/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright (c) 2025 Red Hat GmbH
 * Author: Stefano Brivio <sbrivio@redhat.com>
 */
 
#ifndef MIGRATE_H
#define MIGRATE_H

/**
 * struct migrate_meta - Migration metadata
 * @v:			Chosen migration data version, host order
 * @bswap:		Source has opposite endianness
 * @peer_64b:		Source uses 64-bit void *
 * @time_64b:		Source uses 64-bit time_t
 * @flow_size:		Size of union flow in source
 * @flow_sidx_size:	Size of struct flow_sidx in source
 */
struct migrate_meta {
	uint32_t v;
	bool bswap;
	bool source_64b;
	bool time_64b;
	size_t flow_size;
	size_t flow_sidx_size;
};

/**
 * union migrate_header - Migration header from source
 * @magic:		0xB1BB1D1B0BB1D1B0, host order
 * @version:		Source sends highest known, target aborts if unsupported
 * @voidp_size:		sizeof(void *), network order
 * @time_t_size:	sizeof(time_t), network order
 * @flow_size:		sizeof(union flow), network order
 * @flow_sidx_size:	sizeof(struct flow_sidx_t), network order
 * @unused:		Go figure
 */
union migrate_header {
	struct {
		uint64_t magic;
		uint32_t version;
		uint32_t voidp_size;
		uint32_t time_t_size;
		uint32_t flow_size;
		uint32_t flow_sidx_size;
	};
	uint8_t unused[65536];
};

/**
 * struct migrate_data - Data sections for given source version
 * @v:			Source version this applies to, host order
 * @sections:		Array of data sections, NULL-terminated
 */
struct migrate_data {
	uint32_t v;
	struct iovec *sections;
};

/**
 * struct migrate_handler - Function to handle a specific data section
 * @fn:			Function pointer taking pointer to context and metadata
 */
struct migrate_handler {
	int (*fn)(struct ctx *c, struct migrate_meta *m);
};

/**
 * struct migrate_target_handlers - Versioned sets of migration target handlers
 * @v:			Source version this applies to, host order
 * @pre:		Set of functions to execute in target before data copy
 * @post:		Set of functions to execute in target after data copy
 */
struct migrate_target_handlers {
	uint32_t v;
	struct migrate_handler *pre;
	struct migrate_handler *post;
};

void migrate_init(struct ctx *c);
void migrate_close(struct ctx *c);
void migrate_request(struct ctx *c, int fd, bool target);
void migrate_handler(struct ctx *c, uint32_t events);

#endif /* MIGRATE_H */