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 
22 struct 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 
32 struct cn_callback_id {
33 	unsigned char name[CN_CBQ_NAMELEN];
34 	struct cb_id id;
35 };
36 
37 struct 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 
48 struct 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  */
67 int 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  */
74 void 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  *
94  * It can be safely called from softirq context, but may silently
95  * fail under strong memory pressure.
96  *
97  * If there are no listeners for given group %-ESRCH can be returned.
98  */
99 int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 group, gfp_t gfp_mask);
100 
101 /**
102  * cn_netlink_send - Sends message to the specified groups.
103  *
104  * @msg:	message header(with attached data).
105  * @portid:	destination port.
106  *		If non-zero the message will be sent to the given port,
107  *		which should be set to the original sender.
108  * @group:	destination group.
109  * 		If @portid and @group is zero, then appropriate group will
110  *		be searched through all registered connector users, and
111  *		message will be delivered to the group which was created
112  *		for user with the same ID as in @msg.
113  *		If @group is not zero, then message will be delivered
114  *		to the specified group.
115  * @gfp_mask:	GFP mask.
116  *
117  * It can be safely called from softirq context, but may silently
118  * fail under strong memory pressure.
119  *
120  * If there are no listeners for given group %-ESRCH can be returned.
121  */
122 int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 group, gfp_t gfp_mask);
123 
124 int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
125 			  const struct cb_id *id,
126 			  void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
127 void cn_queue_del_callback(struct cn_queue_dev *dev, const struct cb_id *id);
128 void cn_queue_release_callback(struct cn_callback_entry *);
129 
130 struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *);
131 void cn_queue_free_dev(struct cn_queue_dev *dev);
132 
133 int cn_cb_equal(const struct cb_id *, const struct cb_id *);
134 
135 #endif				/* __CONNECTOR_H */
136