IsIPv4/v6 util

Author: sadfun

ips.go

@@ -0,0 +1,145 @@
+package utils
+
+import "net"
+
+// IsIPv4 is plagiarism of net.ParseIP,
+// but without check for IPv6 case and without returning net.IP slice, whereby IsIPv4 makes no allocations.
+func IsIPv4(s string) bool {
+	for i := 0; i < net.IPv4len; i++ {
+		if len(s) == 0 {
+			return false
+		}
+
+		if i > 0 {
+			if s[0] != '.' {
+				return false
+			}
+			s = s[1:]
+		}
+
+		n, ci := 0, 0
+
+		for ci = 0; ci < len(s) && '0' <= s[ci] && s[ci] <= '9'; ci++ {
+			n = n*10 + int(s[ci]-'0')
+			if n >= 0xFF {
+				return false
+			}
+		}
+
+		if ci == 0 || n > 0xFF || (ci > 1 && s[0] == '0') {
+			return false
+		}
+
+		s = s[ci:]
+	}
+
+	if len(s) != 0 {
+		return false
+	}
+
+	return true
+}
+
+// IsIPv6 is plagiarism of net.ParseIP,
+// but without check for IPv4 case and without returning net.IP slice, whereby IsIPv6 makes no allocations.
+func IsIPv6(s string) bool {
+	ellipsis := -1 // position of ellipsis in ip
+
+	// Might have leading ellipsis
+	if len(s) >= 2 && s[0] == ':' && s[1] == ':' {
+		ellipsis = 0
+		s = s[2:]
+		// Might be only ellipsis
+		if len(s) == 0 {
+			return true
+		}
+	}
+
+	// Loop, parsing hex numbers followed by colon.
+	i := 0
+	for i < net.IPv6len {
+		// Hex number.
+		n, ci := 0, 0
+
+		for ci = 0; ci < len(s); ci++ {
+			if '0' <= s[ci] && s[ci] <= '9' {
+				n *= 16
+				n += int(s[ci] - '0')
+			} else if 'a' <= s[ci] && s[ci] <= 'f' {
+				n *= 16
+				n += int(s[ci]-'a') + 10
+			} else if 'A' <= s[ci] && s[ci] <= 'F' {
+				n *= 16
+				n += int(s[ci]-'A') + 10
+			} else {
+				break
+			}
+			if n > 0xFFFF {
+				return false
+			}
+		}
+		if ci == 0 || n > 0xFFFF {
+			return false
+		}
+
+		if ci < len(s) && s[ci] == '.' {
+			if ellipsis < 0 && i != net.IPv6len-net.IPv4len {
+				return false
+			}
+			if i+net.IPv4len > net.IPv6len {
+				return false
+			}
+
+			if !IsIPv4(s) {
+				return false
+			}
+
+			s = ""
+			i += net.IPv4len
+			break
+		}
+
+		// Save this 16-bit chunk.
+		i += 2
+
+		// Stop at end of string.
+		s = s[ci:]
+		if len(s) == 0 {
+			break
+		}
+
+		// Otherwise must be followed by colon and more.
+		if s[0] != ':' || len(s) == 1 {
+			return false
+		}
+		s = s[1:]
+
+		// Look for ellipsis.
+		if s[0] == ':' {
+			if ellipsis >= 0 { // already have one
+				return false
+			}
+			ellipsis = i
+			s = s[1:]
+			if len(s) == 0 { // can be at end
+				break
+			}
+		}
+	}
+
+	// Must have used entire string.
+	if len(s) != 0 {
+		return false
+	}
+
+	// If didn't parse enough, expand ellipsis.
+	if i < net.IPv6len {
+		if ellipsis < 0 {
+			return false
+		}
+	} else if ellipsis >= 0 {
+		// Ellipsis must represent at least one 0 group.
+		return false
+	}
+	return true
+}

ips_test.go

@@ -0,0 +1,87 @@
+// ⚡️ Fiber is an Express inspired web framework written in Go with ☕️
+// 🤖 Github Repository: https://github.com/gofiber/fiber
+// 📌 API Documentation: https://docs.gofiber.io
+
+package utils
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_IsIPv4(t *testing.T) {
+	t.Parallel()
+
+	require.Equal(t, true, IsIPv4("174.23.33.100"))
+	require.Equal(t, true, IsIPv4("127.0.0.1"))
+	require.Equal(t, true, IsIPv4("0.0.0.0"))
+
+	require.Equal(t, false, IsIPv4(".0.0.0"))
+	require.Equal(t, false, IsIPv4("0.0.0."))
+	require.Equal(t, false, IsIPv4("0.0.0"))
+	require.Equal(t, false, IsIPv4(".0.0.0."))
+	require.Equal(t, false, IsIPv4("0.0.0.0.0"))
+	require.Equal(t, false, IsIPv4("0"))
+	require.Equal(t, false, IsIPv4(""))
+	require.Equal(t, false, IsIPv4("2345:0425:2CA1::0567:5673:23b5"))
+	require.Equal(t, false, IsIPv4("invalid"))
+}
+
+// go test -v -run=^$ -bench=UnsafeString -benchmem -count=2
+
+func Benchmark_IsIPv4(b *testing.B) {
+	ip := "174.23.33.100"
+	var res bool
+
+	b.Run("fiber", func(b *testing.B) {
+		for n := 0; n < b.N; n++ {
+			res = IsIPv4(ip)
+		}
+		require.Equal(b, true, res)
+	})
+
+	b.Run("default", func(b *testing.B) {
+		for n := 0; n < b.N; n++ {
+			res = net.ParseIP(ip) != nil
+		}
+		require.Equal(b, true, res)
+	})
+}
+
+func Test_IsIPv6(t *testing.T) {
+	t.Parallel()
+
+	require.Equal(t, true, IsIPv6("9396:9549:b4f7:8ed0:4791:1330:8c06:e62d"))
+	require.Equal(t, true, IsIPv6("2345:0425:2CA1::0567:5673:23b5"))
+	require.Equal(t, true, IsIPv6("2001:1:2:3:4:5:6:7"))
+
+	require.Equal(t, false, IsIPv6("1.1.1.1"))
+	require.Equal(t, false, IsIPv6("2001:1:2:3:4:5:6:"))
+	require.Equal(t, false, IsIPv6(":1:2:3:4:5:6:"))
+	require.Equal(t, false, IsIPv6("1:2:3:4:5:6:"))
+	require.Equal(t, false, IsIPv6(""))
+	require.Equal(t, false, IsIPv6("invalid"))
+}
+
+// go test -v -run=^$ -bench=UnsafeString -benchmem -count=2
+
+func Benchmark_IsIPv6(b *testing.B) {
+	ip := "9396:9549:b4f7:8ed0:4791:1330:8c06:e62d"
+	var res bool
+
+	b.Run("fiber", func(b *testing.B) {
+		for n := 0; n < b.N; n++ {
+			res = IsIPv6(ip)
+		}
+		require.Equal(b, true, res)
+	})
+
+	b.Run("default", func(b *testing.B) {
+		for n := 0; n < b.N; n++ {
+			res = net.ParseIP(ip) != nil
+		}
+		require.Equal(b, true, res)
+	})
+}