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net: ParseCIDR returns IPNet instead of IPMask

Note that this CL will break your existing code which uses
ParseCIDR.

This CL changes ParseCIDR("172.16.253.121/28") to return
the IP address "172.16.253.121", the network implied by the
network number "172.16.253.112" and mask "255.255.255.240".

R=rsc, borman
CC=golang-dev
https://golang.org/cl/4749043
This commit is contained in:
Mikio Hara 2011-09-07 14:01:12 -04:00 committed by Russ Cox
parent 4ba677c6ea
commit a2c2c87439
2 changed files with 248 additions and 63 deletions

View File

@ -22,10 +22,7 @@ const (
// An IP is a single IP address, an array of bytes. // An IP is a single IP address, an array of bytes.
// Functions in this package accept either 4-byte (IPv4) // Functions in this package accept either 4-byte (IPv4)
// or 16-byte (IPv6) arrays as input. Unless otherwise // or 16-byte (IPv6) arrays as input.
// specified, functions in this package always return
// IP addresses in 16-byte form using the canonical
// embedding.
// //
// Note that in this documentation, referring to an // Note that in this documentation, referring to an
// IP address as an IPv4 address or an IPv6 address // IP address as an IPv4 address or an IPv6 address
@ -37,6 +34,12 @@ type IP []byte
// An IP mask is an IP address. // An IP mask is an IP address.
type IPMask []byte type IPMask []byte
// An IPNet represents an IP network.
type IPNet struct {
IP IP // network number
Mask IPMask // network mask
}
// IPv4 returns the IP address (in 16-byte form) of the // IPv4 returns the IP address (in 16-byte form) of the
// IPv4 address a.b.c.d. // IPv4 address a.b.c.d.
func IPv4(a, b, c, d byte) IP { func IPv4(a, b, c, d byte) IP {
@ -62,6 +65,30 @@ func IPv4Mask(a, b, c, d byte) IPMask {
return p return p
} }
// CIDRMask returns an IPMask of size bits with the first n bits
// set to to 1. nil is returned if the mask is impossible.
func CIDRMask(ones, bits int) IPMask {
if bits != 8*IPv4len && bits != 8*IPv6len {
return nil
}
if ones < 0 || ones > bits {
return nil
}
l := bits / 8
m := make(IPMask, l)
n := uint(ones)
for i := 0; i < l; i++ {
if n >= 8 {
m[i] = 0xff
n -= 8
continue
}
m[i] = ^byte(0xff >> n)
n = 0
}
return m
}
// Well-known IPv4 addresses // Well-known IPv4 addresses
var ( var (
IPv4bcast = IPv4(255, 255, 255, 255) // broadcast IPv4bcast = IPv4(255, 255, 255, 255) // broadcast
@ -365,6 +392,65 @@ func (m IPMask) String() string {
return s return s
} }
func networkNumberAndMask(n *IPNet) (ip IP, m IPMask) {
if ip = n.IP.To4(); ip == nil {
ip = n.IP
if len(ip) != IPv6len {
return nil, nil
}
}
m = n.Mask
switch len(m) {
case IPv4len:
if len(ip) != IPv4len {
return nil, nil
}
case IPv6len:
if len(ip) == IPv4len {
m = m[12:]
}
default:
return nil, nil
}
return
}
// Contains reports whether the network includes ip.
func (n *IPNet) Contains(ip IP) bool {
nn, m := networkNumberAndMask(n)
if x := ip.To4(); x != nil {
ip = x
}
l := len(ip)
if l != len(nn) {
return false
}
for i := 0; i < l; i++ {
if nn[i]&m[i] != ip[i]&m[i] {
return false
}
}
return true
}
// String returns the CIDR notation of n like "192.168.100.1/24"
// or "2001:DB8::/48" as defined in RFC 4632 and RFC 4291.
// If the mask is not in the canonical form, it returns the
// string which consists of an IP address, followed by a slash
// character and a mask expressed as hexadecimal form with no
// punctuation like "192.168.100.1/c000ff00".
func (n *IPNet) String() string {
nn, m := networkNumberAndMask(n)
if nn == nil || m == nil {
return "<nil>"
}
l := simpleMaskLength(m)
if l == -1 {
return nn.String() + "/" + m.String()
}
return nn.String() + "/" + itod(uint(l))
}
// Parse IPv4 address (d.d.d.d). // Parse IPv4 address (d.d.d.d).
func parseIPv4(s string) IP { func parseIPv4(s string) IP {
var p [IPv4len]byte var p [IPv4len]byte
@ -536,48 +622,26 @@ func ParseIP(s string) IP {
// ParseCIDR parses s as a CIDR notation IP address and mask, // ParseCIDR parses s as a CIDR notation IP address and mask,
// like "192.168.100.1/24" or "2001:DB8::/48", as defined in // like "192.168.100.1/24" or "2001:DB8::/48", as defined in
// RFC 4632 and RFC 4291. // RFC 4632 and RFC 4291.
func ParseCIDR(s string) (ip IP, mask IPMask, err os.Error) { //
// It returns the IP address and the network implied by the IP
// and mask. For example, ParseCIDR("192.168.100.1/16") returns
// the IP address 192.168.100.1 and the network 192.168.0.0/16.
func ParseCIDR(s string) (IP, *IPNet, os.Error) {
i := byteIndex(s, '/') i := byteIndex(s, '/')
if i < 0 { if i < 0 {
return nil, nil, &ParseError{"CIDR address", s} return nil, nil, &ParseError{"CIDR address", s}
} }
ipstr, maskstr := s[:i], s[i+1:] ipstr, maskstr := s[:i], s[i+1:]
iplen := IPv4len iplen := IPv4len
ip = parseIPv4(ipstr) ip := parseIPv4(ipstr)
if ip == nil { if ip == nil {
iplen = IPv6len iplen = IPv6len
ip = parseIPv6(ipstr) ip = parseIPv6(ipstr)
} }
nn, i, ok := dtoi(maskstr, 0) n, i, ok := dtoi(maskstr, 0)
if ip == nil || !ok || i != len(maskstr) || nn < 0 || nn > 8*iplen { if ip == nil || !ok || i != len(maskstr) || n < 0 || n > 8*iplen {
return nil, nil, &ParseError{"CIDR address", s} return nil, nil, &ParseError{"CIDR address", s}
} }
n := uint(nn) m := CIDRMask(n, 8*iplen)
if iplen == IPv4len { return ip, &IPNet{ip.Mask(m), m}, nil
v4mask := ^uint32(0xffffffff >> n)
mask = IPv4Mask(byte(v4mask>>24), byte(v4mask>>16), byte(v4mask>>8), byte(v4mask))
} else {
mask = make(IPMask, IPv6len)
for i := 0; i < IPv6len; i++ {
if n >= 8 {
mask[i] = 0xff
n -= 8
continue
}
mask[i] = ^byte(0xff >> n)
n = 0
}
}
// address must not have any bits not in mask
mip := ip
if iplen == IPv4len {
mip = ip[12:]
}
for i := range mip {
if mip[i]&^mask[i] != 0 {
return nil, nil, &ParseError{"CIDR address", s}
}
}
return ip, mask, nil
} }

View File

@ -34,12 +34,13 @@ var parseiptests = []struct {
{"::ffff:127.0.0.1", IPv4(127, 0, 0, 1)}, {"::ffff:127.0.0.1", IPv4(127, 0, 0, 1)},
{"2001:4860:0:2001::68", IP{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68}}, {"2001:4860:0:2001::68", IP{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68}},
{"::ffff:4a7d:1363", IPv4(74, 125, 19, 99)}, {"::ffff:4a7d:1363", IPv4(74, 125, 19, 99)},
{"", nil},
} }
func TestParseIP(t *testing.T) { func TestParseIP(t *testing.T) {
for _, tt := range parseiptests { for _, tt := range parseiptests {
if out := ParseIP(tt.in); !isEqual(out, tt.out) { if out := ParseIP(tt.in); !isEqual(out, tt.out) {
t.Errorf("ParseIP(%#q) = %v, want %v", tt.in, out, tt.out) t.Errorf("ParseIP(%q) = %v, want %v", tt.in, out, tt.out)
} }
} }
} }
@ -63,7 +64,7 @@ var ipstringtests = []struct {
func TestIPString(t *testing.T) { func TestIPString(t *testing.T) {
for _, tt := range ipstringtests { for _, tt := range ipstringtests {
if out := tt.in.String(); out != tt.out { if out := tt.in.String(); out != tt.out {
t.Errorf("IP.String(%v) = %#q, want %#q", tt.in, out, tt.out) t.Errorf("IP.String(%v) = %q, want %q", tt.in, out, tt.out)
} }
} }
} }
@ -109,33 +110,153 @@ func TestIPMaskString(t *testing.T) {
} }
var parsecidrtests = []struct { var parsecidrtests = []struct {
in string in string
ip IP ip IP
mask IPMask net *IPNet
err os.Error err os.Error
}{ }{
{"135.104.0.0/32", IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 255), nil}, {"135.104.0.0/32", IPv4(135, 104, 0, 0), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 255)}, nil},
{"0.0.0.0/24", IPv4(0, 0, 0, 0), IPv4Mask(255, 255, 255, 0), nil}, {"0.0.0.0/24", IPv4(0, 0, 0, 0), &IPNet{IPv4(0, 0, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
{"135.104.0.0/24", IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0), nil}, {"135.104.0.0/24", IPv4(135, 104, 0, 0), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
{"135.104.0.1/32", IPv4(135, 104, 0, 1), IPv4Mask(255, 255, 255, 255), nil}, {"135.104.0.1/32", IPv4(135, 104, 0, 1), &IPNet{IPv4(135, 104, 0, 1), IPv4Mask(255, 255, 255, 255)}, nil},
{"135.104.0.1/24", nil, nil, &ParseError{"CIDR address", "135.104.0.1/24"}}, {"135.104.0.1/24", IPv4(135, 104, 0, 1), &IPNet{IPv4(135, 104, 0, 0), IPv4Mask(255, 255, 255, 0)}, nil},
{"::1/128", ParseIP("::1"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")), nil}, {"::1/128", ParseIP("::1"), &IPNet{ParseIP("::1"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"))}, nil},
{"abcd:2345::/127", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe")), nil}, {"abcd:2345::/127", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe"))}, nil},
{"abcd:2345::/65", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:8000::")), nil}, {"abcd:2345::/65", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff:8000::"))}, nil},
{"abcd:2345::/64", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff::")), nil}, {"abcd:2345::/64", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:ffff::"))}, nil},
{"abcd:2345::/63", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:fffe::")), nil}, {"abcd:2345::/63", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:ffff:fffe::"))}, nil},
{"abcd:2345::/33", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:8000::")), nil}, {"abcd:2345::/33", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff:8000::"))}, nil},
{"abcd:2345::/32", ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff::")), nil}, {"abcd:2345::/32", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2345::"), IPMask(ParseIP("ffff:ffff::"))}, nil},
{"abcd:2344::/31", ParseIP("abcd:2344::"), IPMask(ParseIP("ffff:fffe::")), nil}, {"abcd:2344::/31", ParseIP("abcd:2344::"), &IPNet{ParseIP("abcd:2344::"), IPMask(ParseIP("ffff:fffe::"))}, nil},
{"abcd:2300::/24", ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::")), nil}, {"abcd:2300::/24", ParseIP("abcd:2300::"), &IPNet{ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::"))}, nil},
{"abcd:2345::/24", nil, nil, &ParseError{"CIDR address", "abcd:2345::/24"}}, {"abcd:2345::/24", ParseIP("abcd:2345::"), &IPNet{ParseIP("abcd:2300::"), IPMask(ParseIP("ffff:ff00::"))}, nil},
{"2001:DB8::/48", ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::")), nil}, {"2001:DB8::/48", ParseIP("2001:DB8::"), &IPNet{ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::"))}, nil},
{"2001:DB8::1/48", ParseIP("2001:DB8::1"), &IPNet{ParseIP("2001:DB8::"), IPMask(ParseIP("ffff:ffff:ffff::"))}, nil},
{"192.168.1.1/255.255.255.0", nil, nil, &ParseError{"CIDR address", "192.168.1.1/255.255.255.0"}},
{"192.168.1.1/35", nil, nil, &ParseError{"CIDR address", "192.168.1.1/35"}},
{"2001:db8::1/-1", nil, nil, &ParseError{"CIDR address", "2001:db8::1/-1"}},
{"", nil, nil, &ParseError{"CIDR address", ""}},
} }
func TestParseCIDR(t *testing.T) { func TestParseCIDR(t *testing.T) {
for _, tt := range parsecidrtests { for _, tt := range parsecidrtests {
if ip, mask, err := ParseCIDR(tt.in); !tt.ip.Equal(ip) || !isEqual(mask, tt.mask) || !reflect.DeepEqual(err, tt.err) { ip, net, err := ParseCIDR(tt.in)
t.Errorf("ParseCIDR(%q) = %v, %v, %v; want %v, %v, %v", tt.in, ip, mask, err, tt.ip, tt.mask, tt.err) if !reflect.DeepEqual(err, tt.err) {
t.Errorf("ParseCIDR(%q) = %v, %v; want %v, %v", tt.in, ip, net, tt.ip, tt.net)
}
if err == nil && (!tt.ip.Equal(ip) || !tt.net.IP.Equal(net.IP) || !isEqual(net.Mask, tt.net.Mask)) {
t.Errorf("ParseCIDR(%q) = %v, {%v, %v}; want %v {%v, %v}", tt.in, ip, net.IP, net.Mask, tt.ip, tt.net.IP, tt.net.Mask)
}
}
}
var ipnetcontainstests = []struct {
ip IP
net *IPNet
ok bool
}{
{IPv4(172, 16, 1, 1), &IPNet{IPv4(172, 16, 0, 0), CIDRMask(12, 32)}, true},
{IPv4(172, 24, 0, 1), &IPNet{IPv4(172, 16, 0, 0), CIDRMask(13, 32)}, false},
{IPv4(192, 168, 0, 3), &IPNet{IPv4(192, 168, 0, 0), IPv4Mask(0, 0, 255, 252)}, true},
{IPv4(192, 168, 0, 4), &IPNet{IPv4(192, 168, 0, 0), IPv4Mask(0, 255, 0, 252)}, false},
{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), CIDRMask(47, 128)}, true},
{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:2::"), CIDRMask(47, 128)}, false},
{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), IPMask(ParseIP("ffff:0:ffff::"))}, true},
{ParseIP("2001:db8:1:2::1"), &IPNet{ParseIP("2001:db8:1::"), IPMask(ParseIP("0:0:0:ffff::"))}, false},
}
func TestIPNetContains(t *testing.T) {
for _, tt := range ipnetcontainstests {
if ok := tt.net.Contains(tt.ip); ok != tt.ok {
t.Errorf("IPNet(%v).Contains(%v) = %v, want %v", tt.net, tt.ip, ok, tt.ok)
}
}
}
var ipnetstringtests = []struct {
in *IPNet
out string
}{
{&IPNet{IPv4(192, 168, 1, 0), CIDRMask(26, 32)}, "192.168.1.0/26"},
{&IPNet{IPv4(192, 168, 1, 0), IPv4Mask(255, 0, 255, 0)}, "192.168.1.0/ff00ff00"},
{&IPNet{ParseIP("2001:db8::"), CIDRMask(55, 128)}, "2001:db8::/55"},
{&IPNet{ParseIP("2001:db8::"), IPMask(ParseIP("8000:f123:0:cafe::"))}, "2001:db8::/8000f1230000cafe0000000000000000"},
}
func TestIPNetString(t *testing.T) {
for _, tt := range ipnetstringtests {
if out := tt.in.String(); out != tt.out {
t.Errorf("IPNet.String(%v) = %q, want %q", tt.in, out, tt.out)
}
}
}
var cidrmasktests = []struct {
ones int
bits int
out IPMask
}{
{0, 32, IPv4Mask(0, 0, 0, 0)},
{12, 32, IPv4Mask(255, 240, 0, 0)},
{24, 32, IPv4Mask(255, 255, 255, 0)},
{32, 32, IPv4Mask(255, 255, 255, 255)},
{0, 128, IPMask{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
{4, 128, IPMask{0xf0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
{48, 128, IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
{128, 128, IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}},
{33, 32, nil},
{32, 33, nil},
{-1, 128, nil},
{128, -1, nil},
}
func TestCIDRMask(t *testing.T) {
for _, tt := range cidrmasktests {
if out := CIDRMask(tt.ones, tt.bits); !isEqual(out, tt.out) {
t.Errorf("CIDRMask(%v, %v) = %v, want %v", tt.ones, tt.bits, out, tt.out)
}
}
}
var (
v4addr = IP{192, 168, 0, 1}
v4mappedv6addr = IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 192, 168, 0, 1}
v6addr = IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1}
v4mask = IPMask{255, 255, 255, 0}
v4mappedv6mask = IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 255, 255, 255, 0}
v6mask = IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0}
badaddr = IP{192, 168, 0}
badmask = IPMask{255, 255, 0}
v4maskzero = IPMask{0, 0, 0, 0}
)
var networknumberandmasktests = []struct {
in IPNet
out IPNet
}{
{IPNet{v4addr, v4mask}, IPNet{v4addr, v4mask}},
{IPNet{v4addr, v4mappedv6mask}, IPNet{v4addr, v4mask}},
{IPNet{v4mappedv6addr, v4mappedv6mask}, IPNet{v4addr, v4mask}},
{IPNet{v4mappedv6addr, v6mask}, IPNet{v4addr, v4maskzero}},
{IPNet{v4addr, v6mask}, IPNet{v4addr, v4maskzero}},
{IPNet{v6addr, v6mask}, IPNet{v6addr, v6mask}},
{IPNet{v6addr, v4mappedv6mask}, IPNet{v6addr, v4mappedv6mask}},
{in: IPNet{v6addr, v4mask}},
{in: IPNet{v4addr, badmask}},
{in: IPNet{v4mappedv6addr, badmask}},
{in: IPNet{v6addr, badmask}},
{in: IPNet{badaddr, v4mask}},
{in: IPNet{badaddr, v4mappedv6mask}},
{in: IPNet{badaddr, v6mask}},
{in: IPNet{badaddr, badmask}},
}
func TestNetworkNumberAndMask(t *testing.T) {
for _, tt := range networknumberandmasktests {
ip, m := networkNumberAndMask(&tt.in)
out := &IPNet{ip, m}
if !reflect.DeepEqual(&tt.out, out) {
t.Errorf("networkNumberAndMask(%v) = %v; want %v", tt.in, out, &tt.out)
} }
} }
} }
@ -191,10 +312,10 @@ var ipaftests = []struct {
func TestIPAddrFamily(t *testing.T) { func TestIPAddrFamily(t *testing.T) {
for _, tt := range ipaftests { for _, tt := range ipaftests {
if af := tt.in.To4() != nil; af != tt.af4 { if af := tt.in.To4() != nil; af != tt.af4 {
t.Errorf("verifying IPv4 address family for %#q = %v, want %v", tt.in, af, tt.af4) t.Errorf("verifying IPv4 address family for %q = %v, want %v", tt.in, af, tt.af4)
} }
if af := len(tt.in) == IPv6len && tt.in.To4() == nil; af != tt.af6 { if af := len(tt.in) == IPv6len && tt.in.To4() == nil; af != tt.af6 {
t.Errorf("verifying IPv6 address family for %#q = %v, want %v", tt.in, af, tt.af6) t.Errorf("verifying IPv6 address family for %q = %v, want %v", tt.in, af, tt.af6)
} }
} }
} }
@ -242,7 +363,7 @@ func name(f interface{}) string {
func TestIPAddrScope(t *testing.T) { func TestIPAddrScope(t *testing.T) {
for _, tt := range ipscopetests { for _, tt := range ipscopetests {
if ok := tt.scope(tt.in); ok != tt.ok { if ok := tt.scope(tt.in); ok != tt.ok {
t.Errorf("%s(%#q) = %v, want %v", name(tt.scope), tt.in, ok, tt.ok) t.Errorf("%s(%q) = %v, want %v", name(tt.scope), tt.in, ok, tt.ok)
} }
} }
} }