diff options
Diffstat (limited to 'drivers/net/hamradio/bpqether.c')
| -rw-r--r-- | drivers/net/hamradio/bpqether.c | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c new file mode 100644 index 000000000..5c17c92ad --- /dev/null +++ b/drivers/net/hamradio/bpqether.c @@ -0,0 +1,609 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * G8BPQ compatible "AX.25 via ethernet" driver release 004 + * + * This code REQUIRES 2.0.0 or higher/ NET3.029 + * + * 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 <linux/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/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 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, + lockdep_rtnl_is_held()) { + 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 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->needs_free_netdev = true; + + memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); + memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); + + dev->flags = 0; + dev->features = NETIF_F_LLTX; /* Allow recursion */ + +#if IS_ENABLED(CONFIG_AX25) + 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; + + eth_broadcast_addr(bpq->dest_addr); + eth_broadcast_addr(bpq->acpt_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) && !bpq_get_ax25_dev(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_seq("bpqether", 0444, init_net.proc_net, &bpq_seqops)) { + 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); |