use the cmsg storage for socket v1

.github/workflows/ci.yml

@@ -678,9 +678,7 @@ jobs:
           ! grep -q '[^[:space:]]' /tmp/typos.json
 
   kani:
-    # Some of the kani proofs use quite a bit of memory so we need larger instances
-    # https://docs.github.com/en/actions/using-github-hosted-runners/using-larger-runners#machine-specs-for-larger-runners
-    runs-on: ubuntu-latest-8-cores
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:

quic/s2n-quic-platform/src/message/cmsg.rs

@@ -61,7 +61,7 @@ pub type UdpGro = libc::c_int;
 pub type IpTos = libc::c_int;
 
 #[repr(align(8))] // the storage needs to be aligned to the same as `cmsghdr`
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct Storage([u8; MAX_LEN]);
 
 impl Default for Storage {

quic/s2n-quic-platform/src/message/msg.rs

@@ -380,7 +380,7 @@ pub struct Storage<Payloads> {
 
     // this field holds references to allocated msg_names, but is never read directly
     #[allow(dead_code)]
-    pub(crate) cmsgs: Pin<Box<[u8]>>,
+    pub(crate) cmsgs: Pin<Box<[cmsg::Storage]>>,
 
     /// The maximum payload for any given message
     mtu: usize,
@@ -434,19 +434,16 @@ impl<Payloads: crate::buffer::Buffer> Ring<Payloads> {
         let mut payloads = Pin::new(payloads);
         let mut iovecs = Pin::new(vec![unsafe { zeroed() }; capacity].into_boxed_slice());
         let mut msg_names = Pin::new(vec![unsafe { zeroed() }; capacity].into_boxed_slice());
-        let mut cmsgs = Pin::new(vec![0u8; capacity * cmsg::MAX_LEN].into_boxed_slice());
+        let mut cmsgs = Pin::new(vec![cmsg::Storage::default(); capacity].into_boxed_slice());
 
         // double message capacity to enable contiguous access
         let mut messages = Vec::with_capacity(capacity * 2);
 
         let mut payload_buf = &mut payloads.as_mut()[..];
-        let mut cmsg_buf = &mut cmsgs.as_mut()[..];
 
         for index in 0..capacity {
             let (payload, remaining) = payload_buf.split_at_mut(mtu * max_gso);
             payload_buf = remaining;
-            let (cmsg, remaining) = cmsg_buf.split_at_mut(cmsg::MAX_LEN);
-            cmsg_buf = remaining;
 
             let mut iovec = unsafe { zeroed::<iovec>() };
             iovec.iov_base = payload.as_mut_ptr() as _;
@@ -457,8 +454,8 @@ impl<Payloads: crate::buffer::Buffer> Ring<Payloads> {
                 (&mut iovecs[index]) as *mut _,
                 (&mut msg_names[index]) as *mut _ as *mut _,
                 size_of::<sockaddr_in6>(),
-                cmsg as *mut _ as *mut _,
-                cmsg::MAX_LEN,
+                cmsgs[index].as_mut_ptr() as *mut _,
+                cmsgs[index].len(),
             );
 
             messages.push(msg);

quic/s2n-quic-platform/src/socket/ring.rs

@@ -374,6 +374,8 @@ mod tests {
         ($name:ident, $msg:ty) => {
             #[test]
             #[cfg_attr(kani, kani::proof, kani::solver(cadical), kani::unwind(3))]
+            #[cfg(any(not(kani), kani_slow))] // this test takes too much memory for our CI
+                                              // environment
             fn $name() {
                 check!().with_type::<Counts>().for_each(|counts| {
                     let entries = if cfg!(kani) { 2 } else { 16 };