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* [Qemu-devel] [Bug 1838228] [NEW] Slirp Broadcast traffic
@ 2019-07-29  6:29 Chris Koch
  2019-07-29  7:59 ` [Qemu-devel] [Bug 1838228] " elmarco
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Chris Koch @ 2019-07-29  6:29 UTC (permalink / raw)
  To: qemu-devel

Public bug reported:

Hi all,

Version: QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-7+build1)

I'm running some DHCP traffic to a *custom* DHCP server with user-mode
networking in QEMU. I'm using port 30067 for the server, so this does
not conflict with the built-in DHCP server.

DHCP broadcasts to and from the server, and I'm observing issues with
both sending and receiving packets.

Firstly, from the VM, a packet sent to IPv4 x.x.x.2:30067 (gateway)
makes it to the server, but a packet sent to 255.255.255.255 does not.
I'd suspect that Slirp has to support sending to the broadcast IP
address? Or is this something I can turn on with a configuration option?
(My QEMU version too old?)

Secondly, the source address in a DHCP IPv4 packet must be 0.0.0.0 (by
RFC). That means that any return packet will have 0.0.0.0 swapped in as
its destination address. However, that packet doesn't make it into the
VM at all. I know that if you deliver this packet to Linux, a raw socket
will spit it back out. The packets' destination address should not
prevent the packet from being delivered to the right VM, since Slirp
(should?) know exactly which VM the session belongs to. (It's a proxy,
not a router.)

WDYT? Did I miss some configuration options or use too old a version?

Thanks,
Chris

** Affects: qemu
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1838228

Title:
  Slirp Broadcast traffic

Status in QEMU:
  New

Bug description:
  Hi all,

  Version: QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-7+build1)

  I'm running some DHCP traffic to a *custom* DHCP server with user-mode
  networking in QEMU. I'm using port 30067 for the server, so this does
  not conflict with the built-in DHCP server.

  DHCP broadcasts to and from the server, and I'm observing issues with
  both sending and receiving packets.

  Firstly, from the VM, a packet sent to IPv4 x.x.x.2:30067 (gateway)
  makes it to the server, but a packet sent to 255.255.255.255 does not.
  I'd suspect that Slirp has to support sending to the broadcast IP
  address? Or is this something I can turn on with a configuration
  option? (My QEMU version too old?)

  Secondly, the source address in a DHCP IPv4 packet must be 0.0.0.0 (by
  RFC). That means that any return packet will have 0.0.0.0 swapped in
  as its destination address. However, that packet doesn't make it into
  the VM at all. I know that if you deliver this packet to Linux, a raw
  socket will spit it back out. The packets' destination address should
  not prevent the packet from being delivered to the right VM, since
  Slirp (should?) know exactly which VM the session belongs to. (It's a
  proxy, not a router.)

  WDYT? Did I miss some configuration options or use too old a version?

  Thanks,
  Chris

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1838228/+subscriptions


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Qemu-devel] [Bug 1838228] Re: Slirp Broadcast traffic
  2019-07-29  6:29 [Qemu-devel] [Bug 1838228] [NEW] Slirp Broadcast traffic Chris Koch
@ 2019-07-29  7:59 ` elmarco
  2019-07-29 18:16 ` Chris Koch
  2021-04-22  7:15 ` Thomas Huth
  2 siblings, 0 replies; 4+ messages in thread
From: elmarco @ 2019-07-29  7:59 UTC (permalink / raw)
  To: qemu-devel

slirp has been moved to a standalone project, can you report here:
https://gitlab.freedesktop.org/slirp/libslirp/issues

I don't have an answer off the top of my head, but I would suggest
looking/tweaking at the network mask. And for the receive side,
debugging from sorecvfrom().

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1838228

Title:
  Slirp Broadcast traffic

Status in QEMU:
  New

Bug description:
  Hi all,

  Version: QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-7+build1)

  I'm running some DHCP traffic to a *custom* DHCP server with user-mode
  networking in QEMU. I'm using port 30067 for the server, so this does
  not conflict with the built-in DHCP server.

  DHCP broadcasts to and from the server, and I'm observing issues with
  both sending and receiving packets.

  Firstly, from the VM, a packet sent to IPv4 x.x.x.2:30067 (gateway)
  makes it to the server, but a packet sent to 255.255.255.255 does not.
  I'd suspect that Slirp has to support sending to the broadcast IP
  address? Or is this something I can turn on with a configuration
  option? (My QEMU version too old?)

  Secondly, the source address in a DHCP IPv4 packet must be 0.0.0.0 (by
  RFC). That means that any return packet will have 0.0.0.0 swapped in
  as its destination address. However, that packet doesn't make it into
  the VM at all. I know that if you deliver this packet to Linux, a raw
  socket will spit it back out. The packets' destination address should
  not prevent the packet from being delivered to the right VM, since
  Slirp (should?) know exactly which VM the session belongs to. (It's a
  proxy, not a router.)

  WDYT? Did I miss some configuration options or use too old a version?

  Thanks,
  Chris

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1838228/+subscriptions


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Qemu-devel] [Bug 1838228] Re: Slirp Broadcast traffic
  2019-07-29  6:29 [Qemu-devel] [Bug 1838228] [NEW] Slirp Broadcast traffic Chris Koch
  2019-07-29  7:59 ` [Qemu-devel] [Bug 1838228] " elmarco
@ 2019-07-29 18:16 ` Chris Koch
  2021-04-22  7:15 ` Thomas Huth
  2 siblings, 0 replies; 4+ messages in thread
From: Chris Koch @ 2019-07-29 18:16 UTC (permalink / raw)
  To: qemu-devel

Thanks. Opened https://gitlab.freedesktop.org/slirp/libslirp/issues/9.

** Bug watch added: gitlab.freedesktop.org/slirp/libslirp/issues #9
   https://gitlab.freedesktop.org/slirp/libslirp/issues/9

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1838228

Title:
  Slirp Broadcast traffic

Status in QEMU:
  New

Bug description:
  Hi all,

  Version: QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-7+build1)

  I'm running some DHCP traffic to a *custom* DHCP server with user-mode
  networking in QEMU. I'm using port 30067 for the server, so this does
  not conflict with the built-in DHCP server.

  DHCP broadcasts to and from the server, and I'm observing issues with
  both sending and receiving packets.

  Firstly, from the VM, a packet sent to IPv4 x.x.x.2:30067 (gateway)
  makes it to the server, but a packet sent to 255.255.255.255 does not.
  I'd suspect that Slirp has to support sending to the broadcast IP
  address? Or is this something I can turn on with a configuration
  option? (My QEMU version too old?)

  Secondly, the source address in a DHCP IPv4 packet must be 0.0.0.0 (by
  RFC). That means that any return packet will have 0.0.0.0 swapped in
  as its destination address. However, that packet doesn't make it into
  the VM at all. I know that if you deliver this packet to Linux, a raw
  socket will spit it back out. The packets' destination address should
  not prevent the packet from being delivered to the right VM, since
  Slirp (should?) know exactly which VM the session belongs to. (It's a
  proxy, not a router.)

  WDYT? Did I miss some configuration options or use too old a version?

  Thanks,
  Chris

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1838228/+subscriptions


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [Bug 1838228] Re: Slirp Broadcast traffic
  2019-07-29  6:29 [Qemu-devel] [Bug 1838228] [NEW] Slirp Broadcast traffic Chris Koch
  2019-07-29  7:59 ` [Qemu-devel] [Bug 1838228] " elmarco
  2019-07-29 18:16 ` Chris Koch
@ 2021-04-22  7:15 ` Thomas Huth
  2 siblings, 0 replies; 4+ messages in thread
From: Thomas Huth @ 2021-04-22  7:15 UTC (permalink / raw)
  To: qemu-devel

The ticket in the libslirp tracker has been closed a year ago, so I
think we can close this ticket here, too.

** Changed in: qemu
       Status: New => Fix Released

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1838228

Title:
  Slirp Broadcast traffic

Status in QEMU:
  Fix Released

Bug description:
  Hi all,

  Version: QEMU emulator version 3.1.0 (Debian 1:3.1+dfsg-7+build1)

  I'm running some DHCP traffic to a *custom* DHCP server with user-mode
  networking in QEMU. I'm using port 30067 for the server, so this does
  not conflict with the built-in DHCP server.

  DHCP broadcasts to and from the server, and I'm observing issues with
  both sending and receiving packets.

  Firstly, from the VM, a packet sent to IPv4 x.x.x.2:30067 (gateway)
  makes it to the server, but a packet sent to 255.255.255.255 does not.
  I'd suspect that Slirp has to support sending to the broadcast IP
  address? Or is this something I can turn on with a configuration
  option? (My QEMU version too old?)

  Secondly, the source address in a DHCP IPv4 packet must be 0.0.0.0 (by
  RFC). That means that any return packet will have 0.0.0.0 swapped in
  as its destination address. However, that packet doesn't make it into
  the VM at all. I know that if you deliver this packet to Linux, a raw
  socket will spit it back out. The packets' destination address should
  not prevent the packet from being delivered to the right VM, since
  Slirp (should?) know exactly which VM the session belongs to. (It's a
  proxy, not a router.)

  WDYT? Did I miss some configuration options or use too old a version?

  Thanks,
  Chris

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1838228/+subscriptions


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-04-22  7:27 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-29  6:29 [Qemu-devel] [Bug 1838228] [NEW] Slirp Broadcast traffic Chris Koch
2019-07-29  7:59 ` [Qemu-devel] [Bug 1838228] " elmarco
2019-07-29 18:16 ` Chris Koch
2021-04-22  7:15 ` Thomas Huth

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