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make PortalProxy domain-independent #7

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97e9eba
make PortalProxy respect X-Real-IP
binarynoise Jan 22, 2026
8c64342
make PortalProxy domain-independent
binarynoise Jan 23, 2026
a3a4840
separate PortalProxy proxy and portal onto different ports
programminghoch10 Jan 29, 2026
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69 changes: 69 additions & 0 deletions portalProxy/src/main/kotlin/IpUtils.kt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,69 @@
package de.binarynoise.captiveportalautologin.portalproxy.portal
import java.net.Inet4Address
import java.net.Inet6Address
import java.net.InetAddress
import java.net.UnknownHostException
import io.vertx.core.http.HttpServerRequest

fun HttpServerRequest.getRealRemoteIP(): String {
val ip = remoteAddress().host()

val headers = headers()
if (isLanIp(ip) && "X-Real-IP" in headers) {
val realIp = headers["X-Real-IP"]
if (realIp != null) return realIp.split(",").first().trim()
}
return ip
}

fun isLanIp(ipString: String): Boolean {
val addr = parseIp(ipString) ?: return false

return when (addr) {
is Inet4Address -> isPrivateIPv4(addr)
is Inet6Address -> isLocalIPv6(addr)
else -> false
}
}

fun parseIp(ipString: String): InetAddress? = try {
InetAddress.getByName(ipString.trim())
} catch (_: UnknownHostException) {
null
} catch (_: SecurityException) {
null
}


val loopbackV6 = ByteArray(16) { if (it == 15) 1 else 0 }
fun isLocalIPv6(addr: Inet6Address): Boolean {
val bytes = addr.address
val b0 = bytes[0].toInt()
val b1 = bytes[1].toInt()

// fc00::/7 (1111 110x)
val isUniqueLocal = (b0 and 0xFE) == 0xFC
// fe80::/10 (1111 1110 10xx xxxx)
val isLinkLocal = (b0 == 0xFE) && ((b1 and 0xC0) == 0x80)
val isLoopback = bytes.contentEquals(loopbackV6)

return isUniqueLocal || isLinkLocal || isLoopback
}

fun isPrivateIPv4(addr: Inet4Address): Boolean {
val bytes = addr.address
val b0 = bytes[0].toInt() and 0xFF
val b1 = bytes[1].toInt() and 0xFF

return when (b0) {
// 10.0.0.0/8
10 -> true
// 127.0.0.1/8
127 -> true
// 172.16.0.0/12
172 if (b1 in 16..31) -> true
// 192.168.0.0/16
192 if b1 == 168 -> true
else -> false
}
}
36 changes: 26 additions & 10 deletions portalProxy/src/main/kotlin/Main.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -2,10 +2,11 @@ package de.binarynoise.captiveportalautologin.portalproxy

import kotlin.coroutines.EmptyCoroutineContext
import kotlinx.coroutines.launch
import de.binarynoise.captiveportalautologin.portalproxy.portal.portalHost
import de.binarynoise.captiveportalautologin.portalproxy.portal.portalPort
import de.binarynoise.captiveportalautologin.portalproxy.portal.portalRouter
import de.binarynoise.captiveportalautologin.portalproxy.proxy.forward
import de.binarynoise.captiveportalautologin.portalproxy.proxy.forwardConnect
import de.binarynoise.captiveportalautologin.portalproxy.proxy.proxyPort
import de.binarynoise.logger.Logger
import de.binarynoise.logger.Logger.log
import io.vertx.core.Vertx
Expand All @@ -18,21 +19,22 @@ import io.vertx.kotlin.coroutines.dispatcher

class MainVerticle : CoroutineVerticle() {
override suspend fun start() {
val router = Router.router(vertx)

// Portal routes
router.route().virtualHost(portalHost).handler { ctx ->
val portalRouter = Router.router(vertx)
portalRouter.route().handler { ctx ->
log("route portal")
ctx.next()
}.subRouter(portalRouter(vertx))

// Proxy routes
router.route().handler { ctx ->
val proxyRouter = Router.router(vertx)
proxyRouter.route().handler { ctx ->
log("route /http")
forward(ctx.request())
}

val requestHandler: (HttpServerRequest) -> Unit = { request ->
val proxyRequestHandler: (HttpServerRequest) -> Unit = { request ->
launch(vertx.dispatcher() + EmptyCoroutineContext) {
log(buildString {
append("< ")
Expand All @@ -56,7 +58,7 @@ class MainVerticle : CoroutineVerticle() {
if (request.method() == HttpMethod.CONNECT) {
forwardConnect(request, vertx)
} else {
router.handle(request)
proxyRouter.handle(request)
}

log(buildString {
Expand All @@ -71,20 +73,34 @@ class MainVerticle : CoroutineVerticle() {
}
}

val portalRequestHandler: (HttpServerRequest) -> Unit = { request ->
launch(vertx.dispatcher() + EmptyCoroutineContext) {
portalRouter.handle(request)
}
}

val exceptionHandler = { t: Throwable ->
log("Unhandled exception during connection", t)
}
val invalidRequestHandler = { r: HttpServerRequest ->
log("Invalid request: $r")
}

val server = vertx.createHttpServer()
.requestHandler(requestHandler)
val proxyServer = vertx.createHttpServer()
.requestHandler(proxyRequestHandler)
.exceptionHandler(exceptionHandler)
.invalidRequestHandler(invalidRequestHandler)
.listen(proxyPort, "::")
.coAwait()
log("Started proxy server on port " + proxyServer.actualPort())

val portalServer = vertx.createHttpServer()
.requestHandler(portalRequestHandler)
.exceptionHandler(exceptionHandler)
.invalidRequestHandler(invalidRequestHandler)
.listen(8000, "::")
.listen(portalPort, "::")
.coAwait()
log("Started server on port " + server.actualPort())
log("Started portal server on port " + portalServer.actualPort())
}
}

Expand Down
28 changes: 20 additions & 8 deletions portalProxy/src/main/kotlin/Portal.kt
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
package de.binarynoise.captiveportalautologin.portalproxy.portal

import java.util.concurrent.ConcurrentHashMap
import java.util.concurrent.*
import kotlinx.coroutines.CoroutineScope
import kotlinx.html.*
import kotlinx.html.stream.*
Expand All @@ -10,8 +10,9 @@ import io.vertx.core.http.HttpServerRequest
import io.vertx.ext.web.Router
import io.vertx.kotlin.coroutines.coroutineRouter

const val portalHost = "binarynoise.de"
const val portalPort = 8000
const val portalPort = 8001
// TODO: use [System.getenv("PORTAL_HOST")] here
const val friendlyHost = "portal.binarynoise.de"

private val database = ConcurrentHashMap<String, Boolean>()

Expand All @@ -26,15 +27,17 @@ fun CoroutineScope.portalRouter(vertx: Vertx): Router {

// Login route
router.route("/login").handler { ctx ->
val ip = ctx.request().remoteAddress().host()
val ip = ctx.request().getRealRemoteIP()

database[ip] = false
log("logged in $ip")
ctx.response().putHeader("Location", "/").setStatusCode(302).end()
}

// Logout route
router.route("/logout").handler { ctx ->
val ip = ctx.request().remoteAddress().host()
val ip = ctx.request().getRealRemoteIP()

database[ip] = true
log("logged out $ip")
redirect(ctx.request())
Expand All @@ -49,12 +52,17 @@ fun CoroutineScope.portalRouter(vertx: Vertx): Router {
return router
}

fun getPortalHost(request: HttpServerRequest?) : String {
return request?.getHeader("Host") ?: friendlyHost
}

fun redirect(request: HttpServerRequest) {
request.response().putHeader("Location", "http://$portalHost:$portalPort/").setStatusCode(303).end()
val host = getPortalHost(request)
request.response().putHeader("Location", "http://$host:$portalPort/").setStatusCode(303).end()
}

fun checkCaptured(request: HttpServerRequest): Boolean {
val ip = request.remoteAddress().host()
val ip = request.getRealRemoteIP()
return database[ip] ?: true
}

Expand Down Expand Up @@ -89,6 +97,10 @@ private fun servePortalPage(request: HttpServerRequest) {
body {
h1 { +"Captive Portal" }
p { +"You are currently ${if (captured) "captured" else "not captured"}" }
p {
+"Your IP is "
code { +request.getRealRemoteIP() }
}

form("/login") {
p {
Expand All @@ -105,7 +117,7 @@ private fun servePortalPage(request: HttpServerRequest) {
p {
+"This page can be opened again at"
br()
val href = "http://$portalHost:$portalPort/"
val href = "http://${getPortalHost(request)}:$portalPort/"
a(href = href) { +href }
}
}
Expand Down
1 change: 1 addition & 0 deletions portalProxy/src/main/kotlin/Proxy.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@ import io.vertx.kotlin.coroutines.coAwait

private val allowlistDomain = listOf("am-i-captured.binarynoise.de", "www.google.com")
private val allowlistPort = listOf("80", "443")
val proxyPort = 8000

fun forward(request: HttpServerRequest) {
if (checkCaptured(request)) {
Expand Down
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