ctrld: usb: Add option to ignore EIDs in the config JSON

We support ignoring EIDs returned by the bridge's routing table by
supplying the `-z` parameter. This parameter is typically included in
the systemd environment file.

The above method does not work well for templated control daemon
services (such as USB) if we have the need to ignore different set of
EIDs for a given instance of the service.

Therefore, this commit adds support to supply an array of decimal EIDs
in the USB config JSON, which when supplied, will override any ignore
EIDs in the -z parameter. Since the JSON has separate sections for every
control daemon instance, this method can be used to supply unique ignore
list per instance.

Fixes JIRA https://jirasw.nvidia.com/browse/DGXOPENBMC-17580

Tested:
Tested this on HGXB300 setup by temporarily overriding the USB config
JSON as follows:

```
        "1-1-1-2": {
            "eid_type" : "static",
            "own_eid" : 8,
            "bridge_eid" : 70,
            "bridge_pool_start" : 57,
            "ignore_eids" : [58, 59, 60],
            "vendor_id" : "0x0955",
            "product_id" : "0xCF11",
            "recovery_vendor_id": "0x0955",
            "recovery_product_id": "0xCF1F",
            "reset_gpio_name": "MCU2_RST_N-O",
            "recovery_gpio_name": "MCU2_RECOV_N-O",
            "_comment" : "CX8 MCU openbmc#2: CX8_3/CX8_1"
        }
```

Then, upon restarting the specific control daemon instance:

```
May 08 10:54:20 hgxb300 systemd[1]: Started MCTP USB control daemon.
May 08 10:54:20 hgxb300 mctp-usb-ctrl 1-1-1-2[27536]: parse_command_line: No. of EIDs to ignore: 8
May 08 10:54:20 hgxb300 mctp-usb-ctrl 1-1-1-2[27536]: parse_command_line: Verbose level:1
May 08 10:54:20 hgxb300 mctp-usb-ctrl 1-1-1-2[27536]: parse_command_line: EID to ignore: 58
May 08 10:54:20 hgxb300 mctp-usb-ctrl 1-1-1-2[27536]: parse_command_line: EID to ignore: 59
May 08 10:54:20 hgxb300 mctp-usb-ctrl 1-1-1-2[27536]: parse_command_line: EID to ignore: 60
```
The EIDs to ignore get overridden to 58, 59 and 60.

The discovery output now shows:
```
root@hgxb300:~# busctl tree xyz.openbmc_project.MCTP.Control.USB1_1_1_2
`- /xyz
  `- /xyz/openbmc_project
    `- /xyz/openbmc_project/mctp
      |- /xyz/openbmc_project/mctp/0
      | |- /xyz/openbmc_project/mctp/0/57
      | `- /xyz/openbmc_project/mctp/0/70
      `- /xyz/openbmc_project/mctp/USB1_1_1_2
```

Also verified that other service instance are not impacted as they
continue to use the global ignore list.

Signed-off-by: Santosh Puranik <spuranik@nvidia.com>

Author: santoshpuranik

ctrld/mctp-ctrl.c

@@ -1332,11 +1332,6 @@ static void parse_command_line(int argc, char *const *argv,
 					sizeof(cmdline->ignore_eids[0]));
 			MCTP_CTRL_INFO("%s: No. of EIDs to ignore: %d\n",
 				       __func__, cmdline->ignore_eids_len);
-			for (int i = 0; i < cmdline->ignore_eids_len; ++i) {
-				MCTP_CTRL_INFO("%s: EID to ignore: %d\n",
-					       __func__,
-					       cmdline->ignore_eids[i]);
-			}
 			break;
 		case 'u':
 			set_uuid_str(cmdline->uuid_str, optarg, UUID_STR_LEN);
@@ -1562,6 +1557,10 @@ static void parse_command_line(int argc, char *const *argv,
 	default:
 		break;
 	}
+	for (int i = 0; i < cmdline->ignore_eids_len; ++i) {
+		MCTP_CTRL_INFO("%s: EID to ignore: %d\n", __func__,
+			       cmdline->ignore_eids[i]);
+	}
 	free(config_json_file_path);
 }
 

mctp-json.c

@@ -1142,6 +1142,37 @@ int mctp_json_usb_get_params_ctrl(mctp_cmdline_args_t *cmdline,
 		usb->perform_device_reset = json_object_get_boolean(attr);
 	}
 
+	/* Parse optional ignore_eids array */
+	attr = json_object_object_get(obj, "ignore_eids");
+	if (attr != NULL) {
+		size_t num_eids = json_object_array_length(attr);
+		size_t i;
+
+		/* Initialize ignore_eids array */
+		memset(cmdline->ignore_eids, 0, sizeof(cmdline->ignore_eids));
+		cmdline->ignore_eids_len = 0;
+
+		/* Copy valid EIDs (0-255) to the array */
+		for (i = 0; i < num_eids && i < MCTP_MAX_IGNORE_EID_LEN; i++) {
+			int eid = json_object_get_int(
+				json_object_array_get_idx(attr, i));
+			if (eid >= 0 && eid <= 255) {
+				cmdline->ignore_eids[cmdline->ignore_eids_len++] =
+					(uint8_t)eid;
+			} else {
+				MCTP_ERR(
+					"Invalid EID value %d in ignore_eids array (must be 0-255)\n",
+					eid);
+			}
+		}
+
+		if (i < num_eids) {
+			MCTP_ERR(
+				"Warning: Some ignore_eids were truncated (max %d allowed)\n",
+				MCTP_MAX_IGNORE_EID_LEN);
+		}
+	}
+
 exit:
 	json_object_put(json);
 	return rc;