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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151

//            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::fmt;

use crate::error::*;
use crate::packet::{Packet as P, PacketMut as PM, AsPacket, AsPacketMut};
use crate::size;
use crate::ip;
use crate::icmp::Kind;

/// Parameter Problem packet parser.
pub struct Packet<B> {
	buffer: B,
}

sized!(Packet,
	header {
		min:  8,
		max:  8,
		size: 8,
	}

	payload {
		min:  <ip::v4::Packet<()> as size::header::Min>::min(),
		max:  <ip::v4::Packet<()> as size::header::Max>::max(),
		size: p => {
			if let Ok(ip) = p.packet() {
				size::header::Size::size(&ip)
			}
			else {
				p.buffer.as_ref().len() - 8
			}
		},
	});

impl<B: AsRef<[u8]>> fmt::Debug for Packet<B> {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.debug_struct("icmp::parameter_problem::Packet")
			.field("pointer", &self.pointer())
			.field("packet", &self.packet())
			.finish()
	}
}

impl<B: AsRef<[u8]>> Packet<B> {
	/// Create a Parameter Problem packet without checking the buffer.
	pub fn unchecked(buffer: B) -> Packet<B> {
		Packet { buffer }
	}

	/// Parse a Parameter Problem packet, checking the buffer contents
	/// are correct.
	pub fn new(buffer: B) -> Result<Packet<B>> {
		use crate::size::header::Min;

		let packet = Packet::unchecked(buffer);

		if packet.buffer.as_ref().len() < Self::min() {
			Err(Error::SmallBuffer)?
		}

		match Kind::from(packet.buffer.as_ref()[0]) {
			Kind::ParameterProblem =>
				(),

			_ =>
				Err(Error::InvalidPacket)?
		}

		Ok(packet)
	}
}

impl<B: AsRef<[u8]>> Packet<B> {
	/// Convert the packet to its owned version.
	///
	/// # Notes
	///
	/// It would be nice if `ToOwned` could be implemented, but `Packet` already
	/// implements `Clone` and the impl would conflict.
	pub fn to_owned(&self) -> Packet<Vec<u8>> {
		Packet::unchecked(self.buffer.as_ref().to_vec())
	}
}

impl<B: AsRef<[u8]>> AsRef<[u8]> for Packet<B> {
	fn as_ref(&self) -> &[u8] {
		use crate::size::Size;

		&self.buffer.as_ref()[.. self.size()]
	}
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> AsMut<[u8]> for Packet<B> {
	fn as_mut(&mut self) -> &mut [u8] {
		use crate::size::Size;

		let size = self.size();
		&mut self.buffer.as_mut()[.. size]
	}
}

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

impl<'a, B: AsRef<[u8]> + AsMut<[u8]>> AsPacketMut<'a, Packet<&'a mut [u8]>> for B {
	fn as_packet_mut(&mut self) -> Result<Packet<&mut [u8]>> {
		Packet::new(self.as_mut())
	}
}

impl<B: AsRef<[u8]>> P for Packet<B> {
	fn split(&self) -> (&[u8], &[u8]) {
		let (header, payload) = self.buffer.as_ref().split_at(8);
		(&header[ .. 5], payload)
	}
}

impl<B: AsRef<[u8]> + AsMut<[u8]>> PM for Packet<B> {
	fn split_mut(&mut self) -> (&mut [u8], &mut [u8]) {
		let (header, payload) = self.buffer.as_mut().split_at_mut(8);
		(&mut header[.. 5], payload)
	}
}

impl<B: AsRef<[u8]>> Packet<B> {
	/// Pointer to the packet area that caused the problem.
	pub fn pointer(&self) -> u8 {
		self.buffer.as_ref()[4]
	}

	/// The packet that caused the problem.
	pub fn packet(&self) -> Result<ip::v4::Packet<&[u8]>> {
		ip::v4::Packet::new(&self.buffer.as_ref()[8 ..])
	}
}