Hello,
It seems that never versions of iproute (tested with iproute2-2.6.26) no

longer allow 0/0:
# ip route add 0/0 via 192.168.0.1

Error: an inet prefix is expected rather than "0/0".
Is it intentional? It breaks startup scripts.
Best regards,
 			Krzysztof Ol

OK, never mind - found it:
http://git.kernel.org/?p=linux/kernel/git/shemminger/iproute2.git;a=comm...
;)
Best regards,
 				Krzysztof Ol

Hmm, this breaks several scripts of mine that use 10/8.  Couldn't

we just fall back to the old loop when inet_aton fails?
Thanks,

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On Tue, 14 Oct 2008 22:01:27 +0800
There is no easy solution, I'll will have to go back rewrite this

code, and will document the result. I expect the result will displease

someone, but given the original code that is just going to happen.
Busted cases:

                           correct           incorrect

Original code: 127.2   =>  127.0.0.2         127.2.0.0

inet_pton:     10.0    =>  10.0.0.0          fails invalid

inet_aton:     10      =>  10.0.0.0          0.0.0.10
The problem was Alexey (or Jamal) invented their own abbreviation format

and did not follow unix standard conventions.

--

How about just keeping Alexey's code? POSIX doesn't restrict

the IP address format command utilities should accept.  So to

me 127.2.0.0 is a perfectly acceptable interpretation of the

partial address 127.2.
This also has the benefit of not breaking any existing scripts

that already work.  The scripts which are broken will remain

broken which doesn't surprise anyone.
Cheers,

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Then it would be better to disallow such things. The normal meaning

for "127.2" was always 127.0.0.2, and it was widely documented and

used (though perhaps in RFCs, not in POSIX). Some people use "10.1"
Any script which uses 127.2 to mean 127.2.0.0 is IMHO broken, though

I have never seen anything like that.
Rules always have been simple:

10	- 10.0.0.0

10.1	- 10.0.0.1

10.1.2	- 10.0.1.2
If it can't stay this way, lets remove this shortened notation

completely.

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Krzysztof Halasa

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It's a Berkeley extension which spread via BSD and its inet_aton()
No, a single number is treated by inet_aton() as a 32-bit address, so 10
Ben.
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Ben Hutchings, Senior Software Engineer, Solarflare Communications

Not speaking for my employer; that's the marketing department's job.

They asked us to note that Solarflare product names are trademarked.
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You may be right, I won't start searching now :-)

Anyway it was like that for years and I guess we shouldn't change it
Hmm, I remember some routes being used without a dot, as a single

number, but OTOH you're right, it was also possible to ping

12345678. Perhaps 10 -> 10.0 was specific to something rather than

used generally, I don't know.

--

Krzysztof Halasa

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On Wed, 15 Oct 2008 20:52:47 +0200
I ended up putting in a version similar to the original code but with

more error checking so it would not accept 259.1 etc.

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Thanks Stephen!

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We fixed the same problem in iptables a few years ago, maybe you could

reuse some of that code. Some quick testing shows that it parses all

addresses according to your table:
# iptables -I OUTPUT -d 127.2

# iptables -I OUTPUT -d 10.0

# iptables -I OUTPUT -d 10

# iptables -vxnL OUTPUT

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)

     pkts      bytes target     prot opt in     out     source

      destination

        0        0            all  --  *      *       0.0.0.0/0

    10.0.0.0

        0        0            all  --  *      *       0.0.0.0/0

    10.0.0.0

        0        0            all  --  *      *       0.0.0.0/0

    127.2.0.0
You can find the code in "xtables.c", function numeric_to_ipaddr().

--

OK, the last one is wrong. I thought we fixed that :)

--

It seems that the original code followed the unix standard:
# telnet 127.2

Trying 127.0.0.2...

telnet: connect to address 127.0.0.2: Connection refused
Best regards,
 				Krzysztof Ol

On Tue, 14 Oct 2008 21:15:18 +0200 (CEST)
The incorrect column lists the actual result for each of the routines.

Original code converted 127.2 to 127.2.0.0

--

[...]
If only the one-component case needs to be treated specially then you

should be able to use something like:
	/* For backward compatibility, if name is all digits we treat it as

	 * the top 8 bits of an IPv4 address. */

	if (strspn(name, "0123456789") == strlen(name))

		addr->data[0] = atoi(name);

	else if (inet_aton(name, addr->data) > 0)

		;

	else

 		return -1;
But if people also rely on e.g. 192.168/16 working then it gets

trickier.
Ben.
--

Ben Hutchings, Senior Software Engineer, Solarflare Communications

Not speaking for my employer; that's the marketing department's job.

They asked us to note that Solarflare product names are trademarked.
--