Implement TCP stream ring buffers.
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@ -14,11 +14,14 @@ use Error;
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use wire::{InternetAddress as Address, InternetProtocolType as ProtocolType};
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use wire::{InternetAddress as Address, InternetProtocolType as ProtocolType};
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mod udp;
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mod udp;
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mod tcp;
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pub use self::udp::Packet as UdpPacket;
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pub use self::udp::Packet as UdpPacket;
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pub use self::udp::Buffer as UdpBuffer;
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pub use self::udp::Buffer as UdpBuffer;
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pub use self::udp::UdpSocket as UdpSocket;
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pub use self::udp::UdpSocket as UdpSocket;
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pub use self::tcp::Buffer as TcpBuffer;
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/// A packet representation.
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/// A packet representation.
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///
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///
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/// This interface abstracts the various types of packets layered under the IP protocol,
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/// This interface abstracts the various types of packets layered under the IP protocol,
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@ -0,0 +1,74 @@
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use Managed;
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/// A TCP stream ring buffer.
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#[derive(Debug)]
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pub struct Buffer<'a> {
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storage: Managed<'a, [u8]>,
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read_at: usize,
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length: usize
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}
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impl<'a> Buffer<'a> {
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/// Create a packet buffer with the given storage.
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pub fn new<T>(storage: T) -> Buffer<'a>
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where T: Into<Managed<'a, [u8]>> {
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Buffer {
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storage: storage.into(),
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read_at: 0,
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length: 0
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}
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}
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/// Enqueue a slice of octets up to the given size into the buffer, and return a pointer
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/// to the slice.
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///
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/// The returned slice may be shorter than requested, as short as an empty slice,
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/// if there is not enough contiguous free space in the buffer.
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pub fn enqueue(&mut self, mut size: usize) -> &mut [u8] {
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let write_at = (self.read_at + self.length) % self.storage.len();
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// We can't enqueue more than there is free space.
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let free = self.storage.len() - self.length;
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if size > free { size = free }
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// We can't contiguously enqueue past the beginning of the storage.
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let until_end = self.storage.len() - write_at;
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if size > until_end { size = until_end }
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self.length += size;
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&mut self.storage[write_at..write_at + size]
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}
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/// Dequeue a slice of octets up to the given size from the buffer, and return a pointer
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/// to the slice.
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///
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/// The returned slice may be shorter than requested, as short as an empty slice,
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/// if there is not enough contiguous filled space in the buffer.
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pub fn dequeue(&mut self, mut size: usize) -> &[u8] {
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let read_at = self.read_at;
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// We can't dequeue more than was queued.
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if size > self.length { size = self.length }
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// We can't contiguously dequeue past the end of the storage.
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let until_end = self.storage.len() - self.read_at;
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if size > until_end { size = until_end }
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self.read_at = (self.read_at + size) % self.storage.len();
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self.length -= size;
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&self.storage[read_at..read_at + size]
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test_buffer() {
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let mut buffer = Buffer::new(vec![0; 8]); // ........
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buffer.enqueue(6).copy_from_slice(b"foobar"); // foobar..
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assert_eq!(buffer.dequeue(3), b"foo"); // ...bar..
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buffer.enqueue(6).copy_from_slice(b"ba"); // ...barba
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buffer.enqueue(4).copy_from_slice(b"zho"); // zhobarba
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assert_eq!(buffer.dequeue(6), b"barba"); // zho.....
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assert_eq!(buffer.dequeue(8), b"zho"); // ........
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buffer.enqueue(8).copy_from_slice(b"gefug"); // ...gefug
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}
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}
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@ -33,7 +33,7 @@ impl<'a> Packet<'a> {
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}
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}
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}
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}
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/// An UDP packet buffer.
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/// An UDP packet ring buffer.
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#[derive(Debug)]
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#[derive(Debug)]
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pub struct Buffer<'a, 'b: 'a> {
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pub struct Buffer<'a, 'b: 'a> {
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storage: Managed<'a, [Packet<'b>]>,
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storage: Managed<'a, [Packet<'b>]>,
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