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|
package reverse
import (
"net"
"sort"
"strings"
"strconv"
"regexp"
"github.com/miekg/coredns/core/dnsserver"
"github.com/miekg/coredns/middleware"
"github.com/mholt/caddy"
)
func init() {
caddy.RegisterPlugin("reverse", caddy.Plugin{
ServerType: "dns",
Action: setupReverse,
})
}
func setupReverse(c *caddy.Controller) error {
networks, err := reverseParse(c)
if err != nil {
return middleware.Error("reverse", err)
}
dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
return Reverse{Next: next, Networks:networks}
})
return nil
}
func reverseParse(c *caddy.Controller) (networks, error) {
var err error
// normalize zones, validation is almost done by dnsserver
zones := make([]string, len(c.ServerBlockKeys))
for i, str := range c.ServerBlockKeys {
host, _, _ := net.SplitHostPort(str)
zones[i] = strings.ToLower(host)
}
networks := networks{}
for c.Next() {
if c.Val() == "reverse" {
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, c.Errf("%v needs to be an CIDR formatted Network\n", cidr)
}
cidrs = append(cidrs, ipnet)
}
if len(cidrs) == 0 {
return nil, c.ArgErr()
}
// set defaults
var (
template = "ip-" + templateNameIP + ".{zone[0]}"
ttl = 60
fall = false
)
for c.NextBlock() {
switch c.Val() {
case "hostname":
if !c.NextArg() {
return nil, c.ArgErr()
}
template = c.Val()
case "ttl":
if !c.NextArg() {
return nil, c.ArgErr()
}
ttl, err = strconv.Atoi(c.Val())
if err != nil {
return nil, err
}
case "fallthrough":
fall = true
default:
return nil, c.ArgErr()
}
}
// prepare template
// replace {zone[index]} by the listen zone/domain of this config block
for i, zone := range zones {
template = strings.Replace(template, "{zone[" + string(i + 48) + "]}", zone, 1)
}
if !strings.HasSuffix(template, ".") {
template += "."
}
// extract zone from template
templateZone := strings.SplitAfterN(template, ".", 2)
if len(templateZone) != 2 || templateZone[1] == "" {
return nil, 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
}
regex, err := regexp.Compile(
"^" + strings.Replace( // inject ip regex into template
regexp.QuoteMeta(template), // escape dots
regexp.QuoteMeta(templateNameIP),
regexIP,
1, ) + "$")
if err != nil {
// invalid regex
return nil, err
}
networks = append(networks, network{
IPnet: ipnet,
Zone: templateZone[1],
Template: template,
RegexMatchIP: regex,
TTL: uint32(ttl),
Fallthrough: fall,
})
}
}
}
// sort by cidr
sort.Sort(networks)
return networks, nil
}
|
