batman_adv.h> |
44 | |
45 | #include "hard-interface.h" |
46 | #include "log.h" |
47 | #include "netlink.h" |
48 | #include "originator.h" |
49 | #include "send.h" |
50 | |
51 | /** |
52 | * BATADV_TP_DEF_TEST_LENGTH - Default test length if not specified by the user |
53 | * in milliseconds |
54 | */ |
55 | #define BATADV_TP_DEF_TEST_LENGTH 10000 |
56 | |
57 | /** |
58 | * BATADV_TP_AWND - Advertised window by the receiver (in bytes) |
59 | */ |
60 | #define BATADV_TP_AWND 0x20000000 |
61 | |
62 | /** |
63 | * BATADV_TP_RECV_TIMEOUT - Receiver activity timeout. If the receiver does not |
64 | * get anything for such amount of milliseconds, the connection is killed |
65 | */ |
66 | #define BATADV_TP_RECV_TIMEOUT 1000 |
67 | |
68 | /** |
69 | * BATADV_TP_MAX_RTO - Maximum sender timeout. If the sender RTO gets beyond |
70 | * such amount of milliseconds, the receiver is considered unreachable and the |
71 | * connection is killed |
72 | */ |
73 | #define BATADV_TP_MAX_RTO 30000 |
74 | |
75 | /** |
76 | * BATADV_TP_FIRST_SEQ - First seqno of each session. The number is rather high |
77 | * in order to immediately trigger a wrap around (test purposes) |
78 | */ |
79 | #define BATADV_TP_FIRST_SEQ ((u32)-1 - 2000) |
80 | |
81 | /** |
82 | * BATADV_TP_PLEN - length of the payload (data after the batadv_unicast header) |
83 | * to simulate |
84 | */ |
85 | #define BATADV_TP_PLEN (BATADV_TP_PACKET_LEN - ETH_HLEN - \ |
86 | sizeof(struct batadv_unicast_packet)) |
87 | |
88 | static u8 batadv_tp_prerandom[4096] __read_mostly; |
89 | |
90 | /** |
91 | * batadv_tp_session_cookie() - generate session cookie based on session ids |
92 | * @session: TP session identifier |
93 | * @icmp_uid: icmp pseudo uid of the tp session |
94 | * |
95 | * Return: 32 bit tp_meter session cookie |
96 | */ |
97 | static u32 batadv_tp_session_cookie(const u8 session[2], u8 icmp_uid) |
98 | { |
99 | u32 cookie; |
100 | |
101 | cookie = icmp_uid << 16; |
102 | cookie |= session[0] << 8; |
103 | cookie |= session[1]; |
104 | |
105 | return cookie; |
106 | } |
107 | |
108 | /** |
109 | * batadv_tp_cwnd() - compute the new cwnd size |
110 | * @base: base cwnd size value |
111 | * @increment: the value to add to base to get the new size |
112 | * @min: minimum cwnd value (usually MSS) |
113 | * |
114 | * Return the new cwnd size and ensure it does not exceed the Advertised |
115 | * Receiver Window size. It is wrapped around safely. |
116 | * For details refer to Section 3.1 of RFC5681 |
117 | * |
118 | * Return: new congestion window size in bytes |
119 | */ |
120 | static u32 batadv_tp_cwnd(u32 base, u32 increment, u32 min) |
121 | { |
122 | u32 new_size = base + increment; |
123 | |
124 | /* check for wrap-around */ |
125 | if (new_size < base) |
126 | new_size = (u32)ULONG_MAX; |
127 | |
128 | new_size = min_t(u32, new_size, BATADV_TP_AWND); |
129 | |
130 | return max_t(u32, new_size, min); |
131 | } |
132 | |
133 | /** |
134 | * batadv_tp_update_cwnd() - update the Congestion Windows |
135 | * @tp_vars: the private data of the current TP meter session |
136 | * @mss: maximum segment size of transmission |
137 | * |
138 | * 1) if the session is in Slow Start, the CWND has to be increased by 1 |
139 | * MSS every unique received ACK |
140 | * 2) if the session is in Congestion Avoidance, the CWND has to be |
141 | * increased by MSS * MSS / CWND for every unique received ACK |
142 | */ |
143 | static void batadv_tp_update_cwnd(struct batadv_tp_vars *tp_vars, u32 mss) |
144 | { |
145 | spin_lock_bh(lock: &tp_vars->cwnd_lock); |
146 | |
147 | /* slow start... */ |
148 | if (tp_vars->cwnd <= tp_vars->ss_threshold) { |
149 | tp_vars->dec_cwnd = 0; |
150 | tp_vars->cwnd = batadv_tp_cwnd(base: tp_vars->cwnd, increment: mss, min: mss); |
151 | spin_unlock_bh(lock: &tp_vars->cwnd_lock); |
152 | return; |
153 | } |
154 | |
155 | /* increment CWND at least of 1 (section 3.1 of RFC5681) */ |
156 | tp_vars->dec_cwnd += max_t(u32, 1U << 3, |
157 | ((mss * mss) << 6) / (tp_vars->cwnd << 3)); |
158 | if (tp_vars->dec_cwnd < (mss << 3)) { |
159 | spin_unlock_bh(lock: &tp_vars->cwnd_lock); |
160 | return; |
161 | } |
162 | |
163 | tp_vars->cwnd = batadv_tp_cwnd(base: tp_vars->cwnd, increment: mss, min: mss); |
164 | tp_vars->dec_cwnd = 0; |
165 | |
166 | spin_unlock_bh(lock: &tp_vars->cwnd_lock); |
167 | } |
168 | |
169 | /** |
170 | * batadv_tp_update_rto() - calculate new retransmission timeout |
171 | * @tp_vars: the private data of the current TP meter session |
172 | * @new_rtt: new roundtrip time in msec |
173 | */ |
174 | static void batadv_tp_update_rto(struct batadv_tp_vars *tp_vars, |
175 | u32 new_rtt) |
176 | { |
177 | long m = new_rtt; |
178 | |
179 | /* RTT update |
180 | * Details in Section 2.2 and 2.3 of RFC6298 |
181 | * |
182 | * It's tricky to understand. Don't lose hair please. |
183 | * Inspired by tcp_rtt_estimator() tcp_input.c |
184 | */ |
185 | if (tp_vars->srtt != 0) { |
186 | m -= (tp_vars->srtt >> 3); /* m is now error in rtt est */ |
187 | tp_vars->srtt += m; /* rtt = 7/8 srtt + 1/8 new */ |
188 | if (m < 0) |
189 | m = -m; |
190 | |
191 | m -= (tp_vars->rttvar >> 2); |
192 | tp_vars->rttvar += m; /* mdev ~= 3/4 rttvar + 1/4 new */ |
193 | } else { |
194 | /* first measure getting in */ |
195 | tp_vars->srtt = m << 3; /* take the measured time to be srtt */ |
196 | tp_vars->rttvar = m << 1; /* new_rtt / 2 */ |
197 | } |
198 | |
199 | /* rto = srtt + 4 * rttvar. |
200 | * rttvar is scaled by 4, therefore doesn't need to be multiplied |
201 | */ |
202 | tp_vars->rto = (tp_vars->srtt >> 3) + tp_vars->rttvar; |
203 | } |
204 | |
205 | /** |
206 | * batadv_tp_batctl_notify() - send client status result to client |
207 | * @reason: reason for tp meter session stop |
208 | * @dst: destination of tp_meter session |
209 | * @bat_priv: the bat priv with all the soft interface information |
210 | * @start_time: start of transmission in jiffies |
211 | * @total_sent: bytes acked to the receiver |
212 | * @cookie: cookie of tp_meter session |
213 | */ |
214 | static void batadv_tp_batctl_notify(enum batadv_tp_meter_reason reason, |
215 | const u8 *dst, struct batadv_priv *bat_priv, |
216 | unsigned long start_time, u64 total_sent, |
217 | u32 cookie) |
218 | { |
219 | u32 test_time; |
220 | u8 result; |
221 | u32 total_bytes; |
222 | |
223 | if (!batadv_tp_is_error(reason)) { |
224 | result = BATADV_TP_REASON_COMPLETE; |
225 | test_time = jiffies_to_msecs(j: jiffies - start_time); |
226 | total_bytes = total_sent; |
227 | } else { |
228 | result = reason; |
229 | test_time = 0; |
230 | total_bytes = 0; |
231 | } |
232 | |
233 | batadv_netlink_tpmeter_notify(bat_priv, dst, result, test_time, |
234 | total_bytes, cookie); |
235 | } |
236 | |
237 | /** |
238 | * batadv_tp_batctl_error_notify() - send client error result to client |
239 | * @reason: reason for tp meter session stop |
240 | * @dst: destination of tp_meter session |
241 | * @bat_priv: the bat priv with all the soft interface information |
242 | * @cookie: cookie of tp_meter session |
243 | */ |
244 | static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason, |
245 | const u8 *dst, |
246 | struct batadv_priv *bat_priv, |
247 | u32 cookie) |
248 | { |
249 | batadv_tp_batctl_notify(reason, dst, bat_priv, start_time: 0, total_sent: 0, cookie); |
250 | } |
251 | |
252 | /** |
253 | * batadv_tp_list_find() - find a tp_vars object in the global list |
254 | * @bat_priv: the bat priv with all the soft interface information |
255 | * @dst: the other endpoint MAC address to look for |
256 | * |
257 | * Look for a tp_vars object matching dst as end_point and return it after |
258 | * having increment the refcounter. Return NULL is not found |
259 | * |
260 | * Return: matching tp_vars or NULL when no tp_vars with @dst was found |
261 | */ |
262 | static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv, |
263 | const u8 *dst) |
264 | { |
265 | struct batadv_tp_vars *pos, *tp_vars = NULL; |
266 | |
267 | rcu_read_lock(); |
268 | hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) { |
269 | if (!batadv_compare_eth(data1: pos->other_end, data2: dst)) |
270 | continue; |
271 | |
272 | /* most of the time this function is invoked during the normal |
273 | * process..it makes sens to pay more when the session is |
274 | * finished and to speed the process up during the measurement |
275 | */ |
276 | if (unlikely(!kref_get_unless_zero(&pos->refcount))) |
277 | continue; |
278 | |
279 | tp_vars = pos; |
280 | break; |
281 | } |
282 | rcu_read_unlock(); |
283 | |
284 | return tp_vars; |
285 | } |
286 | |
287 | /** |
288 | * batadv_tp_list_find_session() - find tp_vars session object in the global |
289 | * list |
290 | * @bat_priv: the bat priv with all the soft interface information |
291 | * @dst: the other endpoint MAC address to look for |
292 | * @session: session identifier |
293 | * |
294 | * Look for a tp_vars object matching dst as end_point, session as tp meter |
295 | * session and return it after having increment the refcounter. Return NULL |
296 | * is not found |
297 | * |
298 | * Return: matching tp_vars or NULL when no tp_vars was found |
299 | */ |
300 | static struct batadv_tp_vars * |
301 | batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst, |
302 | const u8 *session) |
303 | { |
304 | struct batadv_tp_vars *pos, *tp_vars = NULL; |
305 | |
306 | rcu_read_lock(); |
307 | hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) { |
308 | if (!batadv_compare_eth(data1: pos->other_end, data2: dst)) |
309 | continue; |
310 | |
311 | if (memcmp(p: pos->session, q: session, size: sizeof(pos->session)) != 0) |
312 | continue; |
313 | |
314 | /* most of the time this function is invoked during the normal |
315 | * process..it makes sense to pay more when the session is |
316 | * finished and to speed the process up during the measurement |
317 | */ |
318 | if (unlikely(!kref_get_unless_zero(&pos->refcount))) |
319 | continue; |
320 | |
321 | tp_vars = pos; |
322 | break; |
323 | } |
324 | rcu_read_unlock(); |
325 | |
326 | return tp_vars; |
327 | } |
328 | |
329 | /** |
330 | * batadv_tp_vars_release() - release batadv_tp_vars from lists and queue for |
331 | * free after rcu grace period |
332 | * @ref: kref pointer of the batadv_tp_vars |
333 | */ |
334 | static void batadv_tp_vars_release(struct kref *ref) |
335 | { |
336 | struct batadv_tp_vars *tp_vars; |
337 | struct batadv_tp_unacked *un, *safe; |
338 | |
339 | tp_vars = container_of(ref, struct batadv_tp_vars, refcount); |
340 | |
341 | /* lock should not be needed because this object is now out of any |
342 | * context! |
343 | */ |
344 | spin_lock_bh(lock: &tp_vars->unacked_lock); |
345 | list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { |
346 | list_del(entry: &un->list); |
347 | kfree(objp: un); |
348 | } |
349 | spin_unlock_bh(lock: &tp_vars->unacked_lock); |
350 | |
351 | kfree_rcu(tp_vars, rcu); |
352 | } |
353 | |
354 | /** |
355 | * batadv_tp_vars_put() - decrement the batadv_tp_vars refcounter and possibly |
356 | * release it |
357 | * @tp_vars: the private data of the current TP meter session to be free'd |
358 | */ |
359 | static void batadv_tp_vars_put(struct batadv_tp_vars *tp_vars) |
360 | { |
361 | if (!tp_vars) |
362 | return; |
363 | |
364 | kref_put(kref: &tp_vars->refcount, release: batadv_tp_vars_release); |
365 | } |
366 | |
367 | /** |
368 | * batadv_tp_sender_cleanup() - cleanup sender data and drop and timer |
369 | * @bat_priv: the bat priv with all the soft interface information |
370 | * @tp_vars: the private data of the current TP meter session to cleanup |
371 | */ |
372 | static void batadv_tp_sender_cleanup(struct batadv_priv *bat_priv, |
373 | struct batadv_tp_vars *tp_vars) |
374 | { |
375 | cancel_delayed_work(dwork: &tp_vars->finish_work); |
376 | |
377 | spin_lock_bh(lock: &tp_vars->bat_priv->tp_list_lock); |
378 | hlist_del_rcu(n: &tp_vars->list); |
379 | spin_unlock_bh(lock: &tp_vars->bat_priv->tp_list_lock); |
380 | |
381 | /* drop list reference */ |
382 | batadv_tp_vars_put(tp_vars); |
383 | |
384 | atomic_dec(v: &tp_vars->bat_priv->tp_num); |
385 | |
386 | /* kill the timer and remove its reference */ |
387 | del_timer_sync(timer: &tp_vars->timer); |
388 | /* the worker might have rearmed itself therefore we kill it again. Note |
389 | * that if the worker should run again before invoking the following |
390 | * del_timer(), it would not re-arm itself once again because the status |
391 | * is OFF now |
392 | */ |
393 | del_timer(timer: &tp_vars->timer); |
394 | batadv_tp_vars_put(tp_vars); |
395 | } |
396 | |
397 | /** |
398 | * batadv_tp_sender_end() - print info about ended session and inform client |
399 | * @bat_priv: the bat priv with all the soft interface information |
400 | * @tp_vars: the private data of the current TP meter session |
401 | */ |
402 | static void batadv_tp_sender_end(struct batadv_priv *bat_priv, |
403 | struct batadv_tp_vars *tp_vars) |
404 | { |
405 | u32 session_cookie; |
406 | |
407 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
408 | "Test towards %pM finished..shutting down (reason=%d)\n" , |
409 | tp_vars->other_end, tp_vars->reason); |
410 | |
411 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
412 | "Last timing stats: SRTT=%ums RTTVAR=%ums RTO=%ums\n" , |
413 | tp_vars->srtt >> 3, tp_vars->rttvar >> 2, tp_vars->rto); |
414 | |
415 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
416 | "Final values: cwnd=%u ss_threshold=%u\n" , |
417 | tp_vars->cwnd, tp_vars->ss_threshold); |
418 | |
419 | session_cookie = batadv_tp_session_cookie(session: tp_vars->session, |
420 | icmp_uid: tp_vars->icmp_uid); |
421 | |
422 | batadv_tp_batctl_notify(reason: tp_vars->reason, |
423 | dst: tp_vars->other_end, |
424 | bat_priv, |
425 | start_time: tp_vars->start_time, |
426 | total_sent: atomic64_read(v: &tp_vars->tot_sent), |
427 | cookie: session_cookie); |
428 | } |
429 | |
430 | /** |
431 | * batadv_tp_sender_shutdown() - let sender thread/timer stop gracefully |
432 | * @tp_vars: the private data of the current TP meter session |
433 | * @reason: reason for tp meter session stop |
434 | */ |
435 | static void batadv_tp_sender_shutdown(struct batadv_tp_vars *tp_vars, |
436 | enum batadv_tp_meter_reason reason) |
437 | { |
438 | if (!atomic_dec_and_test(v: &tp_vars->sending)) |
439 | return; |
440 | |
441 | tp_vars->reason = reason; |
442 | } |
443 | |
444 | /** |
445 | * batadv_tp_sender_finish() - stop sender session after test_length was reached |
446 | * @work: delayed work reference of the related tp_vars |
447 | */ |
448 | static void batadv_tp_sender_finish(struct work_struct *work) |
449 | { |
450 | struct delayed_work *delayed_work; |
451 | struct batadv_tp_vars *tp_vars; |
452 | |
453 | delayed_work = to_delayed_work(work); |
454 | tp_vars = container_of(delayed_work, struct batadv_tp_vars, |
455 | finish_work); |
456 | |
457 | batadv_tp_sender_shutdown(tp_vars, reason: BATADV_TP_REASON_COMPLETE); |
458 | } |
459 | |
460 | /** |
461 | * batadv_tp_reset_sender_timer() - reschedule the sender timer |
462 | * @tp_vars: the private TP meter data for this session |
463 | * |
464 | * Reschedule the timer using tp_vars->rto as delay |
465 | */ |
466 | static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars) |
467 | { |
468 | /* most of the time this function is invoked while normal packet |
469 | * reception... |
470 | */ |
471 | if (unlikely(atomic_read(&tp_vars->sending) == 0)) |
472 | /* timer ref will be dropped in batadv_tp_sender_cleanup */ |
473 | return; |
474 | |
475 | mod_timer(timer: &tp_vars->timer, expires: jiffies + msecs_to_jiffies(m: tp_vars->rto)); |
476 | } |
477 | |
478 | /** |
479 | * batadv_tp_sender_timeout() - timer that fires in case of packet loss |
480 | * @t: address to timer_list inside tp_vars |
481 | * |
482 | * If fired it means that there was packet loss. |
483 | * Switch to Slow Start, set the ss_threshold to half of the current cwnd and |
484 | * reset the cwnd to 3*MSS |
485 | */ |
486 | static void batadv_tp_sender_timeout(struct timer_list *t) |
487 | { |
488 | struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer); |
489 | struct batadv_priv *bat_priv = tp_vars->bat_priv; |
490 | |
491 | if (atomic_read(v: &tp_vars->sending) == 0) |
492 | return; |
493 | |
494 | /* if the user waited long enough...shutdown the test */ |
495 | if (unlikely(tp_vars->rto >= BATADV_TP_MAX_RTO)) { |
496 | batadv_tp_sender_shutdown(tp_vars, |
497 | reason: BATADV_TP_REASON_DST_UNREACHABLE); |
498 | return; |
499 | } |
500 | |
501 | /* RTO exponential backoff |
502 | * Details in Section 5.5 of RFC6298 |
503 | */ |
504 | tp_vars->rto <<= 1; |
505 | |
506 | spin_lock_bh(lock: &tp_vars->cwnd_lock); |
507 | |
508 | tp_vars->ss_threshold = tp_vars->cwnd >> 1; |
509 | if (tp_vars->ss_threshold < BATADV_TP_PLEN * 2) |
510 | tp_vars->ss_threshold = BATADV_TP_PLEN * 2; |
511 | |
512 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
513 | "Meter: RTO fired during test towards %pM! cwnd=%u new ss_thr=%u, resetting last_sent to %u\n" , |
514 | tp_vars->other_end, tp_vars->cwnd, tp_vars->ss_threshold, |
515 | atomic_read(&tp_vars->last_acked)); |
516 | |
517 | tp_vars->cwnd = BATADV_TP_PLEN * 3; |
518 | |
519 | spin_unlock_bh(lock: &tp_vars->cwnd_lock); |
520 | |
521 | /* resend the non-ACKed packets.. */ |
522 | tp_vars->last_sent = atomic_read(v: &tp_vars->last_acked); |
523 | wake_up(&tp_vars->more_bytes); |
524 | |
525 | batadv_tp_reset_sender_timer(tp_vars); |
526 | } |
527 | |
528 | /** |
529 | * batadv_tp_fill_prerandom() - Fill buffer with prefetched random bytes |
530 | * @tp_vars: the private TP meter data for this session |
531 | * @buf: Buffer to fill with bytes |
532 | * @nbytes: amount of pseudorandom bytes |
533 | */ |
534 | static void batadv_tp_fill_prerandom(struct batadv_tp_vars *tp_vars, |
535 | u8 *buf, size_t nbytes) |
536 | { |
537 | u32 local_offset; |
538 | size_t bytes_inbuf; |
539 | size_t to_copy; |
540 | size_t pos = 0; |
541 | |
542 | spin_lock_bh(lock: &tp_vars->prerandom_lock); |
543 | local_offset = tp_vars->prerandom_offset; |
544 | tp_vars->prerandom_offset += nbytes; |
545 | tp_vars->prerandom_offset %= sizeof(batadv_tp_prerandom); |
546 | spin_unlock_bh(lock: &tp_vars->prerandom_lock); |
547 | |
548 | while (nbytes) { |
549 | local_offset %= sizeof(batadv_tp_prerandom); |
550 | bytes_inbuf = sizeof(batadv_tp_prerandom) - local_offset; |
551 | to_copy = min(nbytes, bytes_inbuf); |
552 | |
553 | memcpy(&buf[pos], &batadv_tp_prerandom[local_offset], to_copy); |
554 | pos += to_copy; |
555 | nbytes -= to_copy; |
556 | local_offset = 0; |
557 | } |
558 | } |
559 | |
560 | /** |
561 | * batadv_tp_send_msg() - send a single message |
562 | * @tp_vars: the private TP meter data for this session |
563 | * @src: source mac address |
564 | * @orig_node: the originator of the destination |
565 | * @seqno: sequence number of this packet |
566 | * @len: length of the entire packet |
567 | * @session: session identifier |
568 | * @uid: local ICMP "socket" index |
569 | * @timestamp: timestamp in jiffies which is replied in ack |
570 | * |
571 | * Create and send a single TP Meter message. |
572 | * |
573 | * Return: 0 on success, BATADV_TP_REASON_DST_UNREACHABLE if the destination is |
574 | * not reachable, BATADV_TP_REASON_MEMORY_ERROR if the packet couldn't be |
575 | * allocated |
576 | */ |
577 | static int batadv_tp_send_msg(struct batadv_tp_vars *tp_vars, const u8 *src, |
578 | struct batadv_orig_node *orig_node, |
579 | u32 seqno, size_t len, const u8 *session, |
580 | int uid, u32 timestamp) |
581 | { |
582 | struct batadv_icmp_tp_packet *icmp; |
583 | struct sk_buff *skb; |
584 | int r; |
585 | u8 *data; |
586 | size_t data_len; |
587 | |
588 | skb = netdev_alloc_skb_ip_align(NULL, length: len + ETH_HLEN); |
589 | if (unlikely(!skb)) |
590 | return BATADV_TP_REASON_MEMORY_ERROR; |
591 | |
592 | skb_reserve(skb, ETH_HLEN); |
593 | icmp = skb_put(skb, len: sizeof(*icmp)); |
594 | |
595 | /* fill the icmp header */ |
596 | ether_addr_copy(dst: icmp->dst, src: orig_node->orig); |
597 | ether_addr_copy(dst: icmp->orig, src); |
598 | icmp->version = BATADV_COMPAT_VERSION; |
599 | icmp->packet_type = BATADV_ICMP; |
600 | icmp->ttl = BATADV_TTL; |
601 | icmp->msg_type = BATADV_TP; |
602 | icmp->uid = uid; |
603 | |
604 | icmp->subtype = BATADV_TP_MSG; |
605 | memcpy(icmp->session, session, sizeof(icmp->session)); |
606 | icmp->seqno = htonl(seqno); |
607 | icmp->timestamp = htonl(timestamp); |
608 | |
609 | data_len = len - sizeof(*icmp); |
610 | data = skb_put(skb, len: data_len); |
611 | batadv_tp_fill_prerandom(tp_vars, buf: data, nbytes: data_len); |
612 | |
613 | r = batadv_send_skb_to_orig(skb, orig_node, NULL); |
614 | if (r == NET_XMIT_SUCCESS) |
615 | return 0; |
616 | |
617 | return BATADV_TP_REASON_CANT_SEND; |
618 | } |
619 | |
620 | /** |
621 | * batadv_tp_recv_ack() - ACK receiving function |
622 | * @bat_priv: the bat priv with all the soft interface information |
623 | * @skb: the buffer containing the received packet |
624 | * |
625 | * Process a received TP ACK packet |
626 | */ |
627 | static void batadv_tp_recv_ack(struct batadv_priv *bat_priv, |
628 | const struct sk_buff *skb) |
629 | { |
630 | struct batadv_hard_iface *primary_if = NULL; |
631 | struct batadv_orig_node *orig_node = NULL; |
632 | const struct batadv_icmp_tp_packet *icmp; |
633 | struct batadv_tp_vars *tp_vars; |
634 | const unsigned char *dev_addr; |
635 | size_t packet_len, mss; |
636 | u32 rtt, recv_ack, cwnd; |
637 | |
638 | packet_len = BATADV_TP_PLEN; |
639 | mss = BATADV_TP_PLEN; |
640 | packet_len += sizeof(struct batadv_unicast_packet); |
641 | |
642 | icmp = (struct batadv_icmp_tp_packet *)skb->data; |
643 | |
644 | /* find the tp_vars */ |
645 | tp_vars = batadv_tp_list_find_session(bat_priv, dst: icmp->orig, |
646 | session: icmp->session); |
647 | if (unlikely(!tp_vars)) |
648 | return; |
649 | |
650 | if (unlikely(atomic_read(&tp_vars->sending) == 0)) |
651 | goto out; |
652 | |
653 | /* old ACK? silently drop it.. */ |
654 | if (batadv_seq_before(ntohl(icmp->seqno), |
655 | (u32)atomic_read(&tp_vars->last_acked))) |
656 | goto out; |
657 | |
658 | primary_if = batadv_primary_if_get_selected(bat_priv); |
659 | if (unlikely(!primary_if)) |
660 | goto out; |
661 | |
662 | orig_node = batadv_orig_hash_find(bat_priv, data: icmp->orig); |
663 | if (unlikely(!orig_node)) |
664 | goto out; |
665 | |
666 | /* update RTO with the new sampled RTT, if any */ |
667 | rtt = jiffies_to_msecs(j: jiffies) - ntohl(icmp->timestamp); |
668 | if (icmp->timestamp && rtt) |
669 | batadv_tp_update_rto(tp_vars, new_rtt: rtt); |
670 | |
671 | /* ACK for new data... reset the timer */ |
672 | batadv_tp_reset_sender_timer(tp_vars); |
673 | |
674 | recv_ack = ntohl(icmp->seqno); |
675 | |
676 | /* check if this ACK is a duplicate */ |
677 | if (atomic_read(v: &tp_vars->last_acked) == recv_ack) { |
678 | atomic_inc(v: &tp_vars->dup_acks); |
679 | if (atomic_read(v: &tp_vars->dup_acks) != 3) |
680 | goto out; |
681 | |
682 | if (recv_ack >= tp_vars->recover) |
683 | goto out; |
684 | |
685 | /* if this is the third duplicate ACK do Fast Retransmit */ |
686 | batadv_tp_send_msg(tp_vars, src: primary_if->net_dev->dev_addr, |
687 | orig_node, seqno: recv_ack, len: packet_len, |
688 | session: icmp->session, uid: icmp->uid, |
689 | timestamp: jiffies_to_msecs(j: jiffies)); |
690 | |
691 | spin_lock_bh(lock: &tp_vars->cwnd_lock); |
692 | |
693 | /* Fast Recovery */ |
694 | tp_vars->fast_recovery = true; |
695 | /* Set recover to the last outstanding seqno when Fast Recovery |
696 | * is entered. RFC6582, Section 3.2, step 1 |
697 | */ |
698 | tp_vars->recover = tp_vars->last_sent; |
699 | tp_vars->ss_threshold = tp_vars->cwnd >> 1; |
700 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
701 | "Meter: Fast Recovery, (cur cwnd=%u) ss_thr=%u last_sent=%u recv_ack=%u\n" , |
702 | tp_vars->cwnd, tp_vars->ss_threshold, |
703 | tp_vars->last_sent, recv_ack); |
704 | tp_vars->cwnd = batadv_tp_cwnd(base: tp_vars->ss_threshold, increment: 3 * mss, |
705 | min: mss); |
706 | tp_vars->dec_cwnd = 0; |
707 | tp_vars->last_sent = recv_ack; |
708 | |
709 | spin_unlock_bh(lock: &tp_vars->cwnd_lock); |
710 | } else { |
711 | /* count the acked data */ |
712 | atomic64_add(i: recv_ack - atomic_read(v: &tp_vars->last_acked), |
713 | v: &tp_vars->tot_sent); |
714 | /* reset the duplicate ACKs counter */ |
715 | atomic_set(v: &tp_vars->dup_acks, i: 0); |
716 | |
717 | if (tp_vars->fast_recovery) { |
718 | /* partial ACK */ |
719 | if (batadv_seq_before(recv_ack, tp_vars->recover)) { |
720 | /* this is another hole in the window. React |
721 | * immediately as specified by NewReno (see |
722 | * Section 3.2 of RFC6582 for details) |
723 | */ |
724 | dev_addr = primary_if->net_dev->dev_addr; |
725 | batadv_tp_send_msg(tp_vars, src: dev_addr, |
726 | orig_node, seqno: recv_ack, |
727 | len: packet_len, session: icmp->session, |
728 | uid: icmp->uid, |
729 | timestamp: jiffies_to_msecs(j: jiffies)); |
730 | tp_vars->cwnd = batadv_tp_cwnd(base: tp_vars->cwnd, |
731 | increment: mss, min: mss); |
732 | } else { |
733 | tp_vars->fast_recovery = false; |
734 | /* set cwnd to the value of ss_threshold at the |
735 | * moment that Fast Recovery was entered. |
736 | * RFC6582, Section 3.2, step 3 |
737 | */ |
738 | cwnd = batadv_tp_cwnd(base: tp_vars->ss_threshold, increment: 0, |
739 | min: mss); |
740 | tp_vars->cwnd = cwnd; |
741 | } |
742 | goto move_twnd; |
743 | } |
744 | |
745 | if (recv_ack - atomic_read(v: &tp_vars->last_acked) >= mss) |
746 | batadv_tp_update_cwnd(tp_vars, mss); |
747 | move_twnd: |
748 | /* move the Transmit Window */ |
749 | atomic_set(v: &tp_vars->last_acked, i: recv_ack); |
750 | } |
751 | |
752 | wake_up(&tp_vars->more_bytes); |
753 | out: |
754 | batadv_hardif_put(hard_iface: primary_if); |
755 | batadv_orig_node_put(orig_node); |
756 | batadv_tp_vars_put(tp_vars); |
757 | } |
758 | |
759 | /** |
760 | * batadv_tp_avail() - check if congestion window is not full |
761 | * @tp_vars: the private data of the current TP meter session |
762 | * @payload_len: size of the payload of a single message |
763 | * |
764 | * Return: true when congestion window is not full, false otherwise |
765 | */ |
766 | static bool batadv_tp_avail(struct batadv_tp_vars *tp_vars, |
767 | size_t payload_len) |
768 | { |
769 | u32 win_left, win_limit; |
770 | |
771 | win_limit = atomic_read(v: &tp_vars->last_acked) + tp_vars->cwnd; |
772 | win_left = win_limit - tp_vars->last_sent; |
773 | |
774 | return win_left >= payload_len; |
775 | } |
776 | |
777 | /** |
778 | * batadv_tp_wait_available() - wait until congestion window becomes free or |
779 | * timeout is reached |
780 | * @tp_vars: the private data of the current TP meter session |
781 | * @plen: size of the payload of a single message |
782 | * |
783 | * Return: 0 if the condition evaluated to false after the timeout elapsed, |
784 | * 1 if the condition evaluated to true after the timeout elapsed, the |
785 | * remaining jiffies (at least 1) if the condition evaluated to true before |
786 | * the timeout elapsed, or -ERESTARTSYS if it was interrupted by a signal. |
787 | */ |
788 | static int batadv_tp_wait_available(struct batadv_tp_vars *tp_vars, size_t plen) |
789 | { |
790 | int ret; |
791 | |
792 | ret = wait_event_interruptible_timeout(tp_vars->more_bytes, |
793 | batadv_tp_avail(tp_vars, plen), |
794 | HZ / 10); |
795 | |
796 | return ret; |
797 | } |
798 | |
799 | /** |
800 | * batadv_tp_send() - main sending thread of a tp meter session |
801 | * @arg: address of the related tp_vars |
802 | * |
803 | * Return: nothing, this function never returns |
804 | */ |
805 | static int batadv_tp_send(void *arg) |
806 | { |
807 | struct batadv_tp_vars *tp_vars = arg; |
808 | struct batadv_priv *bat_priv = tp_vars->bat_priv; |
809 | struct batadv_hard_iface *primary_if = NULL; |
810 | struct batadv_orig_node *orig_node = NULL; |
811 | size_t payload_len, packet_len; |
812 | int err = 0; |
813 | |
814 | if (unlikely(tp_vars->role != BATADV_TP_SENDER)) { |
815 | err = BATADV_TP_REASON_DST_UNREACHABLE; |
816 | tp_vars->reason = err; |
817 | goto out; |
818 | } |
819 | |
820 | orig_node = batadv_orig_hash_find(bat_priv, data: tp_vars->other_end); |
821 | if (unlikely(!orig_node)) { |
822 | err = BATADV_TP_REASON_DST_UNREACHABLE; |
823 | tp_vars->reason = err; |
824 | goto out; |
825 | } |
826 | |
827 | primary_if = batadv_primary_if_get_selected(bat_priv); |
828 | if (unlikely(!primary_if)) { |
829 | err = BATADV_TP_REASON_DST_UNREACHABLE; |
830 | tp_vars->reason = err; |
831 | goto out; |
832 | } |
833 | |
834 | /* assume that all the hard_interfaces have a correctly |
835 | * configured MTU, so use the soft_iface MTU as MSS. |
836 | * This might not be true and in that case the fragmentation |
837 | * should be used. |
838 | * Now, try to send the packet as it is |
839 | */ |
840 | payload_len = BATADV_TP_PLEN; |
841 | BUILD_BUG_ON(sizeof(struct batadv_icmp_tp_packet) > BATADV_TP_PLEN); |
842 | |
843 | batadv_tp_reset_sender_timer(tp_vars); |
844 | |
845 | /* queue the worker in charge of terminating the test */ |
846 | queue_delayed_work(wq: batadv_event_workqueue, dwork: &tp_vars->finish_work, |
847 | delay: msecs_to_jiffies(m: tp_vars->test_length)); |
848 | |
849 | while (atomic_read(v: &tp_vars->sending) != 0) { |
850 | if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) { |
851 | batadv_tp_wait_available(tp_vars, plen: payload_len); |
852 | continue; |
853 | } |
854 | |
855 | /* to emulate normal unicast traffic, add to the payload len |
856 | * the size of the unicast header |
857 | */ |
858 | packet_len = payload_len + sizeof(struct batadv_unicast_packet); |
859 | |
860 | err = batadv_tp_send_msg(tp_vars, src: primary_if->net_dev->dev_addr, |
861 | orig_node, seqno: tp_vars->last_sent, |
862 | len: packet_len, |
863 | session: tp_vars->session, uid: tp_vars->icmp_uid, |
864 | timestamp: jiffies_to_msecs(j: jiffies)); |
865 | |
866 | /* something went wrong during the preparation/transmission */ |
867 | if (unlikely(err && err != BATADV_TP_REASON_CANT_SEND)) { |
868 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
869 | "Meter: %s() cannot send packets (%d)\n" , |
870 | __func__, err); |
871 | /* ensure nobody else tries to stop the thread now */ |
872 | if (atomic_dec_and_test(v: &tp_vars->sending)) |
873 | tp_vars->reason = err; |
874 | break; |
875 | } |
876 | |
877 | /* right-shift the TWND */ |
878 | if (!err) |
879 | tp_vars->last_sent += payload_len; |
880 | |
881 | cond_resched(); |
882 | } |
883 | |
884 | out: |
885 | batadv_hardif_put(hard_iface: primary_if); |
886 | batadv_orig_node_put(orig_node); |
887 | |
888 | batadv_tp_sender_end(bat_priv, tp_vars); |
889 | batadv_tp_sender_cleanup(bat_priv, tp_vars); |
890 | |
891 | batadv_tp_vars_put(tp_vars); |
892 | |
893 | return 0; |
894 | } |
895 | |
896 | /** |
897 | * batadv_tp_start_kthread() - start new thread which manages the tp meter |
898 | * sender |
899 | * @tp_vars: the private data of the current TP meter session |
900 | */ |
901 | static void batadv_tp_start_kthread(struct batadv_tp_vars *tp_vars) |
902 | { |
903 | struct task_struct *kthread; |
904 | struct batadv_priv *bat_priv = tp_vars->bat_priv; |
905 | u32 session_cookie; |
906 | |
907 | kref_get(kref: &tp_vars->refcount); |
908 | kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter" ); |
909 | if (IS_ERR(ptr: kthread)) { |
910 | session_cookie = batadv_tp_session_cookie(session: tp_vars->session, |
911 | icmp_uid: tp_vars->icmp_uid); |
912 | pr_err("batadv: cannot create tp meter kthread\n" ); |
913 | batadv_tp_batctl_error_notify(reason: BATADV_TP_REASON_MEMORY_ERROR, |
914 | dst: tp_vars->other_end, |
915 | bat_priv, cookie: session_cookie); |
916 | |
917 | /* drop reserved reference for kthread */ |
918 | batadv_tp_vars_put(tp_vars); |
919 | |
920 | /* cleanup of failed tp meter variables */ |
921 | batadv_tp_sender_cleanup(bat_priv, tp_vars); |
922 | return; |
923 | } |
924 | |
925 | wake_up_process(tsk: kthread); |
926 | } |
927 | |
928 | /** |
929 | * batadv_tp_start() - start a new tp meter session |
930 | * @bat_priv: the bat priv with all the soft interface information |
931 | * @dst: the receiver MAC address |
932 | * @test_length: test length in milliseconds |
933 | * @cookie: session cookie |
934 | */ |
935 | void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst, |
936 | u32 test_length, u32 *cookie) |
937 | { |
938 | struct batadv_tp_vars *tp_vars; |
939 | u8 session_id[2]; |
940 | u8 icmp_uid; |
941 | u32 session_cookie; |
942 | |
943 | get_random_bytes(buf: session_id, len: sizeof(session_id)); |
944 | get_random_bytes(buf: &icmp_uid, len: 1); |
945 | session_cookie = batadv_tp_session_cookie(session: session_id, icmp_uid); |
946 | *cookie = session_cookie; |
947 | |
948 | /* look for an already existing test towards this node */ |
949 | spin_lock_bh(lock: &bat_priv->tp_list_lock); |
950 | tp_vars = batadv_tp_list_find(bat_priv, dst); |
951 | if (tp_vars) { |
952 | spin_unlock_bh(lock: &bat_priv->tp_list_lock); |
953 | batadv_tp_vars_put(tp_vars); |
954 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
955 | "Meter: test to or from the same node already ongoing, aborting\n" ); |
956 | batadv_tp_batctl_error_notify(reason: BATADV_TP_REASON_ALREADY_ONGOING, |
957 | dst, bat_priv, cookie: session_cookie); |
958 | return; |
959 | } |
960 | |
961 | if (!atomic_add_unless(v: &bat_priv->tp_num, a: 1, BATADV_TP_MAX_NUM)) { |
962 | spin_unlock_bh(lock: &bat_priv->tp_list_lock); |
963 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
964 | "Meter: too many ongoing sessions, aborting (SEND)\n" ); |
965 | batadv_tp_batctl_error_notify(reason: BATADV_TP_REASON_TOO_MANY, dst, |
966 | bat_priv, cookie: session_cookie); |
967 | return; |
968 | } |
969 | |
970 | tp_vars = kmalloc(size: sizeof(*tp_vars), GFP_ATOMIC); |
971 | if (!tp_vars) { |
972 | spin_unlock_bh(lock: &bat_priv->tp_list_lock); |
973 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
974 | "Meter: %s cannot allocate list elements\n" , |
975 | __func__); |
976 | batadv_tp_batctl_error_notify(reason: BATADV_TP_REASON_MEMORY_ERROR, |
977 | dst, bat_priv, cookie: session_cookie); |
978 | return; |
979 | } |
980 | |
981 | /* initialize tp_vars */ |
982 | ether_addr_copy(dst: tp_vars->other_end, src: dst); |
983 | kref_init(kref: &tp_vars->refcount); |
984 | tp_vars->role = BATADV_TP_SENDER; |
985 | atomic_set(v: &tp_vars->sending, i: 1); |
986 | memcpy(tp_vars->session, session_id, sizeof(session_id)); |
987 | tp_vars->icmp_uid = icmp_uid; |
988 | |
989 | tp_vars->last_sent = BATADV_TP_FIRST_SEQ; |
990 | atomic_set(v: &tp_vars->last_acked, BATADV_TP_FIRST_SEQ); |
991 | tp_vars->fast_recovery = false; |
992 | tp_vars->recover = BATADV_TP_FIRST_SEQ; |
993 | |
994 | /* initialise the CWND to 3*MSS (Section 3.1 in RFC5681). |
995 | * For batman-adv the MSS is the size of the payload received by the |
996 | * soft_interface, hence its MTU |
997 | */ |
998 | tp_vars->cwnd = BATADV_TP_PLEN * 3; |
999 | /* at the beginning initialise the SS threshold to the biggest possible |
1000 | * window size, hence the AWND size |
1001 | */ |
1002 | tp_vars->ss_threshold = BATADV_TP_AWND; |
1003 | |
1004 | /* RTO initial value is 3 seconds. |
1005 | * Details in Section 2.1 of RFC6298 |
1006 | */ |
1007 | tp_vars->rto = 1000; |
1008 | tp_vars->srtt = 0; |
1009 | tp_vars->rttvar = 0; |
1010 | |
1011 | atomic64_set(v: &tp_vars->tot_sent, i: 0); |
1012 | |
1013 | kref_get(kref: &tp_vars->refcount); |
1014 | timer_setup(&tp_vars->timer, batadv_tp_sender_timeout, 0); |
1015 | |
1016 | tp_vars->bat_priv = bat_priv; |
1017 | tp_vars->start_time = jiffies; |
1018 | |
1019 | init_waitqueue_head(&tp_vars->more_bytes); |
1020 | |
1021 | spin_lock_init(&tp_vars->unacked_lock); |
1022 | INIT_LIST_HEAD(list: &tp_vars->unacked_list); |
1023 | |
1024 | spin_lock_init(&tp_vars->cwnd_lock); |
1025 | |
1026 | tp_vars->prerandom_offset = 0; |
1027 | spin_lock_init(&tp_vars->prerandom_lock); |
1028 | |
1029 | kref_get(kref: &tp_vars->refcount); |
1030 | hlist_add_head_rcu(n: &tp_vars->list, h: &bat_priv->tp_list); |
1031 | spin_unlock_bh(lock: &bat_priv->tp_list_lock); |
1032 | |
1033 | tp_vars->test_length = test_length; |
1034 | if (!tp_vars->test_length) |
1035 | tp_vars->test_length = BATADV_TP_DEF_TEST_LENGTH; |
1036 | |
1037 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1038 | "Meter: starting throughput meter towards %pM (length=%ums)\n" , |
1039 | dst, test_length); |
1040 | |
1041 | /* init work item for finished tp tests */ |
1042 | INIT_DELAYED_WORK(&tp_vars->finish_work, batadv_tp_sender_finish); |
1043 | |
1044 | /* start tp kthread. This way the write() call issued from userspace can |
1045 | * happily return and avoid to block |
1046 | */ |
1047 | batadv_tp_start_kthread(tp_vars); |
1048 | |
1049 | /* don't return reference to new tp_vars */ |
1050 | batadv_tp_vars_put(tp_vars); |
1051 | } |
1052 | |
1053 | /** |
1054 | * batadv_tp_stop() - stop currently running tp meter session |
1055 | * @bat_priv: the bat priv with all the soft interface information |
1056 | * @dst: the receiver MAC address |
1057 | * @return_value: reason for tp meter session stop |
1058 | */ |
1059 | void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst, |
1060 | u8 return_value) |
1061 | { |
1062 | struct batadv_orig_node *orig_node; |
1063 | struct batadv_tp_vars *tp_vars; |
1064 | |
1065 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1066 | "Meter: stopping test towards %pM\n" , dst); |
1067 | |
1068 | orig_node = batadv_orig_hash_find(bat_priv, data: dst); |
1069 | if (!orig_node) |
1070 | return; |
1071 | |
1072 | tp_vars = batadv_tp_list_find(bat_priv, dst: orig_node->orig); |
1073 | if (!tp_vars) { |
1074 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1075 | "Meter: trying to interrupt an already over connection\n" ); |
1076 | goto out; |
1077 | } |
1078 | |
1079 | batadv_tp_sender_shutdown(tp_vars, reason: return_value); |
1080 | batadv_tp_vars_put(tp_vars); |
1081 | out: |
1082 | batadv_orig_node_put(orig_node); |
1083 | } |
1084 | |
1085 | /** |
1086 | * batadv_tp_reset_receiver_timer() - reset the receiver shutdown timer |
1087 | * @tp_vars: the private data of the current TP meter session |
1088 | * |
1089 | * start the receiver shutdown timer or reset it if already started |
1090 | */ |
1091 | static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars) |
1092 | { |
1093 | mod_timer(timer: &tp_vars->timer, |
1094 | expires: jiffies + msecs_to_jiffies(BATADV_TP_RECV_TIMEOUT)); |
1095 | } |
1096 | |
1097 | /** |
1098 | * batadv_tp_receiver_shutdown() - stop a tp meter receiver when timeout is |
1099 | * reached without received ack |
1100 | * @t: address to timer_list inside tp_vars |
1101 | */ |
1102 | static void batadv_tp_receiver_shutdown(struct timer_list *t) |
1103 | { |
1104 | struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer); |
1105 | struct batadv_tp_unacked *un, *safe; |
1106 | struct batadv_priv *bat_priv; |
1107 | |
1108 | bat_priv = tp_vars->bat_priv; |
1109 | |
1110 | /* if there is recent activity rearm the timer */ |
1111 | if (!batadv_has_timed_out(timestamp: tp_vars->last_recv_time, |
1112 | BATADV_TP_RECV_TIMEOUT)) { |
1113 | /* reset the receiver shutdown timer */ |
1114 | batadv_tp_reset_receiver_timer(tp_vars); |
1115 | return; |
1116 | } |
1117 | |
1118 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1119 | "Shutting down for inactivity (more than %dms) from %pM\n" , |
1120 | BATADV_TP_RECV_TIMEOUT, tp_vars->other_end); |
1121 | |
1122 | spin_lock_bh(lock: &tp_vars->bat_priv->tp_list_lock); |
1123 | hlist_del_rcu(n: &tp_vars->list); |
1124 | spin_unlock_bh(lock: &tp_vars->bat_priv->tp_list_lock); |
1125 | |
1126 | /* drop list reference */ |
1127 | batadv_tp_vars_put(tp_vars); |
1128 | |
1129 | atomic_dec(v: &bat_priv->tp_num); |
1130 | |
1131 | spin_lock_bh(lock: &tp_vars->unacked_lock); |
1132 | list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { |
1133 | list_del(entry: &un->list); |
1134 | kfree(objp: un); |
1135 | } |
1136 | spin_unlock_bh(lock: &tp_vars->unacked_lock); |
1137 | |
1138 | /* drop reference of timer */ |
1139 | batadv_tp_vars_put(tp_vars); |
1140 | } |
1141 | |
1142 | /** |
1143 | * batadv_tp_send_ack() - send an ACK packet |
1144 | * @bat_priv: the bat priv with all the soft interface information |
1145 | * @dst: the mac address of the destination originator |
1146 | * @seq: the sequence number to ACK |
1147 | * @timestamp: the timestamp to echo back in the ACK |
1148 | * @session: session identifier |
1149 | * @socket_index: local ICMP socket identifier |
1150 | * |
1151 | * Return: 0 on success, a positive integer representing the reason of the |
1152 | * failure otherwise |
1153 | */ |
1154 | static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst, |
1155 | u32 seq, __be32 timestamp, const u8 *session, |
1156 | int socket_index) |
1157 | { |
1158 | struct batadv_hard_iface *primary_if = NULL; |
1159 | struct batadv_orig_node *orig_node; |
1160 | struct batadv_icmp_tp_packet *icmp; |
1161 | struct sk_buff *skb; |
1162 | int r, ret; |
1163 | |
1164 | orig_node = batadv_orig_hash_find(bat_priv, data: dst); |
1165 | if (unlikely(!orig_node)) { |
1166 | ret = BATADV_TP_REASON_DST_UNREACHABLE; |
1167 | goto out; |
1168 | } |
1169 | |
1170 | primary_if = batadv_primary_if_get_selected(bat_priv); |
1171 | if (unlikely(!primary_if)) { |
1172 | ret = BATADV_TP_REASON_DST_UNREACHABLE; |
1173 | goto out; |
1174 | } |
1175 | |
1176 | skb = netdev_alloc_skb_ip_align(NULL, length: sizeof(*icmp) + ETH_HLEN); |
1177 | if (unlikely(!skb)) { |
1178 | ret = BATADV_TP_REASON_MEMORY_ERROR; |
1179 | goto out; |
1180 | } |
1181 | |
1182 | skb_reserve(skb, ETH_HLEN); |
1183 | icmp = skb_put(skb, len: sizeof(*icmp)); |
1184 | icmp->packet_type = BATADV_ICMP; |
1185 | icmp->version = BATADV_COMPAT_VERSION; |
1186 | icmp->ttl = BATADV_TTL; |
1187 | icmp->msg_type = BATADV_TP; |
1188 | ether_addr_copy(dst: icmp->dst, src: orig_node->orig); |
1189 | ether_addr_copy(dst: icmp->orig, src: primary_if->net_dev->dev_addr); |
1190 | icmp->uid = socket_index; |
1191 | |
1192 | icmp->subtype = BATADV_TP_ACK; |
1193 | memcpy(icmp->session, session, sizeof(icmp->session)); |
1194 | icmp->seqno = htonl(seq); |
1195 | icmp->timestamp = timestamp; |
1196 | |
1197 | /* send the ack */ |
1198 | r = batadv_send_skb_to_orig(skb, orig_node, NULL); |
1199 | if (unlikely(r < 0) || r == NET_XMIT_DROP) { |
1200 | ret = BATADV_TP_REASON_DST_UNREACHABLE; |
1201 | goto out; |
1202 | } |
1203 | ret = 0; |
1204 | |
1205 | out: |
1206 | batadv_orig_node_put(orig_node); |
1207 | batadv_hardif_put(hard_iface: primary_if); |
1208 | |
1209 | return ret; |
1210 | } |
1211 | |
1212 | /** |
1213 | * batadv_tp_handle_out_of_order() - store an out of order packet |
1214 | * @tp_vars: the private data of the current TP meter session |
1215 | * @skb: the buffer containing the received packet |
1216 | * |
1217 | * Store the out of order packet in the unacked list for late processing. This |
1218 | * packets are kept in this list so that they can be ACKed at once as soon as |
1219 | * all the previous packets have been received |
1220 | * |
1221 | * Return: true if the packed has been successfully processed, false otherwise |
1222 | */ |
1223 | static bool batadv_tp_handle_out_of_order(struct batadv_tp_vars *tp_vars, |
1224 | const struct sk_buff *skb) |
1225 | { |
1226 | const struct batadv_icmp_tp_packet *icmp; |
1227 | struct batadv_tp_unacked *un, *new; |
1228 | u32 payload_len; |
1229 | bool added = false; |
1230 | |
1231 | new = kmalloc(size: sizeof(*new), GFP_ATOMIC); |
1232 | if (unlikely(!new)) |
1233 | return false; |
1234 | |
1235 | icmp = (struct batadv_icmp_tp_packet *)skb->data; |
1236 | |
1237 | new->seqno = ntohl(icmp->seqno); |
1238 | payload_len = skb->len - sizeof(struct batadv_unicast_packet); |
1239 | new->len = payload_len; |
1240 | |
1241 | spin_lock_bh(lock: &tp_vars->unacked_lock); |
1242 | /* if the list is empty immediately attach this new object */ |
1243 | if (list_empty(head: &tp_vars->unacked_list)) { |
1244 | list_add(new: &new->list, head: &tp_vars->unacked_list); |
1245 | goto out; |
1246 | } |
1247 | |
1248 | /* otherwise loop over the list and either drop the packet because this |
1249 | * is a duplicate or store it at the right position. |
1250 | * |
1251 | * The iteration is done in the reverse way because it is likely that |
1252 | * the last received packet (the one being processed now) has a bigger |
1253 | * seqno than all the others already stored. |
1254 | */ |
1255 | list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) { |
1256 | /* check for duplicates */ |
1257 | if (new->seqno == un->seqno) { |
1258 | if (new->len > un->len) |
1259 | un->len = new->len; |
1260 | kfree(objp: new); |
1261 | added = true; |
1262 | break; |
1263 | } |
1264 | |
1265 | /* look for the right position */ |
1266 | if (batadv_seq_before(new->seqno, un->seqno)) |
1267 | continue; |
1268 | |
1269 | /* as soon as an entry having a bigger seqno is found, the new |
1270 | * one is attached _after_ it. In this way the list is kept in |
1271 | * ascending order |
1272 | */ |
1273 | list_add_tail(new: &new->list, head: &un->list); |
1274 | added = true; |
1275 | break; |
1276 | } |
1277 | |
1278 | /* received packet with smallest seqno out of order; add it to front */ |
1279 | if (!added) |
1280 | list_add(new: &new->list, head: &tp_vars->unacked_list); |
1281 | |
1282 | out: |
1283 | spin_unlock_bh(lock: &tp_vars->unacked_lock); |
1284 | |
1285 | return true; |
1286 | } |
1287 | |
1288 | /** |
1289 | * batadv_tp_ack_unordered() - update number received bytes in current stream |
1290 | * without gaps |
1291 | * @tp_vars: the private data of the current TP meter session |
1292 | */ |
1293 | static void batadv_tp_ack_unordered(struct batadv_tp_vars *tp_vars) |
1294 | { |
1295 | struct batadv_tp_unacked *un, *safe; |
1296 | u32 to_ack; |
1297 | |
1298 | /* go through the unacked packet list and possibly ACK them as |
1299 | * well |
1300 | */ |
1301 | spin_lock_bh(lock: &tp_vars->unacked_lock); |
1302 | list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) { |
1303 | /* the list is ordered, therefore it is possible to stop as soon |
1304 | * there is a gap between the last acked seqno and the seqno of |
1305 | * the packet under inspection |
1306 | */ |
1307 | if (batadv_seq_before(tp_vars->last_recv, un->seqno)) |
1308 | break; |
1309 | |
1310 | to_ack = un->seqno + un->len - tp_vars->last_recv; |
1311 | |
1312 | if (batadv_seq_before(tp_vars->last_recv, un->seqno + un->len)) |
1313 | tp_vars->last_recv += to_ack; |
1314 | |
1315 | list_del(entry: &un->list); |
1316 | kfree(objp: un); |
1317 | } |
1318 | spin_unlock_bh(lock: &tp_vars->unacked_lock); |
1319 | } |
1320 | |
1321 | /** |
1322 | * batadv_tp_init_recv() - return matching or create new receiver tp_vars |
1323 | * @bat_priv: the bat priv with all the soft interface information |
1324 | * @icmp: received icmp tp msg |
1325 | * |
1326 | * Return: corresponding tp_vars or NULL on errors |
1327 | */ |
1328 | static struct batadv_tp_vars * |
1329 | batadv_tp_init_recv(struct batadv_priv *bat_priv, |
1330 | const struct batadv_icmp_tp_packet *icmp) |
1331 | { |
1332 | struct batadv_tp_vars *tp_vars; |
1333 | |
1334 | spin_lock_bh(lock: &bat_priv->tp_list_lock); |
1335 | tp_vars = batadv_tp_list_find_session(bat_priv, dst: icmp->orig, |
1336 | session: icmp->session); |
1337 | if (tp_vars) |
1338 | goto out_unlock; |
1339 | |
1340 | if (!atomic_add_unless(v: &bat_priv->tp_num, a: 1, BATADV_TP_MAX_NUM)) { |
1341 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1342 | "Meter: too many ongoing sessions, aborting (RECV)\n" ); |
1343 | goto out_unlock; |
1344 | } |
1345 | |
1346 | tp_vars = kmalloc(size: sizeof(*tp_vars), GFP_ATOMIC); |
1347 | if (!tp_vars) |
1348 | goto out_unlock; |
1349 | |
1350 | ether_addr_copy(dst: tp_vars->other_end, src: icmp->orig); |
1351 | tp_vars->role = BATADV_TP_RECEIVER; |
1352 | memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session)); |
1353 | tp_vars->last_recv = BATADV_TP_FIRST_SEQ; |
1354 | tp_vars->bat_priv = bat_priv; |
1355 | kref_init(kref: &tp_vars->refcount); |
1356 | |
1357 | spin_lock_init(&tp_vars->unacked_lock); |
1358 | INIT_LIST_HEAD(list: &tp_vars->unacked_list); |
1359 | |
1360 | kref_get(kref: &tp_vars->refcount); |
1361 | hlist_add_head_rcu(n: &tp_vars->list, h: &bat_priv->tp_list); |
1362 | |
1363 | kref_get(kref: &tp_vars->refcount); |
1364 | timer_setup(&tp_vars->timer, batadv_tp_receiver_shutdown, 0); |
1365 | |
1366 | batadv_tp_reset_receiver_timer(tp_vars); |
1367 | |
1368 | out_unlock: |
1369 | spin_unlock_bh(lock: &bat_priv->tp_list_lock); |
1370 | |
1371 | return tp_vars; |
1372 | } |
1373 | |
1374 | /** |
1375 | * batadv_tp_recv_msg() - process a single data message |
1376 | * @bat_priv: the bat priv with all the soft interface information |
1377 | * @skb: the buffer containing the received packet |
1378 | * |
1379 | * Process a received TP MSG packet |
1380 | */ |
1381 | static void batadv_tp_recv_msg(struct batadv_priv *bat_priv, |
1382 | const struct sk_buff *skb) |
1383 | { |
1384 | const struct batadv_icmp_tp_packet *icmp; |
1385 | struct batadv_tp_vars *tp_vars; |
1386 | size_t packet_size; |
1387 | u32 seqno; |
1388 | |
1389 | icmp = (struct batadv_icmp_tp_packet *)skb->data; |
1390 | |
1391 | seqno = ntohl(icmp->seqno); |
1392 | /* check if this is the first seqno. This means that if the |
1393 | * first packet is lost, the tp meter does not work anymore! |
1394 | */ |
1395 | if (seqno == BATADV_TP_FIRST_SEQ) { |
1396 | tp_vars = batadv_tp_init_recv(bat_priv, icmp); |
1397 | if (!tp_vars) { |
1398 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1399 | "Meter: seqno != BATADV_TP_FIRST_SEQ cannot initiate connection\n" ); |
1400 | goto out; |
1401 | } |
1402 | } else { |
1403 | tp_vars = batadv_tp_list_find_session(bat_priv, dst: icmp->orig, |
1404 | session: icmp->session); |
1405 | if (!tp_vars) { |
1406 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1407 | "Unexpected packet from %pM!\n" , |
1408 | icmp->orig); |
1409 | goto out; |
1410 | } |
1411 | } |
1412 | |
1413 | if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) { |
1414 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1415 | "Meter: dropping packet: not expected (role=%u)\n" , |
1416 | tp_vars->role); |
1417 | goto out; |
1418 | } |
1419 | |
1420 | tp_vars->last_recv_time = jiffies; |
1421 | |
1422 | /* if the packet is a duplicate, it may be the case that an ACK has been |
1423 | * lost. Resend the ACK |
1424 | */ |
1425 | if (batadv_seq_before(seqno, tp_vars->last_recv)) |
1426 | goto send_ack; |
1427 | |
1428 | /* if the packet is out of order enqueue it */ |
1429 | if (ntohl(icmp->seqno) != tp_vars->last_recv) { |
1430 | /* exit immediately (and do not send any ACK) if the packet has |
1431 | * not been enqueued correctly |
1432 | */ |
1433 | if (!batadv_tp_handle_out_of_order(tp_vars, skb)) |
1434 | goto out; |
1435 | |
1436 | /* send a duplicate ACK */ |
1437 | goto send_ack; |
1438 | } |
1439 | |
1440 | /* if everything was fine count the ACKed bytes */ |
1441 | packet_size = skb->len - sizeof(struct batadv_unicast_packet); |
1442 | tp_vars->last_recv += packet_size; |
1443 | |
1444 | /* check if this ordered message filled a gap.... */ |
1445 | batadv_tp_ack_unordered(tp_vars); |
1446 | |
1447 | send_ack: |
1448 | /* send the ACK. If the received packet was out of order, the ACK that |
1449 | * is going to be sent is a duplicate (the sender will count them and |
1450 | * possibly enter Fast Retransmit as soon as it has reached 3) |
1451 | */ |
1452 | batadv_tp_send_ack(bat_priv, dst: icmp->orig, seq: tp_vars->last_recv, |
1453 | timestamp: icmp->timestamp, session: icmp->session, socket_index: icmp->uid); |
1454 | out: |
1455 | batadv_tp_vars_put(tp_vars); |
1456 | } |
1457 | |
1458 | /** |
1459 | * batadv_tp_meter_recv() - main TP Meter receiving function |
1460 | * @bat_priv: the bat priv with all the soft interface information |
1461 | * @skb: the buffer containing the received packet |
1462 | */ |
1463 | void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb) |
1464 | { |
1465 | struct batadv_icmp_tp_packet *icmp; |
1466 | |
1467 | icmp = (struct batadv_icmp_tp_packet *)skb->data; |
1468 | |
1469 | switch (icmp->subtype) { |
1470 | case BATADV_TP_MSG: |
1471 | batadv_tp_recv_msg(bat_priv, skb); |
1472 | break; |
1473 | case BATADV_TP_ACK: |
1474 | batadv_tp_recv_ack(bat_priv, skb); |
1475 | break; |
1476 | default: |
1477 | batadv_dbg(BATADV_DBG_TP_METER, bat_priv, |
1478 | "Received unknown TP Metric packet type %u\n" , |
1479 | icmp->subtype); |
1480 | } |
1481 | consume_skb(skb); |
1482 | } |
1483 | |
1484 | /** |
1485 | * batadv_tp_meter_init() - initialize global tp_meter structures |
1486 | */ |
1487 | void __init batadv_tp_meter_init(void) |
1488 | { |
1489 | get_random_bytes(buf: batadv_tp_prerandom, len: sizeof(batadv_tp_prerandom)); |
1490 | } |
1491 | |