fix(apple): define in6_ifreq locally so iOS targets build with libc 0.2.190

.github/workflows/ci.yml

@@ -48,6 +48,27 @@ jobs:
       - name: Run cargo check with all features
         run: cargo check --all-features
 
+  apple-mobile:
+    name: Check iOS
+    runs-on: macOS-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target:
+          - aarch64-apple-ios
+          - aarch64-apple-ios-sim
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust Toolchain
+        run: rustup toolchain install stable --profile minimal --no-self-update --target ${{ matrix.target }}
+
+      - uses: swatinem/rust-cache@v2
+
+      - name: Run cargo check
+        run: cargo check --target ${{ matrix.target }}
+
   cross:
     name: Cross compile
     runs-on: ubuntu-latest

src/os/darwin/ipv6_addr_flags.rs

@@ -9,14 +9,32 @@ const IN6_IFF_DUPLICATED: u32 = 0x04;
 const IN6_IFF_DEPRECATED: u32 = 0x10;
 const IN6_IFF_TEMPORARY: u32 = 0x80;
 
+// `libc` only exposes `in6_ifreq` on macOS (`<netinet6/in6_var.h>` is not part of the
+// iOS SDK), so define it here to build for every Apple target. `SIOCGIFAFLAG_IN6` encodes
+// `sizeof(struct in6_ifreq)` (0x120 = 288 bytes), so the union is padded to 272 bytes.
+#[repr(C)]
+struct In6Ifreq {
+    ifr_name: [libc::c_char; libc::IFNAMSIZ],
+    ifr_ifru: In6IfreqUnion,
+}
+
+#[repr(C)]
+union In6IfreqUnion {
+    ifru_addr: libc::sockaddr_in6,
+    ifru_flags6: libc::c_int,
+    // 8-byte aligned, as `in6_ifstat` holds u64 counters.
+    _size: [u64; 34],
+}
+
 pub(crate) fn get_ipv6_addr_flags(ifname: &str, addr: &Ipv6Addr) -> Ipv6AddrFlags {
     unsafe {
         let fd = libc::socket(libc::AF_INET6, libc::SOCK_DGRAM, 0);
         if fd < 0 {
             return Ipv6AddrFlags::default();
         }
 
-        let mut req: libc::in6_ifreq = std::mem::zeroed();
+        let mut req: In6Ifreq = std::mem::zeroed();
+        const _: () = assert!(std::mem::size_of::<In6Ifreq>() == 0x120);
 
         let name_bytes = ifname.as_bytes();
         let copy_len = name_bytes.len().min(libc::IFNAMSIZ - 1);