[PATCH 5/7] CAN: Add virtual CAN netdevice driver

Urs Thuermann
2007-09-25T12:30:51Z

[-- Attachment #1: 05-can-vcan-driver.diff --]
[-- Type: text/plain, Size: 9148 bytes --]

This patch adds the virtual CAN bus (vcan) network driver.
The vcan device is just a loopback device for CAN frames, no
real CAN hardware is involved.

Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>

---
drivers/net/Makefile | 1
drivers/net/can/Kconfig | 25 +++++
drivers/net/can/Makefile | 5 +
drivers/net/can/vcan.c | 208 +++++++++++++++++++++++++++++++++++++++++++++++
net/can/Kconfig | 3
5 files changed, 242 insertions(+)

Index: net-2.6.24/drivers/net/Makefile
===================================================================
--- net-2.6.24.orig/drivers/net/Makefile 2007-09-25 13:28:42.000000000 +0200
+++ net-2.6.24/drivers/net/Makefile 2007-09-25 13:32:23.000000000 +0200
@@ -10,6 +10,7 @@
obj-$(CONFIG_CHELSIO_T1) += chelsio/
obj-$(CONFIG_CHELSIO_T3) += cxgb3/
obj-$(CONFIG_EHEA) += ehea/
+obj-$(CONFIG_CAN) += can/
obj-$(CONFIG_BONDING) += bonding/
obj-$(CONFIG_ATL1) += atl1/
obj-$(CONFIG_GIANFAR) += gianfar_driver.o
Index: net-2.6.24/drivers/net/can/Kconfig
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ net-2.6.24/drivers/net/can/Kconfig 2007-09-25 13:32:23.000000000 +0200
@@ -0,0 +1,25 @@
+menu "CAN Device Drivers"
+ depends on CAN
+
+config CAN_VCAN
+ tristate "Virtual Local CAN Interface (vcan)"
+ depends on CAN
+ default N
+ ---help---
+ Similar to the network loopback devices, vcan offers a
+ virtual local CAN interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called vcan.
+
+config CAN_DEBUG_DEVICES
+ bool "CAN devices debugging messages"
+ depends on CAN
+ default N
+ ---help---
+ Say Y here if you want the CAN device drivers to produce a bunch of
+ debug messages to the system log. Select this if you are having
+ a problem with CAN support and want to see more of what is going
+ on.
+
+endmenu
Index: net-2.6.24/drivers/net/can/Makefile
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ net-2.6.24/drivers/net/can/Makefile 2007-09-25 13:32:23.000000000 +0200
@@ -0,0 +1,5 @@
+#
+# Makefile for the Linux Controller Area Network drivers.
+#
+
+obj-$(CONFIG_CAN_VCAN) += vcan.o
Index: net-2.6.24/drivers/net/can/vcan.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ net-2.6.24/drivers/net/can/vcan.c 2007-09-25 13:32:23.000000000 +0200
@@ -0,0 +1,208 @@
+/*
+ * vcan.c - Virtual CAN interface
+ *
+ * Copyright (c) 2002-2007 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, the following disclaimer and
+ * the referenced file 'COPYING'.
+ * 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 as distributed in the 'COPYING'
+ * file from the main directory of the linux kernel source.
+ *
+ * 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.
+ *
+ * Send feedback to <socketcan-users@lists.berlios.de>
+ *
+ */
+
+#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 <net/rtnetlink.h>
+
+static __initdata const char banner[] =
+ KERN_INFO "vcan: Virtual CAN interface driver\n";
+
+MODULE_DESCRIPTION("virtual CAN interface");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
+
+#ifdef CONFIG_CAN_DEBUG_DEVICES
+static int debug;
+module_param(debug, int, S_IRUGO);
+#endif
+
+/* To be moved to linux/can/dev.h */
+#ifdef CONFIG_CAN_DEBUG_DEVICES
+#define DBG(fmt, args...) (debug & 1 ? \
+ printk(KERN_DEBUG "vcan %s: " fmt, \
+ __func__, ##args) : 0)
+#else
+#define DBG(fmt, args...)
+#endif
+
+
+/*
+ * CAN test feature:
+ * Enable the loopback on driver level for testing the CAN core loopback modes.
+ * See Documentation/networking/can.txt for details.
+ */
+
+static int loopback; /* loopback testing. Default: 0 (Off) */
+module_param(loopback, int, S_IRUGO);
+MODULE_PARM_DESC(loopback, "Loop back frames (for testing). Default: 0 (Off)");
+
+
+static int vcan_open(struct net_device *dev)
+{
+ DBG("%s: interface up\n", dev->name);
+
+ netif_start_queue(dev);
+ return 0;
+}
+
+static int vcan_stop(struct net_device *dev)
+{
+ DBG("%s: interface down\n", dev->name);
+
+ netif_stop_queue(dev);
+ return 0;
+}
+
+static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
+{
+ struct net_device_stats *stats = &dev->stats;
+
+ stats->rx_packets++;
+ stats->rx_bytes += skb->len;
+
+ skb->protocol = htons(ETH_P_CAN);
+ skb->pkt_type = PACKET_BROADCAST;
+ skb->dev = dev;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ DBG("received skbuff on interface %d\n", dev->ifindex);
+
+ netif_rx(skb);
+}
+
+static int vcan_tx(struct sk_buff *skb, struct net_device *dev)
+{
+ struct net_device_stats *stats = &dev->stats;
+ int loop;
+
+ DBG("sending skbuff on interface %s\n", dev->name);
+
+ stats->tx_packets++;
+ stats->tx_bytes += skb->len;
+
+ /* set flag whether this packet has to be looped back */
+ loop = skb->pkt_type == PACKET_LOOPBACK;
+
+ if (!loopback) {
+ /* no loopback handling available inside this driver */
+
+ if (loop) {
+ /*
+ * only count the packets here, because the
+ * CAN core already did the loopback for us
+ */
+ stats->rx_packets++;
+ stats->rx_bytes += skb->len;
+ }
+ kfree_skb(skb);
+ return 0;
+ }
+
+ /* perform standard loopback handling for CAN network interfaces */
+
+ if (loop) {
+ struct sock *srcsk = skb->sk;
+
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (!skb)
+ return 0;
+
+ /* receive with packet counting */
+ skb->sk = srcsk;
+ vcan_rx(skb, dev);
+ } else {
+ /* no looped packets => no counting */
+ kfree_skb(skb);
+ }
+ return 0;
+}
+
+static void vcan_setup(struct net_device *dev)
+{
+ DBG("dev %s\n", dev->name);
+
+ dev->type = ARPHRD_CAN;
+ dev->mtu = sizeof(struct can_frame);
+ 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 (loopback)
+ dev->flags |= IFF_LOOPBACK;
+
+ dev->open = vcan_open;
+ dev->stop = vcan_stop;
+ dev->hard_start_xmit = vcan_tx;
+ dev->destructor = free_netdev;
+}
+
+static struct rtnl_link_ops vcan_link_ops __read_mostly = {
+ .kind = "vcan",
+ .setup = vcan_setup,
+};
+
+static __init int vcan_init_module(void)
+{
+ printk(banner);
+
+ if (loopback)
+ printk(KERN_INFO "vcan: enabled loopback 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);
Index: net-2.6.24/net/can/Kconfig
===================================================================
--- net-2.6.24.orig/net/can/Kconfig 2007-09-25 13:32:23.000000000 +0200
+++ net-2.6.24/net/can/Kconfig 2007-09-25 13:32:23.000000000 +0200
@@ -47,3 +47,6 @@
Say Y here if you want the CAN core to produce a bunch of debug
messages to the system log. Select this if you are having a
problem with CAN support and want to see more of what is going on.
+
+
+source "drivers/net/can/Kconfig"

--