[fault] Generalise NETDEV_DISCARD_RATE fault injection mechanism

Provide a generic inject_fault() function that can be used to inject
random faults with configurable probabilities.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/include/ipxe/fault.h b/src/include/ipxe/fault.h
new file mode 100644
index 000000000..32aa06484
--- /dev/null
+++ b/src/include/ipxe/fault.h
@@ -0,0 +1,32 @@
+#ifndef _IPXE_FAULT_H
+#define _IPXE_FAULT_H
+
+/** @file
+ *
+ * Fault injection
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <config/fault.h>
+
+extern int inject_fault_nonzero ( unsigned int rate );
+
+/**
+ * Inject fault with a specified probability
+ *
+ * @v rate		Reciprocal of fault probability (zero for no faults)
+ * @ret rc		Return status code
+ */
+static inline __attribute__ (( always_inline )) int
+inject_fault ( unsigned int rate ) {
+
+	/* Force dead code elimination in non-fault-injecting builds */
+	if ( rate == 0 )
+		return 0;
+
+	return inject_fault_nonzero ( rate );
+}
+
+#endif /* _IPXE_FAULT_H */