{"id":1289,"date":"2011-06-19T22:54:22","date_gmt":"2011-06-20T02:54:22","guid":{"rendered":"http:\/\/www.braindeadprojects.com\/blog\/?p=1289"},"modified":"2011-06-19T22:54:22","modified_gmt":"2011-06-20T02:54:22","slug":"gns3-and-gentoo-fixing-qemu-networking","status":"publish","type":"post","link":"http:\/\/www.braindeadprojects.com\/blog\/what\/gns3-and-gentoo-fixing-qemu-networking\/","title":{"rendered":"GNS3 and Gentoo – fixing QEMU networking"},"content":{"rendered":"

I was hoping to have time to further familiarize myself with IPv6<\/a> this weekend –\u00a0 but workplace emergencies, sleep, and a technical glitch slowed me down. Here’s the story of the technical glitch.<\/p>\n

\"\"<\/a>
GNS3 - this thing rocks.<\/figcaption><\/figure>\n

GNS3<\/a>\/dynamips<\/a> can handle emulation of a number of routers, and I was happy to see that it can emulate host PCs as well. Unfortunately networking in GNS3\u00a0 is done via UDP tunnels<\/em> – something that requires a Qemu<\/a> patch to implement.<\/p>\n

\"\"<\/a>
For some reason QEMU won't really start if it's networked.<\/figcaption><\/figure>\n

In Gentoo<\/a>, simply building GNS3 from the Sunrise Overlay<\/a> doesn’t provide sufficient support for this requirement. Emulated routers (and I’m assuming switches) work fine when networked together. Emulated host machines work fine when NOT connected to anything. But once you network things together you’ll discover that your Qemu host won’t start.<\/p>\n

Here’s why – when you start a Qemu host, this is essentially what GNS3 runs:<\/p>\n

\/usr\/bin\/qemu -name QEMU1 -m 256 \/mnt\/virtualmachines\/dynips\/IPv6-tc\/working\/QEMU1\/FLASH -hdb \/mnt\/virtualmachines\/dynamips\/IPv6-tc\/working\/QEMU1\/SWAP -enable-kvm -net nic,vlan=0,macaddr=00:aa:00:8f:e4:00,model=rtl8139 -net udp,vlan=0,sport=20000,dport=10006,daddr=127.0.0.1 <\/strong>-net nic,vlan=1,macaddr=00:00:ab:fa:72:01,model=rtl8139 -serial telnet:127.0.0.1:3000,server,nowait -no-acpi -vnc :0<\/p><\/blockquote>\n

GNS3 attempts to use the -net udp<\/strong> option, something not offered in the default QEMU-KVM distribution. With no Gentoo USE flags<\/a> to add the patch in either 0.13.0 or 0.14.50, I decided to simply upgrade to 0.14.50 and see if it was part of the default build:<\/p>\n

# kvm –version
\nQEMU emulator version 0.14.50 (qemu-kvm-devel), Copyright (c) 2003-2008 Fabrice Bellard
\n# kvm –help | grep “net udp”
\n#<\/p><\/blockquote>\n

Nope, it’s not. So the next step is to remove app-emulation\/qemu-kvm from your system and build it by hand.<\/p>\n

First, remove kvm and download the source from kernel.org:<\/p>\n

# emerge -C app-emulation\/qemu-kvm<\/p>\n

# cd \/usr\/src\/<\/p>\n

# wget http:\/\/mirrors.kernel.org\/gentoo\/distfiles\/qemu-kvm-0.13.0.tar.gz<\/p><\/blockquote>\n

Unpack and patch it, using the patch provided by the gns-3 team <\/a>.<\/p>\n

# tar zxvpf qemu-kvm-0.13.0.tar.gz<\/p>\n

# cd qemu-kvm-0.13.0\/<\/p><\/blockquote>\n

Testing the patch, I ran into a handful of issues:<\/p>\n

# patch –dry-run -p1 < \/mnt\/nas\/downloads\/qemu-0.13.0-
\nmcast-udp.patch
\npatching file Makefile.objs
\nHunk #1 FAILED at 25.
\n1 out of 1 hunk FAILED — saving rejects to file Makefile.objs.rej
\npatching file block\/raw-win32.c
\nHunk #1 FAILED at 93.
\nHunk #2 FAILED at 347.
\n2 out of 2 hunks FAILED — saving rejects to file block\/raw-win32.c.rej
\npatching file hw\/e1000.c
\nHunk #1 FAILED at 567.
\n1 out of 1 hunk FAILED — saving rejects to file hw\/e1000.c.rej
\npatching file net\/udp.c
\npatching file net\/udp.h
\npatching file net.c
\nHunk #1 FAILED at 30.
\nHunk #2 FAILED at 1075.
\n2 out of 2 hunks FAILED — saving rejects to file net.c.rej
\npatching file net.h
\nHunk #1 FAILED at 33.
\n1 out of 1 hunk FAILED — saving rejects to file net.h.rej
\npatching file qemu-options.hx
\nHunk #1 FAILED at 996.
\n1 out of 1 hunk FAILED — saving rejects to file qemu-options.hx.rej<\/p><\/blockquote>\n

A quick modification and we’ve got a new patch file<\/a>. This one applies nicely:<\/p>\n

# patch –dry-run -p1 < \/mnt\/nas\/downloads\/gentoo-qemu-0.13.0.gns3.patch
\npatching file Makefile.objs
\npatching file QMP\/qmp-commands.txt
\npatching file block\/raw-win32.c
\npatching file config-all-devices.mak
\npatching file config-host.h
\npatching file config-host.h-timestamp
\npatching file config-host.ld
\npatching file config-host.mak
\npatching file hw\/e1000.c
\npatching file libdis\/config.mak
\npatching file libdis-user\/config.mak
\npatching file libhw32\/config.mak
\npatching file libhw64\/config.mak
\npatching file net\/udp.c
\npatching file net\/udp.h
\npatching file net.c
\npatching file net.h
\npatching file qemu-doc.html
\npatching file qemu-img-cmds.texi
\npatching file qemu-img.1
\npatching file qemu-monitor.texi
\npatching file qemu-nbd.8
\npatching file qemu-options.hx
\npatching file qemu-options.texi
\npatching file qemu-tech.html
\npatching file qemu.1
\npatching file roms\/seabios\/config.mak
\npatching file roms\/vgabios\/config.mak
\npatching file x86_64-softmmu\/config-devices.mak
\npatching file x86_64-softmmu\/config-devices.mak.old
\npatching file x86_64-softmmu\/config-target.mak
\nvonnegut qemu-kvm-0.13.0 #<\/p><\/blockquote>\n

So let’s apply it for real and then configure, build, and install our new Qemu:<\/p>\n

# patch -p1 < \/mnt\/nas\/downloads\/gentoo-qemu-0.13.0.gns3.patch<\/p>\n

…<\/p>\n

# .\/configure –prefix=\/usr –target-list=i386-softmmu –enable-sdl<\/p>\n

# make && make install<\/p><\/blockquote>\n

A quick check to ensure UDP tunneling is compiled in:<\/p>\n

# \/usr\/bin\/qemu –version
\nQEMU emulator version 0.13.0 (qemu-kvm-0.13.0), Copyright (c) 2003-2008 Fabrice Bellard
\n# \/usr\/bin\/qemu –help | grep “net udp”
\n-net udp[,vlan=n]sport=sport,dport=dport,daddr=host
\n#<\/p><\/blockquote>\n

And voila – now not only does my host machine start when networked into my layout, it also has connectivity:<\/p>\n

\"\"<\/a>
Yes, it finally works.<\/figcaption><\/figure>\n

Next up – continue lab work with IPv6, and begin studying for my CCNP<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

I was hoping to have time to further familiarize myself with IPv6 this weekend –\u00a0 but workplace emergencies, sleep, and a technical glitch slowed me down. Here’s the story of the technical glitch. GNS3\/dynamips can handle emulation of a number of routers, and I was happy to see that it can emulate host PCs as … Continue reading GNS3 and Gentoo – fixing QEMU networking<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,20,35,34,36,29,28,1],"tags":[],"class_list":["post-1289","post","type-post","status-publish","format-standard","hentry","category-braindeadtip","category-cisco","category-gns3","category-ipv6","category-kvm","category-linux","category-virtualization","category-what"],"_links":{"self":[{"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/posts\/1289"}],"collection":[{"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/comments?post=1289"}],"version-history":[{"count":53,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/posts\/1289\/revisions"}],"predecessor-version":[{"id":1346,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/posts\/1289\/revisions\/1346"}],"wp:attachment":[{"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/media?parent=1289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/categories?post=1289"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.braindeadprojects.com\/blog\/wp-json\/wp\/v2\/tags?post=1289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}