--- /dev/null
+/*
+ * "LAPB via ethernet" driver release 001
+ *
+ * This code REQUIRES 2.1.15 or higher/ NET3.038
+ *
+ * This module:
+ * This module is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * This is a "pseudo" network driver to allow LAPB over Ethernet.
+ *
+ * This driver can use any ethernet destination address, and can be
+ * limited to accept frames from one dedicated ethernet card only.
+ *
+ * History
+ * LAPBETH 001 Jonathan Naylor Cloned from bpqether.c
+ * 2000-10-29 Henner Eisen lapb_data_indication() return status.
+ * 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <asm/uaccess.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/stat.h>
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <linux/lapb.h>
+#include <linux/init.h>
+
+#include <net/x25device.h>
+
+static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+
+/* If this number is made larger, check that the temporary string buffer
+ * in lapbeth_new_device is large enough to store the probe device name.*/
+#define MAXLAPBDEV 100
+
+struct lapbethdev {
+ struct list_head node;
+ struct net_device *ethdev; /* link to ethernet device */
+ struct net_device *axdev; /* lapbeth device (lapb#) */
+};
+
+static LIST_HEAD(lapbeth_devices);
+
+/* ------------------------------------------------------------------------ */
+
+/*
+ * Get the LAPB device for the ethernet device
+ */
+static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
+{
+ struct lapbethdev *lapbeth;
+
+ list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {
+ if (lapbeth->ethdev == dev)
+ return lapbeth;
+ }
+ return NULL;
+}
+
+static __inline__ int dev_is_ethdev(struct net_device *dev)
+{
+ return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
+}
+
+/* ------------------------------------------------------------------------ */
+
+/*
+ * Receive a LAPB frame via an ethernet interface.
+ */
+static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
+{
+ int len, err;
+ struct lapbethdev *lapbeth;
+
+ if (dev_net(dev) != &init_net)
+ goto drop;
+
+ if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
+ return NET_RX_DROP;
+
+ if (!pskb_may_pull(skb, 2))
+ goto drop;
+
+ rcu_read_lock();
+ lapbeth = lapbeth_get_x25_dev(dev);
+ if (!lapbeth)
+ goto drop_unlock;
+ if (!netif_running(lapbeth->axdev))
+ goto drop_unlock;
+
+ len = skb->data[0] + skb->data[1] * 256;
+ dev->stats.rx_packets++;
+ dev->stats.rx_bytes += len;
+
+ skb_pull(skb, 2); /* Remove the length bytes */
+ skb_trim(skb, len); /* Set the length of the data */
+
+ if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
+ printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
+ goto drop_unlock;
+ }
+out:
+ rcu_read_unlock();
+ return 0;
+drop_unlock:
+ kfree_skb(skb);
+ goto out;
+drop:
+ kfree_skb(skb);
+ return 0;
+}
+
+static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
+{
+ unsigned char *ptr;
+
+ skb_push(skb, 1);
+
+ if (skb_cow(skb, 1))
+ return NET_RX_DROP;
+
+ ptr = skb->data;
+ *ptr = X25_IFACE_DATA;
+
+ skb->protocol = x25_type_trans(skb, dev);
+ return netif_rx(skb);
+}
+
+/*
+ * Send a LAPB frame via an ethernet interface
+ */
+static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ int err;
+
+ /*
+ * Just to be *really* sure not to send anything if the interface
+ * is down, the ethernet device may have gone.
+ */
+ if (!netif_running(dev))
+ goto drop;
+
+ switch (skb->data[0]) {
+ case X25_IFACE_DATA:
+ break;
+ case X25_IFACE_CONNECT:
+ if ((err = lapb_connect_request(dev)) != LAPB_OK)
+ pr_err("lapb_connect_request error: %d\n", err);
+ goto drop;
+ case X25_IFACE_DISCONNECT:
+ if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
+ pr_err("lapb_disconnect_request err: %d\n", err);
+ /* Fall thru */
+ default:
+ goto drop;
+ }
+
+ skb_pull(skb, 1);
+
+ if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
+ pr_err("lapb_data_request error - %d\n", err);
+ goto drop;
+ }
+out:
+ return NETDEV_TX_OK;
+drop:
+ kfree_skb(skb);
+ goto out;
+}
+
+static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
+{
+ struct lapbethdev *lapbeth = netdev_priv(ndev);
+ unsigned char *ptr;
+ struct net_device *dev;
+ int size = skb->len;
+
+ skb->protocol = htons(ETH_P_X25);
+
+ ptr = skb_push(skb, 2);
+
+ *ptr++ = size % 256;
+ *ptr++ = size / 256;
+
+ ndev->stats.tx_packets++;
+ ndev->stats.tx_bytes += size;
+
+ skb->dev = dev = lapbeth->ethdev;
+
+ dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
+
+ dev_queue_xmit(skb);
+}
+
+static void lapbeth_connected(struct net_device *dev, int reason)
+{
+ unsigned char *ptr;
+ struct sk_buff *skb = dev_alloc_skb(1);
+
+ if (!skb) {
+ pr_err("out of memory\n");
+ return;
+ }
+
+ ptr = skb_put(skb, 1);
+ *ptr = X25_IFACE_CONNECT;
+
+ skb->protocol = x25_type_trans(skb, dev);
+ netif_rx(skb);
+}
+
+static void lapbeth_disconnected(struct net_device *dev, int reason)
+{
+ unsigned char *ptr;
+ struct sk_buff *skb = dev_alloc_skb(1);
+
+ if (!skb) {
+ pr_err("out of memory\n");
+ return;
+ }
+
+ ptr = skb_put(skb, 1);
+ *ptr = X25_IFACE_DISCONNECT;
+
+ skb->protocol = x25_type_trans(skb, dev);
+ netif_rx(skb);
+}
+
+/*
+ * Set AX.25 callsign
+ */
+static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
+{
+ struct sockaddr *sa = addr;
+ memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
+ return 0;
+}
+
+
+static const struct lapb_register_struct lapbeth_callbacks = {
+ .connect_confirmation = lapbeth_connected,
+ .connect_indication = lapbeth_connected,
+ .disconnect_confirmation = lapbeth_disconnected,
+ .disconnect_indication = lapbeth_disconnected,
+ .data_indication = lapbeth_data_indication,
+ .data_transmit = lapbeth_data_transmit,
+};
+
+/*
+ * open/close a device
+ */
+static int lapbeth_open(struct net_device *dev)
+{
+ int err;
+
+ if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
+ pr_err("lapb_register error: %d\n", err);
+ return -ENODEV;
+ }
+
+ netif_start_queue(dev);
+ return 0;
+}
+
+static int lapbeth_close(struct net_device *dev)
+{
+ int err;
+
+ netif_stop_queue(dev);
+
+ if ((err = lapb_unregister(dev)) != LAPB_OK)
+ pr_err("lapb_unregister error: %d\n", err);
+
+ return 0;
+}
+
+/* ------------------------------------------------------------------------ */
+
+static const struct net_device_ops lapbeth_netdev_ops = {
+ .ndo_open = lapbeth_open,
+ .ndo_stop = lapbeth_close,
+ .ndo_start_xmit = lapbeth_xmit,
+ .ndo_set_mac_address = lapbeth_set_mac_address,
+};
+
+static void lapbeth_setup(struct net_device *dev)
+{
+ dev->netdev_ops = &lapbeth_netdev_ops;
+ dev->destructor = free_netdev;
+ dev->type = ARPHRD_X25;
+ dev->hard_header_len = 3;
+ dev->mtu = 1000;
+ dev->addr_len = 0;
+}
+
+/*
+ * Setup a new device.
+ */
+static int lapbeth_new_device(struct net_device *dev)
+{
+ struct net_device *ndev;
+ struct lapbethdev *lapbeth;
+ int rc = -ENOMEM;
+
+ ASSERT_RTNL();
+
+ ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN,
+ lapbeth_setup);
+ if (!ndev)
+ goto out;
+
+ lapbeth = netdev_priv(ndev);
+ lapbeth->axdev = ndev;
+
+ dev_hold(dev);
+ lapbeth->ethdev = dev;
+
+ rc = -EIO;
+ if (register_netdevice(ndev))
+ goto fail;
+
+ list_add_rcu(&lapbeth->node, &lapbeth_devices);
+ rc = 0;
+out:
+ return rc;
+fail:
+ dev_put(dev);
+ free_netdev(ndev);
+ kfree(lapbeth);
+ goto out;
+}
+
+/*
+ * Free a lapb network device.
+ */
+static void lapbeth_free_device(struct lapbethdev *lapbeth)
+{
+ dev_put(lapbeth->ethdev);
+ list_del_rcu(&lapbeth->node);
+ unregister_netdevice(lapbeth->axdev);
+}
+
+/*
+ * Handle device status changes.
+ *
+ * Called from notifier with RTNL held.
+ */
+static int lapbeth_device_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct lapbethdev *lapbeth;
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+ if (dev_net(dev) != &init_net)
+ return NOTIFY_DONE;
+
+ if (!dev_is_ethdev(dev))
+ return NOTIFY_DONE;
+
+ switch (event) {
+ case NETDEV_UP:
+ /* New ethernet device -> new LAPB interface */
+ if (lapbeth_get_x25_dev(dev) == NULL)
+ lapbeth_new_device(dev);
+ break;
+ case NETDEV_DOWN:
+ /* ethernet device closed -> close LAPB interface */
+ lapbeth = lapbeth_get_x25_dev(dev);
+ if (lapbeth)
+ dev_close(lapbeth->axdev);
+ break;
+ case NETDEV_UNREGISTER:
+ /* ethernet device disappears -> remove LAPB interface */
+ lapbeth = lapbeth_get_x25_dev(dev);
+ if (lapbeth)
+ lapbeth_free_device(lapbeth);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+/* ------------------------------------------------------------------------ */
+
+static struct packet_type lapbeth_packet_type __read_mostly = {
+ .type = cpu_to_be16(ETH_P_DEC),
+ .func = lapbeth_rcv,
+};
+
+static struct notifier_block lapbeth_dev_notifier = {
+ .notifier_call = lapbeth_device_event,
+};
+
+static const char banner[] __initconst =
+ KERN_INFO "LAPB Ethernet driver version 0.02\n";
+
+static int __init lapbeth_init_driver(void)
+{
+ dev_add_pack(&lapbeth_packet_type);
+
+ register_netdevice_notifier(&lapbeth_dev_notifier);
+
+ printk(banner);
+
+ return 0;
+}
+module_init(lapbeth_init_driver);
+
+static void __exit lapbeth_cleanup_driver(void)
+{
+ struct lapbethdev *lapbeth;
+ struct list_head *entry, *tmp;
+
+ dev_remove_pack(&lapbeth_packet_type);
+ unregister_netdevice_notifier(&lapbeth_dev_notifier);
+
+ rtnl_lock();
+ list_for_each_safe(entry, tmp, &lapbeth_devices) {
+ lapbeth = list_entry(entry, struct lapbethdev, node);
+
+ dev_put(lapbeth->ethdev);
+ unregister_netdevice(lapbeth->axdev);
+ }
+ rtnl_unlock();
+}
+module_exit(lapbeth_cleanup_driver);
+
+MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
+MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff