firehol/netdata

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

package openvpn_status_log

import (
    "bufio"
    "fmt"
    "os"
    "strconv"
    "strings"
    "time"
)

type clientInfo struct {
    commonName     string
    bytesReceived  int64
    bytesSent      int64
    connectedSince int64
}

func parse(path string) ([]clientInfo, error) {
    f, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer func() { _ = f.Close() }()

    sc := bufio.NewScanner(f)
    _ = sc.Scan()
    line := sc.Text()

    if line == "OpenVPN CLIENT LIST" {
        return parseV1(sc), nil
    }
    if strings.HasPrefix(line, "TITLE,OpenVPN") || strings.HasPrefix(line, "TITLE\tOpenVPN") {
        return parseV2V3(sc), nil
    }
    if line == "OpenVPN STATISTICS" {
        return parseStaticKey(sc), nil
    }
    return nil, fmt.Errorf("the status log file is invalid (%s)", path)
}

func parseV1(sc *bufio.Scanner) []clientInfo {
    // https://github.com/OpenVPN/openvpn/blob/d5315a5d7400a26f1113bbc44766d49dd0c3688f/src/openvpn/multi.c#L836
    var clients []clientInfo

    for sc.Scan() {
        if !strings.HasPrefix(sc.Text(), "Common Name") {
            continue
        }
        for sc.Scan() && !strings.HasPrefix(sc.Text(), "ROUTING TABLE") {
            parts := strings.Split(sc.Text(), ",")
            if len(parts) != 5 {
                continue
            }

            name := parts[0]
            bytesRx, _ := strconv.ParseInt(parts[2], 10, 64)
            bytesTx, _ := strconv.ParseInt(parts[3], 10, 64)
            connSince, _ := time.Parse("Mon Jan 2 15:04:05 2006", parts[4])

            clients = append(clients, clientInfo{
                commonName:     name,
                bytesReceived:  bytesRx,
                bytesSent:      bytesTx,
                connectedSince: connSince.Unix(),
            })
        }
        break
    }
    return clients
}

func parseV2V3(sc *bufio.Scanner) []clientInfo {
    // https://github.com/OpenVPN/openvpn/blob/d5315a5d7400a26f1113bbc44766d49dd0c3688f/src/openvpn/multi.c#L901
    var clients []clientInfo
    var sep string
    if strings.IndexByte(sc.Text(), '\t') != -1 {
        sep = "\t"
    } else {
        sep = ","
    }

    for sc.Scan() {
        line := sc.Text()
        if !strings.HasPrefix(line, "CLIENT_LIST") {
            continue
        }
        parts := strings.Split(line, sep)
        if len(parts) != 13 {
            continue
        }

        name := parts[1]
        bytesRx, _ := strconv.ParseInt(parts[5], 10, 64)
        bytesTx, _ := strconv.ParseInt(parts[6], 10, 64)
        connSince, _ := strconv.ParseInt(parts[8], 10, 64)

        clients = append(clients, clientInfo{
            commonName:     name,
            bytesReceived:  bytesRx,
            bytesSent:      bytesTx,
            connectedSince: connSince,
        })
    }
    return clients
}

func parseStaticKey(sc *bufio.Scanner) []clientInfo {
    // https://github.com/OpenVPN/openvpn/blob/d5315a5d7400a26f1113bbc44766d49dd0c3688f/src/openvpn/sig.c#L283
    var info clientInfo
    for sc.Scan() {
        line := sc.Text()
        if !strings.HasPrefix(line, "TCP/UDP") {
            continue
        }
        i := strings.IndexByte(line, ',')
        if i == -1 || len(line) == i {
            continue
        }
        bytes, _ := strconv.ParseInt(line[i+1:], 10, 64)
        switch line[:i] {
        case "TCP/UDP read bytes":
            info.bytesReceived += bytes
        case "TCP/UDP write bytes":
            info.bytesSent += bytes
        }
    }
    return []clientInfo{info}
}