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feat(transport): Add GlobalOnly Transport implementation
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Upstreams the `GlobalOnly` transport from @mxinden's kademlia-exporter to rust-libp2p.

Source: https://github.com/mxinden/kademlia-exporter/blob/master/src/exporter/client/global_only.rs.

Resolves: #3669.

Pull-Request: #3814.
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@tcoratger
tcoratger authored May 10, 2023
1 parent 541eba3 commit 3fde132
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4 changes: 4 additions & 0 deletions core/CHANGELOG.md
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- Remove `SingletonMuxer`.
See [PR 3883].

- Add `global_only::Transport` that refuses to dial IP addresses from private ranges.
See [PR 3814].

[spec]: https://github.com/libp2p/specs/blob/master/connections/README.md#multistream-select
[PR 3746]: https://github.com/libp2p/rust-libp2p/pull/3746
[PR 3883]: https://github.com/libp2p/rust-libp2p/pull/3883
[PR 3814]: https://github.com/libp2p/rust-libp2p/pull/3814

## 0.39.2

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1 change: 1 addition & 0 deletions core/src/transport.rs
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Expand Up @@ -37,6 +37,7 @@ use std::{
pub mod and_then;
pub mod choice;
pub mod dummy;
pub mod global_only;
pub mod map;
pub mod map_err;
pub mod memory;
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346 changes: 346 additions & 0 deletions core/src/transport/global_only.rs
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// Copyright 2023 Protocol Labs
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use crate::{
multiaddr::{Multiaddr, Protocol},
transport::{ListenerId, TransportError, TransportEvent},
};
use log::debug;
use std::{
pin::Pin,
task::{Context, Poll},
};

/// Dropping all dial requests to non-global IP addresses.
#[derive(Debug, Clone, Default)]
pub struct Transport<T> {
inner: T,
}

/// This module contains an implementation of the `is_global` IPv4 address space.
///
/// Credit for this implementation goes to the Rust standard library team.
///
/// Unstable tracking issue: [#27709](https://github.com/rust-lang/rust/issues/27709)
mod ipv4_global {
use std::net::Ipv4Addr;

/// Returns [`true`] if this address is reserved by IANA for future use. [IETF RFC 1112]
/// defines the block of reserved addresses as `240.0.0.0/4`. This range normally includes the
/// broadcast address `255.255.255.255`, but this implementation explicitly excludes it, since
/// it is obviously not reserved for future use.
///
/// [IETF RFC 1112]: https://tools.ietf.org/html/rfc1112
///
/// # Warning
///
/// As IANA assigns new addresses, this method will be
/// updated. This may result in non-reserved addresses being
/// treated as reserved in code that relies on an outdated version
/// of this method.
#[must_use]
#[inline]
const fn is_reserved(a: Ipv4Addr) -> bool {
a.octets()[0] & 240 == 240 && !a.is_broadcast()
}

/// Returns [`true`] if this address part of the `198.18.0.0/15` range, which is reserved for
/// network devices benchmarking. This range is defined in [IETF RFC 2544] as `192.18.0.0`
/// through `198.19.255.255` but [errata 423] corrects it to `198.18.0.0/15`.
///
/// [IETF RFC 2544]: https://tools.ietf.org/html/rfc2544
/// [errata 423]: https://www.rfc-editor.org/errata/eid423
#[must_use]
#[inline]
const fn is_benchmarking(a: Ipv4Addr) -> bool {
a.octets()[0] == 198 && (a.octets()[1] & 0xfe) == 18
}

/// Returns [`true`] if this address is part of the Shared Address Space defined in
/// [IETF RFC 6598] (`100.64.0.0/10`).
///
/// [IETF RFC 6598]: https://tools.ietf.org/html/rfc6598
#[must_use]
#[inline]
const fn is_shared(a: Ipv4Addr) -> bool {
a.octets()[0] == 100 && (a.octets()[1] & 0b1100_0000 == 0b0100_0000)
}

/// Returns [`true`] if this is a private address.
///
/// The private address ranges are defined in [IETF RFC 1918] and include:
///
/// - `10.0.0.0/8`
/// - `172.16.0.0/12`
/// - `192.168.0.0/16`
///
/// [IETF RFC 1918]: https://tools.ietf.org/html/rfc1918
#[must_use]
#[inline]
const fn is_private(a: Ipv4Addr) -> bool {
match a.octets() {
[10, ..] => true,
[172, b, ..] if b >= 16 && b <= 31 => true,
[192, 168, ..] => true,
_ => false,
}
}

/// Returns [`true`] if the address appears to be globally reachable
/// as specified by the [IANA IPv4 Special-Purpose Address Registry].
/// Whether or not an address is practically reachable will depend on your network configuration.
///
/// Most IPv4 addresses are globally reachable;
/// unless they are specifically defined as *not* globally reachable.
///
/// Non-exhaustive list of notable addresses that are not globally reachable:
///
/// - The [unspecified address] ([`is_unspecified`](Ipv4Addr::is_unspecified))
/// - Addresses reserved for private use ([`is_private`](Ipv4Addr::is_private))
/// - Addresses in the shared address space ([`is_shared`](Ipv4Addr::is_shared))
/// - Loopback addresses ([`is_loopback`](Ipv4Addr::is_loopback))
/// - Link-local addresses ([`is_link_local`](Ipv4Addr::is_link_local))
/// - Addresses reserved for documentation ([`is_documentation`](Ipv4Addr::is_documentation))
/// - Addresses reserved for benchmarking ([`is_benchmarking`](Ipv4Addr::is_benchmarking))
/// - Reserved addresses ([`is_reserved`](Ipv4Addr::is_reserved))
/// - The [broadcast address] ([`is_broadcast`](Ipv4Addr::is_broadcast))
///
/// For the complete overview of which addresses are globally reachable, see the table at the [IANA IPv4 Special-Purpose Address Registry].
///
/// [IANA IPv4 Special-Purpose Address Registry]: https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
/// [unspecified address]: Ipv4Addr::UNSPECIFIED
/// [broadcast address]: Ipv4Addr::BROADCAST
#[must_use]
#[inline]
pub(crate) const fn is_global(a: Ipv4Addr) -> bool {
!(a.octets()[0] == 0 // "This network"
|| is_private(a)
|| is_shared(a)
|| a.is_loopback()
|| a.is_link_local()
// addresses reserved for future protocols (`192.0.0.0/24`)
||(a.octets()[0] == 192 && a.octets()[1] == 0 && a.octets()[2] == 0)
|| a.is_documentation()
|| is_benchmarking(a)
|| is_reserved(a)
|| a.is_broadcast())
}
}

/// This module contains an implementation of the `is_global` IPv6 address space.
///
/// Credit for this implementation goes to the Rust standard library team.
///
/// Unstable tracking issue: [#27709](https://github.com/rust-lang/rust/issues/27709)
mod ipv6_global {
use std::net::Ipv6Addr;

/// Returns `true` if the address is a unicast address with link-local scope,
/// as defined in [RFC 4291].
///
/// A unicast address has link-local scope if it has the prefix `fe80::/10`, as per [RFC 4291 section 2.4].
/// Note that this encompasses more addresses than those defined in [RFC 4291 section 2.5.6],
/// which describes "Link-Local IPv6 Unicast Addresses" as having the following stricter format:
///
/// ```text
/// | 10 bits | 54 bits | 64 bits |
/// +----------+-------------------------+----------------------------+
/// |1111111010| 0 | interface ID |
/// +----------+-------------------------+----------------------------+
/// ```
/// So while currently the only addresses with link-local scope an application will encounter are all in `fe80::/64`,
/// this might change in the future with the publication of new standards. More addresses in `fe80::/10` could be allocated,
/// and those addresses will have link-local scope.
///
/// Also note that while [RFC 4291 section 2.5.3] mentions about the [loopback address] (`::1`) that "it is treated as having Link-Local scope",
/// this does not mean that the loopback address actually has link-local scope and this method will return `false` on it.
///
/// [RFC 4291]: https://tools.ietf.org/html/rfc4291
/// [RFC 4291 section 2.4]: https://tools.ietf.org/html/rfc4291#section-2.4
/// [RFC 4291 section 2.5.3]: https://tools.ietf.org/html/rfc4291#section-2.5.3
/// [RFC 4291 section 2.5.6]: https://tools.ietf.org/html/rfc4291#section-2.5.6
/// [loopback address]: Ipv6Addr::LOCALHOST
#[must_use]
#[inline]
const fn is_unicast_link_local(a: Ipv6Addr) -> bool {
(a.segments()[0] & 0xffc0) == 0xfe80
}

/// Returns [`true`] if this is a unique local address (`fc00::/7`).
///
/// This property is defined in [IETF RFC 4193].
///
/// [IETF RFC 4193]: https://tools.ietf.org/html/rfc4193
#[must_use]
#[inline]
const fn is_unique_local(a: Ipv6Addr) -> bool {
(a.segments()[0] & 0xfe00) == 0xfc00
}

/// Returns [`true`] if this is an address reserved for documentation
/// (`2001:db8::/32`).
///
/// This property is defined in [IETF RFC 3849].
///
/// [IETF RFC 3849]: https://tools.ietf.org/html/rfc3849
#[must_use]
#[inline]
const fn is_documentation(a: Ipv6Addr) -> bool {
(a.segments()[0] == 0x2001) && (a.segments()[1] == 0xdb8)
}

/// Returns [`true`] if the address appears to be globally reachable
/// as specified by the [IANA IPv6 Special-Purpose Address Registry].
/// Whether or not an address is practically reachable will depend on your network configuration.
///
/// Most IPv6 addresses are globally reachable;
/// unless they are specifically defined as *not* globally reachable.
///
/// Non-exhaustive list of notable addresses that are not globally reachable:
/// - The [unspecified address] ([`is_unspecified`](Ipv6Addr::is_unspecified))
/// - The [loopback address] ([`is_loopback`](Ipv6Addr::is_loopback))
/// - IPv4-mapped addresses
/// - Addresses reserved for benchmarking
/// - Addresses reserved for documentation ([`is_documentation`](Ipv6Addr::is_documentation))
/// - Unique local addresses ([`is_unique_local`](Ipv6Addr::is_unique_local))
/// - Unicast addresses with link-local scope ([`is_unicast_link_local`](Ipv6Addr::is_unicast_link_local))
///
/// For the complete overview of which addresses are globally reachable, see the table at the [IANA IPv6 Special-Purpose Address Registry].
///
/// Note that an address having global scope is not the same as being globally reachable,
/// and there is no direct relation between the two concepts: There exist addresses with global scope
/// that are not globally reachable (for example unique local addresses),
/// and addresses that are globally reachable without having global scope
/// (multicast addresses with non-global scope).
///
/// [IANA IPv6 Special-Purpose Address Registry]: https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml
/// [unspecified address]: Ipv6Addr::UNSPECIFIED
/// [loopback address]: Ipv6Addr::LOCALHOST
#[must_use]
#[inline]
pub(crate) const fn is_global(a: Ipv6Addr) -> bool {
!(a.is_unspecified()
|| a.is_loopback()
// IPv4-mapped Address (`::ffff:0:0/96`)
|| matches!(a.segments(), [0, 0, 0, 0, 0, 0xffff, _, _])
// IPv4-IPv6 Translat. (`64:ff9b:1::/48`)
|| matches!(a.segments(), [0x64, 0xff9b, 1, _, _, _, _, _])
// Discard-Only Address Block (`100::/64`)
|| matches!(a.segments(), [0x100, 0, 0, 0, _, _, _, _])
// IETF Protocol Assignments (`2001::/23`)
|| (matches!(a.segments(), [0x2001, b, _, _, _, _, _, _] if b < 0x200)
&& !(
// Port Control Protocol Anycast (`2001:1::1`)
u128::from_be_bytes(a.octets()) == 0x2001_0001_0000_0000_0000_0000_0000_0001
// Traversal Using Relays around NAT Anycast (`2001:1::2`)
|| u128::from_be_bytes(a.octets()) == 0x2001_0001_0000_0000_0000_0000_0000_0002
// AMT (`2001:3::/32`)
|| matches!(a.segments(), [0x2001, 3, _, _, _, _, _, _])
// AS112-v6 (`2001:4:112::/48`)
|| matches!(a.segments(), [0x2001, 4, 0x112, _, _, _, _, _])
// ORCHIDv2 (`2001:20::/28`)
|| matches!(a.segments(), [0x2001, b, _, _, _, _, _, _] if b >= 0x20 && b <= 0x2F)
))
|| is_documentation(a)
|| is_unique_local(a)
|| is_unicast_link_local(a))
}
}

impl<T> Transport<T> {
pub fn new(transport: T) -> Self {
Transport { inner: transport }
}
}

impl<T: crate::Transport + Unpin> crate::Transport for Transport<T> {
type Output = <T as crate::Transport>::Output;
type Error = <T as crate::Transport>::Error;
type ListenerUpgrade = <T as crate::Transport>::ListenerUpgrade;
type Dial = <T as crate::Transport>::Dial;

fn listen_on(&mut self, addr: Multiaddr) -> Result<ListenerId, TransportError<Self::Error>> {
self.inner.listen_on(addr)
}

fn remove_listener(&mut self, id: ListenerId) -> bool {
self.inner.remove_listener(id)
}

fn dial(&mut self, addr: Multiaddr) -> Result<Self::Dial, TransportError<Self::Error>> {
match addr.iter().next() {
Some(Protocol::Ip4(a)) => {
if !ipv4_global::is_global(a) {
debug!("Not dialing non global IP address {:?}.", a);
return Err(TransportError::MultiaddrNotSupported(addr));
}
self.inner.dial(addr)
}
Some(Protocol::Ip6(a)) => {
if !ipv6_global::is_global(a) {
debug!("Not dialing non global IP address {:?}.", a);
return Err(TransportError::MultiaddrNotSupported(addr));
}
self.inner.dial(addr)
}
_ => {
debug!("Not dialing unsupported Multiaddress {:?}.", addr);
Err(TransportError::MultiaddrNotSupported(addr))
}
}
}

fn dial_as_listener(
&mut self,
addr: Multiaddr,
) -> Result<Self::Dial, TransportError<Self::Error>> {
match addr.iter().next() {
Some(Protocol::Ip4(a)) => {
if !ipv4_global::is_global(a) {
debug!("Not dialing non global IP address {:?}.", a);
return Err(TransportError::MultiaddrNotSupported(addr));
}
self.inner.dial_as_listener(addr)
}
Some(Protocol::Ip6(a)) => {
if !ipv6_global::is_global(a) {
debug!("Not dialing non global IP address {:?}.", a);
return Err(TransportError::MultiaddrNotSupported(addr));
}
self.inner.dial_as_listener(addr)
}
_ => {
debug!("Not dialing unsupported Multiaddress {:?}.", addr);
Err(TransportError::MultiaddrNotSupported(addr))
}
}
}

fn address_translation(&self, listen: &Multiaddr, observed: &Multiaddr) -> Option<Multiaddr> {
self.inner.address_translation(listen, observed)
}

fn poll(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<TransportEvent<Self::ListenerUpgrade, Self::Error>> {
Pin::new(&mut self.inner).poll(cx)
}
}

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