adding ethhdr type for linux/android for proper packet filtering.

[ref](https://docs.huihoo.com/doxygen/linux/kernel/3.7/structethhdr.html)

Author: devnexen

libc-test/build.rs

@@ -2301,6 +2301,8 @@ fn test_android(target: &str) {
         (struct_ == "sigaction" && field == "sa_sigaction") ||
         // signalfd had SIGSYS fields added in Android 4.19, but CI does not have that version yet.
         (struct_ == "signalfd_siginfo" && field == "ssi_call_addr") ||
+        // FIXME: `h_proto` is of type __be16 big endian version of __u16
+        (struct_ ==  "ethhdr" && field == "h_proto") ||
         // FIXME(android): Seems the type has been changed on NDK r26b
         (struct_ == "flock64" && (field == "l_start" || field == "l_len"))
     });
@@ -3918,6 +3920,10 @@ fn test_linux(target: &str) {
         if sparc64 && (ty == "Elf32_Rela" || ty == "Elf64_Rela") {
             return true;
         }
+        // FIXME: alignment issue with this arch
+        if loongarch64 && ty == "ethhdr" {
+            return true;
+        }
         match ty {
             // FIXME(sighandler): `sighandler_t` type is incorrect, see:
             // https://github.com/rust-lang/libc/issues/1359
@@ -4676,6 +4682,8 @@ fn test_linux(target: &str) {
         (struct_ == "ptp_perout_request" && field == "anonymous_1") ||
         // `anonymous_2` is an anonymous union
         (struct_ == "ptp_perout_request" && field == "anonymous_2") ||
+        // FIXME: `h_proto` is of type __be16 big endian version of __u16
+        (struct_ ==  "ethhdr" && field == "h_proto") ||
         // FIXME(linux): `adjust_phase` requires >= 5.7 kernel headers
         // FIXME(linux): `max_phase_adj` requires >= 5.19 kernel headers
         // the rsv field shrunk when those fields got added, so is omitted too

libc-test/semver/android.txt

@@ -3277,6 +3277,7 @@ epoll_create1
 epoll_ctl
 epoll_event
 epoll_wait
+ethhdr
 eventfd
 eventfd_read
 eventfd_write

libc-test/semver/linux-gnu.txt

@@ -590,6 +590,7 @@ dlmopen
 eaccess
 endutxent
 epoll_pwait2
+ethhdr
 euidaccess
 execveat
 explicit_bzero

src/unix/linux_like/android/mod.rs

@@ -34,6 +34,7 @@ pub type __u16 = c_ushort;
 pub type __s16 = c_short;
 pub type __u32 = c_uint;
 pub type __s32 = c_int;
+pub type __be16 = __u16;
 
 // linux/elf.h
 
@@ -643,6 +644,15 @@ s_no_extra_traits! {
         pub ifc_len: c_int,
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
     }
+
+    // linux/if_ether.h
+
+    #[repr(C, packed)]
+    pub struct ethhdr {
+        pub h_dest: [c_uchar; crate::ETH_ALEN as usize],
+        pub h_source: [c_uchar; crate::ETH_ALEN as usize],
+        pub h_proto: crate::__be16,
+    }
 }
 
 cfg_if! {
@@ -1025,6 +1035,33 @@ cfg_if! {
                     .finish()
             }
         }
+
+        impl Eq for ethhdr {}
+
+        impl PartialEq for ethhdr {
+            fn eq(&self, other: &ethhdr) -> bool {
+                self.h_dest
+                    .iter()
+                    .zip(other.h_dest.iter())
+                    .all(|(a, b)| a == b)
+                    && self
+                        .h_source
+                        .iter()
+                        .zip(other.h_source.iter())
+                        .all(|(a, b)| a == b)
+                    && self.h_proto == other.h_proto
+            }
+        }
+
+        impl fmt::Debug for ethhdr {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.debug_struct("ethhdr")
+                    .field("h_dest", &self.h_dest)
+                    .field("h_source", &self.h_source)
+                    .field("h_proto", &{ self.h_proto })
+                    .finish()
+            }
+        }
     }
 }
 

src/unix/linux_like/linux/gnu/mod.rs

@@ -7,6 +7,7 @@ pub type __rlimit_resource_t = c_uint;
 pub type Lmid_t = c_long;
 pub type regoff_t = c_int;
 pub type __kernel_rwf_t = c_int;
+pub type __be16 = crate::__u16;
 
 cfg_if! {
     if #[cfg(doc)] {
@@ -466,6 +467,15 @@ s_no_extra_traits! {
         __pad: [c_char; 4],
         __glibc_reserved: [c_char; 32],
     }
+
+    // linux/if_ether.h
+
+    #[repr(C, packed)]
+    pub struct ethhdr {
+        pub h_dest: [c_uchar; crate::ETH_ALEN as usize],
+        pub h_source: [c_uchar; crate::ETH_ALEN as usize],
+        pub h_proto: crate::__be16,
+    }
 }
 
 // Internal, for casts to access union fields
@@ -675,6 +685,33 @@ cfg_if! {
                 }
             }
         }
+
+        impl Eq for ethhdr {}
+
+        impl PartialEq for ethhdr {
+            fn eq(&self, other: &ethhdr) -> bool {
+                self.h_dest
+                    .iter()
+                    .zip(other.h_dest.iter())
+                    .all(|(a, b)| a == b)
+                    && self
+                        .h_source
+                        .iter()
+                        .zip(other.h_source.iter())
+                        .all(|(a, b)| a == b)
+                    && self.h_proto == other.h_proto
+            }
+        }
+
+        impl fmt::Debug for ethhdr {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.debug_struct("ethhdr")
+                    .field("h_dest", &self.h_dest)
+                    .field("h_source", &self.h_source)
+                    .field("h_proto", &{ self.h_proto })
+                    .finish()
+            }
+        }
     }
 }