xref: /openbmc/linux/net/can/j1939/transport.c (revision 99a15348)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2010-2011 EIA Electronics,
3 //                         Kurt Van Dijck <kurt.van.dijck@eia.be>
4 // Copyright (c) 2018 Protonic,
5 //                         Robin van der Gracht <robin@protonic.nl>
6 // Copyright (c) 2017-2019 Pengutronix,
7 //                         Marc Kleine-Budde <kernel@pengutronix.de>
8 // Copyright (c) 2017-2019 Pengutronix,
9 //                         Oleksij Rempel <kernel@pengutronix.de>
10 
11 #include <linux/can/skb.h>
12 
13 #include "j1939-priv.h"
14 
15 #define J1939_XTP_TX_RETRY_LIMIT 100
16 
17 #define J1939_ETP_PGN_CTL 0xc800
18 #define J1939_ETP_PGN_DAT 0xc700
19 #define J1939_TP_PGN_CTL 0xec00
20 #define J1939_TP_PGN_DAT 0xeb00
21 
22 #define J1939_TP_CMD_RTS 0x10
23 #define J1939_TP_CMD_CTS 0x11
24 #define J1939_TP_CMD_EOMA 0x13
25 #define J1939_TP_CMD_BAM 0x20
26 #define J1939_TP_CMD_ABORT 0xff
27 
28 #define J1939_ETP_CMD_RTS 0x14
29 #define J1939_ETP_CMD_CTS 0x15
30 #define J1939_ETP_CMD_DPO 0x16
31 #define J1939_ETP_CMD_EOMA 0x17
32 #define J1939_ETP_CMD_ABORT 0xff
33 
34 enum j1939_xtp_abort {
35 	J1939_XTP_NO_ABORT = 0,
36 	J1939_XTP_ABORT_BUSY = 1,
37 	/* Already in one or more connection managed sessions and
38 	 * cannot support another.
39 	 *
40 	 * EALREADY:
41 	 * Operation already in progress
42 	 */
43 
44 	J1939_XTP_ABORT_RESOURCE = 2,
45 	/* System resources were needed for another task so this
46 	 * connection managed session was terminated.
47 	 *
48 	 * EMSGSIZE:
49 	 * The socket type requires that message be sent atomically,
50 	 * and the size of the message to be sent made this
51 	 * impossible.
52 	 */
53 
54 	J1939_XTP_ABORT_TIMEOUT = 3,
55 	/* A timeout occurred and this is the connection abort to
56 	 * close the session.
57 	 *
58 	 * EHOSTUNREACH:
59 	 * The destination host cannot be reached (probably because
60 	 * the host is down or a remote router cannot reach it).
61 	 */
62 
63 	J1939_XTP_ABORT_GENERIC = 4,
64 	/* CTS messages received when data transfer is in progress
65 	 *
66 	 * EBADMSG:
67 	 * Not a data message
68 	 */
69 
70 	J1939_XTP_ABORT_FAULT = 5,
71 	/* Maximal retransmit request limit reached
72 	 *
73 	 * ENOTRECOVERABLE:
74 	 * State not recoverable
75 	 */
76 
77 	J1939_XTP_ABORT_UNEXPECTED_DATA = 6,
78 	/* Unexpected data transfer packet
79 	 *
80 	 * ENOTCONN:
81 	 * Transport endpoint is not connected
82 	 */
83 
84 	J1939_XTP_ABORT_BAD_SEQ = 7,
85 	/* Bad sequence number (and software is not able to recover)
86 	 *
87 	 * EILSEQ:
88 	 * Illegal byte sequence
89 	 */
90 
91 	J1939_XTP_ABORT_DUP_SEQ = 8,
92 	/* Duplicate sequence number (and software is not able to
93 	 * recover)
94 	 */
95 
96 	J1939_XTP_ABORT_EDPO_UNEXPECTED = 9,
97 	/* Unexpected EDPO packet (ETP) or Message size > 1785 bytes
98 	 * (TP)
99 	 */
100 
101 	J1939_XTP_ABORT_BAD_EDPO_PGN = 10,
102 	/* Unexpected EDPO PGN (PGN in EDPO is bad) */
103 
104 	J1939_XTP_ABORT_EDPO_OUTOF_CTS = 11,
105 	/* EDPO number of packets is greater than CTS */
106 
107 	J1939_XTP_ABORT_BAD_EDPO_OFFSET = 12,
108 	/* Bad EDPO offset */
109 
110 	J1939_XTP_ABORT_OTHER_DEPRECATED = 13,
111 	/* Deprecated. Use 250 instead (Any other reason)  */
112 
113 	J1939_XTP_ABORT_ECTS_UNXPECTED_PGN = 14,
114 	/* Unexpected ECTS PGN (PGN in ECTS is bad) */
115 
116 	J1939_XTP_ABORT_ECTS_TOO_BIG = 15,
117 	/* ECTS requested packets exceeds message size */
118 
119 	J1939_XTP_ABORT_OTHER = 250,
120 	/* Any other reason (if a Connection Abort reason is
121 	 * identified that is not listed in the table use code 250)
122 	 */
123 };
124 
125 static unsigned int j1939_tp_block = 255;
126 static unsigned int j1939_tp_packet_delay;
127 static unsigned int j1939_tp_padding = 1;
128 
129 /* helpers */
130 static const char *j1939_xtp_abort_to_str(enum j1939_xtp_abort abort)
131 {
132 	switch (abort) {
133 	case J1939_XTP_ABORT_BUSY:
134 		return "Already in one or more connection managed sessions and cannot support another.";
135 	case J1939_XTP_ABORT_RESOURCE:
136 		return "System resources were needed for another task so this connection managed session was terminated.";
137 	case J1939_XTP_ABORT_TIMEOUT:
138 		return "A timeout occurred and this is the connection abort to close the session.";
139 	case J1939_XTP_ABORT_GENERIC:
140 		return "CTS messages received when data transfer is in progress";
141 	case J1939_XTP_ABORT_FAULT:
142 		return "Maximal retransmit request limit reached";
143 	case J1939_XTP_ABORT_UNEXPECTED_DATA:
144 		return "Unexpected data transfer packet";
145 	case J1939_XTP_ABORT_BAD_SEQ:
146 		return "Bad sequence number (and software is not able to recover)";
147 	case J1939_XTP_ABORT_DUP_SEQ:
148 		return "Duplicate sequence number (and software is not able to recover)";
149 	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
150 		return "Unexpected EDPO packet (ETP) or Message size > 1785 bytes (TP)";
151 	case J1939_XTP_ABORT_BAD_EDPO_PGN:
152 		return "Unexpected EDPO PGN (PGN in EDPO is bad)";
153 	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
154 		return "EDPO number of packets is greater than CTS";
155 	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
156 		return "Bad EDPO offset";
157 	case J1939_XTP_ABORT_OTHER_DEPRECATED:
158 		return "Deprecated. Use 250 instead (Any other reason)";
159 	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
160 		return "Unexpected ECTS PGN (PGN in ECTS is bad)";
161 	case J1939_XTP_ABORT_ECTS_TOO_BIG:
162 		return "ECTS requested packets exceeds message size";
163 	case J1939_XTP_ABORT_OTHER:
164 		return "Any other reason (if a Connection Abort reason is identified that is not listed in the table use code 250)";
165 	default:
166 		return "<unknown>";
167 	}
168 }
169 
170 static int j1939_xtp_abort_to_errno(struct j1939_priv *priv,
171 				    enum j1939_xtp_abort abort)
172 {
173 	int err;
174 
175 	switch (abort) {
176 	case J1939_XTP_NO_ABORT:
177 		WARN_ON_ONCE(abort == J1939_XTP_NO_ABORT);
178 		err = 0;
179 		break;
180 	case J1939_XTP_ABORT_BUSY:
181 		err = EALREADY;
182 		break;
183 	case J1939_XTP_ABORT_RESOURCE:
184 		err = EMSGSIZE;
185 		break;
186 	case J1939_XTP_ABORT_TIMEOUT:
187 		err = EHOSTUNREACH;
188 		break;
189 	case J1939_XTP_ABORT_GENERIC:
190 		err = EBADMSG;
191 		break;
192 	case J1939_XTP_ABORT_FAULT:
193 		err = ENOTRECOVERABLE;
194 		break;
195 	case J1939_XTP_ABORT_UNEXPECTED_DATA:
196 		err = ENOTCONN;
197 		break;
198 	case J1939_XTP_ABORT_BAD_SEQ:
199 		err = EILSEQ;
200 		break;
201 	case J1939_XTP_ABORT_DUP_SEQ:
202 		err = EPROTO;
203 		break;
204 	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
205 		err = EPROTO;
206 		break;
207 	case J1939_XTP_ABORT_BAD_EDPO_PGN:
208 		err = EPROTO;
209 		break;
210 	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
211 		err = EPROTO;
212 		break;
213 	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
214 		err = EPROTO;
215 		break;
216 	case J1939_XTP_ABORT_OTHER_DEPRECATED:
217 		err = EPROTO;
218 		break;
219 	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
220 		err = EPROTO;
221 		break;
222 	case J1939_XTP_ABORT_ECTS_TOO_BIG:
223 		err = EPROTO;
224 		break;
225 	case J1939_XTP_ABORT_OTHER:
226 		err = EPROTO;
227 		break;
228 	default:
229 		netdev_warn(priv->ndev, "Unknown abort code %i", abort);
230 		err = EPROTO;
231 	}
232 
233 	return err;
234 }
235 
236 static inline void j1939_session_list_lock(struct j1939_priv *priv)
237 {
238 	spin_lock_bh(&priv->active_session_list_lock);
239 }
240 
241 static inline void j1939_session_list_unlock(struct j1939_priv *priv)
242 {
243 	spin_unlock_bh(&priv->active_session_list_lock);
244 }
245 
246 void j1939_session_get(struct j1939_session *session)
247 {
248 	kref_get(&session->kref);
249 }
250 
251 /* session completion functions */
252 static void __j1939_session_drop(struct j1939_session *session)
253 {
254 	if (!session->transmission)
255 		return;
256 
257 	j1939_sock_pending_del(session->sk);
258 	sock_put(session->sk);
259 }
260 
261 static void j1939_session_destroy(struct j1939_session *session)
262 {
263 	if (session->transmission) {
264 		if (session->err)
265 			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ABORT);
266 		else
267 			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ACK);
268 	} else if (session->err) {
269 			j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
270 	}
271 
272 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
273 
274 	WARN_ON_ONCE(!list_empty(&session->sk_session_queue_entry));
275 	WARN_ON_ONCE(!list_empty(&session->active_session_list_entry));
276 
277 	skb_queue_purge(&session->skb_queue);
278 	__j1939_session_drop(session);
279 	j1939_priv_put(session->priv);
280 	kfree(session);
281 }
282 
283 static void __j1939_session_release(struct kref *kref)
284 {
285 	struct j1939_session *session = container_of(kref, struct j1939_session,
286 						     kref);
287 
288 	j1939_session_destroy(session);
289 }
290 
291 void j1939_session_put(struct j1939_session *session)
292 {
293 	kref_put(&session->kref, __j1939_session_release);
294 }
295 
296 static void j1939_session_txtimer_cancel(struct j1939_session *session)
297 {
298 	if (hrtimer_cancel(&session->txtimer))
299 		j1939_session_put(session);
300 }
301 
302 static void j1939_session_rxtimer_cancel(struct j1939_session *session)
303 {
304 	if (hrtimer_cancel(&session->rxtimer))
305 		j1939_session_put(session);
306 }
307 
308 void j1939_session_timers_cancel(struct j1939_session *session)
309 {
310 	j1939_session_txtimer_cancel(session);
311 	j1939_session_rxtimer_cancel(session);
312 }
313 
314 static inline bool j1939_cb_is_broadcast(const struct j1939_sk_buff_cb *skcb)
315 {
316 	return (!skcb->addr.dst_name && (skcb->addr.da == 0xff));
317 }
318 
319 static void j1939_session_skb_drop_old(struct j1939_session *session)
320 {
321 	struct sk_buff *do_skb;
322 	struct j1939_sk_buff_cb *do_skcb;
323 	unsigned int offset_start;
324 	unsigned long flags;
325 
326 	if (skb_queue_len(&session->skb_queue) < 2)
327 		return;
328 
329 	offset_start = session->pkt.tx_acked * 7;
330 
331 	spin_lock_irqsave(&session->skb_queue.lock, flags);
332 	do_skb = skb_peek(&session->skb_queue);
333 	do_skcb = j1939_skb_to_cb(do_skb);
334 
335 	if ((do_skcb->offset + do_skb->len) < offset_start) {
336 		__skb_unlink(do_skb, &session->skb_queue);
337 		/* drop ref taken in j1939_session_skb_queue() */
338 		skb_unref(do_skb);
339 
340 		kfree_skb(do_skb);
341 	}
342 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
343 }
344 
345 void j1939_session_skb_queue(struct j1939_session *session,
346 			     struct sk_buff *skb)
347 {
348 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
349 	struct j1939_priv *priv = session->priv;
350 
351 	j1939_ac_fixup(priv, skb);
352 
353 	if (j1939_address_is_unicast(skcb->addr.da) &&
354 	    priv->ents[skcb->addr.da].nusers)
355 		skcb->flags |= J1939_ECU_LOCAL_DST;
356 
357 	skcb->flags |= J1939_ECU_LOCAL_SRC;
358 
359 	skb_get(skb);
360 	skb_queue_tail(&session->skb_queue, skb);
361 }
362 
363 static struct
364 sk_buff *j1939_session_skb_get_by_offset(struct j1939_session *session,
365 					 unsigned int offset_start)
366 {
367 	struct j1939_priv *priv = session->priv;
368 	struct j1939_sk_buff_cb *do_skcb;
369 	struct sk_buff *skb = NULL;
370 	struct sk_buff *do_skb;
371 	unsigned long flags;
372 
373 	spin_lock_irqsave(&session->skb_queue.lock, flags);
374 	skb_queue_walk(&session->skb_queue, do_skb) {
375 		do_skcb = j1939_skb_to_cb(do_skb);
376 
377 		if (offset_start >= do_skcb->offset &&
378 		    offset_start < (do_skcb->offset + do_skb->len)) {
379 			skb = do_skb;
380 		}
381 	}
382 
383 	if (skb)
384 		skb_get(skb);
385 
386 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
387 
388 	if (!skb)
389 		netdev_dbg(priv->ndev, "%s: 0x%p: no skb found for start: %i, queue size: %i\n",
390 			   __func__, session, offset_start,
391 			   skb_queue_len(&session->skb_queue));
392 
393 	return skb;
394 }
395 
396 static struct sk_buff *j1939_session_skb_get(struct j1939_session *session)
397 {
398 	unsigned int offset_start;
399 
400 	offset_start = session->pkt.dpo * 7;
401 	return j1939_session_skb_get_by_offset(session, offset_start);
402 }
403 
404 /* see if we are receiver
405  * returns 0 for broadcasts, although we will receive them
406  */
407 static inline int j1939_tp_im_receiver(const struct j1939_sk_buff_cb *skcb)
408 {
409 	return skcb->flags & J1939_ECU_LOCAL_DST;
410 }
411 
412 /* see if we are sender */
413 static inline int j1939_tp_im_transmitter(const struct j1939_sk_buff_cb *skcb)
414 {
415 	return skcb->flags & J1939_ECU_LOCAL_SRC;
416 }
417 
418 /* see if we are involved as either receiver or transmitter */
419 static int j1939_tp_im_involved(const struct j1939_sk_buff_cb *skcb, bool swap)
420 {
421 	if (swap)
422 		return j1939_tp_im_receiver(skcb);
423 	else
424 		return j1939_tp_im_transmitter(skcb);
425 }
426 
427 static int j1939_tp_im_involved_anydir(struct j1939_sk_buff_cb *skcb)
428 {
429 	return skcb->flags & (J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
430 }
431 
432 /* extract pgn from flow-ctl message */
433 static inline pgn_t j1939_xtp_ctl_to_pgn(const u8 *dat)
434 {
435 	pgn_t pgn;
436 
437 	pgn = (dat[7] << 16) | (dat[6] << 8) | (dat[5] << 0);
438 	if (j1939_pgn_is_pdu1(pgn))
439 		pgn &= 0xffff00;
440 	return pgn;
441 }
442 
443 static inline unsigned int j1939_tp_ctl_to_size(const u8 *dat)
444 {
445 	return (dat[2] << 8) + (dat[1] << 0);
446 }
447 
448 static inline unsigned int j1939_etp_ctl_to_packet(const u8 *dat)
449 {
450 	return (dat[4] << 16) | (dat[3] << 8) | (dat[2] << 0);
451 }
452 
453 static inline unsigned int j1939_etp_ctl_to_size(const u8 *dat)
454 {
455 	return (dat[4] << 24) | (dat[3] << 16) |
456 		(dat[2] << 8) | (dat[1] << 0);
457 }
458 
459 /* find existing session:
460  * reverse: swap cb's src & dst
461  * there is no problem with matching broadcasts, since
462  * broadcasts (no dst, no da) would never call this
463  * with reverse == true
464  */
465 static bool j1939_session_match(struct j1939_addr *se_addr,
466 				struct j1939_addr *sk_addr, bool reverse)
467 {
468 	if (se_addr->type != sk_addr->type)
469 		return false;
470 
471 	if (reverse) {
472 		if (se_addr->src_name) {
473 			if (se_addr->src_name != sk_addr->dst_name)
474 				return false;
475 		} else if (se_addr->sa != sk_addr->da) {
476 			return false;
477 		}
478 
479 		if (se_addr->dst_name) {
480 			if (se_addr->dst_name != sk_addr->src_name)
481 				return false;
482 		} else if (se_addr->da != sk_addr->sa) {
483 			return false;
484 		}
485 	} else {
486 		if (se_addr->src_name) {
487 			if (se_addr->src_name != sk_addr->src_name)
488 				return false;
489 		} else if (se_addr->sa != sk_addr->sa) {
490 			return false;
491 		}
492 
493 		if (se_addr->dst_name) {
494 			if (se_addr->dst_name != sk_addr->dst_name)
495 				return false;
496 		} else if (se_addr->da != sk_addr->da) {
497 			return false;
498 		}
499 	}
500 
501 	return true;
502 }
503 
504 static struct
505 j1939_session *j1939_session_get_by_addr_locked(struct j1939_priv *priv,
506 						struct list_head *root,
507 						struct j1939_addr *addr,
508 						bool reverse, bool transmitter)
509 {
510 	struct j1939_session *session;
511 
512 	lockdep_assert_held(&priv->active_session_list_lock);
513 
514 	list_for_each_entry(session, root, active_session_list_entry) {
515 		j1939_session_get(session);
516 		if (j1939_session_match(&session->skcb.addr, addr, reverse) &&
517 		    session->transmission == transmitter)
518 			return session;
519 		j1939_session_put(session);
520 	}
521 
522 	return NULL;
523 }
524 
525 static struct
526 j1939_session *j1939_session_get_simple(struct j1939_priv *priv,
527 					struct sk_buff *skb)
528 {
529 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
530 	struct j1939_session *session;
531 
532 	lockdep_assert_held(&priv->active_session_list_lock);
533 
534 	list_for_each_entry(session, &priv->active_session_list,
535 			    active_session_list_entry) {
536 		j1939_session_get(session);
537 		if (session->skcb.addr.type == J1939_SIMPLE &&
538 		    session->tskey == skcb->tskey && session->sk == skb->sk)
539 			return session;
540 		j1939_session_put(session);
541 	}
542 
543 	return NULL;
544 }
545 
546 static struct
547 j1939_session *j1939_session_get_by_addr(struct j1939_priv *priv,
548 					 struct j1939_addr *addr,
549 					 bool reverse, bool transmitter)
550 {
551 	struct j1939_session *session;
552 
553 	j1939_session_list_lock(priv);
554 	session = j1939_session_get_by_addr_locked(priv,
555 						   &priv->active_session_list,
556 						   addr, reverse, transmitter);
557 	j1939_session_list_unlock(priv);
558 
559 	return session;
560 }
561 
562 static void j1939_skbcb_swap(struct j1939_sk_buff_cb *skcb)
563 {
564 	u8 tmp = 0;
565 
566 	swap(skcb->addr.dst_name, skcb->addr.src_name);
567 	swap(skcb->addr.da, skcb->addr.sa);
568 
569 	/* swap SRC and DST flags, leave other untouched */
570 	if (skcb->flags & J1939_ECU_LOCAL_SRC)
571 		tmp |= J1939_ECU_LOCAL_DST;
572 	if (skcb->flags & J1939_ECU_LOCAL_DST)
573 		tmp |= J1939_ECU_LOCAL_SRC;
574 	skcb->flags &= ~(J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
575 	skcb->flags |= tmp;
576 }
577 
578 static struct
579 sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv,
580 			     const struct j1939_sk_buff_cb *re_skcb,
581 			     bool ctl,
582 			     bool swap_src_dst)
583 {
584 	struct sk_buff *skb;
585 	struct j1939_sk_buff_cb *skcb;
586 
587 	skb = alloc_skb(sizeof(struct can_frame) + sizeof(struct can_skb_priv),
588 			GFP_ATOMIC);
589 	if (unlikely(!skb))
590 		return ERR_PTR(-ENOMEM);
591 
592 	skb->dev = priv->ndev;
593 	can_skb_reserve(skb);
594 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
595 	can_skb_prv(skb)->skbcnt = 0;
596 	/* reserve CAN header */
597 	skb_reserve(skb, offsetof(struct can_frame, data));
598 
599 	memcpy(skb->cb, re_skcb, sizeof(skb->cb));
600 	skcb = j1939_skb_to_cb(skb);
601 	if (swap_src_dst)
602 		j1939_skbcb_swap(skcb);
603 
604 	if (ctl) {
605 		if (skcb->addr.type == J1939_ETP)
606 			skcb->addr.pgn = J1939_ETP_PGN_CTL;
607 		else
608 			skcb->addr.pgn = J1939_TP_PGN_CTL;
609 	} else {
610 		if (skcb->addr.type == J1939_ETP)
611 			skcb->addr.pgn = J1939_ETP_PGN_DAT;
612 		else
613 			skcb->addr.pgn = J1939_TP_PGN_DAT;
614 	}
615 
616 	return skb;
617 }
618 
619 /* TP transmit packet functions */
620 static int j1939_tp_tx_dat(struct j1939_session *session,
621 			   const u8 *dat, int len)
622 {
623 	struct j1939_priv *priv = session->priv;
624 	struct sk_buff *skb;
625 
626 	skb = j1939_tp_tx_dat_new(priv, &session->skcb,
627 				  false, false);
628 	if (IS_ERR(skb))
629 		return PTR_ERR(skb);
630 
631 	skb_put_data(skb, dat, len);
632 	if (j1939_tp_padding && len < 8)
633 		memset(skb_put(skb, 8 - len), 0xff, 8 - len);
634 
635 	return j1939_send_one(priv, skb);
636 }
637 
638 static int j1939_xtp_do_tx_ctl(struct j1939_priv *priv,
639 			       const struct j1939_sk_buff_cb *re_skcb,
640 			       bool swap_src_dst, pgn_t pgn, const u8 *dat)
641 {
642 	struct sk_buff *skb;
643 	u8 *skdat;
644 
645 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
646 		return 0;
647 
648 	skb = j1939_tp_tx_dat_new(priv, re_skcb, true, swap_src_dst);
649 	if (IS_ERR(skb))
650 		return PTR_ERR(skb);
651 
652 	skdat = skb_put(skb, 8);
653 	memcpy(skdat, dat, 5);
654 	skdat[5] = (pgn >> 0);
655 	skdat[6] = (pgn >> 8);
656 	skdat[7] = (pgn >> 16);
657 
658 	return j1939_send_one(priv, skb);
659 }
660 
661 static inline int j1939_tp_tx_ctl(struct j1939_session *session,
662 				  bool swap_src_dst, const u8 *dat)
663 {
664 	struct j1939_priv *priv = session->priv;
665 
666 	return j1939_xtp_do_tx_ctl(priv, &session->skcb,
667 				   swap_src_dst,
668 				   session->skcb.addr.pgn, dat);
669 }
670 
671 static int j1939_xtp_tx_abort(struct j1939_priv *priv,
672 			      const struct j1939_sk_buff_cb *re_skcb,
673 			      bool swap_src_dst,
674 			      enum j1939_xtp_abort err,
675 			      pgn_t pgn)
676 {
677 	u8 dat[5];
678 
679 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
680 		return 0;
681 
682 	memset(dat, 0xff, sizeof(dat));
683 	dat[0] = J1939_TP_CMD_ABORT;
684 	dat[1] = err;
685 	return j1939_xtp_do_tx_ctl(priv, re_skcb, swap_src_dst, pgn, dat);
686 }
687 
688 void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec)
689 {
690 	j1939_session_get(session);
691 	hrtimer_start(&session->txtimer, ms_to_ktime(msec),
692 		      HRTIMER_MODE_REL_SOFT);
693 }
694 
695 static inline void j1939_tp_set_rxtimeout(struct j1939_session *session,
696 					  int msec)
697 {
698 	j1939_session_rxtimer_cancel(session);
699 	j1939_session_get(session);
700 	hrtimer_start(&session->rxtimer, ms_to_ktime(msec),
701 		      HRTIMER_MODE_REL_SOFT);
702 }
703 
704 static int j1939_session_tx_rts(struct j1939_session *session)
705 {
706 	u8 dat[8];
707 	int ret;
708 
709 	memset(dat, 0xff, sizeof(dat));
710 
711 	dat[1] = (session->total_message_size >> 0);
712 	dat[2] = (session->total_message_size >> 8);
713 	dat[3] = session->pkt.total;
714 
715 	if (session->skcb.addr.type == J1939_ETP) {
716 		dat[0] = J1939_ETP_CMD_RTS;
717 		dat[1] = (session->total_message_size >> 0);
718 		dat[2] = (session->total_message_size >> 8);
719 		dat[3] = (session->total_message_size >> 16);
720 		dat[4] = (session->total_message_size >> 24);
721 	} else if (j1939_cb_is_broadcast(&session->skcb)) {
722 		dat[0] = J1939_TP_CMD_BAM;
723 		/* fake cts for broadcast */
724 		session->pkt.tx = 0;
725 	} else {
726 		dat[0] = J1939_TP_CMD_RTS;
727 		dat[4] = dat[3];
728 	}
729 
730 	if (dat[0] == session->last_txcmd)
731 		/* done already */
732 		return 0;
733 
734 	ret = j1939_tp_tx_ctl(session, false, dat);
735 	if (ret < 0)
736 		return ret;
737 
738 	session->last_txcmd = dat[0];
739 	if (dat[0] == J1939_TP_CMD_BAM) {
740 		j1939_tp_schedule_txtimer(session, 50);
741 		j1939_tp_set_rxtimeout(session, 250);
742 	} else {
743 		j1939_tp_set_rxtimeout(session, 1250);
744 	}
745 
746 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
747 
748 	return 0;
749 }
750 
751 static int j1939_session_tx_dpo(struct j1939_session *session)
752 {
753 	unsigned int pkt;
754 	u8 dat[8];
755 	int ret;
756 
757 	memset(dat, 0xff, sizeof(dat));
758 
759 	dat[0] = J1939_ETP_CMD_DPO;
760 	session->pkt.dpo = session->pkt.tx_acked;
761 	pkt = session->pkt.dpo;
762 	dat[1] = session->pkt.last - session->pkt.tx_acked;
763 	dat[2] = (pkt >> 0);
764 	dat[3] = (pkt >> 8);
765 	dat[4] = (pkt >> 16);
766 
767 	ret = j1939_tp_tx_ctl(session, false, dat);
768 	if (ret < 0)
769 		return ret;
770 
771 	session->last_txcmd = dat[0];
772 	j1939_tp_set_rxtimeout(session, 1250);
773 	session->pkt.tx = session->pkt.tx_acked;
774 
775 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
776 
777 	return 0;
778 }
779 
780 static int j1939_session_tx_dat(struct j1939_session *session)
781 {
782 	struct j1939_priv *priv = session->priv;
783 	struct j1939_sk_buff_cb *se_skcb;
784 	int offset, pkt_done, pkt_end;
785 	unsigned int len, pdelay;
786 	struct sk_buff *se_skb;
787 	const u8 *tpdat;
788 	int ret = 0;
789 	u8 dat[8];
790 
791 	se_skb = j1939_session_skb_get_by_offset(session, session->pkt.tx * 7);
792 	if (!se_skb)
793 		return -ENOBUFS;
794 
795 	se_skcb = j1939_skb_to_cb(se_skb);
796 	tpdat = se_skb->data;
797 	ret = 0;
798 	pkt_done = 0;
799 	if (session->skcb.addr.type != J1939_ETP &&
800 	    j1939_cb_is_broadcast(&session->skcb))
801 		pkt_end = session->pkt.total;
802 	else
803 		pkt_end = session->pkt.last;
804 
805 	while (session->pkt.tx < pkt_end) {
806 		dat[0] = session->pkt.tx - session->pkt.dpo + 1;
807 		offset = (session->pkt.tx * 7) - se_skcb->offset;
808 		len =  se_skb->len - offset;
809 		if (len > 7)
810 			len = 7;
811 
812 		if (offset + len > se_skb->len) {
813 			netdev_err_once(priv->ndev,
814 					"%s: 0x%p: requested data outside of queued buffer: offset %i, len %i, pkt.tx: %i\n",
815 					__func__, session, se_skcb->offset,
816 					se_skb->len , session->pkt.tx);
817 			ret = -EOVERFLOW;
818 			goto out_free;
819 		}
820 
821 		if (!len) {
822 			ret = -ENOBUFS;
823 			break;
824 		}
825 
826 		memcpy(&dat[1], &tpdat[offset], len);
827 		ret = j1939_tp_tx_dat(session, dat, len + 1);
828 		if (ret < 0) {
829 			/* ENOBUFS == CAN interface TX queue is full */
830 			if (ret != -ENOBUFS)
831 				netdev_alert(priv->ndev,
832 					     "%s: 0x%p: queue data error: %i\n",
833 					     __func__, session, ret);
834 			break;
835 		}
836 
837 		session->last_txcmd = 0xff;
838 		pkt_done++;
839 		session->pkt.tx++;
840 		pdelay = j1939_cb_is_broadcast(&session->skcb) ? 50 :
841 			j1939_tp_packet_delay;
842 
843 		if (session->pkt.tx < session->pkt.total && pdelay) {
844 			j1939_tp_schedule_txtimer(session, pdelay);
845 			break;
846 		}
847 	}
848 
849 	if (pkt_done)
850 		j1939_tp_set_rxtimeout(session, 250);
851 
852  out_free:
853 	if (ret)
854 		kfree_skb(se_skb);
855 	else
856 		consume_skb(se_skb);
857 
858 	return ret;
859 }
860 
861 static int j1939_xtp_txnext_transmiter(struct j1939_session *session)
862 {
863 	struct j1939_priv *priv = session->priv;
864 	int ret = 0;
865 
866 	if (!j1939_tp_im_transmitter(&session->skcb)) {
867 		netdev_alert(priv->ndev, "%s: 0x%p: called by not transmitter!\n",
868 			     __func__, session);
869 		return -EINVAL;
870 	}
871 
872 	switch (session->last_cmd) {
873 	case 0:
874 		ret = j1939_session_tx_rts(session);
875 		break;
876 
877 	case J1939_ETP_CMD_CTS:
878 		if (session->last_txcmd != J1939_ETP_CMD_DPO) {
879 			ret = j1939_session_tx_dpo(session);
880 			if (ret)
881 				return ret;
882 		}
883 
884 		fallthrough;
885 	case J1939_TP_CMD_CTS:
886 	case 0xff: /* did some data */
887 	case J1939_ETP_CMD_DPO:
888 	case J1939_TP_CMD_BAM:
889 		ret = j1939_session_tx_dat(session);
890 
891 		break;
892 	default:
893 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
894 			     __func__, session, session->last_cmd);
895 	}
896 
897 	return ret;
898 }
899 
900 static int j1939_session_tx_cts(struct j1939_session *session)
901 {
902 	struct j1939_priv *priv = session->priv;
903 	unsigned int pkt, len;
904 	int ret;
905 	u8 dat[8];
906 
907 	if (!j1939_sk_recv_match(priv, &session->skcb))
908 		return -ENOENT;
909 
910 	len = session->pkt.total - session->pkt.rx;
911 	len = min3(len, session->pkt.block, j1939_tp_block ?: 255);
912 	memset(dat, 0xff, sizeof(dat));
913 
914 	if (session->skcb.addr.type == J1939_ETP) {
915 		pkt = session->pkt.rx + 1;
916 		dat[0] = J1939_ETP_CMD_CTS;
917 		dat[1] = len;
918 		dat[2] = (pkt >> 0);
919 		dat[3] = (pkt >> 8);
920 		dat[4] = (pkt >> 16);
921 	} else {
922 		dat[0] = J1939_TP_CMD_CTS;
923 		dat[1] = len;
924 		dat[2] = session->pkt.rx + 1;
925 	}
926 
927 	if (dat[0] == session->last_txcmd)
928 		/* done already */
929 		return 0;
930 
931 	ret = j1939_tp_tx_ctl(session, true, dat);
932 	if (ret < 0)
933 		return ret;
934 
935 	if (len)
936 		/* only mark cts done when len is set */
937 		session->last_txcmd = dat[0];
938 	j1939_tp_set_rxtimeout(session, 1250);
939 
940 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
941 
942 	return 0;
943 }
944 
945 static int j1939_session_tx_eoma(struct j1939_session *session)
946 {
947 	struct j1939_priv *priv = session->priv;
948 	u8 dat[8];
949 	int ret;
950 
951 	if (!j1939_sk_recv_match(priv, &session->skcb))
952 		return -ENOENT;
953 
954 	memset(dat, 0xff, sizeof(dat));
955 
956 	if (session->skcb.addr.type == J1939_ETP) {
957 		dat[0] = J1939_ETP_CMD_EOMA;
958 		dat[1] = session->total_message_size >> 0;
959 		dat[2] = session->total_message_size >> 8;
960 		dat[3] = session->total_message_size >> 16;
961 		dat[4] = session->total_message_size >> 24;
962 	} else {
963 		dat[0] = J1939_TP_CMD_EOMA;
964 		dat[1] = session->total_message_size;
965 		dat[2] = session->total_message_size >> 8;
966 		dat[3] = session->pkt.total;
967 	}
968 
969 	if (dat[0] == session->last_txcmd)
970 		/* done already */
971 		return 0;
972 
973 	ret = j1939_tp_tx_ctl(session, true, dat);
974 	if (ret < 0)
975 		return ret;
976 
977 	session->last_txcmd = dat[0];
978 
979 	/* wait for the EOMA packet to come in */
980 	j1939_tp_set_rxtimeout(session, 1250);
981 
982 	netdev_dbg(session->priv->ndev, "%p: 0x%p\n", __func__, session);
983 
984 	return 0;
985 }
986 
987 static int j1939_xtp_txnext_receiver(struct j1939_session *session)
988 {
989 	struct j1939_priv *priv = session->priv;
990 	int ret = 0;
991 
992 	if (!j1939_tp_im_receiver(&session->skcb)) {
993 		netdev_alert(priv->ndev, "%s: 0x%p: called by not receiver!\n",
994 			     __func__, session);
995 		return -EINVAL;
996 	}
997 
998 	switch (session->last_cmd) {
999 	case J1939_TP_CMD_RTS:
1000 	case J1939_ETP_CMD_RTS:
1001 		ret = j1939_session_tx_cts(session);
1002 		break;
1003 
1004 	case J1939_ETP_CMD_CTS:
1005 	case J1939_TP_CMD_CTS:
1006 	case 0xff: /* did some data */
1007 	case J1939_ETP_CMD_DPO:
1008 		if ((session->skcb.addr.type == J1939_TP &&
1009 		     j1939_cb_is_broadcast(&session->skcb)))
1010 			break;
1011 
1012 		if (session->pkt.rx >= session->pkt.total) {
1013 			ret = j1939_session_tx_eoma(session);
1014 		} else if (session->pkt.rx >= session->pkt.last) {
1015 			session->last_txcmd = 0;
1016 			ret = j1939_session_tx_cts(session);
1017 		}
1018 		break;
1019 	default:
1020 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
1021 			     __func__, session, session->last_cmd);
1022 	}
1023 
1024 	return ret;
1025 }
1026 
1027 static int j1939_simple_txnext(struct j1939_session *session)
1028 {
1029 	struct j1939_priv *priv = session->priv;
1030 	struct sk_buff *se_skb = j1939_session_skb_get(session);
1031 	struct sk_buff *skb;
1032 	int ret;
1033 
1034 	if (!se_skb)
1035 		return 0;
1036 
1037 	skb = skb_clone(se_skb, GFP_ATOMIC);
1038 	if (!skb) {
1039 		ret = -ENOMEM;
1040 		goto out_free;
1041 	}
1042 
1043 	can_skb_set_owner(skb, se_skb->sk);
1044 
1045 	j1939_tp_set_rxtimeout(session, J1939_SIMPLE_ECHO_TIMEOUT_MS);
1046 
1047 	ret = j1939_send_one(priv, skb);
1048 	if (ret)
1049 		goto out_free;
1050 
1051 	j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_SCHED);
1052 	j1939_sk_queue_activate_next(session);
1053 
1054  out_free:
1055 	if (ret)
1056 		kfree_skb(se_skb);
1057 	else
1058 		consume_skb(se_skb);
1059 
1060 	return ret;
1061 }
1062 
1063 static bool j1939_session_deactivate_locked(struct j1939_session *session)
1064 {
1065 	bool active = false;
1066 
1067 	lockdep_assert_held(&session->priv->active_session_list_lock);
1068 
1069 	if (session->state >= J1939_SESSION_ACTIVE &&
1070 	    session->state < J1939_SESSION_ACTIVE_MAX) {
1071 		active = true;
1072 
1073 		list_del_init(&session->active_session_list_entry);
1074 		session->state = J1939_SESSION_DONE;
1075 		j1939_session_put(session);
1076 	}
1077 
1078 	return active;
1079 }
1080 
1081 static bool j1939_session_deactivate(struct j1939_session *session)
1082 {
1083 	struct j1939_priv *priv = session->priv;
1084 	bool active;
1085 
1086 	j1939_session_list_lock(priv);
1087 	/* This function should be called with a session ref-count of at
1088 	 * least 2.
1089 	 */
1090 	WARN_ON_ONCE(kref_read(&session->kref) < 2);
1091 	active = j1939_session_deactivate_locked(session);
1092 	j1939_session_list_unlock(priv);
1093 
1094 	return active;
1095 }
1096 
1097 static void
1098 j1939_session_deactivate_activate_next(struct j1939_session *session)
1099 {
1100 	if (j1939_session_deactivate(session))
1101 		j1939_sk_queue_activate_next(session);
1102 }
1103 
1104 static void __j1939_session_cancel(struct j1939_session *session,
1105 				   enum j1939_xtp_abort err)
1106 {
1107 	struct j1939_priv *priv = session->priv;
1108 
1109 	WARN_ON_ONCE(!err);
1110 	lockdep_assert_held(&session->priv->active_session_list_lock);
1111 
1112 	session->err = j1939_xtp_abort_to_errno(priv, err);
1113 	session->state = J1939_SESSION_WAITING_ABORT;
1114 	/* do not send aborts on incoming broadcasts */
1115 	if (!j1939_cb_is_broadcast(&session->skcb)) {
1116 		j1939_xtp_tx_abort(priv, &session->skcb,
1117 				   !session->transmission,
1118 				   err, session->skcb.addr.pgn);
1119 	}
1120 
1121 	if (session->sk)
1122 		j1939_sk_send_loop_abort(session->sk, session->err);
1123 	else
1124 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
1125 }
1126 
1127 static void j1939_session_cancel(struct j1939_session *session,
1128 				 enum j1939_xtp_abort err)
1129 {
1130 	j1939_session_list_lock(session->priv);
1131 
1132 	if (session->state >= J1939_SESSION_ACTIVE &&
1133 	    session->state < J1939_SESSION_WAITING_ABORT) {
1134 		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
1135 		__j1939_session_cancel(session, err);
1136 	}
1137 
1138 	j1939_session_list_unlock(session->priv);
1139 }
1140 
1141 static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
1142 {
1143 	struct j1939_session *session =
1144 		container_of(hrtimer, struct j1939_session, txtimer);
1145 	struct j1939_priv *priv = session->priv;
1146 	int ret = 0;
1147 
1148 	if (session->skcb.addr.type == J1939_SIMPLE) {
1149 		ret = j1939_simple_txnext(session);
1150 	} else {
1151 		if (session->transmission)
1152 			ret = j1939_xtp_txnext_transmiter(session);
1153 		else
1154 			ret = j1939_xtp_txnext_receiver(session);
1155 	}
1156 
1157 	switch (ret) {
1158 	case -ENOBUFS:
1159 		/* Retry limit is currently arbitrary chosen */
1160 		if (session->tx_retry < J1939_XTP_TX_RETRY_LIMIT) {
1161 			session->tx_retry++;
1162 			j1939_tp_schedule_txtimer(session,
1163 						  10 + prandom_u32_max(16));
1164 		} else {
1165 			netdev_alert(priv->ndev, "%s: 0x%p: tx retry count reached\n",
1166 				     __func__, session);
1167 			session->err = -ENETUNREACH;
1168 			j1939_session_rxtimer_cancel(session);
1169 			j1939_session_deactivate_activate_next(session);
1170 		}
1171 		break;
1172 	case -ENETDOWN:
1173 		/* In this case we should get a netdev_event(), all active
1174 		 * sessions will be cleared by
1175 		 * j1939_cancel_all_active_sessions(). So handle this as an
1176 		 * error, but let j1939_cancel_all_active_sessions() do the
1177 		 * cleanup including propagation of the error to user space.
1178 		 */
1179 		break;
1180 	case -EOVERFLOW:
1181 		j1939_session_cancel(session, J1939_XTP_ABORT_ECTS_TOO_BIG);
1182 		break;
1183 	case 0:
1184 		session->tx_retry = 0;
1185 		break;
1186 	default:
1187 		netdev_alert(priv->ndev, "%s: 0x%p: tx aborted with unknown reason: %i\n",
1188 			     __func__, session, ret);
1189 		if (session->skcb.addr.type != J1939_SIMPLE) {
1190 			j1939_session_cancel(session, J1939_XTP_ABORT_OTHER);
1191 		} else {
1192 			session->err = ret;
1193 			j1939_session_rxtimer_cancel(session);
1194 			j1939_session_deactivate_activate_next(session);
1195 		}
1196 	}
1197 
1198 	j1939_session_put(session);
1199 
1200 	return HRTIMER_NORESTART;
1201 }
1202 
1203 static void j1939_session_completed(struct j1939_session *session)
1204 {
1205 	struct sk_buff *se_skb;
1206 
1207 	if (!session->transmission) {
1208 		se_skb = j1939_session_skb_get(session);
1209 		/* distribute among j1939 receivers */
1210 		j1939_sk_recv(session->priv, se_skb);
1211 		consume_skb(se_skb);
1212 	}
1213 
1214 	j1939_session_deactivate_activate_next(session);
1215 }
1216 
1217 static enum hrtimer_restart j1939_tp_rxtimer(struct hrtimer *hrtimer)
1218 {
1219 	struct j1939_session *session = container_of(hrtimer,
1220 						     struct j1939_session,
1221 						     rxtimer);
1222 	struct j1939_priv *priv = session->priv;
1223 
1224 	if (session->state == J1939_SESSION_WAITING_ABORT) {
1225 		netdev_alert(priv->ndev, "%s: 0x%p: abort rx timeout. Force session deactivation\n",
1226 			     __func__, session);
1227 
1228 		j1939_session_deactivate_activate_next(session);
1229 
1230 	} else if (session->skcb.addr.type == J1939_SIMPLE) {
1231 		netdev_alert(priv->ndev, "%s: 0x%p: Timeout. Failed to send simple message.\n",
1232 			     __func__, session);
1233 
1234 		/* The message is probably stuck in the CAN controller and can
1235 		 * be send as soon as CAN bus is in working state again.
1236 		 */
1237 		session->err = -ETIME;
1238 		j1939_session_deactivate(session);
1239 	} else {
1240 		j1939_session_list_lock(session->priv);
1241 		if (session->state >= J1939_SESSION_ACTIVE &&
1242 		    session->state < J1939_SESSION_ACTIVE_MAX) {
1243 			netdev_alert(priv->ndev, "%s: 0x%p: rx timeout, send abort\n",
1244 				     __func__, session);
1245 			j1939_session_get(session);
1246 			hrtimer_start(&session->rxtimer,
1247 				      ms_to_ktime(J1939_XTP_ABORT_TIMEOUT_MS),
1248 				      HRTIMER_MODE_REL_SOFT);
1249 			__j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
1250 		}
1251 		j1939_session_list_unlock(session->priv);
1252 	}
1253 
1254 	j1939_session_put(session);
1255 
1256 	return HRTIMER_NORESTART;
1257 }
1258 
1259 static bool j1939_xtp_rx_cmd_bad_pgn(struct j1939_session *session,
1260 				     const struct sk_buff *skb)
1261 {
1262 	const struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1263 	pgn_t pgn = j1939_xtp_ctl_to_pgn(skb->data);
1264 	struct j1939_priv *priv = session->priv;
1265 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1266 	u8 cmd = skb->data[0];
1267 
1268 	if (session->skcb.addr.pgn == pgn)
1269 		return false;
1270 
1271 	switch (cmd) {
1272 	case J1939_TP_CMD_BAM:
1273 		abort = J1939_XTP_NO_ABORT;
1274 		break;
1275 
1276 	case J1939_ETP_CMD_RTS:
1277 		fallthrough;
1278 	case J1939_TP_CMD_RTS:
1279 		abort = J1939_XTP_ABORT_BUSY;
1280 		break;
1281 
1282 	case J1939_ETP_CMD_CTS:
1283 		fallthrough;
1284 	case J1939_TP_CMD_CTS:
1285 		abort = J1939_XTP_ABORT_ECTS_UNXPECTED_PGN;
1286 		break;
1287 
1288 	case J1939_ETP_CMD_DPO:
1289 		abort = J1939_XTP_ABORT_BAD_EDPO_PGN;
1290 		break;
1291 
1292 	case J1939_ETP_CMD_EOMA:
1293 		fallthrough;
1294 	case J1939_TP_CMD_EOMA:
1295 		abort = J1939_XTP_ABORT_OTHER;
1296 		break;
1297 
1298 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
1299 		abort = J1939_XTP_NO_ABORT;
1300 		break;
1301 
1302 	default:
1303 		WARN_ON_ONCE(1);
1304 		break;
1305 	}
1306 
1307 	netdev_warn(priv->ndev, "%s: 0x%p: CMD 0x%02x with PGN 0x%05x for running session with different PGN 0x%05x.\n",
1308 		    __func__, session, cmd, pgn, session->skcb.addr.pgn);
1309 	if (abort != J1939_XTP_NO_ABORT)
1310 		j1939_xtp_tx_abort(priv, skcb, true, abort, pgn);
1311 
1312 	return true;
1313 }
1314 
1315 static void j1939_xtp_rx_abort_one(struct j1939_priv *priv, struct sk_buff *skb,
1316 				   bool reverse, bool transmitter)
1317 {
1318 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1319 	struct j1939_session *session;
1320 	u8 abort = skb->data[1];
1321 
1322 	session = j1939_session_get_by_addr(priv, &skcb->addr, reverse,
1323 					    transmitter);
1324 	if (!session)
1325 		return;
1326 
1327 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1328 		goto abort_put;
1329 
1330 	netdev_info(priv->ndev, "%s: 0x%p: 0x%05x: (%u) %s\n", __func__,
1331 		    session, j1939_xtp_ctl_to_pgn(skb->data), abort,
1332 		    j1939_xtp_abort_to_str(abort));
1333 
1334 	j1939_session_timers_cancel(session);
1335 	session->err = j1939_xtp_abort_to_errno(priv, abort);
1336 	if (session->sk)
1337 		j1939_sk_send_loop_abort(session->sk, session->err);
1338 	else
1339 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
1340 	j1939_session_deactivate_activate_next(session);
1341 
1342 abort_put:
1343 	j1939_session_put(session);
1344 }
1345 
1346 /* abort packets may come in 2 directions */
1347 static void
1348 j1939_xtp_rx_abort(struct j1939_priv *priv, struct sk_buff *skb,
1349 		   bool transmitter)
1350 {
1351 	j1939_xtp_rx_abort_one(priv, skb, false, transmitter);
1352 	j1939_xtp_rx_abort_one(priv, skb, true, transmitter);
1353 }
1354 
1355 static void
1356 j1939_xtp_rx_eoma_one(struct j1939_session *session, struct sk_buff *skb)
1357 {
1358 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1359 	const u8 *dat;
1360 	int len;
1361 
1362 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1363 		return;
1364 
1365 	dat = skb->data;
1366 
1367 	if (skcb->addr.type == J1939_ETP)
1368 		len = j1939_etp_ctl_to_size(dat);
1369 	else
1370 		len = j1939_tp_ctl_to_size(dat);
1371 
1372 	if (session->total_message_size != len) {
1373 		netdev_warn_once(session->priv->ndev,
1374 				 "%s: 0x%p: Incorrect size. Expected: %i; got: %i.\n",
1375 				 __func__, session, session->total_message_size,
1376 				 len);
1377 	}
1378 
1379 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1380 
1381 	session->pkt.tx_acked = session->pkt.total;
1382 	j1939_session_timers_cancel(session);
1383 	/* transmitted without problems */
1384 	j1939_session_completed(session);
1385 }
1386 
1387 static void
1388 j1939_xtp_rx_eoma(struct j1939_priv *priv, struct sk_buff *skb,
1389 		  bool transmitter)
1390 {
1391 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1392 	struct j1939_session *session;
1393 
1394 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1395 					    transmitter);
1396 	if (!session)
1397 		return;
1398 
1399 	j1939_xtp_rx_eoma_one(session, skb);
1400 	j1939_session_put(session);
1401 }
1402 
1403 static void
1404 j1939_xtp_rx_cts_one(struct j1939_session *session, struct sk_buff *skb)
1405 {
1406 	enum j1939_xtp_abort err = J1939_XTP_ABORT_FAULT;
1407 	unsigned int pkt;
1408 	const u8 *dat;
1409 
1410 	dat = skb->data;
1411 
1412 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1413 		return;
1414 
1415 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1416 
1417 	if (session->last_cmd == dat[0]) {
1418 		err = J1939_XTP_ABORT_DUP_SEQ;
1419 		goto out_session_cancel;
1420 	}
1421 
1422 	if (session->skcb.addr.type == J1939_ETP)
1423 		pkt = j1939_etp_ctl_to_packet(dat);
1424 	else
1425 		pkt = dat[2];
1426 
1427 	if (!pkt)
1428 		goto out_session_cancel;
1429 	else if (dat[1] > session->pkt.block /* 0xff for etp */)
1430 		goto out_session_cancel;
1431 
1432 	/* set packet counters only when not CTS(0) */
1433 	session->pkt.tx_acked = pkt - 1;
1434 	j1939_session_skb_drop_old(session);
1435 	session->pkt.last = session->pkt.tx_acked + dat[1];
1436 	if (session->pkt.last > session->pkt.total)
1437 		/* safety measure */
1438 		session->pkt.last = session->pkt.total;
1439 	/* TODO: do not set tx here, do it in txtimer */
1440 	session->pkt.tx = session->pkt.tx_acked;
1441 
1442 	session->last_cmd = dat[0];
1443 	if (dat[1]) {
1444 		j1939_tp_set_rxtimeout(session, 1250);
1445 		if (session->transmission) {
1446 			if (session->pkt.tx_acked)
1447 				j1939_sk_errqueue(session,
1448 						  J1939_ERRQUEUE_TX_SCHED);
1449 			j1939_session_txtimer_cancel(session);
1450 			j1939_tp_schedule_txtimer(session, 0);
1451 		}
1452 	} else {
1453 		/* CTS(0) */
1454 		j1939_tp_set_rxtimeout(session, 550);
1455 	}
1456 	return;
1457 
1458  out_session_cancel:
1459 	j1939_session_timers_cancel(session);
1460 	j1939_session_cancel(session, err);
1461 }
1462 
1463 static void
1464 j1939_xtp_rx_cts(struct j1939_priv *priv, struct sk_buff *skb, bool transmitter)
1465 {
1466 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1467 	struct j1939_session *session;
1468 
1469 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1470 					    transmitter);
1471 	if (!session)
1472 		return;
1473 	j1939_xtp_rx_cts_one(session, skb);
1474 	j1939_session_put(session);
1475 }
1476 
1477 static struct j1939_session *j1939_session_new(struct j1939_priv *priv,
1478 					       struct sk_buff *skb, size_t size)
1479 {
1480 	struct j1939_session *session;
1481 	struct j1939_sk_buff_cb *skcb;
1482 
1483 	session = kzalloc(sizeof(*session), gfp_any());
1484 	if (!session)
1485 		return NULL;
1486 
1487 	INIT_LIST_HEAD(&session->active_session_list_entry);
1488 	INIT_LIST_HEAD(&session->sk_session_queue_entry);
1489 	kref_init(&session->kref);
1490 
1491 	j1939_priv_get(priv);
1492 	session->priv = priv;
1493 	session->total_message_size = size;
1494 	session->state = J1939_SESSION_NEW;
1495 
1496 	skb_queue_head_init(&session->skb_queue);
1497 	skb_queue_tail(&session->skb_queue, skb);
1498 
1499 	skcb = j1939_skb_to_cb(skb);
1500 	memcpy(&session->skcb, skcb, sizeof(session->skcb));
1501 
1502 	hrtimer_init(&session->txtimer, CLOCK_MONOTONIC,
1503 		     HRTIMER_MODE_REL_SOFT);
1504 	session->txtimer.function = j1939_tp_txtimer;
1505 	hrtimer_init(&session->rxtimer, CLOCK_MONOTONIC,
1506 		     HRTIMER_MODE_REL_SOFT);
1507 	session->rxtimer.function = j1939_tp_rxtimer;
1508 
1509 	netdev_dbg(priv->ndev, "%s: 0x%p: sa: %02x, da: %02x\n",
1510 		   __func__, session, skcb->addr.sa, skcb->addr.da);
1511 
1512 	return session;
1513 }
1514 
1515 static struct
1516 j1939_session *j1939_session_fresh_new(struct j1939_priv *priv,
1517 				       int size,
1518 				       const struct j1939_sk_buff_cb *rel_skcb)
1519 {
1520 	struct sk_buff *skb;
1521 	struct j1939_sk_buff_cb *skcb;
1522 	struct j1939_session *session;
1523 
1524 	skb = alloc_skb(size + sizeof(struct can_skb_priv), GFP_ATOMIC);
1525 	if (unlikely(!skb))
1526 		return NULL;
1527 
1528 	skb->dev = priv->ndev;
1529 	can_skb_reserve(skb);
1530 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
1531 	can_skb_prv(skb)->skbcnt = 0;
1532 	skcb = j1939_skb_to_cb(skb);
1533 	memcpy(skcb, rel_skcb, sizeof(*skcb));
1534 
1535 	session = j1939_session_new(priv, skb, size);
1536 	if (!session) {
1537 		kfree_skb(skb);
1538 		return NULL;
1539 	}
1540 
1541 	/* alloc data area */
1542 	skb_put(skb, size);
1543 	/* skb is recounted in j1939_session_new() */
1544 	return session;
1545 }
1546 
1547 int j1939_session_activate(struct j1939_session *session)
1548 {
1549 	struct j1939_priv *priv = session->priv;
1550 	struct j1939_session *active = NULL;
1551 	int ret = 0;
1552 
1553 	j1939_session_list_lock(priv);
1554 	if (session->skcb.addr.type != J1939_SIMPLE)
1555 		active = j1939_session_get_by_addr_locked(priv,
1556 							  &priv->active_session_list,
1557 							  &session->skcb.addr, false,
1558 							  session->transmission);
1559 	if (active) {
1560 		j1939_session_put(active);
1561 		ret = -EAGAIN;
1562 	} else {
1563 		WARN_ON_ONCE(session->state != J1939_SESSION_NEW);
1564 		list_add_tail(&session->active_session_list_entry,
1565 			      &priv->active_session_list);
1566 		j1939_session_get(session);
1567 		session->state = J1939_SESSION_ACTIVE;
1568 
1569 		netdev_dbg(session->priv->ndev, "%s: 0x%p\n",
1570 			   __func__, session);
1571 	}
1572 	j1939_session_list_unlock(priv);
1573 
1574 	return ret;
1575 }
1576 
1577 static struct
1578 j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
1579 					    struct sk_buff *skb)
1580 {
1581 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1582 	struct j1939_sk_buff_cb skcb = *j1939_skb_to_cb(skb);
1583 	struct j1939_session *session;
1584 	const u8 *dat;
1585 	pgn_t pgn;
1586 	int len;
1587 
1588 	netdev_dbg(priv->ndev, "%s\n", __func__);
1589 
1590 	dat = skb->data;
1591 	pgn = j1939_xtp_ctl_to_pgn(dat);
1592 	skcb.addr.pgn = pgn;
1593 
1594 	if (!j1939_sk_recv_match(priv, &skcb))
1595 		return NULL;
1596 
1597 	if (skcb.addr.type == J1939_ETP) {
1598 		len = j1939_etp_ctl_to_size(dat);
1599 		if (len > J1939_MAX_ETP_PACKET_SIZE)
1600 			abort = J1939_XTP_ABORT_FAULT;
1601 		else if (len > priv->tp_max_packet_size)
1602 			abort = J1939_XTP_ABORT_RESOURCE;
1603 		else if (len <= J1939_MAX_TP_PACKET_SIZE)
1604 			abort = J1939_XTP_ABORT_FAULT;
1605 	} else {
1606 		len = j1939_tp_ctl_to_size(dat);
1607 		if (len > J1939_MAX_TP_PACKET_SIZE)
1608 			abort = J1939_XTP_ABORT_FAULT;
1609 		else if (len > priv->tp_max_packet_size)
1610 			abort = J1939_XTP_ABORT_RESOURCE;
1611 		else if (len < J1939_MIN_TP_PACKET_SIZE)
1612 			abort = J1939_XTP_ABORT_FAULT;
1613 	}
1614 
1615 	if (abort != J1939_XTP_NO_ABORT) {
1616 		j1939_xtp_tx_abort(priv, &skcb, true, abort, pgn);
1617 		return NULL;
1618 	}
1619 
1620 	session = j1939_session_fresh_new(priv, len, &skcb);
1621 	if (!session) {
1622 		j1939_xtp_tx_abort(priv, &skcb, true,
1623 				   J1939_XTP_ABORT_RESOURCE, pgn);
1624 		return NULL;
1625 	}
1626 
1627 	/* initialize the control buffer: plain copy */
1628 	session->pkt.total = (len + 6) / 7;
1629 	session->pkt.block = 0xff;
1630 	if (skcb.addr.type != J1939_ETP) {
1631 		if (dat[3] != session->pkt.total)
1632 			netdev_alert(priv->ndev, "%s: 0x%p: strange total, %u != %u\n",
1633 				     __func__, session, session->pkt.total,
1634 				     dat[3]);
1635 		session->pkt.total = dat[3];
1636 		session->pkt.block = min(dat[3], dat[4]);
1637 	}
1638 
1639 	session->pkt.rx = 0;
1640 	session->pkt.tx = 0;
1641 
1642 	session->tskey = priv->rx_tskey++;
1643 	j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_RTS);
1644 
1645 	WARN_ON_ONCE(j1939_session_activate(session));
1646 
1647 	return session;
1648 }
1649 
1650 static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
1651 					   struct sk_buff *skb)
1652 {
1653 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1654 	struct j1939_priv *priv = session->priv;
1655 
1656 	if (!session->transmission) {
1657 		if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1658 			return -EBUSY;
1659 
1660 		/* RTS on active session */
1661 		j1939_session_timers_cancel(session);
1662 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1663 	}
1664 
1665 	if (session->last_cmd != 0) {
1666 		/* we received a second rts on the same connection */
1667 		netdev_alert(priv->ndev, "%s: 0x%p: connection exists (%02x %02x). last cmd: %x\n",
1668 			     __func__, session, skcb->addr.sa, skcb->addr.da,
1669 			     session->last_cmd);
1670 
1671 		j1939_session_timers_cancel(session);
1672 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1673 
1674 		return -EBUSY;
1675 	}
1676 
1677 	if (session->skcb.addr.sa != skcb->addr.sa ||
1678 	    session->skcb.addr.da != skcb->addr.da)
1679 		netdev_warn(priv->ndev, "%s: 0x%p: session->skcb.addr.sa=0x%02x skcb->addr.sa=0x%02x session->skcb.addr.da=0x%02x skcb->addr.da=0x%02x\n",
1680 			    __func__, session,
1681 			    session->skcb.addr.sa, skcb->addr.sa,
1682 			    session->skcb.addr.da, skcb->addr.da);
1683 	/* make sure 'sa' & 'da' are correct !
1684 	 * They may be 'not filled in yet' for sending
1685 	 * skb's, since they did not pass the Address Claim ever.
1686 	 */
1687 	session->skcb.addr.sa = skcb->addr.sa;
1688 	session->skcb.addr.da = skcb->addr.da;
1689 
1690 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1691 
1692 	return 0;
1693 }
1694 
1695 static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
1696 			     bool transmitter)
1697 {
1698 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1699 	struct j1939_session *session;
1700 	u8 cmd = skb->data[0];
1701 
1702 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1703 					    transmitter);
1704 
1705 	if (!session) {
1706 		if (transmitter) {
1707 			/* If we're the transmitter and this function is called,
1708 			 * we received our own RTS. A session has already been
1709 			 * created.
1710 			 *
1711 			 * For some reasons however it might have been destroyed
1712 			 * already. So don't create a new one here (using
1713 			 * "j1939_xtp_rx_rts_session_new()") as this will be a
1714 			 * receiver session.
1715 			 *
1716 			 * The reasons the session is already destroyed might
1717 			 * be:
1718 			 * - user space closed socket was and the session was
1719 			 *   aborted
1720 			 * - session was aborted due to external abort message
1721 			 */
1722 			return;
1723 		}
1724 		session = j1939_xtp_rx_rts_session_new(priv, skb);
1725 		if (!session) {
1726 			if (cmd == J1939_TP_CMD_BAM && j1939_sk_recv_match(priv, skcb))
1727 				netdev_info(priv->ndev, "%s: failed to create TP BAM session\n",
1728 					    __func__);
1729 			return;
1730 		}
1731 	} else {
1732 		if (j1939_xtp_rx_rts_session_active(session, skb)) {
1733 			j1939_session_put(session);
1734 			return;
1735 		}
1736 	}
1737 	session->last_cmd = cmd;
1738 
1739 	if (cmd == J1939_TP_CMD_BAM) {
1740 		if (!session->transmission)
1741 			j1939_tp_set_rxtimeout(session, 750);
1742 	} else {
1743 		if (!session->transmission) {
1744 			j1939_session_txtimer_cancel(session);
1745 			j1939_tp_schedule_txtimer(session, 0);
1746 		}
1747 		j1939_tp_set_rxtimeout(session, 1250);
1748 	}
1749 
1750 	j1939_session_put(session);
1751 }
1752 
1753 static void j1939_xtp_rx_dpo_one(struct j1939_session *session,
1754 				 struct sk_buff *skb)
1755 {
1756 	const u8 *dat = skb->data;
1757 
1758 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1759 		return;
1760 
1761 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1762 
1763 	/* transmitted without problems */
1764 	session->pkt.dpo = j1939_etp_ctl_to_packet(skb->data);
1765 	session->last_cmd = dat[0];
1766 	j1939_tp_set_rxtimeout(session, 750);
1767 
1768 	if (!session->transmission)
1769 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_DPO);
1770 }
1771 
1772 static void j1939_xtp_rx_dpo(struct j1939_priv *priv, struct sk_buff *skb,
1773 			     bool transmitter)
1774 {
1775 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1776 	struct j1939_session *session;
1777 
1778 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1779 					    transmitter);
1780 	if (!session) {
1781 		netdev_info(priv->ndev,
1782 			    "%s: no connection found\n", __func__);
1783 		return;
1784 	}
1785 
1786 	j1939_xtp_rx_dpo_one(session, skb);
1787 	j1939_session_put(session);
1788 }
1789 
1790 static void j1939_xtp_rx_dat_one(struct j1939_session *session,
1791 				 struct sk_buff *skb)
1792 {
1793 	enum j1939_xtp_abort abort = J1939_XTP_ABORT_FAULT;
1794 	struct j1939_priv *priv = session->priv;
1795 	struct j1939_sk_buff_cb *skcb, *se_skcb;
1796 	struct sk_buff *se_skb = NULL;
1797 	const u8 *dat;
1798 	u8 *tpdat;
1799 	int offset;
1800 	int nbytes;
1801 	bool final = false;
1802 	bool remain = false;
1803 	bool do_cts_eoma = false;
1804 	int packet;
1805 
1806 	skcb = j1939_skb_to_cb(skb);
1807 	dat = skb->data;
1808 	if (skb->len != 8) {
1809 		/* makes no sense */
1810 		abort = J1939_XTP_ABORT_UNEXPECTED_DATA;
1811 		goto out_session_cancel;
1812 	}
1813 
1814 	switch (session->last_cmd) {
1815 	case 0xff:
1816 		break;
1817 	case J1939_ETP_CMD_DPO:
1818 		if (skcb->addr.type == J1939_ETP)
1819 			break;
1820 		fallthrough;
1821 	case J1939_TP_CMD_BAM:
1822 		fallthrough;
1823 	case J1939_TP_CMD_CTS:
1824 		if (skcb->addr.type != J1939_ETP)
1825 			break;
1826 		fallthrough;
1827 	default:
1828 		netdev_info(priv->ndev, "%s: 0x%p: last %02x\n", __func__,
1829 			    session, session->last_cmd);
1830 		goto out_session_cancel;
1831 	}
1832 
1833 	packet = (dat[0] - 1 + session->pkt.dpo);
1834 	if (packet > session->pkt.total ||
1835 	    (session->pkt.rx + 1) > session->pkt.total) {
1836 		netdev_info(priv->ndev, "%s: 0x%p: should have been completed\n",
1837 			    __func__, session);
1838 		goto out_session_cancel;
1839 	}
1840 
1841 	se_skb = j1939_session_skb_get_by_offset(session, packet * 7);
1842 	if (!se_skb) {
1843 		netdev_warn(priv->ndev, "%s: 0x%p: no skb found\n", __func__,
1844 			    session);
1845 		goto out_session_cancel;
1846 	}
1847 
1848 	se_skcb = j1939_skb_to_cb(se_skb);
1849 	offset = packet * 7 - se_skcb->offset;
1850 	nbytes = se_skb->len - offset;
1851 	if (nbytes > 7)
1852 		nbytes = 7;
1853 	if (nbytes <= 0 || (nbytes + 1) > skb->len) {
1854 		netdev_info(priv->ndev, "%s: 0x%p: nbytes %i, len %i\n",
1855 			    __func__, session, nbytes, skb->len);
1856 		goto out_session_cancel;
1857 	}
1858 
1859 	tpdat = se_skb->data;
1860 	if (!session->transmission) {
1861 		memcpy(&tpdat[offset], &dat[1], nbytes);
1862 	} else {
1863 		int err;
1864 
1865 		err = memcmp(&tpdat[offset], &dat[1], nbytes);
1866 		if (err)
1867 			netdev_err_once(priv->ndev,
1868 					"%s: 0x%p: Data of RX-looped back packet (%*ph) doesn't match TX data (%*ph)!\n",
1869 					__func__, session,
1870 					nbytes, &dat[1],
1871 					nbytes, &tpdat[offset]);
1872 	}
1873 
1874 	if (packet == session->pkt.rx)
1875 		session->pkt.rx++;
1876 
1877 	if (se_skcb->addr.type != J1939_ETP &&
1878 	    j1939_cb_is_broadcast(&session->skcb)) {
1879 		if (session->pkt.rx >= session->pkt.total)
1880 			final = true;
1881 		else
1882 			remain = true;
1883 	} else {
1884 		/* never final, an EOMA must follow */
1885 		if (session->pkt.rx >= session->pkt.last)
1886 			do_cts_eoma = true;
1887 	}
1888 
1889 	if (final) {
1890 		j1939_session_timers_cancel(session);
1891 		j1939_session_completed(session);
1892 	} else if (remain) {
1893 		if (!session->transmission)
1894 			j1939_tp_set_rxtimeout(session, 750);
1895 	} else if (do_cts_eoma) {
1896 		j1939_tp_set_rxtimeout(session, 1250);
1897 		if (!session->transmission)
1898 			j1939_tp_schedule_txtimer(session, 0);
1899 	} else {
1900 		j1939_tp_set_rxtimeout(session, 750);
1901 	}
1902 	session->last_cmd = 0xff;
1903 	consume_skb(se_skb);
1904 	j1939_session_put(session);
1905 
1906 	return;
1907 
1908  out_session_cancel:
1909 	kfree_skb(se_skb);
1910 	j1939_session_timers_cancel(session);
1911 	j1939_session_cancel(session, abort);
1912 	j1939_session_put(session);
1913 }
1914 
1915 static void j1939_xtp_rx_dat(struct j1939_priv *priv, struct sk_buff *skb)
1916 {
1917 	struct j1939_sk_buff_cb *skcb;
1918 	struct j1939_session *session;
1919 
1920 	skcb = j1939_skb_to_cb(skb);
1921 
1922 	if (j1939_tp_im_transmitter(skcb)) {
1923 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1924 						    true);
1925 		if (!session)
1926 			netdev_info(priv->ndev, "%s: no tx connection found\n",
1927 				    __func__);
1928 		else
1929 			j1939_xtp_rx_dat_one(session, skb);
1930 	}
1931 
1932 	if (j1939_tp_im_receiver(skcb)) {
1933 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1934 						    false);
1935 		if (!session)
1936 			netdev_info(priv->ndev, "%s: no rx connection found\n",
1937 				    __func__);
1938 		else
1939 			j1939_xtp_rx_dat_one(session, skb);
1940 	}
1941 
1942 	if (j1939_cb_is_broadcast(skcb)) {
1943 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1944 						    false);
1945 		if (session)
1946 			j1939_xtp_rx_dat_one(session, skb);
1947 	}
1948 }
1949 
1950 /* j1939 main intf */
1951 struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
1952 				    struct sk_buff *skb, size_t size)
1953 {
1954 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1955 	struct j1939_session *session;
1956 	int ret;
1957 
1958 	if (skcb->addr.pgn == J1939_TP_PGN_DAT ||
1959 	    skcb->addr.pgn == J1939_TP_PGN_CTL ||
1960 	    skcb->addr.pgn == J1939_ETP_PGN_DAT ||
1961 	    skcb->addr.pgn == J1939_ETP_PGN_CTL)
1962 		/* avoid conflict */
1963 		return ERR_PTR(-EDOM);
1964 
1965 	if (size > priv->tp_max_packet_size)
1966 		return ERR_PTR(-EMSGSIZE);
1967 
1968 	if (size <= 8)
1969 		skcb->addr.type = J1939_SIMPLE;
1970 	else if (size > J1939_MAX_TP_PACKET_SIZE)
1971 		skcb->addr.type = J1939_ETP;
1972 	else
1973 		skcb->addr.type = J1939_TP;
1974 
1975 	if (skcb->addr.type == J1939_ETP &&
1976 	    j1939_cb_is_broadcast(skcb))
1977 		return ERR_PTR(-EDESTADDRREQ);
1978 
1979 	/* fill in addresses from names */
1980 	ret = j1939_ac_fixup(priv, skb);
1981 	if (unlikely(ret))
1982 		return ERR_PTR(ret);
1983 
1984 	/* fix DST flags, it may be used there soon */
1985 	if (j1939_address_is_unicast(skcb->addr.da) &&
1986 	    priv->ents[skcb->addr.da].nusers)
1987 		skcb->flags |= J1939_ECU_LOCAL_DST;
1988 
1989 	/* src is always local, I'm sending ... */
1990 	skcb->flags |= J1939_ECU_LOCAL_SRC;
1991 
1992 	/* prepare new session */
1993 	session = j1939_session_new(priv, skb, size);
1994 	if (!session)
1995 		return ERR_PTR(-ENOMEM);
1996 
1997 	/* skb is recounted in j1939_session_new() */
1998 	sock_hold(skb->sk);
1999 	session->sk = skb->sk;
2000 	session->transmission = true;
2001 	session->pkt.total = (size + 6) / 7;
2002 	session->pkt.block = skcb->addr.type == J1939_ETP ? 255 :
2003 		min(j1939_tp_block ?: 255, session->pkt.total);
2004 
2005 	if (j1939_cb_is_broadcast(&session->skcb))
2006 		/* set the end-packet for broadcast */
2007 		session->pkt.last = session->pkt.total;
2008 
2009 	skcb->tskey = atomic_inc_return(&session->sk->sk_tskey) - 1;
2010 	session->tskey = skcb->tskey;
2011 
2012 	return session;
2013 }
2014 
2015 static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
2016 {
2017 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
2018 	int extd = J1939_TP;
2019 	u8 cmd = skb->data[0];
2020 
2021 	switch (cmd) {
2022 	case J1939_ETP_CMD_RTS:
2023 		extd = J1939_ETP;
2024 		fallthrough;
2025 	case J1939_TP_CMD_BAM:
2026 		if (cmd == J1939_TP_CMD_BAM && !j1939_cb_is_broadcast(skcb)) {
2027 			netdev_err_once(priv->ndev, "%s: BAM to unicast (%02x), ignoring!\n",
2028 					__func__, skcb->addr.sa);
2029 			return;
2030 		}
2031 		fallthrough;
2032 	case J1939_TP_CMD_RTS:
2033 		if (skcb->addr.type != extd)
2034 			return;
2035 
2036 		if (cmd == J1939_TP_CMD_RTS && j1939_cb_is_broadcast(skcb)) {
2037 			netdev_alert(priv->ndev, "%s: rts without destination (%02x)\n",
2038 				     __func__, skcb->addr.sa);
2039 			return;
2040 		}
2041 
2042 		if (j1939_tp_im_transmitter(skcb))
2043 			j1939_xtp_rx_rts(priv, skb, true);
2044 
2045 		if (j1939_tp_im_receiver(skcb) || j1939_cb_is_broadcast(skcb))
2046 			j1939_xtp_rx_rts(priv, skb, false);
2047 
2048 		break;
2049 
2050 	case J1939_ETP_CMD_CTS:
2051 		extd = J1939_ETP;
2052 		fallthrough;
2053 	case J1939_TP_CMD_CTS:
2054 		if (skcb->addr.type != extd)
2055 			return;
2056 
2057 		if (j1939_tp_im_transmitter(skcb))
2058 			j1939_xtp_rx_cts(priv, skb, false);
2059 
2060 		if (j1939_tp_im_receiver(skcb))
2061 			j1939_xtp_rx_cts(priv, skb, true);
2062 
2063 		break;
2064 
2065 	case J1939_ETP_CMD_DPO:
2066 		if (skcb->addr.type != J1939_ETP)
2067 			return;
2068 
2069 		if (j1939_tp_im_transmitter(skcb))
2070 			j1939_xtp_rx_dpo(priv, skb, true);
2071 
2072 		if (j1939_tp_im_receiver(skcb))
2073 			j1939_xtp_rx_dpo(priv, skb, false);
2074 
2075 		break;
2076 
2077 	case J1939_ETP_CMD_EOMA:
2078 		extd = J1939_ETP;
2079 		fallthrough;
2080 	case J1939_TP_CMD_EOMA:
2081 		if (skcb->addr.type != extd)
2082 			return;
2083 
2084 		if (j1939_tp_im_transmitter(skcb))
2085 			j1939_xtp_rx_eoma(priv, skb, false);
2086 
2087 		if (j1939_tp_im_receiver(skcb))
2088 			j1939_xtp_rx_eoma(priv, skb, true);
2089 
2090 		break;
2091 
2092 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
2093 		if (j1939_cb_is_broadcast(skcb)) {
2094 			netdev_err_once(priv->ndev, "%s: abort to broadcast (%02x), ignoring!\n",
2095 					__func__, skcb->addr.sa);
2096 			return;
2097 		}
2098 
2099 		if (j1939_tp_im_transmitter(skcb))
2100 			j1939_xtp_rx_abort(priv, skb, true);
2101 
2102 		if (j1939_tp_im_receiver(skcb))
2103 			j1939_xtp_rx_abort(priv, skb, false);
2104 
2105 		break;
2106 	default:
2107 		return;
2108 	}
2109 }
2110 
2111 int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb)
2112 {
2113 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
2114 
2115 	if (!j1939_tp_im_involved_anydir(skcb) && !j1939_cb_is_broadcast(skcb))
2116 		return 0;
2117 
2118 	switch (skcb->addr.pgn) {
2119 	case J1939_ETP_PGN_DAT:
2120 		skcb->addr.type = J1939_ETP;
2121 		fallthrough;
2122 	case J1939_TP_PGN_DAT:
2123 		j1939_xtp_rx_dat(priv, skb);
2124 		break;
2125 
2126 	case J1939_ETP_PGN_CTL:
2127 		skcb->addr.type = J1939_ETP;
2128 		fallthrough;
2129 	case J1939_TP_PGN_CTL:
2130 		if (skb->len < 8)
2131 			return 0; /* Don't care. Nothing to extract here */
2132 
2133 		j1939_tp_cmd_recv(priv, skb);
2134 		break;
2135 	default:
2136 		return 0; /* no problem */
2137 	}
2138 	return 1; /* "I processed the message" */
2139 }
2140 
2141 void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb)
2142 {
2143 	struct j1939_session *session;
2144 
2145 	if (!skb->sk)
2146 		return;
2147 
2148 	if (skb->sk->sk_family != AF_CAN ||
2149 	    skb->sk->sk_protocol != CAN_J1939)
2150 		return;
2151 
2152 	j1939_session_list_lock(priv);
2153 	session = j1939_session_get_simple(priv, skb);
2154 	j1939_session_list_unlock(priv);
2155 	if (!session) {
2156 		netdev_warn(priv->ndev,
2157 			    "%s: Received already invalidated message\n",
2158 			    __func__);
2159 		return;
2160 	}
2161 
2162 	j1939_session_timers_cancel(session);
2163 	j1939_session_deactivate(session);
2164 	j1939_session_put(session);
2165 }
2166 
2167 int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk)
2168 {
2169 	struct j1939_session *session, *saved;
2170 
2171 	netdev_dbg(priv->ndev, "%s, sk: %p\n", __func__, sk);
2172 	j1939_session_list_lock(priv);
2173 	list_for_each_entry_safe(session, saved,
2174 				 &priv->active_session_list,
2175 				 active_session_list_entry) {
2176 		if (!sk || sk == session->sk) {
2177 			if (hrtimer_try_to_cancel(&session->txtimer) == 1)
2178 				j1939_session_put(session);
2179 			if (hrtimer_try_to_cancel(&session->rxtimer) == 1)
2180 				j1939_session_put(session);
2181 
2182 			session->err = ESHUTDOWN;
2183 			j1939_session_deactivate_locked(session);
2184 		}
2185 	}
2186 	j1939_session_list_unlock(priv);
2187 	return NOTIFY_DONE;
2188 }
2189 
2190 void j1939_tp_init(struct j1939_priv *priv)
2191 {
2192 	spin_lock_init(&priv->active_session_list_lock);
2193 	INIT_LIST_HEAD(&priv->active_session_list);
2194 	priv->tp_max_packet_size = J1939_MAX_ETP_PACKET_SIZE;
2195 }
2196