connector.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * 	connector.h
  4 * 
  5 * 2004-2005 Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
  6 * All rights reserved.
  7 */
  8#ifndef __CONNECTOR_H
  9#define __CONNECTOR_H
 10
 11
 12#include <linux/refcount.h>
 13
 14#include <linux/list.h>
 15#include <linux/workqueue.h>
 16
 17#include <net/sock.h>
 18#include <uapi/linux/connector.h>
 19
 20#define CN_CBQ_NAMELEN		32
 21
 22struct cn_queue_dev {
 23	atomic_t refcnt;
 24	unsigned char name[CN_CBQ_NAMELEN];
 25
 26	struct list_head queue_list;
 27	spinlock_t queue_lock;
 28
 29	struct sock *nls;
 30};
 31
 32struct cn_callback_id {
 33	unsigned char name[CN_CBQ_NAMELEN];
 34	struct cb_id id;
 35};
 36
 37struct cn_callback_entry {
 38	struct list_head callback_entry;
 39	refcount_t refcnt;
 40	struct cn_queue_dev *pdev;
 41
 42	struct cn_callback_id id;
 43	void (*callback) (struct cn_msg *, struct netlink_skb_parms *);
 44
 45	u32 seq, group;
 46};
 47
 48struct cn_dev {
 49	struct cb_id id;
 50
 51	u32 seq, groups;
 52	struct sock *nls;
 53
 54	struct cn_queue_dev *cbdev;
 55};
 56
 57/**
 58 * cn_add_callback() - Registers new callback with connector core.
 59 *
 60 * @id:		unique connector's user identifier.
 61 *		It must be registered in connector.h for legal
 62 *		in-kernel users.
 63 * @name:	connector's callback symbolic name.
 64 * @callback:	connector's callback.
 65 * 		parameters are %cn_msg and the sender's credentials
 66 */
 67int cn_add_callback(const struct cb_id *id, const char *name,
 68		    void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
 69/**
 70 * cn_del_callback() - Unregisters new callback with connector core.
 71 *
 72 * @id:		unique connector's user identifier.
 73 */
 74void cn_del_callback(const struct cb_id *id);
 75
 76
 77/**
 78 * cn_netlink_send_mult - Sends message to the specified groups.
 79 *
 80 * @msg: 	message header(with attached data).
 81 * @len:	Number of @msg to be sent.
 82 * @portid:	destination port.
 83 *		If non-zero the message will be sent to the given port,
 84 *		which should be set to the original sender.
 85 * @group:	destination group.
 86 * 		If @portid and @group is zero, then appropriate group will
 87 *		be searched through all registered connector users, and
 88 *		message will be delivered to the group which was created
 89 *		for user with the same ID as in @msg.
 90 *		If @group is not zero, then message will be delivered
 91 *		to the specified group.
 92 * @gfp_mask:	GFP mask.
 93 * @filter:     Filter function to be used at netlink layer.
 94 * @filter_data:Filter data to be supplied to the filter function
 95 *
 96 * It can be safely called from softirq context, but may silently
 97 * fail under strong memory pressure.
 98 *
 99 * If there are no listeners for given group %-ESRCH can be returned.
100 */
101int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid,
102			 u32 group, gfp_t gfp_mask,
103			 netlink_filter_fn filter,
104			 void *filter_data);
105
106/**
107 * cn_netlink_send - Sends message to the specified groups.
108 *
109 * @msg:	message header(with attached data).
110 * @portid:	destination port.
111 *		If non-zero the message will be sent to the given port,
112 *		which should be set to the original sender.
113 * @group:	destination group.
114 * 		If @portid and @group is zero, then appropriate group will
115 *		be searched through all registered connector users, and
116 *		message will be delivered to the group which was created
117 *		for user with the same ID as in @msg.
118 *		If @group is not zero, then message will be delivered
119 *		to the specified group.
120 * @gfp_mask:	GFP mask.
121 *
122 * It can be safely called from softirq context, but may silently
123 * fail under strong memory pressure.
124 *
125 * If there are no listeners for given group %-ESRCH can be returned.
126 */
127int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
128
129int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
130			  const struct cb_id *id,
131			  void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
132void cn_queue_del_callback(struct cn_queue_dev *dev, const struct cb_id *id);
133void cn_queue_release_callback(struct cn_callback_entry *);
134
135struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *);
136void cn_queue_free_dev(struct cn_queue_dev *dev);
137
138int cn_cb_equal(const struct cb_id *, const struct cb_id *);
139
140#endif				/* __CONNECTOR_H */