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Ixfr works, but needs to be refined

This commit is contained in:
Miek Gieben 2011-02-25 23:29:08 +01:00
parent 22f34ec885
commit 157062f6b0
3 changed files with 65 additions and 68 deletions
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8
_examples/axfr/axfr.go
View File

@ -10,26 +10,28 @@ import (
func main() {
var serial *int = flag.Int("serial", 0, "Perform an IXFR with the given serial")
var onesoa *bool = flag.Bool("1soa", false, "Don't print the last SOA")
zone := "tjeb.nl."
flag.Parse()
res := new(dns.Resolver)
res.FromFile("/etc/resolv.conf")
res.Servers[0] = "open.nlnetlabs.nl"
ch := make(chan dns.RR)
m := new(dns.Msg)
m.Question = make([]dns.Question, 1)
if *serial > 0 {
m.Question[0] = dns.Question{"miek.nl.", dns.TypeIXFR, dns.ClassINET}
m.Question[0] = dns.Question{zone, dns.TypeIXFR, dns.ClassINET}
soa := new(dns.RR_SOA)
soa.Hdr = dns.RR_Header{"miek.nl.", dns.TypeSOA, dns.ClassINET, 14400, 0}
soa.Hdr = dns.RR_Header{zone, dns.TypeSOA, dns.ClassINET, 14400, 0}
soa.Serial = uint32(*serial)
m.Ns = make([]dns.RR, 1)
m.Ns[0] = soa
go res.Ixfr(m, ch)
} else {
m.Question[0] = dns.Question{"miek.nl.", dns.TypeAXFR, dns.ClassINET}
m.Question[0] = dns.Question{zone, dns.TypeAXFR, dns.ClassINET}
go res.Axfr(m, ch)
}

3
_examples/mx/mx.go
View File

@ -15,9 +15,6 @@ func main() {
fmt.Printf("%s DOMAIN\n", os.Args[0])
os.Exit(1)
}
dns.Test()
m := new(dns.Msg)
m.MsgHdr.RecursionDesired = true //only set this bit
m.Question = make([]dns.Question, 1)

122
resolver.go
View File

@ -120,13 +120,22 @@ func (res *Resolver) Ixfr(q *Msg, m chan RR) {
return
}
const (
FIRST = iota
SECOND
LAST
)
const (
FIRST = iota
SECOND
LAST
)
defer close(m)
tAdd := new(RR_TXT)
tAdd.Hdr = RR_Header{Name: "miek.nl", Rrtype: TypeTXT, Class: ClassINET, Ttl: 3600}
tAdd.Txt = "Add"
tRem := new(RR_TXT)
tRem.Hdr = RR_Header{Name: "miek.nl", Rrtype: TypeTXT, Class: ClassINET, Ttl: 3600}
tRem.Txt = "Rem"
defer close(m)
Server:
for i := 0; i < len(res.Servers); i++ {
server := res.Servers[i] + ":" + port
@ -136,10 +145,10 @@ Server:
continue Server
}
state := FIRST
var serial uint32 // The first serial seen is the current server serial
var _ = serial
var serial uint32 // The first serial seen is the current server serial
var _ = serial
defer c.Close()
defer c.Close()
for {
if state == FIRST {
in, cerr = exchangeTCP(c, sending, res, true)
@ -154,47 +163,51 @@ Server:
continue Server
}
if in.Id != q.Id {
// Query ID mismatch
c.Close()
// Query ID mismatch
c.Close()
return
}
if state == FIRST {
// A single SOA RR signals "no changes"
if len(in.Answer) == 1 && checkAxfrSOA(in, true) {
c.Close()
return
}
// A single SOA RR signals "no changes"
if len(in.Answer) == 1 && checkAxfrSOA(in, true) {
//sendFromMsg(in, m) // Do you need to send 1 reply?
c.Close()
return
}
// But still check if the returned answer is ok
// But still check if the returned answer is ok
if !checkAxfrSOA(in, true) {
c.Close()
continue Server
}
// This serial is important
serial = in.Answer[0].(*RR_SOA).Serial
sendFromMsg(in, m)
// This serial is important
serial = in.Answer[0].(*RR_SOA).Serial
//sendFromMsg(in, m)
state = SECOND
}
// Now we need to check each message for SOA records, to see what we need to do
// Now we need to check each message for SOA records, to see what we need to do
if state != FIRST {
// If the last record in the IXFR contains the servers' SOA
// we should quit
// for _, r := range in.Answer {
// }
if !checkAxfrSOA(in, false) {
// Soa record not the last one
sendFromMsg(in, m)
continue
} else{
sendFromMsg(in, m)
return
}
// If the last record in the IXFR contains the servers' SOA
// we should quit
for k, r := range in.Answer {
if r.Header().Rrtype == TypeSOA {
se := r.(*RR_SOA).Serial
switch {
case se == serial:
if k == len(in.Answer)-1 {
// last rr is SOA with correct serial
m <- r
return
}
m <- tAdd
case se != serial:
m <- tRem
}
}
m <- r
}
}
}
panic("not reached")
@ -229,7 +242,7 @@ func (res *Resolver) Axfr(q *Msg, m chan RR) {
return
}
defer close(m)
defer close(m)
Server:
for i := 0; i < len(res.Servers); i++ {
server := res.Servers[i] + ":" + port
@ -239,7 +252,7 @@ Server:
continue Server
}
first := true
defer c.Close() // TODO(mg): if not open?
defer c.Close() // TODO(mg): if not open?
for {
if first {
in, cerr = exchangeTCP(c, sending, res, true)
@ -250,17 +263,17 @@ Server:
if cerr != nil {
// Failed to send, try the next
err = cerr
c.Close()
c.Close()
continue Server
}
if in.Id != q.Id {
c.Close()
c.Close()
return
}
if first {
if !checkAxfrSOA(in, true) {
c.Close()
c.Close()
continue Server
}
sendFromMsg(in, m)
@ -270,10 +283,10 @@ Server:
if !first {
if !checkAxfrSOA(in, false) {
// Soa record not the last one
sendFromMsg(in, m)
sendFromMsg(in, m)
continue
} else {
sendFromMsg(in, m)
sendFromMsg(in, m)
return
}
}
@ -456,24 +469,9 @@ func checkAxfrSOA(in *Msg, first bool) bool {
return false
}
// Same as Axfr one, but now also check the serial
func checkIxfrSOA(in *Msg, first bool, serial uint32) bool {
if len(in.Answer) > 0 {
if first {
return in.Answer[0].Header().Rrtype == TypeSOA &&
in.Answer[0].(*RR_SOA).Serial == serial
} else {
return in.Answer[len(in.Answer)-1].Header().Rrtype == TypeSOA &&
in.Answer[len(in.Answer)-1].(*RR_SOA).Serial == serial
}
}
return false
}
// Send the answer section to the channel
func sendFromMsg(in *Msg, c chan RR) {
for _, r := range in.Answer {
c <- r
}
for _, r := range in.Answer {
c <- r
}
}