RFC2131 Section 3.1 mentions a scenario where the client is supposed to
drop its lease using DHCPDECLINE after sending the DHCPREQUEST and
receiving the DHCPACK meaning that lease is no longer in the offering
state:

"5. The client receives the DHCPACK message with configuration
    parameters.  The client SHOULD perform a final check on the
    parameters [...].  If the client detects that the address is already
    in use (e.g., through the use of ARP), the client MUST send a
    DHCPDECLINE message..."
---
 ell/dhcp-server.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ell/dhcp-server.c b/ell/dhcp-server.c
index 4c12327..0e18cf8 100644
--- a/ell/dhcp-server.c
+++ b/ell/dhcp-server.c
@@ -736,7 +736,7 @@ static void listener_event(const void *data, size_t len, void *user_data)
 		SERVER_DEBUG("Received DECLINE");
 
 		if (!server_id_opt || !server_id_match || !requested_ip_opt ||
-				!lease || !lease->offering)
+				!lease)
 			break;
 
 		if (requested_ip_opt == lease->address)
-- 
2.30.2