zsm/include/packet.h

#ifndef PACKET_H
#define PACKET_H

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#include <fcntl.h>
#include <pthread.h>
#include <sodium.h>
#include <libgen.h>
#include <wchar.h>

#include "config.h"

#define ERROR_LENGTH 26

#define ZSM_TYP_AUTH 0x1
#define ZSM_TYP_MESSAGE 0x2
#define ZSM_TYP_UPDATE_MESSAGE 0x3
#define ZSM_TYP_DELETE_MESSAGE 0x4
#define ZSM_TYP_ERROR 0x5
#define ZSM_TYP_INFO 0x6

#define ZSM_STA_SUCCESS 0x1
#define ZSM_STA_INVALID_TYPE 0x2
#define ZSM_STA_INVALID_LENGTH 0x3
#define ZSM_STA_TOO_LONG 0x4
#define ZSM_STA_READING_SOCKET 0x5
#define ZSM_STA_WRITING_SOCKET 0x6
#define ZSM_STA_UNKNOWN_USER 0x7
#define ZSM_STA_MEMORY_ALLOCATION 0x8
#define ZSM_STA_ERROR_ENCRYPT 0x9
#define ZSM_STA_ERROR_DECRYPT 0xA
#define ZSM_STA_ERROR_AUTHENTICATE 0xB
#define ZSM_STA_ERROR_INTEGRITY 0xC
#define ZSM_STA_UNAUTHORISED 0xD
#define ZSM_STA_AUTHORISED 0xE

#define ADDRESS_SIZE MAX_NAME + 1 + 255 /* 1 for @, 255 for domain, defined in RFC 5321, Section 4.5.3.1.2 */
#define CHALLENGE_SIZE 32
#define HASH_SIZE crypto_generichash_BYTES
#define NONCE_SIZE crypto_aead_xchacha20poly1305_ietf_NPUBBYTES
#define ADDITIONAL_SIZE crypto_aead_xchacha20poly1305_ietf_ABYTES

typedef struct packet {
    uint8_t status;
    uint8_t type;
    uint32_t length;
    uint8_t *data;
    uint8_t *signature;
} packet;

#include "key.h"

/* Utilities functions */
void print_packet(packet *msg);
int recv_packet(packet *pkt, int fd, uint8_t required_type);
packet *create_packet(uint8_t option, uint8_t type, uint32_t length, uint8_t *data, uint8_t *signature);
int send_packet(packet *msg, int fd);
void free_packet(packet *msg);
int encrypt_packet(int sockfd, key_pair *kp);
packet *verify_packet(packet *pkt, int fd);
uint8_t *encrypt_data(uint8_t *from, uint8_t *to, uint8_t *raw, uint32_t raw_length, uint32_t *length);
uint8_t *decrypt_data(packet *pkt);
int verify_integrity(packet *pkt, public_key *pk);
uint8_t *create_signature(uint8_t *data, uint32_t length, secret_key *sk);

#endif