From 6ecbdef112b3bf0759a60914d0eb08540c5274ed Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Sun, 3 Apr 2016 07:37:41 +0100
Subject: [PATCH] Add notifies to master servers

This adds a bunch of supporting code to send notifies to a primary

name server.
---
 core/setup/file.go        |  4 +++-
 middleware/file/README.md |  4 +++-
 middleware/file/notify.go | 39 +++++++++++++++++++++++++++++++++++----
 middleware/file/zone.go   |  3 +--
 middleware/host.go        | 22 ++++++++++++++++++----
 5 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/core/setup/file.go b/core/setup/file.go
index 7128b77aa..aca9f8f9f 100644
--- a/core/setup/file.go
+++ b/core/setup/file.go
@@ -13,6 +13,8 @@ func File(c *Controller) (middleware.Middleware, error) {
 	if err != nil {
 		return nil, err
 	}
+	// Set start function is transfer is specified
+
 	return func(next middleware.Handler) middleware.Handler {
 		return file.File{Next: next, Zones: zones}
 	}, nil
@@ -35,7 +37,7 @@ func fileParse(c *Controller) (file.Zones, error) {
 				origin = c.Val()
 			}
 			// normalize this origin
-			origin = middleware.Host(origin).StandardHost()
+			origin = middleware.Host(origin).Standard()
 
 			reader, err := os.Open(fileName)
 			if err != nil {
diff --git a/middleware/file/README.md b/middleware/file/README.md
index bd9a24d1e..407c1119c 100644
--- a/middleware/file/README.md
+++ b/middleware/file/README.md
@@ -17,9 +17,11 @@ file dbfile [zones...]
 
 If you want to round robin A and AAAA responses look at the `loadbalance` middleware.
 
+TSIG key configuration is TODO; directive format will change.
+
 ~~~
 file dbfile [zones... ] {
-    transfer in|out
+    transfer out [address...]
 }
 ~~~
 
diff --git a/middleware/file/notify.go b/middleware/file/notify.go
index cb61cc050..58cc66e79 100644
--- a/middleware/file/notify.go
+++ b/middleware/file/notify.go
@@ -1,8 +1,39 @@
 package file
 
-// Notify sends notifies to the configured remotes. It will try up to three times
-// before giving up on a specific remote.
-func Notify(remotes []string) error {
-	return nil
+import (
+	"fmt"
 
+	"github.com/miekg/coredns/middleware"
+	"github.com/miekg/dns"
+)
+
+// Notify will send notifies to all configured IP addresses.
+func (z *Zone) Notify() {
+	go notify(z.name, z.Peers)
+}
+
+// notify sends notifies to the configured remotes. It will try up to three times
+// before giving up on a specific remote. We will sequentially loop through the remotes
+// until they all have replied (or have 3 failed attempts).
+func notify(zone string, remotes []string) error {
+	m := new(dns.Msg)
+	m.SetNotify(zone)
+	c := new(dns.Client)
+
+	// TODO(miek): error handling? Run this in a goroutine?
+	for _, remote := range remotes {
+		notifyRemote(c, m, middleware.Addr(remote).Standard())
+	}
+	return nil
+}
+
+func notifyRemote(c *dns.Client, m *dns.Msg, s string) error {
+	for i := 0; i < 3; i++ {
+		ret, err := middleware.Exchange(c, m, s)
+		if err == nil && ret.Rcode == dns.RcodeSuccess || ret.Rcode == dns.RcodeNotImplemented {
+			return nil
+		}
+		// timeout? mean don't want it. should stop sending as well
+	}
+	return fmt.Errorf("failed to send notify for zone '%s' to '%s'", m.Question[0].Name, s)
 }
diff --git a/middleware/file/zone.go b/middleware/file/zone.go
index 1547a23b4..8c56b6bf9 100644
--- a/middleware/file/zone.go
+++ b/middleware/file/zone.go
@@ -10,7 +10,6 @@ import (
 type Transfer struct {
 	Out bool
 	In  bool
-	// more later?
 }
 
 type Zone struct {
@@ -18,7 +17,7 @@ type Zone struct {
 	SIG  []dns.RR
 	name string
 	*tree.Tree
-	Masters  []string
+	Peers    []string
 	Transfer *Transfer
 }
 
diff --git a/middleware/host.go b/middleware/host.go
index 17ecedb5f..7b9b9a42a 100644
--- a/middleware/host.go
+++ b/middleware/host.go
@@ -7,12 +7,15 @@ import (
 	"github.com/miekg/dns"
 )
 
-// Host represents a host from the Caddyfile, may contain port.
-type Host string
+// Host represents a host from the Corefile, may contain port.
+type (
+	Host string
+	Addr string
+)
 
-// Standard host will return the host portion of host, stripping
+// Standard will return the host portion of host, stripping
 // of any port. The host will also be fully qualified and lowercased.
-func (h Host) StandardHost() string {
+func (h Host) Standard() string {
 	// separate host and port
 	host, _, err := net.SplitHostPort(string(h))
 	if err != nil {
@@ -20,3 +23,14 @@ func (h Host) StandardHost() string {
 	}
 	return strings.ToLower(dns.Fqdn(host))
 }
+
+// Standard will return a normalized address, if not port is specified
+// port 53 is added, otherwise the port will be left as is.
+func (a Addr) Standard() string {
+	// separate host and port
+	addr, port, err := net.SplitHostPort(string(a))
+	if err != nil {
+		addr, port, _ = net.SplitHostPort(string(a) + ":53")
+	}
+	return net.JoinHostPort(addr, port)
+}