Re: SVDM - strange issue "already connected"
By: deon to Digital Man on Fri Aug 04 2023 05:23 pm
Hey DM,
Not sure if you recall, but earlier this year I was having some problems with SVDM where after a while it would no longer connect.
Not sure if this is related, but I discovered a repeatable issue today.
In my svdm.ini file, I have an alias of
010003001=c-8-2.dege.lan:11179
That host resolves to both an IPv4 and IPv6 address. I think windows is prefering the IPv6 address when the resolver present both (although I'm not 100% sure if that is correct), but when I replace the hostname with an IPv4 address - the problem below does *not* occur. (So its either an IPv6 thing, or a resolver thing.)
Anyway, if when my (dos) mailer is calling to my uplink, and it gets a connection refused, the mailer (via SVDM) reports "NO CARRIER" (which I think is expected).
However, the next attempt results in SVDM reporting "ERROR" - regardless of whether the uplink is back online or not. If I try and call in to the mailer, I get SVDM responding "Sorry, not available right now".
Using dbgview, I can see each attempt.
The first failure:
00000049 5:08:15 PM [3472] SBBSVDM: RX command: ' ATD010003001 ' at 3035779
00000050 5:08:15 PM [3472] SBBSVDM: dial(010003001)
00000051 5:08:15 PM [3472] SBBSVDM: Connecting to port 11179 at host 'c-8-2.dege.lan' via Raw
00000052 5:08:15 PM [3472] SBBSVDM: C:\GitLab-Runner\builds\4S9KMgUy\2\main\sbbs\src\vdmodem\vdmodem.c 640 calling getaddrinfo
00000053 5:08:15 PM [3472] SBBSVDM: C:\GitLab-Runner\builds\4S9KMgUy\2\main\sbbs\src\vdmodem\vdmodem.c 662 calling connect
00000054 5:08:15 PM [3472] SBBSVDM: Setting socket options 00000055 5:08:15 PM [3472] SBBSVDM: Socket send buffer length: 8192 bytes
00000056 5:08:15 PM [3472] SBBSVDM: Socket receive buffer length: 8192 bytes
00000057 5:08:15 PM [3472] SBBSVDM: Socket TCP_NODELAY: 0 00000058 5:08:15 PM [3472] SBBSVDM: C:\GitLab-Runner\builds\4S9KMgUy\2\main\sbbs\src\vdmodem\vdmodem.c 710 socket_recvdone
00000059 5:08:15 PM [3472] SBBSVDM: Modem response: NO CARRIER
The subsequent failure:
00000070 5:08:23 PM [3472] SBBSVDM: RX command: ' ATD010003001 ' at 3043682
00000071 5:08:23 PM [3472] SBBSVDM: Can't dial: Already connected 00000072 5:08:23 PM [3472] SBBSVDM: Modem response: ERROR
IE: It is reporting "already connected" (when it isnt).
Thank you! That is very helpful.
The only way I can clear this is unload SVDM and reload it and then I'm good to go until next time the uplink (only 1 uplink tested) is offline.
Looking at the code, this is a bug, but I also think an "ATH0" would have cleared this condition.
Thought you might like to know.
(This is SVDM from 2a6d9983)
Thanks. I'll commit a fix in a second here, but nothing specifically for IPv6. Let me know if there remains some issue with the IPv6 support and I'll look into that.
--
digital man (rob)
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