/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010-2014 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" static int libwebsocket_0405_frame_mask_generate(struct libwebsocket *wsi) { int n; /* fetch the per-frame nonce */ n = libwebsockets_get_random(wsi->protocol->owning_server, wsi->u.ws.frame_masking_nonce_04, 4); if (n != 4) { lwsl_parser("Unable to read from random device %s %d\n", SYSTEM_RANDOM_FILEPATH, n); return 1; } /* start masking from first byte of masking key buffer */ wsi->u.ws.frame_mask_index = 0; return 0; } #ifdef _DEBUG LWS_VISIBLE void lwsl_hexdump(void *vbuf, size_t len) { int n; int m; int start; unsigned char *buf = (unsigned char *)vbuf; char line[80]; char *p; lwsl_parser("\n"); for (n = 0; n < len;) { start = n; p = line; p += sprintf(p, "%04X: ", start); for (m = 0; m < 16 && n < len; m++) p += sprintf(p, "%02X ", buf[n++]); while (m++ < 16) p += sprintf(p, " "); p += sprintf(p, " "); for (m = 0; m < 16 && (start + m) < len; m++) { if (buf[start + m] >= ' ' && buf[start + m] < 127) *p++ = buf[start + m]; else *p++ = '.'; } while (m++ < 16) *p++ = ' '; *p++ = '\n'; *p = '\0'; lwsl_debug("%s", line); } lwsl_debug("\n"); } #endif /* * notice this returns number of bytes consumed, or -1 */ int lws_issue_raw(struct libwebsocket *wsi, unsigned char *buf, size_t len) { struct libwebsocket_context *context = wsi->protocol->owning_server; int n; size_t real_len = len; int m; if (!len) return 0; /* just ignore sends after we cleared the truncation buffer */ if (wsi->state == WSI_STATE_FLUSHING_STORED_SEND_BEFORE_CLOSE && !wsi->truncated_send_len) return len; if (wsi->truncated_send_len && (buf < wsi->truncated_send_malloc || buf > (wsi->truncated_send_malloc + wsi->truncated_send_len + wsi->truncated_send_offset))) { lwsl_err("****** %x Sending new, pending truncated ...\n", wsi); assert(0); } m = lws_ext_callback_for_each_active(wsi, LWS_EXT_CALLBACK_PACKET_TX_DO_SEND, &buf, len); if (m < 0) return -1; if (m) /* handled */ { n = m; goto handle_truncated_send; } if (wsi->sock < 0) lwsl_warn("** error invalid sock but expected to send\n"); /* * nope, send it on the socket directly */ lws_latency_pre(context, wsi); n = lws_ssl_capable_write(wsi, buf, len); lws_latency(context, wsi, "send lws_issue_raw", n, n == len); switch (n) { case LWS_SSL_CAPABLE_ERROR: return -1; case LWS_SSL_CAPABLE_MORE_SERVICE: /* nothing got sent, not fatal, retry the whole thing later */ n = 0; break; } handle_truncated_send: /* * we were already handling a truncated send? */ if (wsi->truncated_send_len) { lwsl_info("***** %x partial send moved on by %d (vs %d)\n", wsi, n, real_len); wsi->truncated_send_offset += n; wsi->truncated_send_len -= n; if (!wsi->truncated_send_len) { lwsl_info("***** %x partial send completed\n", wsi); /* done with it, but don't free it */ n = real_len; if (wsi->state == WSI_STATE_FLUSHING_STORED_SEND_BEFORE_CLOSE) { lwsl_info("***** %x signalling to close now\n", wsi); return -1; /* retry closing now */ } } /* always callback on writeable */ libwebsocket_callback_on_writable( wsi->protocol->owning_server, wsi); return n; } if (n == real_len) /* what we just sent went out cleanly */ return n; if (n && wsi->u.ws.clean_buffer) /* * This buffer unaffected by extension rewriting. * It means the user code is expected to deal with * partial sends. (lws knows the header was already * sent, so on next send will just resume sending * payload) */ return n; /* * Newly truncated send. Buffer the remainder (it will get * first priority next time the socket is writable) */ lwsl_info("***** %x new partial sent %d from %d total\n", wsi, n, real_len); /* * - if we still have a suitable malloc lying around, use it * - or, if too small, reallocate it * - or, if no buffer, create it */ if (!wsi->truncated_send_malloc || real_len - n > wsi->truncated_send_allocation) { if (wsi->truncated_send_malloc) free(wsi->truncated_send_malloc); wsi->truncated_send_allocation = real_len - n; wsi->truncated_send_malloc = malloc(real_len - n); if (!wsi->truncated_send_malloc) { lwsl_err("truncated send: unable to malloc %d\n", real_len - n); return -1; } } wsi->truncated_send_offset = 0; wsi->truncated_send_len = real_len - n; memcpy(wsi->truncated_send_malloc, buf + n, real_len - n); /* since something buffered, force it to get another chance to send */ libwebsocket_callback_on_writable(wsi->protocol->owning_server, wsi); return real_len; } /** * libwebsocket_write() - Apply protocol then write data to client * @wsi: Websocket instance (available from user callback) * @buf: The data to send. For data being sent on a websocket * connection (ie, not default http), this buffer MUST have * LWS_SEND_BUFFER_PRE_PADDING bytes valid BEFORE the pointer * and an additional LWS_SEND_BUFFER_POST_PADDING bytes valid * in the buffer after (buf + len). This is so the protocol * header and trailer data can be added in-situ. * @len: Count of the data bytes in the payload starting from buf * @protocol: Use LWS_WRITE_HTTP to reply to an http connection, and one * of LWS_WRITE_BINARY or LWS_WRITE_TEXT to send appropriate * data on a websockets connection. Remember to allow the extra * bytes before and after buf if LWS_WRITE_BINARY or LWS_WRITE_TEXT * are used. * * This function provides the way to issue data back to the client * for both http and websocket protocols. * * In the case of sending using websocket protocol, be sure to allocate * valid storage before and after buf as explained above. This scheme * allows maximum efficiency of sending data and protocol in a single * packet while not burdening the user code with any protocol knowledge. * * Return may be -1 for a fatal error needing connection close, or a * positive number reflecting the amount of bytes actually sent. This * can be less than the requested number of bytes due to OS memory * pressure at any given time. */ LWS_VISIBLE int libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf, size_t len, enum libwebsocket_write_protocol protocol) { int n; int pre = 0; int post = 0; int masked7 = wsi->mode == LWS_CONNMODE_WS_CLIENT; unsigned char *dropmask = NULL; unsigned char is_masked_bit = 0; size_t orig_len = len; struct lws_tokens eff_buf; if (len == 0 && protocol != LWS_WRITE_CLOSE && protocol != LWS_WRITE_PING && protocol != LWS_WRITE_PONG) { lwsl_warn("zero length libwebsocket_write attempt\n"); return 0; } if (protocol == LWS_WRITE_HTTP) goto send_raw; /* websocket protocol, either binary or text */ if (wsi->state != WSI_STATE_ESTABLISHED) return -1; /* if we are continuing a frame that already had its header done */ if (wsi->u.ws.inside_frame) goto do_more_inside_frame; /* if he wants all partials buffered, never have a clean_buffer */ wsi->u.ws.clean_buffer = !wsi->protocol->no_buffer_all_partial_tx; /* * give a chance to the extensions to modify payload * pre-TX mangling is not allowed to truncate */ eff_buf.token = (char *)buf; eff_buf.token_len = len; switch (protocol) { case LWS_WRITE_PING: case LWS_WRITE_PONG: case LWS_WRITE_CLOSE: break; default: if (lws_ext_callback_for_each_active(wsi, LWS_EXT_CALLBACK_PAYLOAD_TX, &eff_buf, 0) < 0) return -1; } /* * an extension did something we need to keep... for example, if * compression extension, it has already updated its state according * to this being issued */ if ((char *)buf != eff_buf.token) /* * extension recreated it: * need to buffer this if not all sent */ wsi->u.ws.clean_buffer = 0; buf = (unsigned char *)eff_buf.token; len = eff_buf.token_len; switch (wsi->ietf_spec_revision) { case 13: if (masked7) { pre += 4; dropmask = &buf[0 - pre]; is_masked_bit = 0x80; } switch (protocol & 0xf) { case LWS_WRITE_TEXT: n = LWS_WS_OPCODE_07__TEXT_FRAME; break; case LWS_WRITE_BINARY: n = LWS_WS_OPCODE_07__BINARY_FRAME; break; case LWS_WRITE_CONTINUATION: n = LWS_WS_OPCODE_07__CONTINUATION; break; case LWS_WRITE_CLOSE: n = LWS_WS_OPCODE_07__CLOSE; /* * 06+ has a 2-byte status code in network order * we can do this because we demand post-buf */ if (wsi->u.ws.close_reason) { /* reason codes count as data bytes */ buf -= 2; buf[0] = wsi->u.ws.close_reason >> 8; buf[1] = wsi->u.ws.close_reason; len += 2; } break; case LWS_WRITE_PING: n = LWS_WS_OPCODE_07__PING; break; case LWS_WRITE_PONG: n = LWS_WS_OPCODE_07__PONG; break; default: lwsl_warn("lws_write: unknown write opc / protocol\n"); return -1; } if (!(protocol & LWS_WRITE_NO_FIN)) n |= 1 << 7; if (len < 126) { pre += 2; buf[-pre] = n; buf[-pre + 1] = len | is_masked_bit; } else { if (len < 65536) { pre += 4; buf[-pre] = n; buf[-pre + 1] = 126 | is_masked_bit; buf[-pre + 2] = len >> 8; buf[-pre + 3] = len; } else { pre += 10; buf[-pre] = n; buf[-pre + 1] = 127 | is_masked_bit; #if defined __LP64__ buf[-pre + 2] = (len >> 56) & 0x7f; buf[-pre + 3] = len >> 48; buf[-pre + 4] = len >> 40; buf[-pre + 5] = len >> 32; #else buf[-pre + 2] = 0; buf[-pre + 3] = 0; buf[-pre + 4] = 0; buf[-pre + 5] = 0; #endif buf[-pre + 6] = len >> 24; buf[-pre + 7] = len >> 16; buf[-pre + 8] = len >> 8; buf[-pre + 9] = len; } } break; } do_more_inside_frame: /* * Deal with masking if we are in client -> server direction and * the protocol demands it */ if (wsi->mode == LWS_CONNMODE_WS_CLIENT) { if (!wsi->u.ws.inside_frame) if (libwebsocket_0405_frame_mask_generate(wsi)) { lwsl_err("frame mask generation failed\n"); return -1; } /* * in v7, just mask the payload */ if (dropmask) { /* never set if already inside frame */ for (n = 4; n < (int)len + 4; n++) dropmask[n] = dropmask[n] ^ wsi->u.ws.frame_masking_nonce_04[ (wsi->u.ws.frame_mask_index++) & 3]; /* copy the frame nonce into place */ memcpy(dropmask, wsi->u.ws.frame_masking_nonce_04, 4); } } send_raw: switch (protocol) { case LWS_WRITE_CLOSE: /* lwsl_hexdump(&buf[-pre], len + post); */ case LWS_WRITE_HTTP: case LWS_WRITE_PONG: case LWS_WRITE_PING: return lws_issue_raw(wsi, (unsigned char *)buf - pre, len + pre + post); default: break; } wsi->u.ws.inside_frame = 1; /* * give any active extensions a chance to munge the buffer * before send. We pass in a pointer to an lws_tokens struct * prepared with the default buffer and content length that's in * there. Rather than rewrite the default buffer, extensions * that expect to grow the buffer can adapt .token to * point to their own per-connection buffer in the extension * user allocation. By default with no extensions or no * extension callback handling, just the normal input buffer is * used then so it is efficient. * * callback returns 1 in case it wants to spill more buffers * * This takes care of holding the buffer if send is incomplete, ie, * if wsi->u.ws.clean_buffer is 0 (meaning an extension meddled with * the buffer). If wsi->u.ws.clean_buffer is 1, it will instead * return to the user code how much OF THE USER BUFFER was consumed. */ n = lws_issue_raw_ext_access(wsi, buf - pre, len + pre + post); if (n <= 0) return n; if (n == len + pre + post) { /* everything in the buffer was handled (or rebuffered...) */ wsi->u.ws.inside_frame = 0; return orig_len; } /* * it is how many bytes of user buffer got sent... may be < orig_len * in which case callback when writable has already been arranged * and user code can call libwebsocket_write() again with the rest * later. */ return n - (pre + post); } LWS_VISIBLE int libwebsockets_serve_http_file_fragment( struct libwebsocket_context *context, struct libwebsocket *wsi) { int n; int m; while (!lws_send_pipe_choked(wsi)) { if (wsi->truncated_send_len) { if (lws_issue_raw(wsi, wsi->truncated_send_malloc + wsi->truncated_send_offset, wsi->truncated_send_len) < 0) { lwsl_info("closing from libwebsockets_serve_http_file_fragment\n"); return -1; } continue; } if (wsi->u.http.filepos == wsi->u.http.filelen) goto all_sent; compatible_file_read(n, wsi->u.http.fd, context->service_buffer, sizeof(context->service_buffer)); if (n < 0) return -1; /* caller will close */ if (n) { m = libwebsocket_write(wsi, context->service_buffer, n, LWS_WRITE_HTTP); if (m < 0) return -1; wsi->u.http.filepos += m; if (m != n) /* adjust for what was not sent */ compatible_file_seek_cur(wsi->u.http.fd, m - n); } all_sent: if (!wsi->truncated_send_len && wsi->u.http.filepos == wsi->u.http.filelen) { wsi->state = WSI_STATE_HTTP; if (wsi->protocol->callback) /* ignore callback returned value */ user_callback_handle_rxflow( wsi->protocol->callback, context, wsi, LWS_CALLBACK_HTTP_FILE_COMPLETION, wsi->user_space, NULL, 0); return 1; /* >0 indicates completed */ } } lwsl_info("choked before able to send whole file (post)\n"); libwebsocket_callback_on_writable(context, wsi); return 0; /* indicates further processing must be done */ } LWS_VISIBLE int lws_ssl_capable_read_no_ssl(struct libwebsocket *wsi, unsigned char *buf, int len) { int n; n = recv(wsi->sock, buf, len, 0); if (n >= 0) return n; lwsl_warn("error on reading from skt\n"); return LWS_SSL_CAPABLE_ERROR; } LWS_VISIBLE int lws_ssl_capable_write_no_ssl(struct libwebsocket *wsi, unsigned char *buf, int len) { int n; n = send(wsi->sock, buf, len, 0); if (n >= 0) return n; if (LWS_ERRNO == LWS_EAGAIN || LWS_ERRNO == LWS_EWOULDBLOCK || LWS_ERRNO == LWS_EINTR) { if (LWS_ERRNO == LWS_EWOULDBLOCK) lws_set_blocking_send(wsi); return LWS_SSL_CAPABLE_MORE_SERVICE; } lwsl_debug("ERROR writing len %d to skt %d\n", len, n); return LWS_SSL_CAPABLE_ERROR; }