coredns-ldap/ldap.go
2020-06-07 23:12:18 -05:00

117 lines
3.6 KiB
Go

// Package ldap is a CoreDNS plugin that resolves A, AAAA y PTR RR from a ldap backend.
//
// It serves as a backend connector for autoritative zone data.
// Ldap is often used for bare metal inventories. This use is the main use case
// for this plugin. Other use cases might eventually be supported.
// fqdn and ip4 / ip6 information is mapped from it's repsective ldap schema and
// served as DNS records over coredns. Mapping is configurable. To reduce load
// on the backend, a configurable cache is bundled.
package ldap
import (
"context"
"errors"
"strings"
"sync"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/etcd/msg"
"github.com/coredns/coredns/plugin/pkg/fall"
"github.com/coredns/coredns/plugin/pkg/upstream"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
"gopkg.in/ldap.v3"
)
// Ldap is an ldap plugin to serve zone entries from a ldap backend.
type Ldap struct {
Next plugin.Handler
Fall fall.F
Zones []string
Upstream *upstream.Upstream
Client ldap.Client
searchRequest *ldap.SearchRequest
ldapURL string
pagingLimit uint32
syncInterval time.Duration
username string
password string
sasl bool
zMu sync.RWMutex
}
// New returns an initialized Ldap with defaults.
func New(zones []string) *Ldap {
k := new(Ldap)
k.Zones = zones
k.pagingLimit = 0
// SearchRequest defaults
k.searchRequest = new(ldap.SearchRequest)
k.searchRequest.DerefAliases = ldap.NeverDerefAliases // TODO: Reason
k.searchRequest.Scope = ldap.ScopeWholeSubtree // search whole subtree
k.searchRequest.SizeLimit = 500 // TODO: Reason
k.searchRequest.TimeLimit = 500 // TODO: Reason
k.searchRequest.TypesOnly = false // TODO: Reason
return k
}
var (
errNoItems = errors.New("no items found")
errNsNotExposed = errors.New("namespace is not exposed")
errInvalidRequest = errors.New("invalid query name")
)
// InitClient initializes a Ldap client.
func (l *Ldap) InitClient() (err error) {
l.Client, err = ldap.DialURL(l.ldapURL)
if err != nil {
log.Fatal(err)
return err
}
defer l.Client.Close()
return nil
}
// Services implements the ServiceBackend interface.
func (l *Ldap) Services(ctx context.Context, state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error) {
services, err = l.Records(ctx, state, exact)
if err != nil {
return
}
services = msg.Group(services)
return
}
// Reverse implements the ServiceBackend interface.
func (l *Ldap) Reverse(ctx context.Context, state request.Request, exact bool, opt plugin.Options) (services []msg.Service, err error) {
return l.Services(ctx, state, exact, opt)
}
// Lookup implements the ServiceBackend interface.
func (l *Ldap) Lookup(ctx context.Context, state request.Request, name string, typ uint16) (*dns.Msg, error) {
return l.Upstream.Lookup(ctx, state, name, typ)
}
// IsNameError implements the ServiceBackend interface.
func (l *Ldap) IsNameError(err error) bool {
return err == errNoItems || err == errNsNotExposed || err == errInvalidRequest
}
// Records looks up records in ldap. If exact is true, it will lookup just this
// name. This is used when find matches when completing SRV lookups for instance.
func (l *Ldap) Records(ctx context.Context, state request.Request, exact bool) ([]msg.Service, error) {
name := state.Name()
path, star := msg.PathWithWildcard(name, l.PathPrefix)
r, err := l.get(ctx, path, !exact)
if err != nil {
return nil, err
}
segments := strings.Split(msg.Path(name, l.PathPrefix), "/")
return l.loopNodes(r.Kvs, segments, star, state.QType())
}