atmtcp.c

Go to the documentation of this file.

/* drivers/atm/atmtcp.c - ATM over TCP "device" driver */

/* Written 1997-2000 by Werner Almesberger, EPFL LRC/ICA */


#include <linux/module.h>
#include <linux/wait.h>
#include <linux/atmdev.h>
#include <linux/atm_tcp.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/atomic.h>


extern int atm_init_aal5(struct atm_vcc *vcc); /* "raw" AAL5 transport */


#define PRIV(dev) ((struct atmtcp_dev_data *) ((dev)->dev_data))


struct atmtcp_dev_data {
    struct atm_vcc *vcc;    /* control VCC; NULL if detached */
    int persist;        /* non-zero if persistent */
};


#define DEV_LABEL    "atmtcp"

#define MAX_VPI_BITS  8 /* simplifies life */
#define MAX_VCI_BITS 16


/*
 * Hairy code ahead: the control VCC may be closed while we're still
 * waiting for an answer, so we need to re-validate out_vcc every once
 * in a while.
 */


static int atmtcp_send_control(struct atm_vcc *vcc,int type,
    const struct atmtcp_control *msg,int flag)
{
    DECLARE_WAITQUEUE(wait,current);
    struct atm_vcc *out_vcc;
    struct sk_buff *skb;
    struct atmtcp_control *new_msg;
    int old_test;
    int error = 0;

    out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
    if (!out_vcc) return -EUNATCH;
    skb = alloc_skb(sizeof(*msg),GFP_KERNEL);
    if (!skb) return -ENOMEM;
    mb();
    out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
    if (!out_vcc) {
        dev_kfree_skb(skb);
        return -EUNATCH;
    }
    atm_force_charge(out_vcc,skb->truesize);
    new_msg = (struct atmtcp_control *) skb_put(skb,sizeof(*new_msg));
    *new_msg = *msg;
    new_msg->hdr.length = ATMTCP_HDR_MAGIC;
    new_msg->type = type;
    memset(&new_msg->vcc,0,sizeof(atm_kptr_t));
    *(struct atm_vcc **) &new_msg->vcc = vcc;
    old_test = test_bit(flag,&vcc->flags);
    out_vcc->push(out_vcc,skb);
    add_wait_queue(sk_sleep(sk_atm(vcc)), &wait);
    while (test_bit(flag,&vcc->flags) == old_test) {
        mb();
        out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
        if (!out_vcc) {
            error = -EUNATCH;
            break;
        }
        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule();
    }
    set_current_state(TASK_RUNNING);
    remove_wait_queue(sk_sleep(sk_atm(vcc)), &wait);
    return error;
}


static int atmtcp_recv_control(const struct atmtcp_control *msg)
{
    struct atm_vcc *vcc = *(struct atm_vcc **) &msg->vcc;

    vcc->vpi = msg->addr.sap_addr.vpi;
    vcc->vci = msg->addr.sap_addr.vci;
    vcc->qos = msg->qos;
    sk_atm(vcc)->sk_err = -msg->result;
    switch (msg->type) {
        case ATMTCP_CTRL_OPEN:
        change_bit(ATM_VF_READY,&vcc->flags);
        break;
        case ATMTCP_CTRL_CLOSE:
        change_bit(ATM_VF_ADDR,&vcc->flags);
        break;
        default:
        printk(KERN_ERR "atmtcp_recv_control: unknown type %d\n",
            msg->type);
        return -EINVAL;
    }
    wake_up(sk_sleep(sk_atm(vcc)));
    return 0;
}


static void atmtcp_v_dev_close(struct atm_dev *dev)
{
    /* Nothing.... Isn't this simple :-)  -- REW */
}


static int atmtcp_v_open(struct atm_vcc *vcc)
{
    struct atmtcp_control msg;
    int error;
    short vpi = vcc->vpi;
    int vci = vcc->vci;

    memset(&msg,0,sizeof(msg));
    msg.addr.sap_family = AF_ATMPVC;
    msg.hdr.vpi = htons(vpi);
    msg.addr.sap_addr.vpi = vpi;
    msg.hdr.vci = htons(vci);
    msg.addr.sap_addr.vci = vci;
    if (vpi == ATM_VPI_UNSPEC || vci == ATM_VCI_UNSPEC) return 0;
    msg.type = ATMTCP_CTRL_OPEN;
    msg.qos = vcc->qos;
    set_bit(ATM_VF_ADDR,&vcc->flags);
    clear_bit(ATM_VF_READY,&vcc->flags); /* just in case ... */
    error = atmtcp_send_control(vcc,ATMTCP_CTRL_OPEN,&msg,ATM_VF_READY);
    if (error) return error;
    return -sk_atm(vcc)->sk_err;
}


static void atmtcp_v_close(struct atm_vcc *vcc)
{
    struct atmtcp_control msg;

    memset(&msg,0,sizeof(msg));
    msg.addr.sap_family = AF_ATMPVC;
    msg.addr.sap_addr.vpi = vcc->vpi;
    msg.addr.sap_addr.vci = vcc->vci;
    clear_bit(ATM_VF_READY,&vcc->flags);
    (void) atmtcp_send_control(vcc,ATMTCP_CTRL_CLOSE,&msg,ATM_VF_ADDR);
}


static int atmtcp_v_ioctl(struct atm_dev *dev,unsigned int cmd,void __user *arg)
{
    struct atm_cirange ci;
    struct atm_vcc *vcc;
    struct hlist_node *node;
    struct sock *s;
    int i;

    if (cmd != ATM_SETCIRANGE) return -ENOIOCTLCMD;
    if (copy_from_user(&ci, arg,sizeof(ci))) return -EFAULT;
    if (ci.vpi_bits == ATM_CI_MAX) ci.vpi_bits = MAX_VPI_BITS;
    if (ci.vci_bits == ATM_CI_MAX) ci.vci_bits = MAX_VCI_BITS;
    if (ci.vpi_bits > MAX_VPI_BITS || ci.vpi_bits < 0 ||
        ci.vci_bits > MAX_VCI_BITS || ci.vci_bits < 0) return -EINVAL;
    read_lock(&vcc_sklist_lock);
    for(i = 0; i < VCC_HTABLE_SIZE; ++i) {
        struct hlist_head *head = &vcc_hash[i];

        sk_for_each(s, node, head) {
            vcc = atm_sk(s);
            if (vcc->dev != dev)
                continue;
            if ((vcc->vpi >> ci.vpi_bits) ||
                (vcc->vci >> ci.vci_bits)) {
                read_unlock(&vcc_sklist_lock);
                return -EBUSY;
            }
        }
    }
    read_unlock(&vcc_sklist_lock);
    dev->ci_range = ci;
    return 0;
}


static int atmtcp_v_send(struct atm_vcc *vcc,struct sk_buff *skb)
{
    struct atmtcp_dev_data *dev_data;
    struct atm_vcc *out_vcc=NULL; /* Initializer quietens GCC warning */
    struct sk_buff *new_skb;
    struct atmtcp_hdr *hdr;
    int size;

    if (vcc->qos.txtp.traffic_class == ATM_NONE) {
        if (vcc->pop) vcc->pop(vcc,skb);
        else dev_kfree_skb(skb);
        return -EINVAL;
    }
    dev_data = PRIV(vcc->dev);
    if (dev_data) out_vcc = dev_data->vcc;
    if (!dev_data || !out_vcc) {
        if (vcc->pop) vcc->pop(vcc,skb);
        else dev_kfree_skb(skb);
        if (dev_data) return 0;
        atomic_inc(&vcc->stats->tx_err);
        return -ENOLINK;
    }
    size = skb->len+sizeof(struct atmtcp_hdr);
    new_skb = atm_alloc_charge(out_vcc,size,GFP_ATOMIC);
    if (!new_skb) {
        if (vcc->pop) vcc->pop(vcc,skb);
        else dev_kfree_skb(skb);
        atomic_inc(&vcc->stats->tx_err);
        return -ENOBUFS;
    }
    hdr = (void *) skb_put(new_skb,sizeof(struct atmtcp_hdr));
    hdr->vpi = htons(vcc->vpi);
    hdr->vci = htons(vcc->vci);
    hdr->length = htonl(skb->len);
    skb_copy_from_linear_data(skb, skb_put(new_skb, skb->len), skb->len);
    if (vcc->pop) vcc->pop(vcc,skb);
    else dev_kfree_skb(skb);
    out_vcc->push(out_vcc,new_skb);
    atomic_inc(&vcc->stats->tx);
    atomic_inc(&out_vcc->stats->rx);
    return 0;
}


static int atmtcp_v_proc(struct atm_dev *dev,loff_t *pos,char *page)
{
    struct atmtcp_dev_data *dev_data = PRIV(dev);

    if (*pos) return 0;
    if (!dev_data->persist) return sprintf(page,"ephemeral\n");
    return sprintf(page,"persistent, %sconnected\n",
        dev_data->vcc ? "" : "dis");
}


static void atmtcp_c_close(struct atm_vcc *vcc)
{
    struct atm_dev *atmtcp_dev;
    struct atmtcp_dev_data *dev_data;

    atmtcp_dev = (struct atm_dev *) vcc->dev_data;
    dev_data = PRIV(atmtcp_dev);
    dev_data->vcc = NULL;
    if (dev_data->persist) return;
    atmtcp_dev->dev_data = NULL;
    kfree(dev_data);
    atm_dev_deregister(atmtcp_dev);
    vcc->dev_data = NULL;
    module_put(THIS_MODULE);
}


static struct atm_vcc *find_vcc(struct atm_dev *dev, short vpi, int vci)
{
        struct hlist_head *head;
        struct atm_vcc *vcc;
        struct hlist_node *node;
        struct sock *s;

        head = &vcc_hash[vci & (VCC_HTABLE_SIZE -1)];

        sk_for_each(s, node, head) {
                vcc = atm_sk(s);
                if (vcc->dev == dev &&
                    vcc->vci == vci && vcc->vpi == vpi &&
                    vcc->qos.rxtp.traffic_class != ATM_NONE) {
                                return vcc;
                }
        }
        return NULL;
}


static int atmtcp_c_send(struct atm_vcc *vcc,struct sk_buff *skb)
{
    struct atm_dev *dev;
    struct atmtcp_hdr *hdr;
    struct atm_vcc *out_vcc;
    struct sk_buff *new_skb;
    int result = 0;

    if (!skb->len) return 0;
    dev = vcc->dev_data;
    hdr = (struct atmtcp_hdr *) skb->data;
    if (hdr->length == ATMTCP_HDR_MAGIC) {
        result = atmtcp_recv_control(
            (struct atmtcp_control *) skb->data);
        goto done;
    }
    read_lock(&vcc_sklist_lock);
    out_vcc = find_vcc(dev, ntohs(hdr->vpi), ntohs(hdr->vci));
    read_unlock(&vcc_sklist_lock);
    if (!out_vcc) {
        atomic_inc(&vcc->stats->tx_err);
        goto done;
    }
    skb_pull(skb,sizeof(struct atmtcp_hdr));
    new_skb = atm_alloc_charge(out_vcc,skb->len,GFP_KERNEL);
    if (!new_skb) {
        result = -ENOBUFS;
        goto done;
    }
    __net_timestamp(new_skb);
    skb_copy_from_linear_data(skb, skb_put(new_skb, skb->len), skb->len);
    out_vcc->push(out_vcc,new_skb);
    atomic_inc(&vcc->stats->tx);
    atomic_inc(&out_vcc->stats->rx);
done:
    if (vcc->pop) vcc->pop(vcc,skb);
    else dev_kfree_skb(skb);
    return result;
}


/*
 * Device operations for the virtual ATM devices created by ATMTCP.
 */


static struct atmdev_ops atmtcp_v_dev_ops = {
    .dev_close  = atmtcp_v_dev_close,
    .open       = atmtcp_v_open,
    .close      = atmtcp_v_close,
    .ioctl      = atmtcp_v_ioctl,
    .send       = atmtcp_v_send,
    .proc_read  = atmtcp_v_proc,
    .owner      = THIS_MODULE
};


/*
 * Device operations for the ATMTCP control device.
 */


static struct atmdev_ops atmtcp_c_dev_ops = {
    .close      = atmtcp_c_close,
    .send       = atmtcp_c_send
};


static struct atm_dev atmtcp_control_dev = {
    .ops        = &atmtcp_c_dev_ops,
    .type       = "atmtcp",
    .number     = 999,
    .lock       = __SPIN_LOCK_UNLOCKED(atmtcp_control_dev.lock)
};


static int atmtcp_create(int itf,int persist,struct atm_dev **result)
{
    struct atmtcp_dev_data *dev_data;
    struct atm_dev *dev;

    dev_data = kmalloc(sizeof(*dev_data),GFP_KERNEL);
    if (!dev_data)
        return -ENOMEM;

    dev = atm_dev_register(DEV_LABEL,NULL,&atmtcp_v_dev_ops,itf,NULL);
    if (!dev) {
        kfree(dev_data);
        return itf == -1 ? -ENOMEM : -EBUSY;
    }
    dev->ci_range.vpi_bits = MAX_VPI_BITS;
    dev->ci_range.vci_bits = MAX_VCI_BITS;
    dev->dev_data = dev_data;
    PRIV(dev)->vcc = NULL;
    PRIV(dev)->persist = persist;
    if (result) *result = dev;
    return 0;
}


static int atmtcp_attach(struct atm_vcc *vcc,int itf)
{
    struct atm_dev *dev;

    dev = NULL;
    if (itf != -1) dev = atm_dev_lookup(itf);
    if (dev) {
        if (dev->ops != &atmtcp_v_dev_ops) {
            atm_dev_put(dev);
            return -EMEDIUMTYPE;
        }
        if (PRIV(dev)->vcc) {
            atm_dev_put(dev);
            return -EBUSY;
        }
    }
    else {
        int error;

        error = atmtcp_create(itf,0,&dev);
        if (error) return error;
    }
    PRIV(dev)->vcc = vcc;
    vcc->dev = &atmtcp_control_dev;
    vcc_insert_socket(sk_atm(vcc));
    set_bit(ATM_VF_META,&vcc->flags);
    set_bit(ATM_VF_READY,&vcc->flags);
    vcc->dev_data = dev;
    (void) atm_init_aal5(vcc); /* @@@ losing AAL in transit ... */
    vcc->stats = &atmtcp_control_dev.stats.aal5;
    return dev->number;
}


static int atmtcp_create_persistent(int itf)
{
    return atmtcp_create(itf,1,NULL);
}


static int atmtcp_remove_persistent(int itf)
{
    struct atm_dev *dev;
    struct atmtcp_dev_data *dev_data;

    dev = atm_dev_lookup(itf);
    if (!dev) return -ENODEV;
    if (dev->ops != &atmtcp_v_dev_ops) {
        atm_dev_put(dev);
        return -EMEDIUMTYPE;
    }
    dev_data = PRIV(dev);
    if (!dev_data->persist) return 0;
    dev_data->persist = 0;
    if (PRIV(dev)->vcc) return 0;
    kfree(dev_data);
    atm_dev_put(dev);
    atm_dev_deregister(dev);
    return 0;
}

static int atmtcp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
    int err = 0;
    struct atm_vcc *vcc = ATM_SD(sock);

    if (cmd != SIOCSIFATMTCP && cmd != ATMTCP_CREATE && cmd != ATMTCP_REMOVE)
        return -ENOIOCTLCMD;

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

    switch (cmd) {
        case SIOCSIFATMTCP:
            err = atmtcp_attach(vcc, (int) arg);
            if (err >= 0) {
                sock->state = SS_CONNECTED;
                __module_get(THIS_MODULE);
            }
            break;
        case ATMTCP_CREATE:
            err = atmtcp_create_persistent((int) arg);
            break;
        case ATMTCP_REMOVE:
            err = atmtcp_remove_persistent((int) arg);
            break;
    }
    return err;
}

static struct atm_ioctl atmtcp_ioctl_ops = {
    .owner  = THIS_MODULE,
    .ioctl  = atmtcp_ioctl,
};

static __init int atmtcp_init(void)
{
    register_atm_ioctl(&atmtcp_ioctl_ops);
    return 0;
}


static void __exit atmtcp_exit(void)
{
    deregister_atm_ioctl(&atmtcp_ioctl_ops);
}

MODULE_LICENSE("GPL");
module_init(atmtcp_init);
module_exit(atmtcp_exit);