xmppipe: stdio over XMPP ======================== xmppipe redirects stdin/stdout in a shell pipeline to an XMPP MUC (XEP-0045). xmppipe supports flow control using stream management (XEP-0198) and can optionally deal with overload by acting as a circuit breaker or by discarding messages. xmppipe works with line oriented tools like grep, sed and awk by outputting each message as a newline terminated, [percent-encoded](https://en.wikipedia.org/wiki/Percent-encoding) string. xmppipe can be used in shell scripts to quickly write interactive bots for monitoring systems or for sending alerts. Usage ----- xmppipe [*options*] XMPPIPE_USERNAME=me@example.com XMPPIPE_PASSWORD="password" xmppipe -o muc Requirements ------------ * [libstrophe](https://github.com/strophe/libstrophe) * Linux: libuuid ~~~ apt-get install uuid-dev ~~~ Build ----- $ make Options ------- -u *JID* : XMPP username: takes precedence over environment variable -p *password* : XMPP password: takes precedence over environment variable -r *resource* : XMPP resource, used as the nickname in the MUC -o *output* : XMPP MUC name Default: stdout-*hostname*-*pid* -S *subject* : XMPP MUC subject -a *address:port* : Specify the IP address and port of the XMPP server -d : Discard stdin when MUC is empty -D : Discard stdin and print to local stdout -e : Ignore stdin EOF -s : Exit when MUC is empty -x : Base64 encode/decode data -b *size* : Size of read buffer -I *interval* : Request stream management status every interval messages -k *seconds* : Periodically send a keepalive -K *count* : Number of keepalive failures before exiting -P *ms* : Poll delay -v : Increase verbosity Decoding Percent-Encoded Strings -------------------------------- Using bash: ~~~ shell decode() { printf '%b' "${1//%/\\x}" } ~~~ Examples -------- ### Shell Bot An interactive XMPP bot written in the shell: ~~~ shell #!/bin/bash set -e set -u set -o pipefail trap cleanup 0 TMPDIR=$(mktemp -d) in="$TMPDIR/stdin" out="$TMPDIR/stdout" mkfifo $in mkfifo $out cleanup() { rm -rf $TMPDIR } decode() { printf '%b' "${1//%/\\x}" } bot() { while read line; do IFS=: set -- $line if [ "$1" = "p" ]; then decode "$line" 1>&2 echo 1>&2 elif [ "$1" = "m" ]; then USER="$(decode ${3#*%2F})" IFS=$OFS MSG="$(decode ${!#})" case $MSG in *"has set the subject to:"*) ;; "sudo make me a sandwich") echo "$USER: you're a sandwich" ;; sudo*) echo "I'm sorry, $USER. I'm afraid I can't do that." ;; uptime) uptime ;; exit) echo "exiting ..." exit 0 ;; *) echo "$@" ;; esac fi done < $out } bot > $in & xmppipe "$@" <$in >$out ~~~ ### SSH over XMPP See [examples/ssh-over-xmpp](https://github.com/msantos/xmppipe/blob/master/examples/ssh-over-xmpp): ~~~ shell # Server: has access to the destination SSH server # ssh-over-xmpp server ssh-over-xmpp server sshxmpp 1.2.3.4 22 ## Client: has access to the XMPP server ssh -o ProxyCommand="ssh-over-xmpp client sshxmpp" 127.0.0.1 ~~~ ### Stream Events from Riemann This example will stream events from a query to an XMPP MUC using [Riemann's](https://github.com/riemann/riemann) SSE interface. The events are written to a named pipe to avoid buffering. ~~~ shell mkfifo riemann curl -s --get --data subscribe=true \ --data-urlencode 'query=(service ~= "^example")' \ http://example.com:80/index < /dev/null > riemann & xmppipe -o "muc" -d -vv -S "riemann events" < riemann ~~~ ### Mirror a terminal session using script(1) * user ~~~ shell #!/bin/bash MUC=console TMPDIR=$(mktemp -d) FIFO=$TMPDIR/console mkfifo $FIFO stty cols 80 rows 24 (cat $FIFO | xmppipe -r user -o $MUC -x) > /dev/null 2> $TMPDIR/stderr & script -q -f $FIFO ~~~ * viewers ~~~ shell #!/bin/bash decode() { printf '%b' "${1//%/\\x}" } stty cols 80 rows 24 xmppipe -r viewer -o console -x | while read l; do IFS=: set -- $l if [ "$1" = "m" ]; then decode $5 fi done ~~~ ### Mirror a terminal session to a web page Environment Variables --------------------- * XMPPIPE_USERNAME: XMPP jid * XMPPIPE_PASSWORD: XMPP password Format ------ Each message is terminated by a new line. Message fields are separated by ":" and percent encoded. ### Presence p::: Example: p:available:test@muc.example.com/xmppipe:occupant@example.com/1234 ### Message m:::: Example: m:groupchat:test@muc.example.com/mobile:user1@example.com/1234:Hello m:chat:user1@example.com/mobile:user2@example.com:Message%20goes%20here Compatibility ------------- Tested with ejabberd and mongooseim. Security Considerations ----------------------- [libstrophe](https://github.com/strophe/libstrophe.git) does not verify the TLS server certificates. Sessions can be MITM'ed. libstrophe has support for TLS certificate verification on a [branch](https://github.com/strophe/libstrophe/tree/tls-cert). [libmesode](https://github.com/boothj5/libmesode.git) supports TLS certificate verification. License ------- Copyright (c) 2015-2016, Michael Santos Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. TODO ---- * Support TLS certificate verification Switch to using [libmesode](https://github.com/boothj5/libmesode) * support [XEP-0384: OMEMO Encryption](https://xmpp.org/extensions/xep-0384.html) * sandbox After connecting to the XMPP server, xmppipe reads from stdin, writes to stdout and read/writes from the network socket. Drop additional capabilities using OS-specific sandboxes: * OpenBSD: pledge(2) * Linux: BPF syscall filtering using prctl(2) or seccomp(2) * FreeBSD: capabilities using capsicum(4) * any: setrlimit(2)