p2p/netutil: new package for network utilities

The new package contains three things for now:

- IP network list parsing and matching
- The WSAEMSGSIZE workaround, which is duplicated in p2p/discover and
  p2p/discv5.
This commit is contained in:
Felix Lange 2016-11-21 18:11:21 +01:00
parent 04edbb0703
commit 1d80155d5e
6 changed files with 503 additions and 0 deletions

25
p2p/netutil/error.go Normal file
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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package netutil
// IsTemporaryError checks whether the given error should be considered temporary.
func IsTemporaryError(err error) bool {
tempErr, ok := err.(interface {
Temporary() bool
})
return ok && tempErr.Temporary() || isPacketTooBig(err)
}

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p2p/netutil/error_test.go Normal file
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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package netutil
import (
"net"
"testing"
"time"
)
// This test checks that isPacketTooBig correctly identifies
// errors that result from receiving a UDP packet larger
// than the supplied receive buffer.
func TestIsPacketTooBig(t *testing.T) {
listener, err := net.ListenPacket("udp", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
defer listener.Close()
sender, err := net.Dial("udp", listener.LocalAddr().String())
if err != nil {
t.Fatal(err)
}
defer sender.Close()
sendN := 1800
recvN := 300
for i := 0; i < 20; i++ {
go func() {
buf := make([]byte, sendN)
for i := range buf {
buf[i] = byte(i)
}
sender.Write(buf)
}()
buf := make([]byte, recvN)
listener.SetDeadline(time.Now().Add(1 * time.Second))
n, _, err := listener.ReadFrom(buf)
if err != nil {
if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
continue
}
if !isPacketTooBig(err) {
t.Fatalf("unexpected read error: %v", err)
}
continue
}
if n != recvN {
t.Fatalf("short read: %d, want %d", n, recvN)
}
for i := range buf {
if buf[i] != byte(i) {
t.Fatalf("error in pattern")
break
}
}
}
}

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p2p/netutil/net.go Normal file
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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package netutil contains extensions to the net package.
package netutil
import (
"errors"
"net"
"strings"
)
var lan4, lan6, special4, special6 Netlist
func init() {
// Lists from RFC 5735, RFC 5156,
// https://www.iana.org/assignments/iana-ipv4-special-registry/
lan4.Add("0.0.0.0/8") // "This" network
lan4.Add("10.0.0.0/8") // Private Use
lan4.Add("172.16.0.0/12") // Private Use
lan4.Add("192.168.0.0/16") // Private Use
lan6.Add("fe80::/10") // Link-Local
lan6.Add("fc00::/7") // Unique-Local
special4.Add("192.0.0.0/29") // IPv4 Service Continuity
special4.Add("192.0.0.9/32") // PCP Anycast
special4.Add("192.0.0.170/32") // NAT64/DNS64 Discovery
special4.Add("192.0.0.171/32") // NAT64/DNS64 Discovery
special4.Add("192.0.2.0/24") // TEST-NET-1
special4.Add("192.31.196.0/24") // AS112
special4.Add("192.52.193.0/24") // AMT
special4.Add("192.88.99.0/24") // 6to4 Relay Anycast
special4.Add("192.175.48.0/24") // AS112
special4.Add("198.18.0.0/15") // Device Benchmark Testing
special4.Add("198.51.100.0/24") // TEST-NET-2
special4.Add("203.0.113.0/24") // TEST-NET-3
special4.Add("255.255.255.255/32") // Limited Broadcast
// http://www.iana.org/assignments/iana-ipv6-special-registry/
special6.Add("100::/64")
special6.Add("2001::/32")
special6.Add("2001:1::1/128")
special6.Add("2001:2::/48")
special6.Add("2001:3::/32")
special6.Add("2001:4:112::/48")
special6.Add("2001:5::/32")
special6.Add("2001:10::/28")
special6.Add("2001:20::/28")
special6.Add("2001:db8::/32")
special6.Add("2002::/16")
}
// Netlist is a list of IP networks.
type Netlist []net.IPNet
// ParseNetlist parses a comma-separated list of CIDR masks.
// Whitespace and extra commas are ignored.
func ParseNetlist(s string) (*Netlist, error) {
ws := strings.NewReplacer(" ", "", "\n", "", "\t", "")
masks := strings.Split(ws.Replace(s), ",")
l := make(Netlist, 0)
for _, mask := range masks {
if mask == "" {
continue
}
_, n, err := net.ParseCIDR(mask)
if err != nil {
return nil, err
}
l = append(l, *n)
}
return &l, nil
}
// Add parses a CIDR mask and appends it to the list. It panics for invalid masks and is
// intended to be used for setting up static lists.
func (l *Netlist) Add(cidr string) {
_, n, err := net.ParseCIDR(cidr)
if err != nil {
panic(err)
}
*l = append(*l, *n)
}
// Contains reports whether the given IP is contained in the list.
func (l *Netlist) Contains(ip net.IP) bool {
if l == nil {
return false
}
for _, net := range *l {
if net.Contains(ip) {
return true
}
}
return false
}
// IsLAN reports whether an IP is a local network address.
func IsLAN(ip net.IP) bool {
if ip.IsLoopback() {
return true
}
if v4 := ip.To4(); v4 != nil {
return lan4.Contains(v4)
}
return lan6.Contains(ip)
}
// IsSpecialNetwork reports whether an IP is located in a special-use network range
// This includes broadcast, multicast and documentation addresses.
func IsSpecialNetwork(ip net.IP) bool {
if ip.IsMulticast() {
return true
}
if v4 := ip.To4(); v4 != nil {
return special4.Contains(v4)
}
return special6.Contains(ip)
}
var (
errInvalid = errors.New("invalid IP")
errUnspecified = errors.New("zero address")
errSpecial = errors.New("special network")
errLoopback = errors.New("loopback address from non-loopback host")
errLAN = errors.New("LAN address from WAN host")
)
// CheckRelayIP reports whether an IP relayed from the given sender IP
// is a valid connection target.
//
// There are four rules:
// - Special network addresses are never valid.
// - Loopback addresses are OK if relayed by a loopback host.
// - LAN addresses are OK if relayed by a LAN host.
// - All other addresses are always acceptable.
func CheckRelayIP(sender, addr net.IP) error {
if len(addr) != net.IPv4len && len(addr) != net.IPv6len {
return errInvalid
}
if addr.IsUnspecified() {
return errUnspecified
}
if IsSpecialNetwork(addr) {
return errSpecial
}
if addr.IsLoopback() && !sender.IsLoopback() {
return errLoopback
}
if IsLAN(addr) && !IsLAN(sender) {
return errLAN
}
return nil
}

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p2p/netutil/net_test.go Normal file
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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package netutil
import (
"net"
"reflect"
"testing"
"github.com/davecgh/go-spew/spew"
)
func TestParseNetlist(t *testing.T) {
var tests = []struct {
input string
wantErr error
wantList *Netlist
}{
{
input: "",
wantList: &Netlist{},
},
{
input: "127.0.0.0/8",
wantErr: nil,
wantList: &Netlist{{IP: net.IP{127, 0, 0, 0}, Mask: net.CIDRMask(8, 32)}},
},
{
input: "127.0.0.0/44",
wantErr: &net.ParseError{Type: "CIDR address", Text: "127.0.0.0/44"},
},
{
input: "127.0.0.0/16, 23.23.23.23/24,",
wantList: &Netlist{
{IP: net.IP{127, 0, 0, 0}, Mask: net.CIDRMask(16, 32)},
{IP: net.IP{23, 23, 23, 0}, Mask: net.CIDRMask(24, 32)},
},
},
}
for _, test := range tests {
l, err := ParseNetlist(test.input)
if !reflect.DeepEqual(err, test.wantErr) {
t.Errorf("%q: got error %q, want %q", test.input, err, test.wantErr)
continue
}
if !reflect.DeepEqual(l, test.wantList) {
spew.Dump(l)
spew.Dump(test.wantList)
t.Errorf("%q: got %v, want %v", test.input, l, test.wantList)
}
}
}
func TestNilNetListContains(t *testing.T) {
var list *Netlist
checkContains(t, list.Contains, nil, []string{"1.2.3.4"})
}
func TestIsLAN(t *testing.T) {
checkContains(t, IsLAN,
[]string{ // included
"0.0.0.0",
"0.2.0.8",
"127.0.0.1",
"10.0.1.1",
"10.22.0.3",
"172.31.252.251",
"192.168.1.4",
"fe80::f4a1:8eff:fec5:9d9d",
"febf::ab32:2233",
"fc00::4",
},
[]string{ // excluded
"192.0.2.1",
"1.0.0.0",
"172.32.0.1",
"fec0::2233",
},
)
}
func TestIsSpecialNetwork(t *testing.T) {
checkContains(t, IsSpecialNetwork,
[]string{ // included
"192.0.2.1",
"192.0.2.44",
"2001:db8:85a3:8d3:1319:8a2e:370:7348",
"255.255.255.255",
"224.0.0.22", // IPv4 multicast
"ff05::1:3", // IPv6 multicast
},
[]string{ // excluded
"192.0.3.1",
"1.0.0.0",
"172.32.0.1",
"fec0::2233",
},
)
}
func checkContains(t *testing.T, fn func(net.IP) bool, inc, exc []string) {
for _, s := range inc {
if !fn(parseIP(s)) {
t.Error("returned false for included address", s)
}
}
for _, s := range exc {
if fn(parseIP(s)) {
t.Error("returned true for excluded address", s)
}
}
}
func parseIP(s string) net.IP {
ip := net.ParseIP(s)
if ip == nil {
panic("invalid " + s)
}
return ip
}
func TestCheckRelayIP(t *testing.T) {
tests := []struct {
sender, addr string
want error
}{
{"127.0.0.1", "0.0.0.0", errUnspecified},
{"192.168.0.1", "0.0.0.0", errUnspecified},
{"23.55.1.242", "0.0.0.0", errUnspecified},
{"127.0.0.1", "255.255.255.255", errSpecial},
{"192.168.0.1", "255.255.255.255", errSpecial},
{"23.55.1.242", "255.255.255.255", errSpecial},
{"192.168.0.1", "127.0.2.19", errLoopback},
{"23.55.1.242", "192.168.0.1", errLAN},
{"127.0.0.1", "127.0.2.19", nil},
{"127.0.0.1", "192.168.0.1", nil},
{"127.0.0.1", "23.55.1.242", nil},
{"192.168.0.1", "192.168.0.1", nil},
{"192.168.0.1", "23.55.1.242", nil},
{"23.55.1.242", "23.55.1.242", nil},
}
for _, test := range tests {
err := CheckRelayIP(parseIP(test.sender), parseIP(test.addr))
if err != test.want {
t.Errorf("%s from %s: got %q, want %q", test.addr, test.sender, err, test.want)
}
}
}
func BenchmarkCheckRelayIP(b *testing.B) {
sender := parseIP("23.55.1.242")
addr := parseIP("23.55.1.2")
for i := 0; i < b.N; i++ {
CheckRelayIP(sender, addr)
}
}

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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//+build !windows
package netutil
// isPacketTooBig reports whether err indicates that a UDP packet didn't
// fit the receive buffer. There is no such error on
// non-Windows platforms.
func isPacketTooBig(err error) bool {
return false
}

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// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//+build windows
package netutil
import (
"net"
"os"
"syscall"
)
const _WSAEMSGSIZE = syscall.Errno(10040)
// isPacketTooBig reports whether err indicates that a UDP packet didn't
// fit the receive buffer. On Windows, WSARecvFrom returns
// code WSAEMSGSIZE and no data if this happens.
func isPacketTooBig(err error) bool {
if opErr, ok := err.(*net.OpError); ok {
if scErr, ok := opErr.Err.(*os.SyscallError); ok {
return scErr.Err == _WSAEMSGSIZE
}
return opErr.Err == _WSAEMSGSIZE
}
return false
}