diff --git a/Cargo.lock b/Cargo.lock
index 79ec928a66..e12d606f91 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -28,15 +28,6 @@ name = "arg_parser"
 version = "0.1.0"
 source = "git+https://gitlab.redox-os.org/redox-os/arg-parser.git#1c434b55f3e1a0375ebcca85b3e88db7378e82fa"
 
-[[package]]
-name = "atomic-polyfill"
-version = "1.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8cf2bce30dfe09ef0bfaef228b9d414faaf7e563035494d7fe092dba54b300f4"
-dependencies = [
- "critical-section",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -114,12 +105,6 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
-[[package]]
-name = "critical-section"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
-
 [[package]]
 name = "crossbeam-channel"
 version = "0.5.13"
@@ -179,23 +164,20 @@ dependencies = [
 
 [[package]]
 name = "hash32"
-version = "0.2.1"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0c35f58762feb77d74ebe43bdbc3210f09be9fe6742234d573bacc26ed92b67"
+checksum = "47d60b12902ba28e2730cd37e95b8c9223af2808df9e902d4df49588d1470606"
 dependencies = [
  "byteorder 1.5.0",
 ]
 
 [[package]]
 name = "heapless"
-version = "0.7.17"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cdc6457c0eb62c71aac4bc17216026d8410337c4126773b9c5daba343f17964f"
+checksum = "0bfb9eb618601c89945a70e254898da93b13be0388091d42117462b265bb3fad"
 dependencies = [
- "atomic-polyfill",
  "hash32",
- "rustc_version",
- "spin",
  "stable_deref_trait",
 ]
 
@@ -270,16 +252,6 @@ dependencies = [
  "redox_syscall",
 ]
 
-[[package]]
-name = "lock_api"
-version = "0.4.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "07af8b9cdd281b7915f413fa73f29ebd5d55d0d3f0155584dade1ff18cea1b17"
-dependencies = [
- "autocfg",
- "scopeguard",
-]
-
 [[package]]
 name = "log"
 version = "0.4.22"
@@ -486,27 +458,6 @@ version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20145670ba436b55d91fc92d25e71160fbfbdd57831631c8d7d36377a476f1cb"
 
-[[package]]
-name = "rustc_version"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfcb3a22ef46e85b45de6ee7e79d063319ebb6594faafcf1c225ea92ab6e9b92"
-dependencies = [
- "semver",
-]
-
-[[package]]
-name = "scopeguard"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
-
-[[package]]
-name = "semver"
-version = "1.0.23"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61697e0a1c7e512e84a621326239844a24d8207b4669b41bc18b32ea5cbf988b"
-
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -521,9 +472,9 @@ checksum = "3c5e1a9a646d36c3599cd173a41282daf47c44583ad367b8e6837255952e5c67"
 
 [[package]]
 name = "smoltcp"
-version = "0.10.0"
+version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d2e3a36ac8fea7b94e666dfa3871063d6e0a5c9d5d4fec9a1a6b7b6760f0229"
+checksum = "dad095989c1533c1c266d9b1e8d70a1329dd3723c3edac6d03bbd67e7bf6f4bb"
 dependencies = [
  "bitflags 1.3.2",
  "byteorder 1.5.0",
@@ -534,15 +485,6 @@ dependencies = [
  "managed",
 ]
 
-[[package]]
-name = "spin"
-version = "0.9.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
-dependencies = [
- "lock_api",
-]
-
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.0"
diff --git a/Cargo.toml b/Cargo.toml
index 221b2ec6a3..a1efb585eb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,13 +32,13 @@ default-features = false
 features = ["release_max_level_warn"]
 
 [dependencies.smoltcp]
-version = "0.10.0"
+version = "0.12.0"
 default-features = false
 features = [
     "std",
     "medium-ethernet", "medium-ip",
     "proto-ipv4",
-    "socket-raw", "socket-icmp", "socket-udp", "socket-tcp",
+    "socket-raw", "socket-icmp", "socket-udp", "socket-tcp", "socket-tcp-cubic",
     "iface-max-addr-count-8",
     "log"
 ]
diff --git a/src/smolnetd/link/ethernet.rs b/src/smolnetd/link/ethernet.rs
index 58dfab3d13..5f32a479dd 100644
--- a/src/smolnetd/link/ethernet.rs
+++ b/src/smolnetd/link/ethernet.rs
@@ -137,7 +137,11 @@ impl EthernetLink {
                     return;
                 }
 
-                if !source_hardware_addr.is_unicast() || !source_protocol_addr.is_unicast() {
+                if !source_hardware_addr.is_unicast()
+                    || source_protocol_addr.is_broadcast()
+                    || source_protocol_addr.is_multicast()
+                    || source_protocol_addr.is_unspecified()
+                {
                     return;
                 }
 
diff --git a/src/smolnetd/router/mod.rs b/src/smolnetd/router/mod.rs
index 40a360ecf0..3cfd0a2fea 100644
--- a/src/smolnetd/router/mod.rs
+++ b/src/smolnetd/router/mod.rs
@@ -178,7 +178,7 @@ pub struct RxToken<'a> {
 impl<'a> smoltcp::phy::RxToken for RxToken<'a> {
     fn consume<R, F>(self, f: F) -> R
     where
-        F: FnOnce(&mut [u8]) -> R,
+        F: FnOnce(&[u8]) -> R,
     {
         let ((), buf) = self
             .rx_buffer
diff --git a/src/smolnetd/scheme/netcfg/mod.rs b/src/smolnetd/scheme/netcfg/mod.rs
index 95492838ef..846bcddfdb 100644
--- a/src/smolnetd/scheme/netcfg/mod.rs
+++ b/src/smolnetd/scheme/netcfg/mod.rs
@@ -82,7 +82,7 @@ fn mk_root_node(
                     if cur_value.is_none() {
                         let ip = Ipv4Address::from_str(line.trim())
                             .map_err(|_| SyscallError::new(syscall::EINVAL))?;
-                        if !ip.is_unicast() {
+                        if ip.is_broadcast() || ip.is_multicast() || ip.is_unspecified() {
                             return Err(SyscallError::new(syscall::EINVAL));
                         }
                         *cur_value = Some(ip);