Hi, Tom & Paul:
1) " ... hand waved ... ": Through my line of work, I was trained
to behave exactly the opposite. I am surprised at you jumping to the
conclusion, even before challenging me about where did I get my
viewpoint from. The fact is, it has been clearly documented in our IETF
draft for the last couple years (since Rev-06 on 2019 Dec. 1)! For your
convenience, please see below a copy of the potential target code
fragment and critique. It appears to me that our software member
suggested to comment out only one line (1047).
Regards,
Abe (2022-03-26 18:16)
****************
D.1
<https://datatracker.ietf.org/doc/html/draft-chen-ati-adaptive-ipv4-address-space#appendix-D.1>.
Candidate Code for Modification
The following short JavaScript function named "ifip" in the TP-Link
Archer C20 V4 source code has been shown to selectively reject
specific ranges of IP addresses. In particular, Line 1047 uses a "2's
Complement" technique to identify the 240/4 netblock as "PRESERVED",
thus rejecting it. A quick scan of the firmware code in the router
indicates that this function is a popular utility because there are
numerous processes calling for it. So, this should be the best
candidate to start testing our concept.
lib.js:1040:ifip: function(ip, unalert) {
lib.js-1041-if ((ip = $.ip2num(ip)) === false) return $.alert(ERR_IP_FORMAT,
unalert);
lib.js-1042-if (ip == -1) return $.alert(ERR_IP_BROADCAST, unalert);
lib.js-1043-var net = ip >> 24;
lib.js-1044-if (net == 0) return $.alert(ERR_IP_SUBNETA_NET_0, unalert);
lib.js-1045-if (net == 127) return $.alert(ERR_IP_LOOPBACK, unalert);
lib.js-1046-if (net >= -32 && net < -16) return $.alert(ERR_IP_MULTICAST,
unalert);
lib.js-1047-if (net >= -16 && net < 0) return $.alert(ERR_IP_PRESERVED,
unalert);
lib.js-1048-return 0;
lib.js-1049-},
D.2
<https://datatracker.ietf.org/doc/html/draft-chen-ati-adaptive-ipv4-address-space-10#appendix-D.2>.
Proposed Modification
To stop rejecting the 240/4 netblock addressed packets, below is a
modification that comments out Line 1047, a modification that has
been shown to eliminate javascript pre-validation of 240/4 IP
addresses, allowing them to be sent within the router, where a second
layer of validation rejects them in a different way.
lib.js:1040: ifip: function(ip, unalert) {
lib.js-1041- if ((ip = $.ip2num(ip)) === false) return
$.alert(ERR_IP_FORMAT, unalert);
lib.js-1042- if (ip == -1) return $.alert(ERR_IP_BROADCAST, unalert);
lib.js-1043- var net = ip >> 24;
lib.js-1044- if (net == 0) return $.alert(ERR_IP_SUBNETA_NET_0, unalert);
lib.js-1045- if (net == 127) return $.alert(ERR_IP_LOOPBACK, unalert);
lib.js-1046- if (net >= -32 && net < -16) return $.alert(ERR_IP_MULTICAST,
unalert);
lib.js-1047- //if (net >= -16 && net < 0) return $.alert(ERR_IP_PRESERVED,
unalert);
lib.js-1048- return 0;
lib.js-1049-},
****************
On 2022-03-26 12:37, Tom Beecher wrote:
Have you ever considered that this may be in fact:
*/writing/* and */deploying/* the code that will allow the use of
240/4 the
way you expect
While Mr. Chen may have considered that, he has repeatedly hand waved
that it's 'not that big a deal.', so I don't think he
adequately grasps the scale of that challenge.
On Sat, Mar 26, 2022 at 9:53 AM Paul Rolland <r...@witbe.net> wrote:
Hello,
On Sat, 26 Mar 2022 09:35:30 -0400
"Abraham Y. Chen" <ayc...@avinta.com> wrote:
> touching the hardware, by implementing the EzIP technique
(*/disabling/*
> the program code that has been */disabling/* the use of the 240/4
> netblock), an existing CG-NAT module becomes a RAN! As to universal
Have you ever considered that this may be in fact:
*/writing/* and */deploying/* the code that will allow the use of
240/4 the
way you expect
Paul
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