Merge pull request #1 from HENNGE/initial-iteration

feat: Initial Implementation of SPF2IP-Go Resolver

Author: yongjiajun

.github/workflows/test_and_lint.yml

@@ -0,0 +1,44 @@
+name: Test and Lint
+
+on:
+  push:
+
+permissions:
+  contents: read
+
+env:
+  GO_VERSION: 1.24.2
+  GOLANGCI_LINT_VERSION: v2.1.6
+
+jobs:
+  golangci-lint:
+    name: golangci-lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@4afd733a84b1f43292c63897423277bb7f4313a9 # v8
+        with:
+          version: ${{ env.GOLANGCI_LINT_VERSION }}
+
+  go-test:
+    name: Go test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      - name: Go test
+        run: go test -v ./...

.gitignore

@@ -0,0 +1,5 @@
+# Binary
+/spf2ip-go
+
+# OS generated files
+.DS_Store

README.md

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+# SPF2IP-Go
+
+A Go implementation designed to resolve a domain's SPF (Sender Policy Framework) records into a list of IP addresses and CIDR blocks. This project is a remake of and inspired by the original Python-based [SPF2IP by Nathan Dines](https://github.com/nathandines/SPF2IP).
+
+This tool recursively processes SPF records, handling `include` and `redirect` mechanisms, and extracts all authorized IP networks.
+
+## Features
+
+- Resolves SPF records for a given domain.
+- Supports both IPv4 and IPv6 resolution (`ip4`, `ip6`, `a`, `mx` mechanisms).
+- Handles `include` and `redirect` mechanisms recursively.
+- Implements strict redirect logic (a `redirect` overrides preceding mechanisms in the same record).
+- Detects and prevents resolution loops and excessive lookups (via include depth limit).
+- Outputs all IPs and networks in canonical CIDR notation (e.g., `1.2.3.4/32`, `10.0.0.0/24`), sorted and unique.
+
+## Acknowledgements
+
+This project is a Go remake of the original [SPF2IP (Python) by Nathan Dines](https://github.com/nathandines/SPF2IP). Full credit and thanks to Nathan Dines for the original concept and implementation.
+
+## Installation
+
+### Building from Source
+To build the `spf2ip-go` executable from source, follow these steps:
+
+1.  Clone the repository:
+    ```bash
+    git clone https://github.com/HENNGE/spf2ip-go.git
+    cd spf2ip-go
+    ```
+    
+2.  Build the executable:
+    ```bash
+    go build github.com/HENNGE/spf2ip-go/cmd/spf2ip-go
+    ```
+    This will create an executable named `spf2ip-go` in the current directory.
+
+### Using Go Modules
+If you prefer to use Go modules, you can run the following command to install the package:
+
+```bash
+go install github.com/HENNGE/spf2ip-go/cmd/spf2ip-go@latest
+```
+
+## CLI Usage
+
+```bash
+spf2ip-go --domain <domain_name> [--ip-version <4|6>] [--debug]
+```
+
+### Flags
+
+* `--domain <string>`: (Required) The domain for which the SPF records should be resolved.
+* `--ip-version <int>`: (Optional) The IP version to extract. Accepts `4` for IPv4 or `6` for IPv6. Defaults to `4`.
+* `--debug`: (Optional) Enable debug logging output to stderr. Defaults to `false`.
+
+### Examples
+
+1.  **Get IPv4 addresses for `example.com`:**
+    ```bash
+    spf2ip-go --domain example.com
+    ```
+
+1.  **Get IPv6 addresses for `example.com`:**
+    ```bash
+    spf2ip-go --domain example.com --ip-version 6
+    ```
+
+1.  **Get IPv4 addresses for `example.com` with debug output:**
+    ```bash
+    spf2ip-go --domain example.com --debug
+    ```

cidr_sorter.go

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+package spf2ip
+
+import (
+	"bytes"
+	"net"
+)
+
+type cidrSorter []string
+
+func (s cidrSorter) Len() int      { return len(s) }
+func (s cidrSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+func (s cidrSorter) Less(i, j int) bool {
+	ip1, p1, isV4_1 := parseCIDR(s[i])
+	ip2, p2, isV4_2 := parseCIDR(s[j])
+
+	isValid1 := ip1 != nil
+	isValid2 := ip2 != nil
+
+	if !isValid1 && !isValid2 {
+		return s[i] < s[j]
+	} // Both invalid, sort by string
+
+	if !isValid1 {
+		return false
+	} // Invalid sorts after valid
+
+	if !isValid2 {
+		return true
+	} // Valid sorts before invalid
+
+	// Both are valid CIDRs
+	if isV4_1 != isV4_2 {
+		return isV4_1 // IPv4 comes before IPv6
+	}
+
+	if cmp := bytes.Compare(ip1, ip2); cmp != 0 {
+		return cmp < 0
+	}
+
+	return p1 < p2 // Smaller prefix (wider network) comes first
+}
+
+// parseCIDR parses a CIDR notation string and returns the IP, prefix length, and whether it's IPv4.
+func parseCIDR(s string) (ip net.IP, prefix int, isV4 bool) {
+	_, ipNet, err := net.ParseCIDR(s)
+	if err != nil {
+		return nil, 0, false
+	}
+
+	ip = ipNet.IP
+	prefix, _ = ipNet.Mask.Size()
+
+	if ip4 := ip.To4(); ip4 != nil {
+		return ip4, prefix, true
+	}
+
+	return ip, prefix, false
+}

cidr_sorter_test.go

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+package spf2ip
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCIDRSorter(t *testing.T) {
+	t.Parallel()
+
+	for description, tc := range map[string]struct {
+		cidrs    []string
+		expected []string
+	}{
+		"empty": {
+			cidrs:    []string{},
+			expected: []string{},
+		},
+		"IPv4": {
+			cidrs:    []string{"5.6.7.8/32", "1.1.1.0/24", "1.2.3.4/32"},
+			expected: []string{"1.1.1.0/24", "1.2.3.4/32", "5.6.7.8/32"},
+		},
+		"IPv6": {
+			cidrs:    []string{"2001:db8:abcd::/48", "2001:db8::/32", "2001:db8:1234::/64"},
+			expected: []string{"2001:db8::/32", "2001:db8:1234::/64", "2001:db8:abcd::/48"},
+		},
+		"mixed": {
+			cidrs:    []string{"2001:db8::/32", "1.1.1.0/24", "4.5.6.7/32", "2001:db8:abcd::/48"},
+			expected: []string{"1.1.1.0/24", "4.5.6.7/32", "2001:db8::/32", "2001:db8:abcd::/48"},
+		},
+		"invalid": {
+			cidrs:    []string{"invalid", "", "1.2.3.4/32"},
+			expected: []string{"1.2.3.4/32", "", "invalid"},
+		},
+	} {
+		t.Run(description, func(t *testing.T) {
+			t.Parallel()
+
+			// Create a copy of the CIDRs to avoid modifying the original slice.
+			cidrs := make([]string, len(tc.cidrs))
+			copy(cidrs, tc.cidrs)
+
+			sort.Sort(cidrSorter(cidrs))
+
+			assert.Equal(t, tc.expected, cidrs, "Sorted CIDRs should match expected order")
+		})
+	}
+}

cmd/spf2ip-go/main.go

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+package main
+
+import (
+	context "context"
+	"flag"
+	"fmt"
+	"log"
+	net "net"
+	"os"
+
+	spf2ip "github.com/HENNGE/spf2ip-go"
+)
+
+func main() {
+	domain := flag.String("domain", "", "Domain for which the IP addresses should be extracted (required)")
+	ipVersion := flag.Int("ip-version", 4, "Define version of IP list to extract (4 or 6; default is 4)")
+	debugLogging := flag.Bool("debug", false, "Enable debug logging output to stderr")
+
+	flag.Parse()
+
+	if *domain == "" {
+		log.Printf("Usage of spf2ip-go:")
+		flag.PrintDefaults()
+		os.Exit(1)
+	}
+
+	if *ipVersion != 4 && *ipVersion != 6 {
+		log.Fatal("Error: --ip-version must be '4' or '6'")
+	}
+
+	resolver := spf2ip.NewSPF2IPResolver(net.DefaultResolver, *debugLogging)
+
+	ips, err := resolver.Resolve(context.Background(), *domain, *ipVersion)
+	if err != nil {
+		log.Fatalf("Error resolving SPF: %v", err)
+	}
+
+	log.Printf("Resolved %d IPs for domain %s:\n", len(ips), *domain)
+
+	for _, ip := range ips {
+		fmt.Println(ip)
+	}
+}

go.mod

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+module github.com/HENNGE/spf2ip-go
+
+go 1.24.2
+
+require (
+	github.com/stretchr/testify v1.10.0
+	go.uber.org/mock v0.5.2
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,12 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.uber.org/mock v0.5.2 h1:LbtPTcP8A5k9WPXj54PPPbjcI4Y6lhyOZXn+VS7wNko=
+go.uber.org/mock v0.5.2/go.mod h1:wLlUxC2vVTPTaE3UD51E0BGOAElKrILxhVSDYQLld5o=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=