标题: 关于netlink的使用 [打印本页]
作者: sudochen    时间: 2017-5-4 09:29
标题: 关于netlink的使用
  1. /* file : genl_kernel.c
  2. * kernel module for test genetlink
  3. * sudochen@163.com
  4. *
  5. */
  6. #include <linux/init.h>
  7. #include <linux/module.h>
  8. #include <net/genetlink.h>

  10. static int cmd_echo(struct sk_buff *skb_2, struct genl_info *info);

  12. enum {
  13.     CMD_NONE,
  14.     CMD_ECHO,
  15.     CMD_MAX
  16. };

  18. static struct genl_family cmd_genl_family = {
  19.     .id = GENL_ID_GENERATE,
  20.     .hdrsize = 0,
  21.     .name = "cmd",
  22.     .version = 1,
  23.     .maxattr = CMD_MAX,
  24. };
  25.    
  26. static struct nla_policy cmd_nla_policy[CMD_MAX + 1] = {
  27.     [CMD_NONE] = {
  28.             .type = NLA_UNSPEC,
  29.     },
  30.     [CMD_ECHO] = {
  31.             .type = NLA_STRING,
  32.             .len = 0x100,
  33.     },
  34. };

  36. static struct genl_ops cmd_ops[] = {
  37.     {
  38.         .cmd = CMD_ECHO,
  39.         .flags = 0,
  40.         .policy = cmd_nla_policy,
  41.         .doit = cmd_echo,
  42.         .dumpit = NULL,
  43.     }
  44. };

  46. static int cmd_echo(struct sk_buff *skb_2, struct genl_info *info)
  47. {
  48.     struct nlattr *attr = NULL;
  49.     struct sk_buff *skb = NULL;
  50.     int ret = -1;
  51.     char *data;
  52.     char *head;
  53.     if (NULL == info) {
  54.         return -1;
  55.     }
  56.    
  57.     attr = info->attrs[CMD_ECHO];
  58.     if (attr) {
  59.         data = (char*)nla_data(attr);
  60.         if (data) {
  61.             printk("genl recv data %s\n",data);
  62.         } else {
  63.             printk("genl recv data NULL\n");
  64.         }
  65.     } else {
  66.         printk("no attr %d\n",CMD_ECHO);   
  67.     }   
  68.    
  69.     skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
  70.     if (NULL == skb) {
  71.         goto out;   
  72.     }
  73.     head = genlmsg_put(skb, 0, info->snd_seq+1,&cmd_genl_family,0,CMD_ECHO);
  74.     if (NULL == head) {
  75.         goto out;   
  76.     }
  77.     ret = nla_put_string(skb, CMD_ECHO, "hello world form kernel space");
  78.     if (ret)
  79.         goto out;
  80.     genlmsg_end(skb,head);
  81.     ret = genlmsg_unicast(&init_net,skb,info->snd_pid);
  82.     if (ret)
  83.         goto out;
  84.    
  85.     return 0;
  86. out:
  87.     printk("genl an error ocured\n");
  88.     return -1;
  89. }
  90. int __init cmd_init(void)
  91. {
  92.     int error;
  93.     error = genl_register_family_with_ops(&cmd_genl_family, cmd_ops, ARRAY_SIZE(cmd_ops));
  94.     if (error) {
  95.         printk("register family error\n");
  96.         return error;
  97.     }
  98.     printk("register family ok\n");
  99.     return 0;

  101. }

  103. void __exit cmd_exit(void)
  104. {
  105.     genl_unregister_family(&cmd_genl_family);
  106.     printk("unregister family ok\n");
  107. }
  108.    
  109. MODULE_LICENSE("GPL");
  110. module_init(cmd_init);
  111. module_exit(cmd_exit);
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