From 9b8ca219a1f4a5863c35de766e2c367299bfd768 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Wed, 1 Jul 2020 10:17:08 -0700
Subject: [PATCH] wgengine/magicsock: remove allocs in UDP write, use new
 netaddr.PutUDPAddr

The allocs were only introduced yesterday with a TODO. Now they're gone again.
---
 go.mod                          | 2 +-
 go.sum                          | 2 ++
 wgengine/magicsock/magicsock.go | 5 +++--
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/go.mod b/go.mod
index 1f85c8ad8..2227aa42c 100644
--- a/go.mod
+++ b/go.mod
@@ -29,6 +29,6 @@ require (
 	golang.org/x/sys v0.0.0-20200501052902-10377860bb8e
 	golang.org/x/time v0.0.0-20191024005414-555d28b269f0
 	honnef.co/go/tools v0.0.1-2020.1.4 // indirect
-	inet.af/netaddr v0.0.0-20200629220211-f44a6d25c536
+	inet.af/netaddr v0.0.0-20200701171350-6509743f79d9
 	rsc.io/goversion v1.2.0
 )
diff --git a/go.sum b/go.sum
index 3b98b35f8..d01a0c902 100644
--- a/go.sum
+++ b/go.sum
@@ -162,5 +162,7 @@ inet.af/netaddr v0.0.0-20200513162223-787f13e36cbe h1:WjJ6wZhXEWQA3FFSwOjG8tO2q1
 inet.af/netaddr v0.0.0-20200513162223-787f13e36cbe/go.mod h1:qqYzz/2whtrbWJvt+DNWQyvekNN4ePQZcg2xc2/Yjww=
 inet.af/netaddr v0.0.0-20200629220211-f44a6d25c536 h1:XFVw2MVOtmHBidx70M+I6vIw2F6f55UyXvkiKfIrE38=
 inet.af/netaddr v0.0.0-20200629220211-f44a6d25c536/go.mod h1:qqYzz/2whtrbWJvt+DNWQyvekNN4ePQZcg2xc2/Yjww=
+inet.af/netaddr v0.0.0-20200701171350-6509743f79d9 h1:F41nQsn8UGDPDXsOPwZQiaK8BmItPzyb0PYgjJSYIzw=
+inet.af/netaddr v0.0.0-20200701171350-6509743f79d9/go.mod h1:qqYzz/2whtrbWJvt+DNWQyvekNN4ePQZcg2xc2/Yjww=
 rsc.io/goversion v1.2.0 h1:SPn+NLTiAG7w30IRK/DKp1BjvpWabYgxlLp/+kx5J8w=
 rsc.io/goversion v1.2.0/go.mod h1:Eih9y/uIBS3ulggl7KNJ09xGSLcuNaLgmvvqa07sgfo=
diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index 68a5612e8..c24610076 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -805,8 +805,9 @@ func (c *Conn) Send(b []byte, ep conn.Endpoint) error {
 
 // sendUDP sends UDP packet b to ipp.
 func (c *Conn) sendUDP(ipp netaddr.IPPort, b []byte) error {
-	addr := ipp.UDPAddr() // TOOD(bradfitz): add alloc-free netaddr.WriteTo helper
-	return c.sendUDPStd(addr, b)
+	ua := ipp.UDPAddr()
+	defer netaddr.PutUDPAddr(ua)
+	return c.sendUDPStd(ua, b)
 }
 
 func (c *Conn) sendUDPStd(addr *net.UDPAddr, b []byte) (err error) {