smoltcp/iface/
route.rs

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
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
use heapless::Vec;

use crate::config::IFACE_MAX_ROUTE_COUNT;
use crate::time::Instant;
use crate::wire::{IpAddress, IpCidr};
#[cfg(feature = "proto-ipv4")]
use crate::wire::{Ipv4Address, Ipv4Cidr};
#[cfg(feature = "proto-ipv6")]
use crate::wire::{Ipv6Address, Ipv6Cidr};

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub struct RouteTableFull;

impl core::fmt::Display for RouteTableFull {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(f, "Route table full")
    }
}

#[cfg(feature = "std")]
impl std::error::Error for RouteTableFull {}

/// A prefix of addresses that should be routed via a router
#[derive(Debug, Clone, Copy)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub struct Route {
    pub cidr: IpCidr,
    pub via_router: IpAddress,
    /// `None` means "forever".
    pub preferred_until: Option<Instant>,
    /// `None` means "forever".
    pub expires_at: Option<Instant>,
}

#[cfg(feature = "proto-ipv4")]
const IPV4_DEFAULT: IpCidr = IpCidr::Ipv4(Ipv4Cidr::new(Ipv4Address::new(0, 0, 0, 0), 0));
#[cfg(feature = "proto-ipv6")]
const IPV6_DEFAULT: IpCidr =
    IpCidr::Ipv6(Ipv6Cidr::new(Ipv6Address::new(0, 0, 0, 0, 0, 0, 0, 0), 0));

impl Route {
    /// Returns a route to 0.0.0.0/0 via the `gateway`, with no expiry.
    #[cfg(feature = "proto-ipv4")]
    pub fn new_ipv4_gateway(gateway: Ipv4Address) -> Route {
        Route {
            cidr: IPV4_DEFAULT,
            via_router: gateway.into(),
            preferred_until: None,
            expires_at: None,
        }
    }

    /// Returns a route to ::/0 via the `gateway`, with no expiry.
    #[cfg(feature = "proto-ipv6")]
    pub fn new_ipv6_gateway(gateway: Ipv6Address) -> Route {
        Route {
            cidr: IPV6_DEFAULT,
            via_router: gateway.into(),
            preferred_until: None,
            expires_at: None,
        }
    }
}

/// A routing table.
#[derive(Debug)]
pub struct Routes {
    storage: Vec<Route, IFACE_MAX_ROUTE_COUNT>,
}

impl Routes {
    /// Creates a new empty routing table.
    pub fn new() -> Self {
        Self {
            storage: Vec::new(),
        }
    }

    /// Update the routes of this node.
    pub fn update<F: FnOnce(&mut Vec<Route, IFACE_MAX_ROUTE_COUNT>)>(&mut self, f: F) {
        f(&mut self.storage);
    }

    /// Add a default ipv4 gateway (ie. "ip route add 0.0.0.0/0 via `gateway`").
    ///
    /// On success, returns the previous default route, if any.
    #[cfg(feature = "proto-ipv4")]
    pub fn add_default_ipv4_route(
        &mut self,
        gateway: Ipv4Address,
    ) -> Result<Option<Route>, RouteTableFull> {
        let old = self.remove_default_ipv4_route();
        self.storage
            .push(Route::new_ipv4_gateway(gateway))
            .map_err(|_| RouteTableFull)?;
        Ok(old)
    }

    /// Add a default ipv6 gateway (ie. "ip -6 route add ::/0 via `gateway`").
    ///
    /// On success, returns the previous default route, if any.
    #[cfg(feature = "proto-ipv6")]
    pub fn add_default_ipv6_route(
        &mut self,
        gateway: Ipv6Address,
    ) -> Result<Option<Route>, RouteTableFull> {
        let old = self.remove_default_ipv6_route();
        self.storage
            .push(Route::new_ipv6_gateway(gateway))
            .map_err(|_| RouteTableFull)?;
        Ok(old)
    }

    /// Remove the default ipv4 gateway
    ///
    /// On success, returns the previous default route, if any.
    #[cfg(feature = "proto-ipv4")]
    pub fn remove_default_ipv4_route(&mut self) -> Option<Route> {
        if let Some((i, _)) = self
            .storage
            .iter()
            .enumerate()
            .find(|(_, r)| r.cidr == IPV4_DEFAULT)
        {
            Some(self.storage.remove(i))
        } else {
            None
        }
    }

    /// Remove the default ipv6 gateway
    ///
    /// On success, returns the previous default route, if any.
    #[cfg(feature = "proto-ipv6")]
    pub fn remove_default_ipv6_route(&mut self) -> Option<Route> {
        if let Some((i, _)) = self
            .storage
            .iter()
            .enumerate()
            .find(|(_, r)| r.cidr == IPV6_DEFAULT)
        {
            Some(self.storage.remove(i))
        } else {
            None
        }
    }

    pub(crate) fn lookup(&self, addr: &IpAddress, timestamp: Instant) -> Option<IpAddress> {
        assert!(addr.is_unicast());

        self.storage
            .iter()
            // Keep only matching routes
            .filter(|route| {
                if let Some(expires_at) = route.expires_at {
                    if timestamp > expires_at {
                        return false;
                    }
                }
                route.cidr.contains_addr(addr)
            })
            // pick the most specific one (highest prefix_len)
            .max_by_key(|route| route.cidr.prefix_len())
            .map(|route| route.via_router)
    }
}

#[cfg(test)]
mod test {
    use super::*;
    #[cfg(feature = "proto-ipv6")]
    mod mock {
        use super::super::*;
        pub const ADDR_1A: Ipv6Address =
            Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1]);
        pub const ADDR_1B: Ipv6Address =
            Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 13]);
        pub const ADDR_1C: Ipv6Address =
            Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 42]);
        pub fn cidr_1() -> Ipv6Cidr {
            Ipv6Cidr::new(
                Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0]),
                64,
            )
        }

        pub const ADDR_2A: Ipv6Address =
            Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 51, 100, 0, 0, 0, 0, 0, 0, 0, 1]);
        pub const ADDR_2B: Ipv6Address =
            Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 51, 100, 0, 0, 0, 0, 0, 0, 0, 21]);
        pub fn cidr_2() -> Ipv6Cidr {
            Ipv6Cidr::new(
                Ipv6Address([0xfe, 0x80, 0, 0, 0, 0, 51, 100, 0, 0, 0, 0, 0, 0, 0, 0]),
                64,
            )
        }
    }

    #[cfg(all(feature = "proto-ipv4", not(feature = "proto-ipv6")))]
    mod mock {
        use super::super::*;
        pub const ADDR_1A: Ipv4Address = Ipv4Address([192, 0, 2, 1]);
        pub const ADDR_1B: Ipv4Address = Ipv4Address([192, 0, 2, 13]);
        pub const ADDR_1C: Ipv4Address = Ipv4Address([192, 0, 2, 42]);
        pub fn cidr_1() -> Ipv4Cidr {
            Ipv4Cidr::new(Ipv4Address([192, 0, 2, 0]), 24)
        }

        pub const ADDR_2A: Ipv4Address = Ipv4Address([198, 51, 100, 1]);
        pub const ADDR_2B: Ipv4Address = Ipv4Address([198, 51, 100, 21]);
        pub fn cidr_2() -> Ipv4Cidr {
            Ipv4Cidr::new(Ipv4Address([198, 51, 100, 0]), 24)
        }
    }

    use self::mock::*;

    #[test]
    fn test_fill() {
        let mut routes = Routes::new();

        assert_eq!(
            routes.lookup(&ADDR_1A.into(), Instant::from_millis(0)),
            None
        );
        assert_eq!(
            routes.lookup(&ADDR_1B.into(), Instant::from_millis(0)),
            None
        );
        assert_eq!(
            routes.lookup(&ADDR_1C.into(), Instant::from_millis(0)),
            None
        );
        assert_eq!(
            routes.lookup(&ADDR_2A.into(), Instant::from_millis(0)),
            None
        );
        assert_eq!(
            routes.lookup(&ADDR_2B.into(), Instant::from_millis(0)),
            None
        );

        let route = Route {
            cidr: cidr_1().into(),
            via_router: ADDR_1A.into(),
            preferred_until: None,
            expires_at: None,
        };
        routes.update(|storage| {
            storage.push(route).unwrap();
        });

        assert_eq!(
            routes.lookup(&ADDR_1A.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1B.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1C.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_2A.into(), Instant::from_millis(0)),
            None
        );
        assert_eq!(
            routes.lookup(&ADDR_2B.into(), Instant::from_millis(0)),
            None
        );

        let route2 = Route {
            cidr: cidr_2().into(),
            via_router: ADDR_2A.into(),
            preferred_until: Some(Instant::from_millis(10)),
            expires_at: Some(Instant::from_millis(10)),
        };
        routes.update(|storage| {
            storage.push(route2).unwrap();
        });

        assert_eq!(
            routes.lookup(&ADDR_1A.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1B.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1C.into(), Instant::from_millis(0)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_2A.into(), Instant::from_millis(0)),
            Some(ADDR_2A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_2B.into(), Instant::from_millis(0)),
            Some(ADDR_2A.into())
        );

        assert_eq!(
            routes.lookup(&ADDR_1A.into(), Instant::from_millis(10)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1B.into(), Instant::from_millis(10)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_1C.into(), Instant::from_millis(10)),
            Some(ADDR_1A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_2A.into(), Instant::from_millis(10)),
            Some(ADDR_2A.into())
        );
        assert_eq!(
            routes.lookup(&ADDR_2B.into(), Instant::from_millis(10)),
            Some(ADDR_2A.into())
        );
    }
}