CUPTURE TERMINAL (cute) (c) 2014 Vitaly Zuevsky

Compiled for:
Linux ubuntu 3.8.0-29-generic #42~precise1-Ubuntu SMP Wed Aug 14 15:31:16 UTC 2013 i686 i686 i386 GNU/Linux

The tool captures UDP multicast or unicast, dumps it to file(s) seamlessly at
the application layer, and provides operational timestamps. Usage:

./cute <MCast GRP> <UDP port> <dump location> [if name]

In case of unicast, <MCast GRP> is the IP address of the receiving interface.
In case of multicast, machine's global routing table guides which receiving
interface will be used, therefore, appropriate static route must exist.
Alternatively, putting the interface explicitly as [if name] waives
necessity of taking care of global routing table. For example:

root@ubuntu:~/cute# ip addr show eth0
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:6a:b2:59 brd ff:ff:ff:ff:ff:ff
    inet 192.168.23.128/24 brd 192.168.23.255 scope global eth0
    inet6 fe80::20c:29ff:fe6a:b259/64 scope link
       valid_lft forever preferred_lft forever
root@ubuntu:~/cute#

"eth0" in this case can be used as [if name]

Initially, UDP stream is stored in a file in the current working folder from which the tool is run.
The file name is formed as "YYYYMMDDhhmmss.ts" representing the timestamp of creation, e.g.

root@ubuntu:~/cute# ls
20140413175220.ts  Makefile  cute  cute.c  cute.o
root@ubuntu:~/cute#

When the tool receives HUP signal, e.g.

root@ubuntu:~/cute# killall -HUP cute

the current .ts file is erased and the new file (with the timestamp of NOW) receives ongoing UDP stream.

When the tool receives TERM signal, e.g.

root@ubuntu:~/cute# killall -TERM cute

the current file is moved to <dump location> folder, while the new file (with the timestamp of NOW)
in the current folder takes over the storage of the UDP stream seamlessly. <dump location> can be NFS
volume or the like since the moving process is a separate thread that would not affect capture.

This functionality allows flexible slicing of continuous UDP stream.