c-libp2p/include/libp2p/secio/exchange.h

#pragma once

#include "libp2p/crypto/rsa.h"
#include "libp2p/conn/session.h"

struct Exchange {
	unsigned char* epubkey;
	size_t epubkey_size;
	unsigned char* signature;
	size_t signature_size;
};

struct Exchange* libp2p_secio_exchange_new();
void libp2p_secio_exchange_free(struct Exchange* in);

/**
 * retrieves the approximate size of an encoded version of the passed in struct
 * @param in the struct to look at
 * @reutrns the size of buffer needed
 */
size_t libp2p_secio_exchange_protobuf_encode_size(struct Exchange* in);

/**
 * Encode the struct Exchange in protobuf format
 * @param in the struct to be encoded
 * @param buffer where to put the results
 * @param max_buffer_length the max to write
 * @param bytes_written how many bytes were written to the buffer
 * @returns true(1) on success, otherwise false(0)
 */
int libp2p_secio_exchange_protobuf_encode(struct Exchange* in, unsigned char* buffer, size_t max_buffer_length, size_t* bytes_written);

/**
 * Turns a protobuf array into an Exchange struct
 * @param buffer the protobuf array
 * @param max_buffer_length the length of the buffer
 * @param out a pointer to the new struct Exchange NOTE: this method allocates memory
 * @returns true(1) on success, otherwise false(0)
 */
int libp2p_secio_exchange_protobuf_decode(unsigned char* buffer, size_t max_buffer_length, struct Exchange** out);

/***
 * Build an exchange object based on passed in values
 * @param local_session the SessionContext
 * @param private_key the local RsaPrivateKey
 * @param bytes_to_be_signed the bytes that should be signed
 * @param bytes_size the length of bytes_to_be_signed
 * @returns an Exchange object or NULL
 */
struct Exchange* libp2p_secio_exchange_build(struct SessionContext* local_session, struct RsaPrivateKey* private_key, const char* bytes_to_be_signed, size_t bytes_size);