net_parse/l2/
mod.rs

1use nom::{rest,be_u16};
2
3use {ParseOps,ConvError};
4use packet_writer::{PacketWriter,WriteFields};
5
6named!(bytes_to_ethernet<&[u8], EthHdr>, do_parse!(
7    src: take!(6) >>
8    dest: take!(6) >>
9    eth_type: be_u16 >>
10    (EthHdr { mac_src: src, mac_dest: dest, eth_type: EthType::from(eth_type) })
11));
12named!(strip_ethernet<&[u8]>, do_parse!(
13    take!(14) >>
14    inner_bytes: rest >>
15    (inner_bytes)
16));
17
18c_enum!(EthType, u16, {
19    IPv4 => 0x0800
20});
21
22#[derive(Debug,PartialEq)]
23pub struct EthHdr<'a> {
24    mac_src: &'a [u8],
25    mac_dest: &'a [u8],
26    eth_type: EthType,
27}
28
29impl<'a> ParseOps<'a> for EthHdr<'a> {
30    fn to_bytes(self) -> Result<Vec<u8>, ConvError> {
31        let mut pw = PacketWriter::new();
32        pw.write_bytes(self.mac_src)?;
33        pw.write_bytes(self.mac_dest)?;
34        <PacketWriter as WriteFields<Vec<u8>>>::write_u16::<u16>(
35            &mut pw, self.eth_type as u16
36        )?;
37        Ok(pw.get_result())
38    }
39
40    fn from_bytes(buf: &'a [u8]) -> Result<Self, ConvError> {
41        match bytes_to_ethernet(buf) {
42            Ok((_, ip)) => Ok(ip),
43            Err(e) => {
44                Err(ConvError(
45                    format!("Failed to parse - here is the remaining output: {:?}", e)
46                ))
47            },
48        }
49    }
50
51    fn strip_header(buf: &[u8]) -> Result<&[u8], ConvError> {
52        match strip_ethernet(buf) {
53            Ok((_, eth)) => Ok(eth),
54            Err(e) => {
55                Err(ConvError(
56                    format!("Failed to parse - here is the remaining output: {:?}", e)
57                ))
58            },
59        }
60    }
61}
62
63#[cfg(test)]
64mod test {
65    use super::*;
66
67    #[test]
68    fn test_write_header() {
69        assert_eq!(EthHdr { mac_src: &[1, 2, 3, 4, 5, 6],
70                            mac_dest: &[7, 8, 9, 10, 11, 12],
71                            eth_type: EthType::IPv4,
72        }.to_bytes().unwrap(), &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0x08, 0x00])
73    }
74
75    #[test]
76    fn test_parse_header() {
77        let s = &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0x08, 0x00, 15, 16, 17];
78        assert_eq!(EthHdr { mac_src: &[1, 2, 3, 4, 5, 6],
79                            mac_dest: &[7, 8, 9, 10, 11, 12],
80                            eth_type: EthType::IPv4 },
81                   EthHdr::from_bytes(s).unwrap())
82    }
83
84    #[test]
85    fn test_strip_header() {
86        let s = &[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17];
87        assert_eq!(EthHdr::strip_header(s).unwrap(), &[15, 16, 17])
88    }
89}
net_parse/l2/mod.rs

net_parse/l2/
mod.rs
