link: use struct BridgeId instead of tuple and fix its endianess

The bridge ID defined by attributes BRIDGE_ID and ROOT_ID, both in
bridge and bridge_port, contains a priority field and the MAC address.
Use a named struct to show the meaning of these fields instead of using
a tuple.

Also, fix the endianess of the priority field. The kernel uses a
`u8 prio[2]` field instead of `u16`, with the first byte being the
highest order byte. See: https://elixir.bootlin.com/linux/v6.6.9/source/net/bridge/br_netlink.c#L1633

Note: to make the file bridge.rs to be well organized, moved the
definition of BRIDGE_QUERIER_* close to BridgeQuerierState where it's
used.

Signed-off-by: Íñigo Huguet <[email protected]>

Author: ihuguet

src/link/link_info/bridge.rs

@@ -14,14 +14,6 @@ use netlink_packet_utils::{
     DecodeError,
 };
 
-const BRIDGE_QUERIER_IP_ADDRESS: u16 = 1;
-const BRIDGE_QUERIER_IP_PORT: u16 = 2;
-const BRIDGE_QUERIER_IP_OTHER_TIMER: u16 = 3;
-// const BRIDGE_QUERIER_PAD: u16 = 4;
-const BRIDGE_QUERIER_IPV6_ADDRESS: u16 = 5;
-const BRIDGE_QUERIER_IPV6_PORT: u16 = 6;
-const BRIDGE_QUERIER_IPV6_OTHER_TIMER: u16 = 7;
-
 const IFLA_BR_FORWARD_DELAY: u16 = 1;
 const IFLA_BR_HELLO_TIME: u16 = 2;
 const IFLA_BR_MAX_AGE: u16 = 3;
@@ -98,8 +90,8 @@ pub enum InfoBridge {
     Priority(u16),
     VlanProtocol(u16),
     GroupFwdMask(u16),
-    RootId((u16, [u8; 6])),
-    BridgeId((u16, [u8; 6])),
+    RootId(BridgeId),
+    BridgeId(BridgeId),
     RootPort(u16),
     VlanDefaultPvid(u16),
     VlanFiltering(u8),
@@ -219,10 +211,8 @@ impl Nla for InfoBridge {
 
             Self::VlanProtocol(value) => BigEndian::write_u16(buffer, *value),
 
-            Self::RootId((priority, ref address))
-            | Self::BridgeId((priority, ref address)) => {
-                NativeEndian::write_u16(buffer, *priority);
-                buffer[2..].copy_from_slice(&address[..]);
+            Self::RootId(bridge_id) | Self::BridgeId(bridge_id) => {
+                bridge_id.emit(buffer)
             }
 
             Self::GroupAddr(value) => buffer.copy_from_slice(&value[..]),
@@ -423,25 +413,14 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>> for InfoBridge {
                 parse_u16(payload)
                     .context("invalid IFLA_BR_GROUP_FWD_MASK value")?,
             ),
-            IFLA_BR_ROOT_ID | IFLA_BR_BRIDGE_ID => {
-                if payload.len() != 8 {
-                    return Err(
-                        "invalid IFLA_BR_ROOT_ID or IFLA_BR_BRIDGE_ID value"
-                            .into(),
-                    );
-                }
-
-                let priority = NativeEndian::read_u16(&payload[..2]);
-                let address = parse_mac(&payload[2..]).context(
-                    "invalid IFLA_BR_ROOT_ID or IFLA_BR_BRIDGE_ID value",
-                )?;
-
-                match buf.kind() {
-                    IFLA_BR_ROOT_ID => Self::RootId((priority, address)),
-                    IFLA_BR_BRIDGE_ID => Self::BridgeId((priority, address)),
-                    _ => unreachable!(),
-                }
-            }
+            IFLA_BR_ROOT_ID => Self::RootId(
+                BridgeId::parse(&BridgeIdBuffer::new(payload))
+                    .context("invalid IFLA_BR_ROOT_ID value")?,
+            ),
+            IFLA_BR_BRIDGE_ID => Self::BridgeId(
+                BridgeId::parse(&BridgeIdBuffer::new(payload))
+                    .context("invalid IFLA_BR_BRIDGE_ID value")?,
+            ),
             IFLA_BR_GROUP_ADDR => Self::GroupAddr(
                 parse_mac(payload)
                     .context("invalid IFLA_BR_GROUP_ADDR value")?,
@@ -536,6 +515,52 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>> for InfoBridge {
     }
 }
 
+const BRIDGE_ID_LEN: usize = 8;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct BridgeId {
+    pub priority: u16,
+    pub address: [u8; 6],
+}
+
+buffer!(BridgeIdBuffer(BRIDGE_ID_LEN) {
+    priority: (u16, 0..2),
+    address: (slice, 2..BRIDGE_ID_LEN)
+});
+
+impl<T: AsRef<[u8]> + ?Sized> Parseable<BridgeIdBuffer<&T>> for BridgeId {
+    fn parse(buf: &BridgeIdBuffer<&T>) -> Result<Self, DecodeError> {
+        // Priority is encoded in big endian. From kernel's
+        // net/bridge/br_netlink.c br_fill_info():
+        // u16 priority = (br->bridge_id.prio[0] << 8) | br->bridge_id.prio[1];
+        Ok(Self {
+            priority: u16::from_be(buf.priority()),
+            address: parse_mac(buf.address())
+                .context("invalid MAC address in BridgeId buffer")?,
+        })
+    }
+}
+
+impl Emitable for BridgeId {
+    fn buffer_len(&self) -> usize {
+        BRIDGE_ID_LEN
+    }
+
+    fn emit(&self, buffer: &mut [u8]) {
+        let mut buffer = BridgeIdBuffer::new(buffer);
+        buffer.set_priority(self.priority.to_be());
+        buffer.address_mut().copy_from_slice(&self.address[..]);
+    }
+}
+
+const BRIDGE_QUERIER_IP_ADDRESS: u16 = 1;
+const BRIDGE_QUERIER_IP_PORT: u16 = 2;
+const BRIDGE_QUERIER_IP_OTHER_TIMER: u16 = 3;
+// const BRIDGE_QUERIER_PAD: u16 = 4;
+const BRIDGE_QUERIER_IPV6_ADDRESS: u16 = 5;
+const BRIDGE_QUERIER_IPV6_PORT: u16 = 6;
+const BRIDGE_QUERIER_IPV6_OTHER_TIMER: u16 = 7;
+
 #[derive(Debug, Clone, Eq, PartialEq)]
 #[non_exhaustive]
 pub enum BridgeQuerierState {

src/link/link_info/bridge_port.rs

@@ -1,10 +1,11 @@
 // SPDX-License-Identifier: MIT
+use crate::link::{BridgeId, BridgeIdBuffer};
 use anyhow::Context;
 use byteorder::{ByteOrder, NativeEndian};
 use netlink_packet_utils::{
     nla::{DefaultNla, Nla, NlaBuffer},
-    parsers::{parse_mac, parse_u16, parse_u32, parse_u64, parse_u8},
-    traits::Parseable,
+    parsers::{parse_u16, parse_u32, parse_u64, parse_u8},
+    traits::{Emitable, Parseable},
     DecodeError,
 };
 
@@ -68,8 +69,8 @@ pub enum InfoBridgePort {
     UnicastFlood(bool),
     ProxyARP(bool),
     ProxyARPWifi(bool),
-    RootId((u16, [u8; 6])),
-    BridgeId((u16, [u8; 6])),
+    RootId(BridgeId),
+    BridgeId(BridgeId),
     DesignatedPort(u16),
     DesignatedCost(u16),
     PortId(u16),
@@ -199,11 +200,8 @@ impl Nla for InfoBridgePort {
             | InfoBridgePort::HoldTimer(value) => {
                 NativeEndian::write_u64(buffer, *value)
             }
-            InfoBridgePort::RootId((prio, addr))
-            | InfoBridgePort::BridgeId((prio, addr)) => {
-                NativeEndian::write_u16(buffer, *prio);
-                buffer[2..].copy_from_slice(&addr[..]);
-            }
+            InfoBridgePort::RootId(bridge_id)
+            | InfoBridgePort::BridgeId(bridge_id) => bridge_id.emit(buffer),
             InfoBridgePort::State(state) => buffer[0] = (*state).into(),
             InfoBridgePort::MulticastRouter(mcast_router) => {
                 buffer[0] = (*mcast_router).into()
@@ -339,32 +337,16 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>>
                     format!("invalid IFLA_BRPORT_PROXYARP_WIFI {payload:?}")
                 })? > 0,
             ),
-            IFLA_BRPORT_ROOT_ID => {
-                if payload.len() != 8 {
-                    return Err(format!(
-                        "invalid IFLA_BRPORT_ROOT_ID {payload:?}"
-                    )
-                    .into());
-                }
-                let prio = NativeEndian::read_u16(&payload[0..2]);
-                let addr = parse_mac(&payload[2..]).with_context(|| {
+            IFLA_BRPORT_ROOT_ID => Self::RootId(
+                BridgeId::parse(&BridgeIdBuffer::new(payload)).with_context(|| {
                     format!("invalid IFLA_BRPORT_ROOT_ID {payload:?}")
-                })?;
-                InfoBridgePort::RootId((prio, addr))
-            }
-            IFLA_BRPORT_BRIDGE_ID => {
-                if payload.len() != 8 {
-                    return Err(format!(
-                        "invalid IFLA_BRPORT_BRIDGE_ID {payload:?}"
-                    )
-                    .into());
-                }
-                let prio = NativeEndian::read_u16(&payload[0..2]);
-                let addr = parse_mac(&payload[2..]).with_context(|| {
+                })?,
+            ),
+            IFLA_BRPORT_BRIDGE_ID => Self::BridgeId(
+                BridgeId::parse(&BridgeIdBuffer::new(payload)).with_context(|| {
                     format!("invalid IFLA_BRPORT_BRIDGE_ID {payload:?}")
-                })?;
-                InfoBridgePort::BridgeId((prio, addr))
-            }
+                })?,
+            ),
             IFLA_BRPORT_DESIGNATED_PORT => InfoBridgePort::DesignatedPort(
                 parse_u16(payload).with_context(|| {
                     format!("invalid IFLA_BRPORT_DESIGNATED_PORT {payload:?}")

src/link/link_info/mod.rs

@@ -29,7 +29,9 @@ mod xstats;
 
 pub use self::bond::{BondAdInfo, InfoBond};
 pub use self::bond_port::{BondPortState, InfoBondPort, MiiStatus};
-pub use self::bridge::{BridgeQuerierState, InfoBridge};
+pub use self::bridge::{
+    BridgeId, BridgeIdBuffer, BridgeQuerierState, InfoBridge,
+};
 pub use self::bridge_port::{
     BridgePortMulticastRouter, BridgePortState, InfoBridgePort,
 };

src/link/mod.rs

@@ -38,12 +38,13 @@ pub use self::ext_mask::LinkExtentMask;
 pub use self::header::{LinkHeader, LinkMessageBuffer};
 pub use self::link_flag::LinkFlag;
 pub use self::link_info::{
-    BondAdInfo, BondPortState, BridgePortMulticastRouter, BridgePortState,
-    BridgeQuerierState, HsrProtocol, InfoBond, InfoBondPort, InfoBridge,
-    InfoBridgePort, InfoData, InfoGreTap, InfoGreTap6, InfoGreTun, InfoGreTun6,
-    InfoGtp, InfoHsr, InfoIpVlan, InfoIpoib, InfoKind, InfoMacSec, InfoMacVlan,
-    InfoMacVtap, InfoPortData, InfoPortKind, InfoSitTun, InfoTun, InfoVeth,
-    InfoVlan, InfoVrf, InfoVti, InfoVxlan, InfoXfrm, LinkInfo, LinkXstats,
+    BondAdInfo, BondPortState, BridgeId, BridgeIdBuffer,
+    BridgePortMulticastRouter, BridgePortState, BridgeQuerierState,
+    HsrProtocol, InfoBond, InfoBondPort, InfoBridge, InfoBridgePort, InfoData,
+    InfoGreTap, InfoGreTap6, InfoGreTun, InfoGreTun6, InfoGtp, InfoHsr,
+    InfoIpVlan, InfoIpoib, InfoKind, InfoMacSec, InfoMacVlan, InfoMacVtap,
+    InfoPortData, InfoPortKind, InfoSitTun, InfoTun, InfoVeth, InfoVlan,
+    InfoVrf, InfoVti, InfoVxlan, InfoXfrm, LinkInfo, LinkXstats,
     MacSecCipherId, MacSecOffload, MacSecValidate, MiiStatus, VlanQosMapping,
 };
 pub use self::link_layer_type::LinkLayerType;

src/link/tests/bridge.rs

@@ -7,11 +7,12 @@ use netlink_packet_utils::{
 
 use crate::link::{
     af_spec::VecAfSpecBridge, AfSpecBridge, AfSpecInet, AfSpecInet6,
-    AfSpecUnspec, BridgePortMulticastRouter, BridgePortState, BridgeVlanInfo,
-    Inet6CacheInfo, Inet6DevConf, Inet6IfaceFlag, Inet6IfaceFlags, InetDevConf,
-    InfoBridge, InfoBridgePort, InfoData, InfoKind, InfoPortData, InfoPortKind,
-    LinkAttribute, LinkFlag, LinkHeader, LinkInfo, LinkLayerType, LinkMessage,
-    LinkMessageBuffer, LinkXdp, Map, State, Stats, Stats64, XdpAttached,
+    AfSpecUnspec, BridgeId, BridgePortMulticastRouter, BridgePortState,
+    BridgeVlanInfo, Inet6CacheInfo, Inet6DevConf, Inet6IfaceFlag,
+    Inet6IfaceFlags, InetDevConf, InfoBridge, InfoBridgePort, InfoData,
+    InfoKind, InfoPortData, InfoPortKind, LinkAttribute, LinkFlag, LinkHeader,
+    LinkInfo, LinkLayerType, LinkMessage, LinkMessageBuffer, LinkXdp, Map,
+    State, Stats, Stats64, XdpAttached,
 };
 use crate::AddressFamily;
 
@@ -260,14 +261,14 @@ fn test_parse_link_bridge_no_extention_mask() {
                     InfoBridge::Priority(32768),
                     InfoBridge::VlanFiltering(0),
                     InfoBridge::GroupFwdMask(0),
-                    InfoBridge::BridgeId((
-                        0x0080, // iproute is showing it as 0x8000
-                        [0x00, 0x23, 0x45, 0x67, 0x89, 0x1c],
-                    )),
-                    InfoBridge::RootId((
-                        0x0080, // iproute is showing it as 0x8000
-                        [0x00, 0x23, 0x45, 0x67, 0x89, 0x1c],
-                    )),
+                    InfoBridge::BridgeId(BridgeId {
+                        priority: 0x8000,
+                        address: [0x00, 0x23, 0x45, 0x67, 0x89, 0x1c],
+                    }),
+                    InfoBridge::RootId(BridgeId {
+                        priority: 0x8000,
+                        address: [0x00, 0x23, 0x45, 0x67, 0x89, 0x1c],
+                    }),
                     InfoBridge::RootPort(0),
                     InfoBridge::RootPathCost(0),
                     InfoBridge::TopologyChange(0),
@@ -513,14 +514,14 @@ fn test_bridge_port_link_info() {
                 InfoBridgePort::BroadcastFlood(true),
                 InfoBridgePort::ProxyARP(false),
                 InfoBridgePort::ProxyARPWifi(false),
-                InfoBridgePort::RootId((
-                    0x0080,
-                    [0x52, 0x54, 0x00, 0xde, 0x0d, 0x2e],
-                )),
-                InfoBridgePort::BridgeId((
-                    0x0080,
-                    [0x52, 0x54, 0x00, 0xde, 0x0d, 0x2e],
-                )),
+                InfoBridgePort::RootId(BridgeId {
+                    priority: 0x8000,
+                    address: [0x52, 0x54, 0x00, 0xde, 0x0d, 0x2e],
+                }),
+                InfoBridgePort::BridgeId(BridgeId {
+                    priority: 0x8000,
+                    address: [0x52, 0x54, 0x00, 0xde, 0x0d, 0x2e],
+                }),
                 InfoBridgePort::DesignatedPort(32769),
                 InfoBridgePort::DesignatedCost(0),
                 InfoBridgePort::PortId(32769),