ynl.h

  1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
  2#ifndef __YNL_C_H
  3#define __YNL_C_H 1
  4
  5#include <stdbool.h>
  6#include <stddef.h>
  7#include <linux/genetlink.h>
  8#include <linux/types.h>
  9
 10#include "ynl-priv.h"
 11
 12enum ynl_error_code {
 13	YNL_ERROR_NONE = 0,
 14	__YNL_ERRNO_END = 4096,
 15	YNL_ERROR_INTERNAL,
 16	YNL_ERROR_DUMP_INTER,
 17	YNL_ERROR_EXPECT_ACK,
 18	YNL_ERROR_EXPECT_MSG,
 19	YNL_ERROR_UNEXPECT_MSG,
 20	YNL_ERROR_ATTR_MISSING,
 21	YNL_ERROR_ATTR_INVALID,
 22	YNL_ERROR_UNKNOWN_NTF,
 23	YNL_ERROR_INV_RESP,
 24	YNL_ERROR_INPUT_INVALID,
 25	YNL_ERROR_INPUT_TOO_BIG,
 26	YNL_ERROR_SUBMSG_KEY,
 27};
 28
 29/**
 30 * struct ynl_error - error encountered by YNL
 31 * @code:	errno (low values) or YNL error code (enum ynl_error_code)
 32 * @attr_offs:	offset of bad attribute (for very advanced users)
 33 * @msg:	error message
 34 *
 35 * Error information for when YNL operations fail.
 36 * Users should interact with the err member of struct ynl_sock directly.
 37 * The main exception to that rule is ynl_sock_create().
 38 */
 39struct ynl_error {
 40	enum ynl_error_code code;
 41	unsigned int attr_offs;
 42	char msg[512];
 43};
 44
 45/**
 46 * struct ynl_family - YNL family info
 47 * Family description generated by codegen. Pass to ynl_sock_create().
 48 */
 49struct ynl_family {
 50/* private: */
 51	const char *name;
 52	size_t hdr_len;
 53	bool is_classic;
 54	__u16 classic_id;
 55	const struct ynl_ntf_info *ntf_info;
 56	unsigned int ntf_info_size;
 57};
 58
 59/**
 60 * struct ynl_sock - YNL wrapped netlink socket
 61 * @err: YNL error descriptor, cleared on every request.
 62 */
 63struct ynl_sock {
 64	struct ynl_error err;
 65
 66/* private: */
 67	const struct ynl_family *family;
 68	int socket;
 69	__u32 seq;
 70	__u32 portid;
 71	__u16 family_id;
 72
 73	unsigned int n_mcast_groups;
 74	struct {
 75		unsigned int id;
 76		char name[GENL_NAMSIZ];
 77	} *mcast_groups;
 78
 79	struct ynl_ntf_base_type *ntf_first;
 80	struct ynl_ntf_base_type **ntf_last_next;
 81
 82	struct nlmsghdr *nlh;
 83	const struct ynl_policy_nest *req_policy;
 84	size_t req_hdr_len;
 85	unsigned char *tx_buf;
 86	unsigned char *rx_buf;
 87	unsigned char raw_buf[];
 88};
 89
 90/**
 91 * struct ynl_string - parsed individual string
 92 * @len: length of the string (excluding terminating character)
 93 * @str: value of the string
 94 *
 95 * Parsed and nul-terminated string. This struct is only used for arrays of
 96 * strings. Non-array string members are placed directly in respective types.
 97 */
 98struct ynl_string {
 99	unsigned int len;
100	char str[];
101};
102
103struct ynl_sock *
104ynl_sock_create(const struct ynl_family *yf, struct ynl_error *e);
105void ynl_sock_destroy(struct ynl_sock *ys);
106
107#define ynl_dump_foreach(dump, iter)					\
108	for (typeof(dump->obj) *iter = &dump->obj;			\
109	     !ynl_dump_obj_is_last(iter);				\
110	     iter = ynl_dump_obj_next(iter))
111
112/**
113 * ynl_dump_empty() - does the dump have no entries
114 * @dump: pointer to the dump list, as returned by a dump call
115 *
116 * Check if the dump is empty, i.e. contains no objects.
117 * Dump calls return NULL on error, and terminator element if empty.
118 */
119static inline bool ynl_dump_empty(void *dump)
120{
121	return dump == (void *)YNL_LIST_END;
122}
123
124int ynl_subscribe(struct ynl_sock *ys, const char *grp_name);
125int ynl_socket_get_fd(struct ynl_sock *ys);
126int ynl_ntf_check(struct ynl_sock *ys);
127
128/**
129 * ynl_has_ntf() - check if socket has *parsed* notifications
130 * @ys: active YNL socket
131 *
132 * Note that this does not take into account notifications sitting
133 * in netlink socket, just the notifications which have already been
134 * read and parsed (e.g. during a ynl_ntf_check() call).
135 */
136static inline bool ynl_has_ntf(struct ynl_sock *ys)
137{
138	return ys->ntf_last_next != &ys->ntf_first;
139}
140struct ynl_ntf_base_type *ynl_ntf_dequeue(struct ynl_sock *ys);
141
142void ynl_ntf_free(struct ynl_ntf_base_type *ntf);
143#endif