/*
* 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;
/*
* 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",
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);