fix per code review

wakey-agent/src/config.rs

@@ -4,7 +4,10 @@ use std::fmt;
 use std::path::{Path, PathBuf};
 use std::sync::LazyLock;
 
-use crate::protocol::{DEFAULT_TERMINAL_MAX_SESSIONS, DEFAULT_TERMINAL_SESSION_TTL_SECONDS};
+use crate::protocol::{
+    DEFAULT_TERMINAL_MAX_SESSIONS, DEFAULT_TERMINAL_SESSION_TTL_SECONDS,
+    checked_terminal_session_ttl,
+};
 
 pub const DEFAULT_CONFIG_PATH: &str = "/etc/wakey-agent/config.toml";
 pub const DEFAULT_PID_FILE: &str = "/var/run/wakey-agent.pid";
@@ -158,14 +161,7 @@ const fn default_terminal_session_ttl_seconds() -> u64 {
 
 impl TerminalConfig {
     pub(crate) fn session_ttl(&self) -> Result<Option<std::time::Duration>> {
-        if self.session_ttl_seconds == 0 {
-            return Ok(None);
-        }
-        let ttl = std::time::Duration::from_secs(self.session_ttl_seconds);
-        std::time::Instant::now()
-            .checked_add(ttl)
-            .context("terminal.session_ttl_seconds is too large for the platform timer")?;
-        Ok(Some(ttl))
+        checked_terminal_session_ttl(self.session_ttl_seconds).map_err(anyhow::Error::msg)
     }
 }
 

wakey-agent/src/protocol.rs

@@ -2,6 +2,7 @@ use macaddr::MacAddr;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::net::IpAddr;
+use std::time::{Duration, Instant};
 use wakey_core::parse::mac;
 use wakey_core::{
     Device, DeviceInventory, DhcpLeaseWithState, InterfaceSummary, InventoryQuery,
@@ -68,6 +69,21 @@ pub enum AgentCapability {
 pub const DEFAULT_TERMINAL_MAX_SESSIONS: usize = 2;
 pub const DEFAULT_TERMINAL_SESSION_TTL_SECONDS: u64 = 12 * 60 * 60;
 
+/// Validates a terminal TTL against the platform's monotonic timer range.
+/// Zero is the explicit unlimited policy.
+pub fn checked_terminal_session_ttl(
+    session_ttl_seconds: u64,
+) -> Result<Option<Duration>, &'static str> {
+    if session_ttl_seconds == 0 {
+        return Ok(None);
+    }
+    let ttl = Duration::from_secs(session_ttl_seconds);
+    Instant::now()
+        .checked_add(ttl)
+        .ok_or("terminal session TTL is too large for the platform timer")?;
+    Ok(Some(ttl))
+}
+
 const fn default_terminal_session_ttl_seconds() -> u64 {
     DEFAULT_TERMINAL_SESSION_TTL_SECONDS
 }