mctpd: Add mctp/links/<linkName> D-Bus object

1. Create the MCTP Link D-Bus objects for the existing MCTP links at `/xyz/openbmc_project/mctp/links/<linkName>`. When the MCTP links is removed from/added to the system, the D-Bus object will also be removed/added. 2. Create the au.com.CodeConstruct.MCTP.Link D-Bus interface for MCTP Link D-Bus objects. The interface includes the `Role` property which reports BMC roles in the link. The possible value of `Role` are `BusOwner`, `Endpoint` and `Unknown`. 3. Because the BMC `Role` in the MCTP link is fixed. The `Role` property is changeable value but it can only be changed when the current configured value is `Unknown`. Ex: ``` ~# busctl tree xyz.openbmc_project.MCTP `- /xyz `- /xyz/openbmc_project `- /xyz/openbmc_project/mctp |- /xyz/openbmc_project/mctp/1 | `- /xyz/openbmc_project/mctp/1/8 `- /xyz/openbmc_project/mctp/links |- /xyz/openbmc_project/mctp/links/lo `- /xyz/openbmc_project/mctp/links/mctpi2c3 ~# busctl introspect xyz.openbmc_project.MCTP /xyz/openbmc_project/mctp/links NAME TYPE SIGNATURE RESULT/VALUE FLAGS org.freedesktop.DBus.Introspectable interface - - - .Introspect method - s - org.freedesktop.DBus.Peer interface - - - .GetMachineId method - s - .Ping method - - - org.freedesktop.DBus.Properties interface - - - .Get method ss v - .GetAll method s a{sv} - .Set method ssv - - .PropertiesChanged signal sa{sv}as - - ~# busctl introspect xyz.openbmc_project.MCTP /xyz/openbmc_project/mctp/links/mctpi2c3 NAME TYPE SIGNATURE RESULT/VALUE FLAGS au.com.CodeConstruct.MCTP.Link interface - - - .Role property s "Unknown" emits-change writable org.freedesktop.DBus.Introspectable interface - - - .Introspect method - s - org.freedesktop.DBus.Peer interface - - - .GetMachineId method - s - .Ping method - - - org.freedesktop.DBus.Properties interface - - - .Get method ss v - .GetAll method s a{sv} - .Set method ssv - - .PropertiesChanged signal sa{sv}as - - ~# busctl set-property xyz.openbmc_project.MCTP /xyz/openbmc_project/mctp/links/mctpi2c3 au.com.CodeConstruct.MCTP.Link Role s BusOwner ~# busctl set-property xyz.openbmc_project.MCTP /xyz/openbmc_project/mctp/links/mctpi2c3 au.com.CodeConstruct.MCTP.Link Role s "BusOwner" ``` Signed-off-by: Thu Nguyen <[email protected]>
CodeConstruct · May 20, 2024 · e280eed · e280eed
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 2. mctpd: Allow recovery of devices reporting a nil UUID for development
 3. mctpd: Allow configuring .Connectivity as writable for development
 4. mctpd: Add AssignEndpointStatic for static EID allocations
+5. mctpd: Add mctp/links/<linkName> D-Bus object
 
 ### Changed
 

diff --git a/docs/mctpd.md b/docs/mctpd.md
@@ -1,6 +1,6 @@
 # `mctpd`
 
-## D-Bus
+## D-Bus /xyz/openbmc_project/mctp/<NetworkId>/<EID>
 
 `mctpd` provides a D-Bus path of `/xyz/openbmc_project/mctp`. For each known MCTP endpoint, `mctpd`
 will populate an object `/xyz/openbmc_project/mctp/<NetworkId>/<EID>`. The objects have interface
@@ -89,5 +89,13 @@ busctl call xyz.openbmc_project.MCTP  /xyz/openbmc_project/mctp/1/11 \
 
 Removes the MCTP endpoint from `mctpd`, and deletes routes and neighbour entries.
 
+## D-Bus /xyz/openbmc_project/mctp/links/<InterfaceName>
+
+`mctpd` provides a D-Bus path of `/xyz/openbmc_project/mctp/links`. For each known MCTP interfaces, `mctpd`
+will populate an object `/xyz/openbmc_project/mctp/links/<InterfaceName>`.
+The objects have interface `au.com.CodeConstruct.MCTP.Link`. The interface includes the `Role` property which reports
+BMC roles in the link. The possible value of `Role` are `BusOwner`, `Endpoint` and `Unknown`.
+Because the BMC `Role` in the MCTP link is fixed. The `Role` property is changeable value but it can only be changed
+when the current configured value is `Unknown`.
 
 
diff --git a/src/mctp-netlink.c b/src/mctp-netlink.c
@@ -10,7 +10,6 @@
 
 #include <sys/socket.h>
 
-#include <linux/if.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
 #include <linux/netdevice.h>
@@ -20,33 +19,6 @@
 #include "mctp-util.h"
 #include "mctp-ops.h"
 
-struct linkmap_entry {
-	int	ifindex;
-	char	ifname[IFNAMSIZ+1];
-	int	net;
-	bool 	up;
-
-	mctp_eid_t *local_eids;
-	size_t num_local;
-};
-
-struct mctp_nl {
-	// socket for queries
-	int	sd;
-	// socket for monitor
-	int	sd_monitor;
-
-	struct linkmap_entry *linkmap;
-	size_t	linkmap_count;
-	size_t	linkmap_alloc;
-	bool	verbose;
-
-	// allows callers to silence printf of EEXIST returns.
-	// TODO: this is a workaround, if more are required we should
-	// rework how error messages are returned to callers.
-	bool quiet_eexist;
-};
-
 #define max(a, b) ((a) > (b) ? (a) : (b))
 #define min(a, b) ((a) < (b) ? (a) : (b))
 

diff --git a/src/mctp-netlink.h b/src/mctp-netlink.h
@@ -3,12 +3,53 @@
 #include <stdint.h>
 #include <stddef.h>
 #include <stdbool.h>
+#include <linux/if.h>
 #include <linux/rtnetlink.h>
 
 #include "mctp.h"
 
-struct mctp_nl;
+struct linkmap_entry {
+	int	ifindex;
+	char	ifname[IFNAMSIZ+1];
+	int	net;
+	bool 	up;
+	bool	published;
+	enum {
+		MCTP_ENTITY_ROLE_BUS_OWNER,
+		MCTP_ENTITY_ROLE_ENDPOINT,
+		MCTP_ENTITY_ROLE_UNKNOWN
+	} role;
+
+	mctp_eid_t *local_eids;
+	size_t num_local;
+};
+
+#define MCTP_ENTITY_ROLE_COUNT 3
+static const char * const role_name[] = {
+	[MCTP_ENTITY_ROLE_BUS_OWNER] = "BusOwner",
+	[MCTP_ENTITY_ROLE_ENDPOINT] = "EndPoint",
+	[MCTP_ENTITY_ROLE_UNKNOWN] = "Unknown"
+};
+
+struct mctp_nl {
+	// socket for queries
+	int	sd;
+	// socket for monitor
+	int	sd_monitor;
+
+	struct linkmap_entry *linkmap;
+	size_t	linkmap_count;
+	size_t	linkmap_alloc;
+	bool	verbose;
+
+	// allows callers to silence printf of EEXIST returns.
+	// TODO: this is a workaround, if more are required we should
+	// rework how error messages are returned to callers.
+	bool quiet_eexist;
+};
+
 typedef struct mctp_nl mctp_nl;
+typedef struct linkmap_entry linkmap_entry;
 
 struct mctp_nl_change {
 #define MCTP_NL_OP_COUNT 6