pnet 0.6.0

Cross-platform, low level networking using the Rust programming language.
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

// Copyright (c) 2014, 2015 Robert Clipsham <robert@octarineparrot.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! IPv4 packet abstraction

use packet::ip::IpNextHeaderProtocol;

use pnet_macros_support::types::*;

use std::net::Ipv4Addr;

/// Represents an IPv4 Packet
#[packet]
pub struct Ipv4 {
    version: u4,
    header_length: u4,
    dscp: u6,
    ecn: u2,
    total_length: u16be,
    identification: u16be,
    flags: u3,
    fragment_offset: u13be,
    ttl: u8,
    #[construct_with(u8)]
    next_level_protocol: IpNextHeaderProtocol,
    checksum: u16be,
    #[construct_with(u8, u8, u8, u8)]
    source: Ipv4Addr,
    #[construct_with(u8, u8, u8, u8)]
    destination: Ipv4Addr,
    #[length_fn = "ipv4_options_length"]
    options: Vec<Ipv4Option>,
    #[payload]
    payload: Vec<u8>,
}

/// Calculates the checksum of an IPv4 packet
pub fn checksum(packet: &Ipv4Packet) -> u16be {
    use packet::Packet;

    let len = packet.get_header_length() as usize * 4;
    let mut sum = 0u32;
    let mut i = 0;
    while i < len {
        let word = (packet.packet()[i] as u32) << 8 | packet.packet()[i + 1] as u32;
        sum = sum + word;
        i = i + 2;
    }
    while sum >> 16 != 0 {
        sum = (sum >> 16) + (sum & 0xFFFF);
    }

    !sum as u16
}

fn ipv4_options_length(ipv4: &Ipv4Packet) -> usize {
    ipv4.get_header_length() as usize - 5
}

#[test]
fn ipv4_options_length_test() {
    let mut packet = [0u8; 20];
    let mut ip_header = MutableIpv4Packet::new(&mut packet[..]).unwrap();
    ip_header.set_header_length(5);
    assert_eq!(ipv4_options_length(&ip_header.to_immutable()), 0);
}

/// Represents the IPv4 Option field
#[packet]
pub struct Ipv4Option {
    copied: u1,
    class: u2,
    number: u5,
    length: u8,
    #[payload]
    data: Vec<u8>,
}

#[test]
fn ipv4_packet_test() {
    use packet::ip::IpNextHeaderProtocols;

    let mut packet = [0u8; 20];
    {
        let mut ip_header = MutableIpv4Packet::new(&mut packet[..]).unwrap();
        ip_header.set_version(4);
        assert_eq!(ip_header.get_version(), 4);

        ip_header.set_header_length(5);
        assert_eq!(ip_header.get_header_length(), 5);

        ip_header.set_dscp(4);
        assert_eq!(ip_header.get_dscp(), 4);

        ip_header.set_ecn(1);
        assert_eq!(ip_header.get_ecn(), 1);

        ip_header.set_total_length(115);
        assert_eq!(ip_header.get_total_length(), 115);

        ip_header.set_identification(257);
        assert_eq!(ip_header.get_identification(), 257);

        ip_header.set_flags(2);
        assert_eq!(ip_header.get_flags(), 2);

        ip_header.set_fragment_offset(257);
        assert_eq!(ip_header.get_fragment_offset(), 257);

        ip_header.set_ttl(64);
        assert_eq!(ip_header.get_ttl(), 64);

        ip_header.set_next_level_protocol(IpNextHeaderProtocols::Udp);
        assert_eq!(ip_header.get_next_level_protocol(),
                   IpNextHeaderProtocols::Udp);

        ip_header.set_source(Ipv4Addr::new(192, 168, 0, 1));
        assert_eq!(ip_header.get_source(), Ipv4Addr::new(192, 168, 0, 1));

        ip_header.set_destination(Ipv4Addr::new(192, 168, 0, 199));
        assert_eq!(ip_header.get_destination(), Ipv4Addr::new(192, 168, 0, 199));

        let imm_header = checksum(&ip_header.to_immutable());
        ip_header.set_checksum(imm_header);
        assert_eq!(ip_header.get_checksum(), 0xb64e);
    }

    let ref_packet = [0x45,           /* ver/ihl */
                      0x11,           /* dscp/ecn */
                      0x00, 0x73,     /* total len */
                      0x01, 0x01,     /* identification */
                      0x41, 0x01,     /* flags/frag offset */
                      0x40,           /* ttl */
                      0x11,           /* proto */
                      0xb6, 0x4e,     /* checksum */
                      0xc0, 0xa8, 0x00, 0x01, /* source ip */
                      0xc0, 0xa8, 0x00, 0xc7  /* dest ip */];

    assert_eq!(&ref_packet[..], &packet[..]);
}