From af3e1b2ea9b0dd6b873f2d32f91b07eeab3b4610 Mon Sep 17 00:00:00 2001
From: Callan Bryant <callan.bryant@gmail.com>
Date: Sun, 25 Oct 2020 08:23:43 +0000
Subject: [PATCH] make allocation universal, given a network

---
 add.go         |  4 +++-
 configtypes.go | 11 +++++++----
 init.go        |  5 +++--
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/add.go b/add.go
index af5c75b..d1ed195 100644
--- a/add.go
+++ b/add.go
@@ -62,7 +62,8 @@ func Add() {
 	privateKey := GenerateJSONPrivateKey()
 	publicKey := privateKey.PublicKey()
 
-	IP := conf.MustAllocateIP()
+	IP := conf.MustAllocateIP(conf.Network.IPNet)
+	//IP6 := conf.MustAllocateIP(conf.Network6.IPNet)
 
 	peer := PeerConfig{
 		Owner:        owner,
@@ -73,6 +74,7 @@ func Add() {
 		PrivateKey:   privateKey, // omitted from server config JSON!
 		PresharedKey: GenerateJSONKey(),
 		IP:           IP,
+		//IP6:          IP6,
 		Networks:     []JSONIPNet{},
 	}
 
diff --git a/configtypes.go b/configtypes.go
index 449c264..5f5ed3f 100644
--- a/configtypes.go
+++ b/configtypes.go
@@ -154,12 +154,15 @@ func (conf DsnetConfig) IPAllocated(IP net.IP) bool {
 }
 
 // choose a free IP for a new Peer
-func (conf DsnetConfig) MustAllocateIP() net.IP {
-	network := conf.Network.IPNet
+func (conf DsnetConfig) MustAllocateIP(network net.IPNet) net.IP {
 	ones, bits := network.Mask.Size()
 	zeros := bits - ones
-	min := 1                // avoids network addr
-	max := (1 << zeros) - 2 // avoids broadcast addr + overflow
+
+	// avoids network addr
+	min := 1
+	// avoids broadcast addr + overflow. Note there is no broadcast addr with
+	// IPv6, but I don't care about losing one when there are so many!
+	max := (1 << zeros) - 2
 
 	for i := min; i <= max; i++ {
 		IP := make(net.IP, len(network.IP))
diff --git a/init.go b/init.go
index 27bc830..5321b4f 100644
--- a/init.go
+++ b/init.go
@@ -31,8 +31,9 @@ func Init() {
 		Networks:      []JSONIPNet{},
 	}
 
-	IP := conf.MustAllocateIP()
-	conf.IP = IP
+	conf.IP = conf.MustAllocateIP(conf.Network.IPNet)
+	//conf.IP6 = conf.MustAllocateIP(conf.Network6.IPNet)
+
 	// DNS not set by default
 	//conf.DNS = IP