From bfdb7ee65fc8b96f1fce10ef23871acb092b74b6 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 23 Nov 2020 08:32:41 +0100
Subject: [PATCH] urldata: remove 'void *protop' and create the union 'p'

... to avoid the use of 'void *' for the protocol specific structs done
per transfer.

Closes #6238

Upstream-Status: Backport [https://github.com/curl/curl/commit/a95a6ce6b809693a1195e3b4347a6cfa0fbc2ee7]

CVE: CVE-2020-8285

Signed-off-by: Daniel Stenberg <daniel@haxx.se>
Signed-off-by: Khairul Rohaizzat Jamaluddin <khairul.rohaizzat.jamaluddin@intel.com>

---
 docs/INTERNALS.md  |  4 ++--
 lib/file.c         | 14 +++++++-------
 lib/ftp.c          | 36 ++++++++++++++++++------------------
 lib/http.c         | 14 +++++++-------
 lib/http2.c        | 50 +++++++++++++++++++++++++-------------------------
 lib/http_proxy.c   |  6 +++---
 lib/imap.c         | 26 +++++++++++++-------------
 lib/mqtt.c         | 10 +++++-----
 lib/openldap.c     |  8 ++++----
 lib/pop3.c         | 14 +++++++-------
 lib/rtsp.c         |  8 ++++----
 lib/smb.c          | 20 ++++++++++----------
 lib/smtp.c         | 22 +++++++++++-----------
 lib/telnet.c       | 30 +++++++++++++++---------------
 lib/transfer.c     |  8 ++++----
 lib/url.c          |  2 +-
 lib/urldata.h      | 19 +++++++++++++++++--
 lib/vquic/ngtcp2.c | 24 ++++++++++++------------
 lib/vquic/quiche.c | 10 +++++-----
 lib/vssh/libssh.c  | 10 +++++-----
 lib/vssh/libssh2.c |  8 ++++----
 lib/vssh/wolfssh.c |  8 ++++----
 22 files changed, 183 insertions(+), 168 deletions(-)

diff --git a/docs/INTERNALS.md b/docs/INTERNALS.md
index 635e7b2..ca8988e 100644
--- a/docs/INTERNALS.md
+++ b/docs/INTERNALS.md
@@ -980,8 +980,8 @@ for older and later versions as things don't change drastically that often.
   protocol specific data that then gets associated with that `Curl_easy` for
   the rest of this transfer. It gets freed again at the end of the transfer.
   It will be called before the `connectdata` for the transfer has been
-  selected/created. Most protocols will allocate its private
-  `struct [PROTOCOL]` here and assign `Curl_easy->req.protop` to point to it.
+  selected/created. Most protocols will allocate its private `struct
+  [PROTOCOL]` here and assign `Curl_easy->req.p.[protocol]` to it.
 
   `->connect_it` allows a protocol to do some specific actions after the TCP
   connect is done, that can still be considered part of the connection phase.
diff --git a/lib/file.c b/lib/file.c
index cd3e49c..110e5c2 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -119,8 +119,8 @@ const struct Curl_handler Curl_handler_file = {
 static CURLcode file_setup_connection(struct connectdata *conn)
 {
   /* allocate the FILE specific struct */
-  conn->data->req.protop = calloc(1, sizeof(struct FILEPROTO));
-  if(!conn->data->req.protop)
+  conn->data->req.p.file = calloc(1, sizeof(struct FILEPROTO));
+  if(!conn->data->req.p.file)
     return CURLE_OUT_OF_MEMORY;
 
   return CURLE_OK;
@@ -135,7 +135,7 @@ static CURLcode file_connect(struct connectdata *conn, bool *done)
 {
   struct Curl_easy *data = conn->data;
   char *real_path;
-  struct FILEPROTO *file = data->req.protop;
+  struct FILEPROTO *file = data->req.p.file;
   int fd;
 #ifdef DOS_FILESYSTEM
   size_t i;
@@ -209,7 +209,7 @@ static CURLcode file_connect(struct connectdata *conn, bool *done)
 static CURLcode file_done(struct connectdata *conn,
                                CURLcode status, bool premature)
 {
-  struct FILEPROTO *file = conn->data->req.protop;
+  struct FILEPROTO *file = conn->data->req.p.file;
   (void)status; /* not used */
   (void)premature; /* not used */
 
@@ -227,7 +227,7 @@ static CURLcode file_done(struct connectdata *conn,
 static CURLcode file_disconnect(struct connectdata *conn,
                                 bool dead_connection)
 {
-  struct FILEPROTO *file = conn->data->req.protop;
+  struct FILEPROTO *file = conn->data->req.p.file;
   (void)dead_connection; /* not used */
 
   if(file) {
@@ -249,7 +249,7 @@ static CURLcode file_disconnect(struct connectdata *conn,
 
 static CURLcode file_upload(struct connectdata *conn)
 {
-  struct FILEPROTO *file = conn->data->req.protop;
+  struct FILEPROTO *file = conn->data->req.p.file;
   const char *dir = strchr(file->path, DIRSEP);
   int fd;
   int mode;
@@ -391,7 +391,7 @@ static CURLcode file_do(struct connectdata *conn, bool *done)
   if(data->set.upload)
     return file_upload(conn);
 
-  file = conn->data->req.protop;
+  file = conn->data->req.p.file;
 
   /* get the fd from the connection phase */
   fd = file->fd;
diff --git a/lib/ftp.c b/lib/ftp.c
index 9fadac5..d1a9447 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -1345,7 +1345,7 @@ static CURLcode ftp_state_use_pasv(struct connectdata *conn)
 static CURLcode ftp_state_prepare_transfer(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct Curl_easy *data = conn->data;
 
   if(ftp->transfer != FTPTRANSFER_BODY) {
@@ -1388,7 +1388,7 @@ static CURLcode ftp_state_prepare_transfer(struct connectdata *conn)
 static CURLcode ftp_state_rest(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   if((ftp->transfer != FTPTRANSFER_BODY) && ftpc->file) {
@@ -1409,7 +1409,7 @@ static CURLcode ftp_state_rest(struct connectdata *conn)
 static CURLcode ftp_state_size(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   if((ftp->transfer == FTPTRANSFER_INFO) && ftpc->file) {
@@ -1430,7 +1430,7 @@ static CURLcode ftp_state_list(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
 
   /* If this output is to be machine-parsed, the NLST command might be better
      to use, since the LIST command output is not specified or standard in any
@@ -1508,7 +1508,7 @@ static CURLcode ftp_state_stor_prequote(struct connectdata *conn)
 static CURLcode ftp_state_type(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct Curl_easy *data = conn->data;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
@@ -1565,7 +1565,7 @@ static CURLcode ftp_state_ul_setup(struct connectdata *conn,
                                    bool sizechecked)
 {
   CURLcode result = CURLE_OK;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct Curl_easy *data = conn->data;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
@@ -1664,7 +1664,7 @@ static CURLcode ftp_state_quote(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
   bool quote = FALSE;
   struct curl_slist *item;
@@ -2033,7 +2033,7 @@ static CURLcode ftp_state_mdtm_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   switch(ftpcode) {
@@ -2166,7 +2166,7 @@ static CURLcode ftp_state_retr(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   if(data->set.max_filesize && (filesize > data->set.max_filesize)) {
@@ -2378,7 +2378,7 @@ static CURLcode ftp_state_get_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
 
   if((ftpcode == 150) || (ftpcode == 125)) {
 
@@ -3138,7 +3138,7 @@ static CURLcode ftp_done(struct connectdata *conn, CURLcode status,
                          bool premature)
 {
   struct Curl_easy *data = conn->data;
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
   struct pingpong *pp = &ftpc->pp;
   ssize_t nread;
@@ -3492,7 +3492,7 @@ static CURLcode ftp_do_more(struct connectdata *conn, int *completep)
   bool complete = FALSE;
 
   /* the ftp struct is inited in ftp_connect() */
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
 
   /* if the second connection isn't done yet, wait for it */
   if(!conn->bits.tcpconnect[SECONDARYSOCKET]) {
@@ -3657,7 +3657,7 @@ CURLcode ftp_perform(struct connectdata *conn,
 
   if(conn->data->set.opt_no_body) {
     /* requested no body means no transfer... */
-    struct FTP *ftp = conn->data->req.protop;
+    struct FTP *ftp = conn->data->req.p.ftp;
     ftp->transfer = FTPTRANSFER_INFO;
   }
 
@@ -3692,7 +3692,7 @@ static void wc_data_dtor(void *ptr)
 static CURLcode init_wc_data(struct connectdata *conn)
 {
   char *last_slash;
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   char *path = ftp->path;
   struct WildcardData *wildcard = &(conn->data->wildcard);
   CURLcode result = CURLE_OK;
@@ -3826,7 +3826,7 @@ static CURLcode wc_statemach(struct connectdata *conn)
     /* filelist has at least one file, lets get first one */
     struct ftp_conn *ftpc = &conn->proto.ftpc;
     struct curl_fileinfo *finfo = wildcard->filelist.head->ptr;
-    struct FTP *ftp = conn->data->req.protop;
+    struct FTP *ftp = conn->data->req.p.ftp;
 
     char *tmp_path = aprintf("%s%s", wildcard->path, finfo->filename);
     if(!tmp_path)
@@ -4099,7 +4099,7 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
 {
   struct Curl_easy *data = conn->data;
   /* the ftp struct is already inited in ftp_connect() */
-  struct FTP *ftp = data->req.protop;
+  struct FTP *ftp = data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
   const char *slashPos = NULL;
   const char *fileName = NULL;
@@ -4244,7 +4244,7 @@ CURLcode ftp_parse_url_path(struct connectdata *conn)
 static CURLcode ftp_dophase_done(struct connectdata *conn,
                                  bool connected)
 {
-  struct FTP *ftp = conn->data->req.protop;
+  struct FTP *ftp = conn->data->req.p.ftp;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   if(connected) {
@@ -4341,7 +4341,7 @@ static CURLcode ftp_setup_connection(struct connectdata *conn)
   char *type;
   struct FTP *ftp;
 
-  conn->data->req.protop = ftp = calloc(sizeof(struct FTP), 1);
+  conn->data->req.p.ftp = ftp = calloc(sizeof(struct FTP), 1);
   if(NULL == ftp)
     return CURLE_OUT_OF_MEMORY;
 
diff --git a/lib/http.c b/lib/http.c
index 8fcdd43..31d9112 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -162,14 +162,14 @@ static CURLcode http_setup_conn(struct connectdata *conn)
      during this request */
   struct HTTP *http;
   struct Curl_easy *data = conn->data;
-  DEBUGASSERT(data->req.protop == NULL);
+  DEBUGASSERT(data->req.p.http == NULL);
 
   http = calloc(1, sizeof(struct HTTP));
   if(!http)
     return CURLE_OUT_OF_MEMORY;
 
   Curl_mime_initpart(&http->form, conn->data);
-  data->req.protop = http;
+  data->req.p.http = http;
 
   if(data->set.httpversion == CURL_HTTP_VERSION_3) {
     if(conn->handler->flags & PROTOPT_SSL)
@@ -425,7 +425,7 @@ static bool pickoneauth(struct auth *pick, unsigned long mask)
 static CURLcode http_perhapsrewind(struct connectdata *conn)
 {
   struct Curl_easy *data = conn->data;
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
   curl_off_t bytessent;
   curl_off_t expectsend = -1; /* default is unknown */
 
@@ -1109,7 +1109,7 @@ static size_t readmoredata(char *buffer,
                            void *userp)
 {
   struct connectdata *conn = (struct connectdata *)userp;
-  struct HTTP *http = conn->data->req.protop;
+  struct HTTP *http = conn->data->req.p.http;
   size_t fullsize = size * nitems;
 
   if(!http->postsize)
@@ -1167,7 +1167,7 @@ CURLcode Curl_buffer_send(struct dynbuf *in,
   char *ptr;
   size_t size;
   struct Curl_easy *data = conn->data;
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
   size_t sendsize;
   curl_socket_t sockfd;
   size_t headersize;
@@ -1517,7 +1517,7 @@ CURLcode Curl_http_done(struct connectdata *conn,
                         CURLcode status, bool premature)
 {
   struct Curl_easy *data = conn->data;
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
 
   /* Clear multipass flag. If authentication isn't done yet, then it will get
    * a chance to be set back to true when we output the next auth header */
@@ -1978,7 +1978,7 @@ CURLcode Curl_http(struct connectdata *conn, bool *done)
         return result;
     }
   }
-  http = data->req.protop;
+  http = data->req.p.http;
   DEBUGASSERT(http);
 
   if(!data->state.this_is_a_follow) {
diff --git a/lib/http2.c b/lib/http2.c
index d316da8..c41a1c2 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -257,7 +257,7 @@ static unsigned int http2_conncheck(struct connectdata *check,
 /* called from http_setup_conn */
 void Curl_http2_setup_req(struct Curl_easy *data)
 {
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
   http->bodystarted = FALSE;
   http->status_code = -1;
   http->pausedata = NULL;
@@ -391,7 +391,7 @@ char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
   if(!h || !GOOD_EASY_HANDLE(h->data))
     return NULL;
   else {
-    struct HTTP *stream = h->data->req.protop;
+    struct HTTP *stream = h->data->req.p.http;
     if(num < stream->push_headers_used)
       return stream->push_headers[num];
   }
@@ -413,7 +413,7 @@ char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
      !strcmp(header, ":") || strchr(header + 1, ':'))
     return NULL;
   else {
-    struct HTTP *stream = h->data->req.protop;
+    struct HTTP *stream = h->data->req.p.http;
     size_t len = strlen(header);
     size_t i;
     for(i = 0; i<stream->push_headers_used; i++) {
@@ -460,7 +460,7 @@ static struct Curl_easy *duphandle(struct Curl_easy *data)
       (void)Curl_close(&second);
     }
     else {
-      second->req.protop = http;
+      second->req.p.http = http;
       Curl_dyn_init(&http->header_recvbuf, DYN_H2_HEADERS);
       Curl_http2_setup_req(second);
       second->state.stream_weight = data->state.stream_weight;
@@ -537,7 +537,7 @@ static int push_promise(struct Curl_easy *data,
     /* ask the application */
     H2BUGF(infof(data, "Got PUSH_PROMISE, ask application!\n"));
 
-    stream = data->req.protop;
+    stream = data->req.p.http;
     if(!stream) {
       failf(data, "Internal NULL stream!\n");
       (void)Curl_close(&newhandle);
@@ -567,13 +567,13 @@ static int push_promise(struct Curl_easy *data,
     if(rv) {
       DEBUGASSERT((rv > CURL_PUSH_OK) && (rv <= CURL_PUSH_ERROROUT));
       /* denied, kill off the new handle again */
-      http2_stream_free(newhandle->req.protop);
-      newhandle->req.protop = NULL;
+      http2_stream_free(newhandle->req.p.http);
+      newhandle->req.p.http = NULL;
       (void)Curl_close(&newhandle);
       goto fail;
     }
 
-    newstream = newhandle->req.protop;
+    newstream = newhandle->req.p.http;
     newstream->stream_id = frame->promised_stream_id;
     newhandle->req.maxdownload = -1;
     newhandle->req.size = -1;
@@ -583,8 +583,8 @@ static int push_promise(struct Curl_easy *data,
     rc = Curl_multi_add_perform(data->multi, newhandle, conn);
     if(rc) {
       infof(data, "failed to add handle to multi\n");
-      http2_stream_free(newhandle->req.protop);
-      newhandle->req.protop = NULL;
+      http2_stream_free(newhandle->req.p.http);
+      newhandle->req.p.http = NULL;
       Curl_close(&newhandle);
       rv = CURL_PUSH_DENY;
       goto fail;
@@ -667,7 +667,7 @@ static int on_frame_recv(nghttp2_session *session, const nghttp2_frame *frame,
     return 0;
   }
 
-  stream = data_s->req.protop;
+  stream = data_s->req.p.http;
   if(!stream) {
     H2BUGF(infof(data_s, "No proto pointer for stream: %x\n",
                  stream_id));
@@ -783,7 +783,7 @@ static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
        internal error more than anything else! */
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
-  stream = data_s->req.protop;
+  stream = data_s->req.p.http;
   if(!stream)
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
@@ -849,7 +849,7 @@ static int on_stream_close(nghttp2_session *session, int32_t stream_id,
     }
     H2BUGF(infof(data_s, "on_stream_close(), %s (err %d), stream %u\n",
                  nghttp2_http2_strerror(error_code), error_code, stream_id));
-    stream = data_s->req.protop;
+    stream = data_s->req.p.http;
     if(!stream)
       return NGHTTP2_ERR_CALLBACK_FAILURE;
 
@@ -894,7 +894,7 @@ static int on_begin_headers(nghttp2_session *session,
     return 0;
   }
 
-  stream = data_s->req.protop;
+  stream = data_s->req.p.http;
   if(!stream || !stream->bodystarted) {
     return 0;
   }
@@ -952,7 +952,7 @@ static int on_header(nghttp2_session *session, const nghttp2_frame *frame,
        internal error more than anything else! */
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
-  stream = data_s->req.protop;
+  stream = data_s->req.p.http;
   if(!stream) {
     failf(data_s, "Internal NULL stream! 5\n");
     return NGHTTP2_ERR_CALLBACK_FAILURE;
@@ -1100,7 +1100,7 @@ static ssize_t data_source_read_callback(nghttp2_session *session,
          internal error more than anything else! */
       return NGHTTP2_ERR_CALLBACK_FAILURE;
 
-    stream = data_s->req.protop;
+    stream = data_s->req.p.http;
     if(!stream)
       return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
@@ -1161,7 +1161,7 @@ static void populate_settings(struct connectdata *conn,
 
 void Curl_http2_done(struct Curl_easy *data, bool premature)
 {
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
   struct http_conn *httpc = &data->conn->proto.httpc;
 
   /* there might be allocated resources done before this got the 'h2' pointer
@@ -1398,7 +1398,7 @@ CURLcode Curl_http2_done_sending(struct connectdata *conn)
      (conn->handler == &Curl_handler_http2)) {
     /* make sure this is only attempted for HTTP/2 transfers */
 
-    struct HTTP *stream = conn->data->req.protop;
+    struct HTTP *stream = conn->data->req.p.http;
 
     struct http_conn *httpc = &conn->proto.httpc;
     nghttp2_session *h2 = httpc->h2;
@@ -1522,7 +1522,7 @@ static void h2_pri_spec(struct Curl_easy *data,
                         nghttp2_priority_spec *pri_spec)
 {
   struct HTTP *depstream = (data->set.stream_depends_on?
-                            data->set.stream_depends_on->req.protop:NULL);
+                            data->set.stream_depends_on->req.p.http:NULL);
   int32_t depstream_id = depstream? depstream->stream_id:0;
   nghttp2_priority_spec_init(pri_spec, depstream_id, data->set.stream_weight,
                              data->set.stream_depends_e);
@@ -1539,7 +1539,7 @@ static void h2_pri_spec(struct Curl_easy *data,
 static int h2_session_send(struct Curl_easy *data,
                            nghttp2_session *h2)
 {
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   if((data->set.stream_weight != data->state.stream_weight) ||
      (data->set.stream_depends_e != data->state.stream_depends_e) ||
      (data->set.stream_depends_on != data->state.stream_depends_on) ) {
@@ -1569,7 +1569,7 @@ static ssize_t http2_recv(struct connectdata *conn, int sockindex,
   ssize_t nread;
   struct http_conn *httpc = &conn->proto.httpc;
   struct Curl_easy *data = conn->data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
 
   (void)sockindex; /* we always do HTTP2 on sockindex 0 */
 
@@ -1874,7 +1874,7 @@ static ssize_t http2_send(struct connectdata *conn, int sockindex,
    */
   int rv;
   struct http_conn *httpc = &conn->proto.httpc;
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
   nghttp2_nv *nva = NULL;
   size_t nheader;
   size_t i;
@@ -2183,7 +2183,7 @@ CURLcode Curl_http2_setup(struct connectdata *conn)
 {
   CURLcode result;
   struct http_conn *httpc = &conn->proto.httpc;
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
 
   DEBUGASSERT(conn->data->state.buffer);
 
@@ -2238,7 +2238,7 @@ CURLcode Curl_http2_switched(struct connectdata *conn,
   int rv;
   ssize_t nproc;
   struct Curl_easy *data = conn->data;
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
 
   result = Curl_http2_setup(conn);
   if(result)
@@ -2358,7 +2358,7 @@ CURLcode Curl_http2_stream_pause(struct Curl_easy *data, bool pause)
     return CURLE_OK;
 #ifdef NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE
   else {
-    struct HTTP *stream = data->req.protop;
+    struct HTTP *stream = data->req.p.http;
     struct http_conn *httpc = &data->conn->proto.httpc;
     uint32_t window = !pause * HTTP2_HUGE_WINDOW_SIZE;
     int rv = nghttp2_session_set_local_window_size(httpc->h2,
diff --git a/lib/http_proxy.c b/lib/http_proxy.c
index f188cbf..69aacb4 100644
--- a/lib/http_proxy.c
+++ b/lib/http_proxy.c
@@ -102,9 +102,9 @@ CURLcode Curl_proxy_connect(struct connectdata *conn, int sockindex)
      * This function might be called several times in the multi interface case
      * if the proxy's CONNECT response is not instant.
      */
-    prot_save = conn->data->req.protop;
+    prot_save = conn->data->req.p.http;
     memset(&http_proxy, 0, sizeof(http_proxy));
-    conn->data->req.protop = &http_proxy;
+    conn->data->req.p.http = &http_proxy;
     connkeep(conn, "HTTP proxy CONNECT");
 
     /* for the secondary socket (FTP), use the "connect to host"
@@ -125,7 +125,7 @@ CURLcode Curl_proxy_connect(struct connectdata *conn, int sockindex)
     else
       remote_port = conn->remote_port;
     result = Curl_proxyCONNECT(conn, sockindex, hostname, remote_port);
-    conn->data->req.protop = prot_save;
+    conn->data->req.p.http = prot_save;
     if(CURLE_OK != result)
       return result;
     Curl_safefree(data->state.aptr.proxyuserpwd);
diff --git a/lib/imap.c b/lib/imap.c
index cad0e59..bda23a5 100644
--- a/lib/imap.c
+++ b/lib/imap.c
@@ -244,7 +244,7 @@ static bool imap_matchresp(const char *line, size_t len, const char *cmd)
 static bool imap_endofresp(struct connectdata *conn, char *line, size_t len,
                            int *resp)
 {
-  struct IMAP *imap = conn->data->req.protop;
+  struct IMAP *imap = conn->data->req.p.imap;
   struct imap_conn *imapc = &conn->proto.imapc;
   const char *id = imapc->resptag;
   size_t id_len = strlen(id);
@@ -605,7 +605,7 @@ static CURLcode imap_perform_list(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
 
   if(imap->custom)
     /* Send the custom request */
@@ -640,7 +640,7 @@ static CURLcode imap_perform_select(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
   struct imap_conn *imapc = &conn->proto.imapc;
   char *mailbox;
 
@@ -679,7 +679,7 @@ static CURLcode imap_perform_select(struct connectdata *conn)
 static CURLcode imap_perform_fetch(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct IMAP *imap = conn->data->req.protop;
+  struct IMAP *imap = conn->data->req.p.imap;
   /* Check we have a UID */
   if(imap->uid) {
 
@@ -727,7 +727,7 @@ static CURLcode imap_perform_append(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
   char *mailbox;
 
   /* Check we have a mailbox */
@@ -797,7 +797,7 @@ static CURLcode imap_perform_append(struct connectdata *conn)
 static CURLcode imap_perform_search(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
-  struct IMAP *imap = conn->data->req.protop;
+  struct IMAP *imap = conn->data->req.p.imap;
 
   /* Check we have a query string */
   if(!imap->query) {
@@ -1051,7 +1051,7 @@ static CURLcode imap_state_select_resp(struct connectdata *conn, int imapcode,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = conn->data->req.protop;
+  struct IMAP *imap = conn->data->req.p.imap;
   struct imap_conn *imapc = &conn->proto.imapc;
   const char *line = data->state.buffer;
 
@@ -1380,7 +1380,7 @@ static CURLcode imap_init(struct connectdata *conn)
   struct Curl_easy *data = conn->data;
   struct IMAP *imap;
 
-  imap = data->req.protop = calloc(sizeof(struct IMAP), 1);
+  imap = data->req.p.imap = calloc(sizeof(struct IMAP), 1);
   if(!imap)
     result = CURLE_OUT_OF_MEMORY;
 
@@ -1457,7 +1457,7 @@ static CURLcode imap_done(struct connectdata *conn, CURLcode status,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
 
   (void)premature;
 
@@ -1517,7 +1517,7 @@ static CURLcode imap_perform(struct connectdata *conn, bool *connected,
   /* This is IMAP and no proxy */
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
   struct imap_conn *imapc = &conn->proto.imapc;
   bool selected = FALSE;
 
@@ -1640,7 +1640,7 @@ static CURLcode imap_disconnect(struct connectdata *conn, bool dead_connection)
 /* Call this when the DO phase has completed */
 static CURLcode imap_dophase_done(struct connectdata *conn, bool connected)
 {
-  struct IMAP *imap = conn->data->req.protop;
+  struct IMAP *imap = conn->data->req.p.imap;
 
   (void)connected;
 
@@ -1942,7 +1942,7 @@ static CURLcode imap_parse_url_path(struct connectdata *conn)
   /* The imap struct is already initialised in imap_connect() */
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
   const char *begin = &data->state.up.path[1]; /* skip leading slash */
   const char *ptr = begin;
 
@@ -2074,7 +2074,7 @@ static CURLcode imap_parse_custom_request(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct IMAP *imap = data->req.protop;
+  struct IMAP *imap = data->req.p.imap;
   const char *custom = data->set.str[STRING_CUSTOMREQUEST];
 
   if(custom) {
diff --git a/lib/mqtt.c b/lib/mqtt.c
index f6f4416..86b22b8 100644
--- a/lib/mqtt.c
+++ b/lib/mqtt.c
@@ -95,12 +95,12 @@ static CURLcode mqtt_setup_conn(struct connectdata *conn)
      during this request */
   struct MQTT *mq;
   struct Curl_easy *data = conn->data;
-  DEBUGASSERT(data->req.protop == NULL);
+  DEBUGASSERT(data->req.p.mqtt == NULL);
 
   mq = calloc(1, sizeof(struct MQTT));
   if(!mq)
     return CURLE_OUT_OF_MEMORY;
-  data->req.protop = mq;
+  data->req.p.mqtt = mq;
   return CURLE_OK;
 }
 
@@ -110,7 +110,7 @@ static CURLcode mqtt_send(struct connectdata *conn,
   CURLcode result = CURLE_OK;
   curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
   struct Curl_easy *data = conn->data;
-  struct MQTT *mq = data->req.protop;
+  struct MQTT *mq = data->req.p.mqtt;
   ssize_t n;
   result = Curl_write(conn, sockfd, buf, len, &n);
   if(!result && data->set.verbose)
@@ -426,7 +426,7 @@ static CURLcode mqtt_read_publish(struct connectdata *conn,
   unsigned char *pkt = (unsigned char *)data->state.buffer;
   size_t remlen;
   struct mqtt_conn *mqtt = &conn->proto.mqtt;
-  struct MQTT *mq = data->req.protop;
+  struct MQTT *mq = data->req.p.mqtt;
   unsigned char packet;
 
   switch(mqtt->state) {
@@ -533,7 +533,7 @@ static CURLcode mqtt_doing(struct connectdata *conn, bool *done)
   CURLcode result = CURLE_OK;
   struct mqtt_conn *mqtt = &conn->proto.mqtt;
   struct Curl_easy *data = conn->data;
-  struct MQTT *mq = data->req.protop;
+  struct MQTT *mq = data->req.p.mqtt;
   ssize_t nread;
   curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
   unsigned char *pkt = (unsigned char *)data->state.buffer;
diff --git a/lib/openldap.c b/lib/openldap.c
index 782d6a0..c955df6 100644
--- a/lib/openldap.c
+++ b/lib/openldap.c
@@ -410,7 +410,7 @@ static CURLcode ldap_do(struct connectdata *conn, bool *done)
   if(!lr)
     return CURLE_OUT_OF_MEMORY;
   lr->msgid = msgid;
-  data->req.protop = lr;
+  data->req.p.ldap = lr;
   Curl_setup_transfer(data, FIRSTSOCKET, -1, FALSE, -1);
   *done = TRUE;
   return CURLE_OK;
@@ -419,7 +419,7 @@ static CURLcode ldap_do(struct connectdata *conn, bool *done)
 static CURLcode ldap_done(struct connectdata *conn, CURLcode res,
                           bool premature)
 {
-  struct ldapreqinfo *lr = conn->data->req.protop;
+  struct ldapreqinfo *lr = conn->data->req.p.ldap;
 
   (void)res;
   (void)premature;
@@ -431,7 +431,7 @@ static CURLcode ldap_done(struct connectdata *conn, CURLcode res,
       ldap_abandon_ext(li->ld, lr->msgid, NULL, NULL);
       lr->msgid = 0;
     }
-    conn->data->req.protop = NULL;
+    conn->data->req.p.ldap = NULL;
     free(lr);
   }
 
@@ -443,7 +443,7 @@ static ssize_t ldap_recv(struct connectdata *conn, int sockindex, char *buf,
 {
   struct ldapconninfo *li = conn->proto.ldapc;
   struct Curl_easy *data = conn->data;
-  struct ldapreqinfo *lr = data->req.protop;
+  struct ldapreqinfo *lr = data->req.p.ldap;
   int rc, ret;
   LDAPMessage *msg = NULL;
   LDAPMessage *ent;
diff --git a/lib/pop3.c b/lib/pop3.c
index 9ff5c78..04cc887 100644
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -551,7 +551,7 @@ static CURLcode pop3_perform_command(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct POP3 *pop3 = data->req.protop;
+  struct POP3 *pop3 = data->req.p.pop3;
   const char *command = NULL;
 
   /* Calculate the default command */
@@ -884,7 +884,7 @@ static CURLcode pop3_state_command_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct POP3 *pop3 = data->req.protop;
+  struct POP3 *pop3 = data->req.p.pop3;
   struct pop3_conn *pop3c = &conn->proto.pop3c;
   struct pingpong *pp = &pop3c->pp;
 
@@ -1046,7 +1046,7 @@ static CURLcode pop3_init(struct connectdata *conn)
   struct Curl_easy *data = conn->data;
   struct POP3 *pop3;
 
-  pop3 = data->req.protop = calloc(sizeof(struct POP3), 1);
+  pop3 = data->req.p.pop3 = calloc(sizeof(struct POP3), 1);
   if(!pop3)
     result = CURLE_OUT_OF_MEMORY;
 
@@ -1120,7 +1120,7 @@ static CURLcode pop3_done(struct connectdata *conn, CURLcode status,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct POP3 *pop3 = data->req.protop;
+  struct POP3 *pop3 = data->req.p.pop3;
 
   (void)premature;
 
@@ -1154,7 +1154,7 @@ static CURLcode pop3_perform(struct connectdata *conn, bool *connected,
 {
   /* This is POP3 and no proxy */
   CURLcode result = CURLE_OK;
-  struct POP3 *pop3 = conn->data->req.protop;
+  struct POP3 *pop3 = conn->data->req.p.pop3;
 
   DEBUGF(infof(conn->data, "DO phase starts\n"));
 
@@ -1386,7 +1386,7 @@ static CURLcode pop3_parse_url_path(struct connectdata *conn)
 {
   /* The POP3 struct is already initialised in pop3_connect() */
   struct Curl_easy *data = conn->data;
-  struct POP3 *pop3 = data->req.protop;
+  struct POP3 *pop3 = data->req.p.pop3;
   const char *path = &data->state.up.path[1]; /* skip leading path */
 
   /* URL decode the path for the message ID */
@@ -1403,7 +1403,7 @@ static CURLcode pop3_parse_custom_request(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct POP3 *pop3 = data->req.protop;
+  struct POP3 *pop3 = data->req.p.pop3;
   const char *custom = data->set.str[STRING_CUSTOMREQUEST];
 
   /* URL decode the custom request */
diff --git a/lib/rtsp.c b/lib/rtsp.c
index dbd7dc6..29e6d58 100644
--- a/lib/rtsp.c
+++ b/lib/rtsp.c
@@ -114,7 +114,7 @@ static CURLcode rtsp_setup_connection(struct connectdata *conn)
 {
   struct RTSP *rtsp;
 
-  conn->data->req.protop = rtsp = calloc(1, sizeof(struct RTSP));
+  conn->data->req.p.rtsp = rtsp = calloc(1, sizeof(struct RTSP));
   if(!rtsp)
     return CURLE_OUT_OF_MEMORY;
 
@@ -199,7 +199,7 @@ static CURLcode rtsp_done(struct connectdata *conn,
                           CURLcode status, bool premature)
 {
   struct Curl_easy *data = conn->data;
-  struct RTSP *rtsp = data->req.protop;
+  struct RTSP *rtsp = data->req.p.rtsp;
   CURLcode httpStatus;
 
   /* Bypass HTTP empty-reply checks on receive */
@@ -232,7 +232,7 @@ static CURLcode rtsp_do(struct connectdata *conn, bool *done)
   struct Curl_easy *data = conn->data;
   CURLcode result = CURLE_OK;
   Curl_RtspReq rtspreq = data->set.rtspreq;
-  struct RTSP *rtsp = data->req.protop;
+  struct RTSP *rtsp = data->req.p.rtsp;
   struct dynbuf req_buffer;
   curl_off_t postsize = 0; /* for ANNOUNCE and SET_PARAMETER */
   curl_off_t putsize = 0; /* for ANNOUNCE and SET_PARAMETER */
@@ -764,7 +764,7 @@ CURLcode Curl_rtsp_parseheader(struct connectdata *conn,
     /* Store the received CSeq. Match is verified in rtsp_done */
     int nc = sscanf(&header[4], ": %ld", &CSeq);
     if(nc == 1) {
-      struct RTSP *rtsp = data->req.protop;
+      struct RTSP *rtsp = data->req.p.rtsp;
       rtsp->CSeq_recv = CSeq; /* mark the request */
       data->state.rtsp_CSeq_recv = CSeq; /* update the handle */
     }
diff --git a/lib/smb.c b/lib/smb.c
index d493adc..9eba7ab 100644
--- a/lib/smb.c
+++ b/lib/smb.c
@@ -204,7 +204,7 @@ static void conn_state(struct connectdata *conn, enum smb_conn_state newstate)
 static void request_state(struct connectdata *conn,
                           enum smb_req_state newstate)
 {
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
 #if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
   /* For debug purposes */
   static const char * const names[] = {
@@ -234,7 +234,7 @@ static CURLcode smb_setup_connection(struct connectdata *conn)
   struct smb_request *req;
 
   /* Initialize the request state */
-  conn->data->req.protop = req = calloc(1, sizeof(struct smb_request));
+  conn->data->req.p.smb = req = calloc(1, sizeof(struct smb_request));
   if(!req)
     return CURLE_OUT_OF_MEMORY;
 
@@ -342,7 +342,7 @@ static void smb_format_message(struct connectdata *conn, struct smb_header *h,
                                unsigned char cmd, size_t len)
 {
   struct smb_conn *smbc = &conn->proto.smbc;
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   unsigned int pid;
 
   memset(h, 0, sizeof(*h));
@@ -505,7 +505,7 @@ static CURLcode smb_send_tree_connect(struct connectdata *conn)
 
 static CURLcode smb_send_open(struct connectdata *conn)
 {
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   struct smb_nt_create msg;
   size_t byte_count;
 
@@ -535,7 +535,7 @@ static CURLcode smb_send_open(struct connectdata *conn)
 
 static CURLcode smb_send_close(struct connectdata *conn)
 {
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   struct smb_close msg;
 
   memset(&msg, 0, sizeof(msg));
@@ -556,7 +556,7 @@ static CURLcode smb_send_tree_disconnect(struct connectdata *conn)
 
 static CURLcode smb_send_read(struct connectdata *conn)
 {
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   curl_off_t offset = conn->data->req.offset;
   struct smb_read msg;
 
@@ -575,7 +575,7 @@ static CURLcode smb_send_read(struct connectdata *conn)
 static CURLcode smb_send_write(struct connectdata *conn)
 {
   struct smb_write *msg;
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   curl_off_t offset = conn->data->req.offset;
   curl_off_t upload_size = conn->data->req.size - conn->data->req.bytecount;
   CURLcode result = Curl_get_upload_buffer(conn->data);
@@ -738,7 +738,7 @@ static void get_posix_time(time_t *out, curl_off_t timestamp)
 
 static CURLcode smb_request_state(struct connectdata *conn, bool *done)
 {
-  struct smb_request *req = conn->data->req.protop;
+  struct smb_request *req = conn->data->req.p.smb;
   struct smb_header *h;
   struct smb_conn *smbc = &conn->proto.smbc;
   enum smb_req_state next_state = SMB_DONE;
@@ -923,7 +923,7 @@ static CURLcode smb_done(struct connectdata *conn, CURLcode status,
                          bool premature)
 {
   (void) premature;
-  Curl_safefree(conn->data->req.protop);
+  Curl_safefree(conn->data->req.p.smb);
   return status;
 }
 
@@ -957,7 +957,7 @@ static CURLcode smb_do(struct connectdata *conn, bool *done)
 static CURLcode smb_parse_url_path(struct connectdata *conn)
 {
   struct Curl_easy *data = conn->data;
-  struct smb_request *req = data->req.protop;
+  struct smb_request *req = data->req.p.smb;
   struct smb_conn *smbc = &conn->proto.smbc;
   char *path;
   char *slash;
diff --git a/lib/smtp.c b/lib/smtp.c
index aea41bb..c5d0296 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -484,7 +484,7 @@ static CURLcode smtp_perform_command(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
 
   if(smtp->rcpt) {
     /* We notify the server we are sending UTF-8 data if a) it supports the
@@ -697,7 +697,7 @@ static CURLcode smtp_perform_mail(struct connectdata *conn)
      any there do, as we need to correctly identify our support for SMTPUTF8
      in the envelope, as per RFC-6531 sect. 3.4 */
   if(conn->proto.smtpc.utf8_supported && !utf8) {
-    struct SMTP *smtp = data->req.protop;
+    struct SMTP *smtp = data->req.p.smtp;
     struct curl_slist *rcpt = smtp->rcpt;
 
     while(rcpt && !utf8) {
@@ -741,7 +741,7 @@ static CURLcode smtp_perform_rcpt_to(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   char *address = NULL;
   struct hostname host = { NULL, NULL, NULL, NULL };
 
@@ -989,7 +989,7 @@ static CURLcode smtp_state_command_resp(struct connectdata *conn, int smtpcode,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   char *line = data->state.buffer;
   size_t len = strlen(line);
 
@@ -1055,7 +1055,7 @@ static CURLcode smtp_state_rcpt_resp(struct connectdata *conn, int smtpcode,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   bool is_smtp_err = FALSE;
   bool is_smtp_blocking_err = FALSE;
 
@@ -1278,7 +1278,7 @@ static CURLcode smtp_init(struct connectdata *conn)
   struct Curl_easy *data = conn->data;
   struct SMTP *smtp;
 
-  smtp = data->req.protop = calloc(sizeof(struct SMTP), 1);
+  smtp = data->req.p.smtp = calloc(sizeof(struct SMTP), 1);
   if(!smtp)
     result = CURLE_OUT_OF_MEMORY;
 
@@ -1356,7 +1356,7 @@ static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   struct pingpong *pp = &conn->proto.smtpc.pp;
   char *eob;
   ssize_t len;
@@ -1442,7 +1442,7 @@ static CURLcode smtp_perform(struct connectdata *conn, bool *connected,
   /* This is SMTP and no proxy */
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
 
   DEBUGF(infof(conn->data, "DO phase starts\n"));
 
@@ -1550,7 +1550,7 @@ static CURLcode smtp_disconnect(struct connectdata *conn, bool dead_connection)
 /* Call this when the DO phase has completed */
 static CURLcode smtp_dophase_done(struct connectdata *conn, bool connected)
 {
-  struct SMTP *smtp = conn->data->req.protop;
+  struct SMTP *smtp = conn->data->req.p.smtp;
 
   (void)connected;
 
@@ -1703,7 +1703,7 @@ static CURLcode smtp_parse_custom_request(struct connectdata *conn)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   const char *custom = data->set.str[STRING_CUSTOMREQUEST];
 
   /* URL decode the custom request */
@@ -1796,7 +1796,7 @@ CURLcode Curl_smtp_escape_eob(struct connectdata *conn, const ssize_t nread)
   ssize_t i;
   ssize_t si;
   struct Curl_easy *data = conn->data;
-  struct SMTP *smtp = data->req.protop;
+  struct SMTP *smtp = data->req.p.smtp;
   char *scratch = data->state.scratch;
   char *newscratch = NULL;
   char *oldscratch = NULL;
diff --git a/lib/telnet.c b/lib/telnet.c
index c3b58e5..1fc5af1 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -247,7 +247,7 @@ CURLcode init_telnet(struct connectdata *conn)
   if(!tn)
     return CURLE_OUT_OF_MEMORY;
 
-  conn->data->req.protop = tn; /* make us known */
+  conn->data->req.p.telnet = tn; /* make us known */
 
   tn->telrcv_state = CURL_TS_DATA;
 
@@ -292,7 +292,7 @@ CURLcode init_telnet(struct connectdata *conn)
 static void negotiate(struct connectdata *conn)
 {
   int i;
-  struct TELNET *tn = (struct TELNET *) conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *) conn->data->req.p.telnet;
 
   for(i = 0; i < CURL_NTELOPTS; i++) {
     if(i == CURL_TELOPT_ECHO)
@@ -365,7 +365,7 @@ static void send_negotiation(struct connectdata *conn, int cmd, int option)
 static
 void set_remote_option(struct connectdata *conn, int option, int newstate)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   if(newstate == CURL_YES) {
     switch(tn->him[option]) {
     case CURL_NO:
@@ -439,7 +439,7 @@ void set_remote_option(struct connectdata *conn, int option, int newstate)
 static
 void rec_will(struct connectdata *conn, int option)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   switch(tn->him[option]) {
   case CURL_NO:
     if(tn->him_preferred[option] == CURL_YES) {
@@ -487,7 +487,7 @@ void rec_will(struct connectdata *conn, int option)
 static
 void rec_wont(struct connectdata *conn, int option)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   switch(tn->him[option]) {
   case CURL_NO:
     /* Already disabled */
@@ -529,7 +529,7 @@ void rec_wont(struct connectdata *conn, int option)
 static void
 set_local_option(struct connectdata *conn, int option, int newstate)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   if(newstate == CURL_YES) {
     switch(tn->us[option]) {
     case CURL_NO:
@@ -603,7 +603,7 @@ set_local_option(struct connectdata *conn, int option, int newstate)
 static
 void rec_do(struct connectdata *conn, int option)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   switch(tn->us[option]) {
   case CURL_NO:
     if(tn->us_preferred[option] == CURL_YES) {
@@ -663,7 +663,7 @@ void rec_do(struct connectdata *conn, int option)
 static
 void rec_dont(struct connectdata *conn, int option)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   switch(tn->us[option]) {
   case CURL_NO:
     /* Already disabled */
@@ -822,7 +822,7 @@ static CURLcode check_telnet_options(struct connectdata *conn)
   char option_keyword[128] = "";
   char option_arg[256] = "";
   struct Curl_easy *data = conn->data;
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   CURLcode result = CURLE_OK;
   int binary_option;
 
@@ -929,7 +929,7 @@ static void suboption(struct connectdata *conn)
   char varname[128] = "";
   char varval[128] = "";
   struct Curl_easy *data = conn->data;
-  struct TELNET *tn = (struct TELNET *)data->req.protop;
+  struct TELNET *tn = (struct TELNET *)data->req.p.telnet;
 
   printsub(data, '<', (unsigned char *)tn->subbuffer, CURL_SB_LEN(tn) + 2);
   switch(CURL_SB_GET(tn)) {
@@ -1004,7 +1004,7 @@ static void sendsuboption(struct connectdata *conn, int option)
   unsigned char *uc1, *uc2;
 
   struct Curl_easy *data = conn->data;
-  struct TELNET *tn = (struct TELNET *)data->req.protop;
+  struct TELNET *tn = (struct TELNET *)data->req.p.telnet;
 
   switch(option) {
   case CURL_TELOPT_NAWS:
@@ -1062,7 +1062,7 @@ CURLcode telrcv(struct connectdata *conn,
   int in = 0;
   int startwrite = -1;
   struct Curl_easy *data = conn->data;
-  struct TELNET *tn = (struct TELNET *)data->req.protop;
+  struct TELNET *tn = (struct TELNET *)data->req.p.telnet;
 
 #define startskipping()                                       \
   if(startwrite >= 0) {                                       \
@@ -1280,7 +1280,7 @@ static CURLcode send_telnet_data(struct connectdata *conn,
 static CURLcode telnet_done(struct connectdata *conn,
                                  CURLcode status, bool premature)
 {
-  struct TELNET *tn = (struct TELNET *)conn->data->req.protop;
+  struct TELNET *tn = (struct TELNET *)conn->data->req.p.telnet;
   (void)status; /* unused */
   (void)premature; /* not used */
 
@@ -1290,7 +1290,7 @@ static CURLcode telnet_done(struct connectdata *conn,
   curl_slist_free_all(tn->telnet_vars);
   tn->telnet_vars = NULL;
 
-  Curl_safefree(conn->data->req.protop);
+  Curl_safefree(conn->data->req.p.telnet);
 
   return CURLE_OK;
 }
@@ -1333,7 +1333,7 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done)
   if(result)
     return result;
 
-  tn = (struct TELNET *)data->req.protop;
+  tn = data->req.p.telnet;
 
   result = check_telnet_options(conn);
   if(result)
diff --git a/lib/transfer.c b/lib/transfer.c
index a07c7af..4630609 100644
--- a/lib/transfer.c
+++ b/lib/transfer.c
@@ -167,7 +167,7 @@ CURLcode Curl_fillreadbuffer(struct connectdata *conn, size_t bytes,
   bool sending_http_headers = FALSE;
 
   if(conn->handler->protocol&(PROTO_FAMILY_HTTP|CURLPROTO_RTSP)) {
-    const struct HTTP *http = data->req.protop;
+    const struct HTTP *http = data->req.p.http;
 
     if(http->sending == HTTPSEND_REQUEST)
       /* We're sending the HTTP request headers, not the data.
@@ -426,7 +426,7 @@ CURLcode Curl_readrewind(struct connectdata *conn)
      CURLOPT_HTTPPOST, call app to rewind
   */
   if(conn->handler->protocol & PROTO_FAMILY_HTTP) {
-    struct HTTP *http = data->req.protop;
+    struct HTTP *http = data->req.p.http;
 
     if(http->sendit)
       mimepart = http->sendit;
@@ -1028,7 +1028,7 @@ static CURLcode readwrite_upload(struct Curl_easy *data,
         /* HTTP pollution, this should be written nicer to become more
            protocol agnostic. */
         size_t fillcount;
-        struct HTTP *http = k->protop;
+        struct HTTP *http = k->p.http;
 
         if((k->exp100 == EXP100_SENDING_REQUEST) &&
            (http->sending == HTTPSEND_BODY)) {
@@ -1853,7 +1853,7 @@ Curl_setup_transfer(
 {
   struct SingleRequest *k = &data->req;
   struct connectdata *conn = data->conn;
-  struct HTTP *http = data->req.protop;
+  struct HTTP *http = data->req.p.http;
   bool httpsending = ((conn->handler->protocol&PROTO_FAMILY_HTTP) &&
                       (http->sending == HTTPSEND_REQUEST));
   DEBUGASSERT(conn != NULL);
diff --git a/lib/url.c b/lib/url.c
index 150667a..849d527 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -2060,7 +2060,7 @@ static CURLcode setup_connection_internals(struct connectdata *conn)
 
 void Curl_free_request_state(struct Curl_easy *data)
 {
-  Curl_safefree(data->req.protop);
+  Curl_safefree(data->req.p.http);
   Curl_safefree(data->req.newurl);
 
 #ifndef CURL_DISABLE_DOH
diff --git a/lib/urldata.h b/lib/urldata.h
index 0ae9269..76baee3 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -645,8 +645,23 @@ struct SingleRequest {
      and the 'upload_present' contains the number of bytes available at this
      position */
   char *upload_fromhere;
-  void *protop;       /* Allocated protocol-specific data. Each protocol
-                         handler makes sure this points to data it needs. */
+
+  /* Allocated protocol-specific data. Each protocol handler makes sure this
+     points to data it needs. */
+  union {
+    struct FILEPROTO *file;
+    struct FTP *ftp;
+    struct HTTP *http;
+    struct IMAP *imap;
+    struct ldapreqinfo *ldap;
+    struct MQTT *mqtt;
+    struct POP3 *pop3;
+    struct RTSP *rtsp;
+    struct smb_request *smb;
+    struct SMTP *smtp;
+    struct SSHPROTO *ssh;
+    struct TELNET *telnet;
+  } p;
 #ifndef CURL_DISABLE_DOH
   struct dohdata doh; /* DoH specific data for this request */
 #endif
diff --git a/lib/vquic/ngtcp2.c b/lib/vquic/ngtcp2.c
index 20ee08d..18eeda8 100644
--- a/lib/vquic/ngtcp2.c
+++ b/lib/vquic/ngtcp2.c
@@ -962,7 +962,7 @@ static int cb_h3_stream_close(nghttp3_conn *conn, int64_t stream_id,
                               void *stream_user_data)
 {
   struct Curl_easy *data = stream_user_data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   (void)conn;
   (void)stream_id;
   (void)app_error_code;
@@ -1008,7 +1008,7 @@ static int cb_h3_recv_data(nghttp3_conn *conn, int64_t stream_id,
                            void *user_data, void *stream_user_data)
 {
   struct Curl_easy *data = stream_user_data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   CURLcode result = CURLE_OK;
   (void)conn;
 
@@ -1067,7 +1067,7 @@ static int cb_h3_end_headers(nghttp3_conn *conn, int64_t stream_id,
                              void *user_data, void *stream_user_data)
 {
   struct Curl_easy *data = stream_user_data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   CURLcode result = CURLE_OK;
   (void)conn;
   (void)stream_id;
@@ -1091,7 +1091,7 @@ static int cb_h3_recv_header(nghttp3_conn *conn, int64_t stream_id,
   nghttp3_vec h3name = nghttp3_rcbuf_get_buf(name);
   nghttp3_vec h3val = nghttp3_rcbuf_get_buf(value);
   struct Curl_easy *data = stream_user_data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   CURLcode result = CURLE_OK;
   (void)conn;
   (void)stream_id;
@@ -1255,7 +1255,7 @@ static ssize_t ngh3_stream_recv(struct connectdata *conn,
                                 CURLcode *curlcode)
 {
   curl_socket_t sockfd = conn->sock[sockindex];
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
   struct quicsocket *qs = conn->quic;
 
   if(!stream->memlen) {
@@ -1313,7 +1313,7 @@ static int cb_h3_acked_stream_data(nghttp3_conn *conn, int64_t stream_id,
                                    void *stream_user_data)
 {
   struct Curl_easy *data = stream_user_data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   (void)conn;
   (void)stream_id;
   (void)user_data;
@@ -1335,7 +1335,7 @@ static ssize_t cb_h3_readfunction(nghttp3_conn *conn, int64_t stream_id,
 {
   struct Curl_easy *data = stream_user_data;
   size_t nread;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   (void)conn;
   (void)stream_id;
   (void)user_data;
@@ -1398,7 +1398,7 @@ static ssize_t cb_h3_readfunction(nghttp3_conn *conn, int64_t stream_id,
 static CURLcode http_request(struct connectdata *conn, const void *mem,
                              size_t len)
 {
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
   size_t nheader;
   size_t i;
   size_t authority_idx;
@@ -1641,7 +1641,7 @@ static ssize_t ngh3_stream_send(struct connectdata *conn,
   ssize_t sent;
   struct quicsocket *qs = conn->quic;
   curl_socket_t sockfd = conn->sock[sockindex];
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
 
   if(!stream->h3req) {
     CURLcode result = http_request(conn, mem, len);
@@ -1909,7 +1909,7 @@ CURLcode Curl_quic_done_sending(struct connectdata *conn)
 {
   if(conn->handler == &Curl_handler_http3) {
     /* only for HTTP/3 transfers */
-    struct HTTP *stream = conn->data->req.protop;
+    struct HTTP *stream = conn->data->req.p.http;
     struct quicsocket *qs = conn->quic;
     stream->upload_done = TRUE;
     (void)nghttp3_conn_resume_stream(qs->h3conn, stream->stream3_id);
@@ -1926,7 +1926,7 @@ void Curl_quic_done(struct Curl_easy *data, bool premature)
   (void)premature;
   if(data->conn->handler == &Curl_handler_http3) {
     /* only for HTTP/3 transfers */
-    struct HTTP *stream = data->req.protop;
+    struct HTTP *stream = data->req.p.http;
     Curl_dyn_free(&stream->overflow);
   }
 }
@@ -1941,7 +1941,7 @@ bool Curl_quic_data_pending(const struct Curl_easy *data)
      buffer and allocated an overflow buffer. Since it's possible that
      there's no more data coming on the socket, we need to keep reading
      until the overflow buffer is empty. */
-  const struct HTTP *stream = data->req.protop;
+  const struct HTTP *stream = data->req.p.http;
   return Curl_dyn_len(&stream->overflow) > 0;
 }
 
diff --git a/lib/vquic/quiche.c b/lib/vquic/quiche.c
index fd9cb8b..c0e250d 100644
--- a/lib/vquic/quiche.c
+++ b/lib/vquic/quiche.c
@@ -131,7 +131,7 @@ static unsigned int quiche_conncheck(struct connectdata *conn,
 
 static CURLcode quiche_do(struct connectdata *conn, bool *done)
 {
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
   stream->h3req = FALSE; /* not sent */
   return Curl_http(conn, done);
 }
@@ -460,7 +460,7 @@ static ssize_t h3_stream_recv(struct connectdata *conn,
   int rc;
   struct h3h1header headers;
   struct Curl_easy *data = conn->data;
-  struct HTTP *stream = data->req.protop;
+  struct HTTP *stream = data->req.p.http;
   headers.dest = buf;
   headers.destlen = buffersize;
   headers.nlen = 0;
@@ -548,7 +548,7 @@ static ssize_t h3_stream_send(struct connectdata *conn,
   ssize_t sent;
   struct quicsocket *qs = conn->quic;
   curl_socket_t sockfd = conn->sock[sockindex];
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
 
   if(!stream->h3req) {
     CURLcode result = http_request(conn, mem, len);
@@ -596,7 +596,7 @@ static CURLcode http_request(struct connectdata *conn, const void *mem,
 {
   /*
    */
-  struct HTTP *stream = conn->data->req.protop;
+  struct HTTP *stream = conn->data->req.p.http;
   size_t nheader;
   size_t i;
   size_t authority_idx;
@@ -824,7 +824,7 @@ CURLcode Curl_quic_done_sending(struct connectdata *conn)
   if(conn->handler == &Curl_handler_http3) {
     /* only for HTTP/3 transfers */
     ssize_t sent;
-    struct HTTP *stream = conn->data->req.protop;
+    struct HTTP *stream = conn->data->req.p.http;
     struct quicsocket *qs = conn->quic;
     fprintf(stderr, "!!! Curl_quic_done_sending\n");
     stream->upload_done = TRUE;
diff --git a/lib/vssh/libssh.c b/lib/vssh/libssh.c
index 8988e23..a84e1bf 100644
--- a/lib/vssh/libssh.c
+++ b/lib/vssh/libssh.c
@@ -662,7 +662,7 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SSHPROTO *protop = data->req.protop;
+  struct SSHPROTO *protop = data->req.p.ssh;
   struct ssh_conn *sshc = &conn->proto.sshc;
   curl_socket_t sock = conn->sock[FIRSTSOCKET];
   int rc = SSH_NO_ERROR, err;
@@ -2129,7 +2129,7 @@ static CURLcode myssh_setup_connection(struct connectdata *conn)
 {
   struct SSHPROTO *ssh;
 
-  conn->data->req.protop = ssh = calloc(1, sizeof(struct SSHPROTO));
+  conn->data->req.p.ssh = ssh = calloc(1, sizeof(struct SSHPROTO));
   if(!ssh)
     return CURLE_OUT_OF_MEMORY;
 
@@ -2152,7 +2152,7 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
   int rc;
 
   /* initialize per-handle data if not already */
-  if(!data->req.protop)
+  if(!data->req.p.ssh)
     myssh_setup_connection(conn);
 
   /* We default to persistent connections. We set this already in this connect
@@ -2353,7 +2353,7 @@ static CURLcode scp_disconnect(struct connectdata *conn,
 static CURLcode myssh_done(struct connectdata *conn, CURLcode status)
 {
   CURLcode result = CURLE_OK;
-  struct SSHPROTO *protop = conn->data->req.protop;
+  struct SSHPROTO *protop = conn->data->req.p.ssh;
 
   if(!status) {
     /* run the state-machine */
@@ -2606,7 +2606,7 @@ static void sftp_quote(struct connectdata *conn)
 {
   const char *cp;
   struct Curl_easy *data = conn->data;
-  struct SSHPROTO *protop = data->req.protop;
+  struct SSHPROTO *protop = data->req.p.ssh;
   struct ssh_conn *sshc = &conn->proto.sshc;
   CURLcode result;
 
diff --git a/lib/vssh/libssh2.c b/lib/vssh/libssh2.c
index 4f56bb4..3ed777f 100644
--- a/lib/vssh/libssh2.c
+++ b/lib/vssh/libssh2.c
@@ -789,7 +789,7 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
-  struct SSHPROTO *sftp_scp = data->req.protop;
+  struct SSHPROTO *sftp_scp = data->req.p.ssh;
   struct ssh_conn *sshc = &conn->proto.sshc;
   curl_socket_t sock = conn->sock[FIRSTSOCKET];
   int rc = LIBSSH2_ERROR_NONE;
@@ -2989,7 +2989,7 @@ static CURLcode ssh_setup_connection(struct connectdata *conn)
 {
   struct SSHPROTO *ssh;
 
-  conn->data->req.protop = ssh = calloc(1, sizeof(struct SSHPROTO));
+  conn->data->req.p.ssh = ssh = calloc(1, sizeof(struct SSHPROTO));
   if(!ssh)
     return CURLE_OUT_OF_MEMORY;
 
@@ -3013,7 +3013,7 @@ static CURLcode ssh_connect(struct connectdata *conn, bool *done)
   struct Curl_easy *data = conn->data;
 
   /* initialize per-handle data if not already */
-  if(!data->req.protop)
+  if(!data->req.p.ssh)
     ssh_setup_connection(conn);
 
   /* We default to persistent connections. We set this already in this connect
@@ -3192,7 +3192,7 @@ static CURLcode scp_disconnect(struct connectdata *conn, bool dead_connection)
 static CURLcode ssh_done(struct connectdata *conn, CURLcode status)
 {
   CURLcode result = CURLE_OK;
-  struct SSHPROTO *sftp_scp = conn->data->req.protop;
+  struct SSHPROTO *sftp_scp = conn->data->req.p.ssh;
 
   if(!status) {
     /* run the state-machine */
diff --git a/lib/vssh/wolfssh.c b/lib/vssh/wolfssh.c
index dcbbab6..1b990e3 100644
--- a/lib/vssh/wolfssh.c
+++ b/lib/vssh/wolfssh.c
@@ -322,7 +322,7 @@ static CURLcode wssh_setup_connection(struct connectdata *conn)
 {
   struct SSHPROTO *ssh;
 
-  conn->data->req.protop = ssh = calloc(1, sizeof(struct SSHPROTO));
+  conn->data->req.p.ssh = ssh = calloc(1, sizeof(struct SSHPROTO));
   if(!ssh)
     return CURLE_OUT_OF_MEMORY;
 
@@ -356,7 +356,7 @@ static CURLcode wssh_connect(struct connectdata *conn, bool *done)
   int rc;
 
   /* initialize per-handle data if not already */
-  if(!data->req.protop)
+  if(!data->req.p.ssh)
     wssh_setup_connection(conn);
 
   /* We default to persistent connections. We set this already in this connect
@@ -429,7 +429,7 @@ static CURLcode wssh_statemach_act(struct connectdata *conn, bool *block)
   CURLcode result = CURLE_OK;
   struct ssh_conn *sshc = &conn->proto.sshc;
   struct Curl_easy *data = conn->data;
-  struct SSHPROTO *sftp_scp = data->req.protop;
+  struct SSHPROTO *sftp_scp = data->req.p.ssh;
   WS_SFTPNAME *name;
   int rc = 0;
   *block = FALSE; /* we're not blocking by default */
@@ -1027,7 +1027,7 @@ static CURLcode wssh_block_statemach(struct connectdata *conn,
 static CURLcode wssh_done(struct connectdata *conn, CURLcode status)
 {
   CURLcode result = CURLE_OK;
-  struct SSHPROTO *sftp_scp = conn->data->req.protop;
+  struct SSHPROTO *sftp_scp = conn->data->req.p.ssh;
 
   if(!status) {
     /* run the state-machine */