From 3f48a4190de49998ffc8dc9fa7f7c607c97528b6 Mon Sep 17 00:00:00 2001 From: m5r Date: Wed, 17 Jul 2024 23:21:54 +0200 Subject: [PATCH] fix invalid records & automatically split long TXT records into chunks of up to 255 characters --- xip/xip.go | 127 ++++++++++++++++++++++++++++++++++------------------- 1 file changed, 81 insertions(+), 46 deletions(-) diff --git a/xip/xip.go b/xip/xip.go index 68c1aa3..651b9a6 100644 --- a/xip/xip.go +++ b/xip/xip.go @@ -20,7 +20,7 @@ type Xip struct { type HardcodedRecord struct { A []*dns.A AAAA []*dns.AAAA - TXT *dns.TXT + TXT []string // *dns.TXT MX []*dns.MX CNAME []*dns.CNAME SRV *dns.SRV @@ -58,44 +58,40 @@ var ( // {A: net.IPv4(66, 241, 125, 48)}, {A: net.IPv4(137, 66, 40, 11)}, // fly.io edge-only ip address }, - TXT: &dns.TXT{ - Txt: []string{ - "sl-verification=frudknyqpqlpgzbglkqnsmorfcvxrf", - "v=spf1 include:capsulecorp.dev ~all", - }, - }, + TXT: []string{"v=spf1 include:capsulecorp.dev ~all"}, MX: []*dns.MX{ {Preference: 10, Mx: "email.capsulecorp.dev."}, }, }, "autodiscover.local-ip.sh.": { CNAME: []*dns.CNAME{ - {Target: "email.capsulecorp.dev"}, + {Target: "email.capsulecorp.dev."}, }, }, "_autodiscover._tcp.local-ip.sh.": { SRV: &dns.SRV{ - Target: "email.capsulecorp.dev 443", + Priority: 0, + Weight: 0, + Port: 443, + Target: "email.capsulecorp.dev.", }, }, "autoconfig.local-ip.sh.": { CNAME: []*dns.CNAME{ - {Target: "email.capsulecorp.dev"}, + {Target: "email.capsulecorp.dev."}, }, }, "_dmarc.local-ip.sh.": { - TXT: &dns.TXT{ - Txt: []string{"v=DMARC1; p=none; rua=mailto:postmaster@local-ip.sh; ruf=mailto:admin@local-ip.sh"}, - }, + TXT: []string{"v=DMARC1; p=none; rua=mailto:postmaster@local-ip.sh; ruf=mailto:admin@local-ip.sh"}, }, "dkim._domainkey.local-ip.sh.": { - TXT: &dns.TXT{ - Txt: []string{"v=DKIM1;k=rsa;t=s;s=email;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsMW6NFo34qzKRPbzK41GwbWncB8IDg1i2eA2VWznIVDmTzzsqILaBOGv2xokVpzZm0QRF9wSbeVUmvwEeQ7Z6wkfMjawenDEc3XxsNSvQUVBP6LU/xcm1zsR8wtD8r5J+Jm45pNFaateiM/kb/Eypp2ntdtd8CPsEgCEDpNb62LWdy0yzRdZ/M/fNn51UMN8hVFp4YfZngAt3bQwa6kPtgvTeqEbpNf5xanpDysNJt2S8zfqJMVGvnr8JaJiTv7ZlKMMp94aC5Ndcir1WbMyfmgSnGgemuCTVMWDGPJnXDi+8BQMH1b1hmTpWDiVdVlehyyWx5AfPrsWG9cEuDIfXwIDAQAB"}, + TXT: []string{ + "v=DKIM1;k=rsa;t=s;s=email;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsMW6NFo34qzKRPbzK41GwbWncB8IDg1i2eA2VWznIVDmTzzsqILaBOGv2xokVpzZm0QRF9wSbeVUmvwEeQ7Z6wkfMjawenDEc3XxsNSvQUVBP6LU/xcm1zsR8wtD8r5J+Jm45pNFaateiM/kb/Eypp2ntdtd8CPsEgCEDpNb62LWdy0yzRdZ/M/fNn51UMN8hVFp4YfZngAt3bQwa6kPtgvTeqEbpNf5xanpDysNJt2S8zfqJMVGvnr8JaJiTv7ZlKMMp94aC5Ndcir1WbMyfmgSnGgemuCTVMWDGPJnXDi+8BQMH1b1hmTpWDiVdVlehyyWx5AfPrsWG9cEuDIfXwIDAQAB", }, }, "_acme-challenge.local-ip.sh.": { // will be filled in later when requesting the wildcard certificate - TXT: &dns.TXT{}, + TXT: []string{}, }, } ) @@ -108,9 +104,7 @@ func (xip *Xip) SetTXTRecord(fqdn string, value string) { } if records, ok := hardcodedRecords[fqdn]; ok { - records.TXT = &dns.TXT{ - Txt: []string{value}, - } + records.TXT = []string{value} hardcodedRecords["_acme-challenge.local-ip.sh."] = records } } @@ -123,19 +117,20 @@ func (xip *Xip) UnsetTXTRecord(fqdn string) { } if records, ok := hardcodedRecords[fqdn]; ok { - records.TXT = nil + records.TXT = []string{} hardcodedRecords["_acme-challenge.local-ip.sh."] = records } } func (xip *Xip) fqdnToA(fqdn string) []*dns.A { - if hardcodedRecords[strings.ToLower(fqdn)].A != nil { + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].A != nil { var records []*dns.A - for _, record := range hardcodedRecords[strings.ToLower(fqdn)].A { + for _, record := range hardcodedRecords[normalizedFqdn].A { records = append(records, &dns.A{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeA, Class: dns.ClassINET, @@ -158,7 +153,7 @@ func (xip *Xip) fqdnToA(fqdn string) []*dns.A { return []*dns.A{{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeA, Class: dns.ClassINET, @@ -193,15 +188,16 @@ func (xip *Xip) handleA(question dns.Question, message *dns.Msg) { func (xip *Xip) handleAAAA(question dns.Question, message *dns.Msg) { fqdn := question.Name - if hardcodedRecords[strings.ToLower(fqdn)].AAAA == nil { + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].AAAA == nil { xip.answerWithAuthority(question, message) return } - for _, record := range hardcodedRecords[strings.ToLower(fqdn)].AAAA { + for _, record := range hardcodedRecords[normalizedFqdn].AAAA { message.Answer = append(message.Answer, &dns.AAAA{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, @@ -218,7 +214,7 @@ func (xip *Xip) handleNS(question dns.Question, message *dns.Msg) { for _, ns := range xip.nameServers { nameServers = append(nameServers, &dns.NS{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeNS, Class: dns.ClassINET, @@ -238,35 +234,46 @@ func (xip *Xip) handleNS(question dns.Question, message *dns.Msg) { } } +func chunkBy(str string, chunkSize int) (chunks []string) { + for chunkSize < len(str) { + str, chunks = str[chunkSize:], append(chunks, str[0:chunkSize]) + } + return append(chunks, str) +} + func (xip *Xip) handleTXT(question dns.Question, message *dns.Msg) { fqdn := question.Name - if hardcodedRecords[strings.ToLower(fqdn)].TXT == nil { + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].TXT == nil { xip.answerWithAuthority(question, message) return } - message.Answer = append(message.Answer, &dns.TXT{ - Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), - Name: fqdn, - Rrtype: dns.TypeTXT, - Class: dns.ClassINET, - }, - Txt: hardcodedRecords[strings.ToLower(fqdn)].TXT.Txt, - }) + for _, record := range hardcodedRecords[normalizedFqdn].TXT { + message.Answer = append(message.Answer, &dns.TXT{ + Hdr: dns.RR_Header{ + Ttl: uint32((time.Minute * 5).Seconds()), + Name: fqdn, + Rrtype: dns.TypeTXT, + Class: dns.ClassINET, + }, + Txt: chunkBy(record, 255), + }) + } } func (xip *Xip) handleMX(question dns.Question, message *dns.Msg) { fqdn := question.Name - if hardcodedRecords[strings.ToLower(fqdn)].MX == nil { + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].MX == nil { xip.answerWithAuthority(question, message) return } - for _, record := range hardcodedRecords[strings.ToLower(fqdn)].MX { + for _, record := range hardcodedRecords[normalizedFqdn].MX { message.Answer = append(message.Answer, &dns.MX{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeMX, Class: dns.ClassINET, @@ -279,15 +286,16 @@ func (xip *Xip) handleMX(question dns.Question, message *dns.Msg) { func (xip *Xip) handleCNAME(question dns.Question, message *dns.Msg) { fqdn := question.Name - if hardcodedRecords[strings.ToLower(fqdn)].CNAME == nil { + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].CNAME == nil { xip.answerWithAuthority(question, message) return } - for _, record := range hardcodedRecords[strings.ToLower(fqdn)].CNAME { + for _, record := range hardcodedRecords[normalizedFqdn].CNAME { message.Answer = append(message.Answer, &dns.CNAME{ Hdr: dns.RR_Header{ - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Name: fqdn, Rrtype: dns.TypeCNAME, Class: dns.ClassINET, @@ -297,6 +305,28 @@ func (xip *Xip) handleCNAME(question dns.Question, message *dns.Msg) { } } +func (xip *Xip) handleSRV(question dns.Question, message *dns.Msg) { + fqdn := question.Name + normalizedFqdn := strings.ToLower(fqdn) + if hardcodedRecords[normalizedFqdn].SRV == nil { + xip.answerWithAuthority(question, message) + return + } + + message.Answer = append(message.Answer, &dns.SRV{ + Hdr: dns.RR_Header{ + Ttl: uint32((time.Minute * 5).Seconds()), + Name: fqdn, + Rrtype: dns.TypeSRV, + Class: dns.ClassINET, + }, + Priority: hardcodedRecords[normalizedFqdn].SRV.Priority, + Weight: hardcodedRecords[normalizedFqdn].SRV.Weight, + Port: hardcodedRecords[normalizedFqdn].SRV.Port, + Target: hardcodedRecords[normalizedFqdn].SRV.Target, + }) +} + func (xip *Xip) handleSOA(question dns.Question, message *dns.Msg) { message.Answer = append(message.Answer, xip.soaRecord(question)) } @@ -307,7 +337,7 @@ func (xip *Xip) soaRecord(question dns.Question) *dns.SOA { Name: question.Name, Rrtype: dns.TypeSOA, Class: dns.ClassINET, - Ttl: uint32((time.Hour * 24 * 7).Seconds()), + Ttl: uint32((time.Minute * 5).Seconds()), Rdlength: 0, } soa.Ns = "ns1.local-ip.sh." @@ -336,6 +366,8 @@ func (xip *Xip) handleQuery(message *dns.Msg) { xip.handleMX(question, message) case dns.TypeCNAME: xip.handleCNAME(question, message) + case dns.TypeSRV: + xip.handleSRV(question, message) case dns.TypeSOA: xip.handleSOA(question, message) default: @@ -359,7 +391,10 @@ func (xip *Xip) handleDnsRequest(response dns.ResponseWriter, request *dns.Msg) message.MsgHdr.Rcode = dns.RcodeRefused } - response.WriteMsg(message) + error := response.WriteMsg(message) + if error != nil { + log.Printf("Error writing answer \"%s\": %s\n", message.String(), error.Error()) + } }() }