.IR addr ]
.RB [ \-p
.IR port ]
+.RB [ \-n
+.IR tunnel ]
.br
.RB [ \-U
.B "\-u, \-\-usage"
Writes a brief usage summary to standard output and exits with status 0.
.TP
-.B "\-\-tunnel"
-Writes a string to standard output describing the configured tunnelling
-method and exits with status 0. This is intended for the use of the
+.B "\-\-tunnels"
+Writes to standard output a list of the configured tunnel drivers, one
+per line, and exits with status 0. This is intended for the use of the
start-up script, so that it can check that it will actually work.
.TP
.B "\-D, \-\-daemon"
Use the specified UDP port for all communications with peers, rather
than an arbitarary kernel-assigned port.
.TP
+.BI "\-n, \-\-tunnel=" tunnel
+Use the specified tunnel driver for new peers by default.
+.TP
.BI "\-U, \-\-setuid=" user
Set uid to that of
.I user
has the addresses 10.0.1.1 and 200.0.1.1; site B's gateway is
.B bob
and has addresses 10.0.2.1 and 200.0.2.1.
-.PP
-This isn't quite complicated enough. Each of
-.B alice
-and
-.B bob
-needs an extra IP address which we'll use when setting up the
-point-to-point link. These addresses need to be routable, at least
-within the virtual private network: unfortunately, you can't just use
-the same pair everywhere. We'll assign
-.B alice
-the point-to-point address 192.168.0.1, and
-.B bob
-the address 192.168.0.2.
.hP 1.
Install
.B tripe
servers up. Run
.RS
.VS
-tripectl \-slD \-S\-P23169
+tripectl \-slD \-S\-p22003
.VE
on each of
.B alice
and
.BR bob .
(The
-.RB ` \-P23169 '
-forces the server to use UDP port 23169: use some other number if 23169
-is inappropriate for your requirements. I chose it by reducing the
-RIPEMD160 hash of
-.RB ` tripe\-port\-number\e0 '
-modulo 2\*(ss16\*(se.)
+.RB ` \-p22003 '
+forces the server to use UDP port 22003: use some other number if 22003
+is inappropriate for your requirements. I chose it by taking the first
+16 bits of the RIPEMD160 hash of
+.RB ` TrIPE '.
.RE
.hP 6.
To get
.VS
#! /bin/sh
-tripectl add bob 200.0.2.1 23169
+tripectl add bob 200.0.2.1 22003
ifname=`tripectl ifname bob`
-ifconfig $ifname \e
- 192.168.0.1 \e
- pointopoint 192.168.0.2
+ifconfig $ifname 10.0.1.1 pointopoint 10.0.2.1
route add -net \e
10.0.2.0 netmask 255.255.255.0 \e
- gw 192.168.0.2
+ gw 10.0.2.1
.VE
Read
.BR ifconfig (8)
.B tripe
to read and write network packets to a pair of file descriptors using
SLIP encapsulation. No fancy header compression of any kind is
-supported. The intended use is that you allocate a pty pair, set the
-slave's line discipline to SLIP, and hand the
+supported.
+.PP
+Two usage modes are supported: a preallocation system, whereby SLIP
+interfaces are created and passed to the
+.B tripe
+server at startup; and a dynamic system, where the server runs a script
+to allocate a new SLIP interface when it needs one. It is possible to
+use a mixture of these two modes, starting
.B tripe
-server the master end, though in fact any old file descriptors will do.
+with a few preallocated interfaces and having it allocate more
+dynamically as it needs them.
+.PP
+The behaviour of
+.BR tripe 's
+SLIP driver is controlled by the
+.B TRIPE_SLIPIF
+environment variable. The server will not create SLIP tunnels if this
+variable is not defined. The variable's value is a colon-delimited list
+of preallocated interfaces, followed optionally by the filename of a
+script to run to dynamically allocate more interfaces.
.PP
-The SLIP descriptors must be set up and running before the daemon is
-started, and you must inform it about the SLIP descriptors it's meant to
-use in an environment variable
-.BR TRIPE_SLIPIF ,
-whose value must be a colon-separated list of items of the form
+A static allocation entry has the form
.IR infd [ \c
.BI , outfd \c
.RB ] \c
.BI = \c
-.IR ifname .
+.IR ifname ,
If the
.I outfd
is omitted, the same file descriptor is used for input and output.
.PP
+The dynamic allocation script must be named by an absolute or relative
+pathname, beginning with
+.RB ` / '
+or
+.RB ` . '.
+The server will pass the script an argument, which is the name of the
+peer for which the interface is being created. The script should
+allocate a new SLIP interface (presumably by creating a pty pair),
+configure it appropriately, and write the interface's name to its
+standard output, followed by a newline. It should then read and write
+SLIP packets on its stdin and stdout. The script's stdin will be closed
+when the interface is no longer needed, and the server will attempt to
+send it a
+.B SIGTERM
+signal (though this may fail if the script runs with higher privileges
+than the server).
+.PP
The output file descriptor should not block unless it really needs to:
the
.B tripe
-daemon assumes that it won't, and will get wait for it to accept output.
+daemon assumes that it won't, and will get wedged waiting for it to
+accept output.
.SS "About the name"
The program's name is
.BR tripe ,
~mdw / tripe / blobdiff