From d43fc12306c7e47ffe0edcf289a8bfc853e0d4bd Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Sun, 28 Aug 2022 03:40:59 -0400
Subject: [PATCH] Advance the xid after we consume a DHCPACK or DHCPNAK.

This isn't strictly required by the RFC but it is good practice.
---
 state.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/state.c b/state.c
index 7c6d586..91d428f 100644
--- a/state.c
+++ b/state.c
@@ -223,6 +223,7 @@ static int extend_packet(struct client_state_t *cs,
                       clibuf, sizeof clibuf);
             log_line("%s: Server is now offering IP %s.  Validating...",
                      client_config.interface, clibuf);
+            cs->xid = nk_random_u32(&cs->rnd_state);
             return ANP_CHECK_IP;
         } else {
             log_line("%s: Lease refreshed to %u seconds.",
@@ -231,6 +232,7 @@ static int extend_packet(struct client_state_t *cs,
                 log_line("%s: Failed to create ARP defense socket.",
                          client_config.interface);
             stop_dhcp_listen(cs);
+            cs->xid = nk_random_u32(&cs->rnd_state);
             return ANP_SUCCESS;
         }
     } else if (msgtype == DHCPNAK) {