v0.2.0

ADDED: * num-nets subcommand' this is MUCH much faster than actually splitting if you're trying to figure out how many times a given subnet fits into a network.
update TODO with bug to look into
2025-04-06 01:31:51 -04:00 · 2025-04-04 14:33:39 -04:00 · 2025-04-04 14:29:07 -04:00 · 2025-04-04 11:53:55 -04:00 · 2025-04-03 18:35:35 -04:00 · 2025-03-10 10:07:51 -04:00
20 changed files with 445 additions and 68 deletions
--- a/README.adoc
+++ b/README.adoc
@@ -50,7 +50,7 @@ A tool to assist in design of segregate/segment/split/subnet networks.
 **** If the `XDG_CACHE_HOME` environment variable is not present...
 ***** On macOS, an explicit fallback of `~/Library/Caches/subnetter/` will be used. (To my knowledge/understanding, this is the standard user cache directory and cannot be changed.) This usually evaluates to `/Users/<username>/Library/Caches/subnetter/`.
 ***** On all others, an explicit fallback of `~/.cache/subnetter` will be used.
-****** On most non-macOS \*NIX-like systems , this is usually `/home/<username>/.cache/subetter/`, provided normal user homes. On http://p9f.org/[Plan9^] platforms (e.g. https://9p.io/plan9/index.html[Plan 9 4th Ed.^], https://9front.org/[9front^], http://9legacy.org/[9legacy^]), the `/env/home` environment variable (`$home`) will be used, the `./lib/` subdirectory under there (which typically/should already exist) will be appended to it, and that appended with `./cache/subnetter/` (this usually evaluates to `/usr/<username>/lib/cache/subnetter/`).
+****** On most non-macOS/*NIX-like systems , this is usually `/home/<username>/.cache/subetter/`, provided normal user homes. On http://p9f.org/[Plan9^] platforms (e.g. https://9p.io/plan9/index.html[Plan 9 4th Ed.^], https://9front.org/[9front^], http://9legacy.org/[9legacy^]), the `/env/home` environment variable (`$home`) will be used, the `./lib/` subdirectory under there (which typically/should already exist) will be appended to it, and that appended with `./cache/subnetter/` (this usually evaluates to `/usr/<username>/lib/cache/subnetter/`).
 *** For Windows systems...
 **** If https://learn.microsoft.com/en-us/windows/win32/shell/knownfolderid#constants[the `LOCALAPPDATA` environment variable^] is present, it will be `%LOCALAPPDATA%\Cache\subnetter\` (or `${env:LOCALAPPDATA}\Cache\subnetter\` in Powershell syntax). This usually evaluates to `C:\Users\<username>\AppData\Local\Cache\subnetter\`.

@@ -61,3 +61,5 @@ This program in general draws inspiration from `ipcalc` (http://jodies.de/ipcalc
 The `table` subcommand is inspired by `iptab` from https://metacpan.org/pod/Net::IP[Perl Net-IP^].

 Additional notes for certain contexts are primarily taken from https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing[the Wikipedia article on _Classless Inter-Domain Routing_^] (as of _Jan 28, 2025_).
+
+Reservations are pulled/cached directly from the IANA registries (https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml[IPv4^], https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml[IPv6^]).
--- a/6
+++ b/6
@@ -1 +1,7 @@
 - add table rendering for reserved networks?
+
+- 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.
--- a/cmd/subnetter/_tpl/check.tpl
+++ b/cmd/subnetter/_tpl/check.tpl
@@ -1,2 +1,2 @@
-{{- /*gotype: subnetter/cmd/subnetter.ReservedResults*/ -}}
+{{- /*gotype: r00t2.io/subnetter/cmd/subnetter.ReservedResults*/ -}}
 {{- $opts := . -}}
--- a/cmd/subnetter/_tpl/table.tpl
+++ b/cmd/subnetter/_tpl/table.tpl
@@ -1,4 +1,4 @@
-{{- /*gotype: subnetter/cmd/subnetter.TableArgs*/ -}}
+{{- /*gotype: r00t2.io/subnetter/cmd/subnetter.TableArgs*/ -}}
 {{- $opts := . -}}
 {{- $numRows := 0 -}}
 {{- if not $opts.NoIpv4 }}
--- a/cmd/subnetter/args.go
+++ b/cmd/subnetter/args.go
@@ -5,8 +5,9 @@ type Args struct {
 	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"`
 	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:"vlsm" alias:"sv" description:"Use VLSM (Variable-Length Subnet Masks) to split a network into differently sized subnets." validate:"omitempty"`
-	ExplicitNetwork XNetArgs        `command:"net" alias:"xn" description:"Print information about an explicit network address." 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"`
+	NumNets         NNetArgs        `command:"num-nets" alias:"nn" alias:"nets" description:"Return the number of subnets of a given size that can fit into a given network size. This is MUCH, MUCH FASTER than splitting (if you do not need addressing)." validate:"omitempty"`
 	Parse           ParseArgs       `command:"parse" alias:"p" alias:"read" alias:"convert" description:"Parse/convert output from a previous subnetter run." validate:"omitempty"`
 	Table           TableArgs       `command:"table" alias:"t" alias:"tab" alias:"tbl" description:"Show prefix summaries (by default both IPv4 and IPv6)." validate:"omitempty"`
 	Check           CheckArgs       `command:"reserved" alias:"r" description:"Check if a subnet is reserved per IANA/RFC." validate:"omitempty"`
@@ -16,7 +17,7 @@ type verArgs struct {
 	DetailVersion bool `short:"V" long:"detail" description:"Print detailed version info and exit."`
 }

-type common struct {
+type commonBase struct {
 	cacheArgs
 	SuppressRemaining bool   `short:"r" long:"no-remaining" description:"Don't show leftover/unallocated/remaining space."`
 	Plain             bool   `short:"p" long:"plain" description:"Show plain output instead of unicode (only used if -f/--format=pretty)."`
@@ -26,6 +27,10 @@ type common struct {
 	AllowReserved     bool   `short:"R" long:"allow-reserved" description:"If specified, do not warn about reserved IP addresses/networks."`
 	reservedArgs
 	AllowHostNet bool `short:"H" long:"allow-host" description:"If specified, do not warn about host bits. Host bits are always removed for subnetting (as otherwise there would be errors); this is only used only for output."`
+}
+
+type common struct {
+	commonBase
 	Network Net `positional-args:"yes" required:"true" description:"The network/parent prefix to operate on." validate:"required"`
 }

@@ -44,8 +49,17 @@ type cacheArgs struct {
 	DoResCache bool   `short:"c" long:"cache-reservations" env:"SBNTR_RSVCACHE" description:"Enable caching/cache lookup for reservation data."`
 }

+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"`
+	} `positional-args:"yes" required:"2" validate:"required"`
+}
+
 type ParseArgs struct {
-	splitArgs
+	commonBase
 	InFile string `short:"i" long:"input" default:"-" description:"Input file to parse. Default is '-' (for STDIN)." required:"true" validate:"required,filepath|eq=-"`
 }

@@ -89,7 +103,10 @@ type XNetArgs struct {

 type VLSMArgs struct {
 	Asc      bool `short:"A" long:"ascending" description:"If specified, place smaller networks (larger prefixes) at the beginning. You almost assuredly do not want to do this."`
-	Sizes []uint8 `short:"s" long:"size" required:"true" description:"Prefix lengths. May be specified multiple times." validate:"required"`
+	Explicit bool `short:"O" long:"explicit-order" description:"If specified, ignore -A/--ascending and do no reordering of prefix sizes whatsoever, instead using the order given. This is EXTREMELY suboptimal and can lead to drastic addressing waste."`
+	// Custom type for now; see https://github.com/jessevdk/go-flags/issues/245
+	// Sizes    []uint8 `short:"s" long:"size" required:"true" description:"Prefix lengths. May be specified multiple times." validate:"required"`
+	Sizes []vlsmSize `short:"s" long:"size" required:"true" description:"Prefix lengths. May be specified multiple times or as a comma-delimited list." validate:"required"`
 	splitArgs
 }

--- a/cmd/subnetter/errs.go
+++ b/cmd/subnetter/errs.go
@@ -5,5 +5,6 @@ import (
 )

 var (
+	ErrBadFmt error = errors.New("unknown output format")
 	errBadNet error = errors.New("bad inet/addr family/version")
 )
--- a/cmd/subnetter/funcs.go
+++ b/cmd/subnetter/funcs.go
@@ -10,15 +10,15 @@ import (
 	"net"
 	"net/netip"
 	"os"
-	`sort`
+	"sort"
 	"strings"
 	"time"

 	"github.com/goccy/go-yaml"
 	"github.com/projectdiscovery/mapcidr"
 	"go4.org/netipx"
-	"subnetter/netsplit"
-	`subnetter/version`
+	"r00t2.io/subnetter/netsplit"
+	"r00t2.io/subnetter/version"
 )

 func printHostPrefix(label string, pfx *netip.Prefix, verb, indent int, indentStr string) (out string) {
@@ -236,7 +236,9 @@ func printNets(orig *netip.Prefix, origNet *net.IPNet, nets []*netip.Prefix, rem

 	if args == nil {
 		args = &common{
+			commonBase: commonBase{
 				Separator: "\n",
+			},
 		}
 	}
 	fmts = sectFmts[args.Plain]
@@ -471,7 +473,180 @@ func printNets(orig *netip.Prefix, origNet *net.IPNet, nets []*netip.Prefix, rem
 	return
 }

-func printReserved(nets []*netip.Prefix, remaining *netipx.IPSet, args *common) (err error) {
+func printReserved(records map[netip.Prefix]*netsplit.IANAAddrNetResRecord, origNet netip.Prefix, plain bool, fmtType string) (err error) {
+
+	var b []byte
+	var idx int
+	var pfx netip.Prefix
+	var rec *netsplit.IANAAddrNetResRecord
+	var sortedKeys []netip.Prefix
+	var sb = new(strings.Builder)
+
+	switch fmtType {
+	case "json":
+		if b, err = json.MarshalIndent(records, "", "  "); err != nil {
+			return
+		}
+		fmt.Println(string(b))
+		return
+	case "xml":
+		if b, err = xml.MarshalIndent(records, "", "  "); err != nil {
+			return
+		}
+		fmt.Println(string(b))
+		return
+	case "yml", "yaml":
+		if b, err = yaml.Marshal(records); err != nil {
+			return
+		}
+		fmt.Println(string(b))
+		return
+	}
+
+	if fmtType != "pretty" {
+		err = ErrBadFmt
+		return
+	}
+
+	if records == nil || len(records) == 0 {
+		fmt.Println("No IANA/IETF/RFC-reserved subnet(s) found.")
+		return
+	}
+
+	sortedKeys = make([]netip.Prefix, len(records))
+	idx = 0
+	for pfx, _ = range records {
+		sortedKeys[idx] = pfx
+		idx++
+	}
+	sort.SliceStable(
+		sortedKeys,
+		func(i, j int) (isBefore bool) {
+			isBefore = (netipx.ComparePrefix(sortedKeys[i], sortedKeys[j])) <= 0
+			return
+		},
+	)
+
+	fmt.Fprintf(sb, "= %s =\n", origNet.String())
+	for _, pfx = range sortedKeys {
+		rec = records[pfx]
+		fmt.Fprint(sb, sectFmts[plain][0]+"\n")
+		// Name
+		fmt.Fprintf(sb, "Reservation Name:\t%s\n", rec.Name)
+		fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Networks
+		fmt.Fprint(sb, "\tCanonical Reserved Networks:")
+		if rec.Networks != nil {
+			fmt.Fprint(sb, "\n")
+			for _, recPfx := range rec.Networks.Prefixes {
+				fmt.Fprint(sb, "\t\t"+sectFmts[plain][2]+"\n")
+				fmt.Fprintf(sb, "\t\t%s\n", recPfx.String())
+				// TODO: Print footnotes/refs!
+			}
+		} else {
+			fmt.Fprint(sb, "\t(N/A)\n")
+		}
+		fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Reference/Specification
+		fmt.Fprint(sb, "\tSpecification:")
+		if rec.Spec != nil {
+			fmt.Fprint(sb, "\n")
+			for _, line := range strings.Split(rec.Spec.Text, "\n") {
+				fmt.Fprint(sb, "\t\t"+line+"\n")
+			}
+			if rec.Spec.References != nil {
+				fmt.Fprintf(sb, "\t\t%s\n", sectFmts[plain][2])
+				for rIdx, recref := range rec.Spec.References {
+					if recref != nil {
+						fmt.Fprintf(sb, "\t\t[%d] (%s) %s\n", rIdx, recref.Type, recref.Reference)
+					}
+				}
+			}
+		} else {
+			fmt.Fprint(sb, "\t(None)\n")
+		}
+		fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Allocated (always present)
+		fmt.Fprintf(sb, "\tAllocated:\t%s\n", time.Time(rec.Allocation).String())
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Updated
+		fmt.Fprint(sb, "\tUpdated:\t")
+		if rec.Updated != nil {
+			fmt.Fprintf(sb, "%s\n", time.Time(*rec.Updated).String())
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Termination
+		fmt.Fprint(sb, "\tTerminated:\t")
+		if rec.Termination != nil {
+			fmt.Fprintf(sb, "%s\n", time.Time(*rec.Termination).String())
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Source
+		fmt.Fprint(sb, "\tValid Source:\t\t\t")
+		if rec.Source != nil {
+			if rec.Source.Applicable != nil && !bool(*rec.Source.Applicable) {
+				fmt.Fprint(sb, "(N/A)\n")
+			} else {
+				fmt.Fprintf(sb, "%v\n", bool(*rec.Source.Evaluated))
+			}
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Destination
+		fmt.Fprint(sb, "\tValid Destination:\t\t")
+		if rec.Dest != nil {
+			if rec.Dest.Applicable != nil && !bool(*rec.Dest.Applicable) {
+				fmt.Fprint(sb, "(N/A)\n")
+			} else {
+				fmt.Fprintf(sb, "%v\n", bool(*rec.Dest.Evaluated))
+			}
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Forwardable
+		fmt.Fprint(sb, "\tForwardable:\t\t\t")
+		if rec.Forwardable != nil {
+			if rec.Forwardable.Applicable != nil && !bool(*rec.Forwardable.Applicable) {
+				fmt.Fprint(sb, "(N/A)\n")
+			} else {
+				fmt.Fprintf(sb, "%v\n", bool(*rec.Forwardable.Evaluated))
+			}
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Globally reachable
+		fmt.Fprint(sb, "\tGlobally Routable/Reachable:\t")
+		if rec.GlobalReach != nil {
+			if rec.GlobalReach.Applicable != nil && !bool(*rec.GlobalReach.Applicable) {
+				fmt.Fprint(sb, "(N/A)\n")
+			} else {
+				fmt.Fprintf(sb, "%v\n", bool(*rec.GlobalReach.Evaluated))
+			}
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+		// fmt.Fprint(sb, "\t"+sectFmts[plain][1]+"\n")
+		// Reserved by Protocol
+		fmt.Fprint(sb, "\tReserved by Protocol:\t\t")
+		if rec.ProtoReserved != nil {
+			if rec.ProtoReserved.Applicable != nil && !bool(*rec.ProtoReserved.Applicable) {
+				fmt.Fprint(sb, "(N/A)\n")
+			} else {
+				fmt.Fprintf(sb, "%v\n", bool(*rec.ProtoReserved.Evaluated))
+			}
+		} else {
+			fmt.Fprint(sb, "(N/A)\n")
+		}
+	}
+
+	fmt.Print(sb.String())

 	return
 }
--- a/cmd/subnetter/funcs_tpl.go
+++ b/cmd/subnetter/funcs_tpl.go
@@ -12,7 +12,7 @@ import (
 	`github.com/TwiN/go-color`
 	`github.com/projectdiscovery/mapcidr`
 	`go4.org/netipx`
-	`subnetter/netsplit`
+	`r00t2.io/subnetter/netsplit`
 )

 // renderHdr renders a header. Note that the first line does *not* include the indent, but subsequent ones do.
--- a/cmd/subnetter/funcs_vlsmargs.go
+++ b/cmd/subnetter/funcs_vlsmargs.go
@@ -0,0 +1,26 @@
+package main
+
+/*
+	AllSizes returns a properly parsed and consolidated slice
+	of all specified sizes, as it takes two valid syntaxes (`-s 32 -s 32`, `-s 32,32`)
+	that can be mixed together.
+*/
+func (v *VLSMArgs) AllSizes() (sizes []uint8, err error) {
+
+	var sizeSlice []uint8
+
+	if v == nil {
+		return
+	}
+	if v.Sizes == nil || len(v.Sizes) == 0 {
+		return
+	}
+	for _, s := range v.Sizes {
+		if sizeSlice, err = s.Sizes(); err != nil {
+			return
+		}
+		sizes = append(sizes, sizeSlice...)
+	}
+
+	return
+}
--- a/cmd/subnetter/funcs_vlsmsize.go
+++ b/cmd/subnetter/funcs_vlsmsize.go
@@ -0,0 +1,33 @@
+package main
+
+import (
+	`strconv`
+	`strings`
+)
+
+// Sizes returns a parsed/split slice of uint8s from a vlsmSize.
+func (v *vlsmSize) Sizes() (sizes []uint8, err error) {
+
+	var s []string
+	var u uint64
+
+	if v == nil {
+		return
+	}
+	s = strings.Split(string(*v), ",")
+	for idx, i := range s {
+		s[idx] = strings.TrimSpace(i)
+	}
+
+	sizes = make([]uint8, len(s))
+
+	// No validation is performed since we don't have access to the addr inet family; that's up to the parsers.
+	for idx, i := range s {
+		if u, err = strconv.ParseUint(i, 10, 8); err != nil {
+			return
+		}
+		sizes[idx] = uint8(u)
+	}
+
+	return
+}
--- a/cmd/subnetter/main.go
+++ b/cmd/subnetter/main.go
@@ -3,7 +3,7 @@ package main
 import (
 	"bytes"
 	"errors"
-	`fmt`
+	"fmt"
 	"io"
 	"log"
 	"net"
@@ -12,8 +12,8 @@ import (
 	"strings"

 	"go4.org/netipx"
-	"subnetter/netsplit"
-	`subnetter/version`
+	"r00t2.io/subnetter/netsplit"
+	"r00t2.io/subnetter/version"

 	"github.com/jessevdk/go-flags"
 	"r00t2.io/sysutils/paths"
@@ -26,14 +26,18 @@ func main() {
 	var pfx *net.IPNet
 	var resPfx *netip.Prefix
 	var origPfx netip.Prefix
+	var vlsmSizes []uint8
 	var splitter netsplit.NetSplitter
 	var cmnArgs common
 	var nets []*netip.Prefix
 	var remaining *netipx.IPSet
 	var buf *bytes.Buffer
 	var res *netsplit.StructuredResults
+	var numNets uint
+	var v6Only bool
 	var noStrict bool
 	var strictErr error
+	var reservations map[netip.Prefix]*netsplit.IANAAddrNetResRecord
 	var splitErr *netsplit.SplitErr = new(netsplit.SplitErr)
 	var parser *flags.Parser = flags.NewParser(args, flags.Default)

@@ -77,8 +81,47 @@ func main() {
 			log.Panicln(err)
 		}
 		return
+	case "num-nets":
+		if numNets, v6Only, err = netsplit.NumNets(
+			args.NumNets.Sizes.SubnetSize,
+			args.NumNets.Sizes.NetworkSize,
+		); err != nil {
+			log.Panicln(err)
+		}
+		if !args.NumNets.Verbose {
+			fmt.Printf("%d\n", numNets)
+			if !args.NumNets.NoV6Check {
+				fmt.Println(v6Only)
+			}
+		} else {
+			fmt.Printf("Network Size:\t\t\t%d\n", args.NumNets.Sizes.NetworkSize)
+			fmt.Printf("Subnet Size:\t\t\t%d\n", args.NumNets.Sizes.SubnetSize)
+			fmt.Printf("Number of Subnets:\t\t%d\n", numNets)
+			if !args.NumNets.NoV6Check {
+				fmt.Printf("Subnetting is IPv6-Only:\t%v\n", v6Only)
+			}
+		}
+		return
 	case "reserved":
-		// TODO
+		if origPfx, err = netip.ParsePrefix(args.Check.Network.Network); err != nil {
+			log.Panicln(err)
+		}
+		nets = make([]*netip.Prefix, 1)
+		nets[0] = new(netip.Prefix)
+		*nets[0] = origPfx
+		if err = netsplit.SetCachePath(args.Check.CacheDir); err != nil {
+			log.Panicln(err)
+		}
+		if err = netsplit.EnableCache(args.Check.DoResCache); err != nil {
+			log.Panicln(err)
+		}
+		if reservations, err = netsplit.CheckReserved(nets, !args.Check.NoRevRecursive, !args.Check.NoRecursive, !args.Check.NoPrivate); err != nil {
+			log.Panicln(err)
+		}
+		if err = printReserved(reservations, origPfx, args.Check.Plain, args.Check.Fmt); err != nil {
+			log.Panicln(err)
+		}
+		return
 	case "table":
 		// Account for a weird redundant CLI condition.
 		if args.Table.NoIpv4 && args.Table.NoIpv6 {
@@ -116,7 +159,12 @@ func main() {
 			origPfx = *resPfx
 		}
 		pfx = netipx.PrefixIPNet(origPfx.Masked())
-		cmnArgs = args.Parse.common
+		cmnArgs = common{
+			commonBase: args.Parse.commonBase,
+			Network: Net{
+				Network: res.Original.String(),
+			},
+		}
 		if err = printNets(&origPfx, pfx, nets, remaining, &cmnArgs, res.GetSplitter()); err != nil {
 			log.Panicln(err)
 		}
@@ -165,14 +213,18 @@ func main() {
 				PrefixLength: args.SplitCIDR.Prefix,
 				BaseSplitter: new(netsplit.BaseSplitter),
 			}
-		case "vlsm":
+		case "split-vlsm":
 			if err = validate.Struct(args.VLSM); err != nil {
 				log.Panicln(err)
 			}
 			cmnArgs = args.VLSM.common
+			if vlsmSizes, err = args.VLSM.AllSizes(); err != nil {
+				log.Panicln(err)
+			}
 			splitter = &netsplit.VLSMSplitter{
 				Ascending:     args.VLSM.Asc,
-				PrefixLengths: args.VLSM.Sizes,
+				Explicit:      args.VLSM.Explicit,
+				PrefixLengths: vlsmSizes,
 				BaseSplitter:  new(netsplit.BaseSplitter),
 			}
 		default:
--- a/cmd/subnetter/types.go
+++ b/cmd/subnetter/types.go
@@ -1,11 +1,11 @@
 package main

 import (
-	`math/big`
-	`net`
+	"math/big"
+	"net"
 	"net/netip"

-	`subnetter/netsplit`
+	"r00t2.io/subnetter/netsplit"
 )

 // subnetResult is only used for human/"pretty" printing.
@@ -96,6 +96,9 @@ type tableFormatter struct {
 	NoBoldTitle     bool
 }

+// vlsmSize is a custom type to let us specify multiple sizes as a repeated or consolidated argument.
+type vlsmSize string
+
 type ReservedResults struct {
 	Opts     CheckArgs
 	Reserved map[netip.Prefix]*netsplit.IANAAddrNetResRecord
--- a/go.mod
+++ b/go.mod
@@ -1,19 +1,17 @@
-module subnetter
+module r00t2.io/subnetter

-go 1.23.2
-
-toolchain go1.23.5
+go 1.24.0

 require (
 	github.com/TwiN/go-color v1.4.1
-	github.com/davecgh/go-spew v1.1.1
-	github.com/go-playground/validator/v10 v10.24.0
+	github.com/go-playground/validator/v10 v10.25.0
 	github.com/go-resty/resty/v2 v2.16.5
-	github.com/goccy/go-yaml v1.15.16
+	github.com/goccy/go-yaml v1.15.23
 	github.com/jessevdk/go-flags v1.6.1
 	github.com/projectdiscovery/mapcidr v1.1.34
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba
-	golang.org/x/mod v0.22.0
+	golang.org/x/mod v0.24.0
+	r00t2.io/goutils v1.8.1
 	r00t2.io/sysutils v1.12.0
 )

@@ -28,12 +26,11 @@ require (
 	github.com/microcosm-cc/bluemonday v1.0.27 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/projectdiscovery/blackrock v0.0.1 // indirect
-	github.com/projectdiscovery/utils v0.4.9 // indirect
+	github.com/projectdiscovery/utils v0.4.14 // indirect
 	github.com/saintfish/chardet v0.0.0-20230101081208-5e3ef4b5456d // indirect
-	golang.org/x/crypto v0.32.0 // indirect
-	golang.org/x/net v0.34.0 // indirect
-	golang.org/x/sync v0.10.0 // indirect
-	golang.org/x/sys v0.29.0 // indirect
-	golang.org/x/text v0.21.0 // indirect
-	r00t2.io/goutils v1.7.2 // indirect
+	golang.org/x/crypto v0.36.0 // indirect
+	golang.org/x/net v0.37.0 // indirect
+	golang.org/x/sync v0.12.0 // indirect
+	golang.org/x/sys v0.31.0 // indirect
+	golang.org/x/text v0.23.0 // indirect
 )
--- a/go.sum
+++ b/go.sum
@@ -15,19 +15,23 @@ github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/o
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
 github.com/go-playground/universal-translator v0.18.1/go.mod h1:xekY+UJKNuX9WP91TpwSH2VMlDf28Uj24BCp08ZFTUY=
-github.com/go-playground/validator/v10 v10.24.0 h1:KHQckvo8G6hlWnrPX4NJJ+aBfWNAE/HH+qdL2cBpCmg=
-github.com/go-playground/validator/v10 v10.24.0/go.mod h1:GGzBIJMuE98Ic/kJsBXbz1x/7cByt++cQ+YOuDM5wus=
+github.com/go-playground/validator/v10 v10.25.0 h1:5Dh7cjvzR7BRZadnsVOzPhWsrwUr0nmsZJxEAnFLNO8=
+github.com/go-playground/validator/v10 v10.25.0/go.mod h1:GGzBIJMuE98Ic/kJsBXbz1x/7cByt++cQ+YOuDM5wus=
 github.com/go-resty/resty/v2 v2.16.5 h1:hBKqmWrr7uRc3euHVqmh1HTHcKn99Smr7o5spptdhTM=
 github.com/go-resty/resty/v2 v2.16.5/go.mod h1:hkJtXbA2iKHzJheXYvQ8snQES5ZLGKMwQ07xAwp/fiA=
-github.com/goccy/go-yaml v1.15.16 h1:PMTVcGI9uNPIn7KLs0H7KC1rE+51yPl5YNh4i8rGuRA=
-github.com/goccy/go-yaml v1.15.16/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
+github.com/goccy/go-yaml v1.15.23 h1:WS0GAX1uNPDLUvLkNU2vXq6oTnsmfVFocjQ/4qA48qo=
+github.com/goccy/go-yaml v1.15.23/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
+github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
 github.com/gorilla/css v1.0.1 h1:ntNaBIghp6JmvWnxbZKANoLyuXTPZ4cAMlo6RyhlbO8=
 github.com/gorilla/css v1.0.1/go.mod h1:BvnYkspnSzMmwRK+b8/xgNPLiIuNZr6vbZBTPQ2A3b0=
 github.com/jessevdk/go-flags v1.6.1 h1:Cvu5U8UGrLay1rZfv/zP7iLpSHGUZ/Ou68T0iX1bBK4=
 github.com/jessevdk/go-flags v1.6.1/go.mod h1:Mk8T1hIAWpOiJiHa9rJASDK2UGWji0EuPGBnNLMooyc=
 github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
+github.com/microcosm-cc/bluemonday v1.0.25 h1:4NEwSfiJ+Wva0VxN5B8OwMicaJvD8r9tlJWm9rtloEg=
+github.com/microcosm-cc/bluemonday v1.0.25/go.mod h1:ZIOjCQp1OrzBBPIJmfX4qDYFuhU02nx4bn030ixfHLE=
 github.com/microcosm-cc/bluemonday v1.0.27 h1:MpEUotklkwCSLeH+Qdx1VJgNqLlpY2KXwXFM08ygZfk=
 github.com/microcosm-cc/bluemonday v1.0.27/go.mod h1:jFi9vgW+H7c3V0lb6nR74Ib/DIB5OBs92Dimizgw2cA=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -38,8 +42,10 @@ github.com/projectdiscovery/blackrock v0.0.1 h1:lHQqhaaEFjgf5WkuItbpeCZv2DUIE45k
 github.com/projectdiscovery/blackrock v0.0.1/go.mod h1:ANUtjDfaVrqB453bzToU+YB4cUbvBRpLvEwoWIwlTss=
 github.com/projectdiscovery/mapcidr v1.1.34 h1:udr83vQ7oz3kEOwlsU6NC6o08leJzSDQtls1wmXN/kM=
 github.com/projectdiscovery/mapcidr v1.1.34/go.mod h1:1+1R6OkKSAKtWDXE9RvxXtXPoajXTYX0eiEdkqlhQqQ=
-github.com/projectdiscovery/utils v0.4.9 h1:GzYKy5iiCWEZZPGxrtgTOnRTZYiIAiCditGufp0nhGU=
-github.com/projectdiscovery/utils v0.4.9/go.mod h1:/68d0OHGgYF4aW4X7kS1qlFlYOnZxgtFDN85iH732JI=
+github.com/projectdiscovery/utils v0.0.85 h1:JpCVc9GJwJLNHy1MBPmAHJcE6rs7bRv72Trb3u84OHE=
+github.com/projectdiscovery/utils v0.0.85/go.mod h1:ttiPgS2LmLFd+VRBUdgfLKMMdrF98zX7z5W+K71MX40=
+github.com/projectdiscovery/utils v0.4.14 h1:BrEfO4f4P+Hu58jNfjho2aRt/Y4jxKhTVQqs2Ei4670=
+github.com/projectdiscovery/utils v0.4.14/go.mod h1:y5gnpQn802iEWqf0djTRNskJlS62P5eqe1VS1+ah0tk=
 github.com/saintfish/chardet v0.0.0-20230101081208-5e3ef4b5456d h1:hrujxIzL1woJ7AwssoOcM/tq5JjjG2yYOc8odClEiXA=
 github.com/saintfish/chardet v0.0.0-20230101081208-5e3ef4b5456d/go.mod h1:uugorj2VCxiV1x+LzaIdVa9b4S4qGAcH6cbhh4qVxOU=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
@@ -48,24 +54,34 @@ go4.org/netipx v0.0.0-20231129151722-fdeea329fbba h1:0b9z3AuHCjxk0x/opv64kcgZLBs
 go4.org/netipx v0.0.0-20231129151722-fdeea329fbba/go.mod h1:PLyyIXexvUFg3Owu6p/WfdlivPbZJsZdgWZlrGope/Y=
 golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
 golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
-golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=
-golang.org/x/mod v0.22.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
+golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
+golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
+golang.org/x/mod v0.24.0 h1:ZfthKaKaT4NrhGVZHO1/WDTwGES4De8KtWO0SIbNJMU=
+golang.org/x/mod v0.24.0/go.mod h1:IXM97Txy2VM4PJ3gI61r1YEk/gAj6zAHN3AdZt6S9Ww=
 golang.org/x/net v0.34.0 h1:Mb7Mrk043xzHgnRM88suvJFwzVrRfHEHJEl5/71CKw0=
 golang.org/x/net v0.34.0/go.mod h1:di0qlW3YNM5oh6GqDGQr92MyTozJPmybPK4Ev/Gm31k=
+golang.org/x/net v0.37.0 h1:1zLorHbz+LYj7MQlSf1+2tPIIgibq2eL5xkrGk6f+2c=
+golang.org/x/net v0.37.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
 golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
 golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.12.0 h1:MHc5BpPuC30uJk597Ri8TV3CNZcTLu6B6z4lJy+g6Jw=
+golang.org/x/sync v0.12.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
 golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
+golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
+golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
+golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
 golang.org/x/time v0.6.0 h1:eTDhh4ZXt5Qf0augr54TN6suAUudPcawVZeIAPU7D4U=
 golang.org/x/time v0.6.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-r00t2.io/goutils v1.7.2 h1:dJ+pzY/U1yVi2V6eKoxe/4roM+Tb3d0umMEL9Dx4+Lw=
-r00t2.io/goutils v1.7.2/go.mod h1:9ObJI9S71wDLTOahwoOPs19DhZVYrOh4LEHmQ8SW4Lk=
+r00t2.io/goutils v1.8.1 h1:TQcUycPKsYn0QI4uCqb56utmvu/vVSxlblBg98iXStg=
+r00t2.io/goutils v1.8.1/go.mod h1:9ObJI9S71wDLTOahwoOPs19DhZVYrOh4LEHmQ8SW4Lk=
 r00t2.io/sysutils v1.1.1/go.mod h1:Wlfi1rrJpoKBOjWiYM9rw2FaiZqraD6VpXyiHgoDo/o=
 r00t2.io/sysutils v1.12.0 h1:Ce3qUOyLixE1ZtFT/+SVwOT5kSkzg5+l1VloGeGugrU=
 r00t2.io/sysutils v1.12.0/go.mod h1:bNTKNBk9MnUhj9coG9JBNicSi5FrtJHEM645um85pyw=
--- a/netsplit/conts.go
+++ b/netsplit/conts.go
@@ -8,6 +8,12 @@ import (
 	`github.com/go-resty/resty/v2`
 )

+const (
+	maxBitsv4 uint8 = 32
+	maxBitsv6 uint8 = 128
+	maxBits   uint8 = maxBitsv6
+)
+
 const (
 	cachedirEnvName string = "SBNTR_RSVCACHE_DIR"
 	// https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
--- a/netsplit/funcs.go
+++ b/netsplit/funcs.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"encoding/xml"
 	"fmt"
+	`math`
 	"net"
 	"net/netip"
 	"strings"
@@ -375,6 +376,38 @@ func MaskInvert(mask net.IPMask) (inverted net.IPMask) {
 	return
 }

+/*
+	NumNets returns the number of times prefix size subnet fits into prefix size network.
+
+	It will error if network is larger than 128 or if subnet is smaller than network.
+
+	This is MUCH more performant than splitting out an actual network into explicit subnets,
+	and does not require an actual network.
+*/
+func NumNets(subnet, network uint8) (numNets uint, ipv6Only bool, err error) {
+
+	var x float64
+
+	// network cannot be higher than 128, as that's the maximum for IPv6.
+	if network > maxBits {
+		err = ErrBadPrefixLen
+		return
+	}
+	if subnet < network {
+		err = ErrBigPrefix
+		return
+	}
+	if network > maxBitsv4 {
+		ipv6Only = true
+	}
+
+	x = float64(subnet - network)
+
+	numNets = uint(math.Pow(2, x))
+
+	return
+}
+
 // Parse parses b for JSON/XML/YAML and tries to return a StructuredResults from it.
 func Parse(b []byte) (s *StructuredResults, err error) {

--- a/netsplit/funcs_cache.go
+++ b/netsplit/funcs_cache.go
@@ -195,6 +195,7 @@ func SetCachePath(cacheDirPath string) (err error) {
 	}

 	if cacheDirPath != oldPath {
+		cacheDir = cacheDirPath
 		if err = os.MkdirAll(cacheDir, cacheDirPerms); err != nil {
 			return
 		}
--- a/netsplit/funcs_cidrsplitter.go
+++ b/netsplit/funcs_cidrsplitter.go
@@ -31,7 +31,7 @@ func (c *CIDRSplitter) Split() (nets []*netip.Prefix, remaining *netipx.IPSet, e
 		return
 	}

-	if c.PrefixLength > uint8(base.Bits()) {
+	if c.PrefixLength < uint8(base.Bits()) {
 		err = ErrBigPrefix
 		return
 	}
@@ -48,11 +48,11 @@ func (c *CIDRSplitter) Split() (nets []*netip.Prefix, remaining *netipx.IPSet, e
 				// We just hit the end of the prefix.
 				break
 			}
+		}
 		subPtr = new(netip.Prefix)
 		*subPtr = sub
 		nets = append(nets, subPtr)
 	}
-	}

 	return
 }
--- a/netsplit/funcs_vlsmsplitter.go
+++ b/netsplit/funcs_vlsmsplitter.go
@@ -2,7 +2,7 @@ package netsplit

 import (
 	"net/netip"
-	"sort"
+	`sort`

 	"go4.org/netipx"
 )
@@ -42,6 +42,7 @@ func (v *VLSMSplitter) Split() (nets []*netip.Prefix, remaining *netipx.IPSet, e
 		return
 	}

+	if !v.Explicit {
 		sort.SliceStable(
 			v.PrefixLengths,
 			func(i, j int) (isBefore bool) { // We use a reverse sorting by default so we get larger prefixes at the beginning.
@@ -53,6 +54,7 @@ func (v *VLSMSplitter) Split() (nets []*netip.Prefix, remaining *netipx.IPSet, e
 				return
 			},
 		)
+	}

 	pfxLen, _ = v.network.Mask.Size()
 	pfxLen8 = uint8(pfxLen)
--- a/netsplit/types.go
+++ b/netsplit/types.go
@@ -79,6 +79,13 @@ type VLSMSplitter struct {
 		You almost assuredly do not want to do this.
 	*/
 	Ascending bool
+	/*
+		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
 	// 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"`
Author	SHA1	Message	Date
brent saner	3c239a4d09	v0.2.0 ADDED: * num-nets subcommand' this is MUCH much faster than actually splitting if you're trying to figure out how many times a given subnet fits into a network.	2025-04-06 01:31:51 -04:00
brent saner	701b598b1c	update TODO with bug to look into	2025-04-04 14:33:39 -04:00
brent saner	32297d1bba	v0.1.2 FIXED: * Missing reservation checker	2025-04-04 14:29:07 -04:00
brent saner	d37aa3eb6b	v0.1.1 ADDED: * The -s/--size argument to the VLSM splitter may now be a comma-delimited list of sizes instead of needing to specify -s/--size for each size. This change is backwards-compatible.	2025-04-04 11:53:55 -04:00
brent saner	0c8577f149	v0.1.0 ADDED: * Explicit subnet ordering option for VLSM	2025-04-03 18:35:35 -04:00
brent saner	166fb3be23	v0.0.2 FIXED: * Ooops, fix go mod	2025-03-10 10:07:51 -04:00