Don't send UNKNOWN or NONINTERFERING channel values.

message.c

@@ -970,8 +970,18 @@ flushupdates(struct network *net)
                         (diversity_factor * route->cost / + 128) / 256 +
                         route->add_metric;
                 }
+                if(net->channel == NET_CHANNEL_NONINTERFERING) {
+                    memcpy(channels, route->channels, DIVERSITY_HOPS);
+                } else {
+                    if(net->channel == NET_CHANNEL_UNKNOWN)
+                        channels[0] = NET_CHANNEL_INTERFERING;
+                    else {
+                        assert(net->channel > 0 && net->channel < 254);
                         channels[0] = net->channel;
+                    }
                     memcpy(channels + 1, route->channels, DIVERSITY_HOPS - 1);
+                }
+
                 channels_len = strnlen((char*)channels, DIVERSITY_HOPS);
                 really_send_update(net, route->src->id,
                                    route->src->prefix,

network.h

@@ -50,9 +50,10 @@ struct network_conf {
 #define NET_LQ (1 << 3)
 #define NET_FARAWAY (1 << 4)
 
-#define NET_CHANNEL_UNKNOWN 0
-#define NET_CHANNEL_INTERFERING 253
-#define NET_CHANNEL_NONINTERFERING 254
+/* Only INTERFERING can appear on the wire. */
+#define NET_CHANNEL_UNKNOWN -1
+#define NET_CHANNEL_INTERFERING 254
+#define NET_CHANNEL_NONINTERFERING -2
 
 struct network {
     struct network *next;
@@ -60,7 +61,7 @@ struct network {
     unsigned int ifindex;
     unsigned short flags;
     unsigned short cost;
-    unsigned char channel;
+    int channel;
     struct timeval hello_timeout;
     struct timeval update_timeout;
     struct timeval flush_timeout;