rustango 0.27.2

Django-shaped batteries-included web framework for Rust: ORM + migrations + auto-admin + multi-tenancy + audit log + auth (sessions, JWT, OAuth2/OIDC, HMAC) + APIs (ViewSet, OpenAPI auto-derive, JSON:API) + jobs (in-mem + Postgres) + email + media (S3 / R2 / B2 / MinIO + presigned uploads + collections + tags) + production middleware (CSRF, CSP, rate-limiting, compression, idempotency, etc.).
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
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

//! IP allowlist / blocklist middleware — gate routes by client IP.
//!
//! ## Quick start
//!
//! ```ignore
//! use rustango::ip_filter::{IpFilterLayer, IpFilterRouterExt};
//!
//! // Allow only internal admin network
//! let admin_router = Router::new()
//!     .route("/__admin", get(admin_index))
//!     .ip_filter(IpFilterLayer::allow_only(vec!["10.0.0.0/8", "192.168.0.0/16"])?);
//!
//! // Block known abusers
//! let public_router = Router::new()
//!     .route("/api/posts", get(list_posts))
//!     .ip_filter(IpFilterLayer::block(vec!["203.0.113.42"])?);
//! ```
//!
//! Requires `axum::serve(listener, app.into_make_service_with_connect_info::<SocketAddr>())`
//! to populate `ConnectInfo` — without that, every request matches the
//! `<no-ip>` fallback (see `default_decision`).

use std::net::{IpAddr, SocketAddr};
use std::sync::Arc;

use axum::body::Body;
use axum::extract::{ConnectInfo, Request};
use axum::http::{Response, StatusCode};
use axum::middleware::Next;
use axum::Router;

#[derive(Debug, thiserror::Error)]
pub enum IpFilterError {
    #[error("invalid CIDR or IP: {0}")]
    InvalidCidr(String),
}

/// Filter mode.
#[derive(Clone, Debug)]
enum Mode {
    /// Allow only IPs in `nets`. Reject everything else.
    AllowOnly(Vec<CidrRange>),
    /// Block IPs in `nets`. Allow everything else.
    Block(Vec<CidrRange>),
}

/// Configuration for the IP filter.
#[derive(Clone)]
pub struct IpFilterLayer {
    mode: Mode,
    /// What to do when the request has no `ConnectInfo`. Default `false`
    /// (deny — fail closed for AllowOnly, allow for Block).
    pub allow_no_ip: bool,
}

impl IpFilterLayer {
    /// Allow ONLY these CIDR ranges or single IPs. All others get 403.
    ///
    /// # Errors
    /// [`IpFilterError::InvalidCidr`] if any entry doesn't parse.
    pub fn allow_only<I, S>(nets: I) -> Result<Self, IpFilterError>
    where
        I: IntoIterator<Item = S>,
        S: AsRef<str>,
    {
        let nets = parse_all(nets)?;
        Ok(Self {
            mode: Mode::AllowOnly(nets),
            allow_no_ip: false,
        })
    }

    /// BLOCK these CIDR ranges or single IPs. All others pass.
    ///
    /// # Errors
    /// [`IpFilterError::InvalidCidr`] if any entry doesn't parse.
    pub fn block<I, S>(nets: I) -> Result<Self, IpFilterError>
    where
        I: IntoIterator<Item = S>,
        S: AsRef<str>,
    {
        let nets = parse_all(nets)?;
        Ok(Self {
            mode: Mode::Block(nets),
            allow_no_ip: true,
        })
    }

    /// When `true`, requests without `ConnectInfo` are allowed through.
    /// When `false`, they're rejected for AllowOnly and allowed for Block.
    /// Default `false` (fail-closed).
    #[must_use]
    pub fn allow_no_ip(mut self, yes: bool) -> Self {
        self.allow_no_ip = yes;
        self
    }

    /// Decide whether to allow a request from `ip`.
    fn allow(&self, ip: Option<IpAddr>) -> bool {
        let Some(ip) = ip else {
            return self.allow_no_ip;
        };
        match &self.mode {
            Mode::AllowOnly(nets) => nets.iter().any(|n| n.contains(ip)),
            Mode::Block(nets) => !nets.iter().any(|n| n.contains(ip)),
        }
    }
}

/// Extension trait — `.ip_filter(layer)` on Router.
pub trait IpFilterRouterExt {
    #[must_use]
    fn ip_filter(self, layer: IpFilterLayer) -> Self;
}

impl<S: Clone + Send + Sync + 'static> IpFilterRouterExt for Router<S> {
    fn ip_filter(self, layer: IpFilterLayer) -> Self {
        let cfg = Arc::new(layer);
        self.layer(axum::middleware::from_fn(
            move |req: Request<Body>, next: Next| {
                let cfg = cfg.clone();
                async move { handle(cfg, req, next).await }
            },
        ))
    }
}

async fn handle(cfg: Arc<IpFilterLayer>, req: Request<Body>, next: Next) -> Response<Body> {
    let ip = req
        .extensions()
        .get::<ConnectInfo<SocketAddr>>()
        .map(|ci| ci.ip());
    if cfg.allow(ip) {
        next.run(req).await
    } else {
        Response::builder()
            .status(StatusCode::FORBIDDEN)
            .body(Body::from("forbidden"))
            .unwrap()
    }
}

// ------------------------------------------------------------------ CIDR parsing

#[derive(Debug, Clone, Copy)]
enum CidrRange {
    V4 { addr: u32, mask: u32 },
    V6 { addr: u128, mask: u128 },
}

impl CidrRange {
    fn contains(&self, ip: IpAddr) -> bool {
        match (self, ip) {
            (Self::V4 { addr, mask }, IpAddr::V4(v4)) => u32::from(v4) & mask == *addr & mask,
            (Self::V6 { addr, mask }, IpAddr::V6(v6)) => u128::from(v6) & mask == *addr & mask,
            _ => false, // address family mismatch
        }
    }
}

fn parse_all<I, S>(nets: I) -> Result<Vec<CidrRange>, IpFilterError>
where
    I: IntoIterator<Item = S>,
    S: AsRef<str>,
{
    nets.into_iter().map(|s| parse_cidr(s.as_ref())).collect()
}

fn parse_cidr(s: &str) -> Result<CidrRange, IpFilterError> {
    let (ip_str, prefix) = match s.split_once('/') {
        Some((ip, p)) => (ip, Some(p)),
        None => (s, None),
    };
    let ip: IpAddr = ip_str
        .parse()
        .map_err(|_| IpFilterError::InvalidCidr(s.to_owned()))?;

    match ip {
        IpAddr::V4(v4) => {
            let bits: u32 = match prefix {
                Some(p) => p
                    .parse()
                    .map_err(|_| IpFilterError::InvalidCidr(s.to_owned()))?,
                None => 32,
            };
            if bits > 32 {
                return Err(IpFilterError::InvalidCidr(s.to_owned()));
            }
            let mask = if bits == 0 {
                0
            } else {
                u32::MAX << (32 - bits)
            };
            Ok(CidrRange::V4 {
                addr: u32::from(v4) & mask,
                mask,
            })
        }
        IpAddr::V6(v6) => {
            let bits: u32 = match prefix {
                Some(p) => p
                    .parse()
                    .map_err(|_| IpFilterError::InvalidCidr(s.to_owned()))?,
                None => 128,
            };
            if bits > 128 {
                return Err(IpFilterError::InvalidCidr(s.to_owned()));
            }
            let mask = if bits == 0 {
                0u128
            } else {
                u128::MAX << (128 - bits)
            };
            Ok(CidrRange::V6 {
                addr: u128::from(v6) & mask,
                mask,
            })
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::net::{Ipv4Addr, Ipv6Addr};

    fn ip4(s: &str) -> IpAddr {
        IpAddr::V4(s.parse::<Ipv4Addr>().unwrap())
    }

    fn ip6(s: &str) -> IpAddr {
        IpAddr::V6(s.parse::<Ipv6Addr>().unwrap())
    }

    #[test]
    fn parse_single_ipv4() {
        let r = parse_cidr("192.168.1.1").unwrap();
        assert!(r.contains(ip4("192.168.1.1")));
        assert!(!r.contains(ip4("192.168.1.2")));
    }

    #[test]
    fn parse_ipv4_cidr() {
        let r = parse_cidr("10.0.0.0/8").unwrap();
        assert!(r.contains(ip4("10.0.0.1")));
        assert!(r.contains(ip4("10.255.255.255")));
        assert!(!r.contains(ip4("11.0.0.0")));
    }

    #[test]
    fn parse_ipv6_cidr() {
        let r = parse_cidr("fe80::/10").unwrap();
        assert!(r.contains(ip6("fe80::1")));
        assert!(!r.contains(ip6("2001::1")));
    }

    #[test]
    fn parse_zero_prefix_matches_all() {
        let r = parse_cidr("0.0.0.0/0").unwrap();
        assert!(r.contains(ip4("1.2.3.4")));
        assert!(r.contains(ip4("255.255.255.255")));
    }

    #[test]
    fn parse_invalid_returns_error() {
        assert!(parse_cidr("not-an-ip").is_err());
        assert!(parse_cidr("192.168.1.1/33").is_err());
        assert!(parse_cidr("::/129").is_err());
    }

    #[test]
    fn allow_only_passes_listed_ips() {
        let l = IpFilterLayer::allow_only(vec!["10.0.0.0/8"]).unwrap();
        assert!(l.allow(Some(ip4("10.1.2.3"))));
        assert!(!l.allow(Some(ip4("11.0.0.1"))));
    }

    #[test]
    fn allow_only_rejects_unlisted_ips() {
        let l = IpFilterLayer::allow_only(vec!["192.168.0.0/16"]).unwrap();
        assert!(!l.allow(Some(ip4("8.8.8.8"))));
    }

    #[test]
    fn block_rejects_listed_ips() {
        let l = IpFilterLayer::block(vec!["203.0.113.42"]).unwrap();
        assert!(!l.allow(Some(ip4("203.0.113.42"))));
        assert!(l.allow(Some(ip4("203.0.113.43"))));
    }

    #[test]
    fn block_passes_unlisted_ips() {
        let l = IpFilterLayer::block(vec!["10.0.0.0/8"]).unwrap();
        assert!(l.allow(Some(ip4("8.8.8.8"))));
    }

    #[test]
    fn allow_only_no_ip_fails_closed_by_default() {
        let l = IpFilterLayer::allow_only(vec!["10.0.0.0/8"]).unwrap();
        assert!(!l.allow(None));
    }

    #[test]
    fn block_no_ip_fails_open_by_default() {
        let l = IpFilterLayer::block(vec!["10.0.0.0/8"]).unwrap();
        assert!(l.allow(None));
    }

    #[test]
    fn allow_no_ip_override() {
        let l = IpFilterLayer::allow_only(vec!["10.0.0.0/8"])
            .unwrap()
            .allow_no_ip(true);
        assert!(l.allow(None));
    }

    #[test]
    fn cross_family_does_not_match() {
        // IPv4 CIDR shouldn't match IPv6 addresses
        let l = IpFilterLayer::allow_only(vec!["10.0.0.0/8"]).unwrap();
        assert!(!l.allow(Some(ip6("::1"))));
    }
}