add lsa packet
add ping packet
add ping.c and lsa.c
add ping_interval, ping_alpha and link_availability
minor update one output
remove hello thread
add sendNeighborReply
update LSA packet
keep sending packets
deal with different packets
remove port file when clean
minor updates
initial threadParam as global parameters
add LS DB part
use buffer to transfer data between server and client
add one comment
Merge branch 'master' of https://github.com/yuyuzhou-pitt/project