Here are the data structures with brief descriptions:

Chttp_authentication_info_s	Structure for Authentication-Info header
Chttp_content_range_s	Content-Range
Chttp_cookie_s	Cookie
Chttp_date_s	Date, Expires, If-Modified-Since, If-Unmodified-Since, Last-Modified
Chttp_header_u	Union representing any HTTP header
Chttp_host_s	Host
Chttp_if_range_s	If-Range
Chttp_location_s	Location, Referer
Chttp_max_forwards_s	Max-Forwards
Chttp_range_s	Range
Chttp_request_s	HTTP request line
Chttp_retry_after_s	Retry-After
Chttp_s	HTTP message object
Chttp_set_cookie_s	Set-Cookie
Chttp_status_s	HTTP status line
Chttp_te_s	TE
Chttp_via_s	Via