fbb: FW_AUX_ONLY_EXPERIMENT

Experimental support for requesting messages on behalf of auxiliary
addresses only (not mycall).

Ref la5nta/pat#428

fbb/wl2k.go

@@ -16,6 +16,7 @@ import (
 	"net"
 	"os"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -214,6 +215,13 @@ func (s *Session) Exchange(conn net.Conn) (stats TrafficStats, err error) {
 		return stats, nil
 	}
 
+	// Experimental support for fetching messages only for auxiliary addresses (not mycall).
+	// Ref https://groups.google.com/g/pat-users/c/5G1JIEyFXe4
+	if t, _ := strconv.ParseBool(os.Getenv("FW_AUX_ONLY_EXPERIMENT")); t && len(s.localFW) > 1 {
+		s.localFW = s.localFW[1:]
+		s.log.Printf("FW_AUX_ONLY_EXPERIMENT: Requesting messages for %v", s.localFW)
+	}
+
 	// The given conn should always be closed after returning from this method.
 	// If an error occurred, echo it to the remote.
 	defer func() {

fbb/wl2k_test.go

@@ -8,6 +8,7 @@ import (
 	"bufio"
 	"fmt"
 	"net"
+	"os"
 	"strings"
 	"testing"
 )
@@ -46,6 +47,42 @@ func TestSessionP2P(t *testing.T) {
 	}
 }
 
+func TestFWAuxOnlyExperiment(t *testing.T) {
+	os.Setenv("FW_AUX_ONLY_EXPERIMENT", "1")
+	defer os.Setenv("FW_AUX_ONLY_EXPERIMENT", "0")
+
+	client, master := net.Pipe()
+
+	clientErr := make(chan error)
+	go func() {
+		s := NewSession("LA5NTA", "N0CALL", "JO39EQ", nil)
+		s.AddAuxiliaryAddress(AddressFromString("[email protected]"))
+		_, err := s.Exchange(client)
+		clientErr <- err
+	}()
+
+	masterErr := make(chan error)
+	go func() {
+		s := NewSession("N0CALL", "LA5NTA", "JO39EQ", nil)
+		s.IsMaster(true)
+		_, err := s.Exchange(master)
+		switch fw := s.RemoteForwarders(); {
+		case len(fw) != 1:
+			t.Errorf("unexpected FW count: %d", len(fw))
+		case fw[0].String() != "EMCOMM-1":
+			t.Errorf("unexpected FW address: %q", fw[0])
+		}
+		masterErr <- err
+	}()
+
+	if err := <-masterErr; err != nil {
+		t.Errorf("Master returned with error: %s", err)
+	}
+	if err := <-clientErr; err != nil {
+		t.Errorf("Client returned with error: %s", err)
+	}
+}
+
 func TestSessionCMS(t *testing.T) {
 	client, srv := net.Pipe()