Re: LDL Driver: cannot send to arbitrary LLC (802.2) DSAP

At 10:45 AM 9/16/2004, Tim Brown wrote:
>Dave,
>
>What do you mean by: "The Transparent Mode"?

I don't have time to give you the cookbook, but if you look at the ldl 
driver (and, who knows, perhaps even its documentation) there are different 
modes of operation that are controlled by how you do the dl_attach.  One is 
a transparent mode in which your driver gets to see all of the incoming 
Ethernet packets.

-- Dave


>tim
>
>Dave Grothe wrote:
>>I have been using the transparent mode in order to avoid this kind of 
>>thing.  My driver does its own filtering of addresses and SAPs.
>>-- Dave
>>At 09:33 AM 9/16/2004, Tim Brown wrote:
>>
>>>I am porting some network multiplexor software which uses multiplexes
>>>messages between hosts and processes on hosts using 802.2 DSAP/SSAP
>>>addressing.
>>>
>>>I bind onto a DSAP, allowing me to listen for Ethernet frames addressed
>>>to me. Within those packets is the return address for me to send my replies
>>>to. This may or may not be the Ethernet address of the sender.
>>>
>>>I then wish to send a frame to the destination which may have an arbitrary
>>>DSAP. However, in eth_8022_mkhdr() in drivers/str/linux/ldl.c line:1704
>>>
>>>         if (dsap != dl->sap->sap.sap[0]) {
>>>                 struct sap *sap;
>>>
>>>                 for (sap = dl->subs; sap; sap = sap->next_sap)
>>>                         if (dsap == sap->sap.sap[0])
>>>                                 break;
>>>                 if (sap == NULL)
>>>                         return 0;
>>>         }
>>>
>>>i.e. if you are not bound to "dsap", or have an additional binding
>>>      to "dsap", then the message isn't sent.
>>>
>>>I am using LiS 2.17.U.
>>>
>>>I don't believe this behaviour is correct, since it is inconsistent
>>>with the Solaris and AIX DLPI drivers, as well as the understanding
>>>of most people here of how DSAP/SSAP addressing works; i.e. you bind
>>>onto and listen on a DSAP (or multiple DSAPs), but any process on any
>>>station can transmit to any of the available SSAPs.
>>>
>>>Therefore, I don't believe there is any reason for this code. Is there?
>>>
>>>Regards,
>>>
>>>Tim
>>>
>>>--
>>>Tim Brown <[email protected]> |            City Computing Limited |
>>>T: +44 20 8770 2110               |      City House, Sutton Park Road |
>>>F: +44 20 8770 2130               |       Sutton, Surrey, SM1 2AE, GB |
>>>BEAUTY: What's in your eye when you have a bee in your hand.__________/
>>>
>>>_______________________________________________
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>
>--
>Tim Brown <[email protected]> |            City Computing Limited |
>T: +44 20 8770 2110               |      City House, Sutton Park Road |
>F: +44 20 8770 2130               |       Sutton, Surrey, SM1 2AE, GB |
>BEAUTY: What's in your eye when you have a bee in your hand.__________/
>
>_______________________________________________
>Linux-streams mailing list
>[email protected]
>http://gsyc.escet.urjc.es/mailman/listinfo/linux-streams