v4.19.13 snapshot.
diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
new file mode 100644
index 0000000..d200a5b
--- /dev/null
+++ b/drivers/net/can/vcan.c
@@ -0,0 +1,190 @@
+/*
+ * vcan.c - Virtual CAN interface
+ *
+ * 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/init.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/skb.h>
+#include <linux/slab.h>
+#include <net/rtnetlink.h>
+
+#define DRV_NAME "vcan"
+
+MODULE_DESCRIPTION("virtual CAN interface");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
+MODULE_ALIAS_RTNL_LINK(DRV_NAME);
+
+
+/*
+ * CAN test feature:
+ * Enable the echo on driver level for testing the CAN core echo modes.
+ * See Documentation/networking/can.rst for details.
+ */
+
+static bool echo; /* echo testing. Default: 0 (Off) */
+module_param(echo, bool, 0444);
+MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
+
+
+static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
+{
+ struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+ struct net_device_stats *stats = &dev->stats;
+
+ stats->rx_packets++;
+ stats->rx_bytes += cfd->len;
+
+ skb->pkt_type = PACKET_BROADCAST;
+ skb->dev = dev;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ netif_rx_ni(skb);
+}
+
+static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
+{
+ struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+ struct net_device_stats *stats = &dev->stats;
+ int loop;
+
+ if (can_dropped_invalid_skb(dev, skb))
+ return NETDEV_TX_OK;
+
+ stats->tx_packets++;
+ stats->tx_bytes += cfd->len;
+
+ /* set flag whether this packet has to be looped back */
+ loop = skb->pkt_type == PACKET_LOOPBACK;
+
+ if (!echo) {
+ /* no echo handling available inside this driver */
+
+ if (loop) {
+ /*
+ * only count the packets here, because the
+ * CAN core already did the echo for us
+ */
+ stats->rx_packets++;
+ stats->rx_bytes += cfd->len;
+ }
+ consume_skb(skb);
+ return NETDEV_TX_OK;
+ }
+
+ /* perform standard echo handling for CAN network interfaces */
+
+ if (loop) {
+
+ skb = can_create_echo_skb(skb);
+ if (!skb)
+ return NETDEV_TX_OK;
+
+ /* receive with packet counting */
+ vcan_rx(skb, dev);
+ } else {
+ /* no looped packets => no counting */
+ consume_skb(skb);
+ }
+ return NETDEV_TX_OK;
+}
+
+static int vcan_change_mtu(struct net_device *dev, int new_mtu)
+{
+ /* Do not allow changing the MTU while running */
+ if (dev->flags & IFF_UP)
+ return -EBUSY;
+
+ if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
+ return -EINVAL;
+
+ dev->mtu = new_mtu;
+ return 0;
+}
+
+static const struct net_device_ops vcan_netdev_ops = {
+ .ndo_start_xmit = vcan_tx,
+ .ndo_change_mtu = vcan_change_mtu,
+};
+
+static void vcan_setup(struct net_device *dev)
+{
+ dev->type = ARPHRD_CAN;
+ dev->mtu = CANFD_MTU;
+ dev->hard_header_len = 0;
+ dev->addr_len = 0;
+ dev->tx_queue_len = 0;
+ dev->flags = IFF_NOARP;
+
+ /* set flags according to driver capabilities */
+ if (echo)
+ dev->flags |= IFF_ECHO;
+
+ dev->netdev_ops = &vcan_netdev_ops;
+ dev->needs_free_netdev = true;
+}
+
+static struct rtnl_link_ops vcan_link_ops __read_mostly = {
+ .kind = DRV_NAME,
+ .setup = vcan_setup,
+};
+
+static __init int vcan_init_module(void)
+{
+ pr_info("vcan: Virtual CAN interface driver\n");
+
+ if (echo)
+ printk(KERN_INFO "vcan: enabled echo on driver level.\n");
+
+ return rtnl_link_register(&vcan_link_ops);
+}
+
+static __exit void vcan_cleanup_module(void)
+{
+ rtnl_link_unregister(&vcan_link_ops);
+}
+
+module_init(vcan_init_module);
+module_exit(vcan_cleanup_module);