.Dd July  6, 2020
.Dt POUNCE 1
.Os
.
.Sh NAME
.Nm pounce
.Nd IRC bouncer
.
.Sh SYNOPSIS
.Nm
.Op Fl NTev
.Op Fl A Ar cert
.Op Fl C Ar cert
.Op Fl H Ar host
.Op Fl K Ar priv
.Op Fl P Ar port
.Op Fl Q Ar time
.Op Fl R Ar caps
.Op Fl S Ar bind
.Op Fl U Ar unix
.Op Fl W Ar pass
.Op Fl a Ar auth
.Op Fl c Ar cert
.Op Fl f Ar save
.Op Fl h Ar host
.Op Fl j Ar join
.Op Fl k Ar priv
.Op Fl n Ar nick
.Op Fl p Ar port
.Op Fl q Ar quit
.Op Fl r Ar real
.Op Fl s Ar size
.Op Fl u Ar user
.Op Fl w Ar pass
.Op Fl y Ar away
.Op Ar config ...
.
.Nm
.Op Fl A Ar ca
.Fl g Ar cert
.
.Nm
.Fl x
.
.Sh DESCRIPTION
The
.Nm
daemon
is a multi-client, TLS-only IRC bouncer.
It maintains a persistent connection to an IRC server
while allowing clients to connect and disconnect,
receiving messages that were missed upon reconnection.
The IRCv3.2
.Sy server-time
extension is used to indicate
when messages were originally received.
.
.Pp
One instance of
.Nm
must be configured for each IRC network.
Instances of
.Nm
must either use different local ports with
.Fl P
or different local hosts with
.Fl H
and
.Fl U
to be dispatched from the same port by
.Xr calico 1 .
.
.Pp
TLS certificates can be automatically loaded from
.Pa /usr/local/etc/letsencrypt
(or equivalent)
based on the local host set by
.Fl H .
These certificates can be obtained using
.Xr certbot 8 .
.
.Pp
Clients must uniquely identify themselves to
.Nm
by their IRC username.
See
.Sx Client Configuration
for details.
.
.Pp
Options can be loaded from
files listed on the command line.
Each option is placed on a line,
and lines beginning with
.Ql #
are ignored.
The options are listed below
following their corresponding flags.
.
.Pp
The arguments are as follows:
.
.Bl -tag -width Ds
.It Fl A Ar path , Cm local-ca = Ar path
Require clients to authenticate
using a TLS client certificate
signed by the certificate authority loaded from
.Ar path .
See
.Sx Generating Client Certificates .
If
.Fl W
is also set,
clients may instead authenticate
with a server password.
.
.It Fl C Ar path , Cm local-cert = Ar path
Load TLS certificate from
.Ar path .
The default path is the
.Xr certbot 8
path for the
.Ar host
set by
.Fl H .
.
.It Fl H Ar host , Cm local-host = Ar host
Bind to
.Ar host .
The default host is localhost.
.
.It Fl K Ar path , Cm local-priv = Ar path
Load TLS private key from
.Ar path .
The default path is the
.Xr certbot 8
path for the
.Ar host
set by
.Fl H .
.
.It Fl N , Cm no-names
Do not request
.Ql NAMES
for each channel when a client connects.
This avoids already connected clients
receiving unsolicited responses
but prevents new clients from populating user lists.
.
.It Fl P Ar port , Cm local-port = Ar port
Bind to
.Ar port .
The default port is 6697.
.
.It Fl Q Ar ms , Cm queue-interval = Ar ms
Set the server send queue interval in milliseconds.
The queue is only used
for automated messages sent by
.Nm .
Messages from clients
are sent to the server immediately.
The default interval is 200 milliseconds.
.
.It Fl R Ar caps , Cm blind-req = Ar caps
Blindly request the IRCv3 capabilities
.Ar caps .
This can be used to enable hidden capabilities,
such as
.Sy userhost-in-names
on freenode.
.
.It Fl S Ar host , Cm bind = Ar host
Bind to source address
.Ar host
when connecting to the server.
.
.It Fl T
Do not advertise a
strict transport security (STS) policy
to clients.
.
.It Fl U Ar path , Cm local-path = Ar path
Bind to a UNIX-domain socket at
.Ar path .
Clients are only accepted as dispatched by
.Xr calico 1 .
If
.Ar path
is a directory,
the
.Ar host
set by
.Fl H
is appended to it.
This option takes precedence over
.Fl H
and
.Fl P .
.
.It Fl W Ar pass , Cm local-pass = Ar pass
Require the server password
.Ar pass
for clients to connect.
The
.Ar pass
string must be hashed using
.Fl x .
If
.Fl A
is also set,
clients may instead authenticate
using a TLS client certificate.
.
.It Fl a Ar user : Ns Ar pass , Cm sasl-plain = Ar user : Ns Ar pass
Authenticate as
.Ar user
with
.Ar pass
using SASL PLAIN.
Since this method requires
the account password in plaintext,
it is recommended to use SASL EXTERNAL instead with
.Fl e .
.
.It Fl c Ar path , Cm client-cert = Ar path
Load the TLS client certificate from
.Ar path .
If the private key is in a separate file,
it is loaded with
.Fl k .
With
.Fl e ,
authenticate using SASL EXTERNAL.
Certificates can be generated with
.Fl g .
.
.It Fl e , Cm sasl-external
Authenticate using SASL EXTERNAL,
also known as CertFP.
The TLS client certificate is loaded with
.Fl c .
See
.Sx Configuring CertFP .
.
.It Fl f Ar path , Cm save = Ar path
Load the contents of the buffer from
.Ar path ,
if it exists,
and truncate it.
On shutdown,
save the contents of the buffer to
.Ar path .
.
.It Fl g Ar path
Generate a TLS client certificate using
.Xr openssl 1
and write it to
.Ar path .
The certificate is signed
by the certificate authority if
.Fl A
is set,
otherwise it is self-signed.
.
.It Fl h Ar host , Cm host = Ar host
Connect to
.Ar host .
.
.It Fl j Ar chan , Cm join = Ar chan
Join the comma-separated list of
.Ar chan .
.
.It Fl k Ar path , Cm client-priv = Ar path
Load the TLS client private key from
.Ar path .
.
.It Fl n Ar nick , Cm nick = Ar nick
Set nickname to
.Ar nick .
The default nickname is the user's name.
.
.It Fl p Ar port , Cm port = Ar port
Connect to
.Ar port .
The default port is 6697.
.
.It Fl q Ar mesg , Cm quit = Ar mesg
Quit with message
.Ar mesg
when shutting down.
.
.It Fl r Ar real , Cm real = Ar real
Set realname to
.Ar real .
The default realname is the same as the nickname.
.
.It Fl s Ar size , Cm size = Ar size
Set the number of messages contained in the buffer to
.Ar size .
The size must be a power of two.
The default size is 4096.
.
.It Fl u Ar user , Cm user = Ar user
Set username to
.Ar user .
The default username is the same as the nickname.
.
.It Fl v , Cm verbose
Write IRC messages to standard error
in the following colors:
.Pp
.Bl -tag -width Ds -compact
.It red
from
.Nm
to the server
.It green
from the server to
.Nm
.It yellow
from clients to
.Nm
.It blue
from
.Nm
to clients
.El
.
.It Fl w Ar pass , Cm pass = Ar pass
Log in with the server password
.Ar pass .
.
.It Fl x
Prompt for a password
and output a hash
for use with
.Fl W .
.
.It Fl y Ar mesg , Cm away = Ar mesg
Set away status to
.Ar mesg
when no clients are connected.
.El
.
.Pp
Client connections are not accepted
until successful login to the server.
If the server connection is lost,
the
.Nm
daemon exits.
.
.Pp
Upon receiving the
.Dv SIGUSR1
signal,
the certificate and private key
will be reloaded from the paths
specified by
.Fl C
and
.Fl K .
.
.Ss Client Configuration
Clients should be configured to
connect to the host and port set by
.Fl H
and
.Fl P ,
with TLS or SSL enabled.
If
.Fl W
is used,
clients must send a server password.
If
.Fl A
is used,
clients must connect with a client certificate
and may request SASL EXTERNAL.
If both are used,
clients may authenticate with either method.
.
.Pp
Clients must register with unique usernames,
for example the name of the client software
or location from which it is connecting.
New clients with the same username
are assumed to be reconnections
and will cause previous connections
to stop receiving messages.
The nickname and real name
sent by clients are ignored.
.
.Pp
Clients which request the
.Sy causal.agency/passive
capability
or with usernames beginning with hyphen
.Ql -
are considered passive
and do not affect automatic away status.
.
.Pp
Pass-through of the following IRCv3 capabilities
is supported:
.Sy account-notify ,
.Sy account-tag ,
.Sy away-notify ,
.Sy batch ,
.Sy cap-notify ,
.Sy chghost ,
.Sy extended-join ,
.Sy invite-notify ,
.Sy labeled-response ,
.Sy message-tags ,
.Sy multi-prefix ,
.Sy server-time ,
.Sy setname ,
.Sy userhost-in-names .
.
.Pp
Private messages and notices
sent to the user's own nickname
are relayed only to other clients,
not to the server.
.
.Ss Generating Client Certificates
.Bl -enum
.It
Generate a self-signed certificate authority (CA):
.Bd -literal -offset indent
pounce -g auth.pem
.Ed
.It
Generate and sign client certificates
using the CA:
.Bd -literal -offset indent
pounce -A auth.pem -g client1.pem
pounce -A auth.pem -g client2.pem
.Ed
.It
Since only the public key is needed
for certificate verification,
extract it from the CA:
.Bd -literal -offset indent
openssl x509 -in auth.pem -out auth.crt
.Ed
.It
Configure
.Nm
to verify client certificates
against the CA:
.Bd -literal -offset indent
local-ca = auth.crt
# or: pounce -A auth.crt
.Ed
.El
.
.Ss Configuring CertFP
.Bl -enum
.It
Generate a new TLS client certificate:
.Bd -literal -offset indent
pounce -g example.pem
.Ed
.It
Connect to the server using the certificate:
.Bd -literal -offset indent
client-cert = example.pem
# or: pounce -c example.pem
.Ed
.It
Identify with services or use
.Cm sasl-plain ,
then add the certificate fingerprint to your account:
.Bd -literal -offset indent
/msg NickServ CERT ADD
.Ed
.It
Enable SASL EXTERNAL
to require successful authentication when connecting:
.Bd -literal -offset indent
client-cert = example.pem
sasl-external
# or: pounce -e -c example.pem
.Ed
.El
.
.Ss Service Configuration
Add the following to
.Pa /etc/rc.conf
to enable the
.Nm
daemon:
.Bd -literal -offset indent
pounce_enable="YES"
.Ed
.
.Pp
By default,
the
.Nm
daemon is started in the
.Pa /usr/local/etc/pounce
directory.
Configuration files in that location
can be loaded by setting
.Va pounce_flags :
.Bd -literal -offset indent
pounce_flags="example.conf"
.Ed
.
.Pp
The
.Nm
service supports profiles
for running multiple instances.
Set
.Va pounce_profiles
to a space-separated list of names.
Flags for each profile will be set from
.Va pounce_${profile}_flags .
For example:
.Bd -literal -offset indent
pounce_profiles="example1 example2"
pounce_example1_flags="example1.conf"
pounce_example2_flags="example2.conf"
.Ed
.
.Pp
The commands
.Cm start , stop ,
etc.\&
will operate on the profile given as an additional argument,
or on all profiles without an additional argument.
.
.Pp
The
.Cm reload
command will cause the
.Nm
daemon to reload certificate files.
To reload other configuration,
use the
.Cm restart
command.
.
.Sh ENVIRONMENT
.Bl -tag -width Ds
.It Ev USER
The default nickname.
.El
.
.Sh EXAMPLES
Obtain a certificate and start
.Nm :
.Bd -literal -offset indent
certbot certonly -d pounce.example.org
pounce -H pounce.example.org -h chat.freenode.net -j '#ascii.town'
.Ed
.
.Pp
Equivalent configuration file:
.Bd -literal -offset indent
local-host = pounce.example.org
host = chat.freenode.net
join = #ascii.town
.Ed
.
.Sh SEE ALSO
.Xr calico 1
.
.Sh STANDARDS
.Bl -item
.It
.Rs
.%R RFC 2812
.%A C. Kalt
.%T Internet Relay Chat: Client Protocol
.%I IETF
.%D April 2000
.%U https://tools.ietf.org/html/rfc2812
.Re
.
.It
.Rs
.%R RFC 4616
.%A K. Zeilenga, Ed.
.%T The PLAIN Simple Authentication and Security Layer (SASL) Mechanism
.%I IETF
.%D August 2006
.%U https://tools.ietf.org/html/rfc4616
.Re
.
.It
.Rs
.%A S. Josefsson
.%T The Base16, Base32, and Base64 Data Encodings
.%I IETF
.%R RFC 4648
.%D October 2006
.%U https://tools.ietf.org/html/rfc4648
.Re
.
.It
.Rs
.%A Attila Molnar
.%A James Wheare
.%T IRCv3 Strict Transport Security
.%I IRCv3 Working Group
.%U https://ircv3.net/specs/extensions/sts
.Re
.
.It
.Rs
.%A Attila Molnar
.%A William Pitcock
.%T IRCv3.2 SASL Authentication
.%I IRCv3 Working Group
.%U https://ircv3.net/specs/extensions/sasl-3.2
.Re
.
.It
.Rs
.%A Kevin L. Mitchell
.%A Perry Lorier
.%A Lee Hardy
.%A William Pitcock
.%A Attila Molnar
.%A Daniel Oakley
.%A James Wheare
.%T IRCv3 Client Capability Negotiation
.%I IRCv3 Working Group
.%U https://ircv3.net/specs/core/capability-negotiation
.Re
.
.It
.Rs
.%A St\('ephan Kochen
.%A Alexey Sokolov
.%A Kyle Fuller
.%A James Wheare
.%T IRCv3.2 server-time Extension
.%I IRCv3 Working Group
.%U https://ircv3.net/specs/extensions/server-time-3.2
.Re
.El
.
.Ss Extensions
The
.Sy causal.agency/consumer
vendor-specific IRCv3 capability
enables the
.Sy causal.agency/pos
message tag.
The value of this tag
is a 64-bit unsigned integer
indicating the consumer position of the client
after receiving each message,
e.g.\&
.Ql @causal.agency/pos=42069 .
This capability may be requested
with the value of the last
.Sy causal.agency/pos
tag received by the client,
e.g.\&
.Ql CAP REQ causal.agency/consumer=42069 ,
setting its consumer position.
By persisting this value across connections,
a client can ensure no messages are missed,
even in case of network issues or application crashes.
.
.Pp
.%T IRCv3 Client Capability Negotiation
specifies that capabilities MAY have values in
.Ql CAP LS
or
.Ql CAP NEW
responses.
It does not, however,
indicate if
.Ql CAP REQ
capabilities MUST NOT have values.
The
.Nm
daemon parses
.Ql CAP REQ
values in the same way as
.Ql CAP LS
values.
.
.Pp
The
.Sy causal.agency/passive
vendor-specific IRCv3 capability
indicates that a client
should not affect the automatic away status.
.
.Sh AUTHORS
.An June Bug Aq Mt june@causal.agency
.
.Sh CAVEATS
One instance of
.Nm
is required for each server connection.
The
.Nm
daemon must be restarted
if the server connection is lost.
.
.Pp
The
.Nm
daemon makes no distinction between channels.
Elevated activity in one channel
may push messages from a quieter channel
out of the buffer.
.
.Sh BUGS
Send mail to
.Aq Mt list+pounce@causal.agency
or join
.Li #ascii.town
on
.Li chat.freenode.net .
.
.Pp
A client will sometimes receive its own message,
causing it to be displayed twice.
This happens when a message is sent
while responses are not yet consumed.