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Introduce private helper method in_network for Ipv{4,6}Addr #86969

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Introduce private helper method in_network for Ipv{4,6}Addr #86969

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70 changes: 47 additions & 23 deletions library/std/src/net/ip.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -444,12 +444,9 @@ impl Ipv4Addr {
#[stable(since = "1.7.0", feature = "ip_17")]
#[inline]
pub const fn is_private(&self) -> bool {
match self.octets() {
[10, ..] => true,
[172, b, ..] if b >= 16 && b <= 31 => true,
[192, 168, ..] => true,
_ => false,
}
self.in_network(&Ipv4Addr::new(10, 0, 0, 0), 8)
|| self.in_network(&Ipv4Addr::new(172, 16, 0, 0), 12)
|| self.in_network(&Ipv4Addr::new(192, 168, 0, 0), 16)
}

/// Returns [`true`] if the address is link-local (`169.254.0.0/16`).
Expand All @@ -471,7 +468,7 @@ impl Ipv4Addr {
#[stable(since = "1.7.0", feature = "ip_17")]
#[inline]
pub const fn is_link_local(&self) -> bool {
matches!(self.octets(), [169, 254, ..])
self.in_network(&Ipv4Addr::new(169, 254, 0, 0), 16)
}

/// Returns [`true`] if the address appears to be globally routable.
Expand Down Expand Up @@ -564,7 +561,7 @@ impl Ipv4Addr {
&& !self.is_reserved()
&& !self.is_benchmarking()
// Make sure the address is not in 0.0.0.0/8
&& self.octets()[0] != 0
&& !self.in_network(&Ipv4Addr::UNSPECIFIED, 8)
}

/// Returns [`true`] if this address is part of the Shared Address Space defined in
Expand All @@ -586,7 +583,7 @@ impl Ipv4Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_shared(&self) -> bool {
self.octets()[0] == 100 && (self.octets()[1] & 0b1100_0000 == 0b0100_0000)
self.in_network(&Ipv4Addr::new(100, 64, 0, 0), 10)
}

/// Returns [`true`] if this address is part of `192.0.0.0/24`, which is reserved to
Expand Down Expand Up @@ -620,7 +617,7 @@ impl Ipv4Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_ietf_protocol_assignment(&self) -> bool {
self.octets()[0] == 192 && self.octets()[1] == 0 && self.octets()[2] == 0
self.in_network(&Ipv4Addr::new(192, 0, 0, 0), 24)
}

/// Returns [`true`] if this address part of the `198.18.0.0/15` range, which is reserved for
Expand All @@ -645,7 +642,7 @@ impl Ipv4Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_benchmarking(&self) -> bool {
self.octets()[0] == 198 && (self.octets()[1] & 0xfe) == 18
self.in_network(&Ipv4Addr::new(198, 18, 0, 0), 15)
}

/// Returns [`true`] if this address is reserved by IANA for future use. [IETF RFC 1112]
Expand Down Expand Up @@ -679,7 +676,7 @@ impl Ipv4Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_reserved(&self) -> bool {
self.octets()[0] & 240 == 240 && !self.is_broadcast()
self.in_network(&Ipv4Addr::new(240, 0, 0, 0), 4) && !self.is_broadcast()
}

/// Returns [`true`] if this is a multicast address (`224.0.0.0/4`).
Expand All @@ -702,7 +699,7 @@ impl Ipv4Addr {
#[stable(since = "1.7.0", feature = "ip_17")]
#[inline]
pub const fn is_multicast(&self) -> bool {
self.octets()[0] >= 224 && self.octets()[0] <= 239
self.in_network(&Ipv4Addr::new(224, 0, 0, 0), 4)
}

/// Returns [`true`] if this is a broadcast address (`255.255.255.255`).
Expand Down Expand Up @@ -750,12 +747,9 @@ impl Ipv4Addr {
#[stable(since = "1.7.0", feature = "ip_17")]
#[inline]
pub const fn is_documentation(&self) -> bool {
match self.octets() {
[192, 0, 2, _] => true,
[198, 51, 100, _] => true,
[203, 0, 113, _] => true,
_ => false,
}
self.in_network(&Ipv4Addr::new(192, 0, 2, 0), 24)
|| self.in_network(&Ipv4Addr::new(198, 51, 100, 0), 24)
|| self.in_network(&Ipv4Addr::new(203, 0, 113, 0), 24)
}

/// Converts this address to an IPv4-compatible [`IPv6` address].
Expand Down Expand Up @@ -810,6 +804,21 @@ impl Ipv4Addr {
inner: c::in6_addr { s6_addr: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, a, b, c, d] },
}
}

// Internal helper method to check if an IPv4 address is in a network.
// Not intended to be made public in it's current form.
//
// `prefix` must be <=32 and `network` must have all bits not in the prefix set to 0.
#[inline]
const fn in_network(&self, network: &Self, prefix: u8) -> bool {
if prefix == 0 {
true
} else {
// shift will not overflow as prefix > 0, so u32::BITS - prefix < 32
let mask: u32 = u32::MAX << (u32::BITS as u8 - prefix);
u32::from_be_bytes(self.octets()) & mask == u32::from_be_bytes(network.octets())
}
}
}

#[stable(feature = "ip_addr", since = "1.7.0")]
Expand Down Expand Up @@ -1264,7 +1273,7 @@ impl Ipv6Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_unique_local(&self) -> bool {
(self.segments()[0] & 0xfe00) == 0xfc00
self.in_network(&Ipv6Addr::new(0xfc00, 0, 0, 0, 0, 0, 0, 0), 7)
}

/// Returns [`true`] if this is a unicast address, as defined by [IETF RFC 4291].
Expand Down Expand Up @@ -1343,7 +1352,7 @@ impl Ipv6Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_unicast_link_local(&self) -> bool {
(self.segments()[0] & 0xffc0) == 0xfe80
self.in_network(&Ipv6Addr::new(0xfe80, 0, 0, 0, 0, 0, 0, 0), 10)
}

/// Returns [`true`] if this is an address reserved for documentation
Expand All @@ -1367,7 +1376,7 @@ impl Ipv6Addr {
#[unstable(feature = "ip", issue = "27709")]
#[inline]
pub const fn is_documentation(&self) -> bool {
(self.segments()[0] == 0x2001) && (self.segments()[1] == 0xdb8)
self.in_network(&Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0), 32)
}

/// Returns [`true`] if the address is a globally routable unicast address.
Expand Down Expand Up @@ -1465,7 +1474,7 @@ impl Ipv6Addr {
#[stable(since = "1.7.0", feature = "ip_17")]
#[inline]
pub const fn is_multicast(&self) -> bool {
(self.segments()[0] & 0xff00) == 0xff00
self.in_network(&Ipv6Addr::new(0xff00, 0, 0, 0, 0, 0, 0, 0), 8)
}

/// Converts this address to an [`IPv4` address] if it's an "IPv4-mapped IPv6 address"
Expand Down Expand Up @@ -1546,6 +1555,21 @@ impl Ipv6Addr {
pub const fn octets(&self) -> [u8; 16] {
self.inner.s6_addr
}

// Internal helper method to check if an IPv6 address is in a network.
// Not intended to be made public in it's current form.
//
// `prefix` must be <=128 and `network` must have all bits not in the prefix set to 0.
#[inline]
const fn in_network(&self, network: &Self, prefix: u8) -> bool {
if prefix == 0 {
true
} else {
// shift will not overflow as prefix > 0, so u128::BITS - prefix < 128
let mask: u128 = u128::MAX << (u128::BITS as u8 - prefix);
u128::from_be_bytes(self.octets()) & mask == u128::from_be_bytes(network.octets())
}
}
}

/// Write an Ipv6Addr, conforming to the canonical style described by
Expand Down
50 changes: 50 additions & 0 deletions library/std/src/net/ip/tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -781,6 +781,56 @@ fn cmp() {
assert!(IpAddr::V4(v41) < v61);
}

#[test]
fn in_network_ipv4() {
let address = Ipv4Addr::new(1, 2, 3, 4);
assert!(address.in_network(&Ipv4Addr::new(0, 0, 0, 0), 0));
assert!(address.in_network(&Ipv4Addr::new(1, 0, 0, 0), 8));
assert!(address.in_network(&Ipv4Addr::new(1, 2, 0, 0), 16));
assert!(address.in_network(&Ipv4Addr::new(1, 2, 3, 0), 24));
assert!(address.in_network(&Ipv4Addr::new(1, 2, 3, 4), 32));

// test a prefix that is not a multiple of 8
let network = Ipv4Addr::new(0, 0b01100100, 0, 0);
assert_eq!(Ipv4Addr::new(0, 0b01100011, 0, 0).in_network(&network, 14), false);
assert_eq!(Ipv4Addr::new(0, 0b01100100, 0, 0).in_network(&network, 14), true);
assert_eq!(Ipv4Addr::new(0, 0b01100111, 0, 0).in_network(&network, 14), true);
assert_eq!(Ipv4Addr::new(0, 0b01101000, 0, 0).in_network(&network, 14), false);
}

#[test]
fn in_network_ipv6() {
let address = Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8);
assert!(address.in_network(&Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0), 0));
assert!(address.in_network(&Ipv6Addr::new(1, 0, 0, 0, 0, 0, 0, 0), 16));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 0, 0, 0, 0, 0, 0), 32));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 0, 0, 0, 0, 0), 48));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 4, 0, 0, 0, 0), 64));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 4, 5, 0, 0, 0), 80));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 4, 5, 6, 0, 0), 96));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 0), 112));
assert!(address.in_network(&Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 128));

// test a prefix that is not a multiple of 16
let network = Ipv6Addr::new(0, 0b01100100_00000000, 0, 0, 0, 0, 0, 0);
assert_eq!(
Ipv6Addr::new(0, 0b01100011_11111111, 0, 0, 0, 0, 0, 0).in_network(&network, 22),
false
);
assert_eq!(
Ipv6Addr::new(0, 0b01100100_00000000, 0, 0, 0, 0, 0, 0).in_network(&network, 22),
true
);
assert_eq!(
Ipv6Addr::new(0, 0b01100111_11111111, 0, 0, 0, 0, 0, 0).in_network(&network, 22),
true
);
assert_eq!(
Ipv6Addr::new(0, 0b01101000_00000000, 0, 0, 0, 0, 0, 0).in_network(&network, 22),
false
);
}

#[test]
fn is_v4() {
let ip = IpAddr::V4(Ipv4Addr::new(100, 64, 3, 3));
Expand Down