HelenOS sources

st_closing        502 uspace/srv/net/tcp/conn.c 	case st_closing:
st_closing        721 uspace/srv/net/tcp/conn.c 	case st_closing:
st_closing        989 uspace/srv/net/tcp/conn.c 	case st_closing:
st_closing       1038 uspace/srv/net/tcp/conn.c 	case st_closing:
st_closing       1142 uspace/srv/net/tcp/conn.c 			tcp_conn_state_set(conn, st_closing);
st_closing       1152 uspace/srv/net/tcp/conn.c 		case st_closing:
st_closing       1296 uspace/srv/net/tcp/conn.c 	case st_closing:
HelenOS homepage, sources at GitHub