From adb577d4a45e341da53c4d9196ad4222c9a23e69 Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@google.com>
Date: Tue, 12 Mar 2019 12:34:31 -0700
Subject: [PATCH] Add support for IFLA_GSO_*

IFLA_GSO_MAX_SIZE - maximum GSO segment size
IFLA_GSO_MAX_SEGS - maximum number of GSO segments

Signed-off-by: Andrei Vagin <avagin@google.com>
---
 link.go       |  2 ++
 link_linux.go | 14 ++++++++++++++
 link_test.go  | 30 ++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/link.go b/link.go
index bbf117e..c142b22 100644
--- a/link.go
+++ b/link.go
@@ -41,6 +41,8 @@ type LinkAttrs struct {
 	NetNsID      int
 	NumTxQueues  int
 	NumRxQueues  int
+	GSOMaxSize   uint32
+	GSOMaxSegs   uint32
 	Vfs          []VfInfo // virtual functions available on link
 }
 
diff --git a/link_linux.go b/link_linux.go
index 855fabb..f7e4863 100644
--- a/link_linux.go
+++ b/link_linux.go
@@ -1118,6 +1118,16 @@ func (h *Handle) linkModify(link Link, flags int) error {
 		req.AddData(rxqueues)
 	}
 
+	if base.GSOMaxSegs > 0 {
+		gsoAttr := nl.NewRtAttr(unix.IFLA_GSO_MAX_SEGS, nl.Uint32Attr(base.GSOMaxSegs))
+		req.AddData(gsoAttr)
+	}
+
+	if base.GSOMaxSize > 0 {
+		gsoAttr := nl.NewRtAttr(unix.IFLA_GSO_MAX_SIZE, nl.Uint32Attr(base.GSOMaxSize))
+		req.AddData(gsoAttr)
+	}
+
 	if base.Namespace != nil {
 		var attr *nl.RtAttr
 		switch ns := base.Namespace.(type) {
@@ -1537,6 +1547,10 @@ func LinkDeserialize(hdr *unix.NlMsghdr, m []byte) (Link, error) {
 			base.OperState = LinkOperState(uint8(attr.Value[0]))
 		case unix.IFLA_LINK_NETNSID:
 			base.NetNsID = int(native.Uint32(attr.Value[0:4]))
+		case unix.IFLA_GSO_MAX_SIZE:
+			base.GSOMaxSize = native.Uint32(attr.Value[0:4])
+		case unix.IFLA_GSO_MAX_SEGS:
+			base.GSOMaxSegs = native.Uint32(attr.Value[0:4])
 		case unix.IFLA_VFINFO_LIST:
 			data, err := nl.ParseRouteAttr(attr.Value)
 			if err != nil {
diff --git a/link_test.go b/link_test.go
index e154204..98597fb 100644
--- a/link_test.go
+++ b/link_test.go
@@ -694,6 +694,36 @@ func TestLinkAddVethWithZeroTxQLen(t *testing.T) {
 	}
 }
 
+func TestLinkAddDelDummyWithGSO(t *testing.T) {
+	const (
+		gsoMaxSegs = 16
+		gsoMaxSize = 1 << 14
+	)
+	minKernelRequired(t, 4, 16)
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	dummy := &Dummy{LinkAttrs: LinkAttrs{Name: "foo", GSOMaxSize: gsoMaxSize, GSOMaxSegs: gsoMaxSegs}}
+	if err := LinkAdd(dummy); err != nil {
+		t.Fatal(err)
+	}
+	link, err := LinkByName("foo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	dummy, ok := link.(*Dummy)
+	if !ok {
+		t.Fatalf("unexpected link type: %T", link)
+	}
+
+	if dummy.GSOMaxSize != gsoMaxSize {
+		t.Fatalf("GSOMaxSize is %d, should be %d", dummy.GSOMaxSize, gsoMaxSize)
+	}
+	if dummy.GSOMaxSegs != gsoMaxSegs {
+		t.Fatalf("GSOMaxSeg is %d, should be %d", dummy.GSOMaxSegs, gsoMaxSegs)
+	}
+}
+
 func TestLinkAddDummyWithTxQLen(t *testing.T) {
 	tearDown := setUpNetlinkTest(t)
 	defer tearDown()