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

use crate::pcapng::blocks::opts_from_slice;
use crate::errors::PcapError;
use byteorder::{ByteOrder, ReadBytesExt};
use crate::pcapng::{CustomUtf8Option, CustomBinaryOption, UnknownOption};
use std::borrow::Cow;
use derive_into_owned::IntoOwned;


/// The Packet Block is obsolete, and MUST NOT be used in new files.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)]
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> PacketBlock<'a> {

    pub 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 = slice.read_u16::<B>()?;
        let drop_count = slice.read_u16::<B>()?;
        let timestamp = slice.read_u64::<B>()?;
        let captured_len = slice.read_u32::<B>()?;
        let original_len = slice.read_u32::<B>()?;

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

        Ok((slice, block))
    }
}

#[derive(Clone, Debug, IntoOwned)]
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> PacketOption<'a> {

    pub fn from_slice<B:ByteOrder>(slice: &'a [u8]) -> Result<(&'a[u8], Vec<Self>), PcapError> {

        opts_from_slice::<B, _, _>(slice, |mut slice, code, length| {

            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(slice.read_u32::<B>()?)
                },
                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)
        })
    }
}