Add interface au.com.codeconstruct.MCTP.Bridge1

New endpoint object interface au.com.codeconstruct.MCTP.Bridge1
which will capture details of bridge type endpoint such as
pool start, pool end.

Update test framework with new test methods to validate bridge
pool assignemnt.

Signed-off-by: Faizan Ali <[email protected]>

Author: faizana-nvidia

docs/mctpd.md

@@ -219,6 +219,22 @@ busctl call au.com.codeconstruct.MCTP1 \
 
 Removes the MCTP endpoint from `mctpd`, and deletes routes and neighbour entries.
 
+### MCTP bridge interface: `au.com.codeconstruct.MCTP.Bridge1` interface
+For any endpoint which also happens to be an MCTP Bridge, if dynamic eid is
+assgined to it via d-bus method `.AssignEndpoint`, such endpoint's pool
+allocation details would be reflected into `au.com.codeconstruct.MCTP.Bridge1`
+interface of bridge's endpoint object.
+
+### `.PoolEnd`: `y`
+
+A constant property representing last EID in the contiguous range allocated
+for downstream endpoints.
+
+### `.PoolStart`: `y`
+
+A constant property representing first EID in the contiguous range allocated
+for downstream endpoints.
+
 ## Configuration
 
 `mctpd` reads configuration data from a TOML file, typically `/etc/mctpd.conf`.

src/mctpd.c

@@ -45,6 +45,7 @@
 #define MCTP_DBUS_PATH_LINKS "/au/com/codeconstruct/mctp1/interfaces"
 #define CC_MCTP_DBUS_IFACE_BUSOWNER "au.com.codeconstruct.MCTP.BusOwner1"
 #define CC_MCTP_DBUS_IFACE_ENDPOINT "au.com.codeconstruct.MCTP.Endpoint1"
+#define CC_MCTP_DBUS_IFACE_BRIDGE "au.com.codeconstruct.MCTP.Bridge1"
 #define CC_MCTP_DBUS_IFACE_TESTING "au.com.codeconstruct.MCTPTesting"
 #define MCTP_DBUS_NAME "au.com.codeconstruct.MCTP1"
 #define MCTP_DBUS_IFACE_ENDPOINT "xyz.openbmc_project.MCTP.Endpoint"
@@ -151,6 +152,7 @@ struct peer {
 	bool published;
 	sd_bus_slot *slot_obmc_endpoint;
 	sd_bus_slot *slot_cc_endpoint;
+	sd_bus_slot *slot_bridge;
 	sd_bus_slot *slot_uuid;
 	char *path;
 
@@ -256,6 +258,7 @@ static int endpoint_allocate_eid(struct peer *peer);
 
 static const sd_bus_vtable bus_endpoint_obmc_vtable[];
 static const sd_bus_vtable bus_endpoint_cc_vtable[];
+static const sd_bus_vtable bus_endpoint_bridge[];
 static const sd_bus_vtable bus_endpoint_uuid_vtable[];
 
 __attribute__((format(printf, 1, 2))) static void bug_warn(const char *fmt, ...)
@@ -1586,6 +1589,7 @@ static void free_peers(struct ctx *ctx)
 		free(peer->path);
 		sd_bus_slot_unref(peer->slot_obmc_endpoint);
 		sd_bus_slot_unref(peer->slot_cc_endpoint);
+		sd_bus_slot_unref(peer->slot_bridge);
 		sd_bus_slot_unref(peer->slot_uuid);
 		free(peer);
 	}
@@ -2668,6 +2672,8 @@ static int unpublish_peer(struct peer *peer)
 		peer->slot_obmc_endpoint = NULL;
 		sd_bus_slot_unref(peer->slot_cc_endpoint);
 		peer->slot_cc_endpoint = NULL;
+		sd_bus_slot_unref(peer->slot_bridge);
+		peer->slot_bridge = NULL;
 		sd_bus_slot_unref(peer->slot_uuid);
 		peer->slot_uuid = NULL;
 		peer->published = false;
@@ -3052,6 +3058,28 @@ static int bus_endpoint_get_prop(sd_bus *bus, const char *path,
 	return rc;
 }
 
+static int bus_bridge_get_prop(sd_bus *bus, const char *path,
+			       const char *interface, const char *property,
+			       sd_bus_message *reply, void *userdata,
+			       sd_bus_error *berr)
+{
+	struct peer *peer = userdata;
+	int rc;
+
+	if (strcmp(property, "PoolStart") == 0) {
+		rc = sd_bus_message_append(reply, "y", peer->pool_start);
+	} else if (strcmp(property, "PoolEnd") == 0) {
+		uint8_t pool_end = peer->pool_start + peer->pool_size - 1;
+		rc = sd_bus_message_append(reply, "y", pool_end);
+	} else {
+		warnx("Unknown bridge property '%s' for %s iface %s", property,
+		      path, interface);
+		rc = -ENOENT;
+	}
+
+	return rc;
+}
+
 static int bus_network_get_prop(sd_bus *bus, const char *path,
 				const char *interface, const char *property,
 				sd_bus_message *reply, void *userdata,
@@ -3251,6 +3279,21 @@ static const sd_bus_vtable bus_endpoint_cc_vtable[] = {
 	SD_BUS_VTABLE_END
 };
 
+static const sd_bus_vtable bus_endpoint_bridge[] = {
+	SD_BUS_VTABLE_START(0),
+	SD_BUS_PROPERTY("PoolStart",
+			"y",
+			bus_bridge_get_prop,
+			0,
+			SD_BUS_VTABLE_PROPERTY_CONST),
+	SD_BUS_PROPERTY("PoolEnd",
+			"y",
+			bus_bridge_get_prop,
+			0,
+			SD_BUS_VTABLE_PROPERTY_CONST),
+	SD_BUS_VTABLE_END
+};
+
 static const sd_bus_vtable bus_link_vtable[] = {
 	SD_BUS_VTABLE_START(0),
 	SD_BUS_WRITABLE_PROPERTY("Role",
@@ -4346,6 +4389,18 @@ static int endpoint_allocate_eid(struct peer *peer)
 					return rc;
 				}
 			}
+			sd_bus_add_object_vtable(peer->ctx->bus,
+						 &peer->slot_bridge, peer->path,
+						 CC_MCTP_DBUS_IFACE_BRIDGE,
+						 bus_endpoint_bridge, peer);
+			rc = sd_bus_emit_interfaces_added(
+				peer->ctx->bus, peer->path,
+				CC_MCTP_DBUS_IFACE_BRIDGE, NULL);
+			if (rc < 0) {
+				warnx("Failed to emit add %s signal for endpoint %d : %s",
+				      CC_MCTP_DBUS_IFACE_BRIDGE, peer->eid,
+				      strerror(-rc));
+			}
 			// TODO: Polling logic for downstream EID
 		}
 	}

tests/test_mctpd.py

@@ -20,6 +20,7 @@
 MCTPD_MCTP_P = '/au/com/codeconstruct/mctp1'
 MCTPD_MCTP_I = 'au.com.codeconstruct.MCTP.BusOwner1'
 MCTPD_ENDPOINT_I = 'au.com.codeconstruct.MCTP.Endpoint1'
+MCTPD_ENDPOINT_BRIDGE_I = 'au.com.codeconstruct.MCTP.Bridge1'
 DBUS_OBJECT_MANAGER_I = 'org.freedesktop.DBus.ObjectManager'
 DBUS_PROPERTIES_I = 'org.freedesktop.DBus.Properties'
 
@@ -964,4 +965,126 @@ async def test_assign_dynamic_bridge_eid(dbus, mctpd):
     with pytest.raises(asyncdbus.errors.DBusError) as ex:
         await mctp.call_assign_endpoint_static(dev2.lladdr, ep.eid + 1)
 
-    assert str(ex.value) == "EID belongs to another MCTP bridge pool"
+    assert str(ex.value) == "EID belongs to another MCTP bridge pool"
+
+""" Test that we truncate the requested pool size to
+    the max_pool_size config """
+async def test_assign_dynamic_eid_limited_pool(nursery, dbus, sysnet):
+    max_pool_size = 1
+    config = f"""
+    [bus-owner]
+    max_pool_size = {max_pool_size}
+    """
+
+    mctpd = MctpdWrapper(dbus, sysnet, config = config)
+    await mctpd.start_mctpd(nursery)
+
+    iface = mctpd.system.interfaces[0]
+    ep = mctpd.network.endpoints[0]
+    mctp = await mctpd_mctp_iface_obj(dbus, iface)
+
+    # Set up bridged endpoints as undiscovered EID 0
+    for i in range(0, 2):
+        br_ep = Endpoint(iface, bytes(), types=[0, 2])
+        ep.add_bridged_ep(br_ep)
+        mctpd.network.add_endpoint(br_ep)
+
+    # dynamic EID assigment for dev1
+    (eid, _, path, new) = await mctp.call_assign_endpoint(
+        ep.lladdr,
+    )
+
+    assert new
+
+    bridge_obj = await dbus.get_proxy_object(MCTPD_C, path)
+    props_iface = await bridge_obj.get_interface(DBUS_PROPERTIES_I)
+    pool_end = await props_iface.call_get(MCTPD_ENDPOINT_BRIDGE_I, "PoolEnd")
+    pool_size = pool_end.value - eid
+    assert pool_size == max_pool_size
+
+    res = await mctpd.stop_mctpd()
+    assert res == 0
+
+""" Test that no pool is assigned for requested pool size from
+    unavailable pool space"""
+async def test_assign_dynamic_unavailable_pool(nursery, dbus, sysnet):
+    (min_dyn_eid, max_dyn_eid) = (8, 12)
+    config = f"""
+    [bus-owner]
+    dynamic_eid_range = [{min_dyn_eid}, {max_dyn_eid}]
+    """
+
+    mctpd = MctpdWrapper(dbus, sysnet, config = config)
+    await mctpd.start_mctpd(nursery)
+
+    iface = mctpd.system.interfaces[0]
+    ep = mctpd.network.endpoints[0]
+    mctp = await mctpd_mctp_iface_obj(dbus, iface)
+
+    # Set up bridged endpoints as undiscovered EID 0
+    for i in range(0, 2):
+        br_ep = Endpoint(iface, bytes(), types=[0, 2])
+        ep.add_bridged_ep(br_ep)
+        mctpd.network.add_endpoint(br_ep)
+
+    # consume middle eid from the range to dev2
+    dev2 = Endpoint(iface, bytes([0x09]))
+    mctpd.network.add_endpoint(dev2)
+    (eid, _, path, new) = await mctp.call_assign_endpoint_static(
+        dev2.lladdr,
+        10
+    )
+    assert new
+
+    # dynamic EID assigment for dev1
+    (eid, _, path, new) = await mctp.call_assign_endpoint(
+        ep.lladdr,
+    )
+    assert new
+    # Interface should not be present for unavailable pool space
+    with pytest.raises(asyncdbus.errors.InterfaceNotFoundError):
+        bridge_obj = await dbus.get_proxy_object(MCTPD_C, path)
+        await bridge_obj.get_interface(MCTPD_ENDPOINT_BRIDGE_I)
+
+    res = await mctpd.stop_mctpd()
+    assert res == 0
+
+"""During Allocate Endpoint ID exchange, return completion code failure
+to indicate no pool has been assigned to the bridge"""
+async def test_assign_dynamic_eid_allocation_failure(dbus, mctpd):
+    class BridgeEndpoint(Endpoint):
+        async def handle_mctp_control(self, sock, src_addr, msg):
+            flags, opcode = msg[0:2]
+            if opcode != 0x8:
+                return await super().handle_mctp_control(sock, src_addr, msg)
+            dst_addr = MCTPSockAddr.for_ep_resp(self, src_addr, sock.addr_ext)
+
+            msg = bytes([
+                flags & 0x1f, # Rsp
+                0x08, # opcode: Allocate Endpoint ID
+                0x01, # cc: failure
+                0x01, # allocation rejected
+                0x00, # pool size
+                0x00, # pool start
+            ])
+            await sock.send(dst_addr, msg)
+
+    iface = mctpd.system.interfaces[0]
+    ep = BridgeEndpoint(iface, bytes([0x1e]))
+    mctpd.network.add_endpoint(ep)
+    # Set up downstream endpoints as undiscovered EID 0
+    for i in range(0, 2):
+        br_ep = Endpoint(iface, bytes(), types=[0, 2])
+        ep.add_bridged_ep(br_ep)
+        mctpd.network.add_endpoint(br_ep)
+    mctp = await mctpd_mctp_iface_obj(dbus, iface)
+
+    # dynamic EID assigment for dev1
+    (eid, _, path, new) = await mctp.call_assign_endpoint(
+        ep.lladdr,
+    )
+    assert new
+    # Interface should not be present for failed pool allocation
+    with pytest.raises(asyncdbus.errors.InterfaceNotFoundError):
+        bridge_obj = await dbus.get_proxy_object(MCTPD_C, path)
+        await bridge_obj.get_interface(MCTPD_ENDPOINT_BRIDGE_I)