samples/connector/cn_test.c

   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
  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;
 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
 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
 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");