From 8335c6417ea21bdfc340f0cb8cab5dbc97b10a2e Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 20 Jan 2021 10:15:43 +0100
Subject: [PATCH] hostip: remove conn->data from resolver functions

This also moves the 'async' struct from the connectdata struct into the
Curl_easy struct, which seems like a better home for it.

Closes #6497
---
 lib/asyn-ares.c     | 132 +++++++++++++++++++++----------------------
 lib/asyn-thread.c   | 135 ++++++++++++++++++++++----------------------
 lib/asyn.h          |  14 ++---
 lib/connect.c       |   4 +-
 lib/doh.c           |  15 +++--
 lib/doh.h           |   6 +-
 lib/easy.c          |   4 +-
 lib/ftp.c           |  12 ++--
 lib/hostasyn.c      |  20 +++----
 lib/hostip.c        |  63 ++++++++++-----------
 lib/hostip.h        |  15 +++--
 lib/hostip4.c       |   6 +-
 lib/hostip6.c       |   9 +--
 lib/multi.c         |  12 ++--
 lib/socks.c         |  16 +++---
 lib/url.c           |  12 ++--
 lib/urldata.h       |  19 ++++---
 tests/data/test1082 |   2 +-
 18 files changed, 242 insertions(+), 254 deletions(-)

diff --git a/lib/asyn-ares.c b/lib/asyn-ares.c
index c17cd265b3..2484a7b498 100644
--- a/lib/asyn-ares.c
+++ b/lib/asyn-ares.c
@@ -204,22 +204,22 @@ static void destroy_async_data(struct Curl_async *async);
 /*
  * Cancel all possibly still on-going resolves for this connection.
  */
-void Curl_resolver_cancel(struct connectdata *conn)
+void Curl_resolver_cancel(struct Curl_easy *data)
 {
-  if(conn->data && conn->data->state.resolver)
-    ares_cancel((ares_channel)conn->data->state.resolver);
-  destroy_async_data(&conn->async);
+  if(data && data->state.async.resolver)
+    ares_cancel((ares_channel)data->state.async.resolver);
+  destroy_async_data(&data->state.async);
 }
 
 /*
  * We're equivalent to Curl_resolver_cancel() for the c-ares resolver.  We
  * never block.
  */
-void Curl_resolver_kill(struct connectdata *conn)
+void Curl_resolver_kill(struct Curl_easy *data)
 {
   /* We don't need to check the resolver state because we can be called safely
      at any time and we always do the same thing. */
-  Curl_resolver_cancel(conn);
+  Curl_resolver_cancel(data);
 }
 
 /*
@@ -253,25 +253,25 @@ static void destroy_async_data(struct Curl_async *async)
  * Returns: sockets-in-use-bitmap
  */
 
-int Curl_resolver_getsock(struct connectdata *conn,
+int Curl_resolver_getsock(struct Curl_easy *data,
                           curl_socket_t *socks)
 {
   struct timeval maxtime;
   struct timeval timebuf;
   struct timeval *timeout;
   long milli;
-  int max = ares_getsock((ares_channel)conn->data->state.resolver,
+  int max = ares_getsock((ares_channel)data->state.async.resolver,
                          (ares_socket_t *)socks, MAX_SOCKSPEREASYHANDLE);
 
   maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
   maxtime.tv_usec = 0;
 
-  timeout = ares_timeout((ares_channel)conn->data->state.resolver, &maxtime,
+  timeout = ares_timeout((ares_channel)data->state.async.resolver, &maxtime,
                          &timebuf);
   milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000);
   if(milli == 0)
     milli += 10;
-  Curl_expire(conn->data, milli, EXPIRE_ASYNC_NAME);
+  Curl_expire(data, milli, EXPIRE_ASYNC_NAME);
 
   return max;
 }
@@ -286,9 +286,8 @@ int Curl_resolver_getsock(struct connectdata *conn,
  * return number of sockets it worked on
  */
 
-static int waitperform(struct connectdata *conn, timediff_t timeout_ms)
+static int waitperform(struct Curl_easy *data, timediff_t timeout_ms)
 {
-  struct Curl_easy *data = conn->data;
   int nfds;
   int bitmask;
   ares_socket_t socks[ARES_GETSOCK_MAXNUM];
@@ -296,7 +295,7 @@ static int waitperform(struct connectdata *conn, timediff_t timeout_ms)
   int i;
   int num = 0;
 
-  bitmask = ares_getsock((ares_channel)data->state.resolver, socks,
+  bitmask = ares_getsock((ares_channel)data->state.async.resolver, socks,
                          ARES_GETSOCK_MAXNUM);
 
   for(i = 0; i < ARES_GETSOCK_MAXNUM; i++) {
@@ -324,12 +323,12 @@ static int waitperform(struct connectdata *conn, timediff_t timeout_ms)
   if(!nfds)
     /* Call ares_process() unconditonally here, even if we simply timed out
        above, as otherwise the ares name resolve won't timeout! */
-    ares_process_fd((ares_channel)data->state.resolver, ARES_SOCKET_BAD,
+    ares_process_fd((ares_channel)data->state.async.resolver, ARES_SOCKET_BAD,
                     ARES_SOCKET_BAD);
   else {
     /* move through the descriptors and ask for processing on them */
     for(i = 0; i < num; i++)
-      ares_process_fd((ares_channel)data->state.resolver,
+      ares_process_fd((ares_channel)data->state.async.resolver,
                       (pfd[i].revents & (POLLRDNORM|POLLIN))?
                       pfd[i].fd:ARES_SOCKET_BAD,
                       (pfd[i].revents & (POLLWRNORM|POLLOUT))?
@@ -345,17 +344,16 @@ static int waitperform(struct connectdata *conn, timediff_t timeout_ms)
  *
  * Returns normal CURLcode errors.
  */
-CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
+CURLcode Curl_resolver_is_resolved(struct Curl_easy *data,
                                    struct Curl_dns_entry **dns)
 {
-  struct Curl_easy *data = conn->data;
-  struct thread_data *res = conn->async.tdata;
+  struct thread_data *res = data->state.async.tdata;
   CURLcode result = CURLE_OK;
 
   DEBUGASSERT(dns);
   *dns = NULL;
 
-  waitperform(conn, 0);
+  waitperform(data, 0);
 
   /* Now that we've checked for any last minute results above, see if there are
      any responses still pending when the EXPIRE_HAPPY_EYEBALLS_DNS timer
@@ -376,26 +374,27 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
        ARES_ECANCELLED synchronously for all pending responses.  This will
        leave us with res->num_pending == 0, which is perfect for the next
        block. */
-    ares_cancel((ares_channel)data->state.resolver);
+    ares_cancel((ares_channel)data->state.async.resolver);
     DEBUGASSERT(res->num_pending == 0);
   }
 
   if(res && !res->num_pending) {
-    (void)Curl_addrinfo_callback(conn, res->last_status, res->temp_ai);
+    (void)Curl_addrinfo_callback(data, res->last_status, res->temp_ai);
     /* temp_ai ownership is moved to the connection, so we need not free-up
        them */
     res->temp_ai = NULL;
 
-    if(!conn->async.dns) {
+    if(!data->state.async.dns) {
       failf(data, "Could not resolve: %s (%s)",
-            conn->async.hostname, ares_strerror(conn->async.status));
-      result = conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
+            data->state.async.hostname,
+            ares_strerror(data->state.async.status));
+      result = data->conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
         CURLE_COULDNT_RESOLVE_HOST;
     }
     else
-      *dns = conn->async.dns;
+      *dns = data->state.async.dns;
 
-    destroy_async_data(&conn->async);
+    destroy_async_data(&data->state.async);
   }
 
   return result;
@@ -412,11 +411,10 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
  * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved,
  * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  */
-CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
+CURLcode Curl_resolver_wait_resolv(struct Curl_easy *data,
                                    struct Curl_dns_entry **entry)
 {
   CURLcode result = CURLE_OK;
-  struct Curl_easy *data = conn->data;
   timediff_t timeout;
   struct curltime now = Curl_now();
 
@@ -426,7 +424,7 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
   timeout = Curl_timeleft(data, &now, TRUE);
   if(timeout < 0) {
     /* already expired! */
-    connclose(conn, "Timed out before name resolve started");
+    connclose(data->conn, "Timed out before name resolve started");
     return CURLE_OPERATION_TIMEDOUT;
   }
   if(!timeout)
@@ -447,7 +445,7 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
     store.tv_sec = itimeout/1000;
     store.tv_usec = (itimeout%1000)*1000;
 
-    tvp = ares_timeout((ares_channel)data->state.resolver, &store, &tv);
+    tvp = ares_timeout((ares_channel)data->state.async.resolver, &store, &tv);
 
     /* use the timeout period ares returned to us above if less than one
        second is left, otherwise just use 1000ms to make sure the progress
@@ -457,10 +455,10 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
     else
       timeout_ms = 1000;
 
-    waitperform(conn, timeout_ms);
-    result = Curl_resolver_is_resolved(conn, entry);
+    waitperform(data, timeout_ms);
+    result = Curl_resolver_is_resolved(data, entry);
 
-    if(result || conn->async.done)
+    if(result || data->state.async.done)
       break;
 
     if(Curl_pgrsUpdate(data))
@@ -481,17 +479,17 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
   }
   if(result)
     /* failure, so we cancel the ares operation */
-    ares_cancel((ares_channel)data->state.resolver);
+    ares_cancel((ares_channel)data->state.async.resolver);
 
   /* Operation complete, if the lookup was successful we now have the entry
      in the cache. */
   if(entry)
-    *entry = conn->async.dns;
+    *entry = data->state.async.dns;
 
   if(result)
     /* close the connection, since we can't return failure here without
        cleaning up this connection properly. */
-    connclose(conn, "c-ares resolve failed");
+    connclose(data->conn, "c-ares resolve failed");
 
   return result;
 }
@@ -525,7 +523,7 @@ static void query_completed_cb(void *arg,  /* (struct connectdata *) */
 #endif
                                struct hostent *hostent)
 {
-  struct connectdata *conn = (struct connectdata *)arg;
+  struct Curl_easy *data = (struct Curl_easy *)arg;
   struct thread_data *res;
 
 #ifdef HAVE_CARES_CALLBACK_TIMEOUTS
@@ -537,12 +535,12 @@ static void query_completed_cb(void *arg,  /* (struct connectdata *) */
        be valid so only defer it when we know the 'status' says its fine! */
     return;
 
-  res = conn->async.tdata;
+  res = data->state.async.tdata;
   if(res) {
     res->num_pending--;
 
     if(CURL_ASYNC_SUCCESS == status) {
-      struct Curl_addrinfo *ai = Curl_he2ai(hostent, conn->async.port);
+      struct Curl_addrinfo *ai = Curl_he2ai(hostent, data->state.async.port);
       if(ai) {
         compound_results(res, ai);
       }
@@ -607,8 +605,8 @@ static void query_completed_cb(void *arg,  /* (struct connectdata *) */
          c-ares retry cycle each request is.
       */
       res->happy_eyeballs_dns_time = Curl_now();
-      Curl_expire(
-        conn->data, HAPPY_EYEBALLS_DNS_TIMEOUT, EXPIRE_HAPPY_EYEBALLS_DNS);
+      Curl_expire(data, HAPPY_EYEBALLS_DNS_TIMEOUT,
+                  EXPIRE_HAPPY_EYEBALLS_DNS);
     }
   }
 }
@@ -621,19 +619,18 @@ static void query_completed_cb(void *arg,  /* (struct connectdata *) */
  * memory we need to free after use. That memory *MUST* be freed with
  * Curl_freeaddrinfo(), nothing else.
  */
-struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
                                                 const char *hostname,
                                                 int port,
                                                 int *waitp)
 {
   char *bufp;
-  struct Curl_easy *data = conn->data;
   int family = PF_INET;
 
   *waitp = 0; /* default to synchronous response */
 
 #ifdef ENABLE_IPV6
-  switch(conn->ip_version) {
+  switch(data->set.ipver) {
   default:
 #if ARES_VERSION >= 0x010601
     family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
@@ -653,19 +650,19 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
   bufp = strdup(hostname);
   if(bufp) {
     struct thread_data *res = NULL;
-    free(conn->async.hostname);
-    conn->async.hostname = bufp;
-    conn->async.port = port;
-    conn->async.done = FALSE;   /* not done */
-    conn->async.status = 0;     /* clear */
-    conn->async.dns = NULL;     /* clear */
+    free(data->state.async.hostname);
+    data->state.async.hostname = bufp;
+    data->state.async.port = port;
+    data->state.async.done = FALSE;   /* not done */
+    data->state.async.status = 0;     /* clear */
+    data->state.async.dns = NULL;     /* clear */
     res = calloc(sizeof(struct thread_data), 1);
     if(!res) {
-      free(conn->async.hostname);
-      conn->async.hostname = NULL;
+      free(data->state.async.hostname);
+      data->state.async.hostname = NULL;
       return NULL;
     }
-    conn->async.tdata = res;
+    data->state.async.tdata = res;
 
     /* initial status - failed */
     res->last_status = ARES_ENOTFOUND;
@@ -675,17 +672,17 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
         res->num_pending = 2;
 
         /* areschannel is already setup in the Curl_open() function */
-        ares_gethostbyname((ares_channel)data->state.resolver, hostname,
-                            PF_INET, query_completed_cb, conn);
-        ares_gethostbyname((ares_channel)data->state.resolver, hostname,
-                            PF_INET6, query_completed_cb, conn);
+        ares_gethostbyname((ares_channel)data->state.async.resolver, hostname,
+                            PF_INET, query_completed_cb, data);
+        ares_gethostbyname((ares_channel)data->state.async.resolver, hostname,
+                            PF_INET6, query_completed_cb, data);
       }
       else {
         res->num_pending = 1;
 
         /* areschannel is already setup in the Curl_open() function */
-        ares_gethostbyname((ares_channel)data->state.resolver, hostname,
-                            PF_INET, query_completed_cb, conn);
+        ares_gethostbyname((ares_channel)data->state.async.resolver, hostname,
+                            PF_INET, query_completed_cb, data);
       }
     }
     else
@@ -694,8 +691,9 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
       res->num_pending = 1;
 
       /* areschannel is already setup in the Curl_open() function */
-      ares_gethostbyname((ares_channel)data->state.resolver, hostname, family,
-                         query_completed_cb, conn);
+      ares_gethostbyname((ares_channel)data->state.async.resolver,
+                         hostname, family,
+                         query_completed_cb, data);
     }
 
     *waitp = 1; /* expect asynchronous response */
@@ -720,9 +718,10 @@ CURLcode Curl_set_dns_servers(struct Curl_easy *data,
 
 #if (ARES_VERSION >= 0x010704)
 #if (ARES_VERSION >= 0x010b00)
-  ares_result = ares_set_servers_ports_csv(data->state.resolver, servers);
+  ares_result = ares_set_servers_ports_csv(data->state.async.resolver,
+                                           servers);
 #else
-  ares_result = ares_set_servers_csv(data->state.resolver, servers);
+  ares_result = ares_set_servers_csv(data->state.async.resolver, servers);
 #endif
   switch(ares_result) {
   case ARES_SUCCESS:
@@ -752,7 +751,7 @@ CURLcode Curl_set_dns_interface(struct Curl_easy *data,
   if(!interf)
     interf = "";
 
-  ares_set_local_dev((ares_channel)data->state.resolver, interf);
+  ares_set_local_dev((ares_channel)data->state.async.resolver, interf);
 
   return CURLE_OK;
 #else /* c-ares version too old! */
@@ -777,7 +776,8 @@ CURLcode Curl_set_dns_local_ip4(struct Curl_easy *data,
     }
   }
 
-  ares_set_local_ip4((ares_channel)data->state.resolver, ntohl(a4.s_addr));
+  ares_set_local_ip4((ares_channel)data->state.async.resolver,
+                     ntohl(a4.s_addr));
 
   return CURLE_OK;
 #else /* c-ares version too old! */
@@ -803,7 +803,7 @@ CURLcode Curl_set_dns_local_ip6(struct Curl_easy *data,
     }
   }
 
-  ares_set_local_ip6((ares_channel)data->state.resolver, a6);
+  ares_set_local_ip6((ares_channel)data->state.async.resolver, a6);
 
   return CURLE_OK;
 #else /* c-ares version too old! */
diff --git a/lib/asyn-thread.c b/lib/asyn-thread.c
index 9caa1be099..e79aa9127b 100644
--- a/lib/asyn-thread.c
+++ b/lib/asyn-thread.c
@@ -145,13 +145,13 @@ static void destroy_async_data(struct Curl_async *);
 /*
  * Cancel all possibly still on-going resolves for this connection.
  */
-void Curl_resolver_cancel(struct connectdata *conn)
+void Curl_resolver_cancel(struct Curl_easy *data)
 {
-  destroy_async_data(&conn->async);
+  destroy_async_data(&data->state.async);
 }
 
 /* This function is used to init a threaded resolve */
-static bool init_resolve_thread(struct connectdata *conn,
+static bool init_resolve_thread(struct Curl_easy *data,
                                 const char *hostname, int port,
                                 const struct addrinfo *hints);
 
@@ -164,7 +164,7 @@ struct thread_sync_data {
   char *hostname;        /* hostname to resolve, Curl_async.hostname
                             duplicate */
 #ifdef USE_SOCKETPAIR
-  struct connectdata *conn;
+  struct Curl_easy *data;
   curl_socket_t sock_pair[2]; /* socket pair */
 #endif
   int sock_error;
@@ -182,9 +182,9 @@ struct thread_data {
   struct thread_sync_data tsd;
 };
 
-static struct thread_sync_data *conn_thread_sync_data(struct connectdata *conn)
+static struct thread_sync_data *conn_thread_sync_data(struct Curl_easy *data)
 {
-  return &(conn->async.tdata->tsd);
+  return &(data->state.async.tdata->tsd);
 }
 
 /* Destroy resolver thread synchronization data */
@@ -268,12 +268,12 @@ int init_thread_sync_data(struct thread_data *td,
   return 0;
 }
 
-static int getaddrinfo_complete(struct connectdata *conn)
+static int getaddrinfo_complete(struct Curl_easy *data)
 {
-  struct thread_sync_data *tsd = conn_thread_sync_data(conn);
+  struct thread_sync_data *tsd = conn_thread_sync_data(data);
   int rc;
 
-  rc = Curl_addrinfo_callback(conn, tsd->sock_error, tsd->res);
+  rc = Curl_addrinfo_callback(data, tsd->sock_error, tsd->res);
   /* The tsd->res structure has been copied to async.dns and perhaps the DNS
      cache.  Set our copy to NULL so destroy_thread_sync_data doesn't free it.
   */
@@ -384,7 +384,7 @@ static void destroy_async_data(struct Curl_async *async)
     int done;
 #ifdef USE_SOCKETPAIR
     curl_socket_t sock_rd = td->tsd.sock_pair[0];
-    struct connectdata *conn = td->tsd.conn;
+    struct Curl_easy *data = td->tsd.data;
 #endif
 
     /*
@@ -412,8 +412,7 @@ static void destroy_async_data(struct Curl_async *async)
      * ensure CURLMOPT_SOCKETFUNCTION fires CURL_POLL_REMOVE
      * before the FD is invalidated to avoid EBADF on EPOLL_CTL_DEL
      */
-    if(conn)
-      Curl_multi_closed(conn->data, sock_rd);
+    Curl_multi_closed(data, sock_rd);
     sclose(sock_rd);
 #endif
   }
@@ -429,32 +428,33 @@ static void destroy_async_data(struct Curl_async *async)
  *
  * Returns FALSE in case of failure, otherwise TRUE.
  */
-static bool init_resolve_thread(struct connectdata *conn,
+static bool init_resolve_thread(struct Curl_easy *data,
                                 const char *hostname, int port,
                                 const struct addrinfo *hints)
 {
   struct thread_data *td = calloc(1, sizeof(struct thread_data));
   int err = ENOMEM;
+  struct Curl_async *asp = &data->state.async;
 
-  conn->async.tdata = td;
+  data->state.async.tdata = td;
   if(!td)
     goto errno_exit;
 
-  conn->async.port = port;
-  conn->async.done = FALSE;
-  conn->async.status = 0;
-  conn->async.dns = NULL;
+  asp->port = port;
+  asp->done = FALSE;
+  asp->status = 0;
+  asp->dns = NULL;
   td->thread_hnd = curl_thread_t_null;
 
   if(!init_thread_sync_data(td, hostname, port, hints)) {
-    conn->async.tdata = NULL;
+    asp->tdata = NULL;
     free(td);
     goto errno_exit;
   }
 
-  free(conn->async.hostname);
-  conn->async.hostname = strdup(hostname);
-  if(!conn->async.hostname)
+  free(asp->hostname);
+  asp->hostname = strdup(hostname);
+  if(!asp->hostname)
     goto err_exit;
 
   /* The thread will set this to 1 when complete. */
@@ -476,7 +476,7 @@ static bool init_resolve_thread(struct connectdata *conn,
   return TRUE;
 
  err_exit:
-  destroy_async_data(&conn->async);
+  destroy_async_data(asp);
 
  errno_exit:
   errno = err;
@@ -488,12 +488,13 @@ static bool init_resolve_thread(struct connectdata *conn,
  * error
  */
 
-static CURLcode resolver_error(struct connectdata *conn)
+static CURLcode resolver_error(struct Curl_easy *data)
 {
   const char *host_or_proxy;
   CURLcode result;
 
 #ifndef CURL_DISABLE_PROXY
+  struct connectdata *conn = data->conn;
   if(conn->bits.httpproxy) {
     host_or_proxy = "proxy";
     result = CURLE_COULDNT_RESOLVE_PROXY;
@@ -505,8 +506,8 @@ static CURLcode resolver_error(struct connectdata *conn)
     result = CURLE_COULDNT_RESOLVE_HOST;
   }
 
-  failf(conn->data, "Could not resolve %s: %s", host_or_proxy,
-        conn->async.hostname);
+  failf(data, "Could not resolve %s: %s", host_or_proxy,
+        data->state.async.hostname);
 
   return result;
 }
@@ -514,37 +515,39 @@ static CURLcode resolver_error(struct connectdata *conn)
 /*
  * 'entry' may be NULL and then no data is returned
  */
-static CURLcode thread_wait_resolv(struct connectdata *conn,
+static CURLcode thread_wait_resolv(struct Curl_easy *data,
                                    struct Curl_dns_entry **entry,
                                    bool report)
 {
-  struct thread_data *td = conn->async.tdata;
+  struct thread_data *td;
   CURLcode result = CURLE_OK;
 
-  DEBUGASSERT(conn && td);
+  DEBUGASSERT(data);
+  td = data->state.async.tdata;
+  DEBUGASSERT(td);
   DEBUGASSERT(td->thread_hnd != curl_thread_t_null);
 
   /* wait for the thread to resolve the name */
   if(Curl_thread_join(&td->thread_hnd)) {
     if(entry)
-      result = getaddrinfo_complete(conn);
+      result = getaddrinfo_complete(data);
   }
   else
     DEBUGASSERT(0);
 
-  conn->async.done = TRUE;
+  data->state.async.done = TRUE;
 
   if(entry)
-    *entry = conn->async.dns;
+    *entry = data->state.async.dns;
 
-  if(!conn->async.dns && report)
+  if(!data->state.async.dns && report)
     /* a name was not resolved, report error */
-    result = resolver_error(conn);
+    result = resolver_error(data);
 
-  destroy_async_data(&conn->async);
+  destroy_async_data(&data->state.async);
 
-  if(!conn->async.dns && report)
-    connclose(conn, "asynch resolve failed");
+  if(!data->state.async.dns && report)
+    connclose(data->conn, "asynch resolve failed");
 
   return result;
 }
@@ -554,17 +557,17 @@ static CURLcode thread_wait_resolv(struct connectdata *conn,
  * Until we gain a way to signal the resolver threads to stop early, we must
  * simply wait for them and ignore their results.
  */
-void Curl_resolver_kill(struct connectdata *conn)
+void Curl_resolver_kill(struct Curl_easy *data)
 {
-  struct thread_data *td = conn->async.tdata;
+  struct thread_data *td = data->state.async.tdata;
 
   /* If we're still resolving, we must wait for the threads to fully clean up,
      unfortunately.  Otherwise, we can simply cancel to clean up any resolver
      data. */
   if(td && td->thread_hnd != curl_thread_t_null)
-    (void)thread_wait_resolv(conn, NULL, FALSE);
+    (void)thread_wait_resolv(data, NULL, FALSE);
   else
-    Curl_resolver_cancel(conn);
+    Curl_resolver_cancel(data);
 }
 
 /*
@@ -580,10 +583,10 @@ void Curl_resolver_kill(struct connectdata *conn)
  *
  * This is the version for resolves-in-a-thread.
  */
-CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
+CURLcode Curl_resolver_wait_resolv(struct Curl_easy *data,
                                    struct Curl_dns_entry **entry)
 {
-  return thread_wait_resolv(conn, entry, TRUE);
+  return thread_wait_resolv(data, entry, TRUE);
 }
 
 /*
@@ -591,11 +594,10 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
  * name resolve request has completed. It should also make sure to time-out if
  * the operation seems to take too long.
  */
-CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
+CURLcode Curl_resolver_is_resolved(struct Curl_easy *data,
                                    struct Curl_dns_entry **entry)
 {
-  struct Curl_easy *data = conn->data;
-  struct thread_data *td = conn->async.tdata;
+  struct thread_data *td = data->state.async.tdata;
   int done = 0;
 
   DEBUGASSERT(entry);
@@ -611,15 +613,15 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
   Curl_mutex_release(td->tsd.mtx);
 
   if(done) {
-    getaddrinfo_complete(conn);
+    getaddrinfo_complete(data);
 
-    if(!conn->async.dns) {
-      CURLcode result = resolver_error(conn);
-      destroy_async_data(&conn->async);
+    if(!data->state.async.dns) {
+      CURLcode result = resolver_error(data);
+      destroy_async_data(&data->state.async);
       return result;
     }
-    destroy_async_data(&conn->async);
-    *entry = conn->async.dns;
+    destroy_async_data(&data->state.async);
+    *entry = data->state.async.dns;
   }
   else {
     /* poll for name lookup done with exponential backoff up to 250ms */
@@ -640,22 +642,20 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
       td->poll_interval = 250;
 
     td->interval_end = elapsed + td->poll_interval;
-    Curl_expire(conn->data, td->poll_interval, EXPIRE_ASYNC_NAME);
+    Curl_expire(data, td->poll_interval, EXPIRE_ASYNC_NAME);
   }
 
   return CURLE_OK;
 }
 
-int Curl_resolver_getsock(struct connectdata *conn,
-                          curl_socket_t *socks)
+int Curl_resolver_getsock(struct Curl_easy *data, curl_socket_t *socks)
 {
   int ret_val = 0;
   timediff_t milli;
   timediff_t ms;
-  struct Curl_easy *data = conn->data;
-  struct resdata *reslv = (struct resdata *)data->state.resolver;
+  struct resdata *reslv = (struct resdata *)data->state.async.resolver;
 #ifdef USE_SOCKETPAIR
-  struct thread_data *td = conn->async.tdata;
+  struct thread_data *td = data->state.async.tdata;
 #else
   (void)socks;
 #endif
@@ -664,8 +664,7 @@ int Curl_resolver_getsock(struct connectdata *conn,
   if(td) {
     /* return read fd to client for polling the DNS resolution status */
     socks[0] = td->tsd.sock_pair[0];
-    DEBUGASSERT(td->tsd.conn == conn || !td->tsd.conn);
-    td->tsd.conn = conn;
+    td->tsd.data = data;
     ret_val = GETSOCK_READSOCK(0);
   }
   else {
@@ -692,12 +691,11 @@ int Curl_resolver_getsock(struct connectdata *conn,
 /*
  * Curl_getaddrinfo() - for platforms without getaddrinfo
  */
-struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
                                                 const char *hostname,
                                                 int port,
                                                 int *waitp)
 {
-  struct Curl_easy *data = conn->data;
   struct resdata *reslv = (struct resdata *)data->state.resolver;
 
   *waitp = 0; /* default to synchronous response */
@@ -705,7 +703,7 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
   reslv->start = Curl_now();
 
   /* fire up a new resolver thread! */
-  if(init_resolve_thread(conn, hostname, port, NULL)) {
+  if(init_resolve_thread(data, hostname, port, NULL)) {
     *waitp = 1; /* expect asynchronous response */
     return NULL;
   }
@@ -720,15 +718,14 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
 /*
  * Curl_resolver_getaddrinfo() - for getaddrinfo
  */
-struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
                                                 const char *hostname,
                                                 int port,
                                                 int *waitp)
 {
   struct addrinfo hints;
   int pf = PF_INET;
-  struct Curl_easy *data = conn->data;
-  struct resdata *reslv = (struct resdata *)data->state.resolver;
+  struct resdata *reslv = (struct resdata *)data->state.async.resolver;
 
   *waitp = 0; /* default to synchronous response */
 
@@ -736,7 +733,7 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
   /*
    * Check if a limited name resolve has been requested.
    */
-  switch(conn->ip_version) {
+  switch(data->set.ipver) {
   case CURL_IPRESOLVE_V4:
     pf = PF_INET;
     break;
@@ -755,12 +752,12 @@ struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
 
   memset(&hints, 0, sizeof(hints));
   hints.ai_family = pf;
-  hints.ai_socktype = (conn->transport == TRNSPRT_TCP)?
+  hints.ai_socktype = (data->conn->transport == TRNSPRT_TCP)?
     SOCK_STREAM : SOCK_DGRAM;
 
   reslv->start = Curl_now();
   /* fire up a new resolver thread! */
-  if(init_resolve_thread(conn, hostname, port, &hints)) {
+  if(init_resolve_thread(data, hostname, port, &hints)) {
     *waitp = 1; /* expect asynchronous response */
     return NULL;
   }
diff --git a/lib/asyn.h b/lib/asyn.h
index 73a9b7268f..3130395826 100644
--- a/lib/asyn.h
+++ b/lib/asyn.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -91,7 +91,7 @@ CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to,
  *
  * It is safe to call this when conn is in any state.
  */
-void Curl_resolver_cancel(struct connectdata *conn);
+void Curl_resolver_cancel(struct Curl_easy *data);
 
 /*
  * Curl_resolver_kill().
@@ -104,7 +104,7 @@ void Curl_resolver_cancel(struct connectdata *conn);
  *
  * It is safe to call this when conn is in any state.
  */
-void Curl_resolver_kill(struct connectdata *conn);
+void Curl_resolver_kill(struct Curl_easy *data);
 
 /* Curl_resolver_getsock()
  *
@@ -114,7 +114,7 @@ void Curl_resolver_kill(struct connectdata *conn);
  * return bitmask indicating what file descriptors (referring to array indexes
  * in the 'sock' array) to wait for, read/write.
  */
-int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *sock);
+int Curl_resolver_getsock(struct Curl_easy *data, curl_socket_t *sock);
 
 /*
  * Curl_resolver_is_resolved()
@@ -125,7 +125,7 @@ int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *sock);
  *
  * Returns normal CURLcode errors.
  */
-CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
+CURLcode Curl_resolver_is_resolved(struct Curl_easy *data,
                                    struct Curl_dns_entry **dns);
 
 /*
@@ -139,7 +139,7 @@ CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
  * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved,
  * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  */
-CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
+CURLcode Curl_resolver_wait_resolv(struct Curl_easy *data,
                                    struct Curl_dns_entry **dnsentry);
 
 /*
@@ -153,7 +153,7 @@ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
  * Each resolver backend must of course make sure to return data in the
  * correct format to comply with this.
  */
-struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
                                                 const char *hostname,
                                                 int port,
                                                 int *waitp);
diff --git a/lib/connect.c b/lib/connect.c
index 81ae006e86..052542449a 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -358,9 +358,9 @@ static CURLcode bindlocal(struct Curl_easy *data,
         conn->ip_version = CURL_IPRESOLVE_V6;
 #endif
 
-      rc = Curl_resolv(conn, dev, 0, FALSE, &h);
+      rc = Curl_resolv(data, dev, 0, FALSE, &h);
       if(rc == CURLRESOLV_PENDING)
-        (void)Curl_resolver_wait_resolv(conn, &h);
+        (void)Curl_resolver_wait_resolv(data, &h);
       conn->ip_version = ipver;
 
       if(h) {
diff --git a/lib/doh.c b/lib/doh.c
index 608f3d94c4..004244c8d2 100644
--- a/lib/doh.c
+++ b/lib/doh.c
@@ -379,21 +379,21 @@ static CURLcode dohprobe(struct Curl_easy *data,
  * 'Curl_addrinfo *' with the address information.
  */
 
-struct Curl_addrinfo *Curl_doh(struct connectdata *conn,
+struct Curl_addrinfo *Curl_doh(struct Curl_easy *data,
                                const char *hostname,
                                int port,
                                int *waitp)
 {
-  struct Curl_easy *data = conn->data;
   CURLcode result = CURLE_OK;
   int slot;
   struct dohdata *dohp;
+  struct connectdata *conn = data->conn;
   *waitp = TRUE; /* this never returns synchronously */
-  (void)conn;
   (void)hostname;
   (void)port;
 
   DEBUGASSERT(!data->req.doh);
+  DEBUGASSERT(conn);
 
   /* start clean, consider allocating this struct on demand */
   dohp = data->req.doh = calloc(sizeof(struct dohdata), 1);
@@ -911,11 +911,10 @@ UNITTEST void de_cleanup(struct dohentry *d)
   }
 }
 
-CURLcode Curl_doh_is_resolved(struct connectdata *conn,
+CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
                               struct Curl_dns_entry **dnsp)
 {
   CURLcode result;
-  struct Curl_easy *data = conn->data;
   struct dohdata *dohp = data->req.doh;
   *dnsp = NULL; /* defaults to no response */
   if(!dohp)
@@ -923,8 +922,8 @@ CURLcode Curl_doh_is_resolved(struct connectdata *conn,
 
   if(!dohp->probe[DOH_PROBE_SLOT_IPADDR_V4].easy &&
      !dohp->probe[DOH_PROBE_SLOT_IPADDR_V6].easy) {
-    failf(data, "Could not DOH-resolve: %s", conn->async.hostname);
-    return conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
+    failf(data, "Could not DOH-resolve: %s", data->state.async.hostname);
+    return data->conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
       CURLE_COULDNT_RESOLVE_HOST;
   }
   else if(!dohp->pending) {
@@ -984,7 +983,7 @@ CURLcode Curl_doh_is_resolved(struct connectdata *conn,
         Curl_freeaddrinfo(ai);
       }
       else {
-        conn->async.dns = dns;
+        data->state.async.dns = dns;
         *dnsp = dns;
         result = CURLE_OK;      /* address resolution OK */
       }
diff --git a/lib/doh.h b/lib/doh.h
index 0867584ced..b3584d1b27 100644
--- a/lib/doh.h
+++ b/lib/doh.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 2018 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 2018 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -32,12 +32,12 @@
  * and returns a 'Curl_addrinfo *' with the address information.
  */
 
-struct Curl_addrinfo *Curl_doh(struct connectdata *conn,
+struct Curl_addrinfo *Curl_doh(struct Curl_easy *data,
                                const char *hostname,
                                int port,
                                int *waitp);
 
-CURLcode Curl_doh_is_resolved(struct connectdata *conn,
+CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
                               struct Curl_dns_entry **dns);
 
 int Curl_doh_getsock(struct connectdata *conn, curl_socket_t *socks);
diff --git a/lib/easy.c b/lib/easy.c
index 3b72ce7a44..0fb255af49 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -908,8 +908,8 @@ struct Curl_easy *curl_easy_duphandle(struct Curl_easy *data)
 #endif
   /* Clone the resolver handle, if present, for the new handle */
   if(Curl_resolver_duphandle(outcurl,
-                             &outcurl->state.resolver,
-                             data->state.resolver))
+                             &outcurl->state.async.resolver,
+                             data->state.async.resolver))
     goto fail;
 
 #ifdef USE_ARES
diff --git a/lib/ftp.c b/lib/ftp.c
index 29566fb2f7..6a1cf4df97 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -1079,9 +1079,9 @@ static CURLcode ftp_state_use_port(struct Curl_easy *data,
   }
 
   /* resolv ip/host to ip */
-  rc = Curl_resolv(conn, host, 0, FALSE, &h);
+  rc = Curl_resolv(data, host, 0, FALSE, &h);
   if(rc == CURLRESOLV_PENDING)
-    (void)Curl_resolver_wait_resolv(conn, &h);
+    (void)Curl_resolver_wait_resolv(data, &h);
   if(h) {
     res = h->addr;
     /* when we return from this function, we can forget about this entry
@@ -1945,11 +1945,11 @@ static CURLcode ftp_state_pasv_resp(struct Curl_easy *data,
      */
     const char * const host_name = conn->bits.socksproxy ?
       conn->socks_proxy.host.name : conn->http_proxy.host.name;
-    rc = Curl_resolv(conn, host_name, (int)conn->port, FALSE, &addr);
+    rc = Curl_resolv(data, host_name, (int)conn->port, FALSE, &addr);
     if(rc == CURLRESOLV_PENDING)
       /* BLOCKING, ignores the return code but 'addr' will be NULL in
          case of failure */
-      (void)Curl_resolver_wait_resolv(conn, &addr);
+      (void)Curl_resolver_wait_resolv(data, &addr);
 
     connectport =
       (unsigned short)conn->port; /* we connect to the proxy's port */
@@ -1974,10 +1974,10 @@ static CURLcode ftp_state_pasv_resp(struct Curl_easy *data,
         return CURLE_OUT_OF_MEMORY;
     }
 
-    rc = Curl_resolv(conn, ftpc->newhost, ftpc->newport, FALSE, &addr);
+    rc = Curl_resolv(data, ftpc->newhost, ftpc->newport, FALSE, &addr);
     if(rc == CURLRESOLV_PENDING)
       /* BLOCKING */
-      (void)Curl_resolver_wait_resolv(conn, &addr);
+      (void)Curl_resolver_wait_resolv(data, &addr);
 
     connectport = ftpc->newport; /* we connect to the remote port */
 
diff --git a/lib/hostasyn.c b/lib/hostasyn.c
index 56a6fc2b72..b25de1d417 100644
--- a/lib/hostasyn.c
+++ b/lib/hostasyn.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -66,25 +66,23 @@
  *
  * The storage operation locks and unlocks the DNS cache.
  */
-CURLcode Curl_addrinfo_callback(struct connectdata *conn,
+CURLcode Curl_addrinfo_callback(struct Curl_easy *data,
                                 int status,
                                 struct Curl_addrinfo *ai)
 {
   struct Curl_dns_entry *dns = NULL;
   CURLcode result = CURLE_OK;
 
-  conn->async.status = status;
+  data->state.async.status = status;
 
   if(CURL_ASYNC_SUCCESS == status) {
     if(ai) {
-      struct Curl_easy *data = conn->data;
-
       if(data->share)
         Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
       dns = Curl_cache_addr(data, ai,
-                            conn->async.hostname,
-                            conn->async.port);
+                            data->state.async.hostname,
+                            data->state.async.port);
       if(data->share)
         Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 
@@ -99,12 +97,12 @@ CURLcode Curl_addrinfo_callback(struct connectdata *conn,
     }
   }
 
-  conn->async.dns = dns;
+  data->state.async.dns = dns;
 
  /* Set async.done TRUE last in this function since it may be used multi-
     threaded and once this is TRUE the other thread may read fields from the
     async struct */
-  conn->async.done = TRUE;
+  data->state.async.done = TRUE;
 
   /* IPv4: The input hostent struct will be freed by ares when we return from
      this function */
@@ -117,12 +115,12 @@ CURLcode Curl_addrinfo_callback(struct connectdata *conn,
  * name resolve layers (selected at build-time). They all take this same set
  * of arguments
  */
-struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data,
                                        const char *hostname,
                                        int port,
                                        int *waitp)
 {
-  return Curl_resolver_getaddrinfo(conn, hostname, port, waitp);
+  return Curl_resolver_getaddrinfo(data, hostname, port, waitp);
 }
 
 #endif /* CURLRES_ASYNCH */
diff --git a/lib/hostip.c b/lib/hostip.c
index a3f6090ab8..9ca9bdbe71 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -253,14 +253,12 @@ sigjmp_buf curl_jmpenv;
 #endif
 
 /* lookup address, returns entry if found and not stale */
-static struct Curl_dns_entry *
-fetch_addr(struct connectdata *conn,
-                const char *hostname,
-                int port)
+static struct Curl_dns_entry *fetch_addr(struct Curl_easy *data,
+                                         const char *hostname,
+                                         int port)
 {
   struct Curl_dns_entry *dns = NULL;
   size_t entry_len;
-  struct Curl_easy *data = conn->data;
   char entry_id[MAX_HOSTCACHE_LEN];
 
   /* Create an entry id, based upon the hostname and port */
@@ -321,7 +319,7 @@ Curl_fetch_addr(struct connectdata *conn,
   if(data->share)
     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
-  dns = fetch_addr(conn, hostname, port);
+  dns = fetch_addr(data, hostname, port);
 
   if(dns)
     dns->inuse++; /* we use it! */
@@ -480,16 +478,16 @@ Curl_cache_addr(struct Curl_easy *data,
  * CURLRESOLV_PENDING  (1) = waiting for response, no pointer
  */
 
-enum resolve_t Curl_resolv(struct connectdata *conn,
+enum resolve_t Curl_resolv(struct Curl_easy *data,
                            const char *hostname,
                            int port,
                            bool allowDOH,
                            struct Curl_dns_entry **entry)
 {
   struct Curl_dns_entry *dns = NULL;
-  struct Curl_easy *data = conn->data;
   CURLcode result;
   enum resolve_t rc = CURLRESOLV_ERROR; /* default to failure */
+  struct connectdata *conn = data->conn;
 
   *entry = NULL;
   conn->bits.doh = FALSE; /* default is not */
@@ -497,7 +495,7 @@ enum resolve_t Curl_resolv(struct connectdata *conn,
   if(data->share)
     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
-  dns = fetch_addr(conn, hostname, port);
+  dns = fetch_addr(data, hostname, port);
 
   if(dns) {
     infof(data, "Hostname %s was found in DNS cache\n", hostname);
@@ -523,7 +521,7 @@ enum resolve_t Curl_resolv(struct connectdata *conn,
     if(data->set.resolver_start) {
       int st;
       Curl_set_in_callback(data, true);
-      st = data->set.resolver_start(data->state.resolver, NULL,
+      st = data->set.resolver_start(data->state.async.resolver, NULL,
                                     data->set.resolver_start_client);
       Curl_set_in_callback(data, false);
       if(st)
@@ -569,13 +567,13 @@ enum resolve_t Curl_resolv(struct connectdata *conn,
         return CURLRESOLV_ERROR;
 
       if(allowDOH && data->set.doh && !ipnum) {
-        addr = Curl_doh(conn, hostname, port, &respwait);
+        addr = Curl_doh(data, hostname, port, &respwait);
       }
       else {
         /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a
            non-zero value indicating that we need to wait for the response to
            the resolve call */
-        addr = Curl_getaddrinfo(conn,
+        addr = Curl_getaddrinfo(data,
 #ifdef DEBUGBUILD
                                 (data->set.str[STRING_DEVICE]
                                  && !strcmp(data->set.str[STRING_DEVICE],
@@ -589,7 +587,7 @@ enum resolve_t Curl_resolv(struct connectdata *conn,
         /* the response to our resolve call will come asynchronously at
            a later time, good or bad */
         /* First, check that we haven't received the info by now */
-        result = Curl_resolv_check(conn, &dns);
+        result = Curl_resolv_check(data, &dns);
         if(result) /* error detected */
           return CURLRESOLV_ERROR;
         if(dns)
@@ -658,7 +656,7 @@ RETSIGTYPE alarmfunc(int sig)
  * CURLRESOLV_PENDING  (1) = waiting for response, no pointer
  */
 
-enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
+enum resolve_t Curl_resolv_timeout(struct Curl_easy *data,
                                    const char *hostname,
                                    int port,
                                    struct Curl_dns_entry **entry,
@@ -676,7 +674,6 @@ enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
 #endif /* HAVE_SIGACTION */
   volatile long timeout;
   volatile unsigned int prev_alarm = 0;
-  struct Curl_easy *data = conn->data;
 #endif /* USE_ALARM_TIMEOUT */
   enum resolve_t rc;
 
@@ -695,7 +692,7 @@ enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
 
   if(!timeout)
     /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */
-    return Curl_resolv(conn, hostname, port, TRUE, entry);
+    return Curl_resolv(data, hostname, port, TRUE, entry);
 
   if(timeout < 1000) {
     /* The alarm() function only provides integer second resolution, so if
@@ -748,7 +745,7 @@ enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
 #else
 #ifndef CURLRES_ASYNCH
   if(timeoutms)
-    infof(conn->data, "timeout on name lookup is not supported\n");
+    infof(data, "timeout on name lookup is not supported\n");
 #else
   (void)timeoutms; /* timeoutms not used with an async resolver */
 #endif
@@ -757,7 +754,7 @@ enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
   /* Perform the actual name resolution. This might be interrupted by an
    * alarm if it takes too long.
    */
-  rc = Curl_resolv(conn, hostname, port, TRUE, entry);
+  rc = Curl_resolv(data, hostname, port, TRUE, entry);
 
 #ifdef USE_ALARM_TIMEOUT
 clean_up:
@@ -784,7 +781,7 @@ clean_up:
   if(prev_alarm) {
     /* there was an alarm() set before us, now put it back */
     timediff_t elapsed_secs = Curl_timediff(Curl_now(),
-                                            conn->created) / 1000;
+                                            data->conn->created) / 1000;
 
     /* the alarm period is counted in even number of seconds */
     unsigned long alarm_set = (unsigned long)(prev_alarm - elapsed_secs);
@@ -1068,29 +1065,29 @@ CURLcode Curl_loadhostpairs(struct Curl_easy *data)
   return CURLE_OK;
 }
 
-CURLcode Curl_resolv_check(struct connectdata *conn,
+CURLcode Curl_resolv_check(struct Curl_easy *data,
                            struct Curl_dns_entry **dns)
 {
 #if defined(CURL_DISABLE_DOH) && !defined(CURLRES_ASYNCH)
   (void)dns;
 #endif
 
-  if(conn->bits.doh)
-    return Curl_doh_is_resolved(conn, dns);
-  return Curl_resolver_is_resolved(conn, dns);
+  if(data->conn->bits.doh)
+    return Curl_doh_is_resolved(data, dns);
+  return Curl_resolver_is_resolved(data, dns);
 }
 
-int Curl_resolv_getsock(struct connectdata *conn,
+int Curl_resolv_getsock(struct Curl_easy *data,
                         curl_socket_t *socks)
 {
 #ifdef CURLRES_ASYNCH
-  if(conn->bits.doh)
+  if(data->conn->bits.doh)
     /* nothing to wait for during DOH resolve, those handles have their own
        sockets */
     return GETSOCK_BLANK;
-  return Curl_resolver_getsock(conn, socks);
+  return Curl_resolver_getsock(data, socks);
 #else
-  (void)conn;
+  (void)data;
   (void)socks;
   return GETSOCK_BLANK;
 #endif
@@ -1101,21 +1098,19 @@ int Curl_resolv_getsock(struct connectdata *conn,
 
    Note: this function disconnects and frees the conn data in case of
    resolve failure */
-CURLcode Curl_once_resolved(struct connectdata *conn,
-                            bool *protocol_done)
+CURLcode Curl_once_resolved(struct Curl_easy *data, bool *protocol_done)
 {
   CURLcode result;
+  struct connectdata *conn = data->conn;
 
-  if(conn->async.dns) {
-    conn->dns_entry = conn->async.dns;
-    conn->async.dns = NULL;
+  if(data->state.async.dns) {
+    conn->dns_entry = data->state.async.dns;
+    data->state.async.dns = NULL;
   }
 
   result = Curl_setup_conn(conn, protocol_done);
 
   if(result) {
-    struct Curl_easy *data = conn->data;
-    DEBUGASSERT(data);
     Curl_detach_connnection(data);
     Curl_conncache_remove_conn(data, conn, TRUE);
     Curl_disconnect(data, conn, TRUE);
diff --git a/lib/hostip.h b/lib/hostip.h
index 60e0b7795b..6deeb9f9cb 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -85,12 +85,12 @@ enum resolve_t {
   CURLRESOLV_RESOLVED =  0,
   CURLRESOLV_PENDING  =  1
 };
-enum resolve_t Curl_resolv(struct connectdata *conn,
+enum resolve_t Curl_resolv(struct Curl_easy *data,
                            const char *hostname,
                            int port,
                            bool allowDOH,
                            struct Curl_dns_entry **dnsentry);
-enum resolve_t Curl_resolv_timeout(struct connectdata *conn,
+enum resolve_t Curl_resolv_timeout(struct Curl_easy *data,
                                    const char *hostname, int port,
                                    struct Curl_dns_entry **dnsentry,
                                    timediff_t timeoutms);
@@ -117,7 +117,7 @@ bool Curl_ipvalid(struct Curl_easy *data, struct connectdata *conn);
  * name resolve layers (selected at build-time). They all take this same set
  * of arguments
  */
-struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data,
                                        const char *hostname,
                                        int port,
                                        int *waitp);
@@ -148,7 +148,7 @@ int curl_dogetnameinfo(GETNAMEINFO_QUAL_ARG1 GETNAMEINFO_TYPE_ARG1 sa,
 /* IPv4 threadsafe resolve function used for synch and asynch builds */
 struct Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, int port);
 
-CURLcode Curl_once_resolved(struct connectdata *conn, bool *protocol_connect);
+CURLcode Curl_once_resolved(struct Curl_easy *data, bool *protocol_connect);
 
 /*
  * Curl_addrinfo_callback() is used when we build with any asynch specialty.
@@ -156,7 +156,7 @@ CURLcode Curl_once_resolved(struct connectdata *conn, bool *protocol_connect);
  * status is CURL_ASYNC_SUCCESS. Twiddles fields in conn to indicate async
  * request completed whether successful or failed.
  */
-CURLcode Curl_addrinfo_callback(struct connectdata *conn,
+CURLcode Curl_addrinfo_callback(struct Curl_easy *data,
                                 int status,
                                 struct Curl_addrinfo *ai);
 
@@ -240,10 +240,9 @@ void Curl_hostcache_clean(struct Curl_easy *data, struct Curl_hash *hash);
  * Populate the cache with specified entries from CURLOPT_RESOLVE.
  */
 CURLcode Curl_loadhostpairs(struct Curl_easy *data);
-
-CURLcode Curl_resolv_check(struct connectdata *conn,
+CURLcode Curl_resolv_check(struct Curl_easy *data,
                            struct Curl_dns_entry **dns);
-int Curl_resolv_getsock(struct connectdata *conn,
+int Curl_resolv_getsock(struct Curl_easy *data,
                         curl_socket_t *socks);
 
 #endif /* HEADER_CURL_HOSTIP_H */
diff --git a/lib/hostip4.c b/lib/hostip4.c
index f1acb90939..d0754af223 100644
--- a/lib/hostip4.c
+++ b/lib/hostip4.c
@@ -89,7 +89,7 @@ bool Curl_ipvalid(struct Curl_easy *data, struct connectdata *conn)
  * flavours have thread-safe versions of the plain gethostbyname() etc.
  *
  */
-struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data,
                                        const char *hostname,
                                        int port,
                                        int *waitp)
@@ -97,14 +97,14 @@ struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
   struct Curl_addrinfo *ai = NULL;
 
 #ifdef CURL_DISABLE_VERBOSE_STRINGS
-  (void)conn;
+  (void)data;
 #endif
 
   *waitp = 0; /* synchronous response only */
 
   ai = Curl_ipv4_resolve_r(hostname, port);
   if(!ai)
-    infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname);
+    infof(data, "Curl_ipv4_resolve_r failed for %s\n", hostname);
 
   return ai;
 }
diff --git a/lib/hostip6.c b/lib/hostip6.c
index f9dd627ee4..53b3c67223 100644
--- a/lib/hostip6.c
+++ b/lib/hostip6.c
@@ -127,7 +127,7 @@ static void dump_addrinfo(struct connectdata *conn,
  * memory we need to free after use. That memory *MUST* be freed with
  * Curl_freeaddrinfo(), nothing else.
  */
-struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
+struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data,
                                        const char *hostname,
                                        int port,
                                        int *waitp)
@@ -141,14 +141,11 @@ struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
   char addrbuf[128];
 #endif
   int pf;
-#if !defined(CURL_DISABLE_VERBOSE_STRINGS)
-  struct Curl_easy *data = conn->data;
-#endif
 
   *waitp = 0; /* synchronous response only */
 
   /* Check if a limited name resolve has been requested */
-  switch(conn->ip_version) {
+  switch(data->set.ipver) {
   case CURL_IPRESOLVE_V4:
     pf = PF_INET;
     break;
@@ -166,7 +163,7 @@ struct Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
 
   memset(&hints, 0, sizeof(hints));
   hints.ai_family = pf;
-  hints.ai_socktype = (conn->transport == TRNSPRT_TCP) ?
+  hints.ai_socktype = (data->conn->transport == TRNSPRT_TCP) ?
     SOCK_STREAM : SOCK_DGRAM;
 
 #ifndef USE_RESOLVE_ON_IPS
diff --git a/lib/multi.c b/lib/multi.c
index 34c916e336..0f9d79dc2d 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -565,7 +565,7 @@ static CURLcode multi_done(struct Curl_easy *data,
   conn->data = data; /* ensure the connection uses this transfer now */
 
   /* Stop the resolver and free its own resources (but not dns_entry yet). */
-  Curl_resolver_kill(conn);
+  Curl_resolver_kill(data);
 
   /* Cleanup possible redirect junk */
   Curl_safefree(data->req.newurl);
@@ -995,7 +995,7 @@ static int multi_getsock(struct Curl_easy *data,
     return 0;
 
   case CURLM_STATE_WAITRESOLVE:
-    return Curl_resolv_getsock(conn, socks);
+    return Curl_resolv_getsock(data, socks);
 
   case CURLM_STATE_PROTOCONNECT:
   case CURLM_STATE_SENDPROTOCONNECT:
@@ -1733,15 +1733,15 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
 
       if(dns) {
 #ifdef CURLRES_ASYNCH
-        conn->async.dns = dns;
-        conn->async.done = TRUE;
+        data->state.async.dns = dns;
+        data->state.async.done = TRUE;
 #endif
         result = CURLE_OK;
         infof(data, "Hostname '%s' was found in DNS cache\n", hostname);
       }
 
       if(!dns)
-        result = Curl_resolv_check(data->conn, &dns);
+        result = Curl_resolv_check(data, &dns);
 
       /* Update sockets here, because the socket(s) may have been
          closed and the application thus needs to be told, even if it
@@ -1754,7 +1754,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
       if(dns) {
         /* Perform the next step in the connection phase, and then move on
            to the WAITCONNECT state */
-        result = Curl_once_resolved(data->conn, &protocol_connected);
+        result = Curl_once_resolved(data, &protocol_connected);
 
         if(result)
           /* if Curl_once_resolved() returns failure, the connection struct
diff --git a/lib/socks.c b/lib/socks.c
index 9252e2c174..165c5496f5 100644
--- a/lib/socks.c
+++ b/lib/socks.c
@@ -238,7 +238,7 @@ CURLproxycode Curl_SOCKS4(const char *proxy_user,
     /* DNS resolve only for SOCKS4, not SOCKS4a */
     if(!protocol4a) {
       enum resolve_t rc =
-        Curl_resolv(conn, hostname, remote_port, FALSE, &dns);
+        Curl_resolv(data, hostname, remote_port, FALSE, &dns);
 
       if(rc == CURLRESOLV_ERROR)
         return CURLPX_RESOLVE_HOST;
@@ -261,14 +261,14 @@ CURLproxycode Curl_SOCKS4(const char *proxy_user,
 
     if(dns) {
 #ifdef CURLRES_ASYNCH
-      conn->async.dns = dns;
-      conn->async.done = TRUE;
+      data->state.async.dns = dns;
+      data->state.async.done = TRUE;
 #endif
       infof(data, "Hostname '%s' was found\n", hostname);
       sxstate(data, CONNECT_RESOLVED);
     }
     else {
-      result = Curl_resolv_check(data->conn, &dns);
+      result = Curl_resolv_check(data, &dns);
       if(!dns) {
         if(result)
           return CURLPX_RESOLVE_HOST;
@@ -754,7 +754,7 @@ CURLproxycode Curl_SOCKS5(const char *proxy_user,
   CONNECT_REQ_INIT:
   case CONNECT_REQ_INIT:
     if(socks5_resolve_local) {
-      enum resolve_t rc = Curl_resolv(conn, hostname, remote_port,
+      enum resolve_t rc = Curl_resolv(data, hostname, remote_port,
                                       FALSE, &dns);
 
       if(rc == CURLRESOLV_ERROR)
@@ -775,14 +775,14 @@ CURLproxycode Curl_SOCKS5(const char *proxy_user,
 
     if(dns) {
 #ifdef CURLRES_ASYNCH
-      conn->async.dns = dns;
-      conn->async.done = TRUE;
+      data->state.async.dns = dns;
+      data->state.async.done = TRUE;
 #endif
       infof(data, "SOCKS5: hostname '%s' found\n", hostname);
     }
 
     if(!dns) {
-      result = Curl_resolv_check(data->conn, &dns);
+      result = Curl_resolv_check(data, &dns);
       if(!dns) {
         if(result)
           return CURLPX_RESOLVE_HOST;
diff --git a/lib/url.c b/lib/url.c
index fe6c9a1f27..38f51e8a34 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -427,7 +427,7 @@ CURLcode Curl_close(struct Curl_easy **datap)
   Curl_safefree(data->info.wouldredirect);
 
   /* this destroys the channel and we cannot use it anymore after this */
-  Curl_resolver_cleanup(data->state.resolver);
+  Curl_resolver_cleanup(data->state.async.resolver);
 
   Curl_http2_cleanup_dependencies(data);
   Curl_convert_close(data);
@@ -643,7 +643,7 @@ CURLcode Curl_open(struct Curl_easy **curl)
 
   data->magic = CURLEASY_MAGIC_NUMBER;
 
-  result = Curl_resolver_init(data, &data->state.resolver);
+  result = Curl_resolver_init(data, &data->state.async.resolver);
   if(result) {
     DEBUGF(fprintf(stderr, "Error: resolver_init failed\n"));
     free(data);
@@ -664,7 +664,7 @@ CURLcode Curl_open(struct Curl_easy **curl)
   }
 
   if(result) {
-    Curl_resolver_cleanup(data->state.resolver);
+    Curl_resolver_cleanup(data->state.async.resolver);
     Curl_dyn_free(&data->state.headerb);
     Curl_freeset(data);
     free(data);
@@ -722,7 +722,7 @@ static void conn_shutdown(struct Curl_easy *data, struct connectdata *conn)
   infof(data, "Closing connection %ld\n", conn->connection_id);
 
   /* possible left-overs from the async name resolvers */
-  Curl_resolver_cancel(conn);
+  Curl_resolver_cancel(data);
 
   /* close the SSL stuff before we close any sockets since they will/may
      write to the sockets */
@@ -3307,7 +3307,7 @@ static CURLcode resolve_server(struct Curl_easy *data,
       conn->hostname_resolve = strdup(connhost->name);
       if(!conn->hostname_resolve)
         return CURLE_OUT_OF_MEMORY;
-      rc = Curl_resolv_timeout(conn, conn->hostname_resolve, (int)conn->port,
+      rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
                                &hostaddr, timeout_ms);
       if(rc == CURLRESOLV_PENDING)
         *async = TRUE;
@@ -3332,7 +3332,7 @@ static CURLcode resolve_server(struct Curl_easy *data,
       conn->hostname_resolve = strdup(host->name);
       if(!conn->hostname_resolve)
         return CURLE_OUT_OF_MEMORY;
-      rc = Curl_resolv_timeout(conn, conn->hostname_resolve, (int)conn->port,
+      rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
                                &hostaddr, timeout_ms);
 
       if(rc == CURLRESOLV_PENDING)
diff --git a/lib/urldata.h b/lib/urldata.h
index 5f3b7e7ec6..95ef175a12 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -539,15 +539,21 @@ struct hostname {
 #define KEEP_RECVBITS (KEEP_RECV | KEEP_RECV_HOLD | KEEP_RECV_PAUSE)
 #define KEEP_SENDBITS (KEEP_SEND | KEEP_SEND_HOLD | KEEP_SEND_PAUSE)
 
+#if defined(CURLRES_ASYNCH) || !defined(CURL_DISABLE_DOH)
+#define USE_CURL_ASYNC
 struct Curl_async {
   char *hostname;
-  int port;
-  int status; /* if done is TRUE, this is the status from the callback */
   struct Curl_dns_entry *dns;
   struct thread_data *tdata;
+  void *resolver; /* resolver state, if it is used in the URL state -
+                     ares_channel f.e. */
+  int port;
+  int status; /* if done is TRUE, this is the status from the callback */
   BIT(done);  /* set TRUE when the lookup is complete */
 };
 
+#endif
+
 #define FIRSTSOCKET     0
 #define SECONDARYSOCKET 1
 
@@ -1093,9 +1099,6 @@ struct connectdata {
   struct negotiatedata proxyneg; /* state data for proxy Negotiate auth */
 #endif
 
-  /* data used for the asynch name resolve callback */
-  struct Curl_async async;
-
   /* for chunked-encoded trailer */
   struct dynbuf trailer;
 
@@ -1330,7 +1333,6 @@ struct urlpieces {
 struct UrlState {
   /* Points to the connection cache */
   struct conncache *conn_cache;
-
   int retrycount; /* number of retries on a new connection */
 
   /* buffers to store authentication data in, as parsed from input options */
@@ -1365,8 +1367,9 @@ struct UrlState {
 
   struct auth authhost;  /* auth details for host */
   struct auth authproxy; /* auth details for proxy */
-  void *resolver; /* resolver state, if it is used in the URL state -
-                     ares_channel f.e. */
+#ifdef USE_CURL_ASYNC
+  struct Curl_async async;  /* asynchronous name resolver data */
+#endif
 
 #if defined(USE_OPENSSL)
   /* void instead of ENGINE to avoid bleeding OpenSSL into this header */
diff --git a/tests/data/test1082 b/tests/data/test1082
index 0df70afaed..6791a6b10b 100644
--- a/tests/data/test1082
+++ b/tests/data/test1082
@@ -32,7 +32,7 @@ http
 HTTP GET with localhost --interface
  </name>
  <command>
-http://%HOSTIP:%HTTPPORT/1082 --interface localhost
+http://%HOSTIP:%HTTPPORT/1082 -4 --interface localhost
 </command>
 <precheck>
 perl -e "print 'Test requires default test client host address' if ( '%CLIENTIP' ne '127.0.0.1' );"