fix(simpleradio): use atomic.Bool for secureCoalitionRadios

The TCP receiver goroutine writes c.secureCoalitionRadios from
updateServerSettings while the UDP receiver goroutine reads it from
the voice-packet handling path, with no synchronization — a data race
the Go race detector flags and an unlucky interleaving could let a
voice packet skip the coalition filter while the flag is flipping.

Switch the field to sync/atomic.Bool and route the write/read through
Store/Load. The tri-state log message ('enabling secure coalition
radios') still fires only on transitions, via a Load() check before
Store(true).

Refs dharmab/skyeye issue 661.

Signed-off-by: SAY-5 <say.apm35@gmail.com>

Author: SAY-5

pkg/simpleradio/client.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/dharmab/skyeye/pkg/simpleradio/types"
@@ -49,7 +50,9 @@ type Client struct {
 	clientsLock sync.RWMutex
 
 	// secureCoalitionRadios indicates if the client should only receive transmissions from the same coalition.
-	secureCoalitionRadios bool
+	// Written by the TCP receiver goroutine (updateServerSettings) and read by the UDP receiver
+	// goroutine (receive path); use atomic.Bool to avoid a data race.
+	secureCoalitionRadios atomic.Bool
 
 	// rxChan is a channel where received transmission are published. A read-only version is available publicly.
 	rxChan chan Transmission

pkg/simpleradio/message.go

@@ -78,13 +78,13 @@ func (c *Client) updateServerSettings(message types.Message) {
 	log.Debug().Any("serverSettings", message.ServerSettings).Msg("received server settings")
 	if enabled, ok := message.ServerSettings[string(types.CoalitionAudioSecurity)]; ok {
 		if strings.ToLower(enabled) == "true" {
-			if !c.secureCoalitionRadios {
+			if !c.secureCoalitionRadios.Load() {
 				log.Info().Msg("enabling secure coalition radios")
 			}
-			c.secureCoalitionRadios = true
+			c.secureCoalitionRadios.Store(true)
 		} else {
 			log.Info().Msg("disabling secure coalition radios")
-			c.secureCoalitionRadios = false
+			c.secureCoalitionRadios.Store(false)
 		}
 	}
 	if enabled, ok := message.ServerSettings[string(types.ExternalAWACSMode)]; ok {

pkg/simpleradio/receive.go

@@ -104,7 +104,7 @@ func (c *Client) receiveVoice(ctx context.Context, in <-chan []byte, out chan<-
 
 			logger := log.With().Str("GUID", string(packet.OriginGUID)).Logger()
 
-			if c.secureCoalitionRadios {
+			if c.secureCoalitionRadios.Load() {
 				client, ok := c.clients[types.GUID(packet.OriginGUID)]
 				if !ok {
 					logger.Warn().Msg("ignoring voice packet from unknown client")