fix relative path

* Add local_addr configuration for doh-server

This commit adds a `local_addr` string value to `doh-server.conf`, specifying the IP address and port from which outgoing calls to upstream DNS resolvers should originate. This value is set as the `udpClient`'s and `tcpClient`'s `Dialer.LocalAddr` when initializing a `NewServer`. If the value is left empty in `doh-server.conf`, it defaults to the first `listen` address (which in turn defaults to `"127.0.0.1:8053"`).

One use case for this would be if `doh-server` is proxying requests to a local DNS resolver (e.g. `unbound` or Pi-hole). Up to version 2.0.0, all DNS queries from `doh-server` are sent from `127.0.0.1` (even if the `listen` address is set to a different loopback IP address), making it hard to distinguish them from all other local DNS queries from the same machine in the query logs.

* Revert defaulting of local_addr to listen address

This commit reverts to the existing behavior when `conf.LocalAddr == ""`, i.e. letting `dns.Client` instantiate its own `Dialer` with the default local address.

* Fixup comment in configuration file

* Log errors from Dialer instantiation (e.g. if LocalAddr port is missing)

* Fixup other comment in configuration file

* Return error and log fatal

.gitignore

@@ -3,6 +3,7 @@
 *.dll
 *.so
 *.dylib
+build/
 
 # Test binary, build with `go test -c`
 *.test

contrib/package.sh

@@ -0,0 +1,173 @@
+#!/bin/bash 
+set -euo pipefail
+
+# This is a script used for automated packaging.
+# Debian maintainers please don't use this.
+# 
+# Environment assumption:
+#  * Ubuntu 16.04
+#  * run with normal user
+#  * sudo with no password
+#  * go and fpm is pre-installed
+#  * rpmbuild is required if you need rpm packages
+#
+# Compatible with Azure DevOps hosted Ubuntu 16.04 agent
+
+export DEBIAN_FRONTEND="noninteractive"
+export DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"/..
+export BUILD_BINARIESDIRECTORY="${BUILD_BINARIESDIRECTORY:-${DIR}/build/bin}"
+export BUILD_ARTIFACTSTAGINGDIRECTORY="${BUILD_ARTIFACTSTAGINGDIRECTORY:-${DIR}/build/packages}"
+export TMP_DIRECTORY="/tmp/dohbuild"
+export GOPATH="${GOPATH:-/tmp/go}"
+export GOBIN="${GOBIN:-/tmp/go/bin}"
+
+function prepare_env() {
+    echo "Checking dependencies"
+
+    if ! [ -x "$(command -v go)" ]; then
+        echo "Please install golang"
+        exit 1
+    fi
+
+    if [ -x "$(command -v apt-get)" ]; then
+        sudo apt-get -y update
+    fi
+
+    if ! [ -x "$(command -v rpmbuild)" ]; then
+        # TODO: correctly install rpmbuild
+        ! sudo apt-get -y install rpmbuild
+    fi
+
+    # if ! [ -x "$(command -v upx)" ]; then
+    #     sudo apt-get -y install upx
+    # fi
+
+    echo "Creating directories"
+
+    mkdir -p "${BUILD_BINARIESDIRECTORY}/nm-dispatcher"
+    mkdir -p "${BUILD_BINARIESDIRECTORY}/launchd"
+    mkdir -p "${BUILD_BINARIESDIRECTORY}/systemd"
+    mkdir -p "${BUILD_BINARIESDIRECTORY}/config"
+    mkdir -p "${BUILD_ARTIFACTSTAGINGDIRECTORY}"
+    mkdir -p "${TMP_DIRECTORY}"
+}
+
+function build_common() {
+    cp NetworkManager/dispatcher.d/* "${BUILD_BINARIESDIRECTORY}"/nm-dispatcher
+    cp launchd/*.plist "${BUILD_BINARIESDIRECTORY}"/launchd
+    cp systemd/*.service "${BUILD_BINARIESDIRECTORY}"/systemd
+    cp doh-server/doh-server.conf "${BUILD_BINARIESDIRECTORY}"/config
+    cp doh-client/doh-client.conf "${BUILD_BINARIESDIRECTORY}"/config
+}
+
+# used to get version
+function build_native() {
+    echo "Building a native binary..."
+
+    go build -ldflags="-s -w" -o ${BUILD_BINARIESDIRECTORY}/"${EXE}"-native
+}
+
+function build() {
+    echo "Building ${EXE} for OS=$1 ARCH=$2"
+    env GOOS="$1" GOARCH="$2" go build -ldflags="-s -w" -o ${BUILD_BINARIESDIRECTORY}/"${EXE}"-"$3"
+
+    # echo "Compressing executable"
+    # ! upx --ultra-brute ${BUILD_BINARIESDIRECTORY}/${EXE}-"$3" || true
+}
+
+function package() {
+    VERSION=$("${BUILD_BINARIESDIRECTORY}/${EXE}-native" --version | head -n 1 | cut -d" " -f2)
+    REVISION=$(git log --pretty=format:'%h' -n 1)
+
+    echo "Packaging ${EXE} ${VERSION} for OS=$1 ARCH=$2 TYPE=$3 DST=$4"
+
+    ! rm -rf "${TMP_DIRECTORY}"/*
+
+    mkdir -p "${TMP_DIRECTORY}"/usr/bin
+    cp "${BUILD_BINARIESDIRECTORY}"/"${EXE}"-"$3" "${TMP_DIRECTORY}"/usr/bin/"${EXE}"
+
+    mkdir -p "${TMP_DIRECTORY}"/usr/lib/systemd/system
+    cp "${BUILD_BINARIESDIRECTORY}"/systemd/"${EXE}".service "${TMP_DIRECTORY}"/usr/lib/systemd/system
+
+    mkdir -p "${TMP_DIRECTORY}"/etc/dns-over-https
+    cp "${BUILD_BINARIESDIRECTORY}"/config/"${EXE}".conf "${TMP_DIRECTORY}"/etc/dns-over-https
+
+    mkdir -p "${TMP_DIRECTORY}"/etc/NetworkManager/dispatcher.d
+    cp "${BUILD_BINARIESDIRECTORY}"/nm-dispatcher/"${EXE}" "${TMP_DIRECTORY}"/etc/NetworkManager/dispatcher.d
+
+    # call fpm
+    fpm --input-type dir \
+        --output-type $4 \
+        --chdir "${TMP_DIRECTORY}" \
+        --package "${BUILD_ARTIFACTSTAGINGDIRECTORY}" \
+        --name "${EXE}" \
+        --description "${DESCR}" \
+        --version "${VERSION}" \
+        --iteration "${REVISION}" \
+        --url "https://github.com/m13253/dns-over-https" \
+        --vendor "Star Brilliant <coder@poorlab.com>" \
+        --license "MIT License" \
+        --category "net" \
+        --maintainer "James Swineson <autopkg@public.swineson.me>" \
+        --architecture "$2" \
+        --force \
+        .
+}
+
+cd "${DIR}"/..
+prepare_env
+make deps
+build_common
+
+pushd doh-server
+export EXE="doh-server"
+export DESCR="DNS-over-HTTPS Server"
+
+build_native
+
+build linux amd64 linux-amd64
+package linux amd64 linux-amd64 deb
+! package linux amd64 linux-amd64 rpm
+package linux amd64 linux-amd64 pacman
+
+build linux arm linux-armhf
+package linux arm linux-armhf deb
+! package linux arm linux-armhf rpm
+package linux arm linux-armhf pacman
+
+build linux arm64 linux-arm64
+package linux arm64 linux-arm64 deb
+! package linux arm64 linux-arm64 rpm
+package linux arm64 linux-arm64 pacman
+
+# build darwin amd64 darwin-amd64
+# build windows 386 windows-x86.exe
+# build windows amd64 windows-amd64.exe
+popd
+
+pushd doh-client
+export EXE="doh-client"
+export DESCR="DNS-over-HTTPS Client"
+
+build_native
+
+build linux amd64 linux-amd64
+package linux amd64 linux-amd64 deb
+! package linux amd64 linux-amd64 rpm
+package linux amd64 linux-amd64 pacman
+
+build linux arm linux-armhf
+package linux arm linux-armhf deb
+! package linux arm linux-armhf rpm
+package linux arm linux-armhf pacman
+
+build linux arm64 linux-arm64
+package linux arm64 linux-arm64 deb
+! package linux arm64 linux-arm64 rpm
+package linux arm64 linux-arm64 pacman
+
+# build darwin amd64 darwin-amd64
+# build windows 386 windows-x86.exe
+# build windows amd64 windows-amd64.exe
+popd
+

doh-server/config.go

@@ -31,6 +31,7 @@ import (
 
 type config struct {
 	Listen           []string `toml:"listen"`
+	LocalAddr        string   `toml:"local_addr"`
 	Cert             string   `toml:"cert"`
 	Key              string   `toml:"key"`
 	Path             string   `toml:"path"`

doh-server/doh-server.conf

@@ -4,6 +4,10 @@ listen = [
     "[::1]:8053",
 ]
 
+# Local address and port for upstream DNS
+# If left empty, a local address is automatically chosen.
+local_addr = ""
+
 # TLS certification file
 # If left empty, plain-text HTTP will be used.
 # You are recommended to leave empty and to use a server load balancer (e.g.

doh-server/main.go

@@ -110,6 +110,9 @@ func main() {
 		conf.Verbose = true
 	}
 
-	server := NewServer(conf)
+	server, err := NewServer(conf)
+	if err != nil {
+		log.Fatalln(err)
+	}
 	_ = server.Start()
 }

doh-server/server.go

@@ -56,22 +56,41 @@ type DNSRequest struct {
 	errtext         string
 }
 
-func NewServer(conf *config) (s *Server) {
-	s = &Server{
+func NewServer(conf *config) (*Server, error) {
+	timeout := time.Duration(conf.Timeout) * time.Second
+	s := &Server{
 		conf: conf,
 		udpClient: &dns.Client{
 			Net:     "udp",
 			UDPSize: dns.DefaultMsgSize,
-			Timeout: time.Duration(conf.Timeout) * time.Second,
+			Timeout: timeout,
 		},
 		tcpClient: &dns.Client{
 			Net:     "tcp",
-			Timeout: time.Duration(conf.Timeout) * time.Second,
+			Timeout: timeout,
 		},
 		servemux: http.NewServeMux(),
 	}
+	if conf.LocalAddr != "" {
+		udpLocalAddr, err := net.ResolveUDPAddr("udp", conf.LocalAddr)
+		if err != nil {
+			return nil, err
+		}
+		tcpLocalAddr, err := net.ResolveTCPAddr("tcp", conf.LocalAddr)
+		if err != nil {
+			return nil, err
+		}
+		s.udpClient.Dialer = &net.Dialer{
+			Timeout:   timeout,
+			LocalAddr: udpLocalAddr,
+		}
+		s.tcpClient.Dialer = &net.Dialer{
+			Timeout:   timeout,
+			LocalAddr: tcpLocalAddr,
+		}
+	}
 	s.servemux.HandleFunc(conf.Path, s.handlerFunc)
-	return
+	return s, nil
 }
 
 func (s *Server) Start() error {