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

 *                                  _   _ ____  _

 *  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

 *

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

/*

 * IDN conversions

 */

#include "curl_setup.h"

#ifdef HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef HAVE_NETDB_H

#include <netdb.h>

#endif

#ifdef HAVE_ARPA_INET_H

#include <arpa/inet.h>

#endif

#ifdef HAVE_NET_IF_H

#include <net/if.h>

#endif

#ifdef HAVE_IPHLPAPI_H

#include <Iphlpapi.h>

#endif

#ifdef HAVE_SYS_IOCTL_H

#include <sys/ioctl.h>

#endif

#ifdef HAVE_SYS_PARAM_H

#include <sys/param.h>

#endif

#ifdef __VMS

#include <in.h>

#include <inet.h>

#endif

#ifdef HAVE_SYS_UN_H

#include <sys/un.h>

#endif

#if defined(HAVE_IF_NAMETOINDEX) && defined(USE_WINSOCK)

#if defined(__MINGW32__) && (__MINGW64_VERSION_MAJOR <= 5)

#include <wincrypt.h>  /* workaround for old mingw-w64 missing to include it */

#endif

#include <iphlpapi.h>

#endif

#include "curl_addrinfo.h"

#include "curl_trc.h"

#include "protocol.h"

#include "http_proxy.h"

#include "idn.h"

#include "curlx/strdup.h"

#include "curlx/strparse.h"

#include "peer.h"

#include "urldata.h"

#include "url.h"

#include "urlapi-int.h"

#include "vtls/vtls.h"

struct peer_parse {

  const struct Curl_scheme *scheme;

  struct Curl_str host_user;

  struct Curl_str host;

  struct Curl_str zoneid;

  char *tmp_host_user;

  char *tmp_host;

  char *tmp_zoneid;

  uint32_t scopeid;

  uint16_t port;

  bool ipv6;

  bool unix_socket;

  bool abstract_uds;

};

static void peer_parse_clear(struct peer_parse *pp)

{

  curlx_free(pp->tmp_host_user);

  curlx_free(pp->tmp_host);

  curlx_free(pp->tmp_zoneid);

  memset(pp, 0, sizeof(*pp));

}

static CURLcode peer_create(struct peer_parse *pp,

                            struct Curl_peer **ppeer)

{

  struct Curl_peer *peer = NULL;

  CURLcode result = CURLE_OK;

  size_t zone_alen = 0, host_alen = 0;

  if(!pp || !pp->scheme)

    return CURLE_FAILED_INIT;

  if(!pp->host.len && !(pp->scheme->flags & PROTOPT_NONETWORK))

    return CURLE_FAILED_INIT;

  if((pp->host.str != pp->host_user.str) ||

     (pp->host.len != pp->host_user.len)) {

    host_alen = pp->host.len + 1;

  }

  zone_alen = pp->zoneid.len ? (pp->zoneid.len + 1) : 0;

  /* null-terminator already part of struct */

  peer = curlx_calloc(1, sizeof(*peer) +

                         pp->host_user.len + host_alen + zone_alen);

  if(!peer) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  peer->refcount = 1;

  peer->scheme = pp->scheme;

  peer->hostname = peer->user_hostname;

  peer->port = pp->port;

  peer->scopeid = pp->scopeid;

  peer->ipv6 = pp->ipv6;

  peer->unix_socket = pp->unix_socket;

  peer->abstract_uds = pp->abstract_uds;

  if(pp->host_user.len)

    memcpy(peer->user_hostname, pp->host_user.str, pp->host_user.len);

  if(host_alen) {

    peer->hostname = peer->user_hostname + pp->host_user.len + 1;

    memcpy(peer->hostname, pp->host.str, pp->host.len);

  }

  if(zone_alen) {

    peer->zoneid = peer->user_hostname + pp->host_user.len + 1 + host_alen;

    memcpy(peer->zoneid, pp->zoneid.str, pp->zoneid.len);

#ifdef USE_IPV6

    /* Determine scope_id if not already provided */

    if(!peer->scopeid) {

      const char *p = peer->zoneid;

      curl_off_t scope;

      if(!curlx_str_number(&p, &scope, UINT_MAX)) {

        /* A plain number, use it directly as a scope id. */

        peer->scopeid = (uint32_t)scope;

      }

#ifdef HAVE_IF_NAMETOINDEX

      else {

        /* Zone identifier is not numeric */

        unsigned int idx = 0;

        idx = if_nametoindex(peer->zoneid);

        if(idx) {

          peer->scopeid = (uint32_t)idx;

        }

        else {

          /* Do we want to return an error here? */

        }

      }

#endif /* HAVE_IF_NAMETOINDEX */

    }

#endif /* USE_IPV6 */

  }

out:

  if(!result)

    *ppeer = peer;

  else

    Curl_peer_unlink(&peer);

  return result;

}

static CURLcode peer_parse_host(struct Curl_easy *data,

                                struct peer_parse *pp,

                                bool scan_for_ipv6)

{

  if(!pp || !pp->host_user.str || !pp->host_user.len)

    return CURLE_FAILED_INIT;

  if(pp->host_user.str[0] == '[') {

    const char *s = pp->host_user.str + 1;

    struct Curl_str tmp;

    if(curlx_str_until(&s, &tmp, pp->host_user.len - 1, ']'))

      return CURLE_URL_MALFORMAT;

    if(!Curl_looks_like_ipv6(tmp.str, tmp.len, TRUE,

                             &pp->host, &pp->zoneid)) {

      failf(data, "Invalid IPv6 address format in '%.*s'",

            (int)pp->host_user.len, pp->host_user.str);

      return CURLE_URL_MALFORMAT;

    }

    pp->ipv6 = TRUE;

  }

  else {

#ifdef USE_IDN

    if(!Curl_is_ASCII_str(&pp->host_user)) {

      CURLcode result;

      if(!pp->tmp_host_user) {

        /* need a null-terminated string for IDN */

        pp->tmp_host_user = curlx_memdup0(pp->host_user.str,

                                          pp->host_user.len);

        if(!pp->tmp_host_user)

          return CURLE_OUT_OF_MEMORY;

      }

      result = Curl_idn_decode(pp->tmp_host_user, &pp->tmp_host);

      if(result)

        return result;

      pp->host.str = pp->tmp_host;

      pp->host.len = strlen(pp->host.str);

    }

    else

#endif

    if(scan_for_ipv6 &&

       Curl_looks_like_ipv6(pp->host_user.str, pp->host_user.len, TRUE,

                            &pp->host, &pp->zoneid)) {

      if(pp->host_user.len < MAX_IPADR_LEN) {

        char tmp[MAX_IPADR_LEN];

        memcpy(tmp, pp->host_user.str, pp->host_user.len);

        tmp[pp->host_user.len] = 0;

        pp->ipv6 = !Curl_is_ipv4addr(tmp);

      }

      else

        pp->ipv6 = TRUE;

    }

    else

      pp->host = pp->host_user;

  }

  return CURLE_OK;

}

CURLcode Curl_peer_create(struct Curl_easy *data,

                          const struct Curl_scheme *scheme,

                          const char *hostname,

                          uint16_t port,

                          struct Curl_peer **ppeer)

{

  struct peer_parse pp;

  CURLcode result;

  Curl_peer_unlink(ppeer);

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

  pp.scheme = scheme;

  pp.host_user.str = hostname;

  pp.host_user.len = strlen(hostname);

  pp.port = port;

  result = peer_parse_host(data, &pp, TRUE);

  if(!result)

    result = peer_create(&pp, ppeer);

  peer_parse_clear(&pp);

  return result;

}

#ifdef USE_UNIX_SOCKETS

CURLcode Curl_peer_uds_create(const struct Curl_scheme *scheme,

                              const char *path,

                              bool abstract_unix_socket,

                              struct Curl_peer **ppeer)

{

  struct peer_parse pp;

  size_t pathlen = path ? strlen(path) : 0;

  CURLcode result = CURLE_OK;

  Curl_peer_unlink(ppeer);

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

  if(!scheme)

    return CURLE_FAILED_INIT;

  if(!pathlen)

    return CURLE_FAILED_INIT;

  pp.scheme = scheme;

  pp.host_user.str = pp.host.str = path;

  pp.host_user.len = pp.host.len = pathlen;

  pp.unix_socket = TRUE;

  pp.abstract_uds = abstract_unix_socket;

  result = peer_create(&pp, ppeer);

  peer_parse_clear(&pp);

  return result;

}

#endif /* USE_UNIX_SOCKETS */

void Curl_peer_link(struct Curl_peer **pdest, struct Curl_peer *src)

{

  if(*pdest != src) {

    Curl_peer_unlink(pdest);

    *pdest = src;

    if(src) {

      DEBUGASSERT(src->refcount < UINT32_MAX);

      src->refcount++;

    }

  }

}

void Curl_peer_unlink(struct Curl_peer **ppeer)

{

  if(*ppeer) {

    struct Curl_peer *peer = *ppeer;

    DEBUGASSERT(peer->refcount);

    *ppeer = NULL;

    if(peer->refcount)

      peer->refcount--;

    if(!peer->refcount) {

      curlx_free(peer);

    }

  }

}

bool Curl_peer_equal(struct Curl_peer *p1, struct Curl_peer *p2)

{

  return (p1 == p2) ||

         (p1 && p2 &&

          (p1->scheme == p2->scheme) &&

          Curl_peer_same_destination(p1, p2));

}

static bool peer_same_hostname(struct Curl_peer *p1, struct Curl_peer *p2)

{

  /* UNIX domain socket paths must be compared case-sensitive,

   * as many filesystem are like that. */

  return (p1->unix_socket == p2->unix_socket) &&

         (p1->abstract_uds == p2->abstract_uds) &&

         (p1->ipv6 == p2->ipv6) &&

         (p1->unix_socket ?

          !strcmp(p1->hostname, p2->hostname) :

          curl_strequal(p1->hostname, p2->hostname));

}

bool Curl_peer_same_destination(struct Curl_peer *p1, struct Curl_peer *p2)

{

  return (p1 == p2) ||

         (p1 && p2 &&

          (p1->port == p2->port) &&

          peer_same_hostname(p1, p2) &&

          (p1->scopeid == p2->scopeid) &&

          (p1->scopeid || curl_strequal(p1->zoneid, p2->zoneid)));

}

CURLcode Curl_peer_from_url(CURLU *uh, struct Curl_easy *data,

                            uint16_t port_override,

                            uint32_t scopeid_override,

                            struct Curl_peer **ppeer)

{

  struct peer_parse pp;

  char *zoneid = NULL, *scheme = NULL, *hostname = NULL;

  CURLUcode uc;

  CURLcode result;

  Curl_peer_unlink(ppeer);

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

  uc = curl_url_get(uh, CURLUPART_SCHEME, &scheme, 0);

  if(uc)

    return Curl_uc_to_curlcode(uc);

  pp.scheme = Curl_get_scheme(scheme);

  if(!pp.scheme) {

    failf(data, "Protocol \"%s\" not supported%s", scheme,

          data->state.this_is_a_follow ? " (in redirect)" : "");

    result = CURLE_UNSUPPORTED_PROTOCOL;

    goto out;

  }

  uc = curl_url_get(uh, CURLUPART_HOST, &hostname, 0);

  if(uc) {

    if((uc == CURLUE_NO_HOST) && (pp.scheme->flags & PROTOPT_NONETWORK))

      ; /* acceptable */

    else {

      result = CURLE_OUT_OF_MEMORY;

      goto out;

    }

  }

  else if(strlen(hostname) > MAX_URL_LEN) {

    failf(data, "Too long hostname (maximum is %d)", MAX_URL_LEN);

    result = CURLE_URL_MALFORMAT;

    goto out;

  }

  pp.host_user.str = hostname ? hostname : "";

  pp.host_user.len = strlen(pp.host_user.str);

  if(pp.host_user.len) {

    result = peer_parse_host(data, &pp, FALSE);

    if(result)

      goto out;

  }

  else

    pp.host = pp.host_user;

  if(port_override) {

    /* if set, we use this instead of the port possibly given in the URL */

    char portbuf[16];

    curl_msnprintf(portbuf, sizeof(portbuf), "%d", port_override);

    uc = curl_url_set(uh, CURLUPART_PORT, portbuf, 0);

    if(uc) {

      result = CURLE_OUT_OF_MEMORY;

      goto out;

    }

    else

      pp.port = port_override;

  }

  else {

    uc = Curl_url_get_port(uh, &pp.port);

    if(uc) {

      if(uc == CURLUE_OUT_OF_MEMORY) {

        result = CURLE_OUT_OF_MEMORY;

        goto out;

      }

      else if(!(pp.scheme->flags & PROTOPT_NONETWORK)) {

        result = CURLE_URL_MALFORMAT;

        goto out;

      }

      /* no port ok when not a network scheme */

    }

  }

  if(scopeid_override)

    /* Override any scope id from an URL zone. */

    pp.scopeid = scopeid_override;

  else {

    if(curl_url_get(uh, CURLUPART_ZONEID, &zoneid, 0) ==

       CURLUE_OUT_OF_MEMORY) {

      result = CURLE_OUT_OF_MEMORY;

      goto out;

    }

    if(zoneid) {

      pp.zoneid.str = zoneid;

      pp.zoneid.len = strlen(zoneid);

    }

  }

  result = peer_create(&pp, ppeer);

  if(result)

    failf(data, "Error %d creating peer for %s:%u",

          (int)result, pp.host_user.str, pp.port);

out:

  peer_parse_clear(&pp);

  curlx_free(scheme);

  curlx_free(hostname);

  curlx_free(zoneid);

  return result;

}

/* Parse a "host:port" string to connect to into a peer.

 * IPv6 addresses might appear in brackets or without them. */

CURLcode Curl_peer_from_connect_to(struct Curl_easy *data,

                                   const struct Curl_peer *dest,

                                   const char *connect_to,

                                   struct Curl_peer **ppeer)

{

  struct peer_parse pp;

  const char *portstr = NULL;

  CURLcode result;

  Curl_peer_unlink(ppeer);

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

  if(!connect_to || !*connect_to)

    return CURLE_FAILED_INIT;

  pp.scheme = dest->scheme;

  /* detect and extract RFC6874-style IPv6-addresses */

  if(connect_to[0] == '[') {

    const char *s = strchr(connect_to + 1, ']');

    if(!s) {

      failf(data, "Invalid IPv6 address format in '%s'", connect_to);

      result = CURLE_SETOPT_OPTION_SYNTAX;

      goto out;

    }

    portstr = strchr(s, ':');

    pp.host_user.str = connect_to;

    pp.host_user.len = s - pp.host_user.str + 1;

    pp.ipv6 = TRUE;

  }

  else {

    portstr = strchr(connect_to, ':');

    pp.host_user.str = connect_to;

    pp.host_user.len = portstr ?

      (size_t)(portstr - connect_to) : strlen(connect_to);

  }

  if(!pp.host_user.len) { /* no hostname found, only port switch */

    pp.host_user.str = dest->user_hostname;

    pp.host_user.len = strlen(dest->user_hostname);

  }

  result = peer_parse_host(data, &pp, FALSE);

  if(result)

    goto out;

  if(portstr && portstr[1]) {

    const char *p = portstr + 1;

    curl_off_t portparse;

    if(curlx_str_number(&p, &portparse, 0xffff)) {

      failf(data, "No valid port number in '%s'", connect_to);

      result = CURLE_SETOPT_OPTION_SYNTAX;

      goto out;

    }

    pp.port = (uint16_t)portparse; /* we know it will fit */

  }

  else

    pp.port = dest->port;

#ifndef USE_IPV6

  if(pp.ipv6) {

    failf(data, "Use of IPv6 in *_CONNECT_TO without IPv6 support built-in");

    result = CURLE_NOT_BUILT_IN;

    goto out;

  }

#endif

  result = peer_create(&pp, ppeer);

  CURL_TRC_M(data, "connect-to peer_create2 -> %d", (int)result);

out:

  CURL_TRC_M(data, "parse connect_to peer: %s -> %d", connect_to, (int)result);

  peer_parse_clear(&pp);

  return result;

}

#ifndef CURL_DISABLE_PROXY

#ifdef USE_UNIX_SOCKETS

#define UNIX_SOCKET_PREFIX "localhost"

#endif

CURLcode Curl_scheme_to_proxytype(struct Curl_easy *data,

                                  const char *scheme,

                                  uint8_t *proxytype, const char *url)

{

  if(!scheme)

    return CURLE_OK;

  if(curl_strequal("https", scheme)) {

    if(*proxytype != CURLPROXY_HTTPS2 && *proxytype != CURLPROXY_HTTPS3)

      *proxytype = CURLPROXY_HTTPS;

  }

  else if(curl_strequal("socks5h", scheme))

    *proxytype = CURLPROXY_SOCKS5_HOSTNAME;

  else if(curl_strequal("socks5", scheme))

    *proxytype = CURLPROXY_SOCKS5;

  else if(curl_strequal("socks4a", scheme))

    *proxytype = CURLPROXY_SOCKS4A;

  else if(curl_strequal("socks4", scheme) || curl_strequal("socks", scheme))

    *proxytype = CURLPROXY_SOCKS4;

  else if(curl_strequal("http", scheme)) {

    if(*proxytype != CURLPROXY_HTTP_1_0)

      *proxytype = CURLPROXY_HTTP;

  }

  else {

    /* Any other xxx:// reject! */

    failf(data, "Unsupported proxy scheme for \'%s\'", url);

    return CURLE_COULDNT_CONNECT;

  }

  return CURLE_OK;

}

CURLcode Curl_peer_from_proxy_url(CURLU *uh,

                                  struct Curl_easy *data,

                                  const char *url,

                                  uint8_t proxytype,

                                  struct Curl_peer **ppeer,

                                  uint8_t *pproxytype)

{

  struct peer_parse pp;

  char *scheme = NULL;

  char *portptr = NULL;

#ifdef USE_UNIX_SOCKETS

  bool is_socks = FALSE;

#endif

  CURLUcode uc;

  CURLcode result = CURLE_OK;

  Curl_peer_unlink(ppeer);

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

  pp.port = CURL_DEFAULT_PROXY_PORT;

  uc = curl_url_get(uh, CURLUPART_SCHEME, &scheme,

                    CURLU_NON_SUPPORT_SCHEME | CURLU_NO_GUESS_SCHEME);

  if(uc) {

    if(uc == CURLUE_OUT_OF_MEMORY) {

      result = CURLE_OUT_OF_MEMORY;

      goto out;

    }

    /* URL came without scheme, the passed `proxytype` determines it */

    switch(proxytype) {

    case CURLPROXY_HTTP:

    case CURLPROXY_HTTP_1_0:

      pp.scheme = &Curl_scheme_http;

      break;

    case CURLPROXY_HTTPS:

    case CURLPROXY_HTTPS2:

    case CURLPROXY_HTTPS3:

      pp.scheme = &Curl_scheme_https;

      break;

    case CURLPROXY_SOCKS4:

      pp.scheme = &Curl_scheme_socks4;

      break;

    case CURLPROXY_SOCKS4A:

      pp.scheme = &Curl_scheme_socks4a;

      break;

    case CURLPROXY_SOCKS5:

      pp.scheme = &Curl_scheme_socks5;

      break;

    case CURLPROXY_SOCKS5_HOSTNAME:

      pp.scheme = &Curl_scheme_socks5h;

      break;

    default:

      failf(data, "Unsupported proxy type %u for \'%s\'", proxytype, url);

      result = CURLE_COULDNT_RESOLVE_PROXY;

      goto out;

    }

  }

  else {

    pp.scheme = Curl_get_scheme(scheme);

    result = Curl_scheme_to_proxytype(data, scheme, &proxytype, url);

    if(result)

      goto out;

  }

  DEBUGASSERT(pp.scheme);

  if(CURL_PROXY_IS_HTTPS(proxytype) &&

     !Curl_ssl_supports(data, SSLSUPP_HTTPS_PROXY)) {

    failf(data, "Unsupported proxy \'%s\', libcurl is built without the "

          "HTTPS-proxy support.", url);

    result = CURLE_NOT_BUILT_IN;

    goto out;

  }

  switch(pp.scheme->family) {

  case CURLPROTO_SOCKS:

#ifdef USE_UNIX_SOCKETS

    is_socks = TRUE;

#endif

    break;

  case CURLPROTO_HTTP:

    break;

  default:

    failf(data, "Unsupported proxy protocol for \'%s\'", url);

    result = CURLE_COULDNT_CONNECT;

    goto out;

  }

  uc = curl_url_get(uh, CURLUPART_PORT, &portptr, CURLU_NO_DEFAULT_PORT);

  if(uc == CURLUE_OUT_OF_MEMORY) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  if(portptr) {

    curl_off_t num;

    const char *p = portptr;

    if(!curlx_str_number(&p, &num, UINT16_MAX))

      pp.port = (uint16_t)num;

    /* Should we not error out when the port number is invalid? */

    curlx_free(portptr);

  }

  else {

    /* No port in URL, take the set one or the scheme's default */

    if(data->set.proxyport)

      pp.port = data->set.proxyport;

    else

      pp.port = pp.scheme->defport;

  }

  /* now, clone the proxy hostname */

  uc = curl_url_get(uh, CURLUPART_HOST, &pp.tmp_host_user, CURLU_URLDECODE);

  if(uc) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  pp.host_user.str = pp.tmp_host_user;

  pp.host_user.len = strlen(pp.tmp_host_user);

#ifdef USE_UNIX_SOCKETS

  if(is_socks && curl_strequal(UNIX_SOCKET_PREFIX, pp.tmp_host_user)) {

    uc = curl_url_get(uh, CURLUPART_PATH, &pp.tmp_host, CURLU_URLDECODE);

    if(uc) {

      result = CURLE_OUT_OF_MEMORY;

      goto out;

    }

    /* path will be "/", if no path was found */

    if(strcmp("/", pp.tmp_host)) {

      pp.host.str = pp.tmp_host;

      pp.host.len = strlen(pp.tmp_host);

      pp.unix_socket = TRUE;

    }

    else {

      pp.host = pp.host_user;

    }

  }

#endif /* USE_UNIX_SOCKETS */

  if(!pp.host.len) {

    result = peer_parse_host(data, &pp, FALSE);

    if(result)

      goto out;

  }

  uc = curl_url_get(uh, CURLUPART_ZONEID, &pp.tmp_zoneid, 0);

  if(uc == CURLUE_OUT_OF_MEMORY) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  if(pp.tmp_zoneid) {

    pp.zoneid.str = pp.tmp_zoneid;

    pp.zoneid.len = strlen(pp.tmp_zoneid);

  }

  *pproxytype = proxytype;

  result = peer_create(&pp, ppeer);

out:

  peer_parse_clear(&pp);

  curlx_free(scheme);

#ifdef DEBUGBUILD

  if(!result)

    DEBUGASSERT(*ppeer);

#endif

  return result;

}

#endif /* !CURL_DISABLE_PROXY */