gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/tcpip/transport/tcp/segment_test.go (about)

     1  // Copyright 2021 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tcp
    16  
    17  import (
    18  	"testing"
    19  
    20  	"github.com/google/go-cmp/cmp"
    21  	"gvisor.dev/gvisor/pkg/buffer"
    22  	"gvisor.dev/gvisor/pkg/tcpip/faketime"
    23  	"gvisor.dev/gvisor/pkg/tcpip/stack"
    24  )
    25  
    26  const trueSegSize = stack.PacketBufferStructSize + segSize
    27  
    28  type segmentSizeWants struct {
    29  	DataSize   int
    30  	SegMemSize int
    31  }
    32  
    33  func checkSegmentSize(t *testing.T, name string, seg *segment, want segmentSizeWants) {
    34  	t.Helper()
    35  	got := segmentSizeWants{
    36  		DataSize:   seg.payloadSize(),
    37  		SegMemSize: seg.segMemSize(),
    38  	}
    39  	if diff := cmp.Diff(want, got); diff != "" {
    40  		t.Errorf("%s differs (-want +got):\n%s", name, diff)
    41  	}
    42  }
    43  
    44  func TestSegmentMerge(t *testing.T) {
    45  	var clock faketime.NullClock
    46  	id := stack.TransportEndpointID{}
    47  	seg1 := newOutgoingSegment(id, &clock, buffer.MakeWithView(buffer.NewViewSize(10)))
    48  	defer seg1.DecRef()
    49  	seg2 := newOutgoingSegment(id, &clock, buffer.MakeWithView(buffer.NewViewSize(20)))
    50  	defer seg2.DecRef()
    51  
    52  	checkSegmentSize(t, "seg1", seg1, segmentSizeWants{
    53  		DataSize:   10,
    54  		SegMemSize: trueSegSize + 10,
    55  	})
    56  	checkSegmentSize(t, "seg2", seg2, segmentSizeWants{
    57  		DataSize:   20,
    58  		SegMemSize: trueSegSize + 20,
    59  	})
    60  
    61  	seg1.merge(seg2)
    62  
    63  	checkSegmentSize(t, "seg1", seg1, segmentSizeWants{
    64  		DataSize:   30,
    65  		SegMemSize: trueSegSize + 30,
    66  	})
    67  	checkSegmentSize(t, "seg2", seg2, segmentSizeWants{
    68  		DataSize:   0,
    69  		SegMemSize: trueSegSize,
    70  	})
    71  }