cmd/derpprobe: also do UDP STUN probing

Updates #3049

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/3051/head
Brad Fitzpatrick 3 years ago
parent a2e1e5d909
commit 13ef8e3c06

@ -15,6 +15,7 @@ import (
"html" "html"
"io" "io"
"log" "log"
"net"
"net/http" "net/http"
"sort" "sort"
"sync" "sync"
@ -22,6 +23,7 @@ import (
"tailscale.com/derp" "tailscale.com/derp"
"tailscale.com/derp/derphttp" "tailscale.com/derp/derphttp"
"tailscale.com/net/stun"
"tailscale.com/tailcfg" "tailscale.com/tailcfg"
"tailscale.com/types/key" "tailscale.com/types/key"
) )
@ -67,22 +69,27 @@ func getOverallStatus() (o overallStatus) {
if age := now.Sub(lastDERPMapAt); age > time.Minute { if age := now.Sub(lastDERPMapAt); age > time.Minute {
o.addBadf("DERPMap hasn't been successfully refreshed in %v", age.Round(time.Second)) o.addBadf("DERPMap hasn't been successfully refreshed in %v", age.Round(time.Second))
} }
addPairMeta := func(pair nodePair) {
st, ok := state[pair]
age := now.Sub(st.at).Round(time.Second)
switch {
case !ok:
o.addBadf("no state for %v", pair)
case st.err != nil:
o.addBadf("%v: %v", pair, st.err)
case age > 90*time.Second:
o.addBadf("%v: update is %v old", pair, age)
default:
o.addGoodf("%v: %v, %v ago", pair, st.latency.Round(time.Millisecond), age)
}
}
for _, reg := range sortedRegions(lastDERPMap) { for _, reg := range sortedRegions(lastDERPMap) {
for _, from := range reg.Nodes { for _, from := range reg.Nodes {
addPairMeta(nodePair{"UDP", from.Name})
for _, to := range reg.Nodes { for _, to := range reg.Nodes {
pair := nodePair{from.Name, to.Name} addPairMeta(nodePair{from.Name, to.Name})
st, ok := state[pair]
age := now.Sub(st.at).Round(time.Second)
switch {
case !ok:
o.addBadf("no state for %v", pair)
case st.err != nil:
o.addBadf("%v: %v", pair, st.err)
case age > 90*time.Second:
o.addBadf("%v: update is %v old", pair, age)
default:
o.addGoodf("%v: %v, %v ago", pair, st.latency.Round(time.Millisecond), age)
}
} }
} }
} }
@ -117,7 +124,8 @@ func sortedRegions(dm *tailcfg.DERPMap) []*tailcfg.DERPRegion {
} }
type nodePair struct { type nodePair struct {
from, to string // DERPNode.Name from string // DERPNode.Name, or "UDP" for a STUN query to 'to'
to string // DERPNode.Name
} }
func (p nodePair) String() string { return fmt.Sprintf("(%s→%s)", p.from, p.to) } func (p nodePair) String() string { return fmt.Sprintf("(%s→%s)", p.from, p.to) }
@ -177,6 +185,8 @@ func probe() error {
go func() { go func() {
defer wg.Done() defer wg.Done()
for _, from := range reg.Nodes { for _, from := range reg.Nodes {
latency, err := probeUDP(ctx, dm, from)
setState(nodePair{"UDP", from.Name}, latency, err)
for _, to := range reg.Nodes { for _, to := range reg.Nodes {
latency, err := probeNodePair(ctx, dm, from, to) latency, err := probeNodePair(ctx, dm, from, to)
setState(nodePair{from.Name, to.Name}, latency, err) setState(nodePair{from.Name, to.Name}, latency, err)
@ -189,6 +199,65 @@ func probe() error {
return ctx.Err() return ctx.Err()
} }
func probeUDP(ctx context.Context, dm *tailcfg.DERPMap, n *tailcfg.DERPNode) (latency time.Duration, err error) {
pc, err := net.ListenPacket("udp", ":0")
if err != nil {
return 0, err
}
defer pc.Close()
uc := pc.(*net.UDPConn)
tx := stun.NewTxID()
req := stun.Request(tx)
for _, ipStr := range []string{n.IPv4, n.IPv6} {
if ipStr == "" {
continue
}
port := n.STUNPort
if port == -1 {
continue
}
if port == 0 {
port = 3478
}
for {
ip := net.ParseIP(ipStr)
_, err := uc.WriteToUDP(req, &net.UDPAddr{IP: ip, Port: port})
if err != nil {
return 0, err
}
buf := make([]byte, 1500)
uc.SetReadDeadline(time.Now().Add(2 * time.Second))
t0 := time.Now()
n, _, err := uc.ReadFromUDP(buf)
d := time.Since(t0)
if err != nil {
if ctx.Err() != nil {
return 0, fmt.Errorf("timeout reading from %v: %v", ip)
}
if d < time.Second {
return 0, fmt.Errorf("error reading from %v: %v", ip, err)
}
time.Sleep(100 * time.Millisecond)
continue
}
txBack, _, _, err := stun.ParseResponse(buf[:n])
if err != nil {
return 0, fmt.Errorf("parsing STUN response from %v: %v", ip, err)
}
if txBack != tx {
return 0, fmt.Errorf("read wrong tx back from %v", ip)
}
if latency == 0 || d < latency {
latency = d
}
break
}
}
return latency, nil
}
func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.DERPNode) (latency time.Duration, err error) { func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.DERPNode) (latency time.Duration, err error) {
// The passed in context is a minute for the whole region. The // The passed in context is a minute for the whole region. The
// idea is that each node pair in the region will be done // idea is that each node pair in the region will be done

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