/*

   * IEEE 802.15.4 dgram socket interface

   *
   * Copyright 2007, 2008 Siemens AG
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2
   * as published by the Free Software Foundation.
   *
   * This program 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.,
   * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Written by:
   * Sergey Lapin <slapin@ossfans.org>
   * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
   */
  
  #include <linux/net.h>
  #include <linux/module.h>
  #include <linux/if_arp.h>
  #include <linux/list.h>

  #include <linux/slab.h>

  #include <net/sock.h>

  #include <net/af_ieee802154.h>
  #include <net/ieee802154.h>
  #include <net/ieee802154_netdev.h>

  
  #include <asm/ioctls.h>
  
  #include "af802154.h"
  
  static HLIST_HEAD(dgram_head);
  static DEFINE_RWLOCK(dgram_lock);
  
  struct dgram_sock {
  	struct sock sk;

  	struct ieee802154_addr src_addr;
  	struct ieee802154_addr dst_addr;

  	unsigned int bound:1;
  	unsigned int want_ack:1;

  };
  
  static inline struct dgram_sock *dgram_sk(const struct sock *sk)
  {
  	return container_of(sk, struct dgram_sock, sk);
  }

  static void dgram_hash(struct sock *sk)
  {
  	write_lock_bh(&dgram_lock);
  	sk_add_node(sk, &dgram_head);
  	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
  	write_unlock_bh(&dgram_lock);
  }
  
  static void dgram_unhash(struct sock *sk)
  {
  	write_lock_bh(&dgram_lock);
  	if (sk_del_node_init(sk))
  		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
  	write_unlock_bh(&dgram_lock);
  }
  
  static int dgram_init(struct sock *sk)
  {
  	struct dgram_sock *ro = dgram_sk(sk);
  
  	ro->dst_addr.addr_type = IEEE802154_ADDR_LONG;
  	ro->dst_addr.pan_id = 0xffff;

  	ro->want_ack = 1;

  	memset(&ro->dst_addr.hwaddr, 0xff, sizeof(ro->dst_addr.hwaddr));
  	return 0;
  }
  
  static void dgram_close(struct sock *sk, long timeout)
  {
  	sk_common_release(sk);
  }
  
  static int dgram_bind(struct sock *sk, struct sockaddr *uaddr, int len)
  {
  	struct sockaddr_ieee802154 *addr = (struct sockaddr_ieee802154 *)uaddr;
  	struct dgram_sock *ro = dgram_sk(sk);

  	int err = -EINVAL;

  	struct net_device *dev;

  	lock_sock(sk);

  	ro->bound = 0;
  
  	if (len < sizeof(*addr))

  		goto out;

  
  	if (addr->family != AF_IEEE802154)

  		goto out;

  
  	dev = ieee802154_get_dev(sock_net(sk), &addr->addr);
  	if (!dev) {
  		err = -ENODEV;
  		goto out;
  	}
  
  	if (dev->type != ARPHRD_IEEE802154) {
  		err = -ENODEV;
  		goto out_put;
  	}
  
  	memcpy(&ro->src_addr, &addr->addr, sizeof(struct ieee802154_addr));
  
  	ro->bound = 1;

  	err = 0;

  out_put:
  	dev_put(dev);
  out:
  	release_sock(sk);
  
  	return err;
  }
  
  static int dgram_ioctl(struct sock *sk, int cmd, unsigned long arg)
  {
  	switch (cmd) {
  	case SIOCOUTQ:
  	{

  		int amount = sk_wmem_alloc_get(sk);

  		return put_user(amount, (int __user *)arg);
  	}
  
  	case SIOCINQ:
  	{
  		struct sk_buff *skb;
  		unsigned long amount;
  
  		amount = 0;
  		spin_lock_bh(&sk->sk_receive_queue.lock);
  		skb = skb_peek(&sk->sk_receive_queue);
  		if (skb != NULL) {
  			/*
  			 * We will only return the amount
  			 * of this packet since that is all
  			 * that will be read.
  			 */
  			/* FIXME: parse the header for more correct value */
  			amount = skb->len - (3+8+8);
  		}
  		spin_unlock_bh(&sk->sk_receive_queue.lock);
  		return put_user(amount, (int __user *)arg);
  	}
  
  	}
  	return -ENOIOCTLCMD;
  }
  
  /* FIXME: autobind */
  static int dgram_connect(struct sock *sk, struct sockaddr *uaddr,
  			int len)
  {
  	struct sockaddr_ieee802154 *addr = (struct sockaddr_ieee802154 *)uaddr;
  	struct dgram_sock *ro = dgram_sk(sk);
  	int err = 0;
  
  	if (len < sizeof(*addr))
  		return -EINVAL;
  
  	if (addr->family != AF_IEEE802154)
  		return -EINVAL;
  
  	lock_sock(sk);
  
  	if (!ro->bound) {
  		err = -ENETUNREACH;
  		goto out;
  	}
  
  	memcpy(&ro->dst_addr, &addr->addr, sizeof(struct ieee802154_addr));
  
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int dgram_disconnect(struct sock *sk, int flags)
  {
  	struct dgram_sock *ro = dgram_sk(sk);
  
  	lock_sock(sk);
  
  	ro->dst_addr.addr_type = IEEE802154_ADDR_LONG;
  	memset(&ro->dst_addr.hwaddr, 0xff, sizeof(ro->dst_addr.hwaddr));
  
  	release_sock(sk);
  
  	return 0;
  }
  
  static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
  		struct msghdr *msg, size_t size)
  {
  	struct net_device *dev;

  	unsigned int mtu;

  	struct sk_buff *skb;
  	struct dgram_sock *ro = dgram_sk(sk);

  	int hlen, tlen;

  	int err;
  
  	if (msg->msg_flags & MSG_OOB) {
  		pr_debug("msg->msg_flags = 0x%x
  ", msg->msg_flags);
  		return -EOPNOTSUPP;
  	}
  
  	if (!ro->bound)
  		dev = dev_getfirstbyhwtype(sock_net(sk), ARPHRD_IEEE802154);
  	else
  		dev = ieee802154_get_dev(sock_net(sk), &ro->src_addr);
  
  	if (!dev) {
  		pr_debug("no dev
  ");
  		err = -ENXIO;
  		goto out;
  	}
  	mtu = dev->mtu;
  	pr_debug("name = %s, mtu = %u
  ", dev->name, mtu);

  	if (size > mtu) {
  		pr_debug("size = %Zu, mtu = %u
  ", size, mtu);
  		err = -EINVAL;
  		goto out_dev;
  	}

  	hlen = LL_RESERVED_SPACE(dev);
  	tlen = dev->needed_tailroom;
  	skb = sock_alloc_send_skb(sk, hlen + tlen + size,

  			msg->msg_flags & MSG_DONTWAIT,
  			&err);
  	if (!skb)
  		goto out_dev;

  	skb_reserve(skb, hlen);

  
  	skb_reset_network_header(skb);

  	mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
  	if (ro->want_ack)
  		mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;

  	mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
  	err = dev_hard_header(skb, dev, ETH_P_IEEE802154, &ro->dst_addr,
  			ro->bound ? &ro->src_addr : NULL, size);
  	if (err < 0)
  		goto out_skb;
  
  	skb_reset_mac_header(skb);
  
  	err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
  	if (err < 0)
  		goto out_skb;

  	skb->dev = dev;
  	skb->sk  = sk;
  	skb->protocol = htons(ETH_P_IEEE802154);
  
  	dev_put(dev);
  
  	err = dev_queue_xmit(skb);
  	if (err > 0)
  		err = net_xmit_errno(err);
  
  	return err ?: size;
  
  out_skb:
  	kfree_skb(skb);
  out_dev:
  	dev_put(dev);
  out:
  	return err;
  }
  
  static int dgram_recvmsg(struct kiocb *iocb, struct sock *sk,
  		struct msghdr *msg, size_t len, int noblock, int flags,
  		int *addr_len)
  {
  	size_t copied = 0;
  	int err = -EOPNOTSUPP;
  	struct sk_buff *skb;

  	struct sockaddr_ieee802154 *saddr;
  
  	saddr = (struct sockaddr_ieee802154 *)msg->msg_name;

  
  	skb = skb_recv_datagram(sk, flags, noblock, &err);
  	if (!skb)
  		goto out;
  
  	copied = skb->len;
  	if (len < copied) {
  		msg->msg_flags |= MSG_TRUNC;
  		copied = len;
  	}
  
  	/* FIXME: skip headers if necessary ?! */
  	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
  	if (err)
  		goto done;

  	sock_recv_ts_and_drops(msg, sk, skb);

  	if (saddr) {
  		saddr->family = AF_IEEE802154;
  		saddr->addr = mac_cb(skb)->sa;
  	}
  	if (addr_len)
  		*addr_len = sizeof(*saddr);

  	if (flags & MSG_TRUNC)
  		copied = skb->len;
  done:
  	skb_free_datagram(sk, skb);
  out:
  	if (err)
  		return err;
  	return copied;
  }
  
  static int dgram_rcv_skb(struct sock *sk, struct sk_buff *skb)
  {
  	if (sock_queue_rcv_skb(sk, skb) < 0) {

  		kfree_skb(skb);
  		return NET_RX_DROP;
  	}
  
  	return NET_RX_SUCCESS;
  }
  
  static inline int ieee802154_match_sock(u8 *hw_addr, u16 pan_id,
  		u16 short_addr, struct dgram_sock *ro)
  {
  	if (!ro->bound)
  		return 1;
  
  	if (ro->src_addr.addr_type == IEEE802154_ADDR_LONG &&
  	    !memcmp(ro->src_addr.hwaddr, hw_addr, IEEE802154_ADDR_LEN))
  		return 1;
  
  	if (ro->src_addr.addr_type == IEEE802154_ADDR_SHORT &&
  		     pan_id == ro->src_addr.pan_id &&
  		     short_addr == ro->src_addr.short_addr)
  		return 1;
  
  	return 0;
  }
  
  int ieee802154_dgram_deliver(struct net_device *dev, struct sk_buff *skb)
  {
  	struct sock *sk, *prev = NULL;

  	int ret = NET_RX_SUCCESS;
  	u16 pan_id, short_addr;
  
  	/* Data frame processing */
  	BUG_ON(dev->type != ARPHRD_IEEE802154);
  
  	pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
  	short_addr = ieee802154_mlme_ops(dev)->get_short_addr(dev);
  
  	read_lock(&dgram_lock);

  	sk_for_each(sk, &dgram_head) {

  		if (ieee802154_match_sock(dev->dev_addr, pan_id, short_addr,
  					dgram_sk(sk))) {
  			if (prev) {
  				struct sk_buff *clone;
  				clone = skb_clone(skb, GFP_ATOMIC);
  				if (clone)
  					dgram_rcv_skb(prev, clone);
  			}
  
  			prev = sk;
  		}
  	}
  
  	if (prev)
  		dgram_rcv_skb(prev, skb);
  	else {
  		kfree_skb(skb);
  		ret = NET_RX_DROP;
  	}
  	read_unlock(&dgram_lock);
  
  	return ret;
  }

  static int dgram_getsockopt(struct sock *sk, int level, int optname,
  		    char __user *optval, int __user *optlen)
  {

  	struct dgram_sock *ro = dgram_sk(sk);
  
  	int val, len;
  
  	if (level != SOL_IEEE802154)
  		return -EOPNOTSUPP;
  
  	if (get_user(len, optlen))
  		return -EFAULT;
  
  	len = min_t(unsigned int, len, sizeof(int));
  
  	switch (optname) {
  	case WPAN_WANTACK:
  		val = ro->want_ack;
  		break;
  	default:
  		return -ENOPROTOOPT;
  	}
  
  	if (put_user(len, optlen))
  		return -EFAULT;
  	if (copy_to_user(optval, &val, len))
  		return -EFAULT;
  	return 0;

  }
  
  static int dgram_setsockopt(struct sock *sk, int level, int optname,

  		    char __user *optval, unsigned int optlen)

  {

  	struct dgram_sock *ro = dgram_sk(sk);
  	int val;
  	int err = 0;
  
  	if (optlen < sizeof(int))
  		return -EINVAL;
  
  	if (get_user(val, (int __user *)optval))
  		return -EFAULT;
  
  	lock_sock(sk);
  
  	switch (optname) {
  	case WPAN_WANTACK:
  		ro->want_ack = !!val;
  		break;
  	default:
  		err = -ENOPROTOOPT;
  		break;
  	}
  
  	release_sock(sk);
  	return err;

  }

  struct proto ieee802154_dgram_prot = {
  	.name		= "IEEE-802.15.4-MAC",
  	.owner		= THIS_MODULE,
  	.obj_size	= sizeof(struct dgram_sock),
  	.init		= dgram_init,
  	.close		= dgram_close,
  	.bind		= dgram_bind,
  	.sendmsg	= dgram_sendmsg,
  	.recvmsg	= dgram_recvmsg,
  	.hash		= dgram_hash,
  	.unhash		= dgram_unhash,
  	.connect	= dgram_connect,
  	.disconnect	= dgram_disconnect,
  	.ioctl		= dgram_ioctl,

  	.getsockopt	= dgram_getsockopt,
  	.setsockopt	= dgram_setsockopt,

  };