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

Dave,

What do you mean by: "The Transparent Mode"?

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.__________/