/*****************************************************************************
* wanmain.c     WAN Multiprotocol Router Module. Main code.
*
*               This module is completely hardware-independent and provides
*               the following common services for the WAN Link Drivers:
*                o WAN device management (registering, unregistering)
*                o Network interface management
*                o Physical connection management (dial-up, incoming calls)
*                o Logical connection management (switched virtual circuits)
*                o Protocol encapsulation/decapsulation
*
* Author:       Gideon Hack
*
* Copyright:    (c) 1995-1999 Sangoma Technologies Inc.
*
*               This program 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.
* ============================================================================
* Nov 24, 2000  Nenad Corbic    Updated for 2.4.X kernels
* Nov 07, 2000  Nenad Corbic    Fixed the Mulit-Port PPP for kernels 2.2.16 and
*                               greater.
* Aug 2,  2000  Nenad Corbic    Block the Multi-Port PPP from running on
*                               kernels 2.2.16 or greater.  The SyncPPP
*                               has changed.
* Jul 13, 2000  Nenad Corbic    Added SyncPPP support
*                               Added extra debugging in device_setup().
* Oct 01, 1999  Gideon Hack     Update for s514 PCI card
* Dec 27, 1996  Gene Kozin      Initial version (based on Sangoma's WANPIPE)
* Jan 16, 1997  Gene Kozin      router_devlist made public
* Jan 31, 1997  Alan Cox        Hacked it about a bit for 2.1
* Jun 27, 1997  Alan Cox        realigned with vendor code
* Oct 15, 1997  Farhan Thawar   changed wan_encapsulate to add a pad byte of 0
* Apr 20, 1998  Alan Cox        Fixed 2.1 symbols
* May 17, 1998  K. Baranowski   Fixed SNAP encapsulation in wan_encapsulate
* Dec 15, 1998  Arnaldo Melo    support for firmwares of up to 128000 bytes
*                               check wandev->setup return value
* Dec 22, 1998  Arnaldo Melo    vmalloc/vfree used in device_setup to allocate
*                               kernel memory and copy configuration data to
*                               kernel space (for big firmwares)
* Jun 02, 1999  Gideon Hack     Updates for Linux 2.0.X and 2.2.X kernels.
*****************************************************************************/

#include <linux/stddef.h>       /* offsetof(), etc. */
#include <linux/capability.h>
#include <linux/errno.h>        /* return codes */
#include <linux/kernel.h>
#include <linux/module.h>       /* support for loadable modules */
#include <linux/slab.h>         /* kmalloc(), kfree() */
#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/string.h>       /* inline mem*, str* functions */

#include <asm/byteorder.h>      /* htons(), etc. */
#include <linux/wanrouter.h>    /* WAN router API definitions */

#include <linux/vmalloc.h>      /* vmalloc, vfree */
#include <asm/uaccess.h>        /* copy_to/from_user */
#include <linux/init.h>         /* __initfunc et al. */

#define KMEM_SAFETYZONE 8

#define DEV_TO_SLAVE(dev)       (*((struct net_device **)netdev_priv(dev)))

/*
 *      Function Prototypes
 */

/*
 *      WAN device IOCTL handlers
 */

static DEFINE_MUTEX(wanrouter_mutex);
static int wanrouter_device_setup(struct wan_device *wandev,
                                  wandev_conf_t __user *u_conf);
static int wanrouter_device_stat(struct wan_device *wandev,
                                 wandev_stat_t __user *u_stat);
static int wanrouter_device_shutdown(struct wan_device *wandev);
static int wanrouter_device_new_if(struct wan_device *wandev,
                                   wanif_conf_t __user *u_conf);
static int wanrouter_device_del_if(struct wan_device *wandev,
                                   char __user *u_name);

/*
 *      Miscellaneous
 */

static struct wan_device *wanrouter_find_device(char *name);
static int wanrouter_delete_interface(struct wan_device *wandev, char *name);
static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
        __acquires(lock);
static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
        __releases(lock);



/*
 *      Global Data
 */

static char wanrouter_fullname[]  = "Sangoma WANPIPE Router";
static char wanrouter_copyright[] = "(c) 1995-2000 Sangoma Technologies Inc.";
static char wanrouter_modname[] = ROUTER_NAME; /* short module name */
struct wan_device* wanrouter_router_devlist; /* list of registered devices */

/*
 *      Organize Unique Identifiers for encapsulation/decapsulation
 */

#if 0
static unsigned char wanrouter_oui_ether[] = { 0x00, 0x00, 0x00 };
static unsigned char wanrouter_oui_802_2[] = { 0x00, 0x80, 0xC2 };
#endif

static int __init wanrouter_init(void)
{
        int err;

        printk(KERN_INFO "%s v%u.%u %s\n",
               wanrouter_fullname, ROUTER_VERSION, ROUTER_RELEASE,
               wanrouter_copyright);

        err = wanrouter_proc_init();
        if (err)
                printk(KERN_INFO "%s: can't create entry in proc filesystem!\n",
                       wanrouter_modname);

        return err;
}

static void __exit wanrouter_cleanup (void)
{
        wanrouter_proc_cleanup();
}

/*
 * This is just plain dumb.  We should move the bugger to drivers/net/wan,
 * slap it first in directory and make it module_init().  The only reason
 * for subsys_initcall() here is that net goes after drivers (why, BTW?)
 */
subsys_initcall(wanrouter_init);
module_exit(wanrouter_cleanup);

/*
 *      Kernel APIs
 */

/*
 *      Register WAN device.
 *      o verify device credentials
 *      o create an entry for the device in the /proc/net/router directory
 *      o initialize internally maintained fields of the wan_device structure
 *      o link device data space to a singly-linked list
 *      o if it's the first device, then start kernel 'thread'
 *      o increment module use count
 *
 *      Return:
 *      0       Ok
 *      < 0     error.
 *
 *      Context:        process
 */


int register_wan_device(struct wan_device *wandev)
{
        int err, namelen;

        if ((wandev == NULL) || (wandev->magic != ROUTER_MAGIC) ||
            (wandev->name == NULL))
                return -EINVAL;

        namelen = strlen(wandev->name);
        if (!namelen || (namelen > WAN_DRVNAME_SZ))
                return -EINVAL;

        if (wanrouter_find_device(wandev->name))
                return -EEXIST;

#ifdef WANDEBUG
        printk(KERN_INFO "%s: registering WAN device %s\n",
               wanrouter_modname, wandev->name);
#endif

        /*
         *      Register /proc directory entry
         */
        err = wanrouter_proc_add(wandev);
        if (err) {
                printk(KERN_INFO
                        "%s: can't create /proc/net/router/%s entry!\n",
                        wanrouter_modname, wandev->name);
                return err;
        }

        /*
         *      Initialize fields of the wan_device structure maintained by the
         *      router and update local data.
         */

        wandev->ndev = 0;
        wandev->dev  = NULL;
        wandev->next = wanrouter_router_devlist;
        wanrouter_router_devlist = wandev;
        return 0;
}

/*
 *      Unregister WAN device.
 *      o shut down device
 *      o unlink device data space from the linked list
 *      o delete device entry in the /proc/net/router directory
 *      o decrement module use count
 *
 *      Return:         0       Ok
 *                      <0      error.
 *      Context:        process
 */


int unregister_wan_device(char *name)
{
        struct wan_device *wandev, *prev;

        if (name == NULL)
                return -EINVAL;

        for (wandev = wanrouter_router_devlist, prev = NULL;
                wandev && strcmp(wandev->name, name);
                prev = wandev, wandev = wandev->next)
                ;
        if (wandev == NULL)
                return -ENODEV;

#ifdef WANDEBUG
        printk(KERN_INFO "%s: unregistering WAN device %s\n",
               wanrouter_modname, name);
#endif

        if (wandev->state != WAN_UNCONFIGURED)
                wanrouter_device_shutdown(wandev);

        if (prev)
                prev->next = wandev->next;
        else
                wanrouter_router_devlist = wandev->next;

        wanrouter_proc_delete(wandev);
        return 0;
}

#if 0

/*
 *      Encapsulate packet.
 *
 *      Return: encapsulation header size
 *              < 0     - unsupported Ethertype
 *
 *      Notes:
 *      1. This function may be called on interrupt context.
 */


int wanrouter_encapsulate(struct sk_buff *skb, struct net_device *dev,
                          unsigned short type)
{
        int hdr_len = 0;

        switch (type) {
        case ETH_P_IP:          /* IP datagram encapsulation */
                hdr_len += 1;
                skb_push(skb, 1);
                skb->data[0] = NLPID_IP;
                break;

        case ETH_P_IPX:         /* SNAP encapsulation */
        case ETH_P_ARP:
                hdr_len += 7;
                skb_push(skb, 7);
                skb->data[0] = 0;
                skb->data[1] = NLPID_SNAP;
                skb_copy_to_linear_data_offset(skb, 2, wanrouter_oui_ether,
                                               sizeof(wanrouter_oui_ether));
                *((unsigned short*)&skb->data[5]) = htons(type);
                break;

        default:                /* Unknown packet type */
                printk(KERN_INFO
                        "%s: unsupported Ethertype 0x%04X on interface %s!\n",
                        wanrouter_modname, type, dev->name);
                hdr_len = -EINVAL;
        }
        return hdr_len;
}


/*
 *      Decapsulate packet.
 *
 *      Return: Ethertype (in network order)
 *                      0       unknown encapsulation
 *
 *      Notes:
 *      1. This function may be called on interrupt context.
 */


__be16 wanrouter_type_trans(struct sk_buff *skb, struct net_device *dev)
{
        int cnt = skb->data[0] ? 0 : 1; /* there may be a pad present */
        __be16 ethertype;

        switch (skb->data[cnt]) {
        case NLPID_IP:          /* IP datagramm */
                ethertype = htons(ETH_P_IP);
                cnt += 1;
                break;

        case NLPID_SNAP:        /* SNAP encapsulation */
                if (memcmp(&skb->data[cnt + 1], wanrouter_oui_ether,
                           sizeof(wanrouter_oui_ether))){
                        printk(KERN_INFO
                                "%s: unsupported SNAP OUI %02X-%02X-%02X "
                                "on interface %s!\n", wanrouter_modname,
                                skb->data[cnt+1], skb->data[cnt+2],
                                skb->data[cnt+3], dev->name);
                        return 0;
                }
                ethertype = *((__be16*)&skb->data[cnt+4]);
                cnt += 6;
                break;

        /* add other protocols, e.g. CLNP, ESIS, ISIS, if needed */

        default:
                printk(KERN_INFO
                        "%s: unsupported NLPID 0x%02X on interface %s!\n",
                        wanrouter_modname, skb->data[cnt], dev->name);
                return 0;
        }
        skb->protocol = ethertype;
        skb->pkt_type = PACKET_HOST;    /*      Physically point to point */
        skb_pull(skb, cnt);
        skb_reset_mac_header(skb);
        return ethertype;
}

#endif  /*  0  */

/*
 *      WAN device IOCTL.
 *      o find WAN device associated with this node
 *      o execute requested action or pass command to the device driver
 */

long wanrouter_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct inode *inode = file->f_path.dentry->d_inode;
        int err = 0;
        struct proc_dir_entry *dent;
        struct wan_device *wandev;
        void __user *data = (void __user *)arg;

        if (!capable(CAP_NET_ADMIN))
                return -EPERM;

        if ((cmd >> 8) != ROUTER_IOCTL)
                return -EINVAL;

        dent = PDE(inode);
        if ((dent == NULL) || (dent->data == NULL))
                return -EINVAL;

        wandev = dent->data;
        if (wandev->magic != ROUTER_MAGIC)
                return -EINVAL;

        mutex_lock(&wanrouter_mutex);
        switch (cmd) {
        case ROUTER_SETUP:
                err = wanrouter_device_setup(wandev, data);
                break;

        case ROUTER_DOWN:
                err = wanrouter_device_shutdown(wandev);
                break;

        case ROUTER_STAT:
                err = wanrouter_device_stat(wandev, data);
                break;

        case ROUTER_IFNEW:
                err = wanrouter_device_new_if(wandev, data);
                break;

        case ROUTER_IFDEL:
                err = wanrouter_device_del_if(wandev, data);
                break;

        case ROUTER_IFSTAT:
                break;

        default:
                if ((cmd >= ROUTER_USER) &&
                    (cmd <= ROUTER_USER_MAX) &&
                    wandev->ioctl)
                        err = wandev->ioctl(wandev, cmd, arg);
                else err = -EINVAL;
        }
        mutex_unlock(&wanrouter_mutex);
        return err;
}

/*
 *      WAN Driver IOCTL Handlers
 */

/*
 *      Setup WAN link device.
 *      o verify user address space
 *      o allocate kernel memory and copy configuration data to kernel space
 *      o if configuration data includes extension, copy it to kernel space too
 *      o call driver's setup() entry point
 */

static int wanrouter_device_setup(struct wan_device *wandev,
                                  wandev_conf_t __user *u_conf)
{
        void *data = NULL;
        wandev_conf_t *conf;
        int err = -EINVAL;

        if (wandev->setup == NULL) {    /* Nothing to do ? */
                printk(KERN_INFO "%s: ERROR, No setup script: wandev->setup()\n",
                                wandev->name);
                return 0;
        }

        conf = kmalloc(sizeof(wandev_conf_t), GFP_KERNEL);
        if (conf == NULL){
                printk(KERN_INFO "%s: ERROR, Failed to allocate kernel memory !\n",
                                wandev->name);
                return -ENOBUFS;
        }

        if (copy_from_user(conf, u_conf, sizeof(wandev_conf_t))) {
                printk(KERN_INFO "%s: Failed to copy user config data to kernel space!\n",
                                wandev->name);
                kfree(conf);
                return -EFAULT;
        }

        if (conf->magic != ROUTER_MAGIC) {
                kfree(conf);
                printk(KERN_INFO "%s: ERROR, Invalid MAGIC Number\n",
                                wandev->name);
                return -EINVAL;
        }

        if (conf->data_size && conf->data) {
                if (conf->data_size > 128000) {
                        printk(KERN_INFO
                            "%s: ERROR, Invalid firmware data size %i !\n",
                                        wandev->name, conf->data_size);
                        kfree(conf);
                        return -EINVAL;
                }

                data = vmalloc(conf->data_size);
                if (!data) {
                        printk(KERN_INFO
                                "%s: ERROR, Failed allocate kernel memory !\n",
                                wandev->name);
                        kfree(conf);
                        return -ENOBUFS;
                }
                if (!copy_from_user(data, conf->data, conf->data_size)) {
                        conf->data = data;
                        err = wandev->setup(wandev, conf);
                } else {
                        printk(KERN_INFO
                             "%s: ERROR, Failed to copy from user data !\n",
                               wandev->name);
                        err = -EFAULT;
                }
                vfree(data);
        } else {
                printk(KERN_INFO
                    "%s: ERROR, No firmware found ! Firmware size = %i !\n",
                                wandev->name, conf->data_size);
        }

        kfree(conf);
        return err;
}

/*
 *      Shutdown WAN device.
 *      o delete all not opened logical channels for this device
 *      o call driver's shutdown() entry point
 */

static int wanrouter_device_shutdown(struct wan_device *wandev)
{
        struct net_device *dev;
        int err=0;

        if (wandev->state == WAN_UNCONFIGURED)
                return 0;

        printk(KERN_INFO "\n%s: Shutting Down!\n",wandev->name);

        for (dev = wandev->dev; dev;) {
                err = wanrouter_delete_interface(wandev, dev->name);
                if (err)
                        return err;
                /* The above function deallocates the current dev
                 * structure. Therefore, we cannot use netdev_priv(dev)
                 * as the next element: wandev->dev points to the
                 * next element */
                dev = wandev->dev;
        }

        if (wandev->ndev)
                return -EBUSY;  /* there are opened interfaces  */

        if (wandev->shutdown)
                err=wandev->shutdown(wandev);

        return err;
}

/*
 *      Get WAN device status & statistics.
 */

static int wanrouter_device_stat(struct wan_device *wandev,
                                 wandev_stat_t __user *u_stat)
{
        wandev_stat_t stat;

        memset(&stat, 0, sizeof(stat));

        /* Ask device driver to update device statistics */
        if ((wandev->state != WAN_UNCONFIGURED) && wandev->update)
                wandev->update(wandev);

        /* Fill out structure */
        stat.ndev  = wandev->ndev;
        stat.state = wandev->state;

        if (copy_to_user(u_stat, &stat, sizeof(stat)))
                return -EFAULT;

        return 0;
}

/*
 *      Create new WAN interface.
 *      o verify user address space
 *      o copy configuration data to kernel address space
 *      o allocate network interface data space
 *      o call driver's new_if() entry point
 *      o make sure there is no interface name conflict
 *      o register network interface
 */

static int wanrouter_device_new_if(struct wan_device *wandev,
                                   wanif_conf_t __user *u_conf)
{
        wanif_conf_t *cnf;
        struct net_device *dev = NULL;
        int err;

        if ((wandev->state == WAN_UNCONFIGURED) || (wandev->new_if == NULL))
                return -ENODEV;

        cnf = kmalloc(sizeof(wanif_conf_t), GFP_KERNEL);
        if (!cnf)
                return -ENOBUFS;

        err = -EFAULT;
        if (copy_from_user(cnf, u_conf, sizeof(wanif_conf_t)))
                goto out;

        err = -EINVAL;
        if (cnf->magic != ROUTER_MAGIC)
                goto out;

        if (cnf->config_id == WANCONFIG_MPPP) {
                printk(KERN_INFO "%s: Wanpipe Mulit-Port PPP support has not been compiled in!\n",
                                wandev->name);
                err = -EPROTONOSUPPORT;
                goto out;
        } else {
                err = wandev->new_if(wandev, dev, cnf);
        }

        if (!err) {
                /* Register network interface. This will invoke init()
                 * function supplied by the driver.  If device registered
                 * successfully, add it to the interface list.
                 */

                if (dev->name == NULL) {
                        err = -EINVAL;
                } else {

                        #ifdef WANDEBUG
                        printk(KERN_INFO "%s: registering interface %s...\n",
                                wanrouter_modname, dev->name);
                        #endif

                        err = register_netdev(dev);
                        if (!err) {
                                struct net_device *slave = NULL;
                                unsigned long smp_flags=0;

                                lock_adapter_irq(&wandev->lock, &smp_flags);

                                if (wandev->dev == NULL) {
                                        wandev->dev = dev;
                                } else {
                                        for (slave=wandev->dev;
                                             DEV_TO_SLAVE(slave);
                                             slave = DEV_TO_SLAVE(slave))
                                                DEV_TO_SLAVE(slave) = dev;
                                }
                                ++wandev->ndev;

                                unlock_adapter_irq(&wandev->lock, &smp_flags);
                                err = 0;        /* done !!! */
                                goto out;
                        }
                }
                if (wandev->del_if)
                        wandev->del_if(wandev, dev);
                free_netdev(dev);
        }

out:
        kfree(cnf);
        return err;
}


/*
 *      Delete WAN logical channel.
 *       o verify user address space
 *       o copy configuration data to kernel address space
 */

static int wanrouter_device_del_if(struct wan_device *wandev, char __user *u_name)
{
        char name[WAN_IFNAME_SZ + 1];
        int err = 0;

        if (wandev->state == WAN_UNCONFIGURED)
                return -ENODEV;

        memset(name, 0, sizeof(name));

        if (copy_from_user(name, u_name, WAN_IFNAME_SZ))
                return -EFAULT;

        err = wanrouter_delete_interface(wandev, name);
        if (err)
                return err;

        /* If last interface being deleted, shutdown card
         * This helps with administration at leaf nodes
         * (You can tell if the person at the other end of the phone
         * has an interface configured) and avoids DoS vulnerabilities
         * in binary driver files - this fixes a problem with the current
         * Sangoma driver going into strange states when all the network
         * interfaces are deleted and the link irrecoverably disconnected.
         */

        if (!wandev->ndev && wandev->shutdown)
                err = wandev->shutdown(wandev);

        return err;
}

/*
 *      Miscellaneous Functions
 */

/*
 *      Find WAN device by name.
 *      Return pointer to the WAN device data space or NULL if device not found.
 */

static struct wan_device *wanrouter_find_device(char *name)
{
        struct wan_device *wandev;

        for (wandev = wanrouter_router_devlist;
             wandev && strcmp(wandev->name, name);
                wandev = wandev->next);
        return wandev;
}

/*
 *      Delete WAN logical channel identified by its name.
 *      o find logical channel by its name
 *      o call driver's del_if() entry point
 *      o unregister network interface
 *      o unlink channel data space from linked list of channels
 *      o release channel data space
 *
 *      Return: 0               success
 *              -ENODEV         channel not found.
 *              -EBUSY          interface is open
 *
 *      Note: If (force != 0), then device will be destroyed even if interface
 *      associated with it is open. It's caller's responsibility to make
 *      sure that opened interfaces are not removed!
 */

static int wanrouter_delete_interface(struct wan_device *wandev, char *name)
{
        struct net_device *dev = NULL, *prev = NULL;
        unsigned long smp_flags=0;

        lock_adapter_irq(&wandev->lock, &smp_flags);
        dev = wandev->dev;
        prev = NULL;
        while (dev && strcmp(name, dev->name)) {
                struct net_device **slave = netdev_priv(dev);
                prev = dev;
                dev = *slave;
        }
        unlock_adapter_irq(&wandev->lock, &smp_flags);

        if (dev == NULL)
                return -ENODEV; /* interface not found */

        if (netif_running(dev))
                return -EBUSY;  /* interface in use */

        if (wandev->del_if)
                wandev->del_if(wandev, dev);

        lock_adapter_irq(&wandev->lock, &smp_flags);
        if (prev) {
                struct net_device **prev_slave = netdev_priv(prev);
                struct net_device **slave = netdev_priv(dev);

                *prev_slave = *slave;
        } else {
                struct net_device **slave = netdev_priv(dev);
                wandev->dev = *slave;
        }
        --wandev->ndev;
        unlock_adapter_irq(&wandev->lock, &smp_flags);

        printk(KERN_INFO "%s: unregistering '%s'\n", wandev->name, dev->name);

        unregister_netdev(dev);

        free_netdev(dev);

        return 0;
}

static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
        __acquires(lock)
{
        spin_lock_irqsave(lock, *smp_flags);
}


static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
        __releases(lock)
{
        spin_unlock_irqrestore(lock, *smp_flags);
}

EXPORT_SYMBOL(register_wan_device);
EXPORT_SYMBOL(unregister_wan_device);

MODULE_LICENSE("GPL");

/*
 *      End
 */