modify_packet(struct dp_packet *pkt, char *pkt_str, size_t size,
              char *repl_str, size_t repl_size,
              uint32_t orig_used_size)
{
    replace_substring(pkt_str, size,
                      (const char *) dp_packet_tail(pkt) - pkt_str,
                      repl_str, repl_size);
    dp_packet_set_size(pkt, orig_used_size + (int) repl_size - (int) size);
}
modify_packet(struct dp_packet *pkt, char *pkt_str, size_t size,
              char *repl_str, size_t repl_size,
              uint32_t orig_used_size)
{
    replace_substring(pkt_str, size,
                      (const char *) dp_packet_tail(pkt) - pkt_str,
                      repl_str, repl_size);
    dp_packet_set_size(pkt, orig_used_size + (int) repl_size - (int) size);
}