Add a per-interface flag rfc6126-compatible.

babeld.man

@@ -411,6 +411,11 @@ for tunnel interfaces, and
 .B false
 otherwise.
 .TP
+.BR rfc6126\-compatible " {" true | false }
+Only send TLVs that are defined by RFC 6126, the older version of Babel.
+The default is
+.BR false .
+.TP
 .BI rtt\-decay " decay"
 This specifies the decay factor for the exponential moving average of
 RTT samples, in units of 1/256.  Must be between 1 and 256, inclusive.

configuration.c

@@ -608,6 +608,12 @@ parse_anonymous_ifconf(int c, gnc_t gnc, void *closure,
             if(c < -1)
                 goto error;
             if_conf->enable_timestamps = v;
+        } else if(strcmp(token, "rfc6126-compatible") == 0) {
+            int v;
+            c = getbool(c, &v, gnc, closure);
+            if(c < -1)
+                goto error;
+            if_conf->rfc6126 = v;
         } else if(strcmp(token, "rtt-decay") == 0) {
             int decay;
             c = getint(c, &decay, gnc, closure);
@@ -716,6 +722,7 @@ merge_ifconf(struct interface_conf *dest,
     MERGE(unicast);
     MERGE(channel);
     MERGE(enable_timestamps);
+    MERGE(rfc6126);
     MERGE(rtt_decay);
     MERGE(rtt_min);
     MERGE(rtt_max);

interface.c

@@ -445,6 +445,11 @@ interface_up(struct interface *ifp, int up)
                     "but timestamps are disabled on interface %s.\n",
                     ifp->name);
 
+        if(IF_CONF(ifp, rfc6126) == CONFIG_YES)
+            ifp->flags |= IF_RFC6126;
+        else
+            ifp->flags &= ~IF_RFC6126;
+
         rc = check_link_local_addresses(ifp);
         if(rc < 0) {
             goto fail;

interface.h

@@ -48,6 +48,7 @@ struct interface_conf {
     char unicast;
     int channel;
     int enable_timestamps;
+    int rfc6126;
     unsigned int rtt_decay;
     unsigned int rtt_min;
     unsigned int rtt_max;
@@ -71,6 +72,8 @@ struct interface_conf {
 #define IF_FARAWAY (1 << 4)
 /* Send most TLVs over unicast. */
 #define IF_UNICAST (1 << 5)
+/* Remain compatible with RFC 6126. */
+#define IF_RFC6126 (1 << 6)
 
 /* Only INTERFERING can appear on the wire. */
 #define IF_CHANNEL_UNKNOWN 0