/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010-2013 Andy Green * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation: * version 2.1 of the License. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301 USA */ #include "private-libwebsockets.h" #define LWS_CPYAPP(ptr, str) { strcpy(ptr, str); ptr += strlen(str); } #ifndef LWS_NO_EXTENSIONS static int lws_extension_server_handshake(struct lws *wsi, char **p, int budget) { struct lws_context *context = wsi->context; struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi]; char ext_name[64], *args, *end = (*p) + budget - 1; const struct lws_ext_options *opts, *po; const struct lws_extension *ext; struct lws_ext_option_arg oa; int n, m, more = 1; int ext_count = 0; char ignore; char *c; /* * Figure out which extensions the client has that we want to * enable on this connection, and give him back the list */ if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) return 0; /* * break down the list of client extensions * and go through them */ if (lws_hdr_copy(wsi, (char *)pt->serv_buf, context->pt_serv_buf_size, WSI_TOKEN_EXTENSIONS) < 0) return 1; c = (char *)pt->serv_buf; lwsl_parser("WSI_TOKEN_EXTENSIONS = '%s'\n", c); wsi->count_act_ext = 0; ignore = 0; n = 0; args = NULL; /* * We may get a simple request * * Sec-WebSocket-Extensions: permessage-deflate * * or an elaborated one with requested options * * Sec-WebSocket-Extensions: permessage-deflate; \ * server_no_context_takeover; \ * client_no_context_takeover */ while (more) { if (*c && (*c != ',' && *c != '\t')) { if (*c == ';') { ignore = 1; args = c + 1; } if (ignore || *c == ' ') { c++; continue; } ext_name[n] = *c++; if (n < sizeof(ext_name) - 1) n++; continue; } ext_name[n] = '\0'; ignore = 0; if (!*c) more = 0; else { c++; if (!n) continue; } while (args && *args && *args == ' ') args++; /* check a client's extension against our support */ ext = wsi->vhost->extensions; while (ext && ext->callback) { if (strcmp(ext_name, ext->name)) { ext++; continue; } /* * oh, we do support this one he asked for... but let's * confirm he only gave it once */ for (m = 0; m < wsi->count_act_ext; m++) if (wsi->active_extensions[m] == ext) { lwsl_info("extension mentioned twice\n"); return 1; /* shenanigans */ } /* * ask user code if it's OK to apply it on this * particular connection + protocol */ m = (wsi->protocol->callback)(wsi, LWS_CALLBACK_CONFIRM_EXTENSION_OKAY, wsi->user_space, 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 (m) { ext++; continue; } /* apply it */ ext_count++; /* instantiate the extension on this conn */ wsi->active_extensions[wsi->count_act_ext] = ext; /* allow him to construct his context */ if (ext->callback(lws_get_context(wsi), ext, wsi, LWS_EXT_CB_CONSTRUCT, (void *)&wsi->act_ext_user[ wsi->count_act_ext], (void *)&opts, 0)) { lwsl_info("ext %s failed construction\n", ext_name); ext_count--; ext++; continue; } if (ext_count > 1) *(*p)++ = ','; else LWS_CPYAPP(*p, "\x0d\x0aSec-WebSocket-Extensions: "); *p += lws_snprintf(*p, (end - *p), "%s", ext_name); /* * go through the options trying to apply the * recognized ones */ lwsl_debug("ext args %s", args); while (args && *args && *args != ',') { while (*args == ' ') args++; po = opts; while (po->name) { lwsl_debug("'%s' '%s'\n", po->name, args); /* only support arg-less options... */ if (po->type == EXTARG_NONE && !strncmp(args, po->name, strlen(po->name))) { oa.option_name = NULL; oa.option_index = po - opts; oa.start = NULL; lwsl_debug("setting %s\n", po->name); if (!ext->callback( lws_get_context(wsi), ext, wsi, LWS_EXT_CB_OPTION_SET, wsi->act_ext_user[ wsi->count_act_ext], &oa, (end - *p))) { *p += lws_snprintf(*p, (end - *p), "; %s", po->name); lwsl_debug("adding option %s\n", po->name); } } po++; } while (*args && *args != ',' && *args != ';') args++; } wsi->count_act_ext++; lwsl_parser("count_act_ext <- %d\n", wsi->count_act_ext); ext++; } n = 0; args = NULL; } return 0; } #endif int handshake_0405(struct lws_context *context, struct lws *wsi) { struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi]; struct lws_process_html_args args; unsigned char hash[20]; int n, accept_len; char *response; char *p; if (!lws_hdr_total_length(wsi, WSI_TOKEN_HOST) || !lws_hdr_total_length(wsi, WSI_TOKEN_KEY)) { lwsl_parser("handshake_04 missing pieces\n"); /* completed header processing, but missing some bits */ goto bail; } if (lws_hdr_total_length(wsi, WSI_TOKEN_KEY) >= MAX_WEBSOCKET_04_KEY_LEN) { lwsl_warn("Client key too long %d\n", MAX_WEBSOCKET_04_KEY_LEN); goto bail; } /* * since key length is restricted above (currently 128), cannot * overflow */ n = sprintf((char *)pt->serv_buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", lws_hdr_simple_ptr(wsi, WSI_TOKEN_KEY)); lws_SHA1(pt->serv_buf, n, hash); accept_len = lws_b64_encode_string((char *)hash, 20, (char *)pt->serv_buf, context->pt_serv_buf_size); if (accept_len < 0) { lwsl_warn("Base64 encoded hash too long\n"); goto bail; } /* allocate the per-connection user memory (if any) */ if (lws_ensure_user_space(wsi)) goto bail; /* create the response packet */ /* make a buffer big enough for everything */ response = (char *)pt->serv_buf + MAX_WEBSOCKET_04_KEY_LEN + LWS_PRE; p = response; LWS_CPYAPP(p, "HTTP/1.1 101 Switching Protocols\x0d\x0a" "Upgrade: WebSocket\x0d\x0a" "Connection: Upgrade\x0d\x0a" "Sec-WebSocket-Accept: "); strcpy(p, (char *)pt->serv_buf); p += accept_len; /* we can only return the protocol header if: * - one came in, and ... */ if (lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL) && /* - it is not an empty string */ wsi->protocol->name && wsi->protocol->name[0]) { LWS_CPYAPP(p, "\x0d\x0aSec-WebSocket-Protocol: "); p += lws_snprintf(p, 128, "%s", wsi->protocol->name); } #ifndef LWS_NO_EXTENSIONS /* * Figure out which extensions the client has that we want to * enable on this connection, and give him back the list. * * Give him a limited write bugdet */ if (lws_extension_server_handshake(wsi, &p, 192)) goto bail; #endif LWS_CPYAPP(p, "\x0d\x0a"); args.p = p; args.max_len = ((char *)pt->serv_buf + context->pt_serv_buf_size) - p; if (user_callback_handle_rxflow(wsi->protocol->callback, wsi, LWS_CALLBACK_ADD_HEADERS, wsi->user_space, &args, 0)) goto bail; p = args.p; /* end of response packet */ LWS_CPYAPP(p, "\x0d\x0a"); if (!lws_any_extension_handled(wsi, LWS_EXT_CB_HANDSHAKE_REPLY_TX, response, p - response)) { /* okay send the handshake response accepting the connection */ lwsl_parser("issuing resp pkt %d len\n", (int)(p - response)); #if defined(DEBUG) && ! defined(LWS_WITH_ESP8266) fwrite(response, 1, p - response, stderr); #endif n = lws_write(wsi, (unsigned char *)response, p - response, LWS_WRITE_HTTP_HEADERS); if (n != (p - response)) { lwsl_debug("handshake_0405: ERROR writing to socket\n"); goto bail; } } /* alright clean up and set ourselves into established state */ wsi->state = LWSS_ESTABLISHED; wsi->lws_rx_parse_state = LWS_RXPS_NEW; { const char * uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI); int uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI); const struct lws_http_mount *hit = lws_find_mount(wsi, uri_ptr, uri_len); if (hit && hit->cgienv && wsi->protocol->callback(wsi, LWS_CALLBACK_HTTP_PMO, wsi->user_space, (void *)hit->cgienv, 0)) return 1; } return 0; bail: /* caller will free up his parsing allocations */ return -1; }