/* * "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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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; /* 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: 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) { int err; if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { pr_err("lapb_register error: %d\n", err); return -ENODEV; } return 0; } static int lapbeth_close(struct net_device *dev) { int err; 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; 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 "); MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); MODULE_LICENSE("GPL");