* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/*
+ * Macros to extract possibly-unaligned big-endian integral values.
+ */
+#ifdef LBL_ALIGN
+/*
+ * The processor doesn't natively handle unaligned loads.
+ */
+#if defined(__GNUC__) && defined(HAVE___ATTRIBUTE__) && \
+ (defined(__alpha) || defined(__alpha__) || \
+ defined(__mips) || defined(__mips__))
+
+/*
+ * This is a GCC-compatible compiler and we have __attribute__, which
+ * we assume that mean we have __attribute__((packed)), and this is
+ * MIPS or Alpha, which has instructions that can help when doing
+ * unaligned loads.
+ *
+ * Declare packed structures containing a uint16_t and a uint32_t,
+ * cast the pointer to point to one of those, and fetch through it;
+ * the GCC manual doesn't appear to explicitly say that
+ * __attribute__((packed)) causes the compiler to generate unaligned-safe
+ * code, but it apppears to do so.
+ *
+ * We do this in case the compiler can generate code using those
+ * instructions to do an unaligned load and pass stuff to "ntohs()" or
+ * "ntohl()", which might be better than than the code to fetch the
+ * bytes one at a time and assemble them. (That might not be the
+ * case on a little-endian platform, such as DEC's MIPS machines and
+ * Alpha machines, where "ntohs()" and "ntohl()" might not be done
+ * inline.)
+ *
+ * We do this only for specific architectures because, for example,
+ * at least some versions of GCC, when compiling for 64-bit SPARC,
+ * generate code that assumes alignment if we do this.
*
- * @(#) $Header: /tcpdump/master/tcpdump/extract.h,v 1.16 2000-10-03 02:54:55 itojun Exp $ (LBL)
+ * XXX - add other architectures and compilers as possible and
+ * appropriate.
+ *
+ * HP's C compiler, indicated by __HP_cc being defined, supports
+ * "#pragma unaligned N" in version A.05.50 and later, where "N"
+ * specifies a number of bytes at which the typedef on the next
+ * line is aligned, e.g.
+ *
+ * #pragma unalign 1
+ * typedef uint16_t unaligned_uint16_t;
+ *
+ * to define unaligned_uint16_t as a 16-bit unaligned data type.
+ * This could be presumably used, in sufficiently recent versions of
+ * the compiler, with macros similar to those below. This would be
+ * useful only if that compiler could generate better code for PA-RISC
+ * or Itanium than would be generated by a bunch of shifts-and-ORs.
+ *
+ * DEC C, indicated by __DECC being defined, has, at least on Alpha,
+ * an __unaligned qualifier that can be applied to pointers to get the
+ * compiler to generate code that does unaligned loads and stores when
+ * dereferencing the pointer in question.
+ *
+ * XXX - what if the native C compiler doesn't support
+ * __attribute__((packed))? How can we get it to generate unaligned
+ * accesses for *specific* items?
*/
+typedef struct {
+ uint16_t val;
+} __attribute__((packed)) unaligned_uint16_t;
-/* Network to host order macros */
+typedef struct {
+ uint32_t val;
+} __attribute__((packed)) unaligned_uint32_t;
-#ifdef LBL_ALIGN
-#define EXTRACT_16BITS(p) \
- ((u_int16_t)*((u_int8_t *)(p) + 0) << 8 | \
- (u_int16_t)*((u_int8_t *)(p) + 1))
-#define EXTRACT_32BITS(p) \
- ((u_int32_t)*((u_int8_t *)(p) + 0) << 24 | \
- (u_int32_t)*((u_int8_t *)(p) + 1) << 16 | \
- (u_int32_t)*((u_int8_t *)(p) + 2) << 8 | \
- (u_int32_t)*((u_int8_t *)(p) + 3))
-#else
+static inline uint16_t
+EXTRACT_16BITS(const void *p)
+{
+ return ((uint16_t)ntohs(((const unaligned_uint16_t *)(p))->val));
+}
+
+static inline uint32_t
+EXTRACT_32BITS(const void *p)
+{
+ return ((uint32_t)ntohl(((const unaligned_uint32_t *)(p))->val));
+}
+
+static inline uint64_t
+EXTRACT_64BITS(const void *p)
+{
+ return ((uint64_t)(((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 0)->val)) << 32 |
+ ((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 1)->val)) << 0));
+}
+
+#else /* have to do it a byte at a time */
+/*
+ * This isn't a GCC-compatible compiler, we don't have __attribute__,
+ * or we do but we don't know of any better way with this instruction
+ * set to do unaligned loads, so do unaligned loads of big-endian
+ * quantities the hard way - fetch the bytes one at a time and
+ * assemble them.
+ */
#define EXTRACT_16BITS(p) \
- ((u_int16_t)ntohs(*(u_int16_t *)(p)))
+ ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 0)) << 8) | \
+ ((uint16_t)(*((const uint8_t *)(p) + 1)) << 0)))
#define EXTRACT_32BITS(p) \
- ((u_int32_t)ntohl(*(u_int32_t *)(p)))
-#endif
+ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 24) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 16) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 8) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 3)) << 0)))
+#define EXTRACT_64BITS(p) \
+ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 56) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 48) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 40) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 32) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 24) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 16) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 8) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 7)) << 0)))
+#endif /* must special-case unaligned accesses */
+#else /* LBL_ALIGN */
+/*
+ * The processor natively handles unaligned loads, so we can just
+ * cast the pointer and fetch through it.
+ */
+static inline uint16_t
+EXTRACT_16BITS(const void *p)
+{
+ return ((uint16_t)ntohs(*(const uint16_t *)(p)));
+}
+
+static inline uint32_t
+EXTRACT_32BITS(const void *p)
+{
+ return ((uint32_t)ntohl(*(const uint32_t *)(p)));
+}
+
+static inline uint64_t
+EXTRACT_64BITS(const void *p)
+{
+ return ((uint64_t)(((uint64_t)ntohl(*((const uint32_t *)(p) + 0))) << 32 |
+ ((uint64_t)ntohl(*((const uint32_t *)(p) + 1))) << 0));
+
+}
+
+#endif /* LBL_ALIGN */
#define EXTRACT_24BITS(p) \
- ((u_int32_t)*((u_int8_t *)(p) + 0) << 16 | \
- (u_int32_t)*((u_int8_t *)(p) + 1) << 8 | \
- (u_int32_t)*((u_int8_t *)(p) + 2))
+ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 16) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 0)))
+
+#define EXTRACT_40BITS(p) \
+ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 32) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 24) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 8) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 0)))
-/* Little endian protocol host order macros */
+#define EXTRACT_48BITS(p) \
+ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 40) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 32) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 24) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 16) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 8) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 0)))
+#define EXTRACT_56BITS(p) \
+ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 48) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 40) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 32) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 16) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 8) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 0)))
+
+/*
+ * Macros to extract possibly-unaligned little-endian integral values.
+ * XXX - do loads on little-endian machines that support unaligned loads?
+ */
#define EXTRACT_LE_8BITS(p) (*(p))
#define EXTRACT_LE_16BITS(p) \
- ((u_int16_t)*((u_int8_t *)(p) + 1) << 8 | \
- (u_int16_t)*((u_int8_t *)(p) + 0))
+ ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 1)) << 8) | \
+ ((uint16_t)(*((const uint8_t *)(p) + 0)) << 0)))
#define EXTRACT_LE_32BITS(p) \
- ((u_int32_t)*((u_int8_t *)(p) + 3) << 24 | \
- (u_int32_t)*((u_int8_t *)(p) + 2) << 16 | \
- (u_int32_t)*((u_int8_t *)(p) + 1) << 8 | \
- (u_int32_t)*((u_int8_t *)(p) + 0))
+ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 3)) << 24) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0)))
+#define EXTRACT_LE_24BITS(p) \
+ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \
+ ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0)))
+#define EXTRACT_LE_64BITS(p) \
+ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 7)) << 56) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 48) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 40) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 32) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 8) | \
+ ((uint64_t)(*((const uint8_t *)(p) + 0)) << 0)))
+
+/*
+ * Macros to check the presence of the values in question.
+ */
+#define ND_TTEST_8BITS(p) ND_TTEST2(*(p), 1)
+#define ND_TCHECK_8BITS(p) ND_TCHECK2(*(p), 1)
+
+#define ND_TTEST_16BITS(p) ND_TTEST2(*(p), 2)
+#define ND_TCHECK_16BITS(p) ND_TCHECK2(*(p), 2)
+
+#define ND_TTEST_24BITS(p) ND_TTEST2(*(p), 3)
+#define ND_TCHECK_24BITS(p) ND_TCHECK2(*(p), 3)
+
+#define ND_TTEST_32BITS(p) ND_TTEST2(*(p), 4)
+#define ND_TCHECK_32BITS(p) ND_TCHECK2(*(p), 4)
+
+#define ND_TTEST_40BITS(p) ND_TTEST2(*(p), 5)
+#define ND_TCHECK_40BITS(p) ND_TCHECK2(*(p), 5)
+
+#define ND_TTEST_48BITS(p) ND_TTEST2(*(p), 6)
+#define ND_TCHECK_48BITS(p) ND_TCHECK2(*(p), 6)
+
+#define ND_TTEST_56BITS(p) ND_TTEST2(*(p), 7)
+#define ND_TCHECK_56BITS(p) ND_TCHECK2(*(p), 7)
+
+#define ND_TTEST_64BITS(p) ND_TTEST2(*(p), 8)
+#define ND_TCHECK_64BITS(p) ND_TCHECK2(*(p), 8)
projects / tcpdump / blobdiff