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 /* Includes the Private Message Payload implementation */
23 #include "silcincludes.h"
24 #include "silcprivate.h"
26 /******************************************************************************
28 Private Message Payload
30 ******************************************************************************/
32 #define SILC_PRIVATE_MESSAGE_PAD(__payloadlen) (16 - (__payloadlen) % 16)
34 /* Private Message Payload structure. Contents of this structure is parsed
36 struct SilcPrivateMessagePayloadStruct {
38 SilcUInt16 message_len;
39 unsigned char *message;
42 /* Parses private message payload returning new private mesage payload
43 structure. This also decrypts the message if the `cipher' is provided. */
45 SilcPrivateMessagePayload
46 silc_private_message_payload_parse(unsigned char *payload,
47 SilcUInt32 payload_len,
50 SilcBufferStruct buffer;
51 SilcPrivateMessagePayload newp;
54 SILC_LOG_DEBUG(("Parsing private message payload"));
56 silc_buffer_set(&buffer, payload, payload_len);
58 /* Decrypt the payload */
60 silc_cipher_decrypt(cipher, buffer.data, buffer.data,
61 buffer.len, cipher->iv);
63 newp = silc_calloc(1, sizeof(*newp));
67 /* Parse the Private Message Payload. Ignore the padding. */
68 ret = silc_buffer_unformat(&buffer,
69 SILC_STR_UI_SHORT(&newp->flags),
70 SILC_STR_UI16_NSTRING_ALLOC(&newp->message,
74 SILC_LOG_DEBUG(("Incorrect private message payload"));
78 if ((newp->message_len < 1 || newp->message_len > buffer.len)) {
79 SILC_LOG_DEBUG(("Incorrect private message payload in packet, "
87 silc_private_message_payload_free(newp);
91 /* Encodes private message payload into a buffer and returns it. If
92 the cipher is provided the packet is also encrypted here. It is provided
93 if the private message private keys are used. */
95 SilcBuffer silc_private_message_payload_encode(SilcUInt16 flags,
97 const unsigned char *data,
103 SilcUInt32 len, pad_len = 0;
104 unsigned char pad[16];
106 SILC_LOG_DEBUG(("Encoding private message payload"));
111 /* Calculate length of padding. */
112 pad_len = SILC_PRIVATE_MESSAGE_PAD(len);
115 /* Generate padding */
116 for (i = 0; i < pad_len; i++) pad[i] = silc_rng_global_get_byte();
119 /* Allocate private message payload buffer */
120 buffer = silc_buffer_alloc_size(len);
124 /* Encode the Channel Message Payload */
125 silc_buffer_format(buffer,
126 SILC_STR_UI_SHORT(flags),
127 SILC_STR_UI_SHORT(data_len),
128 SILC_STR_UI_XNSTRING(data, data_len),
129 SILC_STR_UI_XNSTRING(pad, pad_len),
133 /* Encrypt payload of the packet. */
134 silc_cipher_encrypt(cipher, buffer->data, buffer->data,
135 buffer->len, cipher->iv);
136 memset(pad, 0, sizeof(pad));
142 /* Frees Private Message Payload */
144 void silc_private_message_payload_free(SilcPrivateMessagePayload payload)
146 if (payload->message) {
147 memset(payload->message, 0, payload->message_len);
148 silc_free(payload->message);
156 silc_private_message_get_flags(SilcPrivateMessagePayload payload)
158 return payload->flags;
164 silc_private_message_get_message(SilcPrivateMessagePayload payload,
165 SilcUInt32 *message_len)
168 *message_len = payload->message_len;
170 return payload->message;