From 8494d3fdc10cbf6a8518ef3089298e783c38156c Mon Sep 17 00:00:00 2001
From: Peter Schultz <peter.schultz@classmarkets.com>
Date: Tue, 16 Jul 2019 17:05:03 +0200
Subject: [PATCH] Fix matching priority for host:port tuples (#675)

e566aaab reversed DNS names since they have
their most significant part at the front. Unfortunately it didn't
consider cases where the name is followed by a :port, making names
without port always take precedence over names with a port.

This patch changes the reverse function to ignores such port suffixes.

Signed-off-by: Peter Schultz <peter.schultz@classmarkets.com>
---
 route/table.go      | 27 +++++++++++++++++++--------
 route/table_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/route/table.go b/route/table.go
index f1d50eec3..67a5ca603 100644
--- a/route/table.go
+++ b/route/table.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 	"net/url"
 	"sort"
@@ -341,11 +342,11 @@ func (t Table) matchingHosts(req *http.Request) (hosts []string) {
 	// the correct result we need to reverse the strings, sort them and then
 	// reverse them again.
 	for i, h := range hosts {
-		hosts[i] = Reverse(h)
+		hosts[i] = ReverseHostPort(h)
 	}
 	sort.Sort(sort.Reverse(sort.StringSlice(hosts)))
 	for i, h := range hosts {
-		hosts[i] = Reverse(h)
+		hosts[i] = ReverseHostPort(h)
 	}
 	return
 }
@@ -368,15 +369,25 @@ func (t Table) matchingHostNoGlob(req *http.Request) (hosts []string) {
 	return
 }
 
-// Reverse returns its argument string reversed rune-wise left to right.
-//
-// taken from https://github.com/golang/example/blob/master/stringutil/reverse.go
-func Reverse(s string) string {
-	r := []rune(s)
+// ReverseHostPort returns its argument string reversed rune-wise left to
+// right. If s includes a port, only the host part is reversed.
+func ReverseHostPort(s string) string {
+	h, p, _ := net.SplitHostPort(s)
+	if h == "" {
+		h = s
+	}
+
+	// Taken from https://github.com/golang/example/blob/master/stringutil/reverse.go
+	r := []rune(h)
 	for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
 		r[i], r[j] = r[j], r[i]
 	}
-	return string(r)
+
+	if p == "" {
+		return string(r)
+	} else {
+		return net.JoinHostPort(string(r), p)
+	}
 }
 
 // Lookup finds a target url based on the current matcher and picker
diff --git a/route/table_test.go b/route/table_test.go
index fb621c8c0..86b260927 100644
--- a/route/table_test.go
+++ b/route/table_test.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"math"
 	"net/http"
+	"net/http/httptest"
 	"reflect"
 	"strconv"
 	"strings"
@@ -641,6 +642,32 @@ func TestTableLookup(t *testing.T) {
 	}
 }
 
+func TestTableLookup_656(t *testing.T) {
+	// A typical HTTPS redirect
+	s := `
+	route add my-service example.com:80/ https://example.com$path opts "redirect=301"
+	route add my-service example.com/ http://127.0.0.1:3000/
+	`
+
+	tbl, err := NewTable(bytes.NewBufferString(s))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest("GET", "http://example.com/foo", nil)
+	target := tbl.Lookup(req, "redirect", rrPicker, prefixMatcher, false)
+
+	if target == nil {
+		t.Fatal("No route match")
+	}
+	if got, want := target.RedirectCode, 301; got != want {
+		t.Errorf("target.RedirectCode = %d, want %d", got, want)
+	}
+	if got, want := fmt.Sprint(target.RedirectURL), "https://example.com/foo"; got != want {
+		t.Errorf("target.RedirectURL = %s, want %s", got, want)
+	}
+}
+
 func TestNewTableCustom(t *testing.T) {
 
 	var routes []RouteDef