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(&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(tp_vars->cwnd, mss, mss);
151 spin_unlock_bh(&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(&tp_vars->cwnd_lock);
160 return;
161 }
162
163 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss);
164 tp_vars->dec_cwnd = 0;
165
166 spin_unlock_bh(&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(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, 0, 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(pos->other_end, 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(pos->other_end, dst))
309 continue;
310
311 if (memcmp(pos->session, session, 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(&tp_vars->unacked_lock);
345 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
346 list_del(&un->list);
347 kfree(un);
348 }
349 spin_unlock_bh(&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(&tp_vars->refcount, 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(&tp_vars->finish_work);
376
377 spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
378 hlist_del_rcu(&tp_vars->list);
379 spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
380
381 /* drop list reference */
382 batadv_tp_vars_put(tp_vars);
383
384 atomic_dec(&tp_vars->bat_priv->tp_num);
385
386 /* kill the timer and remove its reference */
387 del_timer_sync(&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(&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(tp_vars->session,
420 tp_vars->icmp_uid);
421
422 batadv_tp_batctl_notify(tp_vars->reason,
423 tp_vars->other_end,
424 bat_priv,
425 tp_vars->start_time,
426 atomic64_read(&tp_vars->tot_sent),
427 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(&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, 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(&tp_vars->timer, jiffies + msecs_to_jiffies(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(&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 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(&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(&tp_vars->cwnd_lock);
520
521 /* resend the non-ACKed packets.. */
522 tp_vars->last_sent = atomic_read(&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(&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(&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, 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, sizeof(*icmp));
594
595 /* fill the icmp header */
596 ether_addr_copy(icmp->dst, orig_node->orig);
597 ether_addr_copy(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, data_len);
611 batadv_tp_fill_prerandom(tp_vars, data, 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, icmp->orig,
646 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, 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(jiffies) - ntohl(icmp->timestamp);
668 if (icmp->timestamp && rtt)
669 batadv_tp_update_rto(tp_vars, 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(&tp_vars->last_acked) == recv_ack) {
678 atomic_inc(&tp_vars->dup_acks);
679 if (atomic_read(&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, primary_if->net_dev->dev_addr,
687 orig_node, recv_ack, packet_len,
688 icmp->session, icmp->uid,
689 jiffies_to_msecs(jiffies));
690
691 spin_lock_bh(&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(tp_vars->ss_threshold, 3 * mss,
705 mss);
706 tp_vars->dec_cwnd = 0;
707 tp_vars->last_sent = recv_ack;
708
709 spin_unlock_bh(&tp_vars->cwnd_lock);
710 } else {
711 /* count the acked data */
712 atomic64_add(recv_ack - atomic_read(&tp_vars->last_acked),
713 &tp_vars->tot_sent);
714 /* reset the duplicate ACKs counter */
715 atomic_set(&tp_vars->dup_acks, 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, dev_addr,
726 orig_node, recv_ack,
727 packet_len, icmp->session,
728 icmp->uid,
729 jiffies_to_msecs(jiffies));
730 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd,
731 mss, 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(tp_vars->ss_threshold, 0,
739 mss);
740 tp_vars->cwnd = cwnd;
741 }
742 goto move_twnd;
743 }
744
745 if (recv_ack - atomic_read(&tp_vars->last_acked) >= mss)
746 batadv_tp_update_cwnd(tp_vars, mss);
747 move_twnd:
748 /* move the Transmit Window */
749 atomic_set(&tp_vars->last_acked, recv_ack);
750 }
751
752 wake_up(&tp_vars->more_bytes);
753 out:
754 batadv_hardif_put(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(&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, 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(batadv_event_workqueue, &tp_vars->finish_work,
847 msecs_to_jiffies(tp_vars->test_length));
848
849 while (atomic_read(&tp_vars->sending) != 0) {
850 if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) {
851 batadv_tp_wait_available(tp_vars, 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, primary_if->net_dev->dev_addr,
861 orig_node, tp_vars->last_sent,
862 packet_len,
863 tp_vars->session, tp_vars->icmp_uid,
864 jiffies_to_msecs(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(&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(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(&tp_vars->refcount);
908 kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter");
909 if (IS_ERR(kthread)) {
910 session_cookie = batadv_tp_session_cookie(tp_vars->session,
911 tp_vars->icmp_uid);
912 pr_err("batadv: cannot create tp meter kthread\n");
913 batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
914 tp_vars->other_end,
915 bat_priv, 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(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(session_id, sizeof(session_id));
944 get_random_bytes(&icmp_uid, 1);
945 session_cookie = batadv_tp_session_cookie(session_id, icmp_uid);
946 *cookie = session_cookie;
947
948 /* look for an already existing test towards this node */
949 spin_lock_bh(&bat_priv->tp_list_lock);
950 tp_vars = batadv_tp_list_find(bat_priv, dst);
951 if (tp_vars) {
952 spin_unlock_bh(&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(BATADV_TP_REASON_ALREADY_ONGOING,
957 dst, bat_priv, session_cookie);
958 return;
959 }
960
961 if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
962 spin_unlock_bh(&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(BATADV_TP_REASON_TOO_MANY, dst,
966 bat_priv, session_cookie);
967 return;
968 }
969
970 tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
971 if (!tp_vars) {
972 spin_unlock_bh(&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(BATADV_TP_REASON_MEMORY_ERROR,
977 dst, bat_priv, session_cookie);
978 return;
979 }
980
981 /* initialize tp_vars */
982 ether_addr_copy(tp_vars->other_end, dst);
983 kref_init(&tp_vars->refcount);
984 tp_vars->role = BATADV_TP_SENDER;
985 atomic_set(&tp_vars->sending, 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(&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(&tp_vars->tot_sent, 0);
1012
1013 kref_get(&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(&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(&tp_vars->refcount);
1030 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1031 spin_unlock_bh(&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, dst);
1069 if (!orig_node)
1070 return;
1071
1072 tp_vars = batadv_tp_list_find(bat_priv, 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, 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(&tp_vars->timer,
1094 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(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(&tp_vars->bat_priv->tp_list_lock);
1123 hlist_del_rcu(&tp_vars->list);
1124 spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
1125
1126 /* drop list reference */
1127 batadv_tp_vars_put(tp_vars);
1128
1129 atomic_dec(&bat_priv->tp_num);
1130
1131 spin_lock_bh(&tp_vars->unacked_lock);
1132 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
1133 list_del(&un->list);
1134 kfree(un);
1135 }
1136 spin_unlock_bh(&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, 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, 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, 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(icmp->dst, orig_node->orig);
1189 ether_addr_copy(icmp->orig, 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(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(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(&tp_vars->unacked_lock);
1242 /* if the list is empty immediately attach this new object */
1243 if (list_empty(&tp_vars->unacked_list)) {
1244 list_add(&new->list, &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(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->list, &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->list, &tp_vars->unacked_list);
1281
1282 out:
1283 spin_unlock_bh(&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(&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(&un->list);
1316 kfree(un);
1317 }
1318 spin_unlock_bh(&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(&bat_priv->tp_list_lock);
1335 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
1336 icmp->session);
1337 if (tp_vars)
1338 goto out_unlock;
1339
1340 if (!atomic_add_unless(&bat_priv->tp_num, 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(sizeof(*tp_vars), GFP_ATOMIC);
1347 if (!tp_vars)
1348 goto out_unlock;
1349
1350 ether_addr_copy(tp_vars->other_end, 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(&tp_vars->refcount);
1356
1357 spin_lock_init(&tp_vars->unacked_lock);
1358 INIT_LIST_HEAD(&tp_vars->unacked_list);
1359
1360 kref_get(&tp_vars->refcount);
1361 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1362
1363 kref_get(&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(&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, icmp->orig,
1404 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, icmp->orig, tp_vars->last_recv,
1453 icmp->timestamp, icmp->session, 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(batadv_tp_prerandom, sizeof(batadv_tp_prerandom));
1490 }
1491
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