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package plugin
import (
"fmt"
"net"
"runtime"
"strconv"
"strings"
"github.com/coredns/coredns/plugin/pkg/cidr"
"github.com/coredns/coredns/plugin/pkg/log"
"github.com/coredns/coredns/plugin/pkg/parse"
"github.com/miekg/dns"
)
// See core/dnsserver/address.go - we should unify these two impls.
// Zones represents a lists of zone names.
type Zones []string
// Matches checks if qname is a subdomain of any of the zones in z. The match
// will return the most specific zones that matches. The empty string
// signals a not found condition.
func (z Zones) Matches(qname string) string {
zone := ""
for _, zname := range z {
if dns.IsSubDomain(zname, qname) {
// We want the *longest* matching zone, otherwise we may end up in a parent
if len(zname) > len(zone) {
zone = zname
}
}
}
return zone
}
// Normalize fully qualifies all zones in z. The zones in Z must be domain names, without
// a port or protocol prefix.
func (z Zones) Normalize() {
for i := range z {
z[i] = Name(z[i]).Normalize()
}
}
// Name represents a domain name.
type Name string
// Matches checks to see if other is a subdomain (or the same domain) of n.
// This method assures that names can be easily and consistently matched.
func (n Name) Matches(child string) bool {
if dns.Name(n) == dns.Name(child) {
return true
}
return dns.IsSubDomain(string(n), child)
}
// Normalize lowercases and makes n fully qualified.
func (n Name) Normalize() string { return strings.ToLower(dns.Fqdn(string(n))) }
type (
// Host represents a host from the Corefile, may contain port.
Host string
)
// Normalize will return the host portion of host, stripping
// of any port or transport. The host will also be fully qualified and lowercased.
// An empty string is returned on failure
// Deprecated: use OriginsFromArgsOrServerBlock or NormalizeExact
func (h Host) Normalize() string {
var caller string
if _, file, line, ok := runtime.Caller(1); ok {
caller = fmt.Sprintf("(%v line %d) ", file, line)
}
log.Warning("An external plugin " + caller + "is using the deprecated function Normalize. " +
"This will be removed in a future versions of CoreDNS. The plugin should be updated to use " +
"OriginsFromArgsOrServerBlock or NormalizeExact instead.")
s := string(h)
_, s = parse.Transport(s)
// The error can be ignored here, because this function is called after the corefile has already been vetted.
hosts, _, err := SplitHostPort(s)
if err != nil {
return ""
}
return Name(hosts[0]).Normalize()
}
// MustNormalize will return the host portion of host, stripping
// of any port or transport. The host will also be fully qualified and lowercased.
// An error is returned on error
// Deprecated: use OriginsFromArgsOrServerBlock or NormalizeExact
func (h Host) MustNormalize() (string, error) {
var caller string
if _, file, line, ok := runtime.Caller(1); ok {
caller = fmt.Sprintf("(%v line %d) ", file, line)
}
log.Warning("An external plugin " + caller + "is using the deprecated function MustNormalize. " +
"This will be removed in a future versions of CoreDNS. The plugin should be updated to use " +
"OriginsFromArgsOrServerBlock or NormalizeExact instead.")
s := string(h)
_, s = parse.Transport(s)
// The error can be ignored here, because this function is called after the corefile has already been vetted.
hosts, _, err := SplitHostPort(s)
if err != nil {
return "", err
}
return Name(hosts[0]).Normalize(), nil
}
// NormalizeExact will return the host portion of host, stripping
// of any port or transport. The host will also be fully qualified and lowercased.
// An empty slice is returned on failure
func (h Host) NormalizeExact() []string {
// The error can be ignored here, because this function should only be called after the corefile has already been vetted.
s := string(h)
_, s = parse.Transport(s)
hosts, _, err := SplitHostPort(s)
if err != nil {
return nil
}
for i := range hosts {
hosts[i] = Name(hosts[i]).Normalize()
}
return hosts
}
// SplitHostPort splits s up in a host(s) and port portion, taking reverse address notation into account.
// String the string s should *not* be prefixed with any protocols, i.e. dns://. SplitHostPort can return
// multiple hosts when a reverse notation on a non-octet boundary is given.
func SplitHostPort(s string) (hosts []string, port string, err error) {
// If there is: :[0-9]+ on the end we assume this is the port. This works for (ascii) domain
// names and our reverse syntax, which always needs a /mask *before* the port.
// So from the back, find first colon, and then check if it's a number.
colon := strings.LastIndex(s, ":")
if colon == len(s)-1 {
return nil, "", fmt.Errorf("expecting data after last colon: %q", s)
}
if colon != -1 {
if p, err := strconv.Atoi(s[colon+1:]); err == nil {
port = strconv.Itoa(p)
s = s[:colon]
}
}
// TODO(miek): this should take escaping into account.
if len(s) > 255 {
return nil, "", fmt.Errorf("specified zone is too long: %d > 255", len(s))
}
if _, ok := dns.IsDomainName(s); !ok {
return nil, "", fmt.Errorf("zone is not a valid domain name: %s", s)
}
// Check if it parses as a reverse zone, if so we use that. Must be fully specified IP and mask.
_, n, err := net.ParseCIDR(s)
if err != nil {
return []string{s}, port, nil
}
if s[0] == ':' || (s[0] == '0' && strings.Contains(s, ":")) {
return nil, "", fmt.Errorf("invalid CIDR %s", s)
}
// now check if multiple hosts must be returned.
nets := cidr.Split(n)
hosts = cidr.Reverse(nets)
return hosts, port, nil
}
// OriginsFromArgsOrServerBlock returns the normalized args if that slice
// is not empty, otherwise the serverblock slice is returned (in a newly copied slice).
func OriginsFromArgsOrServerBlock(args, serverblock []string) []string {
if len(args) == 0 {
s := make([]string, len(serverblock))
copy(s, serverblock)
for i := range s {
s[i] = Host(s[i]).NormalizeExact()[0] // expansion of these already happened in dnsserver/register.go
}
return s
}
s := []string{}
for i := range args {
sx := Host(args[i]).NormalizeExact()
if len(sx) == 0 {
continue // silently ignores errors.
}
s = append(s, sx...)
}
return s
}
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