From f791660608619b14455325beb19396803804d893 Mon Sep 17 00:00:00 2001
From: Nikita Kryuchkov <nkryuchkov10@gmail.com>
Date: Wed, 4 Mar 2020 19:31:04 +0100
Subject: [PATCH] Fix bug with atomic for 32 bit architectures

---
 pkg/router/route_group.go       |  6 +++---
 pkg/router/route_group_test.go  |  7 +++++++
 pkg/util/alignment/alignment.go | 20 ++++++++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 pkg/util/alignment/alignment.go

diff --git a/pkg/router/route_group.go b/pkg/router/route_group.go
index 3a3cd96ea..121212537 100644
--- a/pkg/router/route_group.go
+++ b/pkg/router/route_group.go
@@ -67,6 +67,8 @@ type RouteGroup struct {
 	desc   routing.RouteDescriptor // describes the route group
 	rt     routing.Table
 
+	lastSent int64
+
 	// 'tps' is transports used for writing/forward rules.
 	// It should have the same number of elements as 'fwd'
 	// where each element corresponds with the adjacent element in 'fwd'.
@@ -79,15 +81,12 @@ type RouteGroup struct {
 	fwd []routing.Rule // forward rules (for writing)
 	rvs []routing.Rule // reverse rules (for reading)
 
-	lastSent int64
-
 	// 'readCh' reads in incoming packets of this route group.
 	// - Router should serve call '(*transport.Manager).ReadPacket' in a loop,
 	//      and push to the appropriate '(RouteGroup).readCh'.
 	readCh   chan []byte // push reads from Router
 	readChMu sync.Mutex
 	readBuf  bytes.Buffer // for read overflow
-	once     sync.Once
 
 	readDeadline  deadline.PipeDeadline
 	writeDeadline deadline.PipeDeadline
@@ -99,6 +98,7 @@ type RouteGroup struct {
 	closed           chan struct{}
 	// used to wait for all the `Close` packets to run through the loop and come back
 	closeDone sync.WaitGroup
+	once      sync.Once
 }
 
 // NewRouteGroup creates a new RouteGroup.
diff --git a/pkg/router/route_group_test.go b/pkg/router/route_group_test.go
index bb5d07620..e61f747d5 100644
--- a/pkg/router/route_group_test.go
+++ b/pkg/router/route_group_test.go
@@ -28,6 +28,13 @@ func TestNewRouteGroup(t *testing.T) {
 	require.Equal(t, DefaultRouteGroupConfig(), rg.cfg)
 }
 
+// Uncomment for debugging
+/*
+func TestRouteGroupAlignment(t *testing.T) {
+	alignment.PrintStruct(RouteGroup{})
+}
+*/
+
 func TestRouteGroup_Close(t *testing.T) {
 	rg1, rg2, m1, m2, teardown := setupEnv(t)
 
diff --git a/pkg/util/alignment/alignment.go b/pkg/util/alignment/alignment.go
new file mode 100644
index 000000000..aad1a3b8d
--- /dev/null
+++ b/pkg/util/alignment/alignment.go
@@ -0,0 +1,20 @@
+package alignment
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// PrintStruct prints detailed information of struct fields alignment.
+func PrintStruct(v interface{}) {
+	typ := reflect.TypeOf(v)
+	fmt.Printf("Struct is %d bytes long\n", typ.Size())
+	// We can run through the fields in the structure in order
+	n := typ.NumField()
+	for i := 0; i < n; i++ {
+		field := typ.Field(i)
+		fmt.Printf("%s at offset %v, size=%d, align=%d\n",
+			field.Name, field.Offset, field.Type.Size(),
+			field.Type.Align())
+	}
+}