[PATCH proxmox v2 3/8] network-types: add ServiceEndpoint type as host/port tuple abstraction

[Christoph Heiss <c.heiss@proxmox.com>]

Basically a composite data type to provide bit of an better abstraction
to a tuple (host, port).

Signed-off-by: Christoph Heiss <c.heiss@proxmox.com>
---
Changes v1 -> v2:
  * forward to `Display` impl directly where possible

 proxmox-network-types/src/endpoint.rs | 154 ++++++++++++++++++++++++++
 proxmox-network-types/src/lib.rs      |   3 +-
 2 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 proxmox-network-types/src/endpoint.rs

diff --git a/proxmox-network-types/src/endpoint.rs b/proxmox-network-types/src/endpoint.rs
new file mode 100644
index 00000000..10f6a813
--- /dev/null
+++ b/proxmox-network-types/src/endpoint.rs
@@ -0,0 +1,154 @@
+//! Implements a wrapper around a (host, port) tuple, where host can either
+//! be a plain IP address or a resolvable hostname.
+
+use std::{
+    fmt::{self, Display},
+    net::IpAddr,
+    str::FromStr,
+};
+
+use serde_with::{DeserializeFromStr, SerializeDisplay};
+
+/// Represents either a resolvable hostname or an IPv4/IPv6 address.
+/// IPv6 address are correctly bracketed on [`Display`], and parsing
+/// automatically tries parsing it as an IP address first, falling back to a
+/// plain hostname in the other case.
+#[derive(Clone, Debug, PartialEq)]
+pub enum HostnameOrIpAddr {
+    Hostname(String),
+    IpAddr(IpAddr),
+}
+
+impl Display for HostnameOrIpAddr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            HostnameOrIpAddr::Hostname(s) => Display::fmt(s, f),
+            HostnameOrIpAddr::IpAddr(addr) => match addr {
+                IpAddr::V4(v4) => Display::fmt(v4, f),
+                IpAddr::V6(v6) => write!(f, "[{v6}]"),
+            },
+        }
+    }
+}
+
+impl<S: Into<String>> From<S> for HostnameOrIpAddr {
+    fn from(value: S) -> Self {
+        let s = value.into();
+        if let Ok(ip_addr) = IpAddr::from_str(&s) {
+            Self::IpAddr(ip_addr)
+        } else {
+            Self::Hostname(s)
+        }
+    }
+}
+
+/// Represents a (host, port) tuple, where the host can either be a resolvable
+/// hostname or an IPv4/IPv6 address.
+#[derive(Clone, Debug, PartialEq, SerializeDisplay, DeserializeFromStr)]
+pub struct ServiceEndpoint {
+    host: HostnameOrIpAddr,
+    port: u16,
+}
+
+impl ServiceEndpoint {
+    pub fn new<S: Into<String>>(host: S, port: u16) -> Self {
+        let s = host.into();
+        Self {
+            host: s.into(),
+            port,
+        }
+    }
+}
+
+impl Display for ServiceEndpoint {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}:{}", self.host, self.port)
+    }
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum ParseError {
+    #[error("host and port must be separated by a colon")]
+    MissingSeparator,
+    #[error("host part missing")]
+    MissingHost,
+    #[error("invalid port: {0}")]
+    InvalidPort(String),
+}
+
+impl FromStr for ServiceEndpoint {
+    type Err = ParseError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let (mut host, port) = s.rsplit_once(':').ok_or(Self::Err::MissingSeparator)?;
+
+        if host.is_empty() {
+            return Err(Self::Err::MissingHost);
+        }
+
+        // [ and ] are not valid characters in a hostname, so strip them in case it
+        // is a IPv6 address.
+        host = host.trim_matches(['[', ']']);
+
+        Ok(ServiceEndpoint {
+            host: host.into(),
+            port: port
+                .parse()
+                .map_err(|err: std::num::ParseIntError| Self::Err::InvalidPort(err.to_string()))?,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::endpoint::HostnameOrIpAddr;
+
+    use super::ServiceEndpoint;
+
+    #[test]
+    fn display_works() {
+        let s = ServiceEndpoint::new("127.0.0.1", 123);
+        assert_eq!(s.to_string(), "127.0.0.1:123");
+
+        let s = ServiceEndpoint::new("fc00:f00d::4321", 123);
+        assert_eq!(s.to_string(), "[fc00:f00d::4321]:123");
+
+        let s = ServiceEndpoint::new("::", 123);
+        assert_eq!(s.to_string(), "[::]:123");
+
+        let s = ServiceEndpoint::new("fc00::", 123);
+        assert_eq!(s.to_string(), "[fc00::]:123");
+
+        let s = ServiceEndpoint::new("example.com", 123);
+        assert_eq!(s.to_string(), "example.com:123");
+    }
+
+    #[test]
+    fn fromstr_works() {
+        assert_eq!(
+            "127.0.0.1:123".parse::<ServiceEndpoint>().unwrap(),
+            ServiceEndpoint {
+                host: HostnameOrIpAddr::IpAddr([127, 0, 0, 1].into()),
+                port: 123
+            }
+        );
+
+        assert_eq!(
+            "[::1]:123".parse::<ServiceEndpoint>().unwrap(),
+            ServiceEndpoint {
+                host: HostnameOrIpAddr::IpAddr(
+                    [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1].into()
+                ),
+                port: 123
+            }
+        );
+
+        assert_eq!(
+            "example.com:123".parse::<ServiceEndpoint>().unwrap(),
+            ServiceEndpoint {
+                host: HostnameOrIpAddr::Hostname("example.com".to_owned()),
+                port: 123
+            }
+        );
+    }
+}
diff --git a/proxmox-network-types/src/lib.rs b/proxmox-network-types/src/lib.rs
index ee26b1c1..1bacbaf3 100644
--- a/proxmox-network-types/src/lib.rs
+++ b/proxmox-network-types/src/lib.rs
@@ -1,5 +1,6 @@
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
-#![deny(unsafe_op_in_unsafe_fn)]
+#![deny(unsafe_code, unsafe_op_in_unsafe_fn)]
 
+pub mod endpoint;
 pub mod ip_address;
 pub mod mac_address;
-- 
2.52.0