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v0.2.1

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FIXED:
* host splitter wasn't working quite correctly; this has been fixed.
This commit is contained in:
brent saner 2025-04-06 18:26:18 -04:00
parent fd344f3b8e
commit 3c1bc832c0
Signed by: bts
GPG Key ID: 8C004C2F93481F6B
7 changed files with 221 additions and 90 deletions
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2
TODO
View File

@ -3,5 +3,3 @@
- when checking/rendering reserved networks, currently the footnotes aren't returned.
-- netsplit.IANARegistryFootnote
-- encapsulated in the IANARegistry.Footnotes

- split-hosts returns the entire original subnet as an unallocated subnet if hosts exceed the number of assignable addrs.

18
cmd/subnetter/args.go
View File

@ -2,8 +2,8 @@ package main

type Args struct {
Version verArgs `command:"version" alias:"v" description:"Show version information." validate:"omitempty"`
SplitCIDR SplitCIDRArgs `command:"split-cidr" alias:"se" description:"Split a network into as many equal subnets of prefix size N as possible." validate:"omitempty"`
SplitHost SplitHostArgs `command:"split-hosts" alias:"sh" description:"Split a network into N total number of hosts *per subnet* as cleanly/evenly as possible. (VERY easy to run out of memory for IPv6 prefixes; be sure to specify very small network!)" validate:"omitempty"`
SplitCIDR SplitCIDRArgs `command:"split-cidr" alias:"sc" description:"Split a network into as many equal subnets of prefix size N as possible." validate:"omitempty"`
SplitHost SplitHostArgs `command:"split-hosts" alias:"sh" description:"Split a network into N total number of hosts *per subnet* as cleanly/evenly as possible." validate:"omitempty"`
SplitSubnets SplitSubnetArgs `command:"split-nets" alias:"sn" description:"Split a network into N number of subnets as cleanly as possible." validate:"omitempty"`
VLSM VLSMArgs `command:"split-vlsm" alias:"sv" alias:"vlsm" description:"Use VLSM (Variable-Length Subnet Masks) to split a network into differently sized subnets." validate:"omitempty"`
ExplicitNetwork XNetArgs `command:"net" alias:"xn" alias:"net" description:"Print information about an explicit network address." validate:"omitempty"`
@ -36,8 +36,8 @@ type common struct {

type reservedArgs struct {
NoRecursive bool `short:"u" long:"no-recursive" description:"Don't show reservations that are children subnets of the subnet(s). Only if -f/--format=pretty, always false for other formats."`
NoRevRecursive bool `short:"U" long:"no-rev-recursive" description:"Don't show reservations that are parents of the subnet(s). Only if -f/--format=pretty, always false for other formats."`
NoPrivate bool `short:"e" long:"no-private" description:"Consider private subnets of the subnet(s) to be reserved. If you are subnetting private address space, you probably want to leave this disabled. Only if -f/--format=pretty, always true otherwise."`
NoRevRecursive bool `short:"U" long:"no-rev-recursive" description:"Don't show reservations that are parents of the subnet(s) -- you almost definitely don't want to suppress this. Only if -f/--format=pretty, always false for other formats."`
NoPrivate bool `short:"e" long:"no-private" description:"Consider private subnets to be reserved. If you are subnetting private address space, you probably want to leave this disabled. Only if -f/--format=pretty, always true otherwise."`
}

type splitArgs struct {
@ -53,8 +53,8 @@ type NNetArgs struct {
Verbose bool `short:"v" long:"verbose" description:"Be verbose (more ideal for logging)."`
NoV6Check bool `short:"6" long:"no-v6" description:"If specified, do not indicate if the subnetting is IPv6 only (true) or not (false; dual-stack/IPv4 supported)."`
Sizes struct {
SubnetSize uint8 `required:"1" validate:"required,le=128,gtefield=NetworkSize"`
NetworkSize uint8 `required:"1" validate:"required,le=128,ltefield=SubnetSize"`
SubnetSize uint8 `positional-arg-name:"<subnet prefix>" required:"1" validate:"lte=128,gtefield=NetworkSize"`
NetworkSize uint8 `positional-arg-name:"<parent prefix>" required:"1" validate:"lte=128,ltefield=SubnetSize"`
} `positional-args:"yes" required:"2" validate:"required"`
}

@ -69,8 +69,10 @@ type SplitCIDRArgs struct {
}

type SplitHostArgs struct {
Strict bool `short:"t" long:"strict" description:"If specified, an error will occur if the number of hosts/assignable addresses in a subnet is not exactly -n/--num-hosts."`
Hosts uint `short:"n" long:"num-hosts" required:"true" description:"Number of hosts (usable addresses) per subnet." validate:"required"`
InclNetAddr bool `short:"N" long:"incl-net" description:"If specified, -n/--num-hosts is interpreted to include the network address in the count."`
InclBcastAddr bool `short:"B" long:"incl-bcast" description:"If specified, -n/--num-hosts is interpreted to include the broadcast/reserved broadcast address in the count."`
Strict bool `short:"t" long:"strict" description:"If specified, an error will occur if the number of hosts/assignable addresses in a subnet is not exactly -n/--num-hosts."`
Hosts uint `short:"n" long:"num-hosts" required:"true" description:"Number of hosts (usable addresses) per subnet." validate:"required"`
splitArgs
}


10
cmd/subnetter/funcs.go
View File

@ -401,7 +401,9 @@ func printNets(orig *netip.Prefix, origNet *net.IPNet, nets []*netip.Prefix, rem

// Remaining
if !args.SuppressRemaining {
if verb >= 1 {
if verb <= 0 {
fmt.Println("#")
} else {
fmt.Println()
fmt.Println(sectSep1)
fmt.Println("Remaining/Left Over/Unallocated:")
@ -660,7 +662,7 @@ func printSplitErr(e *netsplit.SplitErr) {
os.Stderr.WriteString("\n!! ERROR !!!\n")

os.Stderr.WriteString("\t" + e.Wrapped.Error() + "\n")
os.Stderr.WriteString("\nnetwork Iteration Details\n(when error was encountered):\n\n")
os.Stderr.WriteString("\nNetwork Iteration Details\n(when error was encountered):\n\n")
if e.Nets == nil {
os.Stderr.WriteString("Nets:\t\t\t(N/A)\n")
} else {
@ -669,7 +671,7 @@ func printSplitErr(e *netsplit.SplitErr) {
fmt.Fprintf(os.Stderr, "\t%s\n", n.String())
}
}
if e.Remaining == nil {
if e.Remaining == nil || e.Remaining.Prefixes() == nil || len(e.Remaining.Prefixes()) == 0 {
os.Stderr.WriteString("Remaining:\t\t(N/A)\n")
} else {
os.Stderr.WriteString("Remaining:\n")
@ -678,7 +680,7 @@ func printSplitErr(e *netsplit.SplitErr) {
}
}
if e.LastSubnet == nil {
os.Stderr.WriteString("Last Subnet:\t\t(N/A)")
os.Stderr.WriteString("Last Subnet:\t\t(N/A)\n")
} else {
fmt.Fprintf(os.Stderr, "Last Subnet:\t\t%s\n", e.LastSubnet.String())
}

23
cmd/subnetter/main.go
View File

@ -69,6 +69,9 @@ func main() {
return
}
case "net":
if err = validate.Struct(args.ExplicitNetwork.Network.Network); err != nil {
log.Panicln(err)
}
if origPfx, err = netip.ParsePrefix(args.ExplicitNetwork.Network.Network); err != nil {
log.Panicln(err)
}
@ -82,6 +85,9 @@ func main() {
}
return
case "num-nets":
if err = validate.Struct(args.NumNets); err != nil {
log.Panicln(err)
}
if numNets, v6Only, err = netsplit.NumNets(
args.NumNets.Sizes.SubnetSize,
args.NumNets.Sizes.NetworkSize,
@ -103,6 +109,9 @@ func main() {
}
return
case "reserved":
if err = validate.Struct(args.Check); err != nil {
log.Panicln(err)
}
if origPfx, err = netip.ParsePrefix(args.Check.Network.Network); err != nil {
log.Panicln(err)
}
@ -123,6 +132,9 @@ func main() {
}
return
case "table":
if err = validate.Struct(args.Table); err != nil {
log.Panicln(err)
}
// Account for a weird redundant CLI condition.
if args.Table.NoIpv4 && args.Table.NoIpv6 {
args.Table.NoIpv6 = false
@ -135,6 +147,9 @@ func main() {
os.Stdout.Write(buf.Bytes())
return
case "parse":
if err = validate.Struct(args.Parse); err != nil {
log.Panicln(err)
}
if strings.TrimSpace(args.Parse.InFile) == "-" {
buf = new(bytes.Buffer)
if _, err = io.Copy(buf, os.Stdin); err != nil {
@ -186,9 +201,11 @@ func main() {
}
cmnArgs = args.SplitHost.common
splitter = &netsplit.HostSplitter{
NumberHosts: args.SplitHost.Hosts,
Strict: args.SplitHost.Strict,
BaseSplitter: new(netsplit.BaseSplitter),
InclNetAddr: args.SplitHost.InclNetAddr,
InclBcastAddr: args.SplitHost.InclBcastAddr,
NumberHosts: args.SplitHost.Hosts,
Strict: args.SplitHost.Strict,
BaseSplitter: new(netsplit.BaseSplitter),
}
noStrict = !args.SplitHost.Strict
strictErr = netsplit.ErrBadNumHosts

153
netsplit/funcs.go
View File

@ -193,25 +193,26 @@ func CheckReserved(nets []*netip.Prefix, revRecursive, recursive, excludePrivate
reservations = make(map[netip.Prefix]*IANAAddrNetResRecord)
}
reservations[*n] = res
if !revRecursive && !recursive {
continue
}
for p, r := range reserved {
// This... *should* be safe? I don't think any reservations overlap.
// Anyways, revRecursive works because n.Addr() returns the network address, which should be the canonical boundary.
// recursive works for the same reason, just the other end.
// Math!
if revRecursive && p.Contains(n.Addr()) {
if reservations == nil {
reservations = make(map[netip.Prefix]*IANAAddrNetResRecord)
}
reservations[p] = r
} else if recursive && n.Contains(p.Addr()) {
if reservations == nil {
reservations = make(map[netip.Prefix]*IANAAddrNetResRecord)
}
reservations[p] = r
}
if !revRecursive && !recursive {
continue
}
for p, r := range reserved {
// This... *should* be safe? I don't think any reservations overlap.
// Anyways, revRecursive works because n.Addr() returns the network address, which should be the canonical boundary.
// recursive works for the same reason, just the other end.
// Math!
if revRecursive && p.Contains(n.Addr()) {
if reservations == nil {
reservations = make(map[netip.Prefix]*IANAAddrNetResRecord)
}
reservations[p] = r
}
if recursive && n.Bits() < p.Bits() && n.Contains(p.Addr()) {
if reservations == nil {
reservations = make(map[netip.Prefix]*IANAAddrNetResRecord)
}
reservations[p] = r
}
}
}
@ -223,7 +224,7 @@ func CheckReserved(nets []*netip.Prefix, revRecursive, recursive, excludePrivate
func Contain(origPfx *netip.Prefix, nets []*netip.Prefix, remaining *netipx.IPSet, splitter NetSplitter) (s *StructuredResults, err error) {

var rem []netip.Prefix
var reserved map[netip.Prefix]*IANAAddrNetResRecord
// var reserved map[netip.Prefix]*IANAAddrNetResRecord
var sr = StructuredResults{
Original: origPfx,
}
@ -276,19 +277,21 @@ func Contain(origPfx *netip.Prefix, nets []*netip.Prefix, remaining *netipx.IPSe
}
}

if nets != nil {
if reserved, err = CheckReserved(nets, true, true, false); err != nil {
return
}
if reserved != nil && len(reserved) > 0 {
s.Reservations = make([]*IANAAddrNetResRecord, len(reserved))
idx := 0
for _, r := range reserved {
s.Reservations[idx] = r
idx++
/*
if nets != nil {
if reserved, err = CheckReserved(nets, true, true, false); err != nil {
return
}
if reserved != nil && len(reserved) > 0 {
s.Reservations = make([]*IANAAddrNetResRecord, len(reserved))
idx := 0
for _, r := range reserved {
s.Reservations[idx] = r
idx++
}
}
}
}
*/

s = &sr

@ -377,27 +380,105 @@ func MaskInvert(mask net.IPMask) (inverted net.IPMask) {
return
}

/*
NumAddrsIn returns the number of addresses in a given prefix length
and inet family.

If isIpv6 is false, it is assumed to be IPv4 (...duh).

inclNet and inclBcast have the same meanings as in NumAddrsNet and NumAddrsPfx.

Note that for the single-host prefix (/32 for IPv4, /128 for IPv6), numAddrs will *always* be 1.
For point-to-point prefix (IPv4 /31, IPv6 /127), numAddrs will *ALWAYS* be 2.
*/
func NumAddrsIn(prefixLen uint8, isIpv6, inclNet, inclBcast bool) (numAddrs *big.Int, err error) {

var numBits uint
var numRemoved int64
var maxBitLen uint8 = maxBitsv4

if isIpv6 {
maxBitLen = maxBitsv6
}
if prefixLen > maxBitLen {
err = ErrBadPrefixLen
return
}
if prefixLen == maxBitLen {
numAddrs = big.NewInt(1)
return
}
if (prefixLen + 1) == maxBitLen {
numAddrs = big.NewInt(2)
return
}

numBits = uint(maxBitLen - prefixLen)

numAddrs = new(big.Int).Lsh(big.NewInt(1), numBits)

if !inclNet {
numRemoved++
}
if !inclBcast {
numRemoved++
}
if numRemoved > 0 {
_ = numAddrs.Sub(numAddrs, big.NewInt(numRemoved))
}

return
}

/*
NumAddrsNet returns the number of IP addresses in a net.IPNet.

# The network address is included in the count if inclNet is true, otherwise it is excluded
The network address is included in the count if inclNet is true, otherwise it is excluded.

Only assignable addresses ("hosts") are considered if hostsOnly is true,
otherwise all addresses are counted (depending on inclNet).
The broadcast (or reserved broadcast, in the case of IPv6) address will be included in
the count if inclBcast is true, otherwise it is excluded.

numAddrs will be nil if pfx is nil or invalid.
*/
func NumAddrsNet(pfx *net.IPNet, inclNet, hostsOnly bool) (numAddrs *big.Int) {
func NumAddrsNet(pfx *net.IPNet, inclNet, inclBcast bool) (numAddrs *big.Int) {

var nPfx netip.Prefix
var ok bool

if pfx == nil {
return
}
if nPfx, ok = netipx.FromStdIPNet(pfx); !ok {
return
}

// TODO
numAddrs = NumAddrsPfx(nPfx, inclNet, inclBcast)

return
}

// NumAddrsPfx is the exact same as NumAddrsNet but for a net/netip.Prefix instead.
// TODO
func NumAddrsPfx(pfx netip.Prefix, inclNet, inclBcast bool) (numAddrs *big.Int) {

var numBits uint
var numRemoved int64

numBits = uint(pfx.Addr().BitLen() - pfx.Bits())

numAddrs = new(big.Int).Lsh(big.NewInt(1), numBits)

if !inclNet {
numRemoved++
}
if !inclBcast {
numRemoved++
}
if numRemoved > 0 {
_ = numAddrs.Sub(numAddrs, big.NewInt(numRemoved))
}

return
}

/*
NumNets returns the number of times prefix size subnet fits into prefix size network.

97
netsplit/funcs_hostsplitter.go
View File

@ -1,12 +1,9 @@
package netsplit

import (
"fmt"
"math/big"
"net"
"net/netip"

"github.com/projectdiscovery/mapcidr"
"go4.org/netipx"
)

@ -16,54 +13,84 @@ This strategy attempts to split the network into subnets of equal number of host

remaining may or may not be nil depending on if the number of hosts can fit cleanly within equal network sizes on boundaries.

An ErrBadNumHosts will be returned if the number of hosts does not match the *addressable* range in a prefix.
An ErrBadNumHosts will be returned if the number of hosts does not match the *exact* number of addresses per spec in a prefix.
*/
func (h *HostSplitter) Split() (nets []*netip.Prefix, remaining *netipx.IPSet, err error) {

var pfx netip.Prefix
var tgt *big.Int
var splitCidr int
var hosts *big.Int
var sub netip.Prefix
var subPtr *netip.Prefix
var split []*net.IPNet
var ipsb *netipx.IPSetBuilder = new(netipx.IPSetBuilder)
var found bool
var cs *CIDRSplitter

if h == nil || h.NumberHosts == 0 || h.BaseSplitter == nil || h.network == nil {
return
}

if split, err = mapcidr.SplitIPNetByNumber(h.network, int(h.NumberHosts)); err != nil {
pfx, _ = netipx.FromStdIPNet(h.network)
tgt = new(big.Int)
tgt.SetUint64(uint64(h.NumberHosts))

if NumAddrsPfx(pfx, h.InclNetAddr, h.InclBcastAddr).Cmp(tgt) < 0 {
// The number of hosts per-subnet exceeds the number of addresses in the specified network.
err = ErrNoNetSpace
return
}
/*
Iterate up through prefix lengths for the inet family's maximum length, getting larger and larger,
until we reach the first prefix that can contain tgt.
If we reach h.network.Bits(), we are forced to use that.
(Any case otherwise should be handled by the above checks.)
*/
for splitCidr = pfx.Addr().BitLen(); splitCidr >= pfx.Bits(); splitCidr-- {
if hosts, err = NumAddrsIn(uint8(splitCidr), pfx.Addr().Is6(), h.InclNetAddr, h.InclBcastAddr); err != nil {
return
}
if hosts.Cmp(tgt) >= 0 {
found = true
break
}
}
if !found {
// Pragmatically, we should never be able to get to this code.
err = ErrNoNetSpace
return
}

fmt.Println(split)

tgt = big.NewInt(0)
tgt.SetUint64(uint64(h.NumberHosts))

nets = make([]*netip.Prefix, len(split))
for idx, n := range split {
sub, _ = netipx.FromStdIPNet(n)
hosts = mapcidr.CountIPsInCIDR(false, false, n)
if hosts == nil || tgt.Cmp(hosts) != 0 {
err = &SplitErr{
Wrapped: ErrBadNumHosts,
Nets: nets,
Remaining: remaining,
LastSubnet: &sub,
RequestedPrefixLen: uint8(sub.Bits()),
}
ipsb.AddPrefix(sub)
} else {
subPtr = new(netip.Prefix)
*subPtr = sub
nets = append(nets, subPtr)
// Now that we have an appropriate prefix length for splitting, we can offload a huge portion of that to a CIDRSplitter.
cs = &CIDRSplitter{
PrefixLength: uint8(splitCidr),
BaseSplitter: h.BaseSplitter,
}
if nets, remaining, err = cs.Split(); err != nil {
return
}
// If strict mode is enabled, we then need to match the number of hosts exactly in the subnet.
if !h.Strict {
return
}
// First off, if remaining is not nil/empty, that immediately fails strict.
if remaining != nil && remaining.Prefixes() != nil && len(remaining.Prefixes()) != 0 {
err = &SplitErr{
Wrapped: ErrBadNumHosts,
Nets: nets,
Remaining: remaining,
LastSubnet: nil,
RequestedPrefixLen: uint8(splitCidr),
}

nets[idx] = new(netip.Prefix)
*nets[idx] = sub
return
}

if remaining, err = ipsb.IPSet(); err != nil {
// Then we check the cidr we split on, and check its number of hosts.
if hosts.Cmp(tgt) != 0 {
err = &SplitErr{
Wrapped: ErrBadNumHosts,
Nets: nets,
Remaining: remaining,
LastSubnet: nil,
RequestedPrefixLen: uint8(splitCidr),
}
return
}


8
netsplit/types.go
View File

@ -51,6 +51,10 @@ It attempts to evenly distribute addresses amoungs subnets.
type HostSplitter struct {
// NumberHosts is the number of hosts to be placed in each subnet to split out.
NumberHosts uint `json:"hosts" xml:"hosts,attr" yaml:"Number of Hosts Per Subnet"`
// InclNetAddr, if true, specifies that NumberHosts includes the network address.
InclNetAddr bool `json:"net_addr" xml:"netAddr,attr,omitempty" yaml:"Network Address Included,omitempty"`
// InclBcastAddr, if true, specifies that NumberHosts includes the broadcast address.
InclBcastAddr bool `json:"bcast_addr" xml:"bcast,attr,omitempty" yaml:"Broadcast Address Included,omitempty"`
// Strict, if true, will return an error from Split if the network cannot split into subnets of NumberHosts-addressable networks exactly.
Strict bool `json:"strict" xml:"strict,attr,omitempty" yaml:"Strictly Equal Hosts Per Subnet"`
*BaseSplitter `json:"net" xml:"net,omitempty" yaml:"network,omitempty"`
@ -78,14 +82,14 @@ type VLSMSplitter struct {
(ascending order) instead of larger networks/smaller prefixes (descending order).
You almost assuredly do not want to do this.
*/
Ascending bool
Ascending bool `json:"asc,omitempty" xml:"asc,attr,omitempty" yaml:"Ascending Order,omitempty"`
/*
Explicit, if true, will ignore Ascending completely and split in the explicit order of PrefixLengths.

This has the potential to be *extremely* wasteful of addressing space as the resulting blocks are
VERY unoptimized.
*/
Explicit bool
Explicit bool `json:"explicit,omitempty" xml:"explicit,attr,omitempty" yaml:"Explicit Ordering,omitempty"`
// PrefixLengths contains the prefix lengths of each subnet to split out from the network.
PrefixLengths []uint8 `json:"prefixes" xml:"prefixes>prefix" yaml:"Prefix Lengths"`
*BaseSplitter `json:"net" xml:"net,omitempty" yaml:"network,omitempty"`