From fa626839b1a55dc7ea235cde0fcfe928f7197c2a Mon Sep 17 00:00:00 2001
From: Michael Stapelberg <stapelberg@google.com>
Date: Mon, 28 May 2018 09:53:54 +0200
Subject: [PATCH] Working radvd

---
 cmd/dhcp4/dhcp4.go              |  2 +-
 cmd/dhcp6/dhcp6.go              |  2 +-
 cmd/netconfigd/netconfigd.go    | 15 ++++++++++++---
 integrationnetconfig_test.go    |  2 +-
 internal/netconfig/netconfig.go | 25 ++++++++++++++++---------
 5 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/cmd/dhcp4/dhcp4.go b/cmd/dhcp4/dhcp4.go
index 5158807..b4ddee0 100644
--- a/cmd/dhcp4/dhcp4.go
+++ b/cmd/dhcp4/dhcp4.go
@@ -1,4 +1,4 @@
-// Binary dhcp4 obtains a DHCPv4 lease, persists its contents to
+// Binary dhcp4 obtains a DHCPv4 lease, persists it to
 // /perm/dhcp4/wire/lease.json and notifies netconfigd.
 package main
 
diff --git a/cmd/dhcp6/dhcp6.go b/cmd/dhcp6/dhcp6.go
index 5e16cbd..c887516 100644
--- a/cmd/dhcp6/dhcp6.go
+++ b/cmd/dhcp6/dhcp6.go
@@ -1,4 +1,4 @@
-// Binary dhcp6 obtains a DHCPv6 lease, persists its contents to
+// Binary dhcp6 obtains a DHCPv6 lease, persists it to
 // /perm/dhcp6/wire/lease.json and notifies netconfigd.
 package main
 
diff --git a/cmd/netconfigd/netconfigd.go b/cmd/netconfigd/netconfigd.go
index 8fa09ad..1edc91c 100644
--- a/cmd/netconfigd/netconfigd.go
+++ b/cmd/netconfigd/netconfigd.go
@@ -21,12 +21,21 @@ func logic() error {
 	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGUSR1)
 	for {
-		if err := netconfig.Apply("uplink0", "/perm/"); err != nil {
+		err := netconfig.Apply("uplink0", "/perm/")
+		// Notify gokrazy about new addresses (netconfig.Apply might have
+		// modified state before returning an error) so that listeners can be
+		// updated.
+		p, _ := os.FindProcess(1)
+		if err := p.Signal(syscall.SIGHUP); err != nil {
+			log.Printf("kill -HUP 1: %v", err)
+		}
+		if err != nil {
 			return err
 		}
-		if *linger {
-			<-ch
+		if !*linger {
+			break
 		}
+		<-ch
 	}
 	return nil
 }
diff --git a/integrationnetconfig_test.go b/integrationnetconfig_test.go
index b448570..9f69b13 100644
--- a/integrationnetconfig_test.go
+++ b/integrationnetconfig_test.go
@@ -114,7 +114,7 @@ func TestNetconfig(t *testing.T) {
 	if !addrRe.MatchString(string(addrs)) {
 		t.Fatalf("regexp %s does not match %s", addrRe, string(addrs))
 	}
-	addr6Re := regexp.MustCompile(`(?m)^\s*inet6 2a02:168:4a00::1/48 scope global\s*$`)
+	addr6Re := regexp.MustCompile(`(?m)^\s*inet6 2a02:168:4a00::1/64 scope global\s*$`)
 	if !addr6Re.MatchString(string(addrs)) {
 		t.Fatalf("regexp %s does not match %s", addr6Re, string(addrs))
 	}
diff --git a/internal/netconfig/netconfig.go b/internal/netconfig/netconfig.go
index 7e93b98..b85bf99 100644
--- a/internal/netconfig/netconfig.go
+++ b/internal/netconfig/netconfig.go
@@ -6,11 +6,9 @@ import (
 	"io/ioutil"
 	"log"
 	"net"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
-	"syscall"
 
 	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
@@ -123,6 +121,10 @@ func applyDhcp6(iface, dir string) error {
 		// pick the first address of the prefix, e.g. address 2a02:168:4a00::1
 		// for prefix 2a02:168:4a00::/48
 		prefix.IP[len(prefix.IP)-1] = 1
+		// Use the first /64 subnet within larger prefixes
+		if ones, bits := prefix.Mask.Size(); ones < 64 {
+			prefix.Mask = net.CIDRMask(64, bits)
+		}
 		addr, err := netlink.ParseAddr(prefix.String())
 		if err != nil {
 			return err
@@ -220,12 +222,23 @@ func applyFirewall() error {
 
 func applySysctl() error {
 	if err := ioutil.WriteFile("/proc/sys/net/ipv4/ip_forward", []byte("1"), 0644); err != nil {
-		return err
+		return fmt.Errorf("sysctl(net.ipv4.ip_forward=1): %v", err)
 	}
+
+	if err := ioutil.WriteFile("/proc/sys/net/ipv6/conf/all/forwarding", []byte("1"), 0644); err != nil {
+		return fmt.Errorf("sysctl(net.ipv6.conf.all.forwarding=1): %v", err)
+	}
+
+	if err := ioutil.WriteFile("/proc/sys/net/ipv6/conf/uplink0/accept_ra", []byte("2"), 0644); err != nil {
+		return fmt.Errorf("sysctl(net.ipv6.conf.uplink0.accept_ra=2): %v", err)
+	}
+
 	return nil
 }
 
 func Apply(iface, dir string) error {
+
+	// TODO: split into two parts: delay the up until later
 	if err := applyInterfaces(dir); err != nil {
 		return err
 	}
@@ -246,11 +259,5 @@ func Apply(iface, dir string) error {
 		return err
 	}
 
-	// Notify gokrazy init of new addresses
-	p, _ := os.FindProcess(1)
-	if err := p.Signal(syscall.SIGHUP); err != nil {
-		log.Printf("send SIGHUP to init: %v", err)
-	}
-
 	return nil
 }