The following functions are meant for use with TCP traffic only.
void nids_killtcp (struct tcp_stream *ts);
nids_killtcp () terminates a TCP connection that ts references with RST packets to both the client and the server. This is the only location inside libnids that libnet's functionality is used.
void nids_discard (struct tcp_stream *ts, int num);
You can call nids_discard () from inside the user-defined TCP callback function to discard (mark as read) the num number of bytes from the TCP connection that ts references.