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vnc: added initial websocket protocol support
This patch adds basic Websocket Protocol version 13 - RFC 6455 - support to QEMU VNC. Binary encoding support on the client side is mandatory. Because of the GnuTLS requirement the Websockets implementation is optional (--enable-vnc-ws). To activate Websocket support the VNC option "websocket"is used, for example "-vnc :0,websocket". The listen port for Websocket connections is (5700 + display) so if QEMU VNC is started with :0 the Websocket port would be 5700. As an alternative the Websocket port could be manually specified by using ",websocket=<port>" instead. Parts of the implementation base on Anthony Liguori's QEMU Websocket patch from 2010 and on Joel Martin's LibVNC Websocket implementation. Signed-off-by: Tim Hardeck <thardeck@suse.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,284 @@ | ||
| /* | ||
| * QEMU VNC display driver: Websockets support | ||
| * | ||
| * Copyright (C) 2010 Joel Martin | ||
| * Copyright (C) 2012 Tim Hardeck | ||
| * | ||
| * This is free software; you can redistribute it and/or modify | ||
| * it under the terms of the GNU General Public License as published by | ||
| * the Free Software Foundation; either version 2 of the License, or | ||
| * (at your option) any later version. | ||
| * | ||
| * This software 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 General Public License for more details. | ||
| * | ||
| * You should have received a copy of the GNU General Public License | ||
| * along with this software; if not, see <http://www.gnu.org/licenses/>. | ||
| */ | ||
|
|
||
| #include "vnc.h" | ||
|
|
||
| void vncws_handshake_read(void *opaque) | ||
| { | ||
| VncState *vs = opaque; | ||
| uint8_t *handshake_end; | ||
| long ret; | ||
| buffer_reserve(&vs->ws_input, 4096); | ||
| ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096); | ||
|
|
||
| if (!ret) { | ||
| if (vs->csock == -1) { | ||
| vnc_disconnect_finish(vs); | ||
| } | ||
| return; | ||
| } | ||
| vs->ws_input.offset += ret; | ||
|
|
||
| handshake_end = (uint8_t *)g_strstr_len((char *)vs->ws_input.buffer, | ||
| vs->ws_input.offset, WS_HANDSHAKE_END); | ||
| if (handshake_end) { | ||
| qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs); | ||
| vncws_process_handshake(vs, vs->ws_input.buffer, vs->ws_input.offset); | ||
| buffer_advance(&vs->ws_input, handshake_end - vs->ws_input.buffer + | ||
| strlen(WS_HANDSHAKE_END)); | ||
| } | ||
| } | ||
|
|
||
|
|
||
| long vnc_client_read_ws(VncState *vs) | ||
| { | ||
| int ret, err; | ||
| uint8_t *payload; | ||
| size_t payload_size, frame_size; | ||
| VNC_DEBUG("Read websocket %p size %zd offset %zd\n", vs->ws_input.buffer, | ||
| vs->ws_input.capacity, vs->ws_input.offset); | ||
| buffer_reserve(&vs->ws_input, 4096); | ||
| ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096); | ||
| if (!ret) { | ||
| return 0; | ||
| } | ||
| vs->ws_input.offset += ret; | ||
|
|
||
| /* make sure that nothing is left in the ws_input buffer */ | ||
| do { | ||
| err = vncws_decode_frame(&vs->ws_input, &payload, | ||
| &payload_size, &frame_size); | ||
| if (err <= 0) { | ||
| return err; | ||
| } | ||
|
|
||
| buffer_reserve(&vs->input, payload_size); | ||
| buffer_append(&vs->input, payload, payload_size); | ||
|
|
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| buffer_advance(&vs->ws_input, frame_size); | ||
| } while (vs->ws_input.offset > 0); | ||
|
|
||
| return ret; | ||
| } | ||
|
|
||
| long vnc_client_write_ws(VncState *vs) | ||
| { | ||
| long ret; | ||
| VNC_DEBUG("Write WS: Pending output %p size %zd offset %zd\n", | ||
| vs->output.buffer, vs->output.capacity, vs->output.offset); | ||
| vncws_encode_frame(&vs->ws_output, vs->output.buffer, vs->output.offset); | ||
| buffer_reset(&vs->output); | ||
| ret = vnc_client_write_buf(vs, vs->ws_output.buffer, vs->ws_output.offset); | ||
| if (!ret) { | ||
| return 0; | ||
| } | ||
|
|
||
| buffer_advance(&vs->ws_output, ret); | ||
|
|
||
| if (vs->ws_output.offset == 0) { | ||
| qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs); | ||
| } | ||
|
|
||
| return ret; | ||
| } | ||
|
|
||
| static char *vncws_extract_handshake_entry(const char *handshake, | ||
| size_t handshake_len, const char *name) | ||
| { | ||
| char *begin, *end, *ret = NULL; | ||
| char *line = g_strdup_printf("%s%s: ", WS_HANDSHAKE_DELIM, name); | ||
| begin = g_strstr_len(handshake, handshake_len, line); | ||
| if (begin != NULL) { | ||
| begin += strlen(line); | ||
| end = g_strstr_len(begin, handshake_len - (begin - handshake), | ||
| WS_HANDSHAKE_DELIM); | ||
| if (end != NULL) { | ||
| ret = g_strndup(begin, end - begin); | ||
| } | ||
| } | ||
| g_free(line); | ||
| return ret; | ||
| } | ||
|
|
||
| static void vncws_send_handshake_response(VncState *vs, const char* key) | ||
| { | ||
| char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1]; | ||
| char hash[SHA1_DIGEST_LEN]; | ||
| size_t hash_size = SHA1_DIGEST_LEN; | ||
| char *accept = NULL, *response = NULL; | ||
| gnutls_datum_t in; | ||
|
|
||
| g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1); | ||
| g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1); | ||
|
|
||
| /* hash and encode it */ | ||
| in.data = (void *)combined_key; | ||
| in.size = WS_CLIENT_KEY_LEN + WS_GUID_LEN; | ||
| if (gnutls_fingerprint(GNUTLS_DIG_SHA1, &in, hash, &hash_size) | ||
| == GNUTLS_E_SUCCESS) { | ||
| accept = g_base64_encode((guchar *)hash, SHA1_DIGEST_LEN); | ||
| } | ||
| if (accept == NULL) { | ||
| VNC_DEBUG("Hashing Websocket combined key failed\n"); | ||
| vnc_client_error(vs); | ||
| return; | ||
| } | ||
|
|
||
| response = g_strdup_printf(WS_HANDSHAKE, accept); | ||
| vnc_write(vs, response, strlen(response)); | ||
| vnc_flush(vs); | ||
|
|
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| g_free(accept); | ||
| g_free(response); | ||
|
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| vs->encode_ws = 1; | ||
| vnc_init_state(vs); | ||
| } | ||
|
|
||
| void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size) | ||
| { | ||
| char *protocols = vncws_extract_handshake_entry((const char *)line, size, | ||
| "Sec-WebSocket-Protocol"); | ||
| char *version = vncws_extract_handshake_entry((const char *)line, size, | ||
| "Sec-WebSocket-Version"); | ||
| char *key = vncws_extract_handshake_entry((const char *)line, size, | ||
| "Sec-WebSocket-Key"); | ||
|
|
||
| if (protocols && version && key | ||
| && g_strrstr(protocols, "binary") | ||
| && !strcmp(version, WS_SUPPORTED_VERSION) | ||
| && strlen(key) == WS_CLIENT_KEY_LEN) { | ||
| vncws_send_handshake_response(vs, key); | ||
| } else { | ||
| VNC_DEBUG("Defective Websockets header or unsupported protocol\n"); | ||
| vnc_client_error(vs); | ||
| } | ||
|
|
||
| g_free(protocols); | ||
| g_free(version); | ||
| g_free(key); | ||
| } | ||
|
|
||
| void vncws_encode_frame(Buffer *output, const void *payload, | ||
| const size_t payload_size) | ||
| { | ||
| size_t header_size = 0; | ||
| unsigned char opcode = WS_OPCODE_BINARY_FRAME; | ||
| union { | ||
| char buf[WS_HEAD_MAX_LEN]; | ||
| WsHeader ws; | ||
| } header; | ||
|
|
||
| if (!payload_size) { | ||
| return; | ||
| } | ||
|
|
||
| header.ws.b0 = 0x80 | (opcode & 0x0f); | ||
| if (payload_size <= 125) { | ||
| header.ws.b1 = (uint8_t)payload_size; | ||
| header_size = 2; | ||
| } else if (payload_size < 65536) { | ||
| header.ws.b1 = 0x7e; | ||
| header.ws.u.s16.l16 = cpu_to_be16((uint16_t)payload_size); | ||
| header_size = 4; | ||
| } else { | ||
| header.ws.b1 = 0x7f; | ||
| header.ws.u.s64.l64 = cpu_to_be64(payload_size); | ||
| header_size = 10; | ||
| } | ||
|
|
||
| buffer_reserve(output, header_size + payload_size); | ||
| buffer_append(output, header.buf, header_size); | ||
| buffer_append(output, payload, payload_size); | ||
| } | ||
|
|
||
| int vncws_decode_frame(Buffer *input, uint8_t **payload, | ||
| size_t *payload_size, size_t *frame_size) | ||
| { | ||
| unsigned char opcode = 0, fin = 0, has_mask = 0; | ||
| size_t header_size = 0; | ||
| uint32_t *payload32; | ||
| WsHeader *header = (WsHeader *)input->buffer; | ||
| WsMask mask; | ||
| int i; | ||
|
|
||
| if (input->offset < WS_HEAD_MIN_LEN + 4) { | ||
| /* header not complete */ | ||
| return 0; | ||
| } | ||
|
|
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| fin = (header->b0 & 0x80) >> 7; | ||
| opcode = header->b0 & 0x0f; | ||
| has_mask = (header->b1 & 0x80) >> 7; | ||
| *payload_size = header->b1 & 0x7f; | ||
|
|
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| if (opcode == WS_OPCODE_CLOSE) { | ||
| /* disconnect */ | ||
| return -1; | ||
| } | ||
|
|
||
| /* Websocket frame sanity check: | ||
| * * Websocket fragmentation is not supported. | ||
| * * All websockets frames sent by a client have to be masked. | ||
| * * Only binary encoding is supported. | ||
| */ | ||
| if (!fin || !has_mask || opcode != WS_OPCODE_BINARY_FRAME) { | ||
| VNC_DEBUG("Received faulty/unsupported Websocket frame\n"); | ||
| return -2; | ||
| } | ||
|
|
||
| if (*payload_size < 126) { | ||
| header_size = 6; | ||
| mask = header->u.m; | ||
| } else if (*payload_size == 126 && input->offset >= 8) { | ||
| *payload_size = be16_to_cpu(header->u.s16.l16); | ||
| header_size = 8; | ||
| mask = header->u.s16.m16; | ||
| } else if (*payload_size == 127 && input->offset >= 14) { | ||
| *payload_size = be64_to_cpu(header->u.s64.l64); | ||
| header_size = 14; | ||
| mask = header->u.s64.m64; | ||
| } else { | ||
| /* header not complete */ | ||
| return 0; | ||
| } | ||
|
|
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| *frame_size = header_size + *payload_size; | ||
|
|
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| if (input->offset < *frame_size) { | ||
| /* frame not complete */ | ||
| return 0; | ||
| } | ||
|
|
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| *payload = input->buffer + header_size; | ||
|
|
||
| /* unmask frame */ | ||
| /* process 1 frame (32 bit op) */ | ||
| payload32 = (uint32_t *)(*payload); | ||
| for (i = 0; i < *payload_size / 4; i++) { | ||
| payload32[i] ^= mask.u; | ||
| } | ||
| /* process the remaining bytes (if any) */ | ||
| for (i *= 4; i < *payload_size; i++) { | ||
| (*payload)[i] ^= mask.c[i % 4]; | ||
| } | ||
|
|
||
| return 1; | ||
| } |
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