TUN-8762: fix argument order when invoking tracert and modify network info output parsing.

## Summary

The windows code path has three bugs:

* the -4 and -6 option cannot be passed in the last position
* since there are some lines in the command output that are not parsable the collection fails to parse any kind of output
* the timeout hop is not correctly parsed

This PR also guards the parsing code against empty domains

Closes TUN-8762
This commit is contained in:
Luis Neto 2024-12-03 04:56:28 -08:00
parent 65786597cc
commit 1ef109c042
6 changed files with 186 additions and 47 deletions

View File

@ -2,11 +2,14 @@ package diagnostic
import (
"context"
"errors"
"time"
)
const MicrosecondsFactor = 1000.0
var ErrEmptyDomain = errors.New("domain must not be empty")
// For now only support ICMP is provided.
type IPVersion int

View File

@ -68,7 +68,11 @@ func DecodeLine(text string) (*Hop, error) {
rtts = append(rtts, time.Duration(rtt*MicrosecondsFactor))
}
}
domain, _ = strings.CutSuffix(domain, " ")
if domain == "" {
return nil, ErrEmptyDomain
}
return NewHop(uint8(index), domain, rtts), nil
}

View File

@ -20,23 +20,68 @@ func TestDecode(t *testing.T) {
name string
text string
expectedHops []*diagnostic.Hop
expectErr bool
}{
{
"repeated hop index parse failure",
`1 172.68.101.121 (172.68.101.121) 12.874 ms 15.517 ms 15.311 ms
2 172.68.101.121 (172.68.101.121) 12.874 ms 15.517 ms 15.311 ms
someletters * * *`,
nil,
true,
someletters * * *
4 172.68.101.121 (172.68.101.121) 12.874 ms 15.517 ms 15.311 ms `,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
diagnostic.NewHop(
uint8(2),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
diagnostic.NewHop(
uint8(4),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
},
},
{
"hop index parse failure",
`1 172.68.101.121 (172.68.101.121) 12.874 ms 15.517 ms 15.311 ms
2 172.68.101.121 (172.68.101.121) 12.874 ms 15.517 ms 15.311 ms
someletters 8.8.8.8 8.8.8.9 abc ms 0.456 ms 0.789 ms`,
nil,
true,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
diagnostic.NewHop(
uint8(2),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
},
},
{
"missing rtt",
@ -61,7 +106,6 @@ someletters 8.8.8.8 8.8.8.9 abc ms 0.456 ms 0.789 ms`,
},
),
},
false,
},
{
"simple example ipv4",
@ -89,7 +133,6 @@ someletters 8.8.8.8 8.8.8.9 abc ms 0.456 ms 0.789 ms`,
),
diagnostic.NewTimeoutHop(uint8(3)),
},
false,
},
{
"simple example ipv6",
@ -115,7 +158,6 @@ someletters 8.8.8.8 8.8.8.9 abc ms 0.456 ms 0.789 ms`,
},
),
},
false,
},
}
@ -124,12 +166,8 @@ someletters 8.8.8.8 8.8.8.9 abc ms 0.456 ms 0.789 ms`,
t.Parallel()
hops, err := diagnostic.Decode(strings.NewReader(test.text), diagnostic.DecodeLine)
if test.expectErr {
require.Error(t, err)
} else {
require.NoError(t, err)
assert.Equal(t, test.expectedHops, hops)
}
require.NoError(t, err)
assert.Equal(t, test.expectedHops, hops)
})
}
}

View File

@ -10,7 +10,7 @@ import (
type DecodeLineFunc func(text string) (*Hop, error)
func decodeNetworkOutputToFile(command *exec.Cmd, fn DecodeLineFunc) ([]*Hop, string, error) {
func decodeNetworkOutputToFile(command *exec.Cmd, decodeLine DecodeLineFunc) ([]*Hop, string, error) {
stdout, err := command.StdoutPipe()
if err != nil {
return nil, "", fmt.Errorf("error piping traceroute's output: %w", err)
@ -26,32 +26,41 @@ func decodeNetworkOutputToFile(command *exec.Cmd, fn DecodeLineFunc) ([]*Hop, st
// otherwise the process can become a zombie
buf := bytes.NewBuffer([]byte{})
tee := io.TeeReader(stdout, buf)
hops, err := Decode(tee, fn)
hops, err := Decode(tee, decodeLine)
// regardless of success of the decoding
// consume all output to have available in buf
_, _ = io.ReadAll(tee)
if werr := command.Wait(); werr != nil {
return nil, "", fmt.Errorf("error finishing traceroute: %w", werr)
}
if err != nil {
// consume all output to have available in buf
io.ReadAll(tee)
// This is already a TracerouteError no need to wrap it
return nil, buf.String(), err
}
return hops, "", nil
}
func Decode(reader io.Reader, fn DecodeLineFunc) ([]*Hop, error) {
func Decode(reader io.Reader, decodeLine DecodeLineFunc) ([]*Hop, error) {
scanner := bufio.NewScanner(reader)
scanner.Split(bufio.ScanLines)
var hops []*Hop
for scanner.Scan() {
text := scanner.Text()
hop, err := fn(text)
if text == "" {
continue
}
hop, err := decodeLine(text)
if err != nil {
return nil, fmt.Errorf("error decoding output line: %w", err)
// This continue is here on the error case because there are lines at the start and end
// that may not be parsable. (check windows tracert output)
// The skip is here because aside from the start and end lines the other lines should
// always be parsable without errors.
continue
}
hops = append(hops, hop)

View File

@ -14,7 +14,13 @@ import (
type NetworkCollectorImpl struct{}
func (tracer *NetworkCollectorImpl) Collect(ctx context.Context, options TraceOptions) ([]*Hop, string, error) {
ipversion := "-4"
if !options.useV4 {
ipversion = "-6"
}
args := []string{
ipversion,
"-w",
strconv.FormatInt(int64(options.timeout.Seconds()), 10),
"-h",
@ -23,17 +29,14 @@ func (tracer *NetworkCollectorImpl) Collect(ctx context.Context, options TraceOp
"-d",
options.address,
}
if options.useV4 {
args = append(args, "-4")
} else {
args = append(args, "-6")
}
command := exec.CommandContext(ctx, "tracert.exe", args...)
return decodeNetworkOutputToFile(command, DecodeLine)
}
func DecodeLine(text string) (*Hop, error) {
const requestTimedOut = "Request timed out."
fields := strings.Fields(text)
parts := []string{}
filter := func(s string) bool { return s != "*" && s != "ms" }
@ -49,10 +52,6 @@ func DecodeLine(text string) (*Hop, error) {
return nil, fmt.Errorf("couldn't parse index from timeout hop: %w", err)
}
if len(parts) == 1 {
return NewTimeoutHop(uint8(index)), nil
}
domain := ""
rtts := []time.Duration{}
@ -66,6 +65,17 @@ func DecodeLine(text string) (*Hop, error) {
rtts = append(rtts, time.Duration(rtt*MicrosecondsFactor))
}
}
domain, _ = strings.CutSuffix(domain, " ")
// If the domain is equal to "Request timed out." then we build a
// timeout hop.
if domain == requestTimedOut {
return NewTimeoutHop(uint8(index)), nil
}
if domain == "" {
return nil, ErrEmptyDomain
}
return NewHop(uint8(index), domain, rtts), nil
}

View File

@ -20,23 +20,105 @@ func TestDecode(t *testing.T) {
name string
text string
expectedHops []*diagnostic.Hop
expectErr bool
}{
{
"tracert output",
`
Tracing route to region2.v2.argotunnel.com [198.41.200.73]
over a maximum of 5 hops:
1 10 ms <1 ms 1 ms 192.168.64.1
2 27 ms 14 ms 5 ms 192.168.1.254
3 * * * Request timed out.
4 * * * Request timed out.
5 27 ms 5 ms 5 ms 195.8.30.245
Trace complete.
`,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
"192.168.64.1",
[]time.Duration{
time.Duration(10000),
time.Duration(1000),
time.Duration(1000),
},
),
diagnostic.NewHop(
uint8(2),
"192.168.1.254",
[]time.Duration{
time.Duration(27000),
time.Duration(14000),
time.Duration(5000),
},
),
diagnostic.NewTimeoutHop(uint8(3)),
diagnostic.NewTimeoutHop(uint8(4)),
diagnostic.NewHop(
uint8(5),
"195.8.30.245",
[]time.Duration{
time.Duration(27000),
time.Duration(5000),
time.Duration(5000),
},
),
},
},
{
"repeated hop index parse failure",
`1 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
2 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
someletters * * *`,
nil,
true,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
diagnostic.NewHop(
uint8(2),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
},
},
{
"hop index parse failure",
`1 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
2 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
someletters abc ms 0.456 ms 0.789 ms 8.8.8.8 8.8.8.9`,
nil,
true,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
diagnostic.NewHop(
uint8(2),
"172.68.101.121 (172.68.101.121)",
[]time.Duration{
time.Duration(12874),
time.Duration(15517),
time.Duration(15311),
},
),
},
},
{
"missing rtt",
@ -61,13 +143,12 @@ someletters abc ms 0.456 ms 0.789 ms 8.8.8.8 8.8.8.9`,
},
),
},
false,
},
{
"simple example ipv4",
`1 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
2 12.874 ms 15.517 ms 15.311 ms 172.68.101.121 (172.68.101.121)
3 * * *`,
3 * * * Request timed out.`,
[]*diagnostic.Hop{
diagnostic.NewHop(
uint8(1),
@ -89,7 +170,6 @@ someletters abc ms 0.456 ms 0.789 ms 8.8.8.8 8.8.8.9`,
),
diagnostic.NewTimeoutHop(uint8(3)),
},
false,
},
{
"simple example ipv6",
@ -115,7 +195,6 @@ someletters abc ms 0.456 ms 0.789 ms 8.8.8.8 8.8.8.9`,
},
),
},
false,
},
}
@ -124,12 +203,8 @@ someletters abc ms 0.456 ms 0.789 ms 8.8.8.8 8.8.8.9`,
t.Parallel()
hops, err := diagnostic.Decode(strings.NewReader(test.text), diagnostic.DecodeLine)
if test.expectErr {
require.Error(t, err)
} else {
require.NoError(t, err)
assert.Equal(t, test.expectedHops, hops)
}
require.NoError(t, err)
assert.Equal(t, test.expectedHops, hops)
})
}
}