chore(#130): mark self-review findings as addressed in TODO.md

validateurl.go is VCS-generic but imported gitea.IsBlockedIP, creating an
unexpected generic→Gitea-specific dependency. Extract IsBlockedIP and its
CIDR list to internal/netutil/ipcheck.go (a neutral shared package).

- gitea/ipcheck.go becomes a thin forwarding wrapper (preserves API compat
  for callers within the gitea package)
- gitea/ipcheck_test.go replaced with a forwarding smoke test; full coverage
  moves to internal/netutil/ipcheck_test.go
- validateurl.go now imports internal/netutil directly

.gitea/actions/review/action.yml

@@ -476,6 +476,7 @@ runs:
       shell: bash
       env:
         VCS_URL: ${{ steps.version.outputs.server_url }}
+        VCS_TYPE: ${{ steps.version.outputs.vcs_type }}
         GITEA_REPO: ${{ inputs.repo || github.repository }}
         PR_NUMBER: ${{ inputs.pr-number || github.event.pull_request.number }}
         REVIEWER_TOKEN: ${{ inputs.reviewer-token }}

README.md

@@ -285,7 +285,7 @@ review-bot \
   --vcs-url https://gitea.example.com \
   --repo owner/name \
   --pr 42 \
-  --reviewer-token "$GITEA_TOKEN" \
+  --reviewer-token "$REVIEWER_TOKEN" \
   --reviewer-name "code-review" \
   --llm-base-url https://api.openai.com/v1 \
   --llm-api-key "$OPENAI_API_KEY" \
@@ -300,7 +300,8 @@ All flags have environment variable equivalents:
 | Flag | Env Var |
 |------|---------|
 | `--vcs-url` | `VCS_URL` (fallback: `GITEA_URL`) |
-| `--repo` | `GITEA_REPO` |
+| `--vcs-type` | `VCS_TYPE` (auto-detected from URL if not set; `gitea` or `github`) |
+| `--repo` | `GITEA_REPO` (also accepted: set `GITEA_REPO` for Gitea; VCS-agnostic `REPO` coming) |
 | `--pr` | `PR_NUMBER` |
 | `--reviewer-token` | `REVIEWER_TOKEN` |
 | `--reviewer-name` | `REVIEWER_NAME` |

TODO.md

@@ -77,3 +77,12 @@ All old worktrees cleaned up. Ready for new issue work.
 - **Cron ID:** 5342ac81-4bbc-4e4c-a123-347a7788d50c
 - **Scheduled:** Every 4 hours
 - **Last health check:** 2026-05-14 20:10 UTC (✅ all healthy)
+
+## Self-Review: review-bot-issue-130-work — 2026-05-14
+
+### Verdict: NEEDS_WORK
+
+- [x] [completeness] `VCS_TYPE` env var is detected in `main.go` but **not passed from `action.yml`'s `Run review` step** to the binary. The binary falls back to a URL heuristic (`github.com` / `github.concur.com` substrings), which will silently misclassify any GitHub Enterprise Server whose hostname does not contain `github`. The action already has `vcs_type` as a step output — it should be passed as `VCS_TYPE: ${{ steps.version.outputs.vcs_type }}` in the `Run review` env block.
+- [x] [completeness] `README.md` still references `GITEA_REPO` and `$GITEA_TOKEN` in the CLI example (line ~288) and the env var table (line ~303). Now that the binary supports GitHub too, these should be renamed to VCS-agnostic names (`VCS_REPO`/`REPO`, `VCS_TOKEN`/`REVIEWER_TOKEN`) or at minimum the env var table should note GitHub support.
+- [x] [fit] `vcsReviewComment.NewPosition` field comment says "Gitea: absolute line; GitHub: diff hunk position" but in `githubVCSAdapter.PostReview` it is actually mapped to `Line` (absolute line) + `Side: "RIGHT"`, not to `Position` (hunk position). The field name and comment are now slightly misleading — the field means "new line number" for Gitea and is repurposed as "absolute line" for GitHub. Consider renaming to `Line` or `NewLine` with a clearer comment explaining the per-backend semantics.
+- [x] [instinct] `validateurl.go` imports `gitea` package for `gitea.IsBlockedIP` — this creates a dependency from the GitHub-generic `validateurl.go` on the Gitea-specific package. The `IsBlockedIP` function is a general networking utility. Consider moving it to a shared `internal/netutil` package (or keeping it in `gitea` and accepting the coupling), but the current import is an unexpected relationship.

cmd/review-bot/main.go

@@ -466,7 +466,7 @@ func main() {
 		if f.File != "" && f.Line > 0 && diffRanges.Contains(f.File, f.Line) {
 			inlineComments = append(inlineComments, vcsReviewComment{
 				Path:    f.File,
-				NewPosition: int64(f.Line),
+				NewLine: int64(f.Line),
 				Body:    fmt.Sprintf("**[%s]** %s", f.Severity, f.Finding),
 			})
 		}

cmd/review-bot/validateurl.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"time"
 
-	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/internal/netutil"
 )
 
 // runValidateURL implements the `review-bot validate-url <url>` subcommand.
@@ -114,7 +114,7 @@ func validateURL(rawURL string) error {
 	}
 
 	for _, a := range addrs {
-		if gitea.IsBlockedIP(a.IP) {
+		if netutil.IsBlockedIP(a.IP) {
 			return &validateError{
 				code:    1,
 				message: fmt.Sprintf("blocked: %q resolves to private/reserved IP %s", host, a.IP),

cmd/review-bot/vcs.go

@@ -84,7 +84,7 @@ type vcsCommitStatus struct {
 // vcsReviewComment is an inline review comment.
 type vcsReviewComment struct {
 	Path    string
-	NewPosition int64 // Gitea: absolute line; GitHub: diff hunk position
+	NewLine int64 // absolute line number on the new (right) side of the diff, used by both Gitea and GitHub adapters
 	Body    string
 }
 
@@ -176,7 +176,7 @@ func (a *giteaVCSAdapter) GetAllFilesInPath(ctx context.Context, owner, repo, pa
 func (a *giteaVCSAdapter) PostReview(ctx context.Context, owner, repo string, number int, event, body, commitID string, comments []vcsReviewComment) (*vcsReview, error) {
 	gc := make([]gitea.ReviewComment, len(comments))
 	for i, c := range comments {
-		gc[i] = gitea.ReviewComment{Path: c.Path, NewPosition: c.NewPosition, Body: c.Body}
+		gc[i] = gitea.ReviewComment{Path: c.Path, NewPosition: c.NewLine, Body: c.Body}
 	}
 	r, err := a.c.PostReview(ctx, owner, repo, number, event, body, commitID, gc)
 	if err != nil {
@@ -311,14 +311,12 @@ func (a *githubVCSAdapter) GetAllFilesInPath(ctx context.Context, owner, repo, p
 func (a *githubVCSAdapter) PostReview(ctx context.Context, owner, repo string, number int, event, body, commitID string, comments []vcsReviewComment) (*vcsReview, error) {
 	gc := make([]github.ReviewComment, len(comments))
 	for i, c := range comments {
-		// GitHub inline comments use diff hunk "position", not absolute line numbers.
+		// GitHub inline comments use Line+Side (absolute line on the RIGHT side).
-		// NewPosition from gitea diff parsing gives absolute line numbers, which
+		// NewLine from diff parsing gives absolute new-file line numbers.
-		// will not match GitHub's position values. For initial GitHub support, we
-		// attach comments with Line+Side (absolute line on the RIGHT side) instead.
 		// Comments that cannot be mapped will be omitted (GitHub rejects invalid positions).
 		gc[i] = github.ReviewComment{
 			Path: c.Path,
-			Line: c.NewPosition,
+			Line: c.NewLine,
 			Side: "RIGHT",
 			Body: c.Body,
 		}

gitea/ipcheck.go

@@ -1,91 +1,22 @@
 // Package gitea provides a client for the Gitea API.
-// ipcheck.go implements IP-level SSRF protection by checking resolved addresses
+// ipcheck.go re-exports the IsBlockedIP function from internal/netutil for use
-// against known blocked CIDR ranges (RFC1918, loopback, link-local, etc.).
+// by this package's safe dialer (client.go) and for backward compatibility with
+// any callers that previously imported it from here.
+//
+// The implementation has moved to internal/netutil so it can be shared with the
+// validate-url subcommand (cmd/review-bot/validateurl.go) without creating a
+// dependency from VCS-generic code on the Gitea-specific package.
 package gitea
 
 import (
-	"fmt"
 	"net"
+
+	"gitea.weiker.me/rodin/review-bot/internal/netutil"
 )
 
-// blockedCIDRStrings is the canonical list of CIDR strings that should never
-// be contacted by review-bot. See IsBlockedIP for the full list of covered
-// address families.
-//
-// These are hard-coded literals: any parse failure is a programming error.
-// Validity is verified by TestBlockedCIDRsValid in ipcheck_test.go.
-var blockedCIDRStrings = []string{
-	// IPv4 loopback
-	"127.0.0.0/8",
-	// IPv4 unspecified / "this network"
-	"0.0.0.0/8",
-	// RFC1918 private ranges
-	"10.0.0.0/8",
-	"172.16.0.0/12",
-	"192.168.0.0/16",
-	// IPv4 link-local (APIPA, also used by AWS instance metadata 169.254.169.254)
-	"169.254.0.0/16",
-	// IPv4 shared address space (RFC6598, carrier-grade NAT)
-	"100.64.0.0/10",
-	// IPv4 multicast
-	"224.0.0.0/4",
-	// IPv4 reserved / broadcast
-	"240.0.0.0/4",
-	// IPv6 loopback
-	"::1/128",
-	// IPv6 unspecified
-	"::/128",
-	// IPv6 link-local
-	"fe80::/10",
-	// IPv6 unique local (ULA) — RFC4193
-	"fc00::/7",
-	// IPv6 multicast
-	"ff00::/8",
-}
-
-// blockedCIDRs is the parsed form of blockedCIDRStrings.
-// Any entry that fails to parse is recorded in blockedCIDRParseErrors instead
-// of panicking; tests verify this slice is always empty via TestBlockedCIDRsValid.
-var (
-	blockedCIDRs           []*net.IPNet
-	blockedCIDRParseErrors []string
-)
-
-func init() {
-	blockedCIDRs = make([]*net.IPNet, 0, len(blockedCIDRStrings))
-	for _, r := range blockedCIDRStrings {
-		_, cidr, err := net.ParseCIDR(r)
-		if err != nil {
-			// Record the error rather than panicking; TestBlockedCIDRsValid
-			// will catch this during tests, and the CI build will fail.
-			blockedCIDRParseErrors = append(blockedCIDRParseErrors,
-				fmt.Sprintf("ipcheck: invalid built-in CIDR %q: %v", r, err))
-			continue
-		}
-		blockedCIDRs = append(blockedCIDRs, cidr)
-	}
-}
-
 // IsBlockedIP reports whether ip is in a blocked address range.
-// It is exported for use by the validate-url subcommand and tests outside
+// It delegates to internal/netutil.IsBlockedIP; see that function for the full
-// this package.
+// list of blocked ranges and IPv6-mapped IPv4 normalization behavior.
-//
-// IPv6-mapped IPv4 addresses (e.g. ::ffff:192.168.1.1) are normalized to their
-// IPv4 form before checking so that IPv4 CIDRs catch them.
-//
-// Based on:
-//   - RFC1918 private ranges
-//   - RFC5735 / RFC4193 special-use IPv4/IPv6 ranges
-//   - RFC4291 IPv6 link-local / loopback
 func IsBlockedIP(ip net.IP) bool {
-	// Normalize IPv6-mapped IPv4 addresses (::ffff:x.x.x.x) to plain IPv4.
+	return netutil.IsBlockedIP(ip)
-	if v4 := ip.To4(); v4 != nil {
-		ip = v4
-	}
-	for _, cidr := range blockedCIDRs {
-		if cidr.Contains(ip) {
-			return true
-		}
-	}
-	return false
 }

gitea/ipcheck_test.go

@@ -3,142 +3,35 @@ package gitea
 import (
 	"net"
 	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/internal/netutil"
 )
 
-func TestIsBlockedIP(t *testing.T) {
+// TestIsBlockedIPForwarding verifies that gitea.IsBlockedIP correctly forwards
-	blocked := []struct {
+// to internal/netutil.IsBlockedIP. Full coverage of the blocking logic lives in
-		name string
+// internal/netutil/ipcheck_test.go.
+func TestIsBlockedIPForwarding(t *testing.T) {
+	cases := []struct {
 		ip      string
+		blocked bool
 	}{
-		// IPv4 loopback
+		{"127.0.0.1", true},        // loopback — must be blocked
-		{"loopback 127.0.0.1", "127.0.0.1"},
+		{"192.168.1.1", true},      // RFC1918 — must be blocked
-		{"loopback 127.0.0.2", "127.0.0.2"},
+		{"8.8.8.8", false},         // public — must not be blocked
-		{"loopback 127.255.255.255", "127.255.255.255"},
+		{"2001:4860:4860::8888", false}, // public IPv6 — must not be blocked
-		// IPv4 unspecified
-		{"unspecified 0.0.0.0", "0.0.0.0"},
-		{"unspecified 0.1.2.3", "0.1.2.3"},
-		// RFC1918
-		{"RFC1918 10.0.0.1", "10.0.0.1"},
-		{"RFC1918 10.255.255.255", "10.255.255.255"},
-		{"RFC1918 172.16.0.1", "172.16.0.1"},
-		{"RFC1918 172.31.255.255", "172.31.255.255"},
-		{"RFC1918 192.168.0.1", "192.168.0.1"},
-		{"RFC1918 192.168.255.255", "192.168.255.255"},
-		// Link-local (APIPA / AWS metadata)
-		{"link-local 169.254.0.1", "169.254.0.1"},
-		{"link-local 169.254.169.254", "169.254.169.254"},
-		// Shared address space (carrier-grade NAT)
-		{"CGN 100.64.0.1", "100.64.0.1"},
-		{"CGN 100.127.255.255", "100.127.255.255"},
-		// Multicast
-		{"multicast 224.0.0.1", "224.0.0.1"},
-		{"multicast 239.255.255.255", "239.255.255.255"},
-		// Reserved
-		{"reserved 240.0.0.1", "240.0.0.1"},
-		{"broadcast 255.255.255.255", "255.255.255.255"},
-		// IPv6 loopback
-		{"IPv6 loopback ::1", "::1"},
-		// IPv6 unspecified
-		{"IPv6 unspecified ::", "::"},
-		// IPv6 link-local
-		{"IPv6 link-local fe80::1", "fe80::1"},
-		{"IPv6 link-local fe80::dead:beef", "fe80::dead:beef"},
-		// IPv6 ULA
-		{"IPv6 ULA fc00::1", "fc00::1"},
-		{"IPv6 ULA fd00::1", "fd00::1"},
-		// IPv6 multicast
-		{"IPv6 multicast ff02::1", "ff02::1"},
 	}
-
+	for _, tc := range cases {
-	for _, tc := range blocked {
-		t.Run(tc.name, func(t *testing.T) {
 		ip := net.ParseIP(tc.ip)
 		if ip == nil {
 			t.Fatalf("failed to parse IP %q", tc.ip)
 		}
-			if !IsBlockedIP(ip) {
+		got := IsBlockedIP(ip)
-				t.Errorf("IsBlockedIP(%q) = false, want true", tc.ip)
+		want := netutil.IsBlockedIP(ip)
+		if got != want {
+			t.Errorf("gitea.IsBlockedIP(%q) = %v, netutil.IsBlockedIP = %v: forwarding mismatch", tc.ip, got, want)
 		}
-		})
+		if got != tc.blocked {
-	}
+			t.Errorf("gitea.IsBlockedIP(%q) = %v, want %v", tc.ip, got, tc.blocked)
-
-	allowed := []struct {
-		name string
-		ip   string
-	}{
-		{"public 8.8.8.8", "8.8.8.8"},
-		{"public 1.1.1.1", "1.1.1.1"},
-		{"public 198.51.100.1", "198.51.100.1"}, // RFC5737 TEST-NET-2 — a documentation-only range;
-					// not assigned to any real host, but intentionally left unblocked here because
-					// it has no special routing treatment (unlike RFC1918/loopback/link-local) and
-					// blocking it would require tracking every RFC5737 range without meaningful
-					// security benefit (no server should ever listen on a TEST-NET address).
-		{"public 151.101.1.1", "151.101.1.1"},        // Fastly
-		{"public IPv6 2001:4860:4860::8888", "2001:4860:4860::8888"}, // Google DNS
-		{"public IPv6 2606:4700:4700::1111", "2606:4700:4700::1111"}, // Cloudflare DNS
-	}
-
-	for _, tc := range allowed {
-		t.Run(tc.name, func(t *testing.T) {
-			ip := net.ParseIP(tc.ip)
-			if ip == nil {
-				t.Fatalf("failed to parse IP %q", tc.ip)
-			}
-			if IsBlockedIP(ip) {
-				t.Errorf("IsBlockedIP(%q) = true, want false", tc.ip)
-			}
-		})
-	}
-}
-
-func TestIsBlockedIPv6MappedIPv4(t *testing.T) {
-	// ::ffff:192.168.1.1 is an IPv6-mapped IPv4 address — should be blocked as RFC1918.
-	// Construct it manually as a 16-byte IP.
-	mapped := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 192, 168, 1, 1}
-	if !IsBlockedIP(mapped) {
-		t.Errorf("IsBlockedIP(::ffff:192.168.1.1) = false, want true (IPv6-mapped IPv4 must be normalized)")
-	}
-
-	// ::ffff:8.8.8.8 — IPv6-mapped public IP — should be allowed.
-	mappedPublic := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 8, 8, 8, 8}
-	if IsBlockedIP(mappedPublic) {
-		t.Errorf("IsBlockedIP(::ffff:8.8.8.8) = true, want false")
-	}
-}
-
-func TestIsBlockedIPEdgeCases(t *testing.T) {
-	// The boundary between RFC1918 and public ranges.
-	// 172.15.255.255 is NOT private (just below 172.16.0.0/12).
-	notPrivate := net.ParseIP("172.15.255.255")
-	if IsBlockedIP(notPrivate) {
-		t.Errorf("IsBlockedIP(172.15.255.255) = true, want false (outside 172.16.0.0/12)")
-	}
-	// 172.32.0.0 is NOT private (just above 172.31.255.255).
-	notPrivate2 := net.ParseIP("172.32.0.0")
-	if IsBlockedIP(notPrivate2) {
-		t.Errorf("IsBlockedIP(172.32.0.0) = true, want false (outside 172.16.0.0/12)")
-	}
-	// CGN: 100.63.255.255 is NOT in 100.64.0.0/10.
-	notCGN := net.ParseIP("100.63.255.255")
-	if IsBlockedIP(notCGN) {
-		t.Errorf("IsBlockedIP(100.63.255.255) = true, want false (outside 100.64.0.0/10)")
-	}
-	// CGN: 100.128.0.0 is NOT in 100.64.0.0/10.
-	notCGN2 := net.ParseIP("100.128.0.0")
-	if IsBlockedIP(notCGN2) {
-		t.Errorf("IsBlockedIP(100.128.0.0) = true, want false (outside 100.64.0.0/10)")
-	}
-}
-
-// TestBlockedCIDRsValid verifies that all entries in blockedCIDRStrings parse
-// successfully. This catches programming errors in the CIDR list without
-// requiring a startup panic. The init() function records parse failures in
-// blockedCIDRParseErrors rather than panicking; this test makes those failures
-// visible as test failures during CI.
-func TestBlockedCIDRsValid(t *testing.T) {
-	if len(blockedCIDRParseErrors) > 0 {
-		for _, msg := range blockedCIDRParseErrors {
-			t.Errorf("CIDR parse error: %s", msg)
 		}
 	}
 }

internal/netutil/ipcheck.go

@@ -0,0 +1,97 @@
+// Package netutil provides shared network utilities for review-bot.
+// ipcheck.go implements IP-level SSRF protection by checking resolved addresses
+// against known blocked CIDR ranges (RFC1918, loopback, link-local, etc.).
+package netutil
+
+import (
+	"fmt"
+	"net"
+)
+
+// blockedCIDRStrings is the canonical list of CIDR strings that should never
+// be contacted by review-bot. See IsBlockedIP for the full list of covered
+// address families.
+//
+// These are hard-coded literals: any parse failure is a programming error.
+// Validity is verified by TestBlockedCIDRsValid in ipcheck_test.go.
+var blockedCIDRStrings = []string{
+	// IPv4 loopback
+	"127.0.0.0/8",
+	// IPv4 unspecified / "this network"
+	"0.0.0.0/8",
+	// RFC1918 private ranges
+	"10.0.0.0/8",
+	"172.16.0.0/12",
+	"192.168.0.0/16",
+	// IPv4 link-local (APIPA, also used by AWS instance metadata 169.254.169.254)
+	"169.254.0.0/16",
+	// IPv4 shared address space (RFC6598, carrier-grade NAT)
+	"100.64.0.0/10",
+	// IPv4 multicast
+	"224.0.0.0/4",
+	// IPv4 reserved / broadcast
+	"240.0.0.0/4",
+	// IPv6 loopback
+	"::1/128",
+	// IPv6 unspecified
+	"::/128",
+	// IPv6 link-local
+	"fe80::/10",
+	// IPv6 unique local (ULA) — RFC4193
+	"fc00::/7",
+	// IPv6 multicast
+	"ff00::/8",
+}
+
+// blockedCIDRs is the parsed form of blockedCIDRStrings.
+// Any entry that fails to parse is recorded in blockedCIDRParseErrors instead
+// of panicking; tests verify this slice is always empty via TestBlockedCIDRsValid.
+var (
+	blockedCIDRs           []*net.IPNet
+	blockedCIDRParseErrors []string
+)
+
+func init() {
+	blockedCIDRs = make([]*net.IPNet, 0, len(blockedCIDRStrings))
+	for _, r := range blockedCIDRStrings {
+		_, cidr, err := net.ParseCIDR(r)
+		if err != nil {
+			// Record the error rather than panicking; TestBlockedCIDRsValid
+			// will catch this during tests, and the CI build will fail.
+			blockedCIDRParseErrors = append(blockedCIDRParseErrors,
+				fmt.Sprintf("ipcheck: invalid built-in CIDR %q: %v", r, err))
+			continue
+		}
+		blockedCIDRs = append(blockedCIDRs, cidr)
+	}
+}
+
+// BlockedCIDRParseErrors returns any errors encountered parsing the built-in
+// CIDR list. In correct code this will always be empty; tests assert it is.
+func BlockedCIDRParseErrors() []string {
+	return blockedCIDRParseErrors
+}
+
+// IsBlockedIP reports whether ip is in a blocked address range.
+// It is exported for use by the gitea package's safe dialer, the validate-url
+// subcommand, and tests outside this package.
+//
+// IPv6-mapped IPv4 addresses (e.g. ::ffff:192.168.1.1) are normalized to their
+// IPv4 form before checking so that IPv4 CIDRs catch them.
+//
+// Based on:
+//   - RFC1918 private ranges
+//   - RFC5735 / RFC4193 special-use IPv4/IPv6 ranges
+//   - RFC4291 IPv6 link-local / loopback
+func IsBlockedIP(ip net.IP) bool {
+	// Normalize IPv6-mapped IPv4 addresses (::ffff:x.x.x.x) to plain IPv4.
+	if v4 := ip.To4(); v4 != nil {
+		ip = v4
+	}
+	for _, cidr := range blockedCIDRs {
+		if cidr.Contains(ip) {
+			return true
+		}
+	}
+	return false
+}

internal/netutil/ipcheck_test.go

@@ -0,0 +1,142 @@
+package netutil
+
+import (
+	"net"
+	"testing"
+)
+
+func TestIsBlockedIP(t *testing.T) {
+	blocked := []struct {
+		name string
+		ip   string
+	}{
+		// IPv4 loopback
+		{"loopback 127.0.0.1", "127.0.0.1"},
+		{"loopback 127.0.0.2", "127.0.0.2"},
+		{"loopback 127.255.255.255", "127.255.255.255"},
+		// IPv4 unspecified
+		{"unspecified 0.0.0.0", "0.0.0.0"},
+		{"unspecified 0.1.2.3", "0.1.2.3"},
+		// RFC1918
+		{"RFC1918 10.0.0.1", "10.0.0.1"},
+		{"RFC1918 10.255.255.255", "10.255.255.255"},
+		{"RFC1918 172.16.0.1", "172.16.0.1"},
+		{"RFC1918 172.31.255.255", "172.31.255.255"},
+		{"RFC1918 192.168.0.1", "192.168.0.1"},
+		{"RFC1918 192.168.255.255", "192.168.255.255"},
+		// Link-local (APIPA / AWS metadata)
+		{"link-local 169.254.0.1", "169.254.0.1"},
+		{"link-local 169.254.169.254", "169.254.169.254"},
+		// Shared address space (carrier-grade NAT)
+		{"CGN 100.64.0.1", "100.64.0.1"},
+		{"CGN 100.127.255.255", "100.127.255.255"},
+		// Multicast
+		{"multicast 224.0.0.1", "224.0.0.1"},
+		{"multicast 239.255.255.255", "239.255.255.255"},
+		// Reserved
+		{"reserved 240.0.0.1", "240.0.0.1"},
+		{"broadcast 255.255.255.255", "255.255.255.255"},
+		// IPv6 loopback
+		{"IPv6 loopback ::1", "::1"},
+		// IPv6 unspecified
+		{"IPv6 unspecified ::", "::"},
+		// IPv6 link-local
+		{"IPv6 link-local fe80::1", "fe80::1"},
+		{"IPv6 link-local fe80::dead:beef", "fe80::dead:beef"},
+		// IPv6 ULA
+		{"IPv6 ULA fc00::1", "fc00::1"},
+		{"IPv6 ULA fd00::1", "fd00::1"},
+		// IPv6 multicast
+		{"IPv6 multicast ff02::1", "ff02::1"},
+	}
+
+	for _, tc := range blocked {
+		t.Run(tc.name, func(t *testing.T) {
+			ip := net.ParseIP(tc.ip)
+			if ip == nil {
+				t.Fatalf("failed to parse IP %q", tc.ip)
+			}
+			if !IsBlockedIP(ip) {
+				t.Errorf("IsBlockedIP(%q) = false, want true", tc.ip)
+			}
+		})
+	}
+
+	allowed := []struct {
+		name string
+		ip   string
+	}{
+		{"public 8.8.8.8", "8.8.8.8"},
+		{"public 1.1.1.1", "1.1.1.1"},
+		{"public 198.51.100.1", "198.51.100.1"}, // RFC5737 TEST-NET-2 — a documentation-only range;
+		// not assigned to any real host, but intentionally left unblocked here because
+		// it has no special routing treatment (unlike RFC1918/loopback/link-local) and
+		// blocking it would require tracking every RFC5737 range without meaningful
+		// security benefit (no server should ever listen on a TEST-NET address).
+		{"public 151.101.1.1", "151.101.1.1"},                        // Fastly
+		{"public IPv6 2001:4860:4860::8888", "2001:4860:4860::8888"}, // Google DNS
+		{"public IPv6 2606:4700:4700::1111", "2606:4700:4700::1111"}, // Cloudflare DNS
+	}
+
+	for _, tc := range allowed {
+		t.Run(tc.name, func(t *testing.T) {
+			ip := net.ParseIP(tc.ip)
+			if ip == nil {
+				t.Fatalf("failed to parse IP %q", tc.ip)
+			}
+			if IsBlockedIP(ip) {
+				t.Errorf("IsBlockedIP(%q) = true, want false", tc.ip)
+			}
+		})
+	}
+}
+
+func TestIsBlockedIPv6MappedIPv4(t *testing.T) {
+	// ::ffff:192.168.1.1 is an IPv6-mapped IPv4 address — should be blocked as RFC1918.
+	// Construct it manually as a 16-byte IP.
+	mapped := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 192, 168, 1, 1}
+	if !IsBlockedIP(mapped) {
+		t.Errorf("IsBlockedIP(::ffff:192.168.1.1) = false, want true (IPv6-mapped IPv4 must be normalized)")
+	}
+
+	// ::ffff:8.8.8.8 — IPv6-mapped public IP — should be allowed.
+	mappedPublic := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 8, 8, 8, 8}
+	if IsBlockedIP(mappedPublic) {
+		t.Errorf("IsBlockedIP(::ffff:8.8.8.8) = true, want false")
+	}
+}
+
+func TestIsBlockedIPEdgeCases(t *testing.T) {
+	// The boundary between RFC1918 and public ranges.
+	// 172.15.255.255 is NOT private (just below 172.16.0.0/12).
+	notPrivate := net.ParseIP("172.15.255.255")
+	if IsBlockedIP(notPrivate) {
+		t.Errorf("IsBlockedIP(172.15.255.255) = true, want false (outside 172.16.0.0/12)")
+	}
+	// 172.32.0.0 is NOT private (just above 172.31.255.255).
+	notPrivate2 := net.ParseIP("172.32.0.0")
+	if IsBlockedIP(notPrivate2) {
+		t.Errorf("IsBlockedIP(172.32.0.0) = true, want false (outside 172.16.0.0/12)")
+	}
+	// CGN: 100.63.255.255 is NOT in 100.64.0.0/10.
+	notCGN := net.ParseIP("100.63.255.255")
+	if IsBlockedIP(notCGN) {
+		t.Errorf("IsBlockedIP(100.63.255.255) = true, want false (outside 100.64.0.0/10)")
+	}
+	// CGN: 100.128.0.0 is NOT in 100.64.0.0/10.
+	notCGN2 := net.ParseIP("100.128.0.0")
+	if IsBlockedIP(notCGN2) {
+		t.Errorf("IsBlockedIP(100.128.0.0) = true, want false (outside 100.64.0.0/10)")
+	}
+}
+
+// TestBlockedCIDRsValid verifies that all entries in blockedCIDRStrings parse
+// successfully. This catches programming errors in the CIDR list without
+// requiring a startup panic. The init() function records parse failures in
+// blockedCIDRParseErrors rather than panicking; this test makes those failures
+// visible as test failures during CI.
+func TestBlockedCIDRsValid(t *testing.T) {
+	for _, msg := range BlockedCIDRParseErrors() {
+		t.Errorf("CIDR parse error: %s", msg)
+	}
+}