/*
* Copyright (c) 2009 Lukas Mejdrech
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup ip
* @{
*/
/** @file
* IP header and options definitions.
* Based on the RFC~791.
*/
#ifndef __NET_IP_HEADER_H__
#define __NET_IP_HEADER_H__
#include <byteorder.h>
#include <sys/types.h>
/** Returns the actual IP header length in bytes.
* @param[in] header The IP packet header.
*/
#define IP_HEADER_LENGTH( header ) (( header )->header_length * 4u )
/** Returns the IP header length.
* @param[in] length The IP header length in bytes.
*/
#define IP_COMPUTE_HEADER_LENGTH( length ) (( uint8_t ) (( length ) / 4u ))
/** Returns the actual IP packet total length.
* @param[in] header The IP packet header.
*/
#define IP_TOTAL_LENGTH( header ) ntohs(( header )->total_length )
/** Returns the actual IP packet data length.
* @param[in] header The IP packet header.
*/
#define IP_HEADER_DATA_LENGTH( header ) ( IP_TOTAL_LENGTH( header ) - IP_HEADER_LENGTH( header ))
/** Returns the IP packet header checksum.
* @param[in] header The IP packet header.
*/
#define IP_HEADER_CHECKSUM( header ) ( htons( ip_checksum(( uint8_t * )( header ), IP_HEADER_LENGTH( header ))))
/** Returns the fragment offest.
* @param[in] header The IP packet header.
*/
#define IP_FRAGMENT_OFFSET( header ) (((( header )->fragment_offset_high << 8 ) + ( header )->fragment_offset_low ) * 8u )
/** Returns the fragment offest high bits.
* @param[in] length The prefixed data total length.
*/
#define IP_COMPUTE_FRAGMENT_OFFSET_HIGH( length ) (((( length ) / 8u ) & 0x1F00 ) >> 8 )
/** Returns the fragment offest low bits.
* @param[in] length The prefixed data total length.
*/
#define IP_COMPUTE_FRAGMENT_OFFSET_LOW( length ) ((( length ) / 8u ) & 0xFF )
/** Type definition of the internet header.
* @see ip_header
*/
typedef struct ip_header ip_header_t;
/** Type definition of the internet header pointer.
* @see ip_header
*/
typedef ip_header_t * ip_header_ref;
/** Internet header.
* The variable options should be included after the header itself and indicated by the increased header length value.
*/
struct ip_header{
#ifdef ARCH_IS_BIG_ENDIAN
/** The Version field indicates the format of the internet header.
*/
uint8_t version:4;
/** Internet Header Length is the length of the internet header in 32~bit words, and thus points to the beginning of the data.
* Note that the minimum value for a~correct header is~5.
*/
uint8_t header_length:4;
#else
/** Internet Header Length is the length of the internet header in 32~bit words, and thus points to the beginning of the data.
* Note that the minimum value for a~correct header is~5.
*/
uint8_t header_length:4;
/** The Version field indicates the format of the internet header.
*/
uint8_t version:4;
#endif
/** The Type of Service provides an indication of the abstract parameters of the quality of service desired.
* These parameters are to be used to guide the selection of the actual service parameters when transmitting a~datagram through a~particular network.
* Several networks offer service precedence, which somehow treats high precedence traffic as more important than other traffic (generally by accepting only traffic above a~certain precedence at time of high load).
* The major choice is a~three way tradeoff between low-delay, high-reliability, and high-throughput.
*/
uint8_t tos;
/** Total Length is the length of the datagram, measured in octets, including internet header and data.
* This field allows the length of a~datagram to be up to 65,535~octets.
*/
uint16_t total_length;
/** An identifying value assigned by the sender to aid in assembling the fragments of a~datagram.
*/
uint16_t identification;
#ifdef ARCH_IS_BIG_ENDIAN
/** Various control flags.
*/
uint8_t flags:3;
/** This field indicates where in the datagram this fragment belongs.
* High bits.
*/
uint8_t fragment_offset_high:5;
#else
/** This field indicates where in the datagram this fragment belongs.
* High bits.
*/
uint8_t fragment_offset_high:5;
/** Various control flags.
*/
uint8_t flags:3;
#endif
/** This field indicates where in the datagram this fragment belongs.
* Low bits.
*/
uint8_t fragment_offset_low;
/** This field indicates the maximum time the datagram is allowed to remain in the internet system.
* If this field contains the value zero, then the datagram must be destroyed.
* This field is modified in internet header processing.
* The time is measured in units of seconds, but since every module that processes a~datagram must decrease the TTL by at least one even if it process the datagram in less than a~second, the TTL must be thought of only as an upper bound on the time a~datagram may exist.
* The intention is to cause undeliverable datagrams to be discarded, and to bound the maximum datagram lifetime.
*/
uint8_t ttl;
/** This field indicates the next level protocol used in the data portion of the internet datagram.
*/
uint8_t protocol;
/** A checksum of the header only.
* Since some header fields change (e.g., time to live), this is recomputed and verified at each point that the internet header is processed.
* The checksum algorithm is: The checksum field is the 16~bit one's complement of the one's complement sum of all 16~bit words in the header.
* For purposes of computing the checksum, the value of the checksum field is zero.
*/
uint16_t header_checksum;
/** The source address.
*/
uint32_t source_address;
/** The destination address.
*/
uint32_t destination_address;
} __attribute__ ((packed));
/** Type definition of the internet option header.
* @see ip_header
*/
typedef struct ip_option ip_option_t;
/** Type definition of the internet option header pointer.
* @see ip_header
*/
typedef ip_option_t * ip_option_ref;
/** Internet option header.
* Only type field is always valid.
* Other fields' validity depends on the option type.
*/
struct ip_option{
/** A single octet of option-type.
*/
uint8_t type;
/** An option length octet.
*/
uint8_t length;
/** A~pointer.
*/
uint8_t pointer;
#ifdef ARCH_IS_BIG_ENDIAN
/** The number of IP modules that cannot register timestamps due to lack of space.
*/
uint8_t overflow:4;
/** Various internet timestamp control flags.
*/
uint8_t flags:4;
#else
/** Various internet timestamp control flags.
*/
uint8_t flags:4;
/** The number of IP modules that cannot register timestamps due to lack of space.
*/
uint8_t overflow:4;
#endif
} __attribute__ ((packed));
/** @name IP flags definitions
*/
/*@{*/
/** Fragment flag field shift.
*/
#define IPFLAG_FRAGMENT_SHIFT 1
/** Fragmented flag field shift.
*/
#define IPFLAG_FRAGMENTED_SHIFT 0
/** May fragment flag value.
* Allows the packet fragmentation.
*/
#define IPFLAG_MAY_FRAGMENT ( 0x0 << IPFLAG_FRAGMENT_SHIFT )
/** Don't fragment flag value.
* Permits the packet fragmentation.
*/
#define IPFLAG_DONT_FRAGMENT ( 0x1 << IPFLAG_FRAGMENT_SHIFT )
/** Last fragment flag value.
* Indicates the last packet fragment.
*/
#define IPFLAG_LAST_FRAGMENT ( 0x0 << IPFLAG_FRAGMENTED_SHIFT )
/** More fragments flag value.
* Indicates that more packet fragments follow.
*/
#define IPFLAG_MORE_FRAGMENTS ( 0x1 << IPFLAG_FRAGMENTED_SHIFT )
/*@}*/
/** Type definition of the internet version 4 pseudo header.
* @see ipv4_pseudo_header
*/
typedef struct ipv4_pseudo_header ipv4_pseudo_header_t;
/** Type definition of the internet version 4 pseudo header pointer.
* @see ipv4_pseudo_header
*/
typedef ipv4_pseudo_header_t * ipv4_pseudo_header_ref;
/** Internet version 4 pseudo header.
*/
struct ipv4_pseudo_header{
/** The source address.
*/
uint32_t source_address;
/** The destination address.
*/
uint32_t destination_address;
/** Reserved byte.
* Must be zero.
*/
uint8_t reserved;
/** This field indicates the next level protocol used in the data portion of the internet datagram.
*/
uint8_t protocol;
/** Data length is the length of the datagram, measured in octets.
*/
uint16_t data_length;
} __attribute__ ((packed));
#endif
/** @}
*/