Initial commit: MikroTik btest server & client in Rust

Full reimplementation of the MikroTik Bandwidth Test protocol:
- Server mode: accepts connections from MikroTik devices on port 2000
- Client mode: connects to MikroTik btest servers
- TCP and UDP protocols with bidirectional support
- MD5 challenge-response authentication
- Dynamic speed adjustment (1.5x algorithm)
- Status exchange matching original C pselect() behavior
- Docker support with multi-stage build

Tested against MikroTik RouterOS achieving:
- 1.05 Gbps server RX (single connection)
- 530 Mbps client TCP download
- 840 Mbps client TCP upload
- 433 Mbps client UDP download

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

scripts/test-docker.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# Test using Docker
+set -euo pipefail
+
+echo "=== Building Docker image ==="
+docker build -t btest .
+
+echo ""
+echo "=== Running btest server in Docker ==="
+docker run -d --name btest-test -p 2000:2000/tcp -p 2001-2100:2001-2100/udp -p 2257-2356:2257-2356/udp btest -s -v
+sleep 2
+
+cleanup() {
+    echo "Stopping Docker container..."
+    docker stop btest-test 2>/dev/null || true
+    docker rm btest-test 2>/dev/null || true
+}
+trap cleanup EXIT
+
+BTEST="./target/release/btest"
+cargo build --release
+
+run_timed() {
+    local desc="$1"; shift
+    echo ""
+    echo "--- $desc ---"
+    $BTEST "$@" &
+    local pid=$!
+    sleep 5
+    kill $pid 2>/dev/null || true
+    wait $pid 2>/dev/null || true
+}
+
+run_timed "TCP Download from Docker server" -c 127.0.0.1 -r
+run_timed "TCP Upload to Docker server" -c 127.0.0.1 -t
+run_timed "TCP Bidirectional" -c 127.0.0.1 -t -r
+
+echo ""
+echo "=== Docker server logs ==="
+docker logs btest-test
+
+echo ""
+echo "=== Docker tests completed ==="

scripts/test-local.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+# Local loopback tests - run server and client against each other
+set -euo pipefail
+
+BTEST="cargo run --release --"
+PORT=2000
+
+echo "=== Building release binary ==="
+cargo build --release
+
+BTEST="./target/release/btest"
+
+cleanup() {
+    echo "Stopping server..."
+    kill $SERVER_PID 2>/dev/null || true
+    wait $SERVER_PID 2>/dev/null || true
+}
+
+echo ""
+echo "=== Starting btest server on port $PORT ==="
+$BTEST -s -P $PORT -v &
+SERVER_PID=$!
+trap cleanup EXIT
+sleep 1
+
+TIMEOUT_CMD="timeout"
+if ! command -v timeout &>/dev/null; then
+    if command -v gtimeout &>/dev/null; then
+        TIMEOUT_CMD="gtimeout"
+    else
+        # Fallback: background + sleep + kill
+        TIMEOUT_CMD=""
+    fi
+fi
+
+run_test() {
+    local desc="$1"
+    shift
+    echo ""
+    echo "--- Test: $desc ---"
+    if [ -n "$TIMEOUT_CMD" ]; then
+        $TIMEOUT_CMD 5 $BTEST "$@" || true
+    else
+        $BTEST "$@" &
+        local pid=$!
+        sleep 5
+        kill $pid 2>/dev/null || true
+        wait $pid 2>/dev/null || true
+    fi
+    echo "--- Done: $desc ---"
+    sleep 1
+}
+
+run_test "TCP Download (RX)" -c 127.0.0.1 -P $PORT -r
+run_test "TCP Upload (TX)" -c 127.0.0.1 -P $PORT -t
+run_test "TCP Bidirectional" -c 127.0.0.1 -P $PORT -t -r
+run_test "TCP Download 100Mbps limited" -c 127.0.0.1 -P $PORT -r -b 100M
+run_test "UDP Download" -c 127.0.0.1 -P $PORT -r -u
+run_test "UDP Upload" -c 127.0.0.1 -P $PORT -t -u
+run_test "UDP Bidirectional" -c 127.0.0.1 -P $PORT -t -r -u
+
+echo ""
+echo "=== All local tests completed ==="

scripts/test-mikrotik.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+# Test against a MikroTik device
+# Usage: ./scripts/test-mikrotik.sh <mikrotik_ip> [username] [password]
+set -euo pipefail
+
+MIKROTIK_IP="${1:?Usage: $0 <mikrotik_ip> [username] [password]}"
+USERNAME="${2:-}"
+PASSWORD="${3:-}"
+BTEST="./target/release/btest"
+
+echo "=== Building release binary ==="
+cargo build --release
+
+AUTH_ARGS=""
+if [ -n "$USERNAME" ]; then
+    AUTH_ARGS="-a $USERNAME"
+fi
+if [ -n "$PASSWORD" ]; then
+    AUTH_ARGS="$AUTH_ARGS -p $PASSWORD"
+fi
+
+echo ""
+echo "=== Testing against MikroTik at $MIKROTIK_IP ==="
+echo ""
+
+TIMEOUT_CMD="timeout"
+if ! command -v timeout &>/dev/null; then
+    if command -v gtimeout &>/dev/null; then
+        TIMEOUT_CMD="gtimeout"
+    else
+        TIMEOUT_CMD=""
+    fi
+fi
+
+run_test() {
+    local desc="$1"
+    shift
+    echo "--- $desc ---"
+    if [ -n "$TIMEOUT_CMD" ]; then
+        $TIMEOUT_CMD 10 $BTEST "$@" $AUTH_ARGS || echo "(test ended)"
+    else
+        $BTEST "$@" $AUTH_ARGS &
+        local pid=$!
+        sleep 10
+        kill $pid 2>/dev/null || true
+        wait $pid 2>/dev/null || true
+        echo "(test ended)"
+    fi
+    echo ""
+    sleep 1
+}
+
+echo "=== Mode 1: Our client -> MikroTik btest server ==="
+echo "(Make sure btest server is enabled on your MikroTik: /tool/bandwidth-server set enabled=yes)"
+echo ""
+
+run_test "TCP Download from MikroTik" -c "$MIKROTIK_IP" -r
+run_test "TCP Upload to MikroTik" -c "$MIKROTIK_IP" -t
+run_test "TCP Bidirectional with MikroTik" -c "$MIKROTIK_IP" -t -r
+run_test "UDP Download from MikroTik" -c "$MIKROTIK_IP" -r -u
+run_test "UDP Upload to MikroTik" -c "$MIKROTIK_IP" -t -u
+
+echo ""
+echo "=== Mode 2: Our server <- MikroTik connects to us ==="
+echo "To test this mode:"
+echo "  1. Run:  $BTEST -s -v $AUTH_ARGS"
+echo "  2. On MikroTik, run:"
+echo "     /tool/bandwidth-test address=<this_server_ip> direction=both protocol=tcp"
+echo ""
+echo "=== All MikroTik tests completed ==="