From 0406dd87753049f54b9beb7ab66f333a1d2709d2 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Tue, 11 Aug 2026 16:05:14 +0100
Subject: [PATCH] DHCP: Only send the rapid commit option when configured to

Fixes #692. Thanks to Ioannis Anagnostakis for the diagnosis.
---
 src/dhcp-common.c | 14 +++++++++++++-
 src/dhcp-common.h |  3 ++-
 src/dhcp.c        |  9 ++++-----
 src/dhcp6.c       |  8 ++++----
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/src/dhcp-common.c b/src/dhcp-common.c
index 97e80635..11c269e2 100644
--- a/src/dhcp-common.c
+++ b/src/dhcp-common.c
@@ -236,7 +236,19 @@ dho_policy_allowed(const struct dho_policy_group *pg, uint32_t option)
 }
 
 int
-dho_policy_requested(const struct dho_policy_group *pg,
+dho_policy_requested(const struct dho_policy_group *pg, uint32_t option)
+{
+	if (!dho_policy_has(&pg->dhop_request, option))
+		return 0;
+	if (dho_policy_has(&pg->dhop_allow, option))
+		return 1;
+	if (dho_policy_has(&pg->dhop_remove, option))
+		return 0;
+	return 1;
+}
+
+int
+dho_policy_opt_requested(const struct dho_policy_group *pg,
     const struct dhcp_opt *dho)
 {
 	if (dho->type & OT_NOREQ)
diff --git a/src/dhcp-common.h b/src/dhcp-common.h
index fcc974ec..23a93a0a 100644
--- a/src/dhcp-common.h
+++ b/src/dhcp-common.h
@@ -122,7 +122,8 @@ void dho_policy_group_free(struct dho_policy_group);
 int dho_policy_check(const struct dho_policy *, int (*)(uint32_t, void *),
     void *);
 
-int dho_policy_requested(const struct dho_policy_group *,
+int dho_policy_requested(const struct dho_policy_group *, uint32_t);
+int dho_policy_opt_requested(const struct dho_policy_group *,
     const struct dhcp_opt *);
 int dho_policy_removed(const struct dho_policy_group *, uint32_t);
 int dho_policy_allowed(const struct dho_policy_group *, uint32_t);
diff --git a/src/dhcp.c b/src/dhcp.c
index dc10bb0c..8e37dc09 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -975,7 +975,7 @@ make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 			    (opt->option == DHO_RENEWALTIME ||
 				opt->option == DHO_REBINDTIME))
 				continue;
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			AREA_FIT(1);
 			*p++ = (uint8_t)opt->option;
@@ -992,7 +992,7 @@ make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 			    (opt->option == DHO_RENEWALTIME ||
 				opt->option == DHO_REBINDTIME))
 				continue;
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			AREA_FIT(1);
 			*p++ = (uint8_t)opt->option;
@@ -1035,7 +1035,7 @@ make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 	}
 
 	if (type == DHCP_DISCOVER && !(ctx->options & DHCPCD_TEST) &&
-	    dho_policy_allowed(pg, DHO_RAPIDCOMMIT)) {
+	    dho_policy_requested(pg, DHO_RAPIDCOMMIT)) {
 		/* RFC 4039 Section 3 */
 		AREA_CHECK(0);
 		*p++ = DHO_RAPIDCOMMIT;
@@ -3469,8 +3469,7 @@ dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
 
 		if (state->state == DHS_DISCOVER) {
 			/* We only allow ACK of rapid commit DISCOVER. */
-			if (dho_policy_has(&pg->dhop_request,
-				DHO_RAPIDCOMMIT) &&
+			if (dho_policy_requested(pg, DHO_RAPIDCOMMIT) &&
 			    get_option(ifp->ctx, bootp, bootp_len,
 				DHO_RAPIDCOMMIT, NULL))
 				state->state = DHS_REQUEST;
diff --git a/src/dhcp6.c b/src/dhcp6.c
index 6753482a..bc8d960a 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -797,7 +797,7 @@ dhcp6_makemessage(struct interface *ifp)
 			}
 			if (n < ifo->dhcp6_override_len)
 				continue;
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			n_options++;
 			len += sizeof(o.len);
@@ -805,7 +805,7 @@ dhcp6_makemessage(struct interface *ifp)
 #ifndef SMALL
 		for (l = 0, opt = ifo->dhcp6_override;
 		    l < ifo->dhcp6_override_len; l++, opt++) {
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			n_options++;
 			len += sizeof(o.len);
@@ -1128,7 +1128,7 @@ dhcp6_makemessage(struct interface *ifp)
 			if (n < ifo->dhcp6_override_len)
 				continue;
 #endif
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			o.code = htons((uint16_t)opt->option);
 			memcpy(p, &o.code, sizeof(o.code));
@@ -1138,7 +1138,7 @@ dhcp6_makemessage(struct interface *ifp)
 #ifndef SMALL
 		for (l = 0, opt = ifo->dhcp6_override;
 		    l < ifo->dhcp6_override_len; l++, opt++) {
-			if (!dho_policy_requested(pg, opt))
+			if (!dho_policy_opt_requested(pg, opt))
 				continue;
 			o.code = htons((uint16_t)opt->option);
 			memcpy(p, &o.code, sizeof(o.code));