Protocols will notify when dhcpcd can exit

hooks/dhcpcd-run-hooks.8.in

@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd October 11, 2024
+.Dd October 6, 2025
 .Dt DHCPCD-RUN-HOOKS 8
 .Os
 .Sh NAME
@@ -105,6 +105,8 @@ dhcpcd renewed its lease.
 dhcpcd has rebound to a new DHCP server.
 .It Dv REBOOT | Dv REBOOT6
 dhcpcd successfully requested a lease from a DHCP server.
+.It Dv RELEASE | Dv RELEASE6
+dhcpcd has released the lease.
 .It Dv DELEGATED6
 dhcpcd assigned a delegated prefix to the interface.
 .It Dv IPV4LL

src/dhcp.c

@@ -2866,6 +2866,51 @@ dhcp_reboot(struct interface *ifp)
 	send_request(ifp);
 }
 
+static void
+dhcp_deconfigure(void *arg)
+{
+	struct interface *ifp = arg;
+	struct dhcp_state *state = D_STATE(ifp);
+	struct if_options *ifo = ifp->options;
+	const char *reason;
+
+#ifdef AUTH
+	dhcp_auth_reset(&state->auth);
+#endif
+
+	if (state->state == DHS_RELEASE)
+		reason = "RELEASE";
+	else
+		reason = state->reason;
+	state->state = DHS_NONE;
+	free(state->offer);
+	state->offer = NULL;
+	state->offer_len = 0;
+	free(state->old);
+	state->old = state->new;
+	state->old_len = state->new_len;
+	state->new = NULL;
+	state->new_len = 0;
+	if (ifo->options & DHCPCD_CONFIGURE)
+		ipv4_applyaddr(ifp);
+	else {
+		state->addr = NULL;
+		state->added = 0;
+	}
+	script_runreason(ifp, reason);
+	free(state->old);
+	state->old = NULL;
+	state->old_len = 0;
+	state->lease.addr.s_addr = 0;
+	ifo->options &= ~(DHCPCD_CSR_WARNED | DHCPCD_ROUTER_HOST_ROUTE_WARNED);
+
+	if (ifo->options & DHCPCD_STOPPING) {
+		dhcp_free(ifp);
+		dhcpcd_dropped(ifp);
+	} else
+		dhcp_close(ifp);
+}
+
 void
 dhcp_drop(struct interface *ifp, const char *reason)
 {
@@ -2876,6 +2921,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 	 * but we do have a timeout, so punt it. */
 	if (state == NULL || state->state == DHS_NONE) {
 		eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
+		dhcpcd_dropped(ifp);
 		return;
 	}
 
@@ -2886,6 +2932,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 #ifdef ARPING
 	state->arping_index = -1;
 #endif
+	state->reason = reason;
 
 	if (ifo->options & DHCPCD_RELEASE && !(ifo->options & DHCPCD_INFORM)) {
 		/* Failure to send the release may cause this function to
@@ -2899,10 +2946,21 @@ dhcp_drop(struct interface *ifp, const char *reason)
 		    state->new != NULL &&
 		    state->lease.server.s_addr != INADDR_ANY)
 		{
+			/* We need to delay removal of the IP address so the
+			 * message can be sent.
+			 * Unlike DHCPv6, there is no acknowledgement. */
+			const struct timespec delay = {
+				.tv_sec = 1,
+			};
+
 			loginfox("%s: releasing lease of %s",
 			    ifp->name, inet_ntoa(state->lease.addr));
 			dhcp_new_xid(ifp);
 			send_message(ifp, DHCP_RELEASE, NULL);
+			eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
+			eloop_timeout_add_tv(ifp->ctx->eloop,
+			    &delay, dhcp_deconfigure, ifp);
+			return;
 		}
 	}
 #ifdef AUTH
@@ -2919,36 +2977,7 @@ dhcp_drop(struct interface *ifp, const char *reason)
 #endif
 
 	eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
-#ifdef AUTH
-	dhcp_auth_reset(&state->auth);
-#endif
-
-	state->state = DHS_NONE;
-	free(state->offer);
-	state->offer = NULL;
-	state->offer_len = 0;
-	free(state->old);
-	state->old = state->new;
-	state->old_len = state->new_len;
-	state->new = NULL;
-	state->new_len = 0;
-	state->reason = reason;
-	if (ifo->options & DHCPCD_CONFIGURE)
-		ipv4_applyaddr(ifp);
-	else {
-		state->addr = NULL;
-		state->added = 0;
-		script_runreason(ifp, state->reason);
-	}
-	free(state->old);
-	state->old = NULL;
-	state->old_len = 0;
-	state->lease.addr.s_addr = 0;
-	ifo->options &= ~(DHCPCD_CSR_WARNED | DHCPCD_ROUTER_HOST_ROUTE_WARNED);
-
-	/* Close DHCP ports so a changed interface family is picked
-	 * up by a new BPF state. */
-	dhcp_close(ifp);
+	dhcp_deconfigure(ifp);
 }
 
 static int
@@ -3108,6 +3137,12 @@ dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
 #define IS_STATE_ACTIVE(s) ((s)-state != DHS_NONE && \
 	(s)->state != DHS_INIT && (s)->state != DHS_BOUND)
 
+	/* Don't do anything if the user hasn't configured it. */
+	if (ifp->active != IF_ACTIVE_USER ||
+	    ifp->options->options & DHCPCD_STOPPING ||
+	    !(ifp->options->options & DHCPCD_DHCP))
+		return;
+
 	if (bootp->op != BOOTREPLY) {
 		if (IS_STATE_ACTIVE(state))
 			logdebugx("%s: op (%d) is not BOOTREPLY",
@@ -3932,6 +3967,7 @@ dhcp_free(struct interface *ifp)
 		free(state->offer);
 		free(state->clientid);
 		free(state);
+		ifp->if_data[IF_DATA_DHCP] = NULL;
 	}
 
 	ctx = ifp->ctx;

src/dhcp6.c

@@ -2110,29 +2110,25 @@ dhcp6_startrelease(struct interface *ifp)
 	struct dhcp6_state *state;
 
 	state = D6_STATE(ifp);
-	if (state->state != DH6S_BOUND)
+	if (state->state != DH6S_BOUND) {
+		dhcp6_finishrelease(ifp);
 		return;
+	}
 
 	state->state = DH6S_RELEASE;
 	state->RTC = 0;
 	state->IMD = REL_MAX_DELAY;
 	state->IRT = REL_TIMEOUT;
 	state->MRT = REL_MAX_RT;
-	/* MRC of REL_MAX_RC is optional in RFC 3315 18.1.6 */
-#if 0
 	state->MRC = REL_MAX_RC;
 	state->MRCcallback = dhcp6_finishrelease;
-#else
-	state->MRC = 0;
-	state->MRCcallback = NULL;
-#endif
 
-	if (dhcp6_makemessage(ifp) == -1)
+	if (dhcp6_makemessage(ifp) == -1) {
 		logerr("%s: %s", __func__, ifp->name);
-	else {
-		dhcp6_sendrelease(ifp);
+		/* not much we can do apart from finish now */
 		dhcp6_finishrelease(ifp);
-	}
+	} else
+		dhcp6_sendrelease(ifp);
 }
 
 static int
@@ -3610,6 +3606,11 @@ dhcp6_recvif(struct interface *ifp, const char *sfrom,
 			    ifp->name, sfrom);
 			dhcp6_fail(ifp, true);
 			return;
+		case DH6S_RELEASE:
+			loginfox("%s: %s acknowledged RELEASE6",
+			    ifp->name, sfrom);
+			dhcp6_finishrelease(ifp);
+			return;
 		default:
 			valid_op = false;
 			break;
@@ -4293,6 +4294,7 @@ dhcp6_freedrop(struct interface *ifp, int drop, const char *reason)
 		free(state);
 		ifp->if_data[IF_DATA_DHCP6] = NULL;
 	}
+	dhcpcd_dropped(ifp);
 
 	/* If we don't have any more DHCP6 enabled interfaces,
 	 * close the global socket and release resources */