text: /*
   * 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 <net/ipv6.h>
  #include <net/net_namespace.h>
  
  #define UIP_802154_SHORTADDR_LEN	2  /* compressed ipv6 address length */
  #define UIP_IPH_LEN			40 /* ipv6 fixed header size */
  #define UIP_PROTO_UDP			17 /* ipv6 next header value for UDP */
  #define UIP_FRAGH_LEN			8  /* ipv6 fragment header size */
  
  /*
   * ipv6 address based on mac
   * second bit-flip (Universe/Local) is done according RFC2464
   */
  #define is_addr_mac_addr_based(a, m) \
  	((((a)->s6_addr[8])  == (((m)[0]) ^ 0x02)) &&	\
  	 (((a)->s6_addr[9])  == (m)[1]) &&		\
  	 (((a)->s6_addr[10]) == (m)[2]) &&		\
  	 (((a)->s6_addr[11]) == (m)[3]) &&		\
  	 (((a)->s6_addr[12]) == (m)[4]) &&		\
  	 (((a)->s6_addr[13]) == (m)[5]) &&		\
  	 (((a)->s6_addr[14]) == (m)[6]) &&		\
  	 (((a)->s6_addr[15]) == (m)[7]))
  
  /*
   * check whether we can compress the IID to 16 bits,
   * it's possible for unicast adresses with first 49 bits are zero only.
   */
  #define lowpan_is_iid_16_bit_compressable(a)	\
  	((((a)->s6_addr16[4]) == 0) &&		\
  	 (((a)->s6_addr[10]) == 0) &&		\
  	 (((a)->s6_addr[11]) == 0xff) &&	\
  	 (((a)->s6_addr[12]) == 0xfe) &&	\
  	 (((a)->s6_addr[13]) == 0))
  
  /* check whether the 112-bit gid of the multicast address is mappable to: */
  
  /* 48 bits, FFXX::00XX:XXXX:XXXX */
  #define lowpan_is_mcast_addr_compressable48(a)	\
  	((((a)->s6_addr16[1]) == 0) &&		\
  	 (((a)->s6_addr16[2]) == 0) &&		\
  	 (((a)->s6_addr16[3]) == 0) &&		\
  	 (((a)->s6_addr16[4]) == 0) &&		\
  	 (((a)->s6_addr[10]) == 0))
  
  /* 32 bits, FFXX::00XX:XXXX */
  #define lowpan_is_mcast_addr_compressable32(a)	\
  	((((a)->s6_addr16[1]) == 0) &&		\
  	 (((a)->s6_addr16[2]) == 0) &&		\
  	 (((a)->s6_addr16[3]) == 0) &&		\
  	 (((a)->s6_addr16[4]) == 0) &&		\
  	 (((a)->s6_addr16[5]) == 0) &&		\
  	 (((a)->s6_addr[12]) == 0))
  
  /* 8 bits, FF02::00XX */
  #define lowpan_is_mcast_addr_compressable8(a)	\
  	((((a)->s6_addr[1])  == 2) &&		\
  	 (((a)->s6_addr16[1]) == 0) &&		\
  	 (((a)->s6_addr16[2]) == 0) &&		\
  	 (((a)->s6_addr16[3]) == 0) &&		\
  	 (((a)->s6_addr16[4]) == 0) &&		\
  	 (((a)->s6_addr16[5]) == 0) &&		\
  	 (((a)->s6_addr16[6]) == 0) &&		\
  	 (((a)->s6_addr[14]) == 0))
  
  #define lowpan_is_addr_broadcast(a)	\
  	((((a)[0]) == 0xFF) &&	\
  	 (((a)[1]) == 0xFF) &&	\
  	 (((a)[2]) == 0xFF) &&	\
  	 (((a)[3]) == 0xFF) &&	\
  	 (((a)[4]) == 0xFF) &&	\
  	 (((a)[5]) == 0xFF) &&	\
  	 (((a)[6]) == 0xFF) &&	\
  	 (((a)[7]) == 0xFF))
  
  #define LOWPAN_DISPATCH_IPV6	0x41 /* 01000001 = 65 */
  #define LOWPAN_DISPATCH_HC1	0x42 /* 01000010 = 66 */
  #define LOWPAN_DISPATCH_IPHC	0x60 /* 011xxxxx = ... */
  #define LOWPAN_DISPATCH_FRAG1	0xc0 /* 11000xxx */
  #define LOWPAN_DISPATCH_FRAGN	0xe0 /* 11100xxx */
  
  #define LOWPAN_DISPATCH_MASK	0xf8 /* 11111000 */
  
  #define LOWPAN_FRAG_TIMEOUT	(HZ * 60)	/* time-out 60 sec */
  
  #define LOWPAN_FRAG1_HEAD_SIZE	0x4
  #define LOWPAN_FRAGN_HEAD_SIZE	0x5
  
  /*
   * Values of fields within the IPHC encoding first byte
   * (C stands for compressed and I for inline)
   */
  #define LOWPAN_IPHC_TF		0x18
  
  #define LOWPAN_IPHC_FL_C	0x10
  #define LOWPAN_IPHC_TC_C	0x08
  #define LOWPAN_IPHC_NH_C	0x04
  #define LOWPAN_IPHC_TTL_1	0x01
  #define LOWPAN_IPHC_TTL_64	0x02
  #define LOWPAN_IPHC_TTL_255	0x03
  #define LOWPAN_IPHC_TTL_I	0x00
  
  
  /* Values of fields within the IPHC encoding second byte */
  #define LOWPAN_IPHC_CID		0x80
  
  #define LOWPAN_IPHC_ADDR_00	0x00
  #define LOWPAN_IPHC_ADDR_01	0x01
  #define LOWPAN_IPHC_ADDR_02	0x02
  #define LOWPAN_IPHC_ADDR_03	0x03
  
  #define LOWPAN_IPHC_SAC		0x40
  #define LOWPAN_IPHC_SAM		0x30
  
  #define LOWPAN_IPHC_SAM_BIT	4
  
  #define LOWPAN_IPHC_M		0x08
  #define LOWPAN_IPHC_DAC		0x04
  #define LOWPAN_IPHC_DAM_00	0x00
  #define LOWPAN_IPHC_DAM_01	0x01
  #define LOWPAN_IPHC_DAM_10	0x02
  #define LOWPAN_IPHC_DAM_11	0x03
  
  #define LOWPAN_IPHC_DAM_BIT	0
  /*
   * LOWPAN_UDP encoding (works together with IPHC)
   */
  #define LOWPAN_NHC_UDP_MASK		0xF8
  #define LOWPAN_NHC_UDP_ID		0xF0
  #define LOWPAN_NHC_UDP_CHECKSUMC	0x04
  #define LOWPAN_NHC_UDP_CHECKSUMI	0x00
  
  #define LOWPAN_NHC_UDP_4BIT_PORT	0xF0B0
  #define LOWPAN_NHC_UDP_4BIT_MASK	0xFFF0
  #define LOWPAN_NHC_UDP_8BIT_PORT	0xF000
  #define LOWPAN_NHC_UDP_8BIT_MASK	0xFF00
  
  /* values for port compression, _with checksum_ ie bit 5 set to 0 */
  #define LOWPAN_NHC_UDP_CS_P_00	0xF0 /* all inline */
  #define LOWPAN_NHC_UDP_CS_P_01	0xF1 /* source 16bit inline,
  					dest = 0xF0 + 8 bit inline */
  #define LOWPAN_NHC_UDP_CS_P_10	0xF2 /* source = 0xF0 + 8bit inline,
  					dest = 16 bit inline */
  #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
  #define LOWPAN_NHC_UDP_CS_C	0x04 /* checksum elided */
  
  #ifdef DEBUG
  /* print data in line */
  static inline void raw_dump_inline(const char *caller, char *msg,
  				   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,
  				  unsigned char *buf, int len)
  {
  	if (msg)
  		pr_debug("%s():%s:\n", 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,
  				  unsigned char *buf, int len) { }
  static inline void raw_dump_inline(const char *caller, char *msg,
  				   unsigned char *buf, int len) { }
  #endif
  
  static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)
  {
  	if (unlikely(!pskb_may_pull(skb, 1)))
  		return -EINVAL;
  
  	*val = skb->data[0];
  	skb_pull(skb, 1);
  
  	return 0;
  }
  
  static inline bool lowpan_fetch_skb(struct sk_buff *skb,
  		void *data, const 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 void lowpan_push_hc_data(u8 **hc_ptr, const void *data,
  				       const size_t len)
  {
  	memcpy(*hc_ptr, data, len);
  	*hc_ptr += len;
  }
  
  static inline u8 lowpan_addr_mode_size(const u8 addr_mode)
  {
  	static const u8 addr_sizes[] = {
  		[LOWPAN_IPHC_ADDR_00] = 16,
  		[LOWPAN_IPHC_ADDR_01] = 8,
  		[LOWPAN_IPHC_ADDR_02] = 2,
  		[LOWPAN_IPHC_ADDR_03] = 0,
  	};
  	return addr_sizes[addr_mode];
  }
  
  static inline u8 lowpan_next_hdr_size(const u8 h_enc, u16 *uncomp_header)
  {
  	u8 ret = 1;
  
  	if ((h_enc & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
  		*uncomp_header += sizeof(struct udphdr);
  
  		switch (h_enc & LOWPAN_NHC_UDP_CS_P_11) {
  		case LOWPAN_NHC_UDP_CS_P_00:
  			ret += 4;
  			break;
  		case LOWPAN_NHC_UDP_CS_P_01:
  		case LOWPAN_NHC_UDP_CS_P_10:
  			ret += 3;
  			break;
  		case LOWPAN_NHC_UDP_CS_P_11:
  			ret++;
  			break;
  		default:
  			break;
  		}
  
  		if (!(h_enc & LOWPAN_NHC_UDP_CS_C))
  			ret += 2;
  	}
  
  	return ret;
  }
  
  /**
   *	lowpan_uncompress_size - returns skb->len size with uncompressed header
   *	@skb: sk_buff with 6lowpan header inside
   *	@datagram_offset: optional to get the datagram_offset value
   *
   *	Returns the skb->len with uncompressed header
   */
  static inline u16
  lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
  {
  	u16 ret = 2, uncomp_header = sizeof(struct ipv6hdr);
  	u8 iphc0, iphc1, h_enc;
  
  	iphc0 = skb_network_header(skb)[0];
  	iphc1 = skb_network_header(skb)[1];
  
  	switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
  	case 0:
  		ret += 4;
  		break;
  	case 1:
  		ret += 3;
  		break;
  	case 2:
  		ret++;
  		break;
  	default:
  		break;
  	}
  
  	if (!(iphc0 & LOWPAN_IPHC_NH_C))
  		ret++;
  
  	if (!(iphc0 & 0x03))
  		ret++;
  
  	ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_SAM) >>
  				     LOWPAN_IPHC_SAM_BIT);
  
  	if (iphc1 & LOWPAN_IPHC_M) {
  		switch ((iphc1 & LOWPAN_IPHC_DAM_11) >>
  			LOWPAN_IPHC_DAM_BIT) {
  		case LOWPAN_IPHC_DAM_00:
  			ret += 16;
  			break;
  		case LOWPAN_IPHC_DAM_01:
  			ret += 6;
  			break;
  		case LOWPAN_IPHC_DAM_10:
  			ret += 4;
  			break;
  		case LOWPAN_IPHC_DAM_11:
  			ret++;
  			break;
  		default:
  			break;
  		}
  	} else {
  		ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_DAM_11) >>
  					     LOWPAN_IPHC_DAM_BIT);
  	}
  
  	if (iphc0 & LOWPAN_IPHC_NH_C) {
  		h_enc = skb_network_header(skb)[ret];
  		ret += lowpan_next_hdr_size(h_enc, &uncomp_header);
  	}
  
  	if (dgram_offset)
  		*dgram_offset = uncomp_header;
  
  	return skb->len + uncomp_header - ret;
  }
  
  typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
  
  int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
  		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
  		const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
  		u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
  int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
  			unsigned short type, const void *_daddr,
  			const void *_saddr, unsigned int len);
  
  #endif /* __6LOWPAN_H__ */
  