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|
package reverse
import (
"net"
"regexp"
"sort"
"strconv"
"strings"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/pkg/fall"
"github.com/mholt/caddy"
)
func init() {
caddy.RegisterPlugin("reverse", caddy.Plugin{
ServerType: "dns",
Action: setupReverse,
})
}
func setupReverse(c *caddy.Controller) error {
networks, fall, err := reverseParse(c)
if err != nil {
return plugin.Error("reverse", err)
}
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
return Reverse{Next: next, Networks: networks, Fall: fall}
})
return nil
}
func reverseParse(c *caddy.Controller) (nets networks, f *fall.F, err error) {
zones := make([]string, len(c.ServerBlockKeys))
wildcard := false
// We copy from the serverblock, these contains Hosts.
for i, str := range c.ServerBlockKeys {
zones[i] = plugin.Host(str).Normalize()
}
for c.Next() {
var cidrs []*net.IPNet
// parse all networks
for _, cidr := range c.RemainingArgs() {
if cidr == "{" {
break
}
_, ipnet, err := net.ParseCIDR(cidr)
if err != nil {
return nil, f, c.Errf("network needs to be CIDR formatted: %q\n", cidr)
}
cidrs = append(cidrs, ipnet)
}
if len(cidrs) == 0 {
return nil, f, c.ArgErr()
}
// set defaults
var (
template = "ip-" + templateNameIP + ".{zone[1]}"
ttl = 60
)
for c.NextBlock() {
switch c.Val() {
case "hostname":
if !c.NextArg() {
return nil, f, c.ArgErr()
}
template = c.Val()
case "ttl":
if !c.NextArg() {
return nil, f, c.ArgErr()
}
ttl, err = strconv.Atoi(c.Val())
if err != nil {
return nil, f, err
}
case "wildcard":
wildcard = true
case "fallthrough":
f = fall.New()
f.SetZones(c.RemainingArgs())
default:
return nil, f, c.ArgErr()
}
}
// prepare template
// replace {zone[index]} by the listen zone/domain of this config block
for i, zone := range zones {
// TODO: we should be smarter about actually replacing this. This works, but silently allows "zone[-1]"
// for instance.
template = strings.Replace(template, "{zone["+strconv.Itoa(i+1)+"]}", zone, 1)
}
if !strings.HasSuffix(template, ".") {
template += "."
}
// extract zone from template
templateZone := strings.SplitAfterN(template, ".", 2)
if len(templateZone) != 2 || templateZone[1] == "" {
return nil, f, c.Errf("cannot find domain in template '%v'", template)
}
// Create for each configured network in this stanza
for _, ipnet := range cidrs {
// precompile regex for hostname to ip matching
regexIP := regexMatchV4
if ipnet.IP.To4() == nil {
regexIP = regexMatchV6
}
prefix := "^"
if wildcard {
prefix += ".*"
}
regex, err := regexp.Compile(
prefix + strings.Replace( // inject ip regex into template
regexp.QuoteMeta(template), // escape dots
regexp.QuoteMeta(templateNameIP),
regexIP,
1) + "$")
if err != nil {
return nil, f, err
}
nets = append(nets, network{
IPnet: ipnet,
Zone: templateZone[1],
Template: template,
RegexMatchIP: regex,
TTL: uint32(ttl),
})
}
}
// sort by cidr
sort.Sort(nets)
return nets, f, nil
}
|
