Signed-off-by: Ben Pfaff <b...@nicira.com>
---
lib/flow.c | 46 +++++++++++++++++++++++++---------------------
lib/util.h | 5 ++++-
2 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/lib/flow.c b/lib/flow.c
index d2dcc46..9dc29ee 100644
--- a/lib/flow.c
+++ b/lib/flow.c
@@ -50,25 +50,32 @@ const uint8_t flow_segment_u64s[4] = {
FLOW_U64S
};
+/* Asserts that field 'f1' follows immediately after 'f0' in struct flow,
+ * without any intervening padding. */
+#define ASSERT_SEQUENTIAL(f0, f1) \
+ BUILD_ASSERT_DECL(offsetof(struct flow, f0) \
+ + MEMBER_SIZEOF(struct flow, f0) \
+ == offsetof(struct flow, f1))
+
+/* Asserts that fields 'f0' and 'f1' are in the same 32-bit aligned word within
+ * struct flow. */
+#define ASSERT_SAME_WORD(f0, f1) \
+ BUILD_ASSERT_DECL(offsetof(struct flow, f0) / 4 \
+ == offsetof(struct flow, f1) / 4)
+
+/* Asserts that 'f0' and 'f1' are both sequential and within the same 32-bit
+ * aligned word in struct flow. */
+#define ASSERT_SEQUENTIAL_SAME_WORD(f0, f1) \
+ ASSERT_SEQUENTIAL(f0, f1); \
+ ASSERT_SAME_WORD(f0, f1)
+
/* miniflow_extract() assumes the following to be true to optimize the
* extraction process. */
-BUILD_ASSERT_DECL(offsetof(struct flow, dl_type) + 2
- == offsetof(struct flow, vlan_tci) &&
- offsetof(struct flow, dl_type) / 4
- == offsetof(struct flow, vlan_tci) / 4 );
-
-BUILD_ASSERT_DECL(offsetof(struct flow, nw_frag) + 3
- == offsetof(struct flow, nw_proto) &&
- offsetof(struct flow, nw_tos) + 2
- == offsetof(struct flow, nw_proto) &&
- offsetof(struct flow, nw_ttl) + 1
- == offsetof(struct flow, nw_proto) &&
- offsetof(struct flow, nw_frag) / 4
- == offsetof(struct flow, nw_tos) / 4 &&
- offsetof(struct flow, nw_ttl) / 4
- == offsetof(struct flow, nw_tos) / 4 &&
- offsetof(struct flow, nw_proto) / 4
- == offsetof(struct flow, nw_tos) / 4);
+ASSERT_SEQUENTIAL_SAME_WORD(dl_type, vlan_tci);
+
+ASSERT_SEQUENTIAL_SAME_WORD(nw_frag, nw_tos);
+ASSERT_SEQUENTIAL_SAME_WORD(nw_tos, nw_ttl);
+ASSERT_SEQUENTIAL_SAME_WORD(nw_ttl, nw_proto);
/* TCP flags in the middle of a BE64, zeroes in the other half. */
BUILD_ASSERT_DECL(offsetof(struct flow, tcp_flags) % 8 == 4);
@@ -80,10 +87,7 @@ BUILD_ASSERT_DECL(offsetof(struct flow, tcp_flags) % 8 == 4);
#define TCP_FLAGS_BE32(tcp_ctl) ((OVS_FORCE ovs_be32)TCP_FLAGS_BE16(tcp_ctl))
#endif
-BUILD_ASSERT_DECL(offsetof(struct flow, tp_src) + 2
- == offsetof(struct flow, tp_dst) &&
- offsetof(struct flow, tp_src) / 4
- == offsetof(struct flow, tp_dst) / 4);
+ASSERT_SEQUENTIAL_SAME_WORD(tp_src, tp_dst);
/* Removes 'size' bytes from the head end of '*datap', of size '*sizep', which
* must contain at least 'size' bytes of data. Returns the first byte of data
diff --git a/lib/util.h b/lib/util.h
index 78abfd3..906b9a5 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -199,6 +199,9 @@ ovs_prefetch_range(const void *start, size_t size)
((char *) &(OBJECT)->MEMBER - (char *) (OBJECT))
#endif
+/* Yields the size of MEMBER within STRUCT. */
+#define MEMBER_SIZEOF(STRUCT, MEMBER) (sizeof(((STRUCT *) NULL)->MEMBER))
+
/* Given POINTER, the address of the given MEMBER in a STRUCT object, returns
the STRUCT object. */
#define CONTAINER_OF(POINTER, STRUCT, MEMBER) \
--
2.1.3
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