netstack3_base/
matchers.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5//! Trait definition for matchers.
6
7use alloc::string::String;
8use core::fmt::Debug;
9
10use net_types::ip::{IpAddress, Subnet};
11
12use crate::DeviceWithName;
13
14/// Common pattern to define a matcher for a metadata input `T`.
15///
16/// Used in matching engines like filtering and routing rules.
17pub trait Matcher<T> {
18    /// Returns whether the provided value matches.
19    fn matches(&self, actual: &T) -> bool;
20
21    /// Returns whether the provided value is set and matches.
22    fn required_matches(&self, actual: Option<&T>) -> bool {
23        actual.map_or(false, |actual| self.matches(actual))
24    }
25}
26
27/// Implement `Matcher` for optional matchers, so that if a matcher is left
28/// unspecified, it matches all inputs by default.
29impl<T, O> Matcher<T> for Option<O>
30where
31    O: Matcher<T>,
32{
33    fn matches(&self, actual: &T) -> bool {
34        self.as_ref().map_or(true, |expected| expected.matches(actual))
35    }
36
37    fn required_matches(&self, actual: Option<&T>) -> bool {
38        self.as_ref().map_or(true, |expected| expected.required_matches(actual))
39    }
40}
41
42/// Matcher that matches IP addresses in a subnet.
43#[derive(Debug, Copy, Clone, PartialEq, Eq)]
44pub struct SubnetMatcher<A: IpAddress>(pub Subnet<A>);
45
46impl<A: IpAddress> Matcher<A> for SubnetMatcher<A> {
47    fn matches(&self, actual: &A) -> bool {
48        let Self(matcher) = self;
49        matcher.contains(actual)
50    }
51}
52
53/// Matcher that matches devices with the name.
54#[derive(Debug, Clone, PartialEq, Eq)]
55pub struct DeviceNameMatcher(pub String);
56
57impl<D: DeviceWithName> Matcher<D> for DeviceNameMatcher {
58    fn matches(&self, actual: &D) -> bool {
59        let Self(name) = self;
60        actual.name_matches(name)
61    }
62}
63
64#[cfg(test)]
65mod tests {
66    use alloc::format;
67
68    use ip_test_macro::ip_test;
69    use net_types::ip::Ip;
70
71    use super::*;
72    use crate::testutil::{FakeDeviceId, TestIpExt};
73    use crate::DeviceNameMatcher;
74
75    /// Only matches `true`.
76    #[derive(Debug)]
77    struct TrueMatcher;
78
79    impl Matcher<bool> for TrueMatcher {
80        fn matches(&self, actual: &bool) -> bool {
81            *actual
82        }
83    }
84
85    #[test]
86    fn test_optional_matcher_optional_value() {
87        assert!(TrueMatcher.matches(&true));
88        assert!(!TrueMatcher.matches(&false));
89
90        assert!(TrueMatcher.required_matches(Some(&true)));
91        assert!(!TrueMatcher.required_matches(Some(&false)));
92        assert!(!TrueMatcher.required_matches(None));
93
94        assert!(Some(TrueMatcher).matches(&true));
95        assert!(!Some(TrueMatcher).matches(&false));
96        assert!(None::<TrueMatcher>.matches(&true));
97        assert!(None::<TrueMatcher>.matches(&false));
98
99        assert!(Some(TrueMatcher).required_matches(Some(&true)));
100        assert!(!Some(TrueMatcher).required_matches(Some(&false)));
101        assert!(!Some(TrueMatcher).required_matches(None));
102        assert!(None::<TrueMatcher>.required_matches(Some(&true)));
103        assert!(None::<TrueMatcher>.required_matches(Some(&false)));
104        assert!(None::<TrueMatcher>.required_matches(None));
105    }
106
107    #[test]
108    fn device_name_matcher() {
109        let device = FakeDeviceId;
110        let positive_matcher = DeviceNameMatcher(FakeDeviceId::FAKE_NAME.into());
111        let negative_matcher = DeviceNameMatcher(format!("DONTMATCH-{}", FakeDeviceId::FAKE_NAME));
112        assert!(positive_matcher.matches(&device));
113        assert!(!negative_matcher.matches(&device));
114    }
115
116    #[ip_test(I)]
117    fn subnet_matcher<I: Ip + TestIpExt>() {
118        let matcher = SubnetMatcher(I::TEST_ADDRS.subnet);
119        assert!(matcher.matches(&I::TEST_ADDRS.local_ip));
120        assert!(!matcher.matches(&I::get_other_remote_ip_address(1)));
121    }
122}
netstack3_base/matchers.rs

netstack3_base/
matchers.rs
