Function fetchDnsWithFallback

bgp/bgp.ts:156–188

(ip: string)

    const prefixesToTry: string[] = [];
    const p24 = networkAddress(ip, 24);
    if (p24) prefixesToTry.push(p24);
    const p23 = networkAddress(ip, 23);
    if (p23 && p23 !== p24) prefixesToTry.push(p23);

    for (const prefix of prefixesToTry) {
        const url = `https://bgp.tools/prefix/${prefix}#dns`;

        try {
            const response = await axios.get(url, {
                headers: BGP_COMMON_HEADERS,
                timeout: 15000,
            });

            const dnsResult = extractDNSData(response.data);

            if (dnsResult.dnsLines.length > 0) {
                return { dnsLines: dnsResult.dnsLines, usedPrefix: prefix };
            }
        } catch (err: any) {
            if (err.response?.status === 404) continue;
            continue;
        }
    }

    throw new Error("未找到DNS记录");
}

function extractTopLevelDomain(domain: string): string {
    const parts = domain.split(".");
    if (parts.length >= 2) return parts.slice(-2).join(".");
    return domain;
}

function extractDNSData(html: string): {
    dnsLines: string[];
    totalRecords: number;