/*
   Copyright (C) 1995, 1996, 1998, 1999, 2000, 2002, 2007, 2017
     Free Software Foundation, Inc.

   Written by Michael I. Bushnell, p/BSG.

   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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
*/

/* Ethernet devices module */

#include <netif/hurdethif.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <pthread.h>
#include <error.h>
#include <device/device.h>
#include <device/net_status.h>
#include <net/if.h>
#include <net/if_arp.h>

#include <lwip/opt.h>
#include <lwip/def.h>
#include <lwip/mem.h>
#include <lwip/pbuf.h>
#include <lwip/stats.h>
#include <lwip/snmp.h>
#include <lwip/ethip6.h>
#include <lwip/etharp.h>
#include <lwip/sockets.h>
#include <lwip/inet.h>

/* Get the MAC address from an array of int */
#define GET_HWADDR_BYTE(x,n)  (((char*)x)[n])

static short ether_filter[] = {
#ifdef NETF_IN
  /* We have to tell the packet filtering code that we're interested in
     incoming packets.  */
  NETF_IN,			/* Header.  */
#endif
  NETF_PUSHLIT | NETF_NOP,
  1
};

static int ether_filter_len = sizeof (ether_filter) / sizeof (short);

static struct bpf_insn bpf_ether_filter[] = {
  {NETF_IN | NETF_BPF, 0, 0, 0},	/* Header. */
  {BPF_LD | BPF_H | BPF_ABS, 0, 0, 12},	/* Load Ethernet type */
  {BPF_JMP | BPF_JEQ | BPF_K, 2, 0, 0x0806},	/* Accept ARP */
  {BPF_JMP | BPF_JEQ | BPF_K, 1, 0, 0x0800},	/* Accept IPv4 */
  {BPF_JMP | BPF_JEQ | BPF_K, 0, 1, 0x86DD},	/* Accept IPv6 */
  /*
   * And return an amount of bytes equal to:
   * MSS + IP and transport headers length + Ethernet header length
   */
  {BPF_RET | BPF_K, 0, 0, TCP_MSS + 0x28 + PBUF_LINK_HLEN},
  {BPF_RET | BPF_K, 0, 0, 0},	/* Or discard it all */
};

static int bpf_ether_filter_len = sizeof (bpf_ether_filter) / (sizeof (short));

/* Bucket and class for the incoming data */
struct port_bucket *etherport_bucket;
struct port_class *etherread_class;

/* Thread for the incoming data */
static pthread_t input_thread;

/* Get the device flags */
static error_t
hurdethif_device_get_flags (struct netif *netif, uint16_t * flags)
{
  error_t err = 0;
  mach_msg_type_number_t count;
  struct net_status status;
  hurdethif *ethif;

  memset (&status, 0, sizeof (struct net_status));

  ethif = netif_get_state (netif);
  count = NET_STATUS_COUNT;
  err = device_get_status (ethif->ether_port,
			   NET_STATUS, (dev_status_t) & status, &count);
  if (err == D_INVALID_OPERATION)
    {
      /*
       * eth-multiplexer doesn't support setting flags.
       * We must ignore D_INVALID_OPERATION.
       */
      error (0, 0, "%s: hardware doesn't support getting flags.\n",
	     ethif->devname);
      err = 0;
    }
  else if (err)
    error (0, err, "%s: Cannot get hardware flags", ethif->devname);
  else
    *flags = status.flags;

  return err;
}

/* Set the device flags */
static error_t
hurdethif_device_set_flags (struct netif *netif, uint16_t flags)
{
  error_t err = 0;
  hurdethif *ethif;
  int sflags;

  sflags = flags;
  ethif = netif_get_state (netif);

  if (ethif->ether_port == MACH_PORT_NULL)
    /* The device is closed */
    return 0;

  err = device_set_status (ethif->ether_port, NET_FLAGS, &sflags, 1);
  if (err == D_INVALID_OPERATION)
    {
      /*
       * eth-multiplexer doesn't support setting flags.
       * We must ignore D_INVALID_OPERATION.
       */
      error (0, 0, "%s: hardware doesn't support setting flags.\n",
	     ethif->devname);
      err = 0;
    }
  else if (err)
    error (0, err, "%s: Cannot set hardware flags", ethif->devname);
  else
    ethif->flags = flags;

  return err;
}

/* Use the device interface to access the device */
static error_t
hurdethif_device_open (struct netif *netif)
{
  error_t err = ERR_OK;
  device_t master_device;
  hurdethif *ethif = netif_get_state (netif);

  if (ethif->ether_port != MACH_PORT_NULL)
    {
      error (0, 0, "Already opened: %s", ethif->devname);
      return -1;
    }

  err = ports_create_port (etherread_class, etherport_bucket,
			   sizeof (struct port_info), &ethif->readpt);
  if (err)
    {
      error (0, err, "ports_create_port on %s", ethif->devname);
    }
  else
    {
      ethif->readptname = ports_get_right (ethif->readpt);
      mach_port_insert_right (mach_task_self (), ethif->readptname,
			      ethif->readptname, MACH_MSG_TYPE_MAKE_SEND);

      mach_port_set_qlimit (mach_task_self (), ethif->readptname,
			    MACH_PORT_QLIMIT_MAX);

      master_device = file_name_lookup (ethif->devname, O_RDWR, 0);
      if (master_device != MACH_PORT_NULL)
	{
	  /* The device name here is the path of a device file.  */
	  err = device_open (master_device, D_WRITE | D_READ,
			     "eth", &ethif->ether_port);
	  mach_port_deallocate (mach_task_self (), master_device);
	  if (err)
	    error (0, err, "device_open on %s", ethif->devname);
	  else
	    {
	      err = device_set_filter (ethif->ether_port, ethif->readptname,
				       MACH_MSG_TYPE_MAKE_SEND, 0,
				       (filter_array_t) bpf_ether_filter,
				       bpf_ether_filter_len);
	      if (err)
		error (0, err, "device_set_filter on %s", ethif->devname);
	    }
	}
      else
	{
	  /* No, perhaps a Mach device?  */
	  int file_errno = errno;
	  err = get_privileged_ports (0, &master_device);
	  if (err)
	    {
	      error (0, file_errno, "file_name_lookup %s", ethif->devname);
	      error (0, err, "and cannot get device master port");
	    }
	  else
	    {
	      err = device_open (master_device, D_WRITE | D_READ,
				 ethif->devname, &ethif->ether_port);
	      mach_port_deallocate (mach_task_self (), master_device);
	      if (err)
		{
		  error (0, file_errno, "file_name_lookup %s",
			 ethif->devname);
		  error (0, err, "device_open(%s)", ethif->devname);
		}
	      else
		{
		  err =
		    device_set_filter (ethif->ether_port, ethif->readptname,
				       MACH_MSG_TYPE_MAKE_SEND, 0,
				       (filter_array_t) ether_filter,
				       ether_filter_len);
		  if (err)
		    error (0, err, "device_set_filter on %s", ethif->devname);
		}
	    }
	}
    }

  return err;
}

/* Destroy our link to the device */
static error_t
hurdethif_device_close (struct netif *netif)
{
  hurdethif *ethif = netif_get_state (netif);

  if (ethif->ether_port == MACH_PORT_NULL)
    {
      error (0, 0, "Already closed: %s", ethif->devname);
      return -1;
    }

  mach_port_deallocate (mach_task_self (), ethif->readptname);
  ethif->readptname = MACH_PORT_NULL;
  ports_destroy_right (ethif->readpt);
  ethif->readpt = NULL;
  device_close (ethif->ether_port);
  mach_port_deallocate (mach_task_self (), ethif->ether_port);
  ethif->ether_port = MACH_PORT_NULL;

  return ERR_OK;
}

/*
 * Called from lwip when outgoing data is ready
 */
static err_t
hurdethif_output (struct netif *netif, struct pbuf *p)
{
  error_t err;
  hurdethif *ethif = netif_get_state (netif);
  int count;
  uint8_t tried;

  if (p->tot_len != p->len)
    /* Drop the packet */
    return ERR_OK;

  tried = 0;
  /* Send the data from the pbuf to the interface, one pbuf at a
     time. The size of the data in each pbuf is kept in the ->len
     variable. */
  do
    {
      tried++;
      err = device_write (ethif->ether_port, D_NOWAIT, 0,
			  p->payload, p->len, &count);
      if (err)
	{
	  if (tried == 2)
	    /* Too many tries, abort */
	    break;

	  if (err == EMACH_SEND_INVALID_DEST || err == EMIG_SERVER_DIED)
	    {
	      /* Device probably just died, try to reopen it.  */
	      hurdethif_device_close (netif);
	      hurdethif_device_open (netif);
	    }
	}
      else if (count != p->len)
	/* Incomplete package sent, reattempt */
	err = -1;
    }
  while (err);

  return ERR_OK;
}

/*
 * Called from the demuxer when incoming data is ready
 */
void
hurdethif_input (struct netif *netif, struct net_rcv_msg *msg)
{
  struct pbuf *p, *q;
  uint16_t len;
  uint16_t off;
  uint16_t next_read;

  /* Get the size of the whole packet */
  len = PBUF_LINK_HLEN
    + msg->packet_type.msgt_number - sizeof (struct packet_header);

  /* Allocate an empty pbuf chain for the data */
  p = pbuf_alloc (PBUF_RAW, len, PBUF_POOL);

  if (p)
    {
      /*
       * Iterate to fill the pbuf chain.
       * 
       * First read the Ethernet header from msg->header. Then read the
       * payload from msg->packet
       */
      q = p;
      off = 0;
      do
	{
	  if (off < PBUF_LINK_HLEN)
	    {
	      /* We still haven't ended copying the header */
	      next_read = (off + q->len) > PBUF_LINK_HLEN ?
		(PBUF_LINK_HLEN - off) : q->len;
	      memcpy (q->payload, msg->header + off, next_read);

	      if ((off + q->len) > PBUF_LINK_HLEN)
		memcpy (q->payload + PBUF_LINK_HLEN,
			msg->packet + sizeof (struct packet_header),
			q->len - next_read);
	    }
	  else
	    /* The header is copyied yet */
	    memcpy (q->payload, msg->packet +
		    sizeof (struct packet_header) + off - PBUF_LINK_HLEN,
		    q->len);

	  off += q->len;

	  /* q->tot_len == q->len means this was the last pbuf in the chain */
	  if (q->tot_len == q->len)
	    break;
	  else
	    q = q->next;
	}
      while (1);

      /* Pass the pbuf chain to he input function */
      if (netif->input (p, netif) != ERR_OK)
	{
	  LWIP_DEBUGF (NETIF_DEBUG, ("hurdethif_input: IP input error\n"));
	  pbuf_free (p);
	  p = NULL;
	}
    }
}

/* Demux incoming RPCs from the device */
int
hurdethif_demuxer (mach_msg_header_t * inp, mach_msg_header_t * outp)
{
  struct net_rcv_msg *msg = (struct net_rcv_msg *) inp;
  struct netif *netif;
  mach_port_t local_port;

  if (inp->msgh_id != NET_RCV_MSG_ID)
    return 0;

  if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) ==
      MACH_MSG_TYPE_PROTECTED_PAYLOAD)
    {
      struct port_info *pi = ports_lookup_payload (NULL,
						   inp->msgh_protected_payload,
						   NULL);
      if (pi)
	{
	  local_port = pi->port_right;
	  ports_port_deref (pi);
	}
      else
	local_port = MACH_PORT_NULL;
    }
  else
    local_port = inp->msgh_local_port;

  NETIF_FOREACH(netif)
    if (local_port == netif_get_state (netif)->readptname)
      break;

  if (!netif)
    {
      if (inp->msgh_remote_port != MACH_PORT_NULL)
	mach_port_deallocate (mach_task_self (), inp->msgh_remote_port);
      return 1;
    }

  hurdethif_input (netif, msg);

  return 1;
}

/*
 * Update the interface's MTU and the BPF filter
 */
static error_t
hurdethif_device_update_mtu (struct netif *netif, uint32_t mtu)
{
  error_t err = 0;

  netif->mtu = mtu;

  bpf_ether_filter[5].k = mtu + PBUF_LINK_HLEN;

  return err;
}

/*
 * Release all resources of this netif.
 *
 * Returns 0 on success.
 */
static error_t
hurdethif_device_terminate (struct netif *netif)
{
  /* Free the hook */
  free (netif_get_state (netif)->devname);
  free (netif_get_state (netif));

  return 0;
}

/*
 * Initializes a single device.
 * 
 * The module must be initialized before calling this function.
 */
err_t
hurdethif_device_init (struct netif *netif)
{
  error_t err;
  mach_msg_type_number_t count = 2;
  int net_address[2];
  device_t ether_port;
  hurdethif *ethif;

  /*
   * Replace the hook by a new one with the proper size.
   * The old one is in the stack and will be removed soon.
   */
  ethif = calloc (1, sizeof (hurdethif));
  if (!ethif)
    {
      LWIP_DEBUGF (NETIF_DEBUG, ("hurdethif_init: out of memory\n"));
      return ERR_MEM;
    }
  memcpy (ethif, netif_get_state (netif), sizeof (struct ifcommon));
  netif->state = ethif;

  /* Interface type */
  ethif->type = ARPHRD_ETHER;

  /* Set callbacks */
  netif->output = etharp_output;
  netif->output_ip6 = ethip6_output;
  netif->linkoutput = hurdethif_output;

  ethif->open = hurdethif_device_open;
  ethif->close = hurdethif_device_close;
  ethif->terminate = hurdethif_device_terminate;
  ethif->update_mtu = hurdethif_device_update_mtu;
  ethif->change_flags = hurdethif_device_set_flags;

  /* ---- Hardware initialization ---- */

  /* We need the device to be opened to configure it */
  err = hurdethif_device_open (netif);
  if (err)
    return ERR_IF;

  /* Get the MAC address */
  ether_port = netif_get_state (netif)->ether_port;
  err = device_get_status (ether_port, NET_ADDRESS, net_address, &count);
  if (err)
    error (0, err, "%s: Cannot get hardware Ethernet address",
	   netif_get_state (netif)->devname);
  else if (count * sizeof (int) >= ETHARP_HWADDR_LEN)
    {
      net_address[0] = ntohl (net_address[0]);
      net_address[1] = ntohl (net_address[1]);

      /* Set MAC hardware address length */
      netif->hwaddr_len = ETHARP_HWADDR_LEN;

      /* Set MAC hardware address */
      netif->hwaddr[0] = GET_HWADDR_BYTE (net_address, 0);
      netif->hwaddr[1] = GET_HWADDR_BYTE (net_address, 1);
      netif->hwaddr[2] = GET_HWADDR_BYTE (net_address, 2);
      netif->hwaddr[3] = GET_HWADDR_BYTE (net_address, 3);
      netif->hwaddr[4] = GET_HWADDR_BYTE (net_address, 4);
      netif->hwaddr[5] = GET_HWADDR_BYTE (net_address, 5);
    }
  else
    error (0, 0, "%s: Invalid Ethernet address",
	   netif_get_state (netif)->devname);

  /* Maximum transfer unit: MSS + IP header size + TCP header size */
  netif->mtu = TCP_MSS + 20 + 20;

  /* Enable Ethernet multicasting */
  hurdethif_device_get_flags (netif, &netif_get_state (netif)->flags);
  netif_get_state (netif)->flags |=
    IFF_UP | IFF_RUNNING | IFF_BROADCAST | IFF_ALLMULTI;
  hurdethif_device_set_flags (netif, netif_get_state (netif)->flags);

  /*
   * Up the link, set the interface type to NETIF_FLAG_ETHARP
   * and enable other features.
   */
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP
    | NETIF_FLAG_IGMP | NETIF_FLAG_MLD6;

  return ERR_OK;
}

static void *
hurdethif_input_thread (void *arg)
{
  ports_manage_port_operations_one_thread (etherport_bucket,
					   hurdethif_demuxer, 0);

  return 0;
}

/*
 * Init the thread for the incoming data.
 *
 * This function should be called once.
 */
error_t
hurdethif_module_init (void)
{
  error_t err;
  etherport_bucket = ports_create_bucket ();
  etherread_class = ports_create_class (0, 0);

  err = pthread_create (&input_thread, 0, hurdethif_input_thread, 0);
  if (!err)
    pthread_detach (input_thread);
  else
    {
      errno = err;
      perror ("pthread_create");
    }

  return err;
}