Support Federation on a single machine (#8009)

When checking if federation is necessary, the code compares
the SRV record stored in etcd against the list of endpoints
that the MinIO server is exposing.  If there is an intersection
in this list the request is forwarded.

The SRV record includes both the host and the port, but the
intersection check previously only looked at the IP address.  This
would prevent federation from working in situations where the endpoint
IP is the same for multiple MinIO servers.  Some examples of where this
can occur are:
 - running mulitiple copies of MinIO on the same host
 - using multiple MinIO servers behind a NAT with port-forwarding

cmd/endpoint.go

@@ -720,18 +720,27 @@ func GetRemotePeers(endpoints EndpointList) []string {
 func updateDomainIPs(endPoints set.StringSet) {
 	ipList := set.NewStringSet()
 	for e := range endPoints {
-		host, _, err := net.SplitHostPort(e)
+		host, port, err := net.SplitHostPort(e)
 		if err != nil {
 			if strings.Contains(err.Error(), "missing port in address") {
 				host = e
+				port = globalMinioPort
 			} else {
 				continue
 			}
 		}
-		IPs, _ := getHostIP(host)
-		ipList = ipList.Union(IPs)
+		IPs, err := getHostIP(host)
+		if err != nil {
+			continue
+		}
+
+		IPsWithPort := IPs.ApplyFunc(func(ip string) string {
+			return net.JoinHostPort(ip, port)
+		})
+
+		ipList = ipList.Union(IPsWithPort)
 	}
 	globalDomainIPs = ipList.FuncMatch(func(ip string, matchString string) bool {
-		return !strings.HasPrefix(ip, "127.") || strings.HasPrefix(ip, "::1")
+		return !(strings.HasPrefix(ip, "127.") || strings.HasPrefix(ip, "::1") || strings.HasPrefix(ip, "[::1]"))
 	}, "")
 }

cmd/endpoint_test.go

@@ -25,6 +25,7 @@ import (
 	"testing"
 
 	"github.com/minio/cli"
+	"github.com/minio/minio-go/v6/pkg/set"
 )
 
 func TestSubOptimalEndpointInput(t *testing.T) {
@@ -444,3 +445,43 @@ func TestGetRemotePeers(t *testing.T) {
 		}
 	}
 }
+
+func TestUpdateDomainIPs(t *testing.T) {
+	tempGlobalMinioPort := globalMinioPort
+	defer func() {
+		globalMinioPort = tempGlobalMinioPort
+	}()
+	globalMinioPort = "9000"
+
+	tempGlobalDomainIPs := globalDomainIPs
+	defer func() {
+		globalDomainIPs = tempGlobalDomainIPs
+	}()
+
+	ipv4TestCases := []struct {
+		endPoints      set.StringSet
+		expectedResult set.StringSet
+	}{
+		{set.NewStringSet(), set.NewStringSet()},
+		{set.CreateStringSet("localhost"), set.NewStringSet()},
+		{set.CreateStringSet("localhost", "10.0.0.1"), set.CreateStringSet("10.0.0.1:9000")},
+		{set.CreateStringSet("localhost:9001", "10.0.0.1"), set.CreateStringSet("10.0.0.1:9000")},
+		{set.CreateStringSet("localhost", "10.0.0.1:9001"), set.CreateStringSet("10.0.0.1:9001")},
+		{set.CreateStringSet("localhost:9000", "10.0.0.1:9001"), set.CreateStringSet("10.0.0.1:9001")},
+
+		{set.CreateStringSet("10.0.0.1", "10.0.0.2"), set.CreateStringSet("10.0.0.1:9000", "10.0.0.2:9000")},
+		{set.CreateStringSet("10.0.0.1:9001", "10.0.0.2"), set.CreateStringSet("10.0.0.1:9001", "10.0.0.2:9000")},
+		{set.CreateStringSet("10.0.0.1", "10.0.0.2:9002"), set.CreateStringSet("10.0.0.1:9000", "10.0.0.2:9002")},
+		{set.CreateStringSet("10.0.0.1:9001", "10.0.0.2:9002"), set.CreateStringSet("10.0.0.1:9001", "10.0.0.2:9002")},
+	}
+
+	for _, testCase := range ipv4TestCases {
+		globalDomainIPs = nil
+
+		updateDomainIPs(testCase.endPoints)
+
+		if !testCase.expectedResult.Equals(globalDomainIPs) {
+			t.Fatalf("error: expected = %s, got = %s", testCase.expectedResult, globalDomainIPs)
+		}
+	}
+}

cmd/object-api-utils.go

@@ -319,7 +319,7 @@ func isMinioReservedBucket(bucketName string) bool {
 func getHostsSlice(records []dns.SrvRecord) []string {
 	var hosts []string
 	for _, r := range records {
-		hosts = append(hosts, r.Host)
+		hosts = append(hosts, net.JoinHostPort(r.Host, fmt.Sprintf("%d", r.Port)))
 	}
 	return hosts
 }

pkg/dns/etcd_dns.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net"
 	"sort"
 	"strconv"
 	"strings"
@@ -215,9 +216,20 @@ func NewCoreDNS(domainNames []string, domainIPs set.StringSet, domainPort string
 		return nil, err
 	}
 
+	// strip ports off of domainIPs
+	domainIPsWithoutPorts := domainIPs.ApplyFunc(func(ip string) string {
+		host, _, err := net.SplitHostPort(ip)
+		if err != nil {
+			if strings.Contains(err.Error(), "missing port in address") {
+				host = ip
+			}
+		}
+		return host
+	})
+
 	return &coreDNS{
 		domainNames: domainNames,
-		domainIPs:   domainIPs,
+		domainIPs:   domainIPsWithoutPorts,
 		domainPort:  port,
 		etcdClient:  etcdClient,
 	}, nil