1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * 	cn_test.c
4  *
5  * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
6  * All rights reserved.
7  */
8 
9 #define pr_fmt(fmt) "cn_test: " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/skbuff.h>
15 #include <linux/slab.h>
16 #include <linux/timer.h>
17 
18 #include <linux/connector.h>
19 
20 static struct cb_id cn_test_id = { CN_NETLINK_USERS + 3, 0x456 };
21 static char cn_test_name[] = "cn_test";
22 static struct sock *nls;
23 static struct timer_list cn_test_timer;
24 
cn_test_callback(struct cn_msg * msg,struct netlink_skb_parms * nsp)25 static void cn_test_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
26 {
27 	pr_info("%s: %lu: idx=%x, val=%x, seq=%u, ack=%u, len=%d: %s.\n",
28 	        __func__, jiffies, msg->id.idx, msg->id.val,
29 	        msg->seq, msg->ack, msg->len,
30 	        msg->len ? (char *)msg->data : "");
31 }
32 
33 /*
34  * Do not remove this function even if no one is using it as
35  * this is an example of how to get notifications about new
36  * connector user registration
37  */
38 #if 0
39 static int cn_test_want_notify(void)
40 {
41 	struct cn_ctl_msg *ctl;
42 	struct cn_notify_req *req;
43 	struct cn_msg *msg = NULL;
44 	int size, size0;
45 	struct sk_buff *skb;
46 	struct nlmsghdr *nlh;
47 	u32 group = 1;
48 
49 	size0 = sizeof(*msg) + sizeof(*ctl) + 3 * sizeof(*req);
50 
51 	size = NLMSG_SPACE(size0);
52 
53 	skb = alloc_skb(size, GFP_ATOMIC);
54 	if (!skb) {
55 		pr_err("failed to allocate new skb with size=%u\n", size);
56 		return -ENOMEM;
57 	}
58 
59 	nlh = nlmsg_put(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh), 0);
60 	if (!nlh) {
61 		kfree_skb(skb);
62 		return -EMSGSIZE;
63 	}
64 
65 	msg = nlmsg_data(nlh);
66 
67 	memset(msg, 0, size0);
68 
69 	msg->id.idx = -1;
70 	msg->id.val = -1;
71 	msg->seq = 0x123;
72 	msg->ack = 0x345;
73 	msg->len = size0 - sizeof(*msg);
74 
75 	ctl = (struct cn_ctl_msg *)(msg + 1);
76 
77 	ctl->idx_notify_num = 1;
78 	ctl->val_notify_num = 2;
79 	ctl->group = group;
80 	ctl->len = msg->len - sizeof(*ctl);
81 
82 	req = (struct cn_notify_req *)(ctl + 1);
83 
84 	/*
85 	 * Idx.
86 	 */
87 	req->first = cn_test_id.idx;
88 	req->range = 10;
89 
90 	/*
91 	 * Val 0.
92 	 */
93 	req++;
94 	req->first = cn_test_id.val;
95 	req->range = 10;
96 
97 	/*
98 	 * Val 1.
99 	 */
100 	req++;
101 	req->first = cn_test_id.val + 20;
102 	req->range = 10;
103 
104 	NETLINK_CB(skb).dst_group = ctl->group;
105 	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
106 	netlink_unicast(nls, skb, 0, 0);
107 
108 	pr_info("request was sent: group=0x%x\n", ctl->group);
109 
110 	return 0;
111 }
112 #endif
113 
114 static u32 cn_test_timer_counter;
cn_test_timer_func(struct timer_list * unused)115 static void cn_test_timer_func(struct timer_list *unused)
116 {
117 	struct cn_msg *m;
118 	char data[32];
119 
120 	pr_debug("%s: timer fired\n", __func__);
121 
122 	m = kzalloc(sizeof(*m) + sizeof(data), GFP_ATOMIC);
123 	if (m) {
124 
125 		memcpy(&m->id, &cn_test_id, sizeof(m->id));
126 		m->seq = cn_test_timer_counter;
127 		m->len = sizeof(data);
128 
129 		m->len =
130 		    scnprintf(data, sizeof(data), "counter = %u",
131 			      cn_test_timer_counter) + 1;
132 
133 		memcpy(m + 1, data, m->len);
134 
135 		cn_netlink_send(m, 0, 0, GFP_ATOMIC);
136 		kfree(m);
137 	}
138 
139 	cn_test_timer_counter++;
140 
141 	mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));
142 }
143 
cn_test_init(void)144 static int cn_test_init(void)
145 {
146 	int err;
147 
148 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
149 	if (err)
150 		goto err_out;
151 	cn_test_id.val++;
152 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
153 	if (err) {
154 		cn_del_callback(&cn_test_id);
155 		goto err_out;
156 	}
157 
158 	timer_setup(&cn_test_timer, cn_test_timer_func, 0);
159 	mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));
160 
161 	pr_info("initialized with id={%u.%u}\n",
162 		cn_test_id.idx, cn_test_id.val);
163 
164 	return 0;
165 
166       err_out:
167 	if (nls && nls->sk_socket)
168 		sock_release(nls->sk_socket);
169 
170 	return err;
171 }
172 
cn_test_fini(void)173 static void cn_test_fini(void)
174 {
175 	del_timer_sync(&cn_test_timer);
176 	cn_del_callback(&cn_test_id);
177 	cn_test_id.val--;
178 	cn_del_callback(&cn_test_id);
179 	if (nls && nls->sk_socket)
180 		sock_release(nls->sk_socket);
181 }
182 
183 module_init(cn_test_init);
184 module_exit(cn_test_fini);
185 
186 MODULE_LICENSE("GPL");
187 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
188 MODULE_DESCRIPTION("Connector's test module");
189