Move ip_mtu back to smoltcp

Author: bugadani

smoltcp-device/src/lib.rs

@@ -201,19 +201,6 @@ pub struct DeviceCapabilities {
     pub checksum: ChecksumCapabilities,
 }
 
-impl DeviceCapabilities {
-    pub fn ip_mtu(&self) -> usize {
-        match self.medium {
-            #[cfg(feature = "medium-ethernet")]
-            Medium::Ethernet => self.max_transmission_unit - 14,
-            #[cfg(feature = "medium-ip")]
-            Medium::Ip => self.max_transmission_unit,
-            #[cfg(feature = "medium-ieee802154")]
-            Medium::Ieee802154 => self.max_transmission_unit, // TODO(thvdveld): what is the MTU for Medium::IEEE802
-        }
-    }
-}
-
 /// Type of medium of a device.
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]

src/iface/interface/mod.rs

@@ -783,7 +783,15 @@ impl InterfaceInner {
 
     #[allow(unused)] // unused depending on which sockets are enabled
     pub(crate) fn ip_mtu(&self) -> usize {
-        self.caps.ip_mtu()
+        match self.caps.medium {
+            #[cfg(feature = "medium-ethernet")]
+            Medium::Ethernet => self.caps.max_transmission_unit - 14,
+            #[cfg(feature = "medium-ip")]
+            Medium::Ip => self.caps.max_transmission_unit,
+            #[cfg(feature = "medium-ieee802154")]
+            Medium::Ieee802154 => self.caps.max_transmission_unit, // TODO(thvdveld): what is the MTU for Medium::IEEE802
+            _ => unimplemented!(),
+        }
     }
 
     #[allow(unused)] // unused depending on which sockets are enabled, and in tests
@@ -1210,7 +1218,7 @@ impl InterfaceInner {
             #[cfg(feature = "proto-ipv4")]
             IpRepr::Ipv4(repr) => {
                 // If we have an IPv4 packet, then we need to check if we need to fragment it.
-                if total_ip_len > self.caps.ip_mtu() {
+                if total_ip_len > self.ip_mtu() {
                     #[cfg(feature = "proto-ipv4-fragmentation")]
                     {
                         net_debug!("start fragmentation");
@@ -1219,7 +1227,7 @@ impl InterfaceInner {
                         let tx_len = self.caps.max_transmission_unit;
 
                         let ip_header_len = repr.buffer_len();
-                        let first_frag_ip_len = self.caps.ip_mtu();
+                        let first_frag_ip_len = self.ip_mtu();
 
                         if frag.buffer.len() < total_ip_len {
                             net_debug!(
@@ -1305,7 +1313,7 @@ impl InterfaceInner {
             #[cfg(feature = "proto-ipv6")]
             IpRepr::Ipv6(_) => {
                 // Check if we need to fragment it.
-                if total_ip_len > self.caps.ip_mtu() {
+                if total_ip_len > self.ip_mtu() {
                     net_debug!("IPv6 fragmentation support is unimplemented. Dropping.");
                     Ok(())
                 } else {