Short Term: * Merge listen.c functionality into hello.c. The intent is to feel like a "ping" utility. Use pthreads for the listener. * Add LLS block support. This will probably come as an lls.h file. * Remove getaddr and replace with ioctl calls to populate an ifreq struct. Moderate: * Support MD5 authentication. * Add Doxygen-compatible comments on every function and variable. Long: * Actually build adjacency with router and get topology table.