lsof shows protocol: TCP

Question

I ran sudo lsof -p $(pidof foo) and I got a lot of these. Does anyone know what these represent? I know they come from the process but there are no ports / IP addresses.

COMMAND    PID USER   FD      TYPE             DEVICE  SIZE/OFF      NODE NAME
foo   115450 root  592u     sock                0,7       0t0 957442022 protocol: TCP
foo   115450 root  593u     sock                0,7       0t0 956964126 protocol: TCP
foo   115450 root  594u     sock                0,7       0t0 957091053 protocol: TCP
foo   115450 root  595u     sock                0,7       0t0 957498237 protocol: TCP
foo   115450 root  596u     sock                0,7       0t0 957077603 protocol: TCP
foo   115450 root  597u     sock                0,7       0t0 957211699 protocol: TCP

Answer 1

In case Stephen Harris's answer is deleted for being posted as a comment, I'm posting it as an answer:

Your application has created a socket (perhaps via socket(2)) in the TCP domain, but not bound it to any port (eg via connect(2) or listen(2) or bind(2)).

Answer 2

try to use strace with "-e trace=network" option to figure out which code is using sockets incorrectly. e.g,

[pid 16700] getsockopt(6, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
[pid 16700] getpeername(6, {sa_family=AF_INET, sin_port=htons(12345), 
 sin_addr=inet_addr("10.4.50.77")}, [112->16]) = 0
[pid 16700] getsockname(6, {sa_family=AF_INET, sin_port=htons(23456), 
 sin_addr=inet_addr("10.4.100.60")}, [112->16]) = 0
[pid 16700] setsockopt(6, SOL_TCP, TCP_NODELAY, [1], 4) = 0
[pid 16700] setsockopt(6, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
[pid 16700] setsockopt(6, SOL_TCP, TCP_KEEPINTVL, [15], 4) = 0
[pid 16700] setsockopt(6, SOL_TCP, TCP_KEEPIDLE, [15], 4) = 0