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/*
* Copyright (C) 2015 José Ignacio Alamos <jialamos@uc.cl>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup net_ipv4_hdr IPv4 header
* @ingroup net_ipv4
* @brief IPv4 header types and helper functions
* @{
*
* @file
* @brief IPv4 header type and helper function definitions
*
* @author José Ignacio Alamos <jialamos@uc.cl>
*/
#ifndef IPV4_HDR_H
#define IPV4_HDR_H
#include "byteorder.h"
#include "net/ipv4/addr.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Data type to represent an IPv4 packet header.
*
* @details The structure of the header is as follows:
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ {.unparsed}
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |Version| IHL |Type of Service| Total Length |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Identification |Flags| Fragment Offset |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Time to Live | Protocol | Header Checksum |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Source Address |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Destination Address |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Options | Padding |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* @see <a href="https://tools.ietf.org/html/rfc791#section-3.1">
* RFC 791, section 3.1
* </a>
*/
typedef struct __attribute__((packed)) {
/**
* @brief Version and Internet Header Length.
*
* @details The version are the 4 most significant bits and the Internet Header Length
* the 4 next bit (see above).
*
* This module provides helper functions to set, get, and check these
* fields accordingly:
* * ipv4_hdr_set_version()
* * ipv4_hdr_get_version()
* * ipv4_hdr_set_ihl()
* * ipv4_hdr_get_ihl()
*/
uint8_t v_ih;
uint8_t ts; /**< type of service of packet*/
network_uint16_t tl; /**< total length of the datagram */
network_uint16_t id; /**< identification value of packet */
/**
* @brief version control flags and Fragment Offset.
*
* @details The flags are the 3 most significant bits, and the remaining 13 bits are the fragment offfset
*
* This module provides helper functions to set, get, and check these
* fields accordingly:
* * ipv4_hdr_set_flags()
* * ipv4_hdr_get_flags()
* * ipv4_hdr_set_fo()
* * ipv4_hdr_get_fo()
*/
network_uint16_t fl_fo;
uint8_t ttl; /**< time to live for this packet */
uint8_t protocol; /**< protocol of this packet */
network_uint16_t csum; /**< checksum of this packet */
ipv4_addr_t src; /**< source address of this packet */
ipv4_addr_t dst; /**< destination address of this packet */
} ipv4_hdr_t;
/**
* @brief Sets the version field of @p hdr to 6
*
* @param[out] hdr Pointer to an IPv4 header.
*/
static inline void ipv4_hdr_set_version(ipv4_hdr_t *hdr)
{
hdr->v_ih &= 0x0f;
hdr->v_ih |= 0x40;
}
/**
* @brief Gets the value of the version field of @p hdr
*
* @param[in] hdr Pointer to an IPv4 header.
*
* @return Value of the version field of @p hdr.
*/
static inline uint8_t ipv4_hdr_get_version(ipv4_hdr_t *hdr)
{
return ((hdr->v_ih) >> 4);
}
/**
* @brief Sets the Internet Header Length field of @p hdr
*
* @param[out] hdr Pointer to an IPv4 header.
* @param[in] ihl Size in bytes of the Internet Header Length (including padding)
*/
static inline void ipv4_hdr_set_ihl(ipv4_hdr_t *hdr, uint16_t ihl)
{
hdr->v_ih &= 0xf0;
hdr->v_ih |= 0x0f & (ihl >> 5);
}
/**
* brief Gets the value of the Internet Header Length field of @p hdr
*
* @param[in] hdr Pointer to an IPv4 header.
*
* @return Size in bytes of the Internet Header Length field of @p hdr
*/
static inline uint16_t ipv4_hdr_get_ihl(ipv4_hdr_t *hdr)
{
return (hdr->v_ih & 0x0f) << 5;
}
/**
* @brief Sets the Version Control Flags field of @p hdr
*
* @param[out] hdr Pointer to an IPv4 header.
* @param[in] flags The new value of flags
*/
static inline void ipv4_hdr_set_flags(ipv4_hdr_t *hdr, uint8_t flags)
{
hdr->fl_fo.u8[0] &= 0x1f;
hdr->fl_fo.u8[0] |= (0xe0 & (flags << 5));
}
/**
* brief Gets the value of the Version Control Flags field of @p hdr
*
* @param[in] hdr Pointer to an IPv4 header.
*
* @return Value of the Version Control field of @p hdr
*/
static inline uint8_t ipv4_hdr_get_flags(ipv4_hdr_t *hdr)
{
return (((hdr->fl_fo.u8[0]) >> 5) & 0x07);
}
/**
* @brief Sets the Fragment Offset field of @p hdr
*
* @param[out] hdr Pointer to an IPv4 header.
* @param[in] fo The new value of fragment offset
*/
static inline void ipv4_hdr_set_fo(ipv4_hdr_t *hdr, uint16_t fo)
{
hdr->fl_fo.u8[0] &= 0xe0;
hdr->fl_fo.u8[0] |= (0x1f & (fo >> 8));
hdr->fl_fo.u8[1] = 0xff & fo;
}
/**
* brief Gets the value of the Fragment Offset field of @p hdr
*
* @param[in] hdr Pointer to an IPv4 header.
*
* @return Value of the Fragment Offset field of @p hdr
*/
static inline uint16_t ipv4_hdr_get_fo(ipv4_hdr_t *hdr)
{
return (((hdr->fl_fo.u8[0] & 0x1f) << 8) + hdr->fl_fo.u8[1]);
}
#ifdef __cplusplus
}
#endif
#endif /* IPV4_HDR_H */
/** @} */
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