/*
   * Copyright 2011, Siemens AG
   * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
   */
  
  /*
   * Based on patches from Jon Smirl <jonsmirl@gmail.com>
   * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
   *
   * 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.
   */
  
  /* Jon's code is based on 6lowpan implementation for Contiki which is:
   * Copyright (c) 2008, Swedish Institute of Computer Science.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #ifndef __6LOWPAN_H__
  #define __6LOWPAN_H__

  #include <linux/debugfs.h>

  #include <net/ipv6.h>

  #include <net/net_namespace.h>

  /* special link-layer handling */
  #include <net/mac802154.h>

  #define EUI64_ADDR_LEN		8

  #define LOWPAN_NHC_MAX_ID_LEN	1

  /* Maximum next header compression length which we currently support inclusive
   * possible inline data.
   */
  #define LOWPAN_NHC_MAX_HDR_LEN	(sizeof(struct udphdr))

  /* Max IPHC Header len without IPv6 hdr specific inline data.
   * Useful for getting the "extra" bytes we need at worst case compression.
   *
   * LOWPAN_IPHC + CID + LOWPAN_NHC_MAX_ID_LEN
   */
  #define LOWPAN_IPHC_MAX_HEADER_LEN	(2 + 1 + LOWPAN_NHC_MAX_ID_LEN)

  /* Maximum worst case IPHC header buffer size */
  #define LOWPAN_IPHC_MAX_HC_BUF_LEN	(sizeof(struct ipv6hdr) +	\
  					 LOWPAN_IPHC_MAX_HEADER_LEN +	\
  					 LOWPAN_NHC_MAX_HDR_LEN)

  /* SCI/DCI is 4 bit width, so we have maximum 16 entries */
  #define LOWPAN_IPHC_CTX_TABLE_SIZE	(1 << 4)

  #define LOWPAN_DISPATCH_IPV6		0x41 /* 01000001 = 65 */
  #define LOWPAN_DISPATCH_IPHC		0x60 /* 011xxxxx = ... */
  #define LOWPAN_DISPATCH_IPHC_MASK	0xe0

  static inline bool lowpan_is_ipv6(u8 dispatch)
  {
  	return dispatch == LOWPAN_DISPATCH_IPV6;
  }
  
  static inline bool lowpan_is_iphc(u8 dispatch)
  {
  	return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;
  }

  #define LOWPAN_PRIV_SIZE(llpriv_size)	\

  	(sizeof(struct lowpan_dev) + llpriv_size)

  
  enum lowpan_lltypes {
  	LOWPAN_LLTYPE_BTLE,
  	LOWPAN_LLTYPE_IEEE802154,
  };

  enum lowpan_iphc_ctx_flags {
  	LOWPAN_IPHC_CTX_FLAG_ACTIVE,
  	LOWPAN_IPHC_CTX_FLAG_COMPRESSION,
  };
  
  struct lowpan_iphc_ctx {
  	u8 id;
  	struct in6_addr pfx;
  	u8 plen;
  	unsigned long flags;
  };
  
  struct lowpan_iphc_ctx_table {
  	spinlock_t lock;
  	const struct lowpan_iphc_ctx_ops *ops;
  	struct lowpan_iphc_ctx table[LOWPAN_IPHC_CTX_TABLE_SIZE];
  };
  
  static inline bool lowpan_iphc_ctx_is_active(const struct lowpan_iphc_ctx *ctx)
  {
  	return test_bit(LOWPAN_IPHC_CTX_FLAG_ACTIVE, &ctx->flags);
  }
  
  static inline bool
  lowpan_iphc_ctx_is_compression(const struct lowpan_iphc_ctx *ctx)
  {
  	return test_bit(LOWPAN_IPHC_CTX_FLAG_COMPRESSION, &ctx->flags);
  }

  struct lowpan_dev {

  	enum lowpan_lltypes lltype;

  	struct dentry *iface_debugfs;

  	struct lowpan_iphc_ctx_table ctx;

  
  	/* must be last */
  	u8 priv[0] __aligned(sizeof(void *));
  };

  struct lowpan_802154_neigh {
  	__le16 short_addr;
  };
  
  static inline
  struct lowpan_802154_neigh *lowpan_802154_neigh(void *neigh_priv)
  {
  	return neigh_priv;
  }

  static inline

  struct lowpan_dev *lowpan_dev(const struct net_device *dev)

  {
  	return netdev_priv(dev);
  }

  /* private device info */
  struct lowpan_802154_dev {
  	struct net_device	*wdev; /* wpan device ptr */
  	u16			fragment_tag;
  };
  
  static inline struct
  lowpan_802154_dev *lowpan_802154_dev(const struct net_device *dev)
  {
  	return (struct lowpan_802154_dev *)lowpan_dev(dev)->priv;
  }

  struct lowpan_802154_cb {
  	u16 d_tag;
  	unsigned int d_size;
  	u8 d_offset;
  };
  
  static inline
  struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)
  {
  	BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb));
  	return (struct lowpan_802154_cb *)skb->cb;
  }

  static inline void lowpan_iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
  						       const void *lladdr)
  {
  	/* fe:80::XXXX:XXXX:XXXX:XXXX
  	 *        \_________________/
  	 *              hwaddr
  	 */
  	ipaddr->s6_addr[0] = 0xFE;
  	ipaddr->s6_addr[1] = 0x80;
  	memcpy(&ipaddr->s6_addr[8], lladdr, EUI64_ADDR_LEN);
  	/* second bit-flip (Universe/Local)
  	 * is done according RFC2464
  	 */
  	ipaddr->s6_addr[8] ^= 0x02;
  }

  static inline void lowpan_iphc_uncompress_eui48_lladdr(struct in6_addr *ipaddr,
  						       const void *lladdr)
  {
  	/* fe:80::XXXX:XXff:feXX:XXXX
  	 *        \_________________/
  	 *              hwaddr
  	 */
  	ipaddr->s6_addr[0] = 0xFE;
  	ipaddr->s6_addr[1] = 0x80;
  	memcpy(&ipaddr->s6_addr[8], lladdr, 3);
  	ipaddr->s6_addr[11] = 0xFF;
  	ipaddr->s6_addr[12] = 0xFE;
  	memcpy(&ipaddr->s6_addr[13], lladdr + 3, 3);

  }

  #ifdef DEBUG
  /* print data in line */
  static inline void raw_dump_inline(const char *caller, char *msg,

  				   const unsigned char *buf, int len)

  {
  	if (msg)
  		pr_debug("%s():%s: ", caller, msg);
  
  	print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, buf, len, false);
  }
  
  /* print data in a table format:
   *
   * addr: xx xx xx xx xx xx
   * addr: xx xx xx xx xx xx
   * ...
   */
  static inline void raw_dump_table(const char *caller, char *msg,

  				  const unsigned char *buf, int len)

  {
  	if (msg)
  		pr_debug("%s():%s:
  ", caller, msg);
  
  	print_hex_dump_debug("\t", DUMP_PREFIX_OFFSET, 16, 1, buf, len, false);
  }
  #else
  static inline void raw_dump_table(const char *caller, char *msg,

  				  const unsigned char *buf, int len) { }

  static inline void raw_dump_inline(const char *caller, char *msg,

  				   const unsigned char *buf, int len) { }

  #endif

  /**
   * lowpan_fetch_skb - getting inline data from 6LoWPAN header
   *
   * This function will pull data from sk buffer and put it into data to
   * remove the 6LoWPAN inline data. This function returns true if the
   * sk buffer is too small to pull the amount of data which is specified
   * by len.
   *
   * @skb: the buffer where the inline data should be pulled from.
   * @data: destination buffer for the inline data.
   * @len: amount of data which should be pulled in bytes.
   */
  static inline bool lowpan_fetch_skb(struct sk_buff *skb, void *data,
  				    unsigned int len)

  {
  	if (unlikely(!pskb_may_pull(skb, len)))
  		return true;
  
  	skb_copy_from_linear_data(skb, data, len);
  	skb_pull(skb, len);
  
  	return false;
  }

  static inline bool lowpan_802154_is_valid_src_short_addr(__le16 addr)
  {
  	/* First bit of addr is multicast, reserved or 802.15.4 specific */
  	return !(addr & cpu_to_le16(0x8000));
  }

  static inline void lowpan_push_hc_data(u8 **hc_ptr, const void *data,
  				       const size_t len)
  {
  	memcpy(*hc_ptr, data, len);
  	*hc_ptr += len;
  }

  int lowpan_register_netdevice(struct net_device *dev,
  			      enum lowpan_lltypes lltype);
  int lowpan_register_netdev(struct net_device *dev,
  			   enum lowpan_lltypes lltype);
  void lowpan_unregister_netdevice(struct net_device *dev);
  void lowpan_unregister_netdev(struct net_device *dev);

  /**
   * lowpan_header_decompress - replace 6LoWPAN header with IPv6 header
   *
   * This function replaces the IPHC 6LoWPAN header which should be pointed at
   * skb->data and skb_network_header, with the IPv6 header.
   * It would be nice that the caller have the necessary headroom of IPv6 header
   * and greatest Transport layer header, this would reduce the overhead for
   * reallocate headroom.
   *
   * @skb: the buffer which should be manipulate.
   * @dev: the lowpan net device pointer.
   * @daddr: destination lladdr of mac header which is used for compression
   *	methods.
   * @saddr: source lladdr of mac header which is used for compression
   *	methods.
   */
  int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
  			     const void *daddr, const void *saddr);

  
  /**
   * lowpan_header_compress - replace IPv6 header with 6LoWPAN header
   *
   * This function replaces the IPv6 header which should be pointed at
   * skb->data and skb_network_header, with the IPHC 6LoWPAN header.
   * The caller need to be sure that the sk buffer is not shared and at have
   * at least a headroom which is smaller or equal LOWPAN_IPHC_MAX_HEADER_LEN,
   * which is the IPHC "more bytes than IPv6 header" at worst case.
   *
   * @skb: the buffer which should be manipulate.
   * @dev: the lowpan net device pointer.
   * @daddr: destination lladdr of mac header which is used for compression
   *	methods.
   * @saddr: source lladdr of mac header which is used for compression
   *	methods.
   */
  int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
  			   const void *daddr, const void *saddr);

  #endif /* __6LOWPAN_H__ */