Import 2.3.10pre5

[davej-history.git] / drivers / net / hamradio / bpqether.c

/*
 *      G8BPQ compatible "AX.25 via ethernet" driver release 003
 *
 *      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/config.h>
#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 <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/firewall.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>

#include <net/ip.h>
#include <net/arp.h>

#include <linux/bpqether.h>

static unsigned char ax25_bcast[AX25_ADDR_LEN] =
        {'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
static unsigned char ax25_defaddr[AX25_ADDR_LEN] =
        {'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};

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 device *, struct packet_type *);
static int bpq_device_event(struct notifier_block *, unsigned long, void *);
static char *bpq_print_ethaddr(unsigned char *);

static struct packet_type bpq_packet_type = {
        0,              /* ntohs(ETH_P_BPQ),*/
        0,              /* copy */
        bpq_rcv,
        NULL,
        NULL,
};

static struct notifier_block bpq_dev_notifier = {
        bpq_device_event,
        0
};


#define MAXBPQDEV 100

static struct bpqdev {
        struct bpqdev *next;
        char   ethname[14];             /* ether device name */
        struct device *ethdev;          /* link to ethernet device */
        struct device axdev;            /* bpq device (bpq#) */
        struct net_device_stats stats;  /* some statistics */
        char   dest_addr[6];            /* ether destination address */
        char   acpt_addr[6];            /* accept ether frames from this address only */
} *bpq_devices = NULL;


/* ------------------------------------------------------------------------ */


/*
 *      Get the ethernet device for a BPQ device
 */
static __inline__ struct device *bpq_get_ether_dev(struct device *dev)
{
        struct bpqdev *bpq;

        bpq = (struct bpqdev *)dev->priv;

        return (bpq != NULL) ? bpq->ethdev : NULL;
}

/*
 *      Get the BPQ device for the ethernet device
 */
static __inline__ struct device *bpq_get_ax25_dev(struct device *dev)
{
        struct bpqdev *bpq;

        for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next)
                if (bpq->ethdev == dev)
                        return &bpq->axdev;

        return NULL;
}

static __inline__ int dev_is_ethdev(struct device *dev)
{
        return (
                        dev->type == ARPHRD_ETHER
                        && strncmp(dev->name, "dummy", 5)
        );
}

/*
 *      Sanity check: remove all devices that ceased to exists and
 *      return '1' if the given BPQ device was affected.
 */
static int bpq_check_devices(struct device *dev)
{
        struct bpqdev *bpq, *bpq_prev;
        int result = 0;
        unsigned long flags;

        save_flags(flags);
        cli();

        bpq_prev = NULL;

        for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next) {
                if (!dev_get(bpq->ethname)) {
                        if (bpq_prev)
                                bpq_prev->next = bpq->next;
                        else
                                bpq_devices = bpq->next;

                        if (&bpq->axdev == dev)
                                result = 1;

                        /* We should be locked, call 
                         * unregister_netdevice directly 
                         */

                        unregister_netdevice(&bpq->axdev);
                        kfree(bpq);
                }

                bpq_prev = bpq;
        }

        restore_flags(flags);

        return result;
}


/* ------------------------------------------------------------------------ */


/*
 *      Receive an AX.25 frame via an ethernet interface.
 */
static int bpq_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *ptype)
{
        int len;
        char * ptr;
        struct ethhdr *eth = (struct ethhdr *)skb->mac.raw;
        struct bpqdev *bpq;

        skb->sk = NULL;         /* Initially we don't know who it's for */

        dev = bpq_get_ax25_dev(dev);

        if (dev == NULL || dev->start == 0) {
                kfree_skb(skb);
                return 0;
        }

        /*
         * if we want to accept frames from just one ethernet device
         * we check the source address of the sender.
         */

        bpq = (struct bpqdev *)dev->priv;

        if (!(bpq->acpt_addr[0] & 0x01) && memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN)) {
                printk(KERN_DEBUG "bpqether: wrong dest %s\n", bpq_print_ethaddr(eth->h_source));
                kfree_skb(skb);
                return 0;
        }

        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 */

        ((struct bpqdev *)dev->priv)->stats.rx_packets++;
        ((struct bpqdev *)dev->priv)->stats.rx_bytes+=len;

        ptr = skb_push(skb, 1);
        *ptr = 0;

        skb->dev = dev;
        skb->protocol = htons(ETH_P_AX25);
        skb->mac.raw = skb->data;
        skb->pkt_type = PACKET_HOST;

        netif_rx(skb);

        return 0;
}

/*
 *      Send an AX.25 frame via an ethernet interface
 */
static int bpq_xmit(struct sk_buff *skb, struct device *dev)
{
        struct sk_buff *newskb;
        unsigned char *ptr;
        struct bpqdev *bpq;
        int size;

        /*
         * Just to be *really* sure not to send anything if the interface
         * is down, the ethernet device may have gone.
         */
        if (!dev->start) {
                bpq_check_devices(dev);
                kfree_skb(skb);
                return -ENODEV;
        }

        skb_pull(skb, 1);
        size = skb->len;

        /*
         * The AX.25 code leaves enough room for the ethernet header, but
         * sendto() does not.
         */
        if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
                if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
                        printk(KERN_WARNING "bpqether: out of memory\n");
                        kfree_skb(skb);
                        return -ENOMEM;
                }

                if (skb->sk != NULL)
                        skb_set_owner_w(newskb, skb->sk);

                kfree_skb(skb);
                skb = newskb;
        }

        skb->protocol = htons(ETH_P_AX25);

        ptr = skb_push(skb, 2);

        *ptr++ = (size + 5) % 256;
        *ptr++ = (size + 5) / 256;

        bpq = (struct bpqdev *)dev->priv;

        if ((dev = bpq_get_ether_dev(dev)) == NULL) {
                bpq->stats.tx_dropped++;
                kfree_skb(skb);
                return -ENODEV;
        }

        skb->dev = dev;
        skb->nh.raw = skb->data;
        dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
        bpq->stats.tx_packets++;
        bpq->stats.tx_bytes+=skb->len;
  
        dev_queue_xmit(skb);

        return 0;
}

/*
 *      Statistics
 */
static struct net_device_stats *bpq_get_stats(struct device *dev)
{
        struct bpqdev *bpq;

        bpq = (struct bpqdev *)dev->priv;

        return &bpq->stats;
}

/*
 *      Set AX.25 callsign
 */
static int bpq_set_mac_address(struct 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 device *dev, struct ifreq *ifr, int cmd)
{
        int err;
        struct bpq_ethaddr *ethaddr = (struct bpq_ethaddr *)ifr->ifr_data;
        struct bpqdev *bpq = dev->priv;
        struct bpq_req req;

        if (!suser())
                return -EPERM;

        if (bpq == NULL)                /* woops! */
                return -ENODEV;

        switch (cmd) {
                case SIOCSBPQETHOPT:
                        if ((err = verify_area(VERIFY_WRITE, ifr->ifr_data, sizeof(struct bpq_req))) != 0)
                                return err;
                        copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req));
                        switch (req.cmd) {
                                case SIOCGBPQETHPARAM:
                                case SIOCSBPQETHPARAM:
                                default:
                                        return -EINVAL;
                        }

                        break;

                case SIOCSBPQETHADDR:
                        if ((err = verify_area(VERIFY_READ, ethaddr, sizeof(struct bpq_ethaddr))) != 0)
                                return err;
                        copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN);
                        copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN);
                        break;

                default:
                        return -EINVAL;
        }

        return 0;
}

/*
 * open/close a device
 */
static int bpq_open(struct device *dev)
{
        if (bpq_check_devices(dev))
                return -ENODEV;         /* oops, it's gone */

        dev->tbusy = 0;
        dev->start = 1;

        MOD_INC_USE_COUNT;

        return 0;
}

static int bpq_close(struct device *dev)
{
        dev->tbusy = 1;
        dev->start = 0;

        MOD_DEC_USE_COUNT;

        return 0;
}

/*
 * currently unused
 */
static int bpq_dev_init(struct device *dev)
{
        return 0;
}


/* ------------------------------------------------------------------------ */


/*
 *      Proc filesystem
 */
static char * bpq_print_ethaddr(unsigned char *e)
{
        static char buf[18];

        sprintf(buf, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
                e[0], e[1], e[2], e[3], e[4], e[5]);

        return buf;
}

int bpq_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
{
        struct bpqdev *bpqdev;
        int len     = 0;
        off_t pos   = 0;
        off_t begin = 0;

        cli();

        len += sprintf(buffer, "dev   ether      destination        accept from\n");

        for (bpqdev = bpq_devices; bpqdev != NULL; bpqdev = bpqdev->next) {
                len += sprintf(buffer + len, "%-5s %-10s %s  ",
                        bpqdev->axdev.name, bpqdev->ethname,
                        bpq_print_ethaddr(bpqdev->dest_addr));

                len += sprintf(buffer + len, "%s\n",
                        (bpqdev->acpt_addr[0] & 0x01) ? "*" : bpq_print_ethaddr(bpqdev->acpt_addr));

                pos = begin + len;

                if (pos < offset) {
                        len   = 0;
                        begin = pos;
                }

                if (pos > offset + length)
                        break;
        }

        sti();

        *start = buffer + (offset - begin);
        len   -= (offset - begin);

        if (len > length) len = length;

        return len;
}


/* ------------------------------------------------------------------------ */


/*
 *      Setup a new device.
 */
static int bpq_new_device(struct device *dev)
{
        int k;
        unsigned char *buf;
        struct bpqdev *bpq, *bpq2;

        if ((bpq = kmalloc(sizeof(struct bpqdev), GFP_KERNEL)) == NULL)
                return -ENOMEM;

        memset(bpq, 0, sizeof(struct bpqdev));

        bpq->ethdev = dev;

        bpq->ethname[sizeof(bpq->ethname)-1] = '\0';
        strncpy(bpq->ethname, dev->name, sizeof(bpq->ethname)-1);

        memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
        memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));

        dev = &bpq->axdev;
        buf = kmalloc(14, GFP_KERNEL);

        for (k = 0; k < MAXBPQDEV; k++) {
                struct device *odev;

                sprintf(buf, "bpq%d", k);

                if ((odev = dev_get(buf)) == NULL || bpq_check_devices(odev))
                        break;
        }

        if (k == MAXBPQDEV) {
                kfree(bpq);
                return -ENODEV;
        }

        dev->priv = (void *)bpq;        /* pointer back */
        dev->name = buf;
        dev->init = bpq_dev_init;

        /* We should be locked, call register_netdevice() directly. */

        if (register_netdevice(dev) != 0) {
                kfree(bpq);
                return -EIO;
        }

        dev_init_buffers(dev);

        dev->hard_start_xmit = bpq_xmit;
        dev->open            = bpq_open;
        dev->stop            = bpq_close;
        dev->set_mac_address = bpq_set_mac_address;
        dev->get_stats       = bpq_get_stats;
        dev->do_ioctl        = bpq_ioctl;

        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->hard_header     = ax25_encapsulate;
        dev->rebuild_header  = ax25_rebuild_header;
#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;

        cli();

        if (bpq_devices == NULL) {
                bpq_devices = bpq;
        } else {
                for (bpq2 = bpq_devices; bpq2->next != NULL; bpq2 = bpq2->next);
                bpq2->next = bpq;
        }

        sti();

        return 0;
}


/*
 *      Handle device status changes.
 */
static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
{
        struct device *dev = (struct device *)ptr;

        if (!dev_is_ethdev(dev))
                return NOTIFY_DONE;

        bpq_check_devices(NULL);

        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;

                default:
                        break;
        }

        return NOTIFY_DONE;
}


/* ------------------------------------------------------------------------ */

/*
 * Initialize driver. To be called from af_ax25 if not compiled as a
 * module
 */
int __init bpq_init(void)
{
        struct device *dev;

        bpq_packet_type.type  = htons(ETH_P_BPQ);
        dev_add_pack(&bpq_packet_type);

        register_netdevice_notifier(&bpq_dev_notifier);

        printk(KERN_INFO "AX.25 ethernet driver version 0.01\n");

#ifdef CONFIG_PROC_FS
        proc_net_register(&(struct proc_dir_entry) {
                PROC_NET_AX25_BPQETHER, 8, "bpqether",
                S_IFREG | S_IRUGO, 1, 0, 0,
                0, &proc_net_inode_operations,
                bpq_get_info
        });
#endif

        read_lock_bh(&dev_base_lock);
        for (dev = dev_base; dev != NULL; dev = dev->next) {
                if (dev_is_ethdev(dev)) {
                        read_unlock_bh(&dev_base_lock);
                        bpq_new_device(dev);
                        read_lock_bh(&dev_base_lock);
                }
        }
        read_unlock_bh(&dev_base_lock);
out:
        return 0;
}

#ifdef MODULE
EXPORT_NO_SYMBOLS;

MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@lykos.oche.de>");
MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");

int init_module(void)
{
        return bpq_init();
}

void cleanup_module(void)
{
        struct bpqdev *bpq;

        dev_remove_pack(&bpq_packet_type);

        unregister_netdevice_notifier(&bpq_dev_notifier);

#ifdef CONFIG_PROC_FS
        proc_net_unregister(PROC_NET_AX25_BPQETHER);
#endif

        for (bpq = bpq_devices; bpq != NULL; bpq = bpq->next)
                unregister_netdev(&bpq->axdev);
}
#endif