Merge #509

509: Add static IP address as a build feature r=ryan-summers a=svrotter

In some cases it might be advantageous to set a static IP address for Stabilizer e.g. if it is used in an embedded environment that doesn't support DHCP or troubleshooting problems with DHCP negotiation.
This PR add this functionality as a build feature.

Co-authored-by: Sven Rotter <s.rotter@tu-berlin.de>

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+* Optional specification of a static IP address ([#509](https://github.com/quartiq/stabilizer/pull/509))
 * Telemetry ([#341](https://github.com/quartiq/stabilizer/pull/341))
 * Logging via RTT (real time tracing) over SWD/JTAG instead of semihosting
   for fast and low-overhead debugging ([#393](https://github.com/quartiq/stabilizer/pull/393) [#391](https://github.com/quartiq/stabilizer/pull/391) [#358](https://github.com/quartiq/stabilizer/pull/358))

book/src/setup.md

@@ -27,6 +27,8 @@ Stabilizer supports 10Base-T or 100Base-T with Auto MDI-X.
 Stabilizer uses DHCP to obtain its network configuration information. Ensure there is a
 properly configured DHCP server running on the network segment that Stabilizer is
 connected to.
+Alternatively, a static IP can be enforced in the firmware build command by specifying
+the environmental variable `STATIC_IP` analogous to how a specific broker IP is set.
 
 > **Note:** If Stabilizer is connected directly to an Ubuntu system (for example using a USB-Ethernet dongle) 
 you can set the IPv4 settings of this Ethernet connection in the Ubuntu network settings to

src/hardware/setup.rs

@@ -695,17 +695,18 @@ pub fn setup(
 
         unsafe { ethernet::enable_interrupt() };
 
+        // Configure IP address according to DHCP socket availability
+        let ip_addrs: smoltcp::wire::IpAddress = option_env!("STATIC_IP")
+            .unwrap_or("0.0.0.0")
+            .parse()
+            .unwrap();
+
         // Note(unwrap): The hardware configuration function is only allowed to be called once.
         // Unwrapping is intended to panic if called again to prevent re-use of global memory.
         let store =
             cortex_m::singleton!(: NetStorage = NetStorage::default()).unwrap();
 
-        store.ip_addrs[0] = smoltcp::wire::IpCidr::new(
-            smoltcp::wire::IpAddress::Ipv4(
-                smoltcp::wire::Ipv4Address::UNSPECIFIED,
-            ),
-            0,
-        );
+        store.ip_addrs[0] = smoltcp::wire::IpCidr::new(ip_addrs, 24);
 
         let mut routes =
             smoltcp::iface::Routes::new(&mut store.routes_cache[..]);
@@ -726,7 +727,9 @@ pub fn setup(
         .routes(routes)
         .finalize();
 
-        interface.add_socket(smoltcp::socket::Dhcpv4Socket::new());
+        if ip_addrs.is_unspecified() {
+            interface.add_socket(smoltcp::socket::Dhcpv4Socket::new());
+        }
 
         for storage in store.tcp_socket_storage[..].iter_mut() {
             let tcp_socket = {