5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 1997 - 2001 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
20 /* Channel Payload, Channel Message Payload and Channel Key Payload
24 #include "silcincludes.h"
25 #include "silcchannel.h"
27 /******************************************************************************
31 ******************************************************************************/
33 /* Channel Message Payload structure. Contents of this structure is parsed
35 struct SilcChannelPayloadStruct {
36 unsigned short name_len;
37 unsigned char *channel_name;
38 unsigned short id_len;
39 unsigned char *channel_id;
43 /* Parses channel payload returning new channel payload structure. */
45 SilcChannelPayload silc_channel_payload_parse(SilcBuffer buffer)
47 SilcChannelPayload new;
50 SILC_LOG_DEBUG(("Parsing channel payload"));
52 new = silc_calloc(1, sizeof(*new));
54 /* Parse the Channel Payload. Ignore the padding. */
55 ret = silc_buffer_unformat(buffer,
56 SILC_STR_UI16_NSTRING_ALLOC(&new->channel_name,
58 SILC_STR_UI16_NSTRING_ALLOC(&new->channel_id,
60 SILC_STR_UI_INT(&new->mode),
65 if ((new->name_len < 1 || new->name_len > buffer->len) ||
66 (new->id_len < 1 || new->id_len > buffer->len)) {
67 SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
74 silc_channel_payload_free(new);
78 /* Parses list of channel payloads returning list of payloads. */
80 SilcDList silc_channel_payload_parse_list(SilcBuffer buffer)
83 SilcChannelPayload new;
86 SILC_LOG_DEBUG(("Parsing channel payload list"));
88 list = silc_dlist_init();
91 new = silc_calloc(1, sizeof(*new));
92 ret = silc_buffer_unformat(buffer,
93 SILC_STR_UI16_NSTRING_ALLOC(&new->channel_name,
95 SILC_STR_UI16_NSTRING_ALLOC(&new->channel_id,
97 SILC_STR_UI_INT(&new->mode),
102 if ((new->name_len < 1 || new->name_len > buffer->len) ||
103 (new->id_len < 1 || new->id_len > buffer->len)) {
104 SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
108 len = 2 + new->name_len + 2 + new->id_len + 4;
109 if (buffer->len < len)
111 silc_buffer_pull(buffer, len);
113 silc_dlist_add(list, new);
119 silc_channel_payload_list_free(list);
123 /* Encode new channel payload and returns it as buffer. */
125 SilcBuffer silc_channel_payload_encode(unsigned char *channel_name,
126 unsigned short channel_name_len,
127 unsigned char *channel_id,
128 unsigned int channel_id_len,
133 SILC_LOG_DEBUG(("Encoding message payload"));
135 buffer = silc_buffer_alloc(2 + channel_name_len + 2 + channel_id_len + 4);
136 silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
138 /* Encode the Channel Payload */
139 silc_buffer_format(buffer,
140 SILC_STR_UI_SHORT(channel_name_len),
141 SILC_STR_UI_XNSTRING(channel_name, channel_name_len),
142 SILC_STR_UI_SHORT(channel_id_len),
143 SILC_STR_UI_XNSTRING(channel_id, channel_id_len),
144 SILC_STR_UI_INT(mode),
150 /* Free's Channel Payload */
152 void silc_channel_payload_free(SilcChannelPayload payload)
154 silc_free(payload->channel_name);
155 silc_free(payload->channel_id);
159 /* Free's list of Channel Payloads */
161 void silc_channel_payload_list_free(SilcDList list)
163 SilcChannelPayload entry;
165 silc_dlist_start(list);
166 while ((entry = silc_dlist_get(list)) != SILC_LIST_END) {
167 silc_free(entry->channel_name);
168 silc_free(entry->channel_id);
170 silc_dlist_del(list, entry);
173 silc_dlist_uninit(list);
176 /* Return the channel name */
178 unsigned char *silc_channel_get_name(SilcChannelPayload payload,
179 unsigned int *channel_name_len)
181 if (channel_name_len)
182 *channel_name_len = payload->name_len;
184 return payload->channel_name;
187 /* Return the channel ID */
189 unsigned char *silc_channel_get_id(SilcChannelPayload payload,
190 unsigned int *channel_id_len)
193 *channel_id_len = payload->id_len;
195 return payload->channel_id;
198 /* Return the channel ID as parsed ID. */
200 SilcChannelID *silc_channel_get_id_parse(SilcChannelPayload payload)
202 return silc_id_str2id(payload->channel_id, payload->id_len,
206 /* Return the mode. The mode is arbitrary. It can be the mode of the
207 channel or perhaps the mode of the client on the channel. The protocol
208 dictates what the usage of the mode is in different circumstances. */
210 unsigned int silc_channel_get_mode(SilcChannelPayload payload)
212 return payload->mode;
215 /******************************************************************************
217 Channel Message Payload
219 ******************************************************************************/
221 /* Channel Message Payload structure. Contents of this structure is parsed
222 from SILC packets. */
223 struct SilcChannelMessagePayloadStruct {
224 unsigned short flags;
225 unsigned short data_len;
231 /* Decrypts the channel message payload. */
233 int silc_channel_message_payload_decrypt(unsigned char *data,
238 unsigned int iv_len, mac_len;
239 unsigned char *end, *mac, mac2[32];
241 /* Decrypt the channel message. First push the IV out of the packet.
242 The IV is used in the decryption process. Then decrypt the message.
243 After decyprtion, take the MAC from the decrypted packet, compute MAC
244 and compare the MACs. If they match, the decryption was successfull
245 and we have the channel message ready to be displayed. */
246 end = data + data_len;
248 /* Push the IV out of the packet */
249 iv_len = silc_cipher_get_block_len(cipher);
251 /* Decrypt the channel message */
252 silc_cipher_decrypt(cipher, data, data, data_len - iv_len, (end - iv_len));
256 mac_len = silc_hmac_len(hmac);
257 mac = (end - iv_len - mac_len);
259 /* Check the MAC of the message */
260 SILC_LOG_DEBUG(("Checking channel message MACs"));
261 silc_hmac_make(hmac, data, (data_len - iv_len - mac_len), mac2, &mac_len);
262 if (memcmp(mac, mac2, mac_len)) {
263 SILC_LOG_DEBUG(("Channel message MACs does not match"));
266 SILC_LOG_DEBUG(("MAC is Ok"));
272 /* Parses channel message payload returning new channel payload structure.
273 This also decrypts it and checks the MAC. */
275 SilcChannelMessagePayload
276 silc_channel_message_payload_parse(SilcBuffer buffer,
280 SilcChannelMessagePayload new;
282 unsigned int iv_len, mac_len;
284 SILC_LOG_DEBUG(("Parsing channel message payload"));
286 /* Decrypt the payload */
287 ret = silc_channel_message_payload_decrypt(buffer->data, buffer->len,
292 iv_len = silc_cipher_get_block_len(cipher);
293 mac_len = silc_hmac_len(hmac);
295 new = silc_calloc(1, sizeof(*new));
297 /* Parse the Channel Message Payload. Ignore the padding. */
298 ret = silc_buffer_unformat(buffer,
299 SILC_STR_UI_SHORT(&new->flags),
300 SILC_STR_UI16_NSTRING_ALLOC(&new->data,
302 SILC_STR_UI16_NSTRING(NULL, NULL),
303 SILC_STR_UI_XNSTRING(&new->mac, mac_len),
304 SILC_STR_UI_XNSTRING(&new->iv, iv_len),
309 if (new->data_len < 1 || new->data_len > buffer->len) {
310 SILC_LOG_ERROR(("Incorrect channel messaeg payload in packet, "
318 silc_channel_message_payload_free(new);
322 /* Encodes channel message payload into a buffer and returns it. This is used
323 to add channel message payload into a packet. As the channel payload is
324 encrypted separately from other parts of the packet padding must
325 be applied to the payload. */
327 SilcBuffer silc_channel_message_payload_encode(unsigned short flags,
328 unsigned short data_len,
330 unsigned short iv_len,
337 unsigned int len, pad_len, mac_len;
338 unsigned char pad[SILC_PACKET_MAX_PADLEN];
339 unsigned char mac[32];
341 SILC_LOG_DEBUG(("Encoding channel message payload"));
343 /* Calculate length of padding. IV is not included into the calculation
344 since it is not encrypted. */
345 mac_len = silc_hmac_len(hmac);
346 len = 6 + data_len + mac_len;
347 pad_len = SILC_PACKET_PADLEN((len + 2));
349 /* Allocate channel payload buffer */
350 len += pad_len + iv_len;
351 buffer = silc_buffer_alloc(len);
353 /* Generate padding */
354 for (i = 0; i < pad_len; i++) pad[i] = silc_rng_global_get_byte();
356 /* Encode the Channel Message Payload */
357 silc_buffer_pull_tail(buffer, 6 + data_len + pad_len);
358 silc_buffer_format(buffer,
359 SILC_STR_UI_SHORT(flags),
360 SILC_STR_UI_SHORT(data_len),
361 SILC_STR_UI_XNSTRING(data, data_len),
362 SILC_STR_UI_SHORT(pad_len),
363 SILC_STR_UI_XNSTRING(pad, pad_len),
366 /* Compute the MAC of the channel message data */
367 silc_hmac_make(hmac, buffer->data, buffer->len, mac, &mac_len);
369 /* Put rest of the data to the payload */
370 silc_buffer_pull_tail(buffer, mac_len + iv_len);
371 silc_buffer_pull(buffer, 6 + data_len + pad_len);
372 silc_buffer_format(buffer,
373 SILC_STR_UI_XNSTRING(mac, mac_len),
374 SILC_STR_UI_XNSTRING(iv, iv_len),
376 silc_buffer_push(buffer, 6 + data_len + pad_len);
378 /* Encrypt payload of the packet. This is encrypted with the channel key. */
379 silc_cipher_encrypt(cipher, buffer->data, buffer->data,
380 buffer->len - iv_len, iv);
382 memset(pad, 0, sizeof(pad));
383 memset(mac, 0, sizeof(mac));
388 /* Free's Channel Message Payload */
390 void silc_channel_message_payload_free(SilcChannelMessagePayload payload)
393 memset(payload->data, 0, payload->data_len);
394 silc_free(payload->data);
401 unsigned char *silc_channel_message_get_data(SilcChannelMessagePayload payload,
402 unsigned int *data_len)
405 *data_len = payload->data_len;
407 return payload->data;
410 /* Return MAC. The caller knows the length of the MAC */
412 unsigned char *silc_channel_mesage_get_mac(SilcChannelMessagePayload payload)
417 /* Return IV. The caller knows the length of the IV */
419 unsigned char *silc_channel_message_get_iv(SilcChannelMessagePayload payload)
424 /******************************************************************************
428 ******************************************************************************/
430 /* Channel Key Payload structrue. Channel keys are parsed from SILC
431 packets into this structure. */
432 struct SilcChannelKeyPayloadStruct {
433 unsigned short id_len;
435 unsigned short cipher_len;
436 unsigned char *cipher;
437 unsigned short key_len;
441 /* Parses channel key payload returning new channel key payload structure */
443 SilcChannelKeyPayload silc_channel_key_payload_parse(SilcBuffer buffer)
445 SilcChannelKeyPayload new;
448 SILC_LOG_DEBUG(("Parsing channel key payload"));
450 new = silc_calloc(1, sizeof(*new));
452 /* Parse the Channel Key Payload */
454 silc_buffer_unformat(buffer,
455 SILC_STR_UI16_NSTRING_ALLOC(&new->id, &new->id_len),
456 SILC_STR_UI16_NSTRING_ALLOC(&new->cipher,
458 SILC_STR_UI16_NSTRING_ALLOC(&new->key, &new->key_len),
463 if (new->id_len < 1 || new->key_len < 1 || new->cipher_len < 1) {
464 SILC_LOG_ERROR(("Incorrect channel key payload in packet"));
474 silc_free(new->cipher);
481 /* Encodes channel key payload into a buffer and returns it. This is used
482 to add channel key payload into a packet. */
484 SilcBuffer silc_channel_key_payload_encode(unsigned short id_len,
486 unsigned short cipher_len,
487 unsigned char *cipher,
488 unsigned short key_len,
494 SILC_LOG_DEBUG(("Encoding channel key payload"));
496 /* Allocate channel payload buffer. Length is 2 + id + 2 + key +
498 len = 2 + id_len + 2 + key_len + 2 + cipher_len;
499 buffer = silc_buffer_alloc(len);
501 silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
503 /* Encode the Channel Payload */
504 silc_buffer_format(buffer,
505 SILC_STR_UI_SHORT(id_len),
506 SILC_STR_UI_XNSTRING(id, id_len),
507 SILC_STR_UI_SHORT(cipher_len),
508 SILC_STR_UI_XNSTRING(cipher, cipher_len),
509 SILC_STR_UI_SHORT(key_len),
510 SILC_STR_UI_XNSTRING(key, key_len),
516 /* Free's Channel Key Payload */
518 void silc_channel_key_payload_free(SilcChannelKeyPayload payload)
522 silc_free(payload->id);
524 silc_free(payload->cipher);
526 memset(payload->key, 0, payload->key_len);
527 silc_free(payload->key);
535 unsigned char *silc_channel_key_get_id(SilcChannelKeyPayload payload,
536 unsigned int *id_len)
539 *id_len = payload->id_len;
544 /* Return cipher name */
546 unsigned char *silc_channel_key_get_cipher(SilcChannelKeyPayload payload,
547 unsigned int *cipher_len)
550 *cipher_len = payload->cipher_len;
552 return payload->cipher;
557 unsigned char *silc_channel_key_get_key(SilcChannelKeyPayload payload,
558 unsigned int *key_len)
561 *key_len = payload->key_len;