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, 20 insertions, 10 deletions

diff --git a/crypto/cmp/cmp_http.c b/crypto/cmp/cmp_http.c
index 215c47c7c5..a358622feb 100644
--- a/crypto/cmp/cmp_http.c
+++ b/crypto/cmp/cmp_http.c
@@ -37,9 +37,11 @@ OSSL_CMP_MSG *OSSL_CMP_MSG_http_perform(OSSL_CMP_CTX *ctx,
 {
     char server_port[32] = { '\0' };
     STACK_OF(CONF_VALUE) *headers = NULL;
-    const char *const content_type_pkix = "application/pkixcmp";
+    const char content_type_pkix[] = "application/pkixcmp";
     int tls_used;
-    OSSL_CMP_MSG *res;
+    const ASN1_ITEM *it = ASN1_ITEM_rptr(OSSL_CMP_MSG);
+    BIO *req_mem, *rsp;
+    OSSL_CMP_MSG *res = NULL;
 
     if (ctx == NULL || req == NULL) {
         ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);
@@ -48,6 +50,8 @@ OSSL_CMP_MSG *OSSL_CMP_MSG_http_perform(OSSL_CMP_CTX *ctx,
 
     if (!X509V3_add_value("Pragma", "no-cache", &headers))
         return NULL;
+    if ((req_mem = ASN1_item_i2d_mem_bio(it, (const ASN1_VALUE *)req)) == NULL)
+        goto err;
 
     if (ctx->serverPort != 0)
         BIO_snprintf(server_port, sizeof(server_port), "%d", ctx->serverPort);
@@ -55,15 +59,21 @@ OSSL_CMP_MSG *OSSL_CMP_MSG_http_perform(OSSL_CMP_CTX *ctx,
     tls_used = OSSL_CMP_CTX_get_http_cb_arg(ctx) != NULL;
     ossl_cmp_log2(DEBUG, ctx, "connecting to CMP server %s%s",
                   ctx->server, tls_used ? " using TLS" : "");
-    res = (OSSL_CMP_MSG *)
-        OSSL_HTTP_post_asn1(ctx->server, server_port, ctx->serverPath,
-                            tls_used, ctx->proxy, ctx->no_proxy, NULL, NULL,
-                            ctx->http_cb, OSSL_CMP_CTX_get_http_cb_arg(ctx),
-                            headers, content_type_pkix, (const ASN1_VALUE *)req,
-                            ASN1_ITEM_rptr(OSSL_CMP_MSG),
-                            0, 0, ctx->msg_timeout, content_type_pkix,
-                            ASN1_ITEM_rptr(OSSL_CMP_MSG));
+    rsp = OSSL_HTTP_transfer(NULL, ctx->server, server_port,
+                             ctx->serverPath, tls_used,
+                             ctx->proxy, ctx->no_proxy,
+                             NULL /* bio */, NULL /* rbio */,
+                             ctx->http_cb, OSSL_CMP_CTX_get_http_cb_arg(ctx),
+                             0 /* buf_size */, headers,
+                             content_type_pkix, req_mem,
+                             content_type_pkix, 1 /* expect_asn1 */,
+                             HTTP_DEFAULT_MAX_RESP_LEN,
+                             ctx->msg_timeout, 0 /* keep_alive */);
+    BIO_free(req_mem);
+    res = (OSSL_CMP_MSG *)ASN1_item_d2i_bio(it, rsp, NULL);
+    BIO_free(rsp);
     ossl_cmp_debug(ctx, "disconnected from CMP server");
+ err:
     sk_CONF_VALUE_pop_free(headers, X509V3_conf_free);
     return res;
 }