tr181-agent

A small C99 tool (tr181ctl) that exposes an embedded Linux device as a TR-181 (Device:2) data model. It reads /proc and /sys/class/net, answers ubus-cli-style get/set queries, and prints USP (TR-369)-style GetResp JSON. Ships with an OpenWrt package Makefile and a Yocto recipe.

Live playground: docs/index.html (enable GitHub Pages on the docs/ folder).

Data model

Object	Access	Source
Device.DeviceInfo. (Manufacturer, ModelName, SoftwareVersion, UpTime, MemoryStatus.Total)	R	uname, /proc/uptime, /proc/meminfo
Device.Ethernet.Interface.{i}. (Name, Status, MACAddress, MaxMTUSize)	R	/sys/class/net/<if>/
Device.Ethernet.Interface.{i}.Stats. (Bytes/Packets/Errors Sent/Received)	R	/sys/class/net/<if>/statistics/
Device.ManagementServer. (URL, PeriodicInformEnable, PeriodicInformInterval)	RW	in memory, persisted to $TR181_STATE

Usage

make && make test

./tr181ctl get Device.DeviceInfo.                 # partial path -> whole object
./tr181ctl get Device.Ethernet.Interface.1.Status
./tr181ctl set Device.ManagementServer.URL https://acs.example.net
./tr181ctl json Device.DeviceInfo.                # USP-style GetResp
./tr181ctl schema                                 # every param, type, access
./tr181ctl shell                                  # interactive prompt

Example:

$ ./tr181ctl json Device.DeviceInfo.
{
  "get_resp": {
    "requested_path": "Device.DeviceInfo.",
    "err_code": 0,
    "result_params": {
        "Device.DeviceInfo.Manufacturer": "OpenSource CPE",
        "Device.DeviceInfo.UpTime": 145,
        ...
    }
  }
}

Errors follow the data model rules: unknown paths fail, read-only parameters reject set, and values are type-checked (unsignedInt, boolean, string). An invalid path in json returns USP error code 7026.

Design

• src/datamodel.c – every parameter is produced by a getter and passed to a visitor callback, so get, json, schema and state saving share one walk.
• Linux operstate is mapped to the TR-181 Status enum (Up, Down, Dormant, ...).
• src/main.c – CLI, JSON formatter, state persistence, interactive shell.

Building for a target

OpenWrt – copy packaging/openwrt/Makefile to package/tr181-agent/ in your OpenWrt tree, then make package/tr181-agent/compile.

Yocto – add packaging/yocto/tr181-agent_1.0.0.bb to your layer (point SRC_URI at this repo) and run bitbake tr181-agent.

Cross-compile by hand – make CC=aarch64-linux-gnu-gcc.

Ideas for next steps

• Register the tree on ubus (libubus) so ubus call can query it.
• Publish parameter changes over MQTT as a USP Notify.
• Add Device.IP.Interface.{i}.IPv4Address. from netlink.