dp_packet_set_size(struct dp_packet *b, uint32_t v)
{
    /* netdev-dpdk does not currently support segmentation; consequently, for
     * all intents and purposes, 'data_len' (16 bit) and 'pkt_len' (32 bit) may
     * be used interchangably.
     *
     * On the datapath, it is expected that the size of packets
     * (and thus 'v') will always be <= UINT16_MAX; this means that there is no
     * loss of accuracy in assigning 'v' to 'data_len'.
     */
    b->mbuf.data_len = (uint16_t)v;  /* Current seg length. */
    b->mbuf.pkt_len = v;             /* Total length of all segments linked to
                                      * this segment. */
}
dp_packet_set_size(struct dp_packet *b, uint32_t v)
{
     
    b->mbuf.data_len = (uint16_t)v;   
    b->mbuf.pkt_len = v;              
}