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Name

tcppipe - create TCP connection to send data from/to pipe

Synopsis

tcppipe [parameter=value]

Description

TCPpipe is a very small program to transfer any kind of data from one host to another over a network without the need for ftp, scp, http etc. To do this, first TCPpipe on one host must listen, then TCPpipe on the other host can connect. After this the data can be transfered: The sending TCPpipe reads from standard-input and sends it to the receiving TCPpipe, which writes to standard-output. This allows to connect two processes on different machines.

Several other implementation of the same idea exist, with the same name.

Parameters

The following parameters are recognized in any order if the keyword is also given:
host=name
hostname, only needed in receive mode [Default: none, i.e. program is started in send mode].
port=tcp_port
TCP/IP port to communicate with [Default: 2801]
bufsize=byte_size
buffersize to use for transfer. Applies to both the sender and receiver, and best performance should be expected when they are the same. [Default: 1024]

Examples

On machine A you start by piping data into tcppipe, note no hostname is needed, but we use the default port (2801) and buffersize (1024): 
    A% mkplummer - 1000 | tcppipe
After this has been launched, on machine B you can now tell it to expect data from machine A and pass the data on to the task in the pipe: 
    B% tcppipe A | tsf -

Here are some cut and pasteable lines in C-shell that may be useful. Notice the user of an "auto-incrementing" portnumber, since the usage of the bind/listen/accept causes TCP/IP to lock that port for a few minutes: 

   dd if=/dev/zero of=zero1 bs=1024 count=1024
   dd if=/dev/zero of=zero10 bs=1024 count=10240
   dd if=/dev/zero of=zero100 bs=1024 count=102400
   set port=3000
   set host=192.168.1.6
   set buf=10240
   cat zero1 | tcppipe port=$port bufsize=$buf ; @ port++
   tcppipe $host report=t port=$port bufsize=$buf; @ port++
   @ port--

Future

One possible future enhancement in NEMO would be to integrate this with existing enhancements to stropen(3NEMO) , the previous example would now read 
    A% mkplummer + 1000
    B% tsf +A
with a full filename syntax of +host:port/bufsize. Any of the three components can be left off, but the separators must be kept not to confuse the parser.

Caveats

A TCP/IP connnection that was used, will remain blocked for usage on that same port for a little while (usually 60 seconds). Equally so, tcppipe will only listen for so long until it gives up, it will not block that port forever (check ???? - it certainly is a very long time)

See Also

redir(l) , nc(1) , libpipeline(1) socat - http://www.dest-unreach.org/socat/

libpipeline - http://libpipeline.nongnu.org/

Files

src/tools/tcppipe

Author

Grischa Weberstaedt (original), Peter Teuben (NEMO)

Update History


2001           Created     Grischa Weberstaedt
02-Jul-01    V0.3 added user interface for NEMO    PJT
10-feb-04    V0.4 added a reporting option, changed keyname    PJT

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