89 lines
1.8 KiB
Go
89 lines
1.8 KiB
Go
package utils
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import (
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"context"
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"net"
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"os"
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"strings"
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"time"
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"git.gay/gitgay/pages/errors"
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)
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var (
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DNS_SERVER string
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ourIPs []net.IP
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Resolver *net.Resolver
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)
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func init() {
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dnsServer, ok := os.LookupEnv("DNS_SERVER")
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if !ok {
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DNS_SERVER = "1.1.1.1:53"
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} else {
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DNS_SERVER = dnsServer
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}
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Resolver = &net.Resolver{
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PreferGo: true,
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Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
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d := net.Dialer{
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Timeout: time.Millisecond * time.Duration(10000),
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}
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return d.DialContext(ctx, network, DNS_SERVER)
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},
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}
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var err error
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ourIPs, err = Resolver.LookupIP(context.Background(), "ip", PAGES_DOMAIN)
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if err != nil {
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panic(err)
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}
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}
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func PointingAtUs(domain string) (ok bool) {
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if !strings.HasSuffix(domain, ".") {
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domain += "."
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}
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if strings.HasSuffix(domain, "."+PAGES_DOMAIN_CANONICAL) {
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return true
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}
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ips, err := Resolver.LookupIP(context.Background(), "ip", domain)
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if err != nil {
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return
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}
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for _, ip := range ips {
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for _, ourIP := range ourIPs {
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if ip.Equal(ourIP) {
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ok = true
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return
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}
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}
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}
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return
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}
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func getTarget(domain string) (target string, err error) {
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if !strings.HasSuffix(domain, ".") {
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domain += "."
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}
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if strings.HasSuffix(domain, "."+PAGES_DOMAIN_CANONICAL) {
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target = strings.TrimSuffix(domain, ".")
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return
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}
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ctx := context.Background()
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txtResults, txtErr := Resolver.LookupTXT(ctx, domain)
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cnameResult, cnameErr := Resolver.LookupCNAME(ctx, domain)
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if txtErr != nil && cnameErr != nil {
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err = errors.NewErrorDNSNotConfigured()
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return
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}
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allResults := append(txtResults, cnameResult)
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for _, result := range allResults {
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result = strings.TrimSuffix(result, ".")
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if strings.HasSuffix(result, PAGES_SUBDOMAIN) {
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return result, nil
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}
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}
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err = errors.NewErrorNotPointedAtUs()
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return
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}
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