toe_beans/v4/server/leases/
lease_time.rs

1use crate::v4::error::Result;
2use serde::{Deserialize, Serialize};
3
4/// The lowest valid value for lease_time (in seconds)
5const MIN_LEASE_TIME: u32 = 60;
6/// Used to adjust for clock drift between client and server (in seconds)
7const DRIFT: u32 = 10;
8
9/// The time, in seconds, before a lease expires.
10/// A lower value will increase dhcp traffic between client and server.
11/// A higher value will increase the chances that all ip addresses are assigned.
12///
13/// Lease time must be at least a minute because:
14/// 1. The server must subtract some time to account for drift.
15/// 2. The default value for T1 (renewal time) is half of the lease_time.
16#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
17pub struct LeaseTime(u32);
18
19impl LeaseTime {
20    /// DHCP reserves the maximum value of 4,294,967,295 to represent a lease that never expires.
21    ///
22    /// This is more performant than `LeaseTime::new`
23    pub const INFINITY: Self = Self(u32::MAX);
24
25    /// The number of seconds in one day (24 hours).
26    /// This is currently used as the default in `LeaseConfig`.
27    pub const ONE_DAY: Self = Self(86_400);
28
29    /// Construct a valid lease_time field.
30    pub fn new(lease_time: u32) -> Result<Self> {
31        if lease_time < MIN_LEASE_TIME {
32            return Err("Lease time cant be less than the minimum lease time (60 seconds)");
33        }
34
35        Ok(Self(lease_time))
36    }
37
38    /// The actual lease_time, not adjusted for drift.
39    pub fn as_server(&self) -> u32 {
40        self.0
41    }
42
43    /// The lease_time, with a small amount subtracted to adjust for drift
44    pub fn as_client(&self) -> u32 {
45        self.0 - DRIFT
46    }
47}
48
49#[cfg(test)]
50mod tests {
51    use super::*;
52
53    #[test]
54    fn test_min_lease_time_greater_than_drift() {
55        assert!(MIN_LEASE_TIME > DRIFT);
56    }
57}
toe_beans/v4/server/leases/lease_time.rs

toe_beans/v4/server/leases/
lease_time.rs
