// SPDX-License-Identifier: GPL-2.0-only

  /* 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 <linux/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 = 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
  ",
  		    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 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, 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 = 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
  ");
  	return sprintf(page,"persistent, %sconnected
  ",
  	    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 sock *s;
  
          head = &vcc_hash[vci & (VCC_HTABLE_SIZE -1)];

  	sk_for_each(s, 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) {

  		result = -EUNATCH;

  		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 const 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 const 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) {
  		atm_dev_put(dev);
  		return 0;
  	}

  	dev_data->persist = 0;

  	if (PRIV(dev)->vcc) {
  		atm_dev_put(dev);
  		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);