Added checking for maximum packet length.

[silc.git] / lib / silccore / silcprivate.c

diff --git a/lib/silccore/silcprivate.c b/lib/silccore/silcprivate.c
index 6136dc75349eb720bae50ac568731c558616adfc..ac99257f21595ee14a737d7fb8be608a9c1e6d84 100644 (file)
--- a/lib/silccore/silcprivate.c
+++ b/lib/silccore/silcprivate.c
@@ -29,8 +29,19 @@
 
 ******************************************************************************/
 
+/* Calculates padding length for message payload */
 #define SILC_PRIVATE_MESSAGE_PAD(__payloadlen) (16 - (__payloadlen) % 16)
 
+/* Header length plus maximum padding length */
+#define SILC_PRIVATE_MESSAGE_HLEN 4 + 16
+
+/* Returns the data length that fits to the packet.  If data length is too
+   big it will be truncated to fit to the payload. */
+#define SILC_PRIVATE_MESSAGE_DATALEN(data_len)                         \
+  ((data_len + SILC_PRIVATE_MESSAGE_HLEN) > SILC_PACKET_MAX_LEN ?      \
+   data_len - ((data_len + SILC_PRIVATE_MESSAGE_HLEN) -                \
+              SILC_PACKET_MAX_LEN) : data_len)
+
 /* Private Message Payload structure. Contents of this structure is parsed
    from SILC packets. */
 struct SilcPrivateMessagePayloadStruct {
@@ -105,6 +116,7 @@ SilcBuffer silc_private_message_payload_encode(SilcUInt16 flags,
 
   SILC_LOG_DEBUG(("Encoding private message payload"));
 
+  data_len = SILC_PRIVATE_MESSAGE_DATALEN(data_len);
   len = 4 + data_len;
 
   if (cipher) {