1 files changed, 102 insertions, 0 deletions
diff --git a/third_party/rust/h2/src/frame/ping.rs b/third_party/rust/h2/src/frame/ping.rs
new file mode 100644
index 0000000000..241d06ea17
--- /dev/null
+++ b/third_party/rust/h2/src/frame/ping.rs
@@ -0,0 +1,102 @@
+use crate::frame::{Error, Frame, Head, Kind, StreamId};
+use bytes::BufMut;
+
+const ACK_FLAG: u8 = 0x1;
+
+pub type Payload = [u8; 8];
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct Ping {
+    ack: bool,
+    payload: Payload,
+}
+
+// This was just 8 randomly generated bytes. We use something besides just
+// zeroes to distinguish this specific PING from any other.
+const SHUTDOWN_PAYLOAD: Payload = [0x0b, 0x7b, 0xa2, 0xf0, 0x8b, 0x9b, 0xfe, 0x54];
+const USER_PAYLOAD: Payload = [0x3b, 0x7c, 0xdb, 0x7a, 0x0b, 0x87, 0x16, 0xb4];
+
+impl Ping {
+    #[cfg(feature = "unstable")]
+    pub const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
+
+    #[cfg(not(feature = "unstable"))]
+    pub(crate) const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
+
+    #[cfg(feature = "unstable")]
+    pub const USER: Payload = USER_PAYLOAD;
+
+    #[cfg(not(feature = "unstable"))]
+    pub(crate) const USER: Payload = USER_PAYLOAD;
+
+    pub fn new(payload: Payload) -> Ping {
+        Ping {
+            ack: false,
+            payload,
+        }
+    }
+
+    pub fn pong(payload: Payload) -> Ping {
+        Ping { ack: true, payload }
+    }
+
+    pub fn is_ack(&self) -> bool {
+        self.ack
+    }
+
+    pub fn payload(&self) -> &Payload {
+        &self.payload
+    }
+
+    pub fn into_payload(self) -> Payload {
+        self.payload
+    }
+
+    /// Builds a `Ping` frame from a raw frame.
+    pub fn load(head: Head, bytes: &[u8]) -> Result<Ping, Error> {
+        debug_assert_eq!(head.kind(), crate::frame::Kind::Ping);
+
+        // PING frames are not associated with any individual stream. If a PING
+        // frame is received with a stream identifier field value other than
+        // 0x0, the recipient MUST respond with a connection error
+        // (Section 5.4.1) of type PROTOCOL_ERROR.
+        if !head.stream_id().is_zero() {
+            return Err(Error::InvalidStreamId);
+        }
+
+        // In addition to the frame header, PING frames MUST contain 8 octets of opaque
+        // data in the payload.
+        if bytes.len() != 8 {
+            return Err(Error::BadFrameSize);
+        }
+
+        let mut payload = [0; 8];
+        payload.copy_from_slice(bytes);
+
+        // The PING frame defines the following flags:
+        //
+        // ACK (0x1): When set, bit 0 indicates that this PING frame is a PING
+        //    response. An endpoint MUST set this flag in PING responses. An
+        //    endpoint MUST NOT respond to PING frames containing this flag.
+        let ack = head.flag() & ACK_FLAG != 0;
+
+        Ok(Ping { ack, payload })
+    }
+
+    pub fn encode<B: BufMut>(&self, dst: &mut B) {
+        let sz = self.payload.len();
+        tracing::trace!("encoding PING; ack={} len={}", self.ack, sz);
+
+        let flags = if self.ack { ACK_FLAG } else { 0 };
+        let head = Head::new(Kind::Ping, flags, StreamId::zero());
+
+        head.encode(sz, dst);
+        dst.put_slice(&self.payload);
+    }
+}
+
+impl<T> From<Ping> for Frame<T> {
+    fn from(src: Ping) -> Frame<T> {
+        Frame::Ping(src)
+    }
+}