network.c

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/*
 * IPWireless 3G PCMCIA Network Driver
 *
 * Original code
 *   by Stephen Blackheath <[email protected]>,
 *      Ben Martel <[email protected]>
 *
 * Copyrighted as follows:
 *   Copyright (C) 2004 by Symmetric Systems Ltd (NZ)
 *
 * Various driver changes and rewrites, port to new kernels
 *   Copyright (C) 2006-2007 Jiri Kosina
 *
 * Misc code cleanups and updates
 *   Copyright (C) 2007 David Sterba
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/slab.h>
#include <linux/ppp-ioctl.h>
#include <linux/skbuff.h>

#include "network.h"
#include "hardware.h"
#include "main.h"
#include "tty.h"

#define MAX_ASSOCIATED_TTYS 2

#define SC_RCV_BITS     (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)

struct ipw_network {
    /* Hardware context, used for calls to hardware layer. */
    struct ipw_hardware *hardware;
    /* Context for kernel 'generic_ppp' functionality */
    struct ppp_channel *ppp_channel;
    /* tty context connected with IPW console */
    struct ipw_tty *associated_ttys[NO_OF_IPW_CHANNELS][MAX_ASSOCIATED_TTYS];
    /* True if ppp needs waking up once we're ready to xmit */
    int ppp_blocked;
    /* Number of packets queued up in hardware module. */
    int outgoing_packets_queued;
    /* Spinlock to avoid interrupts during shutdown */
    spinlock_t lock;
    struct mutex close_lock;

    /* PPP ioctl data, not actually used anywere */
    unsigned int flags;
    unsigned int rbits;
    u32 xaccm[8];
    u32 raccm;
    int mru;

    int shutting_down;
    unsigned int ras_control_lines;

    struct work_struct work_go_online;
    struct work_struct work_go_offline;
};

static void notify_packet_sent(void *callback_data, unsigned int packet_length)
{
    struct ipw_network *network = callback_data;
    unsigned long flags;

    spin_lock_irqsave(&network->lock, flags);
    network->outgoing_packets_queued--;
    if (network->ppp_channel != NULL) {
        if (network->ppp_blocked) {
            network->ppp_blocked = 0;
            spin_unlock_irqrestore(&network->lock, flags);
            ppp_output_wakeup(network->ppp_channel);
            if (ipwireless_debug)
                printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME
                       ": ppp unblocked\n");
        } else
            spin_unlock_irqrestore(&network->lock, flags);
    } else
        spin_unlock_irqrestore(&network->lock, flags);
}

/*
 * Called by the ppp system when it has a packet to send to the hardware.
 */
static int ipwireless_ppp_start_xmit(struct ppp_channel *ppp_channel,
                     struct sk_buff *skb)
{
    struct ipw_network *network = ppp_channel->private;
    unsigned long flags;

    spin_lock_irqsave(&network->lock, flags);
    if (network->outgoing_packets_queued < ipwireless_out_queue) {
        unsigned char *buf;
        static unsigned char header[] = {
            PPP_ALLSTATIONS, /* 0xff */
            PPP_UI,      /* 0x03 */
        };
        int ret;

        network->outgoing_packets_queued++;
        spin_unlock_irqrestore(&network->lock, flags);

        /*
         * If we have the requested amount of headroom in the skb we
         * were handed, then we can add the header efficiently.
         */
        if (skb_headroom(skb) >= 2) {
            memcpy(skb_push(skb, 2), header, 2);
            ret = ipwireless_send_packet(network->hardware,
                           IPW_CHANNEL_RAS, skb->data,
                           skb->len,
                           notify_packet_sent,
                           network);
            if (ret == -1) {
                skb_pull(skb, 2);
                return 0;
            }
        } else {
            /* Otherwise (rarely) we do it inefficiently. */
            buf = kmalloc(skb->len + 2, GFP_ATOMIC);
            if (!buf)
                return 0;
            memcpy(buf + 2, skb->data, skb->len);
            memcpy(buf, header, 2);
            ret = ipwireless_send_packet(network->hardware,
                           IPW_CHANNEL_RAS, buf,
                           skb->len + 2,
                           notify_packet_sent,
                           network);
            kfree(buf);
            if (ret == -1)
                return 0;
        }
        kfree_skb(skb);
        return 1;
    } else {
        /*
         * Otherwise reject the packet, and flag that the ppp system
         * needs to be unblocked once we are ready to send.
         */
        network->ppp_blocked = 1;
        spin_unlock_irqrestore(&network->lock, flags);
        if (ipwireless_debug)
            printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": ppp blocked\n");
        return 0;
    }
}

/* Handle an ioctl call that has come in via ppp. (copy of ppp_async_ioctl() */
static int ipwireless_ppp_ioctl(struct ppp_channel *ppp_channel,
                unsigned int cmd, unsigned long arg)
{
    struct ipw_network *network = ppp_channel->private;
    int err, val;
    u32 accm[8];
    int __user *user_arg = (int __user *) arg;

    err = -EFAULT;
    switch (cmd) {
    case PPPIOCGFLAGS:
        val = network->flags | network->rbits;
        if (put_user(val, user_arg))
            break;
        err = 0;
        break;

    case PPPIOCSFLAGS:
        if (get_user(val, user_arg))
            break;
        network->flags = val & ~SC_RCV_BITS;
        network->rbits = val & SC_RCV_BITS;
        err = 0;
        break;

    case PPPIOCGASYNCMAP:
        if (put_user(network->xaccm[0], user_arg))
            break;
        err = 0;
        break;

    case PPPIOCSASYNCMAP:
        if (get_user(network->xaccm[0], user_arg))
            break;
        err = 0;
        break;

    case PPPIOCGRASYNCMAP:
        if (put_user(network->raccm, user_arg))
            break;
        err = 0;
        break;

    case PPPIOCSRASYNCMAP:
        if (get_user(network->raccm, user_arg))
            break;
        err = 0;
        break;

    case PPPIOCGXASYNCMAP:
        if (copy_to_user((void __user *) arg, network->xaccm,
                    sizeof(network->xaccm)))
            break;
        err = 0;
        break;

    case PPPIOCSXASYNCMAP:
        if (copy_from_user(accm, (void __user *) arg, sizeof(accm)))
            break;
        accm[2] &= ~0x40000000U;    /* can't escape 0x5e */
        accm[3] |= 0x60000000U; /* must escape 0x7d, 0x7e */
        memcpy(network->xaccm, accm, sizeof(network->xaccm));
        err = 0;
        break;

    case PPPIOCGMRU:
        if (put_user(network->mru, user_arg))
            break;
        err = 0;
        break;

    case PPPIOCSMRU:
        if (get_user(val, user_arg))
            break;
        if (val < PPP_MRU)
            val = PPP_MRU;
        network->mru = val;
        err = 0;
        break;

    default:
        err = -ENOTTY;
    }

    return err;
}

static const struct ppp_channel_ops ipwireless_ppp_channel_ops = {
    .start_xmit = ipwireless_ppp_start_xmit,
    .ioctl      = ipwireless_ppp_ioctl
};

static void do_go_online(struct work_struct *work_go_online)
{
    struct ipw_network *network =
        container_of(work_go_online, struct ipw_network,
                work_go_online);
    unsigned long flags;

    spin_lock_irqsave(&network->lock, flags);
    if (!network->ppp_channel) {
        struct ppp_channel *channel;

        spin_unlock_irqrestore(&network->lock, flags);
        channel = kzalloc(sizeof(struct ppp_channel), GFP_KERNEL);
        if (!channel) {
            printk(KERN_ERR IPWIRELESS_PCCARD_NAME
                    ": unable to allocate PPP channel\n");
            return;
        }
        channel->private = network;
        channel->mtu = 16384;   /* Wild guess */
        channel->hdrlen = 2;
        channel->ops = &ipwireless_ppp_channel_ops;

        network->flags = 0;
        network->rbits = 0;
        network->mru = PPP_MRU;
        memset(network->xaccm, 0, sizeof(network->xaccm));
        network->xaccm[0] = ~0U;
        network->xaccm[3] = 0x60000000U;
        network->raccm = ~0U;
        if (ppp_register_channel(channel) < 0) {
            printk(KERN_ERR IPWIRELESS_PCCARD_NAME
                    ": unable to register PPP channel\n");
            kfree(channel);
            return;
        }
        spin_lock_irqsave(&network->lock, flags);
        network->ppp_channel = channel;
    }
    spin_unlock_irqrestore(&network->lock, flags);
}

static void do_go_offline(struct work_struct *work_go_offline)
{
    struct ipw_network *network =
        container_of(work_go_offline, struct ipw_network,
                work_go_offline);
    unsigned long flags;

    mutex_lock(&network->close_lock);
    spin_lock_irqsave(&network->lock, flags);
    if (network->ppp_channel != NULL) {
        struct ppp_channel *channel = network->ppp_channel;

        network->ppp_channel = NULL;
        spin_unlock_irqrestore(&network->lock, flags);
        mutex_unlock(&network->close_lock);
        ppp_unregister_channel(channel);
    } else {
        spin_unlock_irqrestore(&network->lock, flags);
        mutex_unlock(&network->close_lock);
    }
}

void ipwireless_network_notify_control_line_change(struct ipw_network *network,
                           unsigned int channel_idx,
                           unsigned int control_lines,
                           unsigned int changed_mask)
{
    int i;

    if (channel_idx == IPW_CHANNEL_RAS)
        network->ras_control_lines = control_lines;

    for (i = 0; i < MAX_ASSOCIATED_TTYS; i++) {
        struct ipw_tty *tty =
            network->associated_ttys[channel_idx][i];

        /*
         * If it's associated with a tty (other than the RAS channel
         * when we're online), then send the data to that tty.  The RAS
         * channel's data is handled above - it always goes through
         * ppp_generic.
         */
        if (tty)
            ipwireless_tty_notify_control_line_change(tty,
                                  channel_idx,
                                  control_lines,
                                  changed_mask);
    }
}

/*
 * Some versions of firmware stuff packets with 0xff 0x03 (PPP: ALLSTATIONS, UI)
 * bytes, which are required on sent packet, but not always present on received
 * packets
 */
static struct sk_buff *ipw_packet_received_skb(unsigned char *data,
                           unsigned int length)
{
    struct sk_buff *skb;

    if (length > 2 && data[0] == PPP_ALLSTATIONS && data[1] == PPP_UI) {
        length -= 2;
        data += 2;
    }

    skb = dev_alloc_skb(length + 4);
    skb_reserve(skb, 2);
    memcpy(skb_put(skb, length), data, length);

    return skb;
}

void ipwireless_network_packet_received(struct ipw_network *network,
                    unsigned int channel_idx,
                    unsigned char *data,
                    unsigned int length)
{
    int i;
    unsigned long flags;

    for (i = 0; i < MAX_ASSOCIATED_TTYS; i++) {
        struct ipw_tty *tty = network->associated_ttys[channel_idx][i];

        if (!tty)
            continue;

        /*
         * If it's associated with a tty (other than the RAS channel
         * when we're online), then send the data to that tty.  The RAS
         * channel's data is handled above - it always goes through
         * ppp_generic.
         */
        if (channel_idx == IPW_CHANNEL_RAS
                && (network->ras_control_lines &
                    IPW_CONTROL_LINE_DCD) != 0
                && ipwireless_tty_is_modem(tty)) {
            /*
             * If data came in on the RAS channel and this tty is
             * the modem tty, and we are online, then we send it to
             * the PPP layer.
             */
            mutex_lock(&network->close_lock);
            spin_lock_irqsave(&network->lock, flags);
            if (network->ppp_channel != NULL) {
                struct sk_buff *skb;

                spin_unlock_irqrestore(&network->lock,
                        flags);

                /* Send the data to the ppp_generic module. */
                skb = ipw_packet_received_skb(data, length);
                ppp_input(network->ppp_channel, skb);
            } else
                spin_unlock_irqrestore(&network->lock,
                        flags);
            mutex_unlock(&network->close_lock);
        }
        /* Otherwise we send it out the tty. */
        else
            ipwireless_tty_received(tty, data, length);
    }
}

struct ipw_network *ipwireless_network_create(struct ipw_hardware *hw)
{
    struct ipw_network *network =
        kzalloc(sizeof(struct ipw_network), GFP_ATOMIC);

    if (!network)
        return NULL;

    spin_lock_init(&network->lock);
    mutex_init(&network->close_lock);

    network->hardware = hw;

    INIT_WORK(&network->work_go_online, do_go_online);
    INIT_WORK(&network->work_go_offline, do_go_offline);

    ipwireless_associate_network(hw, network);

    return network;
}

void ipwireless_network_free(struct ipw_network *network)
{
    network->shutting_down = 1;

    ipwireless_ppp_close(network);
    flush_work(&network->work_go_online);
    flush_work(&network->work_go_offline);

    ipwireless_stop_interrupts(network->hardware);
    ipwireless_associate_network(network->hardware, NULL);

    kfree(network);
}

void ipwireless_associate_network_tty(struct ipw_network *network,
                      unsigned int channel_idx,
                      struct ipw_tty *tty)
{
    int i;

    for (i = 0; i < MAX_ASSOCIATED_TTYS; i++)
        if (network->associated_ttys[channel_idx][i] == NULL) {
            network->associated_ttys[channel_idx][i] = tty;
            break;
        }
}

void ipwireless_disassociate_network_ttys(struct ipw_network *network,
                      unsigned int channel_idx)
{
    int i;

    for (i = 0; i < MAX_ASSOCIATED_TTYS; i++)
        network->associated_ttys[channel_idx][i] = NULL;
}

void ipwireless_ppp_open(struct ipw_network *network)
{
    if (ipwireless_debug)
        printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": online\n");
    schedule_work(&network->work_go_online);
}

void ipwireless_ppp_close(struct ipw_network *network)
{
    /* Disconnect from the wireless network. */
    if (ipwireless_debug)
        printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME ": offline\n");
    schedule_work(&network->work_go_offline);
}

int ipwireless_ppp_channel_index(struct ipw_network *network)
{
    int ret = -1;
    unsigned long flags;

    spin_lock_irqsave(&network->lock, flags);
    if (network->ppp_channel != NULL)
        ret = ppp_channel_index(network->ppp_channel);
    spin_unlock_irqrestore(&network->lock, flags);

    return ret;
}

int ipwireless_ppp_unit_number(struct ipw_network *network)
{
    int ret = -1;
    unsigned long flags;

    spin_lock_irqsave(&network->lock, flags);
    if (network->ppp_channel != NULL)
        ret = ppp_unit_number(network->ppp_channel);
    spin_unlock_irqrestore(&network->lock, flags);

    return ret;
}

int ipwireless_ppp_mru(const struct ipw_network *network)
{
    return network->mru;
}