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
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289

//! Enhanced Packet Block (EPB).

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

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;
use crate::DataLink;

/// An Enhanced Packet Block (EPB) is the standard container for storing the packets coming from the network.
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub struct EnhancedPacketBlock<'a> {
    /// It specifies the interface this packet comes from.
    ///
    /// The correct interface will be the one whose Interface Description Block
    /// (within the current Section of the file) is identified by the same number of this field.
    pub interface_id: u32,

    /// Timestamp number stored in data
    pub timestamp_num: u64,

    /// Number of units of time that have elapsed since 1970-01-01 00:00:00 UTC.
    /// Temporarily, the timestamp is calculated in macroseconds as the timeunit.
    pub timestamp: Duration,

    /// Linktype update from IDB, use ethernet as default.
    pub linktype: DataLink,

    /// 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<EnhancedPacketOption<'a>>,
}

impl<'a> PcapNgBlock<'a> for EnhancedPacketBlock<'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_u32::<B>(&mut slice).unwrap();
        let timestamp_high = ReadBytesExt::read_u32::<B>(&mut slice).unwrap() as u64;
        let timestamp_low = ReadBytesExt::read_u32::<B>(&mut slice).unwrap() as u64;
        let timestamp_num = (timestamp_high << 32) + timestamp_low;
        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) = EnhancedPacketOption::opts_from_slice::<B>(slice)?;
        let block = EnhancedPacketBlock {
            interface_id,
            timestamp_num,
            timestamp: Duration::from_micros(timestamp_num),
            linktype: DataLink::ETHERNET,
            original_len,
            data: Cow::Borrowed(data),
            options,
        };

        Ok((slice, block))
    }

    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
        let pad_len = (4 - (&self.data.len() % 4)) % 4;

        writer.write_u32::<B>(self.interface_id)?;

        let timestamp = self.timestamp_num;
        let timestamp_high = (timestamp >> 32) as u32;
        writer.write_u32::<B>(timestamp_high)?;
        let timestamp_low = (timestamp & 0xFFFFFFFF) as u32;
        writer.write_u32::<B>(timestamp_low)?;

        writer.write_u32::<B>(self.data.len() as u32)?;
        writer.write_u32::<B>(self.original_len)?;
        writer.write_all(&self.data)?;
        writer.write_all(&[0_u8; 3][..pad_len])?;

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

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

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

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

        let interface_id = AsyncReadBytesExt::read_u32::<B>(&mut slice).await.unwrap();
        let timestamp_high = AsyncReadBytesExt::read_u32::<B>(&mut slice).await.unwrap() as u64;
        let timestamp_low = AsyncReadBytesExt::read_u32::<B>(&mut slice).await.unwrap() as u64;
        let timestamp_num = (timestamp_high << 32) + timestamp_low;
        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) = EnhancedPacketOption::async_opts_from_slice::<B>(slice).await?;
        let block = EnhancedPacketBlock {
            interface_id,
            timestamp_num,
            timestamp: Duration::from_micros(timestamp_num),
            linktype: DataLink::ETHERNET,
            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> {
        let pad_len = (4 - (&self.data.len() % 4)) % 4;

        writer.write_u32::<B>(self.interface_id).await?;

        let timestamp = self.timestamp_num;
        let timestamp_high = (timestamp >> 32) as u32;
        writer.write_u32::<B>(timestamp_high).await?;
        let timestamp_low = (timestamp & 0xFFFFFFFF) as u32;
        writer.write_u32::<B>(timestamp_low).await?;

        writer.write_u32::<B>(self.data.len() as u32).await?;
        writer.write_u32::<B>(self.original_len).await?;
        tokio::io::AsyncWriteExt::write_all(writer, &self.data).await?;
        tokio::io::AsyncWriteExt::write_all(writer, &[0_u8; 3][..pad_len]).await?;

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

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

/// The Enhanced Packet Block (EPB) options
#[derive(Clone, Debug, IntoOwned, Eq, PartialEq)]
pub enum EnhancedPacketOption<'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]>),

    /// 64-bit integer value specifying the number of packets lost
    /// (by the interface and the operating system) between this packet and the preceding one for
    /// the same interface or, for the first packet for an interface, between this packet
    /// and the start of the capture process.
    DropCount(u64),

    /// 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 EnhancedPacketOption<'a> {
    fn from_slice<B: ByteOrder>(code: u16, length: u16, mut slice: &'a [u8]) -> Result<Self, PcapError> {
        let opt = match code {
            1 => EnhancedPacketOption::Comment(Cow::Borrowed(std::str::from_utf8(slice)?)),
            2 => {
                if slice.len() != 4 {
                    return Err(PcapError::InvalidField("EnhancedPacketOption: Flags length != 4"));
                }
                EnhancedPacketOption::Flags(ReadBytesExt::read_u32::<B>(&mut slice).map_err(|_| PcapError::IncompleteBuffer)?)
            },
            3 => EnhancedPacketOption::Hash(Cow::Borrowed(slice)),
            4 => {
                if slice.len() != 8 {
                    return Err(PcapError::InvalidField("EnhancedPacketOption: DropCount length != 8"));
                }
                EnhancedPacketOption::DropCount(ReadBytesExt::read_u64::<B>(&mut slice).map_err(|_| PcapError::IncompleteBuffer)?)
            },

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

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

        Ok(opt)
    }

    fn write_to<B: ByteOrder, W: Write>(&self, writer: &mut W) -> IoResult<usize> {
        match self {
            EnhancedPacketOption::Comment(a) => a.write_opt_to::<B, W>(1, writer),
            EnhancedPacketOption::Flags(a) => a.write_opt_to::<B, W>(2, writer),
            EnhancedPacketOption::Hash(a) => a.write_opt_to::<B, W>(3, writer),
            EnhancedPacketOption::DropCount(a) => a.write_opt_to::<B, W>(4, writer),
            EnhancedPacketOption::CustomBinary(a) => a.write_opt_to::<B, W>(a.code, writer),
            EnhancedPacketOption::CustomUtf8(a) => a.write_opt_to::<B, W>(a.code, writer),
            EnhancedPacketOption::Unknown(a) => a.write_opt_to::<B, W>(a.code, writer),
        }
    }
}

#[cfg(feature = "tokio")]
#[async_trait::async_trait]
impl<'a> AsyncPcapNgOption<'a> for EnhancedPacketOption<'a> {
    async fn async_from_slice<B: ByteOrder + Send>(code: u16, length: u16, mut slice: &'a [u8]) -> Result<Self, PcapError> {
        let opt = match code {
            1 => EnhancedPacketOption::Comment(Cow::Borrowed(std::str::from_utf8(slice)?)),
            2 => {
                if slice.len() != 4 {
                    return Err(PcapError::InvalidField("EnhancedPacketOption: Flags length != 4"));
                }
                EnhancedPacketOption::Flags(AsyncReadBytesExt::read_u32::<B>(&mut slice).await.map_err(|_| PcapError::IncompleteBuffer)?)
            },
            3 => EnhancedPacketOption::Hash(Cow::Borrowed(slice)),
            4 => {
                if slice.len() != 8 {
                    return Err(PcapError::InvalidField("EnhancedPacketOption: DropCount length != 8"));
                }
                EnhancedPacketOption::DropCount(
                    AsyncReadBytesExt::read_u64::<B>(&mut slice).await.map_err(|_| PcapError::IncompleteBuffer)?,
                )
            },

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

            _ => EnhancedPacketOption::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 {
            EnhancedPacketOption::Comment(a) => a.async_write_opt_to::<B, W>(1, writer).await,
            EnhancedPacketOption::Flags(a) => a.async_write_opt_to::<B, W>(2, writer).await,
            EnhancedPacketOption::Hash(a) => a.async_write_opt_to::<B, W>(3, writer).await,
            EnhancedPacketOption::DropCount(a) => a.async_write_opt_to::<B, W>(4, writer).await,
            EnhancedPacketOption::CustomBinary(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
            EnhancedPacketOption::CustomUtf8(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
            EnhancedPacketOption::Unknown(a) => a.async_write_opt_to::<B, W>(a.code, writer).await,
        }
    }
}