NAME

sc_remoted —

interact with a collection of remotely controlled scamper instances

SYNOPSIS

sc_remoted [-?46D] [-O options] [-P [ip:]port] [-U directory] [-c tls-certificate] [-p tls-privatekey] [-e pidfile] [-Z zombie-time]

DESCRIPTION

The sc_remoted utility provides the ability to connect to a scamper(1) instance running remotely and interact with it by issuing commands and receiving results in warts format. The options are as follows:

-?

prints a list of command line options and a synopsis of each.

-D

causes sc_remoted to operate as a daemon.

-4

causes sc_remoted to only listen for IPv4-based connections.

-6

causes sc_remoted to only listen for IPv6-based connections.

-O options

allows the behavior of sc_remoted to be further tailored. The current choices for this option are:

allowgroup: allow members of the unix domain socket's group to access to the unix domain sockets created by sc_remoted
allowother: allow anyone on the system access to the unix domain sockets created by sc_remoted
debug: print debugging messages
select: use select(2) with all sockets, rather than epoll(2) or kqueue(2)

-P [ip:]port

specifies the IP address and port on the local host where sc_remoted should listen for incoming connections. If an IP address is not specified, sc_remoted will listen on all available IP addresses for incoming connections.

-U directory

specifies the directory on the local host where unix domain sockets corresponding to remote hosts should be placed.

-c tls-certificate

specifies the server certificate file in PEM format to advertise to remote scamper(1) instances.

-p tls-privatekey

specifies the private key file in PEM format that corresponds to the certificate file. This key should have a passphrase. sc_remoted will prompt for the passphrase when starting up.

-e pidfile

specifies the name of a file to write the process ID to.

-Z zombie-time

specifies the length of time sc_remoted will retain state for a disconnected scamper(1) instance, allowing it to resume. By default sc_remoted retains state for 15 minutes.

EXAMPLES

The intended use of the remote control socket built into scamper(1) is as follows. A central server with IP addresses 192.0.2.1 and 2001:db8::1 runs a sc_remoted process listening on a port for remote scamper process, placing control sockets in a specified directory:

sc_remoted -P 31337 -U
  scamper-remote-sockets

Then, a remote host with IP address 198.51.100.55 runs scamper and connects to the remote controller:

scamper -R
  192.0.2.1:31337

The sc_remoted process places a unix domain socket in the directory corresponding to the remote process. The name corresponds to the source IP address and port the remote scamper process connected to controller with. If the scamper process used source port 1025, then the unix domain socket's name will be

scamper-remote-sockets/198.51.100.55:1025

If a second remote host with IP address 2001:db8:1234::1 runs scamper and connects to the remote controller:

scamper -R
  [2001:db8::1]:31337

The same sc_remoted process will place another unix domain socket in the directory corresponding to the remote process. If the scamper process used source port 1026, then the unix domain socket's name will be

scamper-remote-sockets/2001:db8:1234::1.1026

USING TRANSPORT LAYER SECURITY

sc_remoted and scamper support the use of transport layer security (TLS) using OpenSSL to authenticate and encrypt communications between sc_remoted and scamper. To use this support requires a public certificate signed by a certificate authority. Scamper will verify the certificate presented by sc_remoted and disconnect if the certificate presented by sc_remoted cannot be validated.

Generating a certificate that will be accepted by scamper requires you to create a certificate request and pass it for signing to a certificate authority. To generate a private key in file remotepriv.pem, and a request to sign the key in remotereq.pem:

openssl req -new -keyout
  remotepriv.pem -out remotereq.pem

and then send the remotereq.pem file to the certificate authority for signing. Do not send remotepriv.pem; that key must remain private to you. When openssl prompts for a passphrase, choose a passphrase that is unique and keep the passphrase secret. When your chosen certificate authority signs your private key, it will return a file which we will call remotecert.pem. Both remotecert.pem and remotepriv.pem are required parameters to sc_remoted to enable TLS support:

sc_remoted -P 31337 -U
  scamper-remote-sockets -c remotecert.pem -p remotepriv.pem

and then passing the -O tls option to scamper:

scamper -R example.com:31337 -O
  tls

SIGNAL HANDLERS

sc_remoted installs handlers for two signals: SIGINT and SIGHUP. SIGINT causes sc_remoted to exit gracefully. SIGHUP causes sc_remoted to reload the TLS certificate and private key, without interrupting existing TLS connections.

AUTHORS

sc_remoted was written by Matthew Luckie <mjl@luckie.org.nz>.