flow: Make size of flow struct a multiple of 8.

The compiler wants to pad structures to a multiple of the native
datatype for the architecture, so a multiple of 4 on 32-bit platforms
and a multiple of 8 on 64-bit.  Currently the size struct flow is
a multiple of 4, so the total size with padding varies depending on
the architecture, causing build asserts to fail.  This explicitly pads
it out to a multiple of 8 for consistency.

diff --git a/lib/flow.h b/lib/flow.h
index 72f62e8..03ad32c 100644 (file)
--- a/lib/flow.h
+++ b/lib/flow.h
@@ -49,12 +49,13 @@ struct flow {
     uint8_t dl_dst[6];          /* Ethernet destination address. */
     uint8_t nw_proto;           /* IP protocol or low 8 bits of ARP opcode. */
     uint8_t nw_tos;             /* IP ToS (DSCP field, 6 bits). */
+    uint32_t reserved;         /* Reserved for 64-bit packing. */
 };
 
 /* Assert that there are FLOW_SIG_SIZE bytes of significant data in "struct
  * flow", followed by FLOW_PAD_SIZE bytes of padding. */
 #define FLOW_SIG_SIZE (40 + FLOW_N_REGS * 4)
-#define FLOW_PAD_SIZE 0
+#define FLOW_PAD_SIZE 4
 BUILD_ASSERT_DECL(offsetof(struct flow, nw_tos) == FLOW_SIG_SIZE - 1);
 BUILD_ASSERT_DECL(sizeof(((struct flow *)0)->nw_tos) == 1);
 BUILD_ASSERT_DECL(sizeof(struct flow) == FLOW_SIG_SIZE + FLOW_PAD_SIZE);