root/trunk/batman-adv-kernelland/device.c @ 1543

/*
 * Copyright (C) 2007-2009 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

#include <linux/device.h>
#include "main.h"
#include "device.h"
#include "send.h"
#include "types.h"
#include "hash.h"
#include "hard-interface.h"

#include "compat.h"

static struct class *batman_class;

static int Major;       /* Major number assigned to our device driver */

static const struct file_operations fops = {
        .open = bat_device_open,
        .release = bat_device_release,
        .read = bat_device_read,
        .write = bat_device_write,
        .poll = bat_device_poll,
};

static struct device_client *device_client_hash[256];

void bat_device_init(void)
{
        int i;

        for (i = 0; i < 256; i++)
                device_client_hash[i] = NULL;
}

int bat_device_setup(void)
{
        int tmp_major;

        if (Major)
                return 1;

        /* register our device - kernel assigns a free major number */
        tmp_major = register_chrdev(0, DRIVER_DEVICE, &fops);
        if (tmp_major < 0) {
                printk(KERN_ERR "batman-adv:Registering the character device failed with %d\n",
                          tmp_major);
                return 0;
        }

        batman_class = class_create(THIS_MODULE, "batman-adv");

        if (IS_ERR(batman_class)) {
                printk(KERN_ERR "batman-adv:Could not register class 'batman-adv' \n");
                return 0;
        }

        device_create(batman_class, NULL, MKDEV(tmp_major, 0), NULL,
                      "batman-adv");

        Major = tmp_major;
        return 1;
}

void bat_device_destroy(void)
{
        if (!Major)
                return;

        device_destroy(batman_class, MKDEV(Major, 0));
        class_destroy(batman_class);

        /* Unregister the device */
        unregister_chrdev(Major, DRIVER_DEVICE);

        Major = 0;
}

int bat_device_open(struct inode *inode, struct file *file)
{
        unsigned int i;
        struct device_client *device_client;

        device_client = kmalloc(sizeof(struct device_client), GFP_KERNEL);

        if (!device_client)
                return -ENOMEM;

        for (i = 0; i < 256; i++) {
                if (!device_client_hash[i]) {
                        device_client_hash[i] = device_client;
                        break;
                }
        }

        if (device_client_hash[i] != device_client) {
                printk(KERN_ERR "batman-adv:Error - can't add another packet client: maximum number of clients reached \n");
                kfree(device_client);
                return -EXFULL;
        }

        INIT_LIST_HEAD(&device_client->queue_list);
        device_client->queue_len = 0;
        device_client->index = i;
        device_client->lock = __SPIN_LOCK_UNLOCKED(device_client->lock);
        init_waitqueue_head(&device_client->queue_wait);

        file->private_data = device_client;

        inc_module_count();
        return 0;
}

int bat_device_release(struct inode *inode, struct file *file)
{
        struct device_client *device_client =
                (struct device_client *)file->private_data;
        struct device_packet *device_packet;
        struct list_head *list_pos, *list_pos_tmp;
        unsigned long flags;

        spin_lock_irqsave(&device_client->lock, flags);

        /* for all packets in the queue ... */
        list_for_each_safe(list_pos, list_pos_tmp, &device_client->queue_list) {
                device_packet = list_entry(list_pos,
                                           struct device_packet, list);

                list_del(list_pos);
                kfree(device_packet);
        }

        device_client_hash[device_client->index] = NULL;
        spin_unlock_irqrestore(&device_client->lock, flags);

        kfree(device_client);
        dec_module_count();

        return 0;
}

ssize_t bat_device_read(struct file *file, char __user *buf, size_t count,
                        loff_t *ppos)
{
        struct device_client *device_client =
                (struct device_client *)file->private_data;
        struct device_packet *device_packet;
        int error;
        unsigned long flags;

        if ((file->f_flags & O_NONBLOCK) && (device_client->queue_len == 0))
                return -EAGAIN;

        if ((!buf) || (count < sizeof(struct icmp_packet)))
                return -EINVAL;

        if (!access_ok(VERIFY_WRITE, buf, count))
                return -EFAULT;

        error = wait_event_interruptible(device_client->queue_wait,
                                         device_client->queue_len);

        if (error)
                return error;

        spin_lock_irqsave(&device_client->lock, flags);

        device_packet = list_first_entry(&device_client->queue_list,
                                         struct device_packet, list);
        list_del(&device_packet->list);
        device_client->queue_len--;

        spin_unlock_irqrestore(&device_client->lock, flags);

        error = __copy_to_user(buf, &device_packet->icmp_packet,
                               sizeof(struct icmp_packet));

        kfree(device_packet);

        if (error)
                return error;

        return sizeof(struct icmp_packet);
}

ssize_t bat_device_write(struct file *file, const char __user *buff,
                         size_t len, loff_t *off)
{
        struct device_client *device_client =
                (struct device_client *)file->private_data;
        struct icmp_packet icmp_packet;
        struct orig_node *orig_node;
        struct batman_if *batman_if;
        uint8_t dstaddr[ETH_ALEN];
        unsigned long flags;

        if (len < sizeof(struct icmp_packet)) {
                bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: invalid packet size\n");
                return -EINVAL;
        }

        if (!access_ok(VERIFY_READ, buff, sizeof(struct icmp_packet)))
                return -EFAULT;

        if (__copy_from_user(&icmp_packet, buff, sizeof(icmp_packet)))
                return -EFAULT;

        if (icmp_packet.packet_type != BAT_ICMP) {
                bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
                return -EINVAL;
        }

        if (icmp_packet.msg_type != ECHO_REQUEST) {
                bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus message type (expected: ECHO_REQUEST)\n");
                return -EINVAL;
        }

        icmp_packet.uid = device_client->index;

        if (icmp_packet.version != COMPAT_VERSION) {
                icmp_packet.msg_type = PARAMETER_PROBLEM;
                icmp_packet.ttl = COMPAT_VERSION;
                bat_device_add_packet(device_client, &icmp_packet);
                goto out;
        }

        if (atomic_read(&module_state) != MODULE_ACTIVE)
                goto dst_unreach;

        spin_lock_irqsave(&orig_hash_lock, flags);
        orig_node = ((struct orig_node *)hash_find(orig_hash, icmp_packet.dst));

        if (!orig_node)
                goto unlock;

        if (!orig_node->router)
                goto unlock;

        batman_if = orig_node->batman_if;
        memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);

        spin_unlock_irqrestore(&orig_hash_lock, flags);

        if (!batman_if)
                goto dst_unreach;

        if (batman_if->if_active != IF_ACTIVE)
                goto dst_unreach;

        memcpy(icmp_packet.orig,
               batman_if->net_dev->dev_addr,
               ETH_ALEN);

        send_raw_packet((unsigned char *)&icmp_packet,
                        sizeof(struct icmp_packet),
                        batman_if, dstaddr);

        goto out;

unlock:
        spin_unlock_irqrestore(&orig_hash_lock, flags);
dst_unreach:
        icmp_packet.msg_type = DESTINATION_UNREACHABLE;
        bat_device_add_packet(device_client, &icmp_packet);
out:
        return len;
}

unsigned int bat_device_poll(struct file *file, poll_table *wait)
{
        struct device_client *device_client =
                (struct device_client *)file->private_data;

        poll_wait(file, &device_client->queue_wait, wait);

        if (device_client->queue_len > 0)
                return POLLIN | POLLRDNORM;

        return 0;
}

void bat_device_add_packet(struct device_client *device_client,
                           struct icmp_packet *icmp_packet)
{
        struct device_packet *device_packet;
        unsigned long flags;

        device_packet = kmalloc(sizeof(struct device_packet), GFP_KERNEL);

        if (!device_packet)
                return;

        INIT_LIST_HEAD(&device_packet->list);
        memcpy(&device_packet->icmp_packet, icmp_packet,
               sizeof(struct icmp_packet));

        spin_lock_irqsave(&device_client->lock, flags);

        /* while waiting for the lock the device_client could have been
         * deleted */
        if (!device_client_hash[icmp_packet->uid]) {
                spin_unlock_irqrestore(&device_client->lock, flags);
                kfree(device_packet);
                return;
        }

        list_add_tail(&device_packet->list, &device_client->queue_list);
        device_client->queue_len++;

        if (device_client->queue_len > 100) {
                device_packet = list_first_entry(&device_client->queue_list,
                                                 struct device_packet, list);

                list_del(&device_packet->list);
                kfree(device_packet);
                device_client->queue_len--;
        }

        spin_unlock_irqrestore(&device_client->lock, flags);

        wake_up(&device_client->queue_wait);
}

void bat_device_receive_packet(struct icmp_packet *icmp_packet)
{
        struct device_client *hash = device_client_hash[icmp_packet->uid];

        if (hash)
                bat_device_add_packet(hash, icmp_packet);
}