mikioh / ipaddr Goto Github PK

If you call ipaddr.Parse with input that is only a single IP (127.0.0.1, 127.0.0.1/32) the supplied cursor will not return any entries via Next(). Getting the value via First() works fine.

I believe Next() should return the first, and only entry, and then return nil.

I am parsing a mix of single hosts and networks both in CIDR notation and noticed that anything with a /32 prefix was being dropped because of Next() returning nil immediately.

Here is an example program to show the issue.

https://play.golang.org/p/xZEOyiLCXYN

`package main

import (
"fmt"
"github.com/mikioh/ipaddr"
)

func printIPs(ip string) {
cursor, err := ipaddr.Parse(ip)
if err != nil {
fmt.Println(err)
} else {
fmt.Println(cursor.Pos(), cursor.First(), cursor.Last(), cursor.List())
fmt.Println("First is: ", cursor.First().IP.String())
fmt.Println("All Members:")
for pos := cursor.Next(); pos != nil; pos = cursor.Next() {
fmt.Println(pos.IP.String())
}
}
}

func main() {
printIPs("192.168.168.77/32")
printIPs("127.0.0.1/32")
printIPs("127.0.0.0/29")
}
`

There is an issue when aggregating a large volume of subnets which causes a null pointer panic

This though does not occur when using Python's standard library to collapse addresses.

Example output:

Converting subnets to Prefixes
Aggregating subnets
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x10b2f1a]

goroutine 1 [running]:
github.com/mikioh/ipaddr.aggregateByBF(0xc000694000, 0x19233, 0x19233, 0x1283ef8, 0x1283f08, 0x4, 0x19233, 0x19233)
        /Users/kkirsche/git/go/pkg/mod/github.com/mikioh/[email protected]/prefix.go:329 +0x69a
github.com/mikioh/ipaddr.Aggregate(0xc000694000, 0x19233, 0x19233, 0x1, 0x1, 0x14)
        /Users/kkirsche/git/go/pkg/mod/github.com/mikioh/[email protected]/prefix.go:302 +0x103
main.main()
        /Users/kkirsche/git/go/src/github.com/kkirsche/ipaddr-aggregation-error/main.go:27 +0x18a
exit status 2

I've created a repository with a python and a go version showing that one works and one does not.

https://github.com/kkirsche/ipaddr-aggregation-error

Aggregation incorrect with different seq of prefix

results of {"8.8.8.0/25","8.8.8.128/25", "9.9.9.0/25"} is [8.8.8.0/24 9.9.9.0/25], which is correct
but if you change the seq of your input to {"8.8.8.0/25", "9.9.9.0/25","8.8.8.128/25"}, and result is [8.0.0.0/7] , which is wrong

Given the input:

127.156.0.0/15
127.159.0.0/16

Aggregate produces:

127.156.0.0/14

But that includes the range 127.158.0.0/16 which is not in the input.

I also think there is an infinite loop somewhere with some inputs but I haven't managed to narrow down a test case yet.

It seems like on some sets of prefixes (128.0.0.0/1 and 0.0.0.0/1 in my case), it causes infinity loop:

func branchingFactorIPv4(ps []Prefix) (int, bool) {
	var lastBF, lastN int
	base := ipToIPv4Int(ps[0].IP.Mask(ps[0].Mask))
	mask := ipMaskToIPv4Int(ps[0].Mask)
	l := ps[0].Len()
	for bf := 1; bf < IPv4PrefixLen; bf++ {
		n, nfull := 0, 1<<uint(bf)
		max := ipv4Int(1 << uint(bf))
		aggrMask := mask << uint(bf)
		for pat := ipv4Int(0); pat < max; pat++ {
			aggr := base&aggrMask | pat<<uint(IPv4PrefixLen-l)
			for _, p := range ps {
				i := ipToIPv4Int(p.IP)
				if aggr == i&mask {
					n++
				}
			}
		}
		if n < nfull {
			break
		}
		lastBF = bf
		lastN = n
	}
	n := 1 << uint(lastBF)
	return n, lastN >= n
}

After some calculation it causes panic:

runtime error: slice bounds out of range [:2147483648] with capacity 24

Aggregate function with specific prefix list cause the error. Interesting thing is that commenting any of subnets makes program work correct.

https://go.dev/play/p/a83OovyO0mV

package main

import (
	"net"

	"github.com/mikioh/ipaddr"
)

func main() {
	subnets := []string{
		"109.233.200.0/22",
		"109.233.204.0/22",
		"109.233.208.0/21",
		"109.233.224.0/21",
		"109.234.36.0/22",
		"109.234.128.0/21",
		"109.234.152.0/21",
		"109.235.24.0/21",
		"109.235.88.0/21",
		"109.235.160.0/21",
		"109.235.184.0/21",
		"146.185.208.0/22",
		"178.213.75.0/24",
	}

	var prefixes []ipaddr.Prefix

	for _, v := range subnets {
		_, cidr, _ := net.ParseCIDR(v)
		p := ipaddr.NewPrefix(cidr)
		prefixes = append(prefixes, *p)
	}
	ipaddr.Aggregate(prefixes)
}