Update networking layer w/ CURL and emscripten impl

2025-11-08 01:50:36 +11:00
parent a17925904d
commit f6874dc55a
4105 changed files with 694617 additions and 179 deletions
@@ -0,0 +1,752 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 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
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#ifndef CURL_DISABLE_HTTP
+
+#include "urldata.h"
+#include <curl/curl.h>
+#include "curl_trc.h"
+#include "cfilters.h"
+#include "connect.h"
+#include "hostip.h"
+#include "multiif.h"
+#include "cf-https-connect.h"
+#include "http2.h"
+#include "select.h"
+#include "vquic/vquic.h"
+
+/* The last 2 #include files should be in this order */
+#include "curl_memory.h"
+#include "memdebug.h"
+
+typedef enum {
+  CF_HC_INIT,
+  CF_HC_CONNECT,
+  CF_HC_SUCCESS,
+  CF_HC_FAILURE
+} cf_hc_state;
+
+struct cf_hc_baller {
+  const char *name;
+  struct Curl_cfilter *cf;
+  CURLcode result;
+  struct curltime started;
+  int reply_ms;
+  unsigned char transport;
+  enum alpnid alpn_id;
+  BIT(shutdown);
+};
+
+static void cf_hc_baller_reset(struct cf_hc_baller *b,
+                               struct Curl_easy *data)
+{
+  if(b->cf) {
+    Curl_conn_cf_close(b->cf, data);
+    Curl_conn_cf_discard_chain(&b->cf, data);
+    b->cf = NULL;
+  }
+  b->result = CURLE_OK;
+  b->reply_ms = -1;
+}
+
+static bool cf_hc_baller_is_active(struct cf_hc_baller *b)
+{
+  return b->cf && !b->result;
+}
+
+static bool cf_hc_baller_has_started(struct cf_hc_baller *b)
+{
+  return !!b->cf;
+}
+
+static int cf_hc_baller_reply_ms(struct cf_hc_baller *b,
+                                 struct Curl_easy *data)
+{
+  if(b->cf && (b->reply_ms < 0))
+    b->cf->cft->query(b->cf, data, CF_QUERY_CONNECT_REPLY_MS,
+                      &b->reply_ms, NULL);
+  return b->reply_ms;
+}
+
+static bool cf_hc_baller_data_pending(struct cf_hc_baller *b,
+                                      const struct Curl_easy *data)
+{
+  return b->cf && !b->result && b->cf->cft->has_data_pending(b->cf, data);
+}
+
+static bool cf_hc_baller_needs_flush(struct cf_hc_baller *b,
+                                     struct Curl_easy *data)
+{
+  return b->cf && !b->result && Curl_conn_cf_needs_flush(b->cf, data);
+}
+
+static CURLcode cf_hc_baller_cntrl(struct cf_hc_baller *b,
+                                   struct Curl_easy *data,
+                                   int event, int arg1, void *arg2)
+{
+  if(b->cf && !b->result)
+    return Curl_conn_cf_cntrl(b->cf, data, FALSE, event, arg1, arg2);
+  return CURLE_OK;
+}
+
+struct cf_hc_ctx {
+  cf_hc_state state;
+  struct curltime started;  /* when connect started */
+  CURLcode result;          /* overall result */
+  struct cf_hc_baller ballers[2];
+  size_t baller_count;
+  timediff_t soft_eyeballs_timeout_ms;
+  timediff_t hard_eyeballs_timeout_ms;
+};
+
+static void cf_hc_baller_assign(struct cf_hc_baller *b,
+                                enum alpnid alpn_id,
+                                unsigned char def_transport)
+{
+  b->alpn_id = alpn_id;
+  b->transport = def_transport;
+  switch(b->alpn_id) {
+  case ALPN_h3:
+    b->name = "h3";
+    b->transport = TRNSPRT_QUIC;
+    break;
+  case ALPN_h2:
+    b->name = "h2";
+    break;
+  case ALPN_h1:
+    b->name = "h1";
+    break;
+  default:
+    b->result = CURLE_FAILED_INIT;
+    break;
+  }
+}
+
+static void cf_hc_baller_init(struct cf_hc_baller *b,
+                              struct Curl_cfilter *cf,
+                              struct Curl_easy *data,
+                              int transport)
+{
+  struct Curl_cfilter *save = cf->next;
+
+  cf->next = NULL;
+  b->started = curlx_now();
+  switch(b->alpn_id) {
+  case ALPN_h3:
+    transport = TRNSPRT_QUIC;
+    break;
+  default:
+    break;
+  }
+
+  if(!b->result)
+    b->result = Curl_cf_setup_insert_after(cf, data, transport,
+                                           CURL_CF_SSL_ENABLE);
+  b->cf = cf->next;
+  cf->next = save;
+}
+
+static CURLcode cf_hc_baller_connect(struct cf_hc_baller *b,
+                                     struct Curl_cfilter *cf,
+                                     struct Curl_easy *data,
+                                     bool *done)
+{
+  struct Curl_cfilter *save = cf->next;
+
+  cf->next = b->cf;
+  b->result = Curl_conn_cf_connect(cf->next, data, done);
+  b->cf = cf->next; /* it might mutate */
+  cf->next = save;
+  return b->result;
+}
+
+static void cf_hc_reset(struct Curl_cfilter *cf, struct Curl_easy *data)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  size_t i;
+
+  if(ctx) {
+    for(i = 0; i < ctx->baller_count; ++i)
+      cf_hc_baller_reset(&ctx->ballers[i], data);
+    ctx->state = CF_HC_INIT;
+    ctx->result = CURLE_OK;
+    ctx->hard_eyeballs_timeout_ms = data->set.happy_eyeballs_timeout;
+    ctx->soft_eyeballs_timeout_ms = data->set.happy_eyeballs_timeout / 4;
+  }
+}
+
+static CURLcode baller_connected(struct Curl_cfilter *cf,
+                                 struct Curl_easy *data,
+                                 struct cf_hc_baller *winner)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  CURLcode result = CURLE_OK;
+  int reply_ms;
+  size_t i;
+
+  DEBUGASSERT(winner->cf);
+  for(i = 0; i < ctx->baller_count; ++i)
+    if(winner != &ctx->ballers[i])
+      cf_hc_baller_reset(&ctx->ballers[i], data);
+
+  reply_ms = cf_hc_baller_reply_ms(winner, data);
+  if(reply_ms >= 0)
+    CURL_TRC_CF(data, cf, "connect+handshake %s: %dms, 1st data: %dms",
+                winner->name, (int)curlx_timediff(curlx_now(),
+                                                  winner->started), reply_ms);
+  else
+    CURL_TRC_CF(data, cf, "deferred handshake %s: %dms",
+                winner->name, (int)curlx_timediff(curlx_now(),
+                                                  winner->started));
+
+  /* install the winning filter below this one. */
+  cf->next = winner->cf;
+  winner->cf = NULL;
+
+#ifdef USE_NGHTTP2
+  {
+    /* Using nghttp2, we add the filter "below" us, so when the conn
+     * closes, we tear it down for a fresh reconnect */
+    const char *alpn = Curl_conn_cf_get_alpn_negotiated(cf->next, data);
+    if(alpn && !strcmp("h2", alpn)) {
+      result = Curl_http2_switch_at(cf, data);
+      if(result) {
+        ctx->state = CF_HC_FAILURE;
+        ctx->result = result;
+        return result;
+      }
+    }
+  }
+#endif
+
+  ctx->state = CF_HC_SUCCESS;
+  cf->connected = TRUE;
+  return result;
+}
+
+
+static bool time_to_start_next(struct Curl_cfilter *cf,
+                               struct Curl_easy *data,
+                               size_t idx, struct curltime now)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  timediff_t elapsed_ms;
+  size_t i;
+
+  if(idx >= ctx->baller_count)
+    return FALSE;
+  if(cf_hc_baller_has_started(&ctx->ballers[idx]))
+    return FALSE;
+  for(i = 0; i < idx; i++) {
+    if(!ctx->ballers[i].result)
+      break;
+  }
+  if(i == idx) {
+    CURL_TRC_CF(data, cf, "all previous attempts failed, starting %s",
+                ctx->ballers[idx].name);
+    return TRUE;
+  }
+  elapsed_ms = curlx_timediff(now, ctx->started);
+  if(elapsed_ms >= ctx->hard_eyeballs_timeout_ms) {
+    CURL_TRC_CF(data, cf, "hard timeout of %" FMT_TIMEDIFF_T "ms reached, "
+                "starting %s",
+                ctx->hard_eyeballs_timeout_ms, ctx->ballers[idx].name);
+    return TRUE;
+  }
+
+  if((idx > 0) && (elapsed_ms >= ctx->soft_eyeballs_timeout_ms)) {
+    if(cf_hc_baller_reply_ms(&ctx->ballers[idx - 1], data) < 0) {
+      CURL_TRC_CF(data, cf, "soft timeout of %" FMT_TIMEDIFF_T "ms reached, "
+                  "%s has not seen any data, starting %s",
+                  ctx->soft_eyeballs_timeout_ms,
+                  ctx->ballers[idx - 1].name, ctx->ballers[idx].name);
+      return TRUE;
+    }
+    /* set the effective hard timeout again */
+    Curl_expire(data, ctx->hard_eyeballs_timeout_ms - elapsed_ms,
+                EXPIRE_ALPN_EYEBALLS);
+  }
+  return FALSE;
+}
+
+static CURLcode cf_hc_connect(struct Curl_cfilter *cf,
+                              struct Curl_easy *data,
+                              bool *done)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  struct curltime now;
+  CURLcode result = CURLE_OK;
+  size_t i, failed_ballers;
+
+  if(cf->connected) {
+    *done = TRUE;
+    return CURLE_OK;
+  }
+
+  *done = FALSE;
+  now = curlx_now();
+  switch(ctx->state) {
+  case CF_HC_INIT:
+    DEBUGASSERT(!cf->next);
+    for(i = 0; i < ctx->baller_count; i++)
+      DEBUGASSERT(!ctx->ballers[i].cf);
+    CURL_TRC_CF(data, cf, "connect, init");
+    ctx->started = now;
+    cf_hc_baller_init(&ctx->ballers[0], cf, data, ctx->ballers[0].transport);
+    if(ctx->baller_count > 1) {
+      Curl_expire(data, ctx->soft_eyeballs_timeout_ms, EXPIRE_ALPN_EYEBALLS);
+      CURL_TRC_CF(data, cf, "set next attempt to start in %" FMT_TIMEDIFF_T
+                  "ms", ctx->soft_eyeballs_timeout_ms);
+    }
+    ctx->state = CF_HC_CONNECT;
+    FALLTHROUGH();
+
+  case CF_HC_CONNECT:
+    if(cf_hc_baller_is_active(&ctx->ballers[0])) {
+      result = cf_hc_baller_connect(&ctx->ballers[0], cf, data, done);
+      if(!result && *done) {
+        result = baller_connected(cf, data, &ctx->ballers[0]);
+        goto out;
+      }
+    }
+
+    if(time_to_start_next(cf, data, 1, now)) {
+      cf_hc_baller_init(&ctx->ballers[1], cf, data, ctx->ballers[1].transport);
+    }
+
+    if((ctx->baller_count > 1) && cf_hc_baller_is_active(&ctx->ballers[1])) {
+      CURL_TRC_CF(data, cf, "connect, check %s", ctx->ballers[1].name);
+      result = cf_hc_baller_connect(&ctx->ballers[1], cf, data, done);
+      if(!result && *done) {
+        result = baller_connected(cf, data, &ctx->ballers[1]);
+        goto out;
+      }
+    }
+
+    failed_ballers = 0;
+    for(i = 0; i < ctx->baller_count; i++) {
+      if(ctx->ballers[i].result)
+        ++failed_ballers;
+    }
+
+    if(failed_ballers == ctx->baller_count) {
+      /* all have failed. we give up */
+      CURL_TRC_CF(data, cf, "connect, all attempts failed");
+      for(i = 0; i < ctx->baller_count; i++) {
+        if(ctx->ballers[i].result) {
+          result = ctx->ballers[i].result;
+          break;
+        }
+      }
+      ctx->state = CF_HC_FAILURE;
+      goto out;
+    }
+    result = CURLE_OK;
+    *done = FALSE;
+    break;
+
+  case CF_HC_FAILURE:
+    result = ctx->result;
+    cf->connected = FALSE;
+    *done = FALSE;
+    break;
+
+  case CF_HC_SUCCESS:
+    result = CURLE_OK;
+    cf->connected = TRUE;
+    *done = TRUE;
+    break;
+  }
+
+out:
+  CURL_TRC_CF(data, cf, "connect -> %d, done=%d", result, *done);
+  return result;
+}
+
+static CURLcode cf_hc_shutdown(struct Curl_cfilter *cf,
+                               struct Curl_easy *data, bool *done)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  size_t i;
+  CURLcode result = CURLE_OK;
+
+  DEBUGASSERT(data);
+  if(cf->connected) {
+    *done = TRUE;
+    return CURLE_OK;
+  }
+
+  /* shutdown all ballers that have not done so already. If one fails,
+   * continue shutting down others until all are shutdown. */
+  for(i = 0; i < ctx->baller_count; i++) {
+    struct cf_hc_baller *b = &ctx->ballers[i];
+    bool bdone = FALSE;
+    if(!cf_hc_baller_is_active(b) || b->shutdown)
+      continue;
+    b->result = b->cf->cft->do_shutdown(b->cf, data, &bdone);
+    if(b->result || bdone)
+      b->shutdown = TRUE; /* treat a failed shutdown as done */
+  }
+
+  *done = TRUE;
+  for(i = 0; i < ctx->baller_count; i++) {
+    if(!ctx->ballers[i].shutdown)
+      *done = FALSE;
+  }
+  if(*done) {
+    for(i = 0; i < ctx->baller_count; i++) {
+      if(ctx->ballers[i].result)
+        result = ctx->ballers[i].result;
+    }
+  }
+  CURL_TRC_CF(data, cf, "shutdown -> %d, done=%d", result, *done);
+  return result;
+}
+
+static CURLcode cf_hc_adjust_pollset(struct Curl_cfilter *cf,
+                                     struct Curl_easy *data,
+                                     struct easy_pollset *ps)
+{
+  CURLcode result = CURLE_OK;
+  if(!cf->connected) {
+    struct cf_hc_ctx *ctx = cf->ctx;
+    size_t i;
+
+    for(i = 0; (i < ctx->baller_count) && !result; i++) {
+      struct cf_hc_baller *b = &ctx->ballers[i];
+      if(!cf_hc_baller_is_active(b))
+        continue;
+      result = Curl_conn_cf_adjust_pollset(b->cf, data, ps);
+    }
+    CURL_TRC_CF(data, cf, "adjust_pollset -> %d, %d socks", result, ps->n);
+  }
+  return result;
+}
+
+static bool cf_hc_data_pending(struct Curl_cfilter *cf,
+                               const struct Curl_easy *data)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  size_t i;
+
+  if(cf->connected)
+    return cf->next->cft->has_data_pending(cf->next, data);
+
+  for(i = 0; i < ctx->baller_count; i++)
+    if(cf_hc_baller_data_pending(&ctx->ballers[i], data))
+      return TRUE;
+  return FALSE;
+}
+
+static struct curltime cf_get_max_baller_time(struct Curl_cfilter *cf,
+                                              struct Curl_easy *data,
+                                              int query)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  struct curltime t, tmax;
+  size_t i;
+
+  memset(&tmax, 0, sizeof(tmax));
+  for(i = 0; i < ctx->baller_count; i++) {
+    struct Curl_cfilter *cfb = ctx->ballers[i].cf;
+    memset(&t, 0, sizeof(t));
+    if(cfb && !cfb->cft->query(cfb, data, query, NULL, &t)) {
+      if((t.tv_sec || t.tv_usec) && curlx_timediff_us(t, tmax) > 0)
+        tmax = t;
+    }
+  }
+  return tmax;
+}
+
+static CURLcode cf_hc_query(struct Curl_cfilter *cf,
+                            struct Curl_easy *data,
+                            int query, int *pres1, void *pres2)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  size_t i;
+
+  if(!cf->connected) {
+    switch(query) {
+    case CF_QUERY_TIMER_CONNECT: {
+      struct curltime *when = pres2;
+      *when = cf_get_max_baller_time(cf, data, CF_QUERY_TIMER_CONNECT);
+      return CURLE_OK;
+    }
+    case CF_QUERY_TIMER_APPCONNECT: {
+      struct curltime *when = pres2;
+      *when = cf_get_max_baller_time(cf, data, CF_QUERY_TIMER_APPCONNECT);
+      return CURLE_OK;
+    }
+    case CF_QUERY_NEED_FLUSH: {
+      for(i = 0; i < ctx->baller_count; i++)
+        if(cf_hc_baller_needs_flush(&ctx->ballers[i], data)) {
+          *pres1 = TRUE;
+          return CURLE_OK;
+        }
+      break;
+    }
+    default:
+      break;
+    }
+  }
+  return cf->next ?
+    cf->next->cft->query(cf->next, data, query, pres1, pres2) :
+    CURLE_UNKNOWN_OPTION;
+}
+
+static CURLcode cf_hc_cntrl(struct Curl_cfilter *cf,
+                            struct Curl_easy *data,
+                            int event, int arg1, void *arg2)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+  CURLcode result = CURLE_OK;
+  size_t i;
+
+  if(!cf->connected) {
+    for(i = 0; i < ctx->baller_count; i++) {
+      result = cf_hc_baller_cntrl(&ctx->ballers[i], data, event, arg1, arg2);
+      if(result && (result != CURLE_AGAIN))
+        goto out;
+    }
+    result = CURLE_OK;
+  }
+out:
+  return result;
+}
+
+static void cf_hc_close(struct Curl_cfilter *cf, struct Curl_easy *data)
+{
+  CURL_TRC_CF(data, cf, "close");
+  cf_hc_reset(cf, data);
+  cf->connected = FALSE;
+
+  if(cf->next) {
+    cf->next->cft->do_close(cf->next, data);
+    Curl_conn_cf_discard_chain(&cf->next, data);
+  }
+}
+
+static void cf_hc_destroy(struct Curl_cfilter *cf, struct Curl_easy *data)
+{
+  struct cf_hc_ctx *ctx = cf->ctx;
+
+  (void)data;
+  CURL_TRC_CF(data, cf, "destroy");
+  cf_hc_reset(cf, data);
+  Curl_safefree(ctx);
+}
+
+struct Curl_cftype Curl_cft_http_connect = {
+  "HTTPS-CONNECT",
+  0,
+  CURL_LOG_LVL_NONE,
+  cf_hc_destroy,
+  cf_hc_connect,
+  cf_hc_close,
+  cf_hc_shutdown,
+  cf_hc_adjust_pollset,
+  cf_hc_data_pending,
+  Curl_cf_def_send,
+  Curl_cf_def_recv,
+  cf_hc_cntrl,
+  Curl_cf_def_conn_is_alive,
+  Curl_cf_def_conn_keep_alive,
+  cf_hc_query,
+};
+
+static CURLcode cf_hc_create(struct Curl_cfilter **pcf,
+                             struct Curl_easy *data,
+                             enum alpnid *alpnids, size_t alpn_count,
+                             unsigned char def_transport)
+{
+  struct Curl_cfilter *cf = NULL;
+  struct cf_hc_ctx *ctx;
+  CURLcode result = CURLE_OK;
+  size_t i;
+
+  DEBUGASSERT(alpnids);
+  DEBUGASSERT(alpn_count);
+  DEBUGASSERT(alpn_count <= CURL_ARRAYSIZE(ctx->ballers));
+  if(!alpn_count || (alpn_count > CURL_ARRAYSIZE(ctx->ballers))) {
+    failf(data, "https-connect filter create with unsupported %zu ALPN ids",
+          alpn_count);
+    return CURLE_FAILED_INIT;
+  }
+
+  ctx = calloc(1, sizeof(*ctx));
+  if(!ctx) {
+    result = CURLE_OUT_OF_MEMORY;
+    goto out;
+  }
+  for(i = 0; i < alpn_count; ++i)
+    cf_hc_baller_assign(&ctx->ballers[i], alpnids[i], def_transport);
+  for(; i < CURL_ARRAYSIZE(ctx->ballers); ++i)
+    ctx->ballers[i].alpn_id = ALPN_none;
+  ctx->baller_count = alpn_count;
+
+  result = Curl_cf_create(&cf, &Curl_cft_http_connect, ctx);
+  if(result)
+    goto out;
+  ctx = NULL;
+  cf_hc_reset(cf, data);
+
+out:
+  *pcf = result ? NULL : cf;
+  free(ctx);
+  return result;
+}
+
+static CURLcode cf_http_connect_add(struct Curl_easy *data,
+                                    struct connectdata *conn,
+                                    int sockindex,
+                                    enum alpnid *alpn_ids, size_t alpn_count,
+                                    unsigned char def_transport)
+{
+  struct Curl_cfilter *cf;
+  CURLcode result = CURLE_OK;
+
+  DEBUGASSERT(data);
+  result = cf_hc_create(&cf, data, alpn_ids, alpn_count, def_transport);
+  if(result)
+    goto out;
+  Curl_conn_cf_add(data, conn, sockindex, cf);
+out:
+  return result;
+}
+
+static bool cf_https_alpns_contain(enum alpnid id,
+                                   enum alpnid *list, size_t len)
+{
+  size_t i;
+  for(i = 0; i < len; ++i) {
+    if(id == list[i])
+      return TRUE;
+  }
+  return FALSE;
+}
+
+CURLcode Curl_cf_https_setup(struct Curl_easy *data,
+                             struct connectdata *conn,
+                             int sockindex)
+{
+  enum alpnid alpn_ids[2];
+  size_t alpn_count = 0;
+  CURLcode result = CURLE_OK;
+  struct Curl_cfilter cf_fake, *cf = NULL;
+
+  (void)sockindex;
+  /* we want to log for the filter before we create it, fake it. */
+  memset(&cf_fake, 0, sizeof(cf_fake));
+  cf_fake.cft = &Curl_cft_http_connect;
+  cf = &cf_fake;
+
+  if(conn->bits.tls_enable_alpn) {
+#ifdef USE_HTTPSRR
+    /* Is there an HTTPSRR use its ALPNs here.
+     * We are here after having selected a connection to a host+port and
+     * can no longer change that. Any HTTPSRR advice for other hosts and ports
+     * we need to ignore. */
+    struct Curl_dns_entry *dns = data->state.dns[sockindex];
+    struct Curl_https_rrinfo *rr = dns ? dns->hinfo : NULL;
+    if(rr && !rr->no_def_alpn &&  /* ALPNs are defaults */
+       (!rr->target ||      /* for same host */
+        !rr->target[0] ||
+        (rr->target[0] == '.' &&
+         !rr->target[1])) &&
+       (rr->port < 0 ||    /* for same port */
+        rr->port == conn->remote_port)) {
+      size_t i;
+      for(i = 0; i < CURL_ARRAYSIZE(rr->alpns) &&
+                 alpn_count < CURL_ARRAYSIZE(alpn_ids); ++i) {
+        enum alpnid alpn = rr->alpns[i];
+        if(cf_https_alpns_contain(alpn, alpn_ids, alpn_count))
+          continue;
+        switch(alpn) {
+        case ALPN_h3:
+          if(Curl_conn_may_http3(data, conn, conn->transport_wanted))
+            break;  /* not possible */
+          if(data->state.http_neg.allowed & CURL_HTTP_V3x) {
+            CURL_TRC_CF(data, cf, "adding h3 via HTTPS-RR");
+            alpn_ids[alpn_count++] = alpn;
+          }
+          break;
+        case ALPN_h2:
+          if(data->state.http_neg.allowed & CURL_HTTP_V2x) {
+            CURL_TRC_CF(data, cf, "adding h2 via HTTPS-RR");
+            alpn_ids[alpn_count++] = alpn;
+          }
+          break;
+        case ALPN_h1:
+          if(data->state.http_neg.allowed & CURL_HTTP_V1x) {
+            CURL_TRC_CF(data, cf, "adding h1 via HTTPS-RR");
+            alpn_ids[alpn_count++] = alpn;
+          }
+          break;
+        default: /* ignore */
+          break;
+        }
+      }
+    }
+#endif
+
+    if((alpn_count < CURL_ARRAYSIZE(alpn_ids)) &&
+       (data->state.http_neg.wanted & CURL_HTTP_V3x) &&
+       !cf_https_alpns_contain(ALPN_h3, alpn_ids, alpn_count)) {
+      result = Curl_conn_may_http3(data, conn, conn->transport_wanted);
+      if(!result) {
+        CURL_TRC_CF(data, cf, "adding wanted h3");
+        alpn_ids[alpn_count++] = ALPN_h3;
+      }
+      else if(data->state.http_neg.wanted == CURL_HTTP_V3x)
+        goto out; /* only h3 allowed, not possible, error out */
+    }
+    if((alpn_count < CURL_ARRAYSIZE(alpn_ids)) &&
+       (data->state.http_neg.wanted & CURL_HTTP_V2x) &&
+       !cf_https_alpns_contain(ALPN_h2, alpn_ids, alpn_count)) {
+      CURL_TRC_CF(data, cf, "adding wanted h2");
+      alpn_ids[alpn_count++] = ALPN_h2;
+    }
+    else if((alpn_count < CURL_ARRAYSIZE(alpn_ids)) &&
+            (data->state.http_neg.wanted & CURL_HTTP_V1x) &&
+            !cf_https_alpns_contain(ALPN_h1, alpn_ids, alpn_count)) {
+      CURL_TRC_CF(data, cf, "adding wanted h1");
+      alpn_ids[alpn_count++] = ALPN_h1;
+    }
+  }
+
+  /* If we identified ALPNs to use, install our filter. Otherwise,
+   * install nothing, so our call will use a default connect setup. */
+  if(alpn_count) {
+    result = cf_http_connect_add(data, conn, sockindex,
+                                 alpn_ids, alpn_count,
+                                 conn->transport_wanted);
+  }
+
+out:
+  return result;
+}
+
+#endif /* !CURL_DISABLE_HTTP */