--- /dev/null
+/*
+ * 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);
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff