1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

//            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//                    Version 2, December 2004
//
// Copyleft (ↄ) meh. <meh@schizofreni.co> | http://meh.schizofreni.co
//
// Everyone is permitted to copy and distribute verbatim or modified
// copies of this license document, and changing it is allowed as long
// as the name is changed.
//
//            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
//
//  0. You just DO WHAT THE FUCK YOU WANT TO.

use std::io::Cursor;
use byteorder::{WriteBytesExt, BigEndian};

use crate::error::*;
use crate::buffer::{self, Buffer};
use crate::builder::{Builder as Build, Finalization};
use crate::packet::{AsPacket, AsPacketMut};
use crate::icmp::builder;
use crate::icmp::Kind;
use crate::icmp::echo::Packet;

/// Echo Request/Reply packet builder.
#[derive(Debug)]
pub struct Builder<B: Buffer = buffer::Dynamic> {
	buffer:    B,
	finalizer: Finalization,

	kind:    bool,
	payload: bool,
}

impl<B: Buffer> Build<B> for Builder<B> {
	fn with(mut buffer: B) -> Result<Self> {
		buffer.next(8)?;

		Ok(Builder {
			buffer:    buffer,
			finalizer: Default::default(),

			kind:    false,
			payload: false,
		})
	}

	fn finalizer(&mut self) -> &mut Finalization {
		&mut self.finalizer
	}

	fn build(mut self) -> Result<B::Inner> {
		if !self.kind {
			Err(Error::InvalidPacket)?
		}

		builder::prepare(&mut self.finalizer, &self.buffer);

		let mut buffer = self.buffer.into_inner();
		self.finalizer.finalize(buffer.as_mut())?;
		Ok(buffer)
	}
}

impl Default for Builder<buffer::Dynamic> {
	fn default() -> Self {
		Builder::with(buffer::Dynamic::default()).unwrap()
	}
}

impl<'a, B: Buffer> AsPacket<'a, Packet<&'a [u8]>> for Builder<B> {
	fn as_packet(&self) -> Result<Packet<&[u8]>> {
		Packet::new(self.buffer.data())
	}
}

impl<'a, B: Buffer> AsPacketMut<'a, Packet<&'a mut [u8]>> for Builder<B> {
	fn as_packet_mut(&mut self) -> Result<Packet<&mut [u8]>> {
		Packet::new(self.buffer.data_mut())
	}
}

impl<B: Buffer> Builder<B> {
	/// Make it a request.
	pub fn request(mut self) -> Result<Self> {
		self.kind = true;
		self.buffer.data_mut()[0] = Kind::EchoRequest.into();

		Ok(self)
	}

	/// Make it a reply.
	pub fn reply(mut self) -> Result<Self> {
		self.kind = true;
		self.buffer.data_mut()[0] = Kind::EchoReply.into();

		Ok(self)
	}

	/// Packet identifier.
	pub fn identifier(mut self, value: u16) -> Result<Self> {
		Cursor::new(&mut self.buffer.data_mut()[4 ..])
			.write_u16::<BigEndian>(value)?;

		Ok(self)
	}

	/// Packet sequence.
	pub fn sequence(mut self, value: u16) -> Result<Self> {
		Cursor::new(&mut self.buffer.data_mut()[6 ..])
			.write_u16::<BigEndian>(value)?;

		Ok(self)
	}

	/// Payload for the packet.
	pub fn payload<'a, T: IntoIterator<Item = &'a u8>>(mut self, value: T) -> Result<Self> {
		if self.payload {
			Err(Error::InvalidPacket)?
		}

		self.payload = true;

		for byte in value {
			self.buffer.more(1)?;
			*self.buffer.data_mut().last_mut().unwrap() = *byte;
		}

		Ok(self)
	}
}