gnrc_ipv6_ext_rh: rename GNRC_IPV6_EXT_RH_OK for clarity

sys/include/net/gnrc/ipv6/ext/rh.h

@@ -37,7 +37,7 @@ enum {
      * @brief   The routing header was successfully processed and this node
      *          is the destination (i.e. ipv6_ext_rh_t::seg_left == 0)
      */
-    GNRC_IPV6_EXT_RH_OK,
+    GNRC_IPV6_EXT_RH_AT_DST,
     /**
      * @brief   The routing header was successfully processed and the packet
      *          was forwarded to another node or should be forwarded to another
@@ -59,7 +59,7 @@ enum {
  * @param[in, out] ipv6     An IPv6 packet.
  * @param[in] ext           A routing header of @p ipv6.
  *
- * @return  @ref GNRC_IPV6_EXT_RH_OK, on success
+ * @return  @ref GNRC_IPV6_EXT_RH_AT_DST, on success
  * @return  @ref GNRC_IPV6_EXT_RH_FORWARDED, when @p pkt was forwarded
  * @return  @ref GNRC_IPV6_EXT_RH_ERROR, on error
  */

sys/include/net/gnrc/rpl/srh.h

@@ -60,7 +60,7 @@ typedef struct __attribute__((packed)) {
  * @param[in,out] ipv6  The IPv6 header of the incoming packet.
  * @param[in] rh        A RPL source routing header.
  *
- * @return  @ref GNRC_IPV6_EXT_RH_OK, on success
+ * @return  @ref GNRC_IPV6_EXT_RH_AT_DST, on success
  * @return  @ref GNRC_IPV6_EXT_RH_FORWARDED, when @p pkt *should be* forwarded
  * @return  @ref GNRC_IPV6_EXT_RH_ERROR, on error
  */

sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c

@@ -79,7 +79,7 @@ static enum gnrc_ipv6_ext_demux_status _handle_rh(gnrc_pktsnip_t *current, gnrc_
             }
             return GNRC_IPV6_EXT_FORWARDED;
 
-        case GNRC_IPV6_EXT_RH_OK:
+        case GNRC_IPV6_EXT_RH_AT_DST:
             /* this should not happen since we checked seg_left early */
             gnrc_pktbuf_release(pkt);
             return GNRC_IPV6_EXT_ERROR;

sys/net/gnrc/routing/rpl/srh/gnrc_rpl_srh.c

@@ -29,7 +29,7 @@ static char addr_str[IPV6_ADDR_MAX_STR_LEN];
 int gnrc_rpl_srh_process(ipv6_hdr_t *ipv6, gnrc_rpl_srh_t *rh)
 {
     if (rh->seg_left == 0) {
-        return GNRC_IPV6_EXT_RH_OK;
+        return GNRC_IPV6_EXT_RH_AT_DST;
     }
 
     uint8_t n = (((rh->len * 8) - GNRC_RPL_SRH_PADDING(rh->pad_resv) -