82 lines
1.6 KiB
C
82 lines
1.6 KiB
C
#include <linux/kernel.h>
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#include <linux/module.h>
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#include <net/sock.h>
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#include <net/netlink.h>
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#define NETLINK_TESTPROTO (30)
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static struct sock *my_nl_sock;
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static void nl_test_recv(struct sk_buff *skb)
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{
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struct nlmsghdr *nlh;
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int pid;
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struct sk_buff *skb_out;
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int msg_size;
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char *msg="Hello from kernel";
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int res;
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printk(KERN_INFO "Entering: %s\n", __FUNCTION__);
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msg_size=strlen(msg);
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nlh=(struct nlmsghdr*)skb->data;
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printk(KERN_INFO "Netlink received msg payload:%s\n",(char*)nlmsg_data(nlh));
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pid = nlh->nlmsg_pid; /*pid of sending process */
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skb_out = nlmsg_new(msg_size,0);
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if(!skb_out)
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{
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printk(KERN_ERR "Failed to allocate new skb\n");
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return;
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}
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nlh=nlmsg_put(skb_out,0,0,NLMSG_DONE,msg_size,0);
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NETLINK_CB(skb_out).dst_group = 0; /* not in mcast group */
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strncpy(nlmsg_data(nlh),msg,msg_size);
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res=nlmsg_unicast(my_nl_sock,skb_out,pid);
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if(res<0)
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printk(KERN_INFO "Error while sending bak to user\n");
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}
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static struct netlink_kernel_cfg nl_cfg = {
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.groups = 0,
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.input = nl_test_recv,
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};
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static int nl_test_init(void)
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{
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my_nl_sock = netlink_kernel_create(&init_net, NETLINK_TESTPROTO, &nl_cfg);
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if (!my_nl_sock) {
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printk(KERN_ERR "%s: receive handler registration failed\n", __func__);
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return -ENOMEM;
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}
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printk(KERN_INFO "Hello :)\n");
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return 0;
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}
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static void nl_test_exit(void)
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{
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if (my_nl_sock)
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netlink_kernel_release(my_nl_sock);
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printk(KERN_INFO "Goodbye :(\n");
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}
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module_init(nl_test_init);
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module_exit(nl_test_exit);
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MODULE_AUTHOR("Mario Huettel <mario.huettel@gmx.net>");
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Netlink communication test");
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