diff options
| -rw-r--r-- | drivers/net/can/Kconfig | 18 | ||||
| -rw-r--r-- | drivers/net/can/Makefile | 1 | ||||
| -rw-r--r-- | drivers/net/can/vxcan.c | 316 | ||||
| -rw-r--r-- | include/uapi/linux/can/vxcan.h | 12 |
4 files changed, 347 insertions, 0 deletions
diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig index aa20b69d2a1a..ac4ff394bc56 100644 --- a/drivers/net/can/Kconfig +++ b/drivers/net/can/Kconfig @@ -9,6 +9,24 @@ config CAN_VCAN This driver can also be built as a module. If so, the module will be called vcan. +config CAN_VXCAN + tristate "Virtual CAN Tunnel (vxcan)" + ---help--- + Similar to the virtual ethernet driver veth, vxcan implements a + local CAN traffic tunnel between two virtual CAN network devices. + When creating a vxcan, two vxcan devices are created as pair. + When one end receives the packet it appears on its pair and vice + versa. The vxcan can be used for cross namespace communication. + + In opposite to vcan loopback devices the vxcan only forwards CAN + frames to its pair and does *not* provide a local echo of sent + CAN frames. To disable a potential echo in af_can.c the vxcan driver + announces IFF_ECHO in the interface flags. To have a clean start + in each namespace the CAN GW hop counter is set to zero. + + This driver can also be built as a module. If so, the module + will be called vxcan. + config CAN_SLCAN tristate "Serial / USB serial CAN Adaptors (slcan)" depends on TTY diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile index 8581e2b3e87f..4aabbee133b8 100644 --- a/drivers/net/can/Makefile +++ b/drivers/net/can/Makefile @@ -3,6 +3,7 @@ # obj-$(CONFIG_CAN_VCAN) += vcan.o +obj-$(CONFIG_CAN_VXCAN) += vxcan.o obj-$(CONFIG_CAN_SLCAN) += slcan.o obj-$(CONFIG_CAN_DEV) += can-dev.o diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c new file mode 100644 index 000000000000..7fbb24795681 --- /dev/null +++ b/drivers/net/can/vxcan.c @@ -0,0 +1,316 @@ +/* + * vxcan.c - Virtual CAN Tunnel for cross namespace communication + * + * This code is derived from drivers/net/can/vcan.c for the virtual CAN + * specific parts and from drivers/net/veth.c to implement the netlink API + * for network interface pairs in a common and established way. + * + * Copyright (c) 2017 Oliver Hartkopp <socketcan@hartkopp.net> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the version 2 of the GNU General Public License + * as published by the Free Software Foundation + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#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/can/vxcan.h> +#include <linux/slab.h> +#include <net/rtnetlink.h> + +#define DRV_NAME "vxcan" + +MODULE_DESCRIPTION("Virtual CAN Tunnel"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>"); +MODULE_ALIAS_RTNL_LINK(DRV_NAME); + +struct vxcan_priv { + struct net_device __rcu *peer; +}; + +static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct vxcan_priv *priv = netdev_priv(dev); + struct net_device *peer; + struct canfd_frame *cfd = (struct canfd_frame *)skb->data; + struct net_device_stats *peerstats, *srcstats = &dev->stats; + + if (can_dropped_invalid_skb(dev, skb)) + return NETDEV_TX_OK; + + rcu_read_lock(); + peer = rcu_dereference(priv->peer); + if (unlikely(!peer)) { + kfree_skb(skb); + dev->stats.tx_dropped++; + goto out_unlock; + } + + skb = can_create_echo_skb(skb); + if (!skb) + goto out_unlock; + + /* reset CAN GW hop counter */ + skb->csum_start = 0; + skb->pkt_type = PACKET_BROADCAST; + skb->dev = peer; + skb->ip_summed = CHECKSUM_UNNECESSARY; + + if (netif_rx_ni(skb) == NET_RX_SUCCESS) { + srcstats->tx_packets++; + srcstats->tx_bytes += cfd->len; + peerstats = &peer->stats; + peerstats->rx_packets++; + peerstats->rx_bytes += cfd->len; + } + +out_unlock: + rcu_read_unlock(); + return NETDEV_TX_OK; +} + + +static int vxcan_open(struct net_device *dev) +{ + struct vxcan_priv *priv = netdev_priv(dev); + struct net_device *peer = rtnl_dereference(priv->peer); + + if (!peer) + return -ENOTCONN; + + if (peer->flags & IFF_UP) { + netif_carrier_on(dev); + netif_carrier_on(peer); + } + return 0; +} + +static int vxcan_close(struct net_device *dev) +{ + struct vxcan_priv *priv = netdev_priv(dev); + struct net_device *peer = rtnl_dereference(priv->peer); + + netif_carrier_off(dev); + if (peer) + netif_carrier_off(peer); + + return 0; +} + +static int vxcan_get_iflink(const struct net_device *dev) +{ + struct vxcan_priv *priv = netdev_priv(dev); + struct net_device *peer; + int iflink; + + rcu_read_lock(); + peer = rcu_dereference(priv->peer); + iflink = peer ? peer->ifindex : 0; + rcu_read_unlock(); + + return iflink; +} + +static int vxcan_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 vxcan_netdev_ops = { + .ndo_open = vxcan_open, + .ndo_stop = vxcan_close, + .ndo_start_xmit = vxcan_xmit, + .ndo_get_iflink = vxcan_get_iflink, + .ndo_change_mtu = vxcan_change_mtu, +}; + +static void vxcan_setup(struct net_device *dev) +{ + dev->type = ARPHRD_CAN; + dev->mtu = CAN_MTU; + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->tx_queue_len = 0; + dev->flags = (IFF_NOARP|IFF_ECHO); + dev->netdev_ops = &vxcan_netdev_ops; + dev->destructor = free_netdev; +} + +/* forward declaration for rtnl_create_link() */ +static struct rtnl_link_ops vxcan_link_ops; + +static int vxcan_newlink(struct net *net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[]) +{ + struct vxcan_priv *priv; + struct net_device *peer; + struct net *peer_net; + + struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb; + char ifname[IFNAMSIZ]; + unsigned char name_assign_type; + struct ifinfomsg *ifmp = NULL; + int err; + + /* register peer device */ + if (data && data[VXCAN_INFO_PEER]) { + struct nlattr *nla_peer; + + nla_peer = data[VXCAN_INFO_PEER]; + ifmp = nla_data(nla_peer); + err = rtnl_nla_parse_ifla(peer_tb, + nla_data(nla_peer) + + sizeof(struct ifinfomsg), + nla_len(nla_peer) - + sizeof(struct ifinfomsg), + NULL); + if (err < 0) + return err; + + tbp = peer_tb; + } + + if (tbp[IFLA_IFNAME]) { + nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ); + name_assign_type = NET_NAME_USER; + } else { + snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d"); + name_assign_type = NET_NAME_ENUM; + } + + peer_net = rtnl_link_get_net(net, tbp); + if (IS_ERR(peer_net)) + return PTR_ERR(peer_net); + + peer = rtnl_create_link(peer_net, ifname, name_assign_type, + &vxcan_link_ops, tbp); + if (IS_ERR(peer)) { + put_net(peer_net); + return PTR_ERR(peer); + } + + if (ifmp && dev->ifindex) + peer->ifindex = ifmp->ifi_index; + + err = register_netdevice(peer); + put_net(peer_net); + peer_net = NULL; + if (err < 0) { + free_netdev(peer); + return err; + } + + netif_carrier_off(peer); + + err = rtnl_configure_link(peer, ifmp); + if (err < 0) { + unregister_netdevice(peer); + return err; + } + + /* register first device */ + if (tb[IFLA_IFNAME]) + nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ); + else + snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d"); + + err = register_netdevice(dev); + if (err < 0) { + unregister_netdevice(peer); + return err; + } + + netif_carrier_off(dev); + + /* cross link the device pair */ + priv = netdev_priv(dev); + rcu_assign_pointer(priv->peer, peer); + + priv = netdev_priv(peer); + rcu_assign_pointer(priv->peer, dev); + + return 0; +} + +static void vxcan_dellink(struct net_device *dev, struct list_head *head) +{ + struct vxcan_priv *priv; + struct net_device *peer; + + priv = netdev_priv(dev); + peer = rtnl_dereference(priv->peer); + + /* Note : dellink() is called from default_device_exit_batch(), + * before a rcu_synchronize() point. The devices are guaranteed + * not being freed before one RCU grace period. + */ + RCU_INIT_POINTER(priv->peer, NULL); + unregister_netdevice_queue(dev, head); + + if (peer) { + priv = netdev_priv(peer); + RCU_INIT_POINTER(priv->peer, NULL); + unregister_netdevice_queue(peer, head); + } +} + +static const struct nla_policy vxcan_policy[VXCAN_INFO_MAX + 1] = { + [VXCAN_INFO_PEER] = { .len = sizeof(struct ifinfomsg) }, +}; + +static struct net *vxcan_get_link_net(const struct net_device *dev) +{ + struct vxcan_priv *priv = netdev_priv(dev); + struct net_device *peer = rtnl_dereference(priv->peer); + + return peer ? dev_net(peer) : dev_net(dev); +} + +static struct rtnl_link_ops vxcan_link_ops = { + .kind = DRV_NAME, + .priv_size = sizeof(struct vxcan_priv), + .setup = vxcan_setup, + .newlink = vxcan_newlink, + .dellink = vxcan_dellink, + .policy = vxcan_policy, + .maxtype = VXCAN_INFO_MAX, + .get_link_net = vxcan_get_link_net, +}; + +static __init int vxcan_init(void) +{ + pr_info("vxcan: Virtual CAN Tunnel driver\n"); + + return rtnl_link_register(&vxcan_link_ops); +} + +static __exit void vxcan_exit(void) +{ + rtnl_link_unregister(&vxcan_link_ops); +} + +module_init(vxcan_init); +module_exit(vxcan_exit); diff --git a/include/uapi/linux/can/vxcan.h b/include/uapi/linux/can/vxcan.h new file mode 100644 index 000000000000..ffb0b7156f7e --- /dev/null +++ b/include/uapi/linux/can/vxcan.h @@ -0,0 +1,12 @@ +#ifndef _UAPI_CAN_VXCAN_H +#define _UAPI_CAN_VXCAN_H + +enum { + VXCAN_INFO_UNSPEC, + VXCAN_INFO_PEER, + + __VXCAN_INFO_MAX +#define VXCAN_INFO_MAX (__VXCAN_INFO_MAX - 1) +}; + +#endif |