pcap-file 3.0.0-rc.2

A crate to parse, read and write Pcap and PcapNg
Documentation 
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

//! Section Header Block.

use std::borrow::Cow;
use std::io::Write;

use byteorder_slice::byteorder::WriteBytesExt;
use byteorder_slice::result::ReadSlice;
use byteorder_slice::{BigEndian, ByteOrder, LittleEndian};
use derive_into_owned::IntoOwned;

use super::block_common::{Block, PcapNgBlock};
use super::opt_common::{CommonOption, PcapNgOption, WriteOptTo};
use crate::errors::PcapError;
use crate::pcapng::PcapNgState;
use crate::Endianness;


/// Section Header Block: it defines the most important characteristics of the capture file.
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub struct SectionHeaderBlock<'a> {
    /// Endianness of the section.
    pub endianness: Endianness,

    /// Major version of the format.
    /// Current value is 1.
    pub major_version: u16,

    /// Minor version of the format.
    /// Current value is 0.
    pub minor_version: u16,

    /// Length in bytes of the following section excluding this block.
    ///
    /// This block can be used to skip the section for faster navigation in
    /// large files. Length of -1i64 means that the length is unspecified.
    pub section_length: i64,

    /// Options
    pub options: Vec<SectionHeaderOption<'a>>,
}

impl<'a> PcapNgBlock<'a> for SectionHeaderBlock<'a> {
    fn from_slice<B: ByteOrder>(state: &PcapNgState, mut slice: &'a [u8]) -> Result<(&'a [u8], Self), PcapError> {
        if slice.len() < 16 {
            return Err(PcapError::InvalidField("SectionHeaderBlock: block length < 16"));
        }

        let magic = slice.read_u32::<BigEndian>().unwrap();
        let endianness = match magic {
            0x1A2B3C4D => Endianness::Big,
            0x4D3C2B1A => Endianness::Little,
            _ => return Err(PcapError::InvalidField("SectionHeaderBlock: invalid magic number")),
        };

        let (rem, major_version, minor_version, section_length, options) = match endianness {
            Endianness::Big => parse_inner::<BigEndian>(state, slice)?,
            Endianness::Little => parse_inner::<LittleEndian>(state, slice)?,
        };

        let block = SectionHeaderBlock { endianness, major_version, minor_version, section_length, options };

        return Ok((rem, block));

        #[allow(clippy::type_complexity)]
        fn parse_inner<'a, B: ByteOrder>(state: &PcapNgState, mut slice: &'a [u8]) -> Result<(&'a [u8], u16, u16, i64, Vec<SectionHeaderOption<'a>>), PcapError> {
            let maj_ver = slice.read_u16::<B>().unwrap();
            let min_ver = slice.read_u16::<B>().unwrap();
            let sec_len = slice.read_i64::<B>().unwrap();
            let (rem, opts) = SectionHeaderOption::opts_from_slice::<B>(state, None, slice)?;

            Ok((rem, maj_ver, min_ver, sec_len, opts))
        }
    }

    fn write_to<B: ByteOrder, W: Write>(&self, state: &PcapNgState, writer: &mut W) -> Result<usize, PcapError> {
        match self.endianness {
            Endianness::Big => writer.write_u32::<BigEndian>(0x1A2B3C4D)?,
            Endianness::Little => writer.write_u32::<LittleEndian>(0x1A2B3C4D)?,
        };

        writer.write_u16::<B>(self.major_version)?;
        writer.write_u16::<B>(self.minor_version)?;
        writer.write_i64::<B>(self.section_length)?;

        let opt_len = SectionHeaderOption::write_opts_to::<B, W>(&self.options, state, None, writer)?;

        Ok(16 + opt_len)
    }

    fn into_block(self) -> Block<'a> {
        Block::SectionHeader(self)
    }
}

impl Default for SectionHeaderBlock<'static> {
    fn default() -> Self {
        Self {
            endianness: Endianness::Big,
            major_version: 1,
            minor_version: 0,
            section_length: -1,
            options: vec![],
        }
    }
}


/// Section Header Block options
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub enum SectionHeaderOption<'a> {
    /// Description of the hardware used to create this section
    Hardware(Cow<'a, str>),

    /// Name of the operating system used to create this section
    OS(Cow<'a, str>),

    /// Name of the application used to create this section
    UserApplication(Cow<'a, str>),

    /// A common option applicable to any block type.
    Common(CommonOption<'a>),
}

impl<'a> PcapNgOption<'a> for SectionHeaderOption<'a> {
    fn from_slice<B: ByteOrder>(_state: &PcapNgState, _interface_id: Option<u32>, code: u16, slice: &'a [u8]) -> Result<Self, PcapError> {
        let opt = match code {
            2 => SectionHeaderOption::Hardware(Cow::Borrowed(std::str::from_utf8(slice)?)),
            3 => SectionHeaderOption::OS(Cow::Borrowed(std::str::from_utf8(slice)?)),
            4 => SectionHeaderOption::UserApplication(Cow::Borrowed(std::str::from_utf8(slice)?)),

            _ => SectionHeaderOption::Common(CommonOption::new::<B>(code, slice)?),
        };

        Ok(opt)
    }

    fn write_to<B: ByteOrder, W: Write>(&self, _state: &PcapNgState, _interface_id: Option<u32>, writer: &mut W) -> Result<usize, PcapError> {
        Ok(match self {
            SectionHeaderOption::Hardware(a) => a.write_opt_to::<B, W>(2, writer),
            SectionHeaderOption::OS(a) => a.write_opt_to::<B, W>(3, writer),
            SectionHeaderOption::UserApplication(a) => a.write_opt_to::<B, W>(4, writer),
            SectionHeaderOption::Common(a) => a.write_opt_to::<B, W>(a.code(), writer),
        }?)
    }
}