Messages in this thread | | | From | Tom Gallagher <> | Subject | RE: Token Ring Bug (Broadcast and Multicast address check) | Date | Thu, 6 May 1999 17:23:10 +0100 |
| |
> > Hello! > > > byte with 0x80 and not 1 when checking for a broadcast or multicast > > address. > > Excellent! This puzzle bedevils me for year or so... > And nobody was able to give any intelligible answer 8) > > Let me one question to complete the picture: the same bit > of tr source address is TR_RII. Is it true? Do another magic > bits exist?
Yes this is true. Source addresses are always individual addresses so the individual/group bit used in the destination address is instead used to indicate source routing information in the source address. Other magic bits do exist:- In a destination address bit 6 (mask 0x40) of the first byte indicates a locally administered address (if 1). Also if both bit 7 and bit 6 are set (destination address starts with 0xC0) then bit 7 of the second address byte indicates whether the address is a group (1) or functional address (0).
> Also, could you write tr_header_parse routine to fetch > source address? (Look at eth_header_parse) > > BTW, could you send me piece of "tcpdump -p -e" with samples > of multicast packets originated by another hosts?
I'll look into this when I get time.
Thanks for the response.
from Tom
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |