nlink 0.24.0

Async netlink library for Linux network configuration
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

//! Bridge multicast database (MDB) wire types and constants.
//!
//! Mirrors the kernel's `struct br_port_msg` / `struct br_mdb_entry`
//! and the `MDBA_*` netlink attribute enums (`linux/if_bridge.h`).

use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};

/// Bridge port message header (`struct br_port_msg`).
///
/// The C struct is `{ __u8 family; __u32 ifindex; }`; the compiler
/// pads `family` out to the `__u32` alignment, so the on-wire size is
/// 8 bytes with `ifindex` at offset 4. The explicit padding field
/// reproduces that layout for zerocopy.
#[repr(C)]
#[derive(Debug, Clone, Copy, Default, FromBytes, IntoBytes, Immutable, KnownLayout)]
pub struct BrPortMsg {
    /// Address family (always `AF_BRIDGE`).
    pub family: u8,
    /// Padding to align `ifindex`.
    pub pad: [u8; 3],
    /// Bridge interface index (0 in a dump request = all bridges).
    pub ifindex: u32,
}

impl BrPortMsg {
    /// Size of this structure on the wire.
    pub const SIZE: usize = std::mem::size_of::<Self>();

    /// Create a new bridge-port message.
    pub fn new() -> Self {
        Self::default()
    }

    /// Set the address family.
    pub fn with_family(mut self, family: u8) -> Self {
        self.family = family;
        self
    }

    /// Set the bridge interface index.
    pub fn with_ifindex(mut self, ifindex: u32) -> Self {
        self.ifindex = ifindex;
        self
    }
}

/// Bridge MDB entry (`struct br_mdb_entry`).
///
/// The kernel struct embeds an anonymous `addr` sub-struct holding a
/// 16-byte union (`ip4` / `ip6` / `mac_addr`) followed by a `__be16
/// proto`. We flatten the union into a fixed 16-byte `addr` field
/// (large enough for an IPv6 group) plus the `proto` discriminator;
/// the trailing 2 bytes of explicit padding reproduce the C struct's
/// 28-byte size.
#[repr(C)]
#[derive(Debug, Clone, Copy, Default, FromBytes, IntoBytes, Immutable, KnownLayout)]
pub struct BrMdbEntry {
    /// Port interface index this group is programmed on.
    pub ifindex: u32,
    /// Entry state (`MDB_TEMPORARY` / `MDB_PERMANENT`).
    pub state: u8,
    /// Entry flags (`MDB_FLAGS_*`).
    pub flags: u8,
    /// VLAN ID (0 = no VLAN).
    pub vid: u16,
    /// Group address union: IPv4 in the first 4 bytes, IPv6 across
    /// all 16, or a multicast MAC in the first 6.
    pub addr: [u8; 16],
    /// Address protocol (`ETH_P_IP` / `ETH_P_IPV6`, network order;
    /// 0 for an L2 MAC group).
    pub proto: u16,
    /// Padding to the kernel's 28-byte struct size.
    pub _pad: u16,
}

impl BrMdbEntry {
    /// Size of this structure on the wire.
    pub const SIZE: usize = std::mem::size_of::<Self>();
}

// Lock the wire layout to the kernel's struct sizes (if_bridge.h):
// `struct br_port_msg` is 8 bytes (u8 family padded to u32 ifindex),
// `struct br_mdb_entry` is 28 bytes (u32 + u8 + u8 + u16 + 16-byte
// union + __be16 proto + 2 pad).
const _: () = assert!(BrPortMsg::SIZE == 8);
const _: () = assert!(BrMdbEntry::SIZE == 28);

/// Entry state — temporary (ages out).
pub const MDB_TEMPORARY: u8 = 0;
/// Entry state — permanent (static).
pub const MDB_PERMANENT: u8 = 1;

/// Entry flag — programmed in hardware.
pub const MDB_FLAGS_OFFLOAD: u8 = 1 << 0;
/// Entry flag — fast leave.
pub const MDB_FLAGS_FAST_LEAVE: u8 = 1 << 1;
/// Entry flag — (*,G) exclude.
pub const MDB_FLAGS_STAR_EXCL: u8 = 1 << 2;
/// Entry flag — blocked source.
pub const MDB_FLAGS_BLOCKED: u8 = 1 << 3;

/// Top-level MDB attributes (`MDBA_*`).
pub mod mdba {
    /// Nested list of MDB groups.
    pub const MDBA_MDB: u16 = 1;
    /// Nested list of multicast routers.
    pub const MDBA_ROUTER: u16 = 2;
}

/// Attributes nested under `MDBA_MDB` (`MDBA_MDB_*`).
pub mod mdba_mdb {
    /// One group's entry list.
    pub const MDBA_MDB_ENTRY: u16 = 1;
}

/// Attributes nested under `MDBA_MDB_ENTRY` (`MDBA_MDB_ENTRY_*`).
pub mod mdba_mdb_entry {
    /// A `struct br_mdb_entry` payload.
    pub const MDBA_MDB_ENTRY_INFO: u16 = 1;
}

/// Attributes for the add/del request body (`MDBA_SET_ENTRY*`).
pub mod mdba_set {
    /// A `struct br_mdb_entry` to add or delete.
    pub const MDBA_SET_ENTRY: u16 = 1;
}

/// Ethernet protocol numbers used in the `proto` discriminator
/// (network order is applied at encode time).
pub mod eth_p {
    /// IPv4.
    pub const ETH_P_IP: u16 = 0x0800;
    /// IPv6.
    pub const ETH_P_IPV6: u16 = 0x86DD;
}