[Qemu-devel] [PATCH v2] qemu-options: add documentation for using UDP unicast network backend.

[Victor Kaplansky]

For the long time QEMU has support for UDP unicast network
backend added by commit 0e0e7facc775e9, but manual was missing
description and usage examples.

Changes from v1:

    Address comments by Michael S. Tsirkin:
      - remove superfluous empty lines.
      - place the note about two QEMU instances after the example.
      - English and others cleanups.

Signed-off-by: Victor Kaplansky <address@hidden>
---
 qemu-options.hx | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index 2485b94..6bdb884 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1907,6 +1907,28 @@ qemu-system-i386 linux.img \
                  -net socket,mcast=239.192.168.1:1102,localaddr=1.2.3.4
 @end example
 
address@hidden -netdev 
socket,address@hidden,address@hidden,address@hidden:@var{rport}[,address@hidden:@var{lport}]]
address@hidden -net 
socket[,address@hidden,address@hidden,address@hidden,address@hidden:@var{rport}[,address@hidden:@var{lport}]]
+
+Connect a VLAN @var{n} to a remote VLAN in another QEMU virtual
+machine using a UDP tunnel. Use lhost:lport as the local host and
+port, rhost:rport as the remote host and port of the tunnel.  Use
address@hidden to specify an already opened UDP socket.
+
+Example:
address@hidden
+# launch one QEMU instance
+qemu-system-i386 linux.img \
+                 -device virtio-net-pci,netdev=net0 \
+                 -netdev 
socket,id=net0,udp=localhost:4444,localaddr=localhost:5555
+# launch a second QEMU instance sharing the network with the first one
+qemu-system-i386 linux.img \
+                 -device virtio-net-pci,netdev=net0 \
+                 -netdev 
socket,id=net0,udp=localhost:5555,localaddr=localhost:4444
+
+NOTE: The two QEMU instances can be running on different hosts.
address@hidden example
+
 @item -netdev 
l2tpv3,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,ipv6][,udp][,cookie64][,counter][,pincounter][,address@hidden,address@hidden,address@hidden
 @itemx -net 
l2tpv3[,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,address@hidden,ipv6][,udp][,cookie64][,counter][,pincounter][,address@hidden,address@hidden,address@hidden
 Connect VLAN @var{n} to L2TPv3 pseudowire. L2TPv3 (RFC3391) is a popular
-- 
--Victor