From 8639bdb81b962b299b545a85e6e867f1e281e55c Mon Sep 17 00:00:00 2001
From: lurchi <lurchi@strangeplace.net>
Date: Sun, 4 Nov 2018 22:27:57 +0100
Subject: [PATCH] initial commit

---
 homeserverdns-daemon | 170 +++++++++++++++++++++++++++++++++++++++++++
 homeserverdns-update | 104 ++++++++++++++++++++++++++
 homeserverdns.cfg    |  31 ++++++++
 3 files changed, 305 insertions(+)
 create mode 100755 homeserverdns-daemon
 create mode 100644 homeserverdns-update
 create mode 100644 homeserverdns.cfg

diff --git a/homeserverdns-daemon b/homeserverdns-daemon
new file mode 100755
index 0000000..8a1a490
--- /dev/null
+++ b/homeserverdns-daemon
@@ -0,0 +1,170 @@
+#!/run/current-system/sw/bin/bash
+
+# homeserverdns - https://ulrich.earth/code/homeserverdns
+#
+# Copyright (C) 2018  Christian Ulrich
+# 
+# This program 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.
+# 
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+readonly required_config_options=("protocol" "auth_key" "domains")
+readonly default_ttl=300
+readonly default_public_ip4_hook="upnpc -s | grep ExternalIPAddress | cut -d ' ' -f3"
+readonly default_update_hook="./homeserverdns-update"
+
+
+### () -> default_network_interface
+function get_interface {
+    ip -o -6 route show to default | cut -d " " -f5
+}
+
+
+### (ip_address) -> bool
+function is_unique_local_address {
+    prefix=$(echo $1 | cut -d ":" -f1)
+    [ "${prefix}" == "fd00" ] && echo true || echo false
+}
+
+
+### (ip_oneline_output) -> ip6_address
+function extract_ip6 {
+    ip_address=$(echo $1 | tr -s " " | cut -d " " -f4 | cut -d "/" -f1)
+    [ "$(is_unique_local_address $ip_address)" == false ] && echo $ip_address || echo ""
+}
+
+
+### Returns an IPv6 address extracted from a oneline output of ip monitor if
+### it's global, used for routing and still in use. Returns "" otherwise.
+### (ip_monitor_output) -> ip6_address
+function parse_ip_monitor_output {
+    filtered=$(echo $1 | grep -Ev '^Deleted|temporary|deprecated|noprefixroute|preferred_lft 0sec' | grep "scope global")
+    [ -n "${filtered}" ] && echo $(extract_ip6 "${filtered}") || echo ""
+}
+
+
+### (config) -> external_ip4_address
+function lookup_ip4 {
+    eval "declare -A config="${1#*=}
+    local public_ip4_hook=${config["public_ip4_hook"]}
+    echo $(eval ${public_ip4_hook:-$default_public_ip4_hook})
+}
+
+
+### () -> global_ip6_address
+function lookup_ip6 {
+    iface=$(get_interface)
+    ip_output=$(ip -6 -o address show dev $iface scope global -temporary -deprecated -noprefixroute | head -n1)
+    echo $(extract_ip6 "${ip_output}")
+}
+
+
+### (config_path) -> config
+function parse_config {
+    declare -A config
+    while IFS= read -r line
+    do
+        if [ -n "${line}" ] && [[ $line != \#* ]]; then
+            local key value
+            IFS="=" read -r key value <<< $line
+            [ -n "${key}" ] && [ -n "${value}" ] && config[$key]=$value
+        fi
+    done < $1
+    declare -p config
+}
+
+
+### utility function for joining strings
+### (delimiter, list) -> joined_list
+function join_by {
+    local IFS=$1
+    shift
+    echo "$*"
+}
+
+
+### utility function for splitting a full-qualified domain name
+### (fqdn) -> (record_name, second_level_domain)
+function split_domain {
+    local tokens=(${1//./ })
+    local token_count=${#tokens[*]}
+    local second_level_domain=${tokens[@]:$((token_count - 2))}
+    if [ "${token_count}" -gt 2 ]; then
+        local record_name=${tokens[@]:0:$((token_count - 2))}
+    else
+        local record_name=("@")
+    fi
+    echo $(join_by . ${record_name[@]})" "$(join_by . ${second_level_domain[@]})
+}
+
+
+### (ip4, ip6, config) -> log_output
+function update {
+    eval "declare -A config="${3#*=}
+    local domains=(${config["domains"]})
+    local update_hook=${config["update_hook"]}
+    export PROTOCOL=${config["protocol"]}
+    export API_ADDRESS=${config["api_address"]}
+    export USER=${config["user"]}
+    export AUTH_KEY=${config["auth_key"]}
+    #export IP4=$1
+    #export IP6=$2
+    export TTL=${config["ttl"]:-$default_ttl}
+    for domain in "${domains[@]}"; do
+        local record_name second_level_domain
+        read -r record_name second_level_domain <<< $(split_domain $domain)
+        export DOMAIN=$domain
+        export L2_DOMAIN=$second_level_domain
+        export RECORD_NAME=$record_name
+        echo "[$(date "+%Y-%m-%d %H:%M")] updating ${domain} ..."
+        if [ -n "$1" ]; then
+            echo -n "| setting A=$1 ... "
+            echo "status: "$(eval "IP4=$1 bash ${update_hook:-$default_update_hook}")
+        fi
+        if [ -n "$2" ]; then
+            echo -n "| setting AAAA=$2 ... "
+            echo "status: "$(eval "IP6=$2 bash ${update_hook:-$default_update_hook}")
+        fi
+    done
+}
+
+
+function main {
+    if [ "$#" -ne 1 ]; then
+        echo "usage: $0 CONFIG_FILE"
+        exit 1
+    fi
+    config=$(parse_config $1)
+    eval "declare -A config="${config#*=}
+    for key in "${required_config_options[@]}"; do
+        if [ -z "${config[$key]}" ]; then
+            echo "configuration is missing option \"${key}\"" >&2
+            exit 1
+        fi
+    done
+    local ip4=$(lookup_ip4 "$(declare -p config)")
+    local ip6=$(lookup_ip6)
+    update "${ip4}" "${ip6}" "$(declare -p config)"
+    ip -6 -o monitor address dev $(get_interface) |
+    while IFS= read -r line
+    do
+        ip4=$(lookup_ip4 "$(declare -p config)")
+        local new_ip6=$(parse_ip_monitor_output "${line}")
+        #echo "ip-monitor output was ${line}"
+        if [ -n "${new_ip6}" ] && [ "${new_ip6}" != "${ip6}" ]; then
+            ip6=$new_ip6
+            update "${ip4}" "${ip6}" "$(declare -p config)"
+        fi
+    done
+}
+
+main "$@"
diff --git a/homeserverdns-update b/homeserverdns-update
new file mode 100644
index 0000000..8bc2a5f
--- /dev/null
+++ b/homeserverdns-update
@@ -0,0 +1,104 @@
+#!/run/current-system/sw/bin/bash
+
+# homeserverdns - https://ulrich.earth/code/homeserverdns
+#
+# Copyright (C) 2018  Christian Ulrich
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# This script is called by homeserverdns-daemon for updating A/AAAA records.
+# These environment variables will be set by homeserverdns-daemon:
+#
+# PROTOCOL      protocol name (gandi|dyndns|httpnet)
+# API_ADDRESS   address for API requests, required for dnydns protocol
+# USER          user name for authentication at the API
+# AUTH_KEY      authentication token for authentication at the API
+# DOMAIN        fqdn for which A/AAAA records will be set 
+# L2_DOMAIN     second-level domain for which A/AAAA records will be set
+# RECORD_NAME   name of the record to be set
+# IP4           new value of the A record (IP4 or IP6 will be set exclusively)
+# IP6           new value of the AAAA record (IP4 or IP6 will be set exclusively)
+# TTL           new TTL value for the A/AAAA records, required for gandi protocol
+
+
+### gandi.net LiveDNS API
+### () -> status_code
+function update_gandi {
+    local url="https://dns.api.gandi.net/api/v5/domains/${L2_DOMAIN}/records/${RECORD_NAME}"
+    local ip=""
+    if [ -n "${IP4}" ]; then
+        url="${url}/A" 
+        ip=$IP4
+    elif [ -n "${IP6}" ]; then
+        url="${url}/AAAA"
+        ip=$IP6
+    fi
+    status=$(curl -o /dev/null -s -w "%{http_code}\n" \
+                  -X PUT \
+                  -H "Content-Type:application/json" \
+                  -H "X-Api-Key:${AUTH_KEY}" \
+                  -d "{\"rrset_ttl\":${TTL},\"rrset_values\":[\"${ip}\"]}" \
+                  $url)
+    echo "${status}"
+}
+
+
+# FIXME: untested
+### http.net DNS API v1
+### () -> status_code
+function update_httpnet {
+    local current_ip4=$(dig A +short $DOMAIN)
+    local current_ip6=$(dig AAAA +short $DOMAIN)
+    local url="https://partner.http.net/api/dns/v1/json/zoneUpdate"
+    local items_add=""
+    local items_delete=""
+    if [ -n "${IP4}" ]; then
+        items_add="{\"name\":\"${DOMAIN}\",\"type\":\"A\",\"content\":\"${IP4}\",\"ttl\":\"${TTL}\"}"
+    elif [ -n "${IP6}" ]; then
+        items_add="{\"name\":\"${DOMAIN}\",\"type\":\"AAAA\",\"content\":\"${IP6}\",\"ttl\":\"${TTL}\"}"
+    fi
+    if [ -n "${current_ip4}" ]; then
+        items_delete="{\"name\":\"${DOMAIN}\",\"type\":\"A\",\"content\":\"${current_ip4}\"}"
+    fi
+    if [ -n "${current_ip6}" ]; then
+        items_delete="{\"name\":\"${DOMAIN}\",\"type\":\"AAAA\",\"content\":\"${current_ip6}\"}"
+    fi
+    status=$(curl -o /dev/null -s -w "%{http_code}\n" \
+                  -X PUT \
+                  -d "{\"authToken\":\"${AUTH_KEY}\"," \
+                     "\"zoneConfig\":{\"name\":\"${L2_DOMAIN}\"}," \
+                     "\"recordsToAdd\":[${items_add}]," \
+                     "\"recordsToDelete\":[${items_delete}]}" \
+                  $url)
+    echo "${status}"
+}
+
+
+# FIXME: untested
+### dyndns API v2/v3 API
+### () -> status_code
+function update_dyndns {
+    local hostname=${L2_DOMAIN}
+    if [ "${RECORD_NAME}" != "@" ]; then
+        local hostname=$DOMAIN
+    fi
+    local address=${IP4:-$IP6}
+    local url="https://${USER}:${AUTH_KEY}@${API_ADDRESS}?hostname=${hostname}&myip=${address}"
+    status=$(curl -o /dev/null -s -w "%{http_code}\n" $url)
+    echo "${url} ${status}"
+}
+
+
+eval "update_${PROTOCOL}"
diff --git a/homeserverdns.cfg b/homeserverdns.cfg
new file mode 100644
index 0000000..3128b81
--- /dev/null
+++ b/homeserverdns.cfg
@@ -0,0 +1,31 @@
+# Protocol name, may be left empty when using a custom update_hook.
+# The default update_hook supports: gandi, dyndns
+protocol=
+
+# The command to be called to determine our public IP address. By default UPNP
+# will be used
+public_ip4_hook=
+
+# The command to be called when an IP change is detected. Environment variables
+# will be set when calling it (for documentation see homeserverdns-update).
+# Default: ./homeserverdns-update
+update_hook=
+
+# The address of the API, required for dyndns protocol.
+# Example: dyndns.strato.com/nic/update
+api_address=
+
+# User name for authentication at the API (not all protocols require this).
+user=
+
+# Token used for authentication at the API
+auth_key=
+
+# Time-to-live for the A/AAAA records (not all protocols support this).
+# default: 300
+ttl=
+
+# A space separated list of the domains for which the A/AAAA records shall be
+# updated. For each domain the update_hook will be called.
+domains=
+