/*
   Copyright (C) 2008 Free Software Foundation, Inc.
   Written by Zheng Da.

   This file is part of the GNU Hurd.

   The GNU Hurd is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   The GNU Hurd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */

/* This file implement the virtual network interface */

#include <string.h>
#include <stdio.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <error.h>

#include <pthread.h>

#include "vdev.h"
#include "queue.h"
#include "bpf_impl.h"
#include "util.h"

#define ETH_HLEN sizeof (struct ethhdr)

static struct vether_device *dev_head;
static int dev_num;

/* This lock is only used to protected the virtual device list.
 * TODO every device structure should has its own lock to protect itself. */
static pthread_mutex_t dev_list_lock = PTHREAD_MUTEX_INITIALIZER;

mach_msg_type_t header_type = 
{
  MACH_MSG_TYPE_BYTE,
  8,
  NET_HDW_HDR_MAX,
  TRUE,
  FALSE,
  FALSE,
  0
};

mach_msg_type_t packet_type = 
{
  MACH_MSG_TYPE_BYTE,	/* name */
  8,			/* size */
  0,			/* number */
  TRUE,			/* inline */
  FALSE,			/* longform */
  FALSE			/* deallocate */
};

int
get_dev_num ()
{
  return dev_num;
}

struct vether_device *
lookup_dev_by_name (char *name)
{
  struct vether_device *vdev;
  pthread_mutex_lock (&dev_list_lock);
  for (vdev = dev_head; vdev; vdev = vdev->next)
    {
      if (strncmp (vdev->name, name, IFNAMSIZ) == 0)
	break;
    }
  pthread_mutex_unlock (&dev_list_lock);
  return vdev;
}

int
foreach_dev_do (int (func) (struct vether_device *))
{
  struct vether_device *vdev;
  int rval = 0;
  pthread_mutex_lock (&dev_list_lock);
  for (vdev = dev_head; vdev; vdev = vdev->next)
    {
      pthread_mutex_unlock (&dev_list_lock);
      /* func() can stop the loop by returning <> 0 */
      rval = func (vdev);
      pthread_mutex_lock (&dev_list_lock);
      if (rval)
	break;
    }
  pthread_mutex_unlock (&dev_list_lock);
  return rval;
}

/* Remove all filters with the dead name. */
int 
remove_dead_port_from_dev (mach_port_t dead_port)
{
  struct vether_device *vdev;
  pthread_mutex_lock (&dev_list_lock);
  for (vdev = dev_head; vdev; vdev = vdev->next)
    {
      remove_dead_filter (&vdev->port_list,
			  &vdev->port_list.if_rcv_port_list, dead_port);
      remove_dead_filter (&vdev->port_list,
			  &vdev->port_list.if_snd_port_list, dead_port);
    }
  pthread_mutex_unlock (&dev_list_lock);
  return 0;
}

/* Add a new virtual interface to the multiplexer. */
struct vether_device *
add_vdev (char *name, int size, 
	  struct port_class *class, struct port_bucket *bucket)
{
  error_t err;
  struct vether_device *vdev;

  if (size < sizeof (*vdev))
    size = sizeof (*vdev);
  err = ports_create_port (class, bucket, size, &vdev);
  if (err)
    return NULL;

  vdev->dev_port = ports_get_right (vdev);
  ports_port_deref (vdev);
  strncpy (vdev->name, name, IFNAMSIZ);
  vdev->if_header_size = ETH_HLEN;
  vdev->if_mtu = ETH_MTU;
  vdev->if_header_format = HDR_ETHERNET;
  vdev->if_address_size = ETH_ALEN;
  vdev->if_flags = 0;
  vdev->if_address[0] = 0x52;
  vdev->if_address[1] = 0x54;
  *(int *)(vdev->if_address + 2) = random ();

  queue_init (&vdev->port_list.if_rcv_port_list);
  queue_init (&vdev->port_list.if_snd_port_list);

  pthread_mutex_lock (&dev_list_lock);
  vdev->next = dev_head;
  dev_head = vdev;
  vdev->pprev = &dev_head;
  if (vdev->next)
    vdev->next->pprev = &vdev->next;
  dev_num++;
  pthread_mutex_unlock (&dev_list_lock);

  debug ("initialize the virtual device\n");
  return vdev;
}

void
destroy_vdev (void *port)
{
  struct vether_device *vdev = (struct vether_device *)port;

  debug ("device %s is going to be destroyed\n", vdev->name);
  /* Delete it from the virtual device list */
  pthread_mutex_lock (&dev_list_lock);
  *vdev->pprev = vdev->next;
  if (vdev->next)
    vdev->next->pprev = vdev->pprev;
  dev_num--;
  pthread_mutex_unlock (&dev_list_lock);

  /* TODO Delete all filters in the interface,
   * there shouldn't be any filters left */
  destroy_filters (&vdev->port_list);
}

/* Test if there are devices existing in the list */
int
has_vdev ()
{
  return dev_head != NULL;
}

/* Broadcast the packet to all virtual interfaces
 * except the one the packet is from */
int 
broadcast_pack (char *data, int datalen, struct vether_device *from_vdev)
{
  int internal_deliver_pack (struct vether_device *vdev)
    {
      if (from_vdev == vdev)
	return 0;
      return deliver_pack (data, datalen, vdev);
    }

  return foreach_dev_do (internal_deliver_pack);
}

/* Create a message, and deliver it. */
int 
deliver_pack (char *data, int datalen, struct vether_device *vdev)
{
  struct net_rcv_msg msg;
  int pack_size;
  struct ethhdr *header;
  struct packet_header *packet;

  pack_size = datalen - sizeof (struct ethhdr);
  /* remember message sizes must be rounded up */
  msg.msg_hdr.msgh_size = (((mach_msg_size_t) (sizeof(struct net_rcv_msg)
					       - NET_RCV_MAX + pack_size)) + 3) & ~3;

  header = (struct ethhdr *) msg.header;
  packet = (struct packet_header *) msg.packet;
  msg.header_type = header_type;
  memcpy (header, data, sizeof (struct ethhdr));
  msg.packet_type = packet_type;
  memcpy (packet + 1, data + sizeof (struct ethhdr), pack_size);
  packet->type = header->h_proto;
  packet->length = pack_size + sizeof (struct packet_header);
  msg.packet_type.msgt_number = packet->length;

  return deliver_msg (&msg, vdev);
}

/* Broadcast the message to all virtual interfaces. */
int 
broadcast_msg (struct net_rcv_msg *msg)
{
  int rval = 0;
  mach_msg_header_t header;

  int internal_deliver_msg (struct vether_device *vdev)
    {
      return deliver_msg (msg, vdev);
    }

  /* Save the message header because deliver_msg will change it. */
  header = msg->msg_hdr;
  rval = foreach_dev_do (internal_deliver_msg);
  msg->msg_hdr = header;
  return rval;
}

/*
 * Deliver the message to all right pfinet servers that
 * connects to the virtual network interface.
 */
int
deliver_msg(struct net_rcv_msg *msg, struct vether_device *vdev)
{
  mach_msg_return_t err;
  queue_head_t *if_port_list;
  net_rcv_port_t infp, nextfp;

  msg->msg_hdr.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_COPY_SEND, 0);
  /* remember message sizes must be rounded up */
  msg->msg_hdr.msgh_local_port = MACH_PORT_NULL;
  msg->msg_hdr.msgh_kind = MACH_MSGH_KIND_NORMAL;
  msg->msg_hdr.msgh_id = NET_RCV_MSG_ID;

  if_port_list = &vdev->port_list.if_rcv_port_list;
  FILTER_ITERATE (if_port_list, infp, nextfp, &infp->input) 
    {
      mach_port_t dest;
      net_hash_entry_t entp, *hash_headp;
      int ret_count;

      entp = (net_hash_entry_t) 0;
      ret_count = bpf_do_filter (infp,
				 msg->packet + sizeof (struct packet_header),
				 msg->net_rcv_msg_packet_count, msg->header,
				 sizeof (struct ethhdr), &hash_headp, &entp);
      if (entp == (net_hash_entry_t) 0)
	dest = infp->rcv_port;
      else
	dest = entp->rcv_port;

      if (ret_count) 
	{
	  debug ("before delivering the packet\n");
	  msg->msg_hdr.msgh_remote_port = dest;
	  err = mach_msg ((mach_msg_header_t *)msg,
			  MACH_SEND_MSG|MACH_SEND_TIMEOUT,
			  msg->msg_hdr.msgh_size, 0, MACH_PORT_NULL,
			  0, MACH_PORT_NULL);
	  if (err != MACH_MSG_SUCCESS)
	    {
	      mach_port_deallocate(mach_task_self (),
				   ((mach_msg_header_t *)msg)->msgh_remote_port);
	      error (0, err, "mach_msg");
	      return -1;
	    }
	  debug ("after delivering the packet\n");
	}
    }
  FILTER_ITERATE_END

    return 0;
}