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     €БА„ЂїГВ ?ч     /* SPDX-License-Identifier: GPL-2.0 */
/*
 * General overview:
 * full generic netlink message:
 * |nlmsghdr|genlmsghdr|<payload>
 *
 * payload:
 * |optional fixed size family header|<sequence of netlink attributes>
 *
 * sequence of netlink attributes:
 * I chose to have all "top level" attributes NLA_NESTED,
 * corresponding to some real struct.
 * So we have a sequence of |tla, len|<nested nla sequence>
 *
 * nested nla sequence:
 * may be empty, or contain a sequence of netlink attributes
 * representing the struct fields.
 *
 * The tag number of any field (regardless of containing struct)
 * will be available as T_ ## field_name,
 * so you cannot have the same field name in two differnt structs.
 *
 * The tag numbers themselves are per struct, though,
 * so should always begin at 1 (not 0, that is the special "NLA_UNSPEC" type,
 * which we won't use here).
 * The tag numbers are used as index in the respective nla_policy array.
 *
 * GENL_struct(tag_name, tag_number, struct name, struct fields) - struct and policy
 *	genl_magic_struct.h
 *		generates the struct declaration,
 *		generates an entry in the tla enum,
 *	genl_magic_func.h
 *		generates an entry in the static tla policy
 *		with .type = NLA_NESTED
 *		generates the static <struct_name>_nl_policy definition,
 *		and static conversion functions
 *
 *	genl_magic_func.h
 *
 * GENL_mc_group(group)
 *	genl_magic_struct.h
 *		does nothing
 *	genl_magic_func.h
 *		defines and registers the mcast group,
 *		and provides a send helper
 *
 * GENL_notification(op_name, op_num, mcast_group, tla list)
 *	These are notifications to userspace.
 *
 *	genl_magic_struct.h
 *		generates an entry in the genl_ops enum,
 *	genl_magic_func.h
 *		does nothing
 *
 *	mcast group: the name of the mcast group this notification should be
 *	expected on
 *	tla list: the list of expected top level attributes,
 *	for documentation and sanity checking.
 *
 * GENL_op(op_name, op_num, flags and handler, tla list) - "genl operations"
 *	These are requests from userspace.
 *
 *	_op and _notification share the same "number space",
 *	op_nr will be assigned to "genlmsghdr->cmd"
 *
 *	genl_magic_struct.h
 *		generates an entry in the genl_ops enum,
 *	genl_magic_func.h
 *		generates an entry in the static genl_ops array,
 *		and static register/unregister functions to
 *		genl_register_family().
 *
 *	flags and handler:
 *		GENL_op_init( .doit = x, .dumpit = y, .flags = something)
 *		GENL_doit(x) => .dumpit = NULL, .flags = GENL_ADMIN_PERM
 *	tla list: the list of expected top level attributes,
 *	for documentation and sanity checking.
 */

/*
 * STRUCTS
 */

/* this is sent kernel -> userland on various error conditions, and contains
 * informational textual info, which is supposedly human readable.
 * The computer relevant return code is in the drbd_genlmsghdr.
 */
GENL_struct(DRBD_NLA_CFG_REPLY, 1, drbd_cfg_reply,
		/* "arbitrary" size strings, nla_policy.len = 0 */
	__str_field(1, DRBD_GENLA_F_MANDATORY,	info_text, 0)
)

/* Configuration requests typically need a context to operate on.
 * Possible keys are device minor (fits in the drbd_genlmsghdr),
 * the replication link (aka connection) name,
 * and/or the replication group (aka resource) name,
 * and the volume id within the resource. */
GENL_struct(DRBD_NLA_CFG_CONTEXT, 2, drbd_cfg_context,
	__u32_field(1, DRBD_GENLA_F_MANDATORY,	ctx_volume)
	__str_field(2, DRBD_GENLA_F_MANDATORY,	ctx_resource_name, 128)
	__bin_field(3, DRBD_GENLA_F_MANDATORY,	ctx_my_addr, 128)
	__bin_field(4, DRBD_GENLA_F_MANDATORY,	ctx_peer_addr, 128)
)

GENL_struct(DRBD_NLA_DISK_CONF, 3, disk_conf,
	__str_field(1, DRBD_F_REQUIRED | DRBD_F_INVARIANT,	backing_dev,	128)
	__str_field(2, DRBD_F_REQUIRED | DRBD_F_INVARIANT,	meta_dev,	128)
	__s32_field(3, DRBD_F_REQUIRED | DRBD_F_INVARIANT,	meta_dev_idx)

	/* use the resize command to try and change the disk_size */
	__u64_field(4, DRBD_GENLA_F_MANDATORY | DRBD_F_INVARIANT,	disk_size)
	/* we could change the max_bio_bvecs,
	 * but it won't propagate through the stack */
	__u32_field(5, D