Fix feature-related compilation issues.

Cargo.toml

@@ -32,12 +32,12 @@ url = "1.0"
 std = ["managed/std"]
 alloc = ["managed/alloc"]
 verbose = []
-ethernet = []
-"phy-raw_socket" = ["std", "libc"]
-"phy-tap_interface" = ["std", "libc"]
+ethernet = ["socket"]
+"phy-raw_socket" = ["std", "libc", "ethernet"]
+"phy-tap_interface" = ["std", "libc", "ethernet"]
 "proto-ipv4" = []
 "proto-igmp" = ["proto-ipv4"]
-"proto-dhcpv4" = ["proto-ipv4", "socket-raw"]
+"proto-dhcpv4" = ["proto-ipv4", "socket-raw", "ethernet"]
 "proto-ipv6" = []
 "socket" = []
 "socket-raw" = ["socket"]

src/lib.rs

@@ -83,6 +83,20 @@ compile_error!("at least one socket needs to be enabled"); */
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
+#[cfg(not(any(feature = "proto-ipv4", feature = "proto-ipv6")))]
+compile_error!("You must enable at least one of the following features: proto-ipv4, proto-ipv6");
+
+#[cfg(all(
+    feature = "socket",
+    not(any(
+        feature = "socket-raw",
+        feature = "socket-udp",
+        feature = "socket-tcp",
+        feature = "socket-icmp",
+    ))
+))]
+compile_error!("If you enable the socket feature, you must enable at least one of the following features: socket-raw, socket-udp, socket-tcp, socket-icmp");
+
 use core::fmt;
 
 #[macro_use]