TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

middleware/reverse: random updates (#516)

Browse source 
* middleware/reverse: random updates

Make the documentation somewhat shorter (and hopefully clearer in the
process). Also to be on-par with the *auto* middleware, start counting
the referenced zones from 1 (instead of 0).
Some variable cleanups and use the NextOrFailure in the ServeDNS
function.

* More TODOs
This commit is contained in:
Miek Gieben 2017-02-10 12:48:51 +00:00 • committed by GitHub
parent 87a39a6353
commit 3e196a6d57
5 changed files with 123 additions and 154 deletions
Download patch file Download diff file Expand all files Collapse all files

57
middleware/reverse/network.go
View file

@ -1,47 +1,46 @@
package reverse
import (
"bytes"
"net"
"regexp"
"bytes"
"strings"
)
type network struct {
IPnet *net.IPNet
Zone string // forward lookup zone
Zone string // forward lookup zone
Template string
TTL uint32
RegexMatchIP *regexp.Regexp
Fallthrough bool
}
// TODO: we might want to get rid of these regexes.
const hexDigit = "0123456789abcdef"
const templateNameIP = "{ip}"
const regexMatchV4 = "((?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\-){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))"
const regexMatchV6 = "([0-9a-fA-F]{32})"
// For forward lookup
// converts the hostname back to an ip, based on the template
// returns nil if there is no ip found
// hostnameToIP converts the hostname back to an ip, based on the template
// returns nil if there is no IP found.
func (network *network) hostnameToIP(rname string) net.IP {
var matchedIP net.IP
// use precompiled regex by setup
match := network.RegexMatchIP.FindStringSubmatch(rname)
// regex did not matched
if (len(match) != 2) {
if len(match) != 2 {
return nil
}
if network.IPnet.IP.To4() != nil {
matchedIP = net.ParseIP(strings.Replace(match[1], "-", ".", 4))
} else {
// TODO: can probably just allocate a []byte and use that.
var buf bytes.Buffer
// convert back to an valid ipv6 string with colons
for i := 0; i < 8 * 4; i += 4 {
buf.WriteString(match[1][i:i + 4])
if (i < 28) {
for i := 0; i < 8*4; i += 4 {
buf.WriteString(match[1][i : i+4])
if i < 28 {
buf.WriteString(":")
}
}
@ -56,13 +55,9 @@ func (network *network) hostnameToIP(rname string) net.IP {
return matchedIP
}
// For reverse lookup
// Converts an Ip to an dns compatible hostname and injects it into the template.domain
func (network *network) ipToHostname(ip net.IP) string {
var name string
ipv4 := ip.To4()
if ipv4 != nil {
// ipToHostname converts an IP to an DNS compatible hostname and injects it into the template.domain.
func (network *network) ipToHostname(ip net.IP) (name string) {
if ipv4 := ip.To4(); ipv4 != nil {
// replace . to -
name = uitoa(ipv4[0]) + "-" +
uitoa(ipv4[1]) + "-" +
@ -71,11 +66,11 @@ func (network *network) ipToHostname(ip net.IP) string {
} else {
// assume v6
// ensure zeros are present in string
buf := make([]byte, 0, len(ip) * 4)
buf := make([]byte, 0, len(ip)*4)
for i := 0; i < len(ip); i++ {
v := ip[i]
buf = append(buf, hexDigit[v >> 4])
buf = append(buf, hexDigit[v & 0xF])
buf = append(buf, hexDigit[v>>4])
buf = append(buf, hexDigit[v&0xF])
}
name = string(buf)
}
@ -93,7 +88,7 @@ func uitoa(val uint8) string {
i := len(buf) - 1
for val >= 10 {
q := val / 10
buf[i] = byte('0' + val - q * 10)
buf[i] = byte('0' + val - q*10)
i--
val = q
}
@ -104,20 +99,12 @@ func uitoa(val uint8) string {
type networks []network
// implements the sort interface
func (slice networks) Len() int {
return len(slice)
}
func (n networks) Len() int { return len(n) }
func (n networks) Swap(i, j int) { n[i], n[j] = n[j], n[i] }
// implements the sort interface
// cidr closer to the ip wins (by netmask)
func (slice networks) Less(i, j int) bool {
isize, _ := slice[i].IPnet.Mask.Size()
jsize, _ := slice[j].IPnet.Mask.Size()
func (n networks) Less(i, j int) bool {
isize, _ := n[i].IPnet.Mask.Size()
jsize, _ := n[j].IPnet.Mask.Size()
return isize > jsize
}
// implements the sort interface
func (slice networks) Swap(i, j int) {
slice[i], slice[j] = slice[j], slice[i]
}