/*

 * libwebsockets - small server side websockets and web server implementation

 *

 * Copyright (C) 2010 - 2021 Andy Green <andy@warmcat.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include <private-lib-core.h>

/*

 * In-place str to lower case

 */

static void

strtolower(char *s)

{

  while (*s) {

#ifdef LWS_PLAT_OPTEE

    int tolower_optee(int c);

    *s = tolower_optee((int)*s);

#else

    *s = (char)tolower((int)*s);

#endif

    s++;

  }

}

int

lws_create_client_ws_object(const struct lws_client_connect_info *i,

          struct lws *wsi)

{

  int v = SPEC_LATEST_SUPPORTED;

  /* allocate the ws struct for the wsi */

  wsi->ws = lws_zalloc(sizeof(*wsi->ws), "client ws struct");

  if (!wsi->ws) {

    lwsl_wsi_notice(wsi, "OOM");

    return 1;

  }

  /* -1 means just use latest supported */

  if (i->ietf_version_or_minus_one != -1 &&

      i->ietf_version_or_minus_one)

    v = i->ietf_version_or_minus_one;

  wsi->ws->ietf_spec_revision = (uint8_t)v;

  if (i->allow_reserved_bits)

    wsi->ws->allow_reserved_bits = 1;

  if (i->allow_unknown_opcode)

    wsi->ws->allow_unknown_opcode = 1;

  return 0;

}

#if defined(LWS_WITH_CLIENT)

/*

 * Returns either LWS_HPI_RET_PLEASE_CLOSE_ME or LWS_HPI_RET_HANDLED

 */

lws_handling_result_t

lws_ws_handshake_client(struct lws *wsi, unsigned char **buf, size_t len)

{

  const uint8_t **cbuf = (const uint8_t **)buf;

  unsigned char *start_buf = *buf;

  if ((lwsi_state(wsi) != LRS_WAITING_PROXY_REPLY) &&

      (lwsi_state(wsi) != LRS_H1C_ISSUE_HANDSHAKE) &&

      (lwsi_state(wsi) != LRS_WAITING_SERVER_REPLY) &&

      !lwsi_role_client(wsi))

    return LWS_HPI_RET_HANDLED;

  lwsl_wsi_debug(wsi, "hs client has %d in", (int)len);

  if (lws_is_flowcontrolled(wsi)) {

    lwsl_wsi_debug(wsi, "caching %ld", (long)len);

    if (lws_rxflow_cache(wsi, *buf, 0, len) == LWSRXFC_TRIMMED) {

      lwsl_wsi_info(wsi, "trimming inside rxflow cache");

      /* we indicate we used nothing, caller will not advance */

    } else {

      *buf += len; /* we indicate we used it all */

    }

    return LWS_HPI_RET_HANDLED;

  }

#if !defined(LWS_WITHOUT_EXTENSIONS)

  if (wsi->ws->rx_draining_ext) {

    lwsl_wsi_info(wsi, "draining ext");

    if (lws_ws_client_rx_sm(wsi, 0) == LWS_HPI_RET_PLEASE_CLOSE_ME)

      return LWS_HPI_RET_PLEASE_CLOSE_ME;

  }

#endif

  if (len) {

    if (lws_ws_client_rx_parser_block(wsi, cbuf, &len) !=

              LWS_HPI_RET_HANDLED) {

      lwsl_wsi_info(wsi, "client_rx_parser exited, closing");

      *buf = start_buf + len; /* Update how much we used */

      return LWS_HPI_RET_PLEASE_CLOSE_ME;

    }

  }

  return LWS_HPI_RET_HANDLED;

}

#endif

char *

lws_generate_client_ws_handshake(struct lws *wsi, char *p, const char *conn1, size_t p_len)

{

  char buf[128], hash[20], key_b64[40], *end = p + p_len;

  size_t s;

#if !defined(LWS_WITHOUT_EXTENSIONS)

  const struct lws_extension *ext;

  int ext_count = 0;

#endif

  /*

   * create the random key

   */

  if (lws_get_random(wsi->a.context, hash, 16) != 16) {

    lwsl_wsi_err(wsi, "Unable to read from random dev %s",

       SYSTEM_RANDOM_FILEPATH);

    return NULL;

  }

  /* coverity[tainted_scalar] */

  lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));

  p += lws_snprintf(p, lws_ptr_diff_size_t(end, p),

        "Upgrade: websocket\x0d\x0a"

        "Connection: %sUpgrade\x0d\x0a"

        "Sec-WebSocket-Key: ", conn1);

  if (lws_ptr_diff_size_t(end, p) < strlen(key_b64) + 2 + 128)

    return NULL;

  lws_strncpy(p, key_b64, lws_ptr_diff_size_t(end, p));

  p += strlen(key_b64);

  p += lws_snprintf(p, lws_ptr_diff_size_t(end, p), "\x0d\x0a");

  if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))

    p += lws_snprintf(p, lws_ptr_diff_size_t(end, p),

          "Sec-WebSocket-Protocol: %s\x0d\x0a",

         lws_hdr_simple_ptr(wsi,

             _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));

  /* tell the server what extensions we could support */

#if !defined(LWS_WITHOUT_EXTENSIONS)

  ext = wsi->a.vhost->ws.extensions;

  while (ext && ext->callback) {

    int n = wsi->a.vhost->protocols[0].callback(wsi,

      LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,

        wsi->user_space, (char *)ext->name, 0);

    /*

     * zero return from callback means go ahead and allow

     * the extension, it's what we get if the callback is

     * unhandled

     */

    if (n) {

      ext++;

      continue;

    }

    /* apply it */

    if (ext_count)

      *p++ = ',';

    else

      p += lws_snprintf(p, lws_ptr_diff_size_t(end, p),

            "Sec-WebSocket-Extensions: ");

    p += lws_snprintf(p, lws_ptr_diff_size_t(end, p),

          "%s", ext->client_offer);

    ext_count++;

    ext++;

  }

  if (ext_count)

    p += lws_snprintf(p, lws_ptr_diff_size_t(end, p), "\x0d\x0a");

#endif

  if (wsi->ws->ietf_spec_revision)

    p += lws_snprintf(p, lws_ptr_diff_size_t(end, p),

          "Sec-WebSocket-Version: %d\x0d\x0a",

          wsi->ws->ietf_spec_revision);

  /* prepare the expected server accept response */

  key_b64[39] = '\0'; /* enforce composed length below buf sizeof */

  s = strlen(key_b64);

  memcpy(buf, key_b64, s);

  memcpy(buf + s, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11", 36);

  s += 36;

  lws_SHA1((unsigned char *)buf, (unsigned int)s, (unsigned char *)hash);

  lws_b64_encode_string(hash, 20,

      wsi->http.ah->initial_handshake_hash_base64,

      sizeof(wsi->http.ah->initial_handshake_hash_base64));

  return p;

}

int

lws_client_ws_upgrade(struct lws *wsi, const char **cce)

{

  struct lws_context *context = wsi->a.context;

  struct lws_tokenize ts;

  int n, len, okay = 0;

  lws_tokenize_elem e;

  char *p, buf[64];

  const char *pc;

#if !defined(LWS_WITHOUT_EXTENSIONS)

  struct lws_context_per_thread *pt = &wsi->a.context->pt[(int)wsi->tsi];

  char *sb = (char *)&pt->serv_buf[0];

  const struct lws_ext_options *opts;

  const struct lws_extension *ext;

  char ext_name[128];

  const char *c, *a;

  int more = 1;

  char ignore;

#endif

  if (wsi->client_mux_substream) {/* !!! client ws-over-h2 not there yet */

    lwsl_wsi_warn(wsi, "client ws-over-h2 upgrade not supported yet");

    *cce = "HS: h2 / ws upgrade unsupported";

    goto bail3;

  }

  if (wsi->http.ah->http_response == 401) {

    lwsl_wsi_warn(wsi, "got bad HTTP response '%ld'",

            (long)wsi->http.ah->http_response);

    *cce = "HS: ws upgrade unauthorized";

    goto bail3;

  }

  if (wsi->http.ah->http_response != 101) {

    lwsl_wsi_warn(wsi, "got bad HTTP response '%ld'",

            (long)wsi->http.ah->http_response);

    *cce = "HS: ws upgrade response not 101";

    goto bail3;

  }

  if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {

    lwsl_wsi_info(wsi, "no ACCEPT");

    *cce = "HS: ACCEPT missing";

    goto bail3;

  }

  p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);

  if (!p) {

    lwsl_wsi_info(wsi, "no UPGRADE");

    *cce = "HS: UPGRADE missing";

    goto bail3;

  }

  strtolower(p);

  if (strcmp(p, "websocket")) {

    lwsl_wsi_warn(wsi, "got bad Upgrade header '%s'", p);

    *cce = "HS: Upgrade to something other than websocket";

    goto bail3;

  }

  /* connection: must have "upgrade" */

  lws_tokenize_init(&ts, buf, LWS_TOKENIZE_F_COMMA_SEP_LIST |

            LWS_TOKENIZE_F_MINUS_NONTERM);

  n = lws_hdr_copy(wsi, buf, sizeof(buf) - 1, WSI_TOKEN_CONNECTION);

  if (n <= 0) /* won't fit, or absent */

    goto bad_conn_format;

  ts.len = (unsigned int)n;

  do {

    e = lws_tokenize(&ts);

    switch (e) {

    case LWS_TOKZE_TOKEN:

      if (!strncasecmp(ts.token, "upgrade", ts.token_len))

        e = LWS_TOKZE_ENDED;

      break;

    case LWS_TOKZE_DELIMITER:

      break;

    default: /* includes ENDED found by the tokenizer itself */

bad_conn_format:

      lwsl_wsi_info(wsi, "malformed connection '%s'", buf);

      *cce = "HS: UPGRADE malformed";

      goto bail3;

    }

  } while (e > 0);

  pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);

#if defined(_DEBUG)

  if (!pc)

    lwsl_wsi_parser(wsi, "lws_client_int_s_hs: no protocol list");

  else

    lwsl_wsi_parser(wsi, "lws_client_int_s_hs: protocol list '%s'", pc);

#endif

  /*

   * confirm the protocol the server wants to talk was in the list

   * of protocols we offered

   */

  len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);

  if (!len) {

    lwsl_wsi_info(wsi, "WSI_TOKEN_PROTOCOL is null");

    /*

     * no protocol name to work from, if we don't already have one

     * default to first protocol

     */

    if (wsi->a.protocol) {

      p = (char *)wsi->a.protocol->name;

      goto identify_protocol;

    }

    /* no choice but to use the default protocol */

    n = 0;

    wsi->a.protocol = &wsi->a.vhost->protocols[0];

    goto check_extensions;

  }

  p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);

  len = (int)strlen(p);

  while (pc && *pc && !okay) {

    if (!strncmp(pc, p, (unsigned int)len) &&

        (pc[len] == ',' || pc[len] == '\0')) {

      okay = 1;

      continue;

    }

    while (*pc && *pc++ != ',')

      ;

    while (*pc == ' ')

      pc++;

  }

  if (!okay) {

    lwsl_wsi_info(wsi, "got bad protocol %s", p);

    *cce = "HS: PROTOCOL malformed";

    goto bail2;

  }

identify_protocol:

#if defined(LWS_WITH_HTTP_PROXY)

  lws_strncpy(wsi->ws->actual_protocol, p,

        sizeof(wsi->ws->actual_protocol));

#endif

  /*

   * identify the selected protocol struct and set it

   */

  n = 0;

  /* keep client connection pre-bound protocol */

  if (!lwsi_role_client(wsi))

    wsi->a.protocol = NULL;

  while (n < wsi->a.vhost->count_protocols) {

    if (!wsi->a.protocol &&

        strcmp(p, wsi->a.vhost->protocols[n].name) == 0) {

      wsi->a.protocol = &wsi->a.vhost->protocols[n];

      break;

    }

    n++;

  }

  if (n == wsi->a.vhost->count_protocols) { /* no match */

    /* if server, that's already fatal */

    if (!lwsi_role_client(wsi)) {

      lwsl_wsi_info(wsi, "fail protocol %s", p);

      *cce = "HS: Cannot match protocol";

      goto bail2;

    }

    /* for client, find the index of our pre-bound protocol */

    n = 0;

    while (wsi->a.vhost->protocols[n].callback) {

      if (wsi->a.protocol && strcmp(wsi->a.protocol->name,

           wsi->a.vhost->protocols[n].name) == 0) {

        wsi->a.protocol = &wsi->a.vhost->protocols[n];

        break;

      }

      n++;

    }

    if (!wsi->a.vhost->protocols[n].callback) {

      if (wsi->a.protocol)

        lwsl_wsi_err(wsi, "Failed to match protocol %s",

            wsi->a.protocol->name);

      else

        lwsl_wsi_err(wsi, "No protocol on client");

      *cce = "ws protocol no match";

      goto bail2;

    }

  }

  lwsl_wsi_debug(wsi, "Selected protocol %s", wsi->a.protocol ?

               wsi->a.protocol->name : "no pcol");

check_extensions:

  /*

   * stitch protocol choice into the vh protocol linked list

   * We always insert ourselves at the start of the list

   *

   * X <-> B

   * X <-> pAn <-> pB

   */

  lws_same_vh_protocol_insert(wsi, n);

#if !defined(LWS_WITHOUT_EXTENSIONS)

  /* instantiate the accepted extensions */

  if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {

    lwsl_wsi_ext(wsi, "no client extensions allowed by server");

    goto check_accept;

  }

  /*

   * break down the list of server accepted extensions

   * and go through matching them or identifying bogons

   */

  if (lws_hdr_copy(wsi, sb, (int)context->pt_serv_buf_size,

       WSI_TOKEN_EXTENSIONS) < 0) {

    lwsl_wsi_warn(wsi, "ext list from server failed to copy");

    *cce = "HS: EXT: list too big";

    goto bail2;

  }

  c = sb;

  n = 0;

  ignore = 0;

  a = NULL;

  while (more) {

    if (*c && (*c != ',' && *c != '\t')) {

      if (*c == ';') {

        ignore = 1;

        if (!a)

          a = c + 1;

      }

      if (ignore || *c == ' ') {

        c++;

        continue;

      }

      ext_name[n] = *c++;

      if (n < (int)sizeof(ext_name) - 1)

        n++;

      continue;

    }

    ext_name[n] = '\0';

    ignore = 0;

    if (!*c)

      more = 0;

    else {

      c++;

      if (!n)

        continue;

    }

    /* check we actually support it */

    lwsl_wsi_notice(wsi, "checking client ext %s", ext_name);

    n = 0;

    ext = wsi->a.vhost->ws.extensions;

    while (ext && ext->callback) {

      if (strcmp(ext_name, ext->name)) {

        ext++;

        continue;

      }

      n = 1;

      lwsl_wsi_notice(wsi, "instantiating client ext %s", ext_name);

      /* instantiate the extension on this conn */

      wsi->ws->active_extensions[wsi->ws->count_act_ext] = ext;

      /* allow him to construct his ext instance */

      if (ext->callback(lws_get_context(wsi), ext, wsi,

           LWS_EXT_CB_CLIENT_CONSTRUCT,

           (void *)&wsi->ws->act_ext_user[

                                wsi->ws->count_act_ext],

           (void *)&opts, 0)) {

        lwsl_wsi_info(wsi, " ext %s failed construction",

            ext_name);

        ext++;

        continue;

      }

      /*

       * allow the user code to override ext defaults if it

       * wants to

       */

      ext_name[0] = '\0';

      if (user_callback_handle_rxflow(wsi->a.protocol->callback,

          wsi, LWS_CALLBACK_WS_EXT_DEFAULTS,

          (char *)ext->name, ext_name,

          sizeof(ext_name))) {

        *cce = "HS: EXT: failed setting defaults";

        goto bail2;

      }

      if (ext_name[0] &&

          lws_ext_parse_options(ext, wsi,

                    wsi->ws->act_ext_user[

                    wsi->ws->count_act_ext],

                    opts, ext_name,

              (int)strlen(ext_name))) {

        lwsl_wsi_err(wsi, "unable to parse user defaults '%s'",

               ext_name);

        *cce = "HS: EXT: failed parsing defaults";

        goto bail2;

      }

      /*

       * give the extension the server options

       */

      if (a && lws_ext_parse_options(ext, wsi,

          wsi->ws->act_ext_user[

                          wsi->ws->count_act_ext],

          opts, a, lws_ptr_diff(c, a))) {

        lwsl_wsi_err(wsi, "unable to parse remote def '%s'", a);

        *cce = "HS: EXT: failed parsing options";

        goto bail2;

      }

      if (ext->callback(lws_get_context(wsi), ext, wsi,

          LWS_EXT_CB_OPTION_CONFIRM,

              wsi->ws->act_ext_user[wsi->ws->count_act_ext],

              NULL, 0)) {

        lwsl_wsi_err(wsi, "ext %s rejects server options %s",

               ext->name, a);

        *cce = "HS: EXT: Rejects server options";

        goto bail2;

      }

      wsi->ws->count_act_ext++;

      ext++;

    }

    if (n == 0) {

      lwsl_wsi_warn(wsi, "Unknown ext '%s'!", ext_name);

      *cce = "HS: EXT: unknown ext";

      goto bail2;

    }

    a = NULL;

    n = 0;

  }

check_accept:

#endif

  /*

   * Confirm his accept token is the one we precomputed

   */

  p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);

  if (strcmp(p, wsi->http.ah->initial_handshake_hash_base64)) {

    lwsl_wsi_warn(wsi, "lws_client_int_s_hs: accept '%s' wrong vs '%s'", p,

          wsi->http.ah->initial_handshake_hash_base64);

    *cce = "HS: Accept hash wrong";

    goto bail2;

  }

  /* allocate the per-connection user memory (if any) */

  if (lws_ensure_user_space(wsi)) {

    lwsl_wsi_err(wsi, "Problem allocating wsi user mem");

    *cce = "HS: OOM";

    goto bail2;

  }

  /*

   * we seem to be good to go, give client last chance to check

   * headers and OK it

   */

  if (wsi->a.protocol->callback(wsi,

            LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,

            wsi->user_space, NULL, 0)) {

    *cce = "HS: Rejected by filter cb";

    goto bail2;

  }

  /* clear his proxy connection timeout */

  lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);

  /* free up his parsing allocations */

  lws_header_table_detach(wsi, 0);

  lws_role_transition(wsi, LWSIFR_CLIENT, LRS_ESTABLISHED, &role_ops_ws);

  lws_validity_confirmed(wsi);

  wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;

  /*

   * create the frame buffer for this connection according to the

   * size mentioned in the protocol definition.  If 0 there, then

   * use a big default for compatibility

   */

  n = (int)wsi->a.protocol->rx_buffer_size;

  if (!n)

    n = (int)context->pt_serv_buf_size;

  n += LWS_PRE;

  wsi->ws->rx_ubuf = lws_malloc((unsigned int)n + 4 /* 0x0000ffff zlib */,

        "client frame buffer");

  if (!wsi->ws->rx_ubuf) {

    lwsl_wsi_err(wsi, "OOM allocating rx buffer %d", n);

    *cce = "HS: OOM";

    goto bail2;

  }

  wsi->ws->rx_ubuf_alloc = (unsigned int)n;

  lwsl_wsi_debug(wsi, "handshake OK for protocol %s", wsi->a.protocol->name);

  /* call him back to inform him he is up */

  if (wsi->a.protocol->callback(wsi, LWS_CALLBACK_CLIENT_ESTABLISHED,

            wsi->user_space, NULL, 0)) {

    *cce = "HS: Rejected at CLIENT_ESTABLISHED";

    goto bail3;

  }

  return 0;

bail3:

  return 3;

bail2:

  return 2;

}