From 05a81b89a1234d605df28ce8c7a4eebd29e8d1ff Mon Sep 17 00:00:00 2001
From: Dennis Luxen <info@project-osrm.org>
Date: Sun, 18 Feb 2024 21:02:47 +0100
Subject: [PATCH] Implement initial TLS support (#93)

---
 Cargo.toml                                  |  1 +
 hms2mqtt/src/mqtt_config.rs                 |  1 +
 src/bin/hms-mqtt-publish/rumqttc_wrapper.rs | 34 +++++++++++++++++++--
 tests/integration_tests.rs                  |  1 +
 4 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 636ac0f8..ad45e857 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ env_logger = "0.11.0"
 hms2mqtt = { path = "hms2mqtt" }
 log = "0.4.20"
 rumqttc = "0.23.0"
+rustls-native-certs = "0.7.0"
 serde = { version = "1.0.195", features = ["derive"] }
 serde_derive = "1.0.195"
 toml = "0.8.8"
diff --git a/hms2mqtt/src/mqtt_config.rs b/hms2mqtt/src/mqtt_config.rs
index 47f61ee6..5eccc097 100644
--- a/hms2mqtt/src/mqtt_config.rs
+++ b/hms2mqtt/src/mqtt_config.rs
@@ -6,4 +6,5 @@ pub struct MqttConfig {
     pub port: Option<u16>,
     pub username: Option<String>,
     pub password: Option<String>,
+    pub tls: Option<bool>,
 }
diff --git a/src/bin/hms-mqtt-publish/rumqttc_wrapper.rs b/src/bin/hms-mqtt-publish/rumqttc_wrapper.rs
index ea0df3f4..234448b6 100644
--- a/src/bin/hms-mqtt-publish/rumqttc_wrapper.rs
+++ b/src/bin/hms-mqtt-publish/rumqttc_wrapper.rs
@@ -5,7 +5,12 @@ use hms2mqtt::{
     mqtt_wrapper::{self},
 };
 use log::warn;
-use rumqttc::{Client, MqttOptions, QoS::AtMostOnce};
+use rumqttc::{
+    tokio_rustls::{self, rustls::ClientConfig},
+    Client, MqttOptions,
+    QoS::AtMostOnce,
+    Transport,
+};
 
 pub struct RumqttcWrapper {
     client: Client,
@@ -58,12 +63,37 @@ impl mqtt_wrapper::MqttWrapper for RumqttcWrapper {
     }
 
     fn new(config: &MqttConfig, suffix: &str) -> Self {
+        let use_tls = config.tls.is_some_and(|tls| tls);
+
         let mut mqttoptions = MqttOptions::new(
             "hms800wt2-mqtt-publisher".to_string() + suffix,
             &config.host,
-            config.port.unwrap_or(1883),
+            config.port.unwrap_or_else(|| {
+                if use_tls {
+                    return 8883;
+                }
+                1883
+            }),
         );
         mqttoptions.set_keep_alive(Duration::from_secs(5));
+        if use_tls {
+            // Use rustls-native-certs to load root certificates from the operating system.
+            let mut roots = tokio_rustls::rustls::RootCertStore::empty();
+            for cert in
+                rustls_native_certs::load_native_certs().expect("could not load platform certs")
+            {
+                roots
+                    .add(&tokio_rustls::rustls::Certificate(cert.to_vec()))
+                    .unwrap();
+            }
+
+            let client_config = ClientConfig::builder()
+                .with_safe_defaults()
+                .with_root_certificates(roots)
+                .with_no_client_auth();
+
+            mqttoptions.set_transport(Transport::tls_with_config(client_config.into()));
+        }
 
         //parse the mqtt authentication options
         if let Some((username, password)) = match (&config.username, &config.password) {
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index 2fd3fa3e..49983938 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -50,6 +50,7 @@ fn publish_one_message() {
             port: Some(1234),
             username: None,
             password: None,
+            tls: None,
         },
         "-test",
     );