[Bug 1529815] Re: InfiniBand DHCP flow with PRA and DHCP relay not working

Rafael David Tinoco rafael.tinoco at canonical.com
Wed Feb 10 13:52:51 UTC 2016


Last test I did was to see if IB DHCP would get the BROADCAST flag on IB
interfaces. It did. Now, I removed:

ip->client->config->bootp_broadcast_always = 1;

from setup_ib_interface (when preparing for DHCP REQUEST), so I could
check if the option:

bootp-broadcast-always

from the config file (added by this patch also) to check if it makes a
difference.

====

## without bootp-broadcast-always

tcpdump: listening on ib0, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes
13:34:47.376362 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
    0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request, length 300, htype 32, hlen 0, xid 0x5f7f9774, Flags [none] (0x0000)
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Discover
	    Hostname Option 12, length 5: "dixie"
	    Parameter-Request Option 55, length 13:
	      Subnet-Mask, BR, Time-Zone, Default-Gateway
	      Domain-Name, Domain-Name-Server, Option 119, Hostname
	      Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
	      NTP
	    Client-ID Option 61, length 17: hardware-type 56, 30:3a:30:30:3a:30:30:3a:34:38:3a:46:45:3a:38:30
	    END Option 255, length 0
	    PAD Option 0, length 0, occurs 15

## with bootp-broadcast-always

13:51:10.735292 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
    0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request, length 300, htype 32, hlen 0, xid 0x5bbf492d, Flags [Broadcast] (0x8000)
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Discover
	    Hostname Option 12, length 5: "dixie"
	    Parameter-Request Option 55, length 13:
	      Subnet-Mask, BR, Time-Zone, Default-Gateway
	      Domain-Name, Domain-Name-Server, Option 119, Hostname
	      Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
	      NTP
	    Client-ID Option 61, length 17: hardware-type 56, 30:3a:30:30:3a:30:30:3a:34:38:3a:46:45:3a:38:30
	    END Option 255, length 0
	    PAD Option 0, length 0, occurs 15

====

So the following statement in dhclient.conf

interface "ib0" {
    send dhcp-client-identifier = "80:00:00:48:FE:80";
    bootp-broadcast-always;
}

Is working good also.

-- 
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https://bugs.launchpad.net/bugs/1529815

Title:
  InfiniBand DHCP flow with PRA and DHCP relay not working

Status in isc-dhcp package in Ubuntu:
  In Progress

Bug description:
  
  DHCP client is sending discover with Unicast type request for the offer, in this configuration of IB to ETH through a relay we need the type to be broadcast.

  The issue is that when using dhclient from the client on Ubuntu (and only on Ubuntu) with MOFED or inbox driver, we see that that DHCP server offers in unicast instead of broadcast. It seems there is no way to correct this from the client side using dhclient configuration file.
  this issue exist even when we use always-broadcast statement in configuration file.

  in other vendors we see that discover request type is broadcast.
  attached pcap files from working (other vendor) and not working (Ubuntu) clients.

  
  DHCP CLIENT (IPoIB) 
  Ubuntu 14.04  kernel 3.13.0-74
  Mellanox OFED 3.1-1.0.3 or inbox driver
  isc-dhcp-client                  4.2.4-7ubuntu12.3

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