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

Tue Jul 19 16:24:00 UTC 2016

Verification for Xenial:

ubuntu at dixie:~$ uname -a
Linux dixie 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

ubuntu at dixie:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.1 LTS
Release:	16.04
Codename:	xenial

ubuntu at dixie:~$ dpkg -l | grep isc-dhcp
ii  isc-dhcp-client                    4.3.3-5ubuntu12.1               amd64        DHCP client for automatically obtaining an IP address
ii  isc-dhcp-common                    4.3.3-5ubuntu12.1               amd64        common files used by all of the isc-dhcp packages
ii  isc-dhcp-server                    4.3.3-5ubuntu12.1               amd64        ISC DHCP server for automatic IP address assignment

You can observe that DHCP works AND broadcast flag is set (by sniffing
dhcp server ib0 interface):

ubuntu at dixie:~$ sudo tcpdump -i ib0 -nn -vvv -S
tcpdump: listening on ib0, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
16:21:22.603191 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 0x6775c96f, Flags [Broadcast] (0x8000)
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Discover
	    Hostname Option 12, length 5: "hertz"
	    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
16:21:22.603401 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
    172.16.0.1.67 > 255.255.255.255.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, htype 32, hlen 0, xid 0x6775c96f, Flags [Broadcast] (0x8000)
	  Your-IP 172.16.0.19
	  Server-IP 172.16.0.1
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Offer
	    Server-ID Option 54, length 4: 172.16.0.1
	    Lease-Time Option 51, length 4: 600
	    Subnet-Mask Option 1, length 4: 255.255.255.0
	    BR Option 28, length 4: 172.16.0.255
	    Domain-Name Option 15, length 7: "myib.cu"
	    END Option 255, length 0
	    PAD Option 0, length 0, occurs 23
16:21:22.603586 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 0x6775c96f, Flags [Broadcast] (0x8000)
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: Request
	    Server-ID Option 54, length 4: 172.16.0.1
	    Requested-IP Option 50, length 4: 172.16.0.19
	    Hostname Option 12, length 5: "hertz"
	    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 3
16:21:22.603758 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
    172.16.0.1.67 > 255.255.255.255.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, htype 32, hlen 0, xid 0x6775c96f, Flags [Broadcast] (0x8000)
	  Your-IP 172.16.0.19
	  Server-IP 172.16.0.1
	  Vendor-rfc1048 Extensions
	    Magic Cookie 0x63825363
	    DHCP-Message Option 53, length 1: ACK
	    Server-ID Option 54, length 4: 172.16.0.1
	    Lease-Time Option 51, length 4: 600
	    Subnet-Mask Option 1, length 4: 255.255.255.0
	    BR Option 28, length 4: 172.16.0.255
	    Domain-Name Option 15, length 7: "myib.cu"
	    END Option 255, length 0
	    PAD Option 0, length 0, occurs 23

Everything looks good!!

** Tags removed: verification-needed
** Tags added: verification-done

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to isc-dhcp in Ubuntu.
https://bugs.launchpad.net/bugs/1529815

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

Status in isc-dhcp package in Ubuntu:
  Fix Released
Status in isc-dhcp source package in Trusty:
  In Progress
Status in isc-dhcp source package in Wily:
  Fix Committed
Status in isc-dhcp source package in Xenial:
  Fix Committed

Bug description:
  [Impact]

   * Infiniband users relying on DHCP can't use DHCP relay.

  [Test Case]

   * Comment #13
   * Mellanox has tested themselves.
   * Clear way of knowing if fix worked (tcpdump).

  [Regression Potential]

   * Only related to Infiniband.
   * Infiniband support could stop working (unlikely, already tested).

  [Other Info]

  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

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/1529815/+subscriptions