This small program receives UDP datagrams on a given port, and resends those datagrams to a specified set of receivers. In addition, a sampling divisor N may be specified individually for each receiver, which will then only receive one in N of the received packets.
This package is distributed under https://github.com/sleinen/samplicator/
See INSTALL.md.
See the AUTHORS file.
The usage convention for the program is
$ samplicate [<option>...] [<destination>...]
Where each <option> can be one of
-d <level> to set the debugging level
-s <address> to set interface address on which to listen
for incoming packets (default any)
-p <port> to set the UDP port on which to listen for
incoming packets (default 2000)
-b <buflen> size of receive buffer (default 65536)
-c <configfile> specify a config file to read
-x <delay> to specify a transmission delay after each packet,
in units of microseconds
-S maintain (spoof) source addresses
-n don't compute UDP checksum (only relevant with -S)
-f fork program into background
-m <pidfile> write the process ID to a file
-4 IPv4 only
-6 IPv6 only
-h to print a usage message and exit
-u <pdulen> size of max pdu on listened socket (default 65536)
-X use command line receivers for unmatched sources\n\
and each <destination> should be specified as
<addr>[/<port>[/<interval>[,ttl]]], where
<addr> IP address of the receiver
<port> port UDP number of the receiver (default 2000)
<freq> number of received datagrams between successive
copied datagrams for this receiver.
<ttl> The TTL (IPv4) or hop-limit (IPv6) for
outgoing datagrams.
Config file format:
source: [receiver ...]
a.b.c.d[/e.f.g.h]: receiver ...
a.b.c.d[/e.f.g.h]:
*: receiver ...
where:
a.b.c.d is the senders IP address
e.f.g.h is a mask to apply to the sender (default 255.255.255.255)
* denotes receivers for unmatched sources
receiver see above
The source address of incoming packets is matched against three categories in order: 1) blacklist, 2) standard, 3) unmatched. Source addresses will only be processed by the first category where a match is found.
Receivers from all matching sources defined in the configuration will get copies as sources may overlap with masks. Sources defined without a receiver are the exception. They are explicitly blacklisted and dropped before any further matches are processed.
The wildcard source is used to denote the unmatched category. A source address that does not match any known sources from the configuration are processed here. Unmatched sources are dropped unless the wildcard source is explicitly defined.
Any receivers defined on the command line will get all packets as they match as 0.0.0.0/0. The -X option changes this behavior and places all command line receivers in the unmatched category.