mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-13 20:12:26 +00:00
50 lines
1.3 KiB
C
50 lines
1.3 KiB
C
#include <linux/netlink.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#define MAX_PAYLOAD 1024
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#define NETLINK_USER 31
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/* Some of these structs fields must be zeroed.
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* We could brute force memset them, but
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* TODO determine exactly which, and move into main. */
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int sock_fd;
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struct iovec iov;
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struct msghdr msg;
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struct nlmsghdr *nlh;
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struct sockaddr_nl src_addr, dest_addr;
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int main()
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{
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sock_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_USER);
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if (sock_fd < 0) {
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perror("socket");
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return EXIT_FAILURE;
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}
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src_addr.nl_family = AF_NETLINK;
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src_addr.nl_pid = getpid();
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bind(sock_fd, (struct sockaddr *)&src_addr, sizeof(src_addr));
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dest_addr.nl_family = AF_NETLINK;
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nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));
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memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));
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nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
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nlh->nlmsg_pid = getpid();
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nlh->nlmsg_flags = 0;
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strcpy(NLMSG_DATA(nlh), "user request");
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iov.iov_base = (void *)nlh;
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iov.iov_len = nlh->nlmsg_len;
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msg.msg_name = (void *)&dest_addr;
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msg.msg_namelen = sizeof(dest_addr);
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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printf("before sendmsg\n");
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sendmsg(sock_fd, &msg, 0);
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printf("after sendmsg\n");
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recvmsg(sock_fd, &msg, 0);
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printf("userland received: %s\n", (char *)NLMSG_DATA(nlh));
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close(sock_fd);
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}
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