From 8d785c43bad05546cfe8e08a1bbe065a63215f9d Mon Sep 17 00:00:00 2001 From: Maxim Cournoyer Date: Tue, 9 May 2023 16:52:22 -0400 Subject: [PATCH] services: wireguard: Implement a dynamic IP monitoring feature. * gnu/services/vpn.scm () [monitor-ips?, monitor-ips-internal]: New fields. * gnu/services/vpn.scm (define-with-source): New syntax. (wireguard-service-name, strip-port/maybe) (ipv4-address?, ipv6-address?, host-name?) (endpoint-host-names): New procedure. (wireguard-monitoring-jobs): Likewise. (wireguard-service-type): Register it. * tests/services/vpn.scm: New file. * Makefile.am (SCM_TESTS): Register it. * doc/guix.texi (VPN Services): Update doc. Reviewed-by: Bruno Victal --- Makefile.am | 1 + doc/guix.texi | 17 ++++- gnu/services/vpn.scm | 150 +++++++++++++++++++++++++++++++++++++++-- tests/services/vpn.scm | 85 +++++++++++++++++++++++ 4 files changed, 247 insertions(+), 6 deletions(-) create mode 100644 tests/services/vpn.scm diff --git a/Makefile.am b/Makefile.am index d680c8c76c..d76bfd2522 100644 --- a/Makefile.am +++ b/Makefile.am @@ -558,6 +558,7 @@ SCM_TESTS = \ tests/services/lightdm.scm \ tests/services/linux.scm \ tests/services/telephony.scm \ + tests/services/vpn.scm \ tests/sets.scm \ tests/size.scm \ tests/status.scm \ diff --git a/doc/guix.texi b/doc/guix.texi index 1d8ebcd72f..33e2286455 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -32955,9 +32955,22 @@ The port on which to listen for incoming connections. @item @code{dns} (default: @code{#f}) The DNS server(s) to announce to VPN clients via DHCP. +@item @code{monitor-ips?} (default: @code{#f}) +@cindex Dynamic IP, with Wireguard +@cindex dyndns, usage with Wireguard +Whether to monitor the resolved Internet addresses (IPs) of the +endpoints of the configured peers, resetting the peer endpoints using an +IP address that no longer correspond to their freshly resolved host +name. Set this to @code{#t} if one or more endpoints use host names +provided by a dynamic DNS service to keep the sessions alive. + +@item @code{monitor-ips-internal} (default: @code{'(next-minute (range 0 60 5))}) +The time interval at which the IP monitoring job should run, provided as +an mcron time specification (@pxref{Guile Syntax,,,mcron}). + @item @code{private-key} (default: @code{"/etc/wireguard/private.key"}) -The private key file for the interface. It is automatically generated if -the file does not exist. +The private key file for the interface. It is automatically generated +if the file does not exist. @item @code{peers} (default: @code{'()}) The authorized peers on this interface. This is a list of diff --git a/gnu/services/vpn.scm b/gnu/services/vpn.scm index a884d71eb2..17aed8b3b2 100644 --- a/gnu/services/vpn.scm +++ b/gnu/services/vpn.scm @@ -11,6 +11,7 @@ ;;; Copyright © 2021 Nathan Dehnel ;;; Copyright © 2022 Cameron V Chaparro ;;; Copyright © 2022 Timo Wilken +;;; Copyright © 2023 Maxim Cournoyer ;;; ;;; This file is part of GNU Guix. ;;; @@ -31,10 +32,12 @@ (define-module (gnu services vpn) #:use-module (gnu services) #:use-module (gnu services configuration) #:use-module (gnu services dbus) + #:use-module (gnu services mcron) #:use-module (gnu services shepherd) #:use-module (gnu system shadow) #:use-module (gnu packages admin) #:use-module (gnu packages vpn) + #:use-module (guix modules) #:use-module (guix packages) #:use-module (guix records) #:use-module (guix gexp) @@ -73,6 +76,8 @@ (define-module (gnu services vpn) wireguard-configuration-addresses wireguard-configuration-port wireguard-configuration-dns + wireguard-configuration-monitor-ips? + wireguard-configuration-monitor-ips-interval wireguard-configuration-private-key wireguard-configuration-peers wireguard-configuration-pre-up @@ -741,6 +746,10 @@ (define-record-type* (default '())) (dns wireguard-configuration-dns ;list of strings (default #f)) + (monitor-ips? wireguard-configuration-monitor-ips? ;boolean + (default #f)) + (monitor-ips-interval wireguard-configuration-monitor-ips-interval + (default '(next-minute (range 0 60 5)))) ;string | list (pre-up wireguard-configuration-pre-up ;list of strings (default '())) (post-up wireguard-configuration-post-up ;list of strings @@ -871,6 +880,58 @@ (define (wireguard-activation config) (chmod #$private-key #o400) (close-pipe pipe)))))) +;;; XXX: Copied from (guix scripts pack), changing define to define*. +(define-syntax-rule (define-with-source (variable args ...) body body* ...) + "Bind VARIABLE to a procedure accepting ARGS defined as BODY, also setting +its source property." + (begin + (define* (variable args ...) + body body* ...) + (eval-when (load eval) + (set-procedure-property! variable 'source + '(define* (variable args ...) body body* ...))))) + +(define (wireguard-service-name interface) + "Return the WireGuard service name (a symbol) configured to use INTERFACE." + (symbol-append 'wireguard- (string->symbol interface))) + +(define-with-source (strip-port/maybe endpoint #:key ipv6?) + "Strip the colon and port, if present in ENDPOINT, a string." + (if ipv6? + (if (string-prefix? "[" endpoint) + (first (string-split (string-drop endpoint 1) #\])) ;ipv6 + endpoint) + (first (string-split endpoint #\:)))) ;ipv4 + +(define* (ipv4-address? address) + "Predicate to check whether ADDRESS is a valid IPv4 address." + (let ((address (strip-port/maybe address))) + (false-if-exception + (->bool (getaddrinfo address #f AI_NUMERICHOST AF_INET))))) + +(define* (ipv6-address? address) + "Predicate to check whether ADDRESS is a valid IPv6 address." + (let ((address (strip-port/maybe address #:ipv6? #t))) + (false-if-exception + (->bool (getaddrinfo address #f AI_NUMERICHOST AF_INET6))))) + +(define (host-name? name) + "Predicate to check whether NAME is a host name, i.e. not an IP address." + (not (or (ipv6-address? name) (ipv4-address? name)))) + +(define (endpoint-host-names peers) + "Return an association list of endpoint host names keyed by their peer +public key, if any." + (reverse + (fold (lambda (peer host-names) + (let ((public-key (wireguard-peer-public-key peer)) + (endpoint (wireguard-peer-endpoint peer))) + (if (and endpoint (host-name? endpoint)) + (cons (cons public-key endpoint) host-names) + host-names))) + '() + peers))) + (define (wireguard-shepherd-service config) (match-record config (wireguard interface) @@ -878,9 +939,7 @@ (define (wireguard-shepherd-service config) (config (wireguard-configuration-file config))) (list (shepherd-service (requirement '(networking)) - (provision (list - (symbol-append 'wireguard- - (string->symbol interface)))) + (provision (list (wireguard-service-name interface))) (start #~(lambda _ (invoke #$wg-quick "up" #$config))) (stop #~(lambda _ @@ -888,6 +947,87 @@ (define (wireguard-shepherd-service config) #f)) ;stopped! (documentation "Run the Wireguard VPN tunnel")))))) +(define (wireguard-monitoring-jobs config) + ;; Loosely based on WireGuard's own 'reresolve-dns.sh' shell script (see: + ;; https://raw.githubusercontent.com/WireGuard/wireguard-tools/ + ;; master/contrib/reresolve-dns/reresolve-dns.sh). + (match-record config + (interface monitor-ips? monitor-ips-interval peers) + (let ((host-names (endpoint-host-names peers))) + (if monitor-ips? + (if (null? host-names) + (begin + (warn "monitor-ips? is #t but no host name to monitor") + '()) + ;; The mcron monitor job may be a string or a list; ungexp strips + ;; one quote level, which must be added back when a list is + ;; provided. + (list + #~(job + (if (string? #$monitor-ips-interval) + #$monitor-ips-interval + '#$monitor-ips-interval) + #$(program-file + (format #f "wireguard-~a-monitoring" interface) + (with-imported-modules (source-module-closure + '((gnu services herd) + (guix build utils))) + #~(begin + (use-modules (gnu services herd) + (guix build utils) + (ice-9 popen) + (ice-9 match) + (ice-9 textual-ports) + (srfi srfi-1) + (srfi srfi-26)) + + (define (resolve-host name) + "Return the IP address resolved from NAME." + (let* ((ai (car (getaddrinfo name))) + (sa (addrinfo:addr ai))) + (inet-ntop (sockaddr:fam sa) + (sockaddr:addr sa)))) + + (define wg #$(file-append wireguard-tools "/bin/wg")) + + #$(procedure-source strip-port/maybe) + + (define service-name '#$(wireguard-service-name + interface)) + + (when (live-service-running + (current-service service-name)) + (let* ((pipe (open-pipe* OPEN_READ wg "show" + #$interface "endpoints")) + (lines (string-split (get-string-all pipe) + #\newline)) + ;; IPS is an association list mapping + ;; public keys to IP addresses. + (ips (map (match-lambda + ((public-key ip) + (cons public-key + (strip-port/maybe ip)))) + (map (cut string-split <> #\tab) + (remove string-null? + lines))))) + (close-pipe pipe) + (for-each + (match-lambda + ((key . host-name) + (let ((resolved-ip (resolve-host + (strip-port/maybe + host-name))) + (current-ip (assoc-ref ips key))) + (unless (string=? resolved-ip current-ip) + (format #t "resetting `~a' peer \ +endpoint to `~a' due to stale IP (`~a' instead of `~a')~%" + key host-name + current-ip resolved-ip) + (invoke wg "set" #$interface "peer" key + "endpoint" host-name))))) + '#$host-names))))))))) + '())))) ;monitor-ips? is #f + (define wireguard-service-type (service-type (name 'wireguard) @@ -898,6 +1038,8 @@ (define wireguard-service-type wireguard-activation) (service-extension profile-service-type (compose list - wireguard-configuration-wireguard)))) + wireguard-configuration-wireguard)) + (service-extension mcron-service-type + wireguard-monitoring-jobs))) (description "Set up Wireguard @acronym{VPN, Virtual Private Network} tunnels."))) diff --git a/tests/services/vpn.scm b/tests/services/vpn.scm new file mode 100644 index 0000000000..1607d1bbfc --- /dev/null +++ b/tests/services/vpn.scm @@ -0,0 +1,85 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2023 Maxim Cournoyer +;;; +;;; This file is part of GNU Guix. +;;; +;;; GNU Guix is free software; you can redistribute it and/or modify it +;;; under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3 of the License, or (at +;;; your option) any later version. +;;; +;;; GNU Guix is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Guix. If not, see . + +(define-module (tests services vpn) + #:use-module (gnu packages vpn) + #:use-module (gnu services vpn) + #:use-module (guix gexp) + #:use-module (ice-9 match) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-64)) + +;;; Commentary: +;;; +;;; Unit tests for the (gnu services vpn) module. +;;; +;;; Code: + +;;; Access some internals for whitebox testing. +(define ipv4-address? (@@ (gnu services vpn) ipv4-address?)) +(define ipv6-address? (@@ (gnu services vpn) ipv6-address?)) +(define host-name? (@@ (gnu services vpn) host-name?)) +(define endpoint-host-names + (@@ (gnu services vpn) endpoint-host-names)) + +(test-begin "vpn-services") + +(test-assert "ipv4-address?" + (every ipv4-address? + (list "192.95.5.67:1234" + "10.0.0.1"))) + +(test-assert "ipv6-address?" + (every ipv6-address? + (list "[2001:db8::c05f:543]:2468" + "2001:db8::c05f:543" + "2001:db8:855b:0000:0000:0567:5673:23b5" + "2001:db8:855b::0567:5673:23b5"))) + +(define %wireguard-peers + (list (wireguard-peer + (name "dummy1") + (public-key "VlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XjoalC8=") + (endpoint "some.dynamic-dns.service:53281") + (allowed-ips '())) + (wireguard-peer + (name "dummy2") + (public-key "AlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XgoalC9=") + (endpoint "example.org") + (allowed-ips '())) + (wireguard-peer + (name "dummy3") + (public-key "BlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XgoalC7=") + (endpoint "10.0.0.7:7777") + (allowed-ips '())) + (wireguard-peer + (name "dummy4") + (public-key "ClesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XgoalC6=") + (endpoint "[2345:0425:2CA1::0567:5673:23b5]:44444") + (allowed-ips '())))) + +(test-equal "endpoint-host-names" + ;; The first element of the pair the public Wireguard key associated to a + ;; host name. + '(("VlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XjoalC8=" . + "some.dynamic-dns.service:53281") + ("AlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XgoalC9=" . + "example.org")) + (endpoint-host-names %wireguard-peers)) + +(test-end "vpn-services")