From: Alan T. DeKok <aland@freeradius.org>
Date: Fri, 8 Jan 2021 14:49:49 +0000 (-0500)
Subject: add fr_type_cast()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7eebe160f8372e2c89dae1069b4ccc97ed3060a0;p=thirdparty%2Ffreeradius-server.git

add fr_type_cast()

which checks if you can cast type src->dst
---

diff --git a/src/lib/util/types.h b/src/lib/util/types.h
index b357bf77cfc..4f5bf8b7ad6 100644
--- a/src/lib/util/types.h
+++ b/src/lib/util/types.h
@@ -31,6 +31,7 @@ extern "C" {
 
 /** Internal data types used within libfreeradius
  *
+ *  Order is important!  Please see fr_type_promote() for details.
  */
 typedef enum {
 	FR_TYPE_INVALID = 0,			//!< Invalid (uninitialised) attribute type.
@@ -65,10 +66,10 @@ typedef enum {
 	FR_TYPE_FLOAT32,			//!< Single precision floating point.
 	FR_TYPE_FLOAT64,			//!< Double precision floating point.
 
-	FR_TYPE_DATE,				//!< 32 Bit Unix timestamp.
-
 	FR_TYPE_TIME_DELTA,			//!< A period of time measured in nanoseconds.
 
+	FR_TYPE_DATE,				//!< Unix time stamp, always has value >2^31
+
 	FR_TYPE_TLV,				//!< Contains nested attributes.
 	FR_TYPE_STRUCT,				//!< like TLV, but without T or L, and fixed-width children
 
@@ -210,6 +211,11 @@ typedef enum {
 	FR_TYPE_STRING: \
 	case FR_TYPE_DATE
 
+/*
+ *  In value.c, but should likely be here.
+ */
+bool fr_type_cast(fr_type_t dst, fr_type_t src);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/lib/util/value.c b/src/lib/util/value.c
index 421a03758ef..fc88522c3d3 100644
--- a/src/lib/util/value.c
+++ b/src/lib/util/value.c
@@ -5181,3 +5181,106 @@ fr_value_box_t *fr_value_box_list_get(fr_value_box_t *head, int index)
 
 	return head;
 }
+
+#define O(_x) [FR_TYPE_ ## _x] = true
+
+/*
+ *	Can we promote [src][dst] -> dst
+ *		dst is not octets / string
+ *		src and dst are both FR_TYPE_VALUE
+ */
+static const bool type_promote_table[FR_TYPE_MAX][FR_TYPE_MAX] = {
+	[FR_TYPE_IPV4_ADDR] = {
+		O(IPV4_PREFIX),
+		O(IPV6_ADDR),
+		O(IPV6_PREFIX),
+		O(UINT32), /* ipv4 addresses are uint32 */
+	},
+	[FR_TYPE_IPV4_PREFIX] = {
+		O(IPV4_ADDR),	/* if the prefix is /32 */
+		O(IPV6_ADDR),
+		O(IPV6_PREFIX),
+	},
+	[FR_TYPE_IPV6_ADDR] = {
+		O(IPV6_PREFIX),
+	},
+	[FR_TYPE_IPV6_PREFIX] = {
+		O(IPV6_ADDR),	/* if the prefix is /128 */
+	},
+
+	[FR_TYPE_ETHERNET] = {
+		O(UINT64),
+	},
+
+	[FR_TYPE_UINT64] = {
+		O(ETHERNET),
+	},
+
+	[FR_TYPE_DATE] = {	/* in 2021, dates always have values 2^31 or more */
+		O(UINT32),
+		O(UINT64),
+		O(INT32),
+		O(INT64),
+		O(SIZE),
+		O(FLOAT32),
+		O(FLOAT64),
+		O(TIME_DELTA),
+	},
+
+	[FR_TYPE_TIME_DELTA] = {
+		O(DATE),
+	},
+
+	[FR_TYPE_UINT32] = {
+		O(IPV4_ADDR),
+	},
+
+};
+
+
+/** Return if we're allowed to cast the types.
+ *
+ * @param dst	the destination type we wish to cast to
+ * @param src	the source type we wish to cast to
+ *
+ */
+bool fr_type_cast(fr_type_t dst, fr_type_t src)
+{
+	/*
+	 *	Invalid casts.
+	 */
+	if ((dst == FR_TYPE_INVALID) || (src >= FR_TYPE_TLV)) return false;
+	if ((src == FR_TYPE_INVALID) || (dst >= FR_TYPE_TLV)) return false;
+
+	if (src == dst) return true;
+
+	/*
+	 *	Anything can be converted to octets or strings.
+	 */
+	if (dst == FR_TYPE_OCTETS) return true;
+	if (dst == FR_TYPE_STRING) return true;
+
+	/*
+	 *	Strings and octets can be converted to anything.  We
+	 *	do run-time checks on the values to see if they fit.
+	 */
+	if (src == FR_TYPE_OCTETS) return true;
+	if (src == FR_TYPE_STRING) return true;
+
+	/*
+	 *	Any integer-style thing can be cast to any other
+	 *	integer-style thing.  Mostly.  We do run-time checks
+	 *	on values to see if they fit.
+	 */
+	if (((src >= FR_TYPE_BOOL) && (src <= FR_TYPE_TIME_DELTA)) &&
+	    ((dst >= FR_TYPE_BOOL) && (dst <= FR_TYPE_TIME_DELTA))) {
+		return true;
+	}
+
+	/*
+	 *	That takes care of the simple cases.  :( Now to the
+	 *	complex ones.  Instead of masses of if / then / else,
+	 *	we just use a lookup table.
+	 */
+	return type_promote_table[src][dst];
+}