firehol/netdata

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

package entnum

import (
    "bufio"
    "bytes"
    _ "embed"
    "strconv"
    "strings"
)

// https://www.iana.org/assignments/enterprise-numbers.txt
//
//go:embed "enterprise-numbers.txt"
var enterpriseNumberTxt []byte

func LookupBySysObject(sysObject string) string {
    return numbers[extractEntNumber(sysObject)]
}

var numbers = func() map[string]string {
    if len(enterpriseNumberTxt) == 0 {
        panic("snmp: enterprise-numbers.txt is empty")
    }

    mapping := make(map[string]string, 65000)

    vr := strings.NewReplacer("\"", "", "`", "", "\\", "")
    var id string

    sc := bufio.NewScanner(bytes.NewReader(enterpriseNumberTxt))

    for sc.Scan() {
        line := strings.TrimSpace(sc.Text())
        if line == "" {
            continue
        }

        if _, err := strconv.Atoi(line); err == nil {
            if id == "" {
                id = line
                if _, ok := mapping[id]; ok {
                    panic("snmp: duplicate entry number: " + line)
                }
            }
            continue
        }
        if id != "" {
            line = vr.Replace(line)
            if line == "---none---" || line == "Reserved" {
                id = ""
                continue
            }
            mapping[id] = line
            id = ""
        }
    }

    if len(mapping) == 0 {
        panic("snmp: enterprise-numbers mapping is empty after reading enterprise-numbers.txt")
    }

    return mapping
}()

func extractEntNumber(sysObject string) string {
    const rootOidIanaPEN = "1.3.6.1.4.1"

    // .1.3.6.1.4.1.14988.1 => 14988

    sysObject = strings.TrimPrefix(sysObject, ".")

    s := strings.TrimPrefix(sysObject, rootOidIanaPEN+".")

    num, _, ok := strings.Cut(s, ".")
    if !ok {
        return ""
    }

    return num
}