Use Go Control API

.gx/lastpubver

@@ -1 +1 @@
-0.1.19: QmXD921xzL9EDRpD6gRm1cb7Khm8VEpZ3NT3nPK7uTX6Fq
+0.1.19: QmXpK6aZZpAG38T6aSDBiYPU8wvDoHSczWmXurJzr82j4j

README.md

@@ -3,7 +3,7 @@
 [![travisbadge](https://travis-ci.org/libp2p/go-reuseport.svg)](https://travis-ci.org/libp2p/go-reuseport)
 
 This package enables listening and dialing from _the same_ TCP or UDP port.
-This means that the following sockopts are set:
+This means that the following sockopts may be set:
 
 ```
 SO_REUSEADDR
@@ -12,12 +12,10 @@ SO_REUSEPORT
 
 - godoc: https://godoc.org/github.com/libp2p/go-reuseport
 
-This is a simple package to get around the problem of reusing addresses.
-The go `net` package (to my knowledge) does not allow setting socket options.
-This is particularly problematic when attempting to do TCP NAT holepunching,
-which requires a process to both Listen and Dial on the same TCP port.
-This package makes this possible for me. It is a pretty narrow use case, but
-perhaps this package can grow to be more general over time.
+This is a simple package to help with address reuse. This is particularly
+important when attempting to do TCP NAT holepunching, which requires a process
+to both Listen and Dial on the same TCP port. This package provides some
+utilities around enabling this behaviour on various OS.
 
 ## Examples
 
@@ -39,4 +37,4 @@ c, _ := reuse.Dial("tcp", "127.0.0.1:1234", "127.0.0.1:1235")
 
 ## Tested
 
-Tested on `darwin` and `linux`.
+Tested on `darwin`, `linux`, and `windows`.

control_unix.go

@@ -0,0 +1,25 @@
+// +build !windows
+
+package reuseport
+
+import (
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func Control(network, address string, c syscall.RawConn) error {
+	var err error
+	c.Control(func(fd uintptr) {
+		err = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEADDR, 1)
+		if err != nil {
+			return
+		}
+
+		err = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1)
+		if err != nil {
+			return
+		}
+	})
+	return err
+}

control_windows.go

@@ -0,0 +1,13 @@
+package reuseport
+
+import (
+	"syscall"
+
+	"golang.org/x/sys/windows"
+)
+
+func Control(network, address string, c syscall.RawConn) (err error) {
+	return c.Control(func(fd uintptr) {
+		err = windows.SetsockoptInt(windows.Handle(fd), windows.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+	})
+}

go.mod

@@ -0,0 +1,9 @@
+module github.com/libp2p/go-reuseport
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pkg/errors v0.8.0
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.2.2
+	golang.org/x/sys v0.0.0-20190102155601-82a175fd1598
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
+github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/sys v0.0.0-20190102155601-82a175fd1598 h1:S8GOgffXV1X3fpVG442QRfWOt0iFl79eHJ7OPt725bo=
+golang.org/x/sys v0.0.0-20190102155601-82a175fd1598/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=