From 493a06d0e7207a1e34fdc746502c74632152cf91 Mon Sep 17 00:00:00 2001
From: v-byte-cpu <65545655+v-byte-cpu@users.noreply.github.com>
Date: Thu, 11 Jun 2026 19:56:02 +0400
Subject: [PATCH] ci: gate go jobs on relevant paths and document ENOBUFS

Add a paths-filter-based gate to skip Go CI jobs on irrelevant changes,
while still running them for Go, module, lint, and CI/script updates.

Document the `send: No buffer space available` failure mode in the TCP scan
README section and recommend `--rate` as the primary fix.
---
 .github/workflows/ci.yml | 23 +++++++++++++++++++++++
 README.md                |  4 ++++
 2 files changed, 27 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a12f9e9..dd7be67 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,28 @@ permissions:
   contents: read
 
 jobs:
+  changes:
+    runs-on: ubuntu-latest
+    outputs:
+      go_ci: ${{ steps.filter.outputs.go_ci }}
+
+    steps:
+      - name: Detect changed paths
+        id: filter
+        uses: dorny/paths-filter@v4
+        with:
+          filters: |
+            go_ci:
+              - '**/*.go'
+              - 'go.mod'
+              - 'go.sum'
+              - '.golangci.yml'
+              - '.github/workflows/**'
+              - '.github/scripts/**'
+
   go:
+    needs: changes
+    if: needs.changes.outputs.go_ci == 'true'
     runs-on: ubuntu-latest
     container: golang:1.25-alpine
     env:
@@ -61,6 +82,8 @@ jobs:
         run: go build -ldflags "-w -s"
 
   go-macos:
+    needs: changes
+    if: needs.changes.outputs.go_ci == 'true'
     name: go (macOS ${{ matrix.goarch }})
     runs-on: ${{ matrix.runner }}
     env:
diff --git a/README.md b/README.md
index ecd3612..85971fe 100644
--- a/README.md
+++ b/README.md
@@ -140,6 +140,10 @@ sample output:
 
 In this case we find out that ports 22 and 443 are open.
 
+If you see `send: No buffer space available` during large scans, it usually means the sender is outrunning the kernel/raw-socket buffers.
+The first fix is to add `--rate` and lower the send burst, for example `-r 100000/s` or lower if needed.
+On some systems, tuning OS socket/buffer limits can also help, but rate limiting is the primary fix.
+
 scan with JSON output:
 
 ```