feat: Allow usage for top-level domains
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This commit is contained in:
PapaTutuWawa 2024-01-13 17:30:55 +01:00
parent 9b971daf28
commit f264bd5604
2 changed files with 77 additions and 1 deletions

View File

@ -2,6 +2,7 @@ package dns
import ( import (
"net" "net"
"errors"
"strings" "strings"
"time" "time"
@ -15,6 +16,10 @@ const (
// The key that the TXT record will have to start with, e.g. // The key that the TXT record will have to start with, e.g.
// "repo=some-random-repo". // "repo=some-random-repo".
TxtRepoKey = "repo=" TxtRepoKey = "repo="
TxtCNAMERecord = "_rio-cname."
TxtCNAMEKey = "cname="
) )
var ( var (
@ -61,14 +66,53 @@ func LookupCNAME(domain string) (string, error) {
return cname.(string), nil return cname.(string), nil
} }
cname, err := lookupCNAME(domain)
if err == nil {
cnameCache.Set(domain, cname, cache.DefaultExpiration)
return cname.(string), nil
}
altCname, err := lookupCNAMETxt(domain)
if err == nil {
cnameCache.Set(domain, altCname, cache.DefaultExpiration)
return altCname, nil
}
return "", err
}
// Lookup the CNAME by trying to find a CNAME RR. Contrary to net.LookupCNAME,
// this method fails if we find no CNAME RR.
func lookupCNAME(domain string) (string, error) {
query, err := net.LookupCNAME(domain) query, err := net.LookupCNAME(domain)
if err == nil { if err == nil {
if query[len(query)-1] == '.' { if query[len(query)-1] == '.' {
query = query[:len(query)-1] query = query[:len(query)-1]
} }
cnameCache.Set(domain, query, cache.DefaultExpiration)
// Fail if we have no CNAME RR.
if query == domain {
return "", errors.New("CNAME is equal to domain")
}
return query, nil return query, nil
} }
return "", err return "", err
} }
// Performs an alternative CNAME lookup by looking for a special TXT record.
func lookupCNAMETxt(domain string) (string, error) {
txts, err := net.LookupTXT(TxtCNAMERecord+domain)
if err == nil {
for _, txt := range txts {
if !strings.HasPrefix(txt, TxtCNAMEKey) {
continue
}
return strings.TrimPrefix(txt, TxtCNAMEKey), nil
}
}
return "", err
}

32
internal/dns/dns_test.go Normal file
View File

@ -0,0 +1,32 @@
package dns
import "testing"
func cleanCache() {
cnameCache.Flush()
txtRepoCache.Flush()
}
func TestAltCNAME(t *testing.T) {
defer cleanCache()
res, err := lookupCNAMETxt("moxxy.org")
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if res != "moxxy.pages.polynom.me" {
t.Fatalf("Unexpected alt CNAME: %s", res)
}
}
func TestLookupCNAMEWithAlt(t *testing.T) {
defer cleanCache()
res, err := LookupCNAME("moxxy.org")
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if res != "moxxy.pages.polynom.me" {
t.Fatalf("Unexpected alt CNAME: %s", res)
}
}