diff --git a/pkg/rings/cidr.go b/pkg/rings/cidr.go new file mode 100644 index 0000000..daa6939 --- /dev/null +++ b/pkg/rings/cidr.go @@ -0,0 +1,43 @@ +package rings + +import "net/netip" + +// AddrFromU32 converts a 32bit value into an IPv4 +// address. +func AddrFromU32(v uint32) netip.Addr { + return AddrFrom4( + uint(v>>24), + uint(v>>16), + uint(v>>8), + uint(v), + ) +} + +// AddrFrom4 assembles an IPv4 address for 4 numbers. +// each number is truncated to 8-bits. +func AddrFrom4(a, b, c, d uint) netip.Addr { + return netip.AddrFrom4([4]byte{ + byte(a & 0xff), + byte(b & 0xff), + byte(c & 0xff), + byte(d & 0xff), + }) +} + +// AddrToU32 converts a valid IPv4 address into it's +// 32bit numeric representation. +func AddrToU32(addr netip.Addr) (v uint32, ok bool) { + if addr.IsValid() { + if addr.Is4() || addr.Is4In6() { + a4 := addr.As4() + + v = uint32(a4[0])<<24 + + uint32(a4[1])<<16 + + uint32(a4[2])<<8 + + uint32(a4[3]) + return v, true + } + } + + return 0, false +} diff --git a/pkg/rings/cidr_test.go b/pkg/rings/cidr_test.go new file mode 100644 index 0000000..1ac0df6 --- /dev/null +++ b/pkg/rings/cidr_test.go @@ -0,0 +1,92 @@ +package rings + +import ( + "fmt" + "net/netip" + "testing" +) + +func TestAddrFrom4(t *testing.T) { + cases := []struct { + v [4]uint + s string + }{ + {[4]uint{0, 0, 0, 0}, "0.0.0.0"}, + {[4]uint{127, 0, 0, 1}, "127.0.0.1"}, + {[4]uint{4096 + 127, 0, 0, 1}, "127.0.0.1"}, + {[4]uint{257, 258, 259, 260}, "1.2.3.4"}, + {[4]uint{255, 255, 255, 255}, "255.255.255.255"}, + } + + for i, tc := range cases { + fn := fmt.Sprintf("%v.%v.%v.%v", tc.v[0], tc.v[1], tc.v[2], tc.v[3]) + addr := AddrFrom4(tc.v[0], tc.v[1], tc.v[2], tc.v[3]) + s := addr.String() + + if s == tc.s { + t.Logf("[%v/%v]: %s → %s", i, len(cases), fn, s) + } else { + t.Errorf("ERROR: [%v/%v]: %s → %s (expected %s)", i, len(cases), fn, s, tc.s) + } + } +} + +func TestAddrU32Invalid(t *testing.T) { + cases := []netip.Addr{ + {}, + netip.IPv6Unspecified(), + netip.IPv6Loopback(), + } + + for i, tc := range cases { + v, ok := AddrToU32(tc) + switch { + case !ok && v == 0: + t.Logf("[%v/%v]: %s → %v %v", i, len(cases), tc, 0, false) + default: + t.Errorf("ERROR: [%v/%v]: %s → %v %v (expected %v %v)", i, len(cases), + tc, v, ok, 0, false) + } + } +} + +func TestAddrU32Valid(t *testing.T) { + cases := []netip.Addr{ + netip.IPv4Unspecified(), + AddrFrom4(0, 0, 0, 0), + AddrFrom4(1, 2, 3, 4), + AddrFrom4(10, 20, 30, 40), + AddrFrom4(127, 0, 0, 1), + AddrFrom4(255, 255, 255, 255), + MustParseAddr("::ffff:1.2.3.4"), + } + + for i, tc := range cases { + u32, ok := AddrToU32(tc) + if !ok { + t.Errorf("ERROR: [%v/%v]: %s → %v %v", i, len(cases), tc, u32, ok) + continue + } + + addr := AddrFromU32(u32) + if tc.Is4In6() { + ok = addr.Compare(tc.Unmap()) == 0 + } else { + ok = addr.Compare(tc) == 0 + } + + if ok { + t.Logf("[%v/%v]: %s → %v → %s", i, len(cases), tc, u32, addr) + } else { + t.Errorf("ERROR: [%v/%v]: %s → %v → %s", i, len(cases), tc, u32, addr) + } + } +} + +func MustParseAddr(s string) netip.Addr { + addr, err := netip.ParseAddr(s) + if err != nil { + panic(err) + } + return addr +}