1 /* Copyright (C) 2012-2016 B.A.T.M.A.N. contributors:
2 *
3 * Edo Monticelli, Antonio Quartulli
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18 #include "tp_meter.h"
19 #include "main.h"
20
21 #include <linux/atomic.h>
22 #include <linux/bug.h>
23 #include <linux/byteorder/generic.h>
24 #include <linux/cache.h>
25 #include <linux/compiler.h>
26 #include <linux/device.h>
27 #include <linux/etherdevice.h>
28 #include <linux/fs.h>
29 #include <linux/if_ether.h>
30 #include <linux/jiffies.h>
31 #include <linux/kernel.h>
32 #include <linux/kref.h>
33 #include <linux/kthread.h>
34 #include <linux/list.h>
35 #include <linux/netdevice.h>
36 #include <linux/param.h>
37 #include <linux/printk.h>
38 #include <linux/random.h>
39 #include <linux/rculist.h>
40 #include <linux/rcupdate.h>
41 #include <linux/sched.h>
42 #include <linux/skbuff.h>
43 #include <linux/slab.h>
44 #include <linux/spinlock.h>
45 #include <linux/stddef.h>
46 #include <linux/string.h>
47 #include <linux/timer.h>
48 #include <linux/wait.h>
49 #include <linux/workqueue.h>
50 #include <uapi/linux/batman_adv.h>
51
52 #include "hard-interface.h"
53 #include "log.h"
54 #include "netlink.h"
55 #include "originator.h"
56 #include "packet.h"
57 #include "send.h"
58
59 /**
60 * BATADV_TP_DEF_TEST_LENGTH - Default test length if not specified by the user
61 * in milliseconds
62 */
63 #define BATADV_TP_DEF_TEST_LENGTH 10000
64
65 /**
66 * BATADV_TP_AWND - Advertised window by the receiver (in bytes)
67 */
68 #define BATADV_TP_AWND 0x20000000
69
70 /**
71 * BATADV_TP_RECV_TIMEOUT - Receiver activity timeout. If the receiver does not
72 * get anything for such amount of milliseconds, the connection is killed
73 */
74 #define BATADV_TP_RECV_TIMEOUT 1000
75
76 /**
77 * BATADV_TP_MAX_RTO - Maximum sender timeout. If the sender RTO gets beyond
78 * such amound of milliseconds, the receiver is considered unreachable and the
79 * connection is killed
80 */
81 #define BATADV_TP_MAX_RTO 30000
82
83 /**
84 * BATADV_TP_FIRST_SEQ - First seqno of each session. The number is rather high
85 * in order to immediately trigger a wrap around (test purposes)
86 */
87 #define BATADV_TP_FIRST_SEQ ((u32)-1 - 2000)
88
89 /**
90 * BATADV_TP_PLEN - length of the payload (data after the batadv_unicast header)
91 * to simulate
92 */
93 #define BATADV_TP_PLEN (BATADV_TP_PACKET_LEN - ETH_HLEN - \
94 sizeof(struct batadv_unicast_packet))
95
96 static u8 batadv_tp_prerandom[4096] __read_mostly;
97
98 /**
99 * batadv_tp_session_cookie - generate session cookie based on session ids
100 * @session: TP session identifier
101 * @icmp_uid: icmp pseudo uid of the tp session
102 *
103 * Return: 32 bit tp_meter session cookie
104 */
105 static u32 batadv_tp_session_cookie(const u8 session[2], u8 icmp_uid)
106 {
107 u32 cookie;
108
109 cookie = icmp_uid << 16;
110 cookie |= session[0] << 8;
111 cookie |= session[1];
112
113 return cookie;
114 }
115
116 /**
117 * batadv_tp_cwnd - compute the new cwnd size
118 * @base: base cwnd size value
119 * @increment: the value to add to base to get the new size
120 * @min: minumim cwnd value (usually MSS)
121 *
122 * Return the new cwnd size and ensures it does not exceed the Advertised
123 * Receiver Window size. It is wrap around safe.
124 * For details refer to Section 3.1 of RFC5681
125 *
126 * Return: new congestion window size in bytes
127 */
128 static u32 batadv_tp_cwnd(u32 base, u32 increment, u32 min)
129 {
130 u32 new_size = base + increment;
131
132 /* check for wrap-around */
133 if (new_size < base)
134 new_size = (u32)ULONG_MAX;
135
136 new_size = min_t(u32, new_size, BATADV_TP_AWND);
137
138 return max_t(u32, new_size, min);
139 }
140
141 /**
142 * batadv_tp_updated_cwnd - update the Congestion Windows
143 * @tp_vars: the private data of the current TP meter session
144 * @mss: maximum segment size of transmission
145 *
146 * 1) if the session is in Slow Start, the CWND has to be increased by 1
147 * MSS every unique received ACK
148 * 2) if the session is in Congestion Avoidance, the CWND has to be
149 * increased by MSS * MSS / CWND for every unique received ACK
150 */
151 static void batadv_tp_update_cwnd(struct batadv_tp_vars *tp_vars, u32 mss)
152 {
153 spin_lock_bh(&tp_vars->cwnd_lock);
154
155 /* slow start... */
156 if (tp_vars->cwnd <= tp_vars->ss_threshold) {
157 tp_vars->dec_cwnd = 0;
158 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss);
159 spin_unlock_bh(&tp_vars->cwnd_lock);
160 return;
161 }
162
163 /* increment CWND at least of 1 (section 3.1 of RFC5681) */
164 tp_vars->dec_cwnd += max_t(u32, 1U << 3,
165 ((mss * mss) << 6) / (tp_vars->cwnd << 3));
166 if (tp_vars->dec_cwnd < (mss << 3)) {
167 spin_unlock_bh(&tp_vars->cwnd_lock);
168 return;
169 }
170
171 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss);
172 tp_vars->dec_cwnd = 0;
173
174 spin_unlock_bh(&tp_vars->cwnd_lock);
175 }
176
177 /**
178 * batadv_tp_update_rto - calculate new retransmission timeout
179 * @tp_vars: the private data of the current TP meter session
180 * @new_rtt: new roundtrip time in msec
181 */
182 static void batadv_tp_update_rto(struct batadv_tp_vars *tp_vars,
183 u32 new_rtt)
184 {
185 long m = new_rtt;
186
187 /* RTT update
188 * Details in Section 2.2 and 2.3 of RFC6298
189 *
190 * It's tricky to understand. Don't lose hair please.
191 * Inspired by tcp_rtt_estimator() tcp_input.c
192 */
193 if (tp_vars->srtt != 0) {
194 m -= (tp_vars->srtt >> 3); /* m is now error in rtt est */
195 tp_vars->srtt += m; /* rtt = 7/8 srtt + 1/8 new */
196 if (m < 0)
197 m = -m;
198
199 m -= (tp_vars->rttvar >> 2);
200 tp_vars->rttvar += m; /* mdev ~= 3/4 rttvar + 1/4 new */
201 } else {
202 /* first measure getting in */
203 tp_vars->srtt = m << 3; /* take the measured time to be srtt */
204 tp_vars->rttvar = m << 1; /* new_rtt / 2 */
205 }
206
207 /* rto = srtt + 4 * rttvar.
208 * rttvar is scaled by 4, therefore doesn't need to be multiplied
209 */
210 tp_vars->rto = (tp_vars->srtt >> 3) + tp_vars->rttvar;
211 }
212
213 /**
214 * batadv_tp_batctl_notify - send client status result to client
215 * @reason: reason for tp meter session stop
216 * @dst: destination of tp_meter session
217 * @bat_priv: the bat priv with all the soft interface information
218 * @start_time: start of transmission in jiffies
219 * @total_sent: bytes acked to the receiver
220 * @cookie: cookie of tp_meter session
221 */
222 static void batadv_tp_batctl_notify(enum batadv_tp_meter_reason reason,
223 const u8 *dst, struct batadv_priv *bat_priv,
224 unsigned long start_time, u64 total_sent,
225 u32 cookie)
226 {
227 u32 test_time;
228 u8 result;
229 u32 total_bytes;
230
231 if (!batadv_tp_is_error(reason)) {
232 result = BATADV_TP_REASON_COMPLETE;
233 test_time = jiffies_to_msecs(jiffies - start_time);
234 total_bytes = total_sent;
235 } else {
236 result = reason;
237 test_time = 0;
238 total_bytes = 0;
239 }
240
241 batadv_netlink_tpmeter_notify(bat_priv, dst, result, test_time,
242 total_bytes, cookie);
243 }
244
245 /**
246 * batadv_tp_batctl_error_notify - send client error result to client
247 * @reason: reason for tp meter session stop
248 * @dst: destination of tp_meter session
249 * @bat_priv: the bat priv with all the soft interface information
250 * @cookie: cookie of tp_meter session
251 */
252 static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason,
253 const u8 *dst,
254 struct batadv_priv *bat_priv,
255 u32 cookie)
256 {
257 batadv_tp_batctl_notify(reason, dst, bat_priv, 0, 0, cookie);
258 }
259
260 /**
261 * batadv_tp_list_find - find a tp_vars object in the global list
262 * @bat_priv: the bat priv with all the soft interface information
263 * @dst: the other endpoint MAC address to look for
264 *
265 * Look for a tp_vars object matching dst as end_point and return it after
266 * having incremented the refcounter. Return NULL is not found
267 *
268 * Return: matching tp_vars or NULL when no tp_vars with @dst was found
269 */
270 static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
271 const u8 *dst)
272 {
273 struct batadv_tp_vars *pos, *tp_vars = NULL;
274
275 rcu_read_lock();
276 hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) {
277 if (!batadv_compare_eth(pos->other_end, dst))
278 continue;
279
280 /* most of the time this function is invoked during the normal
281 * process..it makes sens to pay more when the session is
282 * finished and to speed the process up during the measurement
283 */
284 if (unlikely(!kref_get_unless_zero(&pos->refcount)))
285 continue;
286
287 tp_vars = pos;
288 break;
289 }
290 rcu_read_unlock();
291
292 return tp_vars;
293 }
294
295 /**
296 * batadv_tp_list_find_session - find tp_vars session object in the global list
297 * @bat_priv: the bat priv with all the soft interface information
298 * @dst: the other endpoint MAC address to look for
299 * @session: session identifier
300 *
301 * Look for a tp_vars object matching dst as end_point, session as tp meter
302 * session and return it after having incremented the refcounter. Return NULL
303 * is not found
304 *
305 * Return: matching tp_vars or NULL when no tp_vars was found
306 */
307 static struct batadv_tp_vars *
308 batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst,
309 const u8 *session)
310 {
311 struct batadv_tp_vars *pos, *tp_vars = NULL;
312
313 rcu_read_lock();
314 hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) {
315 if (!batadv_compare_eth(pos->other_end, dst))
316 continue;
317
318 if (memcmp(pos->session, session, sizeof(pos->session)) != 0)
319 continue;
320
321 /* most of the time this function is invoked during the normal
322 * process..it makes sense to pay more when the session is
323 * finished and to speed the process up during the measurement
324 */
325 if (unlikely(!kref_get_unless_zero(&pos->refcount)))
326 continue;
327
328 tp_vars = pos;
329 break;
330 }
331 rcu_read_unlock();
332
333 return tp_vars;
334 }
335
336 /**
337 * batadv_tp_vars_release - release batadv_tp_vars from lists and queue for
338 * free after rcu grace period
339 * @ref: kref pointer of the batadv_tp_vars
340 */
341 static void batadv_tp_vars_release(struct kref *ref)
342 {
343 struct batadv_tp_vars *tp_vars;
344 struct batadv_tp_unacked *un, *safe;
345
346 tp_vars = container_of(ref, struct batadv_tp_vars, refcount);
347
348 /* lock should not be needed because this object is now out of any
349 * context!
350 */
351 spin_lock_bh(&tp_vars->unacked_lock);
352 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
353 list_del(&un->list);
354 kfree(un);
355 }
356 spin_unlock_bh(&tp_vars->unacked_lock);
357
358 kfree_rcu(tp_vars, rcu);
359 }
360
361 /**
362 * batadv_tp_vars_put - decrement the batadv_tp_vars refcounter and possibly
363 * release it
364 * @tp_vars: the private data of the current TP meter session to be free'd
365 */
366 static void batadv_tp_vars_put(struct batadv_tp_vars *tp_vars)
367 {
368 kref_put(&tp_vars->refcount, batadv_tp_vars_release);
369 }
370
371 /**
372 * batadv_tp_sender_cleanup - cleanup sender data and drop and timer
373 * @bat_priv: the bat priv with all the soft interface information
374 * @tp_vars: the private data of the current TP meter session to cleanup
375 */
376 static void batadv_tp_sender_cleanup(struct batadv_priv *bat_priv,
377 struct batadv_tp_vars *tp_vars)
378 {
379 cancel_delayed_work(&tp_vars->finish_work);
380
381 spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
382 hlist_del_rcu(&tp_vars->list);
383 spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
384
385 /* drop list reference */
386 batadv_tp_vars_put(tp_vars);
387
388 atomic_dec(&tp_vars->bat_priv->tp_num);
389
390 /* kill the timer and remove its reference */
391 del_timer_sync(&tp_vars->timer);
392 /* the worker might have rearmed itself therefore we kill it again. Note
393 * that if the worker should run again before invoking the following
394 * del_timer(), it would not re-arm itself once again because the status
395 * is OFF now
396 */
397 del_timer(&tp_vars->timer);
398 batadv_tp_vars_put(tp_vars);
399 }
400
401 /**
402 * batadv_tp_sender_end - print info about ended session and inform client
403 * @bat_priv: the bat priv with all the soft interface information
404 * @tp_vars: the private data of the current TP meter session
405 */
406 static void batadv_tp_sender_end(struct batadv_priv *bat_priv,
407 struct batadv_tp_vars *tp_vars)
408 {
409 u32 session_cookie;
410
411 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
412 "Test towards %pM finished..shutting down (reason=%d)\n",
413 tp_vars->other_end, tp_vars->reason);
414
415 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
416 "Last timing stats: SRTT=%ums RTTVAR=%ums RTO=%ums\n",
417 tp_vars->srtt >> 3, tp_vars->rttvar >> 2, tp_vars->rto);
418
419 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
420 "Final values: cwnd=%u ss_threshold=%u\n",
421 tp_vars->cwnd, tp_vars->ss_threshold);
422
423 session_cookie = batadv_tp_session_cookie(tp_vars->session,
424 tp_vars->icmp_uid);
425
426 batadv_tp_batctl_notify(tp_vars->reason,
427 tp_vars->other_end,
428 bat_priv,
429 tp_vars->start_time,
430 atomic64_read(&tp_vars->tot_sent),
431 session_cookie);
432 }
433
434 /**
435 * batadv_tp_sender_shutdown - let sender thread/timer stop gracefully
436 * @tp_vars: the private data of the current TP meter session
437 * @reason: reason for tp meter session stop
438 */
439 static void batadv_tp_sender_shutdown(struct batadv_tp_vars *tp_vars,
440 enum batadv_tp_meter_reason reason)
441 {
442 if (!atomic_dec_and_test(&tp_vars->sending))
443 return;
444
445 tp_vars->reason = reason;
446 }
447
448 /**
449 * batadv_tp_sender_finish - stop sender session after test_length was reached
450 * @work: delayed work reference of the related tp_vars
451 */
452 static void batadv_tp_sender_finish(struct work_struct *work)
453 {
454 struct delayed_work *delayed_work;
455 struct batadv_tp_vars *tp_vars;
456
457 delayed_work = to_delayed_work(work);
458 tp_vars = container_of(delayed_work, struct batadv_tp_vars,
459 finish_work);
460
461 batadv_tp_sender_shutdown(tp_vars, BATADV_TP_REASON_COMPLETE);
462 }
463
464 /**
465 * batadv_tp_reset_sender_timer - reschedule the sender timer
466 * @tp_vars: the private TP meter data for this session
467 *
468 * Reschedule the timer using tp_vars->rto as delay
469 */
470 static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars)
471 {
472 /* most of the time this function is invoked while normal packet
473 * reception...
474 */
475 if (unlikely(atomic_read(&tp_vars->sending) == 0))
476 /* timer ref will be dropped in batadv_tp_sender_cleanup */
477 return;
478
479 mod_timer(&tp_vars->timer, jiffies + msecs_to_jiffies(tp_vars->rto));
480 }
481
482 /**
483 * batadv_tp_sender_timeout - timer that fires in case of packet loss
484 * @arg: address of the related tp_vars
485 *
486 * If fired it means that there was packet loss.
487 * Switch to Slow Start, set the ss_threshold to half of the current cwnd and
488 * reset the cwnd to 3*MSS
489 */
490 static void batadv_tp_sender_timeout(unsigned long arg)
491 {
492 struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg;
493 struct batadv_priv *bat_priv = tp_vars->bat_priv;
494
495 if (atomic_read(&tp_vars->sending) == 0)
496 return;
497
498 /* if the user waited long enough...shutdown the test */
499 if (unlikely(tp_vars->rto >= BATADV_TP_MAX_RTO)) {
500 batadv_tp_sender_shutdown(tp_vars,
501 BATADV_TP_REASON_DST_UNREACHABLE);
502 return;
503 }
504
505 /* RTO exponential backoff
506 * Details in Section 5.5 of RFC6298
507 */
508 tp_vars->rto <<= 1;
509
510 spin_lock_bh(&tp_vars->cwnd_lock);
511
512 tp_vars->ss_threshold = tp_vars->cwnd >> 1;
513 if (tp_vars->ss_threshold < BATADV_TP_PLEN * 2)
514 tp_vars->ss_threshold = BATADV_TP_PLEN * 2;
515
516 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
517 "Meter: RTO fired during test towards %pM! cwnd=%u new ss_thr=%u, resetting last_sent to %u\n",
518 tp_vars->other_end, tp_vars->cwnd, tp_vars->ss_threshold,
519 atomic_read(&tp_vars->last_acked));
520
521 tp_vars->cwnd = BATADV_TP_PLEN * 3;
522
523 spin_unlock_bh(&tp_vars->cwnd_lock);
524
525 /* resend the non-ACKed packets.. */
526 tp_vars->last_sent = atomic_read(&tp_vars->last_acked);
527 wake_up(&tp_vars->more_bytes);
528
529 batadv_tp_reset_sender_timer(tp_vars);
530 }
531
532 /**
533 * batadv_tp_fill_prerandom - Fill buffer with prefetched random bytes
534 * @tp_vars: the private TP meter data for this session
535 * @buf: Buffer to fill with bytes
536 * @nbytes: amount of pseudorandom bytes
537 */
538 static void batadv_tp_fill_prerandom(struct batadv_tp_vars *tp_vars,
539 u8 *buf, size_t nbytes)
540 {
541 u32 local_offset;
542 size_t bytes_inbuf;
543 size_t to_copy;
544 size_t pos = 0;
545
546 spin_lock_bh(&tp_vars->prerandom_lock);
547 local_offset = tp_vars->prerandom_offset;
548 tp_vars->prerandom_offset += nbytes;
549 tp_vars->prerandom_offset %= sizeof(batadv_tp_prerandom);
550 spin_unlock_bh(&tp_vars->prerandom_lock);
551
552 while (nbytes) {
553 local_offset %= sizeof(batadv_tp_prerandom);
554 bytes_inbuf = sizeof(batadv_tp_prerandom) - local_offset;
555 to_copy = min(nbytes, bytes_inbuf);
556
557 memcpy(&buf[pos], &batadv_tp_prerandom[local_offset], to_copy);
558 pos += to_copy;
559 nbytes -= to_copy;
560 local_offset = 0;
561 }
562 }
563
564 /**
565 * batadv_tp_send_msg - send a single message
566 * @tp_vars: the private TP meter data for this session
567 * @src: source mac address
568 * @orig_node: the originator of the destination
569 * @seqno: sequence number of this packet
570 * @len: length of the entire packet
571 * @session: session identifier
572 * @uid: local ICMP "socket" index
573 * @timestamp: timestamp in jiffies which is replied in ack
574 *
575 * Create and send a single TP Meter message.
576 *
577 * Return: 0 on success, BATADV_TP_REASON_DST_UNREACHABLE if the destination is
578 * not reachable, BATADV_TP_REASON_MEMORY_ERROR if the packet couldn't be
579 * allocated
580 */
581 static int batadv_tp_send_msg(struct batadv_tp_vars *tp_vars, const u8 *src,
582 struct batadv_orig_node *orig_node,
583 u32 seqno, size_t len, const u8 *session,
584 int uid, u32 timestamp)
585 {
586 struct batadv_icmp_tp_packet *icmp;
587 struct sk_buff *skb;
588 int r;
589 u8 *data;
590 size_t data_len;
591
592 skb = netdev_alloc_skb_ip_align(NULL, len + ETH_HLEN);
593 if (unlikely(!skb))
594 return BATADV_TP_REASON_MEMORY_ERROR;
595
596 skb_reserve(skb, ETH_HLEN);
597 icmp = (struct batadv_icmp_tp_packet *)skb_put(skb, sizeof(*icmp));
598
599 /* fill the icmp header */
600 ether_addr_copy(icmp->dst, orig_node->orig);
601 ether_addr_copy(icmp->orig, src);
602 icmp->version = BATADV_COMPAT_VERSION;
603 icmp->packet_type = BATADV_ICMP;
604 icmp->ttl = BATADV_TTL;
605 icmp->msg_type = BATADV_TP;
606 icmp->uid = uid;
607
608 icmp->subtype = BATADV_TP_MSG;
609 memcpy(icmp->session, session, sizeof(icmp->session));
610 icmp->seqno = htonl(seqno);
611 icmp->timestamp = htonl(timestamp);
612
613 data_len = len - sizeof(*icmp);
614 data = (u8 *)skb_put(skb, data_len);
615 batadv_tp_fill_prerandom(tp_vars, data, data_len);
616
617 r = batadv_send_skb_to_orig(skb, orig_node, NULL);
618 if (r == -1)
619 kfree_skb(skb);
620
621 if (r == NET_XMIT_SUCCESS)
622 return 0;
623
624 return BATADV_TP_REASON_CANT_SEND;
625 }
626
627 /**
628 * batadv_tp_recv_ack - ACK receiving function
629 * @bat_priv: the bat priv with all the soft interface information
630 * @skb: the buffer containing the received packet
631 *
632 * Process a received TP ACK packet
633 */
634 static void batadv_tp_recv_ack(struct batadv_priv *bat_priv,
635 const struct sk_buff *skb)
636 {
637 struct batadv_hard_iface *primary_if = NULL;
638 struct batadv_orig_node *orig_node = NULL;
639 const struct batadv_icmp_tp_packet *icmp;
640 struct batadv_tp_vars *tp_vars;
641 size_t packet_len, mss;
642 u32 rtt, recv_ack, cwnd;
643 unsigned char *dev_addr;
644
645 packet_len = BATADV_TP_PLEN;
646 mss = BATADV_TP_PLEN;
647 packet_len += sizeof(struct batadv_unicast_packet);
648
649 icmp = (struct batadv_icmp_tp_packet *)skb->data;
650
651 /* find the tp_vars */
652 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
653 icmp->session);
654 if (unlikely(!tp_vars))
655 return;
656
657 if (unlikely(atomic_read(&tp_vars->sending) == 0))
658 goto out;
659
660 /* old ACK? silently drop it.. */
661 if (batadv_seq_before(ntohl(icmp->seqno),
662 (u32)atomic_read(&tp_vars->last_acked)))
663 goto out;
664
665 primary_if = batadv_primary_if_get_selected(bat_priv);
666 if (unlikely(!primary_if))
667 goto out;
668
669 orig_node = batadv_orig_hash_find(bat_priv, icmp->orig);
670 if (unlikely(!orig_node))
671 goto out;
672
673 /* update RTO with the new sampled RTT, if any */
674 rtt = jiffies_to_msecs(jiffies) - ntohl(icmp->timestamp);
675 if (icmp->timestamp && rtt)
676 batadv_tp_update_rto(tp_vars, rtt);
677
678 /* ACK for new data... reset the timer */
679 batadv_tp_reset_sender_timer(tp_vars);
680
681 recv_ack = ntohl(icmp->seqno);
682
683 /* check if this ACK is a duplicate */
684 if (atomic_read(&tp_vars->last_acked) == recv_ack) {
685 atomic_inc(&tp_vars->dup_acks);
686 if (atomic_read(&tp_vars->dup_acks) != 3)
687 goto out;
688
689 if (recv_ack >= tp_vars->recover)
690 goto out;
691
692 /* if this is the third duplicate ACK do Fast Retransmit */
693 batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr,
694 orig_node, recv_ack, packet_len,
695 icmp->session, icmp->uid,
696 jiffies_to_msecs(jiffies));
697
698 spin_lock_bh(&tp_vars->cwnd_lock);
699
700 /* Fast Recovery */
701 tp_vars->fast_recovery = true;
702 /* Set recover to the last outstanding seqno when Fast Recovery
703 * is entered. RFC6582, Section 3.2, step 1
704 */
705 tp_vars->recover = tp_vars->last_sent;
706 tp_vars->ss_threshold = tp_vars->cwnd >> 1;
707 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
708 "Meter: Fast Recovery, (cur cwnd=%u) ss_thr=%u last_sent=%u recv_ack=%u\n",
709 tp_vars->cwnd, tp_vars->ss_threshold,
710 tp_vars->last_sent, recv_ack);
711 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 3 * mss,
712 mss);
713 tp_vars->dec_cwnd = 0;
714 tp_vars->last_sent = recv_ack;
715
716 spin_unlock_bh(&tp_vars->cwnd_lock);
717 } else {
718 /* count the acked data */
719 atomic64_add(recv_ack - atomic_read(&tp_vars->last_acked),
720 &tp_vars->tot_sent);
721 /* reset the duplicate ACKs counter */
722 atomic_set(&tp_vars->dup_acks, 0);
723
724 if (tp_vars->fast_recovery) {
725 /* partial ACK */
726 if (batadv_seq_before(recv_ack, tp_vars->recover)) {
727 /* this is another hole in the window. React
728 * immediately as specified by NewReno (see
729 * Section 3.2 of RFC6582 for details)
730 */
731 dev_addr = primary_if->net_dev->dev_addr;
732 batadv_tp_send_msg(tp_vars, dev_addr,
733 orig_node, recv_ack,
734 packet_len, icmp->session,
735 icmp->uid,
736 jiffies_to_msecs(jiffies));
737 tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd,
738 mss, mss);
739 } else {
740 tp_vars->fast_recovery = false;
741 /* set cwnd to the value of ss_threshold at the
742 * moment that Fast Recovery was entered.
743 * RFC6582, Section 3.2, step 3
744 */
745 cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 0,
746 mss);
747 tp_vars->cwnd = cwnd;
748 }
749 goto move_twnd;
750 }
751
752 if (recv_ack - atomic_read(&tp_vars->last_acked) >= mss)
753 batadv_tp_update_cwnd(tp_vars, mss);
754 move_twnd:
755 /* move the Transmit Window */
756 atomic_set(&tp_vars->last_acked, recv_ack);
757 }
758
759 wake_up(&tp_vars->more_bytes);
760 out:
761 if (likely(primary_if))
762 batadv_hardif_put(primary_if);
763 if (likely(orig_node))
764 batadv_orig_node_put(orig_node);
765 if (likely(tp_vars))
766 batadv_tp_vars_put(tp_vars);
767 }
768
769 /**
770 * batadv_tp_avail - check if congestion window is not full
771 * @tp_vars: the private data of the current TP meter session
772 * @payload_len: size of the payload of a single message
773 *
774 * Return: true when congestion window is not full, false otherwise
775 */
776 static bool batadv_tp_avail(struct batadv_tp_vars *tp_vars,
777 size_t payload_len)
778 {
779 u32 win_left, win_limit;
780
781 win_limit = atomic_read(&tp_vars->last_acked) + tp_vars->cwnd;
782 win_left = win_limit - tp_vars->last_sent;
783
784 return win_left >= payload_len;
785 }
786
787 /**
788 * batadv_tp_wait_available - wait until congestion window becomes free or
789 * timeout is reached
790 * @tp_vars: the private data of the current TP meter session
791 * @plen: size of the payload of a single message
792 *
793 * Return: 0 if the condition evaluated to false after the timeout elapsed,
794 * 1 if the condition evaluated to true after the timeout elapsed, the
795 * remaining jiffies (at least 1) if the condition evaluated to true before
796 * the timeout elapsed, or -ERESTARTSYS if it was interrupted by a signal.
797 */
798 static int batadv_tp_wait_available(struct batadv_tp_vars *tp_vars, size_t plen)
799 {
800 int ret;
801
802 ret = wait_event_interruptible_timeout(tp_vars->more_bytes,
803 batadv_tp_avail(tp_vars, plen),
804 HZ / 10);
805
806 return ret;
807 }
808
809 /**
810 * batadv_tp_send - main sending thread of a tp meter session
811 * @arg: address of the related tp_vars
812 *
813 * Return: nothing, this function never returns
814 */
815 static int batadv_tp_send(void *arg)
816 {
817 struct batadv_tp_vars *tp_vars = arg;
818 struct batadv_priv *bat_priv = tp_vars->bat_priv;
819 struct batadv_hard_iface *primary_if = NULL;
820 struct batadv_orig_node *orig_node = NULL;
821 size_t payload_len, packet_len;
822 int err = 0;
823
824 if (unlikely(tp_vars->role != BATADV_TP_SENDER)) {
825 err = BATADV_TP_REASON_DST_UNREACHABLE;
826 tp_vars->reason = err;
827 goto out;
828 }
829
830 orig_node = batadv_orig_hash_find(bat_priv, tp_vars->other_end);
831 if (unlikely(!orig_node)) {
832 err = BATADV_TP_REASON_DST_UNREACHABLE;
833 tp_vars->reason = err;
834 goto out;
835 }
836
837 primary_if = batadv_primary_if_get_selected(bat_priv);
838 if (unlikely(!primary_if)) {
839 err = BATADV_TP_REASON_DST_UNREACHABLE;
840 tp_vars->reason = err;
841 goto out;
842 }
843
844 /* assume that all the hard_interfaces have a correctly
845 * configured MTU, so use the soft_iface MTU as MSS.
846 * This might not be true and in that case the fragmentation
847 * should be used.
848 * Now, try to send the packet as it is
849 */
850 payload_len = BATADV_TP_PLEN;
851 BUILD_BUG_ON(sizeof(struct batadv_icmp_tp_packet) > BATADV_TP_PLEN);
852
853 batadv_tp_reset_sender_timer(tp_vars);
854
855 /* queue the worker in charge of terminating the test */
856 queue_delayed_work(batadv_event_workqueue, &tp_vars->finish_work,
857 msecs_to_jiffies(tp_vars->test_length));
858
859 while (atomic_read(&tp_vars->sending) != 0) {
860 if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) {
861 batadv_tp_wait_available(tp_vars, payload_len);
862 continue;
863 }
864
865 /* to emulate normal unicast traffic, add to the payload len
866 * the size of the unicast header
867 */
868 packet_len = payload_len + sizeof(struct batadv_unicast_packet);
869
870 err = batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr,
871 orig_node, tp_vars->last_sent,
872 packet_len,
873 tp_vars->session, tp_vars->icmp_uid,
874 jiffies_to_msecs(jiffies));
875
876 /* something went wrong during the preparation/transmission */
877 if (unlikely(err && err != BATADV_TP_REASON_CANT_SEND)) {
878 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
879 "Meter: batadv_tp_send() cannot send packets (%d)\n",
880 err);
881 /* ensure nobody else tries to stop the thread now */
882 if (atomic_dec_and_test(&tp_vars->sending))
883 tp_vars->reason = err;
884 break;
885 }
886
887 /* right-shift the TWND */
888 if (!err)
889 tp_vars->last_sent += payload_len;
890
891 cond_resched();
892 }
893
894 out:
895 if (likely(primary_if))
896 batadv_hardif_put(primary_if);
897 if (likely(orig_node))
898 batadv_orig_node_put(orig_node);
899
900 batadv_tp_sender_end(bat_priv, tp_vars);
901 batadv_tp_sender_cleanup(bat_priv, tp_vars);
902
903 batadv_tp_vars_put(tp_vars);
904
905 do_exit(0);
906 }
907
908 /**
909 * batadv_tp_start_kthread - start new thread which manages the tp meter sender
910 * @tp_vars: the private data of the current TP meter session
911 */
912 static void batadv_tp_start_kthread(struct batadv_tp_vars *tp_vars)
913 {
914 struct task_struct *kthread;
915 struct batadv_priv *bat_priv = tp_vars->bat_priv;
916 u32 session_cookie;
917
918 kref_get(&tp_vars->refcount);
919 kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter");
920 if (IS_ERR(kthread)) {
921 session_cookie = batadv_tp_session_cookie(tp_vars->session,
922 tp_vars->icmp_uid);
923 pr_err("batadv: cannot create tp meter kthread\n");
924 batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
925 tp_vars->other_end,
926 bat_priv, session_cookie);
927
928 /* drop reserved reference for kthread */
929 batadv_tp_vars_put(tp_vars);
930
931 /* cleanup of failed tp meter variables */
932 batadv_tp_sender_cleanup(bat_priv, tp_vars);
933 return;
934 }
935
936 wake_up_process(kthread);
937 }
938
939 /**
940 * batadv_tp_start - start a new tp meter session
941 * @bat_priv: the bat priv with all the soft interface information
942 * @dst: the receiver MAC address
943 * @test_length: test length in milliseconds
944 * @cookie: session cookie
945 */
946 void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
947 u32 test_length, u32 *cookie)
948 {
949 struct batadv_tp_vars *tp_vars;
950 u8 session_id[2];
951 u8 icmp_uid;
952 u32 session_cookie;
953
954 get_random_bytes(session_id, sizeof(session_id));
955 get_random_bytes(&icmp_uid, 1);
956 session_cookie = batadv_tp_session_cookie(session_id, icmp_uid);
957 *cookie = session_cookie;
958
959 /* look for an already existing test towards this node */
960 spin_lock_bh(&bat_priv->tp_list_lock);
961 tp_vars = batadv_tp_list_find(bat_priv, dst);
962 if (tp_vars) {
963 spin_unlock_bh(&bat_priv->tp_list_lock);
964 batadv_tp_vars_put(tp_vars);
965 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
966 "Meter: test to or from the same node already ongoing, aborting\n");
967 batadv_tp_batctl_error_notify(BATADV_TP_REASON_ALREADY_ONGOING,
968 dst, bat_priv, session_cookie);
969 return;
970 }
971
972 if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
973 spin_unlock_bh(&bat_priv->tp_list_lock);
974 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
975 "Meter: too many ongoing sessions, aborting (SEND)\n");
976 batadv_tp_batctl_error_notify(BATADV_TP_REASON_TOO_MANY, dst,
977 bat_priv, session_cookie);
978 return;
979 }
980
981 tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
982 if (!tp_vars) {
983 spin_unlock_bh(&bat_priv->tp_list_lock);
984 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
985 "Meter: batadv_tp_start cannot allocate list elements\n");
986 batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
987 dst, bat_priv, session_cookie);
988 return;
989 }
990
991 /* initialize tp_vars */
992 ether_addr_copy(tp_vars->other_end, dst);
993 kref_init(&tp_vars->refcount);
994 tp_vars->role = BATADV_TP_SENDER;
995 atomic_set(&tp_vars->sending, 1);
996 memcpy(tp_vars->session, session_id, sizeof(session_id));
997 tp_vars->icmp_uid = icmp_uid;
998
999 tp_vars->last_sent = BATADV_TP_FIRST_SEQ;
1000 atomic_set(&tp_vars->last_acked, BATADV_TP_FIRST_SEQ);
1001 tp_vars->fast_recovery = false;
1002 tp_vars->recover = BATADV_TP_FIRST_SEQ;
1003
1004 /* initialise the CWND to 3*MSS (Section 3.1 in RFC5681).
1005 * For batman-adv the MSS is the size of the payload received by the
1006 * soft_interface, hence its MTU
1007 */
1008 tp_vars->cwnd = BATADV_TP_PLEN * 3;
1009 /* at the beginning initialise the SS threshold to the biggest possible
1010 * window size, hence the AWND size
1011 */
1012 tp_vars->ss_threshold = BATADV_TP_AWND;
1013
1014 /* RTO initial value is 3 seconds.
1015 * Details in Section 2.1 of RFC6298
1016 */
1017 tp_vars->rto = 1000;
1018 tp_vars->srtt = 0;
1019 tp_vars->rttvar = 0;
1020
1021 atomic64_set(&tp_vars->tot_sent, 0);
1022
1023 kref_get(&tp_vars->refcount);
1024 setup_timer(&tp_vars->timer, batadv_tp_sender_timeout,
1025 (unsigned long)tp_vars);
1026
1027 tp_vars->bat_priv = bat_priv;
1028 tp_vars->start_time = jiffies;
1029
1030 init_waitqueue_head(&tp_vars->more_bytes);
1031
1032 spin_lock_init(&tp_vars->unacked_lock);
1033 INIT_LIST_HEAD(&tp_vars->unacked_list);
1034
1035 spin_lock_init(&tp_vars->cwnd_lock);
1036
1037 tp_vars->prerandom_offset = 0;
1038 spin_lock_init(&tp_vars->prerandom_lock);
1039
1040 kref_get(&tp_vars->refcount);
1041 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1042 spin_unlock_bh(&bat_priv->tp_list_lock);
1043
1044 tp_vars->test_length = test_length;
1045 if (!tp_vars->test_length)
1046 tp_vars->test_length = BATADV_TP_DEF_TEST_LENGTH;
1047
1048 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1049 "Meter: starting throughput meter towards %pM (length=%ums)\n",
1050 dst, test_length);
1051
1052 /* init work item for finished tp tests */
1053 INIT_DELAYED_WORK(&tp_vars->finish_work, batadv_tp_sender_finish);
1054
1055 /* start tp kthread. This way the write() call issued from userspace can
1056 * happily return and avoid to block
1057 */
1058 batadv_tp_start_kthread(tp_vars);
1059
1060 /* don't return reference to new tp_vars */
1061 batadv_tp_vars_put(tp_vars);
1062 }
1063
1064 /**
1065 * batadv_tp_stop - stop currently running tp meter session
1066 * @bat_priv: the bat priv with all the soft interface information
1067 * @dst: the receiver MAC address
1068 * @return_value: reason for tp meter session stop
1069 */
1070 void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst,
1071 u8 return_value)
1072 {
1073 struct batadv_orig_node *orig_node;
1074 struct batadv_tp_vars *tp_vars;
1075
1076 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1077 "Meter: stopping test towards %pM\n", dst);
1078
1079 orig_node = batadv_orig_hash_find(bat_priv, dst);
1080 if (!orig_node)
1081 return;
1082
1083 tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig);
1084 if (!tp_vars) {
1085 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1086 "Meter: trying to interrupt an already over connection\n");
1087 goto out;
1088 }
1089
1090 batadv_tp_sender_shutdown(tp_vars, return_value);
1091 batadv_tp_vars_put(tp_vars);
1092 out:
1093 batadv_orig_node_put(orig_node);
1094 }
1095
1096 /**
1097 * batadv_tp_reset_receiver_timer - reset the receiver shutdown timer
1098 * @tp_vars: the private data of the current TP meter session
1099 *
1100 * start the receiver shutdown timer or reset it if already started
1101 */
1102 static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars)
1103 {
1104 mod_timer(&tp_vars->timer,
1105 jiffies + msecs_to_jiffies(BATADV_TP_RECV_TIMEOUT));
1106 }
1107
1108 /**
1109 * batadv_tp_receiver_shutdown - stop a tp meter receiver when timeout is
1110 * reached without received ack
1111 * @arg: address of the related tp_vars
1112 */
1113 static void batadv_tp_receiver_shutdown(unsigned long arg)
1114 {
1115 struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg;
1116 struct batadv_tp_unacked *un, *safe;
1117 struct batadv_priv *bat_priv;
1118
1119 bat_priv = tp_vars->bat_priv;
1120
1121 /* if there is recent activity rearm the timer */
1122 if (!batadv_has_timed_out(tp_vars->last_recv_time,
1123 BATADV_TP_RECV_TIMEOUT)) {
1124 /* reset the receiver shutdown timer */
1125 batadv_tp_reset_receiver_timer(tp_vars);
1126 return;
1127 }
1128
1129 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1130 "Shutting down for inactivity (more than %dms) from %pM\n",
1131 BATADV_TP_RECV_TIMEOUT, tp_vars->other_end);
1132
1133 spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
1134 hlist_del_rcu(&tp_vars->list);
1135 spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
1136
1137 /* drop list reference */
1138 batadv_tp_vars_put(tp_vars);
1139
1140 atomic_dec(&bat_priv->tp_num);
1141
1142 spin_lock_bh(&tp_vars->unacked_lock);
1143 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
1144 list_del(&un->list);
1145 kfree(un);
1146 }
1147 spin_unlock_bh(&tp_vars->unacked_lock);
1148
1149 /* drop reference of timer */
1150 batadv_tp_vars_put(tp_vars);
1151 }
1152
1153 /**
1154 * batadv_tp_send_ack - send an ACK packet
1155 * @bat_priv: the bat priv with all the soft interface information
1156 * @dst: the mac address of the destination originator
1157 * @seq: the sequence number to ACK
1158 * @timestamp: the timestamp to echo back in the ACK
1159 * @session: session identifier
1160 * @socket_index: local ICMP socket identifier
1161 *
1162 * Return: 0 on success, a positive integer representing the reason of the
1163 * failure otherwise
1164 */
1165 static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst,
1166 u32 seq, __be32 timestamp, const u8 *session,
1167 int socket_index)
1168 {
1169 struct batadv_hard_iface *primary_if = NULL;
1170 struct batadv_orig_node *orig_node;
1171 struct batadv_icmp_tp_packet *icmp;
1172 struct sk_buff *skb;
1173 int r, ret;
1174
1175 orig_node = batadv_orig_hash_find(bat_priv, dst);
1176 if (unlikely(!orig_node)) {
1177 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1178 goto out;
1179 }
1180
1181 primary_if = batadv_primary_if_get_selected(bat_priv);
1182 if (unlikely(!primary_if)) {
1183 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1184 goto out;
1185 }
1186
1187 skb = netdev_alloc_skb_ip_align(NULL, sizeof(*icmp) + ETH_HLEN);
1188 if (unlikely(!skb)) {
1189 ret = BATADV_TP_REASON_MEMORY_ERROR;
1190 goto out;
1191 }
1192
1193 skb_reserve(skb, ETH_HLEN);
1194 icmp = (struct batadv_icmp_tp_packet *)skb_put(skb, sizeof(*icmp));
1195 icmp->packet_type = BATADV_ICMP;
1196 icmp->version = BATADV_COMPAT_VERSION;
1197 icmp->ttl = BATADV_TTL;
1198 icmp->msg_type = BATADV_TP;
1199 ether_addr_copy(icmp->dst, orig_node->orig);
1200 ether_addr_copy(icmp->orig, primary_if->net_dev->dev_addr);
1201 icmp->uid = socket_index;
1202
1203 icmp->subtype = BATADV_TP_ACK;
1204 memcpy(icmp->session, session, sizeof(icmp->session));
1205 icmp->seqno = htonl(seq);
1206 icmp->timestamp = timestamp;
1207
1208 /* send the ack */
1209 r = batadv_send_skb_to_orig(skb, orig_node, NULL);
1210 if (r == -1)
1211 kfree_skb(skb);
1212
1213 if (unlikely(r < 0) || (r == NET_XMIT_DROP)) {
1214 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1215 goto out;
1216 }
1217 ret = 0;
1218
1219 out:
1220 if (likely(orig_node))
1221 batadv_orig_node_put(orig_node);
1222 if (likely(primary_if))
1223 batadv_hardif_put(primary_if);
1224
1225 return ret;
1226 }
1227
1228 /**
1229 * batadv_tp_handle_out_of_order - store an out of order packet
1230 * @tp_vars: the private data of the current TP meter session
1231 * @skb: the buffer containing the received packet
1232 *
1233 * Store the out of order packet in the unacked list for late processing. This
1234 * packets are kept in this list so that they can be ACKed at once as soon as
1235 * all the previous packets have been received
1236 *
1237 * Return: true if the packed has been successfully processed, false otherwise
1238 */
1239 static bool batadv_tp_handle_out_of_order(struct batadv_tp_vars *tp_vars,
1240 const struct sk_buff *skb)
1241 {
1242 const struct batadv_icmp_tp_packet *icmp;
1243 struct batadv_tp_unacked *un, *new;
1244 u32 payload_len;
1245 bool added = false;
1246
1247 new = kmalloc(sizeof(*new), GFP_ATOMIC);
1248 if (unlikely(!new))
1249 return false;
1250
1251 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1252
1253 new->seqno = ntohl(icmp->seqno);
1254 payload_len = skb->len - sizeof(struct batadv_unicast_packet);
1255 new->len = payload_len;
1256
1257 spin_lock_bh(&tp_vars->unacked_lock);
1258 /* if the list is empty immediately attach this new object */
1259 if (list_empty(&tp_vars->unacked_list)) {
1260 list_add(&new->list, &tp_vars->unacked_list);
1261 goto out;
1262 }
1263
1264 /* otherwise loop over the list and either drop the packet because this
1265 * is a duplicate or store it at the right position.
1266 *
1267 * The iteration is done in the reverse way because it is likely that
1268 * the last received packet (the one being processed now) has a bigger
1269 * seqno than all the others already stored.
1270 */
1271 list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) {
1272 /* check for duplicates */
1273 if (new->seqno == un->seqno) {
1274 if (new->len > un->len)
1275 un->len = new->len;
1276 kfree(new);
1277 added = true;
1278 break;
1279 }
1280
1281 /* look for the right position */
1282 if (batadv_seq_before(new->seqno, un->seqno))
1283 continue;
1284
1285 /* as soon as an entry having a bigger seqno is found, the new
1286 * one is attached _after_ it. In this way the list is kept in
1287 * ascending order
1288 */
1289 list_add_tail(&new->list, &un->list);
1290 added = true;
1291 break;
1292 }
1293
1294 /* received packet with smallest seqno out of order; add it to front */
1295 if (!added)
1296 list_add(&new->list, &tp_vars->unacked_list);
1297
1298 out:
1299 spin_unlock_bh(&tp_vars->unacked_lock);
1300
1301 return true;
1302 }
1303
1304 /**
1305 * batadv_tp_ack_unordered - update number received bytes in current stream
1306 * without gaps
1307 * @tp_vars: the private data of the current TP meter session
1308 */
1309 static void batadv_tp_ack_unordered(struct batadv_tp_vars *tp_vars)
1310 {
1311 struct batadv_tp_unacked *un, *safe;
1312 u32 to_ack;
1313
1314 /* go through the unacked packet list and possibly ACK them as
1315 * well
1316 */
1317 spin_lock_bh(&tp_vars->unacked_lock);
1318 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
1319 /* the list is ordered, therefore it is possible to stop as soon
1320 * there is a gap between the last acked seqno and the seqno of
1321 * the packet under inspection
1322 */
1323 if (batadv_seq_before(tp_vars->last_recv, un->seqno))
1324 break;
1325
1326 to_ack = un->seqno + un->len - tp_vars->last_recv;
1327
1328 if (batadv_seq_before(tp_vars->last_recv, un->seqno + un->len))
1329 tp_vars->last_recv += to_ack;
1330
1331 list_del(&un->list);
1332 kfree(un);
1333 }
1334 spin_unlock_bh(&tp_vars->unacked_lock);
1335 }
1336
1337 /**
1338 * batadv_tp_init_recv - return matching or create new receiver tp_vars
1339 * @bat_priv: the bat priv with all the soft interface information
1340 * @icmp: received icmp tp msg
1341 *
1342 * Return: corresponding tp_vars or NULL on errors
1343 */
1344 static struct batadv_tp_vars *
1345 batadv_tp_init_recv(struct batadv_priv *bat_priv,
1346 const struct batadv_icmp_tp_packet *icmp)
1347 {
1348 struct batadv_tp_vars *tp_vars;
1349
1350 spin_lock_bh(&bat_priv->tp_list_lock);
1351 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
1352 icmp->session);
1353 if (tp_vars)
1354 goto out_unlock;
1355
1356 if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
1357 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1358 "Meter: too many ongoing sessions, aborting (RECV)\n");
1359 goto out_unlock;
1360 }
1361
1362 tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
1363 if (!tp_vars)
1364 goto out_unlock;
1365
1366 ether_addr_copy(tp_vars->other_end, icmp->orig);
1367 tp_vars->role = BATADV_TP_RECEIVER;
1368 memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session));
1369 tp_vars->last_recv = BATADV_TP_FIRST_SEQ;
1370 tp_vars->bat_priv = bat_priv;
1371 kref_init(&tp_vars->refcount);
1372
1373 spin_lock_init(&tp_vars->unacked_lock);
1374 INIT_LIST_HEAD(&tp_vars->unacked_list);
1375
1376 kref_get(&tp_vars->refcount);
1377 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1378
1379 kref_get(&tp_vars->refcount);
1380 setup_timer(&tp_vars->timer, batadv_tp_receiver_shutdown,
1381 (unsigned long)tp_vars);
1382
1383 batadv_tp_reset_receiver_timer(tp_vars);
1384
1385 out_unlock:
1386 spin_unlock_bh(&bat_priv->tp_list_lock);
1387
1388 return tp_vars;
1389 }
1390
1391 /**
1392 * batadv_tp_recv_msg - process a single data message
1393 * @bat_priv: the bat priv with all the soft interface information
1394 * @skb: the buffer containing the received packet
1395 *
1396 * Process a received TP MSG packet
1397 */
1398 static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
1399 const struct sk_buff *skb)
1400 {
1401 const struct batadv_icmp_tp_packet *icmp;
1402 struct batadv_tp_vars *tp_vars;
1403 size_t packet_size;
1404 u32 seqno;
1405
1406 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1407
1408 seqno = ntohl(icmp->seqno);
1409 /* check if this is the first seqno. This means that if the
1410 * first packet is lost, the tp meter does not work anymore!
1411 */
1412 if (seqno == BATADV_TP_FIRST_SEQ) {
1413 tp_vars = batadv_tp_init_recv(bat_priv, icmp);
1414 if (!tp_vars) {
1415 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1416 "Meter: seqno != BATADV_TP_FIRST_SEQ cannot initiate connection\n");
1417 goto out;
1418 }
1419 } else {
1420 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
1421 icmp->session);
1422 if (!tp_vars) {
1423 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1424 "Unexpected packet from %pM!\n",
1425 icmp->orig);
1426 goto out;
1427 }
1428 }
1429
1430 if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) {
1431 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1432 "Meter: dropping packet: not expected (role=%u)\n",
1433 tp_vars->role);
1434 goto out;
1435 }
1436
1437 tp_vars->last_recv_time = jiffies;
1438
1439 /* if the packet is a duplicate, it may be the case that an ACK has been
1440 * lost. Resend the ACK
1441 */
1442 if (batadv_seq_before(seqno, tp_vars->last_recv))
1443 goto send_ack;
1444
1445 /* if the packet is out of order enqueue it */
1446 if (ntohl(icmp->seqno) != tp_vars->last_recv) {
1447 /* exit immediately (and do not send any ACK) if the packet has
1448 * not been enqueued correctly
1449 */
1450 if (!batadv_tp_handle_out_of_order(tp_vars, skb))
1451 goto out;
1452
1453 /* send a duplicate ACK */
1454 goto send_ack;
1455 }
1456
1457 /* if everything was fine count the ACKed bytes */
1458 packet_size = skb->len - sizeof(struct batadv_unicast_packet);
1459 tp_vars->last_recv += packet_size;
1460
1461 /* check if this ordered message filled a gap.... */
1462 batadv_tp_ack_unordered(tp_vars);
1463
1464 send_ack:
1465 /* send the ACK. If the received packet was out of order, the ACK that
1466 * is going to be sent is a duplicate (the sender will count them and
1467 * possibly enter Fast Retransmit as soon as it has reached 3)
1468 */
1469 batadv_tp_send_ack(bat_priv, icmp->orig, tp_vars->last_recv,
1470 icmp->timestamp, icmp->session, icmp->uid);
1471 out:
1472 if (likely(tp_vars))
1473 batadv_tp_vars_put(tp_vars);
1474 }
1475
1476 /**
1477 * batadv_tp_meter_recv - main TP Meter receiving function
1478 * @bat_priv: the bat priv with all the soft interface information
1479 * @skb: the buffer containing the received packet
1480 */
1481 void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb)
1482 {
1483 struct batadv_icmp_tp_packet *icmp;
1484
1485 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1486
1487 switch (icmp->subtype) {
1488 case BATADV_TP_MSG:
1489 batadv_tp_recv_msg(bat_priv, skb);
1490 break;
1491 case BATADV_TP_ACK:
1492 batadv_tp_recv_ack(bat_priv, skb);
1493 break;
1494 default:
1495 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1496 "Received unknown TP Metric packet type %u\n",
1497 icmp->subtype);
1498 }
1499 consume_skb(skb);
1500 }
1501
1502 /**
1503 * batadv_tp_meter_init - initialize global tp_meter structures
1504 */
1505 void batadv_tp_meter_init(void)
1506 {
1507 get_random_bytes(batadv_tp_prerandom, sizeof(batadv_tp_prerandom));
1508 }
1509
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