c-libp2p/include/libp2p/yamux/session.h

#pragma once

#include <stddef.h>
#include <stdint.h>
#include <time.h>
#include <sys/types.h>

#include "config.h"
#include "frame.h"
#include "stream.h"
#include "libp2p/net/stream.h"
//#include "libp2p/yamux/yamux.h"

enum yamux_session_type
{
    yamux_session_client,
    yamux_session_server
};
enum yamux_error
{
    yamux_error_normal = 0x00,
    yamux_error_protoc = 0x01,
    yamux_error_intern = 0x02
};

// forward declarations
struct yamux_session;
struct yamux_stream;
struct YamuxContext;
struct Stream;
struct StreamMessage;

typedef void* (*yamux_session_get_str_ud_fn)(struct yamux_session* session, yamux_streamid newid       );
typedef void  (*yamux_session_ping_fn      )(struct yamux_session* session, uint32_t val               );
typedef void  (*yamux_session_pong_fn      )(struct yamux_session* session, uint32_t val, struct timespec dt);
typedef void  (*yamux_session_go_away_fn   )(struct yamux_session* session, enum yamux_error err       );
typedef void  (*yamux_session_new_stream_fn)(struct YamuxContext* context, struct Stream* stream, struct StreamMessage* msg);
typedef void  (*yamux_session_free_fn      )(struct yamux_session* sesssion                            );

struct yamux_session_stream
{
    struct yamux_stream* stream;
    int alive;
};

/**
 * A yamux session. This keeps all the streams related to a yamux session
 */
struct yamux_session
{
    struct yamux_config* config; // configuration of size of windows and max number of streams

    size_t num_streams; // number of streams
    size_t cap_streams; // capacity of stream array
    struct yamux_session_stream* streams; // array of streams

    /**
     * Get user data
     */
    yamux_session_get_str_ud_fn get_str_ud_fn;
    /**
     * Ping
     */
    yamux_session_ping_fn       ping_fn      ;
    /**
     * Respond to ping
     */
    yamux_session_pong_fn       pong_fn      ;
    /**
     * Hanging up
     */
    yamux_session_go_away_fn    go_away_fn   ;
    /**
     * A new stream is coming in
     */
    yamux_session_new_stream_fn new_stream_fn;
    /**
     * Free resources
     */
    yamux_session_free_fn       free_fn      ;

    /**
     * User data
     */
    void* userdata;

    /**
     * for heartbeat
     */
    struct timespec since_ping;

    /**
     * Session type (client or server)
     */
    enum yamux_session_type type;

    /***
     * The parent stream
     */
    struct Stream* parent_stream;

    /***
     * The next id to use
     */
    yamux_streamid nextid;

    /**
     * Determine if this session is closed
     */
    int closed;
};

/***
 * Create a new yamux session
 * @param config the configuration
 * @param sock the socket
 * @param type session type (yamux_session_server or yamux_session_client)
 * @param userdata user data
 * @returns the yamux_session struct
 */
struct yamux_session* yamux_session_new(struct yamux_config* config, struct Stream* parent_stream, enum yamux_session_type type, void* userdata);

// does not close the socket, but does close the session
void yamux_session_free(struct yamux_session* session);

// does not free used memory
ssize_t yamux_session_close(struct yamux_session* session, enum yamux_error err);

inline ssize_t yamux_session_go_away(struct yamux_session* session, enum yamux_error err)
{
    return yamux_session_close(session, err);
}

ssize_t yamux_session_ping(struct yamux_session* session, uint32_t value, int pong);

// defers to stream read handlers
ssize_t yamux_session_read(struct yamux_session* session);

/**
 * Decode an incoming message
 * @param context a YamuxChannelContext or YamuxContext
 * @param incoming the incoming bytes
 * @param incoming_size the size of the incoming bytes
 * @param return_message the return message (usually the bytes after the frame)
 * @returns true(1) on success, false(0) otherwise
 */
int yamux_decode(void* context, const uint8_t* incoming, size_t incoming_size, struct StreamMessage** return_message);

/***
 * Find the correct yamux session stream
 * @param streams the collection
 * @param channel the id
 * @returns the correce yamux_session_stream
 */
struct yamux_session_stream* yamux_get_session_stream(struct yamux_session* session, int channel);