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/*
* 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 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("bpqe
|