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pair(4) interfaces patched together moves the configured inet address to wrong pair interface in resulting config

Open ryan-sg opened this issue 1 year ago • 2 comments

Hello!

Given the following config (daemon configs, pf, and crontab trimmed to save space, they were all defaults, just playing around with nsh)

EDIT: this is a VM with OpenBSD 7.5, not current

nshrc 

% The 'enable' command will switch to the root user.
% NSH v1.2.1-current; Compiled by [email protected] on 21-Jun-24 15:30
nshdev.localdomain/en
nshdev.localdomain(p)/show start
!
hostname nshdev.localdomain
!
motd rules
 OpenBSD 7.5 (GENERIC) #79: Wed Mar 20 15:33:49 MDT 2024
 OpenBSD: The proactively secure Unix-like operating system.
 Please use the sendbug(1) utility to report bugs in the system.
 Before reporting a bug, please try to reproduce it with the latest
 version of the code.  With bug reports, please try to ensure that
 enough information to reproduce the problem is enclosed, and if a
 known fix for it exists, include that as well.
!
interface lo0
 group lo
 inet ::1/128
 inet 127.0.0.1/8
!
interface vio0
 group egress
 inet 10.10.11.209/24
 media autoselect
!
interface vio1
 media autoselect
 shutdown
!
interface vio2
 media autoselect
 shutdown
!
interface vio3
 inet 10.2.1.1/29
 media autoselect
!
interface enc0
 group enc
 shutdown
!
interface pflog0
 group pflog
 no shutdown
!
interface lo2
 rdomain 2
 group lo
 shutdown
!
interface lo3
 rdomain 3
 group lo
 shutdown
!
!
ip forwarding
!
route 0.0.0.0/0 10.10.11.1 nompath
route 224.0.0.0/4 127.0.0.1 iface nompath reject
route 127.0.0.0/8 127.0.0.1 nompath reject
route ::/96 ::1 nompath reject
route ::ffff:0.0.0.0/96 ::1 nompath reject
route 2002::/24 ::1 nompath reject
route 2002:7f00::/24 ::1 nompath reject
route 2002:e000::/20 ::1 nompath reject
route 2002:ff00::/24 ::1 nompath reject
route fe80::/10 ::1 nompath reject
route fec0::/10 ::1 nompath reject
route ff01::/16 ::1 nompath reject
route ff02::/16 ::1 nompath reject
!
!
pf rules
!
pf enable
pf reload
!
snmp rules
!
resolv enable
!
ospf rules
!
ifstate rules
!
ntp rules
!
smtp rules
!
sshd rules
!
sshd enable
!
crontab rules
!
crontab install
rtable 1 
!
rtable 2 
!
rtable 3 
!
!

Upon creating some pair(4) interfaces to test using patch to switch between different rdomains on the fly, I noted that while the interfaces are created correctly, and function correctly, the generated config does not look correct.

Let's configure some pair(4)'s:

nshdev.localdomain(config-p)/interface pair0
nshdev.localdomain(interface-pair0)/inet 172.23.1.1/30
nshdev.localdomain(interface-pair0)/exit
nshdev.localdomain(config-p)/interface pair1
nshdev.localdomain(interface-pair1)/rdomain 2
nshdev.localdomain(interface-pair1)/inet 172.23.1.2/30
nshdev.localdomain(interface-pair1)/exit
nshdev.localdomain(config-p)/interface pair2
nshdev.localdomain(interface-pair2)/rdomain 3
nshdev.localdomain(interface-pair2)/inet 172.23.1.2/30
nshdev.localdomain(interface-pair2)/exit
nshdev.localdomain(config-p)/exit
nshdev.localdomain(p)/show diff
--- startup-config
+++ running-config
@@ -50,6 +50,25 @@
  group lo
  shutdown
 !
+interface pair0
+ group pair
+ inet 172.23.1.1/30
+ media autoselect
+!
+interface pair1
+ lladdr fe:e1:ba:d6:20:61
+ rdomain 2
+ group pair
+ inet 172.23.1.2/30
+ media autoselect
+!
+interface pair2
+ lladdr fe:e1:ba:d7:20:3a
+ rdomain 3
+ group pair
+ inet 172.23.1.2/30
+ media autoselect
+!
 !
 ip forwarding
 !

This looks good so far. We'll write it. Now we have:

interface pair0
 group pair
 inet 172.23.1.1/30
 media autoselect
!
interface pair1
 lladdr fe:e1:ba:d6:20:61
 rdomain 2
 group pair
 inet 172.23.1.2/30
 media autoselect
!
interface pair2
 lladdr fe:e1:ba:d7:20:3a
 rdomain 3
 group pair
 inet 172.23.1.2/30
 media autoselect
!
!

OK, all good! Let's patch one of them together:

nshdev.localdomain(config-p)/int pair0
nshdev.localdomain(interface-pair0)/patch pair1
nshdev.localdomain(interface-pair0)/end
% Invalid command
nshdev.localdomain(interface-pair0)/exit
nshdev.localdomain(config-p)/show diff
--- startup-config
+++ running-config
@@ -51,15 +51,17 @@
  shutdown
 !
 interface pair0
+ patch pair1
+ rdomain 2
  group pair
- inet 172.23.1.1/30
+ inet 172.23.1.2/30
  media autoselect
 !
 interface pair1
  lladdr fe:e1:ba:d6:20:61
- rdomain 2
+ patch pair0
  group pair
- inet 172.23.1.2/30
+ inet 172.23.1.1/30
  media autoselect
 !
 interface pair2

Hmm, this is odd, it swaps the inet address around. The resulting config ends up being:

interface pair0
 patch pair1
 rdomain 2
 group pair
 inet 172.23.1.2/30
 media autoselect
!
interface pair1
 lladdr fe:e1:ba:d6:20:61
 patch pair0
 group pair
 inet 172.23.1.1/30
 media autoselect
!
interface pair2
 lladdr fe:e1:ba:d7:20:3a
 rdomain 3
 group pair
 inet 172.23.1.2/30
 media autoselect
!

The actual interfaces end up looking like this:

% pair0
  Interface is up (last change 18d 19:38:35), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d0:cb:8b
  Media type autoselect, status active
  Internet address 172.23.1.1/30
  rdomain 0, MTU 1500 bytes (hardmtu 65435)
  27177 packets input, 7630011 bytes, 0 errors, 0 drops
  27743 packets output, 9416237 bytes, 0 errors, 0 unsupported
  280 input, 339 output (average bytes/packet)
  0 collisions
nshdev.localdomain(p)/show int pair1
% pair1
  Interface is up (last change 18d 19:37:57), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d2:78:e8
  Media type autoselect
  Internet address 172.23.1.2/30
  rdomain 2, MTU 1500 bytes (hardmtu 65435)
  13992 packets input, 4032844 bytes, 0 errors, 0 drops
  16679 packets output, 4295862 bytes, 0 errors, 0 unsupported
  288 input, 257 output (average bytes/packet)
  0 collisions
nshdev.localdomain(p)/show int pair2
% pair2
  Interface is up (last change 18d 19:37:48), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d2:78:e8
  Media type autoselect, status active
  Internet address 172.23.1.2/30
  rdomain 3, MTU 1500 bytes (hardmtu 65435)
  13750 packets input, 5383351 bytes, 0 errors, 0 drops
  20888 packets output, 4351753 bytes, 0 errors, 0 unsupported
  391 input, 208 output (average bytes/packet)
  0 collisions

When I originally noticed this, I took time to reconfigure inet addresses several times thinking i must have mucked up the ordering. But it appears the config renderer is doing it somehow, when trying to apply the patch argument to the participating interfaces.

So initial configuration works. You can even change between pair interfaces being patched, and things work. However, as expected, on reboot, the configuration then configures them with the wrong inet addresses:

% pair0
  Interface is up (last change 00:00:24), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d0:c4:af
  Media type autoselect, status active
  Internet address 172.23.1.2/30
  rdomain 2, MTU 1500 bytes (hardmtu 65435)
  1 packets input, 42 bytes, 0 errors, 0 drops
  1 packets output, 42 bytes, 0 errors, 0 unsupported
  0 collisions
nshdev.localdomain(p)/show int pair1
% pair1
  Interface is up (last change 00:00:26), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d6:20:61
  Media type autoselect, status active
  Internet address 172.23.1.1/30
  rdomain 0, MTU 1500 bytes (hardmtu 65435)
  0 packets input, 0 bytes, 0 errors, 0 drops
  1 packets output, 42 bytes, 0 errors, 0 unsupported
  0 collisions
nshdev.localdomain(p)/show int pair2
% pair2
  Interface is up (last change 00:00:27), protocol is up
  Interface type Ethernet (Broadcast), hardware address fe:e1:ba:d7:20:3a
  Media type autoselect
  Internet address 172.23.1.2/30
  rdomain 3, MTU 1500 bytes (hardmtu 65435)
  0 packets input, 0 bytes, 0 errors, 0 drops
  1 packets output, 42 bytes, 0 errors, 0 unsupported
  0 collisions

ryan-sg avatar Jul 08 '24 21:07 ryan-sg

Tom has confined this bug in 7.5 Current, patch command appears to swap the ips on the patched pair of interfaces workaround for now ... is to patch and un patch and patch again to (reverse x2 ) IP Swapping between the Patched pair of interface

smytht avatar Jul 09 '24 23:07 smytht

Tom can confirm that this is not an issue with OpenBSD / ifconfig pair patch (repeating the same steps as above with ifconfig in ksh does not exhibit the same bug. It is NSH specific

smytht avatar Jul 10 '24 13:07 smytht

Should be fixed with https://github.com/yellowman/nsh/pull/153

stspdotname avatar Aug 16 '24 16:08 stspdotname

Tested Stsps PR 153 and it works and resolves the issue PR 153 merged and issue resolved

smytht avatar Aug 16 '24 17:08 smytht