Updating control logic

src/dhcp/clientv4.rs

@@ -58,7 +58,7 @@ pub struct Client {
     /// When to send next request
     next_egress: Instant,
     /// When any existing DHCP address will expire.
-    lease_expiration: Instant,
+    lease_expiration: Option<Instant>,
     transaction_id: u32,
 }
 
@@ -104,7 +104,7 @@ impl Client {
             raw_handle,
             next_egress: now,
             transaction_id: 1,
-            lease_expiration: now,
+            lease_expiration: None,
         }
     }
 
@@ -201,7 +201,7 @@ impl Client {
         // once we receive the ack, we can pass the config to the user
         let config = if dhcp_repr.message_type == DhcpMessageType::Ack {
             let lease_duration = dhcp_repr.lease_duration.unwrap_or(DEFAULT_RENEW_INTERVAL * 2);
-            self.lease_expiration = now + Duration::from_secs(lease_duration.into());
+            self.lease_expiration = Some(now + Duration::from_secs(lease_duration.into()));
 
             // RFC 2131 indicates clients should renew a lease halfway through its expiration.
             self.next_egress = now + Duration::from_secs((lease_duration / 2).into());
@@ -256,8 +256,9 @@ impl Client {
             _ => false
         };
 
-        if now >= self.lease_expiration || retries_exceeded {
-            net_debug!("DHCP lease expiration / retries exceeded");
+        let lease_expired = self.lease_expiration.map_or(false, |expiration| now >= expiration);
+
+        if lease_expired || retries_exceeded {
             self.reset(now);
             // Return a config now so that user code assigns the
             // 0.0.0.0/0 address, which will be used sending a DHCP
@@ -292,12 +293,12 @@ impl Client {
             lease_duration: None,
             dns_servers: None,
         };
-
         let mut send_packet = |iface, endpoint, dhcp_repr| {
             send_packet(iface, raw_socket, &endpoint, &dhcp_repr, checksum_caps)
                 .map(|()| None)
         };
 
+
         match self.state {
             ClientState::Discovering => {
                 self.next_egress = now + Duration::from_secs(DISCOVER_TIMEOUT);
@@ -352,6 +353,7 @@ impl Client {
         net_trace!("DHCP reset");
         self.state = ClientState::Discovering;
         self.next_egress = now;
+        self.lease_expiration = None;
     }
 }
 

src/wire/dhcpv4.rs

@@ -877,7 +877,7 @@ mod test {
         0x00, 0x00, 0x39, 0x2, 0x5, 0xdc, 0x37, 0x04, 0x01, 0x03, 0x06, 0x2a, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     ];
 
-    static ACK_BYTES: &[u8] = &[
+    static ACK_DNS_SERVER_BYTES: &[u8] = &[
         0x02, 0x01, 0x06, 0x00, 0xcc, 0x34, 0x75, 0xab, 0x00, 0x00, 0x80, 0x00, 0x0a, 0xff, 0x06, 0x91,
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0xff, 0x06, 0xfe, 0x34, 0x17, 0xeb, 0xc9,
         0xaa, 0x2f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -901,6 +901,11 @@ mod test {
         0x01, 0x4a, 0x06, 0xa3, 0x01, 0x4a, 0x07, 0x2e, 0x01, 0x08, 0xff
     ];
 
+    static ACK_LEASE_TIME_BYTES: &[u8] = &[
+        // TODO: Fill out.
+        0x00,
+    ];
+
     const IP_NULL: Ipv4Address = Ipv4Address([0, 0, 0, 0]);
     const CLIENT_MAC: EthernetAddress = EthernetAddress([0x0, 0x0b, 0x82, 0x01, 0xfc, 0x42]);
     const DHCP_SIZE: u16 = 1500;
@@ -1051,8 +1056,9 @@ mod test {
 
     #[test]
     fn test_parse_ack_dns_servers() {
-        let packet = Packet::new_unchecked(ACK_BYTES);
+        let packet = Packet::new_unchecked(ACK_DNS_SERVER_BYTES);
         let repr = Repr::parse(&packet).unwrap();
+
         // The packet described by ACK_BYTES advertises 4 DNS servers
         // Here we ensure that we correctly parse the first 3 into our fixed
         // length-3 array (see issue #305)
@@ -1061,4 +1067,14 @@ mod test {
             Some(Ipv4Address([163, 1, 74, 7])),
             Some(Ipv4Address([163, 1, 74, 3]))]));
     }
+
+    #[test]
+    fn test_parse_ack_lease_duration() {
+        let packet = Packet::new_unchecked(ACK_LEASE_TIME_BYTES);
+        let repr = Repr::parse(&packet).unwrap();
+
+        // Verify that the lease time in the ACK is properly parsed. The packet contains a lease
+        // duration of 600s.
+        assert_eq!(repr.lease_duration, Some(600));
+    }
 }