MycroftOS: Mimic a captive portal to auto start a browser on wifi connect.

buildroot-external/configs/rpi3_defconfig

@@ -239,6 +239,7 @@ BR2_PACKAGE_C_ARES=y
 BR2_PACKAGE_LIBCURL=y
 BR2_PACKAGE_CURL=y
 BR2_PACKAGE_LIBHTTPPARSER=y
+BR2_PACKAGE_LIBMICROHTTPD=y
 BR2_PACKAGE_LIBNDP=y
 BR2_PACKAGE_LIBTIRPC=y
 BR2_PACKAGE_NGHTTP2=y
@@ -251,10 +252,17 @@ BR2_PACKAGE_PCRE_32=y
 BR2_PACKAGE_PCRE2_16=y
 BR2_PACKAGE_PCRE2_32=y
 BR2_PACKAGE_AVAHI=y
+BR2_PACKAGE_AVAHI_DAEMON=y
+BR2_PACKAGE_AVAHI_LIBDNSSD_COMPATIBILITY=y
 BR2_PACKAGE_CRDA=y
+BR2_PACKAGE_DNSMASQ=y
+# BR2_PACKAGE_DNSMASQ_TFTP is not set
+# BR2_PACKAGE_DNSMASQ_DHCP is not set
 BR2_PACKAGE_IPTABLES=y
 BR2_PACKAGE_IW=y
+BR2_PACKAGE_NGINX=y
 BR2_PACKAGE_NTP=y
+# BR2_PACKAGE_NTP_NTPD is not set
 BR2_PACKAGE_NTP_NTPDATE=y
 BR2_PACKAGE_NTP_NTPTIME=y
 BR2_PACKAGE_OPENSSH=y

buildroot-external/package/wifi-ap/dnsmasq.service

@@ -0,0 +1,19 @@
+[Unit]
+Description=Small DNS server to resolve everything to the AP interface.
+BindsTo=sys-subsystem-net-devices-ap0.device
+After=sys-subsystem-net-devices-ap0.device
+Before=network.target
+Wants=network.target
+
+# check existence of configuration file
+ConditionPathExists= /etc/wpa_supplicant/wpa_supplicant-ap0.conf
+ConditionPathExists=!/etc/wpa_supplicant/wpa_supplicant-wlan0.conf
+
+[Service]
+ExecStart=/usr/sbin/dnsmasq -k --conf-file=/etc/dnsmasq.conf
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=sys-subsystem-net-devices-ap0.device

buildroot-external/package/wifi-ap/iptables.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Packet Filtering Framework
+Before=network-pre.target
+Wants=network-pre.target
+
+# check existence of configuration file
+ConditionPathExists= /etc/wpa_supplicant/wpa_supplicant-ap0.conf
+ConditionPathExists=!/etc/wpa_supplicant/wpa_supplicant-wlan0.conf
+
+[Service]
+Type=oneshot
+ExecStart=/sbin/iptables-restore /etc/iptables.rules
+ExecReload=/sbin/iptables-restore /etc/iptables.rules
+ExecStop=/usr/lib/systemd/scripts/iptables-flush
+RemainAfterExit=yes
+
+[Install]
+WantedBy=multi-user.target

buildroot-external/package/wifi-ap/nginx.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=A high performance web server and a reverse proxy server
+BindsTo=sys-subsystem-net-devices-ap0.device
+After=sys-subsystem-net-devices-ap0.device syslog.target network.target
+
+# check existence of configuration file
+ConditionPathExists= /etc/wpa_supplicant/wpa_supplicant-ap0.conf
+ConditionPathExists=!/etc/wpa_supplicant/wpa_supplicant-wlan0.conf
+
+[Service]
+Type=forking
+PIDFile=/var/run/nginx.pid
+ExecStartPre=/usr/bin/mkdir -p /var/log/nginx /var/tmp/nginx
+ExecStartPre=/usr/sbin/nginx -t -q -g 'pid /var/run/nginx.pid; daemon on; master_process on;'
+ExecStart=/usr/sbin/nginx -g 'pid /var/run/nginx.pid; daemon on; master_process on;'
+ExecReload=/usr/sbin/nginx -g 'pid /var/run/nginx.pid; daemon on; master_process on;' -s reload
+ExecStop=/usr/sbin/nginx -g 'pid /var/run/nginx.pid;' -s quit
+PrivateDevices=yes
+
+[Install]
+WantedBy=multi-user.target

buildroot-external/package/wifi-ap/wifi-ap.mk

@@ -22,6 +22,10 @@ define WIFI_AP_INSTALL_TARGET_CMDS
                 $(TARGET_DIR)/usr/lib/systemd/system/wifi-setup.service
 	ln -fs ../../../../usr/lib/systemd/system/wifi-setup.service \
                 $(TARGET_DIR)/etc/systemd/system/sys-subsystem-net-devices-ap0.device.wants/wifi-setup.service
+	$(INSTALL) -D -m 644 $(@D)/dnsmasq.service \
+                $(TARGET_DIR)/usr/lib/systemd/system/dnsmasq.service
+        ln -fs ../../../../usr/lib/systemd/system/dnsmasq.service \
+                $(TARGET_DIR)/etc/systemd/system/sys-subsystem-net-devices-ap0.device.wants/dnsmasq.service
 
 	$(INSTALL) -D -m 644 $(@D)/wireless-mode-ap.service \
 		$(TARGET_DIR)/usr/lib/systemd/system/wireless-mode-ap.service
@@ -34,6 +38,18 @@ define WIFI_AP_INSTALL_TARGET_CMDS
         mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
         ln -fs ../../../../usr/lib/systemd/system/wireless-mode-client.service \
                 $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/wireless-mode-client.service
+
+	$(INSTALL) -D -m 644 $(@D)/nginx.service \
+                $(TARGET_DIR)/usr/lib/systemd/system/nginx.service
+        mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
+        ln -fs ../../../../usr/lib/systemd/system/nginx.service \
+                $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/nginx.service
+
+	$(INSTALL) -D -m 644 $(@D)/iptables.service \
+                $(TARGET_DIR)/usr/lib/systemd/system/iptables.service
+        mkdir -p $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants
+        ln -fs ../../../../usr/lib/systemd/system/iptables.service \
+                $(TARGET_DIR)/etc/systemd/system/multi-user.target.wants/iptables.service
 endef
 
 $(eval $(generic-package))

buildroot-external/rootfs-overlay/etc/dnsmasq.conf

@@ -0,0 +1,2 @@
+interface=ap0
+address=/#/172.16.127.1

buildroot-external/rootfs-overlay/etc/iptables.rules

@@ -0,0 +1,13 @@
+*nat
+:PREROUTING ACCEPT [14:1672]
+:INPUT ACCEPT [13:1640]
+:OUTPUT ACCEPT [24:1440]
+:POSTROUTING ACCEPT [24:1440]
+-A PREROUTING -p tcp -m tcp --dport 80 -j DNAT --to-destination 172.16.127.1
+-A PREROUTING -p tcp -m tcp --dport 443 -j DNAT --to-destination 172.16.127.1
+COMMIT
+*filter
+:INPUT ACCEPT [60540:12954317]
+:FORWARD ACCEPT [0:0]
+:OUTPUT ACCEPT [56210:7390098]
+COMMIT

buildroot-external/rootfs-overlay/etc/nginx/nginx.conf

@@ -0,0 +1,28 @@
+
+worker_processes  1;
+
+events {
+        worker_connections  1024;
+}
+
+http {
+    include       mime.types;
+    default_type  application/octet-stream;
+    sendfile        on;
+    keepalive_timeout  65;
+
+    server {
+        listen       80;
+        server_name  MycroftOS;
+        root         /opt/mycroft/wifisetup/templates;
+
+        # For iOS
+        if ($http_user_agent ~* (CaptiveNetworkSupport) ) {
+                return 302 http://172.16.127.1:88/hotspot.html;
+        }
+        # For others
+        location / {
+                return 302 http://172.16.127.1:88/;
+        }
+    }
+}

buildroot-external/rootfs-overlay/etc/systemd/network/wifi.network.ap

@@ -3,3 +3,5 @@ Name=ap0
 [Network]
 Address=172.16.127.1/28
 DHCPServer=yes
+[DHCPServer]
+DNS=172.16.127.1

buildroot-external/rootfs-overlay/etc/systemd/resolved.conf

@@ -0,0 +1,24 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+#
+# Entries in this file show the compile time defaults.
+# You can change settings by editing this file.
+# Defaults can be restored by simply deleting this file.
+#
+# See resolved.conf(5) for details
+
+[Resolve]
+#DNS=
+#FallbackDNS=8.8.8.8 8.8.4.4 2001:4860:4860::8888 2001:4860:4860::8844
+#Domains=
+#LLMNR=yes
+#MulticastDNS=yes
+#DNSSEC=no
+#DNSOverTLS=no
+#Cache=yes
+DNSStubListener=no
+#ReadEtcHosts=yes

buildroot-external/rootfs-overlay/opt/mycroft/wifisetup/templates/hotspot.html

@@ -0,0 +1,15 @@
+<!--
+<?xml version="1.0" encoding="UTF-8"?>
+<WISPAccessGatewayParam xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.wballiance.net/wispr_2_0.xsd">
+<Redirect>
+<MessageType>100</MessageType>
+<ResponseCode>0</ResponseCode>
+<VersionHigh>2.0</VersionHigh>
+<VersionLow>1.0</VersionLow>
+<AccessProcedure>1.0</AccessProcedure>
+<AccessLocation>MycroftOS-WiFiSetup Configuration</AccessLocation>
+<LocationName>MycroftOS-WiFiSetup</LocationName>
+<LoginURL>http://172.16.127.1:88/</LoginURL>
+</Redirect>
+</WISPAccessGatewayParam>
+-->

buildroot-external/rootfs-overlay/usr/lib/systemd/scripts/iptables-flush

@@ -0,0 +1,18 @@
+#!/bin/bash
+#
+# Usage: iptables-flush [6]
+#
+
+iptables=ip$1tables
+if ! type -p "$iptables"; then
+  echo "error: invalid argument"
+  exit 1
+fi
+
+while read -r table; do
+  tables+=("/var/lib/$iptables/empty-$table.rules")
+done <"/proc/net/ip$1_tables_names"
+
+if (( ${#tables[*]} )); then
+  cat "${tables[@]}" | "$iptables-restore"
+fi