tools/net/ynl/lib/ynl.h

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
#ifndef __YNL_C_H
#define __YNL_C_H 1

#include <stddef.h>
#include <linux/genetlink.h>
#include <linux/types.h>

#include "ynl-priv.h"

enum ynl_error_code {
	YNL_ERROR_NONE = 0,
	__YNL_ERRNO_END = 4096,
	YNL_ERROR_INTERNAL,
	YNL_ERROR_DUMP_INTER,
	YNL_ERROR_EXPECT_ACK,
	YNL_ERROR_EXPECT_MSG,
	YNL_ERROR_UNEXPECT_MSG,
	YNL_ERROR_ATTR_MISSING,
	YNL_ERROR_ATTR_INVALID,
	YNL_ERROR_UNKNOWN_NTF,
	YNL_ERROR_INV_RESP,
	YNL_ERROR_INPUT_INVALID,
	YNL_ERROR_INPUT_TOO_BIG,
};

/**
 * struct ynl_error - error encountered by YNL
 * @code:	errno (low values) or YNL error code (enum ynl_error_code)
 * @attr_offs:	offset of bad attribute (for very advanced users)
 * @msg:	error message
 *
 * Error information for when YNL operations fail.
 * Users should interact with the err member of struct ynl_sock directly.
 * The main exception to that rule is ynl_sock_create().
 */
struct ynl_error {
	enum ynl_error_code code;
	unsigned int attr_offs;
	char msg[512];
};

/**
 * struct ynl_family - YNL family info
 * Family description generated by codegen. Pass to ynl_sock_create().
 */
struct ynl_family {
/* private: */
	const char *name;
	size_t hdr_len;
	const struct ynl_ntf_info *ntf_info;
	unsigned int ntf_info_size;
};

/**
 * struct ynl_sock - YNL wrapped netlink socket
 * @err: YNL error descriptor, cleared on every request.
 */
struct ynl_sock {
	struct ynl_error err;

/* private: */
	const struct ynl_family *family;
	int socket;
	__u32 seq;
	__u32 portid;
	__u16 family_id;

	unsigned int n_mcast_groups;
	struct {
		unsigned int id;
		char name[GENL_NAMSIZ];
	} *mcast_groups;

	struct ynl_ntf_base_type *ntf_first;
	struct ynl_ntf_base_type **ntf_last_next;

	struct nlmsghdr *nlh;
	const struct ynl_policy_nest *req_policy;
	unsigned char *tx_buf;
	unsigned char *rx_buf;
	unsigned char raw_buf[];
};

struct ynl_sock *
ynl_sock_create(const struct ynl_family *yf, struct ynl_error *e);
void ynl_sock_destroy(struct ynl_sock *ys);

#define ynl_dump_foreach(dump, iter)					\
	for (typeof(dump->obj) *iter = &dump->obj;			\
	     !ynl_dump_obj_is_last(iter);				\
	     iter = ynl_dump_obj_next(iter))

/**
 * ynl_dump_empty() - does the dump have no entries
 * @dump: pointer to the dump list, as returned by a dump call
 *
 * Check if the dump is empty, i.e. contains no objects.
 * Dump calls return NULL on error, and terminator element if empty.
 */
static inline bool ynl_dump_empty(void *dump)
{
	return dump == (void *)YNL_LIST_END;
}

int ynl_subscribe(struct ynl_sock *ys, const char *grp_name);
int ynl_socket_get_fd(struct ynl_sock *ys);
int ynl_ntf_check(struct ynl_sock *ys);

/**
 * ynl_has_ntf() - check if socket has *parsed* notifications
 * @ys: active YNL socket
 *
 * Note that this does not take into account notifications sitting
 * in netlink socket, just the notifications which have already been
 * read and parsed (e.g. during a ynl_ntf_check() call).
 */
static inline bool ynl_has_ntf(struct ynl_sock *ys)
{
	return ys->ntf_last_next != &ys->ntf_first;
}
struct ynl_ntf_base_type *ynl_ntf_dequeue(struct ynl_sock *ys);

void ynl_ntf_free(struct ynl_ntf_base_type *ntf);
#endif