paclen

@Bug Bash / Thanks to Dave who has fixed the bug (also working on Xfbb) Thanks to Theo how has found the Bug.

There is an (apparently) very old bug in netromd of the linuxax25 tools. This bug ensures that nodes broadcasts on an AX.25 port with paclen <256 do not go out or are incomplete. This is the case in both the original and VE7FET versions.

Syslog get spammend with this kind of messages

Feb  6 14:20:03 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:08 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:13 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:18 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:23 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:28 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:33 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:38 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:20:43 raspberrypi netromd[17311]: netromt: sendto: Message too long
Feb  6 14:35:04 raspberrypi netromd[17320]: netromt: sendto: Message too long
Feb  6 14:35:09 raspberrypi netromd[17320]: netromt: sendto: Message too long
Feb  6 14:35:14 raspberrypi netromd[17320]: netromt: sendto: Message too long
Feb  6 14:35:19 raspberrypi netromd[17320]: netromt: sendto: Message too long

This can be fixed by releasing a patch on the ax25tools/netrom/netromt.c file.

106c106,111
< 
---
> 	int ax_paclen;
> 	
> 	ax_paclen = ax25_config_get_paclen (port_list[port].port);
> 	if (ax_paclen == 0) 
> 		ax_paclen = NODES_PACLEN;	
> 	
183,184c188,189
< 			if (len + ROUTE_LEN > NODES_PACLEN)
< 				break;
---
> 			if (len + ROUTE_LEN > ax_paclen)
> 				break;	
197,198c202,203
< 	/* If the packet was not full then we are done */
< 	} while (len + ROUTE_LEN > NODES_PACLEN);
---
> 	/* If the packet was not full then we are done */	
> 	} while (len + ROUTE_LEN > ax_paclen);

Download the patch

Let’s really uncomplicate these final two commands. I can bet on at least 40 letters from some of my friends and some users who are old-timers (or who think they are) giving me “the dickens” or a rebuttal about these next two commands. I’m about to simplify these two commands to the point of possible over-simplification. Over-simplification of a command is not to the liking of a few users.
They feel that because their early packet, days were difficult, so should be every one else’s. Νo one has more reason to complain about those days than I do, but who wants to complain? Even in those days we were having fun with packet.

The only difference between packet radio now and then is now we have more packeteers with whom to QSO, and the terminal program features have given us a medium that is far more than the “ΤYPE” and “SEND” system of six or seven years ago.

Now that the history lesson is over, let’s get to the PACLen setup of the TNC.
There are three simple rules for this command, and they are.

When using nodes or digipeaters on VHF, set PACLen 128 (normal default of most TNCs).
When usingdirectconnects, and with near perfect connect paths, set PACLen 255 (some TNCs accept PACL 0 as 255).
When operatingHFpacket, set PACLen 32 for300 b/s or PACLen 64 for 1200 b/s.

Tag: paclen

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