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/* 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 <asm/uaccess.h>

#include <asm/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_atm(vcc)->sk_sleep, &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_atm(vcc)->sk_sleep, &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_atm(vcc)->sk_sleep);

        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,&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) 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);