From 6a934639524bf1e54686d038f526bc2d0d40a71b Mon Sep 17 00:00:00 2001
From: Josh Bleecher Snyder <josh@tailscale.com>
Date: Fri, 6 Aug 2021 15:30:59 -0700
Subject: [PATCH] move code around, add benchmark

note that this splits a mutex access in two
---
 wgengine/userspace.go      | 38 +++++++++++++--------
 wgengine/userspace_test.go | 67 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+), 14 deletions(-)

diff --git a/wgengine/userspace.go b/wgengine/userspace.go
index 4a22c888a..5e237807f 100644
--- a/wgengine/userspace.go
+++ b/wgengine/userspace.go
@@ -921,11 +921,6 @@ func (e *userspaceEngine) getStatus() (*Status, error) {
 		errc <- err
 	}()
 
-	pp := make(map[wgkey.Key]*ipnstate.PeerStatusLite)
-	p := &ipnstate.PeerStatusLite{}
-
-	var hst1, hst2, n int64
-
 	br := e.statusBufioReader
 	if br != nil {
 		br.Reset(pr)
@@ -933,6 +928,29 @@ func (e *userspaceEngine) getStatus() (*Status, error) {
 		br = bufio.NewReaderSize(pr, 1<<10)
 		e.statusBufioReader = br
 	}
+
+	peers, err := e.getPeerStatusLite(br)
+	if err != nil {
+		return nil, err
+	}
+	if err := <-errc; err != nil {
+		return nil, fmt.Errorf("IpcGetOperation: %v", err)
+	}
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	return &Status{
+		LocalAddrs: append([]tailcfg.Endpoint(nil), e.endpoints...),
+		Peers:      peers,
+		DERPs:      derpConns,
+	}, nil
+}
+
+func (e *userspaceEngine) getPeerStatusLite(br *bufio.Reader) ([]ipnstate.PeerStatusLite, error) {
+	pp := make(map[wgkey.Key]*ipnstate.PeerStatusLite)
+	p := &ipnstate.PeerStatusLite{}
+
+	var hst1, hst2, n int64
+
 	for {
 		line, err := br.ReadSlice('\n')
 		if err == io.EOF {
@@ -986,9 +1004,6 @@ func (e *userspaceEngine) getStatus() (*Status, error) {
 			} // else leave at time.IsZero()
 		}
 	}
-	if err := <-errc; err != nil {
-		return nil, fmt.Errorf("IpcGetOperation: %v", err)
-	}
 
 	e.mu.Lock()
 	defer e.mu.Unlock()
@@ -999,12 +1014,7 @@ func (e *userspaceEngine) getStatus() (*Status, error) {
 			peers = append(peers, *p)
 		}
 	}
-
-	return &Status{
-		LocalAddrs: append([]tailcfg.Endpoint(nil), e.endpoints...),
-		Peers:      peers,
-		DERPs:      derpConns,
-	}, nil
+	return peers, nil
 }
 
 func (e *userspaceEngine) RequestStatus() {
diff --git a/wgengine/userspace_test.go b/wgengine/userspace_test.go
index 39fcd9f5b..3d32c4b8a 100644
--- a/wgengine/userspace_test.go
+++ b/wgengine/userspace_test.go
@@ -5,9 +5,11 @@
 package wgengine
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 
 	"go4.org/mem"
@@ -17,6 +19,7 @@ import (
 	"tailscale.com/tailcfg"
 	"tailscale.com/tstime/mono"
 	"tailscale.com/types/key"
+	"tailscale.com/types/wgkey"
 	"tailscale.com/wgengine/router"
 	"tailscale.com/wgengine/wgcfg"
 )
@@ -252,3 +255,67 @@ func BenchmarkGenLocalAddrFunc(b *testing.B) {
 	})
 	b.Logf("x = %v", x)
 }
+
+func BenchmarkGetPeerStatusLite(b *testing.B) {
+	e := new(userspaceEngine)
+	br := bufio.NewReaderSize(nil, 1<<10)
+	parseKey := func(s string) wgkey.Key {
+		k, err := wgkey.ParseHex(s)
+		if err != nil {
+			b.Fatal(err)
+		}
+		return k
+	}
+	e.peerSequence = []wgkey.Key{
+		parseKey("0000000000000000000000000000000000000000000000000000000000000002"),
+		parseKey("0000000000000000000000000000000000000000000000000000000000000003"),
+		parseKey("0000000000000000000000000000000000000000000000000000000000000004"),
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		br.Reset(strings.NewReader(sampleStatus))
+		_, err := e.getPeerStatusLite(br)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+const sampleStatus = `
+private_key=0000000000000000000000000000000000000000000000000000000000000001
+listen_port=50818
+public_key=0000000000000000000000000000000000000000000000000000000000000002
+preshared_key=0000000000000000000000000000000000000000000000000000000000000000
+protocol_version=1
+endpoint={"pk":"0000000000000000000000000000000000000000000000000000000000000002","dk":"discokey:0000000000000000000000000000000000000000000000000000000000000000","ipp":["139.162.81.125:41641"]}
+last_handshake_time_sec=1628288511
+last_handshake_time_nsec=993469000
+tx_bytes=272
+rx_bytes=272
+persistent_keepalive_interval=25
+allowed_ip=100.100.100.101/32
+allowed_ip=::2/128
+public_key=0000000000000000000000000000000000000000000000000000000000000003
+preshared_key=0000000000000000000000000000000000000000000000000000000000000000
+protocol_version=1
+endpoint={"pk":"0000000000000000000000000000000000000000000000000000000000000003","dk":"discokey:c6c0a1488ac6cb9e0103d056ca51387e33513d577b985e77c6ea075f76b27d35","ipp":null}
+last_handshake_time_sec=1628288511
+last_handshake_time_nsec=615842000
+tx_bytes=1300
+rx_bytes=92
+persistent_keepalive_interval=0
+allowed_ip=100.100.100.102/32
+allowed_ip=::3/128
+public_key=0000000000000000000000000000000000000000000000000000000000000004
+preshared_key=0000000000000000000000000000000000000000000000000000000000000000
+protocol_version=1
+endpoint={"pk":"0000000000000000000000000000000000000000000000000000000000000004","dk":"discokey:c6c0a1488ac6cb9e0103d056ca51387e33513d577b985e77c6ea075f76b27d35","ipp":null}
+last_handshake_time_sec=1628288511
+last_handshake_time_nsec=615842000
+tx_bytes=1300
+rx_bytes=92
+persistent_keepalive_interval=0
+allowed_ip=100.100.100.103/32
+allowed_ip=::4/128
+`