cc -Wall -O3 -g -I../include -c -o net.o net.c
net.c: In function ‘send_icmp’:
net.c:92: error: dereferencing pointer to incomplete type
net.c:105: error: dereferencing pointer to incomplete type
net.c:108: error: dereferencing pointer to incomplete type
net.c:109: error: dereferencing pointer to incomplete type
net.c:92: warning: unused variable ‘cbuf’
make[1]: *** [net.o] Error 1
