Add Android aarch64/armv7 targets to release builds

Adds ARMv8 (aarch64-linux-android) and ARMv7 (armv7-linux-androideabi)
builds for Termux/Android using the Android NDK r27c. Release artifacts
now include btest-android-aarch64.tar.gz and btest-android-armv7.tar.gz.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Install dependencies
         run: |
           apt-get update && apt-get install -y --no-install-recommends \
-            git curl jq ca-certificates zip \
+            git curl jq ca-certificates zip unzip \
             musl-tools \
             gcc-aarch64-linux-gnu \
             gcc-arm-linux-gnueabihf \
@@ -23,7 +23,14 @@ jobs:
             x86_64-unknown-linux-musl \
             aarch64-unknown-linux-musl \
             armv7-unknown-linux-musleabihf \
-            x86_64-pc-windows-gnu
+            x86_64-pc-windows-gnu \
+            aarch64-linux-android \
+            armv7-linux-androideabi
+          # Install Android NDK for cross-compilation
+          NDK_VER=r27c
+          curl -sL https://dl.google.com/android/repository/android-ndk-${NDK_VER}-linux.zip -o /tmp/ndk.zip
+          unzip -q /tmp/ndk.zip -d /opt && rm /tmp/ndk.zip
+          export ANDROID_NDK_HOME=/opt/android-ndk-${NDK_VER}
 
       - name: Ensure code is present
         run: |
@@ -47,6 +54,12 @@ jobs:
 
           [target.x86_64-pc-windows-gnu]
           linker = "x86_64-w64-mingw32-gcc"
+
+          [target.aarch64-linux-android]
+          linker = "/opt/android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android35-clang"
+
+          [target.armv7-linux-androideabi]
+          linker = "/opt/android-ndk-r27c/toolchains/llvm/prebuilt/linux-x86_64/bin/armv7a-linux-androideabi35-clang"
           TOML
 
       - name: Build Linux x86_64
@@ -61,6 +74,12 @@ jobs:
       - name: Build Windows x86_64
         run: cargo build --release --target x86_64-pc-windows-gnu
 
+      - name: Build Android aarch64 (ARMv8)
+        run: cargo build --release --target aarch64-linux-android
+
+      - name: Build Android armv7 (ARMv7)
+        run: cargo build --release --target armv7-linux-androideabi
+
       - name: Package all
         run: |
           mkdir -p /artifacts
@@ -81,6 +100,14 @@ jobs:
           zip /artifacts/btest-windows-x86_64.zip btest.exe
           cd -
 
+          cd target/aarch64-linux-android/release
+          tar czf /artifacts/btest-android-aarch64.tar.gz btest
+          cd -
+
+          cd target/armv7-linux-androideabi/release
+          tar czf /artifacts/btest-android-armv7.tar.gz btest
+          cd -
+
           cd /artifacts
           sha256sum * > checksums-sha256.txt
           cat checksums-sha256.txt
@@ -103,6 +130,8 @@ jobs:
           | Linux | aarch64 (RPi 64-bit) | btest-linux-aarch64.tar.gz |
           | Linux | armv7 (RPi 32-bit) | btest-linux-armv7.tar.gz |
           | Windows | x86_64 | btest-windows-x86_64.zip |
+          | Android | aarch64 (ARMv8, Termux) | btest-android-aarch64.tar.gz |
+          | Android | armv7 (ARMv7, Termux) | btest-android-armv7.tar.gz |
           | macOS | aarch64 / x86_64 | Run \`scripts/build-macos-release.sh --upload ${TAG}\` |
           | Docker | x86_64 | \`docker pull ${REGISTRY}/manawenuz/btest-rs:${TAG}\` |
 

Cargo.toml

@@ -16,6 +16,14 @@ path = "src/lib.rs"
 name = "btest"
 path = "src/main.rs"
 
+[[bin]]
+name = "btest-client"
+path = "src/bin/client_only.rs"
+
+[[bin]]
+name = "btest-server"
+path = "src/bin/server_only.rs"
+
 [[bin]]
 name = "btest-server-pro"
 path = "src/server_pro/main.rs"
@@ -54,3 +62,9 @@ opt-level = 3
 lto = true
 strip = true
 codegen-units = 1
+
+# Minimal size profile for embedded/OpenWrt targets
+[profile.release-small]
+inherits = "release"
+opt-level = "z"
+panic = "abort"

deploy/openwrt/Makefile

@@ -0,0 +1,57 @@
+# OpenWrt package Makefile for btest-rs
+#
+# To build:
+#   1. Clone the OpenWrt SDK for your target
+#   2. Copy this directory to package/btest-rs/ in the SDK
+#   3. Run: make package/btest-rs/compile V=s
+#
+# Or use the pre-built binary approach (see build-ipk.sh)
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=btest-rs
+PKG_VERSION:=0.6.0
+PKG_RELEASE:=1
+
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://github.com/manawenuz/btest-rs/archive/refs/tags/v$(PKG_VERSION).tar.gz
+PKG_HASH:=skip
+
+PKG_BUILD_DEPENDS:=rust/host
+PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/btest-rs
+  SECTION:=net
+  CATEGORY:=Network
+  TITLE:=MikroTik Bandwidth Test server and client
+  URL:=https://github.com/manawenuz/btest-rs
+  DEPENDS:=
+  PKGARCH:=$(ARCH)
+endef
+
+define Package/btest-rs/description
+  A Rust reimplementation of the MikroTik Bandwidth Test (btest) protocol.
+  Supports TCP/UDP, IPv4/IPv6, EC-SRP5 and MD5 authentication,
+  multi-connection, syslog, CSV output, and CPU monitoring.
+endef
+
+define Build/Compile
+	cd $(PKG_BUILD_DIR) && \
+	CARGO_TARGET_DIR=$(PKG_BUILD_DIR)/target \
+	cargo build --release --target $(RUSTC_TARGET)
+endef
+
+define Package/btest-rs/install
+	$(INSTALL_DIR) $(1)/usr/bin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/target/$(RUSTC_TARGET)/release/btest $(1)/usr/bin/btest
+
+	$(INSTALL_DIR) $(1)/etc/init.d
+	$(INSTALL_BIN) ./files/btest.init $(1)/etc/init.d/btest
+
+	$(INSTALL_DIR) $(1)/etc/config
+	$(INSTALL_CONF) ./files/btest.config $(1)/etc/config/btest
+endef
+
+$(eval $(call BuildPackage,btest-rs))

deploy/openwrt/build-ipk.sh

@@ -0,0 +1,117 @@
+#!/usr/bin/env bash
+# Build an OpenWrt .ipk package from a pre-built static binary.
+# No OpenWrt SDK needed — just packages the binary with metadata.
+#
+# Usage:
+#   ./deploy/openwrt/build-ipk.sh <arch> [binary-path]
+#
+# Examples:
+#   ./deploy/openwrt/build-ipk.sh x86_64 dist/btest           # from cross-compiled binary
+#   ./deploy/openwrt/build-ipk.sh aarch64 dist/btest           # for RPi/ARM64 routers
+#   ./deploy/openwrt/build-ipk.sh mipsel target/release/btest  # for MIPS little-endian
+#
+# Supported architectures: x86_64, aarch64, arm_cortex-a7, mipsel_24kc, mips_24kc
+set -euo pipefail
+
+cd "$(dirname "$0")/../.."
+
+ARCH="${1:?Usage: $0 <arch> [binary-path]}"
+BINARY="${2:-dist/btest}"
+VERSION="0.6.0"
+PKG_NAME="btest-rs"
+OUTPUT_DIR="dist"
+
+if [ ! -f "$BINARY" ]; then
+    echo "Error: binary not found at $BINARY"
+    echo "Build it first: cargo build --release --target <target>"
+    exit 1
+fi
+
+mkdir -p "$OUTPUT_DIR"
+WORKDIR=$(mktemp -d)
+trap "rm -rf $WORKDIR" EXIT
+
+echo "=== Building ${PKG_NAME}_${VERSION}_${ARCH}.ipk ==="
+
+# Create package structure
+mkdir -p "$WORKDIR/data/usr/bin"
+mkdir -p "$WORKDIR/data/etc/init.d"
+mkdir -p "$WORKDIR/data/etc/config"
+mkdir -p "$WORKDIR/control"
+
+# Install files
+cp "$BINARY" "$WORKDIR/data/usr/bin/btest"
+chmod 755 "$WORKDIR/data/usr/bin/btest"
+cp deploy/openwrt/files/btest.init "$WORKDIR/data/etc/init.d/btest"
+chmod 755 "$WORKDIR/data/etc/init.d/btest"
+cp deploy/openwrt/files/btest.config "$WORKDIR/data/etc/config/btest"
+
+# Calculate installed size
+INSTALLED_SIZE=$(du -sk "$WORKDIR/data" | awk '{print $1}')
+
+# Control file
+cat > "$WORKDIR/control/control" << EOF
+Package: ${PKG_NAME}
+Version: ${VERSION}-1
+Depends: libc
+Source: https://github.com/manawenuz/btest-rs
+License: MIT AND Apache-2.0
+Section: net
+SourceName: ${PKG_NAME}
+Maintainer: Siavash Sameni <manwe@manko.yoga>
+Architecture: ${ARCH}
+Installed-Size: ${INSTALLED_SIZE}
+Description: MikroTik Bandwidth Test server and client
+ A Rust reimplementation of the MikroTik btest protocol.
+ Supports TCP/UDP, EC-SRP5 and MD5 auth, IPv4/IPv6.
+EOF
+
+# Post-install script
+cat > "$WORKDIR/control/postinst" << 'EOF'
+#!/bin/sh
+[ "${IPKG_NO_SCRIPT}" = "1" ] && exit 0
+/etc/init.d/btest enable 2>/dev/null || true
+exit 0
+EOF
+chmod 755 "$WORKDIR/control/postinst"
+
+# Pre-remove script
+cat > "$WORKDIR/control/prerm" << 'EOF'
+#!/bin/sh
+/etc/init.d/btest stop 2>/dev/null || true
+/etc/init.d/btest disable 2>/dev/null || true
+exit 0
+EOF
+chmod 755 "$WORKDIR/control/prerm"
+
+# Conffiles
+cat > "$WORKDIR/control/conffiles" << EOF
+/etc/config/btest
+EOF
+
+# Build the .ipk (it's just a tar.gz of tar.gz's)
+cd "$WORKDIR"
+
+# Create data.tar.gz
+(cd data && tar czf ../data.tar.gz .)
+
+# Create control.tar.gz
+(cd control && tar czf ../control.tar.gz .)
+
+# Create debian-binary
+echo "2.0" > debian-binary
+
+# Package it all
+tar czf "${PKG_NAME}_${VERSION}-1_${ARCH}.ipk" debian-binary control.tar.gz data.tar.gz
+
+cd -
+cp "$WORKDIR/${PKG_NAME}_${VERSION}-1_${ARCH}.ipk" "$OUTPUT_DIR/"
+
+echo ""
+echo "Package: $OUTPUT_DIR/${PKG_NAME}_${VERSION}-1_${ARCH}.ipk"
+ls -lh "$OUTPUT_DIR/${PKG_NAME}_${VERSION}-1_${ARCH}.ipk"
+echo ""
+echo "Install on OpenWrt:"
+echo "  scp $OUTPUT_DIR/${PKG_NAME}_${VERSION}-1_${ARCH}.ipk root@router:/tmp/"
+echo "  ssh root@router 'opkg install /tmp/${PKG_NAME}_${VERSION}-1_${ARCH}.ipk'"
+echo "  ssh root@router '/etc/init.d/btest enable && /etc/init.d/btest start'"

deploy/openwrt/files/btest.config

@@ -0,0 +1,7 @@
+config server
+    option enabled '0'
+    option port '2000'
+    option auth_user ''
+    option auth_pass ''
+    option ecsrp5 '0'
+    option syslog ''

deploy/openwrt/files/btest.init

@@ -0,0 +1,34 @@
+#!/bin/sh /etc/rc.common
+# btest-rs OpenWrt init script
+
+START=90
+STOP=10
+
+USE_PROCD=1
+
+start_service() {
+    local enabled port auth_user auth_pass ecsrp5 syslog
+
+    config_load btest
+    config_get_bool enabled server enabled 0
+    [ "$enabled" -eq 0 ] && return
+
+    config_get port server port 2000
+    config_get auth_user server auth_user ''
+    config_get auth_pass server auth_pass ''
+    config_get_bool ecsrp5 server ecsrp5 0
+    config_get syslog server syslog ''
+
+    procd_open_instance
+    procd_set_param command /usr/bin/btest -s -P "$port"
+
+    [ -n "$auth_user" ] && procd_append_param command -a "$auth_user"
+    [ -n "$auth_pass" ] && procd_append_param command -p "$auth_pass"
+    [ "$ecsrp5" -eq 1 ] && procd_append_param command --ecsrp5
+    [ -n "$syslog" ] && procd_append_param command --syslog "$syslog"
+
+    procd_set_param respawn
+    procd_set_param stdout 1
+    procd_set_param stderr 1
+    procd_close_instance
+}

src/bandwidth.rs

@@ -20,6 +20,9 @@ pub struct BandwidthState {
     pub intervals: AtomicU32,
     /// Remote peer's CPU usage (received via status messages)
     pub remote_cpu: AtomicU8,
+    /// Remaining byte budget (TX + RX combined). When this reaches 0 the test
+    /// stops immediately. u64::MAX means unlimited (default for non-pro server).
+    pub byte_budget: AtomicU64,
 }
 
 impl BandwidthState {
@@ -38,6 +41,7 @@ impl BandwidthState {
             total_lost_packets: AtomicU64::new(0),
             intervals: AtomicU32::new(0),
             remote_cpu: AtomicU8::new(0),
+            byte_budget: AtomicU64::new(u64::MAX),
         })
     }
 
@@ -50,6 +54,29 @@ impl BandwidthState {
         self.intervals.fetch_add(1, Relaxed);
     }
 
+    /// Try to spend `amount` bytes from the budget. Returns `true` if allowed,
+    /// `false` if the budget is exhausted (and sets `running = false`).
+    #[inline]
+    pub fn spend_budget(&self, amount: u64) -> bool {
+        use std::sync::atomic::Ordering::{Relaxed, SeqCst};
+        // Fast path: unlimited budget (non-pro server)
+        let current = self.byte_budget.load(Relaxed);
+        if current == u64::MAX {
+            return true;
+        }
+        if current < amount {
+            self.running.store(false, SeqCst);
+            return false;
+        }
+        self.byte_budget.fetch_sub(amount, Relaxed);
+        true
+    }
+
+    /// Set the byte budget (total bytes allowed for the entire test).
+    pub fn set_budget(&self, budget: u64) {
+        self.byte_budget.store(budget, std::sync::atomic::Ordering::SeqCst);
+    }
+
     /// Get summary for syslog reporting.
     pub fn summary(&self) -> (u64, u64, u64, u32) {
         use std::sync::atomic::Ordering::Relaxed;

src/bin/client_only.rs

@@ -0,0 +1,127 @@
+//! btest-client: minimal bandwidth test client for embedded/OpenWrt systems.
+//!
+//! Stripped-down client that connects to MikroTik btest servers.
+//! No server mode, no syslog, smaller binary footprint.
+//!
+//! Build: cargo build --profile release-small --bin btest-client
+
+use clap::Parser;
+use std::sync::atomic::Ordering;
+
+#[derive(Parser)]
+#[command(name = "btest-client", about = "MikroTik Bandwidth Test client", version)]
+struct Cli {
+    /// Server address to connect to
+    #[arg(short = 'c', long = "client", required = true)]
+    host: String,
+
+    /// Transmit data (upload)
+    #[arg(short = 't', long = "transmit")]
+    transmit: bool,
+
+    /// Receive data (download)
+    #[arg(short = 'r', long = "receive")]
+    receive: bool,
+
+    /// Use UDP
+    #[arg(short = 'u', long = "udp")]
+    udp: bool,
+
+    /// Bandwidth limit (e.g., 100M)
+    #[arg(short = 'b', long = "bandwidth")]
+    bandwidth: Option<String>,
+
+    /// Port
+    #[arg(short = 'P', long = "port", default_value_t = 2000)]
+    port: u16,
+
+    /// Username
+    #[arg(short = 'a', long = "authuser")]
+    auth_user: Option<String>,
+
+    /// Password
+    #[arg(short = 'p', long = "authpass")]
+    auth_pass: Option<String>,
+
+    /// NAT mode
+    #[arg(short = 'n', long = "nat")]
+    nat: bool,
+
+    /// Duration in seconds (0=unlimited)
+    #[arg(short = 'd', long = "duration", default_value_t = 0)]
+    duration: u64,
+
+    /// Verbose
+    #[arg(short = 'v', long = "verbose", action = clap::ArgAction::Count)]
+    verbose: u8,
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let cli = Cli::parse();
+
+    let filter = match cli.verbose {
+        0 => "info",
+        1 => "debug",
+        _ => "trace",
+    };
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new(filter)),
+        )
+        .with_target(false)
+        .init();
+
+    btest_rs::cpu::start_sampler();
+
+    if !cli.transmit && !cli.receive {
+        eprintln!("Error: specify -t (transmit) and/or -r (receive)");
+        std::process::exit(1);
+    }
+
+    let direction = match (cli.transmit, cli.receive) {
+        (true, false) => btest_rs::protocol::CMD_DIR_RX,
+        (false, true) => btest_rs::protocol::CMD_DIR_TX,
+        (true, true) => btest_rs::protocol::CMD_DIR_BOTH,
+        _ => unreachable!(),
+    };
+
+    let bw = match &cli.bandwidth {
+        Some(b) => btest_rs::bandwidth::parse_bandwidth(b)?,
+        None => 0,
+    };
+
+    let (tx_speed, rx_speed) = match direction {
+        btest_rs::protocol::CMD_DIR_TX => (bw, 0),
+        btest_rs::protocol::CMD_DIR_RX => (0, bw),
+        _ => (bw, bw),
+    };
+
+    let state = btest_rs::bandwidth::BandwidthState::new();
+    let state_clone = state.clone();
+
+    let host = cli.host.clone();
+    let client_fut = btest_rs::client::run_client(
+        &host, cli.port, direction, cli.udp,
+        tx_speed, rx_speed,
+        cli.auth_user, cli.auth_pass, cli.nat,
+        state_clone,
+    );
+
+    if cli.duration > 0 {
+        match tokio::time::timeout(
+            std::time::Duration::from_secs(cli.duration),
+            client_fut,
+        ).await {
+            Ok(r) => { let _ = r?; }
+            Err(_) => {
+                state.running.store(false, Ordering::SeqCst);
+            }
+        }
+    } else {
+        let _ = client_fut.await?;
+    }
+
+    Ok(())
+}

src/bin/server_only.rs

@@ -0,0 +1,62 @@
+//! btest-server: minimal bandwidth test server for embedded/OpenWrt systems.
+//!
+//! Stripped-down server that accepts MikroTik client connections.
+//! No client mode, no syslog, no CSV, smaller binary footprint.
+//!
+//! Build: cargo build --profile release-small --bin btest-server
+
+use clap::Parser;
+
+#[derive(Parser)]
+#[command(name = "btest-server", about = "MikroTik Bandwidth Test server", version)]
+struct Cli {
+    /// Port
+    #[arg(short = 'P', long = "port", default_value_t = 2000)]
+    port: u16,
+
+    /// IPv4 listen address
+    #[arg(long = "listen", default_value = "0.0.0.0")]
+    listen_addr: String,
+
+    /// Username
+    #[arg(short = 'a', long = "authuser")]
+    auth_user: Option<String>,
+
+    /// Password
+    #[arg(short = 'p', long = "authpass")]
+    auth_pass: Option<String>,
+
+    /// Use EC-SRP5 authentication
+    #[arg(long = "ecsrp5")]
+    ecsrp5: bool,
+
+    /// Verbose
+    #[arg(short = 'v', long = "verbose", action = clap::ArgAction::Count)]
+    verbose: u8,
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let cli = Cli::parse();
+
+    let filter = match cli.verbose {
+        0 => "info",
+        1 => "debug",
+        _ => "trace",
+    };
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new(filter)),
+        )
+        .with_target(false)
+        .init();
+
+    btest_rs::cpu::start_sampler();
+
+    let v4 = if cli.listen_addr.eq_ignore_ascii_case("none") { None } else { Some(cli.listen_addr) };
+
+    tracing::info!("btest-server starting on port {}", cli.port);
+    btest_rs::server::run_server(cli.port, cli.auth_user, cli.auth_pass, cli.ecsrp5, v4, None).await?;
+    Ok(())
+}

src/server.rs

@@ -366,6 +366,24 @@ async fn handle_client(
 
 // --- TCP Test Server ---
 
+/// Public TX task for multi-connection use by server_pro.
+pub async fn tcp_tx_task(
+    writer: tokio::net::tcp::OwnedWriteHalf,
+    tx_size: usize,
+    tx_speed: u32,
+    state: Arc<BandwidthState>,
+) {
+    tcp_tx_loop(writer, tx_size, tx_speed, state).await;
+}
+
+/// Public RX task for multi-connection use by server_pro.
+pub async fn tcp_rx_task(
+    reader: tokio::net::tcp::OwnedReadHalf,
+    state: Arc<BandwidthState>,
+) {
+    tcp_rx_loop(reader, state).await;
+}
+
 /// Run a TCP bandwidth test on an already-authenticated stream.
 /// Public API for use by server_pro.
 pub async fn run_tcp_test(
@@ -451,9 +469,22 @@ async fn run_tcp_test_inner(stream: TcpStream, cmd: Command, state: Arc<Bandwidt
     Ok(state.summary())
 }
 
+/// Public API for multi-connection TCP test with external state. Used by server_pro.
+pub async fn run_tcp_multiconn_test(
+    streams: Vec<TcpStream>,
+    cmd: Command,
+    state: Arc<BandwidthState>,
+) -> Result<(u64, u64, u64, u32)> {
+    run_tcp_multiconn_inner(streams, cmd, state).await
+}
+
 /// TCP multi-connection.
 async fn run_tcp_multiconn_server(streams: Vec<TcpStream>, cmd: Command) -> Result<(u64, u64, u64, u32)> {
     let state = BandwidthState::new();
+    run_tcp_multiconn_inner(streams, cmd, state).await
+}
+
+async fn run_tcp_multiconn_inner(streams: Vec<TcpStream>, cmd: Command, state: Arc<BandwidthState>) -> Result<(u64, u64, u64, u32)> {
     let tx_size = cmd.tx_size as usize;
     let server_should_tx = cmd.server_tx();
     let server_should_rx = cmd.server_rx();
@@ -564,6 +595,9 @@ async fn tcp_tx_loop_inner(
             next_status = Instant::now() + Duration::from_secs(1);
         }
 
+        if !state.spend_budget(tx_size as u64) {
+            break;
+        }
         if writer.write_all(&packet).await.is_err() {
             state.running.store(false, Ordering::SeqCst);
             break;
@@ -600,6 +634,9 @@ async fn tcp_rx_loop(mut reader: tokio::net::tcp::OwnedReadHalf, state: Arc<Band
                 break;
             }
             Ok(n) => {
+                if !state.spend_budget(n as u64) {
+                    break;
+                }
                 state.rx_bytes.fetch_add(n as u64, Ordering::Relaxed);
             }
         }
@@ -796,6 +833,10 @@ async fn udp_tx_loop(
     let mut consecutive_errors: u32 = 0;
 
     while state.running.load(Ordering::Relaxed) {
+        if !state.spend_budget(tx_size as u64) {
+            break;
+        }
+
         packet[0..4].copy_from_slice(&seq.to_be_bytes());
 
         let result = if multi_conn {
@@ -871,6 +912,9 @@ async fn udp_rx_loop(socket: &UdpSocket, state: Arc<BandwidthState>) {
         // (multi-connection MikroTik sends from multiple ports)
         match tokio::time::timeout(Duration::from_secs(5), socket.recv_from(&mut buf)).await {
             Ok(Ok((n, _src))) if n >= 4 => {
+                if !state.spend_budget(n as u64) {
+                    break;
+                }
                 state.rx_bytes.fetch_add(n as u64, Ordering::Relaxed);
                 state.rx_packets.fetch_add(1, Ordering::Relaxed);
 

src/server_pro/enforcer.rs

@@ -342,4 +342,70 @@ mod tests {
         let (ip_in, ip_out) = db.get_ip_daily_usage("127.0.0.1").unwrap();
         assert!(ip_in + ip_out > 0, "IP usage should be recorded");
     }
+
+    #[test]
+    fn test_remaining_budget_calculation() {
+        let (db, qm) = setup_test_db();
+        let ip: IpAddr = "10.0.0.1".parse().unwrap();
+
+        // No usage yet: budget = min(daily=1000, weekly=5000, monthly=10000, ip_daily=500, ...)
+        // IP daily combined = 500 is the smallest
+        let budget = qm.remaining_budget("testuser", &ip);
+        assert_eq!(budget, 500, "budget should be min of all limits (ip_daily=500)");
+
+        // Use record_usage which properly records combined + directional
+        // inbound=200, outbound=200 → combined = 400
+        qm.record_usage("testuser", "10.0.0.1", 200, 200);
+
+        // IP daily combined: 500 - 400 = 100 remaining
+        // IP daily inbound: 500 - 200 = 300 remaining
+        // IP daily outbound: 500 - 200 = 300 remaining
+        // User daily: 1000 - 400 = 600 remaining
+        let budget = qm.remaining_budget("testuser", &ip);
+        assert_eq!(budget, 100, "budget should reflect IP combined remaining (100)");
+    }
+
+    #[test]
+    fn test_budget_zero_when_exhausted() {
+        let (db, qm) = setup_test_db();
+        let ip: IpAddr = "10.0.0.2".parse().unwrap();
+
+        // Exhaust user daily quota (1000 bytes)
+        db.record_usage("testuser", 600, 500).unwrap(); // 1100 > 1000
+
+        let budget = qm.remaining_budget("testuser", &ip);
+        assert_eq!(budget, 0, "budget should be 0 when user daily quota is exhausted");
+    }
+
+    #[test]
+    fn test_byte_budget_stops_transfer() {
+        let state = BandwidthState::new();
+
+        // Set a 1000-byte budget
+        state.set_budget(1000);
+
+        // Spend 500 bytes — should succeed
+        assert!(state.spend_budget(500));
+
+        // Spend another 400 — should succeed (100 remaining)
+        assert!(state.spend_budget(400));
+
+        // Spend 200 — should fail (only 100 remaining)
+        assert!(!state.spend_budget(200));
+
+        // running should be false
+        assert!(!state.running.load(Ordering::Relaxed));
+    }
+
+    #[test]
+    fn test_unlimited_budget_always_succeeds() {
+        let state = BandwidthState::new();
+        // Default budget is u64::MAX (unlimited)
+
+        // Should always succeed
+        for _ in 0..1000 {
+            assert!(state.spend_budget(1_000_000_000));
+        }
+        assert!(state.running.load(Ordering::Relaxed));
+    }
 }

src/server_pro/quota.rs

@@ -371,18 +371,92 @@ impl QuotaManager {
             tracing::error!("Failed to record user usage for {}: {}", username, e);
         }
 
-        // Record combined IP usage.
+        // Record IP usage — record_ip_usage already writes both the
+        // inbound_bytes and outbound_bytes columns in one operation.
+        // Do NOT also call record_ip_inbound_usage/record_ip_outbound_usage
+        // as they update the same columns and would double-count.
         if let Err(e) = self.db.record_ip_usage(ip, outbound_bytes, inbound_bytes) {
             tracing::error!("Failed to record IP usage for {}: {}", ip, e);
         }
+    }
 
-        // Record directional IP usage for the new per-direction columns.
-        if let Err(e) = self.db.record_ip_inbound_usage(ip, inbound_bytes) {
-            tracing::error!("Failed to record IP inbound usage for {}: {}", ip, e);
+    /// Calculate the remaining byte budget for a user+IP combination.
+    /// Returns the minimum remaining quota across all applicable limits.
+    /// Used to set `BandwidthState::byte_budget` before a test starts,
+    /// preventing overshoot beyond quota boundaries.
+    pub fn remaining_budget(&self, username: &str, ip: &IpAddr) -> u64 {
+        let mut budget = u64::MAX;
+        let ip_str = ip.to_string();
+
+        // Helper: min that ignores 0 (unlimited)
+        let cap = |budget: &mut u64, limit: u64, used: u64| {
+            if limit > 0 {
+                let remaining = limit.saturating_sub(used);
+                *budget = (*budget).min(remaining);
+            }
+        };
+
+        // User quotas (combined tx+rx)
+        if let Ok(Some(user)) = self.db.get_user(username) {
+            let daily_limit = if user.daily_quota > 0 { user.daily_quota as u64 } else { self.default_daily };
+            if daily_limit > 0 {
+                let (tx, rx) = self.db.get_daily_usage(username).unwrap_or((0, 0));
+                cap(&mut budget, daily_limit, tx + rx);
+            }
+
+            let weekly_limit = if user.weekly_quota > 0 { user.weekly_quota as u64 } else { self.default_weekly };
+            if weekly_limit > 0 {
+                let (tx, rx) = self.db.get_weekly_usage(username).unwrap_or((0, 0));
+                cap(&mut budget, weekly_limit, tx + rx);
+            }
+
+            if self.default_monthly > 0 {
+                let (tx, rx) = self.db.get_monthly_usage(username).unwrap_or((0, 0));
+                cap(&mut budget, self.default_monthly, tx + rx);
+            }
         }
-        if let Err(e) = self.db.record_ip_outbound_usage(ip, outbound_bytes) {
-            tracing::error!("Failed to record IP outbound usage for {}: {}", ip, e);
+
+        // IP combined quotas
+        if self.ip_daily > 0 {
+            let (tx, rx) = self.db.get_ip_daily_usage(&ip_str).unwrap_or((0, 0));
+            cap(&mut budget, self.ip_daily, tx + rx);
         }
+        if self.ip_weekly > 0 {
+            let (tx, rx) = self.db.get_ip_weekly_usage(&ip_str).unwrap_or((0, 0));
+            cap(&mut budget, self.ip_weekly, tx + rx);
+        }
+        if self.ip_monthly > 0 {
+            let (tx, rx) = self.db.get_ip_monthly_usage(&ip_str).unwrap_or((0, 0));
+            cap(&mut budget, self.ip_monthly, tx + rx);
+        }
+
+        // IP directional quotas — use inbound + outbound as combined ceiling
+        if self.ip_daily_inbound > 0 {
+            let used = self.db.get_ip_daily_inbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_daily_inbound, used);
+        }
+        if self.ip_daily_outbound > 0 {
+            let used = self.db.get_ip_daily_outbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_daily_outbound, used);
+        }
+        if self.ip_weekly_inbound > 0 {
+            let used = self.db.get_ip_weekly_inbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_weekly_inbound, used);
+        }
+        if self.ip_weekly_outbound > 0 {
+            let used = self.db.get_ip_weekly_outbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_weekly_outbound, used);
+        }
+        if self.ip_monthly_inbound > 0 {
+            let used = self.db.get_ip_monthly_inbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_monthly_inbound, used);
+        }
+        if self.ip_monthly_outbound > 0 {
+            let used = self.db.get_ip_monthly_outbound(&ip_str).unwrap_or(0);
+            cap(&mut budget, self.ip_monthly_outbound, used);
+        }
+
+        budget
     }
 
     pub fn max_duration(&self) -> u64 {

src/server_pro/server_loop.rs

@@ -2,14 +2,18 @@
 //!
 //! Wraps the standard btest server connection handler with:
 //! - Pre-connection IP/user quota checks
+//! - MD5 challenge-response auth against user DB
+//! - TCP multi-connection session support
 //! - Mid-session quota enforcement via QuotaEnforcer
 //! - Post-session usage recording
 
+use std::collections::HashMap;
 use std::net::SocketAddr;
 use std::sync::Arc;
 
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};
+use tokio::sync::Mutex;
 
 use btest_rs::protocol::*;
 use btest_rs::bandwidth::BandwidthState;
@@ -18,22 +22,27 @@ use super::enforcer::{QuotaEnforcer, StopReason};
 use super::quota::{Direction, QuotaManager};
 use super::user_db::UserDb;
 
+/// Pending TCP multi-connection session.
+struct TcpSession {
+    peer_ip: std::net::IpAddr,
+    username: String,
+    cmd: Command,
+    streams: Vec<TcpStream>,
+    expected: u8,
+}
+
+type SessionMap = Arc<Mutex<HashMap<u16, TcpSession>>>;
+
 /// Run the pro server with quota enforcement.
 pub async fn run_pro_server(
     port: u16,
-    ecsrp5: bool,
+    _ecsrp5: bool,
     listen_v4: Option<String>,
     listen_v6: Option<String>,
     db: UserDb,
     quota_mgr: QuotaManager,
     quota_check_interval: u64,
 ) -> anyhow::Result<()> {
-    // Pre-derive EC-SRP5 creds if needed
-    // For pro server, we don't use CLI -a/-p — we use the user DB
-    // EC-SRP5 needs a fixed password for the server challenge, but
-    // the actual verification happens against the DB.
-    // For now, the first user in the DB is used for EC-SRP5 derivation.
-
     let v4_listener = if let Some(ref addr) = listen_v4 {
         let bind_addr = format!("{}:{}", addr, port);
         Some(TcpListener::bind(&bind_addr).await?)
@@ -52,6 +61,8 @@ pub async fn run_pro_server(
         anyhow::bail!("No listeners bound");
     }
 
+    let sessions: SessionMap = Arc::new(Mutex::new(HashMap::new()));
+
     tracing::info!("btest-server-pro ready, accepting connections");
 
     loop {
@@ -69,29 +80,14 @@ pub async fn run_pro_server(
 
         tracing::info!("New connection from {}", peer);
 
-        // Pre-connection IP check
-        if let Err(e) = quota_mgr.check_ip(&peer.ip(), Direction::Both) {
-            tracing::warn!("Rejected {} — {}", peer, e);
-            btest_rs::syslog_logger::auth_failure(
-                &peer.to_string(), "-", "-", &format!("{}", e),
-            );
-            // Send a quick rejection and close
-            let mut s = stream;
-            let _ = s.write_all(&HELLO).await;
-            drop(s);
-            continue;
-        }
-
-        quota_mgr.connect(&peer.ip());
-
         let db = db.clone();
         let qm = quota_mgr.clone();
-        let qm_disconnect = quota_mgr.clone();
         let interval = quota_check_interval;
+        let sess = sessions.clone();
 
         tokio::spawn(async move {
-            match handle_pro_client(stream, peer, db, qm, interval).await {
-                Ok((username, stop_reason, tx, rx)) => {
+            let is_primary = match handle_pro_connection(stream, peer, db, qm.clone(), interval, sess).await {
+                Ok(Some((username, stop_reason, tx, rx))) => {
                     tracing::info!(
                         "Client {} (user '{}') finished: {} (tx={}, rx={})",
                         peer, username, stop_reason, tx, rx,
@@ -100,31 +96,100 @@ pub async fn run_pro_server(
                         &peer.to_string(), "btest", &format!("{}", stop_reason),
                         tx, rx, 0, 0,
                     );
+                    true
                 }
+                Ok(None) => false, // secondary connection or pending multi-conn
                 Err(e) => {
                     tracing::error!("Client {} error: {}", peer, e);
+                    true
                 }
+            };
+            // Only decrement connection count for primary connections
+            if is_primary {
+                qm.disconnect(&peer.ip());
             }
-            qm_disconnect.disconnect(&peer.ip());
         });
     }
 }
 
-async fn handle_pro_client(
+/// Handle a single TCP connection. Returns None for secondary multi-conn joins.
+async fn handle_pro_connection(
     mut stream: TcpStream,
     peer: SocketAddr,
     db: UserDb,
     quota_mgr: QuotaManager,
     quota_check_interval: u64,
-) -> anyhow::Result<(String, StopReason, u64, u64)> {
+    sessions: SessionMap,
+) -> anyhow::Result<Option<(String, StopReason, u64, u64)>> {
     stream.set_nodelay(true)?;
 
     // HELLO
     stream.write_all(&HELLO).await?;
 
-    // Read command
+    // Read command (or session token for secondary connections)
     let mut cmd_buf = [0u8; 16];
     stream.read_exact(&mut cmd_buf).await?;
+
+    // Check if this is a secondary connection joining an existing TCP session
+    // Secondary connections send [HI, LO, ...] matching an existing session token
+    {
+        let potential_token = u16::from_be_bytes([cmd_buf[0], cmd_buf[1]]);
+        let mut map = sessions.lock().await;
+        if let Some(session) = map.get_mut(&potential_token) {
+            if session.peer_ip == peer.ip()
+                && session.streams.len() < session.expected as usize
+            {
+                tracing::info!(
+                    "Secondary connection from {} joining session (token={:04x}, {}/{})",
+                    peer, potential_token,
+                    session.streams.len() + 1, session.expected,
+                );
+
+                // Auth the secondary connection with same token response
+                let ok = [0x01, cmd_buf[0], cmd_buf[1], 0x00];
+                stream.write_all(&ok).await?;
+                stream.flush().await?;
+
+                session.streams.push(stream);
+
+                // If all connections have joined, start the test
+                if session.streams.len() >= session.expected as usize {
+                    let session = map.remove(&potential_token).unwrap();
+                    let db2 = db.clone();
+                    let qm2 = quota_mgr.clone();
+                    tokio::spawn(async move {
+                        match run_pro_multiconn_test(
+                            session.streams, session.cmd, peer,
+                            &session.username, db2, qm2, quota_check_interval,
+                        ).await {
+                            Ok((stop, tx, rx)) => {
+                                tracing::info!(
+                                    "Multi-conn {} (user '{}') finished: {} (tx={}, rx={})",
+                                    peer, session.username, stop, tx, rx,
+                                );
+                            }
+                            Err(e) => {
+                                tracing::error!("Multi-conn {} error: {}", peer, e);
+                            }
+                        }
+                    });
+                }
+
+                return Ok(None);
+            }
+        }
+    }
+
+    // Primary connection — check IP quota/connection limit now
+    if let Err(e) = quota_mgr.check_ip(&peer.ip(), Direction::Both) {
+        tracing::warn!("Rejected {} — {}", peer, e);
+        btest_rs::syslog_logger::auth_failure(
+            &peer.to_string(), "-", "-", &format!("{}", e),
+        );
+        return Ok(None);
+    }
+    quota_mgr.connect(&peer.ip());
+
     let cmd = Command::deserialize(&cmd_buf);
 
     tracing::info!(
@@ -136,14 +201,25 @@ async fn handle_pro_client(
         cmd.tx_size,
     );
 
-    // Authenticate — use MD5 auth with DB verification
-    // Send AUTH_REQUIRED
+    // Build auth OK response with session token for multi-connection
+    let is_tcp_multi = !cmd.is_udp() && cmd.tcp_conn_count > 0;
+    let session_token: u16 = if is_tcp_multi {
+        rand::random::<u16>() | 0x0101 // ensure both bytes non-zero
+    } else {
+        0
+    };
+    let ok_response: [u8; 4] = if is_tcp_multi {
+        [0x01, (session_token >> 8) as u8, (session_token & 0xFF) as u8, 0x00]
+    } else {
+        AUTH_OK
+    };
+
+    // Authenticate — MD5 challenge-response against DB
     stream.write_all(&AUTH_REQUIRED).await?;
     let challenge = btest_rs::auth::generate_challenge();
     stream.write_all(&challenge).await?;
     stream.flush().await?;
 
-    // Read response
     let mut response = [0u8; 48];
     stream.read_exact(&mut response).await?;
 
@@ -176,17 +252,21 @@ async fn handle_pro_client(
                 anyhow::bail!("User disabled");
             }
 
-            // Verify MD5 hash against stored password hash
-            // We need to compute the expected hash using the user's password
-            // But we only store SHA256(user:pass), not the raw password.
-            // For MD5 auth, we need the raw password to compute MD5(pass + challenge).
-            // This is a limitation — MD5 auth needs the raw password.
-            // For now, accept any authenticated user (the hash verification
-            // happens on the client side with MikroTik).
-            // TODO: Store password in a reversible form or use EC-SRP5 only.
+            // Verify MD5 hash against stored raw password
+            if let Ok(Some(raw_pass)) = db.get_password(&username) {
+                let expected_hash = btest_rs::auth::compute_auth_hash(&raw_pass, &challenge);
+                if received_hash != expected_hash {
+                    tracing::warn!("Auth failed: password mismatch for user '{}'", username);
+                    stream.write_all(&AUTH_FAILED).await?;
+                    btest_rs::syslog_logger::auth_failure(
+                        &peer.to_string(), &username, "md5", "password mismatch",
+                    );
+                    anyhow::bail!("Auth failed");
+                }
+            }
+            // If no raw password stored, accept (backwards compat with old DB entries)
 
-            // Send AUTH_OK
-            stream.write_all(&AUTH_OK).await?;
+            stream.write_all(&ok_response).await?;
             stream.flush().await?;
 
             tracing::info!("Auth successful for user '{}'", username);
@@ -202,79 +282,168 @@ async fn handle_pro_client(
         btest_rs::syslog_logger::auth_failure(
             &peer.to_string(), &username, "quota", &format!("{}", e),
         );
-        // Connection is already authenticated, just close it
-        return Ok((username, StopReason::UserDailyQuota, 0, 0));
+        return Ok(Some((username, StopReason::UserDailyQuota, 0, 0)));
     }
 
-    // Start session tracking
+    // TCP multi-connection: register session and wait for secondary connections
+    if is_tcp_multi {
+        tracing::info!(
+            "TCP multi-connection: waiting for {} connections (token={:04x})",
+            cmd.tcp_conn_count, session_token,
+        );
+        let mut map = sessions.lock().await;
+        map.insert(session_token, TcpSession {
+            peer_ip: peer.ip(),
+            username: username.clone(),
+            cmd: cmd.clone(),
+            streams: vec![stream],
+            expected: cmd.tcp_conn_count, // tcp_conn_count includes the primary
+        });
+        // The test will be started when all connections join (in the secondary handler above)
+        return Ok(None);
+    }
+
+    // Single-connection test
+    run_pro_single_test(stream, cmd, peer, &username, db, quota_mgr, quota_check_interval).await
+        .map(|(stop, tx, rx)| Some((username, stop, tx, rx)))
+}
+
+/// Run a single-connection bandwidth test with quota enforcement.
+async fn run_pro_single_test(
+    stream: TcpStream,
+    cmd: Command,
+    peer: SocketAddr,
+    username: &str,
+    db: UserDb,
+    quota_mgr: QuotaManager,
+    quota_check_interval: u64,
+) -> anyhow::Result<(StopReason, u64, u64)> {
     let proto_str = if cmd.is_udp() { "UDP" } else { "TCP" };
     let dir_str = match cmd.direction {
         CMD_DIR_RX => "RX", CMD_DIR_TX => "TX", _ => "BOTH"
     };
     let session_id = db.start_session(
-        &username, &peer.ip().to_string(), proto_str, dir_str,
+        username, &peer.ip().to_string(), proto_str, dir_str,
     )?;
 
     btest_rs::syslog_logger::test_start(
         &peer.to_string(), proto_str, dir_str, cmd.tcp_conn_count,
     );
 
-    // Create shared bandwidth state for the test
     let state = BandwidthState::new();
 
-    // Spawn quota enforcer
+    // Set byte budget
+    let budget = quota_mgr.remaining_budget(username, &peer.ip());
+    if budget < u64::MAX {
+        state.set_budget(budget);
+        tracing::info!("Byte budget for '{}' from {}: {} bytes", username, peer.ip(), budget);
+    }
+
     let enforcer = QuotaEnforcer::new(
         quota_mgr.clone(),
-        username.clone(),
+        username.to_string(),
         peer.ip(),
         state.clone(),
         quota_check_interval,
         quota_mgr.max_duration(),
     );
 
-    // Spawn quota enforcer — runs alongside the test
     let enforcer_state = state.clone();
     let enforcer_handle = tokio::spawn(async move {
         enforcer.run().await
     });
 
-    // Run the actual bandwidth test using the standard server handlers.
-    // The enforcer runs concurrently and will set state.running = false
-    // if any quota is exceeded, which gracefully stops the TX/RX loops.
     static UDP_PORT_OFFSET: std::sync::atomic::AtomicU16 = std::sync::atomic::AtomicU16::new(0);
 
+    let mut stream_mut = stream;
     let test_result = if cmd.is_udp() {
         let offset = UDP_PORT_OFFSET.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
         let udp_port = btest_rs::protocol::BTEST_UDP_PORT_START + offset;
         btest_rs::server::run_udp_test(
-            &mut stream, peer, &cmd, state.clone(), udp_port,
+            &mut stream_mut, peer, &cmd, state.clone(), udp_port,
         ).await
     } else {
-        btest_rs::server::run_tcp_test(stream, cmd.clone(), state.clone()).await
+        btest_rs::server::run_tcp_test(stream_mut, cmd.clone(), state.clone()).await
     };
 
-    // Test finished — stop the enforcer if still running
     enforcer_state.running.store(false, std::sync::atomic::Ordering::SeqCst);
     let stop_reason = enforcer_handle.await.unwrap_or(StopReason::ClientDisconnected);
 
-    // Determine final stop reason
     let final_reason = match &test_result {
         Ok(_) => {
             if stop_reason == StopReason::ClientDisconnected {
                 StopReason::ClientDisconnected
             } else {
-                stop_reason // quota or duration exceeded
+                stop_reason
             }
         }
         Err(_) => StopReason::ClientDisconnected,
     };
 
-    // Record final usage
     let (total_tx, total_rx, _, _) = state.summary();
-
-    // Flush to DB
-    quota_mgr.record_usage(&username, &peer.ip().to_string(), total_tx, total_rx);
+    quota_mgr.record_usage(username, &peer.ip().to_string(), total_tx, total_rx);
     db.end_session(session_id, total_tx, total_rx)?;
 
-    Ok((username, final_reason, total_tx, total_rx))
+    Ok((final_reason, total_tx, total_rx))
+}
+
+/// Run a TCP multi-connection test with all streams collected.
+/// Delegates to the standard multi-conn handler which correctly manages
+/// TX+status injection for bidirectional mode.
+async fn run_pro_multiconn_test(
+    streams: Vec<TcpStream>,
+    cmd: Command,
+    peer: SocketAddr,
+    username: &str,
+    db: UserDb,
+    quota_mgr: QuotaManager,
+    quota_check_interval: u64,
+) -> anyhow::Result<(StopReason, u64, u64)> {
+    let dir_str = match cmd.direction {
+        CMD_DIR_RX => "RX", CMD_DIR_TX => "TX", _ => "BOTH"
+    };
+    let session_id = db.start_session(
+        username, &peer.ip().to_string(), "TCP", dir_str,
+    )?;
+
+    tracing::info!(
+        "Starting TCP multi-conn test: {} streams, dir={}",
+        streams.len(), dir_str,
+    );
+
+    let state = BandwidthState::new();
+
+    let budget = quota_mgr.remaining_budget(username, &peer.ip());
+    if budget < u64::MAX {
+        state.set_budget(budget);
+    }
+
+    let enforcer = QuotaEnforcer::new(
+        quota_mgr.clone(),
+        username.to_string(),
+        peer.ip(),
+        state.clone(),
+        quota_check_interval,
+        quota_mgr.max_duration(),
+    );
+
+    let enforcer_state = state.clone();
+    let enforcer_handle = tokio::spawn(async move {
+        enforcer.run().await
+    });
+
+    // Use the standard multi-connection handler which correctly handles
+    // all direction modes (TX, RX, BOTH with status injection)
+    let _test_result = btest_rs::server::run_tcp_multiconn_test(
+        streams, cmd, state.clone(),
+    ).await;
+
+    enforcer_state.running.store(false, std::sync::atomic::Ordering::SeqCst);
+    let stop_reason = enforcer_handle.await.unwrap_or(StopReason::ClientDisconnected);
+
+    let (total_tx, total_rx, _, _) = state.summary();
+    quota_mgr.record_usage(username, &peer.ip().to_string(), total_tx, total_rx);
+    db.end_session(session_id, total_tx, total_rx)?;
+
+    Ok((stop_reason, total_tx, total_rx))
 }

src/server_pro/user_db.rs

@@ -8,6 +8,7 @@ use std::sync::{Arc, Mutex};
 #[derive(Clone)]
 pub struct UserDb {
     conn: Arc<Mutex<Connection>>,
+    path: Arc<String>,
 }
 
 #[derive(Debug, Clone)]
@@ -68,9 +69,15 @@ impl UserDb {
         conn.execute_batch("PRAGMA journal_mode=WAL; PRAGMA busy_timeout=5000;")?;
         Ok(Self {
             conn: Arc::new(Mutex::new(conn)),
+            path: Arc::new(path.to_string()),
         })
     }
 
+    /// Return the database file path.
+    pub fn path(&self) -> &str {
+        &self.path
+    }
+
     pub fn ensure_tables(&self) -> anyhow::Result<()> {
         let conn = self.conn.lock().unwrap();
         conn.execute_batch("
@@ -147,13 +154,26 @@ impl UserDb {
     pub fn add_user(&self, username: &str, password: &str) -> anyhow::Result<()> {
         let hash = hash_password(username, password);
         let conn = self.conn.lock().unwrap();
+        // Ensure password_raw column exists (migration for older databases)
+        let _ = conn.execute("ALTER TABLE users ADD COLUMN password_raw TEXT DEFAULT ''", []);
         conn.execute(
-            "INSERT OR REPLACE INTO users (username, password_hash) VALUES (?1, ?2)",
-            params![username, hash],
+            "INSERT OR REPLACE INTO users (username, password_hash, password_raw) VALUES (?1, ?2, ?3)",
+            params![username, hash, password],
         )?;
         Ok(())
     }
 
+    /// Get the raw password for MD5 challenge-response auth.
+    pub fn get_password(&self, username: &str) -> anyhow::Result<Option<String>> {
+        let conn = self.conn.lock().unwrap();
+        let result = conn.query_row(
+            "SELECT password_raw FROM users WHERE username = ?1 AND enabled = 1",
+            params![username],
+            |row| row.get::<_, String>(0),
+        ).optional()?;
+        Ok(result)
+    }
+
     pub fn get_user(&self, username: &str) -> anyhow::Result<Option<User>> {
         let conn = self.conn.lock().unwrap();
         let mut stmt = conn.prepare(

src/server_pro/web/mod.rs

@@ -76,7 +76,7 @@ const DEFAULT_DB_PATH: &str = "btest-users.db";
 /// the web module is optional and failure during startup should surface
 /// loudly rather than silently serving broken pages.
 pub fn create_router(db: UserDb) -> Router {
-    let db_path = std::env::var("BTEST_DB_PATH").unwrap_or_else(|_| DEFAULT_DB_PATH.to_string());
+    let db_path = db.path().to_string();
 
     let query_conn = Connection::open_with_flags(
         &db_path,
@@ -104,6 +104,8 @@ pub fn create_router(db: UserDb) -> Router {
         .route("/dashboard/{ip}", get(dashboard_page))
         .route("/api/ip/{ip}/sessions", get(api_sessions))
         .route("/api/ip/{ip}/stats", get(api_stats))
+        .route("/api/ip/{ip}/export", get(api_export))
+        .route("/api/ip/{ip}/quota", get(api_quota))
         .route("/api/session/{id}/intervals", get(api_intervals))
         .with_state(state)
 }
@@ -142,47 +144,87 @@ fn ensure_web_tables(db_path: &str) -> anyhow::Result<()> {
 <head>
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
-<title>btest-rs Public Bandwidth Test Server</title>
+<title>btest-rs — Free Public Bandwidth Test Server</title>
 <style>
   *{margin:0;padding:0;box-sizing:border-box}
-  body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:#0f1117;color:#e1e4e8;min-height:100vh;display:flex;flex-direction:column;align-items:center;justify-content:center}
-  .container{max-width:560px;width:90%;text-align:center;padding:2rem}
-  h1{font-size:2rem;margin-bottom:.5rem;color:#58a6ff}
-  .subtitle{color:#8b949e;margin-bottom:2rem;line-height:1.5}
-  .search-box{display:flex;gap:.5rem;margin-bottom:1.5rem}
+  body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:#0f1117;color:#e1e4e8;min-height:100vh;display:flex;flex-direction:column;align-items:center;padding:2rem 1rem}
+  .container{max-width:720px;width:100%;padding:1rem 0}
+  h1{font-size:2.2rem;margin-bottom:.25rem;color:#58a6ff;text-align:center}
+  .subtitle{color:#8b949e;margin-bottom:2.5rem;line-height:1.6;text-align:center;font-size:1.05rem}
+  .section{background:#161b22;border:1px solid #30363d;border-radius:8px;padding:1.5rem;margin-bottom:1.5rem;text-align:left;line-height:1.7;color:#c9d1d9}
+  .section h2{color:#e1e4e8;font-size:1.15rem;margin-bottom:.75rem}
+  .section h3{color:#e1e4e8;font-size:1rem;margin-bottom:.5rem;margin-top:1rem}
+  .section h3:first-child{margin-top:0}
+  .section p{margin-bottom:.5rem}
+  .section ul{margin:.5rem 0 .5rem 1.5rem;color:#8b949e}
+  .section li{margin-bottom:.35rem}
+  code{background:#0d1117;padding:.2rem .5rem;border-radius:4px;font-size:.85em;color:#58a6ff;word-break:break-all}
+  pre{background:#0d1117;border:1px solid #30363d;border-radius:6px;padding:1rem;overflow-x:auto;margin:.75rem 0;line-height:1.5}
+  pre code{padding:0;background:none;font-size:.85em}
+  .label-tag{display:inline-block;padding:.15rem .5rem;border-radius:4px;font-size:.75rem;font-weight:600;text-transform:uppercase;letter-spacing:.03em;margin-right:.5rem;vertical-align:middle}
+  .tag-tcp{background:rgba(63,185,80,0.15);color:#3fb950}
+  .tag-udp{background:rgba(210,153,34,0.15);color:#d29922}
+  .note{background:#1c1e26;border-left:3px solid #d29922;padding:.75rem 1rem;border-radius:0 6px 6px 0;margin:.75rem 0;font-size:.92rem;color:#8b949e}
+  .note strong{color:#d29922}
+  .search-section{text-align:center}
+  .search-section h2{text-align:center}
+  .search-box{display:flex;gap:.5rem;margin-bottom:1rem}
   .search-box input{flex:1;padding:.75rem 1rem;border:1px solid #30363d;border-radius:6px;background:#161b22;color:#e1e4e8;font-size:1rem;outline:none}
   .search-box input:focus{border-color:#58a6ff}
   .search-box input::placeholder{color:#484f58}
   .search-box button{padding:.75rem 1.5rem;background:#238636;color:#fff;border:none;border-radius:6px;font-size:1rem;cursor:pointer;white-space:nowrap}
   .search-box button:hover{background:#2ea043}
-  .info{background:#161b22;border:1px solid #30363d;border-radius:8px;padding:1.5rem;text-align:left;line-height:1.6;color:#8b949e}
-  .info h3{color:#e1e4e8;margin-bottom:.5rem}
-  .info code{background:#0d1117;padding:.15rem .4rem;border-radius:4px;font-size:.9em;color:#58a6ff}
-  .auto-link{margin-top:1rem;font-size:.9rem}
+  .auto-link{font-size:.9rem;color:#8b949e}
   .auto-link a{color:#58a6ff;text-decoration:none}
   .auto-link a:hover{text-decoration:underline}
-  .footer{margin-top:2rem;color:#484f58;font-size:.8rem}
+  .footer{margin-top:2rem;color:#484f58;font-size:.8rem;text-align:center}
+  .footer a{color:#58a6ff;text-decoration:none}
+  .footer a:hover{text-decoration:underline}
 </style>
 </head>
 <body>
 <div class="container">
   <h1>btest-rs</h1>
-  <p class="subtitle">Public MikroTik Bandwidth Test Server &mdash; view your test results and history.</p>
-  <form class="search-box" id="ip-form" onsubmit="return goToDashboard()">
-    <input type="text" id="ip-input" placeholder="Enter your IP address (e.g. 203.0.113.5)" autocomplete="off">
-    <button type="submit">View Results</button>
-  </form>
-  <div class="auto-link" id="auto-detect">Detecting your IP...</div>
-  <div class="info">
-    <h3>How it works</h3>
-    <p>Run a bandwidth test from your MikroTik router targeting this server.
-       After the test completes, enter your public IP above to see
-       throughput charts, session history, and aggregate statistics.</p>
-    <p style="margin-top:0.5rem">
-      Example: <code>/tool bandwidth-test address=this-server protocol=tcp direction=both</code>
-    </p>
+  <p class="subtitle">Free public MikroTik-compatible bandwidth test server.<br>Test your link speed from any RouterOS device &mdash; no registration required.</p>
+
+  <div class="section">
+    <h2>Quick Start</h2>
+    <p>Open a terminal on your MikroTik router and run one of the following commands:</p>
+    <h3><span class="label-tag tag-tcp">TCP</span> Recommended</h3>
+    <pre><code>/tool bandwidth-test address=104.225.217.60 user=btest password=btest protocol=tcp direction=both</code></pre>
+    <h3><span class="label-tag tag-udp">UDP</span></h3>
+    <pre><code>/tool bandwidth-test address=104.225.217.60 user=btest password=btest protocol=udp direction=both</code></pre>
   </div>
-  <div class="footer">Powered by btest-rs</div>
+
+  <div class="section">
+    <h2>Important Notes</h2>
+    <ul>
+      <li><strong style="color:#e1e4e8">Credentials:</strong> <code>user=btest</code> <code>password=btest</code></li>
+      <li><strong style="color:#e1e4e8">TCP is recommended</strong> for remote testing &mdash; it works reliably through any NAT or firewall</li>
+      <li><strong style="color:#e1e4e8">Per-IP daily quotas</strong> apply to keep the service fair for everyone</li>
+      <li><strong style="color:#e1e4e8">Maximum test duration:</strong> 120 seconds</li>
+      <li><strong style="color:#e1e4e8">Connection limit:</strong> 3 concurrent tests per IP</li>
+    </ul>
+    <div class="note">
+      <strong>UDP bidirectional may not work through NAT/firewall.</strong>
+      UDP <code>direction=both</code> requires the server to send packets to a pre-calculated client port, which NAT routers typically block. If you need UDP testing:<br>
+      &bull; Forward UDP ports 2001&ndash;2100 on your router, or<br>
+      &bull; Use <code>direction=send</code> or <code>direction=receive</code> (one-way works fine), or<br>
+      &bull; Test from a device with a public IP
+    </div>
+  </div>
+
+  <div class="section search-section">
+    <h2>Check Your Results</h2>
+    <p style="margin-bottom:1rem;color:#8b949e">After running a test, enter your public IP to view throughput charts, session history, and statistics.</p>
+    <form class="search-box" id="ip-form" onsubmit="return goToDashboard()">
+      <input type="text" id="ip-input" placeholder="Enter your IP address (e.g. 203.0.113.5)" autocomplete="off">
+      <button type="submit">View Results</button>
+    </form>
+    <div class="auto-link" id="auto-detect">Detecting your IP...</div>
+  </div>
+
+  <div class="footer">Powered by <a href="https://github.com/manawenuz/btest-rs">btest-rs</a> &mdash; open source MikroTik bandwidth test server</div>
 </div>
 <script>
 function goToDashboard(){var ip=document.getElementById('ip-input').value.trim();if(ip){window.location.href='/dashboard/'+encodeURIComponent(ip);}return false;}
@@ -214,6 +256,8 @@ struct IndexTemplate;
   .header h1{font-size:1.5rem;color:#58a6ff}
   .header .ip-label{font-size:1.1rem;color:#8b949e;font-family:monospace}
   .header .home-link{margin-left:auto}
+  .btn{display:inline-block;padding:.5rem 1rem;border-radius:6px;font-size:.85rem;font-weight:500;cursor:pointer;border:1px solid #30363d;text-decoration:none}
+  .btn-json{background:#161b22;color:#3fb950}.btn-json:hover{background:#1c2128;text-decoration:none}
   .stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:1rem;margin-bottom:1.5rem}
   .stat-card{background:#161b22;border:1px solid #30363d;border-radius:8px;padding:1rem}
   .stat-card .label{color:#8b949e;font-size:.8rem;text-transform:uppercase;letter-spacing:.05em}
@@ -231,12 +275,22 @@ struct IndexTemplate;
   .chart-placeholder{text-align:center;color:#484f58;padding:3rem 0}
   .footer{text-align:center;color:#484f58;font-size:.8rem;margin-top:2rem}
   .no-data{text-align:center;padding:3rem;color:#484f58}
+  .quota-section{background:#161b22;border:1px solid #30363d;border-radius:8px;padding:1.25rem;margin-bottom:1.5rem}
+  .quota-section h2{font-size:1rem;color:#8b949e;margin-bottom:1rem}
+  .quota-row{display:flex;align-items:center;gap:1rem;margin-bottom:.75rem}
+  .quota-row:last-child{margin-bottom:0}
+  .quota-label{min-width:70px;font-size:.85rem;color:#8b949e;text-transform:uppercase;letter-spacing:.04em}
+  .quota-bar-wrap{flex:1;background:#21262d;border-radius:4px;height:22px;position:relative;overflow:hidden}
+  .quota-bar{height:100%;border-radius:4px;transition:width .5s ease}
+  .quota-bar.low{background:#238636}.quota-bar.mid{background:#d29922}.quota-bar.high{background:#da3633}
+  .quota-text{min-width:180px;font-size:.85rem;color:#e1e4e8;text-align:right;font-family:monospace}
 </style>
 </head>
 <body>
 <div class="header">
   <h1>btest-rs</h1>
   <span class="ip-label">{{ ip }}</span>
+  <a class="btn btn-json" href="/api/ip/{{ ip }}/export" download>Export JSON</a>
   <span class="home-link"><a href="/">Home</a></span>
 </div>
 <div class="stats" id="stats-grid">
@@ -246,6 +300,12 @@ struct IndexTemplate;
   <div class="stat-card"><div class="label">Avg TX Mbps</div><div class="value" id="stat-avg-tx">&mdash;</div></div>
   <div class="stat-card"><div class="label">Avg RX Mbps</div><div class="value" id="stat-avg-rx">&mdash;</div></div>
 </div>
+<div class="quota-section" id="quota-section">
+  <h2>Quota Usage</h2>
+  <div class="quota-row"><span class="quota-label">Daily</span><div class="quota-bar-wrap"><div class="quota-bar low" id="bar-daily" style="width:0%"></div></div><span class="quota-text" id="text-daily">&mdash;</span></div>
+  <div class="quota-row"><span class="quota-label">Weekly</span><div class="quota-bar-wrap"><div class="quota-bar low" id="bar-weekly" style="width:0%"></div></div><span class="quota-text" id="text-weekly">&mdash;</span></div>
+  <div class="quota-row"><span class="quota-label">Monthly</span><div class="quota-bar-wrap"><div class="quota-bar low" id="bar-monthly" style="width:0%"></div></div><span class="quota-text" id="text-monthly">&mdash;</span></div>
+</div>
 <div class="chart-section">
   <h2 id="chart-title">Select a test below to view its throughput chart</h2>
   <div class="chart-container">
@@ -266,6 +326,19 @@ var currentIp="{{ ip }}";
 var throughputChart=null;
 function formatBytes(b){if(b===0)return'0 B';var u=['B','KB','MB','GB','TB'];var i=Math.floor(Math.log(b)/Math.log(1024));if(i>=u.length)i=u.length-1;return(b/Math.pow(1024,i)).toFixed(1)+' '+u[i];}
 function formatMbps(bps){return(bps*8/1e6).toFixed(2);}
+fetch('/api/ip/'+encodeURIComponent(currentIp)+'/quota').then(function(r){return r.json();}).then(function(q){
+  function upd(id,used,limit){
+    var pct=limit>0?Math.min(used/limit*100,100):0;
+    var bar=document.getElementById('bar-'+id);
+    var txt=document.getElementById('text-'+id);
+    bar.style.width=pct.toFixed(1)+'%';
+    bar.className='quota-bar '+(pct<50?'low':pct<80?'mid':'high');
+    txt.textContent=formatBytes(used)+' / '+formatBytes(limit)+' ('+pct.toFixed(1)+'%)';
+  }
+  upd('daily',q.daily_used,q.daily_limit);
+  upd('weekly',q.weekly_used,q.weekly_limit);
+  upd('monthly',q.monthly_used,q.monthly_limit);
+}).catch(function(){});
 function durationStr(s,e){if(!s||!e)return'--';var ms=new Date(e)-new Date(s);if(ms<0)return'--';var sec=Math.round(ms/1000);if(sec<60)return sec+'s';return Math.floor(sec/60)+'m '+(sec%60)+'s';}
 function durationSec(s,e){if(!s||!e)return 0;return Math.max((new Date(e)-new Date(s))/1000,0.001);}
 fetch('/api/ip/'+encodeURIComponent(currentIp)+'/stats').then(function(r){return r.json();}).then(function(d){
@@ -495,6 +568,198 @@ async fn api_stats(
     Ok(axum::Json(stats))
 }
 
+/// Quota usage for an IP — daily/weekly/monthly with limits.
+#[derive(Serialize)]
+struct QuotaUsageJson {
+    daily_used: i64,
+    daily_limit: i64,
+    weekly_used: i64,
+    weekly_limit: i64,
+    monthly_used: i64,
+    monthly_limit: i64,
+}
+
+/// `GET /api/ip/{ip}/quota` -- return current quota usage for the IP.
+async fn api_quota(
+    State(state): State<Arc<WebState>>,
+    Path(ip): Path<String>,
+) -> Result<axum::Json<QuotaUsageJson>, AppError> {
+    let conn = state.query_conn.lock().map_err(|e| anyhow::anyhow!("lock: {}", e))?;
+
+    let daily: i64 = conn.query_row(
+        "SELECT COALESCE(SUM(inbound_bytes + outbound_bytes), 0) FROM ip_usage WHERE ip = ?1 AND date = date('now')",
+        params![ip], |row| row.get(0),
+    ).unwrap_or(0);
+
+    let weekly: i64 = conn.query_row(
+        "SELECT COALESCE(SUM(inbound_bytes + outbound_bytes), 0) FROM ip_usage WHERE ip = ?1 AND date >= date('now', '-7 days')",
+        params![ip], |row| row.get(0),
+    ).unwrap_or(0);
+
+    let monthly: i64 = conn.query_row(
+        "SELECT COALESCE(SUM(inbound_bytes + outbound_bytes), 0) FROM ip_usage WHERE ip = ?1 AND date >= date('now', '-30 days')",
+        params![ip], |row| row.get(0),
+    ).unwrap_or(0);
+
+    // Limits: 2GB daily, 8GB weekly, 24GB monthly
+    Ok(axum::Json(QuotaUsageJson {
+        daily_used: daily,
+        daily_limit: 2_147_483_648,
+        weekly_used: weekly,
+        weekly_limit: 8_589_934_592,
+        monthly_used: monthly,
+        monthly_limit: 25_769_803_776,
+    }))
+}
+
+/// Full export of all data for an IP — stats + sessions with human-readable fields.
+#[derive(Serialize)]
+struct ExportJson {
+    ip: String,
+    exported_at: String,
+    stats: StatsJson,
+    quota: QuotaJson,
+    sessions: Vec<ExportSessionJson>,
+}
+
+#[derive(Serialize)]
+struct QuotaJson {
+    daily_used_bytes: i64,
+    daily_used_human: String,
+    daily_limit_bytes: String,
+}
+
+#[derive(Serialize)]
+struct ExportSessionJson {
+    id: i64,
+    started_at: Option<String>,
+    ended_at: Option<String>,
+    protocol: Option<String>,
+    direction: Option<String>,
+    tx_bytes: i64,
+    rx_bytes: i64,
+    tx_human: String,
+    rx_human: String,
+    duration_secs: f64,
+    avg_tx_mbps: f64,
+    avg_rx_mbps: f64,
+}
+
+fn human_bytes(b: i64) -> String {
+    let b = b as f64;
+    if b >= 1_073_741_824.0 {
+        format!("{:.2} GB", b / 1_073_741_824.0)
+    } else if b >= 1_048_576.0 {
+        format!("{:.1} MB", b / 1_048_576.0)
+    } else if b >= 1024.0 {
+        format!("{:.1} KB", b / 1024.0)
+    } else {
+        format!("{} B", b as i64)
+    }
+}
+
+/// `GET /api/ip/{ip}/export` -- return a comprehensive JSON export of all
+/// sessions, stats, and quota usage for an IP. Suitable for download/archival.
+async fn api_export(
+    State(state): State<Arc<WebState>>,
+    Path(ip): Path<String>,
+) -> Result<impl IntoResponse, AppError> {
+    let conn = state
+        .query_conn
+        .lock()
+        .map_err(|e| anyhow::anyhow!("lock: {}", e))?;
+
+    // Stats
+    let stats = conn.query_row(
+        "SELECT COUNT(*), COALESCE(SUM(tx_bytes),0), COALESCE(SUM(rx_bytes),0),
+                COALESCE(SUM(CASE WHEN ended_at IS NOT NULL AND started_at IS NOT NULL
+                    THEN (julianday(ended_at)-julianday(started_at))*86400.0 ELSE 0 END),0)
+         FROM sessions WHERE peer_ip = ?1",
+        params![ip],
+        |row| {
+            let n: i64 = row.get(0)?;
+            let tx: i64 = row.get(1)?;
+            let rx: i64 = row.get(2)?;
+            let secs: f64 = row.get(3)?;
+            Ok(StatsJson {
+                total_sessions: n,
+                total_tx_bytes: tx,
+                total_rx_bytes: rx,
+                avg_tx_mbps: if secs > 0.0 { tx as f64 * 8.0 / secs / 1e6 } else { 0.0 },
+                avg_rx_mbps: if secs > 0.0 { rx as f64 * 8.0 / secs / 1e6 } else { 0.0 },
+            })
+        },
+    )?;
+
+    // Quota
+    let daily_used: i64 = conn.query_row(
+        "SELECT COALESCE(SUM(inbound_bytes + outbound_bytes), 0) FROM ip_usage
+         WHERE ip = ?1 AND date = date('now')",
+        params![ip],
+        |row| row.get(0),
+    ).unwrap_or(0);
+
+    let quota = QuotaJson {
+        daily_used_bytes: daily_used,
+        daily_used_human: human_bytes(daily_used),
+        daily_limit_bytes: "see server config".to_string(),
+    };
+
+    // Sessions with computed fields (duration computed by SQLite)
+    let mut stmt = conn.prepare(
+        "SELECT id, started_at, ended_at, protocol, direction, tx_bytes, rx_bytes,
+                CASE WHEN ended_at IS NOT NULL AND started_at IS NOT NULL
+                     THEN (julianday(ended_at) - julianday(started_at)) * 86400.0
+                     ELSE 0 END AS dur_secs
+         FROM sessions WHERE peer_ip = ?1 ORDER BY started_at DESC LIMIT 100",
+    )?;
+    let sessions: Vec<ExportSessionJson> = stmt.query_map(params![ip], |row| {
+        let tx: i64 = row.get(5)?;
+        let rx: i64 = row.get(6)?;
+        let dur: f64 = row.get(7)?;
+        Ok(ExportSessionJson {
+            id: row.get(0)?,
+            started_at: row.get(1)?,
+            ended_at: row.get(2)?,
+            protocol: row.get(3)?,
+            direction: row.get(4)?,
+            tx_bytes: tx,
+            rx_bytes: rx,
+            tx_human: human_bytes(tx),
+            rx_human: human_bytes(rx),
+            duration_secs: dur,
+            avg_tx_mbps: if dur > 0.0 { tx as f64 * 8.0 / dur / 1e6 } else { 0.0 },
+            avg_rx_mbps: if dur > 0.0 { rx as f64 * 8.0 / dur / 1e6 } else { 0.0 },
+        })
+    })?.filter_map(Result::ok).collect();
+
+    let export = ExportJson {
+        ip: ip.clone(),
+        exported_at: {
+            // Simple UTC timestamp without chrono
+            use std::time::{SystemTime, UNIX_EPOCH};
+            let secs = SystemTime::now().duration_since(UNIX_EPOCH).unwrap_or_default().as_secs();
+            format!("{}", secs) // Unix timestamp — universally parseable
+        },
+        stats,
+        quota,
+        sessions,
+    };
+
+    let json_string = serde_json::to_string_pretty(&export)
+        .map_err(|e| anyhow::anyhow!("json serialize: {}", e))?;
+
+    Ok((
+        StatusCode::OK,
+        [
+            (axum::http::header::CONTENT_TYPE, "application/json".to_string()),
+            (axum::http::header::CONTENT_DISPOSITION,
+             format!("attachment; filename=\"btest-{}.json\"", ip)),
+        ],
+        json_string,
+    ))
+}
+
 /// `GET /api/session/{id}/intervals` -- return per-second throughput data
 /// for a session.
 ///