Another major re-write of the fwknop library.

git-svn-id: file:///home/mbr/svn/fwknop/trunk@13 510a4753-2344-4c79-9c09-4d669213fbeb

lib/fko_encode.c

@@ -0,0 +1,159 @@
+/* $Id$
+ *****************************************************************************
+ *
+ * File:    fko_encode.c
+ *
+ * Author:  Damien S. Stuart
+ *
+ * Purpose: Encodes some pieces of the spa data then puts together all of
+ *          the necessary pieces to gether to create the single encoded
+ *          message string.
+ *
+ * Copyright (C) 2008 Damien Stuart (dstuart@dstuart.org)
+ *
+ *  License (GNU Public License):
+ *
+ *     This program 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 program; if not, write to the Free Software
+ *     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+ *     USA
+ *
+ *****************************************************************************
+*/
+#include "fko_common.h"
+#include "fko.h"
+#include "base64.h"
+#include "digest.h"
+
+/* A rough way to make enough space for a base64 encoded version of
+ * the given string, encode it, and return it.
+*/
+int append_b64(char* tbuf, char *str)
+{
+    int   len = strlen(str);
+    char *bs;
+
+    if((bs = malloc(((len/3)*4)+8)) == NULL)
+        return(FKO_ERROR_MEMORY_ALLOCATION);
+
+    b64_encode((unsigned char*)str, bs, len);
+
+    /* --DSS XXX: make sure to check here if later decoding
+     *            becomes a problem.
+    */
+    strip_b64_eq(bs);
+
+    strlcat(tbuf, bs, FKO_ENCODE_TMP_BUF_SIZE);
+
+    free(bs);
+
+    return(FKO_SUCCESS);
+}
+
+/* Set the SPA encryption type.
+*/
+int fko_encode_spa_data(fko_ctx_t *ctx)
+{
+    int     res, offset = 0;
+    char    tbuf[FKO_ENCODE_TMP_BUF_SIZE] = {0};
+
+    /* Must be initialized
+    */
+    if(!CTX_INITIALIZED(ctx))
+        return(FKO_ERROR_CTX_NOT_INITIALIZED);
+
+    /* Check prerequisites.
+     * --DSS XXX:  Needs review.  Also, we could make this more robust (or
+     *             (at leaset expand the error reporting for the missing
+     *             data).
+    */
+    if(  ctx->username == NULL || strlen(ctx->username) == 0
+      || ctx->version  == NULL || strlen(ctx->version)  == 0
+      || ctx->message  == NULL || strlen(ctx->message)  == 0)
+    {
+        return(FKO_ERROR_INCOMPLETE_SPA_DATA);
+    }
+
+    if(ctx->message_type == FKO_NAT_ACCESS_MSG)
+    {
+        if(ctx->nat_access == NULL || strlen(ctx->nat_access) == 0)
+            return(FKO_ERROR_INCOMPLETE_SPA_DATA);
+    }
+ 
+    /* Put it together a piece at a time, starting with the rand val.
+    */
+    strcpy(tbuf, ctx->rand_val);
+
+    /* Add the base64-encoded username.
+    */
+    strlcat(tbuf, ":", FKO_ENCODE_TMP_BUF_SIZE);
+    if((res = append_b64(tbuf, ctx->username)) != FKO_SUCCESS)
+        return(res);
+    
+    /* Add the timestamp.
+    */
+    offset = strlen(tbuf);
+    sprintf(((char*)tbuf+offset), ":%u:", ctx->timestamp);
+
+    /* Add the version string.
+    */
+    strlcat(tbuf, ctx->version, FKO_ENCODE_TMP_BUF_SIZE);
+
+    /* Add the message type value.
+    */
+    offset = strlen(tbuf);
+    sprintf(((char*)tbuf+offset), ":%i:", ctx->message_type);
+ 
+    /* Add the base64-encoded SPA message.
+    */
+    if((res = append_b64(tbuf, ctx->message)) != FKO_SUCCESS)
+        return(res);
+    
+    /** --DSS TODO:  Need to address nat_access, server_auth
+    ***        XXX:  and client_timeout message types here
+    **/
+
+    /* If encoded_msg is not null, then we assume it needs to
+     * be freed before re-assignment.
+    */
+    if(ctx->encoded_msg != NULL)
+        free(ctx->encoded_msg);
+
+    /* Copy our encoded data into the context.
+    */
+    ctx->encoded_msg = strdup(tbuf);
+
+    if(ctx->encoded_msg == NULL)
+        return(FKO_ERROR_MEMORY_ALLOCATION);
+
+    ctx->state |= FKO_SPA_ENCODE_MESSAGE_SET;
+
+    /* At this point we can compute the digest for this SPA data.
+    */
+    if((res = fko_set_spa_digest(ctx)) != FKO_SUCCESS)
+        return(res);
+
+    return(FKO_SUCCESS);
+}
+
+/* Return the SPA encryption type.
+*/
+int fko_decode_spa_data(fko_ctx_t *ctx)
+{
+    /* Must be initialized
+    */
+    if(!CTX_INITIALIZED(ctx))
+        return(FKO_ERROR_CTX_NOT_INITIALIZED);
+
+
+
+    return(FKO_SUCCESS);
+}
+
+
+/***EOF***/