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pkg/net: add ParseCIDR to extract CIDR information
For example, net.ParseCIDR("10.20.30.40/24") returns:
{
prefix_mask: "255.255.255.0"
prefix_len: 24
prefix_addr: "10.20.30.0"
broadcast_addr: "10.20.30.255"
}
The names are chosen to loosely follow the API in Go's net/netip
as well as the basic terminology used on Wikipedia.
We might add more fields to this struct in the future,
as long as it's information that is useful and cheap to compute.
Fixes #4236.
Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I072c85e62976f7ce1041b00d406938b04638f779
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1229761
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Matthew Sackman <matthew@cue.works>
+154
+2
pkg/gen.go
+2
pkg/gen.go
···
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// use CUE function signatures to validate their parameters and results.
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case "*cuelang.org/go/pkg/time.Parts":
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return "adt.StructKind"
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+
case "*cuelang.org/go/pkg/net.ParsedCIDR":
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return "adt.StructKind"
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}
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log.Fatal("adtKind: unhandled Go type ", typ.String())
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return ""
+50
pkg/net/ip.go
+50
pkg/net/ip.go
···
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return netip.PrefixFrom(addr, prefix.Bits()).String(), nil
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}
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// ParsedCIDR holds the parsed components of a CIDR notation string.
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type ParsedCIDR struct {
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PrefixMask string `json:"prefix_mask"`
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PrefixLen int `json:"prefix_len"`
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PrefixAddr string `json:"prefix_addr"`
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// BroadcastAddr is only set for IPv4 CIDRs.
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BroadcastAddr string `json:"broadcast_addr,omitempty"`
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}
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// ParseCIDR parses a CIDR notation string and returns its components:
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// prefix_mask (e.g. "255.255.255.0"), prefix_len (e.g. 24),
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// prefix_addr (e.g. "10.20.30.0"), and broadcast_addr (e.g. "10.20.30.255").
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// broadcast_addr is only set for IPv4 CIDRs.
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func ParseCIDR(s string) (*ParsedCIDR, error) {
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prefix, err := netip.ParsePrefix(s)
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if err != nil {
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return nil, err
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}
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+
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bits := prefix.Bits()
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addr := prefix.Addr()
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maskBytes := make([]byte, addr.BitLen()/8)
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for i := range bits / 8 {
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maskBytes[i] = 0xFF
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}
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if rem := bits % 8; rem > 0 {
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maskBytes[bits/8] = ^byte(0xFF >> rem)
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}
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netmask, _ := netip.AddrFromSlice(maskBytes)
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networkAddr := prefix.Masked().Addr()
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result := &ParsedCIDR{
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PrefixMask: netmask.String(),
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PrefixLen: bits,
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PrefixAddr: networkAddr.String(),
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}
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if addr.Is4() {
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broadcastBytes := networkAddr.AsSlice()
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for i := range broadcastBytes {
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broadcastBytes[i] |= ^maskBytes[i]
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}
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broadcastAddr, _ := netip.AddrFromSlice(broadcastBytes)
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result.BroadcastAddr = broadcastAddr.String()
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}
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return result, nil
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}
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// InCIDR reports whether an IP address is contained a CIDR subnet string.
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func InCIDR(ip, cidr cue.Value) (bool, error) {
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ipAddr := netGetIP(ip)
+12
pkg/net/pkg.go
+12
pkg/net/pkg.go
···
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}
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},
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}, {
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Name: "ParseCIDR",
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Params: []pkg.Param{
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{Kind: adt.StringKind},
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},
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Result: adt.StructKind,
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Func: func(c *pkg.CallCtxt) {
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s := c.String(0)
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if c.Do() {
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c.Ret, c.Err = ParseCIDR(s)
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}
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},
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}, {
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Name: "InCIDR",
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Params: []pkg.Param{
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{Kind: adt.TopKind},
+90
pkg/net/testdata/parsecidr.txtar
+90
pkg/net/testdata/parsecidr.txtar
···
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-- in.cue --
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import "net"
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// IPv4 tests
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t1: net.ParseCIDR("10.20.30.40/24")
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t2: net.ParseCIDR("192.168.1.0/24")
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t3: net.ParseCIDR("10.0.0.0/8")
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t4: net.ParseCIDR("172.16.0.0/16")
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t5: net.ParseCIDR("192.168.1.128/25")
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// IPv6 tests
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t6: net.ParseCIDR("2001:db8::/32")
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t7: net.ParseCIDR("fe80::/10")
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// Edge cases
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t8: net.ParseCIDR("0.0.0.0/0")
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t9: net.ParseCIDR("255.255.255.255/32")
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// Error cases
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t10: net.ParseCIDR("invalid")
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t11: net.ParseCIDR("192.168.1.1")
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-- out/net-v3 --
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Errors:
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t10: error in call to net.ParseCIDR: netip.ParsePrefix("invalid"): no '/':
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./in.cue:19:6
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t11: error in call to net.ParseCIDR: netip.ParsePrefix("192.168.1.1"): no '/':
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./in.cue:20:6
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Result:
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// IPv4 tests
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t1: {
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prefix_mask: "255.255.255.0"
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prefix_len: 24
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prefix_addr: "10.20.30.0"
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broadcast_addr: "10.20.30.255"
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}
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t2: {
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prefix_mask: "255.255.255.0"
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prefix_len: 24
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prefix_addr: "192.168.1.0"
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broadcast_addr: "192.168.1.255"
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}
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t3: {
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prefix_mask: "255.0.0.0"
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prefix_len: 8
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prefix_addr: "10.0.0.0"
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broadcast_addr: "10.255.255.255"
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}
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t4: {
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prefix_mask: "255.255.0.0"
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prefix_len: 16
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prefix_addr: "172.16.0.0"
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broadcast_addr: "172.16.255.255"
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}
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t5: {
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prefix_mask: "255.255.255.128"
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prefix_len: 25
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prefix_addr: "192.168.1.128"
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broadcast_addr: "192.168.1.255"
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}
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// IPv6 tests
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t6: {
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prefix_mask: "ffff:ffff::"
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prefix_len: 32
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prefix_addr: "2001:db8::"
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}
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t7: {
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prefix_mask: "ffc0::"
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prefix_len: 10
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prefix_addr: "fe80::"
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}
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// Edge cases
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t8: {
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prefix_mask: "0.0.0.0"
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prefix_len: 0
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prefix_addr: "0.0.0.0"
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broadcast_addr: "255.255.255.255"
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}
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t9: {
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prefix_mask: "255.255.255.255"
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prefix_len: 32
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prefix_addr: "255.255.255.255"
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broadcast_addr: "255.255.255.255"
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}
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// Error cases
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t10: _|_ // t10: error in call to net.ParseCIDR: netip.ParsePrefix("invalid"): no '/'
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t11: _|_ // t11: error in call to net.ParseCIDR: netip.ParsePrefix("192.168.1.1"): no '/'