From 4c402a60121fff7730fe6eb9a31287e29471b292 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Fri, 20 Mar 2020 17:55:33 +0100
Subject: [PATCH] Revert "Implement pN load balancing strategy (#1188)"

This reverts commit 014a75c0ec9fd4a6c84c030b88e2c12cf71d7d16.
---
 dnscrypt-proxy/config.go                   | 13 ++++---------
 dnscrypt-proxy/example-dnscrypt-proxy.toml |  1 -
 dnscrypt-proxy/serversInfo.go              | 19 ++++++++++++-------
 3 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/dnscrypt-proxy/config.go b/dnscrypt-proxy/config.go
index d0d91f3b..5c8abbea 100644
--- a/dnscrypt-proxy/config.go
+++ b/dnscrypt-proxy/config.go
@@ -363,22 +363,17 @@ func ConfigLoad(proxy *Proxy, flags *ConfigFlags) error {
 	switch strings.ToLower(config.LBStrategy) {
 	case "":
 		// default
+	case "p2":
+		lbStrategy = LBStrategyP2
 	case "ph":
 		lbStrategy = LBStrategyPH
 	case "fastest":
 	case "first":
-		lbStrategy = LBStrategy(1)
+		lbStrategy = LBStrategyFirst
 	case "random":
 		lbStrategy = LBStrategyRandom
-
 	default:
-		n, err := strconv.ParseUint(strings.TrimPrefix(config.LBStrategy, "p"), 10, 64)
-
-		if err == nil && n >= 1 {
-			lbStrategy = LBStrategy(n)
-		} else {
-			dlog.Warnf("Unknown load balancing strategy: [%s]", config.LBStrategy)
-		}
+		dlog.Warnf("Unknown load balancing strategy: [%s]", config.LBStrategy)
 	}
 	proxy.serversInfo.lbStrategy = lbStrategy
 	proxy.serversInfo.lbEstimator = config.LBEstimator
diff --git a/dnscrypt-proxy/example-dnscrypt-proxy.toml b/dnscrypt-proxy/example-dnscrypt-proxy.toml
index 041deb76..b4ba6910 100644
--- a/dnscrypt-proxy/example-dnscrypt-proxy.toml
+++ b/dnscrypt-proxy/example-dnscrypt-proxy.toml
@@ -126,7 +126,6 @@ keepalive = 30
 
 
 ## Load-balancing strategy: 'p2' (default), 'ph', 'first' or 'random'
-## Use pN where N is a positive number to choose between N first fastest servers.
 
 # lb_strategy = 'p2'
 
diff --git a/dnscrypt-proxy/serversInfo.go b/dnscrypt-proxy/serversInfo.go
index 4a79436a..6327f7c0 100644
--- a/dnscrypt-proxy/serversInfo.go
+++ b/dnscrypt-proxy/serversInfo.go
@@ -65,11 +65,14 @@ type ServerInfo struct {
 type LBStrategy int
 
 const (
-	LBStrategyRandom = LBStrategy(0)
-	LBStrategyPH     = LBStrategy(-1)
+	LBStrategyNone = LBStrategy(iota)
+	LBStrategyP2
+	LBStrategyPH
+	LBStrategyFirst
+	LBStrategyRandom
 )
 
-const DefaultLBStrategy = LBStrategy(2)
+const DefaultLBStrategy = LBStrategyP2
 
 type ServersInfo struct {
 	sync.RWMutex
@@ -208,12 +211,14 @@ func (serversInfo *ServersInfo) getOne() *ServerInfo {
 	}
 	var candidate int
 	switch serversInfo.lbStrategy {
-	case -1: // First half
+	case LBStrategyFirst:
+		candidate = 0
+	case LBStrategyPH:
 		candidate = rand.Intn(Max(Min(serversCount, 2), serversCount/2))
-	case 0: // Random
+	case LBStrategyRandom:
 		candidate = rand.Intn(serversCount)
-	default: // First N
-		candidate = rand.Intn(int(serversInfo.lbStrategy)) % serversCount
+	default:
+		candidate = rand.Intn(Min(serversCount, 2))
 	}
 	serverInfo := serversInfo.inner[candidate]
 	dlog.Debugf("Using candidate [%s] RTT: %d", (*serverInfo).Name, int((*serverInfo).rtt.Value()))