Foreword: As Wolfgang noted, Robin's emails apparently are being discarded by Sourceforge. I'm dual-subscribed - home and work - and only received emails from Robin on the email that was directly addressed to me.
Robin Getz wrote: > On Fri 11 Jul 2008 14:52, Jerry Van Baren pondered: >> Ben Warren wrote: >>> Robin Getz wrote: >>>> I was trying out U-Boot 1.1.3 with a new(er) router netgear WGR614v6 - >>>> firmware version V2.0.19_1.0.19NA, on a Blackfin BF537-STAMP. >>>> >>>> http://kbserver.netgear.com/products/wgr614v6.asp >>>> >>>> and found that dhcp fails :( >>>> bfin> dhcp >>>> BOOTP broadcast 1 >>>> BOOTP broadcast 2 >>>> BOOTP broadcast 3 >>>> BOOTP broadcast 4 >>>> BOOTP broadcast 5 >>>> >>>> Retry count exceeded; starting again >>>> >>>> When turning on some more verbose debug messages (in the net driver & in > the >>>> network code, not all of which exists in U-Boot release or trunk), we can > see >>>> exactly what is going on... >>>> >>>> ============================= >> First DHCP request... >> >>>> bfin> dhcp >>>> Eth_halt: ...... >>>> Eth_init: ...... >>>> BOOTP broadcast 1 >>>> setting transaction ID to 3268fe22 >>>> BFIN EMAC send: length = 343 >>>> BFIN EMAC rx: length = 552 >>>> packet received >>>> packet received >>>> Receive from protocol 0x800 >>>> Got IP >>>> len=308, v=45 >>>> passing packet len= 280 >>>> DHCPHandler: got packet: (src=67, dst=68, len=280) state: 3 >>>> Filtering pkt = 0 >>>> DHCPHandler: got DHCP packet: (src=67, dst=68, len=280) state: 3 >>>> DHCP: state=SELECTING bp_file: "" >>>> TRANSITIONING TO REQUESTING STATE >>>> IP was: 0.0.0.0 >>>> IP now: 192.168.0.9 >> ...worked. > > No - the DCHP server offered an address, When U-Boot does a DHCPREQUEST > (confirming it can have that address) it gets a DHCP NAK. Right. My confusion. >>>> Bootfile: >>>> DhcpSendRequestPkt: Sending DHCPREQUEST >> Why is the second DHCP request being sent? > > This is not a 2nd DHCP request being sent. This is part of the DHCP protocol. Right. My confusion. >> What is the second DHCP >> request asking for (sniff the net with wireshark). > > I can send you the wireshark file, but it is exactly as I described. > > http://www.ietf.org/rfc/rfc1533.txt > > Client sends DHCPDISCOVER > server sends DHCPOFFER > Client sends DHCPREQUEST > Server sends ARP > Client responds to ARP before it should > Server sends DHCPNAK, because someone on the network is using the IP number > (and doesn't bother to check the MAC - and notice that is the machine that it > just gave the IP number to). > Clients tosses the offer info (it did get NAKed), and starts over. RFC-1533 is "DHCP Options and BOOTP Vendor Extensions". RFC-2131 "Dynamic Host Configuration Protocol" appears to be the right RFC. The above sequence is somewhat odd and I would contend that it should be classified as a DHCP server bug. Quoting from RFC-2131: ------------------------------------------------------------------------- 2.2 Dynamic allocation of network addresses [snip] As a consistency check, the allocating server SHOULD probe the reused address *before* allocating the address, e.g., with an ICMP echo request, and the client SHOULD probe the newly received address, e.g., with ARP. ------------------------------------------------------------------------- My emphasis on the word *before*. The Netgear is apparently probing *after* allocating the IP address and then *withdrawing* it's allocation when u-boot (improperly) responds to the ARP (the ARP is probably is a side effect of a ICMP probe). This would explain why we have not been bitten by this bug before. Of course u-boot needs to abide by Postel's Prescription: "Be liberal in what you accept, and conservative in what you send." <http://www.postel.org/postel.html> IMHO, the Netgear WGR614v6 bug triggered a u-boot bug, for which we have a proposed/accepted (applied?) bug fix. [snip] Best regards, gvb ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ U-Boot-Users mailing list U-Boot-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/u-boot-users
