module-avb: milan: aecp-aem: introducing the response to the lock-entity command

src/modules/meson.build

@@ -736,6 +736,7 @@ if build_module_avb
       'module-avb/acmp.c',
       'module-avb/aecp.c',
       'module-avb/aecp-aem.c',
+      'module-avb/aecp-aem-cmds-resps/cmd-lock-entity.c',
       'module-avb/es-builder.c',
       'module-avb/avdecc.c',
       'module-avb/maap.c',

src/modules/module-avb/aecp-aem-cmds-resps/cmd-lock-entity.c

@@ -0,0 +1,118 @@
+/* AVB support */
+/* SPDX-FileCopyrightText: Copyright © 2025 Kebag-Logic */
+/* SPDX-FileCopyrightText: Copyright © 2025 Alex Malki <alexandre.malki@kebag-logic.com> */
+/* SPDX-FileCopyrightText: Copyright © 2025 Simon Gapp <simon.gapp@kebag-logic.com> */
+/* SPDX-License-Identifier: MIT  */
+
+#include <limits.h>
+#include <inttypes.h>
+
+#include "../aecp-aem-state.h"
+#include "../descriptors.h"
+
+#include "cmd-resp-types.h"
+#include "cmd-lock-entity.h"
+#include "cmd-resp-helpers.h"
+
+
+/* LOCK_ENTITY */
+/* Milan v1.2, Sec. 5.4.2.2; IEEE 1722.1-2021, Sec. 7.4.2*/
+int handle_cmd_lock_entity_milan_v12(struct aecp *aecp, int64_t now, const void *m, int len)
+{
+	uint8_t buf[512];
+	struct server *server = aecp->server;
+	const struct avb_ethernet_header *h = m;
+	const struct avb_packet_aecp_aem *p = SPA_PTROFF(h, sizeof(*h), void);
+	const struct avb_packet_aecp_aem_lock *ae;
+
+	struct avb_ethernet_header *h_reply;
+	struct avb_packet_aecp_aem *p_reply;
+	struct avb_packet_aecp_aem_lock *ae_reply;
+
+	struct descriptor *desc;
+	struct aecp_aem_entity_milan_state *entity_state;
+	struct aecp_aem_lock_state  *lock;
+	uint16_t desc_type, desc_id;
+	bool reply_locked = false;
+	uint64_t ctrler_id;
+
+	ae = (const struct avb_packet_aecp_aem_lock*)p->payload;
+	desc_type = ntohs(ae->descriptor_type);
+	desc_id = ntohs(ae->descriptor_id);
+	ctrler_id = htobe64(p->aecp.controller_guid) ;
+
+	desc = server_find_descriptor(server, desc_type, desc_id);
+	if (desc == NULL)
+		return reply_status(aecp, AVB_AECP_AEM_STATUS_NO_SUCH_DESCRIPTOR, p, len);
+
+	entity_state = desc->ptr;
+	lock = &entity_state->lock_state;
+
+	if (desc_type != AVB_AEM_DESC_ENTITY || desc_id != 0) {
+	/*
+	 * Milan v1.2: The PAAD-AE shall not allow locking another descriptor
+	 * than the ENTITY descriptor (NOT_SUPPORTED shall be returned in
+	 * this case).
+	 */
+		return reply_not_supported(aecp, m, len);
+	}
+
+	if (ae->flags & htonl(AECP_AEM_LOCK_ENTITY_FLAG_UNLOCK)) {
+		/* Entity is not locked */
+		if (!lock->is_locked) {
+			return reply_success(aecp, m, len);
+		}
+
+		/* Unlocking by the controller which locked */
+		if (ctrler_id == lock->locked_id) {
+			pw_log_debug("Unlocking\n");
+			lock->is_locked = false;
+			lock->locked_id = 0;
+		} else {
+			/* Unlocking by a controller that did not lock?*/
+			if (ctrler_id != lock->locked_id) {
+				pw_log_debug("Already unlocked by %" PRIx64, lock->locked_id);
+				reply_locked = true;
+			} else {
+				// TODO: Can this statement be reached?
+				pw_log_error("Invalid state\n");
+				spa_assert(0);
+			}
+		}
+	} else {
+		// Is it really locked?
+		if (!lock->is_locked ||
+				lock->base_info.expire_timeout < now) {
+
+			lock->base_info.expire_timeout = now +
+				AECP_AEM_LOCK_ENTITY_EXPIRE_TIMEOUT_SECOND * SPA_NSEC_PER_SEC;
+			lock->is_locked = true;
+			lock->locked_id = ctrler_id;
+		} else {
+			// If the lock is taken again by device
+			if (ctrler_id == lock->locked_id) {
+				lock->base_info.expire_timeout +=
+					AECP_AEM_LOCK_ENTITY_EXPIRE_TIMEOUT_SECOND;
+
+				lock->is_locked = true;
+			} else {
+				// Cannot lock because already locked
+				pw_log_debug("but the device is locked by %" PRIx64, lock->locked_id);
+				reply_locked = true;
+			}
+		}
+	}
+
+	/* Forge the response for the entity that is locking the device */
+	memcpy(buf, m, len);
+	h_reply = (struct avb_ethernet_header *) buf;
+	p_reply = SPA_PTROFF(h_reply, sizeof(*h_reply), void);
+	ae_reply = (struct avb_packet_aecp_aem_lock*)p_reply->payload;
+	ae_reply->locked_guid = htobe64(lock->locked_id);
+
+	if (reply_locked) {
+		return reply_entity_locked(aecp, buf, len);
+	}
+
+	return reply_success(aecp, buf, len);
+}

src/modules/module-avb/aecp-aem-cmds-resps/cmd-lock-entity.h

@@ -0,0 +1,21 @@
+/* AVB support */
+/* SPDX-FileCopyrightText: Copyright © 2025 Kebag-Logic */
+/* SPDX-FileCopyrightText: Copyright © 2025 Alex Malki <alexandre.malki@kebag-logic.com> */
+/* SPDX-FileCopyrightText: Copyright © 2025 Simon Gapp <simon.gapp@kebag-logic.com> */
+/* SPDX-License-Identifier: MIT  */
+
+#ifndef __AVB_AECP_AEM_LOCK_H__
+#define __AVB_AECP_AEM_LOCK_H__
+
+#define AECP_AEM_LOCK_ENTITY_EXPIRE_TIMEOUT_SECOND	(60UL)
+#define AECP_AEM_LOCK_ENTITY_FLAG_UNLOCK		(1)
+
+#include <stdint.h>
+
+/**
+ * @brief Command handling will generate the response for the lock command
+ */
+int handle_cmd_lock_entity_milan_v12(struct aecp *aecp, int64_t now,
+	const void *m, int len);
+
+#endif //__AVB_AECP_AEM_LOCK_H__