/*
|
* 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 <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) {
|
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))
|
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);
|
