默认的daq是pcap，当然还有其它的实现方式；为了兼容各种sniffer，提供统一的接口，就有了libdaq这个库：
通过阅读代码，抽象出来一个软件框架图：
另类API：一类是供其上的binary使用，不需要关心使用哪一类sniffer，二是中间件API，每类plugin都需要实现其中重要的函数；
当前已经实现的模块包括：
./modules/
├── afpacket
├── bpf
├── divert
├── dump
├── fst
├── netmap
├── nfq
├── pcap
└── trace
?Pcap: default DAQ
?AFPACKET:
similar
to the memory mapped pcap DAQ but no external library is
required
?NFQ:
built
on top of the Linux netfilter packet filtering framework; the module operates on packets queued by
the kernel packet filter for userspace consumption via the NFQUEUE mechanism, usually controlled by iptables
rules.
?Dump:
A
wrapper DAQ module that presents the configuration stack as inline-interface-
and injection-capable.
?Netmap:
built
on top of the netmap project; The netmap project is a framework for very high speed packet I/O.
?FST:
The
Flow State Table (FST) DAQ module is a wrapper module that mimics operating on
top of a flow-tracking dataplane.