github.com/Steality/go-ethereum@v1.9.7/p2p/netutil/error_test.go (about)

     1  // Copyright 2016 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package netutil
    18  
    19  import (
    20  	"net"
    21  	"testing"
    22  	"time"
    23  )
    24  
    25  // This test checks that isPacketTooBig correctly identifies
    26  // errors that result from receiving a UDP packet larger
    27  // than the supplied receive buffer.
    28  func TestIsPacketTooBig(t *testing.T) {
    29  	listener, err := net.ListenPacket("udp", "127.0.0.1:0")
    30  	if err != nil {
    31  		t.Fatal(err)
    32  	}
    33  	defer listener.Close()
    34  	sender, err := net.Dial("udp", listener.LocalAddr().String())
    35  	if err != nil {
    36  		t.Fatal(err)
    37  	}
    38  	defer sender.Close()
    39  
    40  	sendN := 1800
    41  	recvN := 300
    42  	for i := 0; i < 20; i++ {
    43  		go func() {
    44  			buf := make([]byte, sendN)
    45  			for i := range buf {
    46  				buf[i] = byte(i)
    47  			}
    48  			sender.Write(buf)
    49  		}()
    50  
    51  		buf := make([]byte, recvN)
    52  		listener.SetDeadline(time.Now().Add(1 * time.Second))
    53  		n, _, err := listener.ReadFrom(buf)
    54  		if err != nil {
    55  			if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
    56  				continue
    57  			}
    58  			if !isPacketTooBig(err) {
    59  				t.Fatalf("unexpected read error: %v", err)
    60  			}
    61  			continue
    62  		}
    63  		if n != recvN {
    64  			t.Fatalf("short read: %d, want %d", n, recvN)
    65  		}
    66  		for i := range buf {
    67  			if buf[i] != byte(i) {
    68  				t.Fatalf("error in pattern")
    69  				break
    70  			}
    71  		}
    72  	}
    73  }