Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 917 insertions, 0 deletions

diff --git a/net/can/af_can.c b/net/can/af_can.c
new file mode 100644
index 0000000000..7343fd487d
--- /dev/null
+++ b/net/can/af_can.c
@@ -0,0 +1,917 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/* af_can.c - Protocol family CAN core module
+ *            (used by different CAN protocol modules)
+ *
+ * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Volkswagen nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * Alternatively, provided that this notice is retained in full, this
+ * software may be distributed under the terms of the GNU General
+ * Public License ("GPL") version 2, in which case the provisions of the
+ * GPL apply INSTEAD OF those given above.
+ *
+ * The provided data structures and external interfaces from this code
+ * are not restricted to be used by modules with a GPL compatible license.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/stddef.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/uaccess.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/socket.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <linux/can.h>
+#include <linux/can/core.h>
+#include <linux/can/skb.h>
+#include <linux/can/can-ml.h>
+#include <linux/ratelimit.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+
+#include "af_can.h"
+
+MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
+	      "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
+
+MODULE_ALIAS_NETPROTO(PF_CAN);
+
+static int stats_timer __read_mostly = 1;
+module_param(stats_timer, int, 0444);
+MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
+
+static struct kmem_cache *rcv_cache __read_mostly;
+
+/* table of registered CAN protocols */
+static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
+static DEFINE_MUTEX(proto_tab_lock);
+
+static atomic_t skbcounter = ATOMIC_INIT(0);
+
+/* af_can socket functions */
+
+void can_sock_destruct(struct sock *sk)
+{
+	skb_queue_purge(&sk->sk_receive_queue);
+	skb_queue_purge(&sk->sk_error_queue);
+}
+EXPORT_SYMBOL(can_sock_destruct);
+
+static const struct can_proto *can_get_proto(int protocol)
+{
+	const struct can_proto *cp;
+
+	rcu_read_lock();
+	cp = rcu_dereference(proto_tab[protocol]);
+	if (cp && !try_module_get(cp->prot->owner))
+		cp = NULL;
+	rcu_read_unlock();
+
+	return cp;
+}
+
+static inline void can_put_proto(const struct can_proto *cp)
+{
+	module_put(cp->prot->owner);
+}
+
+static int can_create(struct net *net, struct socket *sock, int protocol,
+		      int kern)
+{
+	struct sock *sk;
+	const struct can_proto *cp;
+	int err = 0;
+
+	sock->state = SS_UNCONNECTED;
+
+	if (protocol < 0 || protocol >= CAN_NPROTO)
+		return -EINVAL;
+
+	cp = can_get_proto(protocol);
+
+#ifdef CONFIG_MODULES
+	if (!cp) {
+		/* try to load protocol module if kernel is modular */
+
+		err = request_module("can-proto-%d", protocol);
+
+		/* In case of error we only print a message but don't
+		 * return the error code immediately.  Below we will
+		 * return -EPROTONOSUPPORT
+		 */
+		if (err)
+			pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n",
+					   protocol);
+
+		cp = can_get_proto(protocol);
+	}
+#endif
+
+	/* check for available protocol and correct usage */
+
+	if (!cp)
+		return -EPROTONOSUPPORT;
+
+	if (cp->type != sock->type) {
+		err = -EPROTOTYPE;
+		goto errout;
+	}
+
+	sock->ops = cp->ops;
+
+	sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
+	if (!sk) {
+		err = -ENOMEM;
+		goto errout;
+	}
+
+	sock_init_data(sock, sk);
+	sk->sk_destruct = can_sock_destruct;
+
+	if (sk->sk_prot->init)
+		err = sk->sk_prot->init(sk);
+
+	if (err) {
+		/* release sk on errors */
+		sock_orphan(sk);
+		sock_put(sk);
+	}
+
+ errout:
+	can_put_proto(cp);
+	return err;
+}
+
+/* af_can tx path */
+
+/**
+ * can_send - transmit a CAN frame (optional with local loopback)
+ * @skb: pointer to socket buffer with CAN frame in data section
+ * @loop: loopback for listeners on local CAN sockets (recommended default!)
+ *
+ * Due to the loopback this routine must not be called from hardirq context.
+ *
+ * Return:
+ *  0 on success
+ *  -ENETDOWN when the selected interface is down
+ *  -ENOBUFS on full driver queue (see net_xmit_errno())
+ *  -ENOMEM when local loopback failed at calling skb_clone()
+ *  -EPERM when trying to send on a non-CAN interface
+ *  -EMSGSIZE CAN frame size is bigger than CAN interface MTU
+ *  -EINVAL when the skb->data does not contain a valid CAN frame
+ */
+int can_send(struct sk_buff *skb, int loop)
+{
+	struct sk_buff *newskb = NULL;
+	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
+	int err = -EINVAL;
+
+	if (can_is_canxl_skb(skb)) {
+		skb->protocol = htons(ETH_P_CANXL);
+	} else if (can_is_can_skb(skb)) {
+		skb->protocol = htons(ETH_P_CAN);
+	} else if (can_is_canfd_skb(skb)) {
+		struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
+		skb->protocol = htons(ETH_P_CANFD);
+
+		/* set CAN FD flag for CAN FD frames by default */
+		cfd->flags |= CANFD_FDF;
+	} else {
+		goto inval_skb;
+	}
+
+	/* Make sure the CAN frame can pass the selected CAN netdevice. */
+	if (unlikely(skb->len > skb->dev->mtu)) {
+		err = -EMSGSIZE;
+		goto inval_skb;
+	}
+
+	if (unlikely(skb->dev->type != ARPHRD_CAN)) {
+		err = -EPERM;
+		goto inval_skb;
+	}
+
+	if (unlikely(!(skb->dev->flags & IFF_UP))) {
+		err = -ENETDOWN;
+		goto inval_skb;
+	}
+
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	if (loop) {
+		/* local loopback of sent CAN frames */
+
+		/* indication for the CAN driver: do loopback */
+		skb->pkt_type = PACKET_LOOPBACK;
+
+		/* The reference to the originating sock may be required
+		 * by the receiving socket to check whether the frame is
+		 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
+		 * Therefore we have to ensure that skb->sk remains the
+		 * reference to the originating sock by restoring skb->sk
+		 * after each skb_clone() or skb_orphan() usage.
+		 */
+
+		if (!(skb->dev->flags & IFF_ECHO)) {
+			/* If the interface is not capable to do loopback
+			 * itself, we do it here.
+			 */
+			newskb = skb_clone(skb, GFP_ATOMIC);
+			if (!newskb) {
+				kfree_skb(skb);
+				return -ENOMEM;
+			}
+
+			can_skb_set_owner(newskb, skb->sk);
+			newskb->ip_summed = CHECKSUM_UNNECESSARY;
+			newskb->pkt_type = PACKET_BROADCAST;
+		}
+	} else {
+		/* indication for the CAN driver: no loopback required */
+		skb->pkt_type = PACKET_HOST;
+	}
+
+	/* send to netdevice */
+	err = dev_queue_xmit(skb);
+	if (err > 0)
+		err = net_xmit_errno(err);
+
+	if (err) {
+		kfree_skb(newskb);
+		return err;
+	}
+
+	if (newskb)
+		netif_rx(newskb);
+
+	/* update statistics */
+	pkg_stats->tx_frames++;
+	pkg_stats->tx_frames_delta++;
+
+	return 0;
+
+inval_skb:
+	kfree_skb(skb);
+	return err;
+}
+EXPORT_SYMBOL(can_send);
+
+/* af_can rx path */
+
+static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
+							struct net_device *dev)
+{
+	if (dev) {
+		struct can_ml_priv *can_ml = can_get_ml_priv(dev);
+		return &can_ml->dev_rcv_lists;
+	} else {
+		return net->can.rx_alldev_list;
+	}
+}
+
+/**
+ * effhash - hash function for 29 bit CAN identifier reduction
+ * @can_id: 29 bit CAN identifier
+ *
+ * Description:
+ *  To reduce the linear traversal in one linked list of _single_ EFF CAN
+ *  frame subscriptions the 29 bit identifier is mapped to 10 bits.
+ *  (see CAN_EFF_RCV_HASH_BITS definition)
+ *
+ * Return:
+ *  Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
+ */
+static unsigned int effhash(canid_t can_id)
+{
+	unsigned int hash;
+
+	hash = can_id;
+	hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
+	hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
+
+	return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
+}
+
+/**
+ * can_rcv_list_find - determine optimal filterlist inside device filter struct
+ * @can_id: pointer to CAN identifier of a given can_filter
+ * @mask: pointer to CAN mask of a given can_filter
+ * @dev_rcv_lists: pointer to the device filter struct
+ *
+ * Description:
+ *  Returns the optimal filterlist to reduce the filter handling in the
+ *  receive path. This function is called by service functions that need
+ *  to register or unregister a can_filter in the filter lists.
+ *
+ *  A filter matches in general, when
+ *
+ *          <received_can_id> & mask == can_id & mask
+ *
+ *  so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
+ *  relevant bits for the filter.
+ *
+ *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
+ *  filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
+ *  frames there is a special filterlist and a special rx path filter handling.
+ *
+ * Return:
+ *  Pointer to optimal filterlist for the given can_id/mask pair.
+ *  Consistency checked mask.
+ *  Reduced can_id to have a preprocessed filter compare value.
+ */
+static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
+					    struct can_dev_rcv_lists *dev_rcv_lists)
+{
+	canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
+
+	/* filter for error message frames in extra filterlist */
+	if (*mask & CAN_ERR_FLAG) {
+		/* clear CAN_ERR_FLAG in filter entry */
+		*mask &= CAN_ERR_MASK;
+		return &dev_rcv_lists->rx[RX_ERR];
+	}
+
+	/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
+
+#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
+
+	/* ensure valid values in can_mask for 'SFF only' frame filtering */
+	if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
+		*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
+
+	/* reduce condition testing at receive time */
+	*can_id &= *mask;
+
+	/* inverse can_id/can_mask filter */
+	if (inv)
+		return &dev_rcv_lists->rx[RX_INV];
+
+	/* mask == 0 => no condition testing at receive time */
+	if (!(*mask))
+		return &dev_rcv_lists->rx[RX_ALL];
+
+	/* extra filterlists for the subscription of a single non-RTR can_id */
+	if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
+	    !(*can_id & CAN_RTR_FLAG)) {
+		if (*can_id & CAN_EFF_FLAG) {
+			if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
+				return &dev_rcv_lists->rx_eff[effhash(*can_id)];
+		} else {
+			if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
+				return &dev_rcv_lists->rx_sff[*can_id];
+		}
+	}
+
+	/* default: filter via can_id/can_mask */
+	return &dev_rcv_lists->rx[RX_FIL];
+}
+
+/**
+ * can_rx_register - subscribe CAN frames from a specific interface
+ * @net: the applicable net namespace
+ * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
+ * @can_id: CAN identifier (see description)
+ * @mask: CAN mask (see description)
+ * @func: callback function on filter match
+ * @data: returned parameter for callback function
+ * @ident: string for calling module identification
+ * @sk: socket pointer (might be NULL)
+ *
+ * Description:
+ *  Invokes the callback function with the received sk_buff and the given
+ *  parameter 'data' on a matching receive filter. A filter matches, when
+ *
+ *          <received_can_id> & mask == can_id & mask
+ *
+ *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
+ *  filter for error message frames (CAN_ERR_FLAG bit set in mask).
+ *
+ *  The provided pointer to the sk_buff is guaranteed to be valid as long as
+ *  the callback function is running. The callback function must *not* free
+ *  the given sk_buff while processing it's task. When the given sk_buff is
+ *  needed after the end of the callback function it must be cloned inside
+ *  the callback function with skb_clone().
+ *
+ * Return:
+ *  0 on success
+ *  -ENOMEM on missing cache mem to create subscription entry
+ *  -ENODEV unknown device
+ */
+int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
+		    canid_t mask, void (*func)(struct sk_buff *, void *),
+		    void *data, char *ident, struct sock *sk)
+{
+	struct receiver *rcv;
+	struct hlist_head *rcv_list;
+	struct can_dev_rcv_lists *dev_rcv_lists;
+	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
+
+	/* insert new receiver  (dev,canid,mask) -> (func,data) */
+
+	if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev)))
+		return -ENODEV;
+
+	if (dev && !net_eq(net, dev_net(dev)))
+		return -ENODEV;
+
+	rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
+	if (!rcv)
+		return -ENOMEM;
+
+	spin_lock_bh(&net->can.rcvlists_lock);
+
+	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
+	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
+
+	rcv->can_id = can_id;
+	rcv->mask = mask;
+	rcv->matches = 0;
+	rcv->func = func;
+	rcv->data = data;
+	rcv->ident = ident;
+	rcv->sk = sk;
+
+	hlist_add_head_rcu(&rcv->list, rcv_list);
+	dev_rcv_lists->entries++;
+
+	rcv_lists_stats->rcv_entries++;
+	rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
+					       rcv_lists_stats->rcv_entries);
+	spin_unlock_bh(&net->can.rcvlists_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(can_rx_register);
+
+/* can_rx_delete_receiver - rcu callback for single receiver entry removal */
+static void can_rx_delete_receiver(struct rcu_head *rp)
+{
+	struct receiver *rcv = container_of(rp, struct receiver, rcu);
+	struct sock *sk = rcv->sk;
+
+	kmem_cache_free(rcv_cache, rcv);
+	if (sk)
+		sock_put(sk);
+}
+
+/**
+ * can_rx_unregister - unsubscribe CAN frames from a specific interface
+ * @net: the applicable net namespace
+ * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
+ * @can_id: CAN identifier
+ * @mask: CAN mask
+ * @func: callback function on filter match
+ * @data: returned parameter for callback function
+ *
+ * Description:
+ *  Removes subscription entry depending on given (subscription) values.
+ */
+void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
+		       canid_t mask, void (*func)(struct sk_buff *, void *),
+		       void *data)
+{
+	struct receiver *rcv = NULL;
+	struct hlist_head *rcv_list;
+	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
+	struct can_dev_rcv_lists *dev_rcv_lists;
+
+	if (dev && dev->type != ARPHRD_CAN)
+		return;
+
+	if (dev && !net_eq(net, dev_net(dev)))
+		return;
+
+	spin_lock_bh(&net->can.rcvlists_lock);
+
+	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
+	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
+
+	/* Search the receiver list for the item to delete.  This should
+	 * exist, since no receiver may be unregistered that hasn't
+	 * been registered before.
+	 */
+	hlist_for_each_entry_rcu(rcv, rcv_list, list) {
+		if (rcv->can_id == can_id && rcv->mask == mask &&
+		    rcv->func == func && rcv->data == data)
+			break;
+	}
+
+	/* Check for bugs in CAN protocol implementations using af_can.c:
+	 * 'rcv' will be NULL if no matching list item was found for removal.
+	 * As this case may potentially happen when closing a socket while
+	 * the notifier for removing the CAN netdev is running we just print
+	 * a warning here.
+	 */
+	if (!rcv) {
+		pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
+			DNAME(dev), can_id, mask);
+		goto out;
+	}
+
+	hlist_del_rcu(&rcv->list);
+	dev_rcv_lists->entries--;
+
+	if (rcv_lists_stats->rcv_entries > 0)
+		rcv_lists_stats->rcv_entries--;
+
+ out:
+	spin_unlock_bh(&net->can.rcvlists_lock);
+
+	/* schedule the receiver item for deletion */
+	if (rcv) {
+		if (rcv->sk)
+			sock_hold(rcv->sk);
+		call_rcu(&rcv->rcu, can_rx_delete_receiver);
+	}
+}
+EXPORT_SYMBOL(can_rx_unregister);
+
+static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
+{
+	rcv->func(skb, rcv->data);
+	rcv->matches++;
+}
+
+static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
+{
+	struct receiver *rcv;
+	int matches = 0;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	canid_t can_id = cf->can_id;
+
+	if (dev_rcv_lists->entries == 0)
+		return 0;
+
+	if (can_id & CAN_ERR_FLAG) {
+		/* check for error message frame entries only */
+		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
+			if (can_id & rcv->mask) {
+				deliver(skb, rcv);
+				matches++;
+			}
+		}
+		return matches;
+	}
+
+	/* check for unfiltered entries */
+	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
+		deliver(skb, rcv);
+		matches++;
+	}
+
+	/* check for can_id/mask entries */
+	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
+		if ((can_id & rcv->mask) == rcv->can_id) {
+			deliver(skb, rcv);
+			matches++;
+		}
+	}
+
+	/* check for inverted can_id/mask entries */
+	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
+		if ((can_id & rcv->mask) != rcv->can_id) {
+			deliver(skb, rcv);
+			matches++;
+		}
+	}
+
+	/* check filterlists for single non-RTR can_ids */
+	if (can_id & CAN_RTR_FLAG)
+		return matches;
+
+	if (can_id & CAN_EFF_FLAG) {
+		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
+			if (rcv->can_id == can_id) {
+				deliver(skb, rcv);
+				matches++;
+			}
+		}
+	} else {
+		can_id &= CAN_SFF_MASK;
+		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
+			deliver(skb, rcv);
+			matches++;
+		}
+	}
+
+	return matches;
+}
+
+static void can_receive(struct sk_buff *skb, struct net_device *dev)
+{
+	struct can_dev_rcv_lists *dev_rcv_lists;
+	struct net *net = dev_net(dev);
+	struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
+	int matches;
+
+	/* update statistics */
+	pkg_stats->rx_frames++;
+	pkg_stats->rx_frames_delta++;
+
+	/* create non-zero unique skb identifier together with *skb */
+	while (!(can_skb_prv(skb)->skbcnt))
+		can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
+
+	rcu_read_lock();
+
+	/* deliver the packet to sockets listening on all devices */
+	matches = can_rcv_filter(net->can.rx_alldev_list, skb);
+
+	/* find receive list for this device */
+	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
+	matches += can_rcv_filter(dev_rcv_lists, skb);
+
+	rcu_read_unlock();
+
+	/* consume the skbuff allocated by the netdevice driver */
+	consume_skb(skb);
+
+	if (matches > 0) {
+		pkg_stats->matches++;
+		pkg_stats->matches_delta++;
+	}
+}
+
+static int can_rcv(struct sk_buff *skb, struct net_device *dev,
+		   struct packet_type *pt, struct net_device *orig_dev)
+{
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
+		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
+			     dev->type, skb->len);
+
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	can_receive(skb, dev);
+	return NET_RX_SUCCESS;
+}
+
+static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
+		     struct packet_type *pt, struct net_device *orig_dev)
+{
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
+		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
+			     dev->type, skb->len);
+
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	can_receive(skb, dev);
+	return NET_RX_SUCCESS;
+}
+
+static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
+		     struct packet_type *pt, struct net_device *orig_dev)
+{
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
+		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
+			     dev->type, skb->len);
+
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	can_receive(skb, dev);
+	return NET_RX_SUCCESS;
+}
+
+/* af_can protocol functions */
+
+/**
+ * can_proto_register - register CAN transport protocol
+ * @cp: pointer to CAN protocol structure
+ *
+ * Return:
+ *  0 on success
+ *  -EINVAL invalid (out of range) protocol number
+ *  -EBUSY  protocol already in use
+ *  -ENOBUF if proto_register() fails
+ */
+int can_proto_register(const struct can_proto *cp)
+{
+	int proto = cp->protocol;
+	int err = 0;
+
+	if (proto < 0 || proto >= CAN_NPROTO) {
+		pr_err("can: protocol number %d out of range\n", proto);
+		return -EINVAL;
+	}
+
+	err = proto_register(cp->prot, 0);
+	if (err < 0)
+		return err;
+
+	mutex_lock(&proto_tab_lock);
+
+	if (rcu_access_pointer(proto_tab[proto])) {
+		pr_err("can: protocol %d already registered\n", proto);
+		err = -EBUSY;
+	} else {
+		RCU_INIT_POINTER(proto_tab[proto], cp);
+	}
+
+	mutex_unlock(&proto_tab_lock);
+
+	if (err < 0)
+		proto_unregister(cp->prot);
+
+	return err;
+}
+EXPORT_SYMBOL(can_proto_register);
+
+/**
+ * can_proto_unregister - unregister CAN transport protocol
+ * @cp: pointer to CAN protocol structure
+ */
+void can_proto_unregister(const struct can_proto *cp)
+{
+	int proto = cp->protocol;
+
+	mutex_lock(&proto_tab_lock);
+	BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
+	RCU_INIT_POINTER(proto_tab[proto], NULL);
+	mutex_unlock(&proto_tab_lock);
+
+	synchronize_rcu();
+
+	proto_unregister(cp->prot);
+}
+EXPORT_SYMBOL(can_proto_unregister);
+
+static int can_pernet_init(struct net *net)
+{
+	spin_lock_init(&net->can.rcvlists_lock);
+	net->can.rx_alldev_list =
+		kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
+	if (!net->can.rx_alldev_list)
+		goto out;
+	net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
+	if (!net->can.pkg_stats)
+		goto out_free_rx_alldev_list;
+	net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
+	if (!net->can.rcv_lists_stats)
+		goto out_free_pkg_stats;
+
+	if (IS_ENABLED(CONFIG_PROC_FS)) {
+		/* the statistics are updated every second (timer triggered) */
+		if (stats_timer) {
+			timer_setup(&net->can.stattimer, can_stat_update,
+				    0);
+			mod_timer(&net->can.stattimer,
+				  round_jiffies(jiffies + HZ));
+		}
+		net->can.pkg_stats->jiffies_init = jiffies;
+		can_init_proc(net);
+	}
+
+	return 0;
+
+ out_free_pkg_stats:
+	kfree(net->can.pkg_stats);
+ out_free_rx_alldev_list:
+	kfree(net->can.rx_alldev_list);
+ out:
+	return -ENOMEM;
+}
+
+static void can_pernet_exit(struct net *net)
+{
+	if (IS_ENABLED(CONFIG_PROC_FS)) {
+		can_remove_proc(net);
+		if (stats_timer)
+			del_timer_sync(&net->can.stattimer);
+	}
+
+	kfree(net->can.rx_alldev_list);
+	kfree(net->can.pkg_stats);
+	kfree(net->can.rcv_lists_stats);
+}
+
+/* af_can module init/exit functions */
+
+static struct packet_type can_packet __read_mostly = {
+	.type = cpu_to_be16(ETH_P_CAN),
+	.func = can_rcv,
+};
+
+static struct packet_type canfd_packet __read_mostly = {
+	.type = cpu_to_be16(ETH_P_CANFD),
+	.func = canfd_rcv,
+};
+
+static struct packet_type canxl_packet __read_mostly = {
+	.type = cpu_to_be16(ETH_P_CANXL),
+	.func = canxl_rcv,
+};
+
+static const struct net_proto_family can_family_ops = {
+	.family = PF_CAN,
+	.create = can_create,
+	.owner  = THIS_MODULE,
+};
+
+static struct pernet_operations can_pernet_ops __read_mostly = {
+	.init = can_pernet_init,
+	.exit = can_pernet_exit,
+};
+
+static __init int can_init(void)
+{
+	int err;
+
+	/* check for correct padding to be able to use the structs similarly */
+	BUILD_BUG_ON(offsetof(struct can_frame, len) !=
+		     offsetof(struct canfd_frame, len) ||
+		     offsetof(struct can_frame, data) !=
+		     offsetof(struct canfd_frame, data));
+
+	pr_info("can: controller area network core\n");
+
+	rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
+				      0, 0, NULL);
+	if (!rcv_cache)
+		return -ENOMEM;
+
+	err = register_pernet_subsys(&can_pernet_ops);
+	if (err)
+		goto out_pernet;
+
+	/* protocol register */
+	err = sock_register(&can_family_ops);
+	if (err)
+		goto out_sock;
+
+	dev_add_pack(&can_packet);
+	dev_add_pack(&canfd_packet);
+	dev_add_pack(&canxl_packet);
+
+	return 0;
+
+out_sock:
+	unregister_pernet_subsys(&can_pernet_ops);
+out_pernet:
+	kmem_cache_destroy(rcv_cache);
+
+	return err;
+}
+
+static __exit void can_exit(void)
+{
+	/* protocol unregister */
+	dev_remove_pack(&canxl_packet);
+	dev_remove_pack(&canfd_packet);
+	dev_remove_pack(&can_packet);
+	sock_unregister(PF_CAN);
+
+	unregister_pernet_subsys(&can_pernet_ops);
+
+	rcu_barrier(); /* Wait for completion of call_rcu()'s */
+
+	kmem_cache_destroy(rcv_cache);
+}
+
+module_init(can_init);
+module_exit(can_exit);