🐛 Support range decision on stream mode

pkg/ip/cidr.go

@@ -0,0 +1,48 @@
+package ip
+
+import (
+	"net"
+	"strconv"
+	"strings"
+)
+
+// CIDRKeys returns all possible CIDR prefixes of an IP, from the most specific (/32 for IPv4, /128 for IPv6) to the least specific (/0).
+func CIDRKeys(ipStr string) []string {
+	ip := net.ParseIP(ipStr)
+	if ip == nil {
+		return nil
+	}
+	ip4 := ip.To4()
+	if ip4 != nil {
+		keys := make([]string, 0, 33)
+		for bits := 32; bits >= 0; bits-- {
+			mask := net.CIDRMask(bits, 32)
+			n := make(net.IP, 4)
+			for i := 0; i < 4; i++ {
+				n[i] = ip4[i] & mask[i]
+			}
+			keys = append(keys, n.String()+"/"+strconv.Itoa(bits))
+		}
+		return keys
+	}
+	ip16 := ip.To16()
+	keys := make([]string, 0, 129)
+	for bits := 128; bits >= 0; bits-- {
+		mask := net.CIDRMask(bits, 128)
+		n := make(net.IP, 16)
+		for i := 0; i < 16; i++ {
+			n[i] = ip16[i] & mask[i]
+		}
+		keys = append(keys, n.String()+"/"+strconv.Itoa(bits))
+	}
+	return keys
+}
+
+// NormalizeCIDR parses a CIDR string and returns its normalized form, or an empty string if invalid.
+func NormalizeCIDR(cidrStr string) string {
+	_, ipNet, err := net.ParseCIDR(strings.TrimSpace(cidrStr))
+	if err != nil {
+		return ""
+	}
+	return ipNet.String()
+}

pkg/ip/cidr_test.go

@@ -0,0 +1,126 @@
+package ip
+
+import (
+	"strconv"
+	"strings"
+	"testing"
+)
+
+func TestCIDRKeys(t *testing.T) {
+	tests := []struct {
+		ip       string
+		wantKeys int
+		checks   map[int]string
+	}{
+		{
+			ip:       "10.0.0.1",
+			wantKeys: 33,
+			checks:   map[int]string{0: "10.0.0.1/32", 8: "10.0.0.0/24", 32: "0.0.0.0/0"},
+		},
+		{
+			ip:       "2001:db8::1",
+			wantKeys: 129,
+			checks:   map[int]string{0: "2001:db8::1/128", 32: "2001:db8::/96", 128: "::/0"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.ip, func(t *testing.T) {
+			keys := CIDRKeys(tt.ip)
+			if keys == nil {
+				t.Fatal("CIDRKeys returned nil")
+			}
+			if len(keys) != tt.wantKeys {
+				t.Fatalf("expected %d keys, got %d", tt.wantKeys, len(keys))
+			}
+			for idx, want := range tt.checks {
+				if keys[idx] != want {
+					t.Errorf("keys[%d] should be %s, got %s", idx, want, keys[idx])
+				}
+			}
+		})
+	}
+}
+
+func TestCIDRKeys_MostToLeastSpecific(t *testing.T) {
+	ips := []string{"10.0.0.1", "2001:db8::1"}
+	for _, ip := range ips {
+		t.Run(ip, func(t *testing.T) {
+			keys := CIDRKeys(ip)
+			for i := 1; i < len(keys); i++ {
+				prevBits := strings.Split(keys[i-1], "/")[1]
+				curBits := strings.Split(keys[i], "/")[1]
+				prevN, _ := strconv.Atoi(prevBits)
+				curN, _ := strconv.Atoi(curBits)
+				if prevN <= curN {
+					t.Errorf("keys should go from most specific to least specific at index %d: /%d <= /%d", i, prevN, curN)
+				}
+			}
+		})
+	}
+}
+
+func TestCIDRKeys_IPVariants(t *testing.T) {
+	tests := []struct {
+		ip       string
+		wantKeys int
+	}{
+		{"0.0.0.0", 33},
+		{"255.255.255.255", 33},
+		{"1.2.3.4", 33},
+		{"10.0.0.1", 33},
+		{"192.168.1.1", 33},
+		{"invalid", 0},
+		{"", 0},
+		{"   ", 0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.ip, func(t *testing.T) {
+			keys := CIDRKeys(tt.ip)
+			if len(keys) != tt.wantKeys {
+				t.Errorf("CIDRKeys(%q) returned %d keys, want %d", tt.ip, len(keys), tt.wantKeys)
+			}
+		})
+	}
+}
+
+func TestCIDRKeys_VerifyNetworkAddress(t *testing.T) {
+	keys := CIDRKeys("10.1.2.3")
+	tests := []struct {
+		bits int
+		want string
+	}{
+		{24, "10.1.2.0/24"},
+		{16, "10.1.0.0/16"},
+		{8, "10.0.0.0/8"},
+	}
+	for _, tt := range tests {
+		if got := keys[32-tt.bits]; got != tt.want {
+			t.Errorf("/%d network should be %s, got %s", tt.bits, tt.want, got)
+		}
+	}
+}
+
+func TestNormalizeCIDR(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"10.0.0.0/8", "10.0.0.0/8"},
+		{"10.0.0.0/16", "10.0.0.0/16"},
+		{"192.168.1.0/24", "192.168.1.0/24"},
+		{"2001:db8::/32", "2001:db8::/32"},
+		{"0.0.0.0/0", "0.0.0.0/0"},
+		{"::/0", "::/0"},
+		{"invalid", ""},
+		{"", ""},
+		{"  10.0.0.0/8  ", "10.0.0.0/8"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := NormalizeCIDR(tt.input)
+			if got != tt.want {
+				t.Errorf("NormalizeCIDR(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}