mirror of https://github.com/golang/go.git
net: halve the allocs in ParseCIDR by sharing slice backing
Share a slice backing between the host address, network ip and mask.
Add tests to verify that each slice header has len==cap to prevent
introducing new behavior into Go programs. This has a small tradeoff
of allocating a larger slice backing when the address is invalid.
Earlier error detection of invalid prefix length helps balance this
cost and a new benchmark for ParseCIDR helps measure it.
This yields a ~22% speedup for all nil err cidr tests:
name old time/op new time/op delta
ParseCIDR/IPv4-24 9.17µs ± 6% 7.20µs ± 7% -21.47% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 9.02µs ± 6% 6.95µs ± 9% -23.02% (p=0.000 n=20+20)
ParseCIDR/IPv4-24 1.51kB ± 0% 1.55kB ± 0% +2.65% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 1.51kB ± 0% 1.55kB ± 0% +2.65% (p=0.000 n=20+20)
ParseCIDR/IPv4-24 68.0 ± 0% 34.0 ± 0% -50.00% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 68.0 ± 0% 34.0 ± 0% -50.00% (p=0.000 n=20+20)
Including non-nil err cidr tests gains around 25%~:
name old time/op new time/op delta
ParseCIDR/IPv4-24 11.8µs ±11% 8.9µs ± 8% -24.88% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 11.7µs ± 7% 8.7µs ± 5% -25.93% (p=0.000 n=20+20)
ParseCIDR/IPv4-24 1.98kB ± 0% 2.00kB ± 0% +1.21% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 1.98kB ± 0% 2.00kB ± 0% +1.21% (p=0.000 n=20+20)
ParseCIDR/IPv4-24 87.0 ± 0% 48.0 ± 0% -44.83% (p=0.000 n=20+20)
ParseCIDR/IPv6-24 87.0 ± 0% 48.0 ± 0% -44.83% (p=0.000 n=20+20)
Change-Id: I17f33c9049f7875b6ebdfde1f80b386a7aef9b94
GitHub-Last-Rev: 0a031f44b4
GitHub-Pull-Request: golang/go#26948
Reviewed-on: https://go-review.googlesource.com/c/go/+/129118
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Chris Stockton
Brad Fitzpatrick
parent
1fd3f8bd67
commit
aff3aaa47f
165
src/net/ip.go
165
src/net/ip.go
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@ -75,10 +75,20 @@ func CIDRMask(ones, bits int) IPMask {
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if ones < 0 || ones > bits {
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return nil
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}
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l := bits / 8
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m := make(IPMask, l)
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return putCIDRMask(nil, ones, bits/8)
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}
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// putCIDRMask will put an IPMask into `m` consisting of `ones` 1 bits
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// followed by 0s up to a total length of `bits' bits if the length
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// of m is < `l` bytes and returns the same slice m. If m did not have
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// sufficient length for the mask l a new m is returned instead.
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func putCIDRMask(m IPMask, ones, bits int) IPMask {
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if len(m) < bits {
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m = make(IPMask, bits)
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}
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n := uint(ones)
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for i := 0; i < l; i++ {
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for i := 0; i < bits; i++ {
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if n >= 8 {
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m[i] = 0xff
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n -= 8
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@ -243,6 +253,13 @@ func allFF(b []byte) bool {
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// Mask returns the result of masking the IP address ip with mask.
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func (ip IP) Mask(mask IPMask) IP {
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return ipMaskWithBuf(nil, ip, mask)
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}
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// ipMaskWithBuf implements the IP.Mask method, but containing an
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// opitional optional bufer to use for the return value. If the buf is
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// too small, a new one is allocated.
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func ipMaskWithBuf(buf, ip IP, mask IPMask) []byte {
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if len(mask) == IPv6len && len(ip) == IPv4len && allFF(mask[:12]) {
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mask = mask[12:]
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}
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@ -253,11 +270,13 @@ func (ip IP) Mask(mask IPMask) IP {
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if n != len(mask) {
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return nil
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}
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out := make(IP, n)
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for i := 0; i < n; i++ {
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out[i] = ip[i] & mask[i]
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if len(buf) < n {
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buf = make(IP, n)
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}
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return out
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for i := 0; i < n; i++ {
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buf[i] = ip[i] & mask[i]
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}
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return buf
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}
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// ubtoa encodes the string form of the integer v to dst[start:] and
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@ -534,28 +553,35 @@ func (n *IPNet) String() string {
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// Parse IPv4 address (d.d.d.d).
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func parseIPv4(s string) IP {
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var p [IPv4len]byte
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if !parseIntoIPv4(p[:], s) {
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return nil
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}
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return IPv4(p[0], p[1], p[2], p[3])
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}
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// parseIntoIPv4 parses s as an IPv4 address and parses it into
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// p, which must be at least IPv4len bytes long. It reports
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// whether the parse was successful.
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func parseIntoIPv4(p []byte, s string) bool {
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for i := 0; i < IPv4len; i++ {
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if len(s) == 0 {
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// Missing octets.
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return nil
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return false
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}
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if i > 0 {
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if s[0] != '.' {
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return nil
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return false
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}
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s = s[1:]
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}
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n, c, ok := dtoi(s)
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if !ok || n > 0xFF {
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return nil
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return false
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}
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s = s[c:]
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p[i] = byte(n)
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}
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if len(s) != 0 {
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return nil
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}
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return IPv4(p[0], p[1], p[2], p[3])
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return len(s) == 0
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}
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// parseIPv6Zone parses s as a literal IPv6 address and its associated zone
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@ -568,7 +594,16 @@ func parseIPv6Zone(s string) (IP, string) {
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// parseIPv6 parses s as a literal IPv6 address described in RFC 4291
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// and RFC 5952.
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func parseIPv6(s string) (ip IP) {
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ip = make(IP, IPv6len)
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if ip = make(IP, IPv6len); !parseIntoIPv6(ip, s) {
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ip = nil
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}
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return
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}
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// parseIntoIPv6 parses s as a literal IPv6 address described in RFC
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// 4291 and RFC 5952 and populates ip. It reports whether the parse
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// was successful.
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func parseIntoIPv6(ip IP, s string) bool {
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ellipsis := -1 // position of ellipsis in ip
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// Might have leading ellipsis
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@ -577,7 +612,7 @@ func parseIPv6(s string) (ip IP) {
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s = s[2:]
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// Might be only ellipsis
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if len(s) == 0 {
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return ip
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return true
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}
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}
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@ -587,22 +622,22 @@ func parseIPv6(s string) (ip IP) {
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// Hex number.
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n, c, ok := xtoi(s)
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if !ok || n > 0xFFFF {
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return nil
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return false
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}
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// If followed by dot, might be in trailing IPv4.
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if c < len(s) && s[c] == '.' {
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if ellipsis < 0 && i != IPv6len-IPv4len {
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// Not the right place.
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return nil
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return false
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}
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if i+IPv4len > IPv6len {
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// Not enough room.
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return nil
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return false
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}
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ip4 := parseIPv4(s)
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if ip4 == nil {
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return nil
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return false
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}
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ip[i] = ip4[12]
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ip[i+1] = ip4[13]
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@ -626,14 +661,14 @@ func parseIPv6(s string) (ip IP) {
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// Otherwise must be followed by colon and more.
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if s[0] != ':' || len(s) == 1 {
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return nil
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return false
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}
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s = s[1:]
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// Look for ellipsis.
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if s[0] == ':' {
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if ellipsis >= 0 { // already have one
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return nil
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return false
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}
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ellipsis = i
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s = s[1:]
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@ -645,13 +680,13 @@ func parseIPv6(s string) (ip IP) {
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// Must have used entire string.
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if len(s) != 0 {
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return nil
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return false
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}
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// If didn't parse enough, expand ellipsis.
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if i < IPv6len {
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if ellipsis < 0 {
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return nil
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return false
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}
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n := IPv6len - i
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for j := i - 1; j >= ellipsis; j-- {
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@ -662,9 +697,9 @@ func parseIPv6(s string) (ip IP) {
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}
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} else if ellipsis >= 0 {
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// Ellipsis must represent at least one 0 group.
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return nil
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return false
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}
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return ip
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return true
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}
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// ParseIP parses s as an IP address, returning the result.
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@ -673,15 +708,29 @@ func parseIPv6(s string) (ip IP) {
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// If s is not a valid textual representation of an IP address,
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// ParseIP returns nil.
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func ParseIP(s string) IP {
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switch n := strToIPvLen(s); n {
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case IPv4len:
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return parseIPv4(s)
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case IPv6len:
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return parseIPv6(s)
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default:
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return nil
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}
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}
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// strToIPvLen reports the expected length of the parsed IP adress
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// given its ASCII representation in s. It returns IPv4len, IPv6len,
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// or -1.
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func strToIPvLen(s string) int {
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for i := 0; i < len(s); i++ {
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switch s[i] {
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case '.':
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return parseIPv4(s)
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return IPv4len
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case ':':
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return parseIPv6(s)
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return IPv6len
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}
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}
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return nil
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return -1
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}
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// parseIPZone parses s as an IP address, return it and its associated zone
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@ -711,17 +760,53 @@ func ParseCIDR(s string) (IP, *IPNet, error) {
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if i < 0 {
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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addr, mask := s[:i], s[i+1:]
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iplen := IPv4len
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ip := parseIPv4(addr)
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if ip == nil {
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iplen = IPv6len
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ip = parseIPv6(addr)
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}
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n, i, ok := dtoi(mask)
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if ip == nil || !ok || i != len(mask) || n < 0 || n > 8*iplen {
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iplen := strToIPvLen(s[:i])
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if iplen < 0 {
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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m := CIDRMask(n, 8*iplen)
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return ip, &IPNet{IP: ip.Mask(m), Mask: m}, nil
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nwlen, y, ok := dtoi(s[i+1:])
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if !ok || y != len(s[i+1:]) || nwlen < 0 || nwlen > 8*iplen {
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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var (
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buf []byte
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ipn *IPNet
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)
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switch iplen {
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case IPv4len:
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var block struct {
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ipn IPNet
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arr [IPv6len + (IPv4len * 2)]byte
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}
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ipn = &block.ipn
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buf = block.arr[:]
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copy(buf, v4InV6Prefix)
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if !parseIntoIPv4(buf[len(v4InV6Prefix):], s[:i]) {
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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case IPv6len:
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var block struct {
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ipn IPNet
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arr [IPv6len * 3]byte
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}
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ipn = &block.ipn
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buf = block.arr[:]
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if !parseIntoIPv6(buf, s[:i]) {
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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default:
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return nil, nil, &ParseError{Type: "CIDR address", Text: s}
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}
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ip := buf[:IPv6len:IPv6len]
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buf = buf[IPv6len:]
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ipn.Mask = putCIDRMask(buf[:iplen:iplen], nwlen, iplen)
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buf = buf[iplen:]
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ipn.IP = ipMaskWithBuf(buf[:iplen:iplen], ip, ipn.Mask)
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return ip, ipn, nil
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}
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@ -46,14 +46,18 @@ var parseIPTests = []struct {
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func TestParseIP(t *testing.T) {
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for _, tt := range parseIPTests {
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if out := ParseIP(tt.in); !reflect.DeepEqual(out, tt.out) {
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out := ParseIP(tt.in)
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if !reflect.DeepEqual(out, tt.out) {
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t.Errorf("ParseIP(%q) = %v, want %v", tt.in, out, tt.out)
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}
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if exp, got := cap(out), len(out); exp != got {
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t.Fatalf("ParseIP(%q) cap %v; want %v", tt.in, exp, got)
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}
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if tt.in == "" {
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// Tested in TestMarshalEmptyIP below.
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continue
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}
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var out IP
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out = nil
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if err := out.UnmarshalText([]byte(tt.in)); !reflect.DeepEqual(out, tt.out) || (tt.out == nil) != (err != nil) {
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t.Errorf("IP.UnmarshalText(%q) = %v, %v, want %v", tt.in, out, err, tt.out)
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}
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@ -107,6 +111,7 @@ func BenchmarkParseIP(b *testing.B) {
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testHookUninstaller.Do(uninstallTestHooks)
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for i := 0; i < b.N; i++ {
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b.ReportAllocs()
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for _, tt := range parseIPTests {
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ParseIP(tt.in)
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}
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@ -366,12 +371,41 @@ func TestParseCIDR(t *testing.T) {
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if !reflect.DeepEqual(err, tt.err) {
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t.Errorf("ParseCIDR(%q) = %v, %v; want %v, %v", tt.in, ip, net, tt.ip, tt.net)
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}
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if err == nil && (!tt.ip.Equal(ip) || !tt.net.IP.Equal(net.IP) || !reflect.DeepEqual(net.Mask, tt.net.Mask)) {
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if err != nil {
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continue
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}
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if !tt.ip.Equal(ip) || !tt.net.IP.Equal(net.IP) || !reflect.DeepEqual(net.Mask, tt.net.Mask) {
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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)
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}
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if exp, got := cap(ip), len(ip); exp != got {
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t.Fatalf("ParseCIDR(%q) ip cap %v; want %v", tt.in, exp, got)
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}
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if exp, got := cap(net.IP), len(net.IP); exp != got {
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t.Fatalf("ParseCIDR(%q) net.IP cap %v; want %v", tt.in, exp, got)
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}
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if exp, got := cap(net.Mask), len(net.Mask); exp != got {
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t.Fatalf("ParseCIDR(%q) net.Mask cap %v; want %v", tt.in, exp, got)
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}
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}
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}
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func BenchmarkParseCIDR(b *testing.B) {
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testHookUninstaller.Do(uninstallTestHooks)
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b.Run("IPv4", func(b *testing.B) {
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b.ReportAllocs()
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for i := 0; i < b.N; i++ {
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ParseCIDR("135.104.0.1/24")
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}
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})
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b.Run("IPv6", func(b *testing.B) {
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b.ReportAllocs()
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for i := 0; i < b.N; i++ {
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ParseCIDR("2001:DB8::1/48")
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}
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})
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}
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var ipNetContainsTests = []struct {
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ip IP
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net *IPNet
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Loading…
Reference in New Issue