mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-13 20:12:26 +00:00
67 lines
1.4 KiB
C
67 lines
1.4 KiB
C
/* https://cirosantilli.com/linux-kernel-module-cheat#netlink-sockets */
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#include <linux/delay.h> /* usleep_range */
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <lkmc/netlink.h>
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struct sock *nl_sk = NULL;
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static u32 count;
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static u32 sleep;
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module_param(sleep, int, S_IRUSR | S_IWUSR);
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static void callback(struct sk_buff *skb)
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{
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char readbuf[9];
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size_t readbuflen;
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int pid;
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int res;
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struct nlmsghdr *nlh;
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struct sk_buff *skb_out;
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nlh = (struct nlmsghdr *)skb->data;
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pr_info("kernel received: %s\n", (char *)nlmsg_data(nlh));
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if (sleep)
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usleep_range(1000000, 1000001);
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readbuflen = snprintf(readbuf, sizeof(readbuf), "%x", count);
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count++;
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pid = nlh->nlmsg_pid;
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skb_out = nlmsg_new(readbuflen, 0);
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if (!skb_out) {
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pr_err("nlmsg_new\n");
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return;
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}
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nlh = nlmsg_put(skb_out, 0, 0, NLMSG_DONE, readbuflen, 0);
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NETLINK_CB(skb_out).dst_group = 0;
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strncpy(nlmsg_data(nlh), readbuf, readbuflen);
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res = nlmsg_unicast(nl_sk, skb_out, pid);
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if (res < 0)
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pr_info("nlmsg_unicast\n");
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}
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static int myinit(void)
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{
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struct netlink_kernel_cfg cfg = {
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.input = callback,
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};
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nl_sk = netlink_kernel_create(&init_net, NETLINK_USER, &cfg);
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if (!nl_sk) {
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pr_err("netlink_kernel_create\n");
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return -10;
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}
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return 0;
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}
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static void myexit(void)
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{
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netlink_kernel_release(nl_sk);
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}
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module_init(myinit);
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module_exit(myexit);
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MODULE_LICENSE("GPL");
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