From 99568644d14077f1a449225562718f4c55e63def Mon Sep 17 00:00:00 2001 From: Niklas Date: Mon, 21 Dec 2020 22:43:07 +0100 Subject: [PATCH] initial commit --- config.yml | 17 +++++ coolDns.go | 205 +++++++++++++++++++++++++++++++++++++++++++++++++++ go.mod | 8 ++ go.sum | 23 ++++++ zonefile.txt | 18 +++++ 5 files changed, 271 insertions(+) create mode 100644 config.yml create mode 100644 coolDns.go create mode 100644 go.mod create mode 100644 go.sum create mode 100644 zonefile.txt diff --git a/config.yml b/config.yml new file mode 100644 index 0000000..b2c5106 --- /dev/null +++ b/config.yml @@ -0,0 +1,17 @@ +zones: +- zone: example.com. + file: zonefile.txt +- zone: example.com. + file: zonefile.txt + acl: + - vpn + +acl: +- name: vpn + range: 10.0.0.0/24 + +forward: + alc: + - vpn + + diff --git a/coolDns.go b/coolDns.go new file mode 100644 index 0000000..a9461df --- /dev/null +++ b/coolDns.go @@ -0,0 +1,205 @@ +package main + +import ( + "io/ioutil" + "log" + "os" + "os/signal" + "strconv" + "syscall" + + "github.com/miekg/dns" + "gopkg.in/yaml.v3" +) + +type zone struct { + zone string + rr rrMap + acl []string +} + +type rrMap map[uint16]map[string][]dns.RR + +type config struct { + Zones []configZone `yaml:"zones"` + ACL []configACL `yaml:"acl"` + Forward configForward `yaml:"forward"` +} + +type configForward struct { + ACL []string `yaml:"acl"` +} + +type configACL struct { + Name string `yaml:"name"` + IPRange string `yaml:"range"` +} + +type configZone struct { + Zone string `yaml:"zone"` + File string `yaml:"file"` + ACL []string `yaml:"acl"` +} + +func loadConfig() (*config, error) { + file, err := ioutil.ReadFile("config.yml") + if err != nil { + return nil, err + } + + var loadedConfig config + + err = yaml.Unmarshal(file, &loadedConfig) + if err != nil { + return nil, err + } + + return &loadedConfig, nil +} + +func loadZones(configZones []configZone) ([]zone, error) { + zones := make([]zone, 0) + for _, z := range configZones { + rrs, err := loadZonefile(z.File) + if err != nil { + return nil, err + } + zones = append(zones, zone{ + zone: z.Zone, + rr: createRRMap(rrs), + }) + log.Printf("Loaded zone %s\n", z.Zone) + } + + return zones, nil +} + +func createRRMap(rrs []dns.RR) rrMap { + rrMap := make(rrMap) + for _, rr := range rrs { + if rrMap[rr.Header().Rrtype] == nil { + rrMap[rr.Header().Rrtype] = make(map[string][]dns.RR) + } + + if rrMap[rr.Header().Rrtype][rr.Header().Name] == nil { + rrMap[rr.Header().Rrtype][rr.Header().Name] = make([]dns.RR, 0) + } + rrMap[rr.Header().Rrtype][rr.Header().Name] = append(rrMap[rr.Header().Rrtype][rr.Header().Name], rr) + } + + return rrMap +} + +func loadZonefile(filepath string) ([]dns.RR, error) { + file, err := os.Open(filepath) + + if err != nil { + return nil, err + } + + parser := dns.NewZoneParser(file, "", "") + + var rrs = make([]dns.RR, 0) + + for rr, ok := parser.Next(); ok; rr, ok = parser.Next() { + rrs = append(rrs, rr) + } + + if err := parser.Err(); err != nil { + log.Println(err) + } + + return rrs, nil +} + +func createServer(zones []zone, config config) *dns.ServeMux { + srv := dns.NewServeMux() + + for _, z := range zones { + srv.HandleFunc(z.zone, func(w dns.ResponseWriter, r *dns.Msg) { + m := new(dns.Msg) + m.SetReply(r) + m.Authoritative = true + + // maybe only support one question per query like most servers do it ??? + for _, q := range r.Question { + rr := z.rr[q.Qtype] + + m.Answer = append(m.Answer, rr[q.Name]...) + + // Handle extras + switch q.Qtype { + case dns.TypeMX: + // Resolve MX domains + for _, mxRR := range rr[q.Name] { + if t, ok := mxRR.(*dns.MX); ok { + m.Extra = append(m.Extra, z.rr[dns.TypeA][t.Mx]...) + m.Extra = append(m.Extra, z.rr[dns.TypeAAAA][t.Mx]...) + } + } + case dns.TypeA, dns.TypeAAAA: + if len(m.Answer) == 0 { + // no A or AAAA found. Look for CNAME + m.Answer = append(m.Answer, z.rr[dns.TypeCNAME][q.Name]...) + if len(m.Answer) != 0 { + // Resolve CNAME + for _, nameRR := range m.Answer { + if t, ok := nameRR.(*dns.CNAME); ok { + m.Answer = append(m.Answer, z.rr[q.Qtype][t.Target]...) + } + } + } + } + case dns.TypeNS: + // Resove NS records + for _, nsRR := range rr[q.Name] { + if t, ok := nsRR.(*dns.NS); ok { + m.Extra = append(m.Extra, z.rr[dns.TypeA][t.Ns]...) + m.Extra = append(m.Extra, z.rr[dns.TypeAAAA][t.Ns]...) + } + } + } + } + + w.WriteMsg(m) + }) + } + + return srv +} + +func listenAndServer(server *dns.ServeMux) { + go func() { + if err := dns.ListenAndServe(":"+strconv.Itoa(8053), "udp", server); err != nil { + log.Fatalf("Failed to set udp listener %s\n", err.Error()) + } + }() + + go func() { + if err := dns.ListenAndServe(":"+strconv.Itoa(8053), "tcp", server); err != nil { + log.Fatalf("Failed to set tcp listener %s\n", err.Error()) + } + }() + + sig := make(chan os.Signal) + signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM) + s := <-sig + log.Printf("Signal (%v) received, stopping\n", s) + os.Exit(0) +} + +func main() { + config, err := loadConfig() + if err != nil { + log.Fatalf("Failed to load config: %s", err.Error()) + } + + zones, err := loadZones(config.Zones) + if err != nil { + log.Fatalf("Failed to load zones: %s", err.Error()) + } + + server := createServer(zones, *config) + + listenAndServer(server) +} diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..3189f29 --- /dev/null +++ b/go.mod @@ -0,0 +1,8 @@ +module git.kapelle.org/niklas/cool-dns + +go 1.15 + +require ( + github.com/miekg/dns v1.1.35 + gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 +) diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..04414e2 --- /dev/null +++ b/go.sum @@ -0,0 +1,23 @@ +github.com/miekg/dns v1.1.35 h1:oTfOaDH+mZkdcgdIjH6yBajRGtIwcwcaR+rt23ZSrJs= +github.com/miekg/dns v1.1.35/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM= +golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= +golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8= +golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI= +golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg= +golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= +golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= +golang.org/x/net v0.0.0-20190923162816-aa69164e4478 h1:l5EDrHhldLYb3ZRHDUhXF7Om7MvYXnkV9/iQNo1lX6g= +golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= +golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU= +golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= +golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= +golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= +golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe h1:6fAMxZRR6sl1Uq8U61gxU+kPTs2tR8uOySCbBP7BN/M= +golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= +golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= +golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28= +golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= +gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM= +gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= +gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 h1:tQIYjPdBoyREyB9XMu+nnTclpTYkz2zFM+lzLJFO4gQ= +gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/zonefile.txt b/zonefile.txt new file mode 100644 index 0000000..600b05f --- /dev/null +++ b/zonefile.txt @@ -0,0 +1,18 @@ +$ORIGIN example.com. ; designates the start of this zone file in the namespace +$TTL 3600 ; default expiration time (in seconds) of all RRs without their own TTL value +example.com. IN SOA ns.example.com. username.example.com. ( 2020091025 7200 3600 1209600 3600 ) +example.com. IN NS ns ; ns.example.com is a nameserver for example.com +example.com. IN NS ns.somewhere.example. ; ns.somewhere.example is a backup nameserver for example.com +example.com. IN MX 10 mail.example.com. ; mail.example.com is the mailserver for example.com +@ IN MX 20 mail2.example.com. ; equivalent to above line, "@" represents zone origin +@ IN MX 50 mail3 ; equivalent to above line, but using a relative host name +example.com. IN A 192.0.2.1 ; IPv4 address for example.com +example.com. IN A 192.0.3.1 ; IPv4 address for example.com + IN AAAA 2001:db8:10::1 ; IPv6 address for example.com +ns IN A 192.0.2.2 ; IPv4 address for ns.example.com + IN AAAA 2001:db8:10::2 ; IPv6 address for ns.example.com +www IN CNAME example.com. ; www.example.com is an alias for example.com +wwwtest IN CNAME www ; wwwtest.example.com is another alias for www.example.com +mail IN A 192.0.2.3 ; IPv4 address for mail.example.com +mail2 IN A 192.0.2.4 ; IPv4 address for mail2.example.com +mail3 IN A 192.0.2.5 ; IPv4 address for mail3.example.com