311 lines
9.8 KiB
Bash
Executable File
311 lines
9.8 KiB
Bash
Executable File
#!/bin/bash
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# =============================================================================
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# wifi-sim.sh — Virtual WiFi environment for development & testing
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#
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# Creates 3 dummy networks using mac80211_hwsim + hostapd:
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# - FreeWifi (open, strong signal, ch 1)
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# - OfficeNetwork (open, medium signal, ch 6)
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# - HomeNetwork (WPA2, weak signal, ch 11)
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#
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# Usage:
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# sudo ./wifi-sim.sh start
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# sudo ./wifi-sim.sh stop
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# sudo ./wifi-sim.sh status
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# =============================================================================
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set -euo pipefail
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# --- User configuration ------------------------------------------------------
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SSID_STRONG="FreeWifi" # Open network, strong signal
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SSID_MEDIUM="OfficeNetwork" # Open network, medium signal
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SSID_SECURE="HomeNetwork" # WPA2 network, weak signal
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WIFI_PASSWORD="testpassword123"
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# TX power levels in mBm (millibel-milliwatts). Higher = stronger signal.
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# These affect the RSSI reported to scanning clients.
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TXPOWER_STRONG=3000 # 30 dBm
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TXPOWER_MEDIUM=1500 # 15 dBm
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TXPOWER_WEAK=100 # 1 dBm
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RUN_DIR="/tmp/wifi-sim"
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# --- Helpers -----------------------------------------------------------------
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die() {
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echo "ERROR: $*" >&2
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exit 1
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}
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info() { echo "[*] $*"; }
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ok() { echo "[+] $*"; }
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require_cmds() {
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local missing=()
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for cmd in "$@"; do
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command -v "$cmd" &>/dev/null || missing+=("$cmd")
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done
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if [[ ${#missing[@]} -gt 0 ]]; then
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die "Missing required tools: ${missing[*]}
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Install with: sudo apt install hostapd wpasupplicant iw"
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fi
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}
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get_phy_for_iface() {
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iw dev "$1" info | awk '/wiphy/{print "phy"$2}'
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}
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# --- Start -------------------------------------------------------------------
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cmd_start() {
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[[ $EUID -ne 0 ]] && die "Please run as root: sudo $0 start"
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require_cmds hostapd iw ip
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if [[ -d "$RUN_DIR" && -f "$RUN_DIR/interfaces" ]]; then
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die "wifi-sim appears to already be running. Run 'sudo $0 stop' first."
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fi
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mkdir -p "$RUN_DIR"
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# Snapshot existing wlan interfaces so we can identify the new ones
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info "Snapshotting existing interfaces..."
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BEFORE=($(iw dev 2>/dev/null | awk '/Interface/{print $2}' | grep -v '^hwsim' || true))
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# Load the kernel module with 4 radios (3 APs + 1 client)
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info "Loading mac80211_hwsim (4 radios)..."
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if lsmod | grep -q mac80211_hwsim; then
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die "mac80211_hwsim is already loaded. Run 'sudo $0 stop' or 'sudo rmmod mac80211_hwsim' first."
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fi
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modprobe mac80211_hwsim radios=4
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sleep 1 # Give the kernel a moment to register all interfaces
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# Find the interfaces created by our modprobe
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AFTER=($(iw dev 2>/dev/null | awk '/Interface/{print $2}' | grep -v '^hwsim'))
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NEW_IFACES=()
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for iface in "${AFTER[@]}"; do
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[[ ! " ${BEFORE[*]:-} " =~ " $iface " ]] && NEW_IFACES+=("$iface")
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done
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if [[ ${#NEW_IFACES[@]} -lt 4 ]]; then
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rmmod mac80211_hwsim 2>/dev/null || true
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die "Expected 4 new wlan interfaces, found ${#NEW_IFACES[@]}. Check 'dmesg' for errors."
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fi
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AP1="${NEW_IFACES[0]}" # Will host SSID_STRONG
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AP2="${NEW_IFACES[1]}" # Will host SSID_MEDIUM
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AP3="${NEW_IFACES[2]}" # Will host SSID_SECURE
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CLIENT="${NEW_IFACES[3]}" # Client-side interface for your code to use
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info "Interfaces assigned: AP1=$AP1 AP2=$AP2 AP3=$AP3 Client=$CLIENT"
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echo "$AP1 $AP2 $AP3 $CLIENT" >"$RUN_DIR/interfaces"
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# Prevent NetworkManager from fighting us over these interfaces
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if command -v nmcli &>/dev/null && nmcli general status &>/dev/null 2>&1; then
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info "Marking interfaces as unmanaged in NetworkManager..."
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for iface in "$AP1" "$AP2" "$AP3"; do
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nmcli device set "$iface" managed no 2>/dev/null || true
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done
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nmcli device set "$CLIENT" managed yes
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fi
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# Set TX power on each physical radio to simulate signal strength differences.
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# mac80211_hwsim factors TX power into the RSSI reported to scanning clients.
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# Note: for precise RSSI control, consider 'wmediumd' (a wireless medium daemon).
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info "Setting TX power levels for signal strength simulation..."
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PHY1=$(get_phy_for_iface "$AP1")
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PHY2=$(get_phy_for_iface "$AP2")
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PHY3=$(get_phy_for_iface "$AP3")
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iw phy "$PHY1" set txpower fixed $TXPOWER_STRONG
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iw phy "$PHY2" set txpower fixed $TXPOWER_MEDIUM
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iw phy "$PHY3" set txpower fixed $TXPOWER_WEAK
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# --- hostapd config: AP1 (open, strong, channel 1) -----------------------
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cat >"$RUN_DIR/ap1.conf" <<EOF
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interface=$AP1
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driver=nl80211
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ssid=$SSID_STRONG
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hw_mode=g
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channel=1
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auth_algs=1
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wmm_enabled=0
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ignore_broadcast_ssid=0
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EOF
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# --- hostapd config: AP2 (open, medium, channel 6) -----------------------
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cat >"$RUN_DIR/ap2.conf" <<EOF
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interface=$AP2
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driver=nl80211
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ssid=$SSID_MEDIUM
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hw_mode=g
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channel=6
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auth_algs=1
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wmm_enabled=0
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ignore_broadcast_ssid=0
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EOF
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# --- hostapd config: AP3 (WPA2, weak, channel 11) ------------------------
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cat >"$RUN_DIR/ap3.conf" <<EOF
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interface=$AP3
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driver=nl80211
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ssid=$SSID_SECURE
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hw_mode=g
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channel=11
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auth_algs=1
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wpa=2
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wpa_passphrase=$WIFI_PASSWORD
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wpa_key_mgmt=WPA-PSK
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rsn_pairwise=CCMP
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wmm_enabled=0
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ignore_broadcast_ssid=0
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EOF
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# Start a hostapd instance for each AP
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info "Starting hostapd instances..."
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hostapd -B -P "$RUN_DIR/ap1.pid" "$RUN_DIR/ap1.conf" \
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>"$RUN_DIR/ap1.log" 2>&1 ||
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{
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cat "$RUN_DIR/ap1.log"
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die "hostapd failed for AP1. See log above."
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}
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hostapd -B -P "$RUN_DIR/ap2.pid" "$RUN_DIR/ap2.conf" \
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>"$RUN_DIR/ap2.log" 2>&1 ||
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{
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cat "$RUN_DIR/ap2.log"
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die "hostapd failed for AP2. See log above."
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}
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hostapd -B -P "$RUN_DIR/ap3.pid" "$RUN_DIR/ap3.conf" \
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>"$RUN_DIR/ap3.log" 2>&1 ||
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{
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cat "$RUN_DIR/ap3.log"
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die "hostapd failed for AP3. See log above."
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}
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# Bring up the client interface so it's ready to scan/connect
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ip link set "$CLIENT" up
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# --- Summary -------------------------------------------------------------
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ok "Virtual WiFi environment is up!"
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echo ""
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echo " Networks:"
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echo " ┌──────────────────┬──────────┬────────┬─────────────┐"
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echo " │ SSID │ Security │ Signal │ Interface │"
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echo " ├──────────────────┼──────────┼────────┼─────────────┤"
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printf " │ %-16s │ %-8s │ %-6s │ %-11s │\n" "$SSID_STRONG" "Open" "Strong" "$AP1"
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printf " │ %-16s │ %-8s │ %-6s │ %-11s │\n" "$SSID_MEDIUM" "Open" "Medium" "$AP2"
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printf " │ %-16s │ %-8s │ %-6s │ %-11s │\n" "$SSID_SECURE" "WPA2" "Weak" "$AP3"
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echo " └──────────────────┴──────────┴────────┴─────────────┘"
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echo ""
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echo " WPA2 password : $WIFI_PASSWORD"
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echo " Client iface : $CLIENT (use this in your code)"
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echo ""
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echo " Useful commands:"
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echo " Scan for networks : sudo iw dev $CLIENT scan | grep -E 'SSID|signal'"
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echo " Connect (open) : sudo iw dev $CLIENT connect \"$SSID_STRONG\""
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echo " Connect (WPA2) : sudo wpa_supplicant -Dnl80211 -i$CLIENT \\"
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echo " -c <(wpa_passphrase \"$SSID_SECURE\" \"$WIFI_PASSWORD\")"
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echo " Stop simulation : sudo $0 stop"
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echo ""
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echo " Logs: $RUN_DIR/ap{1,2,3}.log"
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}
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# --- Stop --------------------------------------------------------------------
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cmd_stop() {
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[[ $EUID -ne 0 ]] && die "Please run as root: sudo $0 stop"
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info "Stopping virtual WiFi environment..."
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local had_something=false
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# Kill hostapd processes via PID files
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for ap in ap1 ap2 ap3; do
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PID_FILE="$RUN_DIR/$ap.pid"
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if [[ -f "$PID_FILE" ]]; then
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PID=$(cat "$PID_FILE")
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if kill "$PID" 2>/dev/null; then
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info "Stopped hostapd for $ap (PID $PID)"
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fi
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rm -f "$PID_FILE"
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had_something=true
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fi
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done
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# Re-enable NetworkManager management for these interfaces
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if [[ -f "$RUN_DIR/interfaces" ]]; then
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read -r AP1 AP2 AP3 CLIENT <"$RUN_DIR/interfaces"
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if command -v nmcli &>/dev/null; then
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for iface in "$AP1" "$AP2" "$AP3" "$CLIENT"; do
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nmcli device set "$iface" managed yes 2>/dev/null || true
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done
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fi
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fi
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# Unload the kernel module (also destroys all virtual interfaces)
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if lsmod | grep -q mac80211_hwsim; then
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info "Unloading mac80211_hwsim..."
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rmmod mac80211_hwsim && had_something=true
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fi
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# Clean up runtime directory
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rm -rf "$RUN_DIR"
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if $had_something; then
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ok "Virtual WiFi environment stopped."
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else
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echo "Nothing was running."
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fi
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}
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# --- Status ------------------------------------------------------------------
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cmd_status() {
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if [[ ! -f "$RUN_DIR/interfaces" ]]; then
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echo "wifi-sim is not running."
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return
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fi
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read -r AP1 AP2 AP3 CLIENT <"$RUN_DIR/interfaces"
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echo "wifi-sim is running."
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echo ""
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echo " Interfaces:"
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for iface in "$AP1" "$AP2" "$AP3" "$CLIENT"; do
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STATE=$(ip link show "$iface" 2>/dev/null | awk '/state/{print $9}' || echo "unknown")
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CHANNEL=$(iw dev "$iface" info 2>/dev/null | awk '/channel/{print $2}' || echo "?")
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printf " %-10s state=%-4s channel=%s\n" "$iface" "$STATE" "$CHANNEL"
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done
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echo ""
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echo " Processes:"
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for ap in ap1 ap2 ap3; do
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PID_FILE="$RUN_DIR/$ap.pid"
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if [[ -f "$PID_FILE" ]]; then
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PID=$(cat "$PID_FILE")
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if kill -0 "$PID" 2>/dev/null; then
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echo " hostapd ($ap) PID=$PID running"
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else
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echo " hostapd ($ap) PID=$PID DEAD (check $RUN_DIR/$ap.log)"
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fi
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fi
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done
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}
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# --- Entry point -------------------------------------------------------------
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case "${1:-help}" in
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start) cmd_start ;;
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stop) cmd_stop ;;
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status) cmd_status ;;
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*)
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echo "Usage: sudo $0 {start|stop|status}"
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echo ""
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echo " start Load mac80211_hwsim and bring up 3 virtual APs"
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echo " stop Tear down all virtual interfaces and unload module"
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echo " status Show current state of interfaces and processes"
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echo ""
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echo "Networks created on start:"
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printf " %-16s open, strong signal\n" "$SSID_STRONG"
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printf " %-16s open, medium signal\n" "$SSID_MEDIUM"
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printf " %-16s WPA2, weak signal (password: $WIFI_PASSWORD)\n" "$SSID_SECURE"
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;;
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esac
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