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net: change the internal form of IPMask for IPv4

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This CL changes the internal form of IPMask for IPv4
from 16-byte to 4-byte, also adds Size method to IPMask
struct and changes output string format of IPMask.String
method.

R=rsc
CC=golang-dev
https://golang.org/cl/4950046
This commit is contained in:
Mikio Hara 2011-08-29 10:49:03 -04:00 committed by Russ Cox
parent 1952eb5010
commit 683df29f7c
2 changed files with 87 additions and 51 deletions
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67
src/pkg/net/ip.go
View File

@ -21,8 +21,8 @@ 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 (IP v4) // Functions in this package accept either 4-byte (IPv4)
// or 16-byte (IP v6) arrays as input. Unless otherwise // or 16-byte (IPv6) arrays as input. Unless otherwise
// specified, functions in this package always return // specified, functions in this package always return
// IP addresses in 16-byte form using the canonical // IP addresses in 16-byte form using the canonical
// embedding. // embedding.
@ -51,17 +51,14 @@ func IPv4(a, b, c, d byte) IP {
var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff} var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}
// IPv4Mask returns the IP mask (in 16-byte form) of the // IPv4Mask returns the IP mask (in 4-byte form) of the
// IPv4 mask a.b.c.d. // IPv4 mask a.b.c.d.
func IPv4Mask(a, b, c, d byte) IPMask { func IPv4Mask(a, b, c, d byte) IPMask {
p := make(IPMask, IPv6len) p := make(IPMask, IPv4len)
for i := 0; i < 12; i++ { p[0] = a
p[i] = 0xff p[1] = b
} p[2] = c
p[12] = a p[3] = d
p[13] = b
p[14] = c
p[15] = d
return p return p
} }
@ -213,13 +210,13 @@ func allFF(b []byte) bool {
// Mask returns the result of masking the IP address ip with mask. // Mask returns the result of masking the IP address ip with mask.
func (ip IP) Mask(mask IPMask) IP { func (ip IP) Mask(mask IPMask) IP {
n := len(ip)
if len(mask) == IPv6len && len(ip) == IPv4len && allFF(mask[:12]) { if len(mask) == IPv6len && len(ip) == IPv4len && allFF(mask[:12]) {
mask = mask[12:] mask = mask[12:]
} }
if len(mask) == IPv4len && len(ip) == IPv6len && bytesEqual(ip[:12], v4InV6Prefix) { if len(mask) == IPv4len && len(ip) == IPv6len && bytesEqual(ip[:12], v4InV6Prefix) {
ip = ip[12:] ip = ip[12:]
} }
n := len(ip)
if n != len(mask) { if n != len(mask) {
return nil return nil
} }
@ -238,7 +235,7 @@ func (ip IP) String() string {
p := ip p := ip
if len(ip) == 0 { if len(ip) == 0 {
return "" return "<nil>"
} }
// If IPv4, use dotted notation. // If IPv4, use dotted notation.
@ -345,25 +342,27 @@ func simpleMaskLength(mask IPMask) int {
return n return n
} }
// String returns the string representation of mask. // Size returns the number of leading ones and total bits in the mask.
// If the mask is in the canonical form--ones followed by zeros--the // If the mask is not in the canonical form--ones followed by zeros--then
// string representation is just the decimal number of ones. // Size returns 0, 0.
// If the mask is in a non-canonical form, it is formatted func (m IPMask) Size() (ones, bits int) {
// as an IP address. ones, bits = simpleMaskLength(m), len(m)*8
func (mask IPMask) String() string { if ones == -1 {
switch len(mask) { return 0, 0
case IPv4len:
n := simpleMaskLength(mask)
if n >= 0 {
return itod(uint(n + (IPv6len-IPv4len)*8))
} }
case IPv6len: return
n := simpleMaskLength(mask) }
if n >= 12*8 {
return itod(uint(n - 12*8)) // String returns the hexadecimal form of m, with no punctuation.
func (m IPMask) String() string {
s := ""
for _, b := range m {
s += itox(uint(b), 2)
} }
if len(s) == 0 {
return "<nil>"
} }
return IP(mask).String() return s
} }
// Parse IPv4 address (d.d.d.d). // Parse IPv4 address (d.d.d.d).
@ -535,7 +534,7 @@ 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", "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) { func ParseCIDR(s string) (ip IP, mask IPMask, err os.Error) {
i := byteIndex(s, '/') i := byteIndex(s, '/')
@ -571,8 +570,12 @@ func ParseCIDR(s string) (ip IP, mask IPMask, err os.Error) {
} }
} }
// address must not have any bits not in mask // address must not have any bits not in mask
for i := range ip { mip := ip
if ip[i]&^mask[i] != 0 { if iplen == IPv4len {
mip = ip[12:]
}
for i := range mip {
if mip[i]&^mask[i] != 0 {
return nil, nil, &ParseError{"CIDR address", s} return nil, nil, &ParseError{"CIDR address", s}
} }
} }

67
src/pkg/net/ip_test.go
View File

@ -49,22 +49,15 @@ var ipstringtests = []struct {
out string out string
}{ }{
// cf. RFC 5952 (A Recommendation for IPv6 Address Text Representation) // cf. RFC 5952 (A Recommendation for IPv6 Address Text Representation)
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0x1, 0x23, 0, 0x12, 0, 0x1}, "2001:db8::123:12:1"},
"2001:db8::123:12:1"}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x1}, "2001:db8::1"},
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x1}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1}, "2001:db8:0:1:0:1:0:1"},
"2001:db8::1"}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0}, "2001:db8:1:0:1:0:1:0"},
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1}, {IP{0x20, 0x1, 0, 0, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1}, "2001::1:0:0:1"},
"2001:db8:0:1:0:1:0:1"}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0}, "2001:db8:0:0:1::"},
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0x1, 0, 0, 0, 0x1, 0, 0, 0, 0x1, 0, 0}, {IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1}, "2001:db8::1:0:0:1"},
"2001:db8:1:0:1:0:1:0"}, {IP{0x20, 0x1, 0xD, 0xB8, 0, 0, 0, 0, 0, 0xA, 0, 0xB, 0, 0xC, 0, 0xD}, "2001:db8::a:b:c:d"},
{IP{0x20, 0x1, 0, 0, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1}, {nil, "<nil>"},
"2001::1:0:0:1"},
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0},
"2001:db8:0:0:1::"},
{IP{0x20, 0x1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0x1, 0, 0, 0, 0, 0, 0x1},
"2001:db8::1:0:0:1"},
{IP{0x20, 0x1, 0xD, 0xB8, 0, 0, 0, 0, 0, 0xA, 0, 0xB, 0, 0xC, 0, 0xD},
"2001:db8::a:b:c:d"},
} }
func TestIPString(t *testing.T) { func TestIPString(t *testing.T) {
@ -75,6 +68,46 @@ func TestIPString(t *testing.T) {
} }
} }
var ipmasktests = []struct {
in IP
mask IPMask
out IP
}{
{IPv4(192, 168, 1, 127), IPv4Mask(255, 255, 255, 128), IPv4(192, 168, 1, 0)},
{IPv4(192, 168, 1, 127), IPMask(ParseIP("255.255.255.192")), IPv4(192, 168, 1, 64)},
{IPv4(192, 168, 1, 127), IPMask(ParseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffe0")), IPv4(192, 168, 1, 96)},
{IPv4(192, 168, 1, 127), IPv4Mask(255, 0, 255, 0), IPv4(192, 0, 1, 0)},
{ParseIP("2001:db8::1"), IPMask(ParseIP("ffff:ff80::")), ParseIP("2001:d80::")},
{ParseIP("2001:db8::1"), IPMask(ParseIP("f0f0:0f0f::")), ParseIP("2000:d08::")},
}
func TestIPMask(t *testing.T) {
for _, tt := range ipmasktests {
if out := tt.in.Mask(tt.mask); out == nil || !tt.out.Equal(out) {
t.Errorf("IP(%v).Mask(%v) = %v, want %v", tt.in, tt.mask, out, tt.out)
}
}
}
var ipmaskstringtests = []struct {
in IPMask
out string
}{
{IPv4Mask(255, 255, 255, 240), "fffffff0"},
{IPv4Mask(255, 0, 128, 0), "ff008000"},
{IPMask(ParseIP("ffff:ff80::")), "ffffff80000000000000000000000000"},
{IPMask(ParseIP("ef00:ff80::cafe:0")), "ef00ff800000000000000000cafe0000"},
{nil, "<nil>"},
}
func TestIPMaskString(t *testing.T) {
for _, tt := range ipmaskstringtests {
if out := tt.in.String(); out != tt.out {
t.Errorf("IPMask.String(%v) = %q, want %q", tt.in, out, tt.out)
}
}
}
var parsecidrtests = []struct { var parsecidrtests = []struct {
in string in string
ip IP ip IP
@ -101,7 +134,7 @@ var parsecidrtests = []struct {
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); !isEqual(ip, tt.ip) || !isEqual(mask, tt.mask) || !reflect.DeepEqual(err, tt.err) { if ip, mask, err := ParseCIDR(tt.in); !tt.ip.Equal(ip) || !isEqual(mask, tt.mask) || !reflect.DeepEqual(err, tt.err) {
t.Errorf("ParseCIDR(%q) = %v, %v, %v; want %v, %v, %v", tt.in, ip, mask, err, tt.ip, tt.mask, tt.err) t.Errorf("ParseCIDR(%q) = %v, %v, %v; want %v, %v, %v", tt.in, ip, mask, err, tt.ip, tt.mask, tt.err)
} }
} }