blob: 2333777f919d8ef3e28055733e0d55b64d3ecff3 [file] [log] [blame]
Antonio Quartulli33a3bb42016-05-05 13:09:43 +02001/* 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
96static 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 */
105static 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 */
128static 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 */
151static 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 */
182static 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 */
222static 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 */
252static 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 */
270static 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 */
307static struct batadv_tp_vars *
308batadv_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 */
341static 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 */
366static 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 */
376static 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 */
406static 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 */
439static 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 */
452static 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 */
470static 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 */
490static 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 */
538static 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 */
581static 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 */
634static 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);
754move_twnd:
755 /* move the Transmit Window */
756 atomic_set(&tp_vars->last_acked, recv_ack);
757 }
758
759 wake_up(&tp_vars->more_bytes);
760out:
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 */
776static 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 */
798static 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 */
815static 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 goto out;
841 }
842
843 /* assume that all the hard_interfaces have a correctly
844 * configured MTU, so use the soft_iface MTU as MSS.
845 * This might not be true and in that case the fragmentation
846 * should be used.
847 * Now, try to send the packet as it is
848 */
849 payload_len = BATADV_TP_PLEN;
850 BUILD_BUG_ON(sizeof(struct batadv_icmp_tp_packet) > BATADV_TP_PLEN);
851
852 batadv_tp_reset_sender_timer(tp_vars);
853
854 /* queue the worker in charge of terminating the test */
855 queue_delayed_work(batadv_event_workqueue, &tp_vars->finish_work,
856 msecs_to_jiffies(tp_vars->test_length));
857
858 while (atomic_read(&tp_vars->sending) != 0) {
859 if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) {
860 batadv_tp_wait_available(tp_vars, payload_len);
861 continue;
862 }
863
864 /* to emulate normal unicast traffic, add to the payload len
865 * the size of the unicast header
866 */
867 packet_len = payload_len + sizeof(struct batadv_unicast_packet);
868
869 err = batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr,
870 orig_node, tp_vars->last_sent,
871 packet_len,
872 tp_vars->session, tp_vars->icmp_uid,
873 jiffies_to_msecs(jiffies));
874
875 /* something went wrong during the preparation/transmission */
876 if (unlikely(err && err != BATADV_TP_REASON_CANT_SEND)) {
877 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
878 "Meter: batadv_tp_send() cannot send packets (%d)\n",
879 err);
880 /* ensure nobody else tries to stop the thread now */
881 if (atomic_dec_and_test(&tp_vars->sending))
882 tp_vars->reason = err;
883 break;
884 }
885
886 /* right-shift the TWND */
887 if (!err)
888 tp_vars->last_sent += payload_len;
889
890 cond_resched();
891 }
892
893out:
894 if (likely(primary_if))
895 batadv_hardif_put(primary_if);
896 if (likely(orig_node))
897 batadv_orig_node_put(orig_node);
898
899 batadv_tp_sender_end(bat_priv, tp_vars);
900 batadv_tp_sender_cleanup(bat_priv, tp_vars);
901
902 batadv_tp_vars_put(tp_vars);
903
904 do_exit(0);
905}
906
907/**
908 * batadv_tp_start_kthread - start new thread which manages the tp meter sender
909 * @tp_vars: the private data of the current TP meter session
910 */
911static void batadv_tp_start_kthread(struct batadv_tp_vars *tp_vars)
912{
913 struct task_struct *kthread;
914 struct batadv_priv *bat_priv = tp_vars->bat_priv;
915 u32 session_cookie;
916
917 kref_get(&tp_vars->refcount);
918 kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter");
919 if (IS_ERR(kthread)) {
920 session_cookie = batadv_tp_session_cookie(tp_vars->session,
921 tp_vars->icmp_uid);
922 pr_err("batadv: cannot create tp meter kthread\n");
923 batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
924 tp_vars->other_end,
925 bat_priv, session_cookie);
926
927 /* drop reserved reference for kthread */
928 batadv_tp_vars_put(tp_vars);
929
930 /* cleanup of failed tp meter variables */
931 batadv_tp_sender_cleanup(bat_priv, tp_vars);
932 return;
933 }
934
935 wake_up_process(kthread);
936}
937
938/**
939 * batadv_tp_start - start a new tp meter session
940 * @bat_priv: the bat priv with all the soft interface information
941 * @dst: the receiver MAC address
942 * @test_length: test length in milliseconds
943 * @cookie: session cookie
944 */
945void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
946 u32 test_length, u32 *cookie)
947{
948 struct batadv_tp_vars *tp_vars;
949 u8 session_id[2];
950 u8 icmp_uid;
951 u32 session_cookie;
952
953 get_random_bytes(session_id, sizeof(session_id));
954 get_random_bytes(&icmp_uid, 1);
955 session_cookie = batadv_tp_session_cookie(session_id, icmp_uid);
956 *cookie = session_cookie;
957
958 /* look for an already existing test towards this node */
959 spin_lock_bh(&bat_priv->tp_list_lock);
960 tp_vars = batadv_tp_list_find(bat_priv, dst);
961 if (tp_vars) {
962 spin_unlock_bh(&bat_priv->tp_list_lock);
963 batadv_tp_vars_put(tp_vars);
964 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
965 "Meter: test to or from the same node already ongoing, aborting\n");
966 batadv_tp_batctl_error_notify(BATADV_TP_REASON_ALREADY_ONGOING,
967 dst, bat_priv, session_cookie);
968 return;
969 }
970
971 if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
972 spin_unlock_bh(&bat_priv->tp_list_lock);
973 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
974 "Meter: too many ongoing sessions, aborting (SEND)\n");
975 batadv_tp_batctl_error_notify(BATADV_TP_REASON_TOO_MANY, dst,
976 bat_priv, session_cookie);
977 return;
978 }
979
980 tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
981 if (!tp_vars) {
982 spin_unlock_bh(&bat_priv->tp_list_lock);
983 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
984 "Meter: batadv_tp_start cannot allocate list elements\n");
985 batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
986 dst, bat_priv, session_cookie);
987 return;
988 }
989
990 /* initialize tp_vars */
991 ether_addr_copy(tp_vars->other_end, dst);
992 kref_init(&tp_vars->refcount);
993 tp_vars->role = BATADV_TP_SENDER;
994 atomic_set(&tp_vars->sending, 1);
995 memcpy(tp_vars->session, session_id, sizeof(session_id));
996 tp_vars->icmp_uid = icmp_uid;
997
998 tp_vars->last_sent = BATADV_TP_FIRST_SEQ;
999 atomic_set(&tp_vars->last_acked, BATADV_TP_FIRST_SEQ);
1000 tp_vars->fast_recovery = false;
1001 tp_vars->recover = BATADV_TP_FIRST_SEQ;
1002
1003 /* initialise the CWND to 3*MSS (Section 3.1 in RFC5681).
1004 * For batman-adv the MSS is the size of the payload received by the
1005 * soft_interface, hence its MTU
1006 */
1007 tp_vars->cwnd = BATADV_TP_PLEN * 3;
1008 /* at the beginning initialise the SS threshold to the biggest possible
1009 * window size, hence the AWND size
1010 */
1011 tp_vars->ss_threshold = BATADV_TP_AWND;
1012
1013 /* RTO initial value is 3 seconds.
1014 * Details in Section 2.1 of RFC6298
1015 */
1016 tp_vars->rto = 1000;
1017 tp_vars->srtt = 0;
1018 tp_vars->rttvar = 0;
1019
1020 atomic64_set(&tp_vars->tot_sent, 0);
1021
1022 kref_get(&tp_vars->refcount);
1023 setup_timer(&tp_vars->timer, batadv_tp_sender_timeout,
1024 (unsigned long)tp_vars);
1025
1026 tp_vars->bat_priv = bat_priv;
1027 tp_vars->start_time = jiffies;
1028
1029 init_waitqueue_head(&tp_vars->more_bytes);
1030
1031 spin_lock_init(&tp_vars->unacked_lock);
1032 INIT_LIST_HEAD(&tp_vars->unacked_list);
1033
1034 spin_lock_init(&tp_vars->cwnd_lock);
1035
1036 tp_vars->prerandom_offset = 0;
1037 spin_lock_init(&tp_vars->prerandom_lock);
1038
1039 kref_get(&tp_vars->refcount);
1040 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1041 spin_unlock_bh(&bat_priv->tp_list_lock);
1042
1043 tp_vars->test_length = test_length;
1044 if (!tp_vars->test_length)
1045 tp_vars->test_length = BATADV_TP_DEF_TEST_LENGTH;
1046
1047 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1048 "Meter: starting throughput meter towards %pM (length=%ums)\n",
1049 dst, test_length);
1050
1051 /* init work item for finished tp tests */
1052 INIT_DELAYED_WORK(&tp_vars->finish_work, batadv_tp_sender_finish);
1053
1054 /* start tp kthread. This way the write() call issued from userspace can
1055 * happily return and avoid to block
1056 */
1057 batadv_tp_start_kthread(tp_vars);
1058
1059 /* don't return reference to new tp_vars */
1060 batadv_tp_vars_put(tp_vars);
1061}
1062
1063/**
1064 * batadv_tp_stop - stop currently running tp meter session
1065 * @bat_priv: the bat priv with all the soft interface information
1066 * @dst: the receiver MAC address
1067 * @return_value: reason for tp meter session stop
1068 */
1069void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst,
1070 u8 return_value)
1071{
1072 struct batadv_orig_node *orig_node;
1073 struct batadv_tp_vars *tp_vars;
1074
1075 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1076 "Meter: stopping test towards %pM\n", dst);
1077
1078 orig_node = batadv_orig_hash_find(bat_priv, dst);
1079 if (!orig_node)
1080 return;
1081
1082 tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig);
1083 if (!tp_vars) {
1084 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1085 "Meter: trying to interrupt an already over connection\n");
1086 goto out;
1087 }
1088
1089 batadv_tp_sender_shutdown(tp_vars, return_value);
1090 batadv_tp_vars_put(tp_vars);
1091out:
1092 batadv_orig_node_put(orig_node);
1093}
1094
1095/**
1096 * batadv_tp_reset_receiver_timer - reset the receiver shutdown timer
1097 * @tp_vars: the private data of the current TP meter session
1098 *
1099 * start the receiver shutdown timer or reset it if already started
1100 */
1101static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars)
1102{
1103 mod_timer(&tp_vars->timer,
1104 jiffies + msecs_to_jiffies(BATADV_TP_RECV_TIMEOUT));
1105}
1106
1107/**
1108 * batadv_tp_receiver_shutdown - stop a tp meter receiver when timeout is
1109 * reached without received ack
1110 * @arg: address of the related tp_vars
1111 */
1112static void batadv_tp_receiver_shutdown(unsigned long arg)
1113{
1114 struct batadv_tp_vars *tp_vars = (struct batadv_tp_vars *)arg;
1115 struct batadv_tp_unacked *un, *safe;
1116 struct batadv_priv *bat_priv;
1117
1118 bat_priv = tp_vars->bat_priv;
1119
1120 /* if there is recent activity rearm the timer */
1121 if (!batadv_has_timed_out(tp_vars->last_recv_time,
1122 BATADV_TP_RECV_TIMEOUT)) {
1123 /* reset the receiver shutdown timer */
1124 batadv_tp_reset_receiver_timer(tp_vars);
1125 return;
1126 }
1127
1128 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1129 "Shutting down for inactivity (more than %dms) from %pM\n",
1130 BATADV_TP_RECV_TIMEOUT, tp_vars->other_end);
1131
1132 spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
1133 hlist_del_rcu(&tp_vars->list);
1134 spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
1135
1136 /* drop list reference */
1137 batadv_tp_vars_put(tp_vars);
1138
1139 atomic_dec(&bat_priv->tp_num);
1140
1141 spin_lock_bh(&tp_vars->unacked_lock);
1142 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
1143 list_del(&un->list);
1144 kfree(un);
1145 }
1146 spin_unlock_bh(&tp_vars->unacked_lock);
1147
1148 /* drop reference of timer */
1149 batadv_tp_vars_put(tp_vars);
1150}
1151
1152/**
1153 * batadv_tp_send_ack - send an ACK packet
1154 * @bat_priv: the bat priv with all the soft interface information
1155 * @dst: the mac address of the destination originator
1156 * @seq: the sequence number to ACK
1157 * @timestamp: the timestamp to echo back in the ACK
1158 * @session: session identifier
1159 * @socket_index: local ICMP socket identifier
1160 *
1161 * Return: 0 on success, a positive integer representing the reason of the
1162 * failure otherwise
1163 */
1164static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst,
1165 u32 seq, __be32 timestamp, const u8 *session,
1166 int socket_index)
1167{
1168 struct batadv_hard_iface *primary_if = NULL;
1169 struct batadv_orig_node *orig_node;
1170 struct batadv_icmp_tp_packet *icmp;
1171 struct sk_buff *skb;
1172 int r, ret;
1173
1174 orig_node = batadv_orig_hash_find(bat_priv, dst);
1175 if (unlikely(!orig_node)) {
1176 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1177 goto out;
1178 }
1179
1180 primary_if = batadv_primary_if_get_selected(bat_priv);
1181 if (unlikely(!primary_if)) {
1182 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1183 goto out;
1184 }
1185
1186 skb = netdev_alloc_skb_ip_align(NULL, sizeof(*icmp) + ETH_HLEN);
1187 if (unlikely(!skb)) {
1188 ret = BATADV_TP_REASON_MEMORY_ERROR;
1189 goto out;
1190 }
1191
1192 skb_reserve(skb, ETH_HLEN);
1193 icmp = (struct batadv_icmp_tp_packet *)skb_put(skb, sizeof(*icmp));
1194 icmp->packet_type = BATADV_ICMP;
1195 icmp->version = BATADV_COMPAT_VERSION;
1196 icmp->ttl = BATADV_TTL;
1197 icmp->msg_type = BATADV_TP;
1198 ether_addr_copy(icmp->dst, orig_node->orig);
1199 ether_addr_copy(icmp->orig, primary_if->net_dev->dev_addr);
1200 icmp->uid = socket_index;
1201
1202 icmp->subtype = BATADV_TP_ACK;
1203 memcpy(icmp->session, session, sizeof(icmp->session));
1204 icmp->seqno = htonl(seq);
1205 icmp->timestamp = timestamp;
1206
1207 /* send the ack */
1208 r = batadv_send_skb_to_orig(skb, orig_node, NULL);
1209 if (r == -1)
1210 kfree_skb(skb);
1211
1212 if (unlikely(r < 0) || (r == NET_XMIT_DROP)) {
1213 ret = BATADV_TP_REASON_DST_UNREACHABLE;
1214 goto out;
1215 }
1216 ret = 0;
1217
1218out:
1219 if (likely(orig_node))
1220 batadv_orig_node_put(orig_node);
1221 if (likely(primary_if))
1222 batadv_hardif_put(primary_if);
1223
1224 return ret;
1225}
1226
1227/**
1228 * batadv_tp_handle_out_of_order - store an out of order packet
1229 * @tp_vars: the private data of the current TP meter session
1230 * @skb: the buffer containing the received packet
1231 *
1232 * Store the out of order packet in the unacked list for late processing. This
1233 * packets are kept in this list so that they can be ACKed at once as soon as
1234 * all the previous packets have been received
1235 *
1236 * Return: true if the packed has been successfully processed, false otherwise
1237 */
1238static bool batadv_tp_handle_out_of_order(struct batadv_tp_vars *tp_vars,
1239 const struct sk_buff *skb)
1240{
1241 const struct batadv_icmp_tp_packet *icmp;
1242 struct batadv_tp_unacked *un, *new;
1243 u32 payload_len;
1244 bool added = false;
1245
1246 new = kmalloc(sizeof(*new), GFP_ATOMIC);
1247 if (unlikely(!new))
1248 return false;
1249
1250 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1251
1252 new->seqno = ntohl(icmp->seqno);
1253 payload_len = skb->len - sizeof(struct batadv_unicast_packet);
1254 new->len = payload_len;
1255
1256 spin_lock_bh(&tp_vars->unacked_lock);
1257 /* if the list is empty immediately attach this new object */
1258 if (list_empty(&tp_vars->unacked_list)) {
1259 list_add(&new->list, &tp_vars->unacked_list);
1260 goto out;
1261 }
1262
1263 /* otherwise loop over the list and either drop the packet because this
1264 * is a duplicate or store it at the right position.
1265 *
1266 * The iteration is done in the reverse way because it is likely that
1267 * the last received packet (the one being processed now) has a bigger
1268 * seqno than all the others already stored.
1269 */
1270 list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) {
1271 /* check for duplicates */
1272 if (new->seqno == un->seqno) {
1273 if (new->len > un->len)
1274 un->len = new->len;
1275 kfree(new);
1276 added = true;
1277 break;
1278 }
1279
1280 /* look for the right position */
1281 if (batadv_seq_before(new->seqno, un->seqno))
1282 continue;
1283
1284 /* as soon as an entry having a bigger seqno is found, the new
1285 * one is attached _after_ it. In this way the list is kept in
1286 * ascending order
1287 */
1288 list_add_tail(&new->list, &un->list);
1289 added = true;
1290 break;
1291 }
1292
1293 /* received packet with smallest seqno out of order; add it to front */
1294 if (!added)
1295 list_add(&new->list, &tp_vars->unacked_list);
1296
1297out:
1298 spin_unlock_bh(&tp_vars->unacked_lock);
1299
1300 return true;
1301}
1302
1303/**
1304 * batadv_tp_ack_unordered - update number received bytes in current stream
1305 * without gaps
1306 * @tp_vars: the private data of the current TP meter session
1307 */
1308static void batadv_tp_ack_unordered(struct batadv_tp_vars *tp_vars)
1309{
1310 struct batadv_tp_unacked *un, *safe;
1311 u32 to_ack;
1312
1313 /* go through the unacked packet list and possibly ACK them as
1314 * well
1315 */
1316 spin_lock_bh(&tp_vars->unacked_lock);
1317 list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
1318 /* the list is ordered, therefore it is possible to stop as soon
1319 * there is a gap between the last acked seqno and the seqno of
1320 * the packet under inspection
1321 */
1322 if (batadv_seq_before(tp_vars->last_recv, un->seqno))
1323 break;
1324
1325 to_ack = un->seqno + un->len - tp_vars->last_recv;
1326
1327 if (batadv_seq_before(tp_vars->last_recv, un->seqno + un->len))
1328 tp_vars->last_recv += to_ack;
1329
1330 list_del(&un->list);
1331 kfree(un);
1332 }
1333 spin_unlock_bh(&tp_vars->unacked_lock);
1334}
1335
1336/**
1337 * batadv_tp_init_recv - return matching or create new receiver tp_vars
1338 * @bat_priv: the bat priv with all the soft interface information
1339 * @icmp: received icmp tp msg
1340 *
1341 * Return: corresponding tp_vars or NULL on errors
1342 */
1343static struct batadv_tp_vars *
1344batadv_tp_init_recv(struct batadv_priv *bat_priv,
1345 const struct batadv_icmp_tp_packet *icmp)
1346{
1347 struct batadv_tp_vars *tp_vars;
1348
1349 spin_lock_bh(&bat_priv->tp_list_lock);
1350 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
1351 icmp->session);
1352 if (tp_vars)
1353 goto out_unlock;
1354
1355 if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
1356 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1357 "Meter: too many ongoing sessions, aborting (RECV)\n");
1358 goto out_unlock;
1359 }
1360
1361 tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
1362 if (!tp_vars)
1363 goto out_unlock;
1364
1365 ether_addr_copy(tp_vars->other_end, icmp->orig);
1366 tp_vars->role = BATADV_TP_RECEIVER;
1367 memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session));
1368 tp_vars->last_recv = BATADV_TP_FIRST_SEQ;
1369 tp_vars->bat_priv = bat_priv;
1370 kref_init(&tp_vars->refcount);
1371
1372 spin_lock_init(&tp_vars->unacked_lock);
1373 INIT_LIST_HEAD(&tp_vars->unacked_list);
1374
1375 kref_get(&tp_vars->refcount);
1376 hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
1377
1378 kref_get(&tp_vars->refcount);
1379 setup_timer(&tp_vars->timer, batadv_tp_receiver_shutdown,
1380 (unsigned long)tp_vars);
1381
1382 batadv_tp_reset_receiver_timer(tp_vars);
1383
1384out_unlock:
1385 spin_unlock_bh(&bat_priv->tp_list_lock);
1386
1387 return tp_vars;
1388}
1389
1390/**
1391 * batadv_tp_recv_msg - process a single data message
1392 * @bat_priv: the bat priv with all the soft interface information
1393 * @skb: the buffer containing the received packet
1394 *
1395 * Process a received TP MSG packet
1396 */
1397static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
1398 const struct sk_buff *skb)
1399{
1400 const struct batadv_icmp_tp_packet *icmp;
1401 struct batadv_tp_vars *tp_vars;
1402 size_t packet_size;
1403 u32 seqno;
1404
1405 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1406
1407 seqno = ntohl(icmp->seqno);
1408 /* check if this is the first seqno. This means that if the
1409 * first packet is lost, the tp meter does not work anymore!
1410 */
1411 if (seqno == BATADV_TP_FIRST_SEQ) {
1412 tp_vars = batadv_tp_init_recv(bat_priv, icmp);
1413 if (!tp_vars) {
1414 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1415 "Meter: seqno != BATADV_TP_FIRST_SEQ cannot initiate connection\n");
1416 goto out;
1417 }
1418 } else {
1419 tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
1420 icmp->session);
1421 if (!tp_vars) {
1422 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1423 "Unexpected packet from %pM!\n",
1424 icmp->orig);
1425 goto out;
1426 }
1427 }
1428
1429 if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) {
1430 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1431 "Meter: dropping packet: not expected (role=%u)\n",
1432 tp_vars->role);
1433 goto out;
1434 }
1435
1436 tp_vars->last_recv_time = jiffies;
1437
1438 /* if the packet is a duplicate, it may be the case that an ACK has been
1439 * lost. Resend the ACK
1440 */
1441 if (batadv_seq_before(seqno, tp_vars->last_recv))
1442 goto send_ack;
1443
1444 /* if the packet is out of order enqueue it */
1445 if (ntohl(icmp->seqno) != tp_vars->last_recv) {
1446 /* exit immediately (and do not send any ACK) if the packet has
1447 * not been enqueued correctly
1448 */
1449 if (!batadv_tp_handle_out_of_order(tp_vars, skb))
1450 goto out;
1451
1452 /* send a duplicate ACK */
1453 goto send_ack;
1454 }
1455
1456 /* if everything was fine count the ACKed bytes */
1457 packet_size = skb->len - sizeof(struct batadv_unicast_packet);
1458 tp_vars->last_recv += packet_size;
1459
1460 /* check if this ordered message filled a gap.... */
1461 batadv_tp_ack_unordered(tp_vars);
1462
1463send_ack:
1464 /* send the ACK. If the received packet was out of order, the ACK that
1465 * is going to be sent is a duplicate (the sender will count them and
1466 * possibly enter Fast Retransmit as soon as it has reached 3)
1467 */
1468 batadv_tp_send_ack(bat_priv, icmp->orig, tp_vars->last_recv,
1469 icmp->timestamp, icmp->session, icmp->uid);
1470out:
1471 if (likely(tp_vars))
1472 batadv_tp_vars_put(tp_vars);
1473}
1474
1475/**
1476 * batadv_tp_meter_recv - main TP Meter receiving function
1477 * @bat_priv: the bat priv with all the soft interface information
1478 * @skb: the buffer containing the received packet
1479 */
1480void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb)
1481{
1482 struct batadv_icmp_tp_packet *icmp;
1483
1484 icmp = (struct batadv_icmp_tp_packet *)skb->data;
1485
1486 switch (icmp->subtype) {
1487 case BATADV_TP_MSG:
1488 batadv_tp_recv_msg(bat_priv, skb);
1489 break;
1490 case BATADV_TP_ACK:
1491 batadv_tp_recv_ack(bat_priv, skb);
1492 break;
1493 default:
1494 batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
1495 "Received unknown TP Metric packet type %u\n",
1496 icmp->subtype);
1497 }
1498 consume_skb(skb);
1499}
1500
1501/**
1502 * batadv_tp_meter_init - initialize global tp_meter structures
1503 */
1504void batadv_tp_meter_init(void)
1505{
1506 get_random_bytes(batadv_tp_prerandom, sizeof(batadv_tp_prerandom));
1507}