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/** \file
* \brief The utility functions for the internet protocol.
* \note The header includes functions which are required when using raw TCP/IP
* sockets.
*/
/*
* Copyright (c) 2019-2021 David Timber <mieabby@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#pragma once
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include "protocol.h"
/* Alias declarations */
typedef struct prne_iphdr4 prne_iphdr4_t;
typedef struct prne_iphdr6 prne_iphdr6_t;
/** \struct prne_iphdr4 \struct prne_iphdr6
* \brief The workaround for the issues in uClibc headers.
* \note At the time of writing the code, the IPv6 support of uClibc was not
* complete and there were some problems using the IP headers provided by
* uClibc. These structures are exactly the same as the counterparts in the
* standard IP headers.
* \note The values must be in the host byte order. Unlike the standard
* functions, the serialisation and deserialisation functions are responsible
* for byte order conversion.
*/
struct prne_iphdr4 {
uint8_t saddr[4];
uint8_t daddr[4];
uint16_t total_len;
uint16_t id;
uint8_t ttl;
uint8_t protocol;
uint8_t ihl;
};
struct prne_iphdr6 {
uint8_t saddr[16];
uint8_t daddr[16];
uint32_t flow_label;
uint16_t payload_len;
uint8_t next_hdr;
uint8_t hop_limit;
};
/**
* \brief Set bits to represent the CIDR
* \param out The byte array used to represent the netmask.
* \param cidr The CIDR value.
* \note The number of elements modified is calculated by dividing \p cidr by 8.
* For example, if the \p cidr is passed as 24, only the first 3 elements of
* \p out are modified to set the first 24 bits.
* \warning The behaviour is undefined if \p cidr divided by 8 is larger than
* the size of \p out (buffer overflow).
*/
void prne_netmask_from_cidr (uint8_t *out, size_t cidr);
/**
* \brief Calculate the checksum of the IPv4 TCP packet.
* \param ih The pointer to the IPv4 header structure.
* \param th The pointer to the TCP header data.
* \param th_len The byte length of the TCP header data.
* \param data The pointer to the payload data.
* \param data_len The byte length of the payload data.
* \return The calculated checksum value in the host byte order. The value must
* be converted to the network byte order.
*/
uint16_t prne_calc_tcp_chksum4 (
const prne_iphdr4_t *ih,
const uint8_t *th,
size_t th_len,
const uint8_t *data,
size_t data_len);
/**
* \brief Calculate the checksum of the IPv6 TCP packet.
* \param ih The pointer to the IPv6 header structure.
* \param th The pointer to the TCP header data.
* \param th_len The byte length of the TCP header data.
* \param data The pointer to the payload data.
* \param data_len The byte length of the payload data.
* \return The calculated checksum value in the host byte order. The value must
* be converted to the network byte order.
* \note The same algorithm(the function) can be used to calculate the checksum
* values of ICMP packets.
*/
uint16_t prne_calc_tcp_chksum6 (
const prne_iphdr6_t *ih,
const uint8_t *th,
size_t th_len,
const uint8_t *data,
size_t data_len);
/**
* \brief Serialise the IPv4 header structure for transmission.
* \param mem The destination buffer. The length of the buffer must be at least
* 20 bytes.
* \param in The pointer to the IPv4 header structure.
*/
void prne_ser_iphdr4 (uint8_t *mem, const prne_iphdr4_t *in);
/**
* \brief Serialise the IPv6 header structure for transmission.
* \param mem The destination buffer. The length of the buffer must be at least
* 40 bytes.
* \param in The pointer to the IPv6 header structure.
*/
void prne_ser_iphdr6 (uint8_t *mem, const prne_iphdr6_t *in);
/**
* \brief Deserialise the IPv4 header from the binary data.
* \param data The binary data. The length must be at least 20 bytes.
* \param out The pointer to the IPv4 header structure.
*/
void prne_dser_iphdr4 (const uint8_t *data, prne_iphdr4_t *out);
/**
* \brief Deserialise the IPv6 header from the binary data.
* \param data The binary data. The length must be at least 40 bytes.
* \param out The pointer to the IPv6 header structure.
*/
void prne_dser_iphdr6 (const uint8_t *data, prne_iphdr6_t *out);
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