NFQ is the new and improved way to process iptables packets:
./snort --daq nfq \ [--daq-var device=<dev>] \ [--daq-var proto=<proto>] \ [--daq-var queue=<qid>] \ [--daq-var queue_len=<qlen>] <dev> ::= ip | eth0, etc; default is IP injection <proto> ::= ip4 | ip6 | ip*; default is ip4 <qid> ::= 0..65535; default is 0 <qlen> ::= 0..65535; default is 0
Notes on iptables can be found in the DAQ distro README.