#pragma once

#include <stdlib.h>
#include <stdint.h>


#define PROTM_MAX_SIZE 65536

#define PROTM_TYPE_ESTAB 1
#define PROTM_TYPE_TERM 2
#define PROTM_TYPE_DATA 3
#define PROTM_TYPE_RR 4
#define PROTM_TYPE_RR_POLL 5

struct __attribute__((packed)) protm {
	uint8_t type;
	union {
		struct {
			uint8_t ack;
		} estab;
		struct {
			uint8_t ack;
		} term;
		struct {
			uint8_t seqnum, rr;
			uint32_t size;
			// An IPv4 packet is at most 65536 bytes, so the data portion
			// left after allowing for the IPv4 and ICMP headers as well
			// as those for this protocol, is surely at most 65536 bytes.
			uint8_t data[65536];
		} data;
		struct {
			uint8_t rr, nrej;
			uint8_t rej[256];
		} rr;
		struct {
			// empty
		} rr_poll;
	};
};

size_t protm_size(const struct protm *pm);