--- /dev/null
+/*
+ * G8BPQ compatible "AX.25 via ethernet" driver release 004
+ *
+ * This code REQUIRES 2.0.0 or higher/ NET3.029
+ *
+ * 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 AX.25 over Ethernet
+ * using G8BPQ encapsulation. It has been extracted from the protocol
+ * implementation because
+ *
+ * - things got unreadable within the protocol stack
+ * - to cure the protocol stack from "feature-ism"
+ * - a protocol implementation shouldn't need to know on
+ * which hardware it is running
+ * - user-level programs like the AX.25 utilities shouldn't
+ * need to know about the hardware.
+ * - IP over ethernet encapsulated AX.25 was impossible
+ * - rxecho.c did not work
+ * - to have room for extensions
+ * - it just deserves to "live" as an own driver
+ *
+ * This driver can use any ethernet destination address, and can be
+ * limited to accept frames from one dedicated ethernet card only.
+ *
+ * Note that the driver sets up the BPQ devices automagically on
+ * startup or (if started before the "insmod" of an ethernet device)
+ * on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
+ * the ethernet device (in fact: as soon as another ethernet or bpq
+ * device gets "ifconfig"ured).
+ *
+ * I have heard that several people are thinking of experiments
+ * with highspeed packet radio using existing ethernet cards.
+ * Well, this driver is prepared for this purpose, just add
+ * your tx key control and a txdelay / tailtime algorithm,
+ * probably some buffering, and /voila/...
+ *
+ * History
+ * BPQ 001 Joerg(DL1BKE) Extracted BPQ code from AX.25
+ * protocol stack and added my own
+ * yet existing patches
+ * BPQ 002 Joerg(DL1BKE) Scan network device list on
+ * startup.
+ * BPQ 003 Joerg(DL1BKE) Ethernet destination address
+ * and accepted source address
+ * can be configured by an ioctl()
+ * call.
+ * Fixed to match Linux networking
+ * changes - 2.1.15.
+ * BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.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/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtnetlink.h>
+
+#include <net/ip.h>
+#include <net/arp.h>
+#include <net/net_namespace.h>
+
+#include <linux/bpqether.h>
+
+static const char banner[] __initconst = KERN_INFO \
+ "AX.25: bpqether driver version 004\n";
+
+static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
+
+static char bpq_eth_addr[6];
+
+static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
+static int bpq_device_event(struct notifier_block *, unsigned long, void *);
+
+static struct packet_type bpq_packet_type __read_mostly = {
+ .type = cpu_to_be16(ETH_P_BPQ),
+ .func = bpq_rcv,
+};
+
+static struct notifier_block bpq_dev_notifier = {
+ .notifier_call = bpq_device_event,
+};
+
+
+struct bpqdev {
+ struct list_head bpq_list; /* list of bpq devices chain */
+ struct net_device *ethdev; /* link to ethernet device */
+ struct net_device *axdev; /* bpq device (bpq#) */
+ char dest_addr[6]; /* ether destination address */
+ char acpt_addr[6]; /* accept ether frames from this address only */
+};
+
+static LIST_HEAD(bpq_devices);
+
+/*
+ * bpqether network devices are paired with ethernet devices below them, so
+ * form a special "super class" of normal ethernet devices; split their locks
+ * off into a separate class since they always nest.
+ */
+static struct lock_class_key bpq_netdev_xmit_lock_key;
+static struct lock_class_key bpq_netdev_addr_lock_key;
+
+static void bpq_set_lockdep_class_one(struct net_device *dev,
+ struct netdev_queue *txq,
+ void *_unused)
+{
+ lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
+}
+
+static void bpq_set_lockdep_class(struct net_device *dev)
+{
+ lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
+ netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
+}
+
+/* ------------------------------------------------------------------------ */
+
+
+/*
+ * Get the ethernet device for a BPQ device
+ */
+static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
+{
+ struct bpqdev *bpq = netdev_priv(dev);
+
+ return bpq ? bpq->ethdev : NULL;
+}
+
+/*
+ * Get the BPQ device for the ethernet device
+ */
+static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
+{
+ struct bpqdev *bpq;
+
+ list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
+ if (bpq->ethdev == dev)
+ return bpq->axdev;
+ }
+ return NULL;
+}
+
+static inline int dev_is_ethdev(struct net_device *dev)
+{
+ return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
+}
+
+/* ------------------------------------------------------------------------ */
+
+
+/*
+ * Receive an AX.25 frame via an ethernet interface.
+ */
+static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
+{
+ int len;
+ char * ptr;
+ struct ethhdr *eth;
+ struct bpqdev *bpq;
+
+ if (!net_eq(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, sizeof(struct ethhdr)))
+ goto drop;
+
+ rcu_read_lock();
+ dev = bpq_get_ax25_dev(dev);
+
+ if (dev == NULL || !netif_running(dev))
+ goto drop_unlock;
+
+ /*
+ * if we want to accept frames from just one ethernet device
+ * we check the source address of the sender.
+ */
+
+ bpq = netdev_priv(dev);
+
+ eth = eth_hdr(skb);
+
+ if (!(bpq->acpt_addr[0] & 0x01) &&
+ !ether_addr_equal(eth->h_source, bpq->acpt_addr))
+ goto drop_unlock;
+
+ if (skb_cow(skb, sizeof(struct ethhdr)))
+ goto drop_unlock;
+
+ len = skb->data[0] + skb->data[1] * 256 - 5;
+
+ skb_pull(skb, 2); /* Remove the length bytes */
+ skb_trim(skb, len); /* Set the length of the data */
+
+ dev->stats.rx_packets++;
+ dev->stats.rx_bytes += len;
+
+ ptr = skb_push(skb, 1);
+ *ptr = 0;
+
+ skb->protocol = ax25_type_trans(skb, dev);
+ netif_rx(skb);
+unlock:
+
+ rcu_read_unlock();
+
+ return 0;
+drop_unlock:
+ kfree_skb(skb);
+ goto unlock;
+
+drop:
+ kfree_skb(skb);
+ return 0;
+}
+
+/*
+ * Send an AX.25 frame via an ethernet interface
+ */
+static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ unsigned char *ptr;
+ struct bpqdev *bpq;
+ struct net_device *orig_dev;
+ int size;
+
+ if (skb->protocol == htons(ETH_P_IP))
+ return ax25_ip_xmit(skb);
+
+ /*
+ * Just to be *really* sure not to send anything if the interface
+ * is down, the ethernet device may have gone.
+ */
+ if (!netif_running(dev)) {
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+
+ skb_pull(skb, 1); /* Drop KISS byte */
+ size = skb->len;
+
+ /*
+ * We're about to mess with the skb which may still shared with the
+ * generic networking code so unshare and ensure it's got enough
+ * space for the BPQ headers.
+ */
+ if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
+ if (net_ratelimit())
+ pr_err("bpqether: out of memory\n");
+ kfree_skb(skb);
+
+ return NETDEV_TX_OK;
+ }
+
+ ptr = skb_push(skb, 2); /* Make space for length */
+
+ *ptr++ = (size + 5) % 256;
+ *ptr++ = (size + 5) / 256;
+
+ bpq = netdev_priv(dev);
+
+ orig_dev = dev;
+ if ((dev = bpq_get_ether_dev(dev)) == NULL) {
+ orig_dev->stats.tx_dropped++;
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+
+ skb->protocol = ax25_type_trans(skb, dev);
+ skb_reset_network_header(skb);
+ dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
+ dev->stats.tx_packets++;
+ dev->stats.tx_bytes+=skb->len;
+
+ dev_queue_xmit(skb);
+ netif_wake_queue(dev);
+ return NETDEV_TX_OK;
+}
+
+/*
+ * Set AX.25 callsign
+ */
+static int bpq_set_mac_address(struct net_device *dev, void *addr)
+{
+ struct sockaddr *sa = (struct sockaddr *)addr;
+
+ memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
+
+ return 0;
+}
+
+/* Ioctl commands
+ *
+ * SIOCSBPQETHOPT reserved for enhancements
+ * SIOCSBPQETHADDR set the destination and accepted
+ * source ethernet address (broadcast
+ * or multicast: accept all)
+ */
+static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+ struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
+ struct bpqdev *bpq = netdev_priv(dev);
+ struct bpq_req req;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ switch (cmd) {
+ case SIOCSBPQETHOPT:
+ if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
+ return -EFAULT;
+ switch (req.cmd) {
+ case SIOCGBPQETHPARAM:
+ case SIOCSBPQETHPARAM:
+ default:
+ return -EINVAL;
+ }
+
+ break;
+
+ case SIOCSBPQETHADDR:
+ if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
+ return -EFAULT;
+ if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
+ return -EFAULT;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * open/close a device
+ */
+static int bpq_open(struct net_device *dev)
+{
+ netif_start_queue(dev);
+ return 0;
+}
+
+static int bpq_close(struct net_device *dev)
+{
+ netif_stop_queue(dev);
+ return 0;
+}
+
+
+/* ------------------------------------------------------------------------ */
+
+
+/*
+ * Proc filesystem
+ */
+static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
+ __acquires(RCU)
+{
+ int i = 1;
+ struct bpqdev *bpqdev;
+
+ rcu_read_lock();
+
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
+ if (i == *pos)
+ return bpqdev;
+ }
+ return NULL;
+}
+
+static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct list_head *p;
+ struct bpqdev *bpqdev = v;
+
+ ++*pos;
+
+ if (v == SEQ_START_TOKEN)
+ p = rcu_dereference(list_next_rcu(&bpq_devices));
+ else
+ p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
+
+ return (p == &bpq_devices) ? NULL
+ : list_entry(p, struct bpqdev, bpq_list);
+}
+
+static void bpq_seq_stop(struct seq_file *seq, void *v)
+ __releases(RCU)
+{
+ rcu_read_unlock();
+}
+
+
+static int bpq_seq_show(struct seq_file *seq, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_puts(seq,
+ "dev ether destination accept from\n");
+ else {
+ const struct bpqdev *bpqdev = v;
+
+ seq_printf(seq, "%-5s %-10s %pM ",
+ bpqdev->axdev->name, bpqdev->ethdev->name,
+ bpqdev->dest_addr);
+
+ if (is_multicast_ether_addr(bpqdev->acpt_addr))
+ seq_printf(seq, "*\n");
+ else
+ seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
+
+ }
+ return 0;
+}
+
+static const struct seq_operations bpq_seqops = {
+ .start = bpq_seq_start,
+ .next = bpq_seq_next,
+ .stop = bpq_seq_stop,
+ .show = bpq_seq_show,
+};
+
+static int bpq_info_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &bpq_seqops);
+}
+
+static const struct file_operations bpq_info_fops = {
+ .owner = THIS_MODULE,
+ .open = bpq_info_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+
+/* ------------------------------------------------------------------------ */
+
+static const struct net_device_ops bpq_netdev_ops = {
+ .ndo_open = bpq_open,
+ .ndo_stop = bpq_close,
+ .ndo_start_xmit = bpq_xmit,
+ .ndo_set_mac_address = bpq_set_mac_address,
+ .ndo_do_ioctl = bpq_ioctl,
+};
+
+static void bpq_setup(struct net_device *dev)
+{
+ dev->netdev_ops = &bpq_netdev_ops;
+ dev->destructor = free_netdev;
+
+ memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
+ memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
+
+ dev->flags = 0;
+
+#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
+ dev->header_ops = &ax25_header_ops;
+#endif
+
+ dev->type = ARPHRD_AX25;
+ dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
+ dev->mtu = AX25_DEF_PACLEN;
+ dev->addr_len = AX25_ADDR_LEN;
+
+}
+
+/*
+ * Setup a new device.
+ */
+static int bpq_new_device(struct net_device *edev)
+{
+ int err;
+ struct net_device *ndev;
+ struct bpqdev *bpq;
+
+ ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
+ bpq_setup);
+ if (!ndev)
+ return -ENOMEM;
+
+
+ bpq = netdev_priv(ndev);
+ dev_hold(edev);
+ bpq->ethdev = edev;
+ bpq->axdev = ndev;
+
+ memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
+ memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
+
+ err = register_netdevice(ndev);
+ if (err)
+ goto error;
+ bpq_set_lockdep_class(ndev);
+
+ /* List protected by RTNL */
+ list_add_rcu(&bpq->bpq_list, &bpq_devices);
+ return 0;
+
+ error:
+ dev_put(edev);
+ free_netdev(ndev);
+ return err;
+
+}
+
+static void bpq_free_device(struct net_device *ndev)
+{
+ struct bpqdev *bpq = netdev_priv(ndev);
+
+ dev_put(bpq->ethdev);
+ list_del_rcu(&bpq->bpq_list);
+
+ unregister_netdevice(ndev);
+}
+
+/*
+ * Handle device status changes.
+ */
+static int bpq_device_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+ if (!net_eq(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 BPQ interface */
+ if (bpq_get_ax25_dev(dev) == NULL)
+ bpq_new_device(dev);
+ break;
+
+ case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
+ if ((dev = bpq_get_ax25_dev(dev)) != NULL)
+ dev_close(dev);
+ break;
+
+ case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
+ if ((dev = bpq_get_ax25_dev(dev)) != NULL)
+ bpq_free_device(dev);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+
+/* ------------------------------------------------------------------------ */
+
+/*
+ * Initialize driver. To be called from af_ax25 if not compiled as a
+ * module
+ */
+static int __init bpq_init_driver(void)
+{
+#ifdef CONFIG_PROC_FS
+ if (!proc_create("bpqether", S_IRUGO, init_net.proc_net,
+ &bpq_info_fops)) {
+ printk(KERN_ERR
+ "bpq: cannot create /proc/net/bpqether entry.\n");
+ return -ENOENT;
+ }
+#endif /* CONFIG_PROC_FS */
+
+ dev_add_pack(&bpq_packet_type);
+
+ register_netdevice_notifier(&bpq_dev_notifier);
+
+ printk(banner);
+
+ return 0;
+}
+
+static void __exit bpq_cleanup_driver(void)
+{
+ struct bpqdev *bpq;
+
+ dev_remove_pack(&bpq_packet_type);
+
+ unregister_netdevice_notifier(&bpq_dev_notifier);
+
+ remove_proc_entry("bpqether", init_net.proc_net);
+
+ rtnl_lock();
+ while (!list_empty(&bpq_devices)) {
+ bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
+ bpq_free_device(bpq->axdev);
+ }
+ rtnl_unlock();
+}
+
+MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
+MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
+MODULE_LICENSE("GPL");
+module_init(bpq_init_driver);
+module_exit(bpq_cleanup_driver);
Code Review / kvmfornfv.git / blobdiff