Support of HTTP/1.0 and HTTP/0.9 #2405
Description
Currently, Tempesta FW supports HTTP/1.0 and HTTP/0.9. However, this code is not well covered by tests and appears incomplete. Supporting these protocols requires additional logic in the security and protocol layers. If they are not being used, it may be unnecessary to continue supporting them. We need to investigate whether anyone is using these protocols. If so, special attention should be paid to http_limits(for HTTP/0.9 this check is pointless). Also, note that HTTP/0.9 does not support headers and allows only a single method — GET. That requires addition handling and verification during request forwarding.
Another potential issue is the absence of a Host header in HTTP/1.0 requests. Tempesta FW supports only HTTP/1.1 for upstream connections, which requires a Host header. Forwarding an HTTP/1.0 request without a Host header seems pointless, as the most common behavior in this case is to return 400 error code.