vendor-ed skydns

vendor/github.com/skynetservices/skydns/server/config.go

@@ -0,0 +1,157 @@
+// Copyright (c) 2014 The SkyDNS Authors. All rights reserved.
+// Use of this source code is governed by The MIT License (MIT) that can be
+// found in the LICENSE file.
+
+package server
+
+import (
+	"crypto"
+	"fmt"
+	"net"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+const (
+	SCacheCapacity = 10000
+	RCacheCapacity = 100000
+	RCacheTtl      = 60
+)
+
+// Config provides options to the SkyDNS resolver.
+type Config struct {
+	// The ip:port SkyDNS should be listening on for incoming DNS requests.
+	DnsAddr string `json:"dns_addr,omitempty"`
+	// bind to port(s) activated by systemd. If set to true, this overrides DnsAddr.
+	Systemd bool `json:"systemd,omitempty"`
+	// The domain SkyDNS is authoritative for, defaults to skydns.local.
+	Domain string `json:"domain,omitempty"`
+	// Domain pointing to a key where service info is stored when being queried
+	// for local.dns.skydns.local.
+	Local string `json:"local,omitempty"`
+	// The hostmaster responsible for this domain, defaults to hostmaster.<Domain>.
+	Hostmaster string `json:"hostmaster,omitempty"`
+	DNSSEC     string `json:"dnssec,omitempty"`
+	// Round robin A/AAAA replies. Default is true.
+	RoundRobin bool `json:"round_robin,omitempty"`
+	// Round robin selection of nameservers from among those listed, rather than have all forwarded requests try the first listed server first every time.
+	NSRotate bool `json:"ns_rotate,omitempty"`
+	// List of ip:port, seperated by commas of recursive nameservers to forward queries to.
+	Nameservers []string `json:"nameservers,omitempty"`
+	// Never provide a recursive service.
+	NoRec       bool          `json:"no_rec,omitempty"`
+	ReadTimeout time.Duration `json:"read_timeout,omitempty"`
+	// Default priority on SRV records when none is given. Defaults to 10.
+	Priority uint16 `json:"priority"`
+	// Default TTL, in seconds, when none is given in etcd. Defaults to 3600.
+	Ttl uint32 `json:"ttl,omitempty"`
+	// Minimum TTL, in seconds, for NXDOMAIN responses. Defaults to 300.
+	MinTtl uint32 `json:"min_ttl,omitempty"`
+	// SCache, capacity of the signature cache in signatures stored.
+	SCache int `json:"scache,omitempty"`
+	// RCache, capacity of response cache in resource records stored.
+	RCache int `json:"rcache,omitempty"`
+	// RCacheTtl, how long to cache in seconds.
+	RCacheTtl int `json:"rcache_ttl,omitempty"`
+	// How many labels a name should have before we allow forwarding. Default to 2.
+	Ndots int `json:"ndot,omitempty"`
+
+	// DNSSEC key material
+	PubKey  *dns.DNSKEY   `json:"-"`
+	KeyTag  uint16        `json:"-"`
+	PrivKey crypto.Signer `json:"-"`
+
+	Verbose bool `json:"-"`
+
+	Version bool
+
+	// some predefined string "constants"
+	localDomain string // "local.dns." + config.Domain
+	dnsDomain   string // "ns.dns". + config.Domain
+
+	// Stub zones support. Pointer to a map that we refresh when we see
+	// an update. Map contains domainname -> nameserver:port
+	stub *map[string][]string
+}
+
+func SetDefaults(config *Config) error {
+	if config.ReadTimeout == 0 {
+		config.ReadTimeout = 2 * time.Second
+	}
+	if config.DnsAddr == "" {
+		config.DnsAddr = "127.0.0.1:53"
+	}
+	if config.Domain == "" {
+		config.Domain = "skydns.local."
+	}
+	if config.Hostmaster == "" {
+		config.Hostmaster = appendDomain("hostmaster", config.Domain)
+	}
+	// People probably don't know that SOA's email addresses cannot
+	// contain @-signs, replace them with dots
+	config.Hostmaster = dns.Fqdn(strings.Replace(config.Hostmaster, "@", ".", -1))
+	if config.MinTtl == 0 {
+		config.MinTtl = 60
+	}
+	if config.Ttl == 0 {
+		config.Ttl = 3600
+	}
+	if config.Priority == 0 {
+		config.Priority = 10
+	}
+	if config.RCache < 0 {
+		config.RCache = 0
+	}
+	if config.SCache < 0 {
+		config.SCache = 0
+	}
+	if config.RCacheTtl == 0 {
+		config.RCacheTtl = RCacheTtl
+	}
+	if config.Ndots <= 0 {
+		config.Ndots = 2
+	}
+
+	if len(config.Nameservers) == 0 {
+		c, err := dns.ClientConfigFromFile("/etc/resolv.conf")
+		if !os.IsNotExist(err) {
+			if err != nil {
+				return err
+			}
+			for _, s := range c.Servers {
+				config.Nameservers = append(config.Nameservers, net.JoinHostPort(s, c.Port))
+			}
+		}
+	}
+	config.Domain = dns.Fqdn(strings.ToLower(config.Domain))
+	if config.DNSSEC != "" {
+		// For some reason the + are replaces by spaces in etcd. Re-replace them
+		keyfile := strings.Replace(config.DNSSEC, " ", "+", -1)
+		k, p, err := ParseKeyFile(keyfile)
+		if err != nil {
+			return err
+		}
+		if k.Header().Name != dns.Fqdn(config.Domain) {
+			return fmt.Errorf("ownername of DNSKEY must match SkyDNS domain")
+		}
+		k.Header().Ttl = config.Ttl
+		config.PubKey = k
+		config.KeyTag = k.KeyTag()
+		config.PrivKey = p
+	}
+	config.localDomain = appendDomain("local.dns", config.Domain)
+	config.dnsDomain = appendDomain("ns.dns", config.Domain)
+	stubmap := make(map[string][]string)
+	config.stub = &stubmap
+	return nil
+}
+
+func appendDomain(s1, s2 string) string {
+	if len(s2) > 0 && s2[0] == '.' {
+		return s1 + s2
+	}
+	return s1 + "." + s2
+}