[Commotion-dev] Can't talk between desktop OLSRd and Commotion OpenWRT boxes
Will Hawkins
hawkinsw at opentechinstitute.org
Tue Mar 26 17:23:33 UTC 2013
Sorry it's taken me so long to pipe up on this thread. I looked at that
patch that Ben/HC referenced. The fix that they applied definitely fixes
a problem. And, based on Ben's testing, it seems like it is the problem.
>From my reading, the way the code was written, it was working without
this patch only by chance. So, definitely a good one to include :-)
Will
On 03/19/2013 02:13 AM, Ben West wrote:
> I have been able to get a custom-compiled olsrd running now under my own
> instances of Ubuntu quantal, by applying this patch to src/net_olsr.c
> and then rebuilding the debs:
> https://lists.olsr.org/pipermail/olsr-dev/2012-June/005547.html
>
> This patch was referred to in the thread started by Hans on this topic
> in the olsr-dev listserv:
> https://lists.olsr.org/pipermail/olsr-dev/2013-March/006725.html
>
> Interestingly, the original bug was basically that olsrd was not sending
> outgoing packets out the wireless interface, instead failing with error
> message "sendto(v4): Invalid argument." The variables that are supposed
> to store the destination address for IPv4/6 packets, due to improper
> declaration, were being sometimes optimized away, depending on the gcc
> version and the optimization flags given. The patch mentioned above
> corrects the variables' declaration.
>
> It seems this particular bug has been fixed in newer versions of olsrd,
> but I'm guessing Canonical isn't going to be especially prompt about
> releasing an updated Ubuntu package.
>
> Could this patch be included in the guardianproject PPA for olsrd?
>
> On Mon, Mar 18, 2013 at 2:38 PM, Ben West <ben at gowasabi.net
> <mailto:ben at gowasabi.net>> wrote:
>
> Hi All,
>
> I'm having difficulty replicating this solution on my own platform
> (Ubuntu quantal i386 under a VMware host, but with real USB wifi radio).
>
> That is, removing the O2 compile option and recompiling olsrd does
> not seem to yield a working olsrd for me. I'm presently trying this
> out on a real host instead (i.e. no virtualization), but that is
> slowly opening a delightful can of worms w/r/t/ to thge newer
> Ubuntus dropping legacy video driver support and other such
> pleasantness.
>
> If the problem's source has been conclusively narrowed down to the
> -O2 (and even -fPIE?) flag added by Hans' patch
> 310-hardening-fixes.patch, could Hans just release an updated olsrd
> package in his PPA, with those flags removed, as an interim
> workaround for anyone not able to compile their own?
>
> On Sat, Mar 9, 2013 at 12:34 PM, Mikael Nordfeldth <mmn at hethane.se
> <mailto:mmn at hethane.se>> wrote:
>
> 2013-03-08 19:27, Hans-Christoph Steiner skrev:
> > That would be quite useful if you have the time! Another
> thing that might the
> > whole process easier is to 'git bisect', if you are familiar
> with that..
> > Right now, Debian squeeze and wheezy have 0.6.2, and Ubuntu
> has 0.6.1 and 0.6.3:
> >
> > http://packages.debian.org/search?keywords=olsrd
> > http://packages.ubuntu.com/search?keywords=olsrd
> >
> > So the idea is to find out which version of these we can rely
> on, and which we
> > need to use replacements.
>
> Gah. This seems way more advanced than what I can explain with my
> knowledge. Nevertheless, I did find what caused my error, the
> -O2 gcc
> optimization switch as patched by Debian package "hardening fixes":
>
> 1. I tried compiling various olsrd versions. All worked.
> 2. I tried compiling 0.6.3-5~quantal from 'apt-get source'. It
> didn't work.
> 3. I tried compiling the 0.6.3.orig source (same as above, without
> debian patches) It worked.
> 4. None of the patches contained any networking code (except the
> json
> plugin, but disabling it didn't have any effect anyway)
> 5. I found that removing the -O2 switch on line 227 in
> Makefile.inc, as
> patched by 310-hardening-fixes.patch resolved my invalid argument
> sendto(v4) issue:
>
> %.o: %.c
> @echo "[CC] $<"
> - $(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $<
> + $(CC) -O2 $(CFLAGS) $(CPPFLAGS) -fPIE -c -o $@ $<
>
>
> Reverting this (and even leaving the -fPIE there but removing
> -O2) makes
> the resulting binary functional.
>
>
> So the specific problem was caused by the -O2 parameter to gcc,
> I guess
> making it a compiling/linking issue. I don't know enough about this
> myself though, so I'm attaching ('O2-opts') the output of what that
> level of optimizations means if anyone is interested (gcc -c -Q -O2
> --help=optimizers)
>
> More info on my build environment is below:
>
> $ gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
> Target: x86_64-linux-gnu
> Configured with: ../src/configure -v
> --with-pkgversion='Ubuntu/Linaro
> 4.7.2-2ubuntu1'
> --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
> --enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
> --program-suffix=-4.7 --enable-shared --enable-linker-build-id
> --with-system-zlib --libexecdir=/usr/lib --without-included-gettext
> --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
> --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
> --enable-libstdcxx-debug --enable-libstdcxx-time=yes
> --enable-gnu-unique-object --enable-plugin --enable-objc-gc
> --disable-werror --with-arch-32=i686 --with-tune=generic
> --enable-checking=release --build=x86_64-linux-gnu
> --host=x86_64-linux-gnu --target=x86_64-linux-gnu
> Thread model: posix
> gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1)
>
>
> $ uname -a
> Linux plexi 3.5.0-25-generic #39-Ubuntu SMP Mon Feb 25 18:26:58
> UTC 2013
> x86_64 x86_64 x86_64 GNU/Linux
>
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>
> --
> Ben West
> http://gowasabi.net
> ben at gowasabi.net <mailto:ben at gowasabi.net>
> 314-246-9434 <tel:314-246-9434>
>
>
>
>
> --
> Ben West
> http://gowasabi.net
> ben at gowasabi.net <mailto:ben at gowasabi.net>
> 314-246-9434
>
>
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