contrib: add reresolve-dns

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2017-10-31 16:15:19 +01:00
parent 2207025c2f
commit 225882ccc4
2 changed files with 48 additions and 0 deletions

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reresolve-dns
=============
Run this script from cron every thirty seconds or so, and it will ensure
that if, when using a dynamic DNS service, the DNS entry for a hosts
changes, the kernel will get the update to the DNS entry.
This works by parsing configuration files, and simply running:
$ wg set wg0 peer ... endpoint ...

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#!/bin/bash
set -e
shopt -s nocasematch
shopt -s extglob
export LC_ALL=C
CONFIG_FILE="$1"
[[ $CONFIG_FILE =~ ^[a-zA-Z0-9_=+.-]{1,16}$ ]] && CONFIG_FILE="/etc/wireguard/$CONFIG_FILE.conf"
[[ $CONFIG_FILE =~ /?([a-zA-Z0-9_=+.-]{1,16})\.conf$ ]]
INTERFACE="${BASH_REMATCH[1]}"
process_peer() {
[[ $PEER_SECTION -ne 1 || -z $PUBLIC_KEY || -z $ENDPOINT ]] && return 0
[[ $(wg show "$INTERFACE" latest-handshakes) =~ ^${PUBLIC_KEY//+/\\+}\ ([0-9]+)$ ]] || return 0
(( ($(date +%s) - ${BASH_REMATCH[1]}) > 135 )) || return 0
wg set "$INTERFACE" peer "$PUBLIC_KEY" endpoint "$ENDPOINT"
reset_peer_section
}
reset_peer_section() {
PEER_SECTION=0
PUBLIC_KEY=""
ENDPOINT=""
}
reset_peer_section
while read -r line || [[ -n $line ]]; do
key="${line%%=*}"; key="${key##*( )}"; key="${key%%*( )}"
value="${line#*=}"; value="${value##*( )}"; value="${value%%*( )}"
[[ $key == "["* ]] && { process_peer; reset_peer_section; }
[[ $key == "[Peer]" ]] && PEER_SECTION=1
if [[ $PEER_SECTION -eq 1 ]]; then
case "$key" in
PublicKey) PUBLIC_KEY="$value"; continue ;;
Endpoint) ENDPOINT="$value"; continue ;;
esac
fi
done < "$CONFIG_FILE"
process_peer