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NDN on Galileo

Building NDN

Building NDN for Galileo requires us to cross compile the main program on host machine and port it onto Galileo. We can't build ndn-cxx and nfd on Galileo, not just because it's slow but because Galileo has only 512K memory, while compiling ndn-cxx requires 2G memory.

Since boost is included in the image and toolchain (if you followed my steps in Building Galileo Image on Debian). In this section, we show how to cross compile libcryptopp, ndn-cxx, and nfd. There are alternative ways to compile libcryptopp and boost (please see remark).

On SDK machine

If you follow my instructions, your SDK should contain boost already. We shall install 3 more things here in SDK machine. Because NFD need a -pthread flag in LDFLAGS. We need to add it to our environment setup script. Note that if you use /opt/ndn or other directories outside your home directory on SDK machine, you may need to issue the following commands as a user with the appropriate permission, such as root.

cd /opt/ndn/
vim environment-setup-i586-poky-linux-uclibc

Append -pthread flag in LDFLAGS, so that the line becomes export LDFLAGS="-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -pthread" And then set up the environment

source environment-setup-i586-poky-linux-uclibc

1. libcryptopp

wget http://prdownloads.sourceforge.net/cryptopp/cryptopp562.zip
mkdir cryptopp
cd cryptopp
unzip ../cryptopp562.zip

There is a problem about libcryptopp's Makefile that prevents the make process from setting -march correctly. Please delete the following lines in GNUmakefile:

 39 ifeq ($(UNAME),Darwin)
 40 CXXFLAGS += -arch x86_64 -arch i386
 41 else
 42 CXXFLAGS += -march=native
 43 endif

These lines append -march=native to CXXFLAGS and therefore overwrite -march=i586 from environment-setup-i586-poky-linux-uclibc. After deleting these lines, the compiled libary should work.

make dynamic
make install PREFIX=$PKG_CONFIG_SYSROOT_DIR/usr

Because NDN requires only the dynamic library, we do make dynamic here. The value of PKG_CONFIG_SYSROOT_DIR was set when you executed source environment-setup-i586-poky-linux-uclibc, the value should be /opt/ndn/sysroots/i586-poky-linux-uclibc if you choose the same path as me for the toolchain directory.

2. ndn-cxx

cd /opt/ndn/

The ndn-cxx project use waf, which is a python tool, but if you simple type ./waf in ndn-cxx, it will report error because many python modules are missing in the cross compiler environment. Fortuantely, we don't actully need to compile and install python programs, we simply use python to compile ndn-cxx (which is a C++ program), so there is no need to use toolchain's python. Let's set the python environment to SDK machine's python.

export PYTHONHOME=/usr

Then install ndn-cxx, and remember to invoke the python on SDK machine

git clone https://github.com/named-data/ndn-cxx
cd ndn-cxx
/usr/bin/python waf configure --with-cryptopp=$PKG_CONFIG_SYSROOT_DIR/usr/ --boost-includes=$PKG_CONFIG_SYSROOT_DIR/usr/include/ --boost-libs=$PKG_CONFIG_SYSROOT_DIR/usr/lib/ --prefix=$PKG_CONFIG_SYSROOT_DIR/usr/
/usr/bin/python waf
/usr/bin/python waf install

3. nfd

cd /opt/ndn/
git clone --recursive https://github.com/named-data/NFD
cd NFD
/usr/bin/python waf configure --boost-includes=$PKG_CONFIG_SYSROOT_DIR/usr/include/ --boost-libs=$PKG_CONFIG_SYSROOT_DIR/usr/lib/ --prefix=$PKG_CONFIG_SYSROOT_DIR/usr/
/usr/bin/python waf
/usr/bin/python waf install

If you remember to add the -pthread to LDFLAGS in environment-setup-i586-poky-linux-uclibc, things should compile without error. If you did not follow my steps and encounter errors, the following are some of the possible errors and fixes:

  • Boost linkage error: in wscript, delete all tests to boost
  • snprintf not in std: In face/ethernet-face.cpp, change std::snprintf to snprintf, because in the toolchain, snprintf is not a member of std.
  • to_string not found: In tools/ndn-autoconfig/base-dns.cpp to_string change std::to_string to boost::chrono::to_string. This is because toolchain's library does not provide to_string, a C++11 function (toolchain's gcc does provide C++11 standard, but it just doesn't provide to_string).

Remark

We can compile libcryptopp and boost natively on Galileo, but the compilation takes a very long time.

  • There are three ways to install boost:

    1. boost is best installed by a recipe from the start (as I mentioned in Building Galileo Image on Debian), so that the toolchain contains boost from beginning.
    2. boost can now be installed natively in Galileo from Intel's IoT repository.
    3. Cross compile boost in the toolchain. It requires changing some lines in the make script of boost. boost uses somthing called bjam, which reads scripts written with its own language. The error is related to a wrong parameter type in a function call. The type was correct in normal compilation, but in cross compilation, extra flags in $CXX causes the error.
    4. Compile boost natively on Galileo. Tried it and succeeded. It took me 2.5 days, just waiting for the compilation.

  • For libcryptopp, there is no recipe, so we can cross compile it or compile it natively. Compile it natively takes only an hour, which isn't too bad.