pcaparse 0.2.0

A crate to parse, read and write Cap(NA Sniffer 2.x), 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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254

//! Packet Block.

use std::borrow::Cow;
use std::io::Result as IoResult;
use std::io::Write;

use byteorder::{ReadBytesExt, WriteBytesExt};
use derive_into_owned::IntoOwned;

use byteorder::ByteOrder;
#[cfg(feature = "tokio")]
use tokio::io::AsyncWrite;
#[cfg(feature = "tokio")]
use tokio_byteorder::{AsyncReadBytesExt, AsyncWriteBytesExt};

#[cfg(feature = "tokio")]
use super::block_common::AsyncPcapNgBlock;
use super::block_common::{Block, PcapNgBlock};
#[cfg(feature = "tokio")]
use super::opt_common::{AsyncPcapNgOption, AsyncWriteOptTo};
use super::opt_common::{CustomBinaryOption, CustomUtf8Option, PcapNgOption, UnknownOption, WriteOptTo};
use crate::errors::PcapError;

/// The Packet Block is obsolete, and MUST NOT be used in new files.
/// Use the Enhanced Packet Block or Simple Packet Block instead.
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub struct PacketBlock<'a> {
    /// It specifies the interface this packet comes from.
    pub interface_id: u16,

    /// Local drop counter.
    ///
    /// It specifies the number of packets lost (by the interface and the operating system)
    /// between this packet and the preceding one.
    pub drop_count: u16,

    /// The timestamp is a single 64-bit unsigned integer that represents the number of units of time
    /// that have elapsed since 1970-01-01 00:00:00 UTC.
    pub timestamp: u64,

    /// Number of octets captured from the packet (i.e. the length of the Packet Data field).
    pub captured_len: u32,

    /// Actual length of the packet when it was transmitted on the network.
    pub original_len: u32,

    /// The data coming from the network, including link-layer headers.
    pub data: Cow<'a, [u8]>,

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

impl<'a> PcapNgBlock<'a> for PacketBlock<'a> {
    fn from_slice<B: ByteOrder>(mut slice: &'a [u8]) -> Result<(&'a [u8], Self), PcapError> {
        if slice.len() < 20 {
            return Err(PcapError::InvalidField("EnhancedPacketBlock: block length length < 20"));
        }

        let interface_id = ReadBytesExt::read_u16::<B>(&mut slice).unwrap();
        let drop_count = ReadBytesExt::read_u16::<B>(&mut slice).unwrap();
        let timestamp = ReadBytesExt::read_u64::<B>(&mut slice).unwrap();
        let captured_len = ReadBytesExt::read_u32::<B>(&mut slice).unwrap();
        let original_len = ReadBytesExt::read_u32::<B>(&mut slice).unwrap();

        let pad_len = (4 - (captured_len as usize % 4)) % 4;
        let tot_len = captured_len as usize + pad_len;

        if slice.len() < tot_len {
            return Err(PcapError::InvalidField("EnhancedPacketBlock: captured_len + padding > block length"));
        }

        let data = &slice[..captured_len as usize];
        slice = &slice[tot_len..];

        let (slice, options) = PacketOption::opts_from_slice::<B>(slice)?;
        let block = PacketBlock {
            interface_id,
            drop_count,
            timestamp,
            captured_len,
            original_len,
            data: Cow::Borrowed(data),
            options,
        };

        Ok((slice, block))
    }

    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
        writer.write_u16::<B>(self.interface_id)?;
        writer.write_u16::<B>(self.drop_count)?;
        writer.write_u64::<B>(self.timestamp)?;
        writer.write_u32::<B>(self.captured_len)?;
        writer.write_u32::<B>(self.original_len)?;
        writer.write_all(&self.data)?;

        let pad_len = (4 - (self.captured_len as usize % 4)) % 4;
        writer.write_all(&[0_u8; 3][..pad_len])?;

        let opt_len = PacketOption::write_opts_to::<B, _>(&self.options, writer)?;

        Ok(20 + self.data.len() + pad_len + opt_len)
    }

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

#[cfg(feature = "tokio")]
#[async_trait::async_trait]
impl<'a> AsyncPcapNgBlock<'a> for PacketBlock<'a> {
    async fn async_from_slice<B: ByteOrder + Send>(mut slice: &'a [u8]) -> Result<(&'a [u8], PacketBlock<'a>), PcapError> {
        if slice.len() < 20 {
            return Err(PcapError::InvalidField("EnhancedPacketBlock: block length length < 20"));
        }

        let interface_id = AsyncReadBytesExt::read_u16::<B>(&mut slice).await.unwrap();
        let drop_count = AsyncReadBytesExt::read_u16::<B>(&mut slice).await.unwrap();
        let timestamp = AsyncReadBytesExt::read_u64::<B>(&mut slice).await.unwrap();
        let captured_len = AsyncReadBytesExt::read_u32::<B>(&mut slice).await.unwrap();
        let original_len = AsyncReadBytesExt::read_u32::<B>(&mut slice).await.unwrap();

        let pad_len = (4 - (captured_len as usize % 4)) % 4;
        let tot_len = captured_len as usize + pad_len;

        if slice.len() < tot_len {
            return Err(PcapError::InvalidField("EnhancedPacketBlock: captured_len + padding > block length"));
        }

        let data = &slice[..captured_len as usize];
        slice = &slice[tot_len..];

        let (slice, options) = PacketOption::async_opts_from_slice::<B>(slice).await?;
        let block = PacketBlock {
            interface_id,
            drop_count,
            timestamp,
            captured_len,
            original_len,
            data: Cow::Borrowed(data),
            options,
        };

        Ok((slice, block))
    }

    async fn async_write_to<B: ByteOrder, W: AsyncWrite + Unpin + Send>(&self, writer: &mut W) -> IoResult<usize> {
        writer.write_u16::<B>(self.interface_id).await?;
        writer.write_u16::<B>(self.drop_count).await?;
        writer.write_u64::<B>(self.timestamp).await?;
        writer.write_u32::<B>(self.captured_len).await?;
        writer.write_u32::<B>(self.original_len).await?;
        tokio::io::AsyncWriteExt::write_all(writer, &self.data).await?;

        let pad_len = (4 - (self.captured_len as usize % 4)) % 4;
        tokio::io::AsyncWriteExt::write_all(writer, &[0_u8; 3][..pad_len]).await?;

        let opt_len = PacketOption::async_write_opts_to::<B, _>(&self.options, writer).await?;

        Ok(20 + self.data.len() + pad_len + opt_len)
    }
}

/// Packet Block option
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub enum PacketOption<'a> {
    /// Comment associated with the current block
    Comment(Cow<'a, str>),

    /// 32-bit flags word containing link-layer information.
    Flags(u32),

    /// Contains a hash of the packet.
    Hash(Cow<'a, [u8]>),

    /// Custom option containing binary octets in the Custom Data portion
    CustomBinary(CustomBinaryOption<'a>),

    /// Custom option containing a UTF-8 string in the Custom Data portion
    CustomUtf8(CustomUtf8Option<'a>),

    /// Unknown option
    Unknown(UnknownOption<'a>),
}

impl<'a> PcapNgOption<'a> for PacketOption<'a> {
    fn from_slice<B: ByteOrder>(code: u16, length: u16, mut slice: &'a [u8]) -> Result<Self, PcapError> {
        let opt = match code {
            1 => PacketOption::Comment(Cow::Borrowed(std::str::from_utf8(slice)?)),
            2 => {
                if slice.len() != 4 {
                    return Err(PcapError::InvalidField("PacketOption: Flags length != 4"));
                }
                PacketOption::Flags(ReadBytesExt::read_u32::<B>(&mut slice).map_err(|_| PcapError::IncompleteBuffer)?)
            },
            3 => PacketOption::Hash(Cow::Borrowed(slice)),

            2988 | 19372 => PacketOption::CustomUtf8(CustomUtf8Option::from_slice::<B>(code, slice)?),
            2989 | 19373 => PacketOption::CustomBinary(CustomBinaryOption::from_slice::<B>(code, slice)?),

            _ => PacketOption::Unknown(UnknownOption::new(code, length, slice)),
        };

        Ok(opt)
    }

    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
        match self {
            PacketOption::Comment(a) => a.write_opt_to::<B, W>(1, writer),
            PacketOption::Flags(a) => a.write_opt_to::<B, W>(2, writer),
            PacketOption::Hash(a) => a.write_opt_to::<B, W>(3, writer),
            PacketOption::CustomBinary(a) => a.write_opt_to::<B, W>(a.code, writer),
            PacketOption::CustomUtf8(a) => a.write_opt_to::<B, W>(a.code, writer),
            PacketOption::Unknown(a) => a.write_opt_to::<B, W>(a.code, writer),
        }
    }
}

#[cfg(feature = "tokio")]
#[async_trait::async_trait]
impl<'a> AsyncPcapNgOption<'a> for PacketOption<'a> {
    async fn async_from_slice<B: ByteOrder + Send>(code: u16, length: u16, mut slice: &'a [u8]) -> Result<PacketOption<'a>, PcapError> {
        let opt = match code {
            1 => PacketOption::Comment(Cow::Borrowed(std::str::from_utf8(slice)?)),
            2 => {
                if slice.len() != 4 {
                    return Err(PcapError::InvalidField("PacketOption: Flags length != 4"));
                }
                PacketOption::Flags(AsyncReadBytesExt::read_u32::<B>(&mut slice).await.map_err(|_| PcapError::IncompleteBuffer)?)
            },
            3 => PacketOption::Hash(Cow::Borrowed(slice)),

            2988 | 19372 => PacketOption::CustomUtf8(CustomUtf8Option::async_from_slice::<B>(code, slice).await?),
            2989 | 19373 => PacketOption::CustomBinary(CustomBinaryOption::async_from_slice::<B>(code, slice).await?),

            _ => PacketOption::Unknown(UnknownOption::new(code, length, slice)),
        };

        Ok(opt)
    }

    async fn async_write_to<B: ByteOrder, W: AsyncWrite + Unpin + Send>(&self, writer: &mut W) -> IoResult<usize> {
        match self {
            PacketOption::Comment(a) => a.async_write_opt_to::<B, W>(1, writer).await,
            PacketOption::Flags(a) => a.async_write_opt_to::<B, W>(2, writer).await,
            PacketOption::Hash(a) => a.async_write_opt_to::<B, W>(3, writer).await,
            PacketOption::CustomBinary(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
            PacketOption::CustomUtf8(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
            PacketOption::Unknown(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
        }
    }
}