libmp/include/mptp.h

#pragma once
#include <netdb.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>

// clang-format off

/*

 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 #####################################
 #                FLAGS              #
 #####################################
 #    HOST SIZE    |    PATH SIZE    #
 #####################################
 #             DATA SIZE             #
 #####################################
 #                HOST               #
 #                PATH               #
 #                DATA               #
 #...................................#

 [16 bits] FLAGS
 =========================================================
 | 8 bits used for specifying the version
 ---------------------------------------------------------
 | 1 bit used to specify if this is a request or response
 |
 | 0- it's a request
 | 1- it's a response
 ---------------------------------------------------------
 | 4 bits used for request/response codes
 |
 | We have 4 types of different requests
 | 0- PING: checks if the server is avaliable
 | 1- INFO: gets information about the pool(s) the server is hosting
 | 2- LIST: requests the package list for certain pool
 | 3- PULL: requests a certain package from a certain pool
 |
 | And 4 types of responses
 | 0- PONG: response for the ping request
 | 1- COOL: everything is fine, here's the data you requested
 | 2- BRUH: cannot access to the data you requested, or version mismatch
 | 3- WHAT: bad request
 ---------------------------------------------------------
 | 1 bit used to specify if this the last response
 |
 | 0- no stay connected, im not done responsing yet
 | 1- yes, im done, disconnect
 |
 | always 1 for the requests
 ---------------------------------------------------------
 | 2 bits is reserved for future use
 ---------------------------------------------------------


 [8 bits] HOST SIZE
 =========================================================
 | All bits used for specifying HOST size, always zero
 | for responses
 ---------------------------------------------------------

 [8 bits] DATA SIZE
 =========================================================
 | 8 bits used for specifying DATA size
 ---------------------------------------------------------

 [...] HOST
 ---------------------------------------------------------
 | Plaintext server hostname, max size is 255 octets
 | see the SIZE section, always empty for responses
 ---------------------------------------------------------

 [...] DATA
 ---------------------------------------------------------
 | Plaintext data used for that specific request/response,
 | max size is 255 octets, see the SIZE section
 ---------------------------------------------------------

*/

// clang-format on

#define MPTP_VERSION_SUPPORTED 0
#define MPTP_CODE_MAX          3
#define MPTP_DATA_MAX          4096 // generally this is the page size on x86_64 linux
#define MPTP_PATH_MAX          UINT8_MAX
#define MPTP_HOST_MAX          UINT8_MAX
#define MPTP_TIMEOUT           10

#define MPTP_REQUEST  0
#define MPTP_RESPONSE 1

typedef enum lm_mptp_request {
  MPTP_C2S_PING = 0,
  MPTP_C2S_INFO = 1,
  MPTP_C2S_LIST = 2,
  MPTP_C2S_PULL = 3,
} lm_mptp_request_t;

typedef enum lm_mptp_response {
  MPTP_S2C_PONG = 0,
  MPTP_S2C_COOL = 1,
  MPTP_S2C_BRUH = 2,
  MPTP_S2C_WHAT = 3,
} lm_mptp_response_t;

typedef struct lm_mptp_header {
  uint16_t flags;
  uint8_t  host_size;
  uint8_t  path_size;
  uint16_t data_size;
} __attribute__((packed)) lm_mptp_header_t;

typedef struct lm_mptp {
  lm_mptp_header_t header;
  char            *host, *path, *data;
} lm_mptp_t;

typedef bool (*lm_mptp_transfer_callback_t)(char *path, size_t current, size_t total, void *data);

#define MPTP_FLAGS_VERSION(m) (((m)->header.flags >> 8) & 0xFF)
#define MPTP_FLAGS_TYPE(m)    (((m)->header.flags >> 7) & 0x01)
#define MPTP_FLAGS_CODE(m)    (((m)->header.flags >> 3) & 0x0F)
#define MPTP_FLAGS_LAST(m)    (((m)->header.flags >> 2) & 0x01)

#define MPTP_IS_REQUEST(m) (MPTP_FLAGS_TYPE(m) == 0)
#define MPTP_IS_LAST(m)    (MPTP_FLAGS_LAST(m) == 1)

void lm_mptp_init(lm_mptp_t *packet);
bool lm_mptp_new(lm_mptp_t *packet, bool is_request, uint8_t code, bool is_last);
void lm_mptp_free(lm_mptp_t *packet);

int  lm_mptp_socket(char *addr, uint16_t port, struct sockaddr *saddr);
bool lm_mptp_socket_opts(int sock);
void lm_mptp_copy(lm_mptp_t *dst, lm_mptp_t *src);
bool lm_mptp_verify(lm_mptp_t *packet);
void lm_mptp_close(int sock);
bool lm_mptp_recv(int sock, lm_mptp_t *packet);
void lm_mptp_free(lm_mptp_t *packet);

bool lm_mptp_set_data(lm_mptp_t *packet, char *data, size_t size);
bool lm_mptp_get_data(lm_mptp_t *packet, char *data);

bool lm_mptp_set_host(lm_mptp_t *packet, char *host);
bool lm_mptp_get_host(lm_mptp_t *packet, char *host);

bool lm_mptp_set_path(lm_mptp_t *packet, char *path);
bool lm_mptp_get_path(lm_mptp_t *packet, char *path);

int  lm_mptp_client_connect(char *addr, uint16_t port);
bool lm_mptp_client_verify(lm_mptp_t *packet);
bool lm_mptp_client_send(int sock, lm_mptp_t *packet);
bool lm_mptp_client_recv(int sock, lm_mptp_t *packet);

int  lm_mptp_server_listen(char *addr, uint16_t port);
int  lm_mptp_server_accept(int sock, struct sockaddr *addr);
void lm_mptp_server_close(int sock);
bool lm_mptp_server_verify(lm_mptp_t *packet);
bool lm_mptp_server_recv(int sock, lm_mptp_t *packet);
bool lm_mptp_server_send(int sock, lm_mptp_t *packet);

bool lm_mptp_sendfile(int sock, char *path, lm_mptp_transfer_callback_t callback, void *data);
bool lm_mptp_recvfile(int sock, char *path, lm_mptp_transfer_callback_t callback, void *data);