conn: separate gso and sticky control

Android wants GSO but not sticky.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 266 insertions, 0 deletions

diff --git a/conn/sticky_linux_test.go b/conn/sticky_linux_test.go
new file mode 100644
index 0000000..d2bd584
--- /dev/null
+++ b/conn/sticky_linux_test.go
@@ -0,0 +1,266 @@
+//go:build linux && !android
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+import (
+	"context"
+	"net"
+	"net/netip"
+	"runtime"
+	"testing"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+func setSrc(ep *StdNetEndpoint, addr netip.Addr, ifidx int32) {
+	var buf []byte
+	if addr.Is4() {
+		buf = make([]byte, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
+		hdr := unix.Cmsghdr{
+			Level: unix.IPPROTO_IP,
+			Type:  unix.IP_PKTINFO,
+		}
+		hdr.SetLen(unix.CmsgLen(unix.SizeofInet4Pktinfo))
+		copy(buf, unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), int(unsafe.Sizeof(hdr))))
+
+		info := unix.Inet4Pktinfo{
+			Ifindex:  ifidx,
+			Spec_dst: addr.As4(),
+		}
+		copy(buf[unix.CmsgLen(0):], unsafe.Slice((*byte)(unsafe.Pointer(&info)), unix.SizeofInet4Pktinfo))
+	} else {
+		buf = make([]byte, unix.CmsgSpace(unix.SizeofInet6Pktinfo))
+		hdr := unix.Cmsghdr{
+			Level: unix.IPPROTO_IPV6,
+			Type:  unix.IPV6_PKTINFO,
+		}
+		hdr.SetLen(unix.CmsgLen(unix.SizeofInet6Pktinfo))
+		copy(buf, unsafe.Slice((*byte)(unsafe.Pointer(&hdr)), int(unsafe.Sizeof(hdr))))
+
+		info := unix.Inet6Pktinfo{
+			Ifindex: uint32(ifidx),
+			Addr:    addr.As16(),
+		}
+		copy(buf[unix.CmsgLen(0):], unsafe.Slice((*byte)(unsafe.Pointer(&info)), unix.SizeofInet6Pktinfo))
+	}
+
+	ep.src = buf
+}
+
+func Test_setSrcControl(t *testing.T) {
+	t.Run("IPv4", func(t *testing.T) {
+		ep := &StdNetEndpoint{
+			AddrPort: netip.MustParseAddrPort("127.0.0.1:1234"),
+		}
+		setSrc(ep, netip.MustParseAddr("127.0.0.1"), 5)
+
+		control := make([]byte, stickyControlSize)
+
+		setSrcControl(&control, ep)
+
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		if hdr.Level != unix.IPPROTO_IP {
+			t.Errorf("unexpected level: %d", hdr.Level)
+		}
+		if hdr.Type != unix.IP_PKTINFO {
+			t.Errorf("unexpected type: %d", hdr.Type)
+		}
+		if uint(hdr.Len) != uint(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet4Pktinfo{})))) {
+			t.Errorf("unexpected length: %d", hdr.Len)
+		}
+		info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+		if info.Spec_dst[0] != 127 || info.Spec_dst[1] != 0 || info.Spec_dst[2] != 0 || info.Spec_dst[3] != 1 {
+			t.Errorf("unexpected address: %v", info.Spec_dst)
+		}
+		if info.Ifindex != 5 {
+			t.Errorf("unexpected ifindex: %d", info.Ifindex)
+		}
+	})
+
+	t.Run("IPv6", func(t *testing.T) {
+		ep := &StdNetEndpoint{
+			AddrPort: netip.MustParseAddrPort("[::1]:1234"),
+		}
+		setSrc(ep, netip.MustParseAddr("::1"), 5)
+
+		control := make([]byte, stickyControlSize)
+
+		setSrcControl(&control, ep)
+
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		if hdr.Level != unix.IPPROTO_IPV6 {
+			t.Errorf("unexpected level: %d", hdr.Level)
+		}
+		if hdr.Type != unix.IPV6_PKTINFO {
+			t.Errorf("unexpected type: %d", hdr.Type)
+		}
+		if uint(hdr.Len) != uint(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet6Pktinfo{})))) {
+			t.Errorf("unexpected length: %d", hdr.Len)
+		}
+		info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+		if info.Addr != ep.SrcIP().As16() {
+			t.Errorf("unexpected address: %v", info.Addr)
+		}
+		if info.Ifindex != 5 {
+			t.Errorf("unexpected ifindex: %d", info.Ifindex)
+		}
+	})
+
+	t.Run("ClearOnNoSrc", func(t *testing.T) {
+		control := make([]byte, stickyControlSize)
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		hdr.Level = 1
+		hdr.Type = 2
+		hdr.Len = 3
+
+		setSrcControl(&control, &StdNetEndpoint{})
+
+		if len(control) != 0 {
+			t.Errorf("unexpected control: %v", control)
+		}
+	})
+}
+
+func Test_getSrcFromControl(t *testing.T) {
+	t.Run("IPv4", func(t *testing.T) {
+		control := make([]byte, stickyControlSize)
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		hdr.Level = unix.IPPROTO_IP
+		hdr.Type = unix.IP_PKTINFO
+		hdr.SetLen(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet4Pktinfo{}))))
+		info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+		info.Spec_dst = [4]byte{127, 0, 0, 1}
+		info.Ifindex = 5
+
+		ep := &StdNetEndpoint{}
+		getSrcFromControl(control, ep)
+
+		if ep.SrcIP() != netip.MustParseAddr("127.0.0.1") {
+			t.Errorf("unexpected address: %v", ep.SrcIP())
+		}
+		if ep.SrcIfidx() != 5 {
+			t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
+		}
+	})
+	t.Run("IPv6", func(t *testing.T) {
+		control := make([]byte, stickyControlSize)
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		hdr.Level = unix.IPPROTO_IPV6
+		hdr.Type = unix.IPV6_PKTINFO
+		hdr.SetLen(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet6Pktinfo{}))))
+		info := (*unix.Inet6Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+		info.Addr = [16]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+		info.Ifindex = 5
+
+		ep := &StdNetEndpoint{}
+		getSrcFromControl(control, ep)
+
+		if ep.SrcIP() != netip.MustParseAddr("::1") {
+			t.Errorf("unexpected address: %v", ep.SrcIP())
+		}
+		if ep.SrcIfidx() != 5 {
+			t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
+		}
+	})
+	t.Run("ClearOnEmpty", func(t *testing.T) {
+		var control []byte
+		ep := &StdNetEndpoint{}
+		setSrc(ep, netip.MustParseAddr("::1"), 5)
+
+		getSrcFromControl(control, ep)
+		if ep.SrcIP().IsValid() {
+			t.Errorf("unexpected address: %v", ep.SrcIP())
+		}
+		if ep.SrcIfidx() != 0 {
+			t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
+		}
+	})
+	t.Run("Multiple", func(t *testing.T) {
+		zeroControl := make([]byte, unix.CmsgSpace(0))
+		zeroHdr := (*unix.Cmsghdr)(unsafe.Pointer(&zeroControl[0]))
+		zeroHdr.SetLen(unix.CmsgLen(0))
+
+		control := make([]byte, unix.CmsgSpace(unix.SizeofInet4Pktinfo))
+		hdr := (*unix.Cmsghdr)(unsafe.Pointer(&control[0]))
+		hdr.Level = unix.IPPROTO_IP
+		hdr.Type = unix.IP_PKTINFO
+		hdr.SetLen(unix.CmsgLen(int(unsafe.Sizeof(unix.Inet4Pktinfo{}))))
+		info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&control[unix.CmsgLen(0)]))
+		info.Spec_dst = [4]byte{127, 0, 0, 1}
+		info.Ifindex = 5
+
+		combined := make([]byte, 0)
+		combined = append(combined, zeroControl...)
+		combined = append(combined, control...)
+
+		ep := &StdNetEndpoint{}
+		getSrcFromControl(combined, ep)
+
+		if ep.SrcIP() != netip.MustParseAddr("127.0.0.1") {
+			t.Errorf("unexpected address: %v", ep.SrcIP())
+		}
+		if ep.SrcIfidx() != 5 {
+			t.Errorf("unexpected ifindex: %d", ep.SrcIfidx())
+		}
+	})
+}
+
+func Test_listenConfig(t *testing.T) {
+	t.Run("IPv4", func(t *testing.T) {
+		conn, err := listenConfig().ListenPacket(context.Background(), "udp4", ":0")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer conn.Close()
+		sc, err := conn.(*net.UDPConn).SyscallConn()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if runtime.GOOS == "linux" {
+			var i int
+			sc.Control(func(fd uintptr) {
+				i, err = unix.GetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_PKTINFO)
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if i != 1 {
+				t.Error("IP_PKTINFO not set!")
+			}
+		} else {
+			t.Logf("listenConfig() does not set IPV6_RECVPKTINFO on %s", runtime.GOOS)
+		}
+	})
+	t.Run("IPv6", func(t *testing.T) {
+		conn, err := listenConfig().ListenPacket(context.Background(), "udp6", ":0")
+		if err != nil {
+			t.Fatal(err)
+		}
+		sc, err := conn.(*net.UDPConn).SyscallConn()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if runtime.GOOS == "linux" {
+			var i int
+			sc.Control(func(fd uintptr) {
+				i, err = unix.GetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_RECVPKTINFO)
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if i != 1 {
+				t.Error("IPV6_PKTINFO not set!")
+			}
+		} else {
+			t.Logf("listenConfig() does not set IPV6_RECVPKTINFO on %s", runtime.GOOS)
+		}
+	})
+}