-
Notifications
You must be signed in to change notification settings - Fork 9.4k
/
cidr.go
218 lines (192 loc) · 6.75 KB
/
cidr.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package funcs
import (
"fmt"
"math/big"
"github.com/apparentlymart/go-cidr/cidr"
"github.com/hashicorp/terraform/internal/ipaddr"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
"github.com/zclconf/go-cty/cty/gocty"
)
// CidrHostFunc contructs a function that calculates a full host IP address
// within a given IP network address prefix.
var CidrHostFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "prefix",
Type: cty.String,
},
{
Name: "hostnum",
Type: cty.Number,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var hostNum *big.Int
if err := gocty.FromCtyValue(args[1], &hostNum); err != nil {
return cty.UnknownVal(cty.String), err
}
_, network, err := ipaddr.ParseCIDR(args[0].AsString())
if err != nil {
return cty.UnknownVal(cty.String), fmt.Errorf("invalid CIDR expression: %s", err)
}
ip, err := cidr.HostBig(network, hostNum)
if err != nil {
return cty.UnknownVal(cty.String), err
}
return cty.StringVal(ip.String()), nil
},
})
// CidrNetmaskFunc contructs a function that converts an IPv4 address prefix given
// in CIDR notation into a subnet mask address.
var CidrNetmaskFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "prefix",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
_, network, err := ipaddr.ParseCIDR(args[0].AsString())
if err != nil {
return cty.UnknownVal(cty.String), fmt.Errorf("invalid CIDR expression: %s", err)
}
if network.IP.To4() == nil {
return cty.UnknownVal(cty.String), fmt.Errorf("IPv6 addresses cannot have a netmask: %s", args[0].AsString())
}
return cty.StringVal(ipaddr.IP(network.Mask).String()), nil
},
})
// CidrSubnetFunc contructs a function that calculates a subnet address within
// a given IP network address prefix.
var CidrSubnetFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "prefix",
Type: cty.String,
},
{
Name: "newbits",
Type: cty.Number,
},
{
Name: "netnum",
Type: cty.Number,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var newbits int
if err := gocty.FromCtyValue(args[1], &newbits); err != nil {
return cty.UnknownVal(cty.String), err
}
var netnum *big.Int
if err := gocty.FromCtyValue(args[2], &netnum); err != nil {
return cty.UnknownVal(cty.String), err
}
_, network, err := ipaddr.ParseCIDR(args[0].AsString())
if err != nil {
return cty.UnknownVal(cty.String), fmt.Errorf("invalid CIDR expression: %s", err)
}
newNetwork, err := cidr.SubnetBig(network, newbits, netnum)
if err != nil {
return cty.UnknownVal(cty.String), err
}
return cty.StringVal(newNetwork.String()), nil
},
})
// CidrSubnetsFunc is similar to CidrSubnetFunc but calculates many consecutive
// subnet addresses at once, rather than just a single subnet extension.
var CidrSubnetsFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "prefix",
Type: cty.String,
},
},
VarParam: &function.Parameter{
Name: "newbits",
Type: cty.Number,
},
Type: function.StaticReturnType(cty.List(cty.String)),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
_, network, err := ipaddr.ParseCIDR(args[0].AsString())
if err != nil {
return cty.UnknownVal(cty.String), function.NewArgErrorf(0, "invalid CIDR expression: %s", err)
}
startPrefixLen, _ := network.Mask.Size()
prefixLengthArgs := args[1:]
if len(prefixLengthArgs) == 0 {
return cty.ListValEmpty(cty.String), nil
}
var firstLength int
if err := gocty.FromCtyValue(prefixLengthArgs[0], &firstLength); err != nil {
return cty.UnknownVal(cty.String), function.NewArgError(1, err)
}
firstLength += startPrefixLen
retVals := make([]cty.Value, len(prefixLengthArgs))
current, _ := cidr.PreviousSubnet(network, firstLength)
for i, lengthArg := range prefixLengthArgs {
var length int
if err := gocty.FromCtyValue(lengthArg, &length); err != nil {
return cty.UnknownVal(cty.String), function.NewArgError(i+1, err)
}
if length < 1 {
return cty.UnknownVal(cty.String), function.NewArgErrorf(i+1, "must extend prefix by at least one bit")
}
// For portability with 32-bit systems where the subnet number
// will be a 32-bit int, we only allow extension of 32 bits in
// one call even if we're running on a 64-bit machine.
// (Of course, this is significant only for IPv6.)
if length > 32 {
return cty.UnknownVal(cty.String), function.NewArgErrorf(i+1, "may not extend prefix by more than 32 bits")
}
length += startPrefixLen
if length > (len(network.IP) * 8) {
protocol := "IP"
switch len(network.IP) * 8 {
case 32:
protocol = "IPv4"
case 128:
protocol = "IPv6"
}
return cty.UnknownVal(cty.String), function.NewArgErrorf(i+1, "would extend prefix to %d bits, which is too long for an %s address", length, protocol)
}
next, rollover := cidr.NextSubnet(current, length)
if rollover || !network.Contains(next.IP) {
// If we run out of suffix bits in the base CIDR prefix then
// NextSubnet will start incrementing the prefix bits, which
// we don't allow because it would then allocate addresses
// outside of the caller's given prefix.
return cty.UnknownVal(cty.String), function.NewArgErrorf(i+1, "not enough remaining address space for a subnet with a prefix of %d bits after %s", length, current.String())
}
current = next
retVals[i] = cty.StringVal(current.String())
}
return cty.ListVal(retVals), nil
},
})
// CidrHost calculates a full host IP address within a given IP network address prefix.
func CidrHost(prefix, hostnum cty.Value) (cty.Value, error) {
return CidrHostFunc.Call([]cty.Value{prefix, hostnum})
}
// CidrNetmask converts an IPv4 address prefix given in CIDR notation into a subnet mask address.
func CidrNetmask(prefix cty.Value) (cty.Value, error) {
return CidrNetmaskFunc.Call([]cty.Value{prefix})
}
// CidrSubnet calculates a subnet address within a given IP network address prefix.
func CidrSubnet(prefix, newbits, netnum cty.Value) (cty.Value, error) {
return CidrSubnetFunc.Call([]cty.Value{prefix, newbits, netnum})
}
// CidrSubnets calculates a sequence of consecutive subnet prefixes that may
// be of different prefix lengths under a common base prefix.
func CidrSubnets(prefix cty.Value, newbits ...cty.Value) (cty.Value, error) {
args := make([]cty.Value, len(newbits)+1)
args[0] = prefix
copy(args[1:], newbits)
return CidrSubnetsFunc.Call(args)
}