network filters

[kkourt]

Tetragon already supports sock and skb types that can be used to extract information.

For example:

  kprobes:
  - call: "tcp_connect"
    syscall: false
    args:
     - index: 0
       type: "sock"

And:

  kprobes:
  - call: "dev_queue_xmit"
    syscall: false
    args:
     - index: 0
       type: "skb"

We should also add filters (e.g., source/destination port/addr/CIDR) and be able to write policies for those.

[kevsecurity]

Implemented by PR #1008.