add install script for Linux

README.md

@@ -26,6 +26,11 @@ it can work as a `DNS-over-HTTPS`, `DNS-over-TLS` or `DNS-over-QUIC` server.
 
 ## How to install
 
+For Linux with systemd:
+```
+curl -fsSL https://raw.githubusercontent.com/AdguardTeam/dnsproxy/master/install_dnsproxy.sh | bash -s systemd
+```
+
 There are several options how to install `dnsproxy`.
 
 1. Grab the binary for your device/OS from the [Releases][releases] page.

install_dnsproxy.sh

@@ -0,0 +1,102 @@
+#!/bin/bash
+
+# Define the repository and tool name
+REPO_OWNER="AdguardTeam"
+REPO_NAME="dnsproxy"
+
+ARGS="--listen 0.0.0.0 --listen :: --port 5353 \
+    --bootstrap 8.8.8.8 --bootstrap 2606:4700:4700::1111 \
+    --fallback 9.9.9.9 --fallback 2620:fe::9 \
+    --upstream [/www.googleadservices.com/]8.8.8.8 --upstream [/ad.doubleclick.net/]8.8.8.8 \
+    --upstream https://dns.adguard.com/dns-query --upstream quic://dns.adguard.com \
+    --ratelimit 500 --cache --cache-optimistic --cache-size 2097152  --output /dev/null"
+
+# Fetch the latest release tag from GitHub API
+echo "Fetching the latest release information..."
+LATEST_TAG=$(curl -s "https://api.github.com/repos/$REPO_OWNER/$REPO_NAME/releases/latest" | grep '"tag_name":' | sed -E 's/.*"([^"]+)".*/\1/')
+if [ -z "$LATEST_TAG" ]; then
+    echo "Failed to fetch the latest release tag. Exiting."
+    exit 1
+fi
+
+# Detect system architecture
+ARCH=$(uname -m)
+case "$ARCH" in
+    x86_64) SYSTEM_ARCH="linux-amd64" ;;
+    aarch64) SYSTEM_ARCH="linux-arm64" ;;
+    armv7*) SYSTEM_ARCH="linux-arm7" ;;
+    *)
+        echo "Unsupported architecture: $ARCH. Exiting."
+        exit 1
+        ;;
+esac
+
+# Construct the download URL
+DOWNLOAD_URL="https://github.com/$REPO_OWNER/$REPO_NAME/releases/download/$LATEST_TAG/dnsproxy-$SYSTEM_ARCH-$LATEST_TAG.tar.gz"
+echo "Downloading dnsproxy from: $DOWNLOAD_URL"
+
+# Create a temporary directory for extraction
+TEMP_DIR=$(mktemp -d)
+
+# Download and extract the binary
+curl -sSL "$DOWNLOAD_URL" -o dnsproxy.tar.gz && \
+    tar -xzf dnsproxy.tar.gz -C "$TEMP_DIR" && \
+    rm -f dnsproxy.tar.gz
+
+# Move the binary to /usr/local/bin/
+echo "Installing dnsproxy to /usr/local/bin/"
+mv "$TEMP_DIR/$SYSTEM_ARCH/dnsproxy" /usr/local/bin/
+
+# Clean up the temporary directory
+rm -rf "$TEMP_DIR"
+
+# Check if the script was run with systemd
+if [[ "$1" == "systemd" ]]; then
+    if ! command -v systemctl 2>&1 >/dev/null
+    then
+        echo "Error: systemd is not available on this system"
+        exit 1
+    fi
+
+    echo "Setting up systemd service..."
+
+    SERVICE_CONTENT="[Unit]
+Description=DNSProxy - A fast DNS proxy with DoH/DoT support
+After=network.target
+
+[Service]
+ExecStart=/usr/local/bin/dnsproxy ${ARGS}
+Restart=always
+
+[Install]
+WantedBy=multi-user.target"
+
+    # Write the service file to /etc/systemd/system/dnsproxy.service
+    echo "$SERVICE_CONTENT" | tee /etc/systemd/system/dnsproxy.service > /dev/null
+
+    # Enable and start the service
+    systemctl daemon-reload
+    systemctl enable --now dnsproxy
+
+    # Check if systemd-resolved is running
+    if systemctl is-active --quiet systemd-resolved; then
+        # Backup the original resolved.conf file
+        cp /etc/systemd/resolved.conf /etc/systemd/resolved.conf.bak
+
+        # Modify resolved.conf to forward DNS queries to 127.0.0.1:5353
+        sed -i 's/^DNS=.*/DNS=127.0.0.1:5353/' /etc/systemd/resolved.conf
+
+        # Restart systemd-resolved to apply changes
+        systemctl restart systemd-resolved
+
+        echo "Configured systemd-resolved to forward DNS queries to dnsproxy at 127.0.0.1:5353"
+    else
+        echo "systemd-resolved is not running. Please manually configure your DNS to use the upstream server at 127.0.0.1:5353"
+    fi
+
+    echo ""
+    echo "dnsproxy systemd service has been installed and started with the args: ${ARGS}"
+else
+    echo "Successfully installed dnsproxy to /usr/local/bin/."
+    echo "You can now run 'dnsproxy --version' to verify the installation."
+fi