从内核获取TCP端口的监听进程

static void get_task_from_sock(struct sock *sk)
{
    struct socket *sock = NULL;
    struct file *file = NULL;
    struct task_struct *task;
    int i, j = 0;
    struct fdtable *fdt;
    int found = 0;
    if (sk == NULL)
        return;

    sock = sk->sk_socket;
    if (sock == NULL)
        return;

    file = sock->file;

    rcu_read_lock();
    for_each_process(task) {
        fdt = task->files->fdt;
        if (fdt) {
            j = fdt->max_fds;
            for (i = 0; i < j; i++) {
                if (NULL != fdt->fd[i]) {
                    if (fdt->fd[i] == file) {
                        printk("task name %s bind %d\n", task->comm, inet_sk(sk)->inet_num);
                        found = 1;
                        break;
                    }
                }
            }
        }
        if (found == 1)
            break;
    }
    rcu_read_unlock();

    return;
}

static void get_listen_task(void)
{
    int i = 0;
    char port_str[8] = {0};

    struct sock *sk;
    struct hlist_nulls_node *node;
    struct inet_listen_hashbucket *ilb;

    rcu_read_lock();
    for (i = 0; i < INET_LHTABLE_SIZE; i++) {
        ilb = &tcp_hashinfo.listening_hash[i];
        sk_nulls_for_each_rcu(sk, node, &ilb->head) {
            if (sk) {
                    if (sk->sk_family != AF_INET)
                        continue;

                    memset(port_str, 0, sizeof(port_str));
                #if LINUX_VERSION_CODE < KERNEL_VERSION(3,8,0)
                    snprintf(port_str, sizeof(port_str), "%d", inet_sk(sk)->num);
                    get_task_from_sock(sk);
                #else
                    snprintf(port_str, sizeof(port_str), "%d", inet_sk(sk)->inet_num);
                    get_task_from_sock(sk);
                #endif
            }
        }
    }
    rcu_read_unlock();

    return;
}