/***************************************************************************

 *                                  _   _ ____  _

 *  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"

#ifdef HAVE_NETINET_UDP_H

#include <netinet/udp.h>

#endif

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#include "../urldata.h"

#include "../bufq.h"

#include "../curlx/dynbuf.h"

#include "../cfilters.h"

#include "../curl_trc.h"

#include "curl_msh3.h"

#include "curl_ngtcp2.h"

#include "curl_osslq.h"

#include "curl_quiche.h"

#include "../multiif.h"

#include "../rand.h"

#include "vquic.h"

#include "vquic_int.h"

#include "../strerror.h"

#include "../curlx/strparse.h"

/* The last 3 #include files should be in this order */

#include "../curl_printf.h"

#include "../curl_memory.h"

#include "../memdebug.h"

#ifdef USE_HTTP3

#define NW_CHUNK_SIZE     (64 * 1024)

#define NW_SEND_CHUNKS    2

int Curl_vquic_init(void)

{

#if defined(USE_NGTCP2) && defined(OPENSSL_QUIC_API2)

  if(ngtcp2_crypto_ossl_init())

    return 0;

#endif

  return 1;

}

void Curl_quic_ver(char *p, size_t len)

{

#if defined(USE_NGTCP2) && defined(USE_NGHTTP3)

  Curl_ngtcp2_ver(p, len);

#elif defined(USE_OPENSSL_QUIC) && defined(USE_NGHTTP3)

  Curl_osslq_ver(p, len);

#elif defined(USE_QUICHE)

  Curl_quiche_ver(p, len);

#elif defined(USE_MSH3)

  Curl_msh3_ver(p, len);

#endif

}

CURLcode vquic_ctx_init(struct cf_quic_ctx *qctx)

{

  Curl_bufq_init2(&qctx->sendbuf, NW_CHUNK_SIZE, NW_SEND_CHUNKS,

                  BUFQ_OPT_SOFT_LIMIT);

#if defined(__linux__) && defined(UDP_SEGMENT) && defined(HAVE_SENDMSG)

  qctx->no_gso = FALSE;

#else

  qctx->no_gso = TRUE;

#endif

#ifdef DEBUGBUILD

  {

    const char *p = getenv("CURL_DBG_QUIC_WBLOCK");

    if(p) {

      curl_off_t l;

      if(!curlx_str_number(&p, &l, 100))

        qctx->wblock_percent = (int)l;

    }

  }

#endif

  vquic_ctx_update_time(qctx);

  return CURLE_OK;

}

void vquic_ctx_free(struct cf_quic_ctx *qctx)

{

  Curl_bufq_free(&qctx->sendbuf);

}

void vquic_ctx_update_time(struct cf_quic_ctx *qctx)

{

  qctx->last_op = curlx_now();

}

static CURLcode send_packet_no_gso(struct Curl_cfilter *cf,

                                   struct Curl_easy *data,

                                   struct cf_quic_ctx *qctx,

                                   const uint8_t *pkt, size_t pktlen,

                                   size_t gsolen, size_t *psent);

static CURLcode do_sendmsg(struct Curl_cfilter *cf,

                           struct Curl_easy *data,

                           struct cf_quic_ctx *qctx,

                           const uint8_t *pkt, size_t pktlen, size_t gsolen,

                           size_t *psent)

{

#ifdef HAVE_SENDMSG

  struct iovec msg_iov;

  struct msghdr msg = {0};

  ssize_t sent;

#if defined(__linux__) && defined(UDP_SEGMENT)

  uint8_t msg_ctrl[32];

  struct cmsghdr *cm;

#endif

  *psent = 0;

  msg_iov.iov_base = (uint8_t *)CURL_UNCONST(pkt);

  msg_iov.iov_len = pktlen;

  msg.msg_iov = &msg_iov;

  msg.msg_iovlen = 1;

#if defined(__linux__) && defined(UDP_SEGMENT)

  if(pktlen > gsolen) {

    /* Only set this, when we need it. macOS, for example,

     * does not seem to like a msg_control of length 0. */

    msg.msg_control = msg_ctrl;

    assert(sizeof(msg_ctrl) >= CMSG_SPACE(sizeof(int)));

    msg.msg_controllen = CMSG_SPACE(sizeof(int));

    cm = CMSG_FIRSTHDR(&msg);

    cm->cmsg_level = SOL_UDP;

    cm->cmsg_type = UDP_SEGMENT;

    cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));

    *(uint16_t *)(void *)CMSG_DATA(cm) = gsolen & 0xffff;

  }

#endif

  while((sent = sendmsg(qctx->sockfd, &msg, 0)) == -1 &&

        SOCKERRNO == SOCKEINTR)

    ;

  if(sent == -1) {

    switch(SOCKERRNO) {

    case EAGAIN:

#if EAGAIN != SOCKEWOULDBLOCK

    case SOCKEWOULDBLOCK:

#endif

      return CURLE_AGAIN;

    case SOCKEMSGSIZE:

      /* UDP datagram is too large; caused by PMTUD. Just let it be lost. */

      break;

    case EIO:

      if(pktlen > gsolen) {

        /* GSO failure */

        infof(data, "sendmsg() returned %zd (errno %d); disable GSO", sent,

              SOCKERRNO);

        qctx->no_gso = TRUE;

        return send_packet_no_gso(cf, data, qctx, pkt, pktlen, gsolen, psent);

      }

      FALLTHROUGH();

    default:

      failf(data, "sendmsg() returned %zd (errno %d)", sent, SOCKERRNO);

      return CURLE_SEND_ERROR;

    }

  }

  else {

    assert(pktlen == (size_t)sent);

  }

#else

  ssize_t sent;

  (void)gsolen;

  *psent = 0;

  while((sent = send(qctx->sockfd,

                     (const char *)pkt, (SEND_TYPE_ARG3)pktlen, 0)) == -1 &&

        SOCKERRNO == SOCKEINTR)

    ;

  if(sent == -1) {

    if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {

      return CURLE_AGAIN;

    }

    else {

      failf(data, "send() returned %zd (errno %d)", sent, SOCKERRNO);

      if(SOCKERRNO != SOCKEMSGSIZE) {

        return CURLE_SEND_ERROR;

      }

      /* UDP datagram is too large; caused by PMTUD. Just let it be

         lost. */

    }

  }

#endif

  (void)cf;

  *psent = pktlen;

  return CURLE_OK;

}

static CURLcode send_packet_no_gso(struct Curl_cfilter *cf,

                                   struct Curl_easy *data,

                                   struct cf_quic_ctx *qctx,

                                   const uint8_t *pkt, size_t pktlen,

                                   size_t gsolen, size_t *psent)

{

  const uint8_t *p, *end = pkt + pktlen;

  size_t sent;

  *psent = 0;

  for(p = pkt; p < end; p += gsolen) {

    size_t len = CURLMIN(gsolen, (size_t)(end - p));

    CURLcode curlcode = do_sendmsg(cf, data, qctx, p, len, len, &sent);

    if(curlcode != CURLE_OK) {

      return curlcode;

    }

    *psent += sent;

  }

  return CURLE_OK;

}

static CURLcode vquic_send_packets(struct Curl_cfilter *cf,

                                   struct Curl_easy *data,

                                   struct cf_quic_ctx *qctx,

                                   const uint8_t *pkt, size_t pktlen,

                                   size_t gsolen, size_t *psent)

{

  CURLcode result;

#ifdef DEBUGBUILD

  /* simulate network blocking/partial writes */

  if(qctx->wblock_percent > 0) {

    unsigned char c;

    *psent = 0;

    Curl_rand(data, &c, 1);

    if(c >= ((100-qctx->wblock_percent)*256/100)) {

      CURL_TRC_CF(data, cf, "vquic_flush() simulate EWOULDBLOCK");

      return CURLE_AGAIN;

    }

  }

#endif

  if(qctx->no_gso && pktlen > gsolen) {

    result = send_packet_no_gso(cf, data, qctx, pkt, pktlen, gsolen, psent);

  }

  else {

    result = do_sendmsg(cf, data, qctx, pkt, pktlen, gsolen, psent);

  }

  if(!result)

    qctx->last_io = qctx->last_op;

  return result;

}

CURLcode vquic_flush(struct Curl_cfilter *cf, struct Curl_easy *data,

                     struct cf_quic_ctx *qctx)

{

  const unsigned char *buf;

  size_t blen, sent;

  CURLcode result;

  size_t gsolen;

  while(Curl_bufq_peek(&qctx->sendbuf, &buf, &blen)) {

    gsolen = qctx->gsolen;

    if(qctx->split_len) {

      gsolen = qctx->split_gsolen;

      if(blen > qctx->split_len)

        blen = qctx->split_len;

    }

    result = vquic_send_packets(cf, data, qctx, buf, blen, gsolen, &sent);

    CURL_TRC_CF(data, cf, "vquic_send(len=%zu, gso=%zu) -> %d, sent=%zu",

                blen, gsolen, result, sent);

    if(result) {

      if(result == CURLE_AGAIN) {

        Curl_bufq_skip(&qctx->sendbuf, sent);

        if(qctx->split_len)

          qctx->split_len -= sent;

      }

      return result;

    }

    Curl_bufq_skip(&qctx->sendbuf, sent);

    if(qctx->split_len)

      qctx->split_len -= sent;

  }

  return CURLE_OK;

}

CURLcode vquic_send(struct Curl_cfilter *cf, struct Curl_easy *data,

                        struct cf_quic_ctx *qctx, size_t gsolen)

{

  qctx->gsolen = gsolen;

  return vquic_flush(cf, data, qctx);

}

CURLcode vquic_send_tail_split(struct Curl_cfilter *cf, struct Curl_easy *data,

                               struct cf_quic_ctx *qctx, size_t gsolen,

                               size_t tail_len, size_t tail_gsolen)

{

  DEBUGASSERT(Curl_bufq_len(&qctx->sendbuf) > tail_len);

  qctx->split_len = Curl_bufq_len(&qctx->sendbuf) - tail_len;

  qctx->split_gsolen = gsolen;

  qctx->gsolen = tail_gsolen;

  CURL_TRC_CF(data, cf, "vquic_send_tail_split: [%zu gso=%zu][%zu gso=%zu]",

              qctx->split_len, qctx->split_gsolen,

              tail_len, qctx->gsolen);

  return vquic_flush(cf, data, qctx);

}

#if defined(HAVE_SENDMMSG) || defined(HAVE_SENDMSG)

static size_t vquic_msghdr_get_udp_gro(struct msghdr *msg)

{

  int gso_size = 0;

#if defined(__linux__) && defined(UDP_GRO)

  struct cmsghdr *cmsg;

  /* Workaround musl CMSG_NXTHDR issue */

#if defined(__clang__) && !defined(__GLIBC__)

#pragma clang diagnostic push

#pragma clang diagnostic ignored "-Wsign-compare"

#pragma clang diagnostic ignored "-Wcast-align"

#endif

  for(cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {

#if defined(__clang__) && !defined(__GLIBC__)

#pragma clang diagnostic pop

#endif

    if(cmsg->cmsg_level == SOL_UDP && cmsg->cmsg_type == UDP_GRO) {

      memcpy(&gso_size, CMSG_DATA(cmsg), sizeof(gso_size));

      break;

    }

  }

#endif

  (void)msg;

  return (size_t)gso_size;

}

#endif

#ifdef HAVE_SENDMMSG

static CURLcode recvmmsg_packets(struct Curl_cfilter *cf,

                                 struct Curl_easy *data,

                                 struct cf_quic_ctx *qctx,

                                 size_t max_pkts,

                                 vquic_recv_pkt_cb *recv_cb, void *userp)

{

#define MMSG_NUM  16

  struct iovec msg_iov[MMSG_NUM];

  struct mmsghdr mmsg[MMSG_NUM];

  uint8_t msg_ctrl[MMSG_NUM * CMSG_SPACE(sizeof(int))];

  struct sockaddr_storage remote_addr[MMSG_NUM];

  size_t total_nread = 0, pkts = 0;

  int mcount, i, n;

  char errstr[STRERROR_LEN];

  CURLcode result = CURLE_OK;

  size_t gso_size;

  size_t pktlen;

  size_t offset, to;

  char *sockbuf = NULL;

  uint8_t (*bufs)[64*1024] = NULL;

  DEBUGASSERT(max_pkts > 0);

  result = Curl_multi_xfer_sockbuf_borrow(data, MMSG_NUM * sizeof(bufs[0]),

                                          &sockbuf);

  if(result)

    goto out;

  bufs = (uint8_t (*)[64*1024])sockbuf;

  total_nread = 0;

  while(pkts < max_pkts) {

    n = (int)CURLMIN(CURLMIN(MMSG_NUM, IOV_MAX), max_pkts);

    memset(&mmsg, 0, sizeof(mmsg));

    for(i = 0; i < n; ++i) {

      msg_iov[i].iov_base = bufs[i];

      msg_iov[i].iov_len = (int)sizeof(bufs[i]);

      mmsg[i].msg_hdr.msg_iov = &msg_iov[i];

      mmsg[i].msg_hdr.msg_iovlen = 1;

      mmsg[i].msg_hdr.msg_name = &remote_addr[i];

      mmsg[i].msg_hdr.msg_namelen = sizeof(remote_addr[i]);

      mmsg[i].msg_hdr.msg_control = &msg_ctrl[i * CMSG_SPACE(sizeof(int))];

      mmsg[i].msg_hdr.msg_controllen = CMSG_SPACE(sizeof(int));

    }

    while((mcount = recvmmsg(qctx->sockfd, mmsg, n, 0, NULL)) == -1 &&

          SOCKERRNO == SOCKEINTR)

      ;

    if(mcount == -1) {

      if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {

        CURL_TRC_CF(data, cf, "ingress, recvmmsg -> EAGAIN");

        goto out;

      }

      if(!cf->connected && SOCKERRNO == SOCKECONNREFUSED) {

        struct ip_quadruple ip;

        Curl_cf_socket_peek(cf->next, data, NULL, NULL, &ip);

        failf(data, "QUIC: connection to %s port %u refused",

              ip.remote_ip, ip.remote_port);

        result = CURLE_COULDNT_CONNECT;

        goto out;

      }

      Curl_strerror(SOCKERRNO, errstr, sizeof(errstr));

      failf(data, "QUIC: recvmsg() unexpectedly returned %d (errno=%d; %s)",

                  mcount, SOCKERRNO, errstr);

      result = CURLE_RECV_ERROR;

      goto out;

    }

    CURL_TRC_CF(data, cf, "recvmmsg() -> %d packets", mcount);

    for(i = 0; i < mcount; ++i) {

      total_nread += mmsg[i].msg_len;

      gso_size = vquic_msghdr_get_udp_gro(&mmsg[i].msg_hdr);

      if(gso_size == 0) {

        gso_size = mmsg[i].msg_len;

      }

      for(offset = 0; offset < mmsg[i].msg_len; offset = to) {

        ++pkts;

        to = offset + gso_size;

        if(to > mmsg[i].msg_len) {

          pktlen = mmsg[i].msg_len - offset;

        }

        else {

          pktlen = gso_size;

        }

        result = recv_cb(bufs[i] + offset, pktlen, mmsg[i].msg_hdr.msg_name,

                         mmsg[i].msg_hdr.msg_namelen, 0, userp);

        if(result)

          goto out;

      }

    }

  }

out:

  if(total_nread || result)

    CURL_TRC_CF(data, cf, "recvd %zu packets with %zu bytes -> %d",

                pkts, total_nread, result);

  Curl_multi_xfer_sockbuf_release(data, sockbuf);

  return result;

}

#elif defined(HAVE_SENDMSG)

static CURLcode recvmsg_packets(struct Curl_cfilter *cf,

                                struct Curl_easy *data,

                                struct cf_quic_ctx *qctx,

                                size_t max_pkts,

                                vquic_recv_pkt_cb *recv_cb, void *userp)

{

  struct iovec msg_iov;

  struct msghdr msg;

  uint8_t buf[64*1024];

  struct sockaddr_storage remote_addr;

  size_t total_nread, pkts;

  ssize_t nread;

  char errstr[STRERROR_LEN];

  CURLcode result = CURLE_OK;

  uint8_t msg_ctrl[CMSG_SPACE(sizeof(int))];

  size_t gso_size;

  size_t pktlen;

  size_t offset, to;

  DEBUGASSERT(max_pkts > 0);

  for(pkts = 0, total_nread = 0; pkts < max_pkts;) {

    /* fully initialise this on each call to `recvmsg()`. There seem to

     * operating systems out there that mess with `msg_iov.iov_len`. */

    memset(&msg, 0, sizeof(msg));

    msg_iov.iov_base = buf;

    msg_iov.iov_len = (int)sizeof(buf);

    msg.msg_iov = &msg_iov;

    msg.msg_iovlen = 1;

    msg.msg_control = msg_ctrl;

    msg.msg_name = &remote_addr;

    msg.msg_namelen = sizeof(remote_addr);

    msg.msg_controllen = sizeof(msg_ctrl);

    while((nread = recvmsg(qctx->sockfd, &msg, 0)) == -1 &&

          SOCKERRNO == SOCKEINTR)

      ;

    if(nread == -1) {

      if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {

        goto out;

      }

      if(!cf->connected && SOCKERRNO == SOCKECONNREFUSED) {

        struct ip_quadruple ip;

        Curl_cf_socket_peek(cf->next, data, NULL, NULL, &ip);

        failf(data, "QUIC: connection to %s port %u refused",

              ip.remote_ip, ip.remote_port);

        result = CURLE_COULDNT_CONNECT;

        goto out;

      }

      Curl_strerror(SOCKERRNO, errstr, sizeof(errstr));

      failf(data, "QUIC: recvmsg() unexpectedly returned %zd (errno=%d; %s)",

                  nread, SOCKERRNO, errstr);

      result = CURLE_RECV_ERROR;

      goto out;

    }

    total_nread += (size_t)nread;

    gso_size = vquic_msghdr_get_udp_gro(&msg);

    if(gso_size == 0) {

      gso_size = (size_t)nread;

    }

    for(offset = 0; offset < (size_t)nread; offset = to) {

      ++pkts;

      to = offset + gso_size;

      if(to > (size_t)nread) {

        pktlen = (size_t)nread - offset;

      }

      else {

        pktlen = gso_size;

      }

      result =

        recv_cb(buf + offset, pktlen, msg.msg_name, msg.msg_namelen, 0, userp);

      if(result)

        goto out;

    }

  }

out:

  if(total_nread || result)

    CURL_TRC_CF(data, cf, "recvd %zu packets with %zu bytes -> %d",

                pkts, total_nread, result);

  return result;

}

#else /* HAVE_SENDMMSG || HAVE_SENDMSG */

static CURLcode recvfrom_packets(struct Curl_cfilter *cf,

                                 struct Curl_easy *data,

                                 struct cf_quic_ctx *qctx,

                                 size_t max_pkts,

                                 vquic_recv_pkt_cb *recv_cb, void *userp)

{

  uint8_t buf[64*1024];

  int bufsize = (int)sizeof(buf);

  struct sockaddr_storage remote_addr;

  socklen_t remote_addrlen = sizeof(remote_addr);

  size_t total_nread, pkts;

  ssize_t nread;

  char errstr[STRERROR_LEN];

  CURLcode result = CURLE_OK;

  DEBUGASSERT(max_pkts > 0);

  for(pkts = 0, total_nread = 0; pkts < max_pkts;) {

    while((nread = recvfrom(qctx->sockfd, (char *)buf, bufsize, 0,

                            (struct sockaddr *)&remote_addr,

                            &remote_addrlen)) == -1 &&

          SOCKERRNO == SOCKEINTR)

      ;

    if(nread == -1) {

      if(SOCKERRNO == EAGAIN || SOCKERRNO == SOCKEWOULDBLOCK) {

        CURL_TRC_CF(data, cf, "ingress, recvfrom -> EAGAIN");

        goto out;

      }

      if(!cf->connected && SOCKERRNO == SOCKECONNREFUSED) {

        struct ip_quadruple ip;

        Curl_cf_socket_peek(cf->next, data, NULL, NULL, &ip);

        failf(data, "QUIC: connection to %s port %u refused",

              ip.remote_ip, ip.remote_port);

        result = CURLE_COULDNT_CONNECT;

        goto out;

      }

      Curl_strerror(SOCKERRNO, errstr, sizeof(errstr));

      failf(data, "QUIC: recvfrom() unexpectedly returned %zd (errno=%d; %s)",

                  nread, SOCKERRNO, errstr);

      result = CURLE_RECV_ERROR;

      goto out;

    }

    ++pkts;

    total_nread += (size_t)nread;

    result = recv_cb(buf, (size_t)nread, &remote_addr, remote_addrlen,

                     0, userp);

    if(result)

      goto out;

  }

out:

  if(total_nread || result)

    CURL_TRC_CF(data, cf, "recvd %zu packets with %zu bytes -> %d",

                pkts, total_nread, result);

  return result;

}

#endif /* !HAVE_SENDMMSG && !HAVE_SENDMSG */

CURLcode vquic_recv_packets(struct Curl_cfilter *cf,

                            struct Curl_easy *data,

                            struct cf_quic_ctx *qctx,

                            size_t max_pkts,

                            vquic_recv_pkt_cb *recv_cb, void *userp)

{

  CURLcode result;

#if defined(HAVE_SENDMMSG)

  result = recvmmsg_packets(cf, data, qctx, max_pkts, recv_cb, userp);

#elif defined(HAVE_SENDMSG)

  result = recvmsg_packets(cf, data, qctx, max_pkts, recv_cb, userp);

#else

  result = recvfrom_packets(cf, data, qctx, max_pkts, recv_cb, userp);

#endif

  if(!result) {

    if(!qctx->got_first_byte) {

      qctx->got_first_byte = TRUE;

      qctx->first_byte_at = qctx->last_op;

    }

    qctx->last_io = qctx->last_op;

  }

  return result;

}

/*

 * If the QLOGDIR environment variable is set, open and return a file

 * descriptor to write the log to.

 *

 * This function returns error if something failed outside of failing to

 * create the file. Open file success is deemed by seeing if the returned fd

 * is != -1.

 */

CURLcode Curl_qlogdir(struct Curl_easy *data,

                      unsigned char *scid,

                      size_t scidlen,

                      int *qlogfdp)

{

  const char *qlog_dir = getenv("QLOGDIR");

  *qlogfdp = -1;

  if(qlog_dir) {

    struct dynbuf fname;

    CURLcode result;

    unsigned int i;

    curlx_dyn_init(&fname, DYN_QLOG_NAME);

    result = curlx_dyn_add(&fname, qlog_dir);

    if(!result)

      result = curlx_dyn_add(&fname, "/");

    for(i = 0; (i < scidlen) && !result; i++) {

      char hex[3];

      msnprintf(hex, 3, "%02x", scid[i]);

      result = curlx_dyn_add(&fname, hex);

    }

    if(!result)

      result = curlx_dyn_add(&fname, ".sqlog");

    if(!result) {

      int qlogfd = open(curlx_dyn_ptr(&fname), O_WRONLY|O_CREAT|CURL_O_BINARY,

                        data->set.new_file_perms);

      if(qlogfd != -1)

        *qlogfdp = qlogfd;

    }

    curlx_dyn_free(&fname);

    if(result)

      return result;

  }

  return CURLE_OK;

}

CURLcode Curl_cf_quic_create(struct Curl_cfilter **pcf,

                             struct Curl_easy *data,

                             struct connectdata *conn,

                             const struct Curl_addrinfo *ai,

                             int transport)

{

  (void)transport;

  DEBUGASSERT(transport == TRNSPRT_QUIC);

#if defined(USE_NGTCP2) && defined(USE_NGHTTP3)

  return Curl_cf_ngtcp2_create(pcf, data, conn, ai);

#elif defined(USE_OPENSSL_QUIC) && defined(USE_NGHTTP3)

  return Curl_cf_osslq_create(pcf, data, conn, ai);

#elif defined(USE_QUICHE)

  return Curl_cf_quiche_create(pcf, data, conn, ai);

#elif defined(USE_MSH3)

  return Curl_cf_msh3_create(pcf, data, conn, ai);

#else

  *pcf = NULL;

  (void)data;

  (void)conn;

  (void)ai;

  return CURLE_NOT_BUILT_IN;

#endif

}

CURLcode Curl_conn_may_http3(struct Curl_easy *data,

                             const struct connectdata *conn)

{

  if(conn->transport == TRNSPRT_UNIX) {

    /* cannot do QUIC over a Unix domain socket */

    return CURLE_QUIC_CONNECT_ERROR;

  }

  if(!(conn->handler->flags & PROTOPT_SSL)) {

    failf(data, "HTTP/3 requested for non-HTTPS URL");

    return CURLE_URL_MALFORMAT;

  }

#ifndef CURL_DISABLE_PROXY

  if(conn->bits.socksproxy) {

    failf(data, "HTTP/3 is not supported over a SOCKS proxy");

    return CURLE_URL_MALFORMAT;

  }

  if(conn->bits.httpproxy && conn->bits.tunnel_proxy) {

    failf(data, "HTTP/3 is not supported over an HTTP proxy");

    return CURLE_URL_MALFORMAT;

  }

#endif

  return CURLE_OK;

}

#else /* USE_HTTP3 */

CURLcode Curl_conn_may_http3(struct Curl_easy *data,

                             const struct connectdata *conn)

{

  (void)conn;

  (void)data;

  DEBUGF(infof(data, "QUIC is not supported in this build"));

  return CURLE_NOT_BUILT_IN;

}

#endif /* !USE_HTTP3 */