MySQL Bugs: #120874: MySQL's INET6_NTOA function is not RFC 5952 complaint

Bug #120874	MySQL's INET6_NTOA function is not RFC 5952 complaint
Submitted:	6 Jul 13:30	Modified:	7 Jul 6:36
Reporter:	Aaditya Dubey	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:	8.4.x, 9.7.x	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Section 4.2.2 of RFC5952 says "::" should not be used to shorten one 16-bit 0 field. But the current INET6_NTOA function in MySQL seems to shorten it.

Reference: https://www.rfc-editor.org/info/rfc5952/#section-4.2.2

Code Reference: https://github.com/mysql/mysql-server/blob/845d525d49c8027a4d0cdcc43372c96ba295c857/sql/it...

How to repeat:
Sample current output:

mysql> SELECT INET6_NTOA(UNHEX('00010002000300040005000600070000'));
+-------------------------------------------------------+
| INET6_NTOA(UNHEX('00010002000300040005000600070000')) |
+-------------------------------------------------------+
| 1:2:3:4:5:6:7::                                       |
+-------------------------------------------------------+
1 row in set (0.001 sec)

The last field is a one 16bit 0 field. This has be shortened to "::". Ideally this should be the output:

mysql> SELECT INET6_NTOA(UNHEX('00010002000300040005000600070000'));
+-------------------------------------------------------+
| INET6_NTOA(UNHEX('00010002000300040005000600070000')) |
+-------------------------------------------------------+
| 1:2:3:4:5:6:7:0                                       |
+-------------------------------------------------------+
1 row in set (0.00 sec)

Suggested fix:
The patch attached to this ticket fixes the issue, but it's included to demonstrate the problem. More thought is required to determine how MySQL plans to address this and what the consequences are of keeping this function compliant.

Suggested fix

Attachment: patch_inetfunc.cc.patch (text/x-patch), 533 bytes.

Hi Aaditya Dubey,

Thank you for the test case. Verified as described.

Thank you very much for your patch contribution, we appreciate it!

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