pcap_file/pcapng/blocks/
section_header.rs

1//! Section Header Block.
2
3use std::borrow::Cow;
4use std::io::{Result as IoResult, Write};
5
6use byteorder_slice::byteorder::WriteBytesExt;
7use byteorder_slice::result::ReadSlice;
8use byteorder_slice::{BigEndian, ByteOrder, LittleEndian};
9use derive_into_owned::IntoOwned;
10
11use super::block_common::{Block, PcapNgBlock};
12use super::opt_common::{CustomBinaryOption, CustomUtf8Option, PcapNgOption, UnknownOption, WriteOptTo};
13use crate::errors::PcapError;
14use crate::Endianness;
15
16
17/// Section Header Block: it defines the most important characteristics of the capture file.
18#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
19pub struct SectionHeaderBlock<'a> {
20    /// Endianness of the section.
21    pub endianness: Endianness,
22
23    /// Major version of the format.
24    /// Current value is 1.
25    pub major_version: u16,
26
27    /// Minor version of the format.
28    /// Current value is 0.
29    pub minor_version: u16,
30
31    /// Length in bytes of the following section excluding this block.
32    ///
33    /// This block can be used to skip the section for faster navigation in
34    /// large files. Length of -1i64 means that the length is unspecified.
35    pub section_length: i64,
36
37    /// Options
38    pub options: Vec<SectionHeaderOption<'a>>,
39}
40
41impl<'a> PcapNgBlock<'a> for SectionHeaderBlock<'a> {
42    fn from_slice<B: ByteOrder>(mut slice: &'a [u8]) -> Result<(&'a [u8], Self), PcapError> {
43        if slice.len() < 16 {
44            return Err(PcapError::InvalidField("SectionHeaderBlock: block length < 16"));
45        }
46
47        let magic = slice.read_u32::<BigEndian>().unwrap();
48        let endianness = match magic {
49            0x1A2B3C4D => Endianness::Big,
50            0x4D3C2B1A => Endianness::Little,
51            _ => return Err(PcapError::InvalidField("SectionHeaderBlock: invalid magic number")),
52        };
53
54        let (rem, major_version, minor_version, section_length, options) = match endianness {
55            Endianness::Big => parse_inner::<BigEndian>(slice)?,
56            Endianness::Little => parse_inner::<LittleEndian>(slice)?,
57        };
58
59        let block = SectionHeaderBlock { endianness, major_version, minor_version, section_length, options };
60
61        return Ok((rem, block));
62
63        #[allow(clippy::type_complexity)]
64        fn parse_inner<B: ByteOrder>(mut slice: &[u8]) -> Result<(&[u8], u16, u16, i64, Vec<SectionHeaderOption>), PcapError> {
65            let maj_ver = slice.read_u16::<B>().unwrap();
66            let min_ver = slice.read_u16::<B>().unwrap();
67            let sec_len = slice.read_i64::<B>().unwrap();
68            let (rem, opts) = SectionHeaderOption::opts_from_slice::<B>(slice)?;
69
70            Ok((rem, maj_ver, min_ver, sec_len, opts))
71        }
72    }
73
74    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
75        match self.endianness {
76            Endianness::Big => writer.write_u32::<BigEndian>(0x1A2B3C4D)?,
77            Endianness::Little => writer.write_u32::<LittleEndian>(0x1A2B3C4D)?,
78        };
79
80        writer.write_u16::<B>(self.major_version)?;
81        writer.write_u16::<B>(self.minor_version)?;
82        writer.write_i64::<B>(self.section_length)?;
83
84        let opt_len = SectionHeaderOption::write_opts_to::<B, W>(&self.options, writer)?;
85
86        Ok(16 + opt_len)
87    }
88
89    fn into_block(self) -> Block<'a> {
90        Block::SectionHeader(self)
91    }
92}
93
94impl Default for SectionHeaderBlock<'static> {
95    fn default() -> Self {
96        Self {
97            endianness: Endianness::Big,
98            major_version: 1,
99            minor_version: 0,
100            section_length: -1,
101            options: vec![],
102        }
103    }
104}
105
106
107/// Section Header Block options
108#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
109pub enum SectionHeaderOption<'a> {
110    /// Comment associated with the current block
111    Comment(Cow<'a, str>),
112
113    /// Description of the hardware used to create this section
114    Hardware(Cow<'a, str>),
115
116    /// Name of the operating system used to create this section
117    OS(Cow<'a, str>),
118
119    /// Name of the application used to create this section
120    UserApplication(Cow<'a, str>),
121
122    /// Custom option containing binary octets in the Custom Data portion
123    CustomBinary(CustomBinaryOption<'a>),
124
125    /// Custom option containing a UTF-8 string in the Custom Data portion
126    CustomUtf8(CustomUtf8Option<'a>),
127
128    /// Unknown option
129    Unknown(UnknownOption<'a>),
130}
131
132impl<'a> PcapNgOption<'a> for SectionHeaderOption<'a> {
133    fn from_slice<B: ByteOrder>(code: u16, length: u16, slice: &'a [u8]) -> Result<Self, PcapError> {
134        let opt = match code {
135            1 => SectionHeaderOption::Comment(Cow::Borrowed(std::str::from_utf8(slice)?)),
136            2 => SectionHeaderOption::Hardware(Cow::Borrowed(std::str::from_utf8(slice)?)),
137            3 => SectionHeaderOption::OS(Cow::Borrowed(std::str::from_utf8(slice)?)),
138            4 => SectionHeaderOption::UserApplication(Cow::Borrowed(std::str::from_utf8(slice)?)),
139
140            2988 | 19372 => SectionHeaderOption::CustomUtf8(CustomUtf8Option::from_slice::<B>(code, slice)?),
141            2989 | 19373 => SectionHeaderOption::CustomBinary(CustomBinaryOption::from_slice::<B>(code, slice)?),
142
143            _ => SectionHeaderOption::Unknown(UnknownOption::new(code, length, slice)),
144        };
145
146        Ok(opt)
147    }
148
149    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
150        match self {
151            SectionHeaderOption::Comment(a) => a.write_opt_to::<B, W>(1, writer),
152            SectionHeaderOption::Hardware(a) => a.write_opt_to::<B, W>(2, writer),
153            SectionHeaderOption::OS(a) => a.write_opt_to::<B, W>(3, writer),
154            SectionHeaderOption::UserApplication(a) => a.write_opt_to::<B, W>(4, writer),
155            SectionHeaderOption::CustomBinary(a) => a.write_opt_to::<B, W>(a.code, writer),
156            SectionHeaderOption::CustomUtf8(a) => a.write_opt_to::<B, W>(a.code, writer),
157            SectionHeaderOption::Unknown(a) => a.write_opt_to::<B, W>(a.code, writer),
158        }
159    }
160}
pcap_file/pcapng/blocks/section_header.rs

pcap_file/pcapng/blocks/
section_header.rs
