can: add support of SAE J1939 protocol

SAE J1939 is the vehicle bus recommended practice used for communication
and diagnostics among vehicle components. Originating in the car and
heavy-duty truck industry in the United States, it is now widely used in
other parts of the world.

J1939, ISO 11783 and NMEA 2000 all share the same high level protocol.
SAE J1939 can be considered the replacement for the older SAE J1708 and
SAE J1587 specifications.

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Elenita Hinds <ecathinds@gmail.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Maxime Jayat <maxime.jayat@mobile-devices.fr>
Signed-off-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 2027 insertions, 0 deletions

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
new file mode 100644
index 000000000000..fe000ea757ea
--- /dev/null
+++ b/net/can/j1939/transport.c
@@ -0,0 +1,2027 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Kurt Van Dijck <kurt.van.dijck@eia.be>
+// Copyright (c) 2018 Protonic,
+//                         Robin van der Gracht <robin@protonic.nl>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Marc Kleine-Budde <kernel@pengutronix.de>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Oleksij Rempel <kernel@pengutronix.de>
+
+#include <linux/can/skb.h>
+
+#include "j1939-priv.h"
+
+#define J1939_XTP_TX_RETRY_LIMIT 100
+
+#define J1939_ETP_PGN_CTL 0xc800
+#define J1939_ETP_PGN_DAT 0xc700
+#define J1939_TP_PGN_CTL 0xec00
+#define J1939_TP_PGN_DAT 0xeb00
+
+#define J1939_TP_CMD_RTS 0x10
+#define J1939_TP_CMD_CTS 0x11
+#define J1939_TP_CMD_EOMA 0x13
+#define J1939_TP_CMD_BAM 0x20
+#define J1939_TP_CMD_ABORT 0xff
+
+#define J1939_ETP_CMD_RTS 0x14
+#define J1939_ETP_CMD_CTS 0x15
+#define J1939_ETP_CMD_DPO 0x16
+#define J1939_ETP_CMD_EOMA 0x17
+#define J1939_ETP_CMD_ABORT 0xff
+
+enum j1939_xtp_abort {
+	J1939_XTP_NO_ABORT = 0,
+	J1939_XTP_ABORT_BUSY = 1,
+	/* Already in one or more connection managed sessions and
+	 * cannot support another.
+	 *
+	 * EALREADY:
+	 * Operation already in progress
+	 */
+
+	J1939_XTP_ABORT_RESOURCE = 2,
+	/* System resources were needed for another task so this
+	 * connection managed session was terminated.
+	 *
+	 * EMSGSIZE:
+	 * The socket type requires that message be sent atomically,
+	 * and the size of the message to be sent made this
+	 * impossible.
+	 */
+
+	J1939_XTP_ABORT_TIMEOUT = 3,
+	/* A timeout occurred and this is the connection abort to
+	 * close the session.
+	 *
+	 * EHOSTUNREACH:
+	 * The destination host cannot be reached (probably because
+	 * the host is down or a remote router cannot reach it).
+	 */
+
+	J1939_XTP_ABORT_GENERIC = 4,
+	/* CTS messages received when data transfer is in progress
+	 *
+	 * EBADMSG:
+	 * Not a data message
+	 */
+
+	J1939_XTP_ABORT_FAULT = 5,
+	/* Maximal retransmit request limit reached
+	 *
+	 * ENOTRECOVERABLE:
+	 * State not recoverable
+	 */
+
+	J1939_XTP_ABORT_UNEXPECTED_DATA = 6,
+	/* Unexpected data transfer packet
+	 *
+	 * ENOTCONN:
+	 * Transport endpoint is not connected
+	 */
+
+	J1939_XTP_ABORT_BAD_SEQ = 7,
+	/* Bad sequence number (and software is not able to recover)
+	 *
+	 * EILSEQ:
+	 * Illegal byte sequence
+	 */
+
+	J1939_XTP_ABORT_DUP_SEQ = 8,
+	/* Duplicate sequence number (and software is not able to
+	 * recover)
+	 */
+
+	J1939_XTP_ABORT_EDPO_UNEXPECTED = 9,
+	/* Unexpected EDPO packet (ETP) or Message size > 1785 bytes
+	 * (TP)
+	 */
+
+	J1939_XTP_ABORT_BAD_EDPO_PGN = 10,
+	/* Unexpected EDPO PGN (PGN in EDPO is bad) */
+
+	J1939_XTP_ABORT_EDPO_OUTOF_CTS = 11,
+	/* EDPO number of packets is greater than CTS */
+
+	J1939_XTP_ABORT_BAD_EDPO_OFFSET = 12,
+	/* Bad EDPO offset */
+
+	J1939_XTP_ABORT_OTHER_DEPRECATED = 13,
+	/* Deprecated. Use 250 instead (Any other reason)  */
+
+	J1939_XTP_ABORT_ECTS_UNXPECTED_PGN = 14,
+	/* Unexpected ECTS PGN (PGN in ECTS is bad) */
+
+	J1939_XTP_ABORT_ECTS_TOO_BIG = 15,
+	/* ECTS requested packets exceeds message size */
+
+	J1939_XTP_ABORT_OTHER = 250,
+	/* Any other reason (if a Connection Abort reason is
+	 * identified that is not listed in the table use code 250)
+	 */
+};
+
+static unsigned int j1939_tp_block = 255;
+static unsigned int j1939_tp_packet_delay;
+static unsigned int j1939_tp_padding = 1;
+
+/* helpers */
+static const char *j1939_xtp_abort_to_str(enum j1939_xtp_abort abort)
+{
+	switch (abort) {
+	case J1939_XTP_ABORT_BUSY:
+		return "Already in one or more connection managed sessions and cannot support another.";
+	case J1939_XTP_ABORT_RESOURCE:
+		return "System resources were needed for another task so this connection managed session was terminated.";
+	case J1939_XTP_ABORT_TIMEOUT:
+		return "A timeout occurred and this is the connection abort to close the session.";
+	case J1939_XTP_ABORT_GENERIC:
+		return "CTS messages received when data transfer is in progress";
+	case J1939_XTP_ABORT_FAULT:
+		return "Maximal retransmit request limit reached";
+	case J1939_XTP_ABORT_UNEXPECTED_DATA:
+		return "Unexpected data transfer packet";
+	case J1939_XTP_ABORT_BAD_SEQ:
+		return "Bad sequence number (and software is not able to recover)";
+	case J1939_XTP_ABORT_DUP_SEQ:
+		return "Duplicate sequence number (and software is not able to recover)";
+	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
+		return "Unexpected EDPO packet (ETP) or Message size > 1785 bytes (TP)";
+	case J1939_XTP_ABORT_BAD_EDPO_PGN:
+		return "Unexpected EDPO PGN (PGN in EDPO is bad)";
+	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
+		return "EDPO number of packets is greater than CTS";
+	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
+		return "Bad EDPO offset";
+	case J1939_XTP_ABORT_OTHER_DEPRECATED:
+		return "Deprecated. Use 250 instead (Any other reason)";
+	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
+		return "Unexpected ECTS PGN (PGN in ECTS is bad)";
+	case J1939_XTP_ABORT_ECTS_TOO_BIG:
+		return "ECTS requested packets exceeds message size";
+	case J1939_XTP_ABORT_OTHER:
+		return "Any other reason (if a Connection Abort reason is identified that is not listed in the table use code 250)";
+	default:
+		return "<unknown>";
+	}
+}
+
+static int j1939_xtp_abort_to_errno(struct j1939_priv *priv,
+				    enum j1939_xtp_abort abort)
+{
+	int err;
+
+	switch (abort) {
+	case J1939_XTP_NO_ABORT:
+		WARN_ON_ONCE(abort == J1939_XTP_NO_ABORT);
+		err = 0;
+		break;
+	case J1939_XTP_ABORT_BUSY:
+		err = EALREADY;
+		break;
+	case J1939_XTP_ABORT_RESOURCE:
+		err = EMSGSIZE;
+		break;
+	case J1939_XTP_ABORT_TIMEOUT:
+		err = EHOSTUNREACH;
+		break;
+	case J1939_XTP_ABORT_GENERIC:
+		err = EBADMSG;
+		break;
+	case J1939_XTP_ABORT_FAULT:
+		err = ENOTRECOVERABLE;
+		break;
+	case J1939_XTP_ABORT_UNEXPECTED_DATA:
+		err = ENOTCONN;
+		break;
+	case J1939_XTP_ABORT_BAD_SEQ:
+		err = EILSEQ;
+		break;
+	case J1939_XTP_ABORT_DUP_SEQ:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_BAD_EDPO_PGN:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_OTHER_DEPRECATED:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_ECTS_TOO_BIG:
+		err = EPROTO;
+		break;
+	case J1939_XTP_ABORT_OTHER:
+		err = EPROTO;
+		break;
+	default:
+		netdev_warn(priv->ndev, "Unknown abort code %i", abort);
+		err = EPROTO;
+	}
+
+	return err;
+}
+
+static inline void j1939_session_list_lock(struct j1939_priv *priv)
+{
+	spin_lock_bh(&priv->active_session_list_lock);
+}
+
+static inline void j1939_session_list_unlock(struct j1939_priv *priv)
+{
+	spin_unlock_bh(&priv->active_session_list_lock);
+}
+
+void j1939_session_get(struct j1939_session *session)
+{
+	kref_get(&session->kref);
+}
+
+/* session completion functions */
+static void __j1939_session_drop(struct j1939_session *session)
+{
+	if (!session->transmission)
+		return;
+
+	j1939_sock_pending_del(session->sk);
+}
+
+static void j1939_session_destroy(struct j1939_session *session)
+{
+	if (session->err)
+		j1939_sk_errqueue(session, J1939_ERRQUEUE_ABORT);
+	else
+		j1939_sk_errqueue(session, J1939_ERRQUEUE_ACK);
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	skb_queue_purge(&session->skb_queue);
+	__j1939_session_drop(session);
+	j1939_priv_put(session->priv);
+	kfree(session);
+}
+
+static void __j1939_session_release(struct kref *kref)
+{
+	struct j1939_session *session = container_of(kref, struct j1939_session,
+						     kref);
+
+	j1939_session_destroy(session);
+}
+
+void j1939_session_put(struct j1939_session *session)
+{
+	kref_put(&session->kref, __j1939_session_release);
+}
+
+static void j1939_session_txtimer_cancel(struct j1939_session *session)
+{
+	if (hrtimer_cancel(&session->txtimer))
+		j1939_session_put(session);
+}
+
+static void j1939_session_rxtimer_cancel(struct j1939_session *session)
+{
+	if (hrtimer_cancel(&session->rxtimer))
+		j1939_session_put(session);
+}
+
+void j1939_session_timers_cancel(struct j1939_session *session)
+{
+	j1939_session_txtimer_cancel(session);
+	j1939_session_rxtimer_cancel(session);
+}
+
+static inline bool j1939_cb_is_broadcast(const struct j1939_sk_buff_cb *skcb)
+{
+	return (!skcb->addr.dst_name && (skcb->addr.da == 0xff));
+}
+
+static void j1939_session_skb_drop_old(struct j1939_session *session)
+{
+	struct sk_buff *do_skb;
+	struct j1939_sk_buff_cb *do_skcb;
+	unsigned int offset_start;
+	unsigned long flags;
+
+	if (skb_queue_len(&session->skb_queue) < 2)
+		return;
+
+	offset_start = session->pkt.tx_acked * 7;
+
+	spin_lock_irqsave(&session->skb_queue.lock, flags);
+	do_skb = skb_peek(&session->skb_queue);
+	do_skcb = j1939_skb_to_cb(do_skb);
+
+	if ((do_skcb->offset + do_skb->len) < offset_start) {
+		__skb_unlink(do_skb, &session->skb_queue);
+		kfree_skb(do_skb);
+	}
+	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
+}
+
+void j1939_session_skb_queue(struct j1939_session *session,
+			     struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_priv *priv = session->priv;
+
+	j1939_ac_fixup(priv, skb);
+
+	if (j1939_address_is_unicast(skcb->addr.da) &&
+	    priv->ents[skcb->addr.da].nusers)
+		skcb->flags |= J1939_ECU_LOCAL_DST;
+
+	skcb->flags |= J1939_ECU_LOCAL_SRC;
+
+	skb_queue_tail(&session->skb_queue, skb);
+}
+
+static struct sk_buff *j1939_session_skb_find(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	struct sk_buff *skb = NULL;
+	struct sk_buff *do_skb;
+	struct j1939_sk_buff_cb *do_skcb;
+	unsigned int offset_start;
+	unsigned long flags;
+
+	offset_start = session->pkt.dpo * 7;
+
+	spin_lock_irqsave(&session->skb_queue.lock, flags);
+	skb_queue_walk(&session->skb_queue, do_skb) {
+		do_skcb = j1939_skb_to_cb(do_skb);
+
+		if (offset_start >= do_skcb->offset &&
+		    offset_start < (do_skcb->offset + do_skb->len)) {
+			skb = do_skb;
+		}
+	}
+	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
+
+	if (!skb)
+		netdev_dbg(priv->ndev, "%s: 0x%p: no skb found for start: %i, queue size: %i\n",
+			   __func__, session, offset_start,
+			   skb_queue_len(&session->skb_queue));
+
+	return skb;
+}
+
+/* see if we are receiver
+ * returns 0 for broadcasts, although we will receive them
+ */
+static inline int j1939_tp_im_receiver(const struct j1939_sk_buff_cb *skcb)
+{
+	return skcb->flags & J1939_ECU_LOCAL_DST;
+}
+
+/* see if we are sender */
+static inline int j1939_tp_im_transmitter(const struct j1939_sk_buff_cb *skcb)
+{
+	return skcb->flags & J1939_ECU_LOCAL_SRC;
+}
+
+/* see if we are involved as either receiver or transmitter */
+static int j1939_tp_im_involved(const struct j1939_sk_buff_cb *skcb, bool swap)
+{
+	if (swap)
+		return j1939_tp_im_receiver(skcb);
+	else
+		return j1939_tp_im_transmitter(skcb);
+}
+
+static int j1939_tp_im_involved_anydir(struct j1939_sk_buff_cb *skcb)
+{
+	return skcb->flags & (J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
+}
+
+/* extract pgn from flow-ctl message */
+static inline pgn_t j1939_xtp_ctl_to_pgn(const u8 *dat)
+{
+	pgn_t pgn;
+
+	pgn = (dat[7] << 16) | (dat[6] << 8) | (dat[5] << 0);
+	if (j1939_pgn_is_pdu1(pgn))
+		pgn &= 0xffff00;
+	return pgn;
+}
+
+static inline unsigned int j1939_tp_ctl_to_size(const u8 *dat)
+{
+	return (dat[2] << 8) + (dat[1] << 0);
+}
+
+static inline unsigned int j1939_etp_ctl_to_packet(const u8 *dat)
+{
+	return (dat[4] << 16) | (dat[3] << 8) | (dat[2] << 0);
+}
+
+static inline unsigned int j1939_etp_ctl_to_size(const u8 *dat)
+{
+	return (dat[4] << 24) | (dat[3] << 16) |
+		(dat[2] << 8) | (dat[1] << 0);
+}
+
+/* find existing session:
+ * reverse: swap cb's src & dst
+ * there is no problem with matching broadcasts, since
+ * broadcasts (no dst, no da) would never call this
+ * with reverse == true
+ */
+static bool j1939_session_match(struct j1939_addr *se_addr,
+				struct j1939_addr *sk_addr, bool reverse)
+{
+	if (se_addr->type != sk_addr->type)
+		return false;
+
+	if (reverse) {
+		if (se_addr->src_name) {
+			if (se_addr->src_name != sk_addr->dst_name)
+				return false;
+		} else if (se_addr->sa != sk_addr->da) {
+			return false;
+		}
+
+		if (se_addr->dst_name) {
+			if (se_addr->dst_name != sk_addr->src_name)
+				return false;
+		} else if (se_addr->da != sk_addr->sa) {
+			return false;
+		}
+	} else {
+		if (se_addr->src_name) {
+			if (se_addr->src_name != sk_addr->src_name)
+				return false;
+		} else if (se_addr->sa != sk_addr->sa) {
+			return false;
+		}
+
+		if (se_addr->dst_name) {
+			if (se_addr->dst_name != sk_addr->dst_name)
+				return false;
+		} else if (se_addr->da != sk_addr->da) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static struct
+j1939_session *j1939_session_get_by_addr_locked(struct j1939_priv *priv,
+						struct list_head *root,
+						struct j1939_addr *addr,
+						bool reverse, bool transmitter)
+{
+	struct j1939_session *session;
+
+	lockdep_assert_held(&priv->active_session_list_lock);
+
+	list_for_each_entry(session, root, active_session_list_entry) {
+		j1939_session_get(session);
+		if (j1939_session_match(&session->skcb.addr, addr, reverse) &&
+		    session->transmission == transmitter)
+			return session;
+		j1939_session_put(session);
+	}
+
+	return NULL;
+}
+
+static struct
+j1939_session *j1939_session_get_simple(struct j1939_priv *priv,
+					struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+
+	lockdep_assert_held(&priv->active_session_list_lock);
+
+	list_for_each_entry(session, &priv->active_session_list,
+			    active_session_list_entry) {
+		j1939_session_get(session);
+		if (session->skcb.addr.type == J1939_SIMPLE &&
+		    session->tskey == skcb->tskey && session->sk == skb->sk)
+			return session;
+		j1939_session_put(session);
+	}
+
+	return NULL;
+}
+
+static struct
+j1939_session *j1939_session_get_by_addr(struct j1939_priv *priv,
+					 struct j1939_addr *addr,
+					 bool reverse, bool transmitter)
+{
+	struct j1939_session *session;
+
+	j1939_session_list_lock(priv);
+	session = j1939_session_get_by_addr_locked(priv,
+						   &priv->active_session_list,
+						   addr, reverse, transmitter);
+	j1939_session_list_unlock(priv);
+
+	return session;
+}
+
+static void j1939_skbcb_swap(struct j1939_sk_buff_cb *skcb)
+{
+	u8 tmp = 0;
+
+	swap(skcb->addr.dst_name, skcb->addr.src_name);
+	swap(skcb->addr.da, skcb->addr.sa);
+
+	/* swap SRC and DST flags, leave other untouched */
+	if (skcb->flags & J1939_ECU_LOCAL_SRC)
+		tmp |= J1939_ECU_LOCAL_DST;
+	if (skcb->flags & J1939_ECU_LOCAL_DST)
+		tmp |= J1939_ECU_LOCAL_SRC;
+	skcb->flags &= ~(J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
+	skcb->flags |= tmp;
+}
+
+static struct
+sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv,
+			     const struct j1939_sk_buff_cb *re_skcb,
+			     bool ctl,
+			     bool swap_src_dst)
+{
+	struct sk_buff *skb;
+	struct j1939_sk_buff_cb *skcb;
+
+	skb = alloc_skb(sizeof(struct can_frame) + sizeof(struct can_skb_priv),
+			GFP_ATOMIC);
+	if (unlikely(!skb))
+		return ERR_PTR(-ENOMEM);
+
+	skb->dev = priv->ndev;
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
+	/* reserve CAN header */
+	skb_reserve(skb, offsetof(struct can_frame, data));
+
+	memcpy(skb->cb, re_skcb, sizeof(skb->cb));
+	skcb = j1939_skb_to_cb(skb);
+	if (swap_src_dst)
+		j1939_skbcb_swap(skcb);
+
+	if (ctl) {
+		if (skcb->addr.type == J1939_ETP)
+			skcb->addr.pgn = J1939_ETP_PGN_CTL;
+		else
+			skcb->addr.pgn = J1939_TP_PGN_CTL;
+	} else {
+		if (skcb->addr.type == J1939_ETP)
+			skcb->addr.pgn = J1939_ETP_PGN_DAT;
+		else
+			skcb->addr.pgn = J1939_TP_PGN_DAT;
+	}
+
+	return skb;
+}
+
+/* TP transmit packet functions */
+static int j1939_tp_tx_dat(struct j1939_session *session,
+			   const u8 *dat, int len)
+{
+	struct j1939_priv *priv = session->priv;
+	struct sk_buff *skb;
+
+	skb = j1939_tp_tx_dat_new(priv, &session->skcb,
+				  false, false);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	skb_put_data(skb, dat, len);
+	if (j1939_tp_padding && len < 8)
+		memset(skb_put(skb, 8 - len), 0xff, 8 - len);
+
+	return j1939_send_one(priv, skb);
+}
+
+static int j1939_xtp_do_tx_ctl(struct j1939_priv *priv,
+			       const struct j1939_sk_buff_cb *re_skcb,
+			       bool swap_src_dst, pgn_t pgn, const u8 *dat)
+{
+	struct sk_buff *skb;
+	u8 *skdat;
+
+	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
+		return 0;
+
+	skb = j1939_tp_tx_dat_new(priv, re_skcb, true, swap_src_dst);
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	skdat = skb_put(skb, 8);
+	memcpy(skdat, dat, 5);
+	skdat[5] = (pgn >> 0);
+	skdat[6] = (pgn >> 8);
+	skdat[7] = (pgn >> 16);
+
+	return j1939_send_one(priv, skb);
+}
+
+static inline int j1939_tp_tx_ctl(struct j1939_session *session,
+				  bool swap_src_dst, const u8 *dat)
+{
+	struct j1939_priv *priv = session->priv;
+
+	return j1939_xtp_do_tx_ctl(priv, &session->skcb,
+				   swap_src_dst,
+				   session->skcb.addr.pgn, dat);
+}
+
+static int j1939_xtp_tx_abort(struct j1939_priv *priv,
+			      const struct j1939_sk_buff_cb *re_skcb,
+			      bool swap_src_dst,
+			      enum j1939_xtp_abort err,
+			      pgn_t pgn)
+{
+	u8 dat[5];
+
+	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
+		return 0;
+
+	memset(dat, 0xff, sizeof(dat));
+	dat[0] = J1939_TP_CMD_ABORT;
+	dat[1] = err;
+	return j1939_xtp_do_tx_ctl(priv, re_skcb, swap_src_dst, pgn, dat);
+}
+
+void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec)
+{
+	j1939_session_get(session);
+	hrtimer_start(&session->txtimer, ms_to_ktime(msec),
+		      HRTIMER_MODE_REL_SOFT);
+}
+
+static inline void j1939_tp_set_rxtimeout(struct j1939_session *session,
+					  int msec)
+{
+	j1939_session_rxtimer_cancel(session);
+	j1939_session_get(session);
+	hrtimer_start(&session->rxtimer, ms_to_ktime(msec),
+		      HRTIMER_MODE_REL_SOFT);
+}
+
+static int j1939_session_tx_rts(struct j1939_session *session)
+{
+	u8 dat[8];
+	int ret;
+
+	memset(dat, 0xff, sizeof(dat));
+
+	dat[1] = (session->total_message_size >> 0);
+	dat[2] = (session->total_message_size >> 8);
+	dat[3] = session->pkt.total;
+
+	if (session->skcb.addr.type == J1939_ETP) {
+		dat[0] = J1939_ETP_CMD_RTS;
+		dat[1] = (session->total_message_size >> 0);
+		dat[2] = (session->total_message_size >> 8);
+		dat[3] = (session->total_message_size >> 16);
+		dat[4] = (session->total_message_size >> 24);
+	} else if (j1939_cb_is_broadcast(&session->skcb)) {
+		dat[0] = J1939_TP_CMD_BAM;
+		/* fake cts for broadcast */
+		session->pkt.tx = 0;
+	} else {
+		dat[0] = J1939_TP_CMD_RTS;
+		dat[4] = dat[3];
+	}
+
+	if (dat[0] == session->last_txcmd)
+		/* done already */
+		return 0;
+
+	ret = j1939_tp_tx_ctl(session, false, dat);
+	if (ret < 0)
+		return ret;
+
+	session->last_txcmd = dat[0];
+	if (dat[0] == J1939_TP_CMD_BAM)
+		j1939_tp_schedule_txtimer(session, 50);
+
+	j1939_tp_set_rxtimeout(session, 1250);
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	return 0;
+}
+
+static int j1939_session_tx_dpo(struct j1939_session *session)
+{
+	unsigned int pkt;
+	u8 dat[8];
+	int ret;
+
+	memset(dat, 0xff, sizeof(dat));
+
+	dat[0] = J1939_ETP_CMD_DPO;
+	session->pkt.dpo = session->pkt.tx_acked;
+	pkt = session->pkt.dpo;
+	dat[1] = session->pkt.last - session->pkt.tx_acked;
+	dat[2] = (pkt >> 0);
+	dat[3] = (pkt >> 8);
+	dat[4] = (pkt >> 16);
+
+	ret = j1939_tp_tx_ctl(session, false, dat);
+	if (ret < 0)
+		return ret;
+
+	session->last_txcmd = dat[0];
+	j1939_tp_set_rxtimeout(session, 1250);
+	session->pkt.tx = session->pkt.tx_acked;
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	return 0;
+}
+
+static int j1939_session_tx_dat(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	struct j1939_sk_buff_cb *skcb;
+	int offset, pkt_done, pkt_end;
+	unsigned int len, pdelay;
+	struct sk_buff *se_skb;
+	const u8 *tpdat;
+	int ret = 0;
+	u8 dat[8];
+
+	se_skb = j1939_session_skb_find(session);
+	if (!se_skb)
+		return -ENOBUFS;
+
+	skcb = j1939_skb_to_cb(se_skb);
+	tpdat = se_skb->data;
+	ret = 0;
+	pkt_done = 0;
+	if (session->skcb.addr.type != J1939_ETP &&
+	    j1939_cb_is_broadcast(&session->skcb))
+		pkt_end = session->pkt.total;
+	else
+		pkt_end = session->pkt.last;
+
+	while (session->pkt.tx < pkt_end) {
+		dat[0] = session->pkt.tx - session->pkt.dpo + 1;
+		offset = (session->pkt.tx * 7) - skcb->offset;
+		len =  se_skb->len - offset;
+		if (len > 7)
+			len = 7;
+
+		memcpy(&dat[1], &tpdat[offset], len);
+		ret = j1939_tp_tx_dat(session, dat, len + 1);
+		if (ret < 0) {
+			/* ENOBUS == CAN interface TX queue is full */
+			if (ret != -ENOBUFS)
+				netdev_alert(priv->ndev,
+					     "%s: 0x%p: queue data error: %i\n",
+					     __func__, session, ret);
+			break;
+		}
+
+		session->last_txcmd = 0xff;
+		pkt_done++;
+		session->pkt.tx++;
+		pdelay = j1939_cb_is_broadcast(&session->skcb) ? 50 :
+			j1939_tp_packet_delay;
+
+		if (session->pkt.tx < session->pkt.total && pdelay) {
+			j1939_tp_schedule_txtimer(session, pdelay);
+			break;
+		}
+	}
+
+	if (pkt_done)
+		j1939_tp_set_rxtimeout(session, 250);
+
+	return ret;
+}
+
+static int j1939_xtp_txnext_transmiter(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	int ret = 0;
+
+	if (!j1939_tp_im_transmitter(&session->skcb)) {
+		netdev_alert(priv->ndev, "%s: 0x%p: called by not transmitter!\n",
+			     __func__, session);
+		return -EINVAL;
+	}
+
+	switch (session->last_cmd) {
+	case 0:
+		ret = j1939_session_tx_rts(session);
+		break;
+
+	case J1939_ETP_CMD_CTS:
+		if (session->last_txcmd != J1939_ETP_CMD_DPO) {
+			ret = j1939_session_tx_dpo(session);
+			if (ret)
+				return ret;
+		}
+
+		/* fall through */
+	case J1939_TP_CMD_CTS:
+	case 0xff: /* did some data */
+	case J1939_ETP_CMD_DPO:
+	case J1939_TP_CMD_BAM:
+		ret = j1939_session_tx_dat(session);
+
+		break;
+	default:
+		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
+			     __func__, session, session->last_cmd);
+	}
+
+	return ret;
+}
+
+static int j1939_session_tx_cts(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	unsigned int pkt, len;
+	int ret;
+	u8 dat[8];
+
+	if (!j1939_sk_recv_match(priv, &session->skcb))
+		return -ENOENT;
+
+	len = session->pkt.total - session->pkt.rx;
+	len = min3(len, session->pkt.block, j1939_tp_block ?: 255);
+	memset(dat, 0xff, sizeof(dat));
+
+	if (session->skcb.addr.type == J1939_ETP) {
+		pkt = session->pkt.rx + 1;
+		dat[0] = J1939_ETP_CMD_CTS;
+		dat[1] = len;
+		dat[2] = (pkt >> 0);
+		dat[3] = (pkt >> 8);
+		dat[4] = (pkt >> 16);
+	} else {
+		dat[0] = J1939_TP_CMD_CTS;
+		dat[1] = len;
+		dat[2] = session->pkt.rx + 1;
+	}
+
+	if (dat[0] == session->last_txcmd)
+		/* done already */
+		return 0;
+
+	ret = j1939_tp_tx_ctl(session, true, dat);
+	if (ret < 0)
+		return ret;
+
+	if (len)
+		/* only mark cts done when len is set */
+		session->last_txcmd = dat[0];
+	j1939_tp_set_rxtimeout(session, 1250);
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	return 0;
+}
+
+static int j1939_session_tx_eoma(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	u8 dat[8];
+	int ret;
+
+	if (!j1939_sk_recv_match(priv, &session->skcb))
+		return -ENOENT;
+
+	memset(dat, 0xff, sizeof(dat));
+
+	if (session->skcb.addr.type == J1939_ETP) {
+		dat[0] = J1939_ETP_CMD_EOMA;
+		dat[1] = session->total_message_size >> 0;
+		dat[2] = session->total_message_size >> 8;
+		dat[3] = session->total_message_size >> 16;
+		dat[4] = session->total_message_size >> 24;
+	} else {
+		dat[0] = J1939_TP_CMD_EOMA;
+		dat[1] = session->total_message_size;
+		dat[2] = session->total_message_size >> 8;
+		dat[3] = session->pkt.total;
+	}
+
+	if (dat[0] == session->last_txcmd)
+		/* done already */
+		return 0;
+
+	ret = j1939_tp_tx_ctl(session, true, dat);
+	if (ret < 0)
+		return ret;
+
+	session->last_txcmd = dat[0];
+
+	/* wait for the EOMA packet to come in */
+	j1939_tp_set_rxtimeout(session, 1250);
+
+	netdev_dbg(session->priv->ndev, "%p: 0x%p\n", __func__, session);
+
+	return 0;
+}
+
+static int j1939_xtp_txnext_receiver(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	int ret = 0;
+
+	if (!j1939_tp_im_receiver(&session->skcb)) {
+		netdev_alert(priv->ndev, "%s: 0x%p: called by not receiver!\n",
+			     __func__, session);
+		return -EINVAL;
+	}
+
+	switch (session->last_cmd) {
+	case J1939_TP_CMD_RTS:
+	case J1939_ETP_CMD_RTS:
+		ret = j1939_session_tx_cts(session);
+		break;
+
+	case J1939_ETP_CMD_CTS:
+	case J1939_TP_CMD_CTS:
+	case 0xff: /* did some data */
+	case J1939_ETP_CMD_DPO:
+		if ((session->skcb.addr.type == J1939_TP &&
+		     j1939_cb_is_broadcast(&session->skcb)))
+			break;
+
+		if (session->pkt.rx >= session->pkt.total) {
+			ret = j1939_session_tx_eoma(session);
+		} else if (session->pkt.rx >= session->pkt.last) {
+			session->last_txcmd = 0;
+			ret = j1939_session_tx_cts(session);
+		}
+		break;
+	default:
+		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
+			     __func__, session, session->last_cmd);
+	}
+
+	return ret;
+}
+
+static int j1939_simple_txnext(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	struct sk_buff *se_skb = j1939_session_skb_find(session);
+	struct sk_buff *skb;
+	int ret;
+
+	if (!se_skb)
+		return 0;
+
+	skb = skb_clone(se_skb, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	can_skb_set_owner(skb, se_skb->sk);
+
+	j1939_tp_set_rxtimeout(session, J1939_SIMPLE_ECHO_TIMEOUT_MS);
+
+	ret = j1939_send_one(priv, skb);
+	if (ret)
+		return ret;
+
+	j1939_sk_errqueue(session, J1939_ERRQUEUE_SCHED);
+	j1939_sk_queue_activate_next(session);
+
+	return 0;
+}
+
+static bool j1939_session_deactivate_locked(struct j1939_session *session)
+{
+	bool active = false;
+
+	lockdep_assert_held(&session->priv->active_session_list_lock);
+
+	if (session->state >= J1939_SESSION_ACTIVE &&
+	    session->state < J1939_SESSION_ACTIVE_MAX) {
+		active = true;
+
+		list_del_init(&session->active_session_list_entry);
+		session->state = J1939_SESSION_DONE;
+		j1939_session_put(session);
+	}
+
+	return active;
+}
+
+static bool j1939_session_deactivate(struct j1939_session *session)
+{
+	bool active;
+
+	j1939_session_list_lock(session->priv);
+	active = j1939_session_deactivate_locked(session);
+	j1939_session_list_unlock(session->priv);
+
+	return active;
+}
+
+static void
+j1939_session_deactivate_activate_next(struct j1939_session *session)
+{
+	if (j1939_session_deactivate(session))
+		j1939_sk_queue_activate_next(session);
+}
+
+static void j1939_session_cancel(struct j1939_session *session,
+				 enum j1939_xtp_abort err)
+{
+	struct j1939_priv *priv = session->priv;
+
+	WARN_ON_ONCE(!err);
+
+	session->err = j1939_xtp_abort_to_errno(priv, err);
+	/* do not send aborts on incoming broadcasts */
+	if (!j1939_cb_is_broadcast(&session->skcb)) {
+		session->state = J1939_SESSION_WAITING_ABORT;
+		j1939_xtp_tx_abort(priv, &session->skcb,
+				   !session->transmission,
+				   err, session->skcb.addr.pgn);
+	}
+
+	if (session->sk)
+		j1939_sk_send_loop_abort(session->sk, session->err);
+}
+
+static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
+{
+	struct j1939_session *session =
+		container_of(hrtimer, struct j1939_session, txtimer);
+	struct j1939_priv *priv = session->priv;
+	int ret = 0;
+
+	if (session->skcb.addr.type == J1939_SIMPLE) {
+		ret = j1939_simple_txnext(session);
+	} else {
+		if (session->transmission)
+			ret = j1939_xtp_txnext_transmiter(session);
+		else
+			ret = j1939_xtp_txnext_receiver(session);
+	}
+
+	switch (ret) {
+	case -ENOBUFS:
+		/* Retry limit is currently arbitrary chosen */
+		if (session->tx_retry < J1939_XTP_TX_RETRY_LIMIT) {
+			session->tx_retry++;
+			j1939_tp_schedule_txtimer(session,
+						  10 + prandom_u32_max(16));
+		} else {
+			netdev_alert(priv->ndev, "%s: 0x%p: tx retry count reached\n",
+				     __func__, session);
+			session->err = -ENETUNREACH;
+			j1939_session_rxtimer_cancel(session);
+			j1939_session_deactivate_activate_next(session);
+		}
+		break;
+	case -ENETDOWN:
+		/* In this case we should get a netdev_event(), all active
+		 * sessions will be cleared by
+		 * j1939_cancel_all_active_sessions(). So handle this as an
+		 * error, but let j1939_cancel_all_active_sessions() do the
+		 * cleanup including propagation of the error to user space.
+		 */
+		break;
+	case 0:
+		session->tx_retry = 0;
+		break;
+	default:
+		netdev_alert(priv->ndev, "%s: 0x%p: tx aborted with unknown reason: %i\n",
+			     __func__, session, ret);
+		if (session->skcb.addr.type != J1939_SIMPLE) {
+			j1939_tp_set_rxtimeout(session,
+					       J1939_XTP_ABORT_TIMEOUT_MS);
+			j1939_session_cancel(session, J1939_XTP_ABORT_OTHER);
+		} else {
+			session->err = ret;
+			j1939_session_rxtimer_cancel(session);
+			j1939_session_deactivate_activate_next(session);
+		}
+	}
+
+	j1939_session_put(session);
+
+	return HRTIMER_NORESTART;
+}
+
+static void j1939_session_completed(struct j1939_session *session)
+{
+	struct sk_buff *skb;
+
+	if (!session->transmission) {
+		skb = j1939_session_skb_find(session);
+		/* distribute among j1939 receivers */
+		j1939_sk_recv(session->priv, skb);
+	}
+
+	j1939_session_deactivate_activate_next(session);
+}
+
+static enum hrtimer_restart j1939_tp_rxtimer(struct hrtimer *hrtimer)
+{
+	struct j1939_session *session = container_of(hrtimer,
+						     struct j1939_session,
+						     rxtimer);
+	struct j1939_priv *priv = session->priv;
+
+	if (session->state == J1939_SESSION_WAITING_ABORT) {
+		netdev_alert(priv->ndev, "%s: 0x%p: abort rx timeout. Force session deactivation\n",
+			     __func__, session);
+
+		j1939_session_deactivate_activate_next(session);
+
+	} else if (session->skcb.addr.type == J1939_SIMPLE) {
+		netdev_alert(priv->ndev, "%s: 0x%p: Timeout. Failed to send simple message.\n",
+			     __func__, session);
+
+		/* The message is probably stuck in the CAN controller and can
+		 * be send as soon as CAN bus is in working state again.
+		 */
+		session->err = -ETIME;
+		j1939_session_deactivate(session);
+	} else {
+		netdev_alert(priv->ndev, "%s: 0x%p: rx timeout, send abort\n",
+			     __func__, session);
+
+		j1939_session_list_lock(session->priv);
+		if (session->state >= J1939_SESSION_ACTIVE &&
+		    session->state < J1939_SESSION_ACTIVE_MAX) {
+			j1939_session_get(session);
+			hrtimer_start(&session->rxtimer,
+				      ms_to_ktime(J1939_XTP_ABORT_TIMEOUT_MS),
+				      HRTIMER_MODE_REL_SOFT);
+			j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
+		}
+		j1939_session_list_unlock(session->priv);
+	}
+
+	j1939_session_put(session);
+
+	return HRTIMER_NORESTART;
+}
+
+static bool j1939_xtp_rx_cmd_bad_pgn(struct j1939_session *session,
+				     const struct sk_buff *skb)
+{
+	const struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	pgn_t pgn = j1939_xtp_ctl_to_pgn(skb->data);
+	struct j1939_priv *priv = session->priv;
+	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
+	u8 cmd = skb->data[0];
+
+	if (session->skcb.addr.pgn == pgn)
+		return false;
+
+	switch (cmd) {
+	case J1939_TP_CMD_BAM:
+		abort = J1939_XTP_NO_ABORT;
+		break;
+
+	case J1939_ETP_CMD_RTS:
+	case J1939_TP_CMD_RTS: /* fall through */
+		abort = J1939_XTP_ABORT_BUSY;
+		break;
+
+	case J1939_ETP_CMD_CTS:
+	case J1939_TP_CMD_CTS: /* fall through */
+		abort = J1939_XTP_ABORT_ECTS_UNXPECTED_PGN;
+		break;
+
+	case J1939_ETP_CMD_DPO:
+		abort = J1939_XTP_ABORT_BAD_EDPO_PGN;
+		break;
+
+	case J1939_ETP_CMD_EOMA:
+	case J1939_TP_CMD_EOMA: /* fall through */
+		abort = J1939_XTP_ABORT_OTHER;
+		break;
+
+	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
+		abort = J1939_XTP_NO_ABORT;
+		break;
+
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	netdev_warn(priv->ndev, "%s: 0x%p: CMD 0x%02x with PGN 0x%05x for running session with different PGN 0x%05x.\n",
+		    __func__, session, cmd, pgn, session->skcb.addr.pgn);
+	if (abort != J1939_XTP_NO_ABORT)
+		j1939_xtp_tx_abort(priv, skcb, true, abort, pgn);
+
+	return true;
+}
+
+static void j1939_xtp_rx_abort_one(struct j1939_priv *priv, struct sk_buff *skb,
+				   bool reverse, bool transmitter)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+	u8 abort = skb->data[1];
+
+	session = j1939_session_get_by_addr(priv, &skcb->addr, reverse,
+					    transmitter);
+	if (!session)
+		return;
+
+	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
+		goto abort_put;
+
+	netdev_info(priv->ndev, "%s: 0x%p: 0x%05x: (%u) %s\n", __func__,
+		    session, j1939_xtp_ctl_to_pgn(skb->data), abort,
+		    j1939_xtp_abort_to_str(abort));
+
+	j1939_session_timers_cancel(session);
+	session->err = j1939_xtp_abort_to_errno(priv, abort);
+	if (session->sk)
+		j1939_sk_send_loop_abort(session->sk, session->err);
+	j1939_session_deactivate_activate_next(session);
+
+abort_put:
+	j1939_session_put(session);
+}
+
+/* abort packets may come in 2 directions */
+static void
+j1939_xtp_rx_abort(struct j1939_priv *priv, struct sk_buff *skb,
+		   bool transmitter)
+{
+	j1939_xtp_rx_abort_one(priv, skb, false, transmitter);
+	j1939_xtp_rx_abort_one(priv, skb, true, transmitter);
+}
+
+static void
+j1939_xtp_rx_eoma_one(struct j1939_session *session, struct sk_buff *skb)
+{
+	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
+		return;
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	session->pkt.tx_acked = session->pkt.total;
+	j1939_session_timers_cancel(session);
+	/* transmitted without problems */
+	j1939_session_completed(session);
+}
+
+static void
+j1939_xtp_rx_eoma(struct j1939_priv *priv, struct sk_buff *skb,
+		  bool transmitter)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+
+	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
+					    transmitter);
+	if (!session)
+		return;
+
+	j1939_xtp_rx_eoma_one(session, skb);
+	j1939_session_put(session);
+}
+
+static void
+j1939_xtp_rx_cts_one(struct j1939_session *session, struct sk_buff *skb)
+{
+	enum j1939_xtp_abort err = J1939_XTP_ABORT_FAULT;
+	unsigned int pkt;
+	const u8 *dat;
+
+	dat = skb->data;
+
+	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
+		return;
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	if (session->last_cmd == dat[0]) {
+		err = J1939_XTP_ABORT_DUP_SEQ;
+		goto out_session_cancel;
+	}
+
+	if (session->skcb.addr.type == J1939_ETP)
+		pkt = j1939_etp_ctl_to_packet(dat);
+	else
+		pkt = dat[2];
+
+	if (!pkt)
+		goto out_session_cancel;
+	else if (dat[1] > session->pkt.block /* 0xff for etp */)
+		goto out_session_cancel;
+
+	/* set packet counters only when not CTS(0) */
+	session->pkt.tx_acked = pkt - 1;
+	j1939_session_skb_drop_old(session);
+	session->pkt.last = session->pkt.tx_acked + dat[1];
+	if (session->pkt.last > session->pkt.total)
+		/* safety measure */
+		session->pkt.last = session->pkt.total;
+	/* TODO: do not set tx here, do it in txtimer */
+	session->pkt.tx = session->pkt.tx_acked;
+
+	session->last_cmd = dat[0];
+	if (dat[1]) {
+		j1939_tp_set_rxtimeout(session, 1250);
+		if (session->transmission) {
+			if (session->pkt.tx_acked)
+				j1939_sk_errqueue(session,
+						  J1939_ERRQUEUE_SCHED);
+			j1939_session_txtimer_cancel(session);
+			j1939_tp_schedule_txtimer(session, 0);
+		}
+	} else {
+		/* CTS(0) */
+		j1939_tp_set_rxtimeout(session, 550);
+	}
+	return;
+
+ out_session_cancel:
+	j1939_session_timers_cancel(session);
+	j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
+	j1939_session_cancel(session, err);
+}
+
+static void
+j1939_xtp_rx_cts(struct j1939_priv *priv, struct sk_buff *skb, bool transmitter)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+
+	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
+					    transmitter);
+	if (!session)
+		return;
+	j1939_xtp_rx_cts_one(session, skb);
+	j1939_session_put(session);
+}
+
+static struct j1939_session *j1939_session_new(struct j1939_priv *priv,
+					       struct sk_buff *skb, size_t size)
+{
+	struct j1939_session *session;
+	struct j1939_sk_buff_cb *skcb;
+
+	session = kzalloc(sizeof(*session), gfp_any());
+	if (!session)
+		return NULL;
+
+	INIT_LIST_HEAD(&session->active_session_list_entry);
+	INIT_LIST_HEAD(&session->sk_session_queue_entry);
+	kref_init(&session->kref);
+
+	j1939_priv_get(priv);
+	session->priv = priv;
+	session->total_message_size = size;
+	session->state = J1939_SESSION_NEW;
+
+	skb_queue_head_init(&session->skb_queue);
+	skb_queue_tail(&session->skb_queue, skb);
+
+	skcb = j1939_skb_to_cb(skb);
+	memcpy(&session->skcb, skcb, sizeof(session->skcb));
+
+	hrtimer_init(&session->txtimer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL_SOFT);
+	session->txtimer.function = j1939_tp_txtimer;
+	hrtimer_init(&session->rxtimer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL_SOFT);
+	session->rxtimer.function = j1939_tp_rxtimer;
+
+	netdev_dbg(priv->ndev, "%s: 0x%p: sa: %02x, da: %02x\n",
+		   __func__, session, skcb->addr.sa, skcb->addr.da);
+
+	return session;
+}
+
+static struct
+j1939_session *j1939_session_fresh_new(struct j1939_priv *priv,
+				       int size,
+				       const struct j1939_sk_buff_cb *rel_skcb)
+{
+	struct sk_buff *skb;
+	struct j1939_sk_buff_cb *skcb;
+	struct j1939_session *session;
+
+	skb = alloc_skb(size + sizeof(struct can_skb_priv), GFP_ATOMIC);
+	if (unlikely(!skb))
+		return NULL;
+
+	skb->dev = priv->ndev;
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
+	skcb = j1939_skb_to_cb(skb);
+	memcpy(skcb, rel_skcb, sizeof(*skcb));
+
+	session = j1939_session_new(priv, skb, skb->len);
+	if (!session) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	/* alloc data area */
+	skb_put(skb, size);
+	/* skb is recounted in j1939_session_new() */
+	return session;
+}
+
+int j1939_session_activate(struct j1939_session *session)
+{
+	struct j1939_priv *priv = session->priv;
+	struct j1939_session *active = NULL;
+	int ret = 0;
+
+	j1939_session_list_lock(priv);
+	if (session->skcb.addr.type != J1939_SIMPLE)
+		active = j1939_session_get_by_addr_locked(priv,
+							  &priv->active_session_list,
+							  &session->skcb.addr, false,
+							  session->transmission);
+	if (active) {
+		j1939_session_put(active);
+		ret = -EAGAIN;
+	} else {
+		WARN_ON_ONCE(session->state != J1939_SESSION_NEW);
+		list_add_tail(&session->active_session_list_entry,
+			      &priv->active_session_list);
+		j1939_session_get(session);
+		session->state = J1939_SESSION_ACTIVE;
+
+		netdev_dbg(session->priv->ndev, "%s: 0x%p\n",
+			   __func__, session);
+	}
+	j1939_session_list_unlock(priv);
+
+	return ret;
+}
+
+static struct
+j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
+					    struct sk_buff *skb)
+{
+	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
+	struct j1939_sk_buff_cb skcb = *j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+	const u8 *dat;
+	pgn_t pgn;
+	int len;
+
+	netdev_dbg(priv->ndev, "%s\n", __func__);
+
+	dat = skb->data;
+	pgn = j1939_xtp_ctl_to_pgn(dat);
+	skcb.addr.pgn = pgn;
+
+	if (!j1939_sk_recv_match(priv, &skcb))
+		return NULL;
+
+	if (skcb.addr.type == J1939_ETP) {
+		len = j1939_etp_ctl_to_size(dat);
+		if (len > J1939_MAX_ETP_PACKET_SIZE)
+			abort = J1939_XTP_ABORT_FAULT;
+		else if (len > priv->tp_max_packet_size)
+			abort = J1939_XTP_ABORT_RESOURCE;
+		else if (len <= J1939_MAX_TP_PACKET_SIZE)
+			abort = J1939_XTP_ABORT_FAULT;
+	} else {
+		len = j1939_tp_ctl_to_size(dat);
+		if (len > J1939_MAX_TP_PACKET_SIZE)
+			abort = J1939_XTP_ABORT_FAULT;
+		else if (len > priv->tp_max_packet_size)
+			abort = J1939_XTP_ABORT_RESOURCE;
+	}
+
+	if (abort != J1939_XTP_NO_ABORT) {
+		j1939_xtp_tx_abort(priv, &skcb, true, abort, pgn);
+		return NULL;
+	}
+
+	session = j1939_session_fresh_new(priv, len, &skcb);
+	if (!session) {
+		j1939_xtp_tx_abort(priv, &skcb, true,
+				   J1939_XTP_ABORT_RESOURCE, pgn);
+		return NULL;
+	}
+
+	/* initialize the control buffer: plain copy */
+	session->pkt.total = (len + 6) / 7;
+	session->pkt.block = 0xff;
+	if (skcb.addr.type != J1939_ETP) {
+		if (dat[3] != session->pkt.total)
+			netdev_alert(priv->ndev, "%s: 0x%p: strange total, %u != %u\n",
+				     __func__, session, session->pkt.total,
+				     dat[3]);
+		session->pkt.total = dat[3];
+		session->pkt.block = min(dat[3], dat[4]);
+	}
+
+	session->pkt.rx = 0;
+	session->pkt.tx = 0;
+
+	WARN_ON_ONCE(j1939_session_activate(session));
+
+	return session;
+}
+
+static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
+					   struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_priv *priv = session->priv;
+
+	if (!session->transmission) {
+		if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
+			return -EBUSY;
+
+		/* RTS on active session */
+		j1939_session_timers_cancel(session);
+		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
+		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
+	}
+
+	if (session->last_cmd != 0) {
+		/* we received a second rts on the same connection */
+		netdev_alert(priv->ndev, "%s: 0x%p: connection exists (%02x %02x). last cmd: %x\n",
+			     __func__, session, skcb->addr.sa, skcb->addr.da,
+			     session->last_cmd);
+
+		j1939_session_timers_cancel(session);
+		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
+		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
+
+		return -EBUSY;
+	}
+
+	if (session->skcb.addr.sa != skcb->addr.sa ||
+	    session->skcb.addr.da != skcb->addr.da)
+		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",
+			    __func__, session,
+			    session->skcb.addr.sa, skcb->addr.sa,
+			    session->skcb.addr.da, skcb->addr.da);
+	/* make sure 'sa' & 'da' are correct !
+	 * They may be 'not filled in yet' for sending
+	 * skb's, since they did not pass the Address Claim ever.
+	 */
+	session->skcb.addr.sa = skcb->addr.sa;
+	session->skcb.addr.da = skcb->addr.da;
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	return 0;
+}
+
+static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
+			     bool transmitter)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+	u8 cmd = skb->data[0];
+
+	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
+					    transmitter);
+
+	if (!session) {
+		if (transmitter) {
+			/* If we're the transmitter and this function is called,
+			 * we received our own RTS. A session has already been
+			 * created.
+			 *
+			 * For some reasons however it might have been destroyed
+			 * already. So don't create a new one here (using
+			 * "j1939_xtp_rx_rts_session_new()") as this will be a
+			 * receiver session.
+			 *
+			 * The reasons the session is already destroyed might
+			 * be:
+			 * - user space closed socket was and the session was
+			 *   aborted
+			 * - session was aborted due to external abort message
+			 */
+			return;
+		}
+		session = j1939_xtp_rx_rts_session_new(priv, skb);
+		if (!session)
+			return;
+	} else {
+		if (j1939_xtp_rx_rts_session_active(session, skb)) {
+			j1939_session_put(session);
+			return;
+		}
+	}
+	session->last_cmd = cmd;
+
+	j1939_tp_set_rxtimeout(session, 1250);
+
+	if (cmd != J1939_TP_CMD_BAM && !session->transmission) {
+		j1939_session_txtimer_cancel(session);
+		j1939_tp_schedule_txtimer(session, 0);
+	}
+
+	j1939_session_put(session);
+}
+
+static void j1939_xtp_rx_dpo_one(struct j1939_session *session,
+				 struct sk_buff *skb)
+{
+	const u8 *dat = skb->data;
+
+	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
+		return;
+
+	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
+
+	/* transmitted without problems */
+	session->pkt.dpo = j1939_etp_ctl_to_packet(skb->data);
+	session->last_cmd = dat[0];
+	j1939_tp_set_rxtimeout(session, 750);
+}
+
+static void j1939_xtp_rx_dpo(struct j1939_priv *priv, struct sk_buff *skb,
+			     bool transmitter)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+
+	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
+					    transmitter);
+	if (!session) {
+		netdev_info(priv->ndev,
+			    "%s: no connection found\n", __func__);
+		return;
+	}
+
+	j1939_xtp_rx_dpo_one(session, skb);
+	j1939_session_put(session);
+}
+
+static void j1939_xtp_rx_dat_one(struct j1939_session *session,
+				 struct sk_buff *skb)
+{
+	struct j1939_priv *priv = session->priv;
+	struct j1939_sk_buff_cb *skcb;
+	struct sk_buff *se_skb;
+	const u8 *dat;
+	u8 *tpdat;
+	int offset;
+	int nbytes;
+	bool final = false;
+	bool do_cts_eoma = false;
+	int packet;
+
+	skcb = j1939_skb_to_cb(skb);
+	dat = skb->data;
+	if (skb->len <= 1)
+		/* makes no sense */
+		goto out_session_cancel;
+
+	switch (session->last_cmd) {
+	case 0xff:
+		break;
+	case J1939_ETP_CMD_DPO:
+		if (skcb->addr.type == J1939_ETP)
+			break;
+		/* fall through */
+	case J1939_TP_CMD_BAM: /* fall through */
+	case J1939_TP_CMD_CTS: /* fall through */
+		if (skcb->addr.type != J1939_ETP)
+			break;
+		/* fall through */
+	default:
+		netdev_info(priv->ndev, "%s: 0x%p: last %02x\n", __func__,
+			    session, session->last_cmd);
+		goto out_session_cancel;
+	}
+
+	packet = (dat[0] - 1 + session->pkt.dpo);
+	if (packet > session->pkt.total ||
+	    (session->pkt.rx + 1) > session->pkt.total) {
+		netdev_info(priv->ndev, "%s: 0x%p: should have been completed\n",
+			    __func__, session);
+		goto out_session_cancel;
+	}
+	se_skb = j1939_session_skb_find(session);
+	if (!se_skb) {
+		netdev_warn(priv->ndev, "%s: 0x%p: no skb found\n", __func__,
+			    session);
+		goto out_session_cancel;
+	}
+
+	skcb = j1939_skb_to_cb(se_skb);
+	offset = packet * 7 - skcb->offset;
+	nbytes = se_skb->len - offset;
+	if (nbytes > 7)
+		nbytes = 7;
+	if (nbytes <= 0 || (nbytes + 1) > skb->len) {
+		netdev_info(priv->ndev, "%s: 0x%p: nbytes %i, len %i\n",
+			    __func__, session, nbytes, skb->len);
+		goto out_session_cancel;
+	}
+
+	tpdat = se_skb->data;
+	memcpy(&tpdat[offset], &dat[1], nbytes);
+	if (packet == session->pkt.rx)
+		session->pkt.rx++;
+
+	if (skcb->addr.type != J1939_ETP &&
+	    j1939_cb_is_broadcast(&session->skcb)) {
+		if (session->pkt.rx >= session->pkt.total)
+			final = true;
+	} else {
+		/* never final, an EOMA must follow */
+		if (session->pkt.rx >= session->pkt.last)
+			do_cts_eoma = true;
+	}
+
+	if (final) {
+		j1939_session_completed(session);
+	} else if (do_cts_eoma) {
+		j1939_tp_set_rxtimeout(session, 1250);
+		if (!session->transmission)
+			j1939_tp_schedule_txtimer(session, 0);
+	} else {
+		j1939_tp_set_rxtimeout(session, 250);
+	}
+	session->last_cmd = 0xff;
+	j1939_session_put(session);
+
+	return;
+
+ out_session_cancel:
+	j1939_session_timers_cancel(session);
+	j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
+	j1939_session_cancel(session, J1939_XTP_ABORT_FAULT);
+	j1939_session_put(session);
+}
+
+static void j1939_xtp_rx_dat(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb;
+	struct j1939_session *session;
+
+	skcb = j1939_skb_to_cb(skb);
+
+	if (j1939_tp_im_transmitter(skcb)) {
+		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
+						    true);
+		if (!session)
+			netdev_info(priv->ndev, "%s: no tx connection found\n",
+				    __func__);
+		else
+			j1939_xtp_rx_dat_one(session, skb);
+	}
+
+	if (j1939_tp_im_receiver(skcb)) {
+		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
+						    false);
+		if (!session)
+			netdev_info(priv->ndev, "%s: no rx connection found\n",
+				    __func__);
+		else
+			j1939_xtp_rx_dat_one(session, skb);
+	}
+}
+
+/* j1939 main intf */
+struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
+				    struct sk_buff *skb, size_t size)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_session *session;
+	int ret;
+
+	if (skcb->addr.pgn == J1939_TP_PGN_DAT ||
+	    skcb->addr.pgn == J1939_TP_PGN_CTL ||
+	    skcb->addr.pgn == J1939_ETP_PGN_DAT ||
+	    skcb->addr.pgn == J1939_ETP_PGN_CTL)
+		/* avoid conflict */
+		return ERR_PTR(-EDOM);
+
+	if (size > priv->tp_max_packet_size)
+		return ERR_PTR(-EMSGSIZE);
+
+	if (size <= 8)
+		skcb->addr.type = J1939_SIMPLE;
+	else if (size > J1939_MAX_TP_PACKET_SIZE)
+		skcb->addr.type = J1939_ETP;
+	else
+		skcb->addr.type = J1939_TP;
+
+	if (skcb->addr.type == J1939_ETP &&
+	    j1939_cb_is_broadcast(skcb))
+		return ERR_PTR(-EDESTADDRREQ);
+
+	/* fill in addresses from names */
+	ret = j1939_ac_fixup(priv, skb);
+	if (unlikely(ret))
+		return ERR_PTR(ret);
+
+	/* fix DST flags, it may be used there soon */
+	if (j1939_address_is_unicast(skcb->addr.da) &&
+	    priv->ents[skcb->addr.da].nusers)
+		skcb->flags |= J1939_ECU_LOCAL_DST;
+
+	/* src is always local, I'm sending ... */
+	skcb->flags |= J1939_ECU_LOCAL_SRC;
+
+	/* prepare new session */
+	session = j1939_session_new(priv, skb, size);
+	if (!session)
+		return ERR_PTR(-ENOMEM);
+
+	/* skb is recounted in j1939_session_new() */
+	session->sk = skb->sk;
+	session->transmission = true;
+	session->pkt.total = (size + 6) / 7;
+	session->pkt.block = skcb->addr.type == J1939_ETP ? 255 :
+		min(j1939_tp_block ?: 255, session->pkt.total);
+
+	if (j1939_cb_is_broadcast(&session->skcb))
+		/* set the end-packet for broadcast */
+		session->pkt.last = session->pkt.total;
+
+	skcb->tskey = session->sk->sk_tskey++;
+	session->tskey = skcb->tskey;
+
+	return session;
+}
+
+static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	int extd = J1939_TP;
+	u8 cmd = skb->data[0];
+
+	switch (cmd) {
+	case J1939_ETP_CMD_RTS:
+		extd = J1939_ETP;
+		/* fall through */
+	case J1939_TP_CMD_BAM: /* fall through */
+	case J1939_TP_CMD_RTS: /* fall through */
+		if (skcb->addr.type != extd)
+			return;
+
+		if (cmd == J1939_TP_CMD_RTS && j1939_cb_is_broadcast(skcb)) {
+			netdev_alert(priv->ndev, "%s: rts without destination (%02x)\n",
+				     __func__, skcb->addr.sa);
+			return;
+		}
+
+		if (j1939_tp_im_transmitter(skcb))
+			j1939_xtp_rx_rts(priv, skb, true);
+
+		if (j1939_tp_im_receiver(skcb))
+			j1939_xtp_rx_rts(priv, skb, false);
+
+		break;
+
+	case J1939_ETP_CMD_CTS:
+		extd = J1939_ETP;
+		/* fall through */
+	case J1939_TP_CMD_CTS:
+		if (skcb->addr.type != extd)
+			return;
+
+		if (j1939_tp_im_transmitter(skcb))
+			j1939_xtp_rx_cts(priv, skb, false);
+
+		if (j1939_tp_im_receiver(skcb))
+			j1939_xtp_rx_cts(priv, skb, true);
+
+		break;
+
+	case J1939_ETP_CMD_DPO:
+		if (skcb->addr.type != J1939_ETP)
+			return;
+
+		if (j1939_tp_im_transmitter(skcb))
+			j1939_xtp_rx_dpo(priv, skb, true);
+
+		if (j1939_tp_im_receiver(skcb))
+			j1939_xtp_rx_dpo(priv, skb, false);
+
+		break;
+
+	case J1939_ETP_CMD_EOMA:
+		extd = J1939_ETP;
+		/* fall through */
+	case J1939_TP_CMD_EOMA:
+		if (skcb->addr.type != extd)
+			return;
+
+		if (j1939_tp_im_transmitter(skcb))
+			j1939_xtp_rx_eoma(priv, skb, false);
+
+		if (j1939_tp_im_receiver(skcb))
+			j1939_xtp_rx_eoma(priv, skb, true);
+
+		break;
+
+	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
+		if (j1939_tp_im_transmitter(skcb))
+			j1939_xtp_rx_abort(priv, skb, true);
+
+		if (j1939_tp_im_receiver(skcb))
+			j1939_xtp_rx_abort(priv, skb, false);
+
+		break;
+	default:
+		return;
+	}
+}
+
+int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+
+	if (!j1939_tp_im_involved_anydir(skcb))
+		return 0;
+
+	switch (skcb->addr.pgn) {
+	case J1939_ETP_PGN_DAT:
+		skcb->addr.type = J1939_ETP;
+		/* fall through */
+	case J1939_TP_PGN_DAT:
+		j1939_xtp_rx_dat(priv, skb);
+		break;
+
+	case J1939_ETP_PGN_CTL:
+		skcb->addr.type = J1939_ETP;
+		/* fall through */
+	case J1939_TP_PGN_CTL:
+		if (skb->len < 8)
+			return 0; /* Don't care. Nothing to extract here */
+
+		j1939_tp_cmd_recv(priv, skb);
+		break;
+	default:
+		return 0; /* no problem */
+	}
+	return 1; /* "I processed the message" */
+}
+
+void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_session *session;
+
+	if (!skb->sk)
+		return;
+
+	j1939_session_list_lock(priv);
+	session = j1939_session_get_simple(priv, skb);
+	j1939_session_list_unlock(priv);
+	if (!session) {
+		netdev_warn(priv->ndev,
+			    "%s: Received already invalidated message\n",
+			    __func__);
+		return;
+	}
+
+	j1939_session_timers_cancel(session);
+	j1939_session_deactivate(session);
+	j1939_session_put(session);
+}
+
+int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk)
+{
+	struct j1939_session *session, *saved;
+
+	netdev_dbg(priv->ndev, "%s, sk: %p\n", __func__, sk);
+	j1939_session_list_lock(priv);
+	list_for_each_entry_safe(session, saved,
+				 &priv->active_session_list,
+				 active_session_list_entry) {
+		if (!sk || sk == session->sk) {
+			j1939_session_timers_cancel(session);
+			session->err = ESHUTDOWN;
+			j1939_session_deactivate_locked(session);
+		}
+	}
+	j1939_session_list_unlock(priv);
+	return NOTIFY_DONE;
+}
+
+void j1939_tp_init(struct j1939_priv *priv)
+{
+	spin_lock_init(&priv->active_session_list_lock);
+	INIT_LIST_HEAD(&priv->active_session_list);
+	priv->tp_max_packet_size = J1939_MAX_ETP_PACKET_SIZE;
+}