Merge pull request #100 from painless-security/milestone/monitoring

[trust_router.git] / common / tr_rand_id.c

diff --git a/common/tr_rand_id.c b/common/tr_rand_id.c
new file mode 100644 (file)
index 0000000..a2a0a10
--- /dev/null
+++ b/common/tr_rand_id.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2018, JANET(UK)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of JANET(UK) nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <openssl/rand.h>
+#include <talloc.h>
+
+#include <tr_rand_id.h>
+
+static char *bytes_to_hex(TALLOC_CTX *mem_ctx, const unsigned char *bytes, size_t len)
+{
+  char *hex = talloc_size(mem_ctx, 1 + len * 2 * sizeof(char));
+  char *p = NULL;
+
+  if (hex) {
+    p = hex;
+    while(len--) {
+      p += sprintf(p, "%02x", *(bytes++));
+    }
+  }
+
+  return hex;
+}
+
+/**
+ * Generate n random bytes of data
+ *
+ * @param dst destination buffer, at least n bytes long
+ * @param n number of bytes to generate
+ * @return -1 on error
+ */
+static int random_bytes(unsigned char *dst, size_t n)
+{
+  return RAND_pseudo_bytes(dst, n);
+}
+
+#define ID_LENGTH 15
+/**
+ * Generate a random ID
+ *
+ * @param mem_ctx talloc context for the result
+ * @return random string of hex characters or null if it is unable to generate them
+ */
+char *tr_random_id(TALLOC_CTX *mem_ctx)
+{
+  unsigned char bytes[ID_LENGTH];
+  char *hex = NULL;
+
+  if (random_bytes(bytes, ID_LENGTH) >= 0)
+    hex = bytes_to_hex(mem_ctx, bytes, ID_LENGTH);
+
+  return hex;
+}