tcpdump socket

Program output:
$ ./test
ICMP Reply, id=0x400, sequence =  0x100



Tcpdump output:
$ sudo tcpdump -i lo -X -v icmp
tcpdump: listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
15:13:55.398941 IP (tos 0x0, ttl 64, id 37644, offset 0, flags [DF], proto ICMP (1), length 28)
    localhost > localhost: ICMP echo request, id 4, seq 1, length 8
	0x0000:  4500 001c 930c 4000 4001 a9d2 7f00 0001  E.....@.@.......
	0x0010:  7f00 0001 0800 f7fa 0004 0001            ............
15:13:55.398958 IP (tos 0x0, ttl 64, id 37645, offset 0, flags [none], proto ICMP (1), length 28)
    localhost > localhost: ICMP echo reply, id 4, seq 1, length 8
	0x0000:  4500 001c 930d 0000 4001 e9d1 7f00 0001  E.......@.......
	0x0010:  7f00 0001 0000 fffa 0004 0001            ............