firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package ntpd

import (
    "net"
    "time"

    "github.com/facebook/time/ntp/control"
)

func newNTPClient(c Config) (ntpConn, error) {
    conn, err := net.DialTimeout("udp", c.Address, c.Timeout.Duration())
    if err != nil {
        return nil, err
    }

    client := &ntpClient{
        conn:    conn,
        timeout: c.Timeout.Duration(),
        client:  &control.NTPClient{Connection: conn},
    }

    return client, nil
}

type ntpClient struct {
    conn    net.Conn
    timeout time.Duration
    client  *control.NTPClient
}

func (c *ntpClient) systemInfo() (map[string]string, error) {
    return c.peerInfo(0)
}

func (c *ntpClient) peerInfo(id uint16) (map[string]string, error) {
    msg := &control.NTPControlMsgHead{
        VnMode:        control.MakeVnMode(2, control.Mode),
        REMOp:         control.OpReadVariables,
        AssociationID: id,
    }

    if err := c.conn.SetDeadline(time.Now().Add(c.timeout)); err != nil {
        return nil, err
    }

    resp, err := c.client.Communicate(msg)
    if err != nil {
        return nil, err
    }

    return resp.GetAssociationInfo()
}

func (c *ntpClient) peerIDs() ([]uint16, error) {
    msg := &control.NTPControlMsgHead{
        VnMode: control.MakeVnMode(2, control.Mode),
        REMOp:  control.OpReadStatus,
    }

    if err := c.conn.SetDeadline(time.Now().Add(c.timeout)); err != nil {
        return nil, err
    }

    resp, err := c.client.Communicate(msg)
    if err != nil {
        return nil, err
    }

    peers, err := resp.GetAssociations()
    if err != nil {
        return nil, err
    }

    var ids []uint16
    for id := range peers {
        ids = append(ids, id)
    }

    return ids, nil
}

func (c *ntpClient) close() {
    if c.conn != nil {
        _ = c.conn.Close()
        c.conn = nil
    }
}