if ones < 0 || ones > bits {
return nil
}
- l := bits / 8
- m := make(IPMask, l)
+ return putCIDRMask(nil, ones, bits/8)
+}
+
+// putCIDRMask will put an IPMask into `m` consisting of `ones` 1 bits
+// followed by 0s up to a total length of `bits' bits if the length
+// of m is < `l` bytes and returns the same slice m. If m did not have
+// sufficient length for the mask l a new m is returned instead.
+func putCIDRMask(m IPMask, ones, bits int) IPMask {
+ if len(m) < bits {
+ m = make(IPMask, bits)
+ }
+
n := uint(ones)
- for i := 0; i < l; i++ {
+ for i := 0; i < bits; i++ {
if n >= 8 {
m[i] = 0xff
n -= 8
// Mask returns the result of masking the IP address ip with mask.
func (ip IP) Mask(mask IPMask) IP {
+ return ipMaskWithBuf(nil, ip, mask)
+}
+
+// ipMaskWithBuf implements the IP.Mask method, but containing an
+// opitional optional bufer to use for the return value. If the buf is
+// too small, a new one is allocated.
+func ipMaskWithBuf(buf, ip IP, mask IPMask) []byte {
if len(mask) == IPv6len && len(ip) == IPv4len && allFF(mask[:12]) {
mask = mask[12:]
}
if n != len(mask) {
return nil
}
- out := make(IP, n)
+ if len(buf) < n {
+ buf = make(IP, n)
+ }
for i := 0; i < n; i++ {
- out[i] = ip[i] & mask[i]
+ buf[i] = ip[i] & mask[i]
}
- return out
+ return buf
}
// ubtoa encodes the string form of the integer v to dst[start:] and
// Parse IPv4 address (d.d.d.d).
func parseIPv4(s string) IP {
var p [IPv4len]byte
+ if !parseIntoIPv4(p[:], s) {
+ return nil
+ }
+ return IPv4(p[0], p[1], p[2], p[3])
+}
+
+// parseIntoIPv4 parses s as an IPv4 address and parses it into
+// p, which must be at least IPv4len bytes long. It reports
+// whether the parse was successful.
+func parseIntoIPv4(p []byte, s string) bool {
for i := 0; i < IPv4len; i++ {
if len(s) == 0 {
// Missing octets.
- return nil
+ return false
}
if i > 0 {
if s[0] != '.' {
- return nil
+ return false
}
s = s[1:]
}
n, c, ok := dtoi(s)
if !ok || n > 0xFF {
- return nil
+ return false
}
s = s[c:]
p[i] = byte(n)
}
- if len(s) != 0 {
- return nil
- }
- return IPv4(p[0], p[1], p[2], p[3])
+ return len(s) == 0
}
// parseIPv6Zone parses s as a literal IPv6 address and its associated zone
// parseIPv6 parses s as a literal IPv6 address described in RFC 4291
// and RFC 5952.
func parseIPv6(s string) (ip IP) {
- ip = make(IP, IPv6len)
+ if ip = make(IP, IPv6len); !parseIntoIPv6(ip, s) {
+ ip = nil
+ }
+ return
+}
+
+// parseIntoIPv6 parses s as a literal IPv6 address described in RFC
+// 4291 and RFC 5952 and populates ip. It reports whether the parse
+// was successful.
+func parseIntoIPv6(ip IP, s string) bool {
ellipsis := -1 // position of ellipsis in ip
// Might have leading ellipsis
s = s[2:]
// Might be only ellipsis
if len(s) == 0 {
- return ip
+ return true
}
}
// Hex number.
n, c, ok := xtoi(s)
if !ok || n > 0xFFFF {
- return nil
+ return false
}
// If followed by dot, might be in trailing IPv4.
if c < len(s) && s[c] == '.' {
if ellipsis < 0 && i != IPv6len-IPv4len {
// Not the right place.
- return nil
+ return false
}
if i+IPv4len > IPv6len {
// Not enough room.
- return nil
+ return false
}
ip4 := parseIPv4(s)
if ip4 == nil {
- return nil
+ return false
}
ip[i] = ip4[12]
ip[i+1] = ip4[13]
// Otherwise must be followed by colon and more.
if s[0] != ':' || len(s) == 1 {
- return nil
+ return false
}
s = s[1:]
// Look for ellipsis.
if s[0] == ':' {
if ellipsis >= 0 { // already have one
- return nil
+ return false
}
ellipsis = i
s = s[1:]
// Must have used entire string.
if len(s) != 0 {
- return nil
+ return false
}
// If didn't parse enough, expand ellipsis.
if i < IPv6len {
if ellipsis < 0 {
- return nil
+ return false
}
n := IPv6len - i
for j := i - 1; j >= ellipsis; j-- {
}
} else if ellipsis >= 0 {
// Ellipsis must represent at least one 0 group.
- return nil
+ return false
}
- return ip
+ return true
}
// ParseIP parses s as an IP address, returning the result.
// If s is not a valid textual representation of an IP address,
// ParseIP returns nil.
func ParseIP(s string) IP {
+ switch n := strToIPvLen(s); n {
+ case IPv4len:
+ return parseIPv4(s)
+ case IPv6len:
+ return parseIPv6(s)
+ default:
+ return nil
+ }
+}
+
+// strToIPvLen reports the expected length of the parsed IP adress
+// given its ASCII representation in s. It returns IPv4len, IPv6len,
+// or -1.
+func strToIPvLen(s string) int {
for i := 0; i < len(s); i++ {
switch s[i] {
case '.':
- return parseIPv4(s)
+ return IPv4len
case ':':
- return parseIPv6(s)
+ return IPv6len
}
}
- return nil
+ return -1
}
// parseIPZone parses s as an IP address, return it and its associated zone
if i < 0 {
return nil, nil, &ParseError{Type: "CIDR address", Text: s}
}
- addr, mask := s[:i], s[i+1:]
- iplen := IPv4len
- ip := parseIPv4(addr)
- if ip == nil {
- iplen = IPv6len
- ip = parseIPv6(addr)
+
+ iplen := strToIPvLen(s[:i])
+ if iplen < 0 {
+ return nil, nil, &ParseError{Type: "CIDR address", Text: s}
}
- n, i, ok := dtoi(mask)
- if ip == nil || !ok || i != len(mask) || n < 0 || n > 8*iplen {
+
+ nwlen, y, ok := dtoi(s[i+1:])
+ if !ok || y != len(s[i+1:]) || nwlen < 0 || nwlen > 8*iplen {
return nil, nil, &ParseError{Type: "CIDR address", Text: s}
}
- m := CIDRMask(n, 8*iplen)
- return ip, &IPNet{IP: ip.Mask(m), Mask: m}, nil
+
+ var (
+ buf []byte
+ ipn *IPNet
+ )
+ switch iplen {
+ case IPv4len:
+ var block struct {
+ ipn IPNet
+ arr [IPv6len + (IPv4len * 2)]byte
+ }
+ ipn = &block.ipn
+ buf = block.arr[:]
+ copy(buf, v4InV6Prefix)
+ if !parseIntoIPv4(buf[len(v4InV6Prefix):], s[:i]) {
+ return nil, nil, &ParseError{Type: "CIDR address", Text: s}
+ }
+ case IPv6len:
+ var block struct {
+ ipn IPNet
+ arr [IPv6len * 3]byte
+ }
+ ipn = &block.ipn
+ buf = block.arr[:]
+ if !parseIntoIPv6(buf, s[:i]) {
+ return nil, nil, &ParseError{Type: "CIDR address", Text: s}
+ }
+ default:
+ return nil, nil, &ParseError{Type: "CIDR address", Text: s}
+ }
+
+ ip := buf[:IPv6len:IPv6len]
+ buf = buf[IPv6len:]
+
+ ipn.Mask = putCIDRMask(buf[:iplen:iplen], nwlen, iplen)
+ buf = buf[iplen:]
+
+ ipn.IP = ipMaskWithBuf(buf[:iplen:iplen], ip, ipn.Mask)
+ return ip, ipn, nil
}
func TestParseIP(t *testing.T) {
for _, tt := range parseIPTests {
- if out := ParseIP(tt.in); !reflect.DeepEqual(out, tt.out) {
+ out := ParseIP(tt.in)
+ if !reflect.DeepEqual(out, tt.out) {
t.Errorf("ParseIP(%q) = %v, want %v", tt.in, out, tt.out)
}
+ if exp, got := cap(out), len(out); exp != got {
+ t.Fatalf("ParseIP(%q) cap %v; want %v", tt.in, exp, got)
+ }
if tt.in == "" {
// Tested in TestMarshalEmptyIP below.
continue
}
- var out IP
+ out = nil
if err := out.UnmarshalText([]byte(tt.in)); !reflect.DeepEqual(out, tt.out) || (tt.out == nil) != (err != nil) {
t.Errorf("IP.UnmarshalText(%q) = %v, %v, want %v", tt.in, out, err, tt.out)
}
testHookUninstaller.Do(uninstallTestHooks)
for i := 0; i < b.N; i++ {
+ b.ReportAllocs()
for _, tt := range parseIPTests {
ParseIP(tt.in)
}
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) || !reflect.DeepEqual(net.Mask, tt.net.Mask)) {
+ if err != nil {
+ continue
+ }
+ if !tt.ip.Equal(ip) || !tt.net.IP.Equal(net.IP) || !reflect.DeepEqual(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)
}
+ if exp, got := cap(ip), len(ip); exp != got {
+ t.Fatalf("ParseCIDR(%q) ip cap %v; want %v", tt.in, exp, got)
+ }
+ if exp, got := cap(net.IP), len(net.IP); exp != got {
+ t.Fatalf("ParseCIDR(%q) net.IP cap %v; want %v", tt.in, exp, got)
+ }
+ if exp, got := cap(net.Mask), len(net.Mask); exp != got {
+ t.Fatalf("ParseCIDR(%q) net.Mask cap %v; want %v", tt.in, exp, got)
+ }
}
}
+func BenchmarkParseCIDR(b *testing.B) {
+ testHookUninstaller.Do(uninstallTestHooks)
+
+ b.Run("IPv4", func(b *testing.B) {
+ b.ReportAllocs()
+ for i := 0; i < b.N; i++ {
+ ParseCIDR("135.104.0.1/24")
+ }
+ })
+ b.Run("IPv6", func(b *testing.B) {
+ b.ReportAllocs()
+ for i := 0; i < b.N; i++ {
+ ParseCIDR("2001:DB8::1/48")
+ }
+ })
+}
+
var ipNetContainsTests = []struct {
ip IP
net *IPNet