Resguardo inicial

linux-7.2.3/net/can/j1939/Kconfig

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# SAE J1939 network layer core configuration
+#
+
+config CAN_J1939
+	tristate "SAE J1939"
+	depends on CAN
+	help
+	  SAE J1939
+	  Say Y to have in-kernel support for j1939 socket type. This
+	  allows communication according to SAE j1939.
+	  The relevant parts in kernel are
+	  SAE j1939-21 (datalink & transport protocol)
+	  & SAE j1939-81 (network management).

linux-7.2.3/net/can/j1939/Makefile

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_CAN_J1939) += can-j1939.o
+
+can-j1939-objs := \
+	address-claim.o \
+	bus.o \
+	main.o \
+	socket.o \
+	transport.o

linux-7.2.3/net/can/j1939/address-claim.c

@@ -0,0 +1,270 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Kurt Van Dijck <kurt.van.dijck@eia.be>
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Pieter Beyens <pieter.beyens@eia.be>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Marc Kleine-Budde <kernel@pengutronix.de>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Oleksij Rempel <kernel@pengutronix.de>
+
+/* J1939 Address Claiming.
+ * Address Claiming in the kernel
+ * - keeps track of the AC states of ECU's,
+ * - resolves NAME<=>SA taking into account the AC states of ECU's.
+ *
+ * All Address Claim msgs (including host-originated msg) are processed
+ * at the receive path (a sent msg is always received again via CAN echo).
+ * As such, the processing of AC msgs is done in the order on which msgs
+ * are sent on the bus.
+ *
+ * This module doesn't send msgs itself (e.g. replies on Address Claims),
+ * this is the responsibility of a user space application or daemon.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+
+#include "j1939-priv.h"
+
+static inline name_t j1939_skb_to_name(const struct sk_buff *skb)
+{
+	return le64_to_cpup((__le64 *)skb->data);
+}
+
+static inline bool j1939_ac_msg_is_request(struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	int req_pgn;
+
+	if (skb->len < 3 || skcb->addr.pgn != J1939_PGN_REQUEST)
+		return false;
+
+	req_pgn = skb->data[0] | (skb->data[1] << 8) | (skb->data[2] << 16);
+
+	return req_pgn == J1939_PGN_ADDRESS_CLAIMED;
+}
+
+static int j1939_ac_verify_outgoing(struct j1939_priv *priv,
+				    struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+
+	if (skb->len != 8) {
+		netdev_notice(priv->ndev, "tx address claim with dlc %i\n",
+			      skb->len);
+		return -EPROTO;
+	}
+
+	if (skcb->addr.src_name != j1939_skb_to_name(skb)) {
+		netdev_notice(priv->ndev, "tx address claim with different name\n");
+		return -EPROTO;
+	}
+
+	if (skcb->addr.sa == J1939_NO_ADDR) {
+		netdev_notice(priv->ndev, "tx address claim with broadcast sa\n");
+		return -EPROTO;
+	}
+
+	/* ac must always be a broadcast */
+	if (skcb->addr.dst_name || skcb->addr.da != J1939_NO_ADDR) {
+		netdev_notice(priv->ndev, "tx address claim with dest, not broadcast\n");
+		return -EPROTO;
+	}
+	return 0;
+}
+
+int j1939_ac_fixup(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	int ret;
+	u8 addr;
+
+	/* network mgmt: address claiming msgs */
+	if (skcb->addr.pgn == J1939_PGN_ADDRESS_CLAIMED) {
+		struct j1939_ecu *ecu;
+
+		ret = j1939_ac_verify_outgoing(priv, skb);
+		/* return both when failure & when successful */
+		if (ret < 0)
+			return ret;
+		ecu = j1939_ecu_get_by_name(priv, skcb->addr.src_name);
+		if (!ecu)
+			return -ENODEV;
+
+		if (ecu->addr != skcb->addr.sa)
+			/* hold further traffic for ecu, remove from parent */
+			j1939_ecu_unmap(ecu);
+		j1939_ecu_put(ecu);
+	} else if (skcb->addr.src_name) {
+		/* assign source address */
+		addr = j1939_name_to_addr(priv, skcb->addr.src_name);
+		if (!j1939_address_is_unicast(addr) &&
+		    !j1939_ac_msg_is_request(skb)) {
+			netdev_notice(priv->ndev, "tx drop: invalid sa for name 0x%016llx\n",
+				      skcb->addr.src_name);
+			return -EADDRNOTAVAIL;
+		}
+		skcb->addr.sa = addr;
+	}
+
+	/* assign destination address */
+	if (skcb->addr.dst_name) {
+		addr = j1939_name_to_addr(priv, skcb->addr.dst_name);
+		if (!j1939_address_is_unicast(addr)) {
+			netdev_notice(priv->ndev, "tx drop: invalid da for name 0x%016llx\n",
+				      skcb->addr.dst_name);
+			return -EADDRNOTAVAIL;
+		}
+		skcb->addr.da = addr;
+	}
+	return 0;
+}
+
+static void j1939_ac_process(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_ecu *ecu, *prev;
+	name_t name;
+
+	if (skb->len != 8) {
+		netdev_notice(priv->ndev, "rx address claim with wrong dlc %i\n",
+			      skb->len);
+		return;
+	}
+
+	name = j1939_skb_to_name(skb);
+	skcb->addr.src_name = name;
+	if (!name) {
+		netdev_notice(priv->ndev, "rx address claim without name\n");
+		return;
+	}
+
+	if (!j1939_address_is_valid(skcb->addr.sa)) {
+		netdev_notice(priv->ndev, "rx address claim with broadcast sa\n");
+		return;
+	}
+
+	write_lock_bh(&priv->lock);
+
+	/* Few words on the ECU ref counting:
+	 *
+	 * First we get an ECU handle, either with
+	 * j1939_ecu_get_by_name_locked() (increments the ref counter)
+	 * or j1939_ecu_create_locked() (initializes an ECU object
+	 * with a ref counter of 1).
+	 *
+	 * j1939_ecu_unmap_locked() will decrement the ref counter,
+	 * but only if the ECU was mapped before. So "ecu" still
+	 * belongs to us.
+	 *
+	 * j1939_ecu_timer_start() will increment the ref counter
+	 * before it starts the timer, so we can put the ecu when
+	 * leaving this function.
+	 */
+	ecu = j1939_ecu_get_by_name_locked(priv, name);
+
+	if (ecu && ecu->addr == skcb->addr.sa) {
+		/* The ISO 11783-5 standard, in "4.5.2 - Address claim
+		 * requirements", states:
+		 *   d) No CF shall begin, or resume, transmission on the
+		 *      network until 250 ms after it has successfully claimed
+		 *      an address except when responding to a request for
+		 *      address-claimed.
+		 *
+		 * But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim
+		 * prioritization" show that the CF begins the transmission
+		 * after 250 ms from the first AC (address-claimed) message
+		 * even if it sends another AC message during that time window
+		 * to resolve the address contention with another CF.
+		 *
+		 * As stated in "4.4.2.3 - Address-claimed message":
+		 *   In order to successfully claim an address, the CF sending
+		 *   an address claimed message shall not receive a contending
+		 *   claim from another CF for at least 250 ms.
+		 *
+		 * As stated in "4.4.3.2 - NAME management (NM) message":
+		 *   1) A commanding CF can
+		 *      d) request that a CF with a specified NAME transmit
+		 *         the address-claimed message with its current NAME.
+		 *   2) A target CF shall
+		 *      d) send an address-claimed message in response to a
+		 *         request for a matching NAME
+		 *
+		 * Taking the above arguments into account, the 250 ms wait is
+		 * requested only during network initialization.
+		 *
+		 * Do not restart the timer on AC message if both the NAME and
+		 * the address match and so if the address has already been
+		 * claimed (timer has expired) or the AC message has been sent
+		 * to resolve the contention with another CF (timer is still
+		 * running).
+		 */
+		goto out_ecu_put;
+	}
+
+	if (!ecu && j1939_address_is_unicast(skcb->addr.sa))
+		ecu = j1939_ecu_create_locked(priv, name);
+
+	if (IS_ERR_OR_NULL(ecu))
+		goto out_unlock_bh;
+
+	/* cancel pending (previous) address claim */
+	j1939_ecu_timer_cancel(ecu);
+
+	if (j1939_address_is_idle(skcb->addr.sa)) {
+		j1939_ecu_unmap_locked(ecu);
+		goto out_ecu_put;
+	}
+
+	/* save new addr */
+	if (ecu->addr != skcb->addr.sa)
+		j1939_ecu_unmap_locked(ecu);
+	ecu->addr = skcb->addr.sa;
+
+	prev = j1939_ecu_get_by_addr_locked(priv, skcb->addr.sa);
+	if (prev) {
+		if (ecu->name > prev->name) {
+			j1939_ecu_unmap_locked(ecu);
+			j1939_ecu_put(prev);
+			goto out_ecu_put;
+		} else {
+			/* kick prev if less or equal */
+			j1939_ecu_unmap_locked(prev);
+			j1939_ecu_put(prev);
+		}
+	}
+
+	j1939_ecu_timer_start(ecu);
+ out_ecu_put:
+	j1939_ecu_put(ecu);
+ out_unlock_bh:
+	write_unlock_bh(&priv->lock);
+}
+
+void j1939_ac_recv(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct j1939_ecu *ecu;
+
+	/* network mgmt */
+	if (skcb->addr.pgn == J1939_PGN_ADDRESS_CLAIMED) {
+		j1939_ac_process(priv, skb);
+	} else if (j1939_address_is_unicast(skcb->addr.sa)) {
+		/* assign source name */
+		ecu = j1939_ecu_get_by_addr(priv, skcb->addr.sa);
+		if (ecu) {
+			skcb->addr.src_name = ecu->name;
+			j1939_ecu_put(ecu);
+		}
+	}
+
+	/* assign destination name */
+	ecu = j1939_ecu_get_by_addr(priv, skcb->addr.da);
+	if (ecu) {
+		skcb->addr.dst_name = ecu->name;
+		j1939_ecu_put(ecu);
+	}
+}

linux-7.2.3/net/can/j1939/bus.c

@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Kurt Van Dijck <kurt.van.dijck@eia.be>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Marc Kleine-Budde <kernel@pengutronix.de>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Oleksij Rempel <kernel@pengutronix.de>
+
+/* bus for j1939 remote devices
+ * Since rtnetlink, no real bus is used.
+ */
+
+#include <net/sock.h>
+
+#include "j1939-priv.h"
+
+static void __j1939_ecu_release(struct kref *kref)
+{
+	struct j1939_ecu *ecu = container_of(kref, struct j1939_ecu, kref);
+	struct j1939_priv *priv = ecu->priv;
+
+	list_del(&ecu->list);
+	netdev_put(priv->ndev, &ecu->priv_dev_tracker);
+	kfree(ecu);
+	j1939_priv_put(priv);
+}
+
+void j1939_ecu_put(struct j1939_ecu *ecu)
+{
+	kref_put(&ecu->kref, __j1939_ecu_release);
+}
+
+static void j1939_ecu_get(struct j1939_ecu *ecu)
+{
+	kref_get(&ecu->kref);
+}
+
+static bool j1939_ecu_is_mapped_locked(struct j1939_ecu *ecu)
+{
+	struct j1939_priv *priv = ecu->priv;
+
+	lockdep_assert_held(&priv->lock);
+
+	return j1939_ecu_find_by_addr_locked(priv, ecu->addr) == ecu;
+}
+
+/* ECU device interface */
+/* map ECU to a bus address space */
+static void j1939_ecu_map_locked(struct j1939_ecu *ecu)
+{
+	struct j1939_priv *priv = ecu->priv;
+	struct j1939_addr_ent *ent;
+
+	lockdep_assert_held(&priv->lock);
+
+	if (!j1939_address_is_unicast(ecu->addr))
+		return;
+
+	ent = &priv->ents[ecu->addr];
+
+	if (ent->ecu) {
+		netdev_warn(priv->ndev, "Trying to map already mapped ECU, addr: 0x%02x, name: 0x%016llx. Skip it.\n",
+			    ecu->addr, ecu->name);
+		return;
+	}
+
+	j1939_ecu_get(ecu);
+	ent->ecu = ecu;
+	ent->nusers += ecu->nusers;
+}
+
+/* unmap ECU from a bus address space */
+void j1939_ecu_unmap_locked(struct j1939_ecu *ecu)
+{
+	struct j1939_priv *priv = ecu->priv;
+	struct j1939_addr_ent *ent;
+
+	lockdep_assert_held(&priv->lock);
+
+	if (!j1939_address_is_unicast(ecu->addr))
+		return;
+
+	if (!j1939_ecu_is_mapped_locked(ecu))
+		return;
+
+	ent = &priv->ents[ecu->addr];
+	ent->ecu = NULL;
+	ent->nusers -= ecu->nusers;
+	j1939_ecu_put(ecu);
+}
+
+void j1939_ecu_unmap(struct j1939_ecu *ecu)
+{
+	write_lock_bh(&ecu->priv->lock);
+	j1939_ecu_unmap_locked(ecu);
+	write_unlock_bh(&ecu->priv->lock);
+}
+
+void j1939_ecu_unmap_all(struct j1939_priv *priv)
+{
+	int i;
+
+	write_lock_bh(&priv->lock);
+	for (i = 0; i < ARRAY_SIZE(priv->ents); i++)
+		if (priv->ents[i].ecu)
+			j1939_ecu_unmap_locked(priv->ents[i].ecu);
+	write_unlock_bh(&priv->lock);
+}
+
+void j1939_ecu_timer_start(struct j1939_ecu *ecu)
+{
+	/* The ECU is held here and released in the
+	 * j1939_ecu_timer_handler() or j1939_ecu_timer_cancel().
+	 */
+	j1939_ecu_get(ecu);
+
+	/* Schedule timer in 250 msec to commit address change. */
+	hrtimer_start(&ecu->ac_timer, ms_to_ktime(250),
+		      HRTIMER_MODE_REL_SOFT);
+}
+
+void j1939_ecu_timer_cancel(struct j1939_ecu *ecu)
+{
+	if (hrtimer_cancel(&ecu->ac_timer))
+		j1939_ecu_put(ecu);
+}
+
+static enum hrtimer_restart j1939_ecu_timer_handler(struct hrtimer *hrtimer)
+{
+	struct j1939_ecu *ecu =
+		container_of(hrtimer, struct j1939_ecu, ac_timer);
+	struct j1939_priv *priv = ecu->priv;
+
+	write_lock_bh(&priv->lock);
+	/* TODO: can we test if ecu->addr is unicast before starting
+	 * the timer?
+	 */
+	j1939_ecu_map_locked(ecu);
+
+	/* The corresponding j1939_ecu_get() is in
+	 * j1939_ecu_timer_start().
+	 */
+	j1939_ecu_put(ecu);
+	write_unlock_bh(&priv->lock);
+
+	return HRTIMER_NORESTART;
+}
+
+struct j1939_ecu *j1939_ecu_create_locked(struct j1939_priv *priv, name_t name)
+{
+	struct j1939_ecu *ecu;
+
+	lockdep_assert_held(&priv->lock);
+
+	ecu = kzalloc_obj(*ecu, gfp_any());
+	if (!ecu)
+		return ERR_PTR(-ENOMEM);
+	kref_init(&ecu->kref);
+	netdev_hold(priv->ndev, &ecu->priv_dev_tracker, gfp_any());
+	ecu->addr = J1939_IDLE_ADDR;
+	ecu->name = name;
+
+	hrtimer_setup(&ecu->ac_timer, j1939_ecu_timer_handler, CLOCK_MONOTONIC,
+		      HRTIMER_MODE_REL_SOFT);
+	INIT_LIST_HEAD(&ecu->list);
+
+	j1939_priv_get(priv);
+	ecu->priv = priv;
+	list_add_tail(&ecu->list, &priv->ecus);
+
+	return ecu;
+}
+
+struct j1939_ecu *j1939_ecu_find_by_addr_locked(struct j1939_priv *priv,
+						u8 addr)
+{
+	lockdep_assert_held(&priv->lock);
+
+	return priv->ents[addr].ecu;
+}
+
+struct j1939_ecu *j1939_ecu_get_by_addr_locked(struct j1939_priv *priv, u8 addr)
+{
+	struct j1939_ecu *ecu;
+
+	lockdep_assert_held(&priv->lock);
+
+	if (!j1939_address_is_unicast(addr))
+		return NULL;
+
+	ecu = j1939_ecu_find_by_addr_locked(priv, addr);
+	if (ecu)
+		j1939_ecu_get(ecu);
+
+	return ecu;
+}
+
+struct j1939_ecu *j1939_ecu_get_by_addr(struct j1939_priv *priv, u8 addr)
+{
+	struct j1939_ecu *ecu;
+
+	read_lock_bh(&priv->lock);
+	ecu = j1939_ecu_get_by_addr_locked(priv, addr);
+	read_unlock_bh(&priv->lock);
+
+	return ecu;
+}
+
+/* get pointer to ecu without increasing ref counter */
+static struct j1939_ecu *j1939_ecu_find_by_name_locked(struct j1939_priv *priv,
+						       name_t name)
+{
+	struct j1939_ecu *ecu;
+
+	lockdep_assert_held(&priv->lock);
+
+	list_for_each_entry(ecu, &priv->ecus, list) {
+		if (ecu->name == name)
+			return ecu;
+	}
+
+	return NULL;
+}
+
+struct j1939_ecu *j1939_ecu_get_by_name_locked(struct j1939_priv *priv,
+					       name_t name)
+{
+	struct j1939_ecu *ecu;
+
+	lockdep_assert_held(&priv->lock);
+
+	if (!name)
+		return NULL;
+
+	ecu = j1939_ecu_find_by_name_locked(priv, name);
+	if (ecu)
+		j1939_ecu_get(ecu);
+
+	return ecu;
+}
+
+struct j1939_ecu *j1939_ecu_get_by_name(struct j1939_priv *priv, name_t name)
+{
+	struct j1939_ecu *ecu;
+
+	read_lock_bh(&priv->lock);
+	ecu = j1939_ecu_get_by_name_locked(priv, name);
+	read_unlock_bh(&priv->lock);
+
+	return ecu;
+}
+
+u8 j1939_name_to_addr(struct j1939_priv *priv, name_t name)
+{
+	struct j1939_ecu *ecu;
+	int addr = J1939_IDLE_ADDR;
+
+	if (!name)
+		return J1939_NO_ADDR;
+
+	read_lock_bh(&priv->lock);
+	ecu = j1939_ecu_find_by_name_locked(priv, name);
+	if (ecu && j1939_ecu_is_mapped_locked(ecu))
+		/* ecu's SA is registered */
+		addr = ecu->addr;
+
+	read_unlock_bh(&priv->lock);
+
+	return addr;
+}
+
+/* TX addr/name accounting
+ * Transport protocol needs to know if a SA is local or not
+ * These functions originate from userspace manipulating sockets,
+ * so locking is straigforward
+ */
+
+int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa)
+{
+	struct j1939_ecu *ecu;
+	int err = 0;
+
+	write_lock_bh(&priv->lock);
+
+	if (j1939_address_is_unicast(sa))
+		priv->ents[sa].nusers++;
+
+	if (!name)
+		goto done;
+
+	ecu = j1939_ecu_get_by_name_locked(priv, name);
+	if (!ecu)
+		ecu = j1939_ecu_create_locked(priv, name);
+	err = PTR_ERR_OR_ZERO(ecu);
+	if (err) {
+		if (j1939_address_is_unicast(sa))
+			priv->ents[sa].nusers--;
+		goto done;
+	}
+
+	ecu->nusers++;
+	/* TODO: do we care if ecu->addr != sa? */
+	if (j1939_ecu_is_mapped_locked(ecu))
+		/* ecu's sa is active already */
+		priv->ents[ecu->addr].nusers++;
+
+ done:
+	write_unlock_bh(&priv->lock);
+
+	return err;
+}
+
+void j1939_local_ecu_put(struct j1939_priv *priv, name_t name, u8 sa)
+{
+	struct j1939_ecu *ecu;
+
+	write_lock_bh(&priv->lock);
+
+	if (j1939_address_is_unicast(sa))
+		priv->ents[sa].nusers--;
+
+	if (!name)
+		goto done;
+
+	ecu = j1939_ecu_find_by_name_locked(priv, name);
+	if (WARN_ON_ONCE(!ecu))
+		goto done;
+
+	ecu->nusers--;
+	/* TODO: do we care if ecu->addr != sa? */
+	if (j1939_ecu_is_mapped_locked(ecu))
+		/* ecu's sa is active already */
+		priv->ents[ecu->addr].nusers--;
+	j1939_ecu_put(ecu);
+
+ done:
+	write_unlock_bh(&priv->lock);
+}

linux-7.2.3/net/can/j1939/j1939-priv.h

@@ -0,0 +1,348 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Kurt Van Dijck <kurt.van.dijck@eia.be>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Marc Kleine-Budde <kernel@pengutronix.de>
+// Copyright (c) 2017-2019 Pengutronix,
+//                         Oleksij Rempel <kernel@pengutronix.de>
+
+#ifndef _J1939_PRIV_H_
+#define _J1939_PRIV_H_
+
+#include <linux/can/j1939.h>
+#include <net/sock.h>
+
+/* Timeout to receive the abort signal over loop back. In case CAN
+ * bus is open, the timeout should be triggered.
+ */
+#define J1939_XTP_ABORT_TIMEOUT_MS 500
+#define J1939_SIMPLE_ECHO_TIMEOUT_MS (10 * 1000)
+
+struct j1939_session;
+enum j1939_sk_errqueue_type {
+	J1939_ERRQUEUE_TX_ACK,
+	J1939_ERRQUEUE_TX_SCHED,
+	J1939_ERRQUEUE_TX_ABORT,
+	J1939_ERRQUEUE_RX_RTS,
+	J1939_ERRQUEUE_RX_DPO,
+	J1939_ERRQUEUE_RX_ABORT,
+};
+
+/* j1939 devices */
+struct j1939_ecu {
+	struct list_head list;
+	name_t name;
+	u8 addr;
+
+	/* indicates that this ecu successfully claimed @sa as its address */
+	struct hrtimer ac_timer;
+	struct kref kref;
+	struct j1939_priv *priv;
+	netdevice_tracker priv_dev_tracker;
+
+	/* count users, to help transport protocol decide for interaction */
+	int nusers;
+};
+
+struct j1939_priv {
+	struct list_head ecus;
+	/* local list entry in priv
+	 * These allow irq (& softirq) context lookups on j1939 devices
+	 * This approach (separate lists) is done as the other 2 alternatives
+	 * are not easier or even wrong
+	 * 1) using the pure kobject methods involves mutexes, which are not
+	 *    allowed in irq context.
+	 * 2) duplicating data structures would require a lot of synchronization
+	 *    code
+	 * usage:
+	 */
+
+	/* segments need a lock to protect the above list */
+	rwlock_t lock;
+
+	struct net_device *ndev;
+	netdevice_tracker dev_tracker;
+
+	/* list of 256 ecu ptrs, that cache the claimed addresses.
+	 * also protected by the above lock
+	 */
+	struct j1939_addr_ent {
+		struct j1939_ecu *ecu;
+		/* count users, to help transport protocol */
+		int nusers;
+	} ents[256];
+
+	struct kref kref;
+
+	/* List of active sessions to prevent start of conflicting
+	 * one.
+	 *
+	 * Do not start two sessions of same type, addresses and
+	 * direction.
+	 */
+	struct list_head active_session_list;
+
+	/* protects active_session_list */
+	spinlock_t active_session_list_lock;
+
+	unsigned int tp_max_packet_size;
+
+	/* lock for j1939_socks list */
+	rwlock_t j1939_socks_lock;
+	struct list_head j1939_socks;
+
+	struct kref rx_kref;
+	u32 rx_tskey;
+};
+
+void j1939_ecu_put(struct j1939_ecu *ecu);
+
+/* keep the cache of what is local */
+int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa);
+void j1939_local_ecu_put(struct j1939_priv *priv, name_t name, u8 sa);
+
+static inline bool j1939_address_is_unicast(u8 addr)
+{
+	return addr <= J1939_MAX_UNICAST_ADDR;
+}
+
+static inline bool j1939_address_is_idle(u8 addr)
+{
+	return addr == J1939_IDLE_ADDR;
+}
+
+static inline bool j1939_address_is_valid(u8 addr)
+{
+	return addr != J1939_NO_ADDR;
+}
+
+static inline bool j1939_pgn_is_pdu1(pgn_t pgn)
+{
+	/* ignore dp & res bits for this */
+	return (pgn & 0xff00) < 0xf000;
+}
+
+/* utility to correctly unmap an ECU */
+void j1939_ecu_unmap_locked(struct j1939_ecu *ecu);
+void j1939_ecu_unmap(struct j1939_ecu *ecu);
+
+u8 j1939_name_to_addr(struct j1939_priv *priv, name_t name);
+struct j1939_ecu *j1939_ecu_find_by_addr_locked(struct j1939_priv *priv,
+						u8 addr);
+struct j1939_ecu *j1939_ecu_get_by_addr(struct j1939_priv *priv, u8 addr);
+struct j1939_ecu *j1939_ecu_get_by_addr_locked(struct j1939_priv *priv,
+					       u8 addr);
+struct j1939_ecu *j1939_ecu_get_by_name(struct j1939_priv *priv, name_t name);
+struct j1939_ecu *j1939_ecu_get_by_name_locked(struct j1939_priv *priv,
+					       name_t name);
+
+enum j1939_transfer_type {
+	J1939_TP,
+	J1939_ETP,
+	J1939_SIMPLE,
+};
+
+struct j1939_addr {
+	name_t src_name;
+	name_t dst_name;
+	pgn_t pgn;
+
+	u8 sa;
+	u8 da;
+
+	u8 type;
+};
+
+/* control buffer of the sk_buff */
+struct j1939_sk_buff_cb {
+	/* Offset in bytes within one ETP session */
+	u32 offset;
+
+	/* for tx, MSG_SYN will be used to sync on sockets */
+	u32 msg_flags;
+	u32 tskey;
+
+	struct j1939_addr addr;
+
+	/* Flags for quick lookups during skb processing.
+	 * These are set in the receive path only.
+	 */
+#define J1939_ECU_LOCAL_SRC BIT(0)
+#define J1939_ECU_LOCAL_DST BIT(1)
+	u8 flags;
+
+	priority_t priority;
+};
+
+static inline
+struct j1939_sk_buff_cb *j1939_skb_to_cb(const struct sk_buff *skb)
+{
+	BUILD_BUG_ON(sizeof(struct j1939_sk_buff_cb) > sizeof(skb->cb));
+
+	return (struct j1939_sk_buff_cb *)skb->cb;
+}
+
+int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb);
+void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb);
+bool j1939_sk_recv_match(struct j1939_priv *priv,
+			 struct j1939_sk_buff_cb *skcb);
+void j1939_sk_send_loop_abort(struct sock *sk, int err);
+void j1939_sk_errqueue(struct j1939_session *session,
+		       enum j1939_sk_errqueue_type type);
+void j1939_sk_queue_activate_next(struct j1939_session *session);
+
+/* stack entries */
+struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
+				    struct sk_buff *skb, size_t size);
+int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb);
+int j1939_ac_fixup(struct j1939_priv *priv, struct sk_buff *skb);
+void j1939_ac_recv(struct j1939_priv *priv, struct sk_buff *skb);
+void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb);
+
+/* network management */
+struct j1939_ecu *j1939_ecu_create_locked(struct j1939_priv *priv, name_t name);
+
+void j1939_ecu_timer_start(struct j1939_ecu *ecu);
+void j1939_ecu_timer_cancel(struct j1939_ecu *ecu);
+void j1939_ecu_unmap_all(struct j1939_priv *priv);
+
+struct j1939_priv *j1939_netdev_start(struct net_device *ndev);
+void j1939_netdev_stop(struct j1939_priv *priv);
+
+void j1939_priv_put(struct j1939_priv *priv);
+void j1939_priv_get(struct j1939_priv *priv);
+
+/* notify/alert all j1939 sockets bound to ifindex */
+void j1939_sk_netdev_event_netdown(struct j1939_priv *priv);
+void j1939_sk_netdev_event_unregister(struct j1939_priv *priv);
+int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk);
+void j1939_tp_init(struct j1939_priv *priv);
+
+/* decrement pending skb for a j1939 socket */
+void j1939_sock_pending_del(struct sock *sk);
+
+enum j1939_session_state {
+	J1939_SESSION_NEW,
+	J1939_SESSION_ACTIVE,
+	/* waiting for abort signal on the bus */
+	J1939_SESSION_WAITING_ABORT,
+	J1939_SESSION_ACTIVE_MAX,
+	J1939_SESSION_DONE,
+};
+
+struct j1939_session {
+	struct j1939_priv *priv;
+	netdevice_tracker priv_dev_tracker;
+	struct list_head active_session_list_entry;
+	struct list_head sk_session_queue_entry;
+	struct kref kref;
+	struct sock *sk;
+
+	/* ifindex, src, dst, pgn define the session block
+	 * the are _never_ modified after insertion in the list
+	 * this decreases locking problems a _lot_
+	 */
+	struct j1939_sk_buff_cb skcb;
+	struct sk_buff_head skb_queue;
+
+	/* all tx related stuff (last_txcmd, pkt.tx)
+	 * is protected (modified only) with the txtimer hrtimer
+	 * 'total' & 'block' are never changed,
+	 * last_cmd, last & block are protected by ->lock
+	 * this means that the tx may run after cts is received that should
+	 * have stopped tx, but this time discrepancy is never avoided anyhow
+	 */
+	u8 last_cmd, last_txcmd;
+	bool transmission;
+	bool extd;
+	/* Total message size, number of bytes */
+	unsigned int total_message_size;
+	/* Total number of bytes queue from socket to the session */
+	unsigned int total_queued_size;
+	unsigned int tx_retry;
+
+	int err;
+	u32 tskey;
+	enum j1939_session_state state;
+
+	/* Packets counters for a (extended) transfer session. The packet is
+	 * maximal of 7 bytes.
+	 */
+	struct {
+		/* total - total number of packets for this session */
+		unsigned int total;
+		/* last - last packet of a transfer block after which
+		 * responder should send ETP.CM_CTS and originator
+		 * ETP.CM_DPO
+		 */
+		unsigned int last;
+		/* tx - number of packets send by originator node.
+		 * this counter can be set back if responder node
+		 * didn't received all packets send by originator.
+		 */
+		unsigned int tx;
+		unsigned int tx_acked;
+		/* rx - number of packets received */
+		unsigned int rx;
+		/* block - amount of packets expected in one block */
+		unsigned int block;
+		/* dpo - ETP.CM_DPO, Data Packet Offset */
+		unsigned int dpo;
+	} pkt;
+	struct hrtimer txtimer, rxtimer;
+};
+
+struct j1939_sock {
+	struct sock sk; /* must be first to skip with memset */
+	struct j1939_priv *priv;
+	struct list_head list;
+
+#define J1939_SOCK_BOUND BIT(0)
+#define J1939_SOCK_CONNECTED BIT(1)
+#define J1939_SOCK_PROMISC BIT(2)
+#define J1939_SOCK_ERRQUEUE BIT(3)
+	int state;
+
+	int ifindex;
+	struct j1939_addr addr;
+	spinlock_t filters_lock;
+	struct j1939_filter *filters;
+	int nfilters;
+	pgn_t pgn_rx_filter;
+
+	/* j1939 may emit equal PGN (!= equal CAN-id's) out of order
+	 * when transport protocol comes in.
+	 * To allow emitting in order, keep a 'pending' nr. of packets
+	 */
+	atomic_t skb_pending;
+	wait_queue_head_t waitq;
+
+	/* lock for the sk_session_queue list */
+	spinlock_t sk_session_queue_lock;
+	struct list_head sk_session_queue;
+};
+
+static inline struct j1939_sock *j1939_sk(const struct sock *sk)
+{
+	return container_of(sk, struct j1939_sock, sk);
+}
+
+void j1939_session_get(struct j1939_session *session);
+void j1939_session_put(struct j1939_session *session);
+void j1939_session_skb_queue(struct j1939_session *session,
+			     struct sk_buff *skb);
+int j1939_session_activate(struct j1939_session *session);
+void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec);
+void j1939_session_timers_cancel(struct j1939_session *session);
+
+#define J1939_MIN_TP_PACKET_SIZE 9
+#define J1939_MAX_TP_PACKET_SIZE (7 * 0xff)
+#define J1939_MAX_ETP_PACKET_SIZE (7 * 0x00ffffff)
+
+#define J1939_REGULAR 0
+#define J1939_EXTENDED 1
+
+/* CAN protocol */
+extern const struct can_proto j1939_can_proto;
+
+#endif /* _J1939_PRIV_H_ */

linux-7.2.3/net/can/j1939/main.c

@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2010-2011 EIA Electronics,
+//                         Pieter Beyens <pieter.beyens@eia.be>
+// 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>
+
+/* Core of can-j1939 that links j1939 to CAN. */
+
+#include <linux/can/can-ml.h>
+#include <linux/can/core.h>
+#include <linux/can/skb.h>
+#include <linux/if_arp.h>
+#include <linux/module.h>
+
+#include "j1939-priv.h"
+
+MODULE_DESCRIPTION("PF_CAN SAE J1939");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("EIA Electronics (Kurt Van Dijck & Pieter Beyens)");
+MODULE_ALIAS("can-proto-" __stringify(CAN_J1939));
+
+/* LOWLEVEL CAN interface */
+
+/* CAN_HDR: #bytes before can_frame data part */
+#define J1939_CAN_HDR (offsetof(struct can_frame, data))
+
+/* lowest layer */
+static void j1939_can_recv(struct sk_buff *iskb, void *data)
+{
+	struct j1939_priv *priv = data;
+	struct sk_buff *skb;
+	struct j1939_sk_buff_cb *skcb, *iskcb;
+	struct can_frame *cf;
+
+	/* make sure we only get Classical CAN frames */
+	if (!can_is_can_skb(iskb))
+		return;
+
+	/* create a copy of the skb
+	 * j1939 only delivers the real data bytes,
+	 * the header goes into sockaddr.
+	 * j1939 may not touch the incoming skb in such way
+	 */
+	skb = skb_clone(iskb, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	j1939_priv_get(priv);
+	can_skb_set_owner(skb, iskb->sk);
+
+	/* get a pointer to the header of the skb
+	 * the skb payload (pointer) is moved, so that the next skb_data
+	 * returns the actual payload
+	 */
+	cf = (void *)skb->data;
+	skb_pull(skb, J1939_CAN_HDR);
+
+	/* fix length, set to dlc, with 8 maximum */
+	skb_trim(skb, min_t(uint8_t, cf->len, 8));
+
+	/* set addr */
+	skcb = j1939_skb_to_cb(skb);
+	memset(skcb, 0, sizeof(*skcb));
+
+	iskcb = j1939_skb_to_cb(iskb);
+	skcb->tskey = iskcb->tskey;
+	skcb->priority = (cf->can_id >> 26) & 0x7;
+	skcb->addr.sa = cf->can_id;
+	skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
+	/* set default message type */
+	skcb->addr.type = J1939_TP;
+
+	if (!j1939_address_is_valid(skcb->addr.sa)) {
+		netdev_err_once(priv->ndev, "%s: sa is broadcast address, ignoring!\n",
+				__func__);
+		goto done;
+	}
+
+	if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
+		/* Type 1: with destination address */
+		skcb->addr.da = skcb->addr.pgn;
+		/* normalize pgn: strip dst address */
+		skcb->addr.pgn &= 0x3ff00;
+	} else {
+		/* set broadcast address */
+		skcb->addr.da = J1939_NO_ADDR;
+	}
+
+	/* update localflags */
+	read_lock_bh(&priv->lock);
+	if (j1939_address_is_unicast(skcb->addr.sa) &&
+	    priv->ents[skcb->addr.sa].nusers)
+		skcb->flags |= J1939_ECU_LOCAL_SRC;
+	if (j1939_address_is_unicast(skcb->addr.da) &&
+	    priv->ents[skcb->addr.da].nusers)
+		skcb->flags |= J1939_ECU_LOCAL_DST;
+	read_unlock_bh(&priv->lock);
+
+	/* deliver into the j1939 stack ... */
+	j1939_ac_recv(priv, skb);
+
+	if (j1939_tp_recv(priv, skb))
+		/* this means the transport layer processed the message */
+		goto done;
+
+	j1939_simple_recv(priv, skb);
+	j1939_sk_recv(priv, skb);
+ done:
+	j1939_priv_put(priv);
+	kfree_skb(skb);
+}
+
+/* NETDEV MANAGEMENT */
+
+/* values for can_rx_(un)register */
+#define J1939_CAN_ID CAN_EFF_FLAG
+#define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG)
+
+static DEFINE_MUTEX(j1939_netdev_lock);
+
+static struct j1939_priv *j1939_priv_create(struct net_device *ndev)
+{
+	struct j1939_priv *priv;
+
+	priv = kzalloc_obj(*priv);
+	if (!priv)
+		return NULL;
+
+	rwlock_init(&priv->lock);
+	INIT_LIST_HEAD(&priv->ecus);
+	priv->ndev = ndev;
+	kref_init(&priv->kref);
+	kref_init(&priv->rx_kref);
+	netdev_hold(ndev, &priv->dev_tracker, GFP_KERNEL);
+
+	netdev_dbg(priv->ndev, "%s : 0x%p\n", __func__, priv);
+
+	return priv;
+}
+
+static inline void j1939_priv_set(struct net_device *ndev,
+				  struct j1939_priv *priv)
+{
+	struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
+
+	can_ml->j1939_priv = priv;
+}
+
+static void __j1939_priv_release(struct kref *kref)
+{
+	struct j1939_priv *priv = container_of(kref, struct j1939_priv, kref);
+	struct net_device *ndev = priv->ndev;
+
+	netdev_dbg(priv->ndev, "%s: 0x%p\n", __func__, priv);
+
+	WARN_ON_ONCE(!list_empty(&priv->active_session_list));
+	WARN_ON_ONCE(!list_empty(&priv->ecus));
+	WARN_ON_ONCE(!list_empty(&priv->j1939_socks));
+
+	netdev_put(ndev, &priv->dev_tracker);
+	kfree(priv);
+}
+
+void j1939_priv_put(struct j1939_priv *priv)
+{
+	kref_put(&priv->kref, __j1939_priv_release);
+}
+
+void j1939_priv_get(struct j1939_priv *priv)
+{
+	kref_get(&priv->kref);
+}
+
+static int j1939_can_rx_register(struct j1939_priv *priv)
+{
+	struct net_device *ndev = priv->ndev;
+	int ret;
+
+	j1939_priv_get(priv);
+	ret = can_rx_register(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
+			      j1939_can_recv, priv, "j1939", NULL);
+	if (ret < 0) {
+		j1939_priv_put(priv);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void j1939_can_rx_unregister(struct j1939_priv *priv)
+{
+	struct net_device *ndev = priv->ndev;
+
+	can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
+			  j1939_can_recv, priv);
+
+	/* The last reference of priv is dropped by the RCU deferred
+	 * j1939_sk_sock_destruct() of the last socket, so we can
+	 * safely drop this reference here.
+	 */
+	j1939_priv_put(priv);
+}
+
+static void __j1939_rx_release(struct kref *kref)
+	__releases(&j1939_netdev_lock)
+{
+	struct j1939_priv *priv = container_of(kref, struct j1939_priv,
+					       rx_kref);
+
+	j1939_can_rx_unregister(priv);
+	j1939_ecu_unmap_all(priv);
+	j1939_priv_set(priv->ndev, NULL);
+	mutex_unlock(&j1939_netdev_lock);
+}
+
+/* get pointer to priv without increasing ref counter */
+static inline struct j1939_priv *j1939_ndev_to_priv(struct net_device *ndev)
+{
+	struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
+
+	return can_ml->j1939_priv;
+}
+
+static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev)
+{
+	struct j1939_priv *priv;
+
+	lockdep_assert_held(&j1939_netdev_lock);
+
+	priv = j1939_ndev_to_priv(ndev);
+	if (priv)
+		j1939_priv_get(priv);
+
+	return priv;
+}
+
+static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev)
+{
+	struct j1939_priv *priv;
+
+	mutex_lock(&j1939_netdev_lock);
+	priv = j1939_priv_get_by_ndev_locked(ndev);
+	mutex_unlock(&j1939_netdev_lock);
+
+	return priv;
+}
+
+struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
+{
+	struct j1939_priv *priv, *priv_new;
+	int ret;
+
+	mutex_lock(&j1939_netdev_lock);
+	priv = j1939_priv_get_by_ndev_locked(ndev);
+	if (priv) {
+		kref_get(&priv->rx_kref);
+		mutex_unlock(&j1939_netdev_lock);
+		return priv;
+	}
+	mutex_unlock(&j1939_netdev_lock);
+
+	priv = j1939_priv_create(ndev);
+	if (!priv)
+		return ERR_PTR(-ENOMEM);
+
+	j1939_tp_init(priv);
+	rwlock_init(&priv->j1939_socks_lock);
+	INIT_LIST_HEAD(&priv->j1939_socks);
+
+	mutex_lock(&j1939_netdev_lock);
+	priv_new = j1939_priv_get_by_ndev_locked(ndev);
+	if (priv_new) {
+		/* Someone was faster than us, use their priv and roll
+		 * back our's.
+		 */
+		kref_get(&priv_new->rx_kref);
+		mutex_unlock(&j1939_netdev_lock);
+		netdev_put(ndev, &priv->dev_tracker);
+		kfree(priv);
+		return priv_new;
+	}
+	j1939_priv_set(ndev, priv);
+
+	ret = j1939_can_rx_register(priv);
+	if (ret < 0)
+		goto out_priv_put;
+
+	mutex_unlock(&j1939_netdev_lock);
+	return priv;
+
+ out_priv_put:
+	j1939_priv_set(ndev, NULL);
+	mutex_unlock(&j1939_netdev_lock);
+
+	netdev_put(ndev, &priv->dev_tracker);
+	kfree(priv);
+
+	return ERR_PTR(ret);
+}
+
+void j1939_netdev_stop(struct j1939_priv *priv)
+{
+	kref_put_mutex(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
+	j1939_priv_put(priv);
+}
+
+int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
+{
+	int ret, dlc;
+	canid_t canid;
+	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
+	struct can_frame *cf;
+
+	/* apply sanity checks */
+	if (j1939_pgn_is_pdu1(skcb->addr.pgn))
+		skcb->addr.pgn &= J1939_PGN_PDU1_MAX;
+	else
+		skcb->addr.pgn &= J1939_PGN_MAX;
+
+	if (skcb->priority > 7)
+		skcb->priority = 6;
+
+	ret = j1939_ac_fixup(priv, skb);
+	if (unlikely(ret))
+		goto failed;
+	dlc = skb->len;
+
+	/* re-claim the CAN_HDR from the SKB */
+	cf = skb_push(skb, J1939_CAN_HDR);
+
+	/* initialize header structure */
+	memset(cf, 0, J1939_CAN_HDR);
+
+	/* make it a full can frame again */
+	skb_put_zero(skb, 8 - dlc);
+
+	canid = CAN_EFF_FLAG |
+		(skcb->priority << 26) |
+		(skcb->addr.pgn << 8) |
+		skcb->addr.sa;
+	if (j1939_pgn_is_pdu1(skcb->addr.pgn))
+		canid |= skcb->addr.da << 8;
+
+	cf->can_id = canid;
+	cf->len = dlc;
+
+	return can_send(skb, 1);
+
+ failed:
+	kfree_skb(skb);
+	return ret;
+}
+
+static int j1939_netdev_notify(struct notifier_block *nb,
+			       unsigned long msg, void *data)
+{
+	struct net_device *ndev = netdev_notifier_info_to_dev(data);
+	struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
+	struct j1939_priv *priv;
+
+	if (!can_ml)
+		goto notify_done;
+
+	priv = j1939_priv_get_by_ndev(ndev);
+	if (!priv)
+		goto notify_done;
+
+	switch (msg) {
+	case NETDEV_DOWN:
+		j1939_cancel_active_session(priv, NULL);
+		j1939_sk_netdev_event_netdown(priv);
+		j1939_ecu_unmap_all(priv);
+		break;
+	case NETDEV_UNREGISTER:
+		j1939_cancel_active_session(priv, NULL);
+		j1939_sk_netdev_event_netdown(priv);
+		j1939_sk_netdev_event_unregister(priv);
+		break;
+	}
+
+	j1939_priv_put(priv);
+
+notify_done:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block j1939_netdev_notifier = {
+	.notifier_call = j1939_netdev_notify,
+};
+
+/* MODULE interface */
+static __init int j1939_module_init(void)
+{
+	int ret;
+
+	pr_info("can: SAE J1939\n");
+
+	ret = register_netdevice_notifier(&j1939_netdev_notifier);
+	if (ret)
+		goto fail_notifier;
+
+	ret = can_proto_register(&j1939_can_proto);
+	if (ret < 0) {
+		pr_err("can: registration of j1939 protocol failed\n");
+		goto fail_sk;
+	}
+
+	return 0;
+
+ fail_sk:
+	unregister_netdevice_notifier(&j1939_netdev_notifier);
+ fail_notifier:
+	return ret;
+}
+
+static __exit void j1939_module_exit(void)
+{
+	can_proto_unregister(&j1939_can_proto);
+
+	unregister_netdevice_notifier(&j1939_netdev_notifier);
+}
+
+module_init(j1939_module_init);
+module_exit(j1939_module_exit);