// 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/netdev_lock.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" */ struct sk_buff_head rx_queue; struct napi_struct napi;}; static LIST_HEAD(lapbeth_devices); static void lapbeth_connected(struct net_device *dev, int reason);static void lapbeth_disconnected(struct net_device *dev, int reason); /* ------------------------------------------------------------------------ */ /* 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, lockdep_rtnl_is_held()) { if (lapbeth->ethdev == dev) return lapbeth; } return NULL;} static __inline__ int dev_is_ethdev(struct net_device *dev){ return dev->type == ARPHRD_ETHER && !netdev_need_ops_lock(dev);} /* ------------------------------------------------------------------------ */ static int lapbeth_napi_poll(struct napi_struct *napi, int budget){ struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev, napi); struct sk_buff *skb; int processed = 0; for (; processed < budget; ++processed) { skb = skb_dequeue(&lapbeth->rx_queue); if (!skb) break; netif_receive_skb_core(skb); } if (processed < budget) napi_complete(napi); return processed;} /* 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; skb = skb_share_check(skb, GFP_ATOMIC); if (!skb) 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 */ err = lapb_data_received(lapbeth->axdev, skb); if (err != 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){ struct lapbethdev *lapbeth = netdev_priv(dev); 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); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi); return NET_RX_SUCCESS;} /* 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: err = lapb_connect_request(dev); if (err == LAPB_CONNECTED) lapbeth_connected(dev, LAPB_OK); else if (err != LAPB_OK) pr_err("lapb_connect_request error: %d\n", err); goto drop; case X25_IFACE_DISCONNECT: err = lapb_disconnect_request(dev); if (err == LAPB_NOTCONNECTED) lapbeth_disconnected(dev, LAPB_OK); else if (err != LAPB_OK) pr_err("lapb_disconnect_request err: %d\n", err); fallthrough; default: goto drop; } skb_pull(skb, 1); err = lapb_data_request(dev, skb); if (err != 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){ struct lapbethdev *lapbeth = netdev_priv(dev); unsigned char *ptr; struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); if (!skb) return; ptr = skb_put(skb, 1); *ptr = X25_IFACE_CONNECT; skb->protocol = x25_type_trans(skb, dev); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi);} static void lapbeth_disconnected(struct net_device *dev, int reason){ struct lapbethdev *lapbeth = netdev_priv(dev); unsigned char *ptr; struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); if (!skb) return; ptr = skb_put(skb, 1); *ptr = X25_IFACE_DISCONNECT; skb->protocol = x25_type_trans(skb, dev); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi);} /* Set AX.25 callsign */static int lapbeth_set_mac_address(struct net_device *dev, void *addr){ struct sockaddr *sa = addr; dev_addr_set(dev, sa->sa_data); 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; napi_enable(&lapbeth->napi); err = lapb_register(dev, &lapbeth_callbacks); if (err != LAPB_OK) { napi_disable(&lapbeth->napi); 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); err = lapb_unregister(dev); if (err != LAPB_OK) pr_err("lapb_unregister error: %d\n", err); napi_disable(&lapbeth->napi); 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){ netdev_lockdep_set_classes(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(); if (dev->type != ARPHRD_ETHER) return -EINVAL; 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); skb_queue_head_init(&lapbeth->rx_queue); netif_napi_add_weight(ndev, &lapbeth->napi, lapbeth_napi_poll, 16); 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 net_device *dev = netdev_notifier_info_to_dev(ptr); struct lapbethdev *lapbeth; if (dev_net(dev) != &init_net) return NOTIFY_DONE; lapbeth = lapbeth_get_x25_dev(dev); if (!dev_is_ethdev(dev) && !lapbeth) return NOTIFY_DONE; switch (event) { case NETDEV_UP: /* New ethernet device -> new LAPB interface */ if (!lapbeth) lapbeth_new_device(dev); break; case NETDEV_GOING_DOWN: /* ethernet device closes -> close LAPB interface */ if (lapbeth) dev_close(lapbeth->axdev); break; case NETDEV_UNREGISTER: /* ethernet device disappears -> remove LAPB interface */ if (lapbeth) lapbeth_free_device(lapbeth); break; case NETDEV_PRE_TYPE_CHANGE: /* Our underlying device type must not change. */ if (lapbeth) return NOTIFY_BAD; } 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){ int err;Lines 1–500 of 537. 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// 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/netdev_lock.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" */ struct sk_buff_head rx_queue; struct napi_struct napi; }; static LIST_HEAD(lapbeth_devices); static void lapbeth_connected(struct net_device *dev, int reason); static void lapbeth_disconnected(struct net_device *dev, int reason); /* ------------------------------------------------------------------------ */ /* 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, lockdep_rtnl_is_held()) { if (lapbeth->ethdev == dev) return lapbeth; } return NULL; } static __inline__ int dev_is_ethdev(struct net_device *dev) { return dev->type == ARPHRD_ETHER && !netdev_need_ops_lock(dev); } /* ------------------------------------------------------------------------ */ static int lapbeth_napi_poll(struct napi_struct *napi, int budget) { struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev, napi); struct sk_buff *skb; int processed = 0; for (; processed < budget; ++processed) { skb = skb_dequeue(&lapbeth->rx_queue); if (!skb) break; netif_receive_skb_core(skb); } if (processed < budget) napi_complete(napi); return processed; } /* 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; skb = skb_share_check(skb, GFP_ATOMIC); if (!skb) 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 */ err = lapb_data_received(lapbeth->axdev, skb); if (err != 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) { struct lapbethdev *lapbeth = netdev_priv(dev); 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); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi); return NET_RX_SUCCESS; } /* 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: err = lapb_connect_request(dev); if (err == LAPB_CONNECTED) lapbeth_connected(dev, LAPB_OK); else if (err != LAPB_OK) pr_err("lapb_connect_request error: %d\n", err); goto drop; case X25_IFACE_DISCONNECT: err = lapb_disconnect_request(dev); if (err == LAPB_NOTCONNECTED) lapbeth_disconnected(dev, LAPB_OK); else if (err != LAPB_OK) pr_err("lapb_disconnect_request err: %d\n", err); fallthrough; default: goto drop; } skb_pull(skb, 1); err = lapb_data_request(dev, skb); if (err != 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) { struct lapbethdev *lapbeth = netdev_priv(dev); unsigned char *ptr; struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); if (!skb) return; ptr = skb_put(skb, 1); *ptr = X25_IFACE_CONNECT; skb->protocol = x25_type_trans(skb, dev); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi); } static void lapbeth_disconnected(struct net_device *dev, int reason) { struct lapbethdev *lapbeth = netdev_priv(dev); unsigned char *ptr; struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); if (!skb) return; ptr = skb_put(skb, 1); *ptr = X25_IFACE_DISCONNECT; skb->protocol = x25_type_trans(skb, dev); skb_queue_tail(&lapbeth->rx_queue, skb); napi_schedule(&lapbeth->napi); } /* Set AX.25 callsign */ static int lapbeth_set_mac_address(struct net_device *dev, void *addr) { struct sockaddr *sa = addr; dev_addr_set(dev, sa->sa_data); 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; napi_enable(&lapbeth->napi); err = lapb_register(dev, &lapbeth_callbacks); if (err != LAPB_OK) { napi_disable(&lapbeth->napi); 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); err = lapb_unregister(dev); if (err != LAPB_OK) pr_err("lapb_unregister error: %d\n", err); napi_disable(&lapbeth->napi); 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) { netdev_lockdep_set_classes(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(); if (dev->type != ARPHRD_ETHER) return -EINVAL; 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); skb_queue_head_init(&lapbeth->rx_queue); netif_napi_add_weight(ndev, &lapbeth->napi, lapbeth_napi_poll, 16); 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 net_device *dev = netdev_notifier_info_to_dev(ptr); struct lapbethdev *lapbeth; if (dev_net(dev) != &init_net) return NOTIFY_DONE; lapbeth = lapbeth_get_x25_dev(dev); if (!dev_is_ethdev(dev) && !lapbeth) return NOTIFY_DONE; switch (event) { case NETDEV_UP: /* New ethernet device -> new LAPB interface */ if (!lapbeth) lapbeth_new_device(dev); break; case NETDEV_GOING_DOWN: /* ethernet device closes -> close LAPB interface */ if (lapbeth) dev_close(lapbeth->axdev); break; case NETDEV_UNREGISTER: /* ethernet device disappears -> remove LAPB interface */ if (lapbeth) lapbeth_free_device(lapbeth); break; case NETDEV_PRE_TYPE_CHANGE: /* Our underlying device type must not change. */ if (lapbeth) return NOTIFY_BAD; } 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) { int err;