h2/frame/
ping.rs

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1use crate::frame::{Error, Frame, Head, Kind, StreamId};
2use bytes::BufMut;
3
4const ACK_FLAG: u8 = 0x1;
5
6pub type Payload = [u8; 8];
7
8#[derive(Debug, Eq, PartialEq)]
9pub struct Ping {
10    ack: bool,
11    payload: Payload,
12}
13
14// This was just 8 randomly generated bytes. We use something besides just
15// zeroes to distinguish this specific PING from any other.
16const SHUTDOWN_PAYLOAD: Payload = [0x0b, 0x7b, 0xa2, 0xf0, 0x8b, 0x9b, 0xfe, 0x54];
17const USER_PAYLOAD: Payload = [0x3b, 0x7c, 0xdb, 0x7a, 0x0b, 0x87, 0x16, 0xb4];
18
19impl Ping {
20    #[cfg(feature = "unstable")]
21    pub const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
22
23    #[cfg(not(feature = "unstable"))]
24    pub(crate) const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
25
26    #[cfg(feature = "unstable")]
27    pub const USER: Payload = USER_PAYLOAD;
28
29    #[cfg(not(feature = "unstable"))]
30    pub(crate) const USER: Payload = USER_PAYLOAD;
31
32    pub fn new(payload: Payload) -> Ping {
33        Ping {
34            ack: false,
35            payload,
36        }
37    }
38
39    pub fn pong(payload: Payload) -> Ping {
40        Ping { ack: true, payload }
41    }
42
43    pub fn is_ack(&self) -> bool {
44        self.ack
45    }
46
47    pub fn payload(&self) -> &Payload {
48        &self.payload
49    }
50
51    pub fn into_payload(self) -> Payload {
52        self.payload
53    }
54
55    /// Builds a `Ping` frame from a raw frame.
56    pub fn load(head: Head, bytes: &[u8]) -> Result<Ping, Error> {
57        debug_assert_eq!(head.kind(), crate::frame::Kind::Ping);
58
59        // PING frames are not associated with any individual stream. If a PING
60        // frame is received with a stream identifier field value other than
61        // 0x0, the recipient MUST respond with a connection error
62        // (Section 5.4.1) of type PROTOCOL_ERROR.
63        if !head.stream_id().is_zero() {
64            return Err(Error::InvalidStreamId);
65        }
66
67        // In addition to the frame header, PING frames MUST contain 8 octets of opaque
68        // data in the payload.
69        if bytes.len() != 8 {
70            return Err(Error::BadFrameSize);
71        }
72
73        let mut payload = [0; 8];
74        payload.copy_from_slice(bytes);
75
76        // The PING frame defines the following flags:
77        //
78        // ACK (0x1): When set, bit 0 indicates that this PING frame is a PING
79        //    response. An endpoint MUST set this flag in PING responses. An
80        //    endpoint MUST NOT respond to PING frames containing this flag.
81        let ack = head.flag() & ACK_FLAG != 0;
82
83        Ok(Ping { ack, payload })
84    }
85
86    pub fn encode<B: BufMut>(&self, dst: &mut B) {
87        let sz = self.payload.len();
88        tracing::trace!("encoding PING; ack={} len={}", self.ack, sz);
89
90        let flags = if self.ack { ACK_FLAG } else { 0 };
91        let head = Head::new(Kind::Ping, flags, StreamId::zero());
92
93        head.encode(sz, dst);
94        dst.put_slice(&self.payload);
95    }
96}
97
98impl<T> From<Ping> for Frame<T> {
99    fn from(src: Ping) -> Frame<T> {
100        Frame::Ping(src)
101    }
102}
h2/frame/ping.rs

h2/frame/
ping.rs
