HTTP client: Minimal changes that include the improved API

This is a minimal version of pull request #15053 including all the
proposed improvements to the HTTP client API and its documentation
but only those code adaptations strictly needed for it.

The proposed new features include
* support for persistent connections (keep-alive),
* generalization to arbitrary request and response types, and
* support for streaming BIOs for request and response data.

The related API changes include:
* Split the monolithic OSSL_HTTP_transfer() into OSSL_HTTP_open(),
  OSSL_HTTP_set_request(), a lean OSSL_HTTP_transfer(), and OSSL_HTTP_close().
* Split the timeout functionality accordingly and improve default behavior.
* Extract part of OSSL_HTTP_REQ_CTX_new() to OSSL_HTTP_REQ_CTX_set_expected().

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15147)

1 files changed, 11 insertions, 14 deletions

diff --git a/crypto/ocsp/ocsp_http.c b/crypto/ocsp/ocsp_http.c
index 7a3c19c860..8cf816e53f 100644
--- a/crypto/ocsp/ocsp_http.c
+++ b/crypto/ocsp/ocsp_http.c
@@ -16,17 +16,18 @@
 OSSL_HTTP_REQ_CTX *OCSP_sendreq_new(BIO *io, const char *path,
                                     const OCSP_REQUEST *req, int maxline)
 {
-    OSSL_HTTP_REQ_CTX *rctx = NULL;
+    OSSL_HTTP_REQ_CTX *rctx = OSSL_HTTP_REQ_CTX_new(io, io, maxline);
 
-    if ((rctx = OSSL_HTTP_REQ_CTX_new(io, io,
-                                      maxline, 0 /* default max_resp_len */,
-                                      0 /* no timeout, blocking indefinitely */,
-                                      NULL, 1 /* expect_asn1 */)) == NULL)
+    if (rctx == NULL)
         return NULL;
 
     if (!OSSL_HTTP_REQ_CTX_set_request_line(rctx, 1 /* POST */, NULL, NULL, path))
         goto err;
 
+    if (!OSSL_HTTP_REQ_CTX_set_expected(rctx,
+                                        NULL /* content_type */, 1 /* asn1 */,
+                                        0 /* timeout */, 0 /* keep_alive */))
+        goto err;
     if (req != NULL
         && !OSSL_HTTP_REQ_CTX_set1_req(rctx, "application/ocsp-request",
                                        ASN1_ITEM_rptr(OCSP_REQUEST),
@@ -40,23 +41,19 @@ OSSL_HTTP_REQ_CTX *OCSP_sendreq_new(BIO *io, const char *path,
     return NULL;
 }
 
-int OCSP_sendreq_nbio(OCSP_RESPONSE **presp, OSSL_HTTP_REQ_CTX *rctx)
-{
-    *presp = (OCSP_RESPONSE *)
-        OSSL_HTTP_REQ_CTX_sendreq_d2i(rctx, ASN1_ITEM_rptr(OCSP_RESPONSE));
-    return *presp != NULL;
-}
-
 OCSP_RESPONSE *OCSP_sendreq_bio(BIO *b, const char *path, OCSP_REQUEST *req)
 {
     OCSP_RESPONSE *resp = NULL;
     OSSL_HTTP_REQ_CTX *ctx;
+    BIO *mem;
 
     ctx = OCSP_sendreq_new(b, path, req, -1 /* default max resp line length */);
     if (ctx == NULL)
         return NULL;
-
-    OCSP_sendreq_nbio(&resp, ctx);
+    mem = OSSL_HTTP_REQ_CTX_exchange(ctx);
+    resp = (OCSP_RESPONSE *)
+        ASN1_item_d2i_bio(ASN1_ITEM_rptr(OCSP_RESPONSE), mem, NULL);
+    BIO_free(mem);
 
     /* this indirectly calls ERR_clear_error(): */
     OSSL_HTTP_REQ_CTX_free(ctx);