Pierre-Olivier Mercier 2aa596afd5 Address publication review feedback

Add the AGPL LICENSE file and a deployment-security note in the README
to clarify that the unauthenticated /collect endpoint must run on a
trusted network.

Fix the IPv6 reachability rule so it consults the IP actually probed:
PingTargetResult now carries ResolvedIP populated from pinger.IPAddr(),
which lets the rule classify hostname targets correctly instead of
always reporting "No IPv6 target pinged".

Tighten error handling: ipsFromService now propagates JSON errors,
ExtractMetrics wraps decode failures, the count option returns an
explicit error when out of range instead of silently clamping, and the
"all pings failed" message no longer concatenates every per-target
error. Threshold validation is factored into validateThresholdPair and
shared between the RTT and packet-loss rules.

Add unit tests covering address resolution, threshold validation, and
each rule's evaluation paths.

2026-04-26 18:05:47 +07:00

3.8 KiB

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checker-ping

ICMP ping checker for happyDomain.

Checks reachability, round-trip time, and packet loss for IP addresses associated with a domain's services.

Usage

Standalone HTTP server

# Build and run
make
./checker-ping -listen :8080

# With privileged ICMP (requires CAP_NET_RAW or root)
./checker-ping -listen :8080 -privileged

The server exposes:

GET /health, health check
POST /collect, collect ping observations (happyDomain external checker protocol)

Docker

make docker
docker run -p 8080:8080 happydomain/checker-ping

# With privileged ICMP
docker run --cap-add NET_RAW -p 8080:8080 happydomain/checker-ping -privileged

happyDomain plugin

make plugin
# produces checker-ping.so, loadable by happyDomain as a Go plugin

The plugin exposes a NewCheckerPlugin symbol returning the checker definition and observation provider, which happyDomain registers in its global registries at load time.

Versioning

The binary, plugin, and Docker image embed a version string overridable at build time:

make CHECKER_VERSION=1.2.3
make plugin CHECKER_VERSION=1.2.3
make docker CHECKER_VERSION=1.2.3

happyDomain remote endpoint

Set the endpoint admin option for the ping checker to the URL of the running checker-ping server (e.g., http://checker-ping:8080). happyDomain will delegate observation collection to this endpoint.

Deployment

The /collect endpoint has no built-in authentication and will issue ICMP probes to whatever hostnames or IP addresses the caller supplies, including private (RFC 1918), loopback, link-local, and cloud metadata addresses (e.g. 169.254.169.254). It is meant to run on a trusted network, reachable only by the happyDomain instance that drives it. Restrict access via a reverse proxy with authentication, a network ACL, or by binding the listener to a private interface; do not expose it directly to the public internet.

Protocol

POST /collect

Request:

{
  "key": "ping",
  "target": {"userId": "...", "domainId": "..."},
  "options": {
    "addresses": ["1.2.3.4", "2001:db8::1"],
    "count": 5
  }
}

Response:

{
  "data": {
    "targets": [
      {
        "address": "1.2.3.4",
        "rtt_min": 1.2,
        "rtt_avg": 3.4,
        "rtt_max": 5.6,
        "packet_loss": 0,
        "sent": 5,
        "received": 5
      }
    ]
  }
}

License & licensing roadmap

This project is currently licensed under the GNU Affero General Public License v3.0 (see LICENSE), because it still imports happydns.ServiceMessage and abstract.Server from the happyDomain server module (git.happydns.org/happyDomain/model and git.happydns.org/happyDomain/services/abstract), which are themselves distributed under AGPL-3.0 and a commercial license.

The core checker types (CheckerOptions, CheckerDefinition, ObservationProvider, CheckRule, …) have already been migrated to checker-sdk-go; only the service-message types remain on the AGPL side.

Planned relicensing: as soon as the remaining ServiceMessage / abstract.Server dependency has been removed (moved into a dedicated permissively licensed module), this project will be relicensed under the MIT License, in line with the rest of the happyDomain checker ecosystem (see checker-dummy for the target shape).

Contributors notice: by submitting a contribution to this repository, you accept that your contribution will be relicensed from AGPL-3.0 to MIT at the time of the relicensing described above. If you do not agree with this, please do not submit contributions until the relicensing has taken place.

The third-party Apache-2.0 attributions for checker-sdk-go are recorded in NOTICE and must accompany any binary or source redistribution of this project.

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