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atmtcp.c

/* 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);

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