A simple example of how to use the nmsgAPI. It reads packets from a network interface, converts them to NMSG, and
mirrors the payloads to a binary file and to stdout. Originally published in
Farsight Security's Network Message, Volume 4: The C Programming API.
To wit:
$ ./nmsgpacket
./nmsgpacket capture packets and encode as NMSG base:packet
usage: ./nmsgpacket interface count
interface: look for packets here
count: process this many payloads (positive integer)
$ ./nmsgpacket en0 5
[159] [2015-02-16 20:42:47.295350000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=154>
[159] [2015-02-16 20:42:47.296414000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=154>
[82] [2015-02-16 20:42:48.831159000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=78>
[333] [2015-02-16 20:42:48.832891000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=328>
[82] [2015-02-16 20:42:49.138423000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=78>
$ nmsgtool -r nmsgpacket.nmsg
[159] [2015-02-16 20:42:47.295350000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=154>
[159] [2015-02-16 20:42:47.296414000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=154>
[82] [2015-02-16 20:42:48.831159000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=78>
[333] [2015-02-16 20:42:48.832891000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=328>
[82] [2015-02-16 20:42:49.138423000] [1:12 base packet] [00000000] [] []
payload_type: IP
payload: <BYTE ARRAY LEN=78>