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

@@ -2105,6 +2105,8 @@ 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: Seems the type has been changed on NDK r26b
         (struct_ == "flock64" && (field == "l_start" || field == "l_len"))
     });
@@ -3680,6 +3682,10 @@ 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_t` type is incorrect, see:
             // https://github.com/rust-lang/libc/issues/1359
@@ -4386,6 +4392,8 @@ 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

@@ -3230,6 +3230,7 @@ epoll_create1
 epoll_ctl
 epoll_event
 epoll_wait
+ethhdr
 eventfd
 eventfd_read
 eventfd_write

libc-test/semver/linux.txt

@@ -3722,6 +3722,7 @@ epoll_params
 epoll_pwait
 epoll_wait
 erand48
+ethhdr
 eventfd
 eventfd_read
 eventfd_write

src/unix/linux_like/android/mod.rs

@@ -517,6 +517,11 @@ s! {
         pub ifr6_prefixlen: u32,
         pub ifr6_ifindex: c_int,
     }
+
+    // is __be16 __bitwise __u16
+    pub struct __c_anonymous___be16 {
+        __priv: [crate::__u8; 2],
+    }
 }
 
 s_no_extra_traits! {
@@ -638,6 +643,15 @@ s_no_extra_traits! {
         pub ifc_len: c_int,
         pub ifc_ifcu: __c_anonymous_ifc_ifcu,
     }
+
+    // linux/if_ether.h
+
+    #[repr(C, align(1))]
+    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: __c_anonymous___be16,
+    }
 }
 
 cfg_if! {
@@ -1020,6 +1034,31 @@ 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)
+            }
+        }
+
+        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)
+                    .finish()
+            }
+        }
     }
 }
 

src/unix/linux_like/linux/mod.rs

@@ -1319,6 +1319,11 @@ s! {
         pub propagation: crate::__u64,
         pub userns_fd: crate::__u64,
     }
+
+    // is __be16 __bitwise __u16
+    pub struct __c_anonymous___be16 {
+        __priv: [crate::__u8; 2],
+    }
 }
 
 cfg_if! {
@@ -1784,6 +1789,16 @@ s_no_extra_traits! {
         pub request: xsk_tx_metadata_request,
         pub completion: xsk_tx_metadata_completion,
     }
+
+    // linux/if_ether.h
+
+    #[cfg(not(target_arch = "loongarch64"))]
+    #[repr(C, align(1))]
+    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: __c_anonymous___be16,
+    }
 }
 
 cfg_if! {
@@ -2211,6 +2226,34 @@ cfg_if! {
                     .finish()
             }
         }
+
+        #[cfg(not(target_arch = "loongarch64"))]
+        impl Eq for ethhdr {}
+
+        #[cfg(not(target_arch = "loongarch64"))]
+        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)
+            }
+        }
+
+        #[cfg(not(target_arch = "loongarch64"))]
+        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)
+                    .finish()
+            }
+        }
     }
 }