ts_control 0.4.0

use alloc::collections::BTreeMap;
use core::{
    fmt,
    net::{IpAddr, SocketAddr},
};

use chrono::{DateTime, Utc};
use ts_capabilityversion::CapabilityVersion;
use ts_keys::{DiscoPublicKey, MachinePublicKey, NodePublicKey};

const LAST_SEEN_FORMAT: &str = "%F %T %Z";

/// The unique id of a node.
pub type Id = i64;

/// The stable ID of a node.
#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct StableId(pub String);

/// Timestamps indicating when an offline node was last connected to the control plane. Only applies
/// to nodes that are offline (disconnected from the control plane).
///
/// If populated, most `control` timestamp values are only accurate to a resolution of ~10 minutes
/// for privacy reasons. See each variant for important information on comparison of timestamp
/// values and which clock is used to generate a timestamp.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub struct NodeLastSeen {
    /// The last time the node was connected to the control plane, as reported by the control plane
    /// itself. In some cases, the control plane does not report a "last seen" timestamp, just that
    /// a node is offline; in those cases, this field will be `None`.
    ///
    /// The timestamp may be rounded to the nearest 10-minute boundary before being reported to this
    /// device by the control plane; in other words, many `control` timestamps will be aligned to
    /// 10-minute boundaries. This is a privacy-preserving measure implemented by the control plane.
    /// Note that we have seen some non-rounded timestamps being reported from the control plane,
    /// although it's unclear if this is a bug or by design.
    ///
    /// Note that the timestamp value was generated by the control plane. The control plane's
    /// "clock" isn't synchronized with the local device's clock, so the timestamp value may be
    /// much more than 5 minutes in the past/future when compared to the `estimated` timestamp/local
    /// device clock. Do not directly compare `NodeLastSeen::control` timestamps with
    /// `NodeLastSeen::estimated` timestamps.
    pub control: Option<DateTime<Utc>>,
    /// The last time the node was connected to the control plane, as estimated by this device. The
    /// timestamp is roughly the time this device was notified the node was offline by the control
    /// plane, using the local device clock.
    ///
    /// Note that the timestamp value was generated by the local device clock. The control plane's
    /// "clock" isn't synchronized with the local device's clock, so the timestamp value may differ
    /// greatly from the `control` timestamp/control plane clock. Do not directly compare
    /// `NodeLastSeen::control` timestamps with `NodeLastSeen::estimated` timestamps.
    pub estimated: DateTime<Utc>,
}

impl Default for NodeLastSeen {
    fn default() -> Self {
        Self {
            control: None,
            // We intentionally don't fuzz the estimated timestamp value because the Go client code
            // doesn't either.
            // See: https://github.com/tailscale/tailscale/blob/ee0a03b140021541495b25bdb6642b589431758b/control/controlclient/map.go#L753-L764
            estimated: Utc::now(),
        }
    }
}

impl fmt::Display for NodeLastSeen {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "last seen: {} (by control: ",
            self.estimated.format(LAST_SEEN_FORMAT)
        )?;
        match self.control {
            None => write!(f, "unknown)"),
            Some(dt) => write!(f, "{})", dt.format(LAST_SEEN_FORMAT)),
        }
    }
}

impl NodeLastSeen {
    /// Construct a new `NodeLastSeen` with an optional "last seen by control" timestamp. The
    /// `estimated` timestamp is always set to the current UTC date/time.
    pub fn new(control: Option<DateTime<Utc>>) -> Self {
        Self {
            control,
            ..Default::default()
        }
    }
}

/// Whether a node is online (connected to the control plane) or offline (disconnected from the
/// control plane).
#[derive(Debug, Default, Copy, Clone, PartialEq, Eq, Hash)]
pub enum NodeStatus {
    /// The node may be online or offline; the control plane hasn't informed us yet.
    #[default]
    Unknown,
    /// The node is online (connected to the control plane).
    Online,
    /// The node is offline (disconnected from the control plane).
    Offline(NodeLastSeen),
}

impl fmt::Display for NodeStatus {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            NodeStatus::Unknown => write!(f, "unknown"),
            NodeStatus::Online => write!(f, "online"),
            NodeStatus::Offline(nls) => write!(f, "offline, {nls}"),
        }
    }
}

impl NodeStatus {
    /// Construct a new `NodeStatus` from a combination of online and last-seen timestamp.
    ///
    /// The netmap messages we get from the control plane have multiple ways to indicate a peer is
    /// online and/or the timestamp the peer was last connected to the control plane. This method
    /// wraps the sometimes-painful logic of creating a `NodeStatus` from the various combinations
    /// of netmap field values.
    pub fn new(online: Option<bool>, last_seen: Option<DateTime<Utc>>) -> Self {
        match (online, last_seen) {
            (Some(true), None) => Self::Online,
            (Some(false), None) => Self::Offline(NodeLastSeen::new(None)),
            (Some(false), Some(dt)) | (None, Some(dt)) => {
                Self::Offline(NodeLastSeen::new(Some(dt)))
            }
            (None, None) => Self::Unknown,
            (online, last_seen) => {
                tracing::warn!(
                    ?online,
                    ?last_seen,
                    "unexpected combination of online/last_seen states"
                );
                Self::Unknown
            }
        }
    }
}

/// A node in a tailnet.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Node {
    /// The node's id.
    pub id: Id,
    /// The node's stable id.
    pub stable_id: StableId,
    /// The node's hostname.
    pub hostname: String,

    /// The node's capability version.
    pub capability_version: CapabilityVersion,

    /// Whether the node is connected to the control plane or not. If [`NodeStatus::Unknown`], the
    /// control plane hasn't told us yet.
    ///
    /// This field does _not_ indicate whether the node is reachable or visible from this device.
    pub status: NodeStatus,

    /// The tailnet this node belongs to.
    pub tailnet: Option<String>,

    /// The node capabilities assigned to this node.
    pub node_capabilities: BTreeMap<String, Vec<String>>,

    /// The tags assigned to this node.
    pub tags: Vec<String>,

    /// The address of the node in the tailnet.
    pub tailnet_address: TailnetAddress,

    /// The node's [`NodePublicKey`].
    pub node_key: NodePublicKey,
    /// The node key's expiration.
    pub node_key_expiry: Option<DateTime<Utc>>,

    /// The node's [`MachinePublicKey`], if known.
    pub machine_key: Option<MachinePublicKey>,
    /// The node's [`DiscoPublicKey`], if known.
    pub disco_key: Option<DiscoPublicKey>,
    /// The signature of the node's public key with the Tailnet Lock signing key, if Tailnet Lock
    /// is enabled and the signature is known.
    pub tailnet_lock_key_signature: Option<Vec<u8>>,

    /// The routes this node accepts traffic for.
    pub accepted_routes: Vec<ipnet::IpNet>,
    /// The underlay addresses this node is reachable on (`Endpoints` in Go).
    pub underlay_addresses: Vec<SocketAddr>,

    /// The DERP region for this node, if known.
    pub derp_region: Option<ts_derp::RegionId>,
}

impl Node {
    /// Apply the given partial update to this `Node`.
    ///
    /// # Panics
    /// If `update.id` does not match `self.id`. The caller must guarantee this method is only
    /// called with [`NodeUpdate`]s for this `Node`.
    #[tracing::instrument(skip_all, fields(id = self.stable_id.0, hostname = self.hostname))]
    pub fn apply_update(&mut self, update: &NodeUpdate) {
        assert_eq!(self.id, update.id, "node update ID != node ID");

        if update.status != NodeStatus::Unknown {
            tracing::debug!(old_status = %self.status, "peer {}", update.status);
            self.status = update.status;
        }

        if let Some(cap) = update.cap {
            tracing::debug!(old=?self.capability_version, new=?cap, "updating capability version");
            self.capability_version = cap;
        }

        if let Some(cap_map) = update.cap_map.as_ref() {
            tracing::debug!(old=?self.node_capabilities, new=?cap_map, "updating node capabilities");
            self.node_capabilities = cap_map.clone();
        }

        if let Some(derp_region) = update.derp_region {
            tracing::debug!(old=?self.derp_region, new=?derp_region, "updating derp home region");
            self.derp_region = Some(derp_region);
        }

        if let Some(disco_key) = update.disco_key {
            tracing::debug!(old=?self.disco_key, new=?disco_key, "updating disco key");
            self.disco_key = Some(disco_key);
        }

        if let Some(node_key) = update.node_key {
            tracing::debug!(old=?self.node_key, new=?node_key, "updating node key");
            self.node_key = node_key;
        }

        if let Some(node_key_expiry) = update.node_key_expiry {
            tracing::debug!(old=?self.node_key_expiry, new=?node_key_expiry, "updating node key expiry");
            self.node_key_expiry = Some(node_key_expiry);
        }

        if let Some(tl_sig) = &update.tailnet_lock_key_signature {
            tracing::debug!(old=?self.tailnet_lock_key_signature, new=?tl_sig, "updating tailnet lock key signature");
            self.tailnet_lock_key_signature = Some(tl_sig.clone());
        }

        if let Some(underlay_addresses) = &update.underlay_addresses {
            tracing::debug!(old=?self.underlay_addresses, new=?underlay_addresses, "updating underlay addresses");
            self.underlay_addresses = underlay_addresses.clone();
        }
    }

    /// The fully-qualified domain name of the node.
    ///
    /// This is a string of the form `$HOST.$TAILNET_DOMAIN.`. For tailnets controlled by
    /// Tailscale's control plane, this usually means `$HOST.tail1234.ts.net.`
    ///
    /// The `trailing_dot` parameter specifies whether to include the trailing dot in the
    /// fqdn. This is included by the definition of FQDN, and is the way the Go codebase
    /// formats this field, but the parameter is included to allow turning it off for use
    /// in contexts that expect it to be absent.
    pub fn fqdn(&self, trailing_dot: bool) -> String {
        let dot = if trailing_dot { "." } else { "" };
        match &self.tailnet {
            Some(tailnet) => format!("{}.{tailnet}{dot}", self.hostname),
            None => format!("{}{dot}", self.hostname),
        }
    }

    /// The fully-qualified domain name of the node, only returning `Some` if the tailnet
    /// component is present.
    ///
    /// See [`Node::fqdn`].
    pub fn fqdn_opt(&self, trailing_dot: bool) -> Option<String> {
        let dot = if trailing_dot { "." } else { "" };
        let tailnet = self.tailnet.as_deref()?;

        Some(format!("{}.{tailnet}{dot}", self.hostname))
    }

    /// Report whether this node matches the given `name`.
    ///
    /// `name` is checked for equality with both this node's bare hostname and its fqdn. A
    /// trailing `.` may be present.
    pub fn matches_name(&self, name: &str) -> bool {
        // This approach is taken to avoid allocating a buffer just for the sake of making this
        // comparison: try to chop `.tailnet.` off of the end of `name` and compare the
        // remainder to our hostname. If `.tailnet.` doesn't match `name`, we'll end up comparing
        // our hostname to `hostname.other_tailnet.`, which won't succeed. If `name` was just the
        // hostname, nothing will have been chopped, so the comparison will still be hostname-to-
        // hostname.

        let name = name.strip_suffix('.').unwrap_or(name);

        let name = if let Some(tailnet) = &self.tailnet {
            name.strip_suffix(tailnet.as_str())
                .and_then(|name| name.strip_suffix('.'))
                .unwrap_or(name)
        } else {
            name
        };

        name == self.hostname
    }
}

/// Addresses for a node within a tailnet.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct TailnetAddress {
    /// The IPv4 address of the node in the tailnet.
    pub ipv4: ipnet::Ipv4Net,
    /// The IPv6 address of the node in the tailnet.
    pub ipv6: ipnet::Ipv6Net,
}

impl TailnetAddress {
    /// Report whether `addr` matches either address in this [`TailnetAddress`].
    pub fn contains(&self, addr: IpAddr) -> bool {
        match addr {
            IpAddr::V4(a) => self.ipv4.addr() == a,
            IpAddr::V6(a) => self.ipv6.addr() == a,
        }
    }
}

impl From<&ts_control_serde::Node<'_>> for Node {
    fn from(value: &ts_control_serde::Node) -> Self {
        let fqdn_without_trailing_dot = value.name.strip_suffix('.').unwrap_or(value.name);

        let (hostname, tailnet) = match fqdn_without_trailing_dot.split_once('.') {
            Some((hostname, tailnet)) => (hostname, Some(tailnet.to_owned())),
            None => (fqdn_without_trailing_dot, None),
        };

        Self {
            id: value.id,
            stable_id: StableId(value.stable_id.0.to_string()),
            hostname: hostname.to_owned(),

            capability_version: value.cap,

            status: NodeStatus::new(value.online, value.last_seen),
            tailnet,

            node_capabilities: value
                .cap_map
                .iter()
                .map(|(k, v)| (k.to_string(), v.into()))
                .collect(),
            tags: value
                .tags
                .as_ref()
                .map(|x| x.iter().map(|x| x.to_string()).collect())
                .unwrap_or_default(),

            tailnet_address: TailnetAddress {
                ipv4: value.addresses.0,
                ipv6: value.addresses.1,
            },
            node_key: value.key,
            node_key_expiry: value.key_expiry,
            machine_key: value.machine,
            disco_key: value.disco_key,
            tailnet_lock_key_signature: value.key_signature.as_ref().map(|s| Vec::<u8>::from(*s)),

            accepted_routes: value
                .allowed_ips
                .clone()
                .unwrap_or_else(|| vec![value.addresses.0.into(), value.addresses.1.into()]),
            underlay_addresses: value.endpoints.clone(),

            // legacy_derp_string is still in practical use as of 3/2026
            #[allow(deprecated)]
            derp_region: value
                .home_derp
                .or(value.legacy_derp_string)
                .or_else(|| value.host_info.net_info.as_ref()?.preferred_derp)
                .map(|x| ts_derp::RegionId(x.into())),
        }
    }
}

/// A partial update to a [`Node`] in a tailnet.
///
/// Devices should reject any `NodeUpdate` that it doesn't have a corresponding [`Node`] for. This
/// type combines multiple different update/patch-style fields from netmap messages into a single
/// type to simplify update handling for interested components, such as the peer tracker.
#[derive(Debug, Default, Clone, PartialEq, Eq, Hash)]
pub struct NodeUpdate {
    /// The node's id.
    pub id: Id,

    /// Whether this node is online or offline (with last-seen timestamp), according to the control
    /// plane. If [`NodeStatus::Unknown`], has not changed.
    pub status: NodeStatus,

    /// The DERP region for this node. If `None`, has not changed.
    pub derp_region: Option<ts_derp::RegionId>,

    /// The node's capability version. If `None`, has not changed.
    pub cap: Option<CapabilityVersion>,
    /// The node's capabilities (node caps, not peer caps). If `None`, has not changed.
    pub cap_map: Option<BTreeMap<String, Vec<String>>>,

    /// The node's [`NodePublicKey`]. If `None`, has not changed.
    pub node_key: Option<NodePublicKey>,
    /// The node key's expiration. If `None`, has not changed.
    pub node_key_expiry: Option<DateTime<Utc>>,

    /// The node's [`DiscoPublicKey`]. If `None`, has not changed.
    pub disco_key: Option<DiscoPublicKey>,

    /// The node's key signature for Tailnet Lock. If `None`, has not changed.
    pub tailnet_lock_key_signature: Option<Vec<u8>>,

    /// The underlay addresses this node is reachable on (`Endpoints` in Go). If `None`, has not
    /// changed.
    pub underlay_addresses: Option<Vec<SocketAddr>>,
}

impl From<&ts_control_serde::PeerChange<'_>> for NodeUpdate {
    fn from(value: &ts_control_serde::PeerChange<'_>) -> Self {
        let cap_map = value.cap_map.as_ref().map(|m| {
            m.iter()
                .map(|(name, values)| {
                    (
                        String::from(*name),
                        values
                            .0
                            .iter()
                            .map(|v| v.to_string())
                            .collect::<Vec<String>>(),
                    )
                })
                .collect()
        });

        Self {
            id: value.node_id,
            status: NodeStatus::new(value.online, value.last_seen),
            derp_region: value.derp_region.map(|x| ts_derp::RegionId(x.into())),
            cap: value.cap,
            cap_map,
            node_key: value.key,
            node_key_expiry: value.key_expiry,
            disco_key: value.disco_key,
            tailnet_lock_key_signature: value.key_signature.map(|x| x.into()),
            underlay_addresses: value.endpoints.clone(),
        }
    }
}