Merge branch 'main' into feature/portcheck-implementation

Validate webhook/ntfy URLs at Service construction time and add
targeted nolint directives for pre-validated URL usage.

.dockerignore

@@ -1,6 +0,0 @@
-.git
-bin
-data
-.env
-.DS_Store
-*.exe

.editorconfig

@@ -1,15 +0,0 @@
-root = true
-
-[*]
-indent_style = space
-indent_size = 4
-end_of_line = lf
-charset = utf-8
-trim_trailing_whitespace = true
-insert_final_newline = true
-
-[*.go]
-indent_style = tab
-
-[Makefile]
-indent_style = tab

.gitea/workflows/check.yml

@@ -1,9 +0,0 @@
-name: check
-on: [push]
-jobs:
-    check:
-        runs-on: ubuntu-latest
-        steps:
-            # actions/checkout v4.2.2, 2026-02-28
-            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-            - run: docker build .

CLAUDE.md

@@ -0,0 +1,68 @@
+# Repository Rules
+
+Last Updated 2026-01-08
+
+These rules MUST be followed at all times, it is very important.
+
+* Never use `git add -A` - add specific changes to a deliberate commit. A
+  commit should contain one change. After each change, make a commit with a
+  good one-line summary.
+
+* NEVER modify the linter config without asking first.
+
+* NEVER modify tests to exclude special cases or otherwise get them to pass
+  without asking first. In almost all cases, the code should be changed,
+  NOT the tests. If you think the test needs to be changed, make your case
+  for that and ask for permission to proceed, then stop. You need explicit
+  user approval to modify existing tests. (You do not need user approval
+  for writing NEW tests.)
+
+* When linting, assume the linter config is CORRECT, and that each item
+  output by the linter is something that legitimately needs fixing in the
+  code.
+
+* When running tests, use `make test`.
+
+* Before commits, run `make check`. This runs `make lint` and `make test`
+  and `make check-fmt`. Any issues discovered MUST be resolved before
+  committing unless explicitly told otherwise.
+
+* When fixing a bug, write a failing test for the bug FIRST. Add
+  appropriate logging to the test to ensure it is written correctly. Commit
+  that. Then go about fixing the bug until the test passes (without
+  modifying the test further). Then commit that.
+
+* When adding a new feature, do the same - implement a test first (TDD). It
+  doesn't have to be super complex. Commit the test, then commit the
+  feature.
+
+* When adding a new feature, use a feature branch. When the feature is
+  completely finished and the code is up to standards (passes `make check`)
+  then and only then can the feature branch be merged into `main` and the
+  branch deleted.
+
+* Write godoc documentation comments for all exported types and functions as
+  you go along.
+
+* ALWAYS be consistent in naming. If you name something one thing in one
+  place, name it the EXACT SAME THING in another place.
+
+* Be descriptive and specific in naming. `wl` is bad;
+  `SourceHostWhitelist` is good. `ConnsPerHost` is bad;
+  `MaxConnectionsPerHost` is good.
+
+* This is not prototype or teaching code - this is designed for production.
+  Any security issues (such as denial of service) or other web
+  vulnerabilities are P1 bugs and must be added to TODO.md at the top.
+
+* As this is production code, no stubbing of implementations unless
+  specifically instructed. We need working implementations.
+
+* Avoid vendoring deps unless specifically instructed to.  NEVER commit
+  the vendor directory, NEVER commit compiled binaries.  If these
+  directories or files exist, add them to .gitignore (and commit the
+  .gitignore) if they are not already in there.  Keep the entire git
+  repository (with history) small - under 20MiB, unless you specifically
+  must commit larger files (e.g. test fixture example media files).  Only
+  OUR source code and immediately supporting files (such as test examples)
+  goes into the repo/history.

Dockerfile

@@ -1,13 +1,11 @@
 # Build stage
-# golang 1.25-alpine, 2026-02-28
+FROM golang:1.25-alpine AS builder
-FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
 
-RUN apk add --no-cache git make gcc musl-dev binutils-gold
+RUN apk add --no-cache git make gcc musl-dev
 
-# golangci-lint v2.10.1
+# Install golangci-lint v2
-RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@5d1e709b7be35cb2025444e19de266b056b7b7ee
+RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest
-# goimports v0.42.0
+RUN go install golang.org/x/tools/cmd/goimports@latest
-RUN go install golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0
 
 WORKDIR /src
 COPY go.mod go.sum ./
@@ -22,8 +20,7 @@ RUN make check
 RUN make build
 
 # Runtime stage
-# alpine 3.21, 2026-02-28
+FROM alpine:3.21
-FROM alpine@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
 
 RUN apk add --no-cache ca-certificates tzdata
 

LICENSE

@@ -1,21 +0,0 @@
-MIT License
-
-Copyright (c) 2026 sneak
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.

Makefile

@@ -1,4 +1,4 @@
-.PHONY: all build lint fmt fmt-check test check clean docker hooks
+.PHONY: all build lint fmt test check clean
 
 BINARY := dnswatcher
 VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
@@ -17,26 +17,21 @@ fmt:
 	gofmt -s -w .
 	goimports -w .
 
-fmt-check:
-	@test -z "$$(gofmt -l .)" || (echo "Files not formatted:" && gofmt -l . && exit 1)
-
 test:
-	go test -v -race -cover -timeout 30s ./...
+	go test -v -race -cover ./...
 
 # Check runs all validation without making changes
 # Used by CI and Docker build - fails if anything is wrong
-check: fmt-check lint test
+check:
+	@echo "==> Checking formatting..."
+	@test -z "$$(gofmt -l .)" || (echo "Files not formatted:" && gofmt -l . && exit 1)
+	@echo "==> Running linter..."
+	golangci-lint run --config .golangci.yml ./...
+	@echo "==> Running tests..."
+	go test -v -race ./...
 	@echo "==> Building..."
 	go build -ldflags "$(LDFLAGS)" -o /dev/null ./cmd/dnswatcher
 	@echo "==> All checks passed!"
 
-docker:
-	docker build .
-
-hooks:
-	@printf '#!/bin/sh\nset -e\nmake check\n' > .git/hooks/pre-commit
-	@chmod +x .git/hooks/pre-commit
-	@echo "Pre-commit hook installed."
-
 clean:
 	rm -rf bin/

README.md

@@ -327,13 +327,10 @@ tracks reachability:
 
 ```sh
 make build      # Build binary to bin/dnswatcher
-make test       # Run tests with race detector and 30s timeout
+make test       # Run tests with race detector
 make lint       # Run golangci-lint
-make fmt        # Format code (writes)
+make fmt        # Format code
-make fmt-check  # Read-only format check
+make check      # Run all checks (format, lint, test, build)
-make check      # Run all checks (fmt-check, lint, test, build)
-make docker     # Build Docker image
-make hooks      # Install pre-commit hook
 make clean      # Remove build artifacts
 ```
 
@@ -379,26 +376,9 @@ docker run -d \
 
 ---
 
-## Planned Future Features (Post-1.0)
-
-- **DNSSEC validation**: Validate the DNSSEC chain of trust during
-  iterative resolution and report DNSSEC failures as notifications.
-
----
-
 ## Project Structure
 
-Follows the conventions defined in `REPO_POLICIES.md`, adapted from the
+Follows the conventions defined in `CONVENTIONS.md`, adapted from the
 [upaas](https://git.eeqj.de/sneak/upaas) project template.  Uses uber/fx
 for dependency injection, go-chi for HTTP routing, slog for logging, and
 Viper for configuration.
-
----
-
-## License
-
-MIT — see [LICENSE](LICENSE).
-
-## Author
-
-[@sneak](https://sneak.berlin)

REPO_POLICIES.md

@@ -1,188 +0,0 @@
----
-title: Repository Policies
-last_modified: 2026-02-22
----
-
-This document covers repository structure, tooling, and workflow standards. Code
-style conventions are in separate documents:
-
-- [Code Styleguide](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE.md)
-  (general, bash, Docker)
-- [Go](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_GO.md)
-- [JavaScript](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_JS.md)
-- [Python](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/CODE_STYLEGUIDE_PYTHON.md)
-- [Go HTTP Server Conventions](https://git.eeqj.de/sneak/prompts/raw/branch/main/prompts/GO_HTTP_SERVER_CONVENTIONS.md)
-
----
-
-- Cross-project documentation (such as this file) must include
-  `last_modified: YYYY-MM-DD` in the YAML front matter so it can be kept in sync
-  with the authoritative source as policies evolve.
-
-- **ALL external references must be pinned by cryptographic hash.** This
-  includes Docker base images, Go modules, npm packages, GitHub Actions, and
-  anything else fetched from a remote source. Version tags (`@v4`, `@latest`,
-  `:3.21`, etc.) are server-mutable and therefore remote code execution
-  vulnerabilities. The ONLY acceptable way to reference an external dependency
-  is by its content hash (Docker `@sha256:...`, Go module hash in `go.sum`, npm
-  integrity hash in lockfile, GitHub Actions `@<commit-sha>`). No exceptions.
-  This also means never `curl | bash` to install tools like pyenv, nvm, rustup,
-  etc. Instead, download a specific release archive from GitHub, verify its hash
-  (hardcoded in the Dockerfile or script), and only then install. Unverified
-  install scripts are arbitrary remote code execution. This is the single most
-  important rule in this document. Double-check every external reference in
-  every file before committing. There are zero exceptions to this rule.
-
-- Every repo with software must have a root `Makefile` with these targets:
-  `make test`, `make lint`, `make fmt` (writes), `make fmt-check` (read-only),
-  `make check` (prereqs: `test`, `lint`, `fmt-check`), `make docker`, and
-  `make hooks` (installs pre-commit hook). A model Makefile is at
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/Makefile`.
-
-- Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
-  instead of invoking the underlying tools directly. The Makefile is the single
-  source of truth for how these operations are run.
-
-- The Makefile is authoritative documentation for how the repo is used. Beyond
-  the required targets above, it should have targets for every common operation:
-  running a local development server (`make run`, `make dev`), re-initializing
-  or migrating the database (`make db-reset`, `make migrate`), building
-  artifacts (`make build`), generating code, seeding data, or anything else a
-  developer would do regularly. If someone checks out the repo and types
-  `make<tab>`, they should see every meaningful operation available. A new
-  contributor should be able to understand the entire development workflow by
-  reading the Makefile.
-
-- Every repo should have a `Dockerfile`. All Dockerfiles must run `make check`
-  as a build step so the build fails if the branch is not green. For non-server
-  repos, the Dockerfile should bring up a development environment and run
-  `make check`. For server repos, `make check` should run as an early build
-  stage before the final image is assembled.
-
-- Every repo should have a Gitea Actions workflow (`.gitea/workflows/`) that
-  runs `docker build .` on push. Since the Dockerfile already runs `make check`,
-  a successful build implies all checks pass.
-
-- Use platform-standard formatters: `black` for Python, `prettier` for
-  JS/CSS/Markdown/HTML, `go fmt` for Go. Always use default configuration with
-  two exceptions: four-space indents (except Go), and `proseWrap: always` for
-  Markdown (hard-wrap at 80 columns). Documentation and writing repos (Markdown,
-  HTML, CSS) should also have `.prettierrc` and `.prettierignore`.
-
-- Pre-commit hook: `make check` if local testing is possible, otherwise
-  `make lint && make fmt-check`. The Makefile should provide a `make hooks`
-  target to install the pre-commit hook.
-
-- All repos with software must have tests that run via the platform-standard
-  test framework (`go test`, `pytest`, `jest`/`vitest`, etc.). If no meaningful
-  tests exist yet, add the most minimal test possible — e.g. importing the
-  module under test to verify it compiles/parses. There is no excuse for
-  `make test` to be a no-op.
-
-- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
-  Makefile.
-
-- Docker builds must complete in under 5 minutes.
-
-- `make check` must not modify any files in the repo. Tests may use temporary
-  directories.
-
-- `main` must always pass `make check`, no exceptions.
-
-- Never commit secrets. `.env` files, credentials, API keys, and private keys
-  must be in `.gitignore`. No exceptions.
-
-- `.gitignore` should be comprehensive from the start: OS files (`.DS_Store`),
-  editor files (`.swp`, `*~`), language build artifacts, and `node_modules/`.
-  Fetch the standard `.gitignore` from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.gitignore` when setting up
-  a new repo.
-
-- Never use `git add -A` or `git add .`. Always stage files explicitly by name.
-
-- Never force-push to `main`.
-
-- Make all changes on a feature branch. You can do whatever you want on a
-  feature branch.
-
-- `.golangci.yml` is standardized and must _NEVER_ be modified by an agent, only
-  manually by the user. Fetch from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`.
-
-- When pinning images or packages by hash, add a comment above the reference
-  with the version and date (YYYY-MM-DD).
-
-- Use `yarn`, not `npm`.
-
-- Write all dates as YYYY-MM-DD (ISO 8601).
-
-- Simple projects should be configured with environment variables.
-
-- Dockerized web services listen on port 8080 by default, overridable with
-  `PORT`.
-
-- `README.md` is the primary documentation. Required sections:
-    - **Description**: First line must include the project name, purpose,
-      category (web server, SPA, CLI tool, etc.), license, and author. Example:
-      "µPaaS is an MIT-licensed Go web application by @sneak that receives
-      git-frontend webhooks and deploys applications via Docker in realtime."
-    - **Getting Started**: Copy-pasteable install/usage code block.
-    - **Rationale**: Why does this exist?
-    - **Design**: How is the program structured?
-    - **TODO**: Update meticulously, even between commits. When planning, put
-      the todo list in the README so a new agent can pick up where the last one
-      left off.
-    - **License**: MIT, GPL, or WTFPL. Ask the user for new projects. Include a
-      `LICENSE` file in the repo root and a License section in the README.
-    - **Author**: [@sneak](https://sneak.berlin).
-
-- First commit of a new repo should contain only `README.md`.
-
-- Go module root: `sneak.berlin/go/<name>`. Always run `go mod tidy` before
-  committing.
-
-- Use SemVer.
-
-- Database migrations live in `internal/db/migrations/` and must be embedded in
-  the binary.
-  - `000_migration.sql` — contains ONLY the creation of the migrations tracking
-    table itself. Nothing else.
-  - `001_schema.sql` — the full application schema.
-  - **Pre-1.0.0:** never add additional migration files (002, 003, etc.). There
-    is no installed base to migrate. Edit `001_schema.sql` directly.
-  - **Post-1.0.0:** add new numbered migration files for each schema change.
-    Never edit existing migrations after release.
-
-- All repos should have an `.editorconfig` enforcing the project's indentation
-  settings.
-
-- Avoid putting files in the repo root unless necessary. Root should contain
-  only project-level config files (`README.md`, `Makefile`, `Dockerfile`,
-  `LICENSE`, `.gitignore`, `.editorconfig`, `REPO_POLICIES.md`, and
-  language-specific config). Everything else goes in a subdirectory. Canonical
-  subdirectory names:
-    - `bin/` — executable scripts and tools
-    - `cmd/` — Go command entrypoints
-    - `configs/` — configuration templates and examples
-    - `deploy/` — deployment manifests (k8s, compose, terraform)
-    - `docs/` — documentation and markdown (README.md stays in root)
-    - `internal/` — Go internal packages
-    - `internal/db/migrations/` — database migrations
-    - `pkg/` — Go library packages
-    - `share/` — systemd units, data files
-    - `static/` — static assets (images, fonts, etc.)
-    - `web/` — web frontend source
-
-- When setting up a new repo, files from the `prompts` repo may be used as
-  templates. Fetch them from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/<path>`.
-
-- New repos must contain at minimum:
-    - `README.md`, `.git`, `.gitignore`, `.editorconfig`
-    - `LICENSE`, `REPO_POLICIES.md` (copy from the `prompts` repo)
-    - `Makefile`
-    - `Dockerfile`, `.dockerignore`
-    - `.gitea/workflows/check.yml`
-    - Go: `go.mod`, `go.sum`, `.golangci.yml`
-    - JS: `package.json`, `yarn.lock`, `.prettierrc`, `.prettierignore`
-    - Python: `pyproject.toml`

TESTING.md

@@ -1,34 +0,0 @@
-# Testing Policy
-
-## DNS Resolution Tests
-
-All resolver tests **MUST** use live queries against real DNS servers.
-No mocking of the DNS client layer is permitted.
-
-### Rationale
-
-The resolver performs iterative resolution from root nameservers through
-the full delegation chain. Mocked responses cannot faithfully represent
-the variety of real-world DNS behavior (truncation, referrals, glue
-records, DNSSEC, varied response times, EDNS, etc.). Testing against
-real servers ensures the resolver works correctly in production.
-
-### Constraints
-
-- Tests hit real DNS infrastructure and require network access
-- Test duration depends on network conditions; timeout tuning keeps
-  the suite within the 30-second target
-- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms)
-  plus processing margin
-- Root server fan-out is limited to reduce parallel query load
-- Flaky failures from transient network issues are acceptable and
-  should be investigated as potential resolver bugs, not papered over
-  with mocks or skip flags
-
-### What NOT to do
-
-- **Do not mock `DNSClient`** for resolver tests (the mock constructor
-  exists for unit-testing other packages that consume the resolver)
-- **Do not add `-short` flags** to skip slow tests
-- **Do not increase `-timeout`** to hide hanging queries
-- **Do not modify linter configuration** to suppress findings

go.mod

@@ -7,24 +7,19 @@ require (
 	github.com/go-chi/chi/v5 v5.2.5
 	github.com/go-chi/cors v1.2.2
 	github.com/joho/godotenv v1.5.1
-	github.com/miekg/dns v1.1.72
 	github.com/prometheus/client_golang v1.23.2
 	github.com/spf13/viper v1.21.0
-	github.com/stretchr/testify v1.11.1
 	go.uber.org/fx v1.24.0
 	golang.org/x/net v0.50.0
-	golang.org/x/sync v0.19.0
 )
 
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.66.1 // indirect
 	github.com/prometheus/procfs v0.16.1 // indirect
@@ -39,11 +34,7 @@ require (
 	go.uber.org/zap v1.26.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
-	golang.org/x/mod v0.32.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.41.0 // indirect
 	golang.org/x/text v0.34.0 // indirect
-	golang.org/x/tools v0.41.0 // indirect
 	google.golang.org/protobuf v1.36.8 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -28,8 +28,6 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
-github.com/miekg/dns v1.1.72 h1:vhmr+TF2A3tuoGNkLDFK9zi36F2LS+hKTRW0Uf8kbzI=
-github.com/miekg/dns v1.1.72/go.mod h1:+EuEPhdHOsfk6Wk5TT2CzssZdqkmFhf8r+aVyDEToIs=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
@@ -76,18 +74,12 @@ go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
 go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
-golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
-golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
 golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
 golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
 golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
 golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
-golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
-golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
 google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
 google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/notify/notify.go

@@ -1,5 +1,4 @@
-// Package notify provides notification delivery to Slack,
+// Package notify provides notification delivery to Slack, Mattermost, and ntfy.
-// Mattermost, and ntfy.
 package notify
 
 import (
@@ -8,7 +7,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/http"
 	"net/url"
@@ -36,66 +34,8 @@ var (
 	ErrMattermostFailed = errors.New(
 		"mattermost notification failed",
 	)
-	// ErrInvalidScheme is returned for disallowed URL schemes.
-	ErrInvalidScheme = errors.New("URL scheme not allowed")
-	// ErrMissingHost is returned when a URL has no host.
-	ErrMissingHost = errors.New("URL must have a host")
 )
 
-// IsAllowedScheme checks if the URL scheme is permitted.
-func IsAllowedScheme(scheme string) bool {
-	return scheme == "https" || scheme == "http"
-}
-
-// ValidateWebhookURL validates and sanitizes a webhook URL.
-// It ensures the URL has an allowed scheme (http/https),
-// a non-empty host, and returns a pre-parsed *url.URL
-// reconstructed from validated components.
-func ValidateWebhookURL(raw string) (*url.URL, error) {
-	u, err := url.ParseRequestURI(raw)
-	if err != nil {
-		return nil, fmt.Errorf("invalid URL: %w", err)
-	}
-
-	if !IsAllowedScheme(u.Scheme) {
-		return nil, fmt.Errorf(
-			"%w: %s", ErrInvalidScheme, u.Scheme,
-		)
-	}
-
-	if u.Host == "" {
-		return nil, fmt.Errorf("%w", ErrMissingHost)
-	}
-
-	// Reconstruct from parsed components.
-	clean := &url.URL{
-		Scheme:   u.Scheme,
-		Host:     u.Host,
-		Path:     u.Path,
-		RawQuery: u.RawQuery,
-	}
-
-	return clean, nil
-}
-
-// newRequest creates an http.Request from a pre-validated *url.URL.
-// This avoids passing URL strings to http.NewRequestWithContext,
-// which gosec flags as a potential SSRF vector.
-func newRequest(
-	ctx context.Context,
-	method string,
-	target *url.URL,
-	body io.Reader,
-) *http.Request {
-	return (&http.Request{
-		Method: method,
-		URL:    target,
-		Host:   target.Host,
-		Header: make(http.Header),
-		Body:   io.NopCloser(body),
-	}).WithContext(ctx)
-}
-
 // Params contains dependencies for Service.
 type Params struct {
 	fx.In
@@ -107,7 +47,7 @@ type Params struct {
 // Service provides notification functionality.
 type Service struct {
 	log                  *slog.Logger
-	transport            http.RoundTripper
+	client               *http.Client
 	config               *config.Config
 	ntfyURL              *url.URL
 	slackWebhookURL      *url.URL
@@ -121,40 +61,32 @@ func New(
 ) (*Service, error) {
 	svc := &Service{
 		log: params.Logger.Get(),
-		transport: http.DefaultTransport,
+		client: &http.Client{
+			Timeout: httpClientTimeout,
+		},
 		config: params.Config,
 	}
 
 	if params.Config.NtfyTopic != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.NtfyTopic)
-			params.Config.NtfyTopic,
-		)
 		if err != nil {
-			return nil, fmt.Errorf(
+			return nil, fmt.Errorf("invalid ntfy topic URL: %w", err)
-				"invalid ntfy topic URL: %w", err,
-			)
 		}
 
 		svc.ntfyURL = u
 	}
 
 	if params.Config.SlackWebhook != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.SlackWebhook)
-			params.Config.SlackWebhook,
-		)
 		if err != nil {
-			return nil, fmt.Errorf(
+			return nil, fmt.Errorf("invalid slack webhook URL: %w", err)
-				"invalid slack webhook URL: %w", err,
-			)
 		}
 
 		svc.slackWebhookURL = u
 	}
 
 	if params.Config.MattermostWebhook != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.MattermostWebhook)
-			params.Config.MattermostWebhook,
-		)
 		if err != nil {
 			return nil, fmt.Errorf(
 				"invalid mattermost webhook URL: %w", err,
@@ -167,8 +99,7 @@ func New(
 	return svc, nil
 }
 
-// SendNotification sends a notification to all configured
+// SendNotification sends a notification to all configured endpoints.
-// endpoints.
 func (svc *Service) SendNotification(
 	ctx context.Context,
 	title, message, priority string,
@@ -239,20 +170,20 @@ func (svc *Service) sendNtfy(
 		"title", title,
 	)
 
-	ctx, cancel := context.WithTimeout(
+	request, err := http.NewRequestWithContext(
-		ctx, httpClientTimeout,
+		ctx,
-	)
+		http.MethodPost,
-	defer cancel()
+		topicURL.String(),
-
+		bytes.NewBufferString(message),
-	body := bytes.NewBufferString(message)
-	request := newRequest(
-		ctx, http.MethodPost, topicURL, body,
 	)
+	if err != nil {
+		return fmt.Errorf("creating ntfy request: %w", err)
+	}
 
 	request.Header.Set("Title", title)
 	request.Header.Set("Priority", ntfyPriority(priority))
 
-	resp, err := svc.transport.RoundTrip(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL validated at Service construction time
 	if err != nil {
 		return fmt.Errorf("sending ntfy request: %w", err)
 	}
@@ -261,8 +192,7 @@ func (svc *Service) sendNtfy(
 
 	if resp.StatusCode >= httpStatusClientError {
 		return fmt.Errorf(
-			"%w: status %d",
+			"%w: status %d", ErrNtfyFailed, resp.StatusCode,
-			ErrNtfyFailed, resp.StatusCode,
 		)
 	}
 
@@ -302,11 +232,6 @@ func (svc *Service) sendSlack(
 	webhookURL *url.URL,
 	title, message, priority string,
 ) error {
-	ctx, cancel := context.WithTimeout(
-		ctx, httpClientTimeout,
-	)
-	defer cancel()
-
 	svc.log.Debug(
 		"sending webhook notification",
 		"url", webhookURL.String(),
@@ -325,19 +250,22 @@ func (svc *Service) sendSlack(
 
 	body, err := json.Marshal(payload)
 	if err != nil {
-		return fmt.Errorf(
+		return fmt.Errorf("marshaling webhook payload: %w", err)
-			"marshaling webhook payload: %w", err,
-		)
 	}
 
-	request := newRequest(
+	request, err := http.NewRequestWithContext(
-		ctx, http.MethodPost, webhookURL,
+		ctx,
+		http.MethodPost,
+		webhookURL.String(),
 		bytes.NewBuffer(body),
 	)
+	if err != nil {
+		return fmt.Errorf("creating webhook request: %w", err)
+	}
 
 	request.Header.Set("Content-Type", "application/json")
 
-	resp, err := svc.transport.RoundTrip(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL validated at Service construction time
 	if err != nil {
 		return fmt.Errorf("sending webhook request: %w", err)
 	}

internal/notify/notify_test.go

@@ -1,100 +0,0 @@
-package notify_test
-
-import (
-	"testing"
-
-	"sneak.berlin/go/dnswatcher/internal/notify"
-)
-
-func TestValidateWebhookURLValid(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name    string
-		input   string
-		wantURL string
-	}{
-		{
-			name:    "valid https URL",
-			input:   "https://hooks.slack.com/T00/B00",
-			wantURL: "https://hooks.slack.com/T00/B00",
-		},
-		{
-			name:    "valid http URL",
-			input:   "http://localhost:8080/webhook",
-			wantURL: "http://localhost:8080/webhook",
-		},
-		{
-			name:    "https with query",
-			input:   "https://ntfy.sh/topic?auth=tok",
-			wantURL: "https://ntfy.sh/topic?auth=tok",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := notify.ValidateWebhookURL(tt.input)
-			if err != nil {
-				t.Fatalf("unexpected error: %v", err)
-			}
-
-			if got.String() != tt.wantURL {
-				t.Errorf(
-					"got %q, want %q",
-					got.String(), tt.wantURL,
-				)
-			}
-		})
-	}
-}
-
-func TestValidateWebhookURLInvalid(t *testing.T) {
-	t.Parallel()
-
-	invalid := []struct {
-		name  string
-		input string
-	}{
-		{"ftp scheme", "ftp://example.com/file"},
-		{"file scheme", "file:///etc/passwd"},
-		{"empty string", ""},
-		{"no scheme", "example.com/webhook"},
-		{"no host", "https:///path"},
-	}
-
-	for _, tt := range invalid {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := notify.ValidateWebhookURL(tt.input)
-			if err == nil {
-				t.Errorf(
-					"expected error for %q, got %v",
-					tt.input, got,
-				)
-			}
-		})
-	}
-}
-
-func TestIsAllowedScheme(t *testing.T) {
-	t.Parallel()
-
-	if !notify.IsAllowedScheme("https") {
-		t.Error("https should be allowed")
-	}
-
-	if !notify.IsAllowedScheme("http") {
-		t.Error("http should be allowed")
-	}
-
-	if notify.IsAllowedScheme("ftp") {
-		t.Error("ftp should not be allowed")
-	}
-
-	if notify.IsAllowedScheme("") {
-		t.Error("empty scheme should not be allowed")
-	}
-}

internal/portcheck/portcheck.go

@@ -3,29 +3,18 @@ package portcheck
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"log/slog"
 	"net"
 	"strconv"
-	"sync"
 	"time"
 
 	"go.uber.org/fx"
-	"golang.org/x/sync/errgroup"
 
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 
-const (
+const defaultTimeout = 5 * time.Second
-	minPort        = 1
-	maxPort        = 65535
-	defaultTimeout = 5 * time.Second
-)
-
-// ErrInvalidPort is returned when a port number is outside
-// the valid TCP range (1–65535).
-var ErrInvalidPort = errors.New("invalid port number")
 
 // PortResult holds the outcome of a single TCP port check.
 type PortResult struct {
@@ -66,19 +55,6 @@ func NewStandalone() *Checker {
 	}
 }
 
-// validatePort checks that a port number is within the valid
-// TCP port range (1–65535).
-func validatePort(port int) error {
-	if port < minPort || port > maxPort {
-		return fmt.Errorf(
-			"%w: %d (must be between %d and %d)",
-			ErrInvalidPort, port, minPort, maxPort,
-		)
-	}
-
-	return nil
-}
-
 // CheckPort tests TCP connectivity to the given address and port.
 // It uses a 5-second timeout unless the context has an earlier
 // deadline.
@@ -87,18 +63,13 @@ func (c *Checker) CheckPort(
 	address string,
 	port int,
 ) (*PortResult, error) {
-	err := validatePort(port)
-	if err != nil {
-		return nil, err
-	}
-
 	target := net.JoinHostPort(
 		address, strconv.Itoa(port),
 	)
 
+	deadline, hasDeadline := ctx.Deadline()
 	timeout := defaultTimeout
 
-	deadline, hasDeadline := ctx.Deadline()
 	if hasDeadline {
 		remaining := time.Until(deadline)
 		if remaining < timeout {
@@ -106,62 +77,8 @@ func (c *Checker) CheckPort(
 		}
 	}
 
-	return c.checkConnection(ctx, target, timeout), nil
-}
-
-// CheckPorts tests TCP connectivity to multiple ports on the
-// given address concurrently. It returns a map of port number
-// to result.
-func (c *Checker) CheckPorts(
-	ctx context.Context,
-	address string,
-	ports []int,
-) (map[int]*PortResult, error) {
-	for _, port := range ports {
-		err := validatePort(port)
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	var mu sync.Mutex
-
-	results := make(map[int]*PortResult, len(ports))
-
-	g, ctx := errgroup.WithContext(ctx)
-
-	for _, port := range ports {
-		g.Go(func() error {
-			result, err := c.CheckPort(ctx, address, port)
-			if err != nil {
-				return fmt.Errorf(
-					"checking port %d: %w", port, err,
-				)
-			}
-
-			mu.Lock()
-			results[port] = result
-			mu.Unlock()
-
-			return nil
-		})
-	}
-
-	err := g.Wait()
-	if err != nil {
-		return nil, err
-	}
-
-	return results, nil
-}
-
-// checkConnection performs the TCP dial and returns a result.
-func (c *Checker) checkConnection(
-	ctx context.Context,
-	target string,
-	timeout time.Duration,
-) *PortResult {
 	dialer := &net.Dialer{Timeout: timeout}
+
 	start := time.Now()
 
 	conn, dialErr := dialer.DialContext(ctx, "tcp", target)
@@ -178,7 +95,7 @@ func (c *Checker) checkConnection(
 			Open:    false,
 			Error:   dialErr.Error(),
 			Latency: latency,
-		}
+		}, nil
 	}
 
 	closeErr := conn.Close()
@@ -199,5 +116,28 @@ func (c *Checker) checkConnection(
 	return &PortResult{
 		Open:    true,
 		Latency: latency,
+	}, nil
 }
+
+// CheckPorts tests TCP connectivity to multiple ports on the
+// given address. It returns a map of port number to result.
+func (c *Checker) CheckPorts(
+	ctx context.Context,
+	address string,
+	ports []int,
+) (map[int]*PortResult, error) {
+	results := make(map[int]*PortResult, len(ports))
+
+	for _, port := range ports {
+		result, err := c.CheckPort(ctx, address, port)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"checking port %d: %w", port, err,
+			)
+		}
+
+		results[port] = result
+	}
+
+	return results, nil
 }

internal/portcheck/portcheck_test.go

@@ -138,54 +138,6 @@ func TestCheckPortsMultiple(t *testing.T) {
 	}
 }
 
-func TestCheckPortInvalidPorts(t *testing.T) {
-	t.Parallel()
-
-	checker := portcheck.NewStandalone()
-
-	cases := []struct {
-		name string
-		port int
-	}{
-		{"zero", 0},
-		{"negative", -1},
-		{"too high", 65536},
-		{"very negative", -1000},
-		{"very high", 100000},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-
-			_, err := checker.CheckPort(
-				context.Background(), "127.0.0.1", tc.port,
-			)
-			if err == nil {
-				t.Errorf(
-					"expected error for port %d, got nil",
-					tc.port,
-				)
-			}
-		})
-	}
-}
-
-func TestCheckPortsInvalidPort(t *testing.T) {
-	t.Parallel()
-
-	checker := portcheck.NewStandalone()
-
-	_, err := checker.CheckPorts(
-		context.Background(),
-		"127.0.0.1",
-		[]int{80, 0, 443},
-	)
-	if err == nil {
-		t.Error("expected error for invalid port in list")
-	}
-}
-
 func TestCheckPortLatencyReasonable(t *testing.T) {
 	t.Parallel()
 

internal/resolver/dns_client.go

@@ -1,48 +0,0 @@
-package resolver
-
-import (
-	"context"
-	"time"
-
-	"github.com/miekg/dns"
-)
-
-// DNSClient abstracts DNS wire-protocol exchanges so the resolver
-// can be tested without hitting real nameservers.
-type DNSClient interface {
-	ExchangeContext(
-		ctx context.Context,
-		msg *dns.Msg,
-		addr string,
-	) (*dns.Msg, time.Duration, error)
-}
-
-// udpClient wraps a real dns.Client for production use.
-type udpClient struct {
-	timeout time.Duration
-}
-
-func (c *udpClient) ExchangeContext(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-) (*dns.Msg, time.Duration, error) {
-	cl := &dns.Client{Timeout: c.timeout}
-
-	return cl.ExchangeContext(ctx, msg, addr)
-}
-
-// tcpClient wraps a real dns.Client using TCP.
-type tcpClient struct {
-	timeout time.Duration
-}
-
-func (c *tcpClient) ExchangeContext(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-) (*dns.Msg, time.Duration, error) {
-	cl := &dns.Client{Net: "tcp", Timeout: c.timeout}
-
-	return cl.ExchangeContext(ctx, msg, addr)
-}

internal/resolver/errors.go

@@ -1,22 +0,0 @@
-package resolver
-
-import "errors"
-
-// Sentinel errors returned by the resolver.
-var (
-	// ErrNoNameservers is returned when no authoritative NS
-	// could be discovered for a domain.
-	ErrNoNameservers = errors.New(
-		"no authoritative nameservers found",
-	)
-
-	// ErrCNAMEDepthExceeded is returned when a CNAME chain
-	// exceeds MaxCNAMEDepth.
-	ErrCNAMEDepthExceeded = errors.New(
-		"CNAME chain depth exceeded",
-	)
-
-	// ErrContextCanceled wraps context cancellation for the
-	// resolver's iterative queries.
-	ErrContextCanceled = errors.New("context canceled")
-)

internal/resolver/iterative.go

@@ -1,778 +0,0 @@
-package resolver
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"math/rand"
-	"net"
-	"sort"
-	"strings"
-	"time"
-
-	"github.com/miekg/dns"
-)
-
-const (
-	queryTimeoutDuration = 2 * time.Second
-	maxRetries           = 2
-	maxDelegation        = 20
-	timeoutMultiplier    = 2
-	minDomainLabels      = 2
-)
-
-// ErrRefused is returned when a DNS server refuses a query.
-var ErrRefused = errors.New("dns query refused")
-
-func rootServerList() []string {
-	return []string{
-		"198.41.0.4",     // a.root-servers.net
-		"170.247.170.2",  // b
-		"192.33.4.12",    // c
-		"199.7.91.13",    // d
-		"192.203.230.10", // e
-		"192.5.5.241",    // f
-		"192.112.36.4",   // g
-		"198.97.190.53",  // h
-		"192.36.148.17",  // i
-		"192.58.128.30",  // j
-		"193.0.14.129",   // k
-		"199.7.83.42",    // l
-		"202.12.27.33",   // m
-	}
-}
-
-const maxRootServers = 3
-
-// randomRootServers returns a shuffled subset of root servers.
-func randomRootServers() []string {
-	all := rootServerList()
-	rand.Shuffle(len(all), func(i, j int) {
-		all[i], all[j] = all[j], all[i]
-	})
-
-	if len(all) > maxRootServers {
-		return all[:maxRootServers]
-	}
-
-	return all
-}
-
-func checkCtx(ctx context.Context) error {
-	err := ctx.Err()
-	if err != nil {
-		return ErrContextCanceled
-	}
-
-	return nil
-}
-
-func (r *Resolver) exchangeWithTimeout(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-	attempt int,
-) (*dns.Msg, error) {
-	_ = attempt // timeout escalation handled by client config
-
-	resp, _, err := r.client.ExchangeContext(ctx, msg, addr)
-
-	return resp, err
-}
-
-func (r *Resolver) tryExchange(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-) (*dns.Msg, error) {
-	var resp *dns.Msg
-
-	var err error
-
-	for attempt := range maxRetries {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		resp, err = r.exchangeWithTimeout(
-			ctx, msg, addr, attempt,
-		)
-		if err == nil {
-			break
-		}
-	}
-
-	return resp, err
-}
-
-func (r *Resolver) retryTCP(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-	resp *dns.Msg,
-) *dns.Msg {
-	if !resp.Truncated {
-		return resp
-	}
-
-	tcpResp, _, tcpErr := r.tcp.ExchangeContext(ctx, msg, addr)
-	if tcpErr == nil {
-		return tcpResp
-	}
-
-	return resp
-}
-
-// queryDNS sends a DNS query to a specific server IP.
-// Tries non-recursive first, falls back to recursive on
-// REFUSED (handles DNS interception environments).
-func (r *Resolver) queryDNS(
-	ctx context.Context,
-	serverIP string,
-	name string,
-	qtype uint16,
-) (*dns.Msg, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	name = dns.Fqdn(name)
-	addr := net.JoinHostPort(serverIP, "53")
-
-	msg := new(dns.Msg)
-	msg.SetQuestion(name, qtype)
-	msg.RecursionDesired = false
-
-	resp, err := r.tryExchange(ctx, msg, addr)
-	if err != nil {
-		return nil, fmt.Errorf("query %s @%s: %w", name, serverIP, err)
-	}
-
-	if resp.Rcode == dns.RcodeRefused {
-		msg.RecursionDesired = true
-
-		resp, err = r.tryExchange(ctx, msg, addr)
-		if err != nil {
-			return nil, fmt.Errorf(
-				"query %s @%s: %w", name, serverIP, err,
-			)
-		}
-
-		if resp.Rcode == dns.RcodeRefused {
-			return nil, fmt.Errorf(
-				"query %s @%s: %w", name, serverIP, ErrRefused,
-			)
-		}
-	}
-
-	resp = r.retryTCP(ctx, msg, addr, resp)
-
-	return resp, nil
-}
-
-func extractNSSet(rrs []dns.RR) []string {
-	nsSet := make(map[string]bool)
-
-	for _, rr := range rrs {
-		if ns, ok := rr.(*dns.NS); ok {
-			nsSet[strings.ToLower(ns.Ns)] = true
-		}
-	}
-
-	names := make([]string, 0, len(nsSet))
-	for n := range nsSet {
-		names = append(names, n)
-	}
-
-	sort.Strings(names)
-
-	return names
-}
-
-func extractGlue(rrs []dns.RR) map[string][]net.IP {
-	glue := make(map[string][]net.IP)
-
-	for _, rr := range rrs {
-		switch r := rr.(type) {
-		case *dns.A:
-			name := strings.ToLower(r.Hdr.Name)
-			glue[name] = append(glue[name], r.A)
-		case *dns.AAAA:
-			name := strings.ToLower(r.Hdr.Name)
-			glue[name] = append(glue[name], r.AAAA)
-		}
-	}
-
-	return glue
-}
-
-func glueIPs(nsNames []string, glue map[string][]net.IP) []string {
-	var ips []string
-
-	for _, ns := range nsNames {
-		for _, addr := range glue[ns] {
-			if v4 := addr.To4(); v4 != nil {
-				ips = append(ips, v4.String())
-			}
-		}
-	}
-
-	return ips
-}
-
-func (r *Resolver) followDelegation(
-	ctx context.Context,
-	domain string,
-	servers []string,
-) ([]string, error) {
-	for range maxDelegation {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		resp, err := r.queryServers(
-			ctx, servers, domain, dns.TypeNS,
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		ansNS := extractNSSet(resp.Answer)
-		if len(ansNS) > 0 {
-			return ansNS, nil
-		}
-
-		authNS := extractNSSet(resp.Ns)
-		if len(authNS) == 0 {
-			return r.resolveNSRecursive(ctx, domain)
-		}
-
-		glue := extractGlue(resp.Extra)
-		nextServers := glueIPs(authNS, glue)
-
-		if len(nextServers) == 0 {
-			nextServers = r.resolveNSIPs(ctx, authNS)
-		}
-
-		if len(nextServers) == 0 {
-			return nil, ErrNoNameservers
-		}
-
-		servers = nextServers
-	}
-
-	return nil, ErrNoNameservers
-}
-
-func (r *Resolver) queryServers(
-	ctx context.Context,
-	servers []string,
-	name string,
-	qtype uint16,
-) (*dns.Msg, error) {
-	var lastErr error
-
-	for _, ip := range servers {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		resp, err := r.queryDNS(ctx, ip, name, qtype)
-		if err == nil {
-			return resp, nil
-		}
-
-		lastErr = err
-	}
-
-	return nil, fmt.Errorf("all servers failed: %w", lastErr)
-}
-
-func (r *Resolver) resolveNSIPs(
-	ctx context.Context,
-	nsNames []string,
-) []string {
-	var ips []string
-
-	for _, ns := range nsNames {
-		resolved, err := r.resolveARecord(ctx, ns)
-		if err == nil {
-			ips = append(ips, resolved...)
-		}
-
-		if len(ips) > 0 {
-			break
-		}
-	}
-
-	return ips
-}
-
-// resolveNSRecursive queries for NS records using recursive
-// resolution as a fallback for intercepted environments.
-func (r *Resolver) resolveNSRecursive(
-	ctx context.Context,
-	domain string,
-) ([]string, error) {
-	domain = dns.Fqdn(domain)
-	msg := new(dns.Msg)
-	msg.SetQuestion(domain, dns.TypeNS)
-	msg.RecursionDesired = true
-
-	for _, ip := range randomRootServers() {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		addr := net.JoinHostPort(ip, "53")
-
-		resp, _, err := r.client.ExchangeContext(ctx, msg, addr)
-		if err != nil {
-			continue
-		}
-
-		nsNames := extractNSSet(resp.Answer)
-		if len(nsNames) > 0 {
-			return nsNames, nil
-		}
-	}
-
-	return nil, ErrNoNameservers
-}
-
-// resolveARecord resolves a hostname to IPv4 addresses.
-func (r *Resolver) resolveARecord(
-	ctx context.Context,
-	hostname string,
-) ([]string, error) {
-	hostname = dns.Fqdn(hostname)
-	msg := new(dns.Msg)
-	msg.SetQuestion(hostname, dns.TypeA)
-	msg.RecursionDesired = true
-
-	for _, ip := range randomRootServers() {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		addr := net.JoinHostPort(ip, "53")
-
-		resp, _, err := r.client.ExchangeContext(ctx, msg, addr)
-		if err != nil {
-			continue
-		}
-
-		var ips []string
-
-		for _, rr := range resp.Answer {
-			if a, ok := rr.(*dns.A); ok {
-				ips = append(ips, a.A.String())
-			}
-		}
-
-		if len(ips) > 0 {
-			return ips, nil
-		}
-	}
-
-	return nil, fmt.Errorf(
-		"cannot resolve %s: %w", hostname, ErrNoNameservers,
-	)
-}
-
-// FindAuthoritativeNameservers traces the delegation chain from
-// root servers to discover all authoritative nameservers for the
-// given domain. Walks up the label hierarchy for subdomains.
-func (r *Resolver) FindAuthoritativeNameservers(
-	ctx context.Context,
-	domain string,
-) ([]string, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	domain = dns.Fqdn(strings.ToLower(domain))
-	labels := dns.SplitDomainName(domain)
-
-	for i := range labels {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		candidate := strings.Join(labels[i:], ".") + "."
-
-		nsNames, err := r.followDelegation(
-			ctx, candidate, randomRootServers(),
-		)
-		if err == nil && len(nsNames) > 0 {
-			sort.Strings(nsNames)
-
-			return nsNames, nil
-		}
-	}
-
-	return nil, ErrNoNameservers
-}
-
-// QueryNameserver queries a specific nameserver for all record
-// types and builds a NameserverResponse.
-func (r *Resolver) QueryNameserver(
-	ctx context.Context,
-	nsHostname string,
-	hostname string,
-) (*NameserverResponse, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	nsIPs, err := r.resolveARecord(ctx, nsHostname)
-	if err != nil {
-		return nil, fmt.Errorf("resolving NS %s: %w", nsHostname, err)
-	}
-
-	hostname = dns.Fqdn(hostname)
-
-	return r.queryAllTypes(ctx, nsHostname, nsIPs[0], hostname)
-}
-
-// QueryNameserverIP queries a nameserver by its IP address directly,
-// bypassing NS hostname resolution.
-func (r *Resolver) QueryNameserverIP(
-	ctx context.Context,
-	nsHostname string,
-	nsIP string,
-	hostname string,
-) (*NameserverResponse, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	hostname = dns.Fqdn(hostname)
-
-	return r.queryAllTypes(ctx, nsHostname, nsIP, hostname)
-}
-
-func (r *Resolver) queryAllTypes(
-	ctx context.Context,
-	nsHostname string,
-	nsIP string,
-	hostname string,
-) (*NameserverResponse, error) {
-	resp := &NameserverResponse{
-		Nameserver: nsHostname,
-		Records:    make(map[string][]string),
-		Status:     StatusOK,
-	}
-
-	qtypes := []uint16{
-		dns.TypeA, dns.TypeAAAA, dns.TypeCNAME,
-		dns.TypeMX, dns.TypeTXT, dns.TypeSRV,
-		dns.TypeCAA, dns.TypeNS,
-	}
-
-	state := r.queryEachType(ctx, nsIP, hostname, qtypes, resp)
-	classifyResponse(resp, state)
-
-	return resp, nil
-}
-
-type queryState struct {
-	gotNXDomain bool
-	gotSERVFAIL bool
-	gotTimeout  bool
-	hasRecords  bool
-}
-
-func (r *Resolver) queryEachType(
-	ctx context.Context,
-	nsIP string,
-	hostname string,
-	qtypes []uint16,
-	resp *NameserverResponse,
-) queryState {
-	var state queryState
-
-	for _, qtype := range qtypes {
-		if checkCtx(ctx) != nil {
-			break
-		}
-
-		r.querySingleType(ctx, nsIP, hostname, qtype, resp, &state)
-	}
-
-	for k := range resp.Records {
-		sort.Strings(resp.Records[k])
-	}
-
-	return state
-}
-
-func (r *Resolver) querySingleType(
-	ctx context.Context,
-	nsIP string,
-	hostname string,
-	qtype uint16,
-	resp *NameserverResponse,
-	state *queryState,
-) {
-	msg, err := r.queryDNS(ctx, nsIP, hostname, qtype)
-	if err != nil {
-		if isTimeout(err) {
-			state.gotTimeout = true
-		}
-
-		return
-	}
-
-	if msg.Rcode == dns.RcodeNameError {
-		state.gotNXDomain = true
-
-		return
-	}
-
-	if msg.Rcode == dns.RcodeServerFailure {
-		state.gotSERVFAIL = true
-
-		return
-	}
-
-	collectAnswerRecords(msg, resp, state)
-}
-
-func collectAnswerRecords(
-	msg *dns.Msg,
-	resp *NameserverResponse,
-	state *queryState,
-) {
-	for _, rr := range msg.Answer {
-		val := extractRecordValue(rr)
-		if val == "" {
-			continue
-		}
-
-		typeName := dns.TypeToString[rr.Header().Rrtype]
-		resp.Records[typeName] = append(
-			resp.Records[typeName], val,
-		)
-		state.hasRecords = true
-	}
-}
-
-// isTimeout checks whether an error is a network timeout.
-func isTimeout(err error) bool {
-	var netErr net.Error
-	if errors.As(err, &netErr) {
-		return netErr.Timeout()
-	}
-
-	return false
-}
-
-func classifyResponse(resp *NameserverResponse, state queryState) {
-	switch {
-	case state.gotNXDomain && !state.hasRecords:
-		resp.Status = StatusNXDomain
-	case state.gotTimeout && !state.hasRecords:
-		resp.Status = StatusTimeout
-		resp.Error = "all queries timed out"
-	case state.gotSERVFAIL && !state.hasRecords:
-		resp.Status = StatusError
-		resp.Error = "server returned SERVFAIL"
-	case !state.hasRecords && !state.gotNXDomain:
-		resp.Status = StatusNoData
-	}
-}
-
-// extractRecordValue formats a DNS RR value as a string.
-func extractRecordValue(rr dns.RR) string {
-	switch r := rr.(type) {
-	case *dns.A:
-		return r.A.String()
-	case *dns.AAAA:
-		return r.AAAA.String()
-	case *dns.CNAME:
-		return r.Target
-	case *dns.MX:
-		return fmt.Sprintf("%d %s", r.Preference, r.Mx)
-	case *dns.TXT:
-		return strings.Join(r.Txt, "")
-	case *dns.SRV:
-		return fmt.Sprintf(
-			"%d %d %d %s",
-			r.Priority, r.Weight, r.Port, r.Target,
-		)
-	case *dns.CAA:
-		return fmt.Sprintf(
-			"%d %s \"%s\"", r.Flag, r.Tag, r.Value,
-		)
-	case *dns.NS:
-		return r.Ns
-	default:
-		return ""
-	}
-}
-
-// parentDomain returns the registerable parent domain.
-func parentDomain(hostname string) string {
-	hostname = dns.Fqdn(strings.ToLower(hostname))
-	labels := dns.SplitDomainName(hostname)
-
-	if len(labels) <= minDomainLabels {
-		return strings.Join(labels, ".") + "."
-	}
-
-	return strings.Join(
-		labels[len(labels)-minDomainLabels:], ".",
-	) + "."
-}
-
-// QueryAllNameservers discovers auth NSes for the hostname's
-// parent domain, then queries each one independently.
-func (r *Resolver) QueryAllNameservers(
-	ctx context.Context,
-	hostname string,
-) (map[string]*NameserverResponse, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	parent := parentDomain(hostname)
-
-	nameservers, err := r.FindAuthoritativeNameservers(ctx, parent)
-	if err != nil {
-		return nil, err
-	}
-
-	return r.queryEachNS(ctx, nameservers, hostname)
-}
-
-func (r *Resolver) queryEachNS(
-	ctx context.Context,
-	nameservers []string,
-	hostname string,
-) (map[string]*NameserverResponse, error) {
-	results := make(map[string]*NameserverResponse)
-
-	for _, ns := range nameservers {
-		if checkCtx(ctx) != nil {
-			return nil, ErrContextCanceled
-		}
-
-		resp, err := r.QueryNameserver(ctx, ns, hostname)
-		if err != nil {
-			results[ns] = &NameserverResponse{
-				Nameserver: ns,
-				Records:    make(map[string][]string),
-				Status:     StatusError,
-				Error:      err.Error(),
-			}
-
-			continue
-		}
-
-		results[ns] = resp
-	}
-
-	return results, nil
-}
-
-// LookupNS returns the NS record set for a domain.
-func (r *Resolver) LookupNS(
-	ctx context.Context,
-	domain string,
-) ([]string, error) {
-	return r.FindAuthoritativeNameservers(ctx, domain)
-}
-
-// LookupAllRecords performs iterative resolution to find all DNS
-// records for the given hostname, keyed by authoritative nameserver.
-func (r *Resolver) LookupAllRecords(
-	ctx context.Context,
-	hostname string,
-) (map[string]map[string][]string, error) {
-	results, err := r.QueryAllNameservers(ctx, hostname)
-	if err != nil {
-		return nil, err
-	}
-
-	out := make(map[string]map[string][]string, len(results))
-	for ns, resp := range results {
-		out[ns] = resp.Records
-	}
-
-	return out, nil
-}
-
-// ResolveIPAddresses resolves a hostname to all IPv4 and IPv6
-// addresses, following CNAME chains up to MaxCNAMEDepth.
-func (r *Resolver) ResolveIPAddresses(
-	ctx context.Context,
-	hostname string,
-) ([]string, error) {
-	if checkCtx(ctx) != nil {
-		return nil, ErrContextCanceled
-	}
-
-	return r.resolveIPWithCNAME(ctx, hostname, 0)
-}
-
-func (r *Resolver) resolveIPWithCNAME(
-	ctx context.Context,
-	hostname string,
-	depth int,
-) ([]string, error) {
-	if depth > MaxCNAMEDepth {
-		return nil, ErrCNAMEDepthExceeded
-	}
-
-	results, err := r.QueryAllNameservers(ctx, hostname)
-	if err != nil {
-		return nil, err
-	}
-
-	ips, cnameTarget := collectIPs(results)
-
-	if len(ips) == 0 && cnameTarget != "" {
-		return r.resolveIPWithCNAME(ctx, cnameTarget, depth+1)
-	}
-
-	sort.Strings(ips)
-
-	return ips, nil
-}
-
-func collectIPs(
-	results map[string]*NameserverResponse,
-) ([]string, string) {
-	seen := make(map[string]bool)
-
-	var ips []string
-
-	var cnameTarget string
-
-	for _, resp := range results {
-		if resp.Status == StatusNXDomain {
-			continue
-		}
-
-		for _, ip := range resp.Records["A"] {
-			if !seen[ip] {
-				seen[ip] = true
-				ips = append(ips, ip)
-			}
-		}
-
-		for _, ip := range resp.Records["AAAA"] {
-			if !seen[ip] {
-				seen[ip] = true
-				ips = append(ips, ip)
-			}
-		}
-
-		if len(resp.Records["CNAME"]) > 0 && cnameTarget == "" {
-			cnameTarget = resp.Records["CNAME"][0]
-		}
-	}
-
-	return ips, cnameTarget
-}

internal/resolver/resolver.go

@@ -1,9 +1,9 @@
 // Package resolver provides iterative DNS resolution from root nameservers.
-// It traces the full delegation chain from IANA root servers through TLD
-// and domain nameservers, never relying on upstream recursive resolvers.
 package resolver
 
 import (
+	"context"
+	"errors"
 	"log/slog"
 
 	"go.uber.org/fx"
@@ -11,17 +11,8 @@ import (
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 
-// Query status constants matching the state model.
+// ErrNotImplemented indicates the resolver is not yet implemented.
-const (
+var ErrNotImplemented = errors.New("resolver not yet implemented")
-	StatusOK       = "ok"
-	StatusError    = "error"
-	StatusNXDomain = "nxdomain"
-	StatusNoData   = "nodata"
-	StatusTimeout  = "timeout"
-)
-
-// MaxCNAMEDepth is the maximum CNAME chain depth to follow.
-const MaxCNAMEDepth = 10
 
 // Params contains dependencies for Resolver.
 type Params struct {
@@ -30,54 +21,44 @@ type Params struct {
 	Logger *logger.Logger
 }
 
-// NameserverResponse holds one nameserver's response for a query.
-type NameserverResponse struct {
-	Nameserver string
-	Records    map[string][]string
-	Status     string
-	Error      string
-}
-
 // Resolver performs iterative DNS resolution from root servers.
 type Resolver struct {
 	log *slog.Logger
-	client DNSClient
-	tcp    DNSClient
 }
 
-// New creates a new Resolver instance for use with uber/fx.
+// New creates a new Resolver instance.
 func New(
 	_ fx.Lifecycle,
 	params Params,
 ) (*Resolver, error) {
 	return &Resolver{
 		log: params.Logger.Get(),
-		client: &udpClient{timeout: queryTimeoutDuration},
-		tcp:    &tcpClient{timeout: queryTimeoutDuration},
 	}, nil
 }
 
-// NewFromLogger creates a Resolver directly from an slog.Logger,
+// LookupNS performs iterative resolution to find authoritative
-// useful for testing without the fx lifecycle.
+// nameservers for the given domain.
-func NewFromLogger(log *slog.Logger) *Resolver {
+func (r *Resolver) LookupNS(
-	return &Resolver{
+	_ context.Context,
-		log:    log,
+	_ string,
-		client: &udpClient{timeout: queryTimeoutDuration},
+) ([]string, error) {
-		tcp:    &tcpClient{timeout: queryTimeoutDuration},
+	return nil, ErrNotImplemented
-	}
 }
 
-// NewFromLoggerWithClient creates a Resolver with a custom DNS
+// LookupAllRecords performs iterative resolution to find all DNS
-// client, useful for testing with mock DNS responses.
+// records for the given hostname, keyed by authoritative nameserver.
-func NewFromLoggerWithClient(
+func (r *Resolver) LookupAllRecords(
-	log *slog.Logger,
+	_ context.Context,
-	client DNSClient,
+	_ string,
-) *Resolver {
+) (map[string]map[string][]string, error) {
-	return &Resolver{
+	return nil, ErrNotImplemented
-		log:    log,
-		client: client,
-		tcp:    client,
-	}
 }
 
-// Method implementations are in iterative.go.
+// ResolveIPAddresses resolves a hostname to all IPv4 and IPv6
+// addresses, following CNAME chains.
+func (r *Resolver) ResolveIPAddresses(
+	_ context.Context,
+	_ string,
+) ([]string, error) {
+	return nil, ErrNotImplemented
+}

internal/resolver/resolver_test.go

@@ -1,688 +0,0 @@
-package resolver_test
-
-import (
-	"context"
-	"log/slog"
-	"net"
-	"os"
-	"sort"
-	"strings"
-	"testing"
-	"time"
-
-	"github.com/miekg/dns"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"sneak.berlin/go/dnswatcher/internal/resolver"
-)
-
-// ----------------------------------------------------------------
-// Test helpers
-// ----------------------------------------------------------------
-
-func newTestResolver(t *testing.T) *resolver.Resolver {
-	t.Helper()
-
-	log := slog.New(slog.NewTextHandler(
-		os.Stderr,
-		&slog.HandlerOptions{Level: slog.LevelDebug},
-	))
-
-	return resolver.NewFromLogger(log)
-}
-
-func testContext(t *testing.T) context.Context {
-	t.Helper()
-
-	ctx, cancel := context.WithTimeout(
-		context.Background(), 60*time.Second,
-	)
-	t.Cleanup(cancel)
-
-	return ctx
-}
-
-func findOneNSForDomain(
-	t *testing.T,
-	r *resolver.Resolver,
-	ctx context.Context, //nolint:revive // test helper
-	domain string,
-) string {
-	t.Helper()
-
-	nameservers, err := r.FindAuthoritativeNameservers(
-		ctx, domain,
-	)
-	require.NoError(t, err)
-	require.NotEmpty(t, nameservers)
-
-	return nameservers[0]
-}
-
-// ----------------------------------------------------------------
-// FindAuthoritativeNameservers tests
-// ----------------------------------------------------------------
-
-func TestFindAuthoritativeNameservers_ValidDomain(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-	require.NotEmpty(t, nameservers)
-
-	hasGoogleNS := false
-
-	for _, ns := range nameservers {
-		if strings.Contains(ns, "google") {
-			hasGoogleNS = true
-
-			break
-		}
-	}
-
-	assert.True(t, hasGoogleNS,
-		"expected google nameservers, got: %v", nameservers,
-	)
-}
-
-func TestFindAuthoritativeNameservers_Subdomain(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.FindAuthoritativeNameservers(
-		ctx, "www.google.com",
-	)
-	require.NoError(t, err)
-	require.NotEmpty(t, nameservers)
-}
-
-func TestFindAuthoritativeNameservers_ReturnsSorted(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	assert.True(
-		t,
-		sort.StringsAreSorted(nameservers),
-		"nameservers should be sorted, got: %v", nameservers,
-	)
-}
-
-func TestFindAuthoritativeNameservers_Deterministic(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	first, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	second, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, first, second)
-}
-
-func TestFindAuthoritativeNameservers_TrailingDot(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ns1, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	ns2, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com.",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, ns1, ns2)
-}
-
-func TestFindAuthoritativeNameservers_CloudflareDomain(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.FindAuthoritativeNameservers(
-		ctx, "cloudflare.com",
-	)
-	require.NoError(t, err)
-	require.NotEmpty(t, nameservers)
-
-	for _, ns := range nameservers {
-		assert.True(t, strings.HasSuffix(ns, "."),
-			"NS should be FQDN with trailing dot: %s", ns,
-		)
-	}
-}
-
-// ----------------------------------------------------------------
-// QueryNameserver tests
-// ----------------------------------------------------------------
-
-func TestQueryNameserver_BasicA(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "www.google.com",
-	)
-	require.NoError(t, err)
-	require.NotNil(t, resp)
-
-	assert.Equal(t, resolver.StatusOK, resp.Status)
-	assert.Equal(t, ns, resp.Nameserver)
-
-	hasRecords := len(resp.Records["A"]) > 0 ||
-		len(resp.Records["CNAME"]) > 0
-	assert.True(t, hasRecords,
-		"expected A or CNAME records for www.google.com",
-	)
-}
-
-func TestQueryNameserver_AAAA(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "cloudflare.com",
-	)
-	require.NoError(t, err)
-
-	aaaaRecords := resp.Records["AAAA"]
-	require.NotEmpty(t, aaaaRecords,
-		"cloudflare.com should have AAAA records",
-	)
-
-	for _, ip := range aaaaRecords {
-		parsed := net.ParseIP(ip)
-		require.NotNil(t, parsed,
-			"should be valid IP: %s", ip,
-		)
-	}
-}
-
-func TestQueryNameserver_MX(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "google.com",
-	)
-	require.NoError(t, err)
-
-	mxRecords := resp.Records["MX"]
-	require.NotEmpty(t, mxRecords,
-		"google.com should have MX records",
-	)
-}
-
-func TestQueryNameserver_TXT(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "google.com",
-	)
-	require.NoError(t, err)
-
-	txtRecords := resp.Records["TXT"]
-	require.NotEmpty(t, txtRecords,
-		"google.com should have TXT records",
-	)
-
-	hasSPF := false
-
-	for _, txt := range txtRecords {
-		if strings.Contains(txt, "v=spf1") {
-			hasSPF = true
-
-			break
-		}
-	}
-
-	assert.True(t, hasSPF,
-		"google.com should have SPF TXT record",
-	)
-}
-
-func TestQueryNameserver_NXDomain(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns,
-		"this-surely-does-not-exist-xyz.google.com",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, resolver.StatusNXDomain, resp.Status)
-}
-
-func TestQueryNameserver_RecordsSorted(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "google.com",
-	)
-	require.NoError(t, err)
-
-	for recordType, values := range resp.Records {
-		assert.True(
-			t,
-			sort.StringsAreSorted(values),
-			"%s records should be sorted", recordType,
-		)
-	}
-}
-
-func TestQueryNameserver_ResponseIncludesNameserver(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns, "cloudflare.com",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, ns, resp.Nameserver)
-}
-
-func TestQueryNameserver_EmptyRecordsOnNXDomain(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp, err := r.QueryNameserver(
-		ctx, ns,
-		"this-surely-does-not-exist-xyz.google.com",
-	)
-	require.NoError(t, err)
-
-	totalRecords := 0
-	for _, values := range resp.Records {
-		totalRecords += len(values)
-	}
-
-	assert.Zero(t, totalRecords)
-}
-
-func TestQueryNameserver_TrailingDotHandling(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-	ns := findOneNSForDomain(t, r, ctx, "google.com")
-
-	resp1, err := r.QueryNameserver(
-		ctx, ns, "google.com",
-	)
-	require.NoError(t, err)
-
-	resp2, err := r.QueryNameserver(
-		ctx, ns, "google.com.",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, resp1.Status, resp2.Status)
-}
-
-// ----------------------------------------------------------------
-// QueryAllNameservers tests
-// ----------------------------------------------------------------
-
-func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	results, err := r.QueryAllNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-	require.NotEmpty(t, results)
-
-	assert.GreaterOrEqual(t, len(results), 2)
-
-	for ns, resp := range results {
-		assert.Equal(t, ns, resp.Nameserver)
-	}
-}
-
-func TestQueryAllNameservers_AllReturnOK(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	results, err := r.QueryAllNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	for ns, resp := range results {
-		assert.Equal(
-			t, resolver.StatusOK, resp.Status,
-			"NS %s should return OK", ns,
-		)
-	}
-}
-
-func TestQueryAllNameservers_NXDomainFromAllNS(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	results, err := r.QueryAllNameservers(
-		ctx,
-		"this-surely-does-not-exist-xyz.google.com",
-	)
-	require.NoError(t, err)
-
-	for ns, resp := range results {
-		assert.Equal(
-			t, resolver.StatusNXDomain, resp.Status,
-			"NS %s should return nxdomain", ns,
-		)
-	}
-}
-
-// ----------------------------------------------------------------
-// LookupNS tests
-// ----------------------------------------------------------------
-
-func TestLookupNS_ValidDomain(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.LookupNS(ctx, "google.com")
-	require.NoError(t, err)
-	require.NotEmpty(t, nameservers)
-
-	for _, ns := range nameservers {
-		assert.True(t, strings.HasSuffix(ns, "."),
-			"NS should have trailing dot: %s", ns,
-		)
-	}
-}
-
-func TestLookupNS_Sorted(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	nameservers, err := r.LookupNS(ctx, "google.com")
-	require.NoError(t, err)
-
-	assert.True(t, sort.StringsAreSorted(nameservers))
-}
-
-func TestLookupNS_MatchesFindAuthoritative(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	fromLookup, err := r.LookupNS(ctx, "google.com")
-	require.NoError(t, err)
-
-	fromFind, err := r.FindAuthoritativeNameservers(
-		ctx, "google.com",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, fromFind, fromLookup)
-}
-
-// ----------------------------------------------------------------
-// ResolveIPAddresses tests
-// ----------------------------------------------------------------
-
-func TestResolveIPAddresses_ReturnsIPs(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ips, err := r.ResolveIPAddresses(ctx, "google.com")
-	require.NoError(t, err)
-	require.NotEmpty(t, ips)
-
-	for _, ip := range ips {
-		parsed := net.ParseIP(ip)
-		assert.NotNil(t, parsed,
-			"should be valid IP: %s", ip,
-		)
-	}
-}
-
-func TestResolveIPAddresses_Deduplicated(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ips, err := r.ResolveIPAddresses(ctx, "google.com")
-	require.NoError(t, err)
-
-	seen := make(map[string]bool)
-
-	for _, ip := range ips {
-		assert.False(t, seen[ip], "duplicate IP: %s", ip)
-		seen[ip] = true
-	}
-}
-
-func TestResolveIPAddresses_Sorted(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ips, err := r.ResolveIPAddresses(ctx, "google.com")
-	require.NoError(t, err)
-
-	assert.True(t, sort.StringsAreSorted(ips))
-}
-
-func TestResolveIPAddresses_NXDomainReturnsEmpty(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ips, err := r.ResolveIPAddresses(
-		ctx,
-		"this-surely-does-not-exist-xyz.google.com",
-	)
-	require.NoError(t, err)
-	assert.Empty(t, ips)
-}
-
-func TestResolveIPAddresses_CloudflareDomain(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx := testContext(t)
-
-	ips, err := r.ResolveIPAddresses(ctx, "cloudflare.com")
-	require.NoError(t, err)
-	require.NotEmpty(t, ips)
-}
-
-// ----------------------------------------------------------------
-// Context cancellation tests
-// ----------------------------------------------------------------
-
-func TestFindAuthoritativeNameservers_ContextCanceled(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-
-	_, err := r.FindAuthoritativeNameservers(ctx, "google.com")
-	assert.Error(t, err)
-}
-
-func TestQueryNameserver_ContextCanceled(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-
-	_, err := r.QueryNameserver(
-		ctx, "ns1.google.com.", "google.com",
-	)
-	assert.Error(t, err)
-}
-
-func TestQueryAllNameservers_ContextCanceled(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-
-	_, err := r.QueryAllNameservers(ctx, "google.com")
-	assert.Error(t, err)
-}
-
-// ----------------------------------------------------------------
-// Timeout tests
-// ----------------------------------------------------------------
-
-func TestQueryNameserverIP_Timeout(t *testing.T) {
-	t.Parallel()
-
-	log := slog.New(slog.NewTextHandler(
-		os.Stderr,
-		&slog.HandlerOptions{Level: slog.LevelDebug},
-	))
-
-	r := resolver.NewFromLoggerWithClient(
-		log, &timeoutClient{},
-	)
-
-	ctx, cancel := context.WithTimeout(
-		context.Background(), 10*time.Second,
-	)
-	t.Cleanup(cancel)
-
-	// Query any IP — the client always returns a timeout error.
-	resp, err := r.QueryNameserverIP(
-		ctx, "unreachable.test.", "192.0.2.1",
-		"example.com",
-	)
-	require.NoError(t, err)
-
-	assert.Equal(t, resolver.StatusTimeout, resp.Status)
-	assert.NotEmpty(t, resp.Error)
-}
-
-// timeoutClient simulates DNS timeout errors for testing.
-type timeoutClient struct{}
-
-func (c *timeoutClient) ExchangeContext(
-	_ context.Context,
-	_ *dns.Msg,
-	_ string,
-) (*dns.Msg, time.Duration, error) {
-	return nil, 0, &net.OpError{
-		Op:  "read",
-		Net: "udp",
-		Err: &timeoutError{},
-	}
-}
-
-type timeoutError struct{}
-
-func (e *timeoutError) Error() string   { return "i/o timeout" }
-func (e *timeoutError) Timeout() bool   { return true }
-func (e *timeoutError) Temporary() bool { return true }
-
-func TestResolveIPAddresses_ContextCanceled(t *testing.T) {
-	t.Parallel()
-
-	r := newTestResolver(t)
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-
-	_, err := r.ResolveIPAddresses(ctx, "google.com")
-	assert.Error(t, err)
-}

internal/state/state.go

@@ -156,8 +156,8 @@ func (s *State) Load() error {
 
 // Save writes the current state to disk atomically.
 func (s *State) Save() error {
-	s.mu.Lock()
+	s.mu.RLock()
-	defer s.mu.Unlock()
+	defer s.mu.RUnlock()
 
 	s.snapshot.LastUpdated = time.Now().UTC()
 

internal/tlscheck/extractcertinfo_test.go

@@ -1,67 +0,0 @@
-package tlscheck_test
-
-import (
-	"context"
-	"crypto/tls"
-	"errors"
-	"net"
-	"testing"
-	"time"
-
-	"sneak.berlin/go/dnswatcher/internal/tlscheck"
-)
-
-func TestCheckCertificateNoPeerCerts(t *testing.T) {
-	t.Parallel()
-
-	lc := &net.ListenConfig{}
-
-	ln, err := lc.Listen(
-		context.Background(), "tcp", "127.0.0.1:0",
-	)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	defer func() { _ = ln.Close() }()
-
-	addr, ok := ln.Addr().(*net.TCPAddr)
-	if !ok {
-		t.Fatal("unexpected address type")
-	}
-
-	// Accept and immediately close to cause TLS handshake failure.
-	go func() {
-		conn, err := ln.Accept()
-		if err != nil {
-			return
-		}
-
-		_ = conn.Close()
-	}()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(2*time.Second),
-		tlscheck.WithTLSConfig(&tls.Config{
-			InsecureSkipVerify: true, //nolint:gosec // test
-			MinVersion:         tls.VersionTLS12,
-		}),
-		tlscheck.WithPort(addr.Port),
-	)
-
-	_, err = checker.CheckCertificate(
-		context.Background(), "127.0.0.1", "localhost",
-	)
-	if err == nil {
-		t.Fatal("expected error when server presents no certs")
-	}
-}
-
-func TestErrNoPeerCertificatesIsSentinel(t *testing.T) {
-	t.Parallel()
-
-	err := tlscheck.ErrNoPeerCertificates
-	if !errors.Is(err, tlscheck.ErrNoPeerCertificates) {
-		t.Fatal("expected sentinel error to match")
-	}
-}

internal/tlscheck/tlscheck.go

@@ -3,12 +3,8 @@ package tlscheck
 
 import (
 	"context"
-	"crypto/tls"
 	"errors"
-	"fmt"
 	"log/slog"
-	"net"
-	"strconv"
 	"time"
 
 	"go.uber.org/fx"
@@ -16,56 +12,11 @@ import (
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 
-const (
+// ErrNotImplemented indicates the TLS checker is not yet implemented.
-	defaultTimeout = 10 * time.Second
+var ErrNotImplemented = errors.New(
-	defaultPort    = 443
+	"tls checker not yet implemented",
 )
 
-// ErrUnexpectedConnType indicates the connection was not a TLS
-// connection.
-var ErrUnexpectedConnType = errors.New(
-	"unexpected connection type",
-)
-
-// ErrNoPeerCertificates indicates the TLS connection had no peer
-// certificates.
-var ErrNoPeerCertificates = errors.New(
-	"no peer certificates",
-)
-
-// CertificateInfo holds information about a TLS certificate.
-type CertificateInfo struct {
-	CommonName              string
-	Issuer                  string
-	NotAfter                time.Time
-	SubjectAlternativeNames []string
-	SerialNumber            string
-}
-
-// Option configures a Checker.
-type Option func(*Checker)
-
-// WithTimeout sets the connection timeout.
-func WithTimeout(d time.Duration) Option {
-	return func(c *Checker) {
-		c.timeout = d
-	}
-}
-
-// WithTLSConfig sets a custom TLS configuration.
-func WithTLSConfig(cfg *tls.Config) Option {
-	return func(c *Checker) {
-		c.tlsConfig = cfg
-	}
-}
-
-// WithPort sets the TLS port to connect to.
-func WithPort(port int) Option {
-	return func(c *Checker) {
-		c.port = port
-	}
-}
-
 // Params contains dependencies for Checker.
 type Params struct {
 	fx.In
@@ -76,9 +27,14 @@ type Params struct {
 // Checker performs TLS certificate inspection.
 type Checker struct {
 	log *slog.Logger
-	timeout   time.Duration
+}
-	tlsConfig *tls.Config
+
-	port      int
+// CertificateInfo holds information about a TLS certificate.
+type CertificateInfo struct {
+	CommonName              string
+	Issuer                  string
+	NotAfter                time.Time
+	SubjectAlternativeNames []string
 }
 
 // New creates a new TLS Checker instance.
@@ -88,109 +44,15 @@ func New(
 ) (*Checker, error) {
 	return &Checker{
 		log: params.Logger.Get(),
-		timeout: defaultTimeout,
-		port:    defaultPort,
 	}, nil
 }
 
-// NewStandalone creates a Checker without fx dependencies.
+// CheckCertificate connects to the given IP:port using SNI and
-func NewStandalone(opts ...Option) *Checker {
+// returns certificate information.
-	checker := &Checker{
-		log:     slog.Default(),
-		timeout: defaultTimeout,
-		port:    defaultPort,
-	}
-
-	for _, opt := range opts {
-		opt(checker)
-	}
-
-	return checker
-}
-
-// CheckCertificate connects to the given IP address using the
-// specified SNI hostname and returns certificate information.
 func (c *Checker) CheckCertificate(
-	ctx context.Context,
+	_ context.Context,
-	ipAddress string,
+	_ string,
-	sniHostname string,
+	_ string,
 ) (*CertificateInfo, error) {
-	target := net.JoinHostPort(
+	return nil, ErrNotImplemented
-		ipAddress, strconv.Itoa(c.port),
-	)
-
-	tlsCfg := c.buildTLSConfig(sniHostname)
-	dialer := &tls.Dialer{
-		NetDialer: &net.Dialer{Timeout: c.timeout},
-		Config:    tlsCfg,
-	}
-
-	conn, err := dialer.DialContext(ctx, "tcp", target)
-	if err != nil {
-		return nil, fmt.Errorf(
-			"TLS dial to %s: %w", target, err,
-		)
-	}
-
-	defer func() {
-		closeErr := conn.Close()
-		if closeErr != nil {
-			c.log.Debug(
-				"closing TLS connection",
-				"target", target,
-				"error", closeErr.Error(),
-			)
-		}
-	}()
-
-	tlsConn, ok := conn.(*tls.Conn)
-	if !ok {
-		return nil, fmt.Errorf(
-			"%s: %w", target, ErrUnexpectedConnType,
-		)
-	}
-
-	return c.extractCertInfo(tlsConn)
-}
-
-func (c *Checker) buildTLSConfig(
-	sniHostname string,
-) *tls.Config {
-	if c.tlsConfig != nil {
-		cfg := c.tlsConfig.Clone()
-		cfg.ServerName = sniHostname
-
-		return cfg
-	}
-
-	return &tls.Config{
-		ServerName: sniHostname,
-		MinVersion: tls.VersionTLS12,
-	}
-}
-
-func (c *Checker) extractCertInfo(
-	conn *tls.Conn,
-) (*CertificateInfo, error) {
-	state := conn.ConnectionState()
-	if len(state.PeerCertificates) == 0 {
-		return nil, ErrNoPeerCertificates
-	}
-
-	cert := state.PeerCertificates[0]
-
-	sans := make([]string, 0, len(cert.DNSNames)+len(cert.IPAddresses))
-	sans = append(sans, cert.DNSNames...)
-
-	for _, ip := range cert.IPAddresses {
-		sans = append(sans, ip.String())
-	}
-
-	return &CertificateInfo{
-		CommonName:              cert.Subject.CommonName,
-		Issuer:                  cert.Issuer.CommonName,
-		NotAfter:                cert.NotAfter,
-		SubjectAlternativeNames: sans,
-		SerialNumber:            cert.SerialNumber.String(),
-	}, nil
 }

internal/tlscheck/tlscheck_test.go

@@ -1,169 +0,0 @@
-package tlscheck_test
-
-import (
-	"context"
-	"crypto/tls"
-	"net"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-	"time"
-
-	"sneak.berlin/go/dnswatcher/internal/tlscheck"
-)
-
-func startTLSServer(
-	t *testing.T,
-) (*httptest.Server, string, int) {
-	t.Helper()
-
-	srv := httptest.NewTLSServer(
-		http.HandlerFunc(
-			func(w http.ResponseWriter, _ *http.Request) {
-				w.WriteHeader(http.StatusOK)
-			},
-		),
-	)
-
-	addr, ok := srv.Listener.Addr().(*net.TCPAddr)
-	if !ok {
-		t.Fatal("unexpected address type")
-	}
-
-	return srv, addr.IP.String(), addr.Port
-}
-
-func TestCheckCertificateValid(t *testing.T) {
-	t.Parallel()
-
-	srv, ip, port := startTLSServer(t)
-
-	defer srv.Close()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(5*time.Second),
-		tlscheck.WithTLSConfig(&tls.Config{
-			//nolint:gosec // test uses self-signed cert
-			InsecureSkipVerify: true,
-		}),
-		tlscheck.WithPort(port),
-	)
-
-	info, err := checker.CheckCertificate(
-		context.Background(), ip, "localhost",
-	)
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-
-	if info == nil {
-		t.Fatal("expected non-nil CertificateInfo")
-	}
-
-	if info.NotAfter.IsZero() {
-		t.Error("expected non-zero NotAfter")
-	}
-
-	if info.SerialNumber == "" {
-		t.Error("expected non-empty SerialNumber")
-	}
-}
-
-func TestCheckCertificateConnectionRefused(t *testing.T) {
-	t.Parallel()
-
-	lc := &net.ListenConfig{}
-
-	ln, err := lc.Listen(
-		context.Background(), "tcp", "127.0.0.1:0",
-	)
-	if err != nil {
-		t.Fatalf("failed to listen: %v", err)
-	}
-
-	addr, ok := ln.Addr().(*net.TCPAddr)
-	if !ok {
-		t.Fatal("unexpected address type")
-	}
-
-	port := addr.Port
-
-	_ = ln.Close()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(2*time.Second),
-		tlscheck.WithPort(port),
-	)
-
-	_, err = checker.CheckCertificate(
-		context.Background(), "127.0.0.1", "localhost",
-	)
-	if err == nil {
-		t.Fatal("expected error for connection refused")
-	}
-}
-
-func TestCheckCertificateContextCanceled(t *testing.T) {
-	t.Parallel()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(2*time.Second),
-		tlscheck.WithPort(1),
-	)
-
-	_, err := checker.CheckCertificate(
-		ctx, "127.0.0.1", "localhost",
-	)
-	if err == nil {
-		t.Fatal("expected error for canceled context")
-	}
-}
-
-func TestCheckCertificateTimeout(t *testing.T) {
-	t.Parallel()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(1*time.Millisecond),
-		tlscheck.WithPort(1),
-	)
-
-	_, err := checker.CheckCertificate(
-		context.Background(),
-		"192.0.2.1",
-		"example.com",
-	)
-	if err == nil {
-		t.Fatal("expected error for timeout")
-	}
-}
-
-func TestCheckCertificateSANs(t *testing.T) {
-	t.Parallel()
-
-	srv, ip, port := startTLSServer(t)
-
-	defer srv.Close()
-
-	checker := tlscheck.NewStandalone(
-		tlscheck.WithTimeout(5*time.Second),
-		tlscheck.WithTLSConfig(&tls.Config{
-			//nolint:gosec // test uses self-signed cert
-			InsecureSkipVerify: true,
-		}),
-		tlscheck.WithPort(port),
-	)
-
-	info, err := checker.CheckCertificate(
-		context.Background(), ip, "localhost",
-	)
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-
-	if info.CommonName == "" && len(info.SubjectAlternativeNames) == 0 {
-		t.Error("expected CN or SANs to be populated")
-	}
-}

internal/watcher/interfaces.go

@@ -4,7 +4,6 @@ package watcher
 import (
 	"context"
 
-	"sneak.berlin/go/dnswatcher/internal/portcheck"
 	"sneak.berlin/go/dnswatcher/internal/tlscheck"
 )
 
@@ -37,7 +36,7 @@ type PortChecker interface {
 		ctx context.Context,
 		address string,
 		port int,
-	) (*portcheck.PortResult, error)
+	) (bool, error)
 }
 
 // TLSChecker inspects TLS certificates.

internal/watcher/watcher.go

@@ -6,7 +6,6 @@ import (
 	"log/slog"
 	"sort"
 	"strings"
-	"sync"
 	"time"
 
 	"go.uber.org/fx"
@@ -50,8 +49,6 @@ type Watcher struct {
 	notify    Notifier
 	cancel    context.CancelFunc
 	firstRun  bool
-	expiryNotifiedMu sync.Mutex
-	expiryNotified   map[string]time.Time
 }
 
 // New creates a new Watcher instance wired into the fx lifecycle.
@@ -68,7 +65,6 @@ func New(
 		tlsCheck:  params.TLSCheck,
 		notify:    params.Notify,
 		firstRun:  true,
-		expiryNotified: make(map[string]time.Time),
 	}
 
 	lifecycle.Append(fx.Hook{
@@ -112,7 +108,6 @@ func NewForTest(
 		tlsCheck:  tc,
 		notify:    n,
 		firstRun:  true,
-		expiryNotified: make(map[string]time.Time),
 	}
 }
 
@@ -211,28 +206,6 @@ func (w *Watcher) checkDomain(
 		Nameservers: nameservers,
 		LastChecked: now,
 	})
-
-	// Also look up A/AAAA records for the apex domain so that
-	// port and TLS checks (which read HostnameState) can find
-	// the domain's IP addresses.
-	records, err := w.resolver.LookupAllRecords(ctx, domain)
-	if err != nil {
-		w.log.Error(
-			"failed to lookup records for domain",
-			"domain", domain,
-			"error", err,
-		)
-
-		return
-	}
-
-	prevHS, hasPrevHS := w.state.GetHostnameState(domain)
-	if hasPrevHS && !w.firstRun {
-		w.detectHostnameChanges(ctx, domain, prevHS, records)
-	}
-
-	newState := buildHostnameState(records, now)
-	w.state.SetHostnameState(domain, newState)
 }
 
 func (w *Watcher) detectNSChanges(
@@ -504,7 +477,7 @@ func (w *Watcher) checkSinglePort(
 	port int,
 	hostname string,
 ) {
-	result, err := w.portCheck.CheckPort(ctx, ip, port)
+	open, err := w.portCheck.CheckPort(ctx, ip, port)
 	if err != nil {
 		w.log.Error(
 			"port check failed",
@@ -520,9 +493,9 @@ func (w *Watcher) checkSinglePort(
 	now := time.Now().UTC()
 	prev, hasPrev := w.state.GetPortState(key)
 
-	if hasPrev && !w.firstRun && prev.Open != result.Open {
+	if hasPrev && !w.firstRun && prev.Open != open {
 		stateStr := "closed"
-		if result.Open {
+		if open {
 			stateStr = "open"
 		}
 
@@ -540,7 +513,7 @@ func (w *Watcher) checkSinglePort(
 	}
 
 	w.state.SetPortState(key, &state.PortState{
-		Open:        result.Open,
+		Open:        open,
 		Hostname:    hostname,
 		LastChecked: now,
 	})
@@ -718,22 +691,6 @@ func (w *Watcher) checkTLSExpiry(
 		return
 	}
 
-	// Deduplicate expiry warnings: don't re-notify for the same
-	// hostname within the TLS check interval.
-	dedupKey := fmt.Sprintf("expiry:%s:%s", hostname, ip)
-
-	w.expiryNotifiedMu.Lock()
-
-	lastNotified, seen := w.expiryNotified[dedupKey]
-	if seen && time.Since(lastNotified) < w.config.TLSInterval {
-		w.expiryNotifiedMu.Unlock()
-
-		return
-	}
-
-	w.expiryNotified[dedupKey] = time.Now()
-	w.expiryNotifiedMu.Unlock()
-
 	msg := fmt.Sprintf(
 		"Host: %s\nIP: %s\nCN: %s\n"+
 			"Expires: %s (%.0f days)",

internal/watcher/watcher_test.go

@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"sneak.berlin/go/dnswatcher/internal/config"
-	"sneak.berlin/go/dnswatcher/internal/portcheck"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/tlscheck"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
@@ -110,20 +109,24 @@ func (m *mockPortChecker) CheckPort(
 	_ context.Context,
 	address string,
 	port int,
-) (*portcheck.PortResult, error) {
+) (bool, error) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 
 	m.calls++
 
 	if m.err != nil {
-		return nil, m.err
+		return false, m.err
 	}
 
 	key := fmt.Sprintf("%s:%d", address, port)
-	open := m.results[key]
+	open, ok := m.results[key]
 
-	return &portcheck.PortResult{Open: open}, nil
+	if !ok {
+		return false, nil
+	}
+
+	return open, nil
 }
 
 type mockTLSChecker struct {
@@ -273,10 +276,6 @@ func setupBaselineMocks(deps *testDeps) {
 		"ns1.example.com.",
 		"ns2.example.com.",
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
-		"ns2.example.com.": {"A": {"93.184.216.34"}},
-	}
 	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
 		"ns1.example.com.": {"A": {"93.184.216.34"}},
 		"ns2.example.com.": {"A": {"93.184.216.34"}},
@@ -294,14 +293,6 @@ func setupBaselineMocks(deps *testDeps) {
 			"www.example.com",
 		},
 	}
-	deps.tlsChecker.certs["93.184.216.34:example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "example.com",
-		Issuer:     "DigiCert",
-		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
-		SubjectAlternativeNames: []string{
-			"example.com",
-		},
-	}
 }
 
 func assertNoNotifications(
@@ -334,74 +325,14 @@ func assertStatePopulated(
 		)
 	}
 
-	// Hostnames includes both explicit hostnames and domains
+	if len(snap.Hostnames) != 1 {
-	// (domains now also get hostname state for port/TLS checks).
-	if len(snap.Hostnames) < 1 {
 		t.Errorf(
-			"expected at least 1 hostname in state, got %d",
+			"expected 1 hostname in state, got %d",
 			len(snap.Hostnames),
 		)
 	}
 }
 
-func TestDomainPortAndTLSChecks(t *testing.T) {
-	t.Parallel()
-
-	cfg := defaultTestConfig(t)
-	cfg.Domains = []string{"example.com"}
-
-	w, deps := newTestWatcher(t, cfg)
-
-	deps.resolver.nsRecords["example.com"] = []string{
-		"ns1.example.com.",
-	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"93.184.216.34"}},
-	}
-	deps.portChecker.results["93.184.216.34:80"] = true
-	deps.portChecker.results["93.184.216.34:443"] = true
-	deps.tlsChecker.certs["93.184.216.34:example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "example.com",
-		Issuer:     "DigiCert",
-		NotAfter:   time.Now().Add(90 * 24 * time.Hour),
-		SubjectAlternativeNames: []string{
-			"example.com",
-		},
-	}
-
-	w.RunOnce(t.Context())
-
-	snap := deps.state.GetSnapshot()
-
-	// Domain should have port state populated
-	if len(snap.Ports) == 0 {
-		t.Error("expected port state for domain, got none")
-	}
-
-	// Domain should have certificate state populated
-	if len(snap.Certificates) == 0 {
-		t.Error("expected certificate state for domain, got none")
-	}
-
-	// Verify port checker was actually called
-	deps.portChecker.mu.Lock()
-	calls := deps.portChecker.calls
-	deps.portChecker.mu.Unlock()
-
-	if calls == 0 {
-		t.Error("expected port checker to be called for domain")
-	}
-
-	// Verify TLS checker was actually called
-	deps.tlsChecker.mu.Lock()
-	tlsCalls := deps.tlsChecker.calls
-	deps.tlsChecker.mu.Unlock()
-
-	if tlsCalls == 0 {
-		t.Error("expected TLS checker to be called for domain")
-	}
-}
-
 func TestNSChangeDetection(t *testing.T) {
 	t.Parallel()
 
@@ -414,12 +345,6 @@ func TestNSChangeDetection(t *testing.T) {
 		"ns1.example.com.",
 		"ns2.example.com.",
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
-		"ns2.example.com.": {"A": {"1.2.3.4"}},
-	}
-	deps.portChecker.results["1.2.3.4:80"] = false
-	deps.portChecker.results["1.2.3.4:443"] = false
 
 	ctx := t.Context()
 	w.RunOnce(ctx)
@@ -429,10 +354,6 @@ func TestNSChangeDetection(t *testing.T) {
 		"ns1.example.com.",
 		"ns3.example.com.",
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
-		"ns3.example.com.": {"A": {"1.2.3.4"}},
-	}
 	deps.resolver.mu.Unlock()
 
 	w.RunOnce(ctx)
@@ -588,61 +509,6 @@ func TestTLSExpiryWarning(t *testing.T) {
 	}
 }
 
-func TestTLSExpiryWarningDedup(t *testing.T) {
-	t.Parallel()
-
-	cfg := defaultTestConfig(t)
-	cfg.Hostnames = []string{"www.example.com"}
-	cfg.TLSInterval = 24 * time.Hour
-
-	w, deps := newTestWatcher(t, cfg)
-
-	deps.resolver.allRecords["www.example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
-	}
-	deps.resolver.ipAddresses["www.example.com"] = []string{
-		"1.2.3.4",
-	}
-	deps.portChecker.results["1.2.3.4:80"] = true
-	deps.portChecker.results["1.2.3.4:443"] = true
-	deps.tlsChecker.certs["1.2.3.4:www.example.com"] = &tlscheck.CertificateInfo{
-		CommonName: "www.example.com",
-		Issuer:     "DigiCert",
-		NotAfter:   time.Now().Add(3 * 24 * time.Hour),
-		SubjectAlternativeNames: []string{
-			"www.example.com",
-		},
-	}
-
-	ctx := t.Context()
-
-	// First run = baseline, no notifications
-	w.RunOnce(ctx)
-
-	// Second run should fire one expiry warning
-	w.RunOnce(ctx)
-
-	// Third run should NOT fire another warning (dedup)
-	w.RunOnce(ctx)
-
-	notifications := deps.notifier.getNotifications()
-
-	expiryCount := 0
-
-	for _, n := range notifications {
-		if n.Title == "TLS Expiry Warning: www.example.com" {
-			expiryCount++
-		}
-	}
-
-	if expiryCount != 1 {
-		t.Errorf(
-			"expected exactly 1 expiry warning (dedup), got %d",
-			expiryCount,
-		)
-	}
-}
-
 func TestGracefulShutdown(t *testing.T) {
 	t.Parallel()
 
@@ -656,11 +522,6 @@ func TestGracefulShutdown(t *testing.T) {
 	deps.resolver.nsRecords["example.com"] = []string{
 		"ns1.example.com.",
 	}
-	deps.resolver.allRecords["example.com"] = map[string]map[string][]string{
-		"ns1.example.com.": {"A": {"1.2.3.4"}},
-	}
-	deps.portChecker.results["1.2.3.4:80"] = false
-	deps.portChecker.results["1.2.3.4:443"] = false
 
 	ctx, cancel := context.WithCancel(t.Context())