| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * "LAPB via ethernet" driver release 001 |
| * |
| * This code REQUIRES 2.1.15 or higher/ NET3.038 |
| * |
| * 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 <linux/uaccess.h> |
| #include <linux/mm.h> |
| #include <linux/interrupt.h> |
| #include <linux/notifier.h> |
| #include <linux/stat.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#) */ |
| bool up; |
| spinlock_t up_lock; /* Protects "up" */ |
| }; |
| |
| 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_rcu; |
| spin_lock_bh(&lapbeth->up_lock); |
| if (!lapbeth->up) |
| 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: |
| spin_unlock_bh(&lapbeth->up_lock); |
| rcu_read_unlock(); |
| return 0; |
| drop_unlock: |
| kfree_skb(skb); |
| goto out; |
| drop_unlock_rcu: |
| rcu_read_unlock(); |
| drop: |
| kfree_skb(skb); |
| return 0; |
| } |
| |
| static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) |
| { |
| unsigned char *ptr; |
| |
| if (skb_cow(skb, 1)) { |
| kfree_skb(skb); |
| return NET_RX_DROP; |
| } |
| |
| skb_push(skb, 1); |
| |
| 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) |
| { |
| struct lapbethdev *lapbeth = netdev_priv(dev); |
| int err; |
| |
| spin_lock_bh(&lapbeth->up_lock); |
| if (!lapbeth->up) |
| goto drop; |
| |
| /* There should be a pseudo header of 1 byte added by upper layers. |
| * Check to make sure it is there before reading it. |
| */ |
| if (skb->len < 1) |
| 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: |
| spin_unlock_bh(&lapbeth->up_lock); |
| 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; |
| |
| 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; |
| |
| skb->protocol = htons(ETH_P_DEC); |
| |
| skb_reset_network_header(skb); |
| |
| 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) |
| { |
| struct lapbethdev *lapbeth = netdev_priv(dev); |
| int err; |
| |
| if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { |
| pr_err("lapb_register error: %d\n", err); |
| return -ENODEV; |
| } |
| |
| spin_lock_bh(&lapbeth->up_lock); |
| lapbeth->up = true; |
| spin_unlock_bh(&lapbeth->up_lock); |
| |
| return 0; |
| } |
| |
| static int lapbeth_close(struct net_device *dev) |
| { |
| struct lapbethdev *lapbeth = netdev_priv(dev); |
| int err; |
| |
| spin_lock_bh(&lapbeth->up_lock); |
| lapbeth->up = false; |
| spin_unlock_bh(&lapbeth->up_lock); |
| |
| 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->needs_free_netdev = true; |
| dev->type = ARPHRD_X25; |
| dev->hard_header_len = 0; |
| 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; |
| |
| /* When transmitting data: |
| * first this driver removes a pseudo header of 1 byte, |
| * then the lapb module prepends an LAPB header of at most 3 bytes, |
| * then this driver prepends a length field of 2 bytes, |
| * then the underlying Ethernet device prepends its own header. |
| */ |
| ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len |
| + dev->needed_headroom; |
| ndev->needed_tailroom = dev->needed_tailroom; |
| |
| lapbeth = netdev_priv(ndev); |
| lapbeth->axdev = ndev; |
| |
| dev_hold(dev); |
| lapbeth->ethdev = dev; |
| |
| lapbeth->up = false; |
| spin_lock_init(&lapbeth->up_lock); |
| |
| 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); |
| 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"); |