1 use crate::frame::{Error, Frame, Head, Kind, StreamId}; 2 use bytes::BufMut; 3 4 const ACK_FLAG: u8 = 0x1; 5 6 pub type Payload = [u8; 8]; 7 8 #[derive(Debug, Eq, PartialEq)] 9 pub 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. 16 const SHUTDOWN_PAYLOAD: Payload = [0x0b, 0x7b, 0xa2, 0xf0, 0x8b, 0x9b, 0xfe, 0x54]; 17 const USER_PAYLOAD: Payload = [0x3b, 0x7c, 0xdb, 0x7a, 0x0b, 0x87, 0x16, 0xb4]; 18 19 impl 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 new(payload: Payload) -> Ping32 pub fn new(payload: Payload) -> Ping { 33 Ping { 34 ack: false, 35 payload, 36 } 37 } 38 pong(payload: Payload) -> Ping39 pub fn pong(payload: Payload) -> Ping { 40 Ping { ack: true, payload } 41 } 42 is_ack(&self) -> bool43 pub fn is_ack(&self) -> bool { 44 self.ack 45 } 46 payload(&self) -> &Payload47 pub fn payload(&self) -> &Payload { 48 &self.payload 49 } 50 into_payload(self) -> Payload51 pub fn into_payload(self) -> Payload { 52 self.payload 53 } 54 55 /// Builds a `Ping` frame from a raw frame. load(head: Head, bytes: &[u8]) -> Result<Ping, Error>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 encode<B: BufMut>(&self, dst: &mut B)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 98 impl<T> From<Ping> for Frame<T> { from(src: Ping) -> Frame<T>99 fn from(src: Ping) -> Frame<T> { 100 Frame::Ping(src) 101 } 102 } 103